bluuebunny/crossref_metadata_2025 huggingface dataset:
A genetically-informed study disentangling the relationships between tobacco smoking, cannabis use, alcohol consumption, substance use disorders and respiratory infections, including COVID-19
Authors: Rosoff Daniel B. , Yoo Joyce , Lohoff Falk W.
Published: February 2021

Background

Observational studies suggest smoking, cannabis use, alcohol consumption, cannabis use, and substance use disorders (SUDs) may play a role in the susceptibility for respiratory infections and disease, including coronavirus 2019 (COVID-2019). However, causal inference is challenging due to comorbid substance use.

Methods

Using genome-wide association study data of European ancestry (data from >1.7 million individuals), we performed single-variable and multivariable Mendelian randomization to evaluate relationships between smoking, cannabis use, alcohol consumption, SUDs, and respiratory infections.

Results

Genetically predicted lifetime smoking was found to be associated with increased risk for hospitalized COVID-19 (odds ratio (OR)=4.039, 95% CI 2.335-6.985,P-value=5.93×10−7) and very severe hospitalized COVID-19 (OR=3.091, 95% CI, 1.883-5.092,P-value=8.40×10−6). Genetically predicted lifetime smoking was also associated with increased risk pneumoniae (OR=1.589, 95% CI, 1.214-2.078,P-value=7.33×10−4), lower respiratory infections (OR=2.303, 95% CI, 1.713-3.097,P-value=3.40×10−8), and several others. Genetically predicted cannabis use disorder (CUD) was associated with increased bronchitis risk (OR=1.078, 95% CI, 1.020-1.128,P-value=0.007).

Conclusions

We provide strong genetic evidence showing smoking increases the risk for respiratory infections and diseases even after accounting for other substance use and abuse. Additionally, we provide find CUD may increase the risk for bronchitis, which taken together, may guide future research SUDs and respiratory outcomes.
The effect of TTM-based nutrition education on decisional balance, self-efficacy and processes of change for fat intake
Authors: Gordali Maedeh , Bazhan Marjan , Ghaffari Mohtasham , Omidvar Nasrin , Rashidkhani Bahram
Published: February 2021

Purpose

The purpose of this study is to determine how transtheoretical model (TTM) constructions change through nutrition education for fat intake modification among overweight and obese women living in Shazand city, Iran.

Design/methodology/approach

A semi-experimental design with intervention and control groups (50 women in each group) was performed. TTM constructions for dietary fat intake were measured through a questionnaire in four phases: before the intervention, immediately, one month and six months after the intervention. Participants in two groups were classified into inactive and active subgroups, based on their determined stage of change. Then in the intervention group, each subgroup received a separate education program of five or eight sessions for the active and inactive subgroups, respectively.

Findings

The intervention resulted in significant progress in participants' stage of change compared to the control group (p = 0.002). Also, it resulted in an increase in the self-efficacy and decisional balance scores in both of the intervention subgroups, with these effects being more pronounced in the inactive subgroup, and these significant differences, compared to the control group, remained in the third and fourth phases. The intervention also positively impacted the behavioral processes, but this effect was not so long-lasting and decreased after six months.

Originality/value

The results indicated the intervention effectiveness and the necessity of planning educational interventions to change fat consumption behavior. This study provides further insight into effective and sustainable nutrition education strategies based on behavioral change stages rather than traditional approaches. These methods should be used to design group interventions to change individuals' health behavior in future works.
Technology-dependent pedagogical process redesign: leveraging lean methods
Authors: Deranek Kimberly , Kramer Steven , Siegel Sharon
Published: February 2021

Purpose

This research compared the efficacy of process outcomes leveraging lean methods versus traditional pedagogy applied to dental education dependent on emerging technology. The pedagogical objective was to improve system efficiency without compromising traditional outcomes of effectiveness (quality).

Design/methodology/approach

The research team tested the efficacy of a lean A3 framework to identify, remove waste and redesign a technology-dependent simulation laboratory course (CAD/CAM/IR Restorative Dentistry). Students were also sensitized to time-in-chair to introduce a stronger patient focus. Baseline data collected from a control group were statistically compared to the research group's data after the course redesign. In addition, course time allocations were measured and then compared.

Findings

The results showed the interventions significantly reduced procedure cycle times without compromising quality. Additionally, the course was more efficiently conducted as measured by course time allocations.

Practical implications

This research demonstrated that the use of the A3 framework enhanced learning through process documentation, reengineering and systems optimization resolving issues of inefficiency associated with the CAD/CAM/IR pedagogy. This work is significant because it demonstrates the practice of using lean interventions to redesign and improve a technology-based healthcare course to maximize benefits.

Originality/value

This research is the first to examine how to leverage lean methods in a healthcare simulation laboratory, dependent on innovative technology, to educate and train future practitioners. This research applied statistical rigor in a controlled experiment to maximize its applicability and generalizability.
The impact of retailers' indoor environmental quality on consumer purchase decision
Authors: Dang Van Thac , Nguyen Ninh , Wang Jianming
Published: February 2021

Purpose

A review of 67 articles in the indoor environmental quality (IEQ) literature published from 2010 to 2020 reveals that none of prior studies have determined the IEQ of physical retailers and its impact on consumers. To fill such a gap, this study investigates the influence of physical retailers' IEQ on consumer purchase intention. The mediating roles of hedonic experience and perceived brand value (PBV) in this relationship are also determined. Furthermore, the moderating effect of perceived service quality (PSQ) on the link between physical retailers' IEQ and PBV is clarified in this study.

Design/methodology/approach

This study uses structural equation modeling (SEM) to analyze a sample data of 996 consumers in China.

Findings

Results show that physical retailers' IEQ has a positive impact on consumer purchase intention. Hedonic experience mediates the link between IEQ and purchase intention. PBV also mediates the relationship between IEQ and purchase intention and that between hedonic experience and purchase intention. In addition, PSQ moderates the relationship between IEQ and PBV.

Originality/value

To the best of the authors’ knowledge, this study is the first to determine the impact of IEQ on consumers in the physical retailer context. Specifically, this study enriches our knowledge about the relationship between physical retailers' IEQ and consumer purchase intention with the mediating and moderating mechanisms of hedonic experience, PBV and PSQ. The findings fill the research gaps in the IEQ literature that has ignored the impact of IEQ on consumers' perception and behavioral intention in the physical retailer context. Furthermore, this research provides evidence for retailer managers to understand and improve physical stores' IEQ.
Financial sector development and life insurance inclusion in India: an ARDL bounds testing approach
Authors: Mathew Biju , Sivaraman Sunitha
Published: February 2021

Purpose

This paper analyses the relationship between financial sector development (FSD) and life insurance inclusion in India during the period from 1971–1972 to 2016–2017. The study analyses the effect of financial deepening on life insurance inclusion in India.

Design/methodology/approach

The study employs augmented Dickey–Fuller (ADF) unit roots test to check the stationarity properties of the time series data. It estimates a life insurance inclusion model using the auto-regressive distributed lag model (ARDL) bounds testing approach to cointegration.

Findings

The study finds evidence of a cointegrating relationship between financial deepening and life insurance inclusion in India. A significant error correction coefficient indicates automatic adjustments to short-run disequilibrium, reinforcing the cointegrating relationship between financial sector and life insurance inclusion.

Research limitations/implications

A major limitation of the study is that it excludes the first-time sum assured (FSA) contributed by the private sector life insurance companies due to lack of data availability.

Practical implications

The results of the study call for faster expansion of the financial sector and provision of a low interest rate regime in the Indian economy. The study invokes the need for sufficient training to the personnel in the banking and non-banking institutions to cater to the complex needs of life insurance buyers.

Originality/value

The paper estimates the link between FSD and life insurance inclusion and introduces a new measure of life insurance demand, the life insurance inclusion, measured using the FSA.
Effect of shot peening on the wear behavior of Ti(C,N) coating on TA15 alloy prepared by double glow plasma carbonitriding
Authors: Xue Lin , Miao Qiang , Liang Wenping , Zhao Hui , Shi Weiwei , Zuo Shiwei , Ma Hanchun
Published: February 2021

Purpose

The purpose of this paper is to prepare Ti(C,N) coatings on TA15 treated and not treated by shot peening using double glow plasma alloying technique. The effect of shot peening on the wear behavior of Ti(C,N) coatings is discussed.

Design/methodology/approach

The Ti(C,N) coatings were prepared by double glow plasma alloying technique on two different TA15 substrate; one is shot peened and the other is not.

Findings

Ti(C,N) coating on SP-treated TA15 was thicker and denser, and the grain size was smaller compared with that on original TA15. Compared with the Ti(C,N) coating on original TA15, the wear resistance of that on SP-treated TA15 is improved. Ti(C,N) coating on SP-treated TA15 showed higher nanohardness and bearing capacity than that on original TA15.

Originality/value

For double glow plasma alloying technique, surface quality, surface activity and other factors will have influence on the thickness and density of the coating. The wear mechanisms of Ti(C,N) coating on original TA15 are serious abrasive wear and oxidation wear. However, the wear mechanism of Ti(C,N) coating on SP-treated TA15 is slightly oxidation wear.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0283/
Building trust in sharing economy platforms: trust antecedents and their configurations
Authors: Akhmedova Anna , Vila-Brunet Neus , Mas-Machuca Marta
Published: February 2021

Purpose

The sharing economy is the internet-enabled business model that has changed the way people travel, work and interact. Similar to other internet-enabled settings, trust is of paramount importance for the sharing economy as it leads to continued use and positive word-of-mouth. The main objectives of this research are twofold: (1) to identify the most relevant antecedents of trust in the sharing economy; and (2) to identify which combination of these antecedents allows repurchase intention and positive word-of-mouth to be achieved.

Design/methodology/approach

Through revision of trust theories and complementary frameworks, and an analysis of the sharing economy, the authors develop a model of trust for the sharing economy. The authors propose a model assuming that different types of trust will form a limited number of pathways valid for the creation of positive behavioural intentions. The authors use qualitative comparative analysis to empirically assess the proposed model on a sample of 235 sharing economy users.

Findings

The authors find two configurations that jointly suggest the key role of website quality and usability in generating consumer trust. The authors propose that, on the one hand, platforms might focus on creating value-added services and increasing the reliability of the platform brand. On the other hand, platforms can focus on creating good signalling mechanisms and educate their service providers towards reliable behaviour.

Originality/value

The authors build a conceptual model of trust in the sharing economy setting, that considers the feedback loops among the combination of several dimensions. The authors define specific strategies for platforms in the sharing economy that lead to repurchase intention and positive word-of-mouth.
Operational efficiency of tow trucks: a case based evidence from an Indian automobile manufacturer
Authors: Rose J. Sharon , Gopal PRC , M. Arputham Ramkumar
Published: February 2021

Purpose

The purpose of this paper is to examine and model the in-plant operational efficiency of tow trucks of an automobile manufacturing plant. Even though, tow trucks contribute toward the improvement of operational performance, little case-based evidence prevail in the literature. For this purpose, a case study has been conducted in an Indian automobile manufacturer to address the prevailing issues in material handling (MH).

Design/methodology/approach

Initially, this paper focuses on grouping of the sequence parts and finding the shortest path among the groups. To elucidate this, an analytical framework based on the distance and stuffing quantity is proposed. A fuzzy Dijkstra’s algorithm is used to solve the issues in grouping of the sequence parts and shortest path among the groups.

Findings

This study addressed the four aspects of MH: move cost, time, distance and material by integrating the function of grouping, finding the shortest path and communication with low cost devices. The result shows that logistics routes and activities should not be interrupted by any of the external factors. The availability of stock is a key performance variable to attain efficiency. In addition to this, effective communication between the truck operators and the production line managers is key performance indicator.

Originality/value

The paper helps the automobile practitioners on increasing the efficiency of tow truck by systemizing the routes. Logistics routes and activities should not be interrupted by any of the external factors. The availability of stock is a key performance variable to attain efficiency. In addition to this, effective communication between the truck operators and the line managers is key performance indicator.
Shadow prices for intangible resources
Authors: Shakina Elena , Naidenova Iuliia , Barajas Angel
Published: February 2021

Purpose

Focusing on managerial problems related to the measurement of intangibles, this paper develops and validates a hedonic-pricing methodology for the evaluation of the intangible resources of companies obtaining their shadow prices.

Design/methodology/approach

The paper adapts a hedonic-pricing methodology developed primarily for markets in real estate and secondhand cars to define how much intangibles may contribute to companies' market value. A certain calibration of the original tool has been developed to make this methodology appropriate for interpretation and practical use. The main advantage of this approach is that it allows for an evaluation of the shadow prices of intangible resources. These prices can be interpreted as the market value of the intangible resources which are not reflected on the balance sheet.

Findings

The results of this study demonstrate that hedonic pricing with a self-selection correction generates robust estimates. As one can see, the positive contribution of a high endowment of intangibles for all shadow prices is confirmed through estimations using two different techniques. Meanwhile, the negative effect of a low endowment is even more evident for the baseline model. This model shows consistent negative shadow prices for the majority of underinvested intangibles. Brands have the highest shadow prices in the introduced models; human capital, as measured by the qualification of top management and investments in employees, has likewise demonstrated high prices. However, most structural resources seem to be not reflected to a large degree in companies' market value.

Practical implications

This paper brings new opportunities to obtain the monetary value of intangible resources based on estimated market prices of a corporation's resource portfolio. These prices may be used for several purposes – for example, benchmarking for performance management, capital budgeting or knowledge-management practices. Moreover, by having methodological value, this study opens ways to evaluate any other intangibles which are not explicitly discussed in the empirical test of this particular study.

Originality/value

This study primarily contributes to the methodological advancement of evaluation of corporate intangible resources. It departs from the conventional hedonic-pricing mechanism to identify cogent estimates to intangibles in monetary terms. Importantly, this mechanism implies individual shadow prices for specific intangible resources which makes the contribution of this study unique for the existing literature, both within resource-based and value-based views.
The health halo of morality- and purity-signifying brand names
Authors: Amos Clinton , King Jesse , King Skyler
Published: February 2021

Purpose

Past research has demonstrated a health halo for food product labels (e.g. organic), resulting in inflated perceptions of a product’s healthfulness (e.g. low fat). While past studies have focused on labeling and related health claims, the health halo of brand names has scarcely been investigated. This study aims to address this gap by investigating the health halo of brand names featuring morality- and purity-signifiers.

Design/methodology/approach

The current research uses two experiments to examine the health halo of morality- and purity-signifying brand names on perceptions of nutritional and contaminant attributes. Mediation analysis is performed to investigate perceived naturalness as the mechanism for the brand name effects while moderated mediation analysis examines this mechanism across product types (healthy vs unhealthy).

Findings

The findings reveal that both the morality- and purity-signifying brand names produce a health halo on nutritional and contaminant attributes, regardless of product healthiness. Further, mediation and moderated mediation analysis provide evidence for perceived naturalness as the underlying mechanism driving these effects.

Social implications

This research highlights unwarranted consumer inferences made based upon food brand names and, thus has implications for consumers, public policy and marketing managers.

Originality/value

While much health halo research has focused on labeling, this research examines the health halo of two brand name types which symbolically convey either morality or purity. This research provides additional contributions by investigating perceived naturalness as the underlying mechanism for the effects and is one of the few studies to investigate the health halo for both healthy and unhealthy products.
Sales response to corporate social irresponsibility and the mitigating role of advertising
Authors: Sharpe Stacey , Hanson Nicole
Published: February 2021

Purpose

This study examines the relationship between corporate social irresponsibility (CSI) and firm-level sales and estimates the potentially mitigating role of advertising.

Design/methodology/approach

To test their hypotheses, the authors conduct an empirical investigation using a sample of 381 US firms engaging in socially irresponsible behavior.

Findings

The results of this investigation indicate that while sales are negatively impacted during the year of a CSI event, they generally recover in the year immediately following the event. In addition, advertising is shown to mitigate the negative impact of CSI on sales in both the event year and the year immediately following. The authors also consider whether differences exist between CSI firms with and without advertising. From this comparative analysis, it is observed that CSI firms which advertise tend to experience more severe declines in sales. Also, such firms tend to recover from the negative implications of CSI sooner.

Originality/value

This paper provides a novel and empirical approach to assessing the relationship between CSI events and firm-level sales while quantifying the mitigating effects of advertising. Furthermore, the unique contributions and practical findings of this research generate strong support for the significant role advertising can play in helping firms recover from CSI-based brand crisis events and help to establish a promising path for future research.
Numerical investigation of optimal wall materials for effective thermal performance in warm and hot climatic regions
Authors: Selvaraj Subhashini , Kesavaperumal Thirumaran
Published: February 2021

Purpose

Heat gain in buildings occurs due to heat transfer through the building fabric or envelope, especially the walls and roof. The purpose of this paper is to identify and recommend the suitable wall materials for better thermal performance in buildings in warm and hot climatic zones of India. As India lies between the tropic of cancer and the equator, the solar radiation from the sun falls more on the walls than the roofs of the buildings. Thus, it is imperative to protect the walls from heat gain to promote thermal comfort in naturally ventilated buildings and reduce the energy loads due to artificial cooling systems in air-conditioned buildings.

Design/methodology/approach

In this paper, an investigation of heat flow characteristics in steady-state and the transient state for five different uninsulated wall structures using computational fluid dynamics (CFD) software has been carried out. The climate conditions at Madurai, India have been considered for this study.

Findings

The findings of the study revealed that aerated autoclaved concrete (AAC) and hollow clay blocks (HCB) for external walls in naturally ventilated buildings in warm climatic regions could improve the building’s thermal performance index and reduce peak indoor operative temperature by about 6°C–7°C. The results of steady-state and transient state analysis were found to be in good agreement with the results of the reviewed literature.

Research limitations/implications

Over the past few decades, only very few architects and builders have been successful in influencing their clients to accept alternate materials such as AAC blocks, HCB, stabilized earth blocks, adobe blocks, fly-ash bricks as an alternate to conventional bricks in an attempt of highlighting their benefits, such as; materials that are easily available, more energy-efficient, can withstand the extreme weather conditions, promote thermal comfort and cost-effective. This paper provides strong evidence that AAC and HCB blocks are the most appropriate materials for improving the thermal performance of envelope walls in regions where the outdoor temperatures are above 40°C.

Originality/value

This paper has made an attempt to identify the appropriate wall materials for effective thermal performance in warm and hot climates. A comparative analysis between five different wall types under the existing solar conditions has been analyzed using CFD simulation study in steady-state and transient conditions under summer conditions and the appropriate wall materials have been suggested. There has been no attempt carried out so far to analyze the thermal performance of different walls using 24 h transient approach in CFD.
Photopatch testing in Chinese patients: A 5‐year experience
Authors: Shao Yixin , Hu Yue , Wang Duoqin , Zhu Yiqi , Shen Yanyun , Xu Jinhua , Tang Hui
Published: February 2021

Background

In 2015, a Chinese expert consensus on photopatch testing (PPT) was established, based on European consensus methodology.

Objectives

To update current information on the prevalence of photoallergic contact dermatitis (PACD) to 20 photoallergens and their clinical relevance in the Chinese context.

Methods

A retrospective analysis of 2372 patients who performed PPT in a tertiary referral center in China between 2015 and 2019 was completed.

A total of 1208 PACD reactions were observed in 897 (37.8%) patients, and 413 reactions were of current or past relevance.

Results

The proportion of reactions of current or past relevance was 34.2%. The most frequent photoallergens were chlorpromazine, thimerosal, potassium dichromate, and formaldehyde. The ultraviolet absorbers, benzophenone and Para‐aminobenzoic acid, showed opposite gender distribution to PACD. Twenty‐five patients (1.9%) developed PACD reactions to a newly added photoallergen preparation – fragrance mix I. Patients with chronic actinic dermatitis, widespread exposed‐site or generalized dermatitis, and older age were more likely to have PACD.

Conclusions

This study is the first to profile PACD reactions with clinical relevance in China. The prevalence of PACD to culprit photoallergens was affected by regional peculiarities. Attention needs to be paid to the age, body‐site distribution, and known diagnoses of patients for the identification of PACD.
Psychiatric disorders in emerging adults with diabetes transitioning to adult care: A retrospective cohort study
Authors: Robinson Marie‐Eve , Simard Marc , Larocque Isabelle , Shah Jai , Rahme Elham , Nakhla Meranda
Published: February 2021

Aims

During transition from paediatric to adult diabetes care, adolescents with diabetes are at increased risk of psychiatric disorders compared with those without diabetes. Prolonged gaps between the last paediatric and first adult diabetes care visit are associated with higher perceived stress and lower life satisfaction. We assessed the effect of a gap (>180 days) in establishing adult diabetes care on the risk of psychiatric disorders and determined other risk factors associated with psychiatric disorders during the transfer to adult care.

Methods

Using provincial health administrative databases, we conducted a retrospective cohort study of individuals from Québec, Canada, diagnosed with diabetes between ages 1 and 15 years in 1997–2015. These individuals were followed from 6 months after their last paediatric visit until age 25 years. We used multivariable Cox proportional hazard models to determine the association of gap in care with psychiatric disorders risk.

Results

Among 1772 youth with diabetes, 740 (42%) had a gap in care. There was a non‐statistically significant association between gap in care and mood disorders diagnosed in the emergency department or hospital (hazard ratio [HR] 1.38, 95% confidence interval [CI]: [0.92, 2.07]). Older age at transfer, recent birth year and higher number of all‐cause emergency department visits in the year before transfer increased the risks of psychiatric disorders.

Conclusions

Prolonged gaps in care during transfer to adult care are common and may be associated with increased psychiatric disorder risk. Developmental factors associated with adolescence and emerging adulthood may further amplify this risk.
Supremacy and hegemony: a reply to Palmer and Martin
Authors: ALLAN JAMES , CAMPBELL DAVID
Published: February 2021

In a 2019 article in this journal, which drew on previous work, we argued by examination of a number of extremely important cases that the senior judiciary is in the process of attempting to create judicial supremacy in the UK. It is doing so, not by democratic debate, but by legal procedural innovation incomprehensible to the electorate. Invited by the journal to reply to a criticism of our argument by Dr Stephanie Palmer and Dr Stevie Martin, we have sought to defend our account of the undemocratic procedural novelty of those cases.
Writing a User Friendly Procedural Manual for ST/8 CNC Lathe
Authors: Hotchkiss Anthony , Geldard Bruce
Published: February 2021

The ability to work with something new is only as good as the instructions provided or the knowledge relayed by experience. This is certainly the case for a CNC lathe that was purchased and installed in 1994 at the State University College at Buffalo. After installation, it was not immediately possible to start the machine and perform machining operations without some difficulty. The ST/8 Rhino Robotics CNC lathe is a small unit that should allow practice in programming in a relatively safe environment, and should not take an exorbitant amount of time to accomplish any minor task. This paper describes a project that produced a user friendly manual that any student can follow and use successfully.
Buckling of Plates by Boundary Elements
Authors: Lin Jauhorng , Duffield Roger C. , Shih Hui-Ru
Published: February 2021

This investigation is concerned with the determination of a solution to the onset of instability of elastic plate subjected to non-uniform edge loads and/or displacements using boundary element method. In this study, the in-plane stress distribution was taken to be unknown due to non-uniform external in-plane boundary loading and/or displacements. The fundamental solution which is used to solve plate bending problems was used as the weighting function in the solution to the plate buckling problem. With this approach, the resulting integral equations still retained some domain integral terms which were then converted to boundary integral terms by means of the dual reciprocity method. With the introduction of proper shape functions, the boundary integral equations were transformed into a set of simultaneous algebraic equations expressed in a standard eigenvalue matrix format. A number of examples were studied to obtain the critical load factor and the critical buckling load. Results were then compared with analytical solutions and numerical results obtained by means of the finite element method, to illustrate the accuracy and applicability of the proposed solution procedures for solving plate buckling problems.
Structural Analysis by the Differential Quadrature Method Using Modified Weighting Matrices
Authors: Choi Siu-Tong , Chou Yu-Tuan
Published: February 2021

The differential quadrature method has lately been more and more often used for analysis of engineering problems as an alternative for the finite element method or finite difference method. In this paper, static, dynamic and buckling analyses of structural components are performed by the differential quadrature method. To improve the accuracy of this method, an approach is proposed for selecting the sampling points which include base points and conditional points. The base points are taken as the roots of the Legendre polynomials. Accuracy of the problems analyzed will be increased by using the base points. The conditional points are determined according to boundary conditions and specified conditions of external load. A modified algorithm is proposed for applying two or more boundary conditions in a sampling point at boundary of domain, such that the higher-order partial differential equation can be solved without adding new sampling points.

By applying this approach to variety problems, such as deflections of beam under nonuniformly distributed loading, vibration and buckling analyses of beam and plate, it is found that numerical results of the present approach are more accurate than those obtained by the equally-spaced differential quadrature method and is computationally efficient.
Parameter Identification of Hysteretic Structures
Authors: Zhang H. , Tuan G. , Foliente G. C. , Ma F.
Published: February 2021

This paper reports on the time-domain identification of parameters of a smooth hysteretic model proposed by Bouc and Wen. Two different identification methods, the Levenberg-Marquardt method and the simplex method, are employed to identify the hysteretic parameters.
Internet-Based Delivery of CAD/CAM Capability: An Industry Case Study
Authors: Szykman Simon , Sriram Ram D.
Published: February 2021

This paper presents a case study in the use of the Internet as a medium for exchange of information and delivery of computer-aided design and computer-aided manufacturing (CAD/CAM) capability. The case study describes a collaboration among researchers and staff at the National Institute of Standards and Technology (NIST), and Thar Designs, Inc., a small business in Pittsburgh, PA that designs and sells high-pressure fluid pumps. The objective of this case study is to identify the needs of small businesses in engineering industry in the area of Internet-based CAD/CAM services. The Internet-based interaction performed in this study encompassed various stages in an iterative product development process, consisting of design, data exchange, manufacturability analysis, and fabrication of a prototype.
Telepresence for Distributed Rapid Prototyping: A VRML Approach
Authors: Huegel J. , Ganter M. A. , Storti D. W.
Published: February 2021

In response to economic forces that continue to pressure designers/engineers to speed the product development process and decrease the time required to bring new products to market, designers/engineers are more frequently employing rapid prototyping to test design concepts and stimulate customer feedback in the earlier stages of design. Rapid prototyping (RP) is therefore becoming an integral part of the design and manufacturing process to which designers/engineers desire direct access on a regular basis. However, such access is not currently possible, since prototyping machines have not yet fulfilled the goal of becoming inexpensive and ubiquitous office equipment. This paper presents an extendable process that provides virtual access to manufacturing machines via the Internet. We chose two RP systems to demonstrate our technique. Our approach uses Virtual Reality Modeling Language (VRML) as a standard for transmitting the 3D graphical information necessary for a remote user to interact with a virtual representation of a real prototyping machine. The user thus achieves an effective telepresence in the distributed rapid prototyping environment. Following a brief discussion of related research and the essentials of VRML, we present examples describing the current state of telepresence achievable for two rapid prototyping systems.
Creating and Managing Virtual Menus in Immersive Environments
Authors: Jayaram Uma , Mathrubutham Narayanan , Jayaram Sankar
Published: February 2021

A 3D menu, also called a virtual menu, is now an accepted method of interaction between the user and the computer in an immersive environment. It adds functionality and allows interactions that are usually difficult to specify through direct interaction. We present the design and methodology of a support system for 3D menu creation and interaction in an immersive environment. Three kinds of virtual menus are supported — a paddle, a static billboard, and a dynamic billboard. These are distinguished by different spatial presentation and interaction paradigms in the virtual environment. The integration of the support system into an immersive environment is presented in the context of engineering applications research at Washington State University. Problems encountered and future planned enhancements are also examined. A clean separation between the virtual menu support system and the application in which the virtual menu will be created and displayed has been maintained.
Automatic Draw Direction Generation for Die Design
Authors: Vijay J. V. K. , Shrinivasa U. , Gurumoorthy B.
Published: February 2021

The concept of visibility maps was first used by Woo et al (Woo et al., 1994) to find the draw directions for a die. This paper describes an algorithm that extends this idea by handling free form surfaces, parts requiring multiple draw directions and parts with pockets that have a null visibility map. The algorithm also identifies the core and cavity portions of the die.
Computer-Aided Design for Product De- and Remanufacture
Authors: Harper Brian , Rosen David W.
Published: February 2021

Increasingly, designers are asked to consider additional types of requirements, including the environmental impact of their designs during the product’s lifetime and after its useful life. Two of these types of requirements are investigated in this paper. Demanufacturing is the process of dismantling a product and preparing for the disposal or recycling of components, modules, or materials. Product reuse retains a greater portion its value and often requires remanufacturing, the refurbishment of a product or product modules. Assessments of a product’s ease of de- and remanufacture are often desirable at various stages during the design process. In this paper, requirements for CAD representations to support de- and remanufacture assessments are identified. Information requirements are classified into categories according to the difficulty in extracting the information from assembly-based CAD representations. Information not obtainable from CAD representations is noted. Methods for querying CAD systems to extract significant amounts of this information are presented. These methods have been incorporated into the prototypical CAD system CODA. This work is applied to the design for de- and remanufacture of an automotive instrument cluster. It is shown that feasible disassembly sequences can be generated, ideal parts can be recognized, disassembly times can be reliably estimated, and input can be generated for spreadsheet-based assessment tools.
Experimental and Numerical Study of Blade Profiles for Axial Flow Fans
Authors: Henry Veronique
Published: February 2021

An experimental and numerical investigation is presented for blade profiles in axial flow fans. In order to improve the aerodynamic design of the blades, first numerical simulations with a two dimensional cascade oriented code have been performed in the rotor passage of a single-stage axial flow ventilation fan. The optimization design has been performed involving statistics. The influence of four design parameters have been investigated: rate of curvature, leading edge shape, chordwise location of the maximum camber and chordwise location of the maximum thickness. The new profile produced has been tested in wind-tunnel with a well-known C4 profile to validate the expected performance level. Next step has consisted in performing Navier-Stockes computations. Results demonstrate that the use of a coupled viscous-inviscid approach is appropriate for blade design and optimization. The Navier-Stockes code can be seen as a complementary tool as it leads to a complete description of the flow.
An Approach for Symbolic Design Optimization Based on Monotonicity Analysis and Groebner Bases Method
Authors: Li Li , Chen Yong
Published: February 2021

An approach for determining the symbolic expression of the optimum solution for the symbolic design optimization (the problem with symbolic coefficients) based on monotonicity analysis and Groebner bases method is presented in this paper. By this approach, the equivalent system of equality constraint equations for the subproblem derived from monotonicity analysis can be solved directly. Criteria for ordering the variables and terms of the equations are developed based on the features of the equations, thus the “triangularized” Groebner Bases for the subproblems, i.e. the symbolic expression of the optimum solution, can be generated rapidly An example is given demonstrating the strategy and efficiency of the approach.
Second-Order Design Sensitivity Analysis of Mechanical System Dynamics by a Mixed Direct Differentiation Adjoint Variable Method
Authors: Urruzola Javier , Jiménez José Manuel
Published: February 2021

This paper presents a new approach to second order sensitivity analysis of multibody dynamics. Adjoint variables together with direct differentiation are used to derive first- and second-order derivatives of measures of dynamic response with respect to design variables. It is shown that the proposed method can be compared advantageously to the fully adjoint variable method proposed by Haug in terms of simplicity and numerical cost. In order to validate the algorithm, a simple oscillator example proposed by Haug is solved analytically and by the mixed method, with identical results.
Including Life Cycle Considerations in the Design of an Electric Vehicle Space Frame
Authors: Ortega Roberto A. , Bras Bert
Published: February 2021

Today’s increasing demands placed on vehicles in terms of increased power, reduced emissions, maintenance and energy consumption, and end of life cycle issues related to recycling and disposal have made vehicle life cycle design a very important issue. However, life cycle issues are typically not concurrently addressed during the development stages. In this paper, our interest is in determining vehicle frame design specifications that include technical as well as environmental life cycle considerations. The design of an electric vehicle space frame is used for our study. Technical performance and environmental life cycle considerations are taken into account, represented by the travel distance between charges and an environmental life cycle assessment, respectively. These considerations are mapped into structural and safety issues, which represent the critical vehicle frame design constraints. In order to rapidly explore the design space and perform trade-off studies, response surface models are constructed and used to characterize the physical behavior of the space frame. The purpose of our research is to provide designers with a decision support tool that will enable them to efficiently and effectively include and investigate life cycle considerations early in the design process. This is our primary emphasis in this paper, not so on the results of our example problem, per se.
Robust Design of Product Families for Make-to-Order Systems
Authors: Hernandez Gabriel , Simpson Timothy W. , Allen Janet K. , Bascaran Eduardo , Avila Luis F. , Salinas Fabian
Published: February 2021

Although manufacturing plants dedicated to a single product exist, most plants today make multiple products. The pressure to compete via product variety and customization has served to increase the number of different products produced by a typical plant. The manufacturing systems of complex make-to-order families of products usually face problems associated with the high variability of processing times, supply deliveries and market demand. How can product design improve the performance of the manufacturing system of complex make-to-order products? In this paper we present a method, based on robust design principles and a multi-objective decision model embodied in the Robust Concept Exploration Method, to support concurrent decisions in the early stages of the design of make-to-order families of products. Emphasis is given to adopting standardization, modularity and robustness in product design as key principles to improve the performance of this kind of systems. The design of an absorber-evaporator module for a family of absorption chillers is used as an example to illustrate our approach.
Agent Support for Design of Aircraft Parts
Authors: Jha Krishna N. , Morris Andrea , Mytych Ed , Spering Judith
Published: February 2021

Designing aircraft parts requires extensive coordination among multiple distributed design groups. Achieving such a coordination is time-consuming and expensive, but the cost of ignoring or minimizing it is much higher in terms of delayed and inferior quality products. We have built a multi-agent-based system to provide the desired coordination among the design groups, the legacy applications, and other resources during the preliminary design (PD) process. A variety of agents are used to model the various design and control functionalities. The agent-representation includes a formal representation of the task-structures. A web-based user-interface provides high-level interface to the users. The agents collaborate to achieve the design goals.
Solving Topology Optimization Problems Using Wavelet Approximations
Authors: DeRose Giuseppe C. A. , Díaz Alejandro R.
Published: February 2021

A new method to solve topology optimization problems is discussed. This method is based on the use of a Wavelet-Galerkin scheme to solve the elasticity problem associated with each iteration of the topology optimization sequence. Typically, finite element methods are used for this analysis. However, as the mesh size grows, the computational requirements necessary to solve the finite element equations increase beyond the capacity of current desk top computers. This problem is inherent to finite element methods, as the condition number of finite element matrices increases with mesh size. Wavelet-Galerkin techniques are used to replace standard finite element methods in an attempt to alleviate this problem. Examples demonstrating the performance of the new methodology are presented.
Virtual Proving Ground Simulation for Vehicle Design
Authors: Haug Edward J. , Cremer James , Papelis Yiannis , Solis Dario , Ranganthan R.
Published: February 2021

Emerging ground vehicle driving simulation technologies and simulator capabilities are presented, which establish the foundation for a fundamentally new vehicle virtual proving ground suitable for vehicle system and subsystem design. Engineering level of fidelity modeling capabilities, previously used in Computer-Aided Engineering for vehicle design, are extended to real-time simulation with the driver-in-the-loop for highly realistic virtual proving ground simulation. Capabilities of the National Advanced Driving Simulator, being developed by the US Department of Transportation and The University of Iowa are presented, and advanced simulation technologies required for the envisioned virtual proving ground capability are summarized. This paper sets the stage for technical papers presented in a Special Session of the 1998 ASME Design Automation Conference on Virtual Proving Ground Simulation.
A New Method for Modeling of Cutting Tools Associated With Rolling Axodes
Authors: Oancea Nicolae , Oancea Victor G.
Published: February 2021

Most of the existing methods for determining the profiles of cutting tools that work by wrapping are based on the envelope theory which requires cumbersome analytical formulations associated with the solution of equations not always easy to resolve. This work presents a new alternative method for studying conjugated surfaces associated with rolling axodes. The original meshing surfaces are replaced by a family of curves of substitution which gives a simpler interpretation of the envelope theory. The meshing line and the contact points can be easily determined. An equidistant to the tool profile can be simply calculated which can be very useful in the case of machining with cylindrical abrasive disks. Several examples are shown for rack, shaper and rotational cutters.
Geometrical Reasoning for Glue Operation in Non-Manifold Modeling
Authors: Park Sangho
Published: February 2021

Euler and Boolean operations of non-manifold models provide a versatile environment for modeling domains. The implementation of these operations raises geometrical issues that need to be addressed to ensure the topological validity of the underlying model, and they use the glue operation which provides a basic method to modify the topology of non-manifold models when vertices, edges and faces are contacting each other.

Topological information such as adjacency relationships should be inferred when gluing non-manifold models. Two methods of reasoning can be employed to find the topological information : topological reasoning and geometrical reasoning. The topological method can infer the adjacency relationships by using stored topological information. On the other hand, the geometrical method can find topological ambiguities by considering the geometrical shape at the local area of gluing when the topological relations were not stored. This paper describes the geometrical reasoning method.