mohamed antar - Academia.edu (original) (raw)

Papers by mohamed antar

International Journal of Radiation Applications and Instrumentation. Part B. Nuclear Medicine and Biology, 1990

For 3 groups of patients aged 65 years or greater, liver and spleen lengths were measured from ca... more For 3 groups of patients aged 65 years or greater, liver and spleen lengths were measured from calibrated radiocolloid images. Length relationships between liver (L) and spleen (S) were examined in terms of S as a function of L, as well as (S/L) and (L -S) vs S or L. Liver and spleen lengths were the least well correlated in these patients. The S/L ratio vs S produced the most significant correlation in all 3 groups. This suggests a complex but describable relationship between liver and spleen lengths in the overall aging population, and provides a baseline for comparing the effects of various diseases on S and L.

International Journal of Numerical Methods for Heat & Fluid Flow, 2009

... El-Shaarawi, MAI, Ahmad, NT and Kodah, Z. (1990) ''Mixed convection about a... more ... El-Shaarawi, MAI, Ahmad, NT and Kodah, Z. (1990) ''Mixed convection about a rotating sphere in an axial stream'', Numerical Heat Transfer, Part A, Vol. 18, pp. 71-93. El-Shaarawi, MAI, Al-Farayedhi, AA and Antar, MA (1997) ''Boundary-layer Flow about and inside a liquid ...

2013 Fourth International Conference on e-Learning "Best Practices in Management, Design and Development of e-Courses: Standards of Excellence and Creativity", 2013

ABSTRACT Chickering and Gamson have introduced the principles of good practice in teaching. Then,... more ABSTRACT Chickering and Gamson have introduced the principles of good practice in teaching. Then, several attempts to apply those principles in the on-line/distant learning domain of education were reported in the literature. Two types of virtual experiments were performed and reported in this article. The first type is prepared by the instructor to overcome the time, space and extend physical experiment limitation. In addition, it serves as a model for students' teams to carry out the second type. In the second type, students are divided into teams and work in close contact with their peers and the instructor (facilitator). The realization of the seven principles of good practice in teaching and learning is demonstrated for this type. Furthermore, each team member is playing a leader role for a specified period of time and was providing peer evaluation both for his team members and for other teams.

International Journal of Nuclear Medicine and Biology, 1978

2008 11th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, 2008

Fluid flow and mixed (free and forced) convection heat transfer characteristics over a micro-sphe... more Fluid flow and mixed (free and forced) convection heat transfer characteristics over a micro-sphere at moderate to high values of both Grashof and Reynolds numbers are numerically investigated at uniform wall temperature boundary condition. Although this topic is crucial in understanding the basic flow and heat transfer features about a miniature sphere, little attention was drawn into it in the

Journal of Fluids Engineering, 1997

International Journal of Exergy, 2010

ABSTRACT Exergy destruction due to heat transfer across a building block with multiple cavities i... more ABSTRACT Exergy destruction due to heat transfer across a building block with multiple cavities is evaluated. Conduction heat transfer is considered within the solid material whereas both natural convection and Graybody radiation occur simultaneously in the air-filled cavities. The number of cavities was increased keeping the total width unchanged to investigate its effect on the heat transfer rate and exergy destruction. Using more cavities with less width provides better thermal insulation. In addition, it results in less exergy destruction. Exergy destruction and heat transfer rate can be further reduced by changing the cavities layout and the radiation properties of the block cavity surfaces.

International Journal of Energy Research, 2001

ABSTRACT This article presents a simple, straightforward and accurate numerical technique that ca... more ABSTRACT This article presents a simple, straightforward and accurate numerical technique that can be used to predict the steady and transient temperature distributions in an annular fin with uniform cross-section. Both convection and/or thermal radiation ambient conditions are considered in this study. The heat transfer rate and fin efficiency are also calculated. Results are compared with the exact solution for the steady case where excellent agreement was observed for an insulated tip fin and with approximate solutions for the transient case for a non-insulated tip condition. Copyright © 2001 John Wiley & Sons, Ltd.

Clinical Nuclear Medicine, 1990

Energy, 2010

Accurate calculation of the heat transfer rate across building blocks may lead to significant ene... more Accurate calculation of the heat transfer rate across building blocks may lead to significant energy savings. Conjugate heat transfer analysis is carried out numerically to compute the heat transfer rate/R-value as the number/layout of air-filled cavities is changed. Conduction heat transfer in the block material and both natural convection and radiation in the cavity were considered. It is found that increasing the number of cavities keeping the block width unchanged decreases the heat flux significantly. Five cavities can fit the building block under investigation without compromising the strength. Furthermore, changing the surface emissivity can increase the R-value substantially so that no insulation would be needed to fill the spaces. Thermal radiation plays a considerable role in the heat transfer process of this application. Through this study, the heat transfer characteristics and the gains in the R-value were quantified for the basic blocks used in the local market. Furthermore, the gains in the R-value were calculated for different number of cavities, for different cavities layouts for the conjugate contribution of conduction, convection and/or radiation across the building block. Results are useful for designers and manufacturers of building blocks for better energy savings of end users.

Clinical Nuclear Medicine, 1989

Clinical Nuclear Medicine, 1989

Clinical Nuclear Medicine, 1990

Clinical Nuclear Medicine, 1977

Clinical Nuclear Medicine, 1977

Clinical Nuclear Medicine, 1978

To determine the causes and time course of onset of functional asplenia in adults, a four-part in... more To determine the causes and time course of onset of functional asplenia in adults, a four-part investigation was conducted. This consisted of a review of the world's literature, a survey of colleagues, a detailed study of 4,476 consecutive liver-spleen scans in three hospitals, and continued monitoring of 3,500 scans in five hospitals. Based on the findings, a classification was proposed of the causes of functional asplenia. The two major etiologies were circulatory disturbances and effects directly on splenic reticuloendothelial cells. The time course varied from the essentially instantaneous onset of functional asplenia in patients with acute splenic artery obstruction, to a prolonged and gradual onset in those with chronic damage to splenic reticuloendothelial cells. Functional asplenia was found in 0.14% of the adults who had liver-spleen scans for other indications.

Annual Review of Heat Transfer, 2012

Desalination, 2014

ABSTRACT Export Date: 4 January 2015

Applied Thermal Engineering, 2015

Thermodynamic analysis of an HDH system driven by a parabolic trough solar collector was conducte... more Thermodynamic analysis of an HDH system driven by a parabolic trough solar collector was conducted. The first configuration reveals a GOR of 1.5 while the second configuration reveals a GOR of 4.7. Effective heating of the HDH system was obtained through parabolic trough solar collector.

Volume 3: Advanced Composite Materials and Processing; Robotics; Information Management and PLM; Design Engineering, 2012

This paper proposes a method that dynamically improves a statistical model of system degradation ... more This paper proposes a method that dynamically improves a statistical model of system degradation by incorporating uncertainty. The method is illustrated by a case example of fouling, or degradation, in a heat exchanger in a cogeneration desalination plant. The goal of the proposed method is to select the best model from several representative condenser fouling models including linear, falling rate, and asymptotic fouling, and to validate and improve model parameters over the duration of operation. Maximum likelihood estimation (MLE) was applied to obtain a stochastic distribution of condenser fouling. Akaike's Information Criterion (AIC) and the Bayesian Information Criterion (BIC) were then computed at time intervals to assess the accuracy of the MLE results. The degradation model was further evaluated by estimating future prognoses and then crossvalidating with real world fouling data. The results show the accuracy of a prognosis can be improved substantially by continuously updating fouling model parameters. The proposed method is a step toward facilitating prognosis of engineering systems in the early design stages by improving the prediction of future com-

International Journal of Radiation Applications and Instrumentation. Part B. Nuclear Medicine and Biology, 1990

For 3 groups of patients aged 65 years or greater, liver and spleen lengths were measured from ca... more For 3 groups of patients aged 65 years or greater, liver and spleen lengths were measured from calibrated radiocolloid images. Length relationships between liver (L) and spleen (S) were examined in terms of S as a function of L, as well as (S/L) and (L -S) vs S or L. Liver and spleen lengths were the least well correlated in these patients. The S/L ratio vs S produced the most significant correlation in all 3 groups. This suggests a complex but describable relationship between liver and spleen lengths in the overall aging population, and provides a baseline for comparing the effects of various diseases on S and L.

International Journal of Numerical Methods for Heat & Fluid Flow, 2009

... El-Shaarawi, MAI, Ahmad, NT and Kodah, Z. (1990) ''Mixed convection about a... more ... El-Shaarawi, MAI, Ahmad, NT and Kodah, Z. (1990) ''Mixed convection about a rotating sphere in an axial stream'', Numerical Heat Transfer, Part A, Vol. 18, pp. 71-93. El-Shaarawi, MAI, Al-Farayedhi, AA and Antar, MA (1997) ''Boundary-layer Flow about and inside a liquid ...

2013 Fourth International Conference on e-Learning "Best Practices in Management, Design and Development of e-Courses: Standards of Excellence and Creativity", 2013

ABSTRACT Chickering and Gamson have introduced the principles of good practice in teaching. Then,... more ABSTRACT Chickering and Gamson have introduced the principles of good practice in teaching. Then, several attempts to apply those principles in the on-line/distant learning domain of education were reported in the literature. Two types of virtual experiments were performed and reported in this article. The first type is prepared by the instructor to overcome the time, space and extend physical experiment limitation. In addition, it serves as a model for students' teams to carry out the second type. In the second type, students are divided into teams and work in close contact with their peers and the instructor (facilitator). The realization of the seven principles of good practice in teaching and learning is demonstrated for this type. Furthermore, each team member is playing a leader role for a specified period of time and was providing peer evaluation both for his team members and for other teams.

International Journal of Nuclear Medicine and Biology, 1978

2008 11th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, 2008

Fluid flow and mixed (free and forced) convection heat transfer characteristics over a micro-sphe... more Fluid flow and mixed (free and forced) convection heat transfer characteristics over a micro-sphere at moderate to high values of both Grashof and Reynolds numbers are numerically investigated at uniform wall temperature boundary condition. Although this topic is crucial in understanding the basic flow and heat transfer features about a miniature sphere, little attention was drawn into it in the

Journal of Fluids Engineering, 1997

International Journal of Exergy, 2010

ABSTRACT Exergy destruction due to heat transfer across a building block with multiple cavities i... more ABSTRACT Exergy destruction due to heat transfer across a building block with multiple cavities is evaluated. Conduction heat transfer is considered within the solid material whereas both natural convection and Graybody radiation occur simultaneously in the air-filled cavities. The number of cavities was increased keeping the total width unchanged to investigate its effect on the heat transfer rate and exergy destruction. Using more cavities with less width provides better thermal insulation. In addition, it results in less exergy destruction. Exergy destruction and heat transfer rate can be further reduced by changing the cavities layout and the radiation properties of the block cavity surfaces.

International Journal of Energy Research, 2001

ABSTRACT This article presents a simple, straightforward and accurate numerical technique that ca... more ABSTRACT This article presents a simple, straightforward and accurate numerical technique that can be used to predict the steady and transient temperature distributions in an annular fin with uniform cross-section. Both convection and/or thermal radiation ambient conditions are considered in this study. The heat transfer rate and fin efficiency are also calculated. Results are compared with the exact solution for the steady case where excellent agreement was observed for an insulated tip fin and with approximate solutions for the transient case for a non-insulated tip condition. Copyright © 2001 John Wiley & Sons, Ltd.

Clinical Nuclear Medicine, 1990

Energy, 2010

Accurate calculation of the heat transfer rate across building blocks may lead to significant ene... more Accurate calculation of the heat transfer rate across building blocks may lead to significant energy savings. Conjugate heat transfer analysis is carried out numerically to compute the heat transfer rate/R-value as the number/layout of air-filled cavities is changed. Conduction heat transfer in the block material and both natural convection and radiation in the cavity were considered. It is found that increasing the number of cavities keeping the block width unchanged decreases the heat flux significantly. Five cavities can fit the building block under investigation without compromising the strength. Furthermore, changing the surface emissivity can increase the R-value substantially so that no insulation would be needed to fill the spaces. Thermal radiation plays a considerable role in the heat transfer process of this application. Through this study, the heat transfer characteristics and the gains in the R-value were quantified for the basic blocks used in the local market. Furthermore, the gains in the R-value were calculated for different number of cavities, for different cavities layouts for the conjugate contribution of conduction, convection and/or radiation across the building block. Results are useful for designers and manufacturers of building blocks for better energy savings of end users.

Clinical Nuclear Medicine, 1989

Clinical Nuclear Medicine, 1989

Clinical Nuclear Medicine, 1990

Clinical Nuclear Medicine, 1977

Clinical Nuclear Medicine, 1977

Clinical Nuclear Medicine, 1978

To determine the causes and time course of onset of functional asplenia in adults, a four-part in... more To determine the causes and time course of onset of functional asplenia in adults, a four-part investigation was conducted. This consisted of a review of the world's literature, a survey of colleagues, a detailed study of 4,476 consecutive liver-spleen scans in three hospitals, and continued monitoring of 3,500 scans in five hospitals. Based on the findings, a classification was proposed of the causes of functional asplenia. The two major etiologies were circulatory disturbances and effects directly on splenic reticuloendothelial cells. The time course varied from the essentially instantaneous onset of functional asplenia in patients with acute splenic artery obstruction, to a prolonged and gradual onset in those with chronic damage to splenic reticuloendothelial cells. Functional asplenia was found in 0.14% of the adults who had liver-spleen scans for other indications.

Annual Review of Heat Transfer, 2012

Desalination, 2014

ABSTRACT Export Date: 4 January 2015

Applied Thermal Engineering, 2015

Thermodynamic analysis of an HDH system driven by a parabolic trough solar collector was conducte... more Thermodynamic analysis of an HDH system driven by a parabolic trough solar collector was conducted. The first configuration reveals a GOR of 1.5 while the second configuration reveals a GOR of 4.7. Effective heating of the HDH system was obtained through parabolic trough solar collector.

Volume 3: Advanced Composite Materials and Processing; Robotics; Information Management and PLM; Design Engineering, 2012

This paper proposes a method that dynamically improves a statistical model of system degradation ... more This paper proposes a method that dynamically improves a statistical model of system degradation by incorporating uncertainty. The method is illustrated by a case example of fouling, or degradation, in a heat exchanger in a cogeneration desalination plant. The goal of the proposed method is to select the best model from several representative condenser fouling models including linear, falling rate, and asymptotic fouling, and to validate and improve model parameters over the duration of operation. Maximum likelihood estimation (MLE) was applied to obtain a stochastic distribution of condenser fouling. Akaike's Information Criterion (AIC) and the Bayesian Information Criterion (BIC) were then computed at time intervals to assess the accuracy of the MLE results. The degradation model was further evaluated by estimating future prognoses and then crossvalidating with real world fouling data. The results show the accuracy of a prognosis can be improved substantially by continuously updating fouling model parameters. The proposed method is a step toward facilitating prognosis of engineering systems in the early design stages by improving the prediction of future com-