Heat transfer characteristics and entropy generation for wing-shaped-tubes with longitudinal external fins in cross-flow

Sayed Ahmed E. Sayed Ahmed,Osama M. Mesalhy,Mohamed A. Abdelatief 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.6

A numerical study is conducted to clarify heat transfer characteristics, effectiveness and entropy generation for a bundle of wingshaped-tubes attached to Longitudinal fins (LF) at downstream side. The air-side Re a ranged from 1.8 x 10 3 to 9.7 x 10 3 . The fin height (h f ) and fin thickness (δ) have been changed as: (2 mm ≤ h f ≤ 12 mm) and (1.5 mm ≤ δ ≤ 3.5 mm). The analysis of entropy generation is based on the principle of minimizing the rate of total entropy generation that includes the generation of entropy due to heat transfer and friction losses. The temperature field around the wing-shaped-tubes with (LF) is predicted using commercial CFD FLUENT 6.3.26 software package. Correlations of Nu a , St a , and Bejan number (Be), as well as the irreversibility distribution ratio (Φ) in terms of Re a and design parameters for the studied bundle are presented. Results indicated that, installing fins with heights from 2 to 12 mm results in an increase in Nu a from 11 to 36% comparing with that of wing-shaped tubes without fins (NOF). The highest and lowest values of effectiveness (ε) at every value of the considered Re a range are occurred at h f = 6 mm and (NOF), respectively. The wing-shaped-tubes heat exchanger with h f = 6 mm has the highest values of (ε), efficiency index (η) and area goodness factor (G a ) and also the lowest values of Φ and hence the best performance comparing with other arrangements. The minimum values of Φ are occurred at h f = 6 mm. (Be) decreases with increasing Re a for all studied h f . The heat transfer irreversibility predominates for (1800 ≤ Re a ≤ 4200) while the opposite is true for (6950 < Re a ≤ 9700). δ has negligible effect on Nu a and heat transfer irreversibility. Comparisons between the experimental and numerical results of the present study and those, previously, obtained for similar available studies showed good agreements.

Synthesis and Pharmacological Screening for Muscle Relaxant, Anticonvulsant, and Sedative Activities of Certain Organic Compounds Produced by Michael Addition

Said , Makarem M.,Ahmed, Amany A. E.,El-Alfy, Abir T. The Pharmaceutical Society of Korea 2004 Archives of Pharmacal Research Vol.27 No.12

Michael addition of certain nucleophiles on ${\alpha}$ , ${\beta}$-unsaturated ketones 1 led to the formation of adducts 2-7 as well as the reaction of arylidene derivatives with secondary amines afforded the amino compounds 9 and 11. Also, dialkylmalonates were treated with ${\alpha}$-cyano cinnamide to afford 13. On the other hand, double Michael cycloaddition of ethylcyanoacetate or tetrachlorophthalic anhydride to the suitable divinylketone were synthesized to produce 15-17. Selected compounds (13 and 6) were screened for muscle relaxant, anticonvulsant, and sedative activities using established pharmacological models. Their activities were compared with that of phenobarbital sodium taken as standard. Compound 6 was the most potent muscle relaxant while compounds 13a and 13c offered the highest anticonvulsant activity. Meanwhile compound 13c showed the highest potentiation of phenobarbital induced sleep in mice.

Genetic Variation of Stem Characters in Wheat and Their Relation to Kernel Weight underDrought and Heat Stresses

Ahmed Sallam,Mervat Hashad,El-Sayed Hamed,Mohamed Omara 한국작물학회 2015 Journal of crop science and biotechnology Vol.18 No.3

The frequency, duration, and severity of heat and drought stresses singly or in combination can be aggravated by climate change. Under these stresses, the stored carbohydrates in stems play an important role in grain filling in wheat (Triticum aestivum L.) post-anthesis. This study examines the genetic variation of stem characters in wheat and their role in supporting grain weight under favorable and drought, combined drought, and heat conditions. Field experiments were conducted with seven spring wheat genotypes along with their F1 and F2 progenies. Stem diameter (SD), stem density (SDN), and stem weight (SW) were measured in 21 F1 (half-diallel analysis) and 12 F2 (3 x4 North Carolina Design II) crosses. Among stem characters, SD was significantly correlated with thousand kernel weight (TKW) and grain yield per spike (GYPS) in all environments in F1 and F2. All characters showed high heritability estimates. For stem characters, the highest heritability was found for SD in both generations. High positive phenotypic and genotypic correlations were found between stem characters and both TKW and GYPS. The correlation between reductions due to stress (%) in stem characters and reduction due to stress in TKW and GYPS confirmed the strong relationships between stem characters and yield attributes in the stressed environments. We conclude that stem characters, especially SD, may play an important role in sustaining grain filling under such conditions. This is possibly due to a greater stem capacity for assimilates storage post-anthesis and subsequent remobilization to the grains.

Economic and Technical Analysis of Cooling System in Gas Turbine

Ahmed El Sayed Hafez,Ko ByungGuk(고병국),Yoon YongBeum(윤용범) 대한전기학회 2020 대한전기학회 학술대회 논문집 Vol.2020 No.10

Extent the student of middle east studies at dankook university to the competencies of oral expression and difficulties which they faced from their perspective

( Ahmed Sayed Mohammed Nogod Allah ) 단국대학교 GCC국가연구소 2014 걸프지역연구 Vol.2 No.1

The aim of this study is to find out how to own the Middle East Studies Department at the University of dankook oral expression competencies and and identify the main difficulties they face from their perspective. The population of the study consisted of all students of the same University'sMiddle East Studies scholar whom picked delegation (40) randomly sampled for this study, the researcher on the closed questionnaire was adopted as an instrument for the collection of data necessary for the study and after measuring the sincerity and consistency, the researcher used a number of statistical methods of processing the data and found the following results: 1. almlmhai competencies got on top of the arithmetic means that students have to measure the skills of oral expression, followed by intellectual and linguistic and finally the voice side 2-double trust students themselves and theirablities is The main reason for feeling hard-guy students oral expression promoting the confidence of students and their yanfshm and the development of the linguistic and cognitive repertoire and diversifying teaching methods are the most important methods of addressing weaknesses incident guy oral expression. The researcher made a number of recommendations: 1.prepairing educational programmes that contribute to the upgrading and improvement of teaching skills of students 2-traning courses for members teaching in order to familiarize them with competencies of oral expression 3-activating language clubs which help student to improve and develop their oral expression competencies.

Centrifugal Impeller Blade Shape Optimization Through Numerical Modeling

Sayed Ahmed Imran Bellary,Abdus Samad 한국유체기계학회 2016 International journal of fluid machinery and syste Vol.9 No.4

Surrogate model based shape optimization methodology to enhance performance of a centrifugal pump has been implemented in this work. Design variables, such as blade number and blade angles defining the pump impeller blade shape were selected and a three-level full factorial design approach was used for efficiency enhancement. A threedimensional simulation using Reynolds-averaged Navier Stokes (RANS) equations for the performance analysis was carried out after designing the geometries of the impellers at the design points. Standard k-ε turbulence model was used for steady incompressible flow simulations. The optimized impeller incurred lower losses by shifting the trailing edge towards the impeller pressure side. It is observed that the surrogates are problem dependent and most accurate surrogate does not deliver the best design always.

Incidence of Listeria in Egyptian Meat and Dairy Samples

Ahmed Abdel-Rhman Ismaiel,Ali El-Sayed Ali,Gamal Enan 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.1

A total of 180 food samples including meat(raw lean beef, frozen lean beef, and frozen chicken) anddairy products (raw milk, Zabady and Kareesh cheese)were analysed for Listeria. Isolates were differentiatedusing morphological, cultural, and biochemical tests and anAPI-Listeria kit. Zabady cheese was completely free ofListeria. The highest incidence rate (13.33%) was in frozenlean beef. Raw lean beef and milk products showed anincidence rate of 6.67%. The lowest incidence rate (3.33%)was in Kareesh cheese and frozen chicken meat samples. L. monocytogenes showed the lowest incidence rate(0.55%), isolated from one frozen lean beef sample. L. ivanovii and L. grayi showed the highest incidence rate(2.22%), isolated from 4 samples. L. innocua and L. seeligeri were positive in 3 samples (1.67%), and L. welshimeri in 2 samples (1.11%). L. monocytogenes and L. ivanovii were positive for virulence factors (hemolyticproperties, and extracellular enzyme activities).

Life Span Extension of Caenorhabditis elegans by Novel Pyridoperimidine Derivative

Ahmed A. R. Sayed,Kamal M. El-Shaieb,Aboul-Fetouh E. Mourad 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.1

Zwitterions formed from the addition of triphenylphosphine to dialky acetylene-dicarboxylates attack the nucleus of both 1H-perimidine (1) and 1H-benzo[d]imidazole (9) to form novel pyrido[1,2,3-cd]perimidine and imidazo[4,5,1-ij]quinoline derivatives in moderate yields (64-72%). The biological activity of the products has been studied. Compound 3a was found to extend life span of wild type Caenorhabditis elegans under standard laboratory conditions. Both heat stress and induced chemical stress resistance of wild type C. elegans were improved in a reverse dose-dependent manner due to 3a treatment. In addition, treatment of worms with compound 3a significantly attenuated the formation of advanced glycation end products in a reverse dose-dependent manner.

Association Assessment among Risk Factors and Breast Cancer in a Low Income Country: Bangladesh

Ahmed, Kawsar,Asaduzzaman, Sayed,Bashar, Mamun Ibn,Hossain, Goljar,Bhuiyan, Touhid Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.17

Background: In the low incoming country Bangladesh, breast cancer is second most common neoplasm and is increasing at an alarming rate among females. Lack of awareness and illiteracy are contributory factors for late presentation and therefore mortality. Purpose: To examine associations of different factors with breast cancer mortality and to raise awareness among the women of society in Bangladesh. Materials and Methods: This descriptive case-control study was conducted on 160 participants from April 2011 till July 2014. Through a valid questionnaire covering personal and family history, data were collected by face to face interview. For analyzing correlations among factors with breast cancer data, binary logistic regression, Pearson's ${\chi}^2$-value, odd ratios and p-value tests were conducted with SPSS version 20. Results: The mean age of the patients was 43.0 ($SD={\pm}11.12$). In ascending order the leading significant factors were hormone therapy (p<0.0000, OR=4.897), abortion (p<0.0001, OR=3.452), early start menarche (p<0.0002, OR=3.500), family history (p<0.0022, OR=3.235), and late menopause (p<0.0093, OR=3.674) with both ${\chi}^2$ test and logistic regression analyses. Non-significant factors were cancer experience, fatty food habits, marital status and taking alcohol. Conclusions: Regarding the investigation of this study, significant and insignificant factor's correlation visualization with breast cancer will be helpful to increase awareness among Bangladeshi women as well as all over the world.

Effectiveness of meta-models for multi-objective optimization of centrifugal impeller

Sayed Ahmed Imran Bellary,Afzal Husain,Abdus Samad 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.12

The major issue of multiple fidelity based analysis and optimization of fluid machinery system depends upon the proper constructionof low fidelity model or meta-model. A low fidelity model uses responses obtained from a high fidelity model, and the meta-model isthen used to produce population of solutions required for evolutionary algorithm for multi-objective optimization. The Pareto-optimalfront which shows functional relationships among the multiple objectives can produce erroneous results if the low fidelity models are notwell-constructed. In the present research, response surface approximation and Kriging meta-models were evaluated for their effectivenessfor the application in the turbomachinery design and optimization. A high fidelity model such as CFD technique along with the metamodelswas used to obtain Pareto-optimal front via multi-objective genetic algorithm. A centrifugal impeller has been considered as casestudy to find relationship between two conflicting objectives, viz., hydraulic efficiency and head. Design variables from the impellergeometry have been chosen and the responses of the objective functions were evaluated through CFD analysis. The fidelity of each metamodelhas been discussed in context of their predictions in entire design space in general and near optimal region in particular. Exploitationof the multiple meta-models enhances the quality of multi-objective optimization and provides the information pertaining to fidelityof optimization model. It was observed that the Kriging meta-model was better suited for this type of problem as it involved less approximationerror in the Pareto-optimal front.