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5 results on '"Jafar S"'

1. Semi-empirical approach to characterize thin water film behaviour in relation to droplet splashing in modelling aircraft icing

Author

Alzaili, Jafar S. L. and Hammond, David W.

Subjects
629.132, Thin Water Film Velocity, Water Film Thickness, Corona Breakup, Volume of Fluid Method, Splashing and Re-impingement, Lattice Boltzmann Method, Solidification
Abstract

Modelling the ice accretion in glaze regime for the supercooled large droplets is one of the most challenging problems in the aircraft icing field. The difficulties are related to the presence of the liquid water film on the surface in the glaze regime and also the phenomena associated with SLD conditions, specifically the splashing and re-impingement. The steady improvement of simulation methods and the increasing demand for highly optimised aircraft performance, make it worthwhile to try to get beyond the current level of modelling accuracy. A semi-empirical method has been presented to characterize the thin water film in the icing problem based on both analytical and experimental approaches. The experiments have been performed at the Cranfield icing facilities. Imaging techniques have been used to observe and measure the features of the thin water film in the different conditions. A series of numerical simulations based on an inviscid VOF model have been performed to characterize the splashing process for different water film to droplet size ratios and impact angles. Based on these numerical simulations and the proposed methods to estimate the thin water film thickness, a framework has been presented to model the effects of the splashing in the icing simulation. These effects are the lost mass from the water film due to the splashing and the re-impingement of the ejected droplets. Finally, a new framework to study the solidification process of the thin water film has been explored. This framework is based on the lattice Boltzmann method and the preliminary results showed the capabilities of the method to model the dynamics, thermodynamics and the solidification of the thin water film.

Published
2012

2. Delayed Hemolytic Transfusion Reaction in a Patient with Sickle Cell Disease: Case Report

Author

Omer,Sawsan A, Alaesh,Jafar S, Algadeeb,Kefah B, Omer,Sawsan A, Alaesh,Jafar S, and Algadeeb,Kefah B

Abstract

Sawsan A Omer,1,2 Jafar S Alaesh,1 Kefah B Algadeeb1 1Department of Medicine, King Fahad Hospital Hofuf, Kingdom of Saudi Arabia (KFHH/KSA), Hofuf, Kingdom of Saudi Arabia; 2Faculty of Medicine, University of Gezira, Wad Medani, SudanCorrespondence: Sawsan A OmerDepartment of Internal Medicine, King Fahad Hospital, Hofuf, Eastern Region, Kingdom of Saudi ArabiaTel +966553210343Email sawsanomer63@yahoo.co.ukBackground: Blood transfusion is a key treatment of sickle cell disease (SCD) complications. Delayed hemolytic transfusion reaction (DHTR) is a delayed reaction, that occurs days to weeks following a transfusion, characterized by mild anemia and/or hyperbilirubinemia and is one of the serious complications of blood transfusion. The symptoms of DHTR resemble those of vaso-occlusive crisis secondary to SCD leading to difficulty or delaying in diagnosis of DHTR. DHTR may lead to multiple organ failure and death.Case Report: A 31-year-old female patient with a known case of SCD presented to our ER in King Fahad hospital Hofuf in the Kingdom of Saudi Arabia, with a history of generalized body ache, exertional dyspnoea, headache and easy fatigability for a few days on a background history of episodic hospital admissions for SCD, but she was admitted 3 times over the previous 6 months and received 6 units of packed red blood cells (PRBCs). The last blood transfusion was 18 days earlier. She was sick and her Hb level was 4.5 g/dL with positive Coombs test and positive alloantibodies, diagnosed as DHTR. We treated her with prednisolone tablets 1 mg/kg daily, intravenous immunoglobulins, 0.4 gm/kg daily for 5 days, and rituximab 500 mg IV every week for 4 weeks. Her Hb level raised up to 8.2 g/dL and she was discharged in good condition.Conclusion: Identifying risk factors for DHTR by history and presentation is urgently needed in order to risk stratify the transfusion regimen. It is important to avoid additional transfusions in these patients if possible because these may

Published
2020

5. Environmental Risk Assessments Based on Bone Marrow Cell Kinetic.

Author

OAK RIDGE NATIONAL LAB TN, Jones, Troyce D., Morris, Max D., Hasan, Jafar S., OAK RIDGE NATIONAL LAB TN, Jones, Troyce D., Morris, Max D., and Hasan, Jafar S.

Abstract

Risk of acute mortality from ionizing radiations, leukemia, and cancer are modeled for exposures to X-rays, photons, fission-produced neutrons, and neutrons produced by thermonuclear processes. Risks from protracted exposures are evaluated in terms of sublethal injury to cells, repair of sublethal injury, I-hit cell killing, killing of cells having unrepaired sublethal injury, and radiation-induced cellular repopulation. These cellular effects can be used to equate the protracted exposure to a prompt or pulse exposure of a reference radiation such as through a calculated value for the Equivalent Prompt Dose (EPD). Model coefficients are given for hematopoietic stem cells, marrow stromal cells, and four representative line of human leukemia and lymphoma cells. A user-friendly, menu-driven, personal computer executable file named MarCell (for marrow cell) is included with this report.

Published
1996

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