Search

Relevance. Enhancing the development of the machinery manufacturing sector significantly contributes to realizing sustainable economic development goals, thereby fostering sustainable growth opportunities across various scales, ranging from local to global. The active advancement of the machine-building sector, which serves as the foundation for sustainable societal progress, demands careful consideration of key factors for the effective operation of machinery manufacturing enterprises with investments being one of the foremost. This highlights the imperative for comprehensive research into the tangible impact of investments in securing the sustainable growth of machine-building businesses. Objective. The paper targets the conduct of analytical research on investment practices and approaches adopted by machine-building enterprises in European Union countries to specify the key investment factors for their sustainable development. Methods. The research is based on both general scientific and specialized methods of economic theory, including methods of theoretical synthesis and comparative analysis. Throughout the research, statistical data from the European Union regarding the operation and performance of machinery manufacturing enterprises were utilized and processed using analysis methods, including comparison, grouping, calculation of averages, and absolute growth. Furthermore, a rating methodology was implemented to identify European Union member states exhibiting the most favorable indicators about the status and dynamics of the machine-building industry. Results. A comprehensive analysis of contemporary scholarly advancements regarding the examination of the role of investments and effective methodologies for their implementation within the machine manufacturing industry was conducted. A grouping of 22 European Union member states was undertaken based on the criteria of the number of machine-building enterprises and indicators of its absolute growth over a ten-year temporal span. The 22 EU member states are grouped by the parameters of the number of machine-building enterprises and their absolute growth over a tenyear period. The average revenue and gross income per enterprise in the selected countries of the European Union’s machinery sector were studied, and based on the results, a ranking was conducted. Utilizing the established ranking of the top selected countries, a comprehensive analysis of key investment indicators was conducted, focusing on parameters that include investments in tangible assets, machinery and equipment, as well as human resources. An overview of investment practices by machinery manufacturing enterprises was undertaken, resulting in the identification of their respective strengths and weaknesses. [ABSTRACT FROM AUTHOR]

• Accident simulation caused the most complex pattern of failure modes. • Laboratory tests do not mimic failure modes caused by a simulated accident. • Test parameters influencing the occurrence of failure modes are discussed. • Modifications to cut resistance testing are proposed. The cut resistance of climbing ropes remains unsolved despite numerous attempts to address it over the past 20 years. Recently, new laboratory test methods have been developed to evaluate rope performance better. This paper compares the fiber failure modes induced by these tests to those observed after a simulated climbing accident. Characteristic fiber failure modes were identified for each test, depending on the position within the rope's cross-section. The results show that current laboratory methods do not comprehensively replicate the breaking mechanisms in the sheath and core that can occur during actual climbing accidents. The UIAA 101 test, however, shows the most potential for accurately reproducing failure modes with certain modifications. [ABSTRACT FROM AUTHOR]

This study discusses the size and distance optimization of hexagonal holes in castellated steel beams. The optimization study of castellated steel beams was performed using finite element method (FEM). The results of optimization analysis are then verified by implementing laboratory tested of 225 mm height castellated steel beam specimens. The specimens were modified from 150 mm height IWF section profile. The model of castellated steel beams is divided into six different variation models which represent 45̊, 50̊, 55̊, 60̊, 65̊ and 70̊ opening angle of hexagonal holes. All castellated steel beam models have 150 mm vertical height holes ( ho ) and each holes are separated with equal distance varies from 0.042 ho to 3.153 ho . The results of FEM analysis indicate that the strength of castellated steel beams increase with a factor of 1.938 to 2.041 compare to 150 mm IWF original profile. The optimum results from FEM analysis was a castellated steel beam that has 60̊ angle size with the optimum hole distance was 0.186 ho to 0.266 ho . Comparison analysis of laboratory test results and FEM analysis results indicated that the difference between those two approaches are not more than 1.011 with COV (coefficient of variation) value 0.069. [ABSTRACT FROM AUTHOR]

How much does a fumble affect the probability of winning an American football game? How balanced should your offense be in order to increase the probability of winning by 10%? These are questions for which the coaching staff of National Football League teams have a clear qualitative answer. Turnovers are costly; turn the ball over several times and you will certainly lose. Nevertheless, what does “several” mean? How “certain” is certainly? In this study, we collected play-by-play data from the past 7 NFL seasons, i.e., 2009–2015, and we build a descriptive model for the probability of winning a game. Despite the fact that our model incorporates simple box score statistics, such as total offensive yards, number of turnovers etc., its overall cross-validation accuracy is 84%. Furthermore, we combine this descriptive model with a statistical bootstrap module to build (short for Football Prediction Matchup) for predicting future match-ups. The contribution of is pertinent to its simplicity and transparency, which however does not sacrifice the system’s performance. In particular, our evaluations indicate that our prediction engine performs on par with the current state-of-the-art systems (e.g., ESPN’s FPI and Microsoft’s Cortana). The latter are typically proprietary but based on their components described publicly they are significantly more complicated than . Moreover, their proprietary nature does not allow for a head-to-head comparison in terms of the core elements of the systems but it should be evident that the features incorporated in are able to capture a large percentage of the observed variance in NFL games. [ABSTRACT FROM AUTHOR]

The toolpath for a sharp corner is important in pocket machining during high-speed machining with numerical control. When milling a sharp corner, a longer tool engagement length generates larger engagement angle and milling force, which reduces the machining precision. To reduce the milling force at a sharp corner and clear up uncut materials, the toolpath at corners must be optimized. In this paper, a new method of generating the toolpath with circular cycle transition at a sharp corner is put forward to provide a new numerically controlled toolpath pattern for pocket milling. On the basis of a common contour-parallel toolpath, minimum radius arcs and circular cycles are added in sequence at a sharp corner. When the cutter comes to the sharp corner, the corner material is removed step by step with a sequence of circular cycles. The validity of the proposed method is confirmed through simulation and tests. The proposed toolpath method is realized by employing the Institute of Manufacturing Technology (IMT) computer-aided manufacturing (CAM) system. The toolpaths at sharp corners generated through commercial software and IMT-CAM software are tested by comparing the corresponding milling forces. It is illustrated in the results that the proposed method reduces the milling force effectively and is of great significance when it is applied in high-speed machining. [ABSTRACT FROM AUTHOR]

This article examines the impact of Cattaneo-Christov heat flux in flows of viscoelastic fluids. Flow is generated by a linear stretching sheet. Influence of thermal relaxation time in the considered heat flux is seen. Mathematical formulation is presented for the boundary layer approach. Suitable transformations lead to a nonlinear differential system. Convergent series solutions of velocity and temperature are achieved. Impacts of various influential parameters on the velocity and temperature are sketched and discussed. Numerical computations are also performed for the skin friction coefficient and heat transfer rate. Our findings reveal that the temperature profile has an inverse relationship with the thermal relaxation parameter and the Prandtl number. Further the temperature profile and thermal boundary layer thickness are lower for Cattaneo-Christov heat flux model in comparison to the classical Fourier’s law of heat conduction. [ABSTRACT FROM AUTHOR]

The flow velocity distribution in partially-filled circular pipe was investigated in this paper. The velocity profile is different from full-filled pipe flow, since the flow is driven by gravity, not by pressure. The research findings show that the position of maximum flow is below the water surface, and varies with the water depth. In the region of near tube wall, the fluid velocity is mainly influenced by the friction of the wall and the pipe bottom slope, and the variation of velocity is similar to full-filled pipe. But near the free water surface, the velocity distribution is mainly affected by the contractive tube wall and the secondary flow, and the variation of the velocity is relatively small. Literature retrieval results show relatively less research has been shown on the practical expression to describe the velocity distribution of partially-filled circular pipe. An expression of two-dimensional (2D) velocity distribution in partially-filled circular pipe flow was derived based on the principle of maximum entropy (POME). Different entropies were compared according to fluid knowledge, and non-extensive entropy was chosen. A new cumulative distribution function (CDF) of partially-filled circular pipe velocity in terms of flow depth was hypothesized. Combined with the CDF hypothesis, the 2D velocity distribution was derived, and the position of maximum velocity distribution was analyzed. The experimental results show that the estimated velocity values based on the principle of maximum Tsallis wavelet entropy are in good agreement with measured values. [ABSTRACT FROM AUTHOR]

Background: Although rotors have been considered among the drivers of atrial fibrillation (AF), the rotor definition is inconsistent. We evaluated the nature of rotors in 2D and 3D in- silico models of persistent AF (PeAF) by analyzing phase singularity (PS), dominant frequency (DF), Shannon entropy (ShEn), and complex fractionated atrial electrogram cycle length (CFAE-CL) and their ablation. Methods: Mother rotor was spatiotemporally defined as stationary reentries with a meandering tip remaining within half the wavelength and lasting longer than 5 s. We generated 2D- and 3D-maps of the PS, DF, ShEn, and CFAE-CL during AF. The spatial correlations and ablation outcomes targeting each parameter were analyzed. Results: 1. In the 2D PeAF model, we observed a mother rotor that matched relatively well with DF (>9 Hz, 71.0%, p<0.001), ShEn (upper 2.5%, 33.2%, p<0.001), and CFAE-CL (lower 2.5%, 23.7%, p<0.001). 2. The 3D-PeAF model also showed mother rotors that had spatial correlations with DF (>5.5 Hz, 39.7%, p<0.001), ShEn (upper 8.5%, 15.1%, p <0.001), and CFAE (lower 8.5%, 8.0%, p = 0.002). 3. In both the 2D and 3D models, virtual ablation targeting the upper 5% of the DF terminated AF within 20 s, but not the ablations based on long-lasting PS, high ShEn area, or lower CFAE-CL area. Conclusion: Mother rotors were observed in both 2D and 3D human AF models. Rotor locations were well represented by DF, and their virtual ablation altered wave dynamics and terminated AF. [ABSTRACT FROM AUTHOR]

Small computer software for analysis of stress concentration factors was developed at Faculty of Mechanical Engineering Sarajevo. Software name is AlfaK. Developing process of the software was presented in previous papers of same authors, in this paper testing of the software was done using numerical analysis. To test accuracy of AlfaK software, analysis of stress concentration factors was done numerically using CATIA V5 commercial software for characteristic geometrical changes in form. Obtained data from numerical analysis are used for comparison with results from AlfaK, and on that way, accuracy of AlfaK software is investigated. [ABSTRACT FROM AUTHOR]

One method used to reduce or eliminate residual vibrations is to modify the input signal by using previously determined system parameters. In order to eliminate the residual vibration completely, these system parameters must be very accurately determined. In real systems, achieving such accuracy may not always be possible. To address this problem and to provide a solution, a new residual vibration elimination method is introduced in this study, which has proven to be useful especially in cases of uncertain parameters of estimated or predicted systems. It is shown that the technique is capable of handling high levels of uncertainty and is able to successfully eliminate or reduce residual vibrations in flexible systems. In this approach, the desired position of the system is primarily divided into two equal parts, and the generated input signal is used to eliminate vibration. This study presents theoretical and experimental results of the techniques applied to a flexible mechanical system; a comparative study of robustness performance is also provided. Simulation and experimental results show that the oscillations are considerably decreased with a high degree of robustness in the presence of uncertainty regarding system parameters. [ABSTRACT FROM AUTHOR]

This study aims to find out whether content-based language instruction improves students' foreign language receptive skills at the engineering faculty. The study was conducted with 50 students from the department of Mechanical Engineering during the fall term of 2012/2013 academic year. Participants consisted of two groups, one target group and one control group. Pretests were applied to both groups at the beginning of the term. Content-based language instruction was implemented to the target group while traditional foreign language courses were implemented to the control group. At the end of the term both groups were given the posttests. The data obtained from the study were evaluated by using SPSS (Statistical Package for Social Sciences) for Windows 20.0 program. In the comparison of quantitative data of the study, descriptive statistical methods (Mean, Standard Deviation) as well as Independent Samples Test were used. The results point out that the use of content-based language instruction significantly develops students' receptive skills in the foreign language courses at the engineering faculty. [ABSTRACT FROM AUTHOR]

Osmotic actuation is a ubiquitous plant-inspired actuation strategy that has a very low power consumption but is capable of generating effective movements in a wide variety of environmental conditions. In light of these features, we aimed to develop a novel, low-power-consumption actuator that is capable of generating suitable forces during a characteristic actuation time on the order of a few minutes. Based on the analysis of plant movements and on osmotic actuation modeling, we designed and fabricated a forward osmosis-based actuator with a typical size of 10 mm and a characteristic time of 2–5 minutes. To the best of our knowledge, this is the fastest osmotic actuator developed so far. Moreover, the achieved timescale can be compared to that of a typical plant cell, thanks to the integrated strategy that we pursued by concurrently addressing and solving design and material issues, as paradigmatically explained by the bioinspired approach. Our osmotic actuator produces forces above 20 N, while containing the power consumption (on the order of 1 mW). Furthermore, based on the agreement between model predictions and experimental observations, we also discuss the actuator performance (including power consumption, maximum force, energy density and thermodynamic efficiency) in relation to existing actuation technologies. In light of the achievements of the present study, the proposed osmotic actuator holds potential for effective exploitation in bioinspired robotics systems. [ABSTRACT FROM AUTHOR]

The development of a rowing jellyfish biomimetic robot termed as “Robojelly”, has led to the discovery of a passive flexible flap located between the flexion point and bell margin on the Aurelia aurita. A comparative analysis of biomimetic robots showed that the presence of a passive flexible flap results in a significant increase in the swimming performance. In this work we further investigate this concept by developing varying flap geometries and comparing their kinematics with A. aurita. It was shown that the animal flap kinematics can be replicated with high fidelity using a passive structure and a flap with curved and tapered geometry gave the most biomimetic performance. A method for identifying the flap location was established by utilizing the bell curvature and the variation of curvature as a function of time. Flaps of constant cross-section and varying lengths were incorporated on the Robojelly to conduct a systematic study of the starting vortex circulation. Circulation was quantified using velocity field measurements obtained from planar Time Resolved Digital Particle Image Velocimetry (TRDPIV). The starting vortex circulation was scaled using a varying orifice model and a pitching panel model. The varying orifice model which has been traditionally considered as the better representation of jellyfish propulsion did not appear to capture the scaling of the starting vortex. In contrast, the pitching panel representation appeared to better scale the governing flow physics and revealed a strong dependence on the flap kinematics and geometry. The results suggest that an alternative description should be considered for rowing jellyfish propulsion, using a pitching panel method instead of the traditional varying orifice model. Finally, the results show the importance of incorporating the entire bell geometry as a function of time in modeling rowing jellyfish propulsion. [ABSTRACT FROM AUTHOR]

Background: Fluorescence and bioluminescence resonance energy transfer (F/BRET) are two forms of Förster resonance energy transfer, which can be used for optical transduction of biosensors. BRET has several advantages over fluorescence-based technologies because it does not require an external light source. There would be benefits in combining BRET transduction with microfluidics but the low luminance of BRET has made this challenging until now. Methodology: We used a thrombin bioprobe based on a form of BRET (BRETH), which uses the BRET1 substrate, native coelenterazine, with the typical BRET2 donor and acceptor proteins linked by a thrombin target peptide. The microfluidic assay was carried out in a Y-shaped microfluidic network. The dependence of the BRETH ratio on the measurement location, flow rate and bioprobe concentration was quantified. Results were compared with the same bioprobe in a static microwell plate assay. Principal Findings: The BRETH thrombin bioprobe has a lower limit of detection (LOD) than previously reported for the equivalent BRET1–based version but it is substantially brighter than the BRET2 version. The normalised BRETH ratio of the bioprobe changed 32% following complete cleavage by thrombin and 31% in the microfluidic format. The LOD for thrombin in the microfluidic format was 27 pM, compared with an LOD of 310 pM, using the same bioprobe in a static microwell assay, and two orders of magnitude lower than reported for other microfluidic chip-based protease assays. Conclusions: These data demonstrate that BRET based microfluidic assays are feasible and that BRETH provides a useful test bed for optimising BRET-based microfluidics. This approach may be convenient for a wide range of applications requiring sensitive detection and/or quantification of chemical or biological analytes. [ABSTRACT FROM AUTHOR]

Pr and Nd co-doped Ce-Zr oxide solid solutions (CZPN) were prepared using co-precipitation and microemulsion methods. It is found that only using supercritical CO2 drying can result in a significant improvement of specific surface area and oxygen storage capacity at lower temperatures for CZPN after aging at 1000°C for 12 h in comparison with those using conventional air drying and even supercritical ethanol drying. Furthermore, the cubic structure was obtained in spite of the fact that the atomic ratio of Ce/(Ce+Zr+Pr+Nd) is as low as 29%. The high thermal stability can be attributed to the loosely aggregated morphology and the resultant Ce enrichment on the nanoparticle surface, which are caused by supercritical CO2 drying due to the elimination of surface tension effects on the gas-liquid interface. [ABSTRACT FROM AUTHOR]

An experimental comparison was conducted for Re = 2,500, free elliptic and rectangular jets inclined at 30° and 60° along major or minor planes. Regardless of the jet base geometry, minor-plane inclined jets produced vortex roll-ups that remain inclined. In contrast, major-plane inclined jets produce significantly stronger vortex-roll-up turning behaviour. Interestingly, major-plane inclined rectangular jets exhibit strong vortex-overturning behaviour, where the vortex-roll-up inclination exceeds the 0° incline angle considerably. Vortex-turning extents and rates are compared between major-plane inclined elliptic and rectangular jets here and support present qualitative observations. Closer inspections reveal that the lack of axis-switching phenomenon in major-plane inclined rectangular jets allows vortex-overturning behaviour. In addition, jet centreline deflection is most sensitive in minor-plane inclined jets, where increasing the incline angle leads to a decrease and an increase in the elliptic and rectangular jet deflection, respectively. [ABSTRACT FROM AUTHOR]

In this study, the effect of a new pulsating blankholder system has been investigated on improving the formability of aluminum 1050 alloy. By using this system, during each pulsating cycle, first, the metal was easily flowed into the die through removing the blankholder force, and then the blankholder force applied by springs was employed to prevent excessive metal flow and wrinkling. Deep drawing of cylindrical cup was simulated by ABAQUS6.7 software. Cup depth, tearing, and thickness distribution of the experimental and numerical analyses were then compared. The results indicated that by using the pulsating blankholder system coupled with proper frequency and gap, the cup depth can be increased and thickness distribution can be improved. Further, good agreement was observed between simulation and experimental results. [ABSTRACT FROM AUTHOR]

Geometric error component identification is needed to realize the geometric error compensation which can significantly enhance the accuracy of multi-axis machine tools. Laser tracker has been applied to geometric error identification of machine tools increasingly due to its high capability in 3D metrology. A general method, based on point measurement using a laser tracker is developed for identifying the geometric error components of multi-axis machine tools in this study. By using this method, all the component errors and location errors of each axis (including the linear axis and rotary axis) of the multi-axis machine tools can be measured. Three pre-described targets are fixed on the stage of the under-test axis which moves step by step. The coordinates of the three targets at every step are determined by a laser tracker based on the sequential multilateration method. The volumetric errors of these three target points at each step can be obtained by comparing the measured values of the target points' coordinates with the ideal values. Then, nine equations can be established by inversely applying the geometric error model of the axis under test, which can explicitly describe the relationship between the geometric error components and volumetric error components, and then the component errors of this axis can be obtained by solving these equations. The location errors of the axis under test can be determined through the curve fitting. In brief, all the geometric error components of a single axis of multi-axis machine tools can be measured by the proposed method. The validity of the proposed method is verified through a series of experiments, and the experimental results indicate that the proposed method is capable of identifying all the geometric error components of multi-axis machine tools of arbitrary configuration. [ABSTRACT FROM AUTHOR]

Considering today's competitive enviroment and the required emission regulations, it becomes increasingly important to reduce fuel consumption and harmful exhaust emissions in order to increase engine output power. This can be obtained by developing a well designed injection system or combustion chamber as well as by decreasing the mechanical losses, which are among the most important parameters affecting engine efficiency. The amount of wear rate and its location in the engine should be known to reduce mechanical losses. Therefore, piston ring-cylinder liner wear, which constitutes the greatest portion of mechanical losses, must be investigated. Researchers have attempted to measure the amount of wear by using various methods. In addition, there are also studies carried out to improve new coating materials or lubricants for reducing wear rate. In this study, these measurement methods are discussed and compared with each other in terms of their advantages and disadvantages. [ABSTRACT FROM AUTHOR]

Abstract: Optimization methods are close to become a common task in the design process of many mechanical engineering fields, specially those related with the use of composite materials which offer the flexibility in the design of both the shape and the material properties and so, are very suitable to any optimization process. While nowadays there exist a large number of solution methods for optimization problems there is not much information about which method may be most reliable for a specific problem. Genetic algorithms have been presented as a family of methods which can handle most of engineering problems. However, starting from a common basic set of rules many algorithms which differ slightly from each other have been implemented even in commercial software packages. This work presents a comparative study of three common Genetic Algorithms: Archive-based Micro Genetic Algorithm (AMGA), Neighborhood Cultivation Genetic Algorithm (NCGA) and Non-dominate Sorting Genetic Algorithm II (NSGA-II) considering three different strategies for the initial population. Their performance in terms of solution, computational time and number of generations was compared. The benchmark problem was the optimization of a T-shaped stringer commonly used in CFRP stiffened panels. The objectives of the optimization were to minimize the mass and to maximize the critical buckling load. The comparative study reveals that NSGA-II and AMGA seem the most suitable algorithms for this kind of problem. [Copyright &y& Elsevier]

The combustion and emission characteristics of vegetable oils and derivatives are quite different from mineral diesel due to their relatively high viscosity, density, and vaporisation characteristics. These properties affect the fuel spray and the interaction of the spray with air in the combustion chamber therefore it is important to analyse the spray characteristics e. g. spray tip penetration, spray cone angle, spray area, and fuel atomization. Optical techniques for spray visualization and image processing are very efficient to analyse the comparative spray parameters for these fuels. Present research investigates the effect of chamber pressure on spray characteristics of jatropha straight vegetable oils (J100) - blends (J5, J20), and jatropha biodiesel (JB100) - blends (JB5, JB20) vis-à-vis baseline data of mineral diesel. Experiments were performed for all these fuels/ blends injected in a constant volume spray visualisation chamber (cold chamber) at four different chamber pressure (1, 4, 7, and 9 bar, respectively). It was found that J100 and JB100 have the highest spray tip penetration, cone angle, and the spray area followed by J20, J5, mineral diesel and JB20, JB5, mineral diesel, respectively, however J20, J5 and JB20, JB5 have better atomization characteristics as compared to J100 and JB100, respectively. Cone angle was higher for biodiesel blends as compared to straight vegetable oils blends at atmospheric pressure however as the chamber pressure was increased to 9 bar, it became almost equal for both fuel types. Spray parameters are found to be excellent for mineral diesel followed by jatropha biodiesel and jatropha oil. It was found that atomization of fuel becomes superior with increasing chamber pressure. [ABSTRACT FROM AUTHOR]

Multiped robots have become the focus of heated discussion lately, especially in applications involving rescue or military missions and underwater or extra-terrestrial explorations. The surroundings concerned are harsh and hazardous terrains, and predictably the malfunction rate is high. What if a leg is irreparably damaged? The original gait can no longer be used and an alternative gait must be taken for the robot to continue its mission. This paper studies and enumerates preferred alternative gaits for six- and eight-legged robots under a proposed severed leg scheme. A leg is assumed to be completely detachable when a failure occurs. Based on a new criterion called the progressive efficiency (PE), defined via the enhanced gait charts, along with other criteria like the stride length and the longitudinal stability, alternative gaits are evaluated. The tables of recommended gaits in this paper are useful for robots when a leg failure is foreseen. These tables not only provide a guideline as to what alternative gait to use, they also give insight into how important a certain leg is. A comparison between the severed leg scheme and the existing locked-joint strategy is also included. [ABSTRACT FROM AUTHOR]

The objective of the paper is a mutual comparison of different methods for evaluation of mechanical properties of surface layers. Mechanical properties were tested with the use of nanoindentation and microindentation tests. Different loads and constant deformation speed were used in both cases. For the evaluation of mechanical properties, the AISI 304 type Chromium-Nickel steel commonly used in mechanical engineering industry was tested. Knowledge of relations and differences between nano and micromechanical properties is necessary for understanding of mechanical processes continuously occurring in surface layers during cutting processes. [ABSTRACT FROM AUTHOR]

Abstract: This study focuses on the comparison of traditional engineering drawings with a CAD (computer aided design) visualization in terms of user performance and eye movements in an applied context. Twenty-five students of mechanical engineering completed search tasks for measures in two distinct depictions of a car engine component (engineering drawing vs. CAD model). Besides spatial dimensionality, the display types most notably differed in terms of information layout, access and interaction options. The CAD visualization yielded better performance, if users directly manipulated the object, but was inferior, if employed in a conventional static manner, i.e. inspecting only predefined views. An additional eye movement analysis revealed longer fixation durations and a stronger increase of task-relevant fixations over time when interacting with the CAD visualization. This suggests a more focused extraction and filtering of information. We conclude that the three-dimensional CAD visualization can be advantageous if its ability to manipulate is used. [Copyright &y& Elsevier]

Performance comparisons in a bearingless motor with and without passive magnetic bearings (PMBs) are presented. The bearingless motor is actively controlled in two perpendicular x–y axes. The axial and conical movements are supported by PMBs. The experimental results are compared to the calculated ones by 3-D finite-element method. Effectiveness of PMBs is analytically and experimentally investigated in both static and dynamic tests. It is found that a rotational test is successful only with the PMBs. [ABSTRACT FROM PUBLISHER]

The real loading is generally constituted only by the outside forces and torques acting on a system, neglecting other influences. An important problem is the including the aleatory real loading in the strength and reliability estimation. The analysis of the actual state of researches in field promotes an interesting observation: there are not proposed even clear methods and principles in literature regarding the establishment of the model of real loading; these are presented relatively vague omitting essential details for their applying. The strength calculation is based by the correction of the nominal load through factors including the exterior influences. Papers published in Romania in the field of real modeling are also mentioned. Considerations on real loading in the strength and reliability estimation for specific models are presented. There are two models of real loading much used that are discussed in the paper: loading spectra and loading sequences. Final conclusions emphasize the main points of the paper. In this way, the paper offers an up-to-date image on the real loading modeling of the mechanical systems and the new problems that could be focused in future research started at the University POLITEHNICA of Bucharest. [ABSTRACT FROM AUTHOR]

Although many researchers have investigated the use of different powertrain topologies, component sizes, and control strategies in fuel-cell vehicles, a detailed parametric study of the vehicle types must be conducted before a fair comparison of fuel-cell vehicle types can be performed. This paper compares the near-optimal configurations for three topologies of vehicles: fuel-cell-battery, fuel-cell--ultracapacitor, and fuel-cell-battery--ultracapacitor. The objective function includes performance, fuel economy, and powertrain cost. The vehicle models, including detailed dc/dc converter models, are programmed in MATLAB/Simulink for the customized parametric study. A controller variable for each vehicle type is varied in the optimization. [ABSTRACT FROM AUTHOR]

This paper presents a driving simulation whose aim is twofold: 1) to investigate the possibility of reducing motion clearance to achieve compact and low-cost driving simulators and 2) to evaluate multimodal and immersive virtual reality motion restitution in platooning driving. The choice has been made for a driving simulator having at least two degrees of freedom (DOF). These consist of the longitudinal displacement and seat rotations. The simulator is also equipped with a force feedback steering wheel for virtual drive assistance. These components are gathered on a serial kinematics-type platform to facilitate a control scheme and avoid the architecture complexity. A comparative study was made to devise a motion cueing strategy, taking into account both the psychophysical and technological constraints. Experimentations were carried out for several case combinations of the longitudinal displacement and seat rotations. [ABSTRACT FROM AUTHOR]