1,829 research outputs found
Master of Science
thesisU.S. federal regulations pertinent to surface fan installation are concerned with mine safety and give little attention to the aerodynamic design of the installation. As a result, pressure drops has been reported at the installation. Ventilation surveys have shown that these pressure drops could be as high as 40% of fan pressure. The purpose of this study is to identify the sources for such a pressure drop and to reduce it. In recent years, computational fluid dynamics (CFD) software has been successfully used in visualizing the fluid flow for different flow paths (geometries) subject to obstructions. CFD modeling is based on fluid flow principals. They are also applicable to mine ventilation. ANSYS FLUENT, a CFD software, was used as a research tool in this study. A blower and an exhaust system were studied. For the former, using real mine data, the major sources of pressure loss were identified and parametric studies undertaken to minimize those losses. The losses are due to poor installation design with abrupt changes in air velocity and flow direction. Parametric analysis proved that the distance of the fan from any major obstruction is important. Installing the fan at a distance of at least twice the inlet duct diameter reduces the flow separation and formation of eddies. For the exhaust system, it was found that the geometry of the evasée plays an important role in reducing the pressure losses; for instance, a conical evasée recovers the static pressure of the fan better than a rectangular evasée. This is due to the fact that a rectangular evasée is subjected to shock losses. It is also found that the evasée must be of sufficient length so that the air is fully developed before it is discharged into the atmosphere. A proper transition piece between the fan outlet and the evasée is required. This study has certain drawbacks and limitations. Due to limited computation- memory, no mesh-independent and y-plus tests were performed in the simulations. Mesh sizes were kept constant along with enhanced wall treatment which was used for all simulations
Characterisation of cardiosphere derived cells :investigating hypoxic pre-conditioning on pro-angiogenic properties and tracking the cardiac fibroblast component
PhD ThesisCoronary heart disease is still the leading cause of death in the UK, despite significant advances in clinical treatments. Stem cell transplantation has the potential to improve cardiac function and patient outcome, but optimal cell types, cell preparation methods and cell delivery routes are yet to be established.
The heart contains a small population of progenitor cells that, in culture, contribute to spontaneously formed spheroids known as cardiospheres (Csphs). Following further culture, Csphs give rise to cardiosphere derived cells (CDCs). Both Csphs and CDCs show paracrine benefit including neovascularisation in myocardial ischaemia, leading to improvement in heart function. The aims of this project were to use mouse models to (i) investigate the effect of hypoxic preconditioning on the pro-angiogenic potential of CDCs and (ii) characterise the contribution of cardiac fibroblasts (CFs) to CDCs.
I used Col1a2-CreERT;Rosa26-STOP-YFP mice to track YFP-expressing CFs in myocardial tissue and in CDC culture. Co-staining experiments showed only partial overlap of YFP with other CF markers (vimentin and Fsp1) in heart tissue, which may be due to the heterogeneity of CFs and/or incomplete activation of YFP in CFs. I showed that CF-derived cells exist in all stages of CDC culture, and a small subset of these cells also expressed the stem cell markers Sca-1 or cKit, suggesting CF derived cells may contribute to the progenitor cell population.
My results showed that preconditioning CDCs with 3%O2 enhances cell outgrowth from heart explants and promotes expression of stem cell and pro-angiogenic markers. I then assessed the pro-angiogenic potential of CDCs in vivo using a sub-dermal matrigel plug assay and showed that CDCs alone have limited pro-angiogenic potential. However, 3%O2 preconditioning of CDCs significantly enhances this process.
Further research will increase our understanding of CDC-mediated angiogenesis and improve clinical therapies for MI patients
Leading cause of addiction among teenagers of Pakistan and the role of security forces regarding their rehabilitation
Initially cocaine, opium, cannabis and alcohol were used for the purpose of relieving the physical and mental capabilities, and for medicinal and surgical purpose. But the human spirit of innovation must have led to the use of these substances for mood-altering effects and offer an escape from the real and difficult world of existence to a more agreeable world of fantasy. The major purpose of the study is to highlight the origin and development of the drug addiction in the Pakistani Youth and role of security forces in their rehabilitation. The security forces play a major role in the controlling and smuggling of these drugs. These forces also proving helpful in the rehabilitation of addicts and in the awareness program. But due to the presence of some black sheep the number of young addicts is increasing day by day
Using a contingent valuation approach for improved solid waste management facility: evidence from Kuala Lumpur, Malaysia
This study employed contingent valuation method to estimate the willingness to pay (WTP) of the households to improve the waste collection system in Kuala Lumpur, Malaysia. The objective of this study is to evaluate how household WTP changes when recycling and waste separation at source is made mandatory. The methodology consisted of asking people directly about their WTP for an additional waste collection
service charge to cover the costs of a new waste management project. The new waste management project consisted of two versions: version A (recycling and waste separation is mandatory) and version B (recycling and waste separation is not mandatory). The households declined their WTP for version A when they were asked to separate the waste at source although all the facilities would be given to them for waste separation. The result of this study indicates that the households were not conscious about the benefits
of recycling and waste separation. Concerted efforts should be taken to raise environmental consciousness of the households through education and more publicity regarding waste separation, reducing and recycling
Increasing Employee Organizational Commitment by Correlating Goal Setting, Employee Engagement and Optimism at Workplace
The aim of this study is to explore the link among important factors with effect organizational commitment. Secondly this study focuses to make a positive significant relation in setting of goals, engagement of employee and optimistic approach of behavior at work place environment in order to enhance organizational commitment level of employee. The data for that hypothesized model will be collected form individual belongs to from different organizations and research institutions. The results of this study will contribute new improved ways to achieve maximum level of organizational commitment from employees. This study will provide new insight for the field of performance management. Key words: Organizational commitment, Employee engagement, Work place optimism, Enhancing performance, Goal Settin
Prevalence of Gastroesophageal Reflux Disease among Diabetic Patients at Sharif Medical City Hospital, Lahore, Pakistan
Background: Diabetes mellitus has been linked to various gastrointestinal motility disorders, including gastroesophageal reflux disease (GERD).This study aimed to determine the proportion of GERD in patients with diabetes mellitus.Method: This descriptive cross-sectional study was conducted at the medical outpatient department of Sharif Medical City Hospital, Lahore, from October to December, 2020. Patients previously diagnosed with type II diabetes were included using non-probability consecutive sampling, and the GERDQ questionnaire was used to determine the frequency. IBM SPSS statistics version 23 was used for the analysis of data.Results: Of the 273 participants, 183 (67.0%) were male and the mean age was 51.13±12.8 years. The mean duration of diabetes was 6.97±4.76 years and oral hypoglycemic agents were used by 133 (48.7%) participants. Overall, 133 (48.7%) of the participants had GERD with a mean GERDQ score of 10.8(±1.4).Conclusion: Almost half (48.7%) of the participants have GERD; the most common symptom is regurgitation of stomach contents. Awareness should be raised, and early screening should be done to prevent long-term complications.
Online consumer’s acceptance of social networking sites as potential shopping’s guide
The emergence of social media has significantly altered the strategies that companies use to communicate with customers ( Lee, Xiong, & Hu, 2011). As social media moves from “buzz word” status to strategic tool, more practitioners are developing skills related to this online communication technology (Eyrich, Padman, & Sweetser, 2008). With the development of networks, especially electronic commerce’s appearance, consumers enter a new environment of trade, therefore, with the high degree of price dispersion in the online market, for example, customer information, search behaviour also changes (Guan & Cheng, 2009). In fact, with the rapid development of Web 2.0 technologies, such as Ajax and XML, a great number of social networking sites (e.g., Facebook, Renren, MySpace, Kaixin, and LinkedIn) are emerging, which makes mass users interactions easier and more convenient (Yanli, Yi, & Yuli, 2010). These social media tools allow users to search, organize, share, annotate and contribute to contents in a collaborative way. For example, Curtis et al. (2010) found that social media techniques are becoming more abundant as public relations practitioners become mindful of their effectiveness in respect of reaching target audiences, promoting a specific cause, and further developing communication strategies. More than half of America’s teens and young adults send instant messages and use social networking sites, and more than one-third of all Internet users engage in these activities (Correa, Hinsley, & de Zúñiga, 2010)
- …