The Effect of the Size of Pinning Centres on the Critical Current Density in High-Temperature Superconductors

Superconductor materials that have no resistance to the flow of electricity are one of the last great frontiers of scientific discovery. Superconductivity in these materials occurs particularly in the copper-oxide (CuO2) planes. However, since these materials are type-II superconductors, magnetic fields can penetrate these materials in quantized amounts of flux called vortices without completely destroying superconductivity, but producing some resistance, due to vortex motion. In order to overcome the resistance problem, vortices must be pinned to prevent their motion and hence eliminate the resistance. In this work study we have performed extensive numerical simulations to study the effect of the size of pinning centres on the critical current density of driven vortex lattices interacting with square periodic arrays of pinning sites. This has been carried out at different temperatures and for several values of pinning strengths. We have solved the over damped equation of vortex motion taking into account the vortex-vortex repulsion interaction, the attractive vortex-pinning interaction, the thermal force, and the driving Lorentz force. We have found that, while the critical current density increases with pinning size at high temperatures, it is almost independent of pinning size at low temperatures. We have also found that increasing the size of the pinning centers suppresses the rate at which the critical current density decreases with temperature

Research in Public Relations

Research is essential element in public relation. It’s not necessary to have been ambiguous, expensive or complex. There is one way to ensure that Public Relation research arrives on time, on budget and gives the right result to create organizational. This paper will discover the importance of research and research steps in public relations in the UAE organizations. It ended that many PR offices do care about the research but still research needs more awareness and development in the future. More researches need to be collected in the PR field

An analysis of a benchmarking initiative to help government entities to learn from best practices - the 'Dubai We Learn' initiative

Purpose: Benchmarking has been recognised as one of the most widely adopted business improvement tools. Whilst there have been many independent benchmarking studies comparing the practices and performance of public sector organisations, there has been little research on initiatives that involve coordinating multiple benchmarking projects within public sector organisations or report on the practices implemented and results from benchmarking projects. This research will be of interest to centralised authorities wishing to encourage and assist multiple organisations in undertaking benchmarking projects. Design: The study adopts a case study methodology. Data was collected on the coordinating mechanisms and the experiences of the individual organisations over a one-year period. Findings: The findings show successful results (financial and non-financial) across all 13 benchmarking projects thus indicating the success of a coordinated approach to managing multiple projects. The study concluded by recommending a six-stage process for coordinating multiple benchmarking projects. Originality: This research gives new insights into the application and benefits from benchmarking due to the open access the research team had to the ‘Dubai We Learn’ initiative. To the authors’ knowledge the research was unique in being able to report accurately on the outcome of 13 benchmarking projects with all projects using the TRADE benchmarking methodology

Cement dust exposure and acute lung function: A cross shift study

Background: Few studies have been carried out on acute effects of cement dust exposure. This study is conducted to investigate the associations between current "total" dust exposure and acute respiratory symptoms and respiratory function among cement factory workers. Methods: A combined cross-sectional and cross-shift study was conducted in Dire Dawa cement factory in Ethiopia. 40 exposed production workers from the crusher and packing sections and 20 controls from the guards were included. Personal "total" dust was measured in the workers' breathing zone and peak expiratory flow (PEF) was measured for all selected workers before and after the shift. When the day shift ended, the acute respiratory symptoms experienced were scored and recorded on a five-point Likert scale using a modified respiratory symptom score questionnaire. Results: The highest geometric mean dust exposure was found in the crusher section (38.6 mg/m3) followed by the packing section (18.5 mg/m3) and the guards (0.4 mg/m3). The highest prevalence of respiratory symptoms for the high exposed workers was stuffy nose (85%) followed by shortness of breath (47%) and "sneezing" (45%). PEF decreased significantly across the shift in the high exposed group. Multiple linear regression showed a significant negative association between the percentage cross-shift change in PEF and total dust exposure. The number of years of work in high-exposure sections and current smoking were also associated with cross-shift decrease in PEF. Conclusions: Total cement dust exposure was related to acute respiratory symptoms and acute ventilatory effects. Implementing measures to control dust and providing adequate personal respiratory protective equipment for the production workers are highly recommended

Lung function reduction and chronic respiratory symptoms among workers in the cement industry: a follow up study

<p>Abstract</p> <p>Background</p> <p>There are only a few follow-up studies of respiratory function among cement workers. The main aims of this study were to measure total dust exposure, to examine chronic respiratory symptoms and changes in lung function among cement factory workers and controls that were followed for one year.</p> <p>Methods</p> <p>The study was conducted in two cement factories in Ethiopia. Totally, 262 personal measurements of total dust among 105 randomly selected workers were performed. Samples of total dust were collected on 37-mm cellulose acetate filters placed in closed faced Millipore-cassettes. Totally 127 workers; 56 cleaners, 44 cement production workers and 27 controls were randomly selected from two factories and examined for lung function and interviewed for chronic respiratory symptoms in 2009. Of these, 91 workers; 38 cement cleaners (mean age 32 years), 33 cement production workers (36 years) and 20 controls (38 years) were examined with the same measurements in 2010.</p> <p>Results</p> <p>Total geometric mean dust exposure among cleaners was 432 mg/m³. The fraction of samples exceeding the Threshold Limit Value (TLV) of 10 mg/m³for the cleaners varied from 84-97% in the four departments. The levels were considerably lower among the production workers (GM = 8.2 mg/m³), but still 48% exceeded 10 mg/m³.</p> <p>The prevalence of all the chronic respiratory symptoms among both cleaners and production workers was significantly higher than among the controls.</p> <p>Forced Expiratory Volume in one second (FEV₁) and FEV₁/Forced Vital Capacity (FEV₁/FVC) were significantly reduced from 2009 to 2010 among the cleaners (p < 0.002 and p < 0.004, respectively) and production workers (p < 0.05 and p < 0.02, respectively), but not among the controls.</p> <p>Conclusions</p> <p>The high prevalence of chronic respiratory symptoms and reduction in lung function is probably associated with high cement dust exposure. Preventive measures are needed to reduce the dust exposure.</p

CONDUCTING VERIFICATION AND VALIDATION OF MULTI-AGENT SYSTEMS

ABSTRACT Verification and Validation (V&amp;V) is a series of activitie

Achieving performance excellence through benchmarking and organisational learning

In 2015, the Dubai Government Excellence Programme (DGEP) launched the ‘Dubai We Learn’ initiative as a platform to assist government entities to develop an organisational learning culture which would support innovation and a citizen-focussed approach to delivering government services. This initiative would act as a springboard for the government entities to learn new skills and acquire new tools and techniques that would serve them well into the future. The Centre for Organisational Excellence Research, New Zealand was DGEP’s strategic and technical partner for delivering the initiative. The expertise of the centre and the range of tools developed such as the TRADE Benchmarking Methodology and the Best Practice Resource (www.dgep.bpir.com) would be central to supporting this initiative. This book presents a summary of the Excellence Makers Program which was one of the Dubai We Learn programs. The Excellence Makers Program runs on a one year cycle offering the chance for project teams to be guided on how to find and implement best practices in areas of strategic priority. For 2015 to 2016, 13 government entities participated with teams addressing a variety of improvement challenges ranging from the organisationally simple to the technically complex. During the project year, the project teams all had opportunities to visit and learn from leading international organisations in locations as diverse as Australia, Bahrain, China, Ireland, Singapore, South Korea, USA, UK and the UAE. They also had opportunities to share their progress with other teams and at international conferences. The success of the projects and the new abilities of the teams provide a strong basis for future improvement projects in the 13 government entities as well as across the whole of Dubai government. In conclusion, the government entities that participated in the project have shown the commitment and ability to be anchors for the future development of public services in Dubai