The turbulent mixing of a two-dimensional jet of foreign gas with a moving air stream

Imperial Users onl

Computational fluid dynamic characterization of carotid bifurcation stenosis in patient-based geometries

Hemodynamic forces play a role in determining endothelial cell (EC) phenotype and influence vascular remodeling. We present a lesion-based computational fluid dynamic (CFD) pilot analysis to understand the complex spatial and temporal hemodynamic changes that prevail in patients with high-grade carotid artery stenosis (CS). High-resolution three-dimensional (3D) rotational angiography datasets were acquired in eight patients, and used to generate computational meshes. CFD analysis was carried out implementing realistic shear-dependent viscosity for blood. The mean wall shear stress (WSS) within the stenosis region was 107 ± 73 dyn/cm2 rapidly followed by direction reversal and lower oscillating values in the recirculation zone at a mean of 19 ± 14 dyn/cm2. WSS vectors exhibited complex dynamic directional and amplitude oscillations not seen in healthy segments, along with time-dependent convergence and divergence strips during the cardiac cycle. The spatial gradient of WSS revealed an elevated average magnitude at the throat of the stenosis of 1425 ± 1012 dyn/cm3. In conclusion, patient-based CFD analysis of CS predicts a complex hemodynamic environment with large spatial WSS variations that occur very rapidly over short distances. Our results improve estimates of the flow changes and forces at the vessel wall in CS and the link between hemodynamic changes and stenosis pathophysiology

Functional and molecular characterization of the vascular endothelial response to fluid shear stress

Thesis (Ph. D.)--Massachusetts Institute of Technology, Whitaker College of Health Sciences and Technology, 1994.Four reprints in pocket following text.Includes bibliographical references (leaves 217-236).by Adel Moussa Malek.Ph.D

The Correlation between Safety Practices in Construction and Occupational Health

Over recent years, safety has become a way of life for construction and industrial workers in the US. A new safety culture has emerged. In fact, the incidence rate for all recordable nonfatal injury and illness for construction workers has decreased from 13.1% in 1992 to 5.4% in 2007 (BLS, 2002)(BLS, 2008). This decline is due to standards set forth by the Occupational Safety and Health Administration (OSHA) and the efforts of owners, contractors, subcontractors and designers (Farooqui, 2008). The benefits of safety programs are widely apparent and become more evident as companies focus on improving these programs. Are there benefits to focusing on occupational health and wellness of the workers? The Occupational Safety and Health Act of 1970 defines occupational safety and health standard as, “a standard which requires conditions, or the adoption or use of one or more practices, means, methods, operations, or processes, reasonably necessary or appropriate to provide safe or healthful employment and places of employment” (OSHA, 2009). OSHA regulations do not delineate between occupational safety and occupational health, therefore legal compliance does not involve promoting the health of workers. Under OSHA incident reporting guidelines, injury and illness are recorded under the same category (OSHA, 2003). The health and safety programs being implemented need to include a wider scope than just preventing injuries and fatalities. The scope of occupational health should include the physical and mental wellness of workers, including illness and disease, as a result of working conditions or situations to which they are exposed, also encompassing the treatment or diagnosis of problems through medical testing and health surveillance. The health and wellness of workers should be equally important as safety to the construction and industrial industries since it can affect the bottom line of companies. An unhealthy worker or work environment, often leads to lost productivity for companies, lost wages for employees and unsafe working conditions. An even greater cost to companies can be long-term costs of workers compensation and litigation. Furthermore, occupational health of workers has an impact on the workers’ wellbeing, state of mind, overall attitude and morale; therefore the safety, quality of work and inevitably the profitability of the company is affected. This paper explores the possible benefits of focusing on the occupational health and wellness of construction and industrial workers as a separate category from safety. Could the development of an international occupational health standard be a useful tool for construction and industrial industries?Key Words: Occupational Health; Safety; Wellness; Health Monitoring; Health Surveillanc

The Role Of Leadership Styles On Staffs Job Satisfaction In Public Organizations

 Job satisfaction is a very important factor among the employees of Public Universities. Job satisfaction is considered an internal principle created by various elements found within a work environment. Due to the influence of various items on job satisfaction, educational organizations should be conscious of implementing the right leadership styles. However, the lack of attention given to this organizational behavior has led to the rise of abnormal reactions among employees. Thus, the current paper focused on the essential role of leadership styles in improving job satisfaction among the employees of Public Universities. Substantial attention should be dedicated to the precise leadership style practiced in an organization. In the same way, specific leadership styles, as external factors, have an important impact on the job satisfaction of employees at Public Universities, because these styles can improve the employees' commitment to the organizations. This initiative involves enhancing satisfaction among employees and finding an effective leadership style, which is one of the main components of improving educational organizations

The Impact of COVID-19 on the Electronic Commerce Users Behavior

The global coronavirus (COVID-19) pandemic has created an incredibly difficult business climate. Businesses are presented with many new challenges as international borders close, brick-and-mortar businesses shut their doors, and people are told to isolate at home. Many companies face temporary or even permanent closure, with staff facing months of financial uncertainty and concerns. Consumer behavior has been forced to immediately change on a massive scale. People in isolation or under lockdown cannot perform their usual routines, because local shops have been forced to close their doors for safety reasons. Concerns about the availability of goods have encouraged panic buying of items in bulk. Financial uncertainty and the prospect of a severe and long-term recession make for a stark backdrop, which has led to an impact on consumer outlook, perceptions, and behaviors. Around the world, businesses that continue to operate seek the best ways to cope with the prevailing trading conditions and the best ways to adapt their strategies. However, no definite recommendation can be given, because the COVID-19 pandemic is unprecedented. Hence, circumstances are changing fluidly on a daily basis. Defining a strategy now is difficult due to limited evidence or precedent to base assumptions on. Possible business and economic outcomes could be gauged by looking at data from countries that first suffered from the effects of COVID-19. Despite no guarantee that other countries will follow the same trajectory, an analysis of these countries can reveal useful patterns and insights. This research attempts to explore the impacts of the extent of COVID-19 on the e- commerce firms in Saudi Arabia, where the five largest e-commerce firms in the Saudi Arabia were chosen in terms of incomes and market value, This research tests that e- commerce raised due to coronavirus

O inferno em Eneida: mito e poesia

O presente artigo objetiva apresentar uma análise gradual da construção do mito do Inferno, através de elementos poéticos e míticos que se convertem em uma perspectiva imagética. No decorrer do artigo foi possível averiguar a complexidade em torno da criação mítica do Inferno, assim como os vários aspectos referentes a poeticidade que os mitos proporcionaram durante a construção do Mito Inferno, na obra Eneida. Assim, este estudo pode ser visto como um estudo complexo de mitos que interagem entre si, formando um mito maior mediante a poeticidade destes engendramentos: o Mito e a Poesia, na peregrinação de Enéias ao Reino dos Mortos