M.A. Jafari, W. Han, F. Mohammadi, A. Safari, S.C. Danforth and N. Langrana
In this article we present the system that we have developed at Rutgers University for the solid freeform fabrication of multiple ceramic actuators and sensors. With solid free…
Abstract
In this article we present the system that we have developed at Rutgers University for the solid freeform fabrication of multiple ceramic actuators and sensors. With solid free form fabrication, a part is built layer by layer, with each layer composed of roads of material forming the boundary and the interior of the layer. With our system, up to four different types of materials can be deposited in a given layer with any geometry. This system is intended for fabrication of functional parts; therefore the accuracy and precision of the fabrication process are of extreme importance.
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T.F. McNulty, F. Mohammadi, A. Bandyopadhyay, D.J. Shanefield, S.C. Danforth and A. Safari
A new family of thermoplastic binders has been developed for usage in fused deposition of ceramics (FDC). Mixtures were formulated consisting of a base binder, tackifier, wax, and…
Abstract
A new family of thermoplastic binders has been developed for usage in fused deposition of ceramics (FDC). Mixtures were formulated consisting of a base binder, tackifier, wax, and plasticizer. The resultant formulation was chosen based on mechanical, rheological, and thermal property requirements. A formulation consisting of 100 parts base binder (by weight), along with 20 parts tackifier, 15 parts wax, and five parts plasticizer exhibited an optimized compromise of mechanical, rheological, and thermal properties. This formulation was compounded with 55 vol. per cent lead zirconate titanate (PZT) powder, and extruded into filaments with a diameter of 1.75mm and a length of approximately 50 (+/‐10) cm. The resulting filaments were used to fabricate functional piezoelectric ceramic devices via FDC. The binder development process is described, along with the associated mechanical, rheological, and thermal property data.
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The purpose of this paper is to develop a dynamic compact thermal model (DCTM) of electronic packages. This model is a necessary tool for rapid thermal analysis of the systems…
Abstract
Purpose
The purpose of this paper is to develop a dynamic compact thermal model (DCTM) of electronic packages. This model is a necessary tool for rapid thermal analysis of the systems which we exposed to boundary condition variation and/or power switching mode such as mobile systems and battery powered systems.
Design/methodology/approach
The methodology of compact model generation used was based on generating the transient dynamic detailed finite element thermal model of a package, designing a resistor/capacitor network topology representative of the dynamic detailed model, calculating the resistors'/capacitors' value by optimization method and validation efforts. The method is demonstrated for a ball grid array (BGA) package, a commonly used modern electronic package.
Findings
Based on the obtained results, it can be concluded that the dynamic thermal behavior of a BGA package can be accurately described by a generated dynamic compact model in terms of predicted junction temperature response and heat flux of the desired locations of the package.
Originality/value
This model is capable of calculating the temperatures and heat fluxes at desired locations which can help the designer to perform the thermal analysis much faster and easier with the required accuracy.
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In recent years, the airline industry has been growing and transforming rapidly in the Asia-Pacific area. This study analyzes and benchmarks the comparative operational…
Abstract
In recent years, the airline industry has been growing and transforming rapidly in the Asia-Pacific area. This study analyzes and benchmarks the comparative operational efficiencies of the major Asian air carriers. Data envelopment analysis model and disaggregate output efficiency measures are used to evaluate the operational efficiencies of 31 Asian airlines from 2015 to 2019. The findings suggest that nonflag carriers, low-cost carriers, and high-income regions' carriers have significantly higher levels of efficiency than flag carriers, full-service carriers, and low-income regions' carriers in overall, revenue, and passenger traffic efficiencies. The efficiencies between alliance carriers and nonalliance carriers along with those of ASEAN and non-ASEAN carriers are not significantly different.
Saeed Hatefi Ardakani, Peyman Fatemi Dehaghani, Hesam Moslemzadeh and Soheil Mohammadi
The purpose is to analyze the mechanical behavior of the arterial wall in the degraded region of the arterial wall and to determine the stress distribution, as an important factor…
Abstract
Purpose
The purpose is to analyze the mechanical behavior of the arterial wall in the degraded region of the arterial wall and to determine the stress distribution, as an important factor for predicting the potential failure mechanisms in the wall. In fact, while the collagen fiber degradation process itself is not modeled, zones with reduced collagen fiber content (corresponding to the degradation process) are assumed. To do so, a local weakness in the media layer is considered by defining representative volume elements (RVEs) with different fiber collagen contents in the degraded area to investigate the mechanical response of the arterial wall.
Design/methodology/approach
A three-dimensional (3D) large strain hierarchical multiscale technique, based on the homogenization and genetic algorithm (GA), is utilized to numerically model collagen fiber degradation in a typical artery. Determination of material constants for the ground matrix and collagen fibers in the microscale level is performed by the GA. In order to investigate the mechanical degradation, two types of RVEs with different collagen contents in fibers are considered. Each RVE is divided into two parts of noncollagenous matrix and collagen fiber, and the part of collagen fiber is further divided into matrix and collagen fibrils.
Findings
The von Mises stress distributions on the inner and outer surfaces of the artery and the influence of collagen fiber degradation on thinning of the arterial wall in the degraded area are thoroughly studied. Comparing the maximum stress values on outer and inner surfaces in the degraded region shows that the inner surface is under higher stress states, which makes it more prone to failure. Furthermore, due to the weakness of the artery in the degraded area, it is concluded that the collagen fiber degradation considerably reduces the wall thickness in the degraded area, leading to an observable local inflation across the degraded artery.
Originality/value
Considering that little attention has been paid to multiscale numerical modeling of collagen fiber degradation, in this paper a 3D large strain hierarchical multiscale technique based on homogenization and GA methods is presented. Therefore, while the collagen fiber degradation process itself is not modeled in this study, zones with reduced collagen fiber content (corresponding to the degradation process) are assumed.
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Faezeh Mohammadi Tahroodi and Norsidah Ujang
Functioning as space connectors, path structures in urban parks may rarely present social interaction opportunities, although centralized activity spaces are available. This paper…
Abstract
Purpose
Functioning as space connectors, path structures in urban parks may rarely present social interaction opportunities, although centralized activity spaces are available. This paper investigated the interrelationships between the visual and physical accessibility attributes of path structure and their impacts on passive social interaction intensity across urban parks in Kuala Lumpur.
Design/methodology/approach
The concept of social interaction has been studied elsewhere in social cohesion, social affiliation and sense of communication. Still, it has not been studied in the context of urban park design. This study employed mixed methods using an adaptive and unique combination of qualitative and quantitative data collections to analyze urban parks with a bit of visual vegetation barrier. The experiential landscape method was applied to determine visual accessibility by interpreting experiential landscape maps. The space syntax method based on quantitative analysis is considered to measure physical accessibilities and vigorous activities along the designated paths by conducting integration analysis and gate observation. The data were crossed-analyzed using a Geographic Information System (GIS) classification technique, correlation analysis and Microsoft combo-charts to generate the relationship between patterns of activities and their accessibilities.
Findings
The results suggested that designated paths with higher accessibility attributes, impressively more elevated than other tracks, could influence the intensity of passive social interactions. The findings supported the understanding that activity nodes and active areas adjoining designated routes could make accessibility attribute areas more critical. These findings verify that visually enriching the spaces along the path structure toward activities is a pivotal contributor to urban planners and designers to enhance the paths’ local integration (LI) and visual accessibility to predict more passive eye contact among park visitors.
Research limitations/implications
The proposed interrelationship among variables in this study has limitations because of not considering other qualitative methods and techniques like cognitive maps and interview simultaneously. These techniques could discover why some paths generate more passive eye contact among park users (Mohammadi Tahroodi, 2018).
Practical implications
Kuala Lumpur Structure Plan 2020 emphasizes Kuala Lumpur’s unique image as a tropical garden city via preserving and developing the iconic historical urban parks in the city center (CHKL, 2004, pp. 3–3). The latest Draft Kuala Lumpur Structure Plan 2040 has outlined the strategy to achieve a conducive, good-quality neighborhood that encourages social interaction. The findings could assist urban planners and designers better public parks by considering accessibility and permeability aspects of design. This research endorses the appropriateness of interrelationship between accessibility attributes of path structure and social interaction in urban design research, which local urban designers have not fully considered until now. Evaluating the visual convenience of designated paths and assessing LI of the axial lines constructing each designated route of urban parks during the primary stage could enable urban designers to estimate to what extent the paths are accessible and respond to passive social interaction. Then they could enrich with salient landmarks, views and activity nodes to make them attractive. The considerable number of designated paths connections, specifically while they shape the sides of activity nodes, could increase the connectivity and integration of spaces within the parks. These patterns of positioning the activity nodes make the designated routes more legible and provide ease of movement. As a result, it will give urban park users more information about the activities. Allowing people to use the paths will increase people’s presence and, subsequently, passive social interaction. One way is to locate accessible lands that provide social activities at direct visual access paths within urban parks for legibility.
Social implications
The socially responsive urban design enhances the quality of life and provides life satisfaction, happiness and society’s overall health. Being in urban social parks in any passive and active situations has psychological benefits. It facilitates relief and rests from a stressful modern lifestyle that significantly impacts their mental health and well-being. The framework applied in this research integrates the social, spatial and physical aspects of parks design. With this regard, principles and indicators facilitate physically and socially attractive urban parks for Kuala Lumpur city center and applicable to similar contexts elsewhere.
Originality/value
The concept of social interaction has been studied elsewhere in social cohesion, social affiliation and sense of communication. Still, it has not been studied in the context of urban park design. This study employed mixed methods using an adaptive and unique combination of qualitative and quantitative data collections to analyze urban parks with a bit of visual vegetation barrier.
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HamidReza Khankeh, Mehrdad Farrokhi, Mohammad Saatchi, Mohammad Pourebrahimi, Juliet Roudini, Amin Rahmatali Khazaee, Mariye Jenabi Ghods, Elham Sepahvand, Maryam Ranjbar and Mohammadjavad Hosseinabadi-Farahani
This study aims to review the results of relevant studies to shed light on social trust-building in different contexts and the factors that affect it in disaster risk management.
Abstract
Purpose
This study aims to review the results of relevant studies to shed light on social trust-building in different contexts and the factors that affect it in disaster risk management.
Design/methodology/approach
This systematic review was conducted using the Preferred Reporting Items for Systematic reviews and Meta-Analyses model. The study keywords were searched for in PubMed, Scopus and Web of Science databases on August 2021. The inclusion criteria were English-written articles published in social trust and disaster relief efforts. Exclusion criteria were lack of access to the full text and article types such as nonoriginal articles.
Findings
Out of 1,359 articles found, 17 articles were included in the final analysis using four general categories: six articles on the role of local government in trust-building (local governments), five articles on the role of social media in trust-building (social media), four articles on the role of social capital in trust-building (social capital) and two articles on the importance of community participation in trust-building (community participation).
Originality/value
Understanding the role of social trust and the factors which influence it will help the development of community-based disaster risk management. Therefore, disaster management organizations and other relief agencies should take the findings of this study into account, as they can help guide policymaking and the adoption of strategies to improve public trust and participation in comprehensive disaster risk management. Further studies recommended understanding people’s experiences and perceptions of social trust, relief and disaster preparedness.
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Fatemeh Shekari, Fatemeh Azizi and Zohre Mohammadi
Considering the diversity of literary sites, various needs and motivations of literary visitors, and the limited research on literary tourists’ experiences, this study aims to…
Abstract
Purpose
Considering the diversity of literary sites, various needs and motivations of literary visitors, and the limited research on literary tourists’ experiences, this study aims to explore the literary gaze at Hafez Tomb in Shiraz, Iran. As the visitor gaze encompasses various dimensions of experience, this study connected the two notions to identify the components of the literary gaze and determine the attributes that best describe it.
Design/methodology/approach
Data sources include semi-structured interviews with visitors and user-generated content on Tripadvisor. The deductive thematic analysis and multiple correspondence analysis were used.
Findings
The findings revealed the multidimensionality of the literary gaze. The dominant factors that best describe the literary gaze at Hafez’s tomb were the sensory component of the experience, including “seeing”, “smelling”, “hearing”; affective including “anticipation”, “joy”, “trust”; cognitive including “perceiving”, “thinking”, “learning”; behavioural including “literary related”, “general”; and relationship including “tourist-companion”, “tourist-tourist”.
Practical implications
Understanding the literary gaze can assist site managers and destination marketers in designing the literary experience and developing promotional strategies that reflect the multifaceted nature of the literary experience. Tourism authorities should identify and shape tourists’ perceptions of literary sites to build the city’s image and brand as a literary city.
Originality/value
This paper used the orchestra model of experience to analyse the literary tourist’s gaze. This modification could explain that the literary gaze has multiple dimensions and studying all the dimensions gives the literary experience greater significance.
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The purpose of this paper is to enhance the line congestion and to minimize power loss. Transmission line congestion is considered the most acute trouble during the operation of…
Abstract
Purpose
The purpose of this paper is to enhance the line congestion and to minimize power loss. Transmission line congestion is considered the most acute trouble during the operation of the power system. Therefore, congestion management acts as an effective tool in using the available power without breaking the system hindrances or limitations.
Design/methodology/approach
Over the past few years, determining the optimal location and size of the devices have pinched a great deal of consideration. Numerous approaches have been established to mitigate the congestion rate, and this paper aims to enhance the line congestion and minimize power loss by determining the compensation rate and optimal location of a thyristor-switched capacitor (TCSC) using adaptive moth swarm optimization (AMSO) algorithm.
Findings
An AMSO algorithm uses the performances of moth flame and the chaotic local search-based shrinking scheme of the bacterial foraging optimization algorithm. The proposed AMSO approach is executed and discussed for the IEEE-30 bus system for determining the optimal location of single TCSC and dual TCSC.
Originality/value
In addition to this, the proposed algorithm is compared with various other existing approaches, and the results thus obtained provide better performances than other techniques.
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Jiang Wu, Xiaobo Wang, Xianghui Zhao, Chunbao Zhang and Bo Gao
The purpose of this paper is to explore an application of computer‐aided design and manufacture (CAD/CAM) to a process of electronically surveying a scanned dental cast as a prior…
Abstract
Purpose
The purpose of this paper is to explore an application of computer‐aided design and manufacture (CAD/CAM) to a process of electronically surveying a scanned dental cast as a prior stage to producing a sacrificial pattern for a removable partial denture (RPD) metal alloy framework.
Design/methodology/approach
With the introduction of laser scan technology and commercial reverse engineering software, a standard plaster maxillary dental cast with dentition defect was successfully scanned and created as a STL‐formatted digital cast. With the software, the unwanted undercuts were eliminated based on the desired path of insertion. Parts of the RPD framework were then successfully custom‐designed and combined as a whole.
Findings
A sacrificial pattern was produced by rapid prototyping (RP) method and finally casted with chromium cobalt alloy. With suitable finishing process, both the sacrificial pattern and the casted framework fitted the cast well.
Originality/value
The research indicated the feasibility of creating a library of RPD framework components. It is believed that, in the future, with the advance of the techniques, a totally new platform can be developed for the design and fabrication of custom‐fit RPD framework based on the CAD/CAM/RP system.