Bibhas Chandra Giri and Sushil Kumar Dey
The purpose of this study is to investigate the impact of greening and promotional effort dependent stochastic market demand on the remanufacturer's and the collector's profits…
Abstract
Purpose
The purpose of this study is to investigate the impact of greening and promotional effort dependent stochastic market demand on the remanufacturer's and the collector's profits when the quality of used products for remanufacturing is uncertain in a reverse supply chain.
Design/methodology/approach
The proposed model is developed to obtain optimal profits for the remanufacturer, the collector and the whole supply chain. Both the centralized and decentralized scenarios are considered. To motivate the collector through profit enhancement, the remanufacturer designs a cost-sharing contract. Through numerical examples and sensitivity analysis, the consequences of greenness and promotional effort on optimal profits are investigated.
Findings
The results show that the remanufacturer gets benefited from greening and promotional effort enhancement. However, a higher value of minimum acceptable quality level decreases the profits of the manufacturer and the collector. A cost-sharing contract coordinates the supply chain and improves the remanufacturer's and the collector's profits. Besides green innovation, remanufacturing mitigates the harmful effects of waste in the environment.
Originality/value
Two different viewpoints of remanufacturing are considered here – environmental sustainability and economic sustainability. This paper considers a reverse supply chain with a remanufacturer who remanufactures the used products collected by the collector. The quality of used products is uncertain, and customer demand is stochastic, green and promotional effort sensitive. These two types of uncertainty with green and promotional effort sensitive customer demand differs the current paper from the existing literature.
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Yongjiang Xue, Wei Wang and Qingzeng Song
The primary objective of this study is to tackle the enduring challenge of preserving feature integrity during the manipulation of geometric data in computer graphics. Our work…
Abstract
Purpose
The primary objective of this study is to tackle the enduring challenge of preserving feature integrity during the manipulation of geometric data in computer graphics. Our work aims to introduce and validate a variational sparse diffusion model that enhances the capability to maintain the definition of sharp features within meshes throughout complex processing tasks such as segmentation and repair.
Design/methodology/approach
We developed a variational sparse diffusion model that integrates a high-order L1 regularization framework with Dirichlet boundary constraints, specifically designed to preserve edge definition. This model employs an innovative vertex updating strategy that optimizes the quality of mesh repairs. We leverage the augmented Lagrangian method to address the computational challenges inherent in this approach, enabling effective management of the trade-off between diffusion strength and feature preservation. Our methodology involves a detailed analysis of segmentation and repair processes, focusing on maintaining the acuity of features on triangulated surfaces.
Findings
Our findings indicate that the proposed variational sparse diffusion model significantly outperforms traditional smooth diffusion methods in preserving sharp features during mesh processing. The model ensures the delineation of clear boundaries in mesh segmentation and achieves high-fidelity restoration of deteriorated meshes in repair tasks. The innovative vertex updating strategy within the model contributes to enhanced mesh quality post-repair. Empirical evaluations demonstrate that our approach maintains the integrity of original, sharp features more effectively, especially in complex geometries with intricate detail.
Originality/value
The originality of this research lies in the novel application of a high-order L1 regularization framework to the field of mesh processing, a method not conventionally applied in this context. The value of our work is in providing a robust solution to the problem of feature degradation during the mesh manipulation process. Our model’s unique vertex updating strategy and the use of the augmented Lagrangian method for optimization are distinctive contributions that enhance the state-of-the-art in geometry processing. The empirical success of our model in preserving features during mesh segmentation and repair presents an advancement in computer graphics, offering practical benefits to both academic research and industry applications.
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Huiming Yang, Xia Yang and Yuqi Huang
The aim of this study is to establish the nonlinear dynamics equations of roller bearings with surface faults on outer raceway, inner raceway and rolling elements to analyze the…
Abstract
Purpose
The aim of this study is to establish the nonlinear dynamics equations of roller bearings with surface faults on outer raceway, inner raceway and rolling elements to analyze the dynamic characteristics of the double row self-aligning roller bearings, and provided theoretical basis for bearing fault diagnosis and life prediction.
Design/methodology/approach
First, based on the momentum theorem, the formulas for quantitative calculation of impact load were established, when roller was in contact with the fault of the inner or outer raceway. Then, the fault position piecewise functions and the load-carrying zone piecewise functions were established. Based on these, the nonlinear dynamic equations of double row self-aligning roller bearings are established, and Matlab is used to simulate the faulty bearings at different positions, sizes and rotational speeds. Finally, the vibration test of the fault bearings are completed, and the correctness of the nonlinear dynamic equations of the rolling bearing are verified.
Findings
The simulation and test results show that: the impact load increased with the increasing rotate speed and fault size, and the larger the fault size, the longer the impact load existed and the shorter vice versa.
Originality/value
The nonlinear dynamic equation of double row self-aligning roller bearings is established, which provides a theoretical basis for bearing faults diagnosis and fatigue life prediction.
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Jiaxing Wu, Wang Renxin, Xiangkai Zhang, Haoxuan Li, Guochang Liu, Xuejing Dong, Wendong Zhang and Guojun Zhang
This study aims to design a small-size conformable flexible micro-electro-mechanical system (MEMS) vector hydrophone to meet the miniaturization requirements of unmanned…
Abstract
Purpose
This study aims to design a small-size conformable flexible micro-electro-mechanical system (MEMS) vector hydrophone to meet the miniaturization requirements of unmanned underwater vehicle.
Design/methodology/approach
The cilia receive the acoustic signal to oscillate to cause changes in the stress on the beam, which in turn causes changes in the piezoresistive resistance on the beam, and changes in the resistance cause changes in the output voltage.
Findings
The results show that the flexible hydrophone in the paper has a sensitivity of −182 dB@1 kHz (re 1V/µPa) at 1 Pa sound pressure, can detect low-frequency hydroacoustic signals from 20 to 550 Hz and has good spatial directivity, and the flexible substrate permits the hydrophone to realize bending deformation, which can be well attached to the surface of the object.
Originality/value
In this study, a finite element simulation model of the hydrophone microstructure is constructed and its performance is verified by simulation. The success rate of the proposed MEMS transfer process is as high as 94%, and the prepared piezoresistors exhibit excellent resistance characteristics and high consistency. These results provide innovative ideas to enhance the performance and stability and achieve miniaturization of hydrophones.
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This chapter explores the perspectives of rural librarians about the information behaviors of children with special needs (CSN) and services available for the disenfranchised…
Abstract
Purpose
This chapter explores the perspectives of rural librarians about the information behaviors of children with special needs (CSN) and services available for the disenfranchised population in the Southern and Central Appalachian (SCA) region.
Methodology/approach
Qualitative feedback is collected from 31 SCA rural librarians via phone interviews and a web-based survey about: (1) The most important information needs/wants of the CSN in the SCA rural libraries; (2) The most important information resources and services that the CSN seek/use in the SCA rural libraries; (3) Extent of perceived need for effective library services for the CSN in rural areas; (4) Ways that the SCA rural libraries can improve to better serve the CSN in their local communities.
Findings
Content analysis of the data generated quantitative representation of response counts for specific themes that resulted in practical user-centered suggestions for positive change in delivering effective library services for the CSN in the SCA region.
Originality/value
Research significance lies in its first-time effort to understand the information needs and information uses of the CSN in the SCA rural library environments from the perspective of a rural librarian immersed in an American society that perceives a parochial regional work setting. This research presents data that challenges notions stereotyping and marginalizing of the “South” in its documentation of positive and meaningful efforts that rural librarians suggest should be made to improve the conditions experienced by the CSN in this region.
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C.M. Lawrence Wu and M.L. Chau
This paper presents a reliability assessment of adhesive joints using chip‐on‐glass (COG) technology which was conducted by testing samples at various aging temperatures and at…
Abstract
This paper presents a reliability assessment of adhesive joints using chip‐on‐glass (COG) technology which was conducted by testing samples at various aging temperatures and at high humidity.The range of aging temperatures took into account the glass transition temperature (Tg) of the adhesive films. The effects of high temperature and high humidity on the bond strength of flip‐chip‐on‐glass joints were evaluated by shear testing as well as by microstructural examination.It was found that aging generally caused a decrease in shear strength while the aging temperature was below the glass transition temperature of ACF. When the aging temperature was slightly above the Tg of the ACF, a significant decrease in shear strength was observed. Moreover, results from scanning electronic microscopy revealed the presence of some voids near the component bumps, resulting in high stresses at the high aging temperature. DSC results showed that the ACF was not fully cured, allowing moisture absorption more seriously than a fully cured ACF, leading to joint degradation.
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Viscosity is an important basic physical property of liquid solders. However, because of the very complex nonlinear relationship between the viscosity of the liquid ternary…
Abstract
Purpose
Viscosity is an important basic physical property of liquid solders. However, because of the very complex nonlinear relationship between the viscosity of the liquid ternary Sn-based lead-free solder and its determinants, a theoretical model for the viscosity of the liquid Sn-based solder alloy has not been proposed. This paper aims to address the viscosity issues that must be considered when developing new lead-free solders.
Design/methodology/approach
A BP neural network model was established to predict the viscosity of the liquid alloy and the predicted values were compared with the corresponding experimental data in the literature data. At the same time, the BP neural network model is compared with the existing theoretical model. In addition, a mathematical model for estimating the melt viscosity of ternary tin-based lead-free solders was constructed using a polynomial fitting method.
Findings
A reasonable BP neural network model was established to predict the melt viscosity of ternary tin-based lead-free solders. The viscosity prediction of the BP neural network agrees well with the experimental results. Compared to the Seetharaman and the Moelwyn–Hughes models, the BP neural network model can predict the viscosity of liquid alloys without the need to calculate the relevant thermodynamic parameters. In addition, a simple equation for estimating the melt viscosity of a ternary tin-based lead-free solder has been proposed.
Originality/value
The study identified nine factors that affect the melt viscosity of ternary tin-based lead-free solders and used these factors as input parameters for BP neural network models. The BP neural network model is more convenient because it does not require the calculation of relevant thermodynamic parameters. In addition, a mathematical model for estimating the viscosity of a ternary Sn-based lead-free solder alloy has been proposed. The overall research shows that the BP neural network model can be well applied to the theoretical study of the viscosity of liquid solder alloys. Using a constructed BP neural network to predict the viscosity of a lead-free solder melt helps to study the liquid physical properties of lead-free solders that are widely used in electronic information.
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Yu‐Cheng Lee, Hsiu‐Yuan Hu, Tieh‐Min Yen and Chih‐Hung Tsai
The purpose of this study was to examine overall customer satisfaction associated with medical service quality in Taiwan by integrated Kano’s model and customer satisfaction index…
Abstract
The purpose of this study was to examine overall customer satisfaction associated with medical service quality in Taiwan by integrated Kano’s model and customer satisfaction index model. Another purpose was to confirmed nonlinear and asymmetric relationship of Customer Satisfaction and Quality Performance by the research outcome. By analyzing 1,100 patients or their family members, this study used the structural equation model (SEM) with AMOS software for data analysis. The results show that must‐be attributes, one‐dimensional attributes and attractive attributes had a direct effect on overall customer satisfaction, Surprisingly, overall customer satisfaction had positively influenced customer loyalty customer satisfaction had negatively influenced customer complaints. The study also found that customer complaints have direct effect on customer loyalty. Importantly, the study found out the must‐be attributes, the attractive attributes and one‐dimensional attributes increased, the level of overall customer satisfaction also increased. The customer satisfaction positively influences customer loyalty in medical service quality in Taiwan. The findings might reveal new insights for researchers dealing with quality of medical service and for hospital managers who devote resources exclusively to achieving highest possible levels of patient satisfaction.
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This research aims to study the stencil printing process of the quad flat package (QFP) component with a pin pitch of 0.4 mm. After the optimization of the printing process, the…
Abstract
Purpose
This research aims to study the stencil printing process of the quad flat package (QFP) component with a pin pitch of 0.4 mm. After the optimization of the printing process, the desired inspection specification is determined to reduce the expected total process loss.
Design/methodology/approach
Static Taguchi parametric design is applied while considering the noise factors possibly affecting the printing quality in the production environment. The Taguchi quality loss function model is then proposed to evaluate the two types of inspection strategies.
Findings
The optimal parameter-level treatment for the solder paste printing process includes a squeegee pressure of 11 kg, a stencil snap-off of 0.14 mm, a cleaning frequency of the stencil once per printing and using an air gun after stencil wiping. The optimal upper and lower specification limits are 119.8 µm and 110.3 µm, respectively.
Originality/value
Noise factors in the production environment are considered to determine the optimal printing process. For specific components, the specification is established as a basis for subsequent processes or reworks.
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Abstract
Purpose
The interfacial structure is vitally important for achieving a good joint reliability during service. The purpose of this paper is to systematically explore the effects of Zn addition into the Sn-3.5Ag eutectic solder on the formation of intermetallic compound (IMC) layer at the interface between Sn-3.5Ag-xZn (x = 0, 0.9 and 3) solders and Cu pad.
Design/methodology/approach
To obtain useful information on the formation of interfacial structure and to determine an effective way to avoid the formation of brittle joints, a series of Sn-Ag lead-free solders with different Zn contents were prepared and soldered. To investigate the IMC layers between Sn-3.5Ag-xZn (x = 0, 0.9 and 3) lead-free solders and the Cu pads, three specimens of the Sn-3.5Ag-xZn/Cu were soldered at 250°C for one min.
Findings
It is found that the addition of Zn in the Sn-3.5Ag eutectic solder can prompt the formation of Cu5Zn8 IMCs, and restrain the formation of the Cu6Sn5 IMCs. Moreover, the addition of Zn in the Sn-3.5Ag eutectic solder will reduce the solubility of Cu in the liquid solder, which accelerates the growth of the formed IMCs. Consequently, the thickness of IMC layer increases with increasing the content of Zn.
Originality/value
This paper usefully demonstrates how the addition of Zn favoured the formation of the Cu5Zn8 phase and restrained the formation of the Cu6Sn5 phase. Moreover, the addition of Zn in the Sn-Ag eutectic solder would reduce the solubility of Cu in the liquid solder, which accelerates the growth of the formed IMCs. Consequently, the thickness of the IMC layer increased with increasing concentration of Zn.