Miracle-dz/UniFAR-FTUs huggingface dataset:
Research on accurate modeling and control for pneumatic electric braking system of commercial vehicle based on multi-dynamic parameters measurement

Accurate pressure control and fast dynamic response are vital to the pneumatic electric braking system (PEBS) for those commercial vehicles that require higher regulation precision of braking force on four wheels when braking force distribution is carried out under some conditions. Due to the lagging information acquisition, most feedback-based control algorithms are difficult to further improve the dynamic response of PEBS. Meanwhile, feedforward-based control algorithms like predictive control perform well in improving dynamic performance but because of the large amount of computation and complexity of this kind of control algorithm, it cannot be applied in real-time on the single-chip microcomputer, and it is still in the stage of theoretical research at present. To address this issue and for the sake of engineering reliability, this article presents a logic threshold control scheme combining analogous model predictive control (AMPC) and proportional control. In addition, an experimental device for real-time measuring PEBS multi-dynamic parameters is built. After correcting the key parameters, the precise model is determined and the influence of switching solenoid valve on its dynamic response characteristics is studied. For the control scheme, numerical and physical validation is executed to demonstrate the feasibility of the strategy and for the performance of the controller design. The experimental results show that the dynamic model of PEBS can accurately reflect its pressure characteristics. Furthermore, under different air source pressures, the designed controller can stably control the pressure output of PEBS and ensure that the error is within 0.08 bar. Compared with the traditional control algorithm, the rapidity is improved by 32.5%.
Design and optimization of air-cooled heat sinks for sustainable development

The development of heat sinks for microelectronic applications, which are compatible with sustainable development, involves the achievement of a subtle balance between a superior thermal design, minimum material consumption, and minimum pumping power. Due to the rapid proliferation of electronic systems, substantial material streams and energy consumption rates are associated with the cooling of computers, as well as other categories of electronic equipment. This presentation explores the potential for the least-energy optimization of natural- and forced-convection cooled rectangular plate heat sinks. The results are evaluated in terms of a heat sink coefficient of performance, relating the cooling capability to the energy invested. Guidelines for "sustainable" heat sink designs are suggested.
Simulation of devices based on carbon nanotubes and graphene

The simulation results of different devices based on carbon nanotubes (CNT) and graphene are described in the paper. The combined numerical model of hybrid integrated structures including resonant tunneling diode and field-effect transistor (RTD-FET) is proposed. Simulation of RTD-FET based on CNT of different types (chirality) was realized with the use of the developed model. The technique of express simulation of nanoradio based on CNT of the type I (based on only single CNT) and of the type II (hybrid radio) is developed. Proposed models can be used for calculation of nanoradio characteristics such as: 1) resonant frequency of CNT; 2) oscillation amplitude of СNT; 3) CNT IV-characteristics depending on different factors. Results of device simulation based on single-wall and multi-wall СNT are given in the paper. IV-characteristics of nanoscale resonant tunneling structure based on graphene-on-SiC were calculated. As well as it was investigated the influence of different parameters on the electrical characteristic of graphene-based nanostructures.
Design of Star-Shaped Flextensional Stator for Ultrasonic Motor

When a driving voltage opposite to the piezoelectric polarity is applied on the flextensional stator, it will generate the normal force, of which the operating voltage range of piezoelectric actuators will decrease. This paper presents a novel stator design for producing the normal force in which the driving voltage has the same piezoelectric polarity, which is based on the structure of two multilayer piezoelectric actuators clamped in a star-shaped shell. To obtain the two close resonance frequencies of flexural and translation modes, a genetic algorithm combined with the finite element analysis is employed to find the optimal dimensions for the geometry of the stator. The importance of each design parameter is evaluated through a proposed sensitivity analysis method. A prototype resulting from the optimal design was fabricated and the experimental results are given to show that the stator can generate, in practice, the required coupling resonance mode between 35.15 kHz and 36.49 kHz.
Characterisation of low-loss waveguide bends with offset-optimisation for compact photonic integrated circuits

Use of a semivectorial finite element-based beam propagation method is benchmarked with the results available by using alternative numerical methods to analyse compact optical bends in photonic integrated circuits. It is also shown that the incorporation of the perfectly matched layers boundary condition is a superior approach for the treatment of high radiation loss from compact bends to the more common use of the absorbing boundary conditions. The least squares boundary residual method is employed to calculate the lateral offset necessary to maximise the transmission and simultaneously to minimise the reflection coefficients at the straight-to-bend waveguide interfaces. Using these efficient numerical techniques, the radiation loss, transition loss and the required waveguide offset to maximise the transmission and reduce the reflection are calculated.
Thermal Response Characteristics of Flat Plate Heated by High Temperature and High Speed Flow

According to the view of heat transfer, the process of the fluid flow with high temperature and high speed over a flat plate may be considered as the heat transfer process within a compressible thermal boundary layer. Based on the numerical results of thermal isolation assumption, combining the temperature comparison with modification method, a coupled method of convection heat transfer coefficient with temperature field of the plate is established, and the characteristics of the thermal response for the flat plate is dominated. Take some ribbed plates as instances, the convection heat transfer coefficient and temperature field of the plate are simulated through the provided coupled method. The results show that, not only the position and materials of the plate influence the convection heat transfer coefficient, but also the time.
Factors during tumble drying that influence dimensional stability and distortion of cotton knitted fabrics

The length and width shrinkages, skewness, spirality and moisture content of three weft knitted cotton structures, plain single jersey, interlock and lacoste, were determined at regular intervals during tumble drying. Significant length and width shrinkages occurred in all three structures with the amount of shrinkage increasing rapidly in plain single jersey and lacoste as their moisture contents fell below 30 per cent. Distortion was less affected by tumble drying. An attempt was made to isolate the effects of heat and agitation during tumble drying. It has been demonstrated that similar patterns of shrinkage and distortion occur whether heat is applied during tumble drying or not. The tumbling action in a tumble drier has the greatest influence on the dimensional stability and distortion of weft knitted cotton fabrics.
Associating Driving Behavior with Hysteretic Phenomena of Freeway Traffic Flow

Abstract The overexposure of drivers to congested traffic and/or non-recurrent incidents (such as accidents or adverse weather) significantly affects their driving style. Hysteretic phenomena in the macroscopic fundamental traffic diagram have been linked to aggressive and timid driving. We analyze hysteresis through vehicle trajectories on both a macroscopic and a microscopic level in order to reveal the features of different driving styles in the occurrence of congested conditions. Instances of traffic hysteresis are detected and categorized according to the driver behavior they reflect. Then, their macroscopic and microscopic traffic flow characteristics are estimated and statistically investigated using artificial neural networks. Analysis reveals that changes in spacing and acceleration at the end of the phenomenon appear to be the most critical determinants of driver behavior. Different determinants of hysteresis for aggressive, as well as timid drivers are investigated, quantified and compared.
Control and Robust Vision Relative Navigation for Autonomous Aerial Refueling

A relative navigation and control scheme based on multiple camera systems was presented for autonomous operations in close proximity for autonomous air refueling (AAR) mission. The relative navigation system employed non-iterative fast global optimal pose estimation algorithm, and the result was filtered and fused with velocity’s measurements to increase accuracy and robustness by using Kalman filtering algorithm. To attenuate effect of tanker’s vortex and atmospheric turbulence, an H-infinity tracking control law was designed for docking phase of air refueling. Simulation results showed that accuracy of both vision navigation system and trajectory tracking could meet requirements of aerial refueling.
Risk management algorithm for rear-side collision avoidance using a combined steering torque overlay and differential braking

This paper describes a risk management algorithm for rear-side collision avoidance. The proposed risk management algorithm consists of a supervisor and a coordinator. The supervisor is designed to monitor collision risks between the subject vehicle and approaching vehicle in the adjacent lane. An appropriate criterion of intervention, which satisfies high acceptance to drivers through the consideration of a realistic traffic, has been determined based on the analysis of the kinematics of the vehicles in longitudinal and lateral directions. In order to assist the driver actively and increase driver's safety, a coordinator is designed to combine lateral control using a steering torque overlay by motor-driven power steering and differential braking by vehicle stability control. In order to prevent the collision while limiting actuator's control inputs and vehicle dynamics to safe values for the assurance of the driver's comfort, the Lyapunov theory and linear matrix inequalities based optimisation methods have been used. The proposed risk management algorithm has been evaluated via simulation using CarSim and MATLAB/Simulink.
Compact microstrip low‐pass filter with sharp selection characteristics using triple novel defected structures for UWB applications

In this article, a novel band‐stop filter using defected ground structure (DGS) and defected microstrip structure (DMS) with triple T‐shaped slot and a pair of protruded T‐shaped strips inside the triple rectangular slots is presented. Using these DGS and DMS slots, a quasielliptic low‐pass filter (LPF) was designed, fabricated, and tested. The transmission zeros of the slots can be easily controlled by changing the protruded T‐shaped strip and slot dimensions, without changing the area taken by the structure. The experimental results show good agreement with simulation results and demonstrate that excellent stop‐band performance could be obtained through the proposed LPF. The filters have a cutoff frequency of about 3.14 GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1007–1010, 2014
Hybrid frictional contact particles-in elements

By analyzing functional, geometrical and numerical integration aspects, hybrid frictional contact particles-in-elements are derived from the continuous hybrid formulation of 3D large transformation frictional contact problems given in [BEN 99] [BEN 00a]. The suggested approach is illustrated by some academic and industrial contact tests.
Coaxial multiplexer for time domain reflectrometry measurement of soil water content and bulk electrical conductivity

Time domain reflectometry (TDR) is increasingly used for measurement of soil water content and bulk electrical conductivity in agricultural, hydrological, environmental, and infrastructure research and development. The TDR technique uses reflections (wave forms), from a probe buried in the soil, of a fast rise time voltage step. The advent of automatic systems for collecting many TDR wave forms has brought the need for a multiplexer to connect the probes to a TDR instrument without introducing distortion of the wave form. A 16-channel (1P16T), 50 . coaxial multiplexer was developed to switch the TDR signal. Control is by synchronous serial addressing using three lines capable of producing TTL level signals similar to those from the parallel port of a personal computer. The multiplexer has 16 jumper selectable addresses. Testing on five multiplexers showed that quiescent power consumption was 6 mA at 12 VDC, peak power consumption was 101 mA, and average power consumption during switching was 54 mA. Wave form placement on a cable tester screen was not affected by the multiplexer channel used. The standard deviation (SD) of horizontal placement was 0.012 ns which compares favorably to the 15.6 ns full screen width of the wave form (five multiplexers by 16 channels each = 80 measurements; 30 cm probe length). Multiplexer channel also had negligible effect on computed travel times of the TDR pulse in a water content probe. The SD of 0.011 ns for a mean travel time of 8.68 ns was only slightly larger than the SD of 0.007 ns obtained when 80 wave forms were captured using the first channel of one multiplexer. Corresponding SD values for water content were 0.0006 and 0.0004 m3 m–3, respectively. The multiplexer used and the multiplexer channel had no important effect on the wave form voltage levels needed for determination of bulk electrical conductivity (BEC). The ratio of final voltage to incident voltage, which is directly proportional to conductivity, had a SD of 0.0002 when measured 80 times on channel one of one multiplexer and a SD of 0.0006 when measured once on each of the 16 channels of five multiplexers. Compared with a TDR probe connected directly to the cable tester, adding one multiplexer in series caused no change in travel time or water content, while adding two multiplexers in series caused a change in water content of 0.003 m3 m–3. As each multiplexer was added to the system the voltage ratio increased by 2% in a reproducible and expected way that can be included in system calibration for BEC measurements. The multiplexer developed is reliable and accurate for measurements of soil volumetric water content and bulk electrical conductivity.
Modelling of surge phenomena in a centrifugal compressor: experimental analysis for control

Actually, gas transportation in hydrocarbon industries in several countries is based mainly on the use of centrifugal compressors to ensure precise spots under specified conditions. However, these machines are subjected to very serious phenomenon, such as the surge phenomenon, which presents the state of unstable operation that results in pulsations than can be the main cause of certain dangerous mechanical problem. Therefore, to solve this problem, it is necessary to establish a control law which can manage these devices, where the main goal is to obtain the best performance. On the other hand, it is obvious that to achieve this task, the models of this surge phenomenon have to be well determined earlier. This work proposes tests to validate models of the surge phenomenon in a centrifugal compressor set for anti-surge control when the operating mode is in the unstable regime. Real-time tests on the examined gas compression system were used to generate the experimental results. The developed surge model could better control the considered system.
A CPV Thesis

The viability of a concentrator technology is determined by five interrelated factors: economic benefit, cell performance under concentration, thermal management, optical performance and manufacturability. Considering these factors, the 5- 10x concentration range is ideal for silicon-based receivers because this level of concentration captures the bulk of available economic gains while mitigating technical risk. Significant gains in capital efficiency are forsaken below the 5x concentration level. Above the 10x level of concentration, marginal improvements to economic benefit are achieved, but threats to reliability emerge and tend to erode the available economic benefit. Furthermore, optic solutions that provide for concentration above 10x tend to force a departure from low-profile flat-plate designs that are most adoptable. For silicon based receivers, a 5-10x level of concentration within a traditional module form factor is optimal.
STARTING ON THE RIGHT TRACK: INTRODUCING STUDENTS TO MECHANICAL ENGINEERING WITH A PROJECT-BASED MACHINE DESIGN COURSE

Over the past four years, we have redesigned Harvard’s introductory mechanical engineering course to introduce the principles, practices, and pleasures of mechanical engineering in an accessible format. The main goals of the course are to provide experience in the design process, demonstrate the connection between engineering science and design early in the curriculum, and build student enthusiasm for engineering, serving to attract and retain students. Unlike most introductory mechanical engineering courses, we cover strength of materials and machine elements, material usually presented much later in the curriculum, in order to provide tools for the students to quantitatively evaluate their designs. By providing just enough of this background knowledge to allow for analysis of designs, we demonstrate the connection between engineering science and design early in curriculum and motivate in-depth coverage of these topics in later courses.
Occlusion culling algorithm for rendering complex building scene based on the normal line grouping

Rendering complex building scene like ancient architecture heritage is always a difficult work since there is very high occlusion ratio. According to the architectural structure and the data organization strategy of 3D ChiLin models, a new occlusion culling algorithm is proposed, which is based on the normal line grouping of the models concerned with the building features. By integrating with other accelerate methods such as frustum culling, detail culling, LOD and classifying rendering, this algorithm can improve the rendering speed efficiently.
Common mode rejection ratio for cascaded differential amplifier stages

A simple equation for calculating the total common mode rejection ratio, CMRR/sub T/, for cascaded differential amplifier stages is given, and it is applied to several typical cases in instrumentation circuits. Two factors for each stage, C and D, are defined, and it is shown that, in general, CMRR/sub T/ can be calculated by adding the reciprocals of the equivalent CMRR for each stage, which is defined as the product of its C factor and the product of D factors for the preceding stages. The acceptability of the approximate formulas is verified, and application examples based on typical situations in instrumentation circuits are given. It is shown that the assumptions made to obtain such a simplified equation are acceptable. >
Analysis of Ultralong Friction Pile Based on Gradient Dependent Nonlocal Friction Model

Based on the gradient theory, the gradient dependent nonlocal friction model is established. It is a new model which can describe the nonlocal friction effect. Based on Mindlin’s solution of displacement, an elastic solution of the lateral frictional resistance for ultralong friction pile is derived. The ultralong friction pile is analyzed by using the gradient dependent nonlocal friction model. Compared with the solution to the local friction law, the results shows that nonlocal friction law is feasible and reliable. The study is helpful for understanding the friction mechanism in geotechnical problems. It is a good attempt to set up the more actual and more accurate friction model.
Full-Scale Structural Evaluation of Fatigue Characteristics in High Reclaimed Asphalt Pavement and Warm-Mix Asphalt

Warm-mix asphalt (WMA) and the inclusion of higher percentages of reclaimed asphalt pavement (RAP) are two strategies for developing environmentally friendly pavement structures that can also reduce pavement cost. Although demonstration projects have evaluated the constructability and short-term performance of these technologies in the field, questions remain about the structural characterization and longer-term field performance. As part of the 2009 National Center for Asphalt Technology test track, four sections were constructed; they included both WMA and high-RAP contents (50% RAP). A control section did not include either technology. Every section featured embedded instrumentation that facilitated strain versus temperature characterization under truck loading. Statistical comparisons of measured strain response were conducted at three reference temperatures. At the lowest temperature (50°F), the measured strain in the control section was not statistically different from the strains of the experimental sections. At the intermediate temperature (68°F), strains in the RAP with WMA section were statistically lower than the control, but the other sections were not distinguished from the control. At the highest temperature (110°F), the strain in the control section was statistically higher than all other sections. The WMA sections were next highest, and the RAP sections were the lowest. The base mixtures of each section underwent beam fatigue testing from which fatigue transfer functions were developed. Strains entered into their section-specific transfer functions showed that the RAP–WMA section would perform the best. Continued testing and monitoring of the sections are necessary to validate this finding.
Burnout and Work Engagement Among Cabin Crew: Antecedents and Consequences

Flight attendants play an essential role in ensuring cabin safety and offering services on board. This study applied the job demands-resources model to explore burnout and work engagement among cabin crew and investigate the possible antecedents and consequences, using a sample of 305 Taiwanese flight attendants. The health problems caused by heavy workloads under specific working environments and significant rates of turnover intention were noted. Using structural equation modeling to test the conceptual model, the results reveal that job demands positively relate to burnout, whereas job resources positively relate to work engagement but negatively relate to burnout. In addition, health problems directly induce turnover intention and mediate the relationship between burnout and turnover intention. Elevating the levels of work engagement might be effective in reducing cabin crew's turnover intention.
Support Vector Machine and its Predicting Stability of Partially Stabilized Zirconia by Microwave Heating Preparation

Support vector machines (SVMs) are a promising type of learning machine based on structural risk minimization and statistical learning theory, which can be divided into two categories: support vector classification (SVC) machines and support vector regression machines (SVR). The basic elements and algorithms of SVR machines are discussed. As modeling and prediction methods are introduced into the experiment of microwave preparing partially stabilized zirconia (PSZ) and built the stability prediction model, the better prediction accuracy and the better fitting results are verified and analyzed. This is conducted to elucidate the good generalization performance of SVMs, specially good for dealing with nonlinear data.