Mechanical Engineering

Precision machining plays a vital role in modern, efficient, and sustainable manufacturing. Monitoring and controlling the clamping forces can influence positioning accuracy, workpiece deformation, thus improving the production outcome. The clamping force must be adapted to the cutting forces, workpiece geometry, and material properties to improve accuracy and control workpiece deformation during machining. The best devices available have a repeatability of ±1 µm, however, with limited precision and repeatability when re-clamping the workpiece. This paper presents the newly developed high-precision adaptable clamping system for controlled high-precision positioning and repositioning of a workpiece in the x-y plane with visual pattern recognition, adjustment, and controlled clamping forces. The clamping system is based on a pneumatic clamping chuck with controlled air pressure on a very accurate CNC machine. FEA calculations of thin-walled workpieces are used for designing associated jaws to ensure workpiece holding, limited forces and limited deformations. Once the workpiece has been removed and re-clamped with the defined forces, the vision device identifies the new workpiece position. Force and position data are collected and analyzed for calculating the repositioning movement in the x, y, and theta axes. The difference between the measured position after re-clamping and the reference position is calculated using a specially developed algorithm, yielding the motion commands to the x, y and theta axis. Using the vision system made it possible to identify an accuracy of ±1 µm and a repeatability of ±0.5 µm.

Background and Objective: Cleanroom is a tightly enclosed environment where airborne particles are under control and is a necessary environment in pharmaceutical industries to produce quality products. Hence, we sought to assess and simulate particle dispersion and track particles in a cleanroom by computational fluid dynamics (CFD) method in a pharmaceutical industry. Materials and Methods: This experimental study was conducted in 2015 in a pharmaceutical industry. We evaluated particle concentration and number in the cleanroom according to ISO 14644 -3 standard. In addition, air flow pattern and particle dispersion in the cleanroom with cleanliness class of C was simulated based on CFD. The results showed that the path of particle movement and distribution and dispersion of particles in the cleanroom are completely dependent on flow shape and the pattern of air flow in the cleanroom. Furthermore, the simulation results showed that wall return had efficiency of higher than 70% for particle sizes of 0.5 and 5 microns. Equipment and tools existing in the cleanroom affect the air flow pattern, and in turn, particle removal efficiency. Moreover, particle dispersion simulation in the cleanroom illustrated that air flow pattern exerts the highest impact on particle removal in cleanrooms.

High speed liquid jet forms when a bubble collapses near a solid boundary. The formation of the jet has both advantages and disadvantages as it causes erosion and damage in the nearby turbomachinery and can be beneficially applied in surface cleaning, fluid pumping, etc. In this paper, three-dimensional bubble oscillation between two curved rigid plates is modeled using boundary integral method (BIM). The bubble is incepted at different locations between the plates to investigate the eccentricity effects on the bubble shape, jet formation, etc. The modified Laplacian smoothing technique is implemented on the bubble surface during the jet development to reduce element distortion. The new model is validated with the Rayleigh-Plesset equation as well as with the available experimental data. It was found that the jet velocity increases, and the number of jets is reduced from two to one as the bubble is horizontally shifted away from the centroid. When the bubble is incepted on the horizontal axisymmetric line the jet is horizontal. However, the jet direction changes as the bubble is incepted closer to one of the plates. Finally, the pressure and velocity fields of the fluid surrounding the bubble are provided for better interpretation of the results.

The face gear is used in the spinning machine to lift the spindle mechanism. The face gear are attach with the heart cam for spinning the yarn about spindle. During the working, the tangential force is acting on face gear, which may cause to break the teeth. The tangential load which is acting on the gear is from pinion. The face gear are working similar to the bevel gear and transmitting the power. The intersection axis of both the pinion and gear at right angle to each other. The failure of the gear is due to low strength of the gear material. The beam strength of the face gear is low as compare to the tangential load that why the face gear fail. By changing the material of gear we can prevent the gear from failure. The redesign involve to change the material or to chance the dimension. But in that case, by changing the dimension likes to change the module and thickness which may affect the working of machines. Similarly to change in the setup of machine, in that case it is desira...

The purpose of incorporating an ejector into vapour compression cycle is to improve the COP by reducing the throttling loss associated with the expansion device. A computer simulation of the improved cycle is carried out using a one-dimensional model based on mass, momentum and energy balances. Refrigerant characteristics were evaluated using NIST subroutines for equations of state solutions. According to the results of simulation of the improved cycle, it has been shown that the geometric parameters of the ejector design have considerable effects on the system's performance. The maximum COP is obtained for F opt whose value is around 10. Several refrigerants are considered; it has been observed, at F opt and for given operating conditions, that the best performances are obtained with R141b. Compared with the standard cycle the COP of the improved cycle shows an increase of about 22%.

We present the first tableau-based decision procedure for PDL with nominals. The procedure is based on a prefix-free clausal tableau system designed as a basis for gracefully degrading reasoners. The clausal system factorizes reasoning into regular, propositional, and modal reasoning. This yields a modular decision procedure and pays off in transparent correctness proofs.

The construction industry is pivotal in advancing infrastructure but also contributes significantly to environmental degradation through waste generation. This research investigates waste management practices in three construction projects in Chittagong, Bangladesh, aiming to develop a feasible waste management policy. Through a rigorous analysis of site-specific data, the study identifies the types and quantities of waste generated and evaluates existing waste management practices. The paper proposes a policy focused on reducing waste through strategic planning, efficient resource utilization, and enhanced recycling efforts. While the study provides a foundational policy framework and contributes to sustainable construction practices, it also acknowledges its limitations due to the sample size and geographical focus. Future research directions include broader application and longitudinal studies to assess the policy's impact, integration of advanced technological tools for waste tracking, and a more in-depth stakeholder analysis to foster inclusive and comprehensive waste management solutions. This work serves as a stepping stone towards more sustainable construction practices, with implications for environmental, economic, and regulatory aspects of construction waste management.

The paper is focused on the structuring of glass wafers to obtain high aspect ratio glass columns with high vertical profile for Micro Electro Mechanical Systems (MEMS). The technique proposed is to pattern columns by mechanical sawing. The sawing parameters have been optimised to achieve a high yield. Different dimensions of the column have been tested and glass columns down to 150 m × 150 m of cross-section and 700 m height have been obtained. They present high aspect ratio (>100) and very good vertical profile (88-90 • ). Hoya SD-2 and Corning Pyrex #7740 glass wafers have been processed with similar results. Different cleaning procedures have been tested to improve the anodic bondability of the samples after sawing. Machined glass columns have also been structured by commercial sand blasting technique and the results are also compared to the sawed samples. The glass wafers with machined columns have been anodically bonded to silicon. Anodic bonding characterisation of glass columns of different sections is also presented. Pull tests confirmed the good bondability of the glass columns.

We have been performing arthroscopic rotator cuff repair since 1991. Short-term results have been previously presented and have been encouraging. Presented here are long-term results (minimum of 8 years postoperative) in a consecutive series of 64 patients who underwent 64 arthroscopic rotator cuff repairs. Three patients had died and 6 could not be located, leaving 55 patients who were reevaluated. We were able to personally interview and examine 48 patients; 7 patients were interviewed by telephone. The average age of these patients was 68 years. The repair technique used in these patients was predominantly our older technique utilizing No. 1 PDS and push-in anchors. Most of the tears were nonretracted crescent shaped tears and were repaired directly end to bone. We have traditionally evaluated our patients using the Modified UCLA (MUCLA) scoring system (45 points maximum). This group of patients was also evaluated using this scoring system. Eight year postoperative American Shoulder and Elbow Society and Constant scores were also determined for this group. For MUCLA scoring, we were able to compare the preoperative scores with the results of our previously published evaluation at 2-3 years and our current evaluation at 8 years. The average preoperative MUCLA score was 17, the 2-3 year score was 41, and the 8 year score was also 41. Excellent results were achieved in 68% at 2-3 years and in 75% at 8 years. Good results were obtained in 25% at 2-3 years and 10% at 8 years. Fair results were obtained in 2% of both 2-3 year and 8 year follow-up groups. Poor results were recorded in 5% at 2-3 years and 13% at 8 years. American Shoulder and Elbow Society Scores at 8 years were as follows: 90.8 average overall score (range 40-100), Average pain score was 0.9. Average ADL score was 27.3. Average strength score was 4.8 (abduction) and 4.9 (IR and ER). Constant Scores at 8 years were as follows: 91.3 average overall score (range 68-100). Average pain score was 13. Average total ADL score was 18.8. Average ROM score was 36.1. Average strength score was 12.3. Average strength score when compared to the unaffected side (operated side score ϫ 25/unaffected side score) was 22.4. We used this comparison value to determine the overall average score. Overall, the results of arthroscopic rotator cuff repair are very good and have shown to be durable at 8 year follow-up. These results compare well to the long-term results of open repairs. It must be noted, however, that these are the results of the repair of only the smaller tears that were undertaken at the time. Currently we are using stronger sutures with higher pull-out strength anchors and are repairing much larger tears. The short-term results of these repairs are also good but their long-term durability must still be determined.

In this study nanostructured (grain size: 81 ± 31 nm) micron-sized pure copper powder was compacted in a die using a uniaxial force at room temperature and at pressures ranging from 0.25 to 1.00 GPa. The pressure range selected was based on an ability of the silicon wafer to withstand the pressure without experiencing mechanical damage. The as-compacted copper compacts were sintered at 200 • C for 2 h in an atmosphere of argon. The purpose of this research study was to optimize the compaction pressure to get properties in the compacted copper sample that makes it suitable for use as an electronic packaging material. The characterization studies revealed that an increase in compaction pressure followed by sintering at a low temperature had a minimal to no influence on grain size but a noticeable influence on both porosity and hardness of the compacted sample. The microhardness of the as-compacted samples was found to be superior to the values obtained for the samples synthesized using the techniques of inert gas deposition and in situ compaction, solution phase synthesis, and plasma pressure compaction. The influence of compaction pressure on hardness of the sintered samples is rationalized in light of its intrinsic influence on microstructural development and processing-related artifacts.

Design optimization in terms of total specific energy requirements has been carried out for an ''L" shaped Rotary tiller blade through the development of a mathematical model. This model mainly includes the forward speed of the machine, the rotational speed, the depth of soil cut, the width of soil cut, the rotor radius, the angle of periphery, the angle of rotation, the specific soil resistance, the dry soil bulk density and volume of soil tilled. At the same working conditions the total specific energy requirement was predicted for the twenty five newly designed ''L" shaped Rotary tiller blades used in this study. The higher total specific energy requirement the lower volume of soil tilled and the most effective and optimum soil tillage operational cost is achieved. Based on the results optimized blades has been selected.

The implementation of EMI in boarding maritime education can help cadets prepare for an increasingly connected global maritime work environment. The application of EMI can help improve cadets' English skills and expand their learning opportunities in accessing the international curriculum. In an increasingly complex global maritime environment requiring good English skills, the use of EMI can help cadets to be ready for future challenges. However, challenges such as increased costs and skilled human resources in teaching in English and providing language support for cadets also need to be addressed in the implementation of EMI in boarder maritime education

This paper addresses sound source detection in an outdoor environment using a quadcopter with a microphone array. As the previously reported method has a high computational cost, we proposed a sound source detection algorithm called multiple signal classification based on incremental generalized singular value decomposition (iGSVD-MUSIC) that detects the sound source location and temporal activity at low computational cost. In addition, to relax the estimation error problem of a noise correlation matrix that is used in iGSVD-MUSIC, we proposed correlation matrix scaling (CMS) to achieve soft whitening of noise. As CMS requires a parameter to decide the degree of whitening, we analyzed the optimal value of the parameter by using numerical simulation. The prototype system based on the proposed methods was evaluated with two types of microphone arrays in an outdoor environment. The experimental results showed that the proposed iGSVD-MUSIC-CMS significantly improves sound source detection performance, and the prototype system achieves real-time processing. Moreover, we successfully clarified the behavior of the CMS parameter by using a numerical simulation in which the empirically-obtained optimal value corresponded with the analytical result. 1

We have studied on robot-audition-based sound source localization using a microphone array embedded on a UAV (unmanned aerial vehicle) to locate people who need assistance in a disaster-stricken area. A localization method with high robustness against noise and a small calculation cost have been proposed to solve a problem specific to the outdoor sound environment. In this paper, the proposed method is extended for practical use, a system based on the method is designed and implemented, and results of sound source localization conducted in the actual outdoor environment are shown. First, a 2.5-dimensional sound source localization method, which is a two-dimensional sound source localization plus distance estimation, is proposed. Then, the offline sound source localization system is structured using the proposed method, and the accuracy of the localization results is evaluated and discussed. As a result, the usability of the proposed extended method and newly developed threedimensional visualization tool is confirmed, and a change in the detection accuracy for different types or distances of the sound source is found. Next, the sound source localization is conducted in real-time by extending the offline system to online to ensure that the detection performance of the offline system is kept in the online system. Moreover, the relationship between the parameters and detection accuracy is evaluated to localize only a target sound source. As a result, indices to determine an appropriate threshold are obtained and localization of a target sound source is realized at a designated accuracy.

We simulate the breakup of cylindrical fibers of a nematic liquid crystal surrounded by a quiescent Newtonian fluid. The nematic is described by the Leslie-Ericksen theory, and the interfacial motion is captured by a phase-field method from the initial linear instability to final breakup. The focus is on the coupling between liquid crystal molecular orientation and the evolution of the interface. In particular, we examine how molecular anchoring on the interface and orientational distortion in the bulk affect the growth of capillary waves. Results show that the nematic order tends to hinder capillary wave development, in qualitative agreement with prior linear instability analysis. For typical materials, however, the effect becomes prominent only for nano-scale fibers. In addition, anisotropic viscosity plays a significant role in the growth rate of the capillary wave. In the nonlinear stage of the instability, neighboring waveforms grow at different speeds and lead to daughter drops of nonuniform sizes, which typically display the bipolar configuration with two boojum defects. Despite quantitative differences, the breakup of nematic fibers proceeds in mostly the same way as Newtonian ones. The numerical simulations are in general agreement with previous experimental observations.

The second normal stress difference N 2 experienced by non-Newtonian fluids flowing in a pipe may give rise to secondary flows in the transverse direction. As a result, one component tends to encapsulate the other in stratified flows. In multilayer coextrusion, such secondary flows tend to distort the interface and affect layer uniformity. This paper presents numerical simulations of the elastically driven encapsulation in two-component stratified viscoelastic fluids. The simulations are based on a phase-field theoretical model and use finite elements with adaptive meshing to resolve the moving interfaces. The results suggest two mechanisms for elastic encapsulation: One due to the mismatch of N 2 between the components and the other due to noncircular geometry of the cross section. In circular pipes, the more elastic fluid tends to protrude into the other component in the center of the pipe and become encapsulated. This produces the curtate cycloid interface shape commonly seen in experiments. If the cross section is noncircular, both the geometric effect and the elastic stratification are at work, and the interfacial motion is determined by the competition of these two mechanisms. This understanding provides an explanation for the anomalous encapsulation of the less elastic component by the more elastic one observed in multilayer coextrusion.

Lattice Boltzmann method (LBM) has become an alternative method of computing a variety of fluid flows, ranging from low Reynolds number laminar flows to highly turbulent flows. For turbulent flows, non-uniform grids are preferred. Taylor series expansion-and least-squares-based LBM (TLLBM) is an effective and convenient way to extend standard LBM to be used on arbitrary meshes. In order to show its ability to solve turbulent flows, we combine it with k-ω and S-A turbulence models. To validate these combinations, the benchmark problems of the turbulent channel flow and the turbulent flow over a backward facing step at Re = 44 000 are simulated. Our results compare well with the analytical solution and the experimental results of Kim et al. [22]. This shows that the combination of TLLBM with turbulence model can solve turbulent flows effectively.

The second normal stress difference N 2 experienced by non-Newtonian fluids flowing in a pipe may give rise to secondary flows in the transverse direction. As a result, one component tends to encapsulate the other in stratified flows. In multilayer coextrusion, such secondary flows tend to distort the interface and affect layer uniformity. This paper presents numerical simulations of the elastically driven encapsulation in two-component stratified viscoelastic fluids. The simulations are based on a phase-field theoretical model and use finite elements with adaptive meshing to resolve the moving interfaces. The results suggest two mechanisms for elastic encapsulation: One due to the mismatch of N 2 between the components and the other due to noncircular geometry of the cross section. In circular pipes, the more elastic fluid tends to protrude into the other component in the center of the pipe and become encapsulated. This produces the curtate cycloid interface shape commonly seen in experiments. If the cross section is noncircular, both the geometric effect and the elastic stratification are at work, and the interfacial motion is determined by the competition of these two mechanisms. This understanding provides an explanation for the anomalous encapsulation of the less elastic component by the more elastic one observed in multilayer coextrusion.

We simulate the breakup of cylindrical fibers of a nematic liquid crystal surrounded by a quiescent Newtonian fluid. The nematic is described by the Leslie-Ericksen theory, and the interfacial motion is captured by a phase-field method from the initial linear instability to final breakup. The focus is on the coupling between liquid crystal molecular orientation and the evolution of the interface. In particular, we examine how molecular anchoring on the interface and orientational distortion in the bulk affect the growth of capillary waves. Results show that the nematic order tends to hinder capillary wave development, in qualitative agreement with prior linear instability analysis. For typical materials, however, the effect becomes prominent only for nano-scale fibers. In addition, anisotropic viscosity plays a significant role in the growth rate of the capillary wave. In the nonlinear stage of the instability, neighboring waveforms grow at different speeds and lead to daughter drops of nonuniform sizes, which typically display the bipolar configuration with two boojum defects. Despite quantitative differences, the breakup of nematic fibers proceeds in mostly the same way as Newtonian ones. The numerical simulations are in general agreement with previous experimental observations.

A forecasting model is constructed for the analysis of the long-run electricity and natural gas requirements of the commercial sector of a regional economy. The methodology combines an econometric model to generate baseline forecasts, a detailed end-use model to evaluate conservation and regulatory program impacts, and a disaggregated economic/demographic model to provide internally consistent forecasts of commercial employment and other relevant economic conditions. The model is estimated and used to provide forecasts of energy use and regulatory impacts in San Diego County, California.

Dehydration reaction of ethanol was investigated in a temperature range of 140-250 • C with three different heteropolyacid catalysts, namely tungstophosphoricacid (TPA), silicotungsticacid (STA) and molybdophosphoricacid (MPA). Very high ethylene yields over 0.75 obtained at 250 • C with TPA was highly promising. At temperatures lower than 180 • C the main product was diethyl-ether. Presence of water vapor was shown to cause some decrease of catalyst activity. Results showing that product selectivities did not change much with the space time in the reactor indicated two parallel routes for the production of ethylene and DEE. Among the three HPA catalysts, the activity trend was obtained as STA > TPA > MPA.

Advancements in data analytics techniques have enabled complex, disparate datasets to be leveraged for alloy design. Identifying outliers in a dataset can reduce noise, identify erroneous and/or anomalous records, prevent overfitting, and improve model assessment and optimization. In this work, two alloy datasets (9-12% Cr ferritic-martensitic steels, and austenitic stainless steels) have been assessed for outliers using unsupervised techniques and supplemented with domain knowledge. Principal component analysis and k-means clustering were applied to the data, and points were assessed as outliers based on their distance from other points in the cluster and from other points in the dataset. The outlier characteristics were investigated to determine both cluster-specific and overall trends in the properties of the outlier points. The approach demonstrated here is extensible to other alloy datasets for outlier identification and evaluation to improve the reliability of machine learning and modeling predictions for advanced alloy design.

Heritage data for the class of 9 to 12 wt pct Cr steels are studied using data science to quantify the statistically significant relationships among multiple processing/microstructure and performance variables. The effort is undertaken to find new martensitic steels for creep life of 10 5 hours or greater at 650 °C and 100 MPa using machine learning. Linear regression and lasso regression were utilized to identify alloying elements that contribute towards better creep strength. Visualization techniques such as t-distributed stochastic neighbor embedding and pair-wire element specific comparisons were utilized to explore information gaps that exist within the data and are in conflict with existing domain knowledge. Combining all results suggest that the next alloy design to be explored should be 9 wt pct Cr with high W (2 to 3 wt pct) and high Co (2 to 3 wt pct) for creep life of 10 5 hours or greater at 650 °C, 100 MPa.

High-entropy alloys (HEAs) have generated interest in recent years due to their unique positioning within the alloy world. By incorporating a number of elements in high proportion, usually of equal atomic percent, they have high configurational entropy, and thus, they hold the promise of interesting and useful properties such as enhanced strength and alloy stability. The present study investigates the mechanical behavior, fracture characteristics, and microstructure of two single-phase FCC HEAs CoCrFeNi and CoCrFeNiMn with some detailed attention given to melting, homogenization, and thermo-mechanical processing. Ingots approaching 8 kg in mass were made by vacuum induction melting to avoid the extrinsic factors inherent to small-scale laboratory button samples. A computationally based homogenization heat treatment was given to both alloys in order to eliminate any solidification segregation. The alloys were then fabricated in the usual way (forging, followed by hot rolling) with typical thermo-mechanical processing parameters employed. Transmission electron microscopy was subsequently used to assess the single-phase nature of the alloys prior to mechanical testing. Tensile specimens (ASTM E8) were prepared with tensile mechanical properties obtained from room temperature through 800 °C. Material from the gage section of selected tensile specimens was extracted to document room and elevated temperature deformation within the HEAs. Fracture surfaces were also examined to note fracture failure modes. The tensile behavior and selected tensile properties were compared with results in the literature for similar alloys.

A two-step aging treatment is applied to nickel-base alloy 718 that has been previously surface-treated by mill finishing (MF) and machine hammer peening (MHP). As a result, a Cr-enriched oxide layer is formed along with a nano-precipitates layer that consists of high precipitate fractions of c 0 /c 00 on the top surface. Surface hardness increases after aging and the compressive residual stress is almost relaxed. The synergistic effects of MHP and aging on pitting corrosion behavior are studied. The results show that the corrosion resistance of the MHP specimens decreases after aging, although the corrosion resistance is still higher than the MF condition.

Observations from past earthquake events indicate that skewed bridges are seismically vulnerable due to induced horizontal inplane rotations of the girder. To date, however, very limited experimental research has been done on the pounding behaviour of skewed bridges. In this study, shake table tests were performed on a single-frame bridge model with adjacent abutments subjected to uniform ground excitations. Bridges with different skew angles, i.e., 0 °, 30 °, and 45 °, were considered. e pounding behaviour was observed using a pair of pounding and measuring heads. e results reveal that poundings could indeed influence the responses of skewed bridges in the longitudinal and transverse directions differently and thus affect the development of the girder rotations. Ignoring pounding effects, the 30 °skewed bridges could experience more girder rotations than the 45 °skewed bridges. With pounding, the bridges with a large skew angle could suffer more opening girder displacements than straight bridges.

Any discussion concerning SiC as a material for MEMS first requires a basic understanding of these Silicon carbide (SiC) has recently attracted micromachining processes. attention as a wide bandgap semiconductor with great potential for microelectromechanical Bulk micromachining was developed in the 1970s systems (MEMS). SiC exhibits excellent electrical, as an extension of IC technology for the fabrication mechanical, and chemical properties, making it of three-dimensional structures.1 Bulk micromachinwell suited for harsh environment applications ing of silicon uses wet and dry etching techniques in where traditional MEMS are constrained by the conjunction with etch masks and etch stops to sculpt physical limitations of silicon (Si). This paper micromechanical devices from the Si substrate. There reviews the material properties, deposition are two key capabilities that make bulk micromachintechniques, micromachining processes, and other ing of Si a viable technology. First, the availability of issues regarding the fabrication of SiC-based anisotropic etchants of Si such as ethylene-diamine sensors and actuators. Special emphasis is placed pyrocatecol (EDP) and potassium hydroxide (KOH), on the properties that make SiC attractive for MEMS, and the Si-based processing techniques which preferentially etch single crystal Si along select that have been adapted to realise SiC MEMS crystal planes. Second, the availability of etch masks structures and devices. An introduction to and etch-stop techniques which can be used in conmicromachining is provided for readers not junction with silicon anisotropic etchants to prevent familiar with MEMS fabrication techniques.

Inductive antenna design for passive wireless implantable use presents several challenges not currently addressed. A small form factor is desired for minimally invasive implantation and monitoring, and a low frequency is necessary for effective through-body power transfer. However, a small inductor limits sensitivity to changes in capacitance at low-frequency operation. It is thus necessary to optimize the inductor for maximal sensitivity while satisfying tight area and low frequency constraints. Here a design methodology is presented for planar circular spiral inductors used with capacitive pressure sensors to form a passive wireless implantable pressure sensor. Several analytical expressions are collected to find the optimal geometric parameters that maximize the quality factor and sensitivity of the sensor frequency response. The analysis is validated through comparison with field solvers and wireless measurements of fabricated devices.

PurposeThese days vehicles' spare parts (SPs) are a very big market, and there is a very high demand for these parts. Forecasting vehicles' SPs price and demand are difficult because of the lack of data and the pricing of the SPs is not following the normal value chain methods like normal products.Design/methodology/approachA proposed model using multiple linear regression was developed as a guide to forecasting demand and price for vehicles' SPs. A case study of selected hybrid vehicle is held to validate the results of the research. This research is an original study depending on quantitative and qualitative methods; some factors are generated from realistic data or are calculated using numerical equations and the analytic hierarchy process (AHP) method; online questionnaire and expert interview survey.FindingsThe price and demand for SPs have a linear relationship with some independent variables is the hypothesis that is tested. Even though the proposed models are gen...

The objective of the present work is to evaluate WEDM control factors for machining die steel (HC-HCr) of different thicknesses ranging 5mm to 80 mm. The experiments are carried out on work pieces by varying the power input. The best power value at which the machining is stable with higher cutting speed is identified. Width of the machined slot is measured and Spark gap is calculated for the machining at the corresponding power. The material removal rate (MRR) is computed. Surface roughness value is measured on the machined surface. The machining parameters at different power inputs are recorded. The experiments are repeated for all the job thicknesses under present study. Optimal process parameters of different sizes of work piece are plotted to and best fit curve is selected by using Analysis of Variance (ANOVA). For these plots mathematical correlations are developed. The developed correlations are analysed statistically for testing the suitability using ORIGIN 8.0 software.

Transfer entropy (TE) captures the directed relationships between two variables. Partial transfer entropy (PTE) accounts for the presence of all confounding variables of a multivariate system and infers only about direct causality. However, the computation of partial transfer entropy involves high dimensional distributions and thus may not be robust in case of many variables. In this work, different variants of the partial transfer entropy are introduced, by building a reduced number of confounding variables based on different scenarios in terms of their interrelationships with the driving or response variable. Connectivity-based PTE variants utilizing the random forests (RF) methodology are evaluated on synthetic time series. The empirical findings indicate the superiority of the suggested variants over transfer entropy and partial transfer entropy, especially in the case of high dimensional systems. The above findings are further highlighted when applying the causality measures on...

" The ORC bottoming section for a commercial micro gas turbine has been studied. " Six different organic working fluids have been considered and compared. " The preliminary designs of both axial and radial turbines have been developed. " Also scroll and reciprocating expanders have been analyzed for comparison. " The best suited machine has to be selected after a detailed analysis in each case.

The demand for interdisciplinary research is increasing in the new millennium to help us understand complex problems and find solutions by integrating the knowledge from different disciplines. The present review is an excellent example of this and shows how unique combination of physics, chemistry, and biological techniques can be used for the evaluation of Indian medicinal herbs used for treating diabetes mellitus. Laser-induced breakdown spectroscopy (LIBS) is a sensitive optical technique that is widely used for its simplicity and versatility. This review presents the most recent application of LIBS for detection of glycemic elements in medicinal plants. The characteristics of matrices, object analysis, use of laser system, and analytical performances with respect to Indian herbs are discussed.

A cycling peloton is the main group of cyclists riding closely together to reduce aerodynamic drag and energy expenditure. Previous studies on small groups of in-line drafting cyclists showed reductions down to 70 to 50% the drag of an isolated rider at same speed and these values have also been used for pelotons. However, inside a tightly packed peloton with multiple rows of riders providing shelter, larger drag reductions can be expected. This paper systematically investigates the drag reductions in two pelotons of 121 cyclists. High-resolution CFD simulations are performed with the RANS equations and the Transition SST-k-ω model. The cyclist wall-adjacent cell size is 20 μm and the total cell count per peloton is nearly 3 billion. The simulations are validated by four windtunnel tests, including one with a peloton of 121 models. The results show that the drag of all cyclists in the peloton decreases compared to that of an isolated rider. In the mid rear of the peloton it reduces down to 5%-10% that of an isolated rider. This corresponds to an "equivalent cycling speed" that is 4.5 to 3.2 times less than the peloton speed. These results can be used to improve cycling strategies.

Wood is traditionally modeled as an orthotropic material, with direction dependent transport properties, in this way homogenizing the specific structure of wood: a cellular material with growth rings, consisting of early wood and late wood layers. In this paper we present a mesoscopic model for vapor transport in wood, where earlywood and latewood are modeled as distinct materials. The sorption and vapor transport properties for early-and latewood are determined using a unit cell model with constant cell geometry. These properties are used in two-dimensional calculations of vapor transport in a piece of wood consisting of several growth rings. The mesoscopic results are compared to measurement results and to macroscopic results using homogenized orthotropic transport properties. For vapor transport in radial and tangential direction the difference between meso-and macro modeling of wood is negligible, justifying the vapor transport modeling with homogenized orthotropic transport properties.

A cycling peloton is the main group of cyclists riding closely together to reduce aerodynamic drag and energy expenditure. Previous studies on small groups of in-line drafting cyclists showed reductions down to 70 to 50% the drag of an isolated rider at same speed and these values have also been used for pelotons. However, inside a tightly packed peloton with multiple rows of riders providing shelter, larger drag reductions can be expected. This paper systematically investigates the drag reductions in two pelotons of 121 cyclists. High-resolution CFD simulations are performed with the RANS equations and the Transition SST-k-ω model. The cyclist wall-adjacent cell size is 20 μm and the total cell count per peloton is nearly 3 billion. The simulations are validated by four windtunnel tests, including one with a peloton of 121 models. The results show that the drag of all cyclists in the peloton decreases compared to that of an isolated rider. In the mid rear of the peloton it reduces down to 5%-10% that of an isolated rider. This corresponds to an "equivalent cycling speed" that is 4.5 to 3.2 times less than the peloton speed. These results can be used to improve cycling strategies.

The article describes trends in the economic development of Georgia with particular emphasis on the role of tourism in the socio-economic development of the Autonomous Republic of Adjara. The paper aims to study the tourism development perspective in Adjara to improve the living conditions of the local population that lives in the highlands and to achieve equal social and economic growth throughout the country. The study used the literature review and mass statistics data analysis methods. In addition, the results of a survey conducted in September 2022 on a sample of 351 respondents (visiting Adjara for tourism purposes) were presented. Results: Rural tourism is currently being discussed extensively by state organizations and other public cooperation partners as an additional source of revenue in the Rural Tourism Supply Chain in the highland areas and for regional development. The work discusses the potential and the quality of tourist products. It has identified the region's current trends and issues of tourism development, the main challenges in rural tourism, and the role of transport systems in developing rural tourism sustainability. The article summarizes the recommendations for local officials in rural tourism sustainability and the importance of their development. Adjara's highlands have quite a challenging landscape. Local government should ensure the acceleration of the infrastructure projects of the Adjara highlands and the arrangement of internal roads, parking lots and infrastructure corresponding to modern standards.

A new modification to the steepest‐descent algorithm for discrete‐time iterative learning control is developed for plant models with multiplicative uncertainty. A theoretical analysis of the algorithm shows that if a tuning parameter is selected to be sufficiently large, the algorithm will result in monotonic convergence provided the plant uncertainty satisfies a positivity condition. This is a major improvement when compared to the standard version of this algorithm, which lacks a mechanism for finding a balance between convergence speed and robustness. The proposed algorithm has been investigated experimentally on an industrial gantry robot and found to display a high degree of robustness to both plant modelling error and initial state error. The algorithm also exhibits both long‐term performance and excellent tracking performance, as demonstrated by experimental tests of up to 4000 iterations. To further examine robustness, the plant has been approximated by simple models includi...

Early detection of tooth cracks is crucial for effective condition-based monitoring and decision making. The scope of this work was to bring more insight into the vibration behavior of spur gears in the presence of single and multiple simultaneous tooth cracks. The investigation was conducted in both time and frequency domains. A finite element analysis was performed to determine the variation in stiffness with respect to the angular position for different combinations of crack lengths. A simplified nonlinear lumped parameter model of a one-stage gearbox with six degrees of freedom was then developed to simulate the vibration response of faulty external spur gears. Four different multiple-crack scenarios were proposed and studied. The performances of various statistical fault detection indicators were considered and investigated. The simulation results obtained via MATLAB indicated that, as the severity of a single crack increases, the values of the time domain statistical indicator...

A series of Cu-C o ferrite based bulk particles (Cu (1-x) Co(x) Fe2O4) in which x is varied from 0.0 to 0.6 were prepared by Solid State reaction route. The influence of the Co content on the structural properties of cubic Nickel ferrites (CuF e2O4) was investigated using Raman spectroscopy. Slight reduction in the lattice parameter of Co doped CuF e2O4 has been observed as compared to the parent CuF e2O4. From Raman scattering spectra, a shoulder like feature has been observed in both parent and doped com pounds which reveals that octahedral site is occupied by Co, Cu and Fe ions and tetrahedral site is occupied by only Fe ion.