bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallization histories of the group IIF iron meteorites and Eagle Station pallasites
Authors: Hilton Connor D. , Ash Richard D. , Walker Richard J. 
Published: December 2020

AbstractThe group IIF iron meteorites and Eagle Station pallasites (PES) have highly siderophile element abundances (HSE; Re, Os, Ir, Ru, Pt, and Pd) of metal that are consistent with formation in planetesimal cores by fractional crystallization with minor to major solid metal–liquid metal mixing. Modeling of HSE abundances of the IIF irons indicates a complex formation history that included the mixing of primitive and evolved solid and liquid metals. By contrast, modeling of HSE abundances of PES metal suggests these meteorites formed mainly as equilibrium solids from a common liquid. Abundances of some of the siderophile elements in the IIF irons and PES are permissive of a common core origin; however, the abundances of W and Ni indicate the PES ultimately formed on a more oxidized body. The PES most likely formed by the injection of olivine present at the core–mantle boundary into a metallic core liquid as a result of impact. The core then crystallized inward, trapping the olivine.
Nationalism and self‐determination in contemporary Ethiopia
Authors: Berhe Mulugeta Gebrehiwot , Gebresilassie Feseha Habtetsion 
Published: December 2020

AbstractThe 1995 Ethiopian Constitution envisions a multinational state with the right to self‐determination, including secession, given to the nations, nationalities, and peoples of the country. This remarkable document is a product of a unique combination of Ethiopia's history, Marxist‐Leninist debates of the 1974 revolution, and political circumstances of the time the Ethiopian People's Revolutionary Democratic Front (EPRDF) took power in 1991. The subsequent 20 years witnessed a concerted attempt to implement measures for federal decentralization alongside continued political centralization in the ruling party, with several intended and unintended consequences. Since 2016, a combination of the manipulation of constitutional provisions for personal and factional advantage, and polarized perspectives over the identity and future of the country, have unveiled a chapter of political crisis. The 1995 Constitution is hardly a cause of this crisis, yet the fate of the Constitution has become central to the dynamics of the crisis.
The effect of narrow‐band ultraviolet B radiation on sleep, happiness, and appetite: A prospective cohort study
Authors: Vashurin Ilan , Barzilai Aviv , Baum Sharon , Ohana Orly , Pavlotsky Felix , Greenberger Shoshana 
Published: December 2020

AbstractBackgroundThe health benefits of sunlight are well documented, including the effects on happiness and sleep. However, only a few studies have investigated the benefits of artificial narrow‐band ultraviolet B (NB‐UVB) radiation.ObjectivesTo investigate the effect of NB‐UVB on sleep quality, happiness, and appetite.MethodsPatients from a single phototherapy unit were selected, and their epidemiological characteristics were documented. Subjects were asked to complete questionnaires including the Pittsburg Sleep Quality Index (PSQI), Subjective Happiness Scale (SHS), and the Simplified Nutritional Appetite Questionnaire (SNAQ) 4 weeks before and after the initiation of the NB‐UVB therapy. The sample consisted of 52 patients.ResultsFour weeks after the initiation of NB‐UVB sessions, sleep quality was significantly improved (the PSQI decreased from 6.5 to 5.23 (t = −3.52, P < .01). In contrast, subjective happiness did not improve (the SHS decreased from baseline 5.5 to 5.2, P > .05). Similarly, appetite did not change (the SNAQ score increased from baseline 14.75 to 15.05, P > .05) and body mass index was not affected by phototherapy. In general, men were found to have better sleep quality before and after UV light therapy.ConclusionOur data suggest that NB‐UVB exposure over 4 weeks improves sleep quality; however, it does not influence happiness or appetite.
Evaluation of Quantiferon®‐Monitor as a biomarker of immunosuppression and predictor of infection in lung transplant recipients
Authors: Gardiner Bradley J. , Lee Sue J. , Cristiano Yvonne , Levvey Bronwyn J. , Sullivan Lucy C. , Snell Gregory I. , Peleg Anton Y. , Westall Glen P. 
Published: December 2020

AbstractBackgroundOptimizing immunosuppression in lung transplant recipients (LTR) is crucially important in minimizing the risk of infection and rejection. Quantiferon®‐Monitor (QFM) is a candidate immune function biomarker which has not yet been rigorously evaluated in the lung transplant setting. The aim of this prospective cohort study was to explore relationships between QFM results, immunosuppression, and infection/rejection in LTR.MethodsQFM, which measures interferon‐γ after stimulation with innate and adaptive immune antigens, was tested before and at 2, 6, 12, 24 and 52 weeks post‐transplant. Immunosuppression relationships were assessed with linear mixed effects models. Clinical outcomes were analyzed based on the preceding QFM result.ResultsEighty LTR were included. Median pre‐transplant QFM levels were 171 IU/mL (IQR 45‐461), decreasing to 3 IU/mL (IQR 1‐8) at 2 weeks post‐transplant then progressively recovering toward baseline with time from transplant. Prednisolone was strongly inversely associated with QFM level (0.1 mg/kg dose increase correlating with 88 IU/mL QFM decrease, 95% CI 61‐114,P < .001). Patients with QFM values <10 and <60 IU/mL were more likely to develop a serious opportunistic infection between 3 and 6 months (HR 6.38, 95% CI 1.37‐29.66,P = .02) and 6‐12 months (HR 3.25, 95% CI 1.11‐9.49,P = .03) post‐transplant, respectively.ConclusionsQFM values declined significantly post‐transplant, with patients recovering at different rates. Prednisolone dose significantly impacted QFM results. Low levels were associated with infection beyond 3 months post‐transplant, suggesting that QFM may be able to identify overly immunosuppressed patients who could be targeted for dose reduction. Larger prospective studies are needed to further evaluate this promising assay.
Haptic Display of Interaction Forces in MEMS Assembly Processes
Authors: Evans Daniel J. , Jayaram Sankar , Feddema John T. , Jayaram Uma , Johnson William A. , Seywald Hans 
Published: December 2020

Abstract
In recent years, the world economy has seen expansive market growth in the area of Micro-Electro Mechanical Systems (MEMS). It is predicted that the MEMS market could reach more than $34 billion by the year 2002. Today, commercially available MEMS products include accelerometers for airbags and inkjet printer heads. These products require little or no assembly because a monolithic integrated circuit process is used to develop the devices. However, future MEMS will be more elaborate. Monolithic integration is not feasible when incompatible processes, complex geometry, or different materials are involved. For these cases, new and extremely precise micro-manipulation capabilities will be required for successful product realization. This paper outlines the design and implementation of a computer aided simulation of Micro Electro Mechanical Systems (MEMS) assembly utilizing force feedback devices for display of forces of interaction. The system described in this paper solves boundary element equations for electrostatic forces between MEMS components and then displays this solution in near real time with the help of the PHANToM force feedback device. Issues discussed in this paper include: boundary element solutions of electrostatic forces, interpolation of a six degree of freedom solution grid, scaling up of electrostatic forces to human scale, and use of the PHANToM device for haptic display of electrostatic and contact forces.
Predicting Product Cosmetic Quality Using Virtual Environments
Authors: Maxfield John , Juster Neal P. , Dew Peter M. , Taylor Stephen , Fitchie Martin , Ion William J. , Zhao Jeff , Thompson Martin 
Published: December 2020

Abstract
This paper describes a previously unreported application of virtual environments — the prediction of product cosmetic quality. Successful prediction of cosmetic quality without the production of a physical prototype requires the integration of a number of ‘software’ models. The models include an assembly model representing the manner in which the product is put together; an environment model providing a real world graphical context for the product; a behaviour model representing how the product moves and deforms under use conditions; a tolerance model representing the allowable variation in the product due to manufacturing and assembly variation; and an interaction model enabling the user to interact with the system. This paper presents interim results of a research project that has combined these models and implemented them within an automotive design and manufacturing process during the development of a new automobile. The paper contains the results of initial user evaluation and issues for future research.
Using the Palm Computer to Augment the Design of Machine Elements
Authors: Shoup Terry E. 
Published: December 2020

Abstract
This paper discusses the utility of the palm sized computers for augmenting the design of machine elements. Two palm computer programs are presented for handling frequently occurring problems in stress analysis in order to demonstrate the utility of the palm computer in this environment. One of these programs handles the manipulation of a three dimensional state of stress and the other program handles stress concentration factors. These modules facilitate computational processes that would not be possible with a traditional hand-held calculator. These programs are useful for students of machine design and practitioners as well.
Dichromatic Graphs: A Tool for the Algorithmic Education of Mechanical Engineers
Authors: Escanaverino Jose Martinez , Toll Alejandra Garcia , Cardenas Tania Ortiz 
Published: December 2020

Abstract
Computational problems, that is, those whose solution is given by numerical quantities, are a central theme in every field of science and technology. The present paper shows that the learning of mechanical engineering subjects where posing and solution of computational problems is important can be simplified if the structures of mathematical models, computational problems and algorithms are represented by means of dichromatic graphs. Playing the role of unusual route maps, these graphs allow the student to understand at a glance what a computational problem is, and the flow of information in the algorithms that solve the same problem. Even more important, these graphs are both guide and record of the algorithm synthesis process. The results of practical classroom experiences at graduate and undergraduate levels are given. Theoretical concepts on the paper are illustrated by means of an example taken from real-life mechanical engineering education.
Software Tools for Abstract Prototyping of Design Support Tools
Authors: Opiyo Eliab Z. , Horváth Imre , Vergeest Joris S. M. 
Published: December 2020

Abstract
Systematic design, user centered implementation and testing to requirements can contribute significantly to assuring quality of design support tools. The problem is that disorganized requirements elicitation and testing is generally time consuming and can sometimes lead to formulation of incomplete specification requirements. Furthermore, current software testing techniques involve usage of partially or fully implemented prototypes and thus provide feedback for the developers too late. These problems can be avoided through the application of a novel computer based pre-implementation testing technique, called abstract prototyping. It comprises structured multistage design and evaluation cycles, involving both the developers and the potential end-users as the evaluation subjects. This technique introduces quality improvement cycles early in the development process, well before the implementation of prototypes, and provides a structured framework for defining requirements and testing of design support tools.
In this paper we first introduce the abstract prototyping technique. Then we describe the architecture and functionality of the software developed for abstract prototyping. We also give an example on the application of this software tool for evaluation of the particle system theory for vague modeling of shapes in conceptual design. This software tool facilitated definition of requirements and testing to the formulated requirements. In this case the particle system theory represented the highest level of abstraction of the vague modeling software tool. The same procedure can be used in the subsequent levels of abstraction of methods, algorithms and pilot implementations. We can argue that the abstract prototyping technique helps to achieve the kinds of improvement and quality gains that are expected in the development of new design support tools and in upgrading the existing tools.
Sliced Geometry Representation Based on Implicit Curves
Authors: Park Seok-Min , Crawford Richard H. , Beaman Joseph J. 
Published: December 2020

Abstract
Current solid freeform fabrication data exchange practice supports only discretized approximations of part geometry. For producing accurate patterns and functional parts, the adequacy of linear approximations is suspect. The most efficient way of minimizing the degradation of geometric entities is to eliminate this intermediate format and directly exchange the source geometry. However, each commercial CAD vendor has its own representation, and choosing a single format has proven somewhat problematic. As an alternative, we have developed a method to approximate a contour from a set of discrete points using high order polynomials and to efficiently generate scan vectors from the high order contour. Our method exploits the so-called algebraic spline (A-spline) curve. Data fitting using A-splines gives a set of implicit curve segments with C3 local continuity, compared to the C0 continuous collection of line segments that is common in SFF practice. The A-spline approximation is capable of representing sliced geometry generated from various types of surfaces, including parametric, implicit, and mixed surface forms. The A-spline approximation method was tested by fabricating a curved object by Selective Laser Sintering. The resulting part showed higher surface quality with none of the tessellation artifacts inherent in part generation from polygonal contours. The run-time efficiency of the method is comparable to that of linear contour processing.
Integration of Commercial CAD With Commercial NC Programming Packages
Authors: Miao Huikang K. , Sridharan Nandakumar , Shah Jami J. 
Published: December 2020

Abstract
This paper focuses on the issues in automating the various tasks in process planning and on the issues in integrating the process-planning task with commercial CAD/CAM software. Automated process planning involves two important tasks; machining feature extraction and feature-based process planning. The integration of CAD and NC may be done by two alternative approaches: external or internal. This study uses the external approach. The CAD model of the part and the stock is exported to a format compatible with the external geometry engine. The machining feature recognition system communicates with the external geometry engine through APIs to obtain geometric and topological information required for feature recognition. The machining knowledge embedded in the recognized features is used by the process-planner to chalk out a process plan for the part. The machining features are classified into three broad categories each with machining significance specific to NC machining, so that when extracted they are useful in making process-planning decisions. Setup Planning, Operation Sequencing and Tool Selection is performed automatically based on criteria such as feature shapes, feature locations, tool access directions and feasibility of workpiece locating and clamping. The detailed process planning is based on a commercial CAD/CAM/CAE package, I-DEAS.
Features As an Abstraction for Designer Convenience in the Design of Complex Products
Authors: Summers Joshua D. , Maxwell Douglas , Camp Christopher , Butler Alley C. 
Published: December 2020

Abstract
This paper reports on a research effort involving design of a class of significantly complex products — nuclear submarines. It focuses on the use of features as a means of design abstraction, and it is found that a principal motivation for the use of features in this design environment is the convenience of the early stage submarine designer. To support this argument, a review of feature research is presented. Experiments in the development of feature catalogs are described, and implementation through two generations of feature based submarine CAD systems are discussed. The architecture of the feature based submarine CAD systems includes the use of Microsoft Foundation Classes (MFC), the ACIS geometric modeler, and user interfaces which store/recall hierarchical submarine feature information easily. Strong connections to object-oriented programming and object-oriented databases are recognized. Conclusions are drawn regarding the use of features for designer convenience and regarding support provided by hierarchical, parameterized features for other means of design automation.
Use of Rapid Prototyping Methods for Production
Authors: Markowski Andrzej , Petersen Harry 
Published: December 2020

Abstract
Rapid Prototyping and Rapid Tooling (RP/RT) can reduce time-to-market by creating physical parts and tooling from computer files. These can be used for verification of designs, tests and marketing, and also as final products or tools for short run production. Education is critical, because effective use of RP/RT technology requires preparation and training of all parties, including designers, engineers, manufacturing technologists, and business people. This paper reviews advances in RP/RT along with research, education, and a case study conducted at Minnesota State University, Mankato.
Turbulent Dispersed Particulate Flow in a Zigzag Channel
Authors: Akbar Muhammad K. , Sharif Muhammad A. R. , Bradt Richard C. 
Published: December 2020

Abstract
A Lagrangian simulation technique to predict the trajectories of solid particles in turbulent flow of a liquid continuous phase is presented. The method assumes one-way coupling, i.e., influence of particle on the flow is neglected. Mass loading ratio is as low as the order of 1 × 10−5. Drag, Magnus lift, Saffman lift across the flow direction, and gravitational forces are considered. Particle-particle and particle-wall interactions have been counted. On the other hand, turbulent fluctuation effects are neglected. Particle trajectories in a zigzag channel are computed. Effects of particle size, particle drop position, zigzag angle of the channel and inlet flow Reynolds number have been investigated. Particle size and/or density and initial particle placement position have been found to have significant effect on the trajectories.
Enhanced Methane-Air Mixing Using Shock and Expansion Waves
Authors: Brasoveanu Dan , Gupta Ashwani K. 
Published: December 2020

Abstract
A unified model of gaseous fuel-air mixing is applied here to study the effect of shock waves on enhanced methane-air mixing. The model uses the fuel mass fraction within infinitesimal fluid elements and the total derivative of this fraction with respect to time to measure the degree and rate of mixing, respectively. The model is strictly accurate only for low-pressure combustors because of the ideal gas law assumption incorporated in the model. The model is also limited to gaseous fuels that contain single chemical specie, or behave like single specie. The model can be applied to any operational conditions or combustor geometry. Results show that mixing can be completed within the narrow region of the shock wave and therefore in a negligibly short time, if pressure, temperature and velocity distributions within this region are optimized. Furthermore, combining the effects of air preheat and shock waves can enhance both mixing with air penetration into fuel and fuel dispersion into the surrounding air. These results provide important guidelines for the design of supersonic combustors to achieve high efficiency and high intensity, while maintaining a low level of pollutants emission.
Problems and Sample Calculations Related to Fire Development
Authors: Kim Hyeong-Jin , Lilley David G. 
Published: December 2020

Abstract
Release of toxic, flammable and/or explosive materials into the atmosphere is extremely dangerous. If an ignition source is found, the resulting fire can often be devastating. Information, analysis and calculations of fire dynamic phenomena can assist in understanding and applying scientific information to real-world fire situations. Fire dynamicists can develop an appreciation for technical/scientific understanding of the phenomena and its applicability to real-world practical down-to-earth situations. Some sample calculations are exhibited to illustrate several aspects of fire behavior.
On Turbulent Secondary Flows by Using Linear and Nonlinear k–ω Model
Authors: Song B. , Amano R. S. 
Published: December 2020

Abstract
In the present study, the fully developed turbulent secondary flows inside rotating and non-rotating square duct are numerically simulated using the linear and nonlinear k–ω models. For non-rotating duct, an eight-vortex structure is well captured by the nonlinear k–ω model. For rotating duct, it is interesting to notice that the two vortices are generated when Ro = 0.05, four vortices are presented when Ro = 0.15, and two vortices appeared when the rotational speed is increased up to Ro = 0.35. Although the linear and nonlinear models all produce reasonable results, the different results are also exhibited with these models. For example, the nonlinear model produces a stable effect in the pressure side and predicts less distortion region than the linear model. In the suction side, the linear k–ω model produces greater gradients than the linear model which seems to be realistic.
Design Rules for Selecting and Designing Compliant Mechanisms for Rigid-Body Replacement Synthesis
Authors: Berglund Michael D. , Magleby Spencer P. , Howell Larry L. 
Published: December 2020

Abstract
There exists a need for methodologies on designing mechanical devices with flexible elements (compliant mechanisms). Many engineers currently have little direction in their designing efforts and have difficulty improving the performance of devices with flexible members. This paper presents a step towards a process and a set of rules for designing compliant mechanisms which aid engineers in selecting the best design concept among a set of alternatives. The approach is a more rational method for selecting and improving designs than the existing intuitive approach engineers now take. The general design rules aid the engineer in identifying good and bad design features and practices for devices containing flexible elements. The design rules help engineers avoid oversights and/or overlooked factors in design problems. Since many equivalent compliant mechanisms can be made from a single rigid-body solution, the rules can help engineers select between the compliant alternative designs.