bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the Form of Pulse of Excitation on the Speed and Power Parameters of the Linear Pulse Electromechanical Converter of the Induction Type
Authors: Bolyukh Vladimir F. , Katkov Igor I. 
Published: January 2020

Abstract
Linear pulse electromechanical converters (LPEC) of induction type allow providing a high speed of the actuating element in the short active section and creating powerful power impulses with its insignificant movement. One of the ways to improve the electromechanical indicators of LPEC is the formation of current excitation pulses in the inductor using electronic power supply circuits containing a capacitive energy storage device. This publication is a continuation of our previous work on the influence of different parameters and conditions on the performance of LPEC.
Using the developed chain mathematical model, recurrent relations are obtained for calculating the interconnected electromagnetic, mechanical and thermal parameters of LPEC. It has been established that the speed and power electromechanical indicators of LPEC with aperiodic excitation pulse are better than those of LPEC with unipolar excitation, but worse than those of LPEC with oscillating-damped excitation pulse. LPEC with a unipolar excitation pulse, by the end of the working cycle, the smallest temperatures of the inductor and the armature are observed, while for LPEC with a oscillating-damped excitation pulse, the greatest efficiency is ensured, being 24.88%. The highest speed and power electromechanical indicators are provided at LPEC with a step-aperiodic excitation pulse.
Experimental studies of LPEC were conducted when operating as an electromechanical accelerator and a shock-power device. In studies of LPEC, a piezoelectric transducer was used as a shock-power device, which converted mechanical vibrations arising from the impact of the striker on the impact plate into electrical signals. In studies of LPEC, a displacement sensor was used as an electromechanical accelerator. It was established experimentally that the movement of the armature begins with a delay relative to the moment of occurrence of the current pulse and is almost linear in the initial part of the acceleration.
Effect of Grid-Generated Turbulence on the Dynamics of a Flexible Filament Hanging in Cross-Flow
Authors: Silva-Leon Jorge , Cioncolini Andrea 
Published: January 2020

Abstract
This paper describes preliminary experiments carried in a wind tunnel to study the effect of different turbulence intensities (nominally Tu = 0.6, 0.8 and 1.0%) on the dynamics of a flexible silicone filament (length to diameter ratio L/D = 83) hanging in crossflow in the range of reduced velocities of 7 &lt; U* &lt; 108. The turbulence intensity inside the wind tunnel was modified by employing two different grids (porosity β = 0.563 and 0.026). At low reduced velocities the filament was statically reconfigured but remained mostly rectilinear along its length. As the reduced velocity was further increased the filament started vibrating, and beyond a certain critical reduced velocity large-amplitude limit-cycle oscillation motions were observed. It is suggested that the turbulence intensity (shear velocity) affects the onset of the flapping motions and the amplitude of these. However, this behavior also depends on the turbulence integral length scale.
An Experimental Investigation of Electrorheological Fluid Damper Recoil System Used in Heavy Duty Application
Authors: Patil Santosh R. , Krishna S. , Gawade S. S. , Desavale R. G. 
Published: January 2020

Abstract
In this paper, a detailed analysis of a recoil system of an artillery gun has been carried out with a view to minimize recoil length by absorbing the thrust produced due to firing and bring the gun barrel to its original position for the next round of fire. In many structural and defense applications, minimization of recoil length is one of the major concerns. A lot of research work has been carried out on the recoil mechanism of an artillery gun to improve its mobility in the hilly region. The effect of recoil mass displacement and high fire rate to improve the overall efficiency of an artillery gun has been studied. In this work, the performance of an artillery gun recoil system is studied by using a damper with electrorheological (ER) fluid. Experimental and numerical studies are carried out to evaluate the performance of the recoil system in terms of recoil length and total recoil time at different elevation angles of firing, ranging from 0 to 80°. It is seen that the use of developed ER damper in the gun recoil system improves its dynamic performance.
Emergent Behavior in a Population of Thermostatically Controlled Loads With Peer-to-Peer Communication
Authors: Schwartz Ryan , Gardner John F. 
Published: January 2020

Abstract
Thermostatically controlled loads (TCLs) are often considered as a possible resource for demand response (DR) events. However, it is well understood that coordinated control of a large population of previously un-coordinated TCLs may result in load synchronization that results in higher peaks and large uncontrolled swings in aggregate load. In this paper we use agent based modeling to simulate a number of residential air conditioning loads and allow each to communicate a limited amount of information with their nearest neighbors. As a result, we document emergent behavior of this large scale, distributed and nonlinear system. Using the techniques described here, the population of TCLs experienced up to a 30% reduction in peak demand following the DR event. This behavior is shown to be beneficial to the goals of balancing the grid and integrating increasing penetration of variable generators.
Hybrid BCI Controller for a Semi-Autonomous Wheelchair
Authors: Nandikolla Vidya K. , van Leeuwen Travis K. , Hartman Amiel 
Published: January 2020

Abstract
Smart wheelchairs with semi or fully autonomous functions, can greatly improve the mobility of physically impaired persons. However, most are controlled using inputs that require physical manipulation (e.g. joystick controllers) and for persons with severe physical impairments this method of control can be too demanding. A noninvasive brain-computer interface (BCI) technology-based controller could bridge between the smart wheelchairs users and physically impaired persons with severe conditions. Current BCI controlled wheelchairs rely on detecting steady-state visually evoked potential (SSVEP) responses as these typically have the greatest data transfer rate. However, this method requires the user to focus on a screen for an extended period of time. This causes strain on the user and takes their attention away from their surroundings, which could be dangerous in a scenario that requires navigation around multiple moving objects. The focus of this project is to design a hybrid BCI controller using an electroencephalogram (EEG) headset to detect hand motor imagery (MI) and jaw electromyography (EMG) signals to control a smart wheelchair in conjunction with its semi-autonomous capabilities. A controller of this kind is well-known to have low data transfer rates, and therefore has lower accuracy and longer response times as compared to other controllers. However, a properly structured controller hierarchy between the BCI controller and semi-autonomous system is developed to compensate the limitations of the controller’s accuracy.
The Use of Qualitative Data Analysis for the Evaluation of Design Ethnography Training Among Undergraduate Engineering Students
Authors: Lai Heather L. , Eaton Tara 
Published: January 2020

Abstract
While qualitative data analysis (QDA) is an established method in education research, QDA is less common in engineering research and may be a challenge for engineering faculty not formally trained in qualitative methods to apply it in engineering education. The following describes the collaborative effort between an engineering design instructor and an anthropologist who used QDA to evaluate the implementation of design ethnography training in a third-year biomedical engineering design course. In their partnership, the study investigators examined student perspectives regarding design ethnography training and how such training in an engineering curriculum may prepare students for careers in biomedical design.
Data for the study consisted of reflective essays (N = 42) that the students completed following two primary exercises dedicated to design ethnography skills training. Investigators input typed and anonymized text files of the student essays into ATLAS.ti X7, a qualitative data analysis software program, for qualitative content analysis. QDA was conducted using the constant comparison method to inductively identify pertinent themes. Throughout the QDA process, the investigators routinely met to discuss, merge and interpret themes as needed. Upon the finalization of themes, researchers re-reviewed the data using the finalized codebook (a list of themes and their definitions) for coding reliability. This regular contact was invaluable for the engineering instructor, providing instruction on the process necessary for proper application of QDA.
The unique partnership between investigators offered the engineering design instructor the opportunity to evaluate engineering student perceptions of a new curriculum implementation in an in-depth manner not commonly attempted in engineering education. Results from the QDA showed that the incorporation of design ethnography skills training into an engineering design curriculum increased student awareness of the value of ethnography in understanding user environments while offering engineering students the opportunity to develop better observation skills. This study was successful not only in demonstrating efficacy of design ethnography training among undergraduate engineering students, but it also serves as an example of how QDA may be applied by engineering instructors for the evaluation of student experience and work in engineering education.
Determination of Future Robust Product Features for Modular Product Family Design
Authors: Greve Erik , Rennpferdt Christoph , Hartwich Tobias , Krause Dieter 
Published: January 2020

Abstract
Modular product architecture design allows product variants to be derived with little effort and cost. An essential part of designing modular product architectures is fulfilling customer-relevant product features, which represent the differentiating aspects for the customer and, thus, stand for the economic success of a product variant. However, product features are not only subject to high fluctuations due to changing environmental influences, but are also of varying relevance to customers over time. Not considering these aspects in the development phase can lead to costly changes in the product architecture later on. To counteract this, these two perspectives are merged and a methodical approach is introduced that identifies new product features and analyses their future development in the context of customer benefit. For this purpose, the current and future relevance to customers as well as uncertainties are calculated using Adaptive Conjoint Analysis and a Monte Carlo simulation. The results are consolidated in a visualization and the product features are classified according to their future implementation in robust product architecture. The procedure is explained using the example of a product family of vacuum cleaning robots.
Influence of Pocket Wear on the Dynamic Characteristics of High-Speed Ball Bearing Cage
Authors: Li Hui , Li Chen , Li Yuan , Qi Shemiao , Liu Yi , Liu Heng 
Published: January 2020

Abstract
Aiming at the problem of wear on the cage-pocket during the operation of high speed rolling bearing, a dynamic model of high-speed ball bearing was established considering the wear loss of the ball-pocket, and the simulation was carried out to research on the interaction among the balls, the inner ring, the outer ring and the cage with different wear loss of the ball-pocket. The effect of the pocket wear on the trajectory of the cage’s mass center and the skidding ratio of cage was obtained. It was found out that the mass-center trajectory of the cage presents two vibration modes with different amplitudes which emerges alternatively. Moreover, the wear loss of the ball-pocket has little effect on the average skidding ratio of the cage, however, the fluctuation amplitude would become larger as the wear increase. This study can provide theoretical guidance for the design of bearing cage pocket size.
Robust Control-Oriented Modeling of a Feedback-Linearized Powered Pediatric Lower-Limb Orthosis
Authors: Laubscher Curt A. , Sawicki Jerzy T. 
Published: January 2020

Abstract
Linear robust control techniques such as μ-synthesis can be used to design controllers for linear systems to guarantee specified performance criteria in the presence of modeling uncertainties, disturbances, and sensor noise. However, these techniques are rather uncommon in robotics due to the nonlinear nature of the plant where direct application would require large model uncertainties and therefore may only create a satisfactory controller if using lenient performance criteria. The inclusion of feedback linearization can rectify this by effectively converting the plant from a nonlinear system to a linear one, resulting in smaller model uncertainties.
This paper proposes the use of feedback linearization to enable the use of linear robust control techniques on nonlinear systems. This approach is applied to a provisional version of a powered pediatric lower-limb orthosis. Sine sweep experiments are conducted to determine frequency response data for the system with and without feedback linearization. Models are identified to match the recorded data using optimization for both cases. Uncertainties are manually applied such that they encapsulate the observed measurements. The amount of uncertainties in the two models are quantified and a comparison shows that the uncertainties in the feedback-linearized system are smaller than in the system without feedback linearization.
Dynamics of Compound Droplet Passing Through a Conical CTC Microfilter
Authors: Chang Pengliang , Hashem Mohammad Abul , Chen Xiaolin , Tan Hua 
Published: January 2020

Abstract
Circulating tumor cells (CTCs) are important biomarkers which can be used for early-stage cancer detection and treatment. Developing an efficient approach to detect CTCs from peripheral blood is a challenging problem due to their extreme rarity. The CTC microfiltration provides a good solution as a critical method based on the physical property of CTCs. In this study, we employed a compound droplet model to investigate the transport behavior of a CTC squeezing through a conical-shaped microfilter. The compound droplet model of CTC is composed of a cortical membrane, cytoplasm and the nucleus. Numerically, we used the octree-based Adaptive-Mesh-Refinement (AMR) to analyze the deformable CTC flowing through a microfilter with non-uniform cross-sections. We investigated the pressure-deformability behavior of the cell with different nuclear to cytoplasmic ratio (N/C ratio). Our study revealed that the nucleus smaller than the filter pore did not affect the pressure behaviors significantly. However, when the nucleus is larger than the filter pore size, the pressure behaviors are greatly affected. We also studied the effects of the flow rate on the cell squeezing process. We found that the critical pressure increases significantly with the flow rate. Our study can provide valuable information about cell transport behavior in conical-shaped microfilters.
Stability Analysis of Demand Response Systems Utilizing Locally Communicating Thermostatically Controlled Loads
Authors: Kuwada Jason , Gardner John F. 
Published: January 2020

Abstract
Thermostatically Controlled Loads (TCLs) have shown great potential for Demand Response (DR) events. However, it has been commonly seen that DR events using TCLs may cause load synchronization and unwanted oscillatory effects, especially in homogeneous populations. In an attempt to mitigate the negative impacts of DR events, a decentralized method is proposed that modifies each thermostat behavior based on the activity of nearby TCLs. This feedback introduces the possibility of instability in the aggregate behavior. A stability analysis is performed on a model of the aggregate system and the results of that analysis compared to simulation results. Several populations were considered, varying population size, communication topology, thermostat deadband and heterogeneity of the population. While the linearized analysis failed to accurately predict instabilities in the aggregate system, it did provide insight into global behavior.
Design Resilience of Demand Response Systems Utilizing Locally Communicating Thermostatically Controlled Loads
Authors: Kuwada Jason , Mehrpouyan Hoda , Gardner John F. 
Published: January 2020

Abstract
Thermostatically Controlled Loads (TCLs) have shown great potential for Demand Response (DR) events. The focus of this study is to investigate the effects of adding communication throughout a population of TCLs on the resilience of the system. A Metric for resilience is calculated on varying populations of TCLs and verified with agent based modeling simulations. At the core of this study is an added thermostat criterion created from the combination of a proportional gain and the average compressor operating state of neighboring TCLs. Differing connection architectures are also analyzed. Resilience of the systems under different connection topologies, are calculated by analyzing algebraic connectivity at varying population sizes. The resilience analysis was verified through simulation. Results of the analysis show the effect of on delay schemes and connection architecture on stability limit of each system. Good concurrence was found between predicted and observed resilience for smaller dead-band sizes. Simulations showed varying results on the effect of a simulated attack based on location of the attack within the population.
Modeling Prestress-Driven Buckling Behavior of Elastic Lamina in the Aortic Media
Authors: Tamura Atsutaka , Kato Yuya 
Published: January 2020

Abstract
Mathematical modeling of the thoracic aorta is important for understanding the development and progression of various cardiovascular diseases, helping to detect extraordinary stress distributions of the hypertensive aortic wall, even in early stages. However, it is difficult to ensure the biofidelity of biological materials in formulating a mathematical model. In a freshly isolated aortic media, composed mainly of smooth muscle cell layers (SMLs) and elastic laminae (ELs), circumferential EL waviness and longitudinal EL undulation are often observed because of the structural “buckling” of ELs. This is considered to be closely associated with residual stresses of SMLs and ELs in the aortic wall but the mechanism underlying such EL buckling behavior remains unclear. In the present study, a series of numerical simulations were designed to identify effective mechanical parameters to reproduce EL buckling in the aortic media. We found that prestress initially administered to ELs in the circumferential and axial directions, and the predefined internodal distance, which couples the SML and EL, are essential to computationally reconstruct the circumferential EL waviness and the longitudinal EL undulation in an unloaded state. We also proposed a set of equations based on the numerical results and successfully predicted EL buckling behaviors of the aorta in vitro.
Energetic and Exergetic Performance Comparison of an Ejector Refrigeration System Using Modern Low GWP Refrigerants
Authors: Mwesigye Aggrey , Dworkin Seth B. 
Published: January 2020

Abstract
In this study, a novel model is used to precisely predict the performance of an ejector refrigeration system utilizing modern environmentally benign working fluids in both the critical and subcritical modes of operation. Energetic and exergetic performance of low global warming potential and non-ozone depleting HCFO and HFO refrigerants: R1233zd(E), R1224yd(Z), R1225ye(Z), hydrocarbon refrigerants: Isobutane and Isopentane and RE245cb2 is compared with that of conventional refrigerants: R141b and R245fa. The model takes the ejector area ratios, generator pressure, and evaporator pressure into account in the determination of the ejector loss coefficients. A program written in Engineering Equation Solver (EES) was used to obtain solutions of the developed mathematical model. In the analysis, ejector area ratios between 6.44 and 12.76, evaporator temperatures between 4 and 16°C, condenser temperatures between 25 and 50°C as well as generator temperatures between 70 and 110°C were used. Results show that Isobutane and R1225ye(Z) have the greatest performance, giving an over 150% increase in the coefficient of performance (COP) compared to R245fa. The increase in the COP with isopentane, RE245cb2, R1224yd(Z) and R1233zd(E) were as high as 22%, 32%, 16% and 14%, respectively at the lowest area ratio. Results further show that the ejector contributes the highest exergy losses (up to 55%, depending on the evaporator, condensing and generator temperatures) compared to the other components. The contribution of the condenser to the total exergy loss is up to 28%, for the generator it is up to 34% and up to 12% for the evaporator. The pump and the throttle valve give values lower than 0.5 and 9%, respectively for all the refrigerants.
Study on Velocity Distribution Estimation Using Blood Pressure Data Based on the Coupled Wave Theory of Elastic Pipes and Fluids
Authors: Tokunaga Takeshi , Mori Koji , Kadowaki Hiroko , Saito Takashi 
Published: January 2020

Abstract
Cardiovascular disease that is one of Non-Communicable Disease accounts for about 25% of death in Japan. Prevention of arteriosclerosis that is a main cause of cardiovascular disease is important. Since an early lesions of arteriosclerosis progress as functional change of an endothelial cell that is uniformly distributed on the luminal surface of a blood vessel, an accurate evaluation of the endothelial cell function is important as prevention of the arteriosclerosis. Although Flow-Mediated Dilation (FMD) is widely used as a diagnosis of the endothelial cell function in clinic, it is an evaluation method that uses a static diameter of a blood vessel. Moreover, it isn’t possible to take into account individual difference of a wall shear stress on the endothelial cell. In previous study, it is found that an evoked hyperemic wall shear stress is a major correlate of %FMD. In order to accurately measure the endothelial cell function, it is necessary to simply assess the hyperemic shear stress during FMD. However, it is difficult to non-invasively measure the hyperemic shear stress on the endothelial cell in clinic. In this study, we focused on a blood pressure data that is obtained non-invasively and formulated a relationship between the pressure and a flow velocity based on the coupled wave theory. And we estimated a hyperemic shear stress by using a blood pressure data that is obtained by a tonometry method in experiment that simulate FMD. As a result of estimating the hyperemic shear stress, it reflected characteristics of blood flow in clinic. It may be necessary to consider the hyperemic pressure fluctuation that is waves including low frequency components. Moreover, the hyperemic pressure fluctuation should not be treated as a waveform that has individually different a static pressure in estimation of the hyperemic wall shear stress.