bluuebunny/crossref_metadata_2025 huggingface dataset:
Diet, adiposity, and the gut microbiota from infancy to adolescence: A systematic review
Authors: Vander Wyst Kiley B. , Ortega‐Santos Carmen P. , Toffoli Samantha N. , Lahti Caroline E. , Whisner Corrie M.
Published: February 2021

Early life gut microbiota are affected by several factors that make identification of microbial‐adiposity relationships challenging. This review evaluates studies that have investigated the gut microbiota composition associated with adiposity in infants, children, and adolescents and provides evidence‐based nutrition recommendations that address microbiota‐adiposity links. Electronic databases were systematically searched through January 2020. Eligible studies were published in English and analyzed gut microbiota and adiposity among individuals aged birth to 18 years. Abstracts and full‐text articles were reviewed by three independent reviewers. Of 45 full‐text articles reviewed, 33 were included. No difference in abundance was found for Bacteroidetes (n = 7/15 articles), Firmicutes (n = 10/17), Actinobacteria (n = 8/12), Proteobacteria (n = 8/12), Tenericutes (n = 4/5), and Verrucomicrobia (n = 4/6) with adiposity. Lower abundance of Christensenellaceae (n = 3/5) and Rikenellaceae (n = 6/8) but higher abundance of F. prausnitzii (n = 3/5) and Prevotella (n = 5/7) were associated with adiposity. A lack of consensus exists for gut microbial composition associations with adiposity. A healthy gut microbiota is associated with a diet rich in fruits and vegetables with moderate consumption of animal fat and protein. Future research should use more robust sequencing technologies to identify all bacterial taxa associated with adiposity and evaluate how diet effects these adiposity‐associated microbes.
Effects of message order and active participation on vaccine risk communication
Authors: Okuno Hideo , Satoh Hiroshi , Iitake Chie , Hosokawa Shinichi , Oishi Kazunori , Kikkawa Toshiko
Published: February 2021

Background

“Message order” and “active participation” could be effective as risk communication methods. “Anticipated regret” (AR) has also been recognized as affecting risk perception and vaccine uptake in vaccination risk communication. We aimed to evaluate the effects of message order and active participation and the interactions between these two interventions on AR for vaccination.

Methods

We conducted a 2 (message order: positive‐negative or negative‐positive) × 2 (message calendar: with or without planning) factorial design study among 81 study participants. The effects of message order and active participation of mothers, using a message calendar, were evaluated on mothers’ decision‐making regarding vaccination with Haemophilus influenzae type b vaccine and pneumococcal conjugate vaccine for their children. Participants completed questionnaires to evaluate the AR of infection if unvaccinated (anticipated regret of inaction) and of side effects if vaccinated (anticipated regret of action, ARA) twice: immediately after interventions and 1 month later.

Results

An interaction between message order and active participation was significant with regard to anticipated regret of inaction immediately after interventions (P = 0.01), but this effect disappeared 1 month after interventions. The message order showed no main effect with regard to ARA. However, the main effect of active participation was marginally significant with regard to ARA 1 month after intervention (P = 0.09); AR over vaccine side effects was lower when vaccination was planned than in the condition without planning.

Conclusions

The effect of message order was hardly detectable in a clinical setting. However, active participation induced by planning may affect AR. Further studies are needed to evaluate the effect of active participation in decision‐making for vaccination.
Quality of life in long term survivors of pediatric intestinal transplantation compared with liver transplantation and home parenteral nutrition: A prospective single‐center pilot study
Authors: Proli Francesco , Metou‐Lopes Adamadia , Ayachi Amel , Rossi Matilde , D’Arcangelo Giulia , Faragalli Andrea , Lambe Cécile , Talbotec Cécile , Goulet Olivier , Chardot Christophe , Lacaille Florence
Published: February 2021

Health‐related quality of life (HRQOL) after intestinal transplantation (IT) is important, as many psychological troubles have been reported in these patients on the long term. Our aim was to assess and compare HRQOL of patients after IT to patients after liver transplantation (LT) or on home parenteral nutrition (HPN) for intestinal failure. A cross‐sectional study included patients and their parents between 10 and 18 years of age, on HPN for more than 2 years, or who underwent IT or LT, with a graft survival longer than 2 years. Quality of life was explored by Child Health Questionnaire. Thirteen children‐parents dyads after IT, 10 after LT, and eight children on HPN completed the survey. Patients were a median age of 14 years old, a median of 10 years post‐transplantation or on HPN. Patients after IT scored lower than patients after LT or on HPN in “social limitations due to behavioral difficulties” and in “behavior.” They scored higher than those on HPN in “global health.” Parents of children after IT scored lower than those after LT in many domains. No relevant correlation with clinical data was found. Our study showed the multi‐level impact of IT on quality of life of patients and their parents. It highlights the importance of a regular psychological follow‐up for patients, but also of a psychological support for families. Helping the patients to overcome the difficulties at adolescence may improve their mental health in adulthood.
Soil mutualisms potentially determine the reintroduction outcome of an endangered legume
Authors: Becknell Rachel E. , Showalter Kelli G. , Albrecht Matthew A. , Mangan Scott A.
Published: February 2021

Successful recovery of populations of endangered plant species requires conservation of existing populations as well as the creation of new populations through reintroduction. However, the ecological requirements of many rare plant species are poorly understood, and many reintroduced populations are unable to survive long term. Effective reintroduction of rare plants, such as the federally endangered Astragalus bibullatus, may depend on developing a greater understanding of the symbiotic relationships that these rare species form with the soil microbiome, as well as determining whether these are species‐ and site‐specific. We inoculated seedlings of A. bibullatus, its more widespread congener A. tennesseensis, and the common grass Schizachyrium scoparium, with soil biota collected from five glade sites where A. bibullatus is historically present (HP) and four glade sites where the species is historically absent (HA). We examined the impacts of soil microbes from HP and HA glade sites as well as from each species on the growth, arbuscular mycorrhizal fungi (AMF) colonization, and formation of root nodules of A. bibullatus and its congener A. tennesseensis. Astragalus bibullatus grew significantly larger when grown in soil from HP glade sites compared to its growth in soil from HA glade sites. Astragalus bibullatus also formed significantly more root nodules when grown in HP soil, but no difference was detected in AMF colonization based on glade history. Our findings suggest that the successful establishment of rare plant species may depend on species‐specific associations with soil mutualists such as nitrogen‐fixing rhizobial bacteria and should consider whether essential microbes are present.
Fine root production, turnover ofReaumuria songaricaand soil carbon and nitrogen in Alxa steppe desert ofNWChina
Authors: Ma Xiong‐zhong , Wang Xin‐ping , Jin Yan‐xia , Zhang Ya‐feng
Published: February 2021

Variations of fine root production and turnover of the dominant shrubs associated with soil carbon (C) and nutrients are of key importance for evaluating desert ecosystem sustainability. Here we examined fine root production and turnover rate ofReaumuria songaricain Alxa steppe desert of northwestern China through sequential coring, ingrowth cores, and mesh‐bag methods, and then assessed soil C and nitrogen (N) stock and its correlation with fine root and leaf litter input. Results showed that fine root production and turnover rate were closely related to soil water content. Fine root production density and turnover rate ofR. songaricawere 386.8 g m−2and 2.4 yr−1, respectively. Annually, fine root and leaf litter ofR. songaricainput 126.3 g C m−2and 4.7 g N m−2to soil. Soil organic C and N under shrub canopies increased substantially, which promoted the heterogeneity of soil properties and is considered as an important mechanism underlying the restoration of degraded sandy lands.
Patterns of conifer invasion following prescribed fire in grasslands and oak woodlands of Redwood National Park, California
Authors: van Mantgem Phillip J. , Wright Micah C. , Engber Eamon A.
Published: February 2021

The invasion, or “encroachment,” of native conifers commonly occurs in the absence of frequent fire in deciduous woodlands and grasslands of the Pacific Northwest, USA. To effectively target restoration activities, managers require a better understanding of the outcomes of prescribed fire and the spatial patterns of conifer invasions. We examined the duration of prescribed fire effectiveness for managing conifer invasions, as well as multiple site characteristics (including distance to potential seed trees, prescribed fire history, and topographic variables) that influenced conifer invasions following fire in grassland and oak woodland communities in the Bald Hills of Redwood National Park, California. Prescribed fire substantially reduced counts of small conifers (<0.91 m in height), but reinvasion was rapid for sites ≤75 m from the forest edge, returning to pre‐fire levels by 2 years post‐fire. Following prescribed fires, the presence of conifers was largely determined by the proximity of overstory trees, with more than 95% of conifer seedlings (stems <1.37 m in height) found within 44 m of an overstory conifer. Number of fires and years since the most recent fire were not strongly related to counts of conifer seedlings and density of conifer saplings (stems from 0.1 to 10 cm diameter at breast height, 1.37 m). Our results suggest that in the Bald Hills vulnerability to conifer invasion is principally a function of proximity to seed sources, and the frequent application of prescribed fire or surrogate treatments are needed to prevent conifer seedlings from attaining fire‐resistant sizes.
The Unexpected Legacy of Charles Tilly: Relational Work, Inequality, and Economic Sociology1
Authors: Bandelj Nina
Published: February 2021

This essay is part of a special section entitled “Legacies of Sociology’s Past." My work addresses the contributions of Charles Tilly.
Racial Politics and the Presidency: Analyzing White House Visits by Professional Sports Teams
Authors: Bailey Kendall L. , Trantham Austin
Published: February 2021

Objectives

This article investigates the impact of racial politics on White House visits by professional sports teams. Given increasing political polarization and varying racial compositions of major sports leagues, we hypothesize increased visits and objections over time while the prevalence of nonwhite players in a league detrimentally affects visits with Republican presidents and objections to visiting with them.

Methods

Utilizing an original data set, we employ binary logistic regression to examine White House visits and objections by champions of six major professional sports leagues between 1993 and 2019.

Results

We find (1) increased visits and objections over time; (2) a negative relationship between a league's nonwhite composition and the likelihood of a White House visit; and (3) a positive relationship between a league's nonwhite composition and objections to visits with Republican presidents.

Conclusions

This research provides a more nuanced understanding of how racial politics influences the relationship between the American presidency, society, and culture.
Developing a rapid and highly efficient cowpea regeneration, transformation and genome editing system using embryonic axis explants
Authors: Che Ping , Chang Shujun , Simon Marissa K. , Zhang Zhifen , Shaharyar Ahmed , Ourada Jesse , O’Neill Dennis , Torres‐Mendoza Mijael , Guo Yinping , Marasigan Kathleen M. , Vielle‐Calzada Jean‐Philippe , Ozias‐Akins Peggy , Albertsen Marc C. , Jones Todd J.
Published: February 2021

Cowpea (Vigna unguiculata (L.) Walp.) is one of the most important legume crops planted worldwide, but despite decades of effort, cowpea transformation is still challenging due to inefficient Agrobacterium‐mediated transfer DNA delivery, transgenic selection and in vitro shoot regeneration. Here, we report a highly efficient transformation system using embryonic axis explants isolated from imbibed mature seeds. We found that removal of the shoot apical meristem from the explants stimulated direct multiple shoot organogenesis from the cotyledonary node tissue. The application of a previously reported ternary transformation vector system provided efficient Agrobacterium‐mediated gene delivery, while the utilization of spcN as selectable marker enabled more robust transgenic selection, plant recovery and transgenic plant generation without escapes and chimera formation. Transgenic cowpea plantlets developed exclusively from the cotyledonary nodes at frequencies of 4% to 37% across a wide range of cowpea genotypes. CRISPR/Cas‐mediated gene editing was successfully demonstrated. The transformation principles established here could also be applied to other legumes to increase transformation efficiencies.
Finding Minimum Cost Tool Grouping Schemes on Machining Systems
Authors: Yip-Hoi Derek , Dutta Debasish
Published: February 2021

Changing worn tools is a major concern in planning operations on machining systems. Strategies for replacing tools range from changing each tool as it reaches its projected tool life, to changing all tools when the tool with the shortest life on the machining system is expended. Intermediate strategies involve changing tools in groups. Each of these strategies has two cost components associated with it: (1) the cost of lost production due to machine tool stoppage, and (2) the cost of unused tool life. The best tool grouping strategy minimizes the combined cost of lost production. In this paper we present an approach for finding good tool grouping strategies from inputs that include the tool utilization for a given machining application, and the tooling and machining system costs. A genetic algorithm is used as the underlying optimization paradigm for finding the minimum cost strategy. An example is presented for a part produced on a machining center.
System Cost Based Material Selection for Engineering Thermoplastics
Authors: Beiter Kurt A. , Ishii Kosuke
Published: February 2021

This paper describes system cost based material selection, a computerized procedure for considering mechanical requirements, manufacturing costs, and material selection in the design of injection molded engineering thermoplastic parts. The benefit of this approach is the simultaneous consideration of material choice and part geometry on estimated manufacturing cost during candidate design selection. Using cost as a material selection measure permits the examination of system cost as a function of application requirements. The current implementation uses the allowable deflection of a flat plate and equivalent system stiffness as performance measures. Manufacturability concerns include required part thickness and gating scheme to adequately mold the part, production costs for meeting part tolerance requirements, and a resulting cycle time based on part cooling time estimates. Part manufacturing cost includes material cost, cycle time, and production costs. An example of a desktop printer shows the merits of this approach.
Constraint Management in Distributed Product Models
Authors: Henderson David L. , Anderson David C.
Published: February 2021

Computer models for complex mechanical products are often distributed among design team members who use disparate software tools. Communication between these tools has previously been limited to occasional file transfer. However, recent research has begun to allow software applications to communicate automatically to maintain the integrity of the evolving product model. Constraint satisfaction plays an important role in maintaining design integrity. This paper describes a methodology for representing and satisfying constraints in distributed design environments. The methodology employs a propagation method that allows the solution steps to be posed as messages between applications. The propagation methods also facilitate support for a broad range of object and constraint types. We show how the method can be applied to both algebraic and geometric constraints. We also describe a method called symbolic propagation that is used for solving coupled and underconstrained systems. A distributed assembly design system that was implemented to demonstrate and validate the methods is also described.
An Integrated Simulation-Based Design and Manufacturing Environment Using Intranet and CORBA
Authors: Hardee Edwin , Tsai Chung-Shin , Choi Kyung K.
Published: February 2021

An intranet-based tool for integrating an enterprise-wide simulation-based design and manufacturing environment for mechanical systems is presented. The tool is invoked as a Java applet from a web page. Users can browse global product model data from the applet and retrieve and store product data between the global product data server (called the Design Data Server) and their local workspaces. Network connections are based on the CORBA standard. This environment enables the achievement of concurrent engineering goals. It gives the members of an enterprise-wide product development team a convenient, uniform interface to the global product data from different platforms. It allows their various simulation and modeling tools on the different platforms to interoperate through the Design Data Server.
INTERPRET: A Communication Tool With Customers via Public Network
Authors: Vajna Sándor , Schabacker Michael
Published: February 2021

INTERPRET is an intelligent product catalogue which allows a customer to select online exactly his component being supported by the knowledge provided by the supplier. Additionally, the customer can insert both the actual geometry into his own design as well as dispositive data file into his administrative data processing system.

Main focus of INTERPRET is the electronic handling of different business processes on heterogeneous computer systems (the so-called telecommerce). The Internet serves here as a communication platform to the design of the desired worldwide virtual production system (Kroll, 1994). The availability of this low-priced solution for each enterprise facilitates the fast and flexible design of virtual production communities (Davodow, Malone, 1993).
A Computable Fastener Representation to Support Computer-Aided Configuration Design for the Life Cycle
Authors: Harper Brian , Siddique Zahed , Rosen David
Published: February 2021

Most of a product’s life-cycle characteristics are determined during the configuration design stage, when the product’s components are selected and arranged spatially and logically. One set of choices that determines many life-cycle characteristics is fastener type selection. In this paper, an assembly modeling representation is presented that supports changes in fastener types and fastening mechanisms while maintaining consistent degrees-of-freedom among fastened components. A fastening mechanism template and a corresponding instantiation algorithm have been developed for tensile-compressive fasteners. The template consists of four main elements: an assembly representation template, CSG tree fragments (to allow geometry construction), geometric constraint templates, and a parametric relationship template to integrate analysis equations into fastener models. Each particular fastener type is modeled by a specific template that is developed manually using the general template as a guide. The instantiation algorithm maps a particular fastening template onto an existing assembly model (assemblies, components, geometry, and mating relationships) in order to add fasteners to a product. A similar fastener substitution algorithm enables the replacement of one fastener type with another. The use of the algorithms is illustrated in the configuration design of an automotive center console. The paper concludes with a brief demonstration of how fastener selection affects life-cycle product characteristics.
Global Kinetics of the Thermal Decomposition of Materials
Authors: Missoum Azzedine , Gupta Ashwani K. , Chen Jianrong
Published: February 2021

Results on the thermal destruction behavior during the decomposition of cellulose under controlled conditions are presented. Thermogravimetric (TGA) and Differential Scanning Calorimetry (DSC) tests have been carried out on the celluose samples under conditions of various heating rate and surrounding gas environment. Pyrolysis times were also measured for different size particles having different moisture contents in a controlled mixing history reactor (CMHR). The global decomposition kinetics were investigated and it was found that the decomposition process is shifts to higher temperatures at higher heating rates as a result of the competing effects of heat and mass transfer, product diffusion and the reactions kinetics. The Arrhenius parameters for pyrolysis were determined using a first order decomposition reaction of the type, dm = −km dt. It was found that the activation energy, heat of pyrolysis and char yield are a strong function of the heating rate. An increase in heating rate from 5 to 60°C/min resulted in a change of activation energy from 204.19 to 138.31 kJ/mole °C. This heating rate dependence of the kinetics is discussed. The overall decomposition process of the examined materials is generally endothermic. In general, heat transfer, mass diffusion, product evolution, heating rate, temperature and environment are the parameters that control the decomposition process. It was also shown that heat transfer and mass transport have the most effects on the decomposition process.
Fine Particle Removal Using High Frequency Acoustic Streaming
Authors: Busnaina Ahmed A.
Published: February 2021

Liquid-based cleaning is extensively used in the semiconductor and other industries affected by contamination for the removal of particulate contamination. One of the widely used wet-cleaning processes is the megasonic cleaning. The megasonics term is used in industry to refer to frequencies near 1 MHZ. Megasonic cleaning techniques used today in industry were first presented by RCA scientists [1,6,7]. McQueen [4,5] identified the effect of the acoustic boundary layer and its role in the removal of small particles at high frequency. Kashkoush, Busnaina et al [8–11] studied ultrasonic and megasonic particle removal, focusing on the effects of acoustic streaming. They showed that removal percentage increased with power. Their results also indicated different removal efficiencies for polystyrene latex (PSL), silica (SiO2) and silicon nitride (Si3 N4) particles. Megasonic cleaning using SC1 and SC2 chemistry has been shown to be very effective by Syverson, et. al. [12]. They also showed that the removal efficiency increased with power up to a 150 W (maximum power available). Wang et al [13] also showed that power had the greatest influence on the removal efficiency up to a maximum power available (150 W). These results are consistent with what was observed by Kashkoush, Busnaina and Gale [12,13]. However, Gale and Busnaina [14–17], using higher power megasonics up to 800 W, showed that the highest removal efficiency occurs at an optimum power (500–600 W) above which it decreases slightly. They also showed that megasonic input power has the greatest influence on particle removal efficiency as compared to solution temperature, both in water and in SC1 solution. They also showed that SC1 removes particles more efficiently than DI water, particularly at lower megasonic powers. But they also showed that it was still possible to achieve 100% removal in DI water under the proper conditions.
Concurrent Engineering Education: An Example Project
Authors: Biswas Arunava , Kinzel Gary L. , Li Chiu Yeung , Liu Ting
Published: February 2021

The intent of this paper is to give the background and details of a project using the concepts of concurrent engineering and design for manufacturing in an educational framework. The project involves the design and production of parts that have simple 2-d shapes with slots. These can be fit together to create a variety of 3-d shapes and figures. These are like children’s toy “puzzle” pieces (building blocks) that can be disassembled and reassembled into new figures over and over. The parts have been produced using the machined mold on a small injection molding machine. This paper discusses the execution of the project from the concept to the design to the production stages. Design for Manufacturing education will be highlighted through this interesting example project.
Motion Simulation of Gears and Cams Using Working Model
Authors: Wang Shih-Liang
Published: February 2021

Motion simulation of mechanism of line contact like gears and cams has been difficult in the past. With Working Model, NURBS based complex geometry can be modeled fairly easily, and its simulation engine can animate this type of mechanism accurately. In this paper several Working Model files are developed for visualization and analysis. An algorithm to generate involute gear tooth profile is introduced in this paper for the involute and a portion of non-involute surface.
The Optimization of Threshold Value of the Relational Degree in Grey Theory Method for Fault Diagnosis
Authors: Liu Y. H. , Ma F.
Published: February 2021

In this paper, optimization of the threshold value of the relational degree in Grey Theory method for fault diagnosis is considered. With an emphasis on minimizing both the error rate and miss rate of fault diagnosis, new ideas are proposed to determine the optimal range of the threshold value. A practical example is given to demonstrate the feasibility of the proposed method.
Effect of Multimaterial Layering on the Response of a Generic Hull Structure
Authors: Gupta Aaron D. , Meyer Christopher
Published: February 2021

The dynamic response of a basic, generic, multilayered, composite vehicle hull with a large, circular opening for the turret assembly has been compared with that of an equivalent single-layer, basic metallic hull with identical geometry to assess the influence of a multilayered, composite armor panel structure on the modal response. Both models, without the engine block, mountings, transmission, and base support system consisting of tracks, wheels, sprockets, torsion bars, etc., were generated using PATRAN 3 to facilitate computational modal analysis and comparative evaluation of the influence of multilayered construction on the free vibrational response.
Computer Applications in Rapid Prototyping: Overview and Case Study
Authors: Petersen Harry C. , Markowski Andrzej
Published: February 2021

Rapid prototyping, the rapid conversion of computer designs into physical products, is a valuable tool for design, sales, communication, and limited production. This paper presents an overview which describes various systems of both additive and subtractive rapid prototyping. Computer applications, steps, and formats are introduced. A case study outlines new coursework which has been developed at Mankato State University to teach these basic principles and computer applications. Internet resources are reviewed, including vendors, professional societies, and universities which can help with questions and decisions about rapid prototyping applications.
Hint-Based Reasoning for Feature Recognition: Status Report
Authors: Han JungHyun , Regli William C. , Brooks Steve
Published: February 2021

This paper presents an overview of hint-based feature recognition algorithms. A hint is a piece of information that implies a feature’s existence. Geometric completion procedures start from the hint instances, perform extensive geometric reasoning and finally construct feature instances. This paper describes the IF2, F-Rex and FBMach systems, and shows that the hint-based reasoning can deal with complex feature intersections.
Automatic Regular Hexahedral Mesh Generation by Regular Volume Decomposition
Authors: Shih Bih-Yaw , Sakurai Hiroshi
Published: February 2021

A method has been developed to generate regular hexahedral meshes automatically from arbitrary solid models by volume decomposition. This method first decomposes a solid model having a complex shape into volumes having simple shapes. Then, shape-specific meshing methods like mapping are applied to generate regular hexahedral meshes from these volumes. Finally, all regular hexahedral meshes of these volumes are combined into a regular hexahedral mesh of the original solid model. Thus the method generates regular hexahedral meshes automatically in a way similar to the way a human does interactively. This is in contrast to the previous methods of automatic hexahedral mesh generation, which try to generate hexahedral meshes from solid models directly.
Best Fit Uncertainty Analysis for Computing Geometric Tolerances
Authors: Yau Hong-Tzong
Published: February 2021

In computing geometric tolerances using point data from a coordinate measuring machine (CMM), a best fit process needs to be carried out to bring the measurement data to the coordinate system of the substitute geometry. The measurement data does not precisely conform to the substitute geometry. It involves errors from machining as well as measurement itself. With this error-carrying measurement data, the best fit result contains uncertainties which in turn reduce the accuracy of the evaluated tolerances. In this paper, a model is proposed to estimate the best fit uncertainties caused by surface deviation, point location, and CMM sample size. The model was verified by simulation and experiment. To explore factors that affect the uncertainty variations, geometric variables that influence the uncertainties were first studied. Then, to understand the effect of point location on the uncertainty, optimization using the conjugate gradient method was developed to find the best measurement locations by minimizing the total uncertainties. In addition, simulations showed that the uncertainty is inversely proportional to the squared root of the number of points. This result can be used to predict the CMM sample size that will control the best fit uncertainty under certain tolerances.
Nonlinear Integer, Discrete and Continuous Optimization Using Adaptive Range Genetic Algorithms
Authors: Arakawa Masao , Hagiwara Ichiro
Published: February 2021

Genetic algorithms are effective algorithms for large scaled combinatorial optimization. They are potentially effective in integer and discrete optimization. However, as they are not well coded to its tedious expression in converting chromosomes to design variables, we need to do some special efforts to overcome these flaws. In the proposed method, it automatically adapts searching ranges according to the situation of the generation. Thus, we are free from these flaws. Moreover, we don’t have to give too many genes to chromosome, we can save computational time and memory and the convergence becomes better. In this paper, we combine the proposed integer and discrete adaptive range genetic algorithms and adaptive real range genetic algorithms which we presented in the previous studies, and present an extended genetic algorithms method. We applied the proposed method to well-known test problems, compare the results with the other methods and show its effectiveness.
Feature-Based Gearbox Design
Authors: Heikkinen Ari , Korpela Tapio , Leinonen Tatu
Published: February 2021

The Laboratory of Machine Design of the University of Oulu has defined and implemented a design and manufacturing system for a gear manufacturer in co-operation with the company’s own staff. The parts of gear train, such as shafts and gear wheels, are designed by an application program included in a two-dimensional system and the gear housing is designed by a commercial three-dimensional feature-based system. A shaft design and manufacturing system has been discussed in previous papers produced in connection with this project (Korpela, T., et al. 1995, Heikkinen, A., et al. 1996). The tool used for gear housing design and manufacturing have been tested during the past year, and experiences with this CAD system are recounted here. It has been found that the design features which implement the functional requirements of gear construction are different from the features which support the manufacturing processes.
Mathematical Programming Neural Networks (MPNN) for Mechanism Design
Authors: Li Jianmin , Gupta Krishna C.
Published: February 2021

The prevalent Mathematical Programming Neural Network (MPNN) models are surveyed, and MPNN models have been developed and applied to the unconstrained optimization of mechanisms. Algorithms which require Hessian inversion and those which build up a variable approach matrix, are investigated. Based upon a comprehensive investigation of the Augmented Lagrange Multiplier (ALM) method, new algorithms have been developed from the combination of ideas from MPNN and ALM methods and applied to the constrained optimization of mechanisms. A relationship between the weighted least square minimization of design equation error residuals and the mini-max norm of the structure error for function generating mechanisms is developed and employed in the optimization process; as a result, the computational difficulties arising from the direct usage of the complex structural error function have been avoided. The paper presents relevant theory as well as some numerical experience for four MPNN algorithms.
A Unified Formulation for Swept Volume and Robot Workspace Analyses
Authors: Abdel-Malek Karim , Yeh Harn-Jou , Ruwady Rabeeh
Published: February 2021

This paper presents a unified formulation for the generation of mechanical manipulator workspaces, and the representation of the volume of an entity swept along another. A constraint function is developed and its Jacobian is studied. The analysis is based upon a row-rank deficiency criteria of the non-square constraint Jacobian. Singular geometric entities inside the resulting volume are identified and parametrized. These entities are characterized by a set of singular generalized coordinates (parameters), when substituted into the constraint vector function yield parametric equations. Singular geometric entities are assembled and intersected to identify sub-entities that are boundary to the volume. A local perturbation method is applied to determine which sub-entities are boundary to the workspace. Several examples are presented to verify the formulation.
Function-Costing Applied to Brushless D.C. Permanent Magnet Motors
Authors: Chidambaram Bala , Agogino Alice M.
Published: February 2021

Function-costing is a cost-estimation hypothesis that helps designers estimate costs from a product’s specifications. It is surmised, that for a class of products, the relationship between cost and the primary function can be captured in a mathematical relation. It proceeds on the basis that in a free market, the lowest cost of a product will emerge over time and this cost can be roughly approximated from the product’s primary performance function. In this paper, we validate the function-costing hypothesis for Brushless D.C. permanent magnet motors (BDCPMMs). The principal function of these motors is to provide torque and the peak torque is chosen as the primary performance function. From the cost-peak torque data of a family of eight BDCPMMs produced by a motor manufacturer, we obtain a regression-based cost-estimation relation based on the function-costing hypothesis. The manufacturing processes involved in the BDCPMM construction are studied. A detailed cost-estimation function — in terms of the BDCPMM design variables — is developed using the principle of similarity and the cost data from the eight motors. The costs of constructing a motor for different peak torques is then obtained from a nonlinear discrete optimization formulation (minimum cost objective), which is solved using a genetic algorithm. These costs compare well with the costs predicted by function-costing and validate the hypothesis for BDCPMMs. Finally, we investigate potential applications of function-costing to BDCPMM redesign.
Optimal Fastener Pattern Design Considering Bearing Loads
Authors: Chickermane Hemant , Gea Hae Chang , Yang R. J. , Chuang C. H.
Published: February 2021

In many engineering structures, failure occurs either at the connection itself or in the component at the point of attachment of the connection. To extend the service life of the structure it is important to ensure that the loads borne by the connections are distributed as uniformly as possible. This would also minimize the possibility of localized high stress regions within the component. In this work a topology optimization based approach has been developed to incorporate fastener load constraints into a problem formulated for optimal location of fasteners. The computational results indicate that it is effective in reducing the maximum fastener loads without compromising on the overall stiffness of the structure.
Computerized Finite Element Mesh Generation in Hypoid Gears
Authors: Simon Vilmos V.
Published: February 2021

A method has been developed for the automatic finite element discretization of the pinion and the gear of a Gleason type hypoid gear pair. The numbers and sizes of elements can by arbitrarily chosen in the main directions and in the different regions of the teeth in order to get a finer mesh where extreme values of stresses are expected or previously calculated. The method includes the identification of each element by its number, the definition of element topology, the calculation of the nodal coordinates, and the specification of the boundary conditions. The main part of the method is the calculation of the nodal coordinates, based on the real tooth geometry of the pinion and gear teeth. The determination of the tooth flank and the tooth fillet surface is based on the kinematics of the manufacture and on the applied machine tool settings. On the basis of the presented theory the corresponding computer program has been developed. By using this program the grid mesh in a pinion and in a gear of a hypoid gear pair is generated and presented.
Implicit Integration of the Equations of Multibody Dynamics in Descriptor Form
Authors: Haug Edward J. , Iancu Mirela , Negrut Dan
Published: February 2021

An implicit numerical integration approach, based on generalized coordinate partitioning of the descriptor form of the differential-algebraic equations of motion of multibody dynamics, is presented. This approach is illustrated for simulation of stiff mechanical systems using the well known Newmark integration method from structural dynamics. Second order Newmark integration formulas are used to define independent generalized coordinates and their first time derivative as functions of independent accelerations. The latter are determined as the solution of discretized equations obtained using the descriptor form of the equations of motion. Dependent variables in the formulation, including Lagrange multipliers, are determined to satisfy all the kinematic and kinetic equations of multibody dynamics. The approach is illustrated by solving the constrained equations of motion for mechanical systems that exhibit stiff behavior. Results show that the approach is robust and has the capability to integrate differential-algebraic equations of motion for stiff multibody dynamic systems.
AutoCam: A Modular Decision Support System for the Design of Cam Mechanisms
Authors: Shooter Steven B. , Reinholtz Charles F.
Published: February 2021

Good engineering practice requires designers to incorporate knowledge, processes and skills to produce a superior product. Each stage of the product realization process requires that the designer utilize available resources to make sound engineering decisions in a timely manner. Much of the research on engineering design has focused on formulating general models for the design process. However, it has been shown that these models are rarely used by engineers in practice. This paper advances the concept that useful design models and the resulting support systems must include methodologies that are particular to a given field or type of design in an overall design methodology framework. The inclusion of these knowledge-domain-dependent methodologies provides a complete framework for the greatest utility to the designer. The paper then describes a decision support system, AutoCam, that embodies these principles for assisting designers in the process of synthesizing cam mechanisms. AutoCam is a comprehensive, modular computer tool that is integrated with a PC-based CAD package to assist the designer throughout the design process, from the problem confrontation, through the formulation of objectives and establishing specifications, and synthesizing the resulting cam profile. While several software programs are available for synthesizing a cam profile from a given motion program, no other current package assists the designer with the complete process of cam mechanism design. AutoCam provides a design model that incorporates a detailed methodology with background information and analytical tools for design.
A System Level Approach to the Design of an Industrial Ecosystem
Authors: Bailey Reid , Allen Janet K. , Bras Bert , Mistree Farrokh
Published: February 2021

Industrial ecology is a nascent concept in which systems of industries work together to reduce their net negative environmental impact. The work in this paper represents an initial step towards the advancement of industrial ecology through quantitative analysis. A system dynamics model of an existing industrial ecosystem is developed in STELLA® and used to represent the system level behavior. A design tool, the Robust Concept Exploration Method (RCEM), that has been used previously for more traditional design problems, e.g., engine design and airplane design, is successfully applied to the system level design of an industrial ecosystem. The results in this paper are intended to provide support for decision makers in complex industrial ecosystems and, more importantly, to increase the knowledge about designing industrial ecosystems. As the concept of industrial ecology progresses, the analysis of ecosystems will become more complex, increasing the need for design at the system level to be addressed with tools such as the RCEM.
Geometric Abstractions to Support Contact Based Disassembly Evaluation
Authors: Shyamsundar N. , Gadh Rajit
Published: February 2021

Determining whether an assembly can be constructed from its components at the design stage results in reduction of assembly problems downstream. One approach to determine if an assembly can be constructed is to perform a disassembly evaluation of the assembly’s geometric model. Abstractions derived from the geometric model may be used to evaluate the disassembly sequence. This paper presents two abstractions to support the disassembly analysis: 1) the Assembly Topology Graph (ATG), and 2) the set of boundary components.

The first abstraction, the ATG, is a graph whose nodes represent the components in the assembly, and whose edges represent a non-null intersection of the convex hulls of component pairs. The second abstraction, the set of boundary components, represents the set of components that intersect the boundary of the assembly which is the convex hull of the assembly. The use of the abstractions in determining the validity of the assembly is discussed in the paper.
Improving the Efficiency of Simulated Annealing Optimization Through Detection of Productive Search
Authors: Szykman Simon , Schmidt Linda C. , Shetty Harshawardhan
Published: February 2021

The popularity of simulated annealing for engineering design applications has grown in recent years, increasing the need for new techniques that improve algorithm performance. Simulated annealing is a time-consuming, iteration-intensive algorithm. One area of algorithm enhancement with high potential impact is the development of methods for improving the algorithm by reducing the amount of wasted or non-productive search. This paper presents an approach to detection of productive search based on statistical process control (SPC) concepts. The proposed Detection of Productive Search (DPS) annealing schedule is compared to three other viable schedules using a 100-city traveling salesman problem. The DPS schedule produces results on par with the best from the more traditional schedules but does so with significantly fewer iterations.
Weight Optimization of Transmission Towers
Authors: Jonsson Magnus Thor , Gudmundsson Ketill H.
Published: February 2021

This paper presents a new approach to the minimum weight optimization of transmission towers, which consists of formulating the optimization problem in a net weight objective function with no constraints. Genetic algorithms are employed to perform the optimization. Instead of using the well known penalty function method to account for design constraints, the constraints are integrated in to the objective function. By selecting cross-sections inside the objective function ensures that the structure, being optimized, is always in full compliance with standard codes of practice for strength assessment of transmission towers.

The paper is primarily concerned with practical aspects of transmission tower design and the method is presented with examples based on accepted codes of practice and realistic tower designs. The problem is formulated for a full size transmission tower, where selected portions of tower topology and geometry are optimized, including a cross-sectional optimization from a set of commercially available steel sections.
Edges of Regression and Limit Normal Point of Conjugate Surfaces
Authors: Chen Ningxin
Published: February 2021

The present paper utilizes the basic theory of the envelope surface in differential geometry to investigate the undercutting line and the contact boundary line on the conjugate surfaces. It is proved that the edges of regression of the envelope surfaces are the undercutting line and the contact boundary line in theory of gearing respectively. Two groups of equations for the undercutting and the contact boundary lines of the conjugate surfaces are developed based on the definition of the edges of regression in differential geometry. The geometric meaning of Wildhaber’s concept of the limit normal point is explained. Numerical examples are taken for illustration of the above-mentioned concepts and equations.
Determination and Analysis of Pinion Mismatch for Hypoid Drives
Authors: Zhang Yi , Wu Zhi , Li Nai-Yi
Published: February 2021

This paper presents an approach for the determination of conjugate pinion tooth surfaces of hypoid drives and the analysis of pinion mismatch. The conjugate pinion tooth surface is compared with the tooth surface of the pinion manufactured by the machine tool settings obtained by the local contact synthesis. The analysis of the mismatch provides a quantitative verification of the pinion surface modifications and complements the existing tooth contact analysis. A numerical example is included in the paper to demonstrate the analysis of pinion mismatch and tooth contact.
Dynamics Modeling of Elastic Multibody Systems Using Kane’s Method As Applied to a Flexible Robot
Authors: Meghdari Ali , Fahimi Farbod
Published: February 2021

Generalization of Kane’s equations of motion for elastic multibody systems is considered. Initially, finite element techniques are used to generate the elastic form of generalized coordinates. Then, the number of elastic coordinates are reduced by the component mode synthesis. Finally, Kane’s method is applied to obtain the equations of motion of such systems. Using this method, dynamic model of an elastic robot with one degree of freedom is presented.