bluuebunny/crossref_metadata_2025 huggingface dataset:
Toward an integrative model of moral‐value perception
Authors: Young Robert L.
Published: March 2021

Moral‐value perception occurs when sensory perception is directed by cognitive schemas, which selectively sample information in objects and events that represent personally valued means or ends. As a result of the perception of such value representations people experience affect ranging from strongly negative to strongly positive. If one's schemas direct attention to elements of objects or actions that verify schematic expectations, and spark little of no noticeable affect, the new information automatically produces minor alterations of the schema. However, if attention is directed or drawn to information that produces strong affect, and is contradictory of activated schemas, one is likely to engage in conscious assessment, through which the information is re‐conceptualized in a way that preserves schematic integrity. Based on multidisciplinary analysis, this paper (1) addresses the ways in which the perception of things within the natural world are represented in moral‐value perceptions, (2) identifies important cognitive, affective and emotional processes involved in the ongoing experience of such perception, and (3) illustrates some of the ways in which moral‐value perceptions influence moral assessments and judgements.
Does TRIPS (Agreement on Trade‐Related Aspects of Intellectual Property Rights) prevent COVID‐19 vaccines as a global public good?
Authors: Haugen Hans Morten
Published: March 2021

The article analyses the global public goods approach to COVID‐19 technologies, embedded in 2020 affirmations by the World Health Assembly (WHA), the UN Human Rights Council and G20 on broad immunization against COVID‐19. After identifying the access to COVID‐19 tools (ACT) Accelerator members, the UN efforts are identified, focusing primarily on the UN human rights bodies, acknowledging how these and the WHA have mutually reinforced each others' efforts. The article finds that the global public goods terminology appeared in UN resolutions in 2020, while wording that included vaccines—on an equal footing as medicines—appeared in 2016, and recognition of generic medicines appeared in 2019. The so‐called Trilateral Cooperation on IP and public health between two UN specialized agencies and the World Trade Organization (WTO) has increased awareness of the flexibilities within WTO's TRIPS Agreement. These flexibilities are explained. With notable exceptions, like India, these flexibilities are not widely applied in domestic legislation. A different emphasis characterizes the millennium development goals era as compared to the sustainable development goals era, and this shift is explained by applying relevant theories. Among pro‐TRIPS developed countries there is an acknowledgment of obstacles created by the IP system, but their overall position has not changed.
Efficient chito‐oligosaccharide utilization requires two TonB‐dependent transporters and one hexosaminidase in Cellvibrio japonicus
Authors: Monge Estela C. , Gardner Jeffrey G.
Published: March 2021

Chitin utilization by microbes plays a significant role in biosphere carbon and nitrogen cycling, and studying the microbial approaches used to degrade chitin will facilitate our understanding of bacterial strategies to degrade a broad range of recalcitrant polysaccharides. The early stages of chitin depolymerization by the bacterium Cellvibrio japonicus have been characterized and are dependent on one chitin‐specific lytic polysaccharide monooxygenase and nonredundant glycoside hydrolases from the family GH18 to generate chito‐oligosaccharides for entry into metabolism. Here, we describe the mechanisms for the latter stages of chitin utilization by C. japonicus with an emphasis on the fate of chito‐oligosaccharides. Our systems biology approach combined transcriptomics and bacterial genetics using ecologically relevant substrates to determine the essential mechanisms for chito‐oligosaccharide transport and catabolism in C. japonicus. Using RNAseq analysis we found a coordinated expression of genes that encode polysaccharide‐degrading enzymes. Mutational analysis determined that the hex20B gene product, predicted to encode a hexosaminidase, was required for efficient utilization of chito‐oligosaccharides. Furthermore, two gene loci (CJA_0353 and CJA_1157), which encode putative TonB‐dependent transporters, were also essential for chito‐oligosaccharides utilization. This study further develops our model of C. japonicus chitin metabolism and may be predictive for other environmentally or industrially important bacteria.
Multihazards Scenario Generator: A Network‐Based Simulation of Natural Disasters
Authors: Dunant Alexandre , Bebbington Mark , Davies Tim , Horton Pascal
Published: March 2021

The impact of natural disasters has been increasing in recent years. Despite the developing international interest in multihazard events, few studies quantify the dynamic interactions that characterize these phenomena. It is argued that without considering the dynamic complexity of natural catastrophes, impact assessments will underestimate risk and misinform emergency management priorities. The ability to generate multihazard scenarios with impacts at a desired level is important for emergency planning and resilience assessment. This article demonstrates a framework for using graph theory and networks to generate and model the complex impacts of multihazard scenarios. First, the combination of maximal hazard footprints and exposed nodes (e.g., infrastructure) is used to create the hazard network. Iterative simulation of the network, defined by actual hazard magnitudes, is then used to provide the overall compounded impact from a sequence of hazards. Outputs of the method are used to study distributional ranges of multihazards impact. The 2016 Kaikōura earthquake is used as a calibrating event to demonstrate that the method can reproduce the same scale of impacts as a real event. The cascading hazards included numerous landslides, allowing us to show that the scenario set generated includes the actual impacts that occurred during the 2016 events.
Arabidopsis leaf hydraulic conductance is regulated by xylem sap pH, controlled, in turn, by a P‐type H+‐ATPase of vascular bundle sheath cells
Authors: Grunwald Yael , Wigoda Noa , Sade Nir , Yaaran Adi , Torne Tanmayee , Gosa Sanbon Chaka , Moran Nava , Moshelion Menachem
Published: March 2021

The leaf vascular bundle sheath cells (BSCs) that tightly envelop the leaf veins, are a selective and dynamic barrier to xylem sap water and solutes radially entering the mesophyll cells. Under normal conditions, xylem sap pH below 6 is presumably important for driving and regulating the transmembranal solute transport. Having discovered recently a differentially high expression of a BSC proton pump, AHA2, we now test the hypothesis that it regulates the xylem sap pH and leaf radial water fluxes. We monitored the xylem sap pH in the veins of detached leaves of wild‐type Arabidopsis, AHA mutants and aha2 mutants complemented with AHA2 gene solely in BSCs. We tested an AHA inhibitor (vanadate) and stimulator (fusicoccin), and different pH buffers. We monitored their impact on the xylem sap pH and the leaf hydraulic conductance (Kleaf), and the effect of pH on the water osmotic permeability (Pf) of isolated BSCs protoplasts. We found that AHA2 is necessary for xylem sap acidification, and in turn, for elevating Kleaf. Conversely, AHA2 knockdown, which alkalinized the xylem sap, or, buffering its pH to 7.5, reduced Kleaf, and elevating external pH to 7.5 decreased the BSCs Pf. All these showed a causative link between AHA2 activity in BSCs and leaf radial hydraulic water conductance.
Genetic determinants of seed protein plasticity in response to the environment in Medicago truncatula
Authors: Cartelier Kevin , Aimé Delphine , Ly Vu Joseph , Combes‐Soia Lucie , Labas Valérie , Prosperi Jean‐Marie , Buitink Julia , Gallardo Karine , Le Signor Christine
Published: March 2021

As the frequency of extreme environmental events is expected to increase with climate change, identifying candidate genes for stabilizing the protein composition of legume seeds or optimizing this in a given environment is increasingly important. To elucidate the genetic determinants of seed protein plasticity, major seed proteins from 200 ecotypes of Medicago truncatula grown in four contrasting environments were quantified after one‐dimensional electrophoresis. The plasticity index of these proteins was recorded for each genotype as the slope of Finlay and Wilkinson's regression and then used for genome‐wide association studies (GWASs), enabling the identification of candidate genes for determining this plasticity. This list was enriched in genes related to transcription, DNA repair and signal transduction, with many of them being stress responsive. Other over‐represented genes were related to sulfur and aspartate family pathways leading to the synthesis of the nutritionally essential amino acids methionine and lysine. By placing these genes in metabolic pathways, and using a M. truncatula mutant impaired in regenerating methionine from S‐methylmethionine, we discovered that methionine recycling pathways are major contributors to globulin composition establishment and plasticity. These data provide a unique resource of genes that can be targeted to mitigate negative impacts of environmental stresses on seed protein composition.
Bonding work: Spacing relations through pregnancy apps
Authors: Hamper Josie , Nash Catherine
Published: March 2021

Smartphone pregnancy apps, which enable their users to track a pregnancy week by week and offer advice to coincide with each stage, have transformed the spaces and times in which pregnancy information can be accessed. In this paper we draw on recent geographical work on the family, relatedness, and digitally mediated forms of intimacy, to explore how these apps figure in the embodied, emotional, and relational geographies of pregnancy. We present an analysis of visual material from pregnancy apps and interviews with women in the UK who have used them, to examine how these apps are marketed as a means to facilitate the “bonding work” of forming a close relationship with the future baby through visual images of foetal development, and related to this, how they mobilise ideas of biologically naturalised and socially normative maternal bonding. For users, however, existing and future relationships with prospective fathers and grandparents, as well as the expected baby, are practised in the spaces of everyday life through the strategic and selective sharing of pregnancy information. Our attention to the spatialities and practices of making intergenerational and parental relationships shows how users of apps respond to ideas of physical closeness in pregnancy and how this intersects with ideas of relational closeness and connection as both natural and achieved through bonding work. Women's engagements with pregnancy apps can therefore provide important insights both into the contemporary making of intimate relationships through digital technologies and geographies of parenting and pregnancy.
A trend of dropping anti‐SARS‐CoV‐2 plaque reduction neutralization test titers over time in Canadian convalescent plasma donors
Authors: Drews Steven J. , Devine Dana V. , McManus Janet , Mendoza Emelissa , Manguiat Kathy , Wood Heidi , Girardin Roxie , Dupuis Alan , McDonough Kathleen , Drebot Michael
Published: March 2021

Background

Convalescent plasma products are a potential passive immunotherapy for Coronavirus disease 2019 (COVID‐19) disease. Various approaches have been utilized to determine the concentration of Severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2)‐neutralizing antibodies in plasma products. The Canadian Blood Services used Plaque Reduction Neutralization Test 50 (PRNT50)‐generated values to qualify convalescent plasma donations supporting clinical trials in Canada. This manuscript describes changes in PRNT50 titers of repeat male plasma donations collected approximately 1–4 months after onset of COVID‐19 signs and symptoms in donors.

Study Design and Methods

Men were eligible to donate if they: met standard criteria, were < 67 years of age, reported a previous SARS‐CoV‐2‐positive nucleic acid test, and recovered and were symptom free for at least 28 days prior to donation. Repeat donation analysis required at least one original and one repeat donation where a PRNT50 was performed.

Results

From April 29, 2020 to July 25, 2020, 156 donors donated once, with 78 (50%) of the donated plasma having PRNT50 titers of ≥1:160. Thirty‐seven (23.7%) of the donated plasma had a titer of 1:40 or 1:80 (individuals donating this plasma were asked to donate a second time only). A total of 30 donors (19.2%) had repeat donations. Of the repeat donors, 15 (50%) had at least an eightfold change from peak to trough PRNT50 titers within greater than 90 days after onset of COVID‐19 symptoms.

Conclusions

Blood operators cannot infer that SARS‐CoV‐2 PRNT50 will remain high in repeat plasma donors 3–4 months after onset of COVID‐19 symptoms.
Impact of pathogen reduction methods on immunological properties of the COVID‐19 convalescent plasma
Authors: Kostin Alexander I. , Lundgren Maria N. , Bulanov Andrey Y. , Ladygina Elena A. , Chirkova Karina S. , Gintsburg Alexander L. , Logunov Denis Y. , Dolzhikova Inna V. , Shcheblyakov Dmitry V. , Borovkova Natalia V. , Godkov Mikhail A. , Bazhenov Alexey I. , Shustov Valeriy V. , Bogdanova Alina S. , Kamalova Alina R. , Ganchin Vladimir V. , Dombrovskiy Eugene A. , Volkov Stanislav E. , Drozdova Nataliya E. , Petrikov Sergey S.
Published: March 2021

Background and objectives

COVID‐19 convalescent plasma is an experimental treatment against SARS‐CoV‐2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS‐CoV2 in convalescent plasma.

Materials and methods

A total of 140 plasma doses collected by plasmapheresis from COVID‐19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS‐CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S‐ and N‐proteins of SARS‐CoV‐2 were measured before and after pathogen reduction.

Results

The methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7%, respectively) had a one‐step (two‐step, respectively) decrease. Paired two‐sample comparisons (M vs. A, M vs. R and A vs. R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment.

Conclusion

Pathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID‐19 convalescent plasma compared to riboflavin.
Defining and Recognizing Cavity and Protrusion by Volumes
Authors: Sakurai Hiroshi , Chin Chia-Wei
Published: March 2021

In design and manufacturing, cavity features, such as holes and pockets, and protrusion features, such as bosses and ribs are commonly used. In this work, cavity and protrusion in a solid object were defined with the volumes enclosed by the faces of the object and their extensions. These definitions of cavity and protrusion match our intuitive notions of cavity and protrusion better than the commonly used definitions that consider the convexity and concavity of edges. Together with an algorithm called “spatial decomposition and composition”, the definitions provide a method to find cavities and protrusions in solid models. By applying graph matching commonly used in feature recognition to the volumes of cavity and protrusion, all the features in a solid model can be recognized whether they intersect or not.
Fluid Flow Modelling of an Automotive Engine Lubrication System
Authors: Fenton Marcus B. M. , Veshagh Ali
Published: March 2021

A computer model has been developed to provide a design analysis tool for assessing the flow characteristics of an engine lubrication system. Parametric studies can be conducted to predict the pressure and flow of oil throughout the lubrication system and to study the effects of various design parameters and operating conditions. This paper reports on the development of the engine lubrication system flow model at the Advanced Technology Centre in collaboration with Jaguar Cars. The results of the simulation model are assessed and its future potential as a computer aided analysis tool for engine development programmes is examined.
Emissions Control From IC Engines Using Advanced Combustion Chamber Design
Authors: Lu Jiang , Gupta Ashwani K. , Keating Eugene L. , Pouring Andrew A.
Published: March 2021

Numerical simulation of flow, combustion phenomena and pollutants emission characteristics have been obtained on an homogeneous-charged internal combustion engine having conventional flat piston and five other bowl-in-piston geometries. The code employed here uses the time marching procedure and solves the governing partial differential equations of multi-component chemically reactive flow by finite difference method. The transient solution is marched out in a sequence of time steps. The results show that the piston geometry affects the local flame properties which subsequently influences the pollutants emission level. The numerical results provide a cost effective means of developing advanced internal combustion engine chamber geometry design that provides high efficiency and low pollution. It is expected that increased computational tools will be used in the future for enhancing our understanding of the detailed combustion process in internal combustion engines and all other energy conversion systems. Such detailed information is critical for the development of advanced methods for energy conservation and environmental pollution control.
Numerical Simulation of the Flow in a Large Blast Simulator (LBS) Model
Authors: Opalka Klaus-Otto
Published: March 2021

This paper presents an assessment of the suitability of the USA-RG2 (Unified Solution Algorithm for Real Gas in Two Dimensions) computational fluid dynamics code for simulating the flow in a variable-area shock tunnel. A multi-zone gridding technique is used to model the 1:57-Scale Large Blast Simulator test facility at the U.S. Army Research Laboratory. Computations for various grid configurations employing inviscid and viscous solution algorithms with and without turbulence were executed, and the results are compared to experimental data. The need for an adequate mesh density in the grid to obtain a realistic flow simulation and the advantage of solving the full Navier-Stokes equations invoking a two-equation (k-ε) turbulence model are demonstrated for the experiment chosen as a bench mark in the assessment.
Computer Aided Analysis of High-Speed Single Row, Spherical Roller Bearings and Comparison With Full-Scale Test Results
Authors: Aggarwal A. K. , Michaels D. M. , Keller C. H.
Published: March 2021

Single row, angular contact, spherical roller bearings were designed, analyzed, and tested to study their feasibility in a high speed (1.15 million DN) spiral bevel input pinion application. A mathematical formulation, modeling the mechanics of internal motions, load and stress distributions, lubricant flow, sliding friction, heat generation and heat transfer, was developed to analyze the bearing performance and predict operating characteristics. An interactive computer program, capable of running on a DOS PC, was then developed to solve the bearing model for the given parameters of geometry, materials, loads, and speed. The computer program, named SASHBEAN (Sikorsky Aircraft Spherical Roller High Speed Bearing ANalysis), also provided the capability of “lumped capacity” thermal analyses of the bearing and its supporting mechanical system. Six test bearings, conforming to a 216 cylindrical roller bearing OD (140 mm) and ID (80mm), were manufactured using Carpenter Pyrowear® Alloy 53 steel rings. Both conventional (with steel rollers) and hybrid (with silicon nitride rollers) configurations were built and tested under different setup conditions of loads (radial and axial), speed, and lubrication. Excellent correlation was found between the full scale test data and the computer analyses results. The analysis also provides an excellent comparison of the performance characteristics of an hybrid bearing with those of an “all steel” bearing for this high speed transmission application.
The Study of a Multi-Component System Using a Complete CAD Software Package
Authors: Lewis Burton
Published: March 2021

When performing a complete study on the design of a multi-component system of at least two components, can a CAD software perform to expectations, that is, can we do a complete study on the entire multi-component system including bearing analysis for the contact between rotating components, and simple interference checks? In this paper, I will describe simple steps and precautions to take when doing a study on the design and performance of a multi-component system using a complete CAD package — including a Drafting module, a Solid Modeler, and a Finite Element Analysis module. I will use an example of a system of multiple rotating arms to show that from a 2-D blueprint, using the drafting module, we can enter the complete geometry of each arm separately, then pass on to the solid modeler. Once the solid 3-D model is constructed, we can transfer the model onto the finite element analysis module of the CAD package and test the model. After the model satisfies all requirements, we can come back to the solid modeler and check the “modified” version of the model by updating the previous solid model. If all is well at this point, then we can move on to the superposition of the 3-D solid model into a 2-D version to perform tolerance analysis. After tolerance analysis, we can move on to the final stage which is to update the 2-D drafting version adding the tolerances recently obtained.

This is a general outline and should be straight forward except for the problems that we could encounter especially in the solid modeler and the finite element analysis module. The study or design principals of a multi-component system is not the subject of this paper, but how to perform such a study using all the available modules of a CAD package. There are few complete CAD packages on the market today that allow such a study, but transferring data, whether it is of finite elements, solid models, or 2-D geometry, is much easier today using a variety of different types of transfer files. Sometimes, data is lost so when writing a data file, it is always best to check the file afterwards. This guaranties a successful writing of the data file.
Vibration and Control of the Flexible Manipulator
Authors: Yeh Chuntien
Published: March 2021

Because of the structural flexibility of the flexible manipulator, the exercise of effective control is a challenging problem. Thus, the development of an effective control system must encompass consideration of the manipulator elasticities. This paper proposes a two-stage control algorithm, including (1) computer-aided trajectory scheduling to drive a hypothetical rigid-body manipulator “close” to the standards of actual flexible manipulators, and (2) a linear-state feedback controller based upon the hypothetical model. The proposed algorithm is implemented for a two-link, rigid/flexible manipulator. Based upon simplified computational requirements, comparison of the proposed procedure to those previously considered indicates that it is capable of providing effective means of control.
Impinging Flame Prediction for CVD Diamond Synthesis
Authors: Dong Mingchun , Lilley David G.
Published: March 2021

High-temperature flames impinging normally onto adiabatic surfaces are considered. These are important in the CVD (chemical vapor deposition) diamond synthesis method for diamond growth on surfaces. Problems of complex chemistry and the mechanism of diamond growth are discussed. The present paper has illustrated the effects of several key parameters on the substrate surface temperature and flowfield for CVD diamond synthesis by impinging oxy-acetylene jet flames. The studies were concerned with combustion flowfield predictions, oxy-acetylene flames, axisymmetric-vertical impingement on an adiabatic surface, and the effects of varying the nozzle-substrate separation distance, nozzle size, overall equivalence ratio and flow rate on the substrate surface temperature and flowfield. This investigation provides a key to linking the flame with diamond growth rate on the substrate surface, complements the other facets of the project, and shows that the parametric influences can be predicted with relative ease, thereby extending the range of previously found experimental data.
Computer Assisted Design of Rubber Shear Springs
Authors: Shoup T. E. , Fegan G. R.
Published: March 2021

While analysis procedures for the design of rubber mountings have existed for a number of years, the nonlinearity of these useful devices has limited the number of robust design procedures that are available. This paper presents a design procedure for the static deflections of rubber shear springs that accommodates the nonlinear behavior of these devices. It is believed that this is the first time such numerical procedures have been described in the design literature. The procedures are made possible by a combination of numerical approximations of nonlinear data in the engineering literature and numerical methods for handling transcendental relationships. Such design procedures would clearly not be possible without the use of digital computers and numerical optimization techniques. Design examples are presented to illustrate the use of the numerical procedure.
A Case Study of APC Based Performance Monitoring System Designed for Unit 2 at Danskammer Electric Generating Plant
Authors: Benson Eric G. , Solinsky Tom F.
Published: March 2021

This paper describes the system architecture, requirements and results of a Personal Computer (PC) based distributed control system utilized for monitoring the performance of a heat pipe air heater. The Performance Monitoring System was developed by Proto-Power Corporation for use at Central Hudson Gas & Electric Corporation’s Danskammer Unit 2 Electric Generating Station.
CAFP: Computer-Aided Fixture Planning
Authors: Fuh Jerry Y. , Chang Chao-Hwa , Melkanoff Michel A. , Rau Hsin
Published: March 2021

Fixture planning is an indispensable part of a manufacturing process planning routine. This paper introduces a rational approach to computer-aided fixture planning (CAFP). A method of fixture classification and selection is introduced for planning of modular fixtures. The location of each fixture component is determined according to the common fixturing principles. We has developed a prototype CAFP system and linked to a commercial CAD system, namely CADAM. Modular fixture elements are automatically selected by the system, and the generated fixture layout can be displayed on-screen after assembly. For verification and optimization of a fixturing scheme, a fixture analysis module is also developed. An iteration method is used to solve the fixturing constraint equations and to determine the adequate clamping forces for holding the workpiece during machining processes.
Leaf Pruning and Node Consolidation: Two Methods of Reducing Distribution Network Model Size Without Sacrificing Simulation Accuracy
Authors: Miller John L. , Hayes Caroline
Published: March 2021

Large distribution networks often need to be modified to meet new demands. Designers use CAD and load-flow simulators to determine the characteristics of gas, liquid, and electric power distribution networks. Running the simulations required to engineer changes to a network is a lengthy process. The number of alternatives which can be explored depends upon the number of simulations which can be fit into the time allotted for design. Removing unimportant detail from a complete network representation results in a shorter per-simulation run time. Leaf pruning and node consolidation are two methods used to remove such details. These methods rely on the characteristics of the graph representation of the network, and so should apply to all steady-state load-flow simulations. Using leaf pruning and node consolidation together, per-simulation time can be cut tenfold, usually without significantly affecting total simulation accuracy. A reduction in per-simulation time translates into a less costly network analysis of the same quality as previously possible, or a more thorough analysis of network characteristics in the time period set aside for design. Steam distribution networks are used to illustrate the methods discussed.
3D-to-2D Mapping of Cutter Paths in NC Programming of Complex Engineering Parts
Authors: Chang Chao-Hwa
Published: March 2021

The concept of mapping a three dimensional (3D) contouring cutter path with major motion in a plane parallel to the Z axis onto the X-Y plane or one perpendicular to the Z axis is introduced. A systematic method is developed that can be used to program, in APT or other high-level languages, complex contouring cutter motion based on the concept introduced. As a result, NC programming of contouring motion for many complex engineering parts on a 3-axis numerically controlled (NC) milling machine, which is often considered difficult, can be greatly simplified. Part examples are discussed; and the APT programs defining the cutter path based on the 3D-to-2D mapping concept, are also analyzed in detail. The concept and method introduced proved to be a powerful tool for programming the NC machining process for many parts, particularly dies and molds.
Effect of Inlet Flow Parameters on Confined Turbulent Swirling Flow
Authors: Dong Mingchun , Lilley David G.
Published: March 2021

The development of a primitive-variable finite difference computer code is discussed, with application to a turbulent swirling nonreacting flow in a typical combustor. Primary air enters through the main inlet, and a secondary annular inlet in the outer wall is permitted through which secondary air flows. Parameters of special interest include the secondary to primary velocity ratio, primary swirl and contraction angles, and secondary swirl and upstream angles. Combustor flowfield predictions are given to illustrate the effects of these parameters on the flowfield (velocities and turbulence levels), and the dramatic effects are illustrated via velocity profiles and streamline patterns.
New Algorithm for Solution of the Non-Linear Equation Systems Occurring in the Design of Thermal Systems
Authors: Saraç Halil Ibrahim , Güven Hasan Riza , Sözbir Nedim , Uysal Ünal
Published: March 2021

Models used for the design of thermal systems often lead to non-linear equations which can be converted to linear systems. In this paper, a new algorithm is described for the solution of linear equation systems which have normal or ill-conditioned form A new algorithm and the Gauss-Seidel method were used for two-stage air compression with an inter-cooler. The solutions obtained by using two different methods are compared.
Implementation of the Hartley-Transform-Based Block LMS Algorithm
Authors: Ogunfunmi Tokunbo
Published: March 2021

This paper presents a cost-effective The Frequency-domain Least-Mean-Square (FLMS) adaptive algorithm (or more generally the Transform-domain LMS adaptive algorithm) [12], [13] has mainly two advantages over the conventional LMS algorithm [19]. The first is that it overcomes the slow convergence of the LMS algorithm by orthogonalizing the input (thereby performing better than the LMS for correlated input signals) and the second advantage is that it can be used for implementing the time-domain Block LMS (BLMS) algorithms as well [18].

The Hartley transform is a newly introduced real-to-real transform that is a suitable replacement for the complex Fourier transform [1] and [2] in several adaptive filtering applications such as adaptive interference cancellation that has wide applicability to problems in telecommunications, biomedical engineering, etc.

The realization of the Transform-domain BLMS adaptive algorithm based on the Discrete Hartley Transforms (DHT) and its implementation on the TMS320C30 digital signal processor chip is described.
A Representation Language for Mechanical Behavior
Authors: Neville Dorothy , Joskowicz Leo
Published: March 2021

Automating mechanism design requires developing a representation language for describing mechanism behavior. The language is necessary to specify design requirements, to describe existing mechanisms, and to catalog them for design reuse. This paper presents a simple and expressive language for describing the behavior of fixed-axes mechanisms. The language uses predicates and algebraic relations to describe the positions and motions of each part of the mechanism and the relationships between them. It allows both accurate and complete descriptions and partial, abstract, and under-specified descriptions. We show that the language is computationally viable by describing how to automatically derive behavioral descriptions stated in the language from the mechanism structure. To test its usefulness, we describe a design validation algorithm that determines if a given mechanism structure can produce desired behaviors stated in the language.
Development of a Machine Understandable Language for Design Process Representation
Authors: Shah Jami J. , Bliznakov Plamen I. , Urban Susan D.
Published: March 2021

This paper describes the work in progress at Arizona State University to develop a design process description language. The intent is to go beyond decision making level in recording design activities, thus providing a basis for broad application of the proposed representation. At the same time the granularity is limited to a feasible level. The design language proposed in this paper currently is Prolog-based. It is able to relate the sequence of actions to attributes of the design artifacts, thus, providing reference to the product data. Specifics of the design process which are reflected in a natural way include iterations of the activities, versioning of the designs, as well as reasons, purpose, constraints, and method / knowledge / technique used for design decisions (although the latter is currently done in a somewhat unstructured manner). The association between rationale, actions, and artifacts is captured, so explanation of previous designs is adequately supported.
The Synthesis of Planar Linkages to Satisfy an Approximate Motion Specification
Authors: Mirth John A.
Published: March 2021

This paper introduces the method of quasi-precision position synthesis for planar linkages. A quasi-precision position is defined by an approximate region that the mechanism must pass through. The quasi-precision position problem specification generates an increased design region by not requiring the accurate position specification that is characteristic of optimization and precision position methods. The design space is generated by intersecting the individual design regions of different four position sets. Each four position set consists of three exact positions plus one quasi-precision position. The method allows for the use of any number of quasi-precision positions. The result of using quasi-precision positions is an increase in the available design space without violating the basic problem constraints. The increased solution region gives the designer a greater variety of choices while reducing the number of required design iterations. The complete process of quasi-precision position synthesis is presented through the use of an example.
Testing of a Relative Comparison Method for Evaluating Design Concept Alternatives
Authors: Diteman Michele L. , Stauffer Larry A.
Published: March 2021

Two methods for assessing conceptual alternatives for the solution of a design problem are compared in the areas of reliability, sensitivity, and validity. The method utilizing relative comparisons has been shown in previous analysis to be more usable than the method utilizing absolute ratings, but the current analysis shows that the relative comparison method does not produce results as well as the absolute rating method in the areas of reliability and validity.
An Exploration of Engineering Learning
Authors: Brereton Margot F. , Leifer Larry J. , Greeno James , Lewis Jason , Linde Charlotte
Published: March 2021

This paper explores how students learn engineering, paying particular attention to development of engineering intuition.

Examination of traditional engineering curricula reveals that design and analysis are taught in separate classes. In contrast, learning theory and engineering design practice suggest engineering is best learned through integrated experiences. “Synalysis exercises”, which integrate activities in problem formulation, analysis and synthesis, have been developed to study integrated learning. Video analysis of the exercises reveals how students use formal knowledge in practice, the processes by which they learn and the social context in which learning occurs. The integration of dissimilar activities in synalysis exercises is found to evoke questioning behavior and to provide resources for answering questions. The exercises are explored as a tool for educational assessment.
Development of Design Skills Through Employment of Open-Ended Problems
Authors: Brock Harvey R. , Condoor Sridhar S. , Burger Christian P.
Published: March 2021

With the recent increased concern about the design and problem solving needs of U.S. industry, and academia’s inability to address them, there has arisen a desire to incorporate open-ended problems in engineering education. In the initial stages most, if not all, real-world engineering problems are ill-defined, and have several acceptable solutions, i.e. they are open ended. Yet, our students get very little practice in finding solutions for this type of problem. Correcting this weakness in engineering curricula is hampered by misconceptions about, and inexperience with, these types of problems. As a consequence, educators often attempt to modify typical well defined example problems by expanding their scope, but still taking care to insure that the solution domains are closely circumscribed and well defined. The goal of this paper is to illustrate the main features of open-ended problems and their utility in design education. Such problems are characterized by incomplete or inconsistent information, no evident solution strategy, non-unique solutions, and often poorly understood goals. A real-world open ended design problem will be contrasted with its’ typical engineering education counterpart. This paper attempts to provide the necessary insights to aid in the formulation and selection of effective open ended problems for use in engineering education.
Experimental and Analytical Study of X-Ray Tube Rotor Dynamics
Authors: Nickel D. A. , Krousgrill Charles M.
Published: March 2021

An X-ray tube rotor has been analyzed, using experimental and numerical methods, as a part of an effort to diagnose an intermittent acoustic noise problem. The type of rotor studied is supported by two solid-lubricated angular contact bearings, and operates in a vacuum.

Experimental studies of rotor vibration were performed using a test fixture with radio frequency proximity sensors. Coast-down studies indicated the presence of both synchronous and sub-harmonic whirl, along with a tendency for the nature of response to change rapidly during operation.

Two ODE (ordinary differential equation) models: a three-dimensional four-degree-of-freedom model and a one-dimensional one-degree-of-freedom model were derived. Large bearing clearances were a significant source of stiffness nonlinearity in both. Direct ODE solution was used to analyze both models. Parametric continuation was also used to find periodic solutions to the one-degree-of-freedom model for different sets of parameter values. The simulations were performed with geometric and stiffness properties representative of the X-ray tube rotor. Small damping was assumed because of the solid lubricant.

Direct ODE solutions showed a variety of synchronous and subharmonic periodic motions. Multi-branch frequency response curves were computed using continuation. Qualitative agreement between experimental and numerical results was obtained in terms of tendency to jump, frequency at which multivaluedness was first observed, and existence of subharmonic solutions.
Dynamics Response of a Hysteretic Structure Under Random Excitations
Authors: Orabi Ismail I.
Published: March 2021

The response of a hysteretic structure under horizontal and vertical random excitations is considered. The excitations are modeled by segments of stationary and nonstationary Gaussian white noise and filtered white noise processes. The linearization technique is used and the moments equations of the responses are evaluated. The transition probability density of the response is described and the associated second moment equations are derived. The transient and nonstationary response statistics for a range of values of parameters are obtained. A Monte-Carlo digital simulation study is performed. The results are compared with the theoretical findings and good agreements is observed. Particular attention is given to the amplification effects of the vertical acceleration. It is shown that the effect of the vertical excitation is usually insignificant, unless the load coefficient is quite large.
On-Line Identification and Location of Rotor Cracks
Authors: Ratan Santosh , Baruh Haim , Rodriguez Jorge
Published: March 2021

A new method is proposed to detect and locate a crack in a rotor system. A vector quantity ‘Residue’ is defined using the measured vibration response of the rotor system and the modeled system matrices. It is shown that the non-zero elements of ‘Residue’ correspond to the nodes encompassing the element carrying the crack. Although, the derivation of ‘Residue’ is based on the linear model of the rotor system, the response due to the non-linearity caused by the breathing of the crack causes only a small amount of contamination. To investigate the robustness of the proposed method, a sensitivity analysis is conducted. It is found that the method could detect a crack of as small depth as 4% of the shaft diameter. The effects of light damping and the order of finite element discretization on the detection result are also investigated, and are found to be small.
Parametrically Excited Nonlinear Two-Degree-of-Freedom Systems With Repeated Natural Frequencies
Authors: Nayfeh A. H. , Chin C. , Mook D. T.
Published: March 2021

The method of normal forms is used to study the nonlinear response of two-degree-of-freedom systems with repeated natural frequencies and cubic nonlinearity to a principal parametric excitation. The linear part of the system has a nonsemisimple one-to-one resonance. The character of the stability and various types of bifurcation are analyzed. The results are applied to the flutter of a simply-supported panel in a supersonic airstream.
Extended Decision Tables for Multistate Fault Tree Synthesis
Authors: Wang J. D. , Liu T. S.
Published: March 2021

This study presents component modeling based on extended decision tables for multistate fault tree synthesis. Events are defined by both qualitative and quantitative forms. Compound functions of subsystems, such as redundancy, are described by virtual transfer components. Editing procedures are implemented to expedite the synthesizing process and prune the generated fault trees. A pressure tank system is employed as an example to demonstrate the proposed mothed.
An Efficient Reliability Technique to Study the Performance of Rocket Motors
Authors: Janajreh Ibrahim M. , Heller Robert A.
Published: March 2021

An efficient reliability technique is developed based on Response Surface Methodology (RSM) in conjunction with the First Order Second Moment (FOSM) reliability method. The technique is applied when the limit state function cannot be obtained explicitly in terms of the design variables, i.e. when the analysis is performed using Finite Element Codes. When compared with exact analysis, results have shown an excellent agreement. Therefore, this technique allows the extension of most Finite Element Codes to account for probabilistic analysis, where statistical variations can be added to the design variables.

An explicit solution for rocket motors consisting of propellant and steel case under environmental temperature variations is compared to the RSM technique. The method is then used for the analysis of rocket motors subjected to two opposite line loads for which the stress analysis is performed using finite element method. Results have shown that the reliability of the motor decreases as the applied load increases or the storage time increases.
Fatigue Analysis of Induction Hardened Pins
Authors: Lindner Mark J. , Elbella Abdalla
Published: March 2021

A generalized procedure was developed to predict fatigue failure in the design of induction hardened pins. Finite element analysis was used to determine the elastic and inelastic strain response at subsurface locations. The finite element mesh was arranged in a layered fashion in which each layer had a unique cyclic stress-strain curve. The procedure incorporated the effects of residual stresses due to induction hardening and used the strain-life approach to determine fatigue life and damage. The areas of predicted failure agreed with those observed in the field.
Crack-Tip Fields of Short Cracks in Bending As Characterized by Two Parameter Criterion
Authors: Zarzour J. F. , Dah-Wei Y. , Kleinosky M. J.
Published: March 2021

Single edge notched bars (SENB), in the bending mode, with a/W ratios ranging from 0.05 to 0.5 were examined for fracture toughness in terms of the J-integral approach. The results indicate that for a/W ratios less than 0.3, there is a significant loss of J-dominance. This loss is attributed to the effect of plastic deformation on the cracked face. For a/W ratios greater than 0.3, J-dominance is maintained into the large scale yielding regime. According to the recently developed two-parameter criterion (J,Q), compressive Q-stress was interpreted as an indication of low crack-tip stress triaxiality for shallow cracks, while positive Q-stress was associated with high crack-tip stress triaxiality for deep cracks. For the material properties and specimen geometries considered herein, a fracture toughness locus was constructed in terms of the (J,Q) parameters for each of the a/W ratios. The overall fracture data are in agreement with those predicted by other approaches and provide a rigorous framework for interpreting the effect of loss of crack-tip constraint in elastic-plastic fracture analyses.
Member Stiffness and Contact Pressure Distribution of Bolted Joints
Authors: Lehnhoff Terry F. , Ko Kwang-Il , McKay Matthew L.
Published: March 2021

Member stiffnesses and the stress distributions in the bolts and members of bolted joints have been calculated for various bolt sizes, as well as thicknesses and materials of the members. The finite element method has been used to calculate the displacements and the stress distributions in the components of the bolted joint. Using axisymmetric elements, the bolted joint was analyzed as a two-dimensional problem. Member stiffness ratios were calculated from the finite element results and compared with those calculated by a commonly used theory. The differences in values were significant (16–30 percent difference) for the assumptions under which the theory was applied. Formulas and dimensionless curves which can be used to estimate the member stiffness ratios for several kinds of bolted joints are presented.