bluuebunny/crossref_metadata_2025 huggingface dataset:
Different lactic acid bacteria and their combinations regulated the fermentation process of ensiled alfalfa: ensiling characteristics, dynamics of bacterial community and their functional shifts
Authors: Bai Jie , Ding Zitong , Ke Wencan , Xu Dongmei , Wang Museng , Huang Wenkang , Zhang Yixin , Liu Fang , Guo Xusheng
Published: March 2021

The objectives of this study were to investigate the adaptation and competition of Lactobacillus plantarum, Pediococcus pentosaceus and Enterococcus faecalis inoculated in alfalfa silage alone or in combination on the fermentation quality, dynamics of bacterial community, and their functional shifts using single‐molecule real‐time (SMRT) sequencing technology. Before ensiling, alfalfa was inoculated with L. plantarum (Lp), P. pentosaceus (Pp), E. faecalis (Ef) or their combinations (LpPp, LpEf, LpPpEf) and sampled at 1, 3, 7, 14 and 60 days. After 60‐days fermentation, the Lp‐, Pp‐ and LpPp‐inoculated silages had lower pH but greater concentrations of lactic acid were observed in Pp, LpEf and LpPpEf‐inoculated silages. The inoculants altered the keystone taxa and the bacterial community dynamics in different manners, where L. plantarum, Weissella cibaria and L. pentosaceus dominated the bacterial communities after 14 days‐fermentation in all treatments. The silages with better fermentation quality had simplified bacterial correlation structures. Moreover, different inoculants dramatically changed the carbohydrate, amino acid, energy, nucleotide and vitamin metabolism of bacterial communities during ensiling. Results of the current study indicate that effect of different inoculants on alfalfa silage fermentation was implemented by modulating the succession of bacterial community, their interactions and metabolic pathways as well during ensiling.
A comprehensive library of fluorescent constructs of SARS‐CoV‐2 proteins and their initial characterisation in different cell types
Authors: Miserey‐Lenkei Stéphanie , Trajkovic Katarina , D'Ambrosio Juan Martín , Patel Amanda J , Čopič Alenka , Mathur Pallavi , Schauer Kristine , Goud Bruno , Albanèse Véronique , Gautier Romain , Subra Melody , Kovacs David , Barelli Hélène , Antonny Bruno
Published: March 2021

Background Information

Comprehensive libraries of plasmids for SARS‐CoV‐2 proteins with various tags (e.g., Strep, HA, Turbo) are now available. They enable the identification of numerous potential protein–protein interactions between the SARS‐CoV‐2 virus and host proteins.

Results

We present here a large library of SARS CoV‐2 protein constructs fused with green and red fluorescent proteins and their initial characterisation in various human cell lines including lung epithelial cell models (A549, BEAS‐2B), as well as in budding yeast. The localisation of a few SARS‐CoV‐2 proteins matches their proposed interactions with host proteins. These include the localisation of Nsp13 to the centrosome, Orf3a to late endosomes and Orf9b to mitochondria.

Conclusions and Significance

This library should facilitate further cellular investigations, notably by imaging techniques.
Health‐related quality of life in hypothyroidism—A population‐based study, the WHO MONICA Project
Authors: Ellegård Lotta , Krantz Emily , Trimpou Penelope , Landin‐Wilhelmsen Kerstin
Published: March 2021

Objective

To explore health‐related quality of life (HRQoL) among subjects with hypothyroidism compared to subjects without hypothyroidism in the general population. HRQoL is important in clinical practice. Hypothyroidism is prevalent, mainly found in women, and increasing with age.

Design

Cohort study of random population sample.

Patients

Women and men, n = 414 (39–78 years) from the WHO MONICA project, Gothenburg, Sweden, participated. Hypothyroidism was defined as subjects having levothyroxine supplementation or serum thyroid‐stimulating hormone (S‐TSH) >4.2 mU/L.

Measurements

Health‐related quality of life was measured with Psychological General Well‐Being Index (PGWB), Nottingham Health Profile (NHP), Short Form 36 Health Survey (SF‐36) and a single item self‐rated health scale (0–100), and stress was rated 1–6. The results were adjusted for age, sex and comorbidity using analysis of covariance (ANCOVA).

Results

Hypothyroidism was found in 70 subjects (17%). They scored worse HRQoL than controls regarding Sleep (p < .001), Social isolation (p = .01) and Total NHP (p < .05), and had more medication in general 2.7 ± 2.5 vs. 1.8 ± 2.1, p < .05. Subjects with levothyroxine (n = 40) showed similar results as the total hypothyroid group. Subjects unaware of their newly detected elevated STSH (n = 30) showed lower HRQoL in Sleep (p < .01) and Pain (p < .05) in NHP. HRQoL was similar in subjects with and without positive thyroperoxidase antibodies (TPO‐Ab) either in those with hypothyroidism (44% TPO‐Ab) or controls (9% TPO‐Ab).

Conclusion

Men and women with hypothyroidism in the general population reported having more issues with Sleep and Social isolation than those without hypothyroidism irrespective of TPO‐Ab. Scores were similar in all of the other HRQoL domains measuredAQ5.
All type II classic MADS‐box genes in the lycophyte Selaginella moellendorffii are broadly yet discretely expressed in vegetative and reproductive tissues
Authors: Ambrose Barbara A. , Smalls Tynisha L. , Zumajo‐Cardona Cecilia
Published: March 2021

The MADS‐box genes constitute a large transcription factor family that appear to have evolved by duplication and diversification of function. Two types of MADS‐box genes are distinguished throughout eukaryotes, types I and II. Type II classic MADS‐box genes, also known as MIKC‐type, are key developmental regulators in flowering plants and are particularly well‐studied for their role in floral organ specification. However, very little is known about the role that these genes might play outside of the flowering plants. We investigated the evolution of type II classic MADS‐box genes across land plants by performing a maximum likelihood analysis with a particular focus on lycophytes. Here, we present the expression patterns of all three type II classic MADS‐box homologs throughout plant development in the lycophyte Selaginella moellendorffii: SmMADS1, SmMADS3, and SmMADS6. We used scanning electron microscopy and histological analyses to define stages of sporangia development in S. moellendorffii. We performed phylogenetic analyses of this gene lineage across land plants and found that lycophyte sequences appeared before the multiple duplication events that gave rise to the major MADS‐box gene lineages in seed plants. Our expression analyses by in situ hybridization show that all type II classic MADS‐box genes in S. moellendorffii have broad but distinct patterns of expression in vegetative and reproductive tissues, where SmMADS1 and SmMADS6 only differ during late sporangia development. The broad expression during S. moellendorffii development suggests that MADS‐box genes have undergone neofunctionalization and subfunctionalization after duplication events in seed plants.
Glial expression of DmMANF is required for the regulation of activity, sleep and circadian rhythms in the visual system of Drosophila melanogaster
Authors: Walkowicz Lucyna , Krzeptowski Wojciech , Krzeptowska Ewelina , Warzecha Karolina , Sałek Joanna , Górska‐Andrzejak Jolanta , Pyza Elżbieta
Published: March 2021

DmMANF, Drosophila melanogaster mesencephalic astrocyte‐derived neurotrophic factor (DmMANF) is an evolutionarily conserved orthologue of mammalian MANF. This neurotrophic factor exerts many functions in the Drosophila brain, particularly those dependent on glial cells. As we found in our earlier study, downregulation of DmMANF in glia induces degeneration of glial cells in the first optic neuropil (lamina) where DmMANF abundance is especially high. In the present study, we observed that changes in the level of DmMANF in two types of glia, astrocyte‐like glia (AlGl) and ensheathing glia (EnGl), affect activity and sleep of flies. Interestingly, a proper level of DmMANF in AlGl seems to be important in guiding processes of pigment dispersing factor (PDF)‐expressing clock neurons. This is supported by our finding that DmMANF overexpression in AlGl leads to structural changes in the architecture of the PDF‐positive arborization in the brain. Finally, we detected that DmMANF also affects rhythms in glia themselves, as circadian oscillations in expression of the catalytic α subunit of the sodium pump in the lamina epithelial glia were abolished after DmMANF silencing. DmMANF expressed in AlGl and EnGl seems to affect the activity of neurons leading to changes in behaviour.
Comparative study of blood pressure and echocardiographic values of male cynomolgus macaques (Macaca fascicularis)
Authors: Orlov Sergey V. , Panchenko Andrey V. , Beresneva Olga N. , Karal‐ogly Dzhina D. , Kucher Anatoly G. , Ivanova Galina T. , Parastaeva Marina M. , Smirnov Alexey V. , Kayukov Ivan G. , Kulikov Aleksander N.
Published: March 2021

Background

Primates represent a unique object for biomedical research, in particular in the field of physiology and pathology of the cardiovascular system. Echocardiography is the most important non‐invasive method for the intravital study of the heart structure and function, intracardiac and systemic haemodynamics. The available data on reference values of echocardiographic parameters in primates are limited.

Methods

We determined and described 29 structural and functional parameters in echocardiographic examination using B‐mode (two‐dimensional scanning), M‐mode (one‐dimensional scanning) and in various Doppler modes together with blood pressure in 17 male cynomolgus macaques with an average age of 5.7 ± 0.6 years. We compared available literature data on reference values of echocardiography in this species.

Results and conclusions

Echocardiographic values in cynomolgus macaques depend on age, sex composition and the anaesthesia method. There is lack of presentation in the published studies of complete list of parameters that can be obtained by echocardiographic examination.
Controlling monopoly power in a double‐auction market experiment
Authors: Attanasi Giuseppe , Boun My Kene , Guido Andrea , Lefebvre Mathieu
Published: March 2021

There is robust evidence in the experimental economics literature showing that monopoly power is affected by trading institutions. In this paper, we study whether trading institutions themselves can shape agents' market behavior through the formation of anchors. We recreate experimentally five different double‐auction market structures (perfect competition, perfect competition with quotas, cartel on price, cartel on price with quotas, and monopoly) in a within‐subject design, varying the order of markets implementation. We investigate whether monopoly power endures the formation of price anchors emerged in previously implemented market structures. Results from our classroom experiments suggest that double‐auction trading institutions succeed in preventing monopolists from exploiting their market power. Furthermore, the formation of price anchors in previously implemented markets negatively impacts on monopolists' power in later market structures.
Attitudes toward pharmacy‐based HCV/HIV testing among people who use drugs in rural Kentucky
Authors: Duong Michelle , Delcher Chris , Freeman Patricia R. , Young April M. , Cooper Hannah L.F.
Published: March 2021

Purpose

Rural areas of the United States have experienced outbreaks of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections among people who use drugs (PWUD). Pharmacy‐based interventions may play a crucial role in prevention and entry into care, especially when traditional health care access is limited. The willingness of rural PWUD to use pharmacies for HIV/HCV‐related services remains unknown. The purpose of this study was to describe the factors associated with the perceived likelihood of participating in free pharmacy‐based HIV and HCV testing among PWUD living in rural Kentucky.

Methods

Baseline data from the CARE2HOPE study in five Appalachian counties in eastern Kentucky were used. Participants were recruited using respondent‐driven sampling and completed interviewer‐administered surveys. Guided by the Andersen and Newman Framework of Health Services Utilization, we examined distributions and correlates of items regarding willingness to participate in free pharmacy‐based HIV/HCV testing using logistic regression. Analyses included individuals who reported being HIV (N = 304) or HCV (N = 185) negative.

Findings

Seventy‐five percent of PWUD reported being “very likely” to participate in free pharmacy‐based HIV testing and 80% for HCV testing. Two factors were associated with being less willing to participate in free HIV testing: PWUD who previously tested for HIV (OR: 0.47, CI: 0.25–0.88) and PWUD who obtained a high school diploma or equivalent compared to those who completed less (OR: 0.50, CI: 0.26–0.99).

Conclusion

Free pharmacy‐based HIV and HCV testing was invariably acceptable among most of the rural PWUD in our sample, suggesting that pharmacies might be acceptable testing venues for this population.
The active repertoire of Escherichia coli peptidoglycan amidases varies with physiochemical environment
Authors: Mueller Elizabeth A. , Iken Abbygail G. , Ali Öztürk Mehmet , Winkle Matthias , Schmitz Mirko , Vollmer Waldemar , Di Ventura Barbara , Levin Petra Anne
Published: March 2021

Nearly all bacteria are encased in peptidoglycan, an extracytoplasmic matrix of polysaccharide strands crosslinked through short peptide stems. In the Gram‐negative model organism Escherichia coli, more than 40 synthases and autolysins coordinate the growth and division of the peptidoglycan sacculus in the periplasm. The precise contribution of many of these enzymes to peptidoglycan metabolism remains unclear due to significant apparent redundancy, particularly among the autolysins. E. coli produces three major LytC‐type‐N‐acetylmuramoyl‐L‐alanine amidases, which share a role in separating the newly formed daughter cells during cytokinesis. Here, we reveal two of the three amidases that exhibit growth medium‐dependent changes in activity. Specifically, we report acidic growth conditions stimulate AmiB—and to a lesser extent, AmiC—amidase activity. Combining genetic, biochemical, and computational analyses, we demonstrate that low pH‐dependent stimulation of AmiB is mediated through the periplasmic amidase activators NlpD, EnvC, and ActS (formerly known as YgeR). Although NlpD and EnvC promote amidase activity across pH environments, ActS preferentially stimulates AmiB activity in acidic conditions. Altogether, our findings support partially overlapping roles for E. coli amidases and their regulators in cell separation and illuminate the physiochemical environment as an important mediator of cell wall enzyme activity.
Contrasting effects of mammal grazing on foliar fungal diseases: patterns and potential mechanisms
Authors: Liu Mu , Mipam Tserang Donko , Wang Xingxing , Zhang Peng , Lin Ziyuan , Liu Xiang
Published: March 2021

Plant pathogens and their hosts often coexist with mammal grazers. However, the direction and strength of grazing effects on foliar fungal diseases can be idiosyncratic, varying among host plant species and pathogen types.

We combined a 6 yr yak‐grazing experiment, a clipping experiment simulating different mammal consumption patterns (leaf damage vs whole‐leaf removal), and a meta‐analysis of 63 comparisons to evaluate how grazing impacts foliar fungal diseases across plant growth types (grass vs forb) and pathogen life histories (biotroph vs necrotroph).

In the yak‐grazing experiment, grazing had no significant effect on disease severity, and grasses experienced a higher disease severity than forbs; there was a significant interaction between pathogen type and grazing. In both the yak‐grazing experiment and meta‐analysis, grazing decreased biotrophic pathogens (mainly rusts and powdery mildew), but did not affect necrotrophic pathogens (mainly leaf spots). The clipping experiment suggested that grazers might promote infection by necrotrophic pathogens by producing wounds on leaves, but inhibit biotrophic pathogens via leaf removal.

In conclusion, our three‐part approach revealed that intrinsic properties of both plants and pathogens shape patterns of disease in natural ecosystems, greatly improving our ability to predict disease severity under mammal grazing.
Knowledge Representation and Conversion for Hybrid Expert Systems
Authors: Chambers Terrence L. , Parkinson Alan R.
Published: March 2021

Many different knowledge representations, such as rules and frames, have been proposed for use with engineering expert systems. Every knowledge representation has certain inherent strengths and weaknesses. A knowledge engineer can exploit the advantages, and avoid the pitfalls, of different common knowledge representations if the knowledge can be mapped from one representation to another as needed. This paper derives the mappings between rules, logic diagrams, frames, decision tables and decision trees using the calculus of truth-functional logic. The logical mappings between these representations are illustrated through a simple example, the limitations of the technique are discussed, and the utility of the technique for the rapid-prototyping and validation of engineering expert systems is introduced.
Feature-Based Design Using NURBS Entities and Plex Grammar
Authors: Guan Xiaogang , Theodoracatos Vassilios E.
Published: March 2021

A new feature-based design synthesis methodology is described. Features of various levels of complexity are created and classified according to their attributes. Each feature is represented as a single internal NURBS surface. A hierarchical structure of features with corresponding parameters is maintained to enhance the design efficiency. Plex grammar is used as a structure relationship descriptor to facilitate product concept analysis and geometric synthesis. Two product design examples are presented to illustrate the concept analysis and geometric synthesis process.
Genetic Operators for Catalog Design
Authors: Carlson Susan E. , Pegg Todd A.
Published: March 2021

Catalog design is the process of forming functional systems by assembling selected components from manufacturers’ catalogs. Generally, the engineer performs this design process in two steps: the selection of a basic system configuration, and the subsequent selection of specific components for that configuration. A genetic algorithm approach to catalog design will allow the integration of these two steps. This paper focuses on the four components of a genetic algorithm that must be developed for application to the catalog design problem. These operators include: a genetic representation of the design that includes its component parts and their connectivity, an initialization process for generating an initial set of designs, and a method for the exchange of the designs’ genetic information.
Analytical Solid Modeling Using Dual Kriging
Authors: Limaiem Anis , ElMaraghy Hoda A.
Published: March 2021

This paper presents a new method for representing analytical or parametric solids based on dual kriging. Complex solids may be represented with a single model without any limitation on the number of data points. The equations of the parametric model are derived in a simple and novel way by considering the combination of three interpolation profiles.

Dual kriging was successfully used for curve/surface modeling. It is a general method which incorporates several interpolation techniques in a single formulation, such as piecewise interpolation, cubic splines and Bezier curves/surfaces and solids. We will show that B-splines and NURBS are special cases of dual kriging. The model generated passes through all data points, and elementary shapes such as conics, cylinders are represented exactly. In addition, derivatives and linear constraints may be incorporated in the kriging model as well as uncertainties on data points.

Many applications, common to analytical solid modeling are possible, such as solid mesh generation in finite elements analysis, mass property calculations, composite material modeling and computer animation.
Optimal Layout of Shell Stiffeners With Frequency Design Considerations
Authors: Fu Yong , Gea Hae Chang
Published: March 2021

In this paper, a new method to design the layout of shell stiffeners is introduced. This new approach has been derived from a two-phase spherical micro-inclusions model and resulted in very simple closed-form expressions for the effective material properties. The “relaxed” topology optimization problem can then be solved by general mathematical programming tools. It is very common to experience the eigenvalue switchover when solving topology optimization problems with frequency design considerations. An incremental objective function formulation with two strategies were studied to reduce the oscillation of optimization solutions. Design Examples are presented and compared.
An Approach to Assembly Planning for Complex Products
Authors: Mukhanov Igor A.
Published: March 2021

We have developed a novel, efficient approach for assembly planning for complex products. This approach allows us to reflect the required information for assembly planning efficiently. Our approach has also been successfully used for the mathematical presentation of technological knowledge. An algorithm for the automatic generation of feasible assembly sequences for a given product has been developed. Within the assembly process-planning, feasible sequences are determined depending on the sequential assembly stages of the product. This approach permits the use of different criteria for the selection of a rational assembly plan, and it also allows for the influence of technological system elements (equipment, tools and periphery) on the given part of the product during a interval of the operation. We have successfully applied our approach for assembly process-planning of a complex product, a worm gear box. It has allowed us to reduce computation time greatly and to arrive at the optimal solution to real automated assembly.
The Efficient Optimization of the Linear Variance Function
Authors: Webb Sean , Parkinson Alan
Published: March 2021

In this paper we discuss the properties and optimization of the linear variance function. The linear variance function is a measure of the how variation in variables and parameters is transmitted to design functions. By minimizing this function, it is possible to develop robust designs that are more tolerant of variation. We discuss general mathematical properties of this function as well as properties of the variance of quadratic functions. We show how these properties can be used to more efficiently optimize the variance function, and report test results on seven problems. An example problem of a fluid flow check valve is presented showing how robustness can be achieved by minimizing the linear variance function.
Robust Design of Square-to-Box Rolling of Steel Rods
Authors: Yoshimura Koji , Shivpuri Rajiv , Ishii Kosuke
Published: March 2021

This study seeks a robust design of square-to-box rolling that leads to minimum variation in the geometric profile of rolled workpieces. Variations considered are the workpiece geometry, the roll diameter, and roll gap. The paper focuses on the variation of the workpiece width. The key is to define parameters that correctly reflect the physical characteristics of shape rolling. The study applies the Taguchi method to finite element simulation of rolling process using seven design and process parameters. Sensitivity analysis and comparison with empirical knowledge lead to design guidelines that reduce lateral spread variation in the square-to-box roll pass process.
A Framework for Component Layout and Geometry Design of Mechanical Systems: Configuration Network and its Viewing Control
Authors: Fujita Kikuo , Akagi Shinsuke
Published: March 2021

A Framework of computational design method and model is proposed for layout and geometry design of complicated mechanical systems, which is named “configuration network and its viewing control”. In the method, a design object is represented with a set of declarative relationships among various elements of a system, that is, configurations, which is gradually extended from schematic structure to exact layout and geometry through design process. Since a whole of such configurations forms a too complicated network to compute all together, how to view subparts is controlled based on levels of granularity and width of scope range. Such a configuration network is made to grow and refined through embodying geometry and layout corresponding to a focused subpart with a numerical optimization procedure. The framework has also an ability to flexibly integrate with engineering analysis. Moreover, a design system is implemented with an object-oriented programming technique, and it is applied to a design problem of air conditioner units in order to show the validity and effectiveness of the framework.
Parametric Continuity and Smooth Motion Interpolation
Authors: Srinivasan Lakshmi N. , Ge Q. J.
Published: March 2021

This paper deals with the design of a second derivative continuous (C2) motion that interpolates through a given set of configurations of an object. It derives conditions for blending two motion segments with C2 continuity and develops an algorithm for constructing a C2 composite Bézier type motion that has similarities to Beta-splines in the field of Computer Aided Geometric Design. A criteria for evaluating the smoothness of motion is established and is used to synthesize “globally smooth” motions. The results have applications in trajectory generation in robotics, mechanical systems animation and CAD/CAM.
Application of Bond Graphs in Rectilinear Modelling of Lumped Parameter Torsional Vibratory Systems
Authors: Abhary Kazem
Published: March 2021

Solution of complex lumped parameter torsional vibratory systems via the Holzer’s method and the Transfer Matrix method is not only lengthy and cumbersome, but the presence of damping prohibits the application of the former and exceedingly prolongs the application of the latter. In this paper, the problem has been approached through establishing the rectilinear model of the torsional system and bond graphs have been used as a medium to transform the torsional system into its rectilinear model. The model has been proven to follow a simple pattern and to be very rapidly constructible, irrespective of the complexity of the system.
On the Design of Spatial 4C Mechanisms for Rigid-Body Guidance Through 4 Positions
Authors: Larochelle Pierre M.
Published: March 2021

This paper presents a procedure for determining the fixed and moving congruences associated with four finitely separated spatial positions. Furthermore, a methodology is derived for selecting the lines from the congruences which define the joint axes of a 4C mechanism. The result is a design procedure for performing the kinematic dimensional synthesis of spatial 4C mechanisms for four position rigid body guidance.

Associated with four finitely separated positions in space are a fixed and a moving congruence. These congruences are a two dimensional set of lines, where each line defines the axis of a cylindrical joint that guides a body through the four prescribed positions. In order to uniquely determine a 4C mechanism from the congruences four free parameters must be specified. We present procedures for determining these free design parameters which result in mechanisms with joint axes that are nearest to some desired location. Moreover, included is a detailed numerical example illustrating the design process.
A Complex Number Approach to the Generation of the Cubic of Stationary Curvature
Authors: Johnson L. G. , Chase T. R.
Published: March 2021

A complex number approach to generating the cubic of stationary curvature (CSC) has been developed. The approach provides a closed form solution for generating points on the curve. The new approach eliminates the need for considering the Euler-Savary equation and centrode curvature as intermediate steps for obtaining points on the curve. Furthermore, the method guarantees that the points will be generated in their natural sequence and it simultaneously produces points on the centerpoint and circlepoint curves. The method can be applied to analyze an existing linkage or to synthesize a linkage to produce a coupler curve with specified stationary curvature at one position. Two analysis and one synthesis examples are provided.
A Real Time Solution to the Forward Kinematic Problem of a General Spherical Three-Degree-of-Freedom Parallel Manipulator
Authors: Boudreau Roger
Published: March 2021

In this paper, a real time solution to the forward kinematic problem of a general spherical three-degree-of-freedom parallel manipulator is presented using polynomial learning networks. These networks learn the forward kinematic problem based on a database of input-output examples. After the learning process has been achieved, the networks exhibit very little error when presented with inputs which were not part of the learning database. The computation time required to compute the forward kinematics is very small since the networks consist only of additions and multiplications.
Probabilistic Optimum Design of Compact Spur Gear Sets
Authors: Onwubiko Chinyere , Onyebueke Landon , Chen Feng C.
Published: March 2021

Several methods have been proposed in the past for optimum design of spur gears. These methods have utilized deterministic design optimization techniques to obtain what could be considered satisfactory design parameters. At least two problems arise with the results of the deterministic approach; the inability to deal with uncertainties in material properties and over conservative design. On the other hand, probabilistic analysis methodology seeks to account for the uncertainties in material properties, loading conditions and disparate failure models.

This paper discusses the application of probabilistic design methodology to the design of compact gear set. This is done by minimizing the gear center distance while constrained by the allowable surface pressure and bending stress. A comparison of the results of compact gear design using both deterministic and probabilistic methodologies is presented. The results indicate that deterministic method though satisfactory does not provide the designer enough information to make vast design decisions. The deterministic method provides only one value of the center distance while the probabilistic method provides the designer a range of choices. In fact, a designer is provided a wide range of design options depending on a desired level of reliability.
A Design Process Model That Unifies General Design Theory and Empirical Findings
Authors: Tomiyama Tetsuo
Published: March 2021

This paper proposes a new design process model that unifies theoretical results of General Design Theory (GDT) and empirical findings obtained from design experiments. It first reviews the design process models that were developed within theoretical work on GDT. Then, we describe experimental work on design based on protocol analysis, which resulted in a cognitive design process model from which further a computable design process model was derived. While these experimental results are supposed to support the theoretical conclusions obtained from GDT, we could also find out incompatibilities. We then propose a new design process model, called the refinement design process model, that can unify both theoretical results of GDT and experimental finding obtained from design experiments. The refinement model has better agreements with experimental findings and suggests various issues as a guiding principle to develop a future, advanced CAD system that helps a designer to focus on functional information. We propose and illustrate the concepts of such an advanced CAD system equipped with intensive design knowledge, called a computational framework for knowledge intensive engineering.
The Virtual Corporation: Simulating Real World Collaborative Design in a University Setting
Authors: Shah Jami J. , Sadowsky John S. , Macia Narcico F. , Woodfill Marvin C. , Wilson A. Fritz
Published: March 2021

A unique experiment is in progress for teaching design and manufacturing across the curriculum. Funded by the ARPA-Technology Reinvestment Program, and monitored by NSF, an organization called The Virtual Corporation was created to simulate inter-disciplinary product development in a large manufacturing company geared towards consumer products. Students registered in senior project classes in several engineering and business departments became the virtual employees of the company participating in design, manufacturing, and marketing in this simulated industrial setting. The product chosen was a robot for outdoor applications: autonomous, self-navigated, all-terrain, electric vehicle. This paper examines the methodology used, the educational goals achieved, and the lessons learnt from this one year experiment. Sufficient information is provided to enable duplicating this experiment elsewhere.
Protocol Analysis As a Research Technique for Analysing Design Activity
Authors: Dorst Kees , Cross Nigel
Published: March 2021

This paper offers a review of protocol analysis as a research technique for the investigation of design activity. It draws particularly on the results of a special international research workshop on protocol analysis of design activity, held in Delft, The Netherlands, in September 1994. The paper identifies major themes and issues in the use of protocol analysis arising from the workshop.
A Taxonomy of Decomposition Strategies Based on Structures, Behaviors, and Goals
Authors: Koopman Philip J.
Published: March 2021

Designs are often decomposed into subdesigns in a divide-and-conquer approach to dealing with complexity. A wide variety of strategies are in common use for accomplishing decomposition. This paper describes a taxonomy of decomposition strategies based on the design attributes of structures, behaviors, and goals as an aid to understanding when each different strategy may be appropriate. The taxonomy is descriptive rather than prescriptive; it concentrates on providing a common ground for representing both business-driven and technically-driven design decisions. An example is presented that suggests hierarchically layering diverse decomposition strategies can accommodate diverse designs and design processes.
A Design Environment for the Design of Micromachines
Authors: Huber Ralf , Grabowski Hans , Kiriyama Takashi , Yoneda Sigeru , Johnson Aylmer , Burgess Stuart
Published: March 2021

Micromachine technology has developed in recent years significantly and become an outstanding research field with remarkable results. In the past, several new products resulted, mainly related with sensors, actuators, and medical apparatus. The characteristics of micromachines are given by the interaction of miniaturised mechanical and electronic components, which are manufactured by methods originally developed for semiconductor production. These characteristics of micromachines are taken as occasion to investigate the possibilities of supporting the micromachine design process with knowledge based systems.

After a short introduction into knowledge based design systems and design methodologies, a case study on the micromachine design is presented. We will mainly examine the conceptual design stage based on the methodological design. From the case study, specific requirements for a design environment to support the micromachine design process are derived. These requirements are compared with the capabilities offered by today’s concepts for advanced design systems such as SYSFUND. Then, the necessary enhancement for SYSFUND that was found in the process of knowledge representation is described. Finally an extended concept for a micromachine design environment is discussed.
Understanding Emotion in Sound
Authors: Fukuda Shuichi , Matsuura Yoshifusa
Published: March 2021

The conventional sound recognition pursues meaning of a sound by analytical approach. But a human can recognize the emotional feelings of a speaker no matter what language he or she may use. There seems to be 2 kinds of such expressions. One is truly emotional at heart and another is to convey how he or she feels as a message. This work is aimed at understanding such messages of the emotional feelings of a speaker. Our preliminary work demonstrated that anger can be extracted from sound and characterized by noting the pitch frequency and the amplitude variation using cepstrum method.
Design Projects in a Mechanical Engineering Technology Curriculum
Authors: Jordan R. L. Alan
Published: March 2021

Design oriented “capstone” courses for senior students have enjoyed renewed popularity in recent years. However, incorporating design projects as part of lower level laboratory courses is not as widely practiced. This paper discusses the authors’ experience using design projects in four freshman/sophomore level mechanical engineering technology courses. In a mechanics of materials course, the students have been required to design a structure for an overhead granary, and a device to upright a large electrical transformer. In a fluid power course, students have been required to size and select components and create a schematic for a small machine. In a machine elements course, students have designed a commercial lawn mower and a ribbon printing machine.

Students in a production drawing class have designed and produced a set of working drawings for a stamping die, and have worked with a machine elements class as the documentation personnel on a concurrent engineering project. The projects all require problem definition, data research and collection, analysis of the required components, minimum sizing verses commercially available parts, and a schematic or full set of drawings. The desired outcomes are an increased level of interest, involvement, and to help the students make the transition between theory and practice.

Graduates of technology programs are involved in design after either an associate degree or a bachelors degree. These graduates will either assist engineers in the design process; or, be responsible for their own designs. The technologist must understand how the theory is applied to the solution of design problems. Design projects are utilized as a means of applying the theory learned in the courses and exposing the students to real life problem solving.

This paper will discuss some of the above named projects; how they are presented, how the students are involved, and the results. Some of the lessons learned will be presented. Reports are a major part of all the design projects. This paper will discuss how progress and final reports are utilized in these projects.
Virtual Reality System for the Evaluation of Complex Mechanical Systems
Authors: Bahr B. , Li G.
Published: March 2021

Industrial applications include problems where a particularly complex motion of the mechanical system needs to be designed, analyzed and verified. Computer simulation is one of the chief means to support these goals. This paper presents a virtual reality based simulation system for design, evaluation, and verification of the complex motion of mechanical systems. The realistic visualization and immersion of the system enables an engineer to evaluate the behavior of an existing mechanical system in an intuitive and natural-like way. It is also useful in the design and development of new mechanical systems since potential mistakes can be easily found in virtual environments before actual production.
Distributed-Parameter Design of Virtual Source Thermal Processing Methods
Authors: Doumanidis Charalabos , Fourligkas Nikolaos
Published: March 2021

In thermal manufacturing methods, visualization of the thermally generated distributions of material structure and properties in the products forms the basis for the development of a methodology for off-line design of the process conditions in virtual-source thermal techniques. These are implemented by timesharing a single heat source, scanning the external surface of the processed part to generate a flexible heat input distribution, and thus a specified temperature field yielding the desired thermal quality of the product. A numerical simulation of generic thermal processing is developed, integrating a solid conduction description to a flow model in molten regions. This computational model is validated by a comparative thermal study and is used for the design of the virtual source power and trajectory in rapid prototyping of laminated objects with specified geometric tolerances. Virtual-source processing based on real-time control with infrared thermal feedback is currently simulated for other thermal manufacturing processes.
Tree Search Based Algorithms for Tolerance and Process Selections
Authors: Qu G.
Published: March 2021

This paper describes a tree search based method to select tolerance values and processes for mechanical assemblies. Design constraint is a set of interrelated tolerance loops. The problem is to decide what tolerance, or equivalently, which manufacturing process, is to be allocated to each feature so as to minimize the cost of assembly within assembly tolerance constraints. With the properties of tolerance stackups, the global constraints are decomposed into a set of local constraints. Progressive application of the set of local constraints with sorting will dramatically prune the search tree and control its growth in both depth and width. Comparing to the zero-one for tolerance selection, these special purpose algorithms greatly reduce the search space and more efficient.
Virtual Prototyping of Die Design: Part One — Theory and Formulation
Authors: Wuerger David , Gadh Rajit
Published: March 2021

An important step in the design of dies for near-net-shape manufacturing processes is the determination of the die-open direction. The current research provides a computer-based approach to automatically determine the set of possible die-open directions for a given part. Computer-synthesized die design is often referred to as “Virtual Prototyping”. It has been determined in this research that certain features, called concavity features on a part, restrict the directions along which the die for a part may open, and are therefore used to determine the set of all possible die-open directions for a given part. Once the possible die-open directions are determined, a designer or a keyboard input system may decide which of these directions are usable.
Existence, Uniqueness and Asymptotic Behaviour for a Non-Linear Beam Equation
Authors: Boertjens G. Judith , van Horssen Wim T.
Published: March 2021

The use of perturbation methods for fourth order PDE’s has not yet been examined extensively. Usually approximating power series are applied, which are truncated to one or two modes. Very little — or nothing — is said about the relation between this approximation and the exact solution. In this paper initial boundary value problems for the following equation will be discussed:

w t t + w x x x x + ϵ ( u ( π , t ) − u ( 0 , t ) + ∫ 0 π w x 2 d x ) w x x = ϵ g ( x , t , w , w t ) .

This equation can be regarded as a model describing wind-induced oscillations of flexible structures like elastic beams, where the small term on the right hand side of the equation represents the windforce acting on the structure. Existence and uniqueness for solutions of these problems will be discussed, as well as finding approximations using a multiple time-scale method. Finally the asymptotic validity of these approximations will be considered.
Non-Linear Effects in Transient Dynamic Analysis of Flexible Multibody Systems
Authors: Pascal Madeleine
Published: March 2021

Some open questions arising in the dynamical formulation of systems of hinge-connected flexible bodies are discussed. The first one deals with the choice of the “floating reference frame” associated to a body under-going large rigid body motions but small elastic deformations. The second one is concerned by the so-called geometric stiffening (or centrifugal stiffening) effects. It is shown that in the most cases, these effects have to be taken into account only for slender bodies like beams or plates when they are subjected to axial or inplane forces.

The last problem is concerned by the eventual appearance of higher order terms in the kinetic energy of the system for large rates and large accelerations.
An Analytical Study of Stability of Periodic Systems by Poincaré Mappings
Authors: Guttalu Ramesh S. , Flashner Henryk
Published: March 2021

The Poincaré map (point mapping) analysis approach is used to investigate the stability of multivariable periodic dynamical systems. The approach presented here is based on a procedure to obtain an analytical expression for the period-to-period mapping description of system’s dynamics. It also allows to find analytical dependence of point mapping on system’s parameters. Analytical stability and bifurcation condition are then determined and expressed as functional relations between various system parameters. The approach is applied to investigate the parametric stability of flap motion of a rotor. It is shown that the proposed approach provides very accurate results when compared with direct numerical results which are assumed to be an “exact solution” for the purpose of this study. It is also demonstrated that the point mapping method yields more accurate results than the widely used classical perturbation analysis. To emphasize the applicability of the method for studying higher order systems, bifurcation and stability analysis of a two degree-of-freedom cantilever beam subjected to harmonic base motion is performed. The results of our analysis exhibit an excellent agreement with the “exact” (numerical integration) solution. The ability to perform analytical stability studies of systems with multiple degrees-of-freedom is an important feature of the proposed approach since most existing analysis methods are applicable to single degree-of-freedom systems. Extension of these methods to higher dimensional systems is not straightforward, and is usually very cumbersome.
Micro-Chaotic Behavior of Digitally Controlled Machines
Authors: Enikov Eniko , Stépán Gábor
Published: March 2021

The desired stationary motions of machines are often unstable. Human operator or computer control may be needed to stabilize these machines. An important common feature of both analog and digital controllers, is the time delay which is introduced into the system. Even when these delayed systems should be stable, the experiments show small stochastic oscillations around the desired motion. In case of the stabilization of an inverted pendulum, the analysis of the equation of motion shows that chaotic vibrations occur around the equilibrium even when stochastic effects related to human control are not present. In advanced design work of digitally controlled machines, it is vital to know the characteristics of this chaotic behavior. The estimation of the distribution of vibration amplitudes and the frequency range should be available at the design stage. This initiates the analysis of the so-called micro-chaos or μ-chaos.
Vibration, Buckling and Dynamic Stability of a Non-Uniform Cantilever Plate With Thermal Gradient Resting on a Pasternak Foundation
Authors: Takahashi Kazuo , Furutani Hisaaki
Published: March 2021

The dynamic stability of a non-uniform rectangular cantilever plate on a Pasternak foundation under the action of a pulsating inplane load is reported in this paper. The small deflection theory of the thin plate is used Hamilton’s principle is used to derive the time variables while the dynamic stability is solved by the harmonic balance method.

Natural frequencies and buckling properties are presented at first. Then, regions of instability which contain simple parametric resonances and combination resonances are discussed for various parameters of a Pasternak foundation, non-uniform cross section and thermal gradient.