bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Functional Failure Analysis Method of Identifying and Mitigating Spurious System Emissions From a System of Interest in a System of Systems
Authors: Van Bossuyt Douglas L. , Arlitt Ryan M. 
Published: April 2020

Abstract
Increasingly tight coupling and heavy connectedness in system of systems (SoS) present new problems for systems’ designers and engineers. While the failure of one system within a loosely coupled SoS may produce little collateral damage beyond a loss in SoS capability, a highly interconnected SoS can experience significant damage when one member system fails in an unanticipated way. It is therefore important to develop systems that are “good neighbors” with the other systems in an SoS by failing in ways that do not further degrade an SoS’s ability to complete its mission. This paper presents a method to (1) analyze a system of interest (SoI) for potentially harmful spurious system emissions (failure flows that exit the SoI’s system boundary and may cause failure initiating events in other systems within the SoS) and (2) choose mitigation strategies that provide the best return on investment for the SoS. The method is intended for use during the system architecture phase of the system design process when functional architectures are being developed, and analysis of alternatives and trade-off studies are being conducted2.
Efficient Singularity-Free Workspace Approximations Using Sum-of-Squares Programming
Authors: Sirichotiyakul Wankun , Patoglu Volkan , Satici Aykut C. 
Published: April 2020

Abstract
In this paper, we provide a general framework to determine inner and outer approximations to the singularity-free workspace of fully actuated robotic manipulators, subject to Type-I and Type-II singularities. This framework utilizes the sum-of-squares optimization technique, which is numerically implemented by semidefinite programming. In order to apply the sum-of-squares optimization technique, we convert the trigonometric functions in the kinematics of the manipulator to polynomial functions with an additional constraint. We define two quadratic forms, describing two ellipsoids, whose volumes are optimized to yield inner and outer approximations of the singularity-free workspace.
Function Modeling: A Modeling Behavior Analysis of Pause Patterns
Authors: Patel Apurva , Kramer William S. , Flynn Michelle , Summers Joshua D. , Shuffler Marissa L. 
Published: April 2020

AbstractThis paper presents a behavior-based protocol study conducted with mechanical engineering students, where the participants developed function–structure models for a novel design problem. A modeling activity video was recorded for each participant and coded using a protocol analysis that captured the modeling sequence, actions, and elements. Pauses in the modeling process were analyzed to identify patterns based on pause time and frequency, the distribution of pauses over the modeling activity, and events preceding and following the pauses. In this study, a pause is characterized as an interruption in the modeling process lasting at least 2 s. Participants were found to spend an average of 38% of the modeling time in pauses, with more of it being allotted to the middle of the modeling activity and less toward the start and end. Three pause types are defined (short, intermediate, and long pauses) based on an analysis of pause lengths, which are then used to analyze events before and after pauses. Participants added elements to the model more frequently, compared to editing and deleting elements. Longer pauses were observed before participants before elements are removed from the model, whereas editing was done more frequently after shorter pauses. Several modeling element pairs are identified that are infrequently separated by pauses, such as the “edge” and “edge text” pair, suggesting that the designer thinks about these as paired elements rather than distinct elements. Limitations of the research methods are discussed, and finally, new research questions are identified as continuing work for this research.
Investigation of Viability to Replace Draft Animals With All-Wheel-Drive Motorcycles on Small Farms
Authors: Diaz Lankenau Guillermo F. , Winter V Amos G. 
Published: April 2020

Abstract
This paper describes the design, functional testing, and user feedback for a tractor specialized for small farms in low-resource settings, particularly India. The presented tractor is unique in its ability to compete with draft animals’ physical dimensions, pulling performance, and sale price, while retaining key tractor advantages such as compatibility with modern tools, low maintenance costs, and reduced drudgery. This tractor features motorcycle-like controls and seating, inline drive wheels, stabilization via an outrigger arm or a specially developed, novel balance board attachment, and the ability to attach implements ahead or behind the rear axle. The design was created to address unmet farmer requirements identified during interviews with Indian farming stakeholders. A prototype of the tractor demonstrated the completion of key farming operations in a Massachusetts farm where expert user feedback was obtained. In-person interviews on the tractor’s usefulness were then conducted with 24 small and marginal Indian farmers in Karnataka, Gujarat, and Tamil Nadu. The tractor was described to the farmers with help of pictures, videos, and local experts. Farmers generally reported that the prototype tractor would meet their needs and suggested being willing to purchase the vehicle for 123,000 INR, about 22% higher than the price target for which the tractor was designed. The interviewed farmers reported an average likelihood of 4.8/5 that they would use the vehicle for planting, inter-cultivation, and spraying, and an average likelihood of 3.8/5 that they would use the tractor for primary or secondary tillage.
Effects of Weirs on the Resin Transfer Molding Process
Authors: D’Silva Kiran M. , Pang Su-Seng , Schulz Kurt C. 
Published: April 2020

Abstract
Low mold filling time and improper fiber wetting are the main problems faced by the manufacturers applying the Resin Transfer Molding (RTM) process. The objective of this work was to minimize these problems and to study the effect of weirs on the RTM process. A mold was designed such that the lower mold plate contains two weirs, one at the resin inlet port and the other at the outlet port. The purpose of adding the weirs is to provide a continuous inlet stream near the resin inlet port and to cause backpressure near the outlet port to induce complete mold filling. Laminated plates were prepared using glass fibers and epoxy resin (combination of EPON resin-862 and curing agent W). The test parameters investigated, such as void contents, dry spots and mold filling time, were compared with those of samples that were prepared without the use of weirs. It was found that the presence of weirs resulted in significant elimination of dry spots, minimization of void contents and a reduction in mold filling time. As a result, the cost required to manufacture composite parts can be reduced by the use of weirs.
In addition to the experimental investigation, a computer simulation (using LCMFLOT software) of resin flow inside the mold cavity was conducted. Many simulations were run in order to optimize the height and shape of the weir. Rectangular weirs of height 2.54 mm showed minimum mold fill time. It was found that the results obtained from the experimental work and flow simulations are in good agreement. Based on this work, it is evident that complex parts can be produced in less cycle time if weirs are positioned at appropriate locations.
Influence of Temperature Variation on the Post Impact Strength of Glass Fiber Composite Materials
Authors: Ibekwe Samuel I. , Mensah Patrick F. , Li Guoqiang , Pang Su-Seng 
Published: April 2020

Abstract
Glass Fiber Composite laminates were subjected to low velocity impact at 2 m/s using a semi-hemispherical drop tower tup. Impact damage were observed and recorded over a wide range of temperatures. Of particular interest is the post impact strength at these test temperatures. The effect of temperature variation on the impact damages and on the residual compressive buckling strength and elastic modulus is evaluated based on the test results.
Computing CHEMKIN Sensitivities Using Complex Variables
Authors: Butuk Nelson , Pemba JeanPaul 
Published: April 2020

Abstract
This paper discusses an accurate numerical approach of computing the Jacobian Matrix for the calculation of low dimensional manifolds for kinetic chemical mechanism reduction. The approach is suitable for numerical computations of large scale problems and is more accurate than the finite difference approach of computing Jacobians. The method is demonstrated via a highly stiff reaction mechanism for the synthesis of Bromide acid and a H2/Air mechanism using a modified CHEMKIN package. The Bromide mechanism consisted of five species participating in six elementary chemical reactions and the H2/Air mechanism consisted of 11 species and 23 reactions. In both cases it is shown that the method is superior to the finite difference approach of computing derivatives with an arbitrary computational step size, h.
A Numerical and Experimental Study of a Microthruster Performance
Authors: Choudhuri Ahsan R. , Baird Benjamin , Gollahalli S. R. 
Published: April 2020

Abstract
Performance and flow characteristics of a conical microthruster operated in cold thruster mode are presented. Nitrogen, Argon and Carbon dioxide were used as the medium. The performance parameters (specific impulse, impulse efficiency, thrust coefficient and characteristic velocity) are measured. The chamber pressure was varied from 2.8 bar to 12 bar. It is found that the high viscous loss severely degrades the performance of the thruster at a pressure below 5 bar. However, the mass flow remains unaffected even at a low pressure. The computed Mach number shows that at low pressures flow separates earlier. The schlieren photographs show the flow development inside the thruster at different pressures. Interestingly, a highly asymmetric flow field exists in the nozzle expansion section. Row perturbation effects cause the flow to separate from the upper wall and to remain attached with lower wall.
Thermal Analysis of Curing Process of Epoxy Prepreg
Authors: Sun Liangfeng , Sterling Arthur M. , Pang Su-Seng , Negulescu Ioan I. , Stubblefield Michael A. 
Published: April 2020

Abstract
The curing process of epoxy prepreg was studied by means of Differential Scanning Calorimeter. The dynamic, isothermal, and combinations of dynamic and isothermal measurements were done over selected temperature ranges and isothermal cure temperatures. The heats of reaction for dynamic and isothermal cure were determined. The results show that the heat of isothermal-cure reaction increased with the increment of temperature. The degree of cure was calculated from the heat of isothermal-cure reaction. The complete cure reaction could be achieved at 220 °C within the very short cure time. The changes of cure rate with time were given for the studied isothermal cure temperatures. To simulate the relationship between the cure rate and degree of cure, the autocatalytic model was used and the four parameters were calculated. Except in the late stage of cure reaction, the model agrees well with the experimental data, especially at high temperatures. To account for the effect of diffusion on the cure rate, a diffusion factor was introduced into the model. The modified model greatly improved the predicated data at the late stage of cure reaction.
Experimental Study of Low Liquid Loading Gas-Liquid Flow in Near-Horizontal Pipes
Authors: Olive Nicolas R. , Zhang Hong-Quan , Redus Clifford L. , Brill James P. 
Published: April 2020

Abstract
Gas-liquid two-phase flow exists extensively in the transportation of hydrocarbon fluids. A more precise prediction of liquid holdup in near-horizontal, wet-gas pipelines is needed in order to better predict pressure drop and size downstream processing facilities. The most important parameters are pipe geometry (pipe diameter and orientation), physical properties of the gas and liquid (density, viscosity and surface tension) and flow conditions (velocity, temperature and pressure). Stratified flow and annular flow are the two flow patterns observed most often in near-horizontal pipelines under low liquid loading conditions. Low liquid loading is commonly referred to as cases in which liquid loading is less than 1,100 m3/MMm3 (200 bbl/MMscf).
A previous study by Meng [1] was carried out on a new low liquid loading flow loop. A transparent test section (50.8-mm inner diameter and 19-m long) could be inclined within ± 2° from the horizontal. Mineral oil was used as the liquid and air was used as the gas phase. A surprising phenomenon was observed with air-oil flow; at high gas velocities (annular flow), liquid film flow rate, liquid holdup and pressure gradient decreased as liquid velocity increased.
Low liquid loading gas-liquid two-phase flow in near-horizontal pipes was studied for air-water flow in the present study, in order to investigate the effects of the liquid properties on flow characteristics. This study was carried out on the same 2-in. ID flow loop used by Meng. The measured parameters included gas flow rate, liquid flow rate, pressure, differential pressure, temperature, liquid holdup, pipe wetted perimeter, liquid film flow rate, droplet entrainment fraction and droplet deposition rate. A new phenomenon was observed with air-water flow at low superficial velocities and with a liquid loading larger than 600 m3/MMm3. The liquid holdup increased as gas superficial velocity increased.
A Web-Based Expert System for Computer-Aided Manufacturing Parameter Setting
Authors: Tai David C. T. , Wu Shu-hui , Chen Jacob J. G. 
Published: April 2020

Abstract
Numerical Control (NC) machining is an important process for modern automation. Lots of Computer-aided Manufacturing (CAM) systems are widely used in NC machining. Most of these kinds of software are able to generate the NC codes automatically and import these codes to the control unit of a NC machine center. Parameter setting for generating the NC codes is the key procedure for post process of the CAM system. The paper employs Java language to develop an expert system delivered via the web. Java-swing components in Java Foundation Class (JFC) are used for designing the query interface and displaying the query results. Some critical query information such as working material, cutting tool material and tool diameter is imported to the system. Two critical expertise parameters, tool spindle speed and feed rate, for post process of a computer-aided manufacturing system which generates the NC codes will be provided.
An Integrated Study for a Condensate Reservoir to Optimize Gas Production
Authors: Kasap Ekrem , Wang James 
Published: April 2020

Abstract
Q2-Sand of MC486, Gulf Coast is a mature low yield, condensate reservoir. The two issues to be resolved were 1) in-fill drilling requirements to optimize the production against early watering out of the existing wells, and 2) compressor schedules and capacities once the pressure is lower than the platform requirements. A new numerical flow model based on a geological, log, seismic, and production data was needed to resolve the issues. A multi-disciplinary characterization study to formulate final re-development and production optimization schemes is undertaken.
The static reservoir model was built from the 3-D seismic interpretations for the upper and the lower horizons. Thickness variations across the field and by horizons were estimated from thickness-amplitude correlations. Saturation, porosity, and net-to-gross ratio values were obtained from the core and log data. Variable directional permeabilities were calculated by a flow based upscaling technique using net-to-gross ratios and clean-sand and shale permeabilities. The compositional characteristics of the production were simulated with a fully compositional flow model.
The G&G model delineated Northern Prospect and the Main Reservoir. Both of these features were included into the numerical flow model along with the partially active aquifer that separates them. The numerical model was initialized and calibrated to the historical production data at the six wells. The current average pressure of the Northern Prospect is obtained. An additional aquifer support for the upper and lower sands was resolved, and the cross-flow spots between them were identified.
The integrated study was critical for optimizing recovery from this field. The optimum development plan recommends adding compressors and making re-completions to the upper sand and anticipates the recovery of 37 BCF more gas than previously predicted. Upper sand re-completions would drastically reduce water production and its handling costs as verified by a very recent re-completion job at an existing well.
Low-Liquid-Loading Multiphase Flow in Deepwater Production Risers: Effects of Insulation on Transient Processes After System Shut-In
Authors: Chin Y. Doreen 
Published: April 2020

Abstract
Gas/condensate flow with low liquid loading is a multiphase flow phenomenon commonly encountered in raw gas transportation. This paper discusses the effects of different insulation scenarios on the transient behaviors after shut-in of a deepwater pipeline/riser system that carries low-liquid-loading multiphase flow.
The investigated pipeline/riser system is located in the Gulf of Mexico at 5,000-ft water depth. The system consists of a 15-mile long subsea pipeline tieback and a 7,940-ft long steel catenary product export riser. The thermal insulation scenarios studied are: (1) the subsea pipeline is in a pipe-in-pipe configuration with insulation between the flowline and casing; the production riser is an 8-inch single pipe with external insulation coating; (2) both the subsea pipeline and production riser are in pipe-in-pipe configurations. For each scenario, two product flowrates with two gas-liquid ratios were investigated.
Numerical transient analyses were conducted by simulating the system shut-in conditions. The temperature and liquid holdup responses are presented. The effects of insulations on the responses are discussed based on fundamental heat transfer and multiphase flow principles. The results of this study will improve the understanding of transient behavior of low-liquid-loading multiphase flow after shut-in of insulated deepwater pipeline/riser systems, and provide beneficial information for deepwater field development.
Digital Image Analysis of the Rolls During Production of Aluminum Foils
Authors: Marchetti E. , Venlali F. 
Published: April 2020

Abstract
The morphological appearance of the cylinders and of the laminates have been assessed by digital image processing performed during a number of production campaign of aluminum foils. The statistical analysis performed on the cylinders have shown that it is possible to evidence the modifications induced by the rolling operation. Such modifications have been found both in axial direction of the cylinders and in the longitudinal direction of the laminates. Yet, roughness measurements performed on the cylinders did not show any variation along the axial direction.
Solutions of Higher Class and Their Computations for Polymer Flows: Oldroyd-B Constitutive Model
Authors: Surana K. S. , Nayak H. Vijayendra 
Published: April 2020

Abstract
This paper presents formulations, computations and investigations of the solutions of class C00 and C11 for two dimensional viscoelastic fluid flows in u, v, p, τijp, τijs with Oldroyd-B constitutive model using p-version Least Squares Finite Element Formulation (LSFEF). The main thrust of the research work presented in the paper is to employ ‘right class of interpolations’ and the best computational strategy to establish: i) when does Oldroyd-B model begins to fail in simulating the correct physics of flow ii) when and why does the proposed computational process fail iii) is there a correlation between i) and ii). Fully developed flow between parallel plates and the stick-slip problems are used as model problems.
The investigations presented in this paper reveal the following. a) The manner in which the stresses are non-dimensionalized significantly influences the performance of the iterative procedure of solving nonlinear algebraic equations. b) Solutions of the class C00 are always the wrong class of solutions of GDEs in variables u, v, p, τijp and τijs and thus spurious. c) C11 class of solutions are the right class of solutions of the GDEs in variables u, v, p, τijp and τijs. d) In the flow domains, containing sharp gradients of the dependent variables, conservation of mass is difficult to achieve at lower p-levels (worse for coarse meshes). e) An augmented form of GDEs are proposed that always ensure conservation of mass at all p-levels regardless of the mesh and the nature of the solution gradients. f) We demonstrate that Oldroyd-B model describes correct physics of dilute polymer solutions of constant viscosity only for a limited range of Deborah numbers. Beyond this range, the computed solutions are not in agreement with the flow physics (thus spurious) even though the proposed computational process works exceptionally well. g) Numerical studies with graded meshes and high p-levels presented in this paper are aimed towards establishing and demonstrating detail behavior of local as well as global nature of the computed 10 solutions, h) Various norms are proposed and tested to judge local and global dominance of elasticity or viscous behavior 1) New definitions are proposed for elongational (extensional) viscosity. The proposed definitions are more in conformity and agreement with the flow physics compared to currently used definitions j) A significant aspect and strength of our work is that we utilize straightforward p-version LSFEF with C00 and C11 type interpolations without linearizing GDEs and that SUPG, SUPG/DC, SUPG/DC/LS operators are neither needed nor used.
Forced Vibrations of a Transversely Isotropic Composite Containing an External Circular Crack
Authors: Tsai Y. M. 
Published: April 2020

Abstract
The problem of a transversely isotropic composite containing an external circular crack is investigated using the method of Hankel transforms. A pair of tensile vibratory forces of equal amplitude are applied normal to the crack surface at infinity. A complete contour integration is employed to simplify the expressions of the results.
An exact expression of the dynamic stress-intensity factor is obtained as a function of the force frequency and the anisotropic material constants. The normalized dynamic stress-intensity factor is shown to have different maximum values at different force frequencies for the sample fiber-reinforced and metal matrix composites.
The deviation of the dynamic crack surface displacement from the associated static displacement is also shown to be dependent on the force frequency and the anisotropy of the material.
Experimental Research of Railway Turnouts Vibrations
Authors: Szafranski Wieslaw 
Published: April 2020

Abstract
A method and a measuring range of displacements and accelerations, vertical and transversal of moving parts of railway turnouts are presented in this paper. Vertical vibrations have destructive influence for railway-track construction. Transversal vibrations are in exact relation with safety of railway traffic. These vibrations are getting up from excitations of moving track vehicles.
The measurements have been made in special moving turnout points. Two presently used turnouts having the same turning radius were investigated. One of them is new generation turnout, but the second one has classical construction.
In finally conclusion is drawing the relation between velocity of excitation and the values of vibration parameters. Moreover explain why to use more complicated construction in turnouts of new generation.