Manufacturing Engineering

Several researchers have stressed the need for a proper implant-patient match in hip joint replacements, in particular, for cementless femoral stems. Some of the complications of mismatch are aseptic loosening, improper load distribution, and discomfort. In this study, the differences in dimensions between femurs of elderly Indians and those of populations from other regions are compared in order to solve the problem of a possible geometric mismatch between a selected implant and the femurs of an Indian patients are concerned. This paper also describes a methodology for implant designing from measured anthropometric data, fit evaluation, finite element (FE) stress analysis and subsequently implant manufacturing using the CAM (Computer Aided Manufacturing) technique. The machining of the Titanium alloy femoral stem is usually performed on a 5 Axis CNC (Computer Numerical Control) machining center. However, in this study the machining of the femoral stem was effectively performed on a 3 Axis CNC machining center to emphasize on economical benefits for low cost manufacturing strategy.

Population centres in low atoll islands have water supply problems that are amongst the most critical in the world. Fresh groundwater, the major source of water in many atolls, is extremely vulnerable to natural processes and human activities. Storm surges and over-extractions cause seawater intrusion, while human settlements and agriculture can pollute shallow groundwaters. Limited land areas restrict freshwater quantities, particularly in frequent ENSO-related droughts. Demand for freshwater is increasing and availability is extremely limited. At the core of many groundwater management problems are the traditional water ownership rights inherent in land tenure and the conflict between the requirements of urbanised societies and the traditional values and rights of subsistence communities living on groundwater reserves. Resource limitations and geographic isolation restrict the potential for increasing wealth through crop exports. Water governance reforms and the provision of knowledge to communities are critical. Regional water organisations, fostering self-support, are a key to developing island-adopted and owned solutions.

The purpose of this research was to design and develop hydrogels by esterification of polyvinyl alcohol (PVA) with gelatin. The membranes were characterized by Fourier Transform Infrared (FTIR) spectroscopy, x-ray diffraction (XRD), and differential scanning calorimetry. The viscosity of the esterified product (as solution) was compared with the mixture of PVA and gelatin of the same composition. The mechanical properties of the hydrogels were characterized by tensile tests. Swelling behavior and hemocompatibility of the membrane were also evaluated. The diffusion coefficient of salicylic acid (SA), when the receptor compartment contained Ringer's solution, through the membrane was determined. SA was used as a model drug. FTIR spectra of the membranes indicated complete esterification of the free carboxylic groups of gelatin. XRD studies indicated that the crystallinity of the membranes was mainly due to gelatin. The comparison of viscosity indicated an increase in segment density within the molecular coil. The membrane had sufficient strength and water-holding capacity. Hemocompatibility suggested that the hydrogel could be tried as wound dressing and as an implantable drug delivery system. The diffusion coefficient of SA through the membrane was found to be 1.32 × 10 -5 cm 2 /s. The experimental results indicated that the hydrogel could be tried for various biomedical applications.

Many web handling processes involve nips through which the web passes. Due to contact deformations, the speed at which the nip cylinders feed the web may differ from the peripheral speed of the cylinders. This paper examines in detail the feeding phenomenon in the case of layered cylinders. In particular, we focus on offset printing cylinders which are covered by a thin rubbery layer. We begin our analysis by considering existing limiting solutions of thin layered cylinders undergoing small strains, and thereafter study the large deformation rolling contact problem using the finite element method. It turns out that the feeding tendency of layered cylinders is dominated by the compressibility of the layer. However, feeding characteristics of layered cylinders are not constant but rather depend on the applied indentation: an increase in indentation may even alter the feeding tendency of the cylinders. The results also indicate that the feeding type affects web strain. Consequently, we conclude that in order to attain better web handling, the feeding characteristics of the cylinders should be known.

T he paper describes the development of an autoresonant system with supervisory computer control, which was successfully used for the control of piezoelectric transducer during ultrasonically assisted turning. T his permits an intensive supply of ultrasonic energy into the machining zone in conditions of variable cutting loads. T he effect is achieved through the generation and maintenance of the nonlinear resonant mode of vibration and by active matching of the oscillating system with the dynamic loads imposed by the cutting process. T he system has been developed as combined analogâ€"digital, where analog devices process the control signal, and the parameters of the devices are controlled digitally by computer. T he supervisory control provides the most efficient excitation of the vibrating system and keeps the stable level of vibration under the application of the dynamic cutting loads.

In the present, the technology related to the micro/meso manufacturing is promising as a key enabling technology for maximizing high value manufacturing. This paper addresses a new methodology to design reconfigurable micro/mesoscale CNC machine tools in the integrated product, process, and manufacturing system development context. This is followed by a description of the design of a reconfigurable two-axis first-generation test bed CNC micromachine tool that was developed to assess the feasibility of the new design method. The test bed utilizes a high-speed miniature spindle that is required to obtain appropriate cutting velocities for the efficient cutting of metals, use micro-actuators for the axis movements and open-architecture controllers, in order to guarantee the reconfigurability properties of the micromachine. Results indicate the new methodology enhances the design of reconfigurable micro/mesoscale CNC machine tools in the integrated product, process, and manufacturing sy...

This paper describes how Enterprise Integration Engineering (EIE) and Action-Research (A-R) can be used to support the implementation of Product Lifecycle Management (PLM) tools. The EIE concept is used to align the corporate strategies with the use of PLM technologies in order to impact the Key Performance Indicators (KPIs) in the enterprise. An EIE reference framework is proposed to define strategies, evaluate performance measures, design/re-design processes and establish the enabling tools and technologies to support the enterprise strategies, while A-R is proposed to guide the PLM tools implementation at various stages of the product development process. An industrial application is described to demonstrate the benefits of applying EIE, A-R and PLM in an enterprise.

Due to the increasing amount of collaborative work in engineering, it is now necessary to create environments that foster the coordination and cooperation among engineering groups. The aim of this paper is to present a methodology to design and integrate 'Collaborative Engineering Environments' supported by tools that enable cooperative work and intellectual capital sharing. The resulting methodology to create 'Collaborative Engineering Environments' was developed and refined through a set of action research cycles applied to three case studies. The experiences and reflections of every case are described to contribute to a better understanding of how collaborative environments should be built up.

Silicone rubbers are promising materials that have extensively been used in many areas, including wearable electronic devices, actuator materials in soft robotics, and energy harvesters. Ecoflex, a commercially available polymer, is a group of silicone rubbers appearing with various Shore hardnesses that has become popular in recent years. While silicone rubbers in their real applications are subjected to repeated loadingunloading conditions, their mechanical behaviour under cyclic loading in different deformation modes and the corresponding stress recovery behaviour are yet to be well investigated. In this contribution, we conduct loading-unloading cyclic experiments in different time gaps between the first cycle and the second cycle to demonstrate the stress recovery behaviour after stress softening happens during the first cycle. For that, three different modes of deformations, i.e., uniaxial tension, planar tension, and equibiaxial tension tests are selected. Besides, Shore hardness dependence with different strain levels is also taken into consideration. The results show that the stress softening could recover significantly with time. These findings will help to understand the mechanical behaviour of Ecoflex silicone rubbers before selecting them in practical applications that are exposed to repeated loading-unloading cycles.

Silicone rubbers are promising materials that have extensively been used in many areas, including wearable electronic devices, actuator materials in soft robotics, and energy harvesters. Ecoflex, a commercially available polymer, is a group of silicone rubbers appearing with various Shore hardnesses that has become popular in recent years. While silicone rubbers in their real applications are subjected to repeated loadingunloading conditions, their mechanical behaviour under cyclic loading in different deformation modes and the corresponding stress recovery behaviour are yet to be well investigated. In this contribution, we conduct loading-unloading cyclic experiments in different time gaps between the first cycle and the second cycle to demonstrate the stress recovery behaviour after stress softening happens during the first cycle. For that, three different modes of deformations, i.e., uniaxial tension, planar tension, and equibiaxial tension tests are selected. Besides, Shore hardness dependence with different strain levels is also taken into consideration. The results show that the stress softening could recover significantly with time. These findings will help to understand the mechanical behaviour of Ecoflex silicone rubbers before selecting them in practical applications that are exposed to repeated loading-unloading cycles.

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Open-ended learning is a core research field of machine learning and robotics aiming to build learning machines and robots able to autonomously acquire knowledge and skills and to reuse them to solve novel tasks. The multiple challenges posed by open-ended learning have been operationalized in the robotic competition REAL 2020. This requires a simulated camera-arm-gripper robot to (a) autonomously learn to interact with objects during an intrinsic phase where it can learn how to move objects and then (b) during an extrinsic phase, to re-use the acquired knowledge to accomplish externally given goals requiring the robot to move objects to specific locations unknown during the intrinsic phase. Here we present a 'baseline architecture' for solving the challenge, provided as baseline model for REAL 2020. Few models have all the functionalities needed to solve the REAL 2020 benchmark and none has been tested with it yet. The architecture we propose is formed by three components: ...

By visualizing and engaging with the problem where many students struggle, mechanical engineering principles like Heat Transfer and FEM are better comprehended. Participating in design and development problems at the student level is one such approach that aids the students in picturizing, comprehending, and understanding the concepts. Students participate in a variety of racing competitions, such as the creation of the Quad Bike, Baja Buggy, Formula Student, etc. The students can create teams, build, and develop cars, compete against other teams nationally and globally, and more by taking part in these tournaments. Additionally, it improves the student's capacity for teamwork, empowers them to take on mission-driven projects, and develops their managerial and leadership abilities. Students improve their ability to comprehend, visualize a variety of engineering ideas during the process

Институт сверхтвердых материалов им. В. Н. Бакуля НАН Украины, г. Киев Рассчитано распределение температурных полей в ростовой ячейке с целью определения температуры на деталях сборки и возможности достижения температуры для создания условий, обеспечивающих зародышеобразование алмаза в системах на основе магния. Ключевые слова: монокристаллы алмаза, ячейка высокого давления, системы на основе магния, распределение температур.

In the past decades, the automotive industry is growing proportionally with the rapid population increase. On the other hand, increasing energy consumption and the use of fossil fuels have led to increased environmental pollution. A new trend in the automotive industry in the last twenty years is the development of new types of vehicles that are powered by renewable energy and the solar-powered vehicle is very popular among them. Solar photovoltaic technologies are very convenient for electric and hybrid vehicles, due to the direct conversion of solar energy to electricity, the low cost of photovoltaic panels, and their positive environmental impact. There are various types of solar cars developed by different companies, which have remarkable development in terms of materials, energy management systems, and used mechanical and electrical components. This paper represents an overview of solar energy applications in the automotive industry and the development of solar and hybrid cars. Also, a comparative analysis of different solar vehicles is presented, with the possibilities for further investigation and development of solar energy applications in the automotive industry.

The paper focuses on the use of naphthenic acid as a low cost ion exchanger for removing heavy metal ions from aqueous solutions. Extraction of Cu ++ from dilute aqueous solutions by naphthenic acid dissolved in kerosene in a simple jet loop reactor was studied. Variables studied were; circulation velocity, initial Cu ++ concentration, nozzle diameter and nozzle height (the vertical distance between nozzle and the surface of the liquid in the reactor). An increase in the rate of extraction was observed with increasing nozzle diameter and circulation velocity. Increasing initial metal ion concentration and the nozzle height was found to decrease the rate of extraction. The rate of extraction was expressed in terms of the volumetric mass transfer coefficient (kA), the data were correlated by the dimensionless equation: The possibility of using the present reactor for removing heavy metals such as removal of copper from printed circuit etching solution, pickling solutions, electroplating and electroless plating rinse solution and copper mines drainage solutions was highlighted.

Highly boron doped diamond (BDD) surface was grafted with 4-benzoylphenyl (BP), a photopolymerization initiator group, to provide a platform for surface-confined radical photopolymerization of 2-hydroxyethyl methacrylate (HEMA). The PHEMA-modified BDD hybrid (BDD-PHEMA) resisted non-specific adsorption while the imidazole-functionalized PHEMA graft readily reacted with BSA to provide a bioactive BDD substrate. After incubation of BDD-PHEMA-BSA in anti-BSA and anti-myoglobin solution, it was found that BDD-PHEMA-BSA selectively retained anti-BSA. This work paves the way to fabrication of bioactive BDD layers through a simple process combining the surface chemistry of aryl diazonium salts and photopolymerization.

A p-type diamond Schottky barrier diode (SBD) on homoepitaxial CVD diamond is presented. The technologic steps required to carry out the experimental device are described in this paper. The B-acceptors concentration and the barrier height have been extracted from C-V measurements leading to Ns ∼ 1.2× 10 17 cm -3 and Φ Β =1.8 eV respectively. The current-voltage experimental measurements performed at room temperature have shown high current density in the range of 900 A/cm 2 . However, the breakdown voltage of the device was limited to 25 V, this low reverse value suggest the presence of a large defect density in the bulk.

We report on electromagnetic simulations of an industrial thin film deposition process for hydrogenated amorphous carbon using microwave plasmas. This process is designed to deposit a barrier coating on the inside of a PET bottle. This process relies on a resonant cavity coupled to a lateral waveguide. This cavity excites an acetylene plasma inside the PET bottle for a duration of 1 to 3 s. We aim to show the influence of the geometry and dielectric content of the reactor on the frequency and electric field structure of the resonant cavity modes. We also investigate how these modes vary as a function of the different process parameters. The calculations are validated by microwave measurements using a vectorial network analyzer. This microwave engineering approach allows us to efficiently optimise the process parameters and the final geometry of the cavity as a first step towards obtaining a uniform coating on the inside walls of a PET bottle.

Ion beam etching at grazing incidence angle has been used to reduce the surface roughness of polycrystalline diamond thin films, 1 _tO.2 pm thick, deposited by microwave plasma chemical vapor deposition (MWPCVD). Different reactive etching conditions have been tested for a beam energy of 1 keV with various ion beam and gas atmosphere compositions: pure At-', mixture of Ar+ + Nz' and Arf under a controlled oxygen partial pressure. Their influence on the etching kinetics, roughness and morphology evolutions of the film, crystalline quality have been studied using SEM, AFM and Raman spectroscopy. The optical transmittance has also been measured. The ion beam processes studied result in a drastic reduction of the film surface roughness with a slightly better efficiency for the Ar+ +oxygen gas mixture. The roughness decrease leads to an increase in the optical transmittance without any change in the crystalline quality of the film. This planarizing method should be particularly welladapted for thicker films taking into account the balance between the initial values of thickness and roughness on the one hand, and the material loss on the other. Furthermore, it could be usefully applied to produce large-area membranes.

Depleting petroleum reserves on the earth and increasing concerns about the environment leads to the question for fuels which are eco-friendly safer for human beings. The objective of present work was to investigate the effect of coating on piston, cylinder head and valves of a Diesel engine on the performance and emission characteristics of exhaust gases using wet ethanol (5% water) as a fuel. Approach: In this study the effect of Zirconia coating on the performance and emission characteristics of diesel engine was investigated using ethanol as sole fuel. For this purpose the cylinder head, valve and piston of the test engine were coated with a partially stabilized Zirconia of 0.5 mm thick by the plasma spray coating method. . For comparing the performance of the engine with coated components with the base engine, readings were taken before and after coating. To make the diesel engine to work with ethanol a modification was done. Results: The engine's performance was studied for both wet ethanol and diesel with and without Zirconia coating. Also the emissions values are recorded to study the engine's behavior on emissions. Satisfactory performance was obtained with Zirconia coating compared with a standard diesel engine. The brake thermal efficiency was increased up to 1.64% for ethanol with coating and there was a significant reduction in the specific fuel consumption. The NOx, CO and HC emissions in the engine exhaust decreases with coating. Conclusion: Using ethanol as sole fuel for a LHR diesel engine causes an improvement in the performance characteristics and significant reduction in exhaust emissions.

This article uses case studies to demonstrate the potential of smart manufacturing (SM) and Internet of Things (IoT) technologies to enhance operational performance and productivity in industry. The analysis highlights benefits such as cost reduction, production flexibility, shorter product time‐to‐market, energy/water efficiency and environmental impact reduction, and increased productivity. To illustrate the effectiveness of SM and IoT approaches, the authors sought out manufacturers currently implementing or seeking to implement SM and IoT technologies. The authors identified beer brewing (NAICS Code 312120) as a rapidly expanding industry whose members appear eager to implement SM technologies to optimize production lines by revealing bottlenecks and identifying performance‐reducing nodes. This article presents two case studies based on SM and IoT technologies in breweries. It briefly describes a systematic framework introduced elsewhere by the authors and uses it to assess the ...

Currently, the development of information technology in all fields is very rapid, including in the manufacturing sector, thus making the social environment of manufacturing change a lot. Traditional manufacturing research focuses on applying technology, such as production models, supplier arrangements, automation, advanced machines in the manufacturing industry, etc. Global competition and increasingly diverse customer demands are a phenomenon that occurs today. Social manufacturing is a new distributed, collaborative, and intelligent manufacturing, that every consumer can participate in the entire process of product design, manufacture, and even marketing. This study aims to examine the development of social manufacturing systems and the latest research in social manufacturing. The method used is to review the latest papers related to social manufacturing that provide a new paradigm for the manufacturing industry, then map based on the concepts, frameworks, and technologies used. The results of this review paper are in the form of mapping research papers taken from the database of a reputable international journal, Scopus. The mapping includes data on the author, co-author, terms on social manufacturing paper, year of publication, type of document and publisher. This systematic literature review can be one of the references for basic research on social manufacturing.

Currently, the development of information technology in all fields is very rapid, including in the manufacturing sector, thus making the social environment of manufacturing change a lot. Traditional manufacturing research focuses on applying technology, such as production models, supplier arrangements, automation, advanced machines in the manufacturing industry, etc. Global competition and increasingly diverse customer demands are a phenomenon that occurs today. Social manufacturing is a new distributed, collaborative, and intelligent manufacturing, that every consumer can participate in the entire process of product design, manufacture, and even marketing. This study aims to examine the development of social manufacturing systems and the latest research in social manufacturing. The method used is to review the latest papers related to social manufacturing that provide a new paradigm for the manufacturing industry, then map based on the concepts, frameworks, and technologies used. T...

Off-grid communities face significant challenges in achieving reliable and sustainable energy access. This paper proposes a novel hybrid energy system consisting of solar power, wind energy, and energy storage, optimized using artificial intelligence (AI) techniques. The aim is to enhance energy generation efficiency, improve system reliability, and minimize operational costs. We present a detailed analysis of AI-driven optimization algorithms that forecast energy generation, balance storage capacities, and manage energy consumption in real time. Through simulations, the proposed system is evaluated under various environmental conditions, demonstrating its potential to provide a stable, cost-effective energy solution for off-grid areas. Additionally, the study assesses the economic and environmental benefits of integrating renewable energy and advanced storage systems, showing a significant reduction in fossil fuel dependency. The results indicate that AI-optimized hybrid systems can offer an efficient and sustainable alternative to conventional energy solutions, contributing to the global transition to renewable energy.

Due to a current trend of increasing rotational speed and power, the problem of tone noise and pressure pulsation in centrifugal ventilators becomes a more urgent issue. Often the level of tones determines noise characteristics; mainly these are at blade-passing frequencies (BPF). The broadband noise resulting from small-scale turbulent pressure pulsation and secondary flows is an important problem as well. Numerical studies of pressure pulsation in ventilators are undertaken using the method based on a representation of compressible medium non-stationary motion as a combination of acoustic and vortex modes. Comparisons of results on an air pump unit show good agreement between computation and experimental data within 2 -3 dB in the total amplitude and first BPF harmonics.

An improved source-path-receiver model of a single mesh geared system is developed and validated to quantify the effect of sliding friction between gear teeth on the structure-borne whine noise. The source sub-system of a spur gear pair predicts interfacial bearing forces in the line-of-action and off line-of-action directions for two whine excitations (static transmission error and sliding friction). Next, a finite element model of the gearbox with embedded bearing stiffness matrices is developed to characterize the structural paths and to calculate the surface velocity distributions. Predictions are first validated by comparing with structural modal tests and transfer function measurements from gear mesh to the housing plates. Radiated noise is then estimated by using two approximate methods, namely the Rayleigh integral method and a substitute source technique. The overall vibro-acoustic model is validated by comparing radiated sound pressure calculations with measured noise data over a range of operating torques. The proposed formulation provides an efficient analytical and computational tool to quantify the relative contribution of sliding friction to the structure-borne noise, which is found to be significant when the transmission error is minimized say via tooth modifications.

This paper aims to present an application of the technique of rapid prototyping (RP). RP process has its own advantages and disadvantages. These techniques allow designers to produce tangible prototypes of their designs quickly, rather than just two-dimensional picture. For small series and complex parts, these techniques are often the best manufacturing processes available. This paper presents the theoretical manufacturing of mold cavities using a particularly case off RP techniques, the subtractive process and the steps that must be followed in order to obtain the products. Subtractive Rapid Prototyping (SRP) is a process who transforms 3-D digital models content into physical objects. The paper also presents particularizes the methodology to obtain a die which has applications in microinjection molding process. To realize the die it was used the algorithm of RP process: conception and designing of die in CAD the FEM simulation of the part G-code generated program in CAD software ...

Three main factors can be identified as driving forces of this rationalisation. The increasing number and functional importance of parts allotted to second tier suppliers, and therefore the increasing impact of these parts on quality, as well as on prices of the components first tier companies supply to car manufacturers. Two different processes foster this trend : major European firms in the sector, such as Valeo, Bosch, Lucas Varity, Magneti Marelli, besides sister associations operating at a national level, such as ANFIA in Italy and FIEV in France.

In the present paper, we design a die for the extrusion of a material Al6061, based on the maximum stress that is generated during the extrusion operation. We get the ideal shape of the die with which it will work, calculating the maximum force required for extrusion, this force is obtained with the stresses generated in the wall of the die. Then we analyze with the finite element software ANSYS and compared the results of two ways with the allowable stress of the material given, a system that can withstand the stresses generated in this process is obtained.

The application of conventional TIG-welding procedure is not able to answer in full to the needs of modern market from the aspect of productivity and economy. Using the emergence activation of oxidation-reduction processes in zone of welding by surface -active and electronegative elements (ATIG-procedure) the technological caracterisctics of electric arc become better. By introducing of microquantities of easy ionizing elements into a welding zone, there are making conditions for a control and operating of technological charateristics of electrical arc at welding. Under influence of plasma flow and components of activating melting material conditions of seam metal crystallization are imroved. Seam forming with tiny crystal desoriented prime structure increases resistance to warm crack forming. At work are presented research metallographyc results of welded joints with ATIG-process of welding carbon structural steel Ct.20 (GОSТ 1050-74).

The application of conventional TIG-welding procedure is not able to answer in full to the needs of modern market from the aspect of productivity and economy. Using the emergence activation of oxidation-reduction processes in zone of welding by surface – active and electronegative elements (ATIG-procedure) the technological caracterisctics of electric arc become better. By introducing of microquantities of easy ionizing elements into a welding zone, there are making conditions for a control and operating of technological charateristics of electrical arc at welding. Under influence of plasma flow and components of activating melting material conditions of seam metal crystallization are imroved. Seam forming with tiny crystal desoriented prime structure increases resistance to warm crack forming. At work are presented research metallographyc results of welded joints with ATIG-process of welding carbon structural steel Ct.20 (GОSТ 1050-74).

Climate change phenomenal is a trend that impacts the local communities by affecting their way of life. High demand for wood products to meet the demand of energy supply in Maasai-Mau region has seen the depletion of the forest cover thus increasing carbon dioxide emission and other greenhouse gases into the atmosphere. However, there is no extensive research on the benefits of alternative sources of energy like solar, biogas and biomass briquette in mitigating these impacts. The study investigated the adoption of biomass briquettes as an alternative source of energy in Maasai-Mau, Narok County, Kenya. The study was guided with three objectives (i) to determine the level of adoption of biomass briquette in Maasai-Mau region, (ii) to evaluate the challenges and hindrances Maasai-Mau residents face in the adoption of biomass briquettes in Maasai-Mau region and (iii) to investigate the availability of biomass briquette making materials in Maasai-Mau region. The study used two sampling techniques; systematic and purposive sampling to get information from the key informants and households in the study area with a target sample of 100 respondents. The findings obtained were analysed through Excel and Statistical Package of Social Sciences. Data results were presented in graphs, pie-charts, and tables. From the results, the hypothesis was analysed by Chi-square (2). The study failed to reject the null hypothesis of a relatively low level of education hinders the adoption of biomass briquette, where (2 =9.866, DF=6, P=0.13). The study concluded that the level of biomass adoption in Maasai-Mau region was relatively low with only 28% of the households using briquettes daily as compared to other sources of energy. The other conclusion from the study was that biomass briquette making materials were readily available with saw dust chippings and charcoal dusts ranking 84.61% and 79.49% respectively. Finally, the study found out that lack of funds and lack of briquette making skills were the highest challenge to adoption of briquette making technology in the region, being ranked as 88% and 77.6% respectively. The primary recommendations were that the Massai-Mau region residents be educated on biomass briquette making skills, and ensuring that their biomass briquette initiatives are funded to solve the challenges they face while adopting this clean energy mechanism as an alternative source of energy.

The SS methodology is being widely used as a quality management model. Focusing on "Zero Defects" production, the tool that support DNP used in the planning phases, that precede manufacturing is DFSS methodology, suitable for production processes with SS requirement. There is a contradictory question regarding the differences and complementarities between DFSS tool and the SS methodology: to conclude about what is the best strategic decision by two companies, in which one uses the SS and the other uses the DFSS; else more, if it would be a competitor at a higher level with regard to the experience and knowledge, by using both. The case study indicates that given the intrinsic characteristics of the company, common to other Portuguese Small, Medium Enterprises (SMEs), it is clear that the use of DFSS tool turns out to be the most effective, especially when the client is a big company.

Multi-drug resistance (MDR) poses a serious threat in the management of infectious diseases. Slow development of antibiotics and acquirement of resistance mechanisms has led the researchers to focus on development of novel chemotherapeutic agents with broad-spectrum activity having multiple sites of action. Till date, nanoparticles are proven to be a good alternative in management of MDR at least under laboratory conditions. In this study, dextrin was used for eco-friendly green synthesis of silver nanoparticles grafted by poly (methyl methacrylate). The nanoparticles were characterized using UV-vis spectroscopy, FTIR, XRD, SEM, EDX and TEM. The synthesized nanoparticles (PMMA-g-Dex@Ag) were then evaluated for antimicrobial and antibiofilm efficacy on multi-drug resistance bacterial and fungal pathogens. PMMA-g-Dex@Ag proved to be good bacteriostatic even at 4 µg/ml. The minimum inhibitory concentration (MIC) against C. albicans was found to be 16 µg/ml. Moreover, the biofilms of all tested pathogens were reduced by approximately more than 70% in presence of highest tested sub-MIC. Inhibition of exopolysaccharides (EPS) secretion supported the biofilms data and deciphered a possible mode of action. Therefore, such green synthesized nanoparticles can be used as an alternative in management of MDR infection at least for tropical application after careful in vivo validation.

Досліджено спосіб осадження масивних злитків. Запропонований спосіб полягає в осаджені профільованих злитків. Розроблено методику проведення досліджень методом скінчених елементів. Методика дозволила встановлювати закономірності заковування внутрішніх дефектів злитка. Кут граней чотирипроменевих заготовок становив 150°. Відносна глибина увігнутих граней варіювалася в межах 15%…25% від діаметра заготовки. На основі скінчено-елементного моделювання були встановлені середні напруження в меридіональному перерізі після осадження чотирипроменевих заготовок. Величина стискаючих напружень визначалась на базі параметра жорсткості схеми напруженого стану. Теоретичне дослідження дозволило встановити розподіл параметрів напружень в об'ємі поковки при осаджені чотирипроменевих заготовок. Скінчено-елементне дослідження дозволило встановити, що раціональна глибина увігнутих граней повинна становити 15% від діаметра заготовки. При такій глибіні граней відбувається максимальне заковування внутрішнього отвору. Отримані результати пояснюються параметром схеми напруженого стану, який показує наявність стискаючих напружень внаслідок підпору увігнутих граней. Результати скінчено-елементного моделювання перевірялися експериментальними дослідженнями. Крім цього проводилася апробація отриманих результатів на натурних сталевих поковках. У результаті досліджень, виконаних у роботі, було встановлено, що осадження чотирипроменевих заготовок підвищує якість масивних деталей. Ключові слова: кування, осадження, злиток, внутрішній дефект, масивна деталь, чотирипроменева заготовка, увігнуті грані, МСЕ, параметр напруженого стану, напруження що стискають.

The technological scheme for forging of heavy ingots by means of special figured block head is represented in the article. Its influence during the ingot drawing is described. Appliance of specialized tools and cooling-down provided receipt of metal required characteristics and positive results in ultrasonic testing. Combined technological solution gives the opportunity to extend the critical forgings assortment.

Досліджено спосіб осадження масивних злитків. Запропонований спосіб полягає в осаджені профільованих злитків. Розроблено методику проведення досліджень методом скінчених елементів. Методика дозволила встановлювати закономірності заковування внутрішніх дефектів злитка. Кут граней чотирипроменевих заготовок становив 150°. Відносна глибина увігнутих граней варіювалася в межах 15%…25% від діаметра заготовки. На основі скінчено-елементного моделювання були встановлені середні напруження в меридіональному перерізі після осадження чотирипроменевих заготовок. Величина стискаючих напружень визначалась на базі параметра жорсткості схеми напруженого стану. Теоретичне дослідження дозволило встановити розподіл параметрів напружень в об'ємі поковки при осаджені чотирипроменевих заготовок. Скінчено-елементне дослідження дозволило встановити, що раціональна глибина увігнутих граней повинна становити 15% від діаметра заготовки. При такій глибіні граней відбувається максимальне заковування внутрішнього отвору. Отримані результати пояснюються параметром схеми напруженого стану, який показує наявність стискаючих напружень внаслідок підпору увігнутих граней. Результати скінчено-елементного моделювання перевірялися експериментальними дослідженнями. Крім цього проводилася апробація отриманих результатів на натурних сталевих поковках. У результаті досліджень, виконаних у роботі, було встановлено, що осадження чотирипроменевих заготовок підвищує якість масивних деталей. Ключові слова: кування, осадження, злиток, внутрішній дефект, масивна деталь, чотирипроменева заготовка, увігнуті грані, МСЕ, параметр напруженого стану, напруження що стискають.

Досліджено спосіб осадження масивних злитків. Запропонований спосіб полягає в осаджені профільованих злитків. Розроблено методику проведення досліджень методом скінчених елементів. Методика дозволила встановлювати закономірності заковування внутрішніх дефектів злитка. Кут граней чотирипроменевих заготовок становив 150°. Відносна глибина увігнутих граней варіювалася в межах 15%…25% від діаметра заготовки. На основі скінчено-елементного моделювання були встановлені середні напруження в меридіональному перерізі після осадження чотирипроменевих заготовок. Величина стискаючих напружень визначалась на базі параметра жорсткості схеми напруженого стану. Теоретичне дослідження дозволило встановити розподіл параметрів напружень в об'ємі поковки при осаджені чотирипроменевих заготовок. Скінчено-елементне дослідження дозволило встановити, що раціональна глибина увігнутих граней повинна становити 15% від діаметра заготовки. При такій глибіні граней відбувається максимальне заковування внутрішнього отвору. Отримані результати пояснюються параметром схеми напруженого стану, який показує наявність стискаючих напружень внаслідок підпору увігнутих граней. Результати скінчено-елементного моделювання перевірялися експериментальними дослідженнями. Крім цього проводилася апробація отриманих результатів на натурних сталевих поковках. У результаті досліджень, виконаних у роботі, було встановлено, що осадження чотирипроменевих заготовок підвищує якість масивних деталей. Ключові слова: кування, осадження, злиток, внутрішній дефект, масивна деталь, чотирипроменева заготовка, увігнуті грані, МСЕ, параметр напруженого стану, напруження що стискають.

The aim of the work is designing of the new schemes of cut-to-length workpieces of rolled stock and equipment for their implementation. A special construction of the equipment for cutting by breaking of rolled stock has been designed. The energy accumulated into hydro press at the expense of elastic deformation of the machine frame and the drive is used for effective work, namely, application of stress concentrator for cutting by breaking the next workpiece. Mathematical model for indentation of the wedge tool with different form has been designed. Dependences for calculation of energy-power parameters of the process of stress concentrator application have been found. Experimental studies of indentation of the wedge-shaped tool with different forms into the sample confirmed the adequacy of the proposed mathematical models. Calculating errors within 5-10% is related to the need for a more correct choice of the value of sliding friction coefficients. Calculations for steel C 20 (0.2% of the carbon) with triangular stress concentrator show that the amount of accumulated energy of elastic deformation of the machine frame and the drive of hydraulic press will be enough for application of the effective stress concentrator for cutting by breaking the next workpiece (taking into account the bluntness of the cutting edges of the wedge knife). Cutting by breaking . Cutting by shear . Rolled stock . Cutting process . Cut-to-length workpiece . Knife . Accumulated energy . Stress concentrator . Wedge-shaped tool . Breaker . Quality . Power . Moving beam . Press frame . Stamp * Oleg E. Markov

This article investigates the axisymmetric buckling of annular plates under in-plane loading applied at the inner and outer boundaries. The first order shear deformation theory is used to represent the displacement field and the governing equations are derived from the principle of virtual work. Unlike the circular plate in which the prebuckling stress components are constant, for an annulus, these stress components are functions of the radial distance from the plate center. As a consequence, the resulting eigenproblem, which is in the form of coupled differential equations with variable coefficients, does not have a closed form solution. In this article, an asymptotic approximation based on the perturbation technique is introduced to solve this problem. A parametric analysis is performed and the effects of different combinations of boundary conditions at the inner and outer edges, load ratios, inner to outer radius ratios and thicknesses are investigated. The obtained results are in a good agreement with the numerical data and also with the other references.

This article investigates the axisymmetric buckling of annular plates under in-plane loading applied at the inner and outer boundaries. The first order shear deformation theory is used to represent the displacement field and the governing equations are derived from the principle of virtual work. Unlike the circular plate in which the prebuckling stress components are constant, for an annulus, these stress components are functions of the radial distance from the plate center. As a consequence, the resulting eigenproblem, which is in the form of coupled differential equations with variable coefficients, does not have a closed form solution. In this article, an asymptotic approximation based on the perturbation technique is introduced to solve this problem. A parametric analysis is performed and the effects of different combinations of boundary conditions at the inner and outer edges, load ratios, inner to outer radius ratios and thicknesses are investigated. The obtained results are in a good agreement with the numerical data and also with the other references.

The deposition of amorphous carbon electrical contacts on a diamond radiation detector by Pulsed Laser Deposition (PLD) is introduced as a novel technique for producing tissue equivalent x-ray dosimeters. Three devices were fabricated with the following electrical contacts: pure amorphous carbon (labelled Poly-C), amorphous carbon mixed with Nickel (PLD) (labelled Poly-C/Ni) and conventional sputtered Pt (labelled Poly-Pt). To examine the performance of PLD carbon as a contact, a set of x-ray detection characteristics was studied and compared to those of Poly-Pt. This investigation includes current-voltage characteristics, linearity and dose rate dependence, sensitivity and specific sensitivity, photoconductive gain, stability, reproducibility and time response (rise and fall-off times). The experimental results suggest that Poly-C/Ni is suitable for an xray dosimeter. It shows a high signal to noise ratio (SNR) of ~3300, approximately linear relationship between the photocurrent and the dose rate and a sensitivity of 65 nC/Gy. In addition the current signal is stable and reproducible (within 0.26%) and the rise and fall-off times are less than 1.1 and 0.4 seconds, respectively.

Power System Stabilizer (PSS) devices are responsible for providing a damping torque component to generators for reducing fluctuations in the system caused by small perturbations. A Predictive Optimized Adaptive PSS (POA-PSS) to improve the oscillations in a Single Machine Infinite Bus (SMIB) power system is discussed in this paper. POA-PSS provides the optimal design parameters for the classic PSS using an optimization predictive algorithm, which adapts to changes in the inputs of the system. This approach is part of small signal stability analysis, which uses equations in an incremental form around an operating point. Simulation studies on the SMIB power system illustrate that the proposed POA-PSS approach has better performance than the classical PSS. In addition, the effort in the control action of the POA-PSS is much less than that of other approaches considered for comparison.

A new cascade passivity-based control scheme for tracking purposes is proposed in this paper. The proposed scheme is valid for a certain class of nonlinear systems even with unstable zero dynamic, and it is also useful for regulation and stabilization purposes. The cases where all system parameters are assumed to be known ͑nonadaptive case͒ and also the case when they are unknown ͑adaptive case͒ are considered. Some simulation examples are studied to analyze the behavior of the proposed scheme.

The use of performance indices to measure the quality response of dynamical systems is studied in this paper. A definition of a general performance index is proposed which is easy to compute, easy to interpret, and flexible enough to account for different cases commonly presented in practice. The index is tested over several dynamical responses obtained from different systems obtaining good results, in the sense that it is able to rank the behaviors from best to worse, compared with a pattern response.

This work sheds light on the possibility of using control strategies to set the parameters of electric stimulation, a commonly used technique in severe human central nervous system diseases. Currently, parameters of electric stimulation are set through a trial and error process, with a lot of undesirable side effects. Accordingly, and based on the problem of having a population of sick neurons embedded in a population of normal neurons, this work explores the possibility of using a control system based on the behavior of healthy neurons to set current parameters able to modify the electric behavior of sick neurons. Specifically, we posit a knowledge-based expert control system that modifies the firing mode of a thalamic neuron by applying a control stimulation current, with the aim of making it fire in the same mode as a reference thalamic neuron. The controller parameters are tuned based on some characteristics of neurons that have to be determined through experiments before their application, but this controller does not require a detailed mathematical model of each neuron. Simulation results indicate that the proposed system satisfies the control objectives.