Manufacturing Engineering Research Papers

1987

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1996, IEEE Transactions on Automation Science and Engineering

This article provides a tutorial introduction to visual servo control of robotic manipulators. Since the topic spans many disciplines our goal is limited to providing a basic conceptual framework. We begin by reviewing the prerequisite... more

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Behavior-based formation control for multirobot teams

by Ronald C Arkin

1998, IEEE Transactions on Robotics and …

New reactive behaviors that implement formations in multirobot teams are presented and evaluated. The formation behaviors are integrated with other navigational behaviors to enable a robotic team to reach navigational goals, avoid hazards... more

Fig. 1. A team of four robotic scout vehicles manufactured for DARPA’s Demo II project. The formation techniques reported in this article were implemented on these robots. Photograph courtesy of Lockheed-Martin.

Fig. 2. An example of how scouts in formation focus their sensor assets so as to ensure complete coverage. Four robot scouts sweep from left to right in a diamond formation. The wedges indicate the sensor focus for each scout. Figure courtesy of Diane Cook of the University of Texas at Arlington [7].

Fig. 4. Formation position determined by various referencing techniques (from left to right: unit-center, leader, neighbor).

Fig. 5. Zones for the computation of maintain-formation magnitude. a position to the left of and abeam Robot 1. Robot 3 is in the controlled zone, so a moderate force toward the desired posi- tion (forward and right) is generated by maintain-formation. In general, the magnitude of the vector is computed as follows:

Fig. 6. Four robots in leader-referenced (a) diamond, (b) wedge, (c) line, and (d) column formations.

Fig. 7. Comparison of (a) leader-referenced and (b) unit-center-referenced diamond formations.

Fig. 8. Shannon and Sally, the two Nomad 150 robots used in formation experiments.

Fig. 9. Telemetry and photos of Shannon and Sally moving into and then traveling in column formation. Top row: column formation telemetry with no obstacles present. Middle row: column formation telemetry with obstacles present. Bottom row: photos of the robots in column formation with obstacles present. The photo sequence corresponds to telemetry in the middle row with obstacles (wastebaskets) present. This experiment was recorded in the foyer of the Georgia Tech Manufacturing Research Center, looking down on the robots from 20 feet above so that formation positions are more easily observed.

Fig. 10. Telemetry and photos of Shannon and Sally moving into and then traveling in wedge formation. Top row: wedge formation telemetry with no obstacles present. Middle row: wedge formation telemetry with obstacles present. Bottom row: photos of the robots in wedge formation with obstacles present. The photo sequence corresponds to the telemetry in the middle row with obstacles present.

Fig. 11. Telemetry and photos of Shannon and Sally moving into and then traveling in line formation. Top row: line formation telemetry with no obstacle present. Middle row: line formation telemetry with obstacles present. Bottom row: photos of the robots in line formation with obstacles present. The phot sequence corresponds to the telemetry in the middle row with obstacles present.

Fig. 13. Illustration of terms used in describing formation behaviors for UGV’s. In this diagram the robot is behind and to the right of the desired position in formation. The robot's position and direction are indicated by Rpos and Raiy. The desired formation position is F,o;. The formation is moving in the direction Fy;,. Fig. 12. A comparison of telemetry from actual robot formation runs (top row) and runs in in simulation (bottom row). From left to right: line, wedge, and column formations.

Fig. 16. Reconstruction of the ground track of DARPA UGV’s depicted in Fig. 17. The pair of robots are shown at three points in time as they move from right to left. They transition from column (right) to wedge (center) to line formations as they traverse the field. Fig. 15. Simulation of two DARPA UGV’s in formation. The robots are moving from left to right in a line formation. The robot at the top of the figure follows a fixed path, while the other robot utilizes behaviors described in the text to maintain a unit-center-referenced line formation.

Fig. 17. Two DARPA UGV’s in formation, from left to right: (a) column, (b) wedge, and (c) line.

afean eae MoToR SCHEMA PARAMETES FOR FORMATION NAVIGATION EXPERIMENTS IN SIMULATION

PERFORMANCE FOR A 90 DEGREE TURN FOR BOTH UNIT-CENTER AND LEADER-REFERENCED FORMATIONS, SMALLER NUMBERS ARE BETTER. THE STANDARD DEVIATION IS INDICATED WITHIN PARAMETERS TABLE II

PERFORMANCE FOR NAVIGATION Across AN OBSTACLE FIELD B. Motor Schema Performance in Turns 50 m from the unit-center. In contrast, the flanking robots in wedge, line, and column formations are 75 m from the unit center.

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A solution to the simultaneous localization and map building (SLAM) problem

by Kamal Othman

2001, Robotics and …

The simultaneous localization and map building (SLAM) problem asks if it is possible for an autonomous vehicle to start in an unknown location in an unknown environment and then to incrementally build a map of this environment while... more

Fig. 1. A vehicle taking relative measurements to environmental landmarks. gorithm in an outdoor environment using a millimeter wave (MMW) radar sensor.

where I,,, is the dim(p;) x dim(p;) identity matrix and 0,,, is the dim(p;) null vector. The augmented state transition model for the complete system may now be written as The case in which landmarks p, are in stochastic motion may easily be accommodated in this framework. However, doing so offers little insight into the problem and furthermore the conver. gence properties presented by this paper do not hold.

Invoking the matrix inversion lemma for partitioned matrices, stationary giving Q = O. Under these circumstances it is conve- nient to use the information form of the Kalman filter to examine the behavior of the state covariance matrix. Continuing with the single landmark environment, the state covariance matrix after this solitary landmark has been observed for & instances can be written as

Fig. 2. The test vehicle, showing mounting of the MMWR and GPS systems. with, and how landmarks are initialized and tracked as the algo- rithm proceeds.

Fig. 3. Test vehicle at the test site. A radar point landmark can be seen in the left foreground. priori knowledge of landmark location to deduce estimates for both vehicle position and landmark locations.

Fig. 4. Vehicle and observation kinematics. for all landmarks: = 1...N. Together, (35) and (36) define the state transition matrix F(-) for the system.

Fig. 5. A typical test run. Only 30% of radar observations correspond to identifiable landmarks. observations alone. The radar receives reflections from many objects present in the environment but only the observations re- sulting from reflections from stationary point landmarks should and the locations that correspond to all the reflections bearing observations. This data set illustrates the im of correct landmark identification, initialization and su andmark quality is employed to initialize and track andmarks, Landmark quality implicitly tests whether be used in the estimation process. Fig. 5 shows a typical test run received by the radar. Only about 30% of the radar observations corre- sponded to identifiable point landmarks in the environment. In addition to these, a large freight vehicle and a number of nearby buildings also reflect the radar beam and produced range and portance bsequent data association. In this implementation a simple measure of potential the land- mark behaves as a stationary point landmark. Range and bearing measurements which exhibit this behavior are assigned a high quality measure and are incorporated as a landmark. T do not are rejected. Mil... 1... .1... ~ ..1. 2... _ Vk. Cd kw we Tw tk CLT eee dt CLT LLL hose that he

Fig. 6. Calculated landmark qualities at the end of the test run. Landmark quality ranges from 1 (for highest quality) to 0 (for lowest quality). Landmarks are marked with a star. Landmarks which are also circled are the artificial landmarks whose locations were surveyed so that the accuracy of the map building algorithm can be evaluated.

Fig. 10. Difference between the actual and estimated location for landmark 1. The 95% confidence limit of the difference is shown by dotted lines.

Fig. 13. Standard deviation of the landmark location estimate for all detected landmarks. As predicted, the uncertainty in landmark location estimates decrease monotonically.

vark1, Fig. 12. Decreasing uncertainty in landmark location estimates.

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Inventory management and production planning and scheduling

by Mayflor Tomarong

1998

This list contains errors last updated June 4, 2008. If you are aware of errors not listed here, please su them to the authors at http://mba.tuck.dartmouth.edu/pages/faculty/dave.pyke/inventory_management/submit_error.htm Instructors should note that the spreadsheets available with the Instructor's Resource Guide may have slightly different equation and table numbers from the text.

Dys(No) = probability that the net stock at a random point in time takes on the value 1p

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Coverage Control for Mobile Sensing Networks

by jorge cortes

2002, IEEE Transactions on Robotics and Automation

This paper describes decentralized control laws for the coordination of multiple vehicles performing spatially distributed tasks. The control laws are based on a gradient descent scheme applied to a class of decentralized utility... more

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A literature and practice review to develop sustainable business model archetypes

by Nancy Bocken and

2014, Journal of Cleaner Production

Eco-innovations, eco-efficiency and corporate social responsibility practices define much of the current industrial sustainability agenda. While important, they are insufficient in themselves to deliver the holistic changes necessary to... more

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State-of-the-art in product-service systems

by lc etil

2007, Proceedings of the …

A Product Service-System (PSS) is an integrated combination of products and services. This western concept embraces a service-led competitive strategy, environmental sustainability, and the basis to differentiate from competitors who... more

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Does Corporate Social Responsibility Affect the Cost of Capital

by Dev Mishra

2010

Recent years have seen a considerable increase in the literatures concerning the separate areas of corporate social responsibility and corporate tax aggressiveness. However, comparatively little scholarly attention has been paid to the... more

Fig. 2. P : aay ea ‘ti LS structural model with significant path coefficients. ***p <0.01, **p <0.05, *p < The results of the PLS structural model analysis are depicted in Figure 2. The GoF was computed, yielding GoF = 0.4223, indicating acceptable validity for the model.

The results of the measurement model for the full sample are summarized in Tables 2-4. As Table 2 shows, the industry construct was removed from the model and not used i analysis because of its low item loadings and lack of composite reliability and conve n further rgent validity. All the items of final model loaded on their respective constructs and were greater than 0.5. The factor loadings from the final PLS measurement model are presented in Table 3. Convergent validity appeared adequate for all constructs, as AVE exceeded 0.5 in all The discriminant validity of the constructs is presented in Table 4, which shows that diagonal AVE values exceed all other scores, suggesting sufficient discriminant validity.

Estimation of the measurement model parameters (full sample, n = 83).

The results from the structural model, presented in Table 5, indicate how the different dimensions of corporate social responsibility affect tax aggressiveness. The findings reveal a positive and significant relationship between CSR_S and TAG (0.2899, t = 1.8566, p <0.1), providing support for hypothesis H;. Indeed, the more the firms engaged in human resources activities, human rights in workplaces, and community involvement, the higher their ETRs were and, thus, the lower the likelihood that they would be tax aggressive in nature. The results also show a negative and significant relationship between CSR_ECO and TAG (- 0.3554, t = 2.5659, p < 0.05), suggesting that the more firms engaged in business behavior efforts, the lower their ETRs were and, thus, the higher the likelihood that they would be tax aggressive in nature. Hence, hypothesis H3 is supported. Moreover, the findings show no significant relationship between CSR_CG, and TAG, thus rejecting hypothesis H», Finally, the results also reveal no significant relationship between CSR_ENV and TAG, rejecting hypothesis H,.

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Analytical prediction of stability lobes in milling

by Y. Altintas and

1995

Figure 1: Dynamic model of milling with two degrees of freedom

The dynamic milling expression (8) is therefore re- duced to the following where the integrated functions are given as:

Figure 2: A single single degree of freedom system: Comparison of the predicted chatter limit with the published data (Minis and Yanu- shevsky [1993], analog data is from Opitz [1968] and Sridhar et al. [1968]).

Milling with a 2-DOF Cutter : A two DOF milling system example is taken from Smith and Tlusty [12]. This is a half immersion-up milling of Figure 3: Analytical, multi frequency and time domain stability limit predictions for a case an- alyzed by Smith and Tlusty [1990].

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Reference architecture for holonic manufacturing systems: PROSA

by Luc Bongaerts

1998, Computers in Industry

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Stochastic models of manufacturing systems

by JOHAN OSCAR ONG

1993

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A new approach to visual servoing in robotics

by Joji Trivandrum

1993, Geometric Reasoning for Perception …

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Titanium alloys and their machinability—a review

by Emmanuel O. Ezugwu

1997, Journal of Materials Processing Technology

Although there have been great advances in the development of cutting tool materials which have significantly improved the machinability of a large number of metallic materials, including cast irons, steels and some high temperature... more

Fig. 1. Distribution of thermal load when machining titanium and steel (after Konig [2 1)).

Fig. 2. Normal and tangential stresses in machining (after Konig {21)).

Fig. 3. Effect of cutting speed and feed on tool life in tuning Ti-6AL--4V (after Kahles et al. [10).

Fig. 4. Effect of cutting speed and depth of cut on tool life in turning Ti-5Al-2Sn (after Chandler [13]).

Fig. 6. Rotary cutting tools (after Ping Chen [66}).

Fig. 5. Ledge tool (after Komanduri and Lee [64.05)).

Fig. 8. Tool wear curves in machining Ti-6Al—4V (after Ping Chen [67,68]). 4, As a basic rule, a cutting fluid must be applied when machining titanium alloys. The correct use of coolants during machining operations greatly extends he life of the cutting tool. Chemically active cutting luids transfer heat efficiently and reduce the cutting forces between the tool and the workpiece. to the high cutting stresses and temperatures near the cutting edge, which greatly influence the wear rate and hence the tool life. Flank wear, crater wear, notch wear, chipping and catastrophic failure are the prominent failure modes when machining titanium alloys. Flank and crater wear may be attributed to dissolution-diffu- sion, attrition and plastic deformation, depending on the cutting conditions and the tool material, whilst

Fig. 7. Measured temperature in turning Ti-6A1-4V (after Ping Chen [66}).

4uue = Average unit power requirements for turning, drilling and milling (horsepower per cubic inch/minute) (after Kahles et al. [10] Table 2 milling, tapping, broaching and planing), drilling and reaming being performed best by high-speed steel tools. Freeman [25] established the better performance of the WC/Co grades, no matter which wear mechanism is taking place. It has been found that the best grades in cutting applications are the C-2, represented by ISO K20 [37-39]. Dearnley, Grearson and Aucote [23,40], carrying out many trials involving various tool materi- als in the continuous turning of Ti-6A1—4V, also confi- rmed the K grade carbides as the best choice. They suggested that those WC/Co alloys with Co contents of 6 wt% and a medium WC grain size (about 0.8 and 1.4 um) gave the optimum performance. A recent study [41] advises that straight cobalt-base tungsten carbide cutting tools implanted with either chlorine or indium are very effective in the machining of titanium and their alloys.

Typical parameters for machining Ti-6AI-4V jet engine components (after Kahles et al. [!0]) ®Axial depth. Radial depth is up to two-thirds the cutter diameter. Table 3

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The servitization of manufacturing: A review of literature and reflection on future challenges

by Tim Baines

2009, Journal of Manufacturing Technology Management

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Large-scale purification of single-wall carbon nanotubes: process, product, and characterization

by Satpal Sangwan

1998, Applied Physics A: …

We describe, in detail, a readily scalable purification process capable of handling single-wall carbon nanotube (SWNT) material in large batches. Characterization of the resulting material by SEM, TEM, XRD, Raman scattering, and TGA shows... more

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Nanosystems- Molecular machinery, manufacturing, and computation(Book)

by Abubacker Shihab

1992, New York, NY: John Wiley & Sons, Inc, 1992.

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Vibration control using semi-active force generators

by Dean Karnopp

1974, Journal of Engineering for Industry

The invention is based on a method and system for regulation and/or control of an automobile chassis where between the vehicle body and at least one wheel there is at least one actuator actuated by actuation sig nals for exertion of... more

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Metal matrix composites: production by the stir casting method

by Atul Gaur

1999, Journal of Materials Processing Technology

Combining high specific strength with good corrosion resistance, metal matrix composites (MMCs) are materials that are attractive for a large range of engineering applications. Given the factors of reinforcement type, form, and quantity,... more

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A Petri net based deadlock prevention policy for flexible manufacturing systems

by Javier Martinez

1995, IEEE Transactions on Robotics and Automation

In this paper we illustrate a compositional method for modeling the concurrent execution of working processes in flexible manufacturing systems (FMS) through a special class of Petri Nets that we call S 'PI?. In essence, this class is... more

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Leader-following consensus of multi-agent systems with and without time-delay

by Huan Pan

2010

The leader-following consensus problem of multiagent systems over finite fields Fp is considered in this paper. Dynamics of each agent is governed by a linear equation over Fp, where a distributed control protocol is utilized by the... more

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Structural properties and classification of kinematic and dynamic models of wheeled mobile robots

by Brigitte D'Andréa-Novel

1996, IEEE Transactions on Robotics and Automation

The structure of the kinematic and dynamic models of wheeled mobile robots is analyzed. It is shown that, for a large class of possible configurations, they can be classified into five types, characterized by generic structures of the... more

We note that the nonslipping constraints of to the 2 fixed wheels are equivalent (see the first 2 rows of C). Hence, the matrix CT has a rank equal to 1 as expected. Example 4: Type (2,1): Robot with one conventional cen- tered orientable wheel and two conventional off-centered ori- entable wheels, Fig. 9.

Fig. 2. Fixed and conventional centered orientable wheels. augle @. The rotation angle of the wheel around its (horizontal) axle is denoted y(t) and the radius of the wheel is denoted r.

Obviously rank [Cf(G.)] < 3. If rank [CT(6.)] = 3, then R(@)E = 0 and any motion in the plane is impossible! More generally, the limitations of the mobility of the robot are related to the rank of CY. This point will be discussed in detail hereafter.

Fig. 6. Omnidirectionnal robot—Type (3,0). Three sweedish wheels. have been presented above. We restrict our attention to robots with three wheels. As we have shown in Section II-B, the wheels of a mobile robot are described by (at most) six characteristic constants:

Example 5: Type (1,1): Robot with two conventional fixed wheels on the same axle and one conventional centered orientable wheel (like the tricycles of the kids), Fig. 10.

CAMPION et al.: STRUCTURAL PROPERTIES AND CLASSIFICATION OF ROBOTS

The configuration model is characterized by $(q), defined as It results that the degree of nonholonomy is equal to 5— 3 = 2, while the number of coordinates that can be eliminated is

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MR fluid, foam and elastomer devices

by Kavi Arasan

2000, Mechatronics

Magnetorheological (MR)¯uids, foams and elastomers comprise a class of smart materials whose rheological properties may be controlled by the application of an external magnetic ®eld. MR¯uids are liquids whose¯ow or shear properties are... more

Fig. 2. The quadratic dependency of MR fluid stress on particle saturation magnetization. Each data point corresponds to an MR fluid made from a different iron-based alloy. are seen to exhibit sub-quadratic behavior. Indeed the MR fluids exhibit an approximate power law index of 1.75 at low and intermediate fields. This subquadratic behavior is attributed to gradual particle saturation with increasing field and is, in part, predicted by contemporary models of magnetorheology [22,28]. Beyond fields of about 0.1 Tesla, the effects of bulk magnetic saturation are revealed as a departure from power law behavior. The stress response ultimately plateaus as the MR fluids approach complete magnetic saturation. Simple theory predicts that the ultimate yield stress of MR fluids is proportional to oJ? where > is the particle volume fraction and J, is the particle saturation magnetization. Fig. 2 demonstrates the quadratic dependency of MR fluid yield stress on particle saturation magnetization.

Fig. 1. Shear stress versus applied field for two commercial MR fluids.

Fig. 3. Magnetic properties of two commercial MR fluids.

Fig. 4. The effect of average composite flux density on the elastic modulus for MR elastomers containing 10% (A), 20% (0) and 30% (x) iron by volume (adapted from Jolly et al. [29]). Experiments on double lap shear specimens of MR elastomers were reported by Jolly et al. [29]. Testing involved recording the complex modulus of various

Fig. 5. Basic operation modes for MR fluids. The bandwidth of controllable fluid devices is largely determined by factors extrinsic to the fluid such as the dynamics associated with field generation. These

Fig. 6. Rotary MR fluid brake (a) and linear MR fluid damper (b).

Fig. 7. Simple, low cost MR foam devices: (a) vibration damper; (b) damper performance; and (c) rotary caliper brake.

Several commercially available MR fluids [34] Table 2

Typical MR fluid properties [10] Table 1

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Metal Fabrication by Additive Manufacturing Using Laser and Electron Beam Melting Technologies

by Edwin Martinez

2012, Journal of Materials Science & Technology

Selective laser melting (SLM) and electron beam melting (EBM) are relatively new rapid, additive manufacturing technologies which can allow for the fabrication of complex, multi-functional metal or alloy monoliths by CAD-directed,... more

Fig. 1 EBM(a) and SLM (b) system schematics. Atomized Cu powder example; SEM image (c). See text for discussion of numbered system components

ig. 12 3D-optical microscopy image composite section view for alloy 625 component fabricated by EBM. The build direction is noted by the arrow (lower right). NisNb bet precipitate columnar arrays are spaced ~2-3 wm

‘ig. 16 3D-optical micrograph composite section view for 17-4PH stainless steel nitrogen atomized powder fabricated in argon gas (N2-Ar) fabricated by SLM. The build direction is shown by arrow at lower right

Fig. 14 3D-optical micrograph composite section view for an alloy 625 component fabricated by SLM. The columnar microstructural architecture is com- posed of NisNb bct plates

“ig. 15 3D-optical micrograph composite section view for a Co-base superalloy component fabricated by EBM. The columnar microstructural architecture is composed of Cra3Ce6 cubic precipitates shown in the magnified 3D TEM insert

Fig. 18 3D-optical micrograph composite section view for 17-4PH stainless steel nitrogen atomized powder fabricated in nitrogen gas (N2-N2) by SLM. The build direction is shown by arrow at lower right

‘ig. 17 X-ray diffraction (XRD) spectra corresponding to the horizontal (top) and vertical (bottom) refer- ence planes corresponding to Fig. 16. The vertical reference plane is parallel to the build direction

Fig. 20 CAD models for EBM or SLM fabrication of open-cellular structures. (a) Dode-thin (Materialize™) Software element-based mesh model. (b) Stochastic foam model based on micro-CT scan element

Fig. 21 EBM-fabricated foam (a) and mesh (b) structures of Ti-6Al-4V. Corresponding densities are noted

ig. 23 Relative stiffness (E/E.) versus relative density (p/p) for open cellular structures fabricated by EBM. Slope of 2 corresponding to Eq. (1) is noted. Ti-6Al-4V data from!4). Cu data from!!”). Co-base and Ni-base alloy data from!?°

‘ig. 22 3D-optical micrograph section composites for struts of mesh structures fabricated by EBM. (a) Ti-6AL4V. (b) Co-26Cr-6Mo-0.2C. Arrow at. left denotes the build direction

4. Orthopaedic (knee) implants. (a) EBM-fabricated and partially finished Co-base femoral implant. Note surface mesh to contact the prepared femoral bone surface (arrow). (b) X-ray showing total knee replace- ment components. f indicates a Co-base (femoral) appliance while t indicates a Ti-6AI-4V tibial appliance. These are standard cast or wrought products cemented into the respective bones

25 Extension of the conventional materials science and engineering tetrahedron representing connections be- tween material structure-properties-processing-performance to a new pyramid paradigm; including mi- crostructural architectures through processing opportunities afforded by EBM and SLM fabrication

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United Nations Environment Programme

by Annie Bezbatchenko

2011, Green Health: An A-to-Z Guide

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Advanced monitoring of machining operations

by D. Dornfeld and

2010, Cirp Annals-manufacturing Technology

CIRP has had a long history of research and publication on the development and implementation of sensor monitoring of machining operations including tool condition monitoring, unmanned machining, process control and, more recently,... more

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Optimization of the simultaneous localization and map-building algorithm for real-time implementation

by Jose Guivant

2001, IEEE Transactions on Automation Science and Engineering

This work addresses real time implementation of the Simultaneous Localization and Map Building (SLAM) algorithm. It presents optimal algorithms that consider the special form of the matrices and a new compressed filter that can... more

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Strategic sustainable development--selection, design and synergies of applied tools

by K.-h. Robèrt

2002, … of Cleaner Production

The number of tools and approaches to develop sustainability is growing rapidly. Sometimes they are presented as if they are contradictory or in competition. However, a systems approach consistent with basic principles and the... more

In the following section, a number of concepts and associated institutions will be related to the model presented in section 1. All of those institutions are work- ing with sustainability as the ultimate goal, and have elaborated working programs that take a systems per- spective of the kind presented in the model into account. However, their “entry points” into the model vary. This means that each has its distinct primary focus (highlighted in the respective figures, see below) from which other aspects of sustainability have been elabor- ated as secondary consequences to the primary focus. This is important to recognize in order to avoid misun- derstandings of the presentation. Differences in primary focus should lead, almost per definition, to some important differences in perspectives and experiences. When the different tools are considered, this potential synergy ought to be utilized in conscientious and deliber- ate ways, rather than being perceived solely as alterna- tives, or even “competitive” alternatives. This process has led to the development of The Natu- ral Step Framework TNSF [for references, see 10] for decision-making. It is designed for qualitative problem analysis, community building, and for the development of investment-programs in business corporations and municipalities. Its primary focus is on a comprehensive definition of level 2 in the presented model, resulting in the development of the system conditions, and on back- casting and other essential elements for strategic plan- ning in level 3 to comply with level 2 (see figure below). This intellectual approach is dependent on tools developed by others to cover the other aspects of the model. This includes more quantitative assessments of the objective of meeting the system conditions (as pro- vided by other institutions like the Factor 10 Institute, see below), and various tools to monitor the transition, for instance tools for management like ISO 14001 and for indication of progress such as LCA and the Factor concept (level 5). Furthermore, since the whole idea of TNS is to develop and disseminate a framework to guide

Ecological Footprinting (EF) [3] is a way of “bench- marking” all dematerializations under the system con- ditions (level 2 in the model). One of the major differ- ences to Factor 10 is that, with Ecological Footprinting, the outcomes of various activities in society are not determined by factors (i.e. incremental units related directly to the specific materials or material flows). The outcomes are instead measured and aggregated into units of area, i.e. as a reduction or an increase in the ecological area needed to support the activities. This is then related to an estimation of the total life sustaining area of the a a Efforts have also been done to relate the material intensity to the desired utility, MIPS (material intensity

EF is an overall measuring tool to get a tangible over- view of our performance with regard to sustainability, and is unique in its capacity to communicate very directly how life style and technical competence relate to such a perspective. EF inherently contains aggregated data concerning dematerializations and certain substi- tutions under all system conditions. Consequently, it has certain limitations when we are studying isolated flows of society, for instance when various sub-systems are going to be evaluated and compared to each other in a planning procedure. Here, the more flexible Factor con- cept can be used. Both concepts are relevant for their In order to avoid misleading conclusions, ZEF seeks to develop Life-Cycle-Analysis (LCA) techniques so that this tool can cover the full aspects of sustainability

and not just arbitrarily chosen data on emissions and energy use [37]. sustainable technology up to a viable product in the mar- ket is an essential consideration in the approach of SDT. STD focuses on some well known aspects of sus- tainability as the primary objectives of planning, and like TNSF, it also puts primary focus on the relation between the objective of planning on one hand (sustainability), and principles for the process to reaching the objectives on the other. More specifically [41]:

Sustainable Technology Development describes the Dutch National Research programme of the same name, which has sought ways to influence innovative processes and outcomes in favour of accelerating the development of technologies and maximising the contribution that technology can make toward sustainable development. The fact that it takes decades to develop an option for Thus STD, like TNS, applies backcasting and inte- grates social tools and objectives as essential elements for planning, and acts as facilitators

Natural Capitalism [9] attempts to define and describe means to connect human institutions including business within the flow of natural cycles including ecosystem services. To do so it is necessary to integrate all relevant aspects of society into an economic framework used for decision-making, particularly those aspects that are becoming increasingly scarce, or are at increasing risk. Hence, our “global commons” — the well-being of glo- bal ecosystems and the long term quality of life of all people — must be integrated into any comprehensive economic model. Such an economic model recognizes the critical relationship between the pursuit of human productivity, and thus higher income, and the greater use of natural capital. Natural capital includes not only the resources demanded by business and society, but also includes the flow of services that flow from ecosystems that are not monetized or valued. Natural Capitalism describes a set of fundamental assumptions necessary for this integration of economy, ecology and societal demands. These include viewing the economy as a sub- set of the global environment; future economic growth will be limited by natural capital rather than human- made capital; radical increases in resource productivity Because of UNEP’s central position in Society’s inter- national policy making, there are some major differences between Cleaner Production, and the other institutions presented in this survey. As demonstrated by the launch of the International Cleaner Production Declaration [44], the Cleaner Production Programme objective is to cata- lyse, in all parts of the world, Cleaner Production activi-

4, Discussion will be necessary to eliminate pressure on natural capital, requiring a full valuation of all forms of capital in market systems, and a shift in focus on services that meet human needs rather than goods per se as a means to address inequalities in income and well-being and reinforce resource productivity. The base assumptions are then applied directly to both short and long term business and governmental decisions as part of an overall societal strategy.

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Product-services as a research field: past, present and future. Reflections from a decade of research

by Ursula Tischner

2006, Journal of Cleaner Production

In the last decade many researchers, institutes and programs in the EU paid attention to product-service systems (PSS). Given this massive effort, it is time to take stock. Is PSS research a theoretical field in its own right? Is the PSS... more

Fig. 1. The SCORE! — project knowledge communities relevant for system innovation [25].

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Towards energy and resource efficient manufacturing: A processes and systems approach

by Joost R Duflou

2012, CIRP Annals - Manufacturing Technology

Fig. 1. System boundaries of a unit process [111]. While some preliminary environmental studies for machine tools in material removal processes (e.g. turning and milling) indicate that more than 90% of the environmental impact is due to the consumption of electrical energy during the use stage [23], other authors reporting detailed analysis observe significantly larger contributions of the machine tool construction [9,42, 172,229]. With a minimum of approximately 83% and 60% of

Fig. 2. CO2PE! - UPLCI - Methodology [111].

Fig. 4. Power levels during the productive modes of an EOSINT P700 Selective Laser Sintering machine tool [110].

Fig. 3. Time distribution for SLS production modes (PA2200, layer thickness of 120 pm) [110]. The majority of discrete part casting operations occurs through sand casting (60%) [203]. The sand casting process involves pouring of molten metal into a mold composed primarily of sand and binders. The binders used are primarily chemical (thermal

Fig. 5. Time distribution for the production modes of the air bending process [52]. time share of the standby mode (mode 1) is very high as indicated in Fig. 5. On the other hand, the power levels during the standby mode are significant, ranging from 1.4 kW to 5 kW for conven- tional hydraulic press brakes with a maximum capacity between 80 and 170 ton. Similar conclusions were drawn by Shi et al. [179] for stamping processes.

Fig. 8. Distribution of the environmental impact during 1 h of EDM roughing [109].

Fig. 7. Average fixed energy breakdown adapted from [121]. As shown in Fig. 7, an average breakdown of the fixed energy ‘onsumption of machining processes is given by Li et al. [121].

Fig. 10. Specific energy demand for milling processes as function of the material removal rate (MRR) [43].

Fig. 9. Relative importance of different energy saving measures for compressed ai. systems. Adanted frnm [170] 2.4.2.1. Selective actuation of non-continuously required devices. An easy and highly effective way to reduce the electrical energy consumption can be found in selectively shutting down devices of which the functionality is not required in specific operational

Fig. 11. Power consumption in cutting mode in function of the laser output level for 7 different laser cutting machines (3 configurations combined with different CO2 laser sources with indication of the maximum achievable output level) [52]. Clarens et al. [27] provided a quantitative assessment of emissions and energy consumption as well as a semi quantitative assessment of health impacts associated with environmentally

Fig. 12. Multi-machine ecosystem. 3.1.1.1. Modeling methodologies of energy flows in an ecosystem. The foundation for description, acquisition and analysis of all energetic flows into and out of a multi-machine ecosystem are the energy,

Fig. 14. Influence of PPC on energy demand [163]. As pointed out above, the energy and resource consumption of process chains is rather dynamic depending on the state of the

Fig. 16. Production facility as a complex control system [82]. The complexity and sophistication in the organization of manu- facturing systems and processes necessitate a keen understanding of the organization for accurate environmental analysis. To assist in this effort, manufacturing can be broken into ‘levels of study’ across two orthogonal frameworks, spanning organizational and temporal levels.

Fig. 15. Paradigms for simulating energy flows in manufacturing systems [86,196].

Fig. 18. Schematic of strategy for increasing energy efficiency in manufacturing companies spanning process to facility level consumption and impacts [82].

Fig. 17. An integrated view of manufacturing design levels and the decisions they contain. Arrows represent the flow of information from one decision to another. Adapted from [165].

Fig. 19. Schematic of various energy control loops at the different levels of the facility [211].

Fig. 20. Industrial symbiosis at Kalundborg. Adapted from [190].

Fig. 21. The progression of industrial symbiosis relationships. Adapted from [24].

Fig. 22. Electricity generation in 2008 by type and country (top 20 countries) [204].

Fig. 23. Evolution of electricity prices in European countries [62,83].

Environmental parameters of sample batch for SLS processing [110]. Table 1

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Lean viewed as a philosophy

by Jojo Elhelbawy

2006, Journal of Manufacturing Technology …

Purpose -The purpose of this paper is to act as a meticulous conceptual paper probing the contemporary view towards lean and illustrate that, despite its discernible benefits, the implementation record suffers as the prevailing opinion... more

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Costs and carbon emissions for geopolymer pastes in comparison to ordinary portland cement

by Shankar Sanni

2011, Journal of Cleaner Production

Geopolymer concrete is seen as a potential alternative to standard concrete, and an opportunity to convert a variety of waste streams into useful by-products. One key driver in geopolymer development is the desire to reduce greenhouse gas... more

Figure 2: Life cycle stages considered for production of geopolymer feedstock Figure 1: Schematic of production of geopolymer concrete The approach taken in this work has not considered formally the durability or service life of geopolymers as opposed to OPC concretes. This was omitted on the grounds that the service life is still yet to be clarified for geopolymers as they are an emerging product. However, the testing of geopolymer concrete under a variety of applications has indicated that the durability and service life is likely to be better than that of traditional concretes. Hence the assumption of equal durability and service life is likely to underestimate the benefit of geopolymers over OPC-based concretes or overestimate the cost. This is especially relevant in applications such as railway sleepers, where a schedule of replacement is expected. Recycling of end-of-life products have also been neglected for this assessment. It may be

The inventories of emissions, costs and energy usage were developed through a literatur review of reported values and some theoretical estimates where no data was available Attempts have been made to ensure that the data are used on a comparable basis, so that ther is not a distortion of the boundaries of the analysis. Importantly, waste products (i.e. fly as and silica fume’) are not allocated any of the emissions from the processes that produce ther aS a waste stream. The justification for this approach is that these wastes would not b generated without the production of their associated commercial product (e.g. electricity i the case of fly ash and silicon in the case of silica fume), and hence the emissions should b allocated to their respective commercial products. This assumption means that, apart fror any post-collection processing, these materials come with no “embodied impacts”. Energy data have been obtained from the available literature — mostly this has bee

Figure 7: Geopolymer feedstock production metrics - error bars indicate the range of values found in the literature (NaOH and sodium silicate figures quoted here are on the basis of 1t of NaOH or sodium silicate solid, although the actual supply will most likely be as a solution. For sodium silicate we have used a SiO, : Na,O weight ratio of 2.0.) Figure 8 gives estimates of the how much a particular feedstock could be used before the resulting geopolymer would have an equal greenhouse gas emissions or cost impact to that of OPC. This figure can be taken as the absolute limit for a given feedstock in producing the equivalent geopolymer to replace one tonne of OPC. The data are presented on the basis of production alone and production plus transportation. The results indicate that the cost limitations — especially with the cost of transportation included — are likely to be the limiting

Figure 9 shows a comparison between 4 potential geopolymer mixes (see Table 3 for mix details) on a production basis alone and a production plus transportation basis. This indicates hat geopolymers can range in potential cost and greenhouse gas competitiveness from much ower (approximately 72% reduction in cost and 97% reduction in greenhouse emissions) to he same or higher than an OPC mixture (up to approximately eight-fold cost increase and 14% increase in greenhouse emissions). On a production-only basis, the geopolymer is seen o be significantly better in greenhouse emissions terms, and potentially competitive on a cost basis. However, when transportation is included the benefits are less clear — for short distances there is a definite benefit but for long distances there is a negative impact.

Figure 9: Example mixes - comparison of greenhouse gas emissions and cost on a dry tonne basis (Comparison of feedstock production only and feedstock production with transport included (designated “—transport’’) emissions and costs) Table 3: Example geopolymer paste mixes (wt % without added water)° ‘igure 9: Example mixes - comparison of greenhouse gas emissions and cost on a dry tonne basis

Figure 10: Comparison of contributions to a "typical" Australian geopolymer paste and OPC To illustrate the method of calculation: would be expected for the “typical” geopolymers using the above four mixes are shown in Table 4. These typical values and the corresponding equivalent for OPC are also shown in Figure 10, as well as the contribution that the production of each feedstock and transport make to the overall cost and emissions. This analysis shows that geopolymers from typical feedstock sources, typically in close proximity to the point of usage, could produce improvements of up to 64% in terms of greenhouse gas emissions over OPC. In cost terms, the performance of geopolymers showed that an improvement over OPC is possible, with costs ranging from 7% lower to 39% higher than OPC. This indicates that geopolymers are likely to be disadvantaged on price performance under current pricing structures and without a carbon price. Figure 10 further indicates that the key source of emissions for the geopolymer mixes examined here is caustic soda. Thus one of the important research questions for geopolymer development to improve the greenhouse impacts of their product even further must be how to reduce the dependence on raw caustic soda production, or to source this feedstock from lower-emitting producers.

Table 1: Geopolymer feedstock and OPC transport and emissions data and reference:

“Maximum distances and mode of transport are selected as those which maximise CO, emissions; * values assumed to be “typical” for Australia > Imports of cement to Australia have been growing in recent years and may contribute 10-20% of the market however, they are not included in this assessment.

Given the varia Australia, it was thought to be important to find a typical value of t This typical va ue could then be used as a ‘first guess’ estimate for bility in the emissions and costs for geopolymers produced from feedstocks in he emissions and cost. comparison with OPC sroducts. Based on an understanding of the various feedstock production drivers, it was letermined tha sontext would be the minimum value for fly ash, sodium silicate, gi und the average value for NaOH and metakaolin. The values for green the transportation distances to find the “typical” value in an Australian bbsite and silica fume, house gas and cost that

Table 4: Typical greenhouse gas emissions and costs for four geopolymer mixes compared with OPC

Table 6: Sensitivity of emissions to transport distance underestimation The results of this study indicate that it is not possible to make a simple sustainability comparison on the use of OPC and geopolymers. This is due to the significant impact of reagent transport and variability in the source of energy and technology used to produce the reagents. Transport has been minimised for OPC, as it is an established product; however, geopolymers are yet to go through this cycle of scale-up. Large scale geopolymer use is likely to lead to lower costs due to large orders of reagents. Even so, there seems to be significant potential for geopolymers to be cost effective and environmentally beneficial. Ls a) a: Cy , i: a: a: ey: i: ih i 7 nn On yy i : 7 a: ey cs fon |

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The Future of Industrial Communication: Automation Networks in the Era of the Internet of Things and Industry 4.0

by Thilo Sauter

IEEE Industrial Electronics Magazine

ith the introduction of the Internet of Things (IoT) and cyberphysical sys tem (CPS) concepts in industrial appli cation scenarios, industrial automation is undergoing a tremendous change. This is made possible in part by recent advances... more

MARTIN WOLLSCHLAEGER, THILO SAUTER, AND JURGEN JASPERNEITE

FIGURE 2 — The complexity of communication in industrial automation systems. Today, RTE has become a standard in the industrial automation domain. Un- fortunately, there is currently no single standard but many different mutually incompatible implementations. The ex- isting RTE solutions are based on Fast Ethernet and can be divided into three classes, which differ in the achieved re- al-time performance and the necessary extensions of the IEEE 802 standards, as shown in Figure 3 [33]. In class A, the real-time services are realized above the transport layer with cycle times in the range of 100 ms. Modbus-Inter- face for Distributed Automation (IDA), Ethernet/industrial protocol (IP), and Foundation fieldbus (FF) high-speed Ethernet are implementations that be- long to this class. These were the earli- est implementations of industrial Ether- net. They build on the entire transport control protocol (TCP)/IP suite and use best-effort bridging. In class B, the real-time services are realized directly on top of the media access control (MAC) layer by using approaches like

FIGURE 3 — The classification scheme for RTE.

FIGURE 5 — The three levels of industrial communication: application, communication services and middleware, and transport protocols. API: application programming interface.

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Corporate social responsibility in the mining industry: Exploring trends in social and environmental disclosure

by Babudhan Singh

2006, Journal of Cleaner Production

In recent years, concerns about the sustainability and social responsibility (CSR) of businesses have become an increasingly high profile issue in many countries and industries, none more so than the mining industry. For mining, one... more

Fig. 1. Reporting timeline of AngloGold Ashanti.

The pros and cons of electronic information provision (adapted from Elvins [41] and Scott and Jackson [42])

The temporal development of Social and Environmental reporting in the top 10 mining companies from 1999 to 2003*

The policy content of social and environmental disclosure of the top 10 mining companies’* Table 3

Classification of top 10 mining companies according to reporting formats (adapted from Satterbaxter [57])

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Temperature dependence of the mechanical properties and the inner structures of natural rubber reinforced by in situ polymerization of zinc dimethacrylate

by Michael Pecht

2013, Journal of Applied Polymer Science

In this work, the tensile property of natural rubber (NR) reinforced by zinc dimethacrylate (ZDMA) at various temperatures was studied. The results showed that the strain-induced crystallization of NR chains at larger elongation and the... more

Figure 6. Covalent crosslink density of the composites stretched at vari- ous temperatures. (Solid represents unstretched; hollow represents stretched to failure). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] Above 120°C, the NR/ZDMA composites show an apparent increase in crosslink density whereas the neat NR and NR/10 phr ZDMA show a notable decrease at such high temperatures. The increase in crosslink density is an abnormal phenomenon, which is not the actual value. It is obvious that some chemical reaction occurs during stretching at such high temperatures. Note that the crosslink density of the samples preheated at

Figure 1. Effect of preheating period on the crosslink density. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] Polymer physics structure and weak chemical structure are de- pendent on the temperature. Study on the temperature depend- ence of the mechanical properties contributes to the under- standing of structure of the material. Generally, the motion of rubber chains is enhanced while the weak chemical interaction and physical adsorption between filler—filler, filler-rubber mo- lecular, and rubber molecular—molecular are severely reduced at high temperature, resulting in the dissatisfactory mechanical properties.

Figure 2. Tensile strengths at various temperatures. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com. ]

Figure 3. Elongations at break at various temperatures. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary. com. ]

Figure 4. Permanent sets after stretching at various temperatures. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com. }

Figure 5. Total crosslink density of the composites stretched at various temperatures. (Solid represents unstretched; hollow represents stretched to failure). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com. ]

Figure 8. Photograph of the NR/40 phr ZDMA composite after thermal aging for 24 h at different temperatures: (a) 80°C, (b) 100°C, (c) 120°C, and (d) 150°C. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] The strain-stress curve reflecting the whole tensile course of the rubber composite is extremely helpful for understanding the

Figure 7. Ionic crosslink density of the composites stretched at various temperatures. (Solid represents unstretched; hollow represents stretched to failure). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com. ]

Figure 9. Strain—stress curves of NR reinforced by ZDMA (40 phr) at var- ious temperatures. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com. ]

Figure 10. Strain sweep on the neat NR: (a) G; (b) G’. [Color figure can be viewed in the online’ issue, which is available at wileyonlinelibrary.com. ]

Figure 11. Strain sweep on the NR/30 phr ZDMA composite: (a) G; (b) G". [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com. ]

Figure 12. TG (a) and DTG (b) curves for NR and NR/ZDMA (30 phr) in nitrogen atmosphere. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] To evaluate the effect of ionic crosslinks on the thermal stability, the sample of NR/30 phr ZDMA was swollen in the mixture of toluene and chloroacetic acid for 5 days to destroy ionic cross- links, then extracted by acetone for 24 h. As shown in Figure 12(a), the negligible residual weight verifies that all the ionic crosslinks have been cut off, and the Zn** have been replaced by H* which have been removed via acetone extraction. As shown in Figure 12(b), the second degradation peak is attrib- uted to the degradation of polymerized methacrylic acid (Poly- MMA) resulted from the swollen treatment. The resulting ther- mal stability shows a little decrease. The complete decomposi- tion temperature is reduced to 475°C. The two maximum rate decomposition temperatures (Tax) are 2 and 33°C lower than

Table I. Retentions of the Tensile Strength at Various Temperatures

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Data Association In Stochastic Mapping Using the Joint Compatibility Test

by José Neira

2002, Robotics and Automation, IEEE …

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A comparison of rapid prototyping technologies

by duc pham

1998, International Journal of Machine Tools & Manufacture

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Future Energy Systems: Integrating Renewable Energy Sources into the Smart Power Grid Through Industrial Electronics

by Thilo Sauter

2000, IEEE Industrial Electronics Magazine

I ndustrialization and economic development have historically been associated with man's ability to harness natural energy resources to improve his condition. Based on this definition, two industrial revolutions occurred in the 18th and... more

Meeting the global demand for en- ergy is now the key challenge to sus- tained industrialization. Furthermore, modern power distri- bution systems made abundant energy reliably available and rela- tively independent from the plant location. More than two centuries of past industrialization exploited non- renewable energy resources, how- ever, often with undesirable side effects such as pollution and other damage to the natural environment. In the second half of the 20th century, extraction of energy from nuclear processes grew in popularity, reliev- ing some demands on limited fossil fuel reserves, but at the same time, raising safety and political problems. On the other hand, network and wireless communication systems have birthed another modern eco- nomic and industrial revolution. New industries and economies based on communication services have sprung up from the widespread availability of information. Harnessing information continues to change the course of technological and social development [1]. In this article, the authors suggest that the landscape or history of indus- trialization is a full circle: from energy

FIGURE 1-—Visual history of industrial revolutions: from energy to services and communica- tion and back again to energy.

FIGURE S1—The Boulton and Watt double-action steam engine with rod and shaft transmission (1784). (Image courtesy of Tesla Memorial Society.) Historians define industrial revolution as an irreversible, rapid change of technology, culture, and socioeconomic con- ditions—driven by advances in industrial processes. The ongoing development of industries is also called industriali- zation. Several industrial revolutions can be identified starting around 1750, 1870, and 1950, though some historians pro- pose finer (more articulated) divisions of these revolutions into more periods.

FIGURE $2—Nikola Tesla’s plant in the Power House No. 1 at the 3-MW Niagara power station (1895). (Image courtesy of Tesla Memorial Society.) An interesting aspect of this latest industrial revolution is that the desired advances rely heavily on the highly diverse knowl- edge, training, and skills of the industrial electronics community. Control and communication techniques applied to energy con- version and transmission enable the advancement of the appli- cation of renewable energies and distributed power generation.

FIGURE 2—A possible scenario of the future power system based on smart-grid technolo- gies, with power electronic building blocks (PEBBs) and mechanical building blocks (MEBBs) as intelligent energy conversion nodes. In the next section, a possible scenario for future power systems is explored. The requirements of energy control and information flow are exam- ples of multidisciplinary cooperations A smart grid is modeled by two concentric circles—the outer circle represents energy flow and the inner circle models information flow over communication networks. Different approaches to the management of energy flow in active grids integrating distributed power generation have been proposed [11]. One of the most interesting ideas employs energy hubs to manage multiple energy car- riers (e.g., electricity, natural gas, and district heating) [12]. Within each hub

FIGURE 3—Major ICT application domains in smart grids and their correlation with grid levels. From an application perspective, there are three major domains for ICT (Figure 3). Supervisory control and data acquisition (SCADA) is already widely used for remote monitoring and controlling of higher levels of the distribution grid [17]. This area is also well covered by advanced standards such as IEC 61850 for substation auto- mation. Active distribution grids are the core of modern smart grids and enable the integration of distributed energy sources mainly into the mid- level voltage grid. The predominant task of communication in this respect is to collect critical network parame- ters and to actively influence the dis- tributed energy generation so as to maintain overall power quality. On the lower grid levels, smart metering is the most relevant use case for ICT.

FIGURE 4—Communication infrastructures for smart grids. Wireless networks are the second option. They are flexible and can be used to build utility-owned networks. However, typical broadband com- puter network technologies _ like worldwide interoperability for micro- wave access (WiMAX) and wireless local area network (WLAN) are prob- lematic with respect to their limited transmission range and reachability, especially in urban areas. Hence, they might only serve as communication subsystems for small clusters of devi- ces such as meters. For long-distance The first possibility is to use public telecommunication networks. In the recent past, provider-based communi- cation capacity for mobile services like a global system for mobile com- munication (GSM), general packet

FIGURE 5—A multiloop controller for grid interface in renewable energy applications.

FIGURE 6—Control functions of PV or wind turbine systems. TSO is the transmission system operator. Small-scale renewable generation systems for isolated, remote loca- tions are generally more expensive than traditional systems. Multiple types of sources are often employed, forming hybrid systems that are more robust than single-source systems. At the same time, hybrid systems are more complex and require some form of information exchange between ele- ments. In very small systems, the cost of centralized control and the com- munication system becomes an issue. As mentioned earlier, the relatively small size of many RESs makes it fea- sible to develop smaller-scale net- works for geographically remote or isolated areas not previously served by a traditional utility network. Com- binations of sources can be grouped together, forming a microgrid. Con- trol of the multiple sources to ensure high-quality voltage waveforms is increasingly enhanced by advances PV and wind energy are intermittent sources and produce power P that varies with environmental conditions. Current-voltage (i-v) characteristic of a PV panel is a function of irradiance

FIGURE 7—Red dots are optimal operating points for (a) hypothetical PV and (b) wind turbine characteristics.

FIGURE 9—Maximum power point tracking with open-loop control for a wind turbine system (point A represents a stable operat- ing condition; wind growth leads the sys- tem to work at B, and then at the new equilibrium point C). Variable speed operation requires some electrical mechanism to accom- modate the differences between the wind turbine’s variable speed (gener- ation side) and the fixed frequency of the electrical utility grid (demand side). A widely used commercial prac- tice is to employ some variation of induction machine along with ac—dc power converters. Differences in tur- bine speed and grid frequency mani- fest as the induction machine slip frequency. Turbine speed is con- trolled by adjusting the electrical load via the front-end nower converter FIGURE 8— Maximum power point is achieved when the derivative of power respect to the control variable is equal to zero (x=i,v,T, W).

FIGURE 10—A hybrid energy system. technology section of this paper (see section “Technology for Renewable Energy Systems’’). The concepts are also well documented in the research and commercial literature.

FIGURE 11—Power generation plants in Alabama. Blue: hydro; yellow or green: fos- sil fuel; red: nuclear. RESs are often coupled with other mechanisms to improve ride through, which refers to the capability of pro- viding energy when the prime mover (e.g., wind or sun) dies for a brief period of time. For example, batteries, flywheels, and diesel generators are several examples of mechanisms that can be linked on a common grid to wind turbine systems (see Figure 10). The resulting hybrid energy systems Present NUMETOUS Chlalenees. LaCil OF the elements is capable of operating at variable speed and power output, yet the stress and durability due to var- iable speed operation must be consid- ered. As an example, it is well known that the diesel generator does not endure frequent start/stop cycles well, yet fuel consumption from continuous operation is undesirable. Finding the proper balance of loading the various hybrid system components can be considered a constrained optimization problem. Fuzzy logic-based supervi- sory control has been applied to the problem of deciding when to store energy in the auxiliary system or to extract energy from storage.

of the ancillary services are similar to those that traditional power plants provide to ensure safe and stable sys- tem operation. However, they are mainly considered at a distribution level and are neither part of the fea- tures of an active distribution grid (smart grid) nor at the transmission level (where traditional power plants are usually connected). Moreover, when a distributed resource is low- voltage connected, the grid frequen- cy and the grid voltage cannot be controlled independently, since low- voltage distribution lines have non- negligible resistance. Hence, these issues cannot be considered as a mere transposition of known con- cepts at a different level, since they are involved in a wider change of the power system.

FIGURE 13—Comparison of ac and dc transmission systems. (a) Traditional ac transmission. (b) HVDC transmission. Electric Machines

FIGURE 16—Variable speed system employing ac machines (asynchronous or synchronous) and full-power back-to-back converters.

FIGURE 17 —Direct drive system with permanent magnet generator.

FIGURE 18—The Soltcar PS-10 solar thermal power plant near Seville, Spain (courtesy of Solticar Energia, S.A.).

FIGURE 19-Solar Stirling engine (courtesy of SES, Inc.).

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An inter-sectoral comparison of green supply chain management in China: Drivers and practices

by Joseph Sarkis

2006, Journal of Cleaner Production

The issue of green supply chain management (GSCM) has received increased attention in recent years among manufacturing practice and research. Yet, the corporate and environmental manufacturing issues in developing countries have not been... more

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Geometric error measurement and compensation of machines—An update

by Han Haitjema

2008, CIRP Annals - Manufacturing Technology

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An exploration of measures of social sustainability and their application to supply chain decisions

by Margot Hutchins

2008, Journal of Cleaner Production

Sustainability recognizes the interdependence of ecological, social, and economic systems -the three pillars of sustainability. The definition of corporate social responsibility (CSR) often advocates ethical behavior with respect to these... more

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.

Fig. 2. Portion of the category hierarchy for an environmental LCA (adapted from [21,23,24)]). MJ. Hutchins, J.W. Sutherland / Journal of Cleaner Production 16 (2008) 1688-1698

Fig. 3. Portion of category hierarchy for a social LCA. The Sustainability Reporting Guidelines were developed in conjunction with numerous stakeholders, including businesses, non-profit groups, investor organizations, and trade unions. The ef- fort was led by the United Nations Environment Programme (UNEP) and the Coalition for Environmentally Responsible Economics (CE- RES), a non-governmental organization in the United States [33]. This framework, like that of the UNDSD, organizes indicators into a four-tired hierarchy. However, the levels are termed areas (social, environmental, and economic), categories (e.g., human rights), as- pects (e.g., non-discrimination), and indicators (e.g., a description of global policy and procedures/programs preventing all forms of discrimination in operations, including monitoring systems and results of monitoring). The framework also differentiates between “core” and “additional” indicators - core indicators are those most pertinent to reporting organizations and stakeholders, other One of the fundamental questions that must be answered if we are to move forward with a life cycle assessment tool for social sustainability is: what impacts should be considered? A consensus

Fig. 4. Boundary for assessing social performance of a company.

Fig. 5. Infant mortality vs. GDP per capita, 2003 (national data as reported in [52]). Using Eq. (2), the initial infant mortality rates predicted for the U.S. and Mexico are 4.030 and 14.30, and the total number of infant deaths would be 16,675 and 31,337. For the situation described

Fig. 8. Supply chain for company A. As can be seen in Table 2, Company B3’s measure of social sus- tainability is significantly higher than that of Company B1 or B2. Therefore, in order to improve its overall social performance, Company A would elect to purchase from Company B3 opposed to B1. After making this supplier decision, Company A could then begin to explore the value-weighted impacts within its supply chain. First, the value-weighted social sustainability metric, Zo, of Company D can be calculated using Eq. (5b) by combining the social sustainability metrics shown in Table 2 and the value/cost

Fig. 7 illustrates a situation where a company purchases material or components from another organization and then performs pro- cesses that contribute additional value to an output component or product. The value-weighted social sustainability measure for the supplier is termed Z;, where Z; = S;C;. The index i is used to handle situations where there are multiple suppliers. Note that relative to Eq. (4) above, value (V) has been replaced with cost (Cj) since the cost paid to purchase the material/component from the supplier represents the value of the item to the company. As is evident from the figure, the value-weighted social sustainability for the company includes the social impact of its suppliers and the social impact of the company itself and is given mathematically by Eq. (5): Fig. 7. Value-weighted social sustainability of a company within a supply chain.

UNDSD theme/sub-theme framework for social dimension of sustainability [32] Table 1

Value-weighted social sustainability of Company A and its direct suppliers Table 4

Value-weighted social sustainability of Company D and its suppliers Table 3

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A life-cycle assessment of Portland cement manufacturing: comparing the traditional process with alternative technologies

by Deborah Huntzinger

2009, Journal of Cleaner Production

Concern over the impact of anthropogenic carbon emissions on the global climate has increased in recent years due to growth in global warming awareness. Approximately 5% of global CO 2 emissions originate from the manufacturing of cement,... more

Fig. 1. Process flow diagram for the cement manufacturing process, showing energy and heat consumption or inputs, as well as gaseous and particulate emissions (adapted from Ref. [31]). Note that emissions at the preheating and kiln stages include both fugitive emissions and cement kiln dust or those particulates captured with controlled devices. Life cycle assessment (LCA) is a method of evaluation used to assess the environmental impacts of technologies from “cradle to

Fig. 2. Scope of comparative LCA for cement manufacturing process. The dashed line signifies the boundaries of the system examined

Fig. 3. Material flow diagram for the production of 1 ton of traditional Portland cement (adapted from Rundman [28]).

Fig. 4. Life cycle network (cradle to gate) showing the allocation of environment impact for each step of the traditional Portland cement manufacturing process. The environmental impact score by impact categories for the four different cement products is shown below in Table 4. Of primary interest is the global warming potential of the traditional cement product versus the three (3) process/product alternatives. The main greenhouse gas generated from the manufacturing cement is carbon dioxide (COz). As mentioned previously approx- imately half of the carbon released during the manufacturing of cement originates from the calcining process (driving off CO2 from limestone to form clinker) and the remaining carbon results from the burning of fuels to fire the kiln and power the other manufacturing processes. Of the cement products examined, the blended cement has the lowest global warming potential followed by cement produced when a portion of the process related carbon emissions are captured back by sequestration in CKD. The recycling of CKD back into the kiln feed has little to no effect on reducing carbon emissions compared to traditional cement. The high impact scores for heavy metals and acidification are believed to be an artifact of the types of fuels selected and the incomplete representation of chemical interactions occurring in the kiln. For instance the actual sulfur dioxide emissions (a major contributor to acid rain) are much lower than those predicted in SimaPro. The clinker and CKD serve as partial scrubbers for SO2, removing a significant portion of the sulfur oxides (greater than 70%) in the combustion gases before they are released to the atmosphere [36]. Actual fugitive emissions of SO2 equal approxi- mately 0.27 and 0.54kg per ton of clinker produced [36,18], compared to the 4.86 kg estimated by SimaPro. As for heavy metals, the lead (Pb) content of the fuels selected (i.e. fuel oil) is assumed to be the source of the high heavy metal impact score. While heavy metals are released during the burning of many of the fuels typi- cally used during the manufacturing of cement, as with sulfur dioxide (SO), metals tend to concentrate in both the cement kiln dust (primarily) and clinker [36]. Since the focus of this assessment was global warming potential or greenhouse impact, corrections

Raw material composition of clinker, the primary component of Portland cement [7]. Table 1

Energy and emission inventory elements for the traditional cement manufacturing process. The energy inputs and emissions are divided among the three major pro- cessing steps.

Energy consumption by fuel type in 2000 by the United States cement industry (from Ref. [18]). kMt: thousand metric tons and ML: million liters.

Classification of process inputs and outputs for Portland cement manufacturing into environmental impact categories. for heavy metals and sulfur dioxide were not made. Such correc- tions should be included in the future for a more detailed analysis

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Severe plastic deformation (SPD) processes for metals

by Antti Korhonen

2008, CIRP Annals - Manufacturing Technology

Processes of severe plastic deformation (SPD) are defined as metal forming processes in which a very large plastic strain is imposed on a bulk process in order to make an ultra-fine grained metal. The objective of the SPD processes for... more

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Recent Advances in Mechanical Micromachining

by D. Dornfeld

2006, CIRP Annals - Manufacturing Technology

This paper reviews some of the main drivers, developments and future requirements in the field of micromanufacturing as related to the machining process from the perspective of the recent research and development literature. For the... more

Figure 1: Micromachining capability over time [2]. and where it fits relative to other microfabrication processes. Alting, et al [5] covers a broad range of fabrication techniques for small scale parts and placed microfabrication processes relative the broader field of “microengineering” and discussed the design of microproducts. This paper focuses primarily on material removal by geometrically defined cutting edges for the purpose of creation of precise three dimensional workpieces with dimensions in the range of a few tens of nanometers to some few millimeters. The motivation for increasingly smaller components parallels the improvements in cutting technology as outlined in [2]. Demand for reduced weight, reduced dimensions, higher surface quality and part accuracy, while at the same time decreasing component costs and reducing batch sizes for components of devices ranging from electro-mechanical instruments to medical devices force us along Taniguchi’s curve. These are the forces driving miniaturization. The response of the scientific community has been energetic but mixed. That is, while the development of machine tools for micromachining follows more traditional paths of scaling down conventional

Weule et al. [16] concluded that the roundness of a cutting edge is very important in micromilling due to the size effect. Since the tool edge is relatively large compared to other tool dimensions and the tool is relatively weak due to micro- tool fabrication methods, it is important to choose proper cutting parameters.

Figure 6. Lucca et al. [32] also found that the total specific energy is seen to significantly increase at small depths of cut in micromachining of OFHC copper. Hence, the specific energy is closely related to the minimum chip thickness and can be another indicator for cutting mechanism changes and process control.

Figure 8: Micromachined chips of aluminum showing folded sections in the form of a curl [44].

The aforementioned FE modeling is primarily for isotropic micromachining where no crystallographic effects were considered. Chuzhoy et al. [63, 64] developed a FE model for micromachining of heterogeneous material, Figure 11. Their model was capable of describing the microstructure of multi phase materials and thus captured the microcutting mechanism in cast iron. Microcutting of multi phase materials exerts larger variations in the resulting chip shape and the cutting force than seen in cutting of a single phase material. Figure 11: Computed equivalent stress for 125 wm depth of cut and 25 yam edge radius at t=0.00012 s with (a) ferritic workpiece, (b) ductile iron workpiece [63].

Figure 12: Actual (left column) and simulated (right column) microstructures of different ferrous materials [65].

Figure 16: Components of cutting force per unit width in round edge cutting model (friction coefficient: 0.3, rake angle: 0°, workpiece: copper (CDA110), edge radius of the tool: 0.01 sm) [90].

Figure 19: Various microgrooves and their fabrication by rotational cutting tools [111]. One of the more interesting applications of micromachining is in micropattern generation either on flat or curved surfaces. These patterns can work as reflectors, abrasives, and other functions. Traffic signs, Fresnel lenses, and possible CMP (chemical mechanical planarization) pad surfaces are typical examples. Various microgrooves can be created by feeding a rotating cutting tool along one direction relative to the workpiece, as illustrated in Figure 19 [111].

Figure 20: Various kinds of trapezoid microgrooves (first row: 20 wm, second row: 50 wm depth) [unpublished data from Y. Takeuchij]. Changing the angle and depth of groove, six different trapezoid microgrooves were created on a brass surface, as shown in Figure 20. The grooving was done with cutting conditions of 50 mm/min feed rate, 13 m/sec cutting speed, and 1 wm depth of cut for finishing and 5 wm for rough cutting. A diamond tool was used to create the trapezoidal microgrooves. With respect to these grooves, it was found that the machined surfaces are very smooth with sharp edges similar to more _ conventional V-shaped microgrooves. Trapezoidal microgrooves were successfully applied to bond two small parts without adhesives.

Figure 18: Process chain of micro-injection molding [110]. Bissacco et al. [110] investigated a wide range of processing methods for mold fabrication. Figure 18 illustrates the process chain for micro-injection molding for micro-fluidic systems. MEMS technology provides high precision processing capabilities but is very limited in achievable shapes allowing only molds in 2.5-D and those with a number of stackable layers.

Figure 17: Portion of micromilled trenches with stepped and straight walls (scale bar = 100 wm) [106]. Freidrich and Vasile [106] were able to produce trench features 8 «am wide and 62 um deep for an aspect ratio of nearly 8, over a length of 8 mm, Figure 17. This aspect ratio is good enough for most micromolding applications including X-ray masks.

Figure 22: Machined 3-focus micro-Fresnel lens [113].

Figure 27: Coordinate relationship in tool making and machining [3].

Figure 26: Principle of elliptical vibration cutting [103]. Egashira) and Masuzawa [123] conducted _ similar microdrilling tests using ultrasonic vibration but the vibration was applied to the workpiece instead of the tool. Quartz glass work material and a sintered diamond tool were used for the tests and they succeeded in drilling holes as small as 5 wm diameter.

Figure 28: Commercial 5-axis control ultraprecision machining center [132]. Furukawa et al. [130] built a machine using alumina-based ceramics for the structural members because of their high rigidity and thermal reliability and surface-restricted type aerostatic slideways to avoid friction. Takeuchi et al. [131] developed a 5-axis ultraprecision milling machine using non-friction servomechanisms for the creation of 3D microparts with translational resolution of 1 nm, rotational resolution of 0.00001 degree, and slideway straightness of about 10 nm/200mm. Figure 28 shows a commercial 5-axis ultraprecision machining center employing aerostatic guideways and coreless linear motors to provide non- contact, high resolution drive mechanisms achieving 1nm motion accuracy. To ensure thermal stability, alumina ceramics were used for structural components [132].

Figure 29: Scaling effect on tool geometry and wear (work material: 40CrMnMo/7, 50 HRC, cutting speed: V, = 200/100 m/min, depth / width of cut: a, = ae = 0.04 xd, feed: f, = 0.01 x d, number of teeth: 2, down milling, tool material: cemented carbide with TiAIN coating) [47]. Fabrication of micro-tools is another challenge in micromachining. Imprecise geometry and the irregularity of tools often negate the advantages of ultra precision process control, state of the art machine tools, and ultra fine tuning of process parameters. Figure 29 a-c shows the tool geometry deviation with respect to the size of the tool; as the tool size decreases from 2 mm to 0.2 mm, the deviation of the given tool geometry from the tool design increases. Also, scaling effects can play a significant role in process physics, which are closely related to the cutting mechanism, caused by a change in tool geometry during cutting. Figure 29 d-f demonstrate tool wear occurring during the micromilling of hardened steel as a function of the engagement length and tool diameter [47].

Figure 30: Overviews of produced micro-tools under optimum machining conditions: (a) Ultra precise tool (b) Extremely large aspect ratio micro-tool [155].

Figure 32: Micro-end milling under dry ice supply (work material: NiTi shape memory alloy, cutting speed: V, = 19 m/min, depth of cut: a, = 10 um, width of cut: a, = 10 ym, feed: f, = 20 um, micro-end mill: cemented carbide with TiAIN coating, d=400 um, nozzle distance: 80 mm, intermittent supply of dry ice) [47].

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Delay-dependent robust stability criteria for uncertain neutral systems with mixed delays

by YoNg He

2004, Systems & Control Letters

2008) Delay-dependent robust stability criteria for uncertain systems with interval time-varying delay. Journal of Computational and Applied Mathematics 214(2):pp. 480-494.

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Numerical simulation and experimental validation of vapour compression refrigeration systems. Special emphasis on CO 2 trans-critical cycles

by Gustavo Raush

2005, International Journal of Refrigeration-revue Internationale Du Froid

A numerical and experimental comparative study of a carbon dioxide trans-critical refrigerating system and a conventional sub-critical refrigerating cycle is presented. Attention is focussed not only on the whole refrigeration cycle, but... more

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Prognostics and health management of electronics

by Pradeep Lall

2000, IEEE Transactions on Components and Packaging Technologies

The current state of the art in managing system reliability is geared toward the development of predictive models for unaged pristine materials. The current state of art allows the prediction of time-to-failure for a pristine material... more

COMPONENT TEST MATRIX Fig. 1. Test board thermal cycle (—40 °C to 125 °C).

Fig. 2. Weibull plot of 1% failure for 15-mm BGA, 27-mm BGA, and C2BGA.

Solder ball elements were meshed in ANSYS with VISCO107 elements, whereas all other package materials were meshed with SOLID45 elements. Fig. 4 shows the three-dimensional (3-D) quarter symmetry finite-element models for C2LBGA. ANSYS was used to simulate the thermal cycle fatigue. The quarter symmetry model was used with in this study. This constitutive law has been used by Darveaux 3]-[7] in development of damage relationships. The constitu- tive behavior model has therefore been kept the same to enable benchmark of damage relationships. Anand’s model is split into a flow equation and three evolution equations that describe the strain hardening or softening of the materials (Table II).

Fig. 3. Typical selected region for bulk solder phase growth measurement, 27-mm BGA (Sn63/Pb37 solder).

Fig. 4. Three-dimensional quarter symmetry finite-element mesh for C2BGA assembly.

Fig. 7. SEM backscattered images of phase growth versus thermal cycling (—40 °C to 125 °C, Sn63/Pb37 solder).

Fig. 12. Relation between number of cycles to 1% failure and phase growth rate. Fig. 11. Crack propagation data for 15-mm BGA, 27-mm BGA, and 16-mm C2BGA.

Fig. 8. Correlation of incipient crack growth with phase growth in BGA packages (Sn63/Pb37).

Fig. 10. Simultaneous crack propagation top and bottom of the solder joint, C2BGA. Fig. 9. Phase growth parameter, at various levels of cycles for 15-mm BGA, 27-mm BGA, and 1225 chip resistor.

Fig. 15. Optimized eight-element rosette on (111) silicon.

Fig. 16. C200 flip chip test die (5 x 5 mm).

Fig. 17. Photograph of FC200 sensor rosette.

Fig. 18. Interfacial shear stress drops before the appearance of delamination (C-SAM)

Fig. 19. Die stress variation at the nondelaminated location of the die where stress values are gradually decreasing because underfill materials are loosing adhesion due to thermal cycling (C-SAM).

Fig. 20. Die stress variation at the delaminated location of the die where stress values are initially increasing before starting the delamination because underfill materials properties are changing due to thermal cycling (C-SAM).

Fig. 21. Stress variation at the nondelaminated location of the die where stress values are gradually decreasing because underfill materials are losing adhesion due to thermal cycling.

Fig. 22. Die stress variation at the delaminated location of the die where stress values are initially increasing before starting the delamination because underfill materials properties are changing due to thermal cycling (C-SAM).

VALUES OF ANAND CONSTANTS USED FOR SIMULATION were used for the study. The boards were placed vertically in the chamber, and the wiring passed through access ports to the data acquisition system. Monitoring of the various daisy-chain networks was performed throughout the cycling using a high accuracy digital multimeter coupled with a high performance switching system controlled by LabView software. Failure of a daisy-chain network was defined as the point when the re- sistance change became 10 2) or higher. Typical thermocouple results from under a component on one of the test boards are illustrated in Fig. 1. The resulting failure data were statistically analyzed using two parameter Weibull models. The Weibull reliability data plot for the metal-backed BGA components is shown in Fig. 2.

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Grid-Connected Photovoltaic Systems: An Overview of Recent Research and Emerging PV Converter Technology

by Leopoldo G Franquelo and

2015, IEEE Industrial Electronics Magazine

Photovoltaic energy has grown at an average annual rate of 60% in the last 5 years and has surpassed 1/3 of the cumulative wind energy installed capacity, and is quickly becoming an important part of the energy mix in some regions and... more

progress is that the PV converter market demanded very hard-to-meet specifications, among them: high efficiency (above 98%), long warranty periods (to get closer to PV module warranties of 25 years), high power quality, transformer-less operation, leakage current minimization (imposes restrictions on the topology or modulation), special control requirements such as the MPPT, etc. Another driver behind this development is control requirements such as the MPPT, etc. Another driver behind this development is the fact that, for long time, the power converter represented a small fraction of the cost of the whole PV system, due to high PV module prices, allowing PV inverter manufacturers room for development of higher performance and more sophisticated topologies, which usually included more power electronics devices than classic

2) Power Density: This feature is always important but it is becoming critical mainly for is due to the cost of the PV modules. The inverter cost has been reduced by a 68%, and

Table II. Grid-connected photovoltaic energy conversion systems configurations overview

Fig. 3. Industrial photovoltaic inverter topologies for central, string, multi-string and ac-module configurations

rectifying diodes and improved light-load behavior. Fig. 5. New emerged topologies of the PV module integrated DC-DC converters.

Table V. Commercial power semiconductor modules for grid-connected PV inverters FXO AIL ANCITGAUVG TUL SCHIUUIL UGSVIUGS, WIG UVot UE WIG VV DY UCVIUGS TIUot UG LANGTT HU account, silicon industry takes advantage of 60 years (the first silicon bipolar transistor was presented in 1954) of expertise, and consequently the production processes are very mature and well optimized. On the other hand, the new processes are still far from maturity, as they are in their first steps, being a very promising technology, as no doubt, the cost reductions will come gradually. It is important to highlight that the extra cost of the devices may be compensated by important reductions in costs related to passive reactive components and heat management, of course for critical applications the reduction of size and the increase of performances can make these devices very the devices may be compensated by important reductions in costs related to passive

Table III. Summary of characteristics and examples of selected industrial photovoltaic inverter topologies V. RECENT ADVANCES ON GRID-CONNECTED PV INVERTERS

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Stable Haptic Interaction with Virtual Environments Using an Adapted Voxmap-PointShell Algorithm

by Matthias Renz

2001

keeps an unsolved problem. Among different approaches the Voxmap-PointShell TM (VPS) method seems very promising due to constant sample rates, independent of the static environment. But there is still the stability problem to be solved... more

EE EEE IEEE EE. EE EEE IES IEEE EE EE In this experiment the sphere slides on a circle path around the superficies surface of a cylinder, with also a constant penetration depth into the cylinder (Fig. 10). This shows the collision force distraction behavior with many different surface condition cases. Figure 9 a) shows the distractions of the collision force over the time calculated with the original algorithm and Figure 9 b) shows the distractions with the adapted algorithm. Of cause there are still remaining distractions with the adapted form coming from the different surface conditions, but a high reduction of these distractions can be seen with the adapted collision force calculation.

The haptic rendering update rate 1s Independent trom the complexity of the static environment, thus qualifying for real time applications. The environment of static objects is collectively represented by a single spatial occupancy map called a voxmap (volume map). This is created by discretizing the static environment space, which is partitioned into regions of free space, object surface, and object interior. The col ection of the discrete volume elements (voxels) build the voxmap. The dynamic object is described by a collection of points (PointShell), which models its surface. Each point normal vector, pointing inwards. algorithm includes a fast collision based on probing the voxmap wi samples of the PointShell. By using the PointShell, an approximate co easily computed in constant time interpenetration. Figure 1 shows a with the voxmap. For each PointShe is assigned a surface The haptic rendering detection technique th the surface point the normal vectors of lision force can be for each point-voxel PointShell colliding 1 point, contained by a surface voxel, the depth of interpenetration is calculated as the distance d from the point to the tangent plane. This plane passes through the voxel cen ter and has the same normal vector as the PointShell point normal vector.

‘igure 2: Different collision force effects in comparison between the original PointShell and our exact Point Shell of e/2. In the case of Figure 2 a) the PointShell was created using the voxel raster shown with dashed lines. With this rough surface approximation only one of the four PointShell points effects a collision force, although the ‘real’ dynamic object surface cross three force layer voxel. Figure 2 b) shows the effected collision forces using the exact PointShell model, creating a smoother force field.

The exact PointShell creation process steps are shown in Figure 3. The first two steps are equal to the original PointShell creation. In order to guarantee a proper detection of collisions between dynamic and static objects, the distance between two neighbored PointShel points is limited according to the voxel resolution of the static environment. Hence the ‘naive’ PointShell is built by the sum of all center points of the resulting surface voxels, after creating the VoxMap of the dynamic object with the same resolution as of the static environment (Fig. 3, 1-3).

2.2 Adapted Collision Force Calculation For each original PointShell point (voxel center), map it on the corresponding triangles, and choose the result point with the shortest distance to the voxel center. The set of all mapped points build the exact PointShell. Now the PointShell vectors can be calculated from the normal directions of the triangles intersecting the relevant voxel.

sliding over a plane of adjacent surface voxels. When force value is reduced overall collision force. average of all collision the interpenetration dis approximation of the mentioned problem can to zero, which in Instead of using the individua PointShell normals to calculate the collision force, the PointShell points cross the border between these adjacent voxels, instability occurs if the direction of the relevant point normal vector is not perpendicular to the sliding plane. Figure 5 a) shows a dynamic object colliding with a static object under sliding motion. Figure 5 b) and c demonstrate the interesting area (marked with the dashed ine in 5 a)). Figure 5 b) shows the problem with the original force calculation method PointShell point crosses the voxel border, the calculated that appears . When the fluences the point normals is used be mitigated. to calculate tance d of each PointShell point Figure 5 c)). This average direction is a more stable sliding plane normal, and the The schemes described above only reduce force noise, but there are still remaining distracting forces causing an unstable system. The direct way to reach the required stability is to use a ‘virtual coupling’ scheme between the operator and the virtual environment. A design framework for the virtual coupling is presented, that allows a consistent interaction between the haptic rendering (VPS) and different haptic devices, because for the overall stability, the dynamic properties of the haptic device play a key role.

© SFR ASA ee MASE FR aR AES NES REACT Oa a a a a RiNimnes Snes ena The virtual coupling can also be seen as a a dynamic shaping filter, as it is done in this approach (Fig. 6). The dynamics of the calculated contact force are reduced such that neither the haptic device nor the force reflection loop with the human become unstable. The filter should keep the role of the virtual coupling, thus the physically model of the virtual coupling (the spring-damper system) is used as a model for the construction part.

Figure 12: Force plots of the experiments with the Phantom and the LWR In Figure 11 shows the results of a heuristic tuned virtual coupling and the dynamic shaping filter explained in chapter 3. In hardware-in-the-loop experiments, the virtual cup (Fig. 15) was touched by the virtual sphere using the DLR Light-Weight robot (LWR) (Fig. 13) and the Phantom T-Model (Fig. 14) as haptic hand controllers. The following diagrams (Fig. 12) shows the collision forces (thin line) calculated by the haptic rendering algorithm and the corresponding output force (thick line), which was returned as feedback force to the hand controllers by the virtual coupling element. Two kinds of collisions were tested, an abrupt collision, hitting the cup with the sphere (Fig. 12 ac), and a steady collision, sliding with the sphere over the cup surface (Fig. 12 b,d).

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A review of piezoelectric energy harvesting based on vibration

by Jaehwan Kim

2011, International Journal of Precision Engineering and Manufacturing

This paper reviews energy harvesting technology from mechanical vibration. Recent advances on ultralow power portable electronic devices and wireless sensor network require limitless battery life for better performance. People searched... more

Fig. 1 Comparison of the energy density for the three types of . s 9 mechanical to electrical energy converters

Fig. 4 A two-layer bender mounted as a cantilever'*

Fig. 5 Conventional piezoelectric energy harvesters external vibrational energy source can create electrical energy via the piezoelectric effect. The effect of proof mass, beam shape and damping on the power generating performance were modeled to provide guideline for maximum power harvesting from environmentally available low frequency vibrations.

Fig. 6 Model of a vibrating structure including a piezoelectric 26 element

Fig. 7 Curved PZT unimorph excited in d31-mode by a normal distributed force’

Fig. 8 Geometry and position of the neutral axis of PCGE-A> conventional piezoceramic processing methods corresponding to high energy density piezoelectric composition 0.9Pb(Zr0.56 Ti0.44)03-0.1Pb[(Zn0.8/3 Ni0.2/3)Nb2/3]03 +2 mol% MnO2 (PZTZNN) and 0.8[Pb(Zr0.52Ti0.48)03]-0.2[Pb(Zn1/3 Nb2/3)03] (PZTPZN). They concluded that power harvesting largely depended upon piezoelectric strain constant and the piezoelectric voltage constant.

Fig. 11 (a) Schematic view, (b) general FE-SEM image, and (c) lateral FE-SEM image of A1N microgenerator™ Fig. 10 Schematic of the backpack with piezoelectric straps”

Fig. 9 A piezoelectric film-based power generator”

Fig. 12 Energy conversion efficiency of a piezoelectric PVDF 72 nanogenerator

Fig. 13 A prototype tree-shaped wind power system’ found that it increased with increasing strain, which was favorable for vibration energy harvesting.

Fig. 16 (a) Full wave-bridge type rectifying circuit for vibrational piezoelectric energy harvester, (b) Synchronous charge extraction circuit with an inductor L and a switch S$7°

Fig. 15 A schematic diagram of the piezoelectric generator in a flow field and the concept of placing an elastic beam into the . * A 80 vortex street to induce vibration Fig. 14 Motion sketch of two different structures”

Fig. 18 Rectifier-free piezoelectric energy harvesting circuit”

Fig. 19 Two stage rectifying circuit for ultra low input piezoelectric voltage”!

4.2 Circuits and storages collect electrical energy and summarized governing equations for

Table 1 Piezoelectric characteristics” Direct piezoelectric effect:

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