bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic Characterization of Shape Memory Alloys for Integration With Electronic Packaging
Authors: Mizar Shivananda P. , Pryputniewicz Ryszard J. 
Published: November 2021

Abstract
Integration of Shape Memory Alloys (SMAs) with electronic packaging depends on detailed knowledge of thermomechanical behavior of SMAs. In this paper, thermomechanical behavior of SMAs is studied using a new approach based on Analytical, Computational, and Experimental Solutions (ACES) methodology. More specifically, variation in modulus of elasticity of equiatomic NiTi alloy is studied, as a function of temperature. The results show that the modulus of elasticity of the NiTi alloy studied herein varies from 38 GPa to 72 GPa as the temperature changes from −15°C to 190°C, corresponding to phase transition from martensite to austenite. Comparison of analytical, computational, and experimental results shows good correlation.
Multi-Axial Cyclic and Monotonic Behavior of a 63Sn-37Pb Solder Alloy
Authors: Lim T. Jesse , Lu Wei-Yang 
Published: November 2021

Abstract
In this work, the cyclic and monotonic loading of both pure torsion and uniaxial behavior of 63Sn-37Pb solder alloy are compared. By comparing the monotonic loading, it is shown that the ultimate equivalent stress of both torsion and uniaxial tensile behavior is comparable; and the failure strain in uniaxial tension is considerably less than that of pure torsion. The fatigue life of this solder alloy under the same equivalent strain amplitude for both uniaxial tension-compression and pure torsion are also comparable. These data provide a baseline for investigating the behavior of the solder alloy in the multi-axial stress-strain space.
Analysis of Thermal Stresses in a Layered Circuit Board
Authors: Gerdeen James C. 
Published: November 2021

Abstract
When choosing materials for a printed circuit board (PCB), it appears that a common misconception is that the coefficients of thermal expansion should be matched as closely as possible to minimize the stresses. In this paper it is shown that this is not necessarily true. A one-dimensional thermal stress analysis is considered for a printed circuit board (PCB) with N layers. Bending is neglected and average axial normal stresses and shear stresses are accounted for. It is shown that the solution for the shear stresses between layers can be written in the form of a difference equation (recurrence relation).
For the first example, a two-layer board is considered. The solution leads to a design guideline. If there is a shear stress design limit then based on this a plot can be made to choose the optimum ratio of CTEs for the layers depending upon whether the conduction heat flow q is zero or not and depending upon magnitude of temperature change.. If q = 0, then matching the coefficients of expansion α1 and α2 reduces the stress to zero. However if q is not zero at some times, then a choice of the CTE ratio α1/α2 should be made to keep the stress between the design limits.
For three or more layers with different properties a design optimization scheme can be used to choose values of the coefficients of thermal expansion.
Drag Reduction of the Flow Past a Circular Cylinder in Surfactant Solution
Authors: Ogata Satoshi , Watanabe Keizo 
Published: November 2021

Abstract
The flow around a circular cylinder in surfactant solution was investigated experimentally by measurement of the pressure and velocity profiles in the Reynolds number range 6000 &lt; Re &lt; 50000. The test surfactant solutions were aqueous solutions of Ethoquad O/12 (Lion Co.) at concentrations of 50, 100 and 200 ppm, and sodium salicylate was added as a counterion. It was clarified that the pressure coefficient of surfactant solutions in the range of 10000 &lt; Re &lt; 50000 at the behind of the separation point was larger than that of tap water, and the separation angle increased with concentration of the surfactant solution. The velocity defect in surfactant solutions behind a circular cylinder was smaller than those in tap water. The drag coefficients of a circular cylinder in surfactant solutions were smaller than those of tap water in the range 10000 &lt; Re &lt; 50000, and no drag reduction occurred at Re = 6000. The drag reduction ratio increased with increasing concentration of surfactant solution. The maximum drag reduction ratio was approximately 35%.
The Lagrangian Dynamics of Steady Vortex Breakdown Bubbles
Authors: Sotiropoulos Fotis , Lackey Tahirih C. 
Published: November 2021

Abstract
We study the phase-space bifurcations of a simple dynamical system to elucidate the role of swirl intensity on the complexity of the dynamics of particle paths in steady vortex breakdown bubbles. We show that there is a range of swirl numbers within which very small stationary disturbances superimposed on a steady, axisymmetric, vortex breakdown velocity field could have a profound effect on the Lagrangian dynamics, leading to a rich mixture of regular and chaotic behavior. Sufficiently high swirl intensity, on the other hand, can stabilize the Lagrangian orbits and yield vortex breakdown bubbles with integrable (axisymmetric) dynamics even when the transporting velocity field is not axisymmetric. We support these findings by presenting computational results for the flow in a closed cylinder with a rotating bottom.
Difference in Critical Reynolds Number Between Hagen-Poiseuille and Plane Poiseuille Flows
Authors: Kanda Hidesada 
Published: November 2021

Abstract
For plane Poiseuille flow, results of previous investigations were studied, focusing on experimental data on the critical Reynolds number, the entrance length, and the transition length. Consequently, concerning the natural transition, it was confirmed from the experimental data that (i) the transition occurs in the entrance region, (ii) the critical Reynolds number increases as the contraction ratio in the inlet section increases, and (iii) the minimum critical Reynolds number is obtained when the contraction ratio is the smallest or one, and there is no-shaped entrance or straight parallel plates. Its value exists in the neighborhood of 1300, based on the channel height and the average velocity. Although, for Hagen-Poiseuille flow, the minimum critical Reynolds number is approximately 2000, based on the pipe diameter and the average velocity, there seems to be no significant difference in the transition from laminar to turbulent flow between Hagen-Poiseuille flow and plane Poiseuille flow.
Pulsatile Flow Into a 45-Degree Tube Bifurcation
Authors: Tadjfar M. , Himeno R. 
Published: November 2021

Abstract
In this study, we use numerical simulation to investigate the pulsatile flow into a 45°-tube bifurcation. There is a well-known analytical solution for the pulsatile flow in a straight pipe. However, to study the pulsatile flow into a branched pipe only numerical solution or experimental techniques are available. The unsteady, three-dimensional, incompressible Navier-Stokes equations are solved using a finite volume solver. A time periodic flow is established. As compared to the straight tube flow case, it is found that the introduction of bifurcation changes the periodic flow structure upstream and downstream of the bifurcation. The periodic flow in the forward flow and the reverse flow part of the cycle are very different. The forward flow part of the cycle is a problem of splitting the mother tube flow into the two daughter tubes. The reverse flow part of the cycle is the problem of two jets coming out of the daughter tubes mixing in the mother tube chamber.
Significance of Inertia in Subcompartment Analysis
Authors: Ashley G. K. , Schuh W. E. 
Published: November 2021

Abstract
When simulating quasi-static inter-compartment flow it is currently accepted practice to include fluid inertia effects in the compartments by extending the flow path beyond its geometrical limits. Such an extension simulates inertia by effectively adding mass to the flow path that the pressure differential between the compartments must overcome. In this paper, the effects of flow inertia are investigated by comparing results for two connected compartments using a quasi-static flow approximation that neglects inertia with results from a method of characteristics program that does include inertia. Comparison of simulations employing these methodologies can be used to assess the influence of inertia during inter-compartment flow.
Detailed Simulation of the Cochlea: Recent Progress Using Large Shared Memory Parallel Computers
Authors: Givelberg E. , Bunn J. , Rajan M. 
Published: November 2021

Abstract
We have developed and are refining a detailed three-dimensional computational model of the human cochlea. The model uses the immersed boundary method to calculate the fluid-structure interactions produced in response to incoming sound waves. An accurate cochlear geometry obtained from physical measurements is incorporated. The model includes a detailed and realistic description of the various elastic structures present. Initially, a macro-mechanical computational model was developed for execution on a CRAY T90 at the San Diego Supercomputing Center. This code was ported to the latest generation of shared memory high performance servers from Hewlett Packard. Using compiler generated threads and OpenMP directives, we have achieved a high degree of parallelism in the executable, which has made possible to run several large scale numerical simulation experiments to study the interesting features of the cochlear system. In this paper, we outline the methods, algorithms and software tools that were used to implement and fine tune the code, and discuss some of the simulation results.
Dynamic Analysis of Diesel Engine Common Rail Injection System: Part II — Four-Cylinder Injection System
Authors: Borghi M. , Milani M. , Piraccini M. 
Published: November 2021

Abstract
The paper is aimed at studying the overall dynamic behavior of the Common Rail Injection System actually used on a 4 cylinder industrial Diesel engine.
Firstly, the paper introduces the main characteristics of a lumped and distributed parameters model of the high pressure branch of an actual Common Rail System, and the main hypotheses assumed to model it using a multi-port approach code for the analysis of the dynamic response of hydraulic systems submitted to fast transients.
The model of the Common Rail System is then used to study its dynamic behavior when involved in the handling of the engine injection cycle for medium values of the crankshaft regime and for different pressure levels in the Rail. The analysis is performed applying to the injectors, to the pressure control valve and to the high-pressure pump the control strategies imposed by the Electronic Central Unit (ECU), as actually implemented into an industrial ECU for Diesel engine management.
The model reliability and accuracy are evidenced through a numerical vs. experimental data comparison, mainly in term of rail pressure dynamic behavior.
The analysis successively outlined in the paper allows to state how the hydraulic behavior of the Common Rail System interact with the electro-hydraulic injectors dynamics, and to determine the influence of this interaction on the total injected mass per cycle.
Variable Flow Internal Gear Pump
Authors: Mancò S. , Nervegna N. , Rundo M. 
Published: November 2021

Abstract
A variable flow internal gear pump is a fixed displacement unit where timing can be varied with respect to the gearing to reduce the net outgoing flow from the delivery volume. Usually, in IC engines lubrication, and at high engine speed, a reduction of the net outgoing flow from the pump is achieved via flow recirculation to inlet through a pressure relief valve. This obviously entails a waste of power. Before thinking of variable displacement units an intermediate step worth of consideration is represented by a variable timing yet constant displacement pump. The management of timing can follow different strategies (either in delay or in advance) and a control philosophy may be implemented whereby timing is varied based on attainment of a constant delivery pressure.
The paper, through theoretical analyses, detailed modelling and simulation of the pump unit, of timing and its control, leads to compare possible and feasible alternatives providing solid ground for screening and progressing to the manufacturing of a prototype. These steps as well as test results of the prototype are contrasted with model based predictive simulations.
Design and Control of the Hydraulic Reciprocating Pump
Authors: Guangzheng Jia , Xuanyin Wang 
Published: November 2021

Abstract
The reciprocating pumps are widely used for transporting fluid in oil field. The flow pulsation and pressure fluctuation in the conventional reciprocating pump with short stroke, high speed and simple harmonic motion of piston driven by crank-connecting rod mechanism are inevitable. For reducing the flow and pressure pulsation, a hydraulic reciprocating pump with the GPCM control by means of normal on-off valve is designed. In order to improve the overall pump performances and life span. fault analysis and optimized design of the pump valve are completed. The mathematical model of the asymmetric cylinder system with PCM valve control used in the hydraulic reciprocating pump is built. The digital simulation about the control system is done, and the result shows that the pulsation of pump discharge flow is improved greatly.
Effect of Particle Volume Fraction on the Thermal Conductivity and Mechanical Rigidity of Particle-Laden Polymeric Thermal Interface Material
Authors: Prasher Ravi S. , Koning Paul , Shipley James , Devpura Amit 
Published: November 2021

Abstract
This paper reports the measurement of the thermal conductivity of particle-laden polymeric thermal interface materials for three different particle volume fraction. The experimental data is further compared with the percolation model and effective medium theory. This paper also introduces a method of obtaining the contact resistance between the particles and the polymeric matrix by combination of percolation modeling and experimental data.
We also discuss the dependence of the mechanical response of these particle-laden polymers for different filler or particle loading. A novel mechanical length scale is defined to understand the mechanical response of these materials and is correlated to the viscosity of these materials.
Infrared Thermal Velocimetry
Authors: Chung Jaewon , Shin Youngshik , Petigrew Kenneth , Chapman Peter , Grigoropoulos Costas P. , Greif Ralph 
Published: November 2021

Abstract
Infrared thermal velocimetry is a new technique for the measurement of flow velocity. This non-intrusive technique was used to measure the velocity in a channel. In detail, a pulse of several milliseconds of a 5W CO2 laser generates a transient temperature response in a flowing liquid. Recording the radiative thermal images of the moving heated liquid, permitted measurement of the flow velocity. This method has powerful characteristics; a wide range of velocities may be measured and the applications include MEMS fluidic devices. In this paper, experimental results are obtained from infrared thermal velocimetry for a syringe forced flow. Numerical results for the system are presented and compared with experimental data. Phenomena which are relevant to typical MEMS thermal flow sensors are also discussed.
Temperature Difference Between the Body Core and the Arterial Blood Supplied to the Brain During Hyperthermia or Hypothermia
Authors: Zhu Liang , Bommadevara Maithreyi 
Published: November 2021

Abstract
In this study a theoretical model was developed to evaluate the temperature difference between the body core and the arterial blood supplied to the brain. Several factors including the local blood perfusion rate, blood vessel bifurcation in the neck, and blood vessel pairs on both sides of the neck were considered in the model. The theoretical approach was used to estimate the potential for cooling of blood in the carotid artery on its way to the brain by heat exchange with its countercurrent jugular vein and by the radial heat conduction loss to the cool neck surface. It shows that blood temperature along the common and internal carotid arteries typically decreases up to 0.86°C during hyperthermia. Selectively cooling the neck surface during hypothermia increases the heat loss from the carotid arteries and results in approximately 1.2°C in the carotid arterial temperature. This research could provide indirect evidence of the existence of selective brain cooling (SBC) in humans during hyperthermia. The simulated results can also be used to evaluate the feasibility of lowering brain temperature effectively by selectively cooling the head and neck surface during hypothermia treatment for brain injury or multiple sclerosis.
Portable Fluorometry for Kinetics Applications
Authors: Venkatapathi Murugesan , Lee Charles Y. 
Published: November 2021

Abstract
With the current explosion of fluorescent indicators in biotechnology, there is a need for new devices to take advantage of these developments. Most fluorometers are benchtop devices and are limited in temperature control and measurement vessels. Under cell culture conditions, these restrictions limit fluorometric experimental design. A portable fluorometer has been developed that allows fluorescent measurements under cell culture and various environmental conditions. The design of the fluorometer takes advantage of dichroic mirrors to excite and measure from the same surface and is portable to conduct kinetics experiments in incubators and refrigerators.
To test the new device, fluorescence experiments were performed to determine conversion of hydroethidine (HE) to ethidium bromide (EB), which is facilitated by reactive oxygen species. Experiments were performed at room temperature and 4°C. One half ml (at 32μM) of HE at room temperature required 80 ± 3mins (mean ± S.D) for complete oxidation. Average slope of the curve was 1.04 ± 0.05 % oxidation /min. At 4°C, the reaction times were 170± 5 mins. Average slope was 0.48 ±0.03% of oxidation/min. Experiments to determine sensitivity to concentrations were performed with comparisons to a benchtop fluorometer (Hitachi 2500). Measurement by the benchtop fluorometer read 100± 6, 33± 4, 33± 4% at concentrations of 10X, 1X, and 0.1X of the working solution respectively. For the portable fluorometer, comparable concentrations had readings of 100±2, 42.2±2.0, 24.7±2.0%, respectively. This device shows both the capabilities to distinguish kinetics at different temperatures and sensitivity to concentration differences.
Transfer Matrix Formulation With Optical Penetration for Axisymmetric Thermoelastic Wave Propagation in Films
Authors: Li Chen , Lin Jiadao , Cetinkaya Cetin 
Published: November 2021

Abstract
Using Laplace and Hankel integral transforms in time and the radial coordinate, a fully-coupled thermoelastic formulation based on the equation of motion and heat equation is developed to study the effects of axial optical penetration on axisymmetric wave propagation in thermoelastic layers and/or layered structures. It is demonstrated that the optical penetration has no effect on the entries of the sextic transfer matrix, however it introduces an equivalent forcing term for all state variables for both surfaces of a thermoelastic layer as opposed to the surface heating case in which the heating effect is localized in the heating volume (the thermal skin). The thickness of thermal skin depends on the light intensity modulation frequency while the optical penetration typically depends only on the wavelength of the light. This additional forcing vector is a function of the light intensity modulation frequency, the radial wave number, penetration decay rate, as well as thermoelastic material properties. Complexities in wavefields due to the nature of the forcing term are demonstrated and discussed. A thin copper layer with hypothetical penetration properties is considered for the demonstration of the current formulation.
The Investigation of Distorted and Enhanced Inlet Flow Influence on the Performance of a Centrifugal Compressor Stage
Authors: Kim Yunbae , Engeda Abraham , Aungier Ron , Direnzi Greg 
Published: November 2021

Abstract
The performance of a centrifugal compressor can be seriously affected by inlet flow distortions due to the unsatisfactory nature of the inlet configuration and the resulting inlet flow structure.
In the previous work, experimental tests were carried out for the comparison of a centrifugal compressor stage performance with two different inlet configurations: one of which was a straight pipe with constant cross-sectional area as an ideal model and the other is a 90-degree curved pipe with nozzle shape as an actual model. The comparative test results indicated significant compressor stage performance difference between the two different inlet configurations.
In addition, the numerical simulation part of the previous work clearly showed that the inlet flow distortion is caused by the pressure driven secondary flow developed in the curved section in the case of the bend inlet, resulting in locally concentrated incidence at the impeller inlet and thus the compressor stage performance degradation. An improved inlet model with the design method has been proposed based on the comparisons of the designated flow properties.
In the present work, further numerical simulations on the compressor stage including the impeller and the diffuser with three different inlets are carried out to investigate the performance behavior of the compressor exposed to different inlet configurations. The three different inlet systems include the original bend inlet as well as the proposed inlet model based on the developed design method.
Since the flow from the bend inlet is not axisymmetric due to the circumferential and radial distortion on the cross-section, the impeller and the diffuser are modeled with fully 360-degree passages, which accommodates the inlet flow distortion and the impeller-diffuser interaction influence on the entire flow passage of the compressor. The stage performance with the different inlet systems are evaluated and compared with the previous experimental result. The diffuser performance and the flow properties in the vaneless region are compared among those inlet models. The proposed inlet system indicated the benefit of performance improvement over the original inlet system.