bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a Space-Rated Proton Exchange Membrane Fuel Cell Powerplant
Authors: Hoffman William C. , Vasquez Arturo , Lazaroff Scott M. , Downey Michael G. 
Published: December 2021

Abstract
Power systems for human spacecraft have historically included fuel cells due to the superior energy density they offer over battery systems depending on mission length and power consumption. As space exploration focuses on the evolution of reusable spacecraft and also considers planetary exploration power system requirements, fuel cells continue to be a factor in the potential system solutions.
Substantial efforts are currently underway in the commercial markets to produce a proton exchange membrane (PEM) fuel cell capable of meeting terrestrial power demands in residential, commercial, and automotive applications. However, there are unique characteristics of spaceflight that can only be dealt with through specific engineering solutions.
From a systems perspective, removing product water from the cell stack and separating the water from the oxygen gas stream in a PEM fuel cell are two critical functions. One method to remove product water from the cell stack and subsequently separate the product water from the oxygen involves using components with no moving parts — a gas ejector and membrane gas-water separator. Tests are currently underway at the Johnson Space Center to evaluate and refine gas ejectors to satisfy the fuel cell requirement to circulate cathode reactant gas (oxygen) at 1 to 3 times the stoichiometric consumption flow rates in order to adequately remove water from the cathode. A gas-water separator utilizing hydrophobic and hydrophilic materials is also being evaluated to perform the function of separating the water from the oxygen gas stream. Analytical and experimental evaluations are continuing on the fuel cell components, including cell stacks, with the goal of developing a comprehensive design basis for a fuel cell powerplant capable of delivering 20 kW at approximately 28 VDC. Through the select critical component refinement in work at the Johnson Space Center, engineers are improving the readiness and reducing the technical and cost risks of a PEM fuel cell capable of operating in a space environment.
Three Phases of Applications of Thermodynamics to Process System Synthesis
Authors: Ishida Masaru 
Published: December 2021

Abstract
Process system synthesis is a very creative work. It has been thought that only experts can create a new system. In this paper, we discuss the procedure for process system synthesis systematically and show that applications of thermodynamics are possible in three different phases of process system synthesis.
(1) Concept generation
(2) Creation of functional structures
(3) Effective utilization of energy
The roles of each phase in the course of process system synthesis are discussed and the key tools for each stage are presented.
Thermodynamic Analysis of Various Heat Generation Methods
Authors: Smyk Adam , Portacha Józef , Fiszdon Jerzy K. 
Published: December 2021

Abstract
Various methods of heat generation including cogeneration, district heating, and several types of individual heaters are considered together with a variety of fuels. Performance characteristics for these systems, including fuel use, and thermal and exergetic efficiency are evaluated. Specifically, a complex thermodynamic model of the cogeneration system is presented. In this model the conditions of the surroundings vary with the surroundings temperature. Calculated efficiencies include losses in all components from the sources to the consumer (i.e. in the boiler, the turbine, the heat exchangers, and the whole transmitting network). Exergetic efficiencies vary from as low as 3% for electric heaters to more than 14% for large cogeneration plants. This result places the cogeneration systems as the most effective technology for heating. This technology produces the biggest fuel savings (four times less than for electric heating), and is therefore more environmentally friendly.
Nontraditional Striker Impact
Authors: Goldsmith Werner 
Published: December 2021

Abstract
More than 95% of published investigations involving projectile collisions can be classified as “standard”, defined as the orthogonal impact of purely translating strikers on stationary solid targets; non-standard impacts are all other cases that invariably occur in the field in one form or another. Impingement of projectiles has been studied since the 1700’s; for the first 150 years, only empirical results were obtained. Since about 1890, semi-empirical and quasi-rational approaches have been developed. This century has seen the enormous growth of phenomenological modeling, computational analysis — which provides for both spatial and temporal discretization and relies on material behavior description, including failure — and extended test methodologies due to the vast improvement of observation and measuring devices. Basically, whether standard or otherwise, impingement of a striker on a target can result in embedment, perforation or ricochet.
Lamb Wave Inspection of Concrete Beams
Authors: Jung Y. C. , Kundu T. , Ehsani M. 
Published: December 2021

Abstract
The feasibility of detecting defects in concrete beams using Lamb waves is investigated in this paper. The traditional ultrasonic methods for inspecting defects in concrete use the reflection and scattering of longitudinal waves by internal defects. Signal amplitude and time of flight measurements provide information about the internal defects in concrete. However, these methods are time consuming and often fail to detect honeycombs, closed cracks and small defects. In this paper the potential of the Lamb wave technique to detect those defects in large concrete beams is investigated. The Lamb wave technique is found to be reliable for detecting such defects in concrete beams.
Application of Joint-Time Frequency Analysis Methods for Nondestructive Evaluation
Authors: Nam Ki-Woo , Lee Kun-Chan , Oh Jeong-Hwan 
Published: December 2021

Abstract
Application of signal processing techniques to nondestructive evaluation (NDE) in general and acoustic emission (AE) studies in particular has become a standard tool in determining the frequency characteristics of the signals and relating these characteristics to the integrity of the structure under consideration. Recent studies have shown that the frequency characteristics of ultrasonic signals from evolving damage during cyclic (fatigue) and dynamic loads change with time; in other words, the signals are nonstationary, and that these changes can be related to the nature of the damage taking place during loading. A joint time-frequency analysis such as Short Time Fourier Transform (STFT) and Wigner-Ville distribution (WVD), can in principle be used to determine the time dependent frequency characteristics of nonstationary signals in presence of background noise. In this study these techniques are applied to analyze AE signals from fatigue crack propagation in 5083 aluminum alloys and ultrasonic signals in degraded austenitic 316 stainless steels, to study the evolution of damage in these materials. It is demonstrated that the nonstationary characteristics of both AE and ultrasonic signals could be analyzed effectively by these methods. STFT was found to be more effective in analyzing AE signals, and WVD was more effective for analyzing the attenuation and frequency characteristics of degraded materials through ultrasonics. It is indicated that the time-frequency analysis methods should also be useful in evaluating crack propagation and final fracture process resulting from various damages and defects in structural members.
Stiffness and Strength Properties for Basic Sandwich Material Core Types
Authors: Kim Beomkeun , Christensen Richard M. 
Published: December 2021

Abstract
Three basic core material types for sandwich structure applications are studied. The three two-dimensional pattern types are: honeycomb, triangular cells, and a new configuration involving star type cells. The specific critical properties of stiffness and strength type are identified and studied, both theoretically and experimentally.
Measure of Test Fidelity of Analytical Crash Pulses
Authors: Riesner M. , Low E. K. 
Published: December 2021

Abstract
In this paper, the test fidelity measure of analytical crash pulses is defined by the magnitude of an energy-momentum, (E-M), metric distance of an analytical pulse with respect to a reference, (test), pulse. The energy-momentum metric is defined and applied to calculate (E-M) metric distance of three analytical crash pulses from each other and from the test pulse. The pulses are for 35 mph. 90° rigid barrier front crash event for an identical vehicle. The three analytical pulses are generated by finite element analysis, FEA, using three different finite element models, FEM, and different solution techniques. The (E-M) metric distance of the pulses is shown to be a measure of the test fidelity of the analytical pulses. The test fidelity of the analytical pulses is defined as the ability of an analytical pulse to predict the occupant injury predictions close to the ones measured in the actual hardware test. It is shown that the crash pulse with the smallest (E-M) metric distance from the test will yield the occupant injury predictions closest to the ones yielded by the test. The test fidelity of analytical pulse will, in turn, allow to evaluate the ability of an FEM to produce high fidelity crash pulses. It is shown that high test fidelity crash pulses can be obtained by using relatively simple finite element models.
Crashworthiness Studies of Locomotive Wide Nose Short Hood Designs
Authors: Tyrell David C. , Martinez Eloy E. , Wierzbicki Tomasz 
Published: December 2021

Abstract
This paper investigates the parameters that influence the structural response of typical wide nose locomotive short hoods involved in offset collisions. This accident scenario was chosen based upon the railway collision that occurred in Selma, North Carolina, on May 16, 1994. A raised overhanging intermodal trailer on a freight car struck the front of the oncoming passenger locomotive. The objective of the study is to determine the current baseline level of crashworthiness of locomotive hood structures and the potential effectiveness of stronger corner structures. The key issues addressed are: degree of overlap, material and thickness combinations, obliquity, and crush response dependence on initial impacting speed. For a raised offset collision where the intruding body is far away from any support structures, an analytical expression is developed to predict the mean crush force. Comparisons of the results with finite element calculation are favorable. The scenarios involving obliquity, and different initial impacting speeds are investigated using non-linear large deformation finite element analyses. Key results are: obliquity has little effect on the mean crush force for short penetration distances; increased material thickness improves crashworthiness performance; initial impacting speed does not dramatically alter mean crush loads predicted for large offsets away from supports; and the distances from supporting structures have a significant effect of the predicted mode of failure and hence predicted mean crush loads. The results of the study show that it is possible to dramatically increase the crashworthiness responses of short hood structures with minor increases in weight while staying within the original design volume envelope.
Convective Heat Transfer at Minimum Fluidization Velocity for Gas-Solid Fluidized Beds
Authors: Sharma Kal R. 
Published: December 2021

Abstract
Experimentally measured values for the minimum fluidization velocities and time averaged local surface heat transfer coefficients are provided for 16 different cases of fluidizing conditions for gas-solid dense fluidized beds. Semi-empirical Correlations for the minimum fluidization velocity and the heat transfer coefficient at minimum fluidization velocities are provided. The implications of the Peclet number dependence in terms of diffusion and convection is discussed.
Determination of Air-Water Interfacial Area for Drainage and Imbibition in Unsaturated Porous Media
Authors: Schaefer Charles E. , DiCarlo David A. , Roberts Paul V. , Blunt Martin J. 
Published: December 2021

Abstract
A new experimental method was developed to measure air-water interfacial area as a function of capillary pressure and water saturation in unsaturated porous media. The surfactant sodium dodecyl benzene sulfonate (SDBS) was used in equilibrium column adsorption experiments to determine the air-water interfacial area for water saturations (ml water/ml pore space) ranging from 0.05 to 1.0, and pressures ranging from 0 to 20 cm of water. A comparison was made between columns which were equilibrated under gravity drainage, versus columns equilibrated under secondary imbibition. Gravity drainage experiments showed the air-water interfacial area decreased linearly with saturation, while imbibition experiments showed a more complex non-monotonic relation to the saturation.
The Influence of Boundary Condition on Solidification of Binary Solution in Rectangular Cavity
Authors: Pradeep N. , Kang H. J. , Lin C. X. , Ebadian M. A. 
Published: December 2021

Abstract
The solidification of a binary mixture of ammonium chloride and water flow cooling in rectangular cavities was investigated experimentally under different boundary conditions. Two cavities measuring 63.5 × 180 × 165 mm and 76 × 120 × 96 mm were employed in this study. For the first cavity, its three surfaces (i.e., two side surfaces and one bottom surface) were cooled. For the second cavity, however, only two side surfaces were cooled (i.e., the bottom surface was adiabatic). The influence of the change of boundary was studied. All investigations were carried out in the surface temperature range from −15 to −30°C under a constant refrigerant temperature of −22°C. The effect of cooling boundary condition had a great effect on the heat transfer process during the solidification process. The advanced Particle Image Velocimetry (PIV) technique was used to catch the velocity profiles during the solidification process.
The Effect of Particle Inlet Conditions on FCC Riser Hydrodynamics and Product Yields
Authors: Chang S. L. , Golchert B. , Lottes S. A. , Zhou C. Q. , Huntsinger A. , Petrick M. 
Published: December 2021

Abstract
Essential to today’s modern refineries and the gasoline production process are fluidized catalytic cracking units. By using a computational fluid dynamics (CFD) code developed at Argonne National Laboratory to simulate the riser, parametric and sensitivity studies were performed to determine the effect of catalyst inlet conditions on the riser hydrodynamics and on the product yields. Simulations were created on the basis of a general riser configuration and operating conditions. The results of this work are indications of riser operating conditions that will maximize specific product yields. The CFD code is a three-dimensional, multiphase, turbulent, reacting flow code with phenomenological models for particle-solid interactions, droplet evaporation, and chemical kinetics. The code has been validated against pressure, particle loading, and product yield measurements. After validation of the code, parametric studies were performed on various parameters such as the injection velocity of the catalyst, the angle of injection, and the particle size distribution. The results indicate that good mixing of the catalyst particles with the oil droplets produces a high degree of cracking in the riser.
Computational and Experimental Analysis of a Meso-Scale Heat Exchanger
Authors: Sheu J. C. , Giridharan M. G. , Hong S. H. , Shekarriz R. , Call C. 
Published: December 2021

Abstract
The main objective of this study is to develop an efficient meso-scale thermo-catalytic air purification system for battlefield applications. In this system, heated air is passed through a catalytic reactor to destroy toxic materials. The main constraints in designing this system are size, weight and fuel/power consumption. A successful design of this type of purification system depends to a large extent on the efficiency and performance of the heat exchanger. As a first step, a heat exchanger system that consists of several units of planar counter flow heat exchangers stacked on top of each other has been designed and fabricated. A CFD (Computational Fluid Dynamics) model has been used to understand the flow and heat transfer characteristics as well as to predict the effectiveness of the heat exchanger. A series of experiments have been performed to collect data to validate the CFD results. It will be shown that the data for temperature and effectiveness are in agreement with CFD predictions. Parametric simulations have also been performed to evaluate the heat exchanger performance as functions of geometric and operating conditions. The results indicate that axial conduction in the exchanger plate and the thermal boundary layer film resistance are the limiting factors in the heat exchanger performance.
Multigrid Numerical Solutions of Non-Isothermal Laminar Recirculating Flows
Authors: de Lemos Marcelo J. S. , Mesquita Maximilian S. 
Published: December 2021

Abstract
The present work investigates the efficiency of the multigrid numerical method applied to solve two-dimensional laminar velocity and temperature fields inside a rectangular domain. Numerical analysis is based on the finite volume discretization scheme applied to structured orthogonal regular meshes. Performance of the correction storage (CS) multigrid algorithm is compared for different inlet Reynolds number (Rein) and number of grids. Up to four grids were used for both V- and W-cycles. Simultaneous and uncoupled temperature-velocity solution schemes were also applied. Advantages in using more than one grid is discussed. Results further indicate an increase in the computational effort for higher Rein and an optimal number of relaxation sweeps for both V- and W-cycles.
Three Dimensional Reconstruction From Limited Projection Data Using a Novel MART Algorithm
Authors: Mishra Debasish , Muralidhar K. , Munshi P. 
Published: December 2021

Abstract
The present work is concerned with the development of a robust three dimensional reconstruction algorithm for applications involving tomography. In an earlier study it was shown that among the ART family of algorithms the multiplicative algebraic reconstruction algorithm (MART) was the most appropriate for tomographic reconstruction. In the present work, the MART algorithm has been extended so that (a) its performance is acceptable over a wider range of relaxation factors, (b) the time requirement for convergence to a solution is lower and (c) its performance is less sensitive to noise in the projection data. Two applications have been considered for evaluating the proposed algorithms namely a circular region with holes and experimental data recorded in a differentially heated fluid layer using an interferometer. The algorithms proposed are seen to be clearly an improvement over those presently available.
Measurement of the Thermal and Velocity Fields in the Liquid Phase of Turbulent Subcooled Bubbly Boiling Flow
Authors: Roy R. P. , Kang S. , Zarate J. A. 
Published: December 2021

Abstract
To investigate the thermal and velocity fields in the liquid phase of turbulent subcooled boiling flow, local measurements were made in the bubbly regime. The boiling flow, of Refrigerant-113, was created in a vertical annular channel whose inner wall was heated. The technique involves the simultaneous use of a two-component laser Doppler Velocimeter (LDV) for measuring the velocity field, and a fast-response cold-wire for measuring the temperature field. The LDV measuring volume (m.v.) dimensions in the liquid were: 290 microns spanwise length × 55 microns diameter. The 3.8 micron diameter tungsten cold-wire had an active length of 300 microns and was placed 250 microns downstream of the center of the LDV m.v. The cold-wire in conjunction with an active phase-lead compensation circuit had a temperature response time constant of 0.3±0.02 ms in the liquid flow.
To validate the measurement technique, the velocity and thermal fields were first measured in heated single-phase liquid flow in the same channel and compared with the corresponding computed fields. Selected results are presented. Next, measurements in boiling flow at one experimental condition are presented and their intended use in multidimensional two-fluid modeling of the flow is briefly discussed.
Design Competitions Come to Heat Transfer
Authors: Somerton Craig W. , Bénard Andre , Genik Laura J. , Hoke Paul , Schroeder Joseph , Vance Robert 
Published: December 2021

Abstract
Five different design project competitions focused on heat transfer processes are presented. The projects are design, build, test, and report in nature. These elements are described within the paper for each project. A semester ending design competition is held where the student teams present their devices and their performance is evaluated.
Explosion Hazard Analysis for the Brookhaven National Laboratory Relativistic Heavy Ion Collider PHENIX Detector
Authors: Ciccarelli Gaby 
Published: December 2021

Abstract
Currently under construction at Brookhaven National Laboratory (BNL) is a large 3.8 km in circumference collider called the Relativistic Heavy Ion Collider (RHIC). The collider is capable of creating thousands of head-on collisions between beams of heavy ions, e.g., gold, or polarized protons traveling at nearly the speed of light Four experiments built along RHIC’s underground ring will measure the particles unleashed when the beams collide. This study deals with the PHENIX Detector which roughly fills an Experimental Hall with a floor area of 18.6 m by 15.8 m and a height of 14.3 m. The RHIC tunnel connects to the Experimental Hall through two opposite walls. The large tunnel openings are almost completely obstructed by massive steel plates which are part of the PHENIX Muon detector system. The Experimental Hall walls are all fixed except for one which is constructed from 1.7 m thick concrete blocks covering an opening which is 18 m wide by 14.0 m high. This block wall has a plug door which is designed to be unstacked so that large PHENIX detector systems can be transferred from the Experimental Hall into the adjacent Assembly Hall when required.
The detector consists of several systems, each with its own role in detecting subatomic particles. Combustible gases such as ethane, isobutane, and methane are used in several of the detector systems. In particular, one of the systems called the Ring Imaging Cherenkov Detector (RICH) uses 80 m3 of pure ethane in two welded aluminum frames each with two large 0.127 mm thick aluminized KAPTON windows. The ethane gas is maintained at a pressure of a fraction of an inch of water above the ambient pressure. The work reported here deals with a safety analysis for a hypothetical accident scenario whereby the RICH windows are damaged and all the ethane inventory is released into the Experimental Hall, mixed with the ambient air and ignited. The objective of the analysis was to determine the scope of damage to the experiment and danger to personnel under various accident scenarios involving the extent of ethane gas release, the degree of mixing with ambient air and the mode of combustion. If all the ethane is assumed to be released and allowed to mix with the entire volume of air contained within the Experimental Hall, the calculations show that ignition of this mixture would not result in the collapse of the block wall.