bluuebunny/crossref_metadata_2025 huggingface dataset:
DESIGN AND OPTIMIZATION OF AN EIGHT-BAR LEGGED WALKING MECHANISM IMITATING A KINETIC SCULPTURE, “WIND BEAST”
Authors: Giesbrecht Daniel , Wu Christine Q. , Sepehri Nariman
Published: April 2018

Legged off-road vehicles exhibit better mobility while moving on rough terrain. Development of legged mechanisms represents a challenging problem and has attracted significant attention from both artists and engineers. In this paper, we present the design of a single-degree-of-freedom legged walking mechanism using the mechanism design theory and optimization to imitate a well-known kinetic sculpture, a Wind Beast. The optimization is set up to: i) minimize the energy input and ii) maximize the stride length. The optimization is based on the dynamic force analysis. A prototype of the optimized walking mechanism with 6 legs was built to demonstrate its smooth motion. The success in designing a legged mechanism capable of imitating the well-known kinetic sculpture using the engineering design theories is a small step bridging the gap between art and engineering.
IMPROVING CRASHWORTHINESS IN RAILCAR AGAINST ROLLOVER
Authors: Riazi Sarmad , Feizi Mohammad Mahdi , Hosseini-Tehrani Parisa
Published: April 2018

Roof strength is critical to survival in rollover accidents in railcars. In this task using LS-DYNA software different scenarios are examined in order to strengthen railcar roof and to improve the crashworthiness features against rollover. The performance of each scenario is investigated through presenting the results of crushing behavior and energy absorption versus displacement response. Eventually, the best solution providing the highest ratio of “Energy absorption per Mass” among the studied model is presented.
INVESTIGATION OF HYBRID AND DIFFERENT CROSS-SECTION COMPOSITE DISC SPRINGS USING FINITE ELEMENT METHOD
Authors: Karakaya Şükrü
Published: April 2018

In this study the effectiveness of composite disc springs with different cross-section and hybrid type are determined by taking into account load capacities, masses, hybridization characteristics and costs of composite disc springs. The disc springs are analyzed with ABAQUS finite elements program by compressing between two rigid plates. The load-deflection characteristics obtained as a result of the analysis are compared with the analytic and experimental studies. Then different cross-section and hybrid composite disc springs were modeled. The trapeze A disc spring were confirmed to be more advantageous in terms of load capacity and mass by investigating the modeled disc springs. The effect of hybridization on hybrid disc springs with standard cross-section was investigated and optimum hybrid disc spring was determined according to cost and maximum loading capacity. Consequently, it is determined that carbon/epoxy plies used for outer layers are more advantageous. But the outer ply subjected to force was damaged thus this layer should be particularly reinforced.
DESIGN AND MODELLING OF FAST SWITCHING EFFICIENT SEAT VALVES FOR DIGITAL DISPLACEMENT PUMPS
Authors: Roemer Daniel B. , Johansen Per , Pedersen Henrik C. , Andersen Torben O.
Published: April 2018

Digital Displacement Fluid Power Pumps/Motors are promising candidates for revolutionizing the efficiency of fluid power systems, which traditionally has suffered from poor efficiencies, especially at part load. The key to obtain efficient part load operation with digital displacement technology lies in the development of very fast switching seat valves with a corresponding low pressure loss. The present article is on design and modelling of such an efficient seat valve, which is a mechatronic approach where considerations of different technology fields must be taken into account. Models include valve orifice flow, valve movement and valve actuation. A design method for selecting the optimum valve diameter and stroke length for a given displacement volume is presented. Furthermore, a prototype valve is manufactured and experimental results show good correspondence with modelled results.
FREE VIBRATION AND BUCKLING OF CANTILEVER BEAMS UNDER LINEARLY VARYING AXIAL LOAD CARRYING AN ECCENTRIC END RIGID BODY
Authors: Lajimi Seyed Amir Mousavi , Heppler Glenn R.
Published: April 2018

Natural frequencies of a clamped axially loaded beam carrying an eccentric end rigid body are computed. A linearly varying non-follower axial force representing the beam’s own weight is taken into consideration. An analytical form of the frequency equation of the structure is obtained and solved numerically. The parameters associated with the end rigid body, the mass, the rotary inertia and the eccentricity, are shown to considerably affect the natural frequencies of the structure. The modified orthogonality conditions of the system are presented. A closed-form of the frequency equation for a beam under constant axial load carrying an eccentric end rigid body is obtained and results are compared with the distributed load case. Based on the exact and approximate computations of the critical buckling load a recommendation is made on the method of including the effect of distributed load for practical purposes.
WHICH WILL WIN IN THE GEAR PUMP TECHNOLOGY
Authors: Zhu Hai-Lin , Pan Jun , Zou Min , Wu Hong-Nen , Qin Xingpei
Published: April 2018

There exist three major problems in current gear pumps. They are unbalanced radial force, big excessive flow pulsation and short working life. In order to solve the problems above, a new type of gear pump with flexible ring gear is introduced. Pumping action is achieved through meshing between a flexible ring gear and a rigid external gear. Thus radial pressure forces are hydraulically balanced and the volumetric displacement is doubled for the new pump.
DIFFERENTIAL EVOLUTION FOR OPTIMIZATION OF PID GAIN IN ELECTRICAL DISCHARGE MACHINING CONTROL SYSTEM
Authors: Andromeda Trias , Yahya Azli , Samion Syahrullail , Baharom Ameruddin , Hashim Nor Liyana
Published: April 2018

PID controller of servo control system maintains the gap between Electrode and workpiece in Electrical Discharge Machining (EDM). Capability of the controller is significant since machining process is a stochastic phenomenon and physical behaviour of the discharge is unpredictable. Therefore, a Proportional Integral Derivative (PID) controller using Differential Evolution (DE) algorithm is designed and applied to an EDM servo actuator system in order to find suitable gain parameters. Simulation results verify the capabilities and effectiveness of the DE algorithm to search the best configuration of PID gain to maintain the electrode position.
OPTIMIZATION OF INJECTION MOLDING PARAMETERS FOR LED LAMPSHADE
Authors: Lee Kingsun , Lin Jui-Chang
Published: April 2018

The unibody of LED (light-emitting diodes) lampshades is fabricated by injection mold; the forming technique is complicated, especially for multi-cavity molds. This study applies a finite element analysis to explore the influences of the shrinkage of LED lampshades. The effect of selected injection parameters and their levels on shrinkage size, and the subsequent design of experiments were accomplished using the Taguchi method. The results were confirmed by experiments, which indicated that the selected injection parameters effectively reduce the shrinkage. The error between optimal estimated value and verified value is within 3.82%.
GENETIC-ALGORITHM-BASED MIX PROPORTION DESIGN METHOD FOR RECYCLED AGGREGATE CONCRETE
Authors: Park Wonjun
Published: April 2018

Several desirable characteristics of concrete, such as strength, slump, durability and low CO2 emission, cannot always be obtained by current conventional mix proportion design methods for recycled aggregate concrete (RAC), because Recycled aggregate generally has lower quality than natural aggregate owing to residual cement paste and various impurities. We treat optimal concrete mix proportioning as a multi-criteria problem, and suggest a new method based on genetic algorithms (GAs) to solve the mix proportion design problem for RAC through a simulated biological evolutionary process. In this method, several fitness functions for the desired properties of concrete, i.e., slump, strength, carbonation speed coefficient, price, and emission of CO2, were considered based on conventional data or adopted from previous studies. We thus arrived at optimal mix proportions for RAC that meet the desired performance criteria.
ROBUST ADAPTIVE TRAJECTORY CONTROL FOR AN OMNIDIRECTIONAL VEHICLE WITH PARAMETRIC UNCERTAINTY
Authors: Yang Ya-Chao , Cheng Chi-Cheng
Published: April 2018

In this paper, a robust adaptive control strategy is proposed for trajectory control of an omnidirectional vehicle with three omni-wheels, which have the ability to move simultaneously with independently rotational motion. The omnidirectional vehicle experiences uncertainties and unknown system parameters. The robust adaptive controller is designed based on the symmetric property of the damping matrix, which allows the matrix can be split into two parts. By the Lyapunov stability, the asymptotic tracking performance can be assured. The proposed control scheme is demonstrated by actual tracking experiments using the omnidirectional vehicle system. Experimental results showed promising tracking performance for the proposed method as compared to traditional sliding mode controller.
OPTIMIZATION OF AN ULTRATHIN CENTRIFUGAL FAN BASED ON THE TAGUCHI METHOD WITH FUZZY LOGICS
Authors: Hsien Kuang-Hung , Huang Shyh-Chour
Published: April 2018

This paper presents the use of fuzzy-based Taguchi method to optimize the design of the ultrathin centrifugal fan with multiple performance characteristics. An orthogonal array, the signal-to-noise (S/N) ratio, multiresponse performance index, analysis of variance (ANOVA), and computational-fluid-dynamics were used to study the multiple-objectives in the ultrathin centrifugal fan design. The design parameters, outlet dimensions, inlet dimensions, blade angle, and impeller diameter were optimized with considerations of the performance characteristics, including volume flow ratio, static pressure, and noise. The results demonstrate that volume flow rate of the new design fan was almost 29% larger than that of the original design. This study also identified the optimized design parameters that affect the cooling performance of the centrifugal fan.
A STUDY OF DIGITAL WATERMARKING RECOGNITION USING ORTHOGONAL CODE SEQUENCES WITH A BACK-PROPAGATION NEURAL NETWORK
Authors: Yen Chih-Ta , Ding Ing-Jr , Lai Zong-Wei
Published: April 2018

Digital watermarking is an encryption technology commonly used to protect intellectual property and copyright. In this study, we restored watermarks that had already been affected by noise interference, used the Walsh–Hadamard codes as the watermark identification codes, and applied salt-and-pepper noise and Gaussian noise to destroy watermarks. First method, we used a low-pass filter and median filter to remove noise interferences. The second one, we used a back-propagation neural network algorithm to suppress noises. We removed nearly all noise and recovered the originally embedded watermarks of Walsh–Hadmard codes.
UNMANNED VEHICLE OBSTACLE DETECTION AND AVOIDANCE USING DANGER ZONE APPROACH
Authors: Wang Ta-Chung , Lin Tz-Jian
Published: April 2018

This paper proposes an obstacle avoidance algorithm for unmanned vehicles in unknown environment. The vehicle uses an ultrasonic sensor and a servo motor which rotates from 0 to 180 degrees to obtain the distance data, and the profile of the obstacle. In this avoidance algorithm we will use the danger zone concept to judge whether the obstacle will cause a possible collision. The danger zone concept surrounds the vehicle through the intersection of semi-algebraic sets. These semi-algebraic sets use the relative velocity of the obstacle to calculate the area in which obstacles will collide with the vehicle within a pre-specified time period. Combining the profile of the boundary of the obstacle with the danger zone concept, a method for determining the safe maneuvers to avoid collisions is also provided.
EVALUATION OF ANALYTICAL AND FINITE ELEMENT MODELING ON PIEZOELECTRIC CANTILEVER BIMORPH ENERGY HARVESTER
Authors: Zhang Long , Williams Keith A. , Xie Zhengchao
Published: April 2018

Harvesting the electrical energy from their working environment has become a feasible choice of realizing self-powered systems or providing supplementary power sources to the battery. In this paper, a pre-loaded piezoelectric cantilever bimorph (PCB) energy harvester is adopted as the research object, for which a single degree-of-freedom analytical model and finite element modeling have been carried out to study its dynamic responses. The laboratory experiments have also been performed to validate the analytical and the finite element modeling. It shows that finite element modeling has a better agreement with the experimental results than the analytical model, while the latter has a rough accuracy and can be used to obtain quick estimations of the dynamic response of the PCB energy harvester in certain cases.
LIQUID–LIQUID MIXTURES FLOW IN MICROCHANNELS
Authors: Fu Ben-Ran
Published: April 2018

This study constitutes an experimental and numerical investigation into the single-phase flow of liquid–liquid mixtures and of water in uniform, converging and diverging microchannels. The experimental results for the pressure drop in three microchannels show good agreement with both theoretical predictions and CFD simulation results. The numerical velocity profiles in microchannels are also presented and show excellent agreement with the analytical velocity profiles. In addition, the pressure distribution prediction for the converging and diverging microchannels is also consistent with that obtained through the CFD results.
MULTI-OBJECTIVE OPTIMAL MECHANICAL POWER FOR TURBINE OF RIVER CURRENT POWER GENERATION USING FUZZY DOMINANT DIRECTED-GRAPH METHOD
Authors: Kuo Jian-Long , Chao Kai-Lun
Published: April 2018

The fuzzy dominant directed graph (fuzzy DDG) method is proposed in this paper to realize the multi-objective optimal mechanical turbine power of a river current (RC) power generation system. The testing case illustrates the problem with vertex S/N ratio values included. Fuzzy potential values are derived. The experimental results are provided to verify the validity of the fuzzy-DDG method. It is clear that this method is applicable; it easily and quickly finds the optimal solution.
MECHANICAL BEHAVIOR OF COPPER THIN FILMS SUBJECTED TO VARIOUS STRAIN RATE LOADINGS
Authors: Chung Kuan-Jung , Lin Chi-Feng , Chiang Wei-Cheng
Published: April 2018

In this study, a micro-force tensile testing machine (MTS Tytron 250) was applied to test the polyimide samples coated with different thicknesses of copper (500–1500 nm). The experiments using different strain rates (1.6 × 10−4 to 1.6 × 10−2 s−1) were conducted to the test vehicles. The results showed that the stress and strain of Cu films were strongly correlated with the strain rate and film thickness. The mechanical strength, yield stress, Young’s modulus, and maximum tensile stress, increase as the strain rate increases or the thickness decreases. Strain rate sensitivity rapidly increases as the thickness decreases from 750 to 500 nm to imply that the workhardening rate increases while the thickness decreases, resulting in a higher probability of brittle failure.
AUTOMATIC DESIGN OF SHIFT-AND-ADD BASED COLOR SPACE CONVERTER USING A GENETIC ALGORITHM
Authors: Chen Ching-Yi , Chen Ching-Han , Ma Chih-Hao , Wu Po-Yi
Published: April 2018

The main purpose of this paper is to investigate a novel design method using a genetic algorithm (GA) to automatically evolve the multiplierless CSC circuit architecture. In order to demonstrate the effectiveness of the described design method, several test images are adopted respectively to perform RGB to YCbCr color conversion experiment. The experimental results represent that the performance of the implemented hardware architecture is good when carrying out color space conversion from RGB to YCbCr. It also has the advantage of being high-speed, low-complexity, and low-area.
SYNCHRONOUS MEASUREMENTS OF FINGER SURFACE TEMPERATURE FROM THREE DIFFERENT KINDS OF TEMPERATURE SENSORS
Authors: Jang Fong-Lin , Lin Chyun-Chau
Published: April 2018

The aim of this study was to explore new valid sensors for temperature biofeedback. Three kinds of temperature sensors (thermography imaging, thermistor, and infrared thermopile) were employed to record participants’ finger surface temperatures simultaneously. The skin temperature readings resulted in strong correlations between sensors. These results suggested that contact and non-contact temperature sensors all had good synchronous temperature covariance in measuring finger surface temperature.
INDOOR LOCALIZATION OF AN OMNI-DIRECTIONAL WHEELED MOBILE ROBOT
Authors: Ginzburg Sasha , Nokleby Scott
Published: April 2018

This paper presents a localization system developed for estimating the pose, i.e., position and orientation, of an omni-directional wheeled mobile robot operating in indoor structured environments. The developed system uses a combination of relative and absolute localization methods for pose estimation. Odometry serves as the relative localization method providing pose estimates through the integration of measurements obtained from shaft encoders on the robot’s drive motors. Absolute localization is achieved with a novel GPS-like system that performs localization of active beacons mounted on the mobile robot based on distance measurements to receivers fixed at known positions in the robot’s indoor workspace. A simple data fusion algorithm is used in the localization system to combine the pose estimates from the two localization methods and achieve improved performance. Experimental results demonstrating the performance of the developed system at localizing the omni-directional robot in an indoor environment are presented.
AN ANALYSIS OF THE DAMAGE TOLERANCE OF LIGHT AIRCRAFT LANDING GEAR
Authors: Chen Pu-Woei , Chang Shu-Han , Siao Jyun-Yuan
Published: April 2018

This study uses the finite element software, FRANC2D, and the life-time analysis software, AFGROW, to perform simulation analyses of the damage tolerance of the landing gear of light aviation vehicles. This study explores the effect that the initial crack positions and different materials have on the life cycle of landing gear under long-term loads. This study also compares the relationship between stress intensity factors and crack growth for four types of aluminum alloys, titanium alloy and alloy steel. The relationship between residual strength and life cycle, in the presence of existing cracks, is also investigated.
ELASTIC BEAM WITH NONLINEAR SUSPENSION AND A DYNAMIC VIBRATION ABSORBER AT THE FREE END
Authors: Wang Yi-Ren , Chang Chia-Man
Published: April 2018

This study considered a slender hinged-free beam with suspension cables simulated using nonlinear springs. We added a time-dependent boundary dynamic vibration absorber (DVA) that was suspended at the free end of the beam to reduce vibration and prevent internal resonance. DVA with various spring constants were considered and the optimal mass range for the DVA to reduce vibration in the main structure was also proposed.
OPTIMAL DESIGN OF HEXAPOD WALKING ROBOT LEG STRUCTURE BASED ON ENERGY CONSUMPTION AND WORKSPACE
Authors: Zhu Ya-guang , Jin Bo , Li Wei , Li Shi-tong
Published: April 2018

In order to achieve the optimal design of the hexapod walking robot leg structure, a combined index of energy consumption and workspace is raised. By deriving the energy consumption functions and analyzing the target workspace, a mathematical model of nonlinear programming with inequality constraints is established. The genetic algorithm coupled with inverse kinematics and trajectory planning in a gait period is utilized to solve the optimization problem. The analysis verifies that the requirements of turning and obstacle overcoming can be satisfied, and the total energy consumption can be reduced. The results show that the optimal parameters not only satisfy the requirement of the target workspace, but also achieve the minimum energy consumption and lower joint torques.
INFLUENCES OF TRAIN SPEED AND AXLE LOADS ON LIFE CYCLE OF RAIL FASTENING CLIPS
Authors: Sadeghi Javad , Fesharaki Mohammad , Khajehdezfuly Amin
Published: April 2018

Railway fastening clips play an important role in the stability and safety of railway track systems. There are various studies conducted on fastening clip failure mechanism. Although the majority of these studies indicate that fatigue is the main cause of clip failure, little attentions has been paid to parameters influencing clip fatigue characteristics. In response to this need, a new testing machine was developed by which the structural and loading conditions of fastening clips are simulated in a laboratory. Clip permanent deformations were measured for various track operational conditions, and consequently correlations were developed between clip plastic defamations and track axle loads as well as train speeds. The results obtained pave the way of determining the required clip maintenance cycles for various track loading conditions.
VIBRATION MODELING OF PARALLEL KINEMATIC MECHANISMS (PKMS) WITH FLEXIBLE LINKS: ADMISSIBLE SHAPE FUNCTIONS
Authors: Mahmoodi Masih , Mills James K. , Benhabib Beno
Published: April 2018

The accuracy of various admissible shape functions, for vibration modeling of flexible links of Parallel Kinematic Mechanisms (PKMs), is investigated as a function of the ratio of the mass of the moving platform to the mass of the link. Knowing that the commonly used shape functions based on “pinned”, “fixed”, or “free” boundary conditions do not incorporate the moving platform mass, “pinned-mass” and “fixed-mass” shape functions are presented herein, and are compared with finite-element based results for various mass ratios. The closest shape functions to the finite-element results are, then, utilized and compared with other shape functions in the subsequent vibration modeling to predict the tooltip response.
MODELING OF SURFACE STRESS EFFECTS ON THE DYNAMIC BEHAVIOR OF ACTUATED NON-CLASSICAL NANO-BRIDGES
Authors: Sedighi Hamid M.
Published: April 2018

The influence of surface stress and small scale on the dynamic pull-in behavior of nano-bridges is investigated in this paper. For this purpose, the governing equation of motion is derived based on the modified couple stress theory and Homotopy Perturbation Method with an auxiliary term is employed to produce the approximate solution of nano-beam vibrations. The effects of actuation voltage, initial conditions, surface energy and length scale parameter on the pull-in instability and fundamental frequency of the system are studied. The accuracy of proposed asymptotic approach is validated with numerical simulations. The obtained results from asymptotic analysis reveal that two terms in series expansions are sufficient to produce an acceptable approximation. The nano-actuator dynamics exhibit periodic and homoclinic orbits.
CONTROLLING BOUNDARY LAYER TRANSITION OVER A SEPARATION BUBBLE: A COMPLEX-LAMELLAR APPROACH
Authors: Kolla Maureen L. , Yokota Jeffrey W.
Published: April 2018

In this paper, we develop a complex-lamellar description of the incompressible flow that exists as a boundary layer transitions from a fully developed laminar to fully developed turbulent flow. This complex-lamellar description is coupled to the shape of the universal intermittency distribution and experimental correlations to obtain a boundary layer model of transition. This transition model is used to analyze the effects of several different freestream turbulence levels on the reattachment location and the length of the resulting separation bubbles. Furthermore, we show that at the separation bubble reattachment location, the resulting boundary layer flow is both turbulent and fully developed. Results obtained from this transition model are compared with, and verified by several different DNS simulations.
MULTIDIMENSIONAL DISSIPATION TECHNIQUE FOR AN AUSM SCHEME ON TRIANGULAR GRIDS
Authors: Phongthanapanich Sutthisak
Published: April 2018

Numerical instability of the AUSM scheme on two-dimensional structured triangular grids is investigated. By examining several test cases, it is found that both numerical flux formulations of the AUSM scheme (so-called the AUSM-M1 and AUSM-M2 schemes) do not have sufficiently robustness to satisfy the shock-induced anomaly so called the carbuncle phenomenon. The modified multidimensional dissipation technique is then proposed in order to heal such shock instability. The dissipation mechanism against perturbations is investigated by applying a linearized discrete analysis to the odd-even decoupling problem. The recursive equations show that the dissipation factor (δ) plays an important role in all perturbations of the AUSM-M1 scheme. But it does not have any effect on the density perturbation of the AUSM-M2 scheme. Finally, the scheme is further extended to achieve the second-order solution accuracy and evaluated theirs robustness against shock instability by solving several test cases.
SEISMIC RESPONSE AND NUMERICAL VERIFICATION FOR A 1/25 SCALED-DOWN REINFORCED CONCRETE REACTOR BUILDING SPECIMEN
Authors: Lin Wei-Ting , Wu Yuan-Chieh , Cheng An , Hsu Hui-Mi
Published: April 2018

In recent years, full-scale specimens for seismic test were important to safety assessment of the structure in nuclear power plants but the full-scale tests were not easy to realize due to the limited capable of the existing shaking table capacity. In Taiwan, it was first time to construct a 1/25 scale-down reinforced concrete reactor building specimen in a nuclear power plant and conduct to study the dynamic properties using shaking table test. The specimen was with a length of 2.9 m, width of 2.9 m, height of 2.9 m and weight of 28 tons and cast using the non-demoulding technology and self-consolidating concrete. The entirety structure was composed of a primary containment (thickness of 10 cm), a secondary containment (thickness of 7.5 cm) and three floors (thickness of 30 and 15 cm). The comparison of measured and calculated results demonstrate that ETABS numerical model was satisfactory and can be further used for numerical shaking table tests and real life structures.
DEVELOPMENT OF TRACKING SYSTEM FOR MOBILE ROBOT USING IMAGE RECOGNITION ALGORITHMS
Authors: Su Kuo-Lan , Li Bo-Yi , Hsia Kuo-Hsien
Published: April 2018

In this paper, an intelligent mobile robot using image processing technology is developed. The mobile robot contains an image system, a loading platform, a balance control system, a PC-based controller, four ultrasonic sensors and a power system. We develop a PC-based control system for image processing and path planning. The mobile robot can track a moving target and adjust the loading platform by the balance control system simultaneously. The image processing based on OpenCV uses two different tracking methods to track moving targets: MTLT (Match Template Learning Tracking) and TLD (Tracking, Learning and Detection). The efficiency of both methods for tracking the moving target on the mobile robot is compared here. The balance control system, with a HOLTEK Semiconductor Company’s HT66F Series 8-bit microprocessor as the processor, uses the PID control law according to the feedback signals of the inclinometer sensor to control the balance level of the loading platform.
ADAPTIVE SPARSE GALERKIN METHODS FOR VIBRATING CONTINUOUS STRUCTURES
Authors: Ahsan Zaid , Uchida Thomas K. , Vyasarayani C.P.
Published: April 2018

Adaptive reduced-order methods are explored for simulating continuous vibrating structures. The Galerkin method is used to convert the governing partial differential equation (PDE) into a finite-dimensional system of ordinary differential equations (ODEs) whose solution approximates that of the original PDE. Sparse projections of the approximate ODE solution are then found at each integration time step by applying either the least absolute shrinkage and selection operator (lasso) or the optimal subset selection method. We apply the two projection schemes to the simulation of a vibrating Euler-Bernoulli beam subjected to nonlinear unilateral and bilateral spring forces. The subset selection approach is found to be superior for this application, as it generates a solution with similar sparsity but substantially lower error than the lasso.
SPECIAL ISSUE ON MECHANISMS, MACHINES AND MECHATRONICS GUEST EDITORIAL
Authors: Hayes M. John D. , Lanteigne Eric
Published: April 2018

not available
SYNCHRONIZATION OF DUAL HOMODROMY ROTORS WITH ECCENTRIC MASSES IN A NONLINEAR VIBRATING SYSTEM
Authors: Zhang Xueliang , Xu Jinlin , Zhao Chunyu , Wen Bangchun
Published: April 2018

The motion equations of a nonlinear vibrating system are given firstly. The nonlinear stiffness of springs is equivalently linearized as a function of the response of system by the asymptotic method. The synchronization criterion of dual homodromy rotors with eccentric masses is derived theoretically, as well as the stability criterion. It is shown that the phase difference is close to zero during a sub-resonant state, otherwise it approaches π. The nonlinear characteristics of system are discussed numerically. By the comparisons among theory, numeric and simulation, the validity of the theory method used is examined.
A SYNTHESIS APPROACH FOR RECONFIGURABLE REDUNDANT PARALLEL KINEMATIC MECHANISMS
Authors: Azulay Hay , Mills James K. , Benhabib Beno
Published: April 2018

The design of a variety of novel Parallel Kinematic Mechanisms (PKMs) in the past three decades, and research into redundancy and reconfigurability have presented researchers with an opportunity to develop reconfigurable PKMs. In this paper, a novel synthesis approach for Reconfigurable Redundant PKMs (RR-PKMs) is presented. The approach, motivated by the required reconfigurability, can help synthesize RR-PKMs that reconfigure into lower mobility sub-configurations, assembly/working modes, and sub-PKMs, without the disassembly of the structure. Implementing the proposed approach for the design of a 5-dof machine tool, has led to the synthesis of a novel 3 × RRPRS based RR-PKM that can reconfigure into four PKMs.
ACTIVE HEAT DISSIPATION SYSTEM USING ADAPTIVE RECURRENT WAVELET NEURAL NETWORK CONTROL
Authors: Lee Yung-Lung , Hsu Shou-Jen , Chen Yen-Bin
Published: April 2018

This paper proposes a novel cooling control system with the intelligent active technique, which is based on the NI-PXI systems structure combined with the heat pipe cooling chips. In order to further solve the controlling problems of nonlinear heat transfer system, the proposed intelligent system involves the PID control, traditional control, and the adaptive recurrent wavelet neural network controller (ARWNNC) control techniques. The traditional control there exists the undesirable control chattering, The PID control the Response of Control cannot be processed immediately and the input voltage saturation phenomenon, the adaptive recurrent wavelet neural network controller, is employed to approximate the ideal controller, while the corresponding parameters are derived by the gradient steepest descent method, thus being provided with the adaptive real-time control ability.
A NEW TEST METHOD FOR SHIPPING PALLETS OF SOLAR PRODUCTS
Authors: Hsu Shu-Tsung , Long Yean-San , Wu Teng-Chun
Published: April 2018

The photovoltaic (PV) industry is expanding rapidly to meet the growing renewable-energy demands globally. The failure-rate analysis indicated that a large portion of the accelerated PV module qualification failures were related to the failure of PV cell itself, which was leading to the yield loss of PV products during shipping or transportation. Therefore, the damaged cell (or module) caused by shipping is always one of the serious problems to impact the long-term reliability of PV product. This paper aims to propose a new test method of reliability evaluation for shipping pallet of solar product. The first scenario is the test pallet shipped in fab (e.g., fork-lift truck or hand-pallet truck). The second scenario is the test pallet transported from fab to fab by different vehicle (e.g., truck, train, aircraft, and shipboard). Consequently, detailed results were applied to SEMI Doc. 5431 and released as SEMI PV56-1214 by voting in December 2014. The solar cell/module/system makers and buyers, or any other party interested like package design, can thus have a common document to refer to when desired.
STATISTICAL ANALYSIS OF CONSTANT-STRESS ACCELERATED DEGRADATION TESTING WITH MULTIPLE PERFORMANCE PARAMETERS
Authors: Sun Fu-Qiang , Li Xiao-Yang , Jiang Tong-Min
Published: April 2018

For the long-life and highly-reliable product, accelerated degradation testing (ADT) method is an effective approach for evaluating life and reliability. However, most of previous researches have been focusing on the ADT method based on single performance parameter. The statistical analysis method of constant-stress ADT (CSADT) with multiple performance parameters based on Principal Component Analysis (PCA) and Support Vector Machine (SVM) is proposed in this paper. PCA is utilized to process the CSADT data in order to reduce the dimension of performance parameters. Then, SVM is applying in modelling the degradation process of the principal components. The engineering example proves that the method is feasible and efficient.
Estimation and monitoring of unmeasured gas turbine variables
Authors: Miró-Zárate Luis Angel , Loboda Igor , Pérez-Ruiz Juan Luis , Toledo-Velázquez Miguel
Published: April 2018

This work proposes a universal data-driven approach to compute and monitor gas turbine unmeasured variables. To this end, a large amount of unmeasured and measured data is first computed at steady state for both baseline and faulty engine conditions using a nonlinear thermodynamic model. On the data generated, polynomial models that relate the unmeasured quantities with the measured variables are then determined. These data-driven models allow the computation of unmeasured variables and their deviations. Accuracy analysis is conducted separately for baseline and current estimates of unmeasured variables and for deviation estimates. All the results prove that the estimates are exact enough. Thus it is possible to obtain a universal fast and accurate method for computing important unmeasured gas turbine quantities that is suitable for practical applications. The method promises a drastic increase in the diagnostic capabilities of online monitoring systems.
Study of the ultrasonic stress relief method for assembly of flex lead in inertial devices
Authors: Sun Yibo , Zou Li , Yang Xinhua
Published: April 2018

The micro inertial device is widely used in the aerospace field when high measuring precision is required. The reaction torque from the residual stress of flex lead, which is generated in the assembly process, is a significant source of error. To address this problem, a stress relief method based on ultrasonic aging is designed and studied in this paper. An experimental platform is established using a high frequency, low amplitude ultrasonic system to improve the uniformity of the plastic stress distribution. The deformation of flex lead is measured by a visioning system. Experiments are carried out for two kinds of flex lead with Φ150 and Φ30 μm in profile diameter. Ultrasonic loading time and amplitude are studied, and results indicate that the released stress increased gradually with ultrasonic loading time in the initial stage. Up to a specific value, it remains constant with the subsequent ultrasonic loading. The ultrasonic loading times required for the flex leads in different sizes to achieve constant balance are different, and longer times are needed for the thicker sizes. The stress relief degree is about 20%, and it can be enhanced by increasing ultrasonic amplitude. But damage will be caused by the enhanced impact from ultrasonic vibration in larger amplitude.
Simplicial homotopy theory, link homology and Khovanov homology
Authors: Kauffman Louis H.
Published: April 2018

This paper shows how, in principle, simplicial methods, including the well-known Dold–Kan construction can be applied to convert link homology theories into homotopy theories. The paper studies particularly the case of Khovanov homology and shows how simplicial structures are implicit in the construction of the Khovanov complex from a link diagram and how the homology of the Khovanov category, with coefficients in an appropriate Frobenius algebra, is related to Khovanov homology. This Khovanov category leads to simplicial groups satisfying the Kan condition that are relevant to a homotopy theory for Khovanov homology.
Strict unimodality of plucking polynomials of rooted trees
Authors: Cheng Zhiyun , Mukherjee Sujoy , Przytycki Józef H. , Wang Xiao , Yang Seung Yeop
Published: April 2018

We classify rooted trees which have strictly unimodal plucking polynomials ([Formula: see text]-polynomials). We also give criteria for a trapezoidal shape of a plucking polynomial. We generalize results of Pak and Panova on strict unimodality of [Formula: see text]-binomial coefficients.
Asymptotic behavior of integer sequences related to knots and (m,n)-anacci constants
Authors: Szczyrba Igor
Published: April 2018

We study the asymptotic behavior of integer sequences related to knots that are generated by linear recurrences. We determine which of the 85 such sequences cataloged in Online Encyclopedia of Integer Sequences have ratios of their consecutive terms converging to a limit. We show that all but one of the ratio limits can be expressed by means of the [Formula: see text]-anacci constants with [Formula: see text] equal to 1 or 2. Finally, we demonstrate how the [Formula: see text]-anacci constants are linked to affine geometry.
Homology, mixed multiplies and Hilbert coefficients of the fiber cone
Authors: D’Cruz Clare , Guerrieri Anna
Published: April 2018

In this paper, we compare the depth of the fiber cone and the associated graded ring. To achieve this, we construct a bi-graded complex corresponding to a bi-graded, Noetherian, Hilbert filtration. The vanishing of the homology modules of this complex helps us to compare the depth of the fiber cone of the filtration and the depth of the corresponding associated graded ring. We also give a formula for the fiber coefficients in terms of the lengths of certain homology modules. We give an upper bound for the first fiber coefficient and show that when this bound is attained, the fiber cone has good depth.
Some properties of the weak product of graphs on lattices
Authors: Nimbhorkar S. K. , Borsarkar U. R.
Published: April 2018

Some properties of the weak product of graphs on lattices are studied. We consider the weak product of the atom-based graphs, the incomparability graphs and the zero-divisor graphs of lattices. The number of edges in the weak product of such graphs is found. It is shown that the weak direct product of the atom-based graphs of two lattices [Formula: see text] and [Formula: see text] cannot be an induced subgraph of the atom-based graph of [Formula: see text].
Biorthogonal wavelet-based multigrid and full approximation scheme for the numerical solution of parabolic partial differential equations
Authors: Shiralashetti S. C. , Angadi L. M. , Deshi A. B.
Published: April 2018

This paper presents biorthogonal wavelet-based multigrid (BWMG) and full approximation scheme (FAS) for the numerical solution of parabolic partial differential equations (PPDEs), which are working horse behind many commercial applications like finger print image compression. Performance of the proposed schemes is better than the existing ones in terms of super convergence with less computational time. Some of the test problems are taken to demonstrate the applicability and validity of the method.
Semigroups of linear transformations with fixed subspaces: Green’s relations, ideals and finiteness conditions
Authors: Chaiya Yanisa , Pookpienlert Chollawat , Sanwong Jintana
Published: April 2018

Let [Formula: see text] be a vector space and [Formula: see text] denote the semigroup (under the composition of maps) of all linear transformations from [Formula: see text] into itself. For a fixed subspace [Formula: see text] of [Formula: see text], let [Formula: see text] be the subsemigroup of [Formula: see text] consisting of all linear transformations on [Formula: see text] which fix all elements in [Formula: see text]. In this paper, we describe Green’s relations, regularity and ideals of [Formula: see text]; and characterize when [Formula: see text] is factorizable, unit-regular and directly finite, from which the results on [Formula: see text] can be recaptured easily when taking [Formula: see text] as a zero subspace of [Formula: see text].
Bounds on subspace codes based on totally isotropic subspace in symplectic spaces and extended symplectic spaces
Authors: Hakimi Poroch Mahdieh
Published: April 2018

In this paper, we propose the Sphere-packing bound, Singleton bound and Gilbert–Varshamov bound on the subspace codes [Formula: see text] based on totally isotropic subspaces in symplectic space [Formula: see text] and on the subspace codes [Formula: see text] based on totally isotropic subspace in extended symplectic space [Formula: see text].
A numerical study of two-dimensional coupled systems and higher order partial differential equations
Authors: Rohila R. , Mittal R. C.
Published: April 2018

In this paper, a new approach and methodology is developed by incorporating differential quadrature technique with Bernstein polynomials. In differential quadrature method, approximations are done in a way that the derivatives of the function are replaced by a linear sum of functional values at the grid points of the given domain. In Bernstein differential quadrature method (BDQM), Bernstein polynomials are employed for spatial discretization so that a system of ordinary differential equations (ODE’s) is obtained which is solved by SSPRK-43 method. The stability of the method is also studied. The accuracy of the present method is checked by performing numerical experiments on two-dimensional coupled Burgers’ and Brusselator systems and fourth-order extended Fisher Kolmogorov (EFK) equation. Implementation of the method is very easy, efficient and capable of reducing the size of computational efforts.
Design and implementation of large space radio telescope antenna
Authors: Ma Xiaofei , Gao Bo , Li Huanxiao , Liu Fan , Li Tuanjie
Published: April 2018

The design of large high-precision antenna is one of the key factors restricting the application and development of antenna. This paper presents a design method for high precision large-scale umbrella-shaped antenna. Studies have been performed on the configuration, cable net forming, mesh optimization, error analysis and rib design to achieve the high precision design. Then, a high-precision umbrella antenna prototype is designed and manufactured based on this method. Finally, the test results of the prototype proved the correctness and feasibility of the proposed method.
Episodic modes of operation in hydrothermal gold systems: Part II. A model for gold deposition
Authors: Hobbs Bruce E. , Ord Alison
Published: April 2018

Coupling between the physical processes intrinsic to a hydrothermal system can lead to episodic and chaotic behaviour. Such behaviour includes variations in both space and time of the temperature, fluid pressure and activity of H
2
S, which result in the deposition of alteration mineral assemblages, zoned pyrite and gold; these variations are multifractal. In particular, the coupling of deformation and simultaneous endothermic and exothermic reactions with fluid flow leads to the highly localized deposition of gold. We discuss the physical and chemical mechanisms for such episodic and localization behaviour and explore the non-linear dynamic reasons why such mechanisms are recorded in the multifractal paragenetic sequence and deformation history. The synchronization of intrinsic episodicity as described here and extrinsic forcing induced by episodic seismicity provides another mechanism for enhancing the yield of gold deposition processes and hence the grade of orogenic gold deposits.
The South Atlantic and Gulf of Mexico salt basins: crustal thinning, subsidence and accommodation for salt and presalt strata
Authors: Rowan Mark G.
Published: April 2018

The South Atlantic and Gulf of Mexico conjugate-margin salt basins display similar relationships between crustal architecture and presalt and salt sequences. 3D and 2D depth-migrated seismic data reveal that: (1) the base salt is mostly smooth but drops into an outer marginal trough just landward of and deeper than oceanic crust; (2) the Moho climbs basinward to shallow depths and is largely absent below the trough; (3) faults are low-angle and asymmetrical beneath the smooth base salt but steeper and symmetrical in the trough; (4) the trough contains triangular highs between faulted lows; and (5) the smooth base salt is underlain by sag sequences that often dip and thicken basinward. The observations suggest that these salt basins shared a common evolution. Crustal faulting gradually shifted basinward. Consequent thermal/loading subsidence plus lower-crustal thinning generated basinward-shifting accommodation for sag sequences, but slow sedimentation relative to subsidence resulted in deep depressions. A switch to symmetrical boudinage of thinned crust created the troughs and possible reactive mantle diapirs. Evaporites formed during this stage, with deposition near sea-level in proximal positions but 2–3 km deep in basin centres. Oceanic spreading separated the salt into conjugate basins, with allochthonous flow out over oceanic crust.
Resistive and elastic work of breathing in older and younger adults during exercise
Authors: Smith Joshua R. , Cross Troy J. , Van Iterson Erik H. , Johnson Bruce D. , Olson Thomas P.
Published: April 2018

It is unknown whether the greater total work of breathing (WOB) with aging is due to greater elastic and/or resistive WOB. We hypothesized that older compared with younger adults would exhibit a greater total WOB at matched ventilations (V̇e) during graded exercise, secondary to greater inspiratory resistive and elastic as well as expiratory resistive WOB. Older (OA: 60 ± 8 yr; n = 9) and younger (YA: 38 ± 7 yr; n = 9) adults performed an incremental cycling test to volitional fatigue. Esophageal pressure, inspiratory (IRV) and expiratory reserve volumes (ERV), expiratory flow limitation (EFL), and ventilatory variables were measured at matched V̇e (i.e., 25, 50, and 75 l/min) during exercise. The inspiratory resistive and elastic as well as expiratory resistive WOB were quantified using the Otis method. At V̇e of 75 l/min, older adults had greater %EFL and larger tidal volumes to inspiratory capacity but smaller relative IRV ( P ≤ 0.03) than younger adults. Older compared with younger adults had greater total WOB at V̇Eof 50 and 75 l/min (OA: 90 ± 43 vs. YA: 49 ± 21 J/min; P < 0.04 for both). At V̇e of 75 l/min, older adults had greater inspiratory elastic and resistive WOB (OA: 44 ± 27 vs. YA: 24 ± 22 and OA: 23 ± 15 vs. YA: 11 ± 3 J/min, respectively, P < 0.03 for both) and expiratory resistive WOB (OA: 23 ± 19 vs. YA: 14 ± 9 J/min, P = 0.02) than younger adults. These data demonstrate that aging-induced pulmonary alterations result in greater inspiratory elastic and resistive as well as expiratory resistive WOB, which may have implications for the integrated response during exercise.

NEW & NOTEWORTHY Aging-induced changes to the pulmonary system result in increased work of breathing (WOB) during exercise. However, it is not known whether this higher WOB with aging is due to differences in elastic and/or resistive WOB. Herein, we demonstrate that older adults exhibited greater inspiratory elastic and resistive as well as expiratory resistive WOB during exercise.