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A theoretical approach for optimizing sliding-mode triboelectric nanogenerator based on multi-parameter analysis
No full textOptimized design of sliding-mode triboelectric nanogenerator (TENG) that is triggered by relative sliding between dielectric layers through a friction process forms one of the key focuses in this community since it may enhance the feasibility of real applications in industries. We propose here a theoretical model based on multi-parameter analysis to provide a rational optimization strategy for design of sliding mode TENG. By combining multiple parameters into dimensionless variables, the normalized output performance is expressed by virtue of two compound parameters. The scaling laws are achieved between the normalized electric output and these compound parameters, involving device dimensions (sizes, dielectric layer thickness), electrical properties of the electrode and dielectric materials, loading conditions (loading force, frequency and motor process), and the circuit conditions (open/short circuit and load resistance). The scaling laws may provide a more comprehensive and rational optimization strategy for sliding-mode TENG based on multi-parameter analysis and may help to enhance the output performance of the device as either a smart sensor or an energy harvester.
A theoretical model for optimizing sliding-mode TENG based on multi-parameter analysis is established to simulate the normalized output performance of sliding-mode TENG in various working conditions. The theoretical results agree very well with experimental data. According to scaling laws between dimensionless output voltage and compound parameters, the optimal combination of all the parameters considered simultaneously could be acquired for the best output voltage, providing a more rational optimization strategy for device design. [Display omitted]
•A theoretical approach for optimizing sliding-mode TENG based on multi-parameter analysis is proposed.•The scaling laws may help acquire the optimal combination with all the parameters considered simultaneously.•The output performance may be enhanced by tuning multiple parameters or varying single parameter with the others fixed
The impact of IT project management tools and leadership self-efficacy on project success
No full textThe present study is concerned with improving IT project outcomes, specifically in relation to the possible effects of Leadership Self-Efficacy (LSE) and the use of Information Technology Project Management (ITPM) tools. Though logically connected to effective project work and outcomes, the literature review on project management, leadership, LSE and tools did not uncover empirical studies raising the questions of the relationship of these factors with project outcomes or studies seeking to determine the direct effect of each of these two factors on project outcomes. The present study focuses on filling this gap in research by addressing these questions and presents a research model that has provided statistically reliable evidence of the positive impact of each of these two factors on the odds of project outcomes at the component level of the project dimension.The study was designed based on an abbreviated version of an IT project, consisting of four project dimensions: communication management, requirements gathering, risk management, and project support transition, and two dimension-specific ITPM tools for each dimension. Data was collected using 1) a questionnaire to measure each participant’s level of LSE, 2) a survey of tool use and outcomes in the four dimensions for each of ten projects managed by each participant, and 3) recorded personal interviews with twenty-nine highly qualified and experienced IT project management professionals who have cumulatively handled 1,000+ projects in 400+ companies across four industries (high-tech, retail, automotive and logistics).The data from the LSE questionnaire was used to assess each participant’s level of LSE. The LSE data and the data of each participant’s reports on ten projects was analysed using logistic regression. The results showed that 1) project managers’ possession of LSE and 2) the utilisation of dimension-specific ITPM tools each increased the odds of successful outcomes in each project dimension with statistically significant results with the exception of one tool.The interview transcripts were analysed qualitatively for trends in these experts’ viewpoints regarding the practical reality of IT project management. With the aim of gleaning insights into the possible relationship of LSE and project managers’ perspectives on success and failure and on tool use, the interview transcripts were further analysed quantitatively with a word to vector text analysis (a Natural Language Processing technique) for word associations regarding concepts of success, failure, ITPM tools, and related project manager activities. The results showed a notable difference in degree of cosine similarity for word associations of selected word pairs found in the transcripts of the group with higher LSE scores compared to those of the group with lower LSE scores, in almost all cases, providing more evidence that the factor of LSE is influential.This study makes important contributions to the background literature on LSE and project management and offers a reproducible research design that yielded statistically reliable results that confirm the influences of LSE and tools on project dimension outcomes. Furthermore, this study applied a text analysis technique to explore the factor of LSE and word associations regarding IT project dimensions and tools. These contributions, along with insights from the literature review, can be applied to training and development for IT project managers. Besides its immediate applications, this study has taken a step toward empirically and statistically researching factors contributing to IT project outcomes and provides a base study and context for future research in this area
A comparative case study: towards sustainable management of e-waste in the Kingdom of Saudi Arabia
No full textManagement of electrical and electronic waste (e-waste) becomes an increasing global concern because of rapid changing in technologies associated with tendency of people to keep up with the most recent technologies causing an increased volume rate of e-waste. This study compared and critically appraised three e-waste management models (producer responsibility, not producer responsibility, and sharing responsibility) currently applied in Malaysia and the United States of America (USA), in an attempt to explore best management practices that can be adopted in the Kingdom of Saudi Arabia. The data presented in this paper are secondary data derived from a wide range of authoritative sources. This study recommends the sharing responsibility model to effectively manage the growing rate of e-waste in the Kingdom of Saudi Arabia
Factors affecting the utilization of specific Turnaround Strategies by SMEs, during an Economic Depression
No full textGreece has been experiencing the consequences of a deep economic crisis for nine consecutive years since 2008. This has adversely affected the entire business sector of the country. Due to its unique business sector characteristics, meaning the fact that in Greece the greatest percentage of the companies are micro SMEs and SMEs, the conditions during the economic crisis years (2008-2016) have significantly worsened. The socioeconomic conditions in Greece since the beginning of the crisis, combined with the characteristics of the SMEs and the SMEs’ organizational level, are the sources behind the problems experienced by these SMEs.This present research studied the identification of a specific Turnaround Strategies Mix, as well as the factors affecting those strategies, and furthermore the impact of those strategies on the Greek SMES’ performance and viability. Despite the fact that many researchers have supported that organizational change and top-level management replacement should be followed by Retrenchment Strategies for declining SMEs’ survival, the present research investigates and identifies Turnaround Strategies, focusing on their ability to improve the SMEs’ viability and survival. This has been made effective since the researcher, based on previous researchers’ Turnaround models, conducted the present research’s model by altering the Investment Strategies, instead of the Retrenchment ones. The business environment complexity into which the sequence of these Turnaround Strategies (Turnaround Process) takes place, creates factors that affect this process. This research examines and identifies as critical factors, the impact of the SMEs’ owners or managers’ personal profile characteristics, the economic crisis effects and the firm’s debt extent-leverage that affect the Turnaround Strategies Mix adopted by the Greek SMEs in order to achieve their survival and improve their financial performance during deep economic recession circumstances. The scope of the research was to analyse the collected data from the conducted sample of 209 Ionian Islands Greek SMEs and the Turnaround Strategies they implemented as a result of the economic crisis and the deterioration of their profitability. The main Turnaround Strategies investigated were Organizational Change, Investment vs Retrenchment, Innovation Strategies and Market Strategies (including Export Orientation). The research conducted was based on the proposed model and studied the operating SMEs in the Ionian Island region in Greece while a new prototype Turnaround Strategies Measurement Instrument (TSMI) was introduced by the researcher to evaluate those Strategies. The results of the present research showed that the Turnaround Strategy Mix, which was used by the research’s proposed model, positively affect the performance, viability and survival of the SMEs during economically stressed conditions. Furthermore, this research’s findings showed the positive impact on the Greek micro SMEs and SMEs’ performance and viability from the use of a specific Turnaround Strategies Mix during economic crisis circumstances. Therefore these findings could be very important for the SMEs’ owners or managers, as well as researchers, government organizations, policy makers, and, business advisors.The present study contributes to knowledge (originality) at a theoretical level with the measurement instrument (TSMI) introduced, adding the relevant gap in the Turnaround literature, as well as on the empirical level by proposing a specific Turnaround Strategy Mix for the Greek SMEs, on the one hand, and by identifying those factors that affect the utilization of specific Turnaround Strategies by the Greek SMEs on the other hand
"Life doesn’t give you bumpers”: a coming or going of age in Juno and Boyhood
No full textThis article examines two twenty-first century films, Juno (2007) and Boyhood (2014), arguing that they are refreshingly different from most previous “coming of age” movies in the way that they avoid the usual clichés associated with such films. Whereas many earlier movies tend to make a single event the turning point in young characters’ lives, these two films deliberately wrong-foot the audience by steering round such predictable scenarios, and give a more credible depiction of characters in their ongoing dealing with the comings and goings of age, whether they are young or old. It is suggested that the films achieve this both in terms of their content and also in their structure, seeking to prioritize the fabula over the sjuzhet. They also have endings that are more “feminine,” avoiding the traditional, climactic male ending
Introduction: Robert Snape and Karl Spracklen
No full textIntroduction to special issue of Leisure-Loisir - Histories of Modern Leisur
Interference-free space-time block codes with directional beamforming for future networks
No full textAs the evolving communication standards would leverage on high data rates and low power consumption, future communication systems must be able to demonstrate these strengths. Space-time block codes (STBC) and quasi-orthogonal STBC (QO-STBC) including beamforming are multiple-input multiple output (MIMO) system design techniques used to improve data rates and reduce bit error ratio (BER). STBCs for larger antenna configurations use QO-STBC schemes which suffer from self-interference problems. The self-interference in QO-STBC systems diminishes the data rates and worsen the BER. In this study, we present three (3) methods of overcoming the self-interference problems in QO-STBC systems. We implement the interference-free QO-STBC systems with directional beamforming to improve the data rates and also reduce the BER. The results show significantly improved BER performance when the interferences are eliminated. An additional 3dB gain is achieved at 1
Development of 3D biocomposite aerogels for soft tissue engineering applications
No full textCurrent approaches in developing porous 3D scaffolds face various challenges, such as failure of mimicking extracellular matrix’s (ECM) native building blocks and its functionality. Biopolymer based aerogels have shown to provide structural similarities to the ECM owing to their 3D format and a highly porous structure with interconnected pores. Utilising functional biopolymers (such as hydrophilic polysaccharides and proteins) to fabricate aerogels through freeze-drying technique is found to improve swelling degree, support cell growth and offer rapid enzymatic biodegradation, making such biomaterials appropriate as 3D scaffolds in tissue regeneration. Utilising hydrophilic natural biopolymers is associated with drawbacks such as poor mechanical properties and fast dissolvability. The present research focuses on using cellulose nanofibers (CNF) as a suspension to support the development of porous 3D aerogel biocomposites, compensating the drawbacks associated with natural biopolymers. To develop the biocomposites, CNF is blended with gelatine and starch to obtain aerogels with optimal physicochemical, mechanical and biological characteristics intended to be used as 3D scaffolds for tissue regeneration. The CNF biocomposites with various ratios of CNF: starch (CNF-starch) and CNF: gelatine (CNF-GEL)) were synthesized, and their properties were investigated in terms of physicochemical, mechanical and biological characteristics. Furthermore, Epichlorohydrin (EPH) was used to investigate the effect of chemical crosslinking on the molecular interaction of CNF-starch and CNF-GEL. Ultimately, chemical crosslinking helped to improve the mechanical resilience of the aerogels. The tunability of the physiochemical, mechanical and biological properties of the developed biocomposites makes such structure a great candidate as scaffolds for tissue engineering applications. Both in-vitro and in-vivo studies revealed satisfactory biocompatibility for the crosslinked CNF-GEL biocomposites using dermal fibroblasts. Furthermore, curcumin, a natural material with inherent antimicrobial properties, was added into the CNF-GEL biocomposite as an active molecule agent to improve the antimicrobial and anti-inflammatory responses of the scaffolds. The addition of curcumin was effective against both gram-positive and gram-negative due to the lack of existing antimicrobial characteristics in both CNF and gelatine
“Magic Mirror on the Wall”: is Nordic walking or rambling better for your mental well-being?
No full textThere is accumulating evidence that walking has health benefits. While millions of people in the United Kingdom have long benefitted from rambling, Nordic walking is a relative newcomer to the shores of Britain. Which of these forms of walking is better for your mental wellbeing? This study set out to compare both forms of walking and measured their effects on mental wellbeing using the Warwick Edinburgh Mental Well-being Scale (WEMWBS), through an on-line survey. In addition both groups of walkers were asked about socio-environmental influences on their walking. Some 508 participants completed the online survey, which assessed socio-environmental factors on participation in both walking activities and mental well-being. This study showed both walking groups had higher mental well-being scores than the “normal population” for the WEMWBS. However, there were no significant differences in contribution to mental well-being between the two walking groups. Socio-environmental analysis revealed that in Nordic walking the role of the instructor was critical, whereas in rambling friends’ support, weather conditions and the aesthetics of the environment were important factors for participation. This study diversified the concept of leisure walking by distinguishing between rambling and Nordic walking in terms of their differing contributions towards mental well-being