bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved proportional topology optimization algorithm for minimum volume problem with stress constraints
Authors: Cheng Wenming , Wang Hui , Zhang Min , Du Run
Published: June 2020

Purpose

The purpose of this paper is to propose an improved proportional topology optimization (IPTO) algorithm for tackling the stress-constrained minimum volume optimization problem, which can meet the requirements that are to get rid of the problems of numerical derivation and sensitivity calculation involved in the process of obtaining sensitivity information and overcome the drawbacks of the original proportional topology optimization (PTO) algorithm.

Design/methodology/approach

The IPTO algorithm is designed by using the new target material volume update scheme and the new density variable update scheme and by introducing the improved density filter (considering the weighting function based on the Gaussian distribution) and Heaviside-type projection operator on the basis of the PTO algorithm. The effectiveness of the IPTO algorithm is demonstrated by solving the stress-constrained minimum volume optimization problems for two numerical examples and being compared with the PTO algorithm.

Findings

The results of this paper show that the uses of the proposed strategies contribute to improving the optimized results and the performance (such as the ability to obtain accurate solutions, robustness and convergence speed) of the IPTO algorithm. Compared with the PTO algorithm, the IPTO algorithm has the advantages of fast convergence speed, enhancing the ability to obtain accurate solutions and improving the optimized results.

Originality/value

This paper achieved the author’s intended purpose and provided a new idea for solving the stress-constrained optimization problem under the premise of avoiding obtaining sensitivity information.
Help me, I can’t afford it! Antecedents and consequence of risky indebtedness behaviour
Authors: Abrantes-Braga Farah Diba M.A. , Veludo-de-Oliveira Tânia
Published: June 2020

Purpose

This study aims to develop and test a parsimonious theoretical model of risky indebtedness behaviour, a facet of over-indebtedness that refers to the behavioural tendency of often assuming hazardous debt levels.

Design/methodology/approach

The authors administered an online survey to credit card owners (n= 1,288) in an emerging economy in which consumer credit is characterized by extremely high interest rates (i.e. Brazil). The authors used covariance-based structural equation modelling to analyse the data and test for mediation effects.

Findings

Individuals who inadvertently consider their credit limits a part of their current income or are typically anxious about money are prone to engage in impulsive buying and, consequently, risky indebtedness behaviour. By engaging in such indebtedness behaviour, individuals weaken their financial preparedness for emergencies, which potentially jeopardizes their overall financial well-being.

Research limitations/implications

As indebtedness is a highly sensitive issue, the self-report measures used may have produced social desirability bias.

Practical implications

This study discusses the responsibility of financial institutions to support consumers in building awareness on how to adequately use financial services and to provide credit access to high-risk consumers. Policymakers need to ensure that those in the private sector play fairly.

Originality/value

This study adds new knowledge about how destructive financial behaviours operate and impact marketing and consumers’ financial well-being. It theorizes about indebtedness by critically examining existing and newly developed concepts in the financial services marketing literature.
Developing global organizational leaders’ social capital (take out “introduction”)
Authors: Nakamura Yoshie Tomozumi
Published: June 2020

Purpose

The purpose of this study is to better understand what components impact the creation of organizational leaders’ social capital. The study further seeks to illuminate the effects of participating in a leadership development seminar on the creation of social capital in global contexts.

Design/methodology/approach

The data was collected through questionnaires from 540 leaders across 69 countries of a global firm. The hypotheses that were developed from existing literature were tested using regression analysis. Quantitative scales were created by averaging the responses to the pertinent survey items. The reliability of these scales was assessed with Cronbach’s alpha. Factor analysis was performed to assess whether the items from each scale measure distinct constructs.

Findings

The results of this research showed effects of three components (interactive opportunities, individual-owned resources and motivational interactivity constraints) on social capital. Specifically, the research substantiated that these components differently impacted advice ties and social relations.

Research limitations/implications

The study showed that firm leaders’ advice ties and social relations were differently impacted by identified components. With this in mind, organizations need to consider how they enhance and maintain the balance between advice ties and social relations among their leaders.

Originality/value

Empirical testing targeting organizational leaders in a global firm helped reveal findings in which variables impact their social capital. Based on the findings, this paper presents a framework that shows the identified components’ impacts on social capital ties and social relations.
Egyptian food experience of international visitors: a multidimensional approach
Authors: Mohamed Mohamed E.A. , Hewedi Mahamoud M. , Lehto Xinran , Maayouf Magdy
Published: June 2020

Purpose

Using destination brand experience as a conceptual lens and data evidence from international visitors to Egypt, the purpose of this study is to examine the relative impact of the various dimensions of local food experience on tourist overall food satisfaction and destination revisit intention.

Design/methodology/approach

Data from a convenience sample of international visitors to Cairo, Egypt, (N = 302) was quantitatively analyzed using the structural equation modeling approach to test the relationships among constructs.

Findings

Empirical results reveal that three components of destination food experiences – sensory, affective and behavioral – effectively explain tourists’ food satisfaction and destination revisit intention, while intellectual food experience was reported to only influence destination revisit intention. Interestingly, the effect of food experience satisfaction on destination revisit intention was not significant.

Research limitations/implications

This study identifies local food experience aspects that require to be managed at a strategic level and provides guidelines on how these aspects can be effectively managed.

Originality/value

This study is the first empirical application of a multidimensional experience model to the context of tourists’ local food experience; it identifies the multifaceted characteristics of local food experience that deserve scholars’ and marketers’ attention.
Green knowledge management and strategic renewal: a discursive perspective on corporate sustainability
Authors: Gauthier Jeffrey , Zhang Zuopeng (Justin)
Published: June 2020

Purpose

The purpose of this paper is to build theory concerning the role of discourse in strategic renewal and green knowledge management.

Design/methodology/approach

The approach entails an application of discourse theory to the strategy process literature, a review of the knowledge management (KM) literature and examination of examples in the context of organizations' sustainability initiatives.

Findings

A discourse-based model of green knowledge management, with associated research propositions that address each element of strategy renewal, is developed.

Research limitations/implications

The model and propositions in this paper may help to spur future management research that draws on a variety of discourse analytic tools, and advances our understanding of KM focused on environmental sustainability.

Originality/value

A discursive perspective on green knowledge management allows for a broader and more dynamic view of strategy process. This paper foregrounds the dynamic nature of strategy process in exploring the nature of discourse, and suggests that green knowledge management addresses a key megatrend that may form a foundation for strategic renewal.
Promoting interaction in online distance education: designing, implementing and supporting collaborative learning
Authors: Strauß Sebastian , Rummel Nikol
Published: June 2020

Purpose

Against the background of empirical research on computer-supported collaborative learning (CSCL), the purpose of this paper is to advocate implementing collaborative learning activities into online distance education courses to engage learners in interactive knowledge construction. This study uses empirical evidence to illustrate how educators can integrate collaborative learning and designated collaboration support into their instructional design.

Design/methodology/approach

This study presents a general review of research literature from the field of CSCL to highlight productive interaction between learners as key learning mechanisms, summarize core features of collaborative tasks, which promote interaction between learners and present group awareness tools and collaboration scripts as two complementary approaches to support groups during collaborative learning.

Findings

Empirical research suggests that collaborative learning is an effective learning activity and that incorporating collaborative learning into online courses benefits learners in terms of learning and social aspects such as social presence. However, to leverage the potential of collaborative learning, careful instructional design that promotes productive interaction between students is necessary.

Originality/value

This paper provides an overview on the topic of collaborative learning and how meaningful interaction between learners can be fostered. Specifically, this study details how collaborative tasks can be designed and how collaboration support can be used to provide students with opportunities for interaction that fosters acquiring new domain-specific knowledge as well as collaboration skills. To allow educators to design and incorporate collaborative learning activities into their own online teaching, the authors provide a theoretical basis for understanding the mechanisms behind effective collaborative learning as well as examples and practical considerations.
Arbitrage in gray markets and its impact on supply chain decisions
Authors: Lu Yali , Foropon Cyril R.H. , Wang Dandan , Xu Shuaishuai
Published: June 2020

Purpose

The purpose of this paper is to investigate the impacts of different gray markets’ structures on both supply chain decisions and associated profits.

Design/methodology/approach

Within the context of gray markets, using game theory approach in this paper, supply chains have been considered as assets of manufacturers, distributors and speculators, within which manufacturers sell products to distinctive markets either directly or through authorized distributors, while speculators buy products from a lower price market and then sell them in a higher price market. Our study has examined different decision variables within such a framework.

Findings

Considering a situation where one manufacturer sells its products either directly in one market (Market 1) or through its authorized distributor (Market 2), due to different products prices in both markets, results have shown that, when market elasticity is less than its critical value, a speculator can sell a gray market product arbitrage in market 2, whereas when the market elasticity is greater than its critical value, a speculator can sell a gray market product arbitrage in market 1. In addition, manufacturers—as leaders of Stackelberg game—are always the most profitable stakeholders within a gray market supply chain.

Practical implications

In this study, equilibrium results for each market have been obtained, optimal results have been compared, and accordingly, valuable insights have been developed. Such results would help managers to take better managerial decisions, as well as strategizing policies in gray markets.

Originality/value

In this paper, we have considered a gray market where both distributors and speculators exist and act as parallel channels. To the best of our knowledge, the extant literature focuses either on distributors or speculators, but never concurrently on both. In fact, the coexistence of one distributor and one speculator in a gray market will impact their own decisions, as well as both decisions and profits of other stakeholders, and hence, will exert an impact on the manufacturer side.
Deep-learning-assisted business intelligence model for cryptocurrency forecasting using social media sentiment
Authors: Yasir Muhammad , Attique Muhammad , Latif Khalid , Chaudhary Ghulam Mujtaba , Afzal Sitara , Ahmed Kamran , Shahzad Farhan
Published: June 2020

Purpose

Business Intelligence has gained a significant attraction in the recent past and facilitates managers for efficient business decision-making. Over the years, the attraction toward the cryptocurrency (CC) market has increased. Since the CC market is highly volatile, it is extremely sensitive to shocks and web data related to large events happening around the globe.

Design/methodology/approach

This research study provides a business intelligence model to predict five top-performing CCs. In this study, deep learning, linear regression and support vector regression (SVR) are used to predict CC prices. The sentiment of some mega-events is also used to enhance the performance of these models.

Findings

The results show that models of business intelligence such as deep learning and SVR provide better results. Moreover, the results show that the incorporation of social media sentiment data significantly improves the performance of the proposed models. The overall accuracy of the model improves approximately twofold when multiple event sentiments were incorporated.

Originality/value

The use of social media sentiment of global and local events for different countries along with deep learning for CC forecasting.
Development of IoT based data-driven agriculture supply chain performance measurement framework
Authors: Yadav Sanjeev , Garg Dixit , Luthra Sunil
Published: June 2020

Purpose

Performance measurement (PM) of any supply chain is prerequisite for improving its competitiveness and sustainability. This paper develops a framework for supply chain performance measurement (SCPM) for agriculture supply chain (ASC) based on internet of things (IoT). Moreover, this article explains the role of IoT in data collection and communication (SC visibility) based on the supply chain operation reference (SCOR) model.

Design/methodology/approach

This research identifies various key performance indicators (KPIs) and also their role in SCPM for improving its sustainability by using SCOR. Further, Shannon entropy is utilized for weighing the basic processes of SCPM and by using weights, fuzzy TOPSIS is applied for ranking of identified KPIs at metrics level 2 (deeper level).

Findings

“Flexibility” and “Responsiveness” have been reported as two most important KPIs in IoT based SCPM framework for ASC towards achieving sustainability.

Research limitations/implications

In this research, metrics are explained only at SCOR level 2. But, this research will guide the managers and practitioners of various organizations to set their benchmark for comparing their performance at different levels of business processes. Further, this paper has managerial implications to develop an effective system for PM of IoT based data-driven ASC.

Originality/value

By using IoT based data driven system, this article fills the gap between SCPM by measuring different SC strategies in their performance measurable form of reliable, responsive and asset management etc.
Organizational search and business model innovation: the moderating role of knowledge inertia
Authors: Yu Bo , Hao Shengbin , Wang Yu
Published: June 2020

Purpose

This study aims to explore the impact of organizational search (local and boundary-spanning search) on business model innovation (efficiency-centered/novelty-centered business model innovation) and the moderating role of knowledge inertia between them.

Design/methodology/approach

The relationships are examined through data provided by a sample of Chinese firms and by multiple hierarchical regressions.

Findings

Local search has a stronger effect on efficiency-centered business model innovation, whereas boundary-spanning search plays a stronger role in novelty-centered business model innovation. Knowledge inertia strengthens the effect of local search on efficiency-centered business model innovation but weakens the effect of boundary-spanning search on efficiency-centered business model innovation and the effect of local search on novelty-centered business model innovation.

Practical implications

The findings enable firms’ managers to understand the subtle ways in which organizational search interacts with knowledge inertia to affect business model innovation and may help them to make knowledge management efforts to harvest the full value of organizational search.

Originality/value

Previous studies have not examined the effect of different organizational search on different business model innovation from knowledge management perspective. With knowledge inertia as the moderator, the results reveal the contingent impact mechanism of organizational search on business model innovation, the findings provide fresh evidence that can bridge the gap between knowledge management and business model innovation.
Effects of supervisor bottom-line mentality on subordinate unethical pro-organizational behavior
Authors: Zhang Yun , He Bin , Huang Qihai , Xie Jun
Published: June 2020

Purpose

This study aims to examine how supervisor bottom-line mentality (BLM) influences subordinate unethical pro-organizational behavior (UPB), considering the mediating role of subordinate moral disengagement and the moderating role of their power-distance orientation.

Design/methodology/approach

The theoretical model was tested using two-wave data collected from employees of five firms in southern China.

Findings

Subordinate moral disengagement was found to mediate the positive relationship between supervisor BLM and subordinate UPB. Furthermore, for subordinates with high power-distance orientation, the positive relationship between supervisor BLM and subordinate moral disengagement and the indirect positive relationship between supervisor BLM and subordinate UPB were both strengthened.

Practical implications

First, organizations should train their employees to pursue goals ethically based on established standards and policies for acceptable behavior and to punish UPB. Second, organizations should strengthen employees' ethics and reduce their likelihood of moral disengagement. Finally, organizations should create an environment that allows subordinates to question their supervisors’ BLM.

Originality/value

First, the results demonstrate that supervisor BLM is an antecedent of subordinate UPB. Second, the study sheds important new light on how employees respond to supervisor BLM through cognitive processes. Third, it examines the moderating role of subordinate power-distance orientation between supervisor BLM, moral disengagement and UPB.
Value-in-use and service quality: do customers see a difference?
Authors: Medberg Gustav , Grönroos Christian
Published: June 2020

Purpose

The definition of value adopted by the current service perspective on marketing theory is value as value-in-use. Surprisingly, however, little attention has been given to the question of what constitutes value-in-use for customers in service contexts? Therefore, the aim of this study is to provide an empirical account of value-in-use from service customers' point of view.

Design/methodology/approach

To capture and analyze customers' experiences of value-in-use in the typical service context of retail banking, this study employed a narrative-based critical incident technique (CIT) and a graphical tool called the value chart.

Findings

The study identified seven empirical dimensions of positive and negative value-in-use: solution, attitude, convenience, expertise, speed of service, flexibility and monetary costs. Interestingly, these value-in-use dimensions overlap considerably with previously identified dimensions of service quality.

Research limitations/implications

The concepts of service quality and value-in-use in service contexts seem to represent the same empirical phenomenon despite their different theoretical traditions. Measuring customer-perceived service quality might therefore be a good proxy for assessing value-in-use in service contexts.

Practical implications

As the findings indicate that service quality is the way in which service customers experience value-in-use, service managers are recommended to focus on continuous quality management to facilitate the creation of value-in-use.

Originality/value

This study is the first to explicitly raise the notion that in the minds of service customers, value defined as value-in-use and service quality may represent the same empirical phenomenon.
Internal audit function and real earnings management practices in an emerging market
Authors: Ghaleb Belal Ali Abdulraheem , Kamardin Hasnah , Al-Qadasi Adel Ali
Published: June 2020

Purpose

This study aims to investigate the monitoring role of internal audit function (IAF) on real earnings management (REM) practices. It examines the effect of investment in IAF (IIAF) and IAF sourcing arrangements on REM, unlike prior literature which has mainly examined the effects of IIAF on accrual-based earnings management.

Design/methodology/approach

This study uses a sample of 1,056 observations from an emerging market, Malaysia, between 2013 and 2016. Feasible generalised least square (FGLS) regression is used to analyse the data. To corroborate the results of this study, the authors use an ordinary least square (OLS) regression model with robust standard errors adjusted and also consider alternative REM measures.

Findings

The results of this study suggest that IIAF has a significant negative relationship with REM practices. Further, in-house IAF sourcing has a significant negative association with REM. The additional analysis supports the main results confirming the essential role of IAF in reducing REM in the Malaysian market.

Practical implications

The evidence relates to the important role of IAF in mitigating REM practices. High-quality of IAF impairs managers’ ability to manage earnings in their own interests. The findings may be useful in informing regulators, managers, shareholders and other investors, as well as researchers, about improving the role of IAF.

Originality/value

This study contributes to the existing literature by providing the first evidence of the significant role of IIAF and IAF sourcing arrangements in mitigating REM in an emerging country.
Hall effects on radiated magneto-power-law fluid flow over a stretching surface with power-law velocity slip effect
Authors: Ali Asgar , Jana R.N. , Das S.
Published: June 2020

Purpose

This paper aims to assess the effectiveness of Hall currents and power-law slip condition on the hydromagnetic convective flow of an electrically conducting power-law fluid over an exponentially stretching sheet under the effect of a strong variable magnetic field and thermal radiation. Flow formation is developed using the rheological expression of a power-law fluid.

Design/methodology/approach

The nonlinear partial differential equations describing the flow are transformed into the nonlinear ordinary differential equations by employing the local similarity transformations and then solved numerically by an effective numerical approach, namely, fourth-order Runge–Kutta integration scheme, along with the shooting iteration technique. The numerical solution is computed for different parameters by using the computational software MATLAB bvp4c. The bvp4c function uses the finite difference code as the default. This method is a fourth-order collocation method. The impacts of thermophysical parameters on velocity and temperature distributions, skin friction coefficients and Nusselt number in the boundary layer regime are exhibited through graphs and tables and deliberated with proper physical justification.

Findings

Our investigation conveys that Hall current has an enhancing behavior on velocity profiles and reduces skin friction coefficients. An increase in the power-law index is observed to deplete velocity and temperature evolution. The temperature for the pseudo-plastic (shear-thinning) fluid is relatively higher than the corresponding temperature of the dilatant (shear-thickening) fluid. The streamlines are more distorted and have low intensity near the surface of the sheet for the dilatant fluid than the pseudo-plastic fluid.

Social implications

The study is pertinent to the expulsion of polymer sheet and photographic films, hydrometallurgical industry, electrically conducting polymer dynamics, magnetic material processing, solutions and melts of polymer processing, purification of molten metals from nonmetallic. The results obtained in this work can be relevant in fluid mechanics and heat transfer applications.

Originality/value

The present problem has, to the authors' knowledge, not communicated thus far in the scientific literature. A comparative study with the published works is conducted to verify the accuracy of the present study. The results obtained in this analysis are significant in providing the standards for validating the accuracies of some numerical or empirical methods.
Research on the effects of L-carnitine and trans-chalcone on endoplasmic reticulum stress and oxidative stress in high-fructose corn syrup-fed rats
Authors: Unsal Velid , Deveci Köksal , Ozmen Zeliha Cansel , Tumer Mehmet Kemal
Published: June 2020

Purpose

The debate on the metabolic effects of high fructose corn syrup (HFCS) continues. The deterioration of endoplasmic reticulum (ER) homeostasis is called ER stress. Glucose-regulated protein-78 (GRP-78) and X-box binding protein-1 (XBP-1) are key markers of ER stress and the therapeutic targets of diseases. Sterol regulatory element binding protein-1c (SREBP-1c) is the most important transcription factor that regulates the expression of enzymes for fatty acid synthesis. The purpose of this paper is to research the effects of L-carnitine and trans-chalcone on ER stress and oxidative stress parameters, and to explore the therapeutic potential of L-carnitine and trans-chalcone molecules.

Design/methodology/approach

Forty male wistar albino rats randomly selected were divided into five groups. All groups are fed with standard chow (ad libitum). While Group I was fed with drinking water, Group II, III, IV and V were fed with water containing 15% HFCS. L-carnitine was given to Group IV and trans-chalcone to Group V, and both were dissolved with DMSO and given intraperitoneally. Group III was not given anything additional.

Findings

While the amount of water consumption of HFCS-fed rats has increased, the amount of feed consumption has decreased. The weights of rats in Group II and Group III have increased significantly compared to Group I (p= 0.001,p= 0.001 respectively). In Group III, GRP78, XBP-1; malondialdehyde level (p< 0.001,p= 0.001,p= 0.041); total cholesterol, triglyceride, LDL levels (p= 0.001,p< 0.001,p= 0.009,p= 0.001, respectively) have increased significantly.

Originality/value

To the best of the authors’ knowledge, this study is the first report to show that excessive HFCS consumption causes oxidative stress and ER stress. The antioxidant and antiobesity properties of trans chalcone have been demonstrated. Extensive experimental and clinical studies should be conducted.
Thin-film based sensor for the selective detection of mercury (Hg2+) ions at the picomolar range
Authors: Rotake Dinesh Ramkrushna , Darji Anand , Singh Jitendra
Published: June 2020

Purpose

The purpose of this paper is a new thin-film based sensor proposed for sensitive and selective detection of mercury (Hg2+) ions in water. The thin-film platform is easy to use and quick for heavy metal ions (HMIs) detection in the picomolar range. Ion-selective self-assembled monolayer's (SAM) of thiol used for the detection of HMIs above the Au/Ti top surface.

Design/methodology/approach

A thin-film based platform is suitable for the on-field experiments and testing of water samples. HMIs (antigen) and thiol-based SAM (antibody) interaction results change in surface morphology and topography. In this study, the authors have used different characterization techniques to check the selectivity of the proposed method. This change in the morphology and topography of thin-film sensor checked with Fourier-transform infrared spectroscopy, surface-enhanced Raman scattering spectroscopy, atomic force microscopy and scanning electron microscopy with energy dispersive x-ray analysis used for high-resolution images.

Findings

This thin-film based platform is straightforward to use and suitable for real-time detection of HMIs at the picomolar range. This thin-film based sensor platform capable of achieving a lower limit of detection (LOD) 27.42 ng/mL (136.56 pM) using SAM of Homocysteine-Pyridinedicarboxylic acid to detect Hg2+ions.

Research limitations/implications

A thin-film based technology is perfect for real-time testing and removal of HMIs, but the LOD is higher as compared to microcantilever-based devices.

Originality/value

The excessive use and commercialization of nanoparticle (NPs) are quickly expanding their toxic impact on health and the environment. The proposed method used the combination of thin-film and NPs, to overcome the limitation of NPs-based technique and have picomolar (136.56 pM) range of HMIs detection. The proposed thin-film-based sensor shows excellent repeatability and the method is highly reliable for toxic Hg2+ions detection. The main advantage of the proposed thin-film sensor is its ability to selectively remove the Hg2+ions from water samples just like a filter and a sensor for detection at picomolar range makes this method best among the other current-state of the art techniques.
Adopting a digital transformation strategy to enhance business network commons regeneration: an explorative case study
Authors: Zoppelletto Alessia , Bullini Orlandi Ludovico , Rossignoli Cecilia
Published: June 2020

Purpose

This article aims to understand whether and how a digital transformation strategy (DTS) can strengthen the relationship between network organizations and the generation/regeneration of their business network commons (BNC). Further, it investigates the role of the DTS in managing the BNC, a critical source of business network success.

Design/methodology/approach

A two-year longitudinal case study of an Italian business network operating in the wine sector was conducted.

Findings

This study provides theoretical insights into the digital, sustainable shift of a business network. On combining a network's business strategy and its DTS, digital resources are a key driver to promote BNC regeneration. A DTS undertaken to manage, regenerate and preserve the BNC can positively affect organizational variables, such as participatory architecture, and the network-level organizational integration and can help in preventing opportunistic behaviors affecting the BNC. Moreover, the DTS supports quality and social responsibility.

Research limitations/implications

This study focuses on an Italian case and its findings are hence not generalizable. It would be interesting to study sustainable business networks' digital shift in different socioeconomic contexts as well as in different industry settings.

Practical implications

Network SMEs and other stakeholders (institutions, competitors and consumers) can foster the transition from a “business-as-usual” strategy to a long-term strategy for digitalized management of common resources.

Originality/value

The study is at the intersection of, and contributes to, several research streams. It contributes to the digital transformation literature by adding information on the positive externalities of digitalization in the social and economic environment. It also contributes to the early streams of organizational and managerial literature on the BNC.
Design of symmetrical half-bridge converter with a series coupling capacitor
Authors: Rashmi Ruchi , Jagtap Shweta
Published: June 2020

Purpose

With the advancement of technology, size, cost, and losses of the switched mode power supply (SMPS) have been decreasing. However, due to the high frequency switching, design of magnetic drives and isolation circuits are becoming a crucial factor in SMPS. This paper presents design criteria, procedure and implementation of AC-DC half bridge (HB) converter with lower cost, smaller size and lower voltage stress on the power switch.

Design/Methodology/approach

The HB converter is designed in a symmetrical mode with a series coupling capacitor. Isolated power supplies are used for the converter and control circuit. Further, a transformer based isolated gate driver is used to drive both MOSFETs. The control IC works in voltage control mode to regulate voltage by controlling the duty cycle of the MOSFETs.

Findings

Control characteristics and performance of the HB converter is simulated using the MATLAB software and prototype of 170 W HB converter is built to validate the analytical results under variable load current and source voltage. The power quality and variation of load voltage at 2 A, 5 A, 7 A are reported.

Originality/value

This paper presents the design of a low-cost HB converter in a symmetrical mode which saves the additional cost of symmetric correction circuit normally required in asymmetrical mode design. This paper also focuses on the selection of primary and secondary side switch, series coupling capacitor, commuting diode, isolated drive and charge equalizer resistor.
Lithology‐dependent seismic anisotropic amplitude variation with offset correction in transversely isotropic media
Authors: Babasafari Amir Abbas , Ghosh Deva Prasad , Ahmed Salim Ahmed Mohammed , Kordi Masoumeh
Published: June 2020

Analysis of amplitude variation with offset is an essential step for reservoir characterization. For an accurate reservoir characterization, the amplitude obtained with an isotropic assumption of the reservoir must be corrected for the anisotropic effects. The objective is seismic anisotropic amplitude correction in an effective medium, and, to this end, values and signs of anisotropic parameter differences (Δδ and Δε) across the reflection interfaces are needed. These parameters can be identified by seismic and well log data. A new technique for anisotropic amplitude correction was developed to modify amplitude changes in seismic data in transversely isotropic media with a vertical axis of symmetry. The results show that characteristics of pre‐stack seismic data, that is, amplitude variation with offset gradient, can be potentially related to the sign of anisotropic parameter differences (Δδ and Δε) between two layers of the reflection boundary. The proposed methodology is designed to attain a proper fit between modelled and observed amplitude variation with offset responses, after anisotropic correction, for all possible lithofacies at the reservoir boundary. We first estimate anisotropic parameters, that is, δ and ε, away from the wells through Backus averaging of elastic properties resulted from the first pass of isotropic pre‐stack seismic inversion, on input data with no amplitude correction. Next, we estimate the anisotropic parameter differences at reflection interfaces (values and signs of Δδ and Δε). We then generate seismic angle gather data after anisotropic amplitude correction using Rüger's equation for the P‐P reflection coefficient. The second pass of isotropic pre‐stack seismic inversion is then performed on the amplitude‐corrected data, and elastic properties are estimated. Final outcome demonstrates how introduced methodology helps to reduce the uncertainty of elastic property prediction. Pre‐stack seismic inversion on amplitude‐corrected seismic data results in more accurate elastic property prediction than what can be obtained from non‐corrected data. Moreover, a new anisotropy attribute (ν) is presented for improvement of lithology identification.
Integrating the Bright and Dark Sides of Corporate Volunteering Climate: Is Corporate Volunteering Climate a Burden or Boost to Employees?
Authors: Zhang Zhe , Wang Juan , Jia Ming
Published: June 2020

Conventional wisdom is that a corporate volunteering climate should be beneficial to employees. We challenge this perspective by integrating person–environment fit and conservation of resources theories and providing an integrative model that examines how and when corporate volunteering climate produces positive and negative consequences for employees. Using a two‐wave time‐lagged study of 283 employees in 42 companies, our multilevel model shows that positive emotions mediate the relationship between corporate volunteering climate and work engagement, and perceived role overload mediates the relationship between corporate volunteering climate and work–family conflict. Employees’ communal orientation moderates the positive relationship between corporate volunteering climate and positive emotions, whereas competitive orientation moderates the positive relationship between corporate volunteering climate and perceived role overload. Communal orientation moderates the indirect effect between corporate volunteering climate and work engagement via positive emotions, but competitive orientation moderates the indirect effect between corporate volunteering climate and work–family conflict via perceived role overload. Our study provides balanced insights to help understand the benefits and costs of corporate volunteering climate in work and non‐work domains.
Trade development between China and countries along the Belt and Road: A spatial econometric analysis based on trade competitiveness and complementarity
Authors: Chen Jiyong , Chen Dabo , Yao Aiping
Published: June 2020

This paper empirically analyses the effect of trade competitiveness and complementarity on the trade development between China and the countries along the Belt and Road (B&R). The study first measures the trade competitiveness and the complementarity between China and the countries along the B&R by using the trade competitiveness coefficient (TCC) and the trade complementarity index (TCI). Then a spatial gravity model is constructed to analyse the effect of trade competitiveness and complementarity on trade development between China and the countries along the B&R. We use generalized method of moments (GMM) and spatial filtering technology to verify the robustness of the model. The results show that the GDP of China and the countries along the B&R, the land area of countries along the B&R, trade complementarity, common language, free trade agreements (FTA), and the B&R Initiative significantly promote the trade development between China and the countries along the B&R, whereas the geographical distance between countries and trade competitiveness significantly inhibit it. Finally, to promote the trade development between China and the countries along the B&R, the present paper puts forward suggestions including improving trade promotion policies between China and the countries along the B&R and vigorously expanding cooperation with complementary industries in the countries along the B&R to enhance trade dependence.
AIEgens: An emerging fluorescent sensing tool to aid food safety and quality control
Authors: Huang Xiaolin , Guo Qian , Zhang Ruoyao , Zhao Zheng , Leng Yuankui , Lam Jacky W. Y. , Xiong Yonghua , Tang Ben Zhong
Published: June 2020

As a global public health problem, food safety has attracted increasing concern. To minimize the risk exposure of food to harmful ingredients, food quality and safety inspection that covers the whole process of “from farm to fork” is much desired. Fluorescent sensing is a promising and powerful screening tool for sensing hazardous substances in food and thus plays a crucial role in promoting food safety assurance. However, traditional fluorphores generally suffer the problem of aggregation‐caused quenching (ACQ) effect, which limit their application in food quality and safety inspection. In this regard, luminogens with aggregation‐induced emission property (AIEgens) showed large potential in food analysis since AIEgens effectively surmount the ACQ effect with much better detection sensitivity, accuracy, and robustness. In this contribution, we review the latest developments of food safety monitoring by AIEgens, which will focus on the molecular design of AIEgens and their sensing principles. Several examples of AIE‐based sensing applications for screening food contaminations are highlighted, and future perspectives and challenges in this emerging field are tentatively elaborated. We hope this review can motivate new research ideas and interest to aid food safety and quality control, and facilitate more collaborative endeavors to advance the state‐of‐the‐art sensing developments and reduce actual translational gap between laboratory research and industrial production.
Post‐Brexit Policies for a Resilient Arable Farming Sector in England
Authors: Vigani Mauro , Urquhart Julie , Black Jasmine Elizabeth , Berry Robert , Dwyer Janet , Rose David Christian
Published: June 2020

With the withdrawal of the UK from the European Union and increasing pressures from climate change, English arable farming resilience is in a fragile position. Most Brexit impact assessments have focused on quantitative analysis, however here we take a qualitative approach to assess how future trade agreements could impact the resilience of the UK arable farming system. We discuss the main strategies that are currently taken by English arable farmers to improve resilience using evidence from a large‐scale survey in the East of England. Using information from a multi‐stakeholder workshop, we look at arable farming resilience in three forms characteristic of the farming system; namely, robustness, adaptability and transformability and how these relate to and are potentially influenced by three different Brexit trade scenarios. Stakeholders’ recommendations suggest that a ‘hard’ no‐deal scenario will require policies for social protection of farmers in more vulnerable rural areas, while in a ‘softer’ scenario a ‘public money for public goods’ policy could be implemented effectively by learning from previous environmental schemes. Nevertheless, resilience can be enhanced only by addressing structural and policy issues, such as generational renewal, advice and extension, tenancy duration limits and smarter PPP regulations, regardless of what post‐Brexit deal with the EU finally emerges.
Human sperm vitrification: A scientific report
Authors: Schulz Mabel , Risopatrón Jennie , Uribe Pamela , Isachenko Evgenia , Isachenko Vladimir , Sánchez Raúl
Published: June 2020

Background

The sperm vitrification developed by this group is based on the ultrarapid freezing of a vitrification solution composed of a non‐permeable cryoprotectant (saccharides and protein), in which previously selected spermatozoa are resuspended, free of seminal plasma, and then plunged directly into liquid nitrogen. Compared to traditional sperm freezing, vitrification does not cause chemical or physical damage to the intracellular structures and reduces the damage to the plasma membrane because no ice crystals form, thus preserving motility and DNA integrity.

Objectives

This manuscript is a review of the vitrification methodology developed by the authors’ research group, including studies showing the application in human reproduction therapy.

Materials and methods

The authors perform a review of the work initiated more than a decade ago by this research group, on the implementation of sperm vitrification, a more effective technique for cryopreservation of human spermatozoa, discussing the results obtained by other authors and the projection of this technique.

Results and discussion

The vitrification technique has been developed in selected spermatozoa free of seminal plasma supplemented with saccharides such as sucrose, trehalose, and dextran, together with albumin, providing a high motility rate and protective structures of the cytoskeleton. In patients, it can be used to preserve their fertility for oncological reasons, genetics, inflammatory diseases, or reproductive medicine techniques. The possibility that vitrified spermatozoa can be preserved at temperatures of −80°C can simplify sample storage, optimizing the space and time as well as operator safety.

Conclusion

Vitrification techniques have demonstrated the preservation of selected spermatozoa without seminal plasma and with non‐permeable cryoprotectants and protein. Currently, it is one of the most effective ways to maintain sperm function and has been used in in vitro fertilization or intrauterine insemination in humans, achieving healthy live births.
Venlafaxine‐induced damage to seminiferous epithelium, spermiation, and sperm parameters in rats: A correlation with high estrogen levels
Authors: de Santi Fabiane , Beltrame Flávia L. , Rodrigues Beatriz M. , Junior Marcio J. V. P. , Scaramele Natália F. , Lopes Flávia L. , Cerri Paulo S. , Sasso‐Cerri Estela
Published: June 2020

Background

Venlafaxine (selective serotonin and norepinephrine reuptake inhibitor) use has increased worldwide. However, the impact of venlafaxine on testes and sperm parameters has not been investigated.

Objectives

We evaluated venlafaxine impact on testicular and sperm parameters and verified whether the changes are reversible.

Methods

Animals from venlafaxine‐35 days and venlafaxine‐65 days groups received 30 mg/kg of venlafaxine for 35 days. Control‐35 days and control‐65 days received distilled water. In control‐65 days and venlafaxine‐65 days, the treatment was interrupted for 30 days. Sperm concentration, morphology, motility, and mitochondrial activity were analyzed. Number of step 19 spermatids (NLS), frequency of tubules with spermiation failure, Sertoli cells number, and TUNEL‐positive germ cells were quantified. Testicular aromatase, connexin 43 (Cx43) immunoexpression, Cx43 protein levels, and Cx43 expression were evaluated. Either intratesticular testosterone or estrogen levels were measured.

Results

Venlafaxine impaired sperm morphology, reduced sperm concentration, mitochondrial activity, and sperm motility. The frequency of tubules with spermiation failure and NLS increased in parallel to increased Cx43 immunoexpression; mRNA and protein levels; and aromatase, testosterone, and estrogen levels. An increase in germ cell death and decreased Sertoli cells number were observed. In venlafaxine‐65 days, except for sperm motility, mitochondrial activity, Sertoli cells number, and germ cell death, all other parameters were partially or totally recovered.

Conclusion

Venlafaxine increases testosterone aromatization and Cx43. This drug, via high estrogen levels, disturbs Sertoli cells, induces germ cell death, and impairs spermiation and sperm parameters. The restoration of spermiation associated with the decreased Cx43 and hormonal levels in venlafaxine‐65 days reinforces that high estrogen levels are related to venlafaxine‐induced changes. The presence of damaged Sertoli cells, germ cell death, and low sperm motility in venlafaxine‐65 days indicates that interruption of treatment for 30 days was insufficient for testicular recovery and points to a long‐term estrogen impact on the seminiferous epithelium.