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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.
Md. Sayed UDDIN(Md. Sayed UDDIN ),Md. Atikur RAHAMAN(Md. Atikur RAHAMAN ),Wasib Bin LATIF(Wasib Bin LATIF ) 한국유통과학회 2023 The Journal of Asian Finance, Economics and Busine Vol.10 No.2
Since the banking industry relies so heavily on strong customer-staff interactions, measuring employee job satisfaction has become a critical problem. To achieve benefits for both individuals and organizations, it is crucial to foster and ensure employee job satisfaction. The main objective of this study is to determine the influencing factors of employees’ job satisfaction in commercial banks in Bangladesh. This study focused on some significant factors such as employee empowerment, job security, management support, and attractive compensation in an organization. In terms of research purpose, non-probability convenience sampling has been used, and the study is quantitative in nature. For data collection purposes, an online survey questionnaire was prepared based on previously published articles. The targeted population was the bank employees of commercial banks in Bangladesh where the final sample size was n = 200. For analyzing the collected data, SPSS 26.0 version has been used to test the study model and the proposed hypotheses. This study also shows that employee empowerment, job security, management support, and attractive compensation have positive and significant effects on employees’ job satisfaction at the workplace. Finally, this study has offered some extraordinary directions and implications for future research on commercial bank authorities in Bangladesh.
Separation axioms in (L,M)-fuzzy topology (L,M)-fuzzy convexity spaces
Osama Rashed Sayed,EL-Sayed EL-Sanousy,Yaser Hassanein Ragheb Sayed 원광대학교 기초자연과학연구소 2021 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.21 No.1
In this paper, we dene r-L-fuzzy closed convex sets and r-L-fuzzy closed neighbourhoods in an (L, M)-fuzzy topology (L, M)-fuzzy convexity spaces. Also, r-L-fuzzy neighbourhood separation properties r- L-FNSi were studied where i = f0, 1, 2, 3, 4g. In addition, we also study the invariance or otherwise of these separation properties under subspace and product.
Alleviation of salt stress in Triticum aestivum by biopriming with Phanerochaete chrysosporium
Hanan El-Sayed Dief,El-Sayed A. Hashem,Salwa Fawzan,Ashraf S. A. El-Sayed 한국작물학회 2021 Journal of crop science and biotechnology Vol.24 No.1
Wheat is one of the most important cereals, vital basic crop in Egypt, covering approximately 32.6% of the total winter land. However, sensitivity to abiotic stress especially salinity is one the major current hurdles that reduce the global yield of this crop. Plant biopriming with fungi is the recent technology that might alleviate the salt stress eff ect. Thus, the objective of this work was to examine the eff ect of Triticum aestivum grains biopriming with Phanerochaete chrysosporium on the response of wheat to salt stress. From the physiological and biochemical parameters, biopriming of wheat grains with P. chrysosporium significantly alleviates the salt stress and markedly increases the growth parameters, photosynthetic pigments and osmolytes (soluble sugars, soluble protein and proline) contents. In addition, it alleviates the oxidative damage, as indicated by the lower accumulation of malondealdehyde and increasing the activity of antioxidant enzymes; superoxide dismutase, catalase, and ascorbate peroxidase in wheat seedlings. Results indicate the potential of using P. chrysosporium biopriming for reducing the deteriorating eff ects of salinity.
Sayed Yusoff Syed Hussain,Wee Hoe Tan,Muhammad Zaffwan Idris 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.11
This paper presents a game-based learning study in Malaysia in which a game has been designed for remedial Mathematics students at primary school level. Mathematics is a core subject taught in all primary schools in Malaysia. However, for students who are recognized as weak in Mathematics, teachers use remedial modules supplied by the Ministry of Education in teaching and learning activities. A research study has been initiated to propose digital game-based learning for the remedial students, aiming to enhance the effectiveness of the modules. A prototype game is designed to be playable on tablet computers. The game contains lessons under the title of Whole Numbers: Addition in Year Two syllabus. This paper reveals the concepts and rationale behind the study and the game design. The research plan is also included to justify the ecological validity of the study.
Influence of Fluorine Doping on Hardness and Compressive Stress of the Diamond-Like Carbon Thin Film
Sayed Mohammad Adel Aghili,Raheleh Memarzadeh,Reza Bazargan Lari,Akbar Eshaghi 한국재료학회 2023 한국재료학회지 Vol.33 No.4
This study assessed the influences of fluorine introduced into DLC films on the structural and mechanical properties of the sample. In addition, the effects of the fluorine incorporation on the compressive stress in DLC films were investigated. For this purpose, fluorinated diamond-like carbon (F-DLC) films were deposited on cobalt-chromium-molybdenum substrates using radio-frequency plasma-enhanced chemical vapor. The coatings were examined by Raman scattering (RS), Attenuated total reflectance Fourier transform infrared spectroscopic analysis (ATR-FTIR), and a combination of elastic recoil detection analysis and Rutherford backscattering (ERDA-RBS). Nano-indentation tests were performed to measure hardness. Also, the residual stress of the films was calculated by the Stony equation. The ATR-FTIR analysis revealed that F was present in the amorphous matrix mainly as C-F and C-F2 groups. Based on Raman spectroscopy results, it was determined that F made the DLC films more graphitic. Additionally, it was shown that adding F into the DLC coating resulted in weaker mechanical properties and the F-DLC coating exhibited lower stress than DLC films. These effects were attributed to the replacement of strong C = C by feebler C-F bonds in the F-DLC films. F-doping decreased the hardness of the DLC from 11.5 to 8.8 GPa. In addition, with F addition, the compressive stress of the DLC sample decreased from 1 to 0.7 GPa.
Sayed Zia Mohammadi,Hooshang Hamidian,Zahra Moeinadini 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.6
A high-surface-area activated carbon was prepared by chemical activation of Glycyrrhiza glabra residuewith ZnCl2 as active agent. Then, the adsorption behavior of Pb(II) and Ni(II) ion onto produced activatedcarbon has been studied. The experimental data were fitted to various isotherm models. According toLangmuir model, the maximum adsorption capacity of Pb(II) and Ni(II) ions were found to be 200 and166.7 mg g-1, respectively, at room temperature. Kinetic studies showed the adsorption processfollowed pseudo second-order rate model. High values of intra-particle rate constants calculated showsthe high tendency of activated carbon for removal of Pb(II) and Ni(II) ions.
Sayed Mohsen Hosseini,Mansoureh Sadat Banijamali,Samaneh Koudzari Farahani,Samaneh Bandehali 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.9
Poly (ether sulfone)-(PES) based mixed-matrix nanofiltration (NF) membranes were fabricated by incorporatingcarbon nanofibers (CNFs) through solution casting technique. Scanning optical microscopy (SOM), scanningelectron microscopy (SEM) and surface roughness analysis were carried out in membrane characterization. Wateruptake, contact angle, tensile strength, and porosity measurements, as well as water flux, salt rejection and antifoulingexperiments were used. SEM images showed more porous structure for the blended membranes compared to virginmembrane. Finger-like pores was also observed for the modified membranes. SOM image showed uniform surface forthe prepared membranes relatively. Surface roughness also showed decreasing trend by increase of CNF ratio. Watercontact angle was reduced from 67.8o for pristine membrane to 54.6o for the blended membranes. Salt rejection alsoincreased from 66.49% for bare membrane to 86.4% for the blended membrane containing of 0.1 wt% CNFs. Themembrane porosity, water content, water flux and tensile strength were enhanced by using CNFs into the membranebody. Blended PES-CNFs membranes showed high fouling resistance compared to the virgin membrane. The fluxrecovery ratio was measured up to 79.20% for the modified membranes.
Sayed Javid Royaee,Morteza Sohrabi,Narges Fallah 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.11
The degradation of phenol was investigated in a continuous flow impinging streams system. In the first step, statistical experimental designs were used to optimize the process of phenol degradation in a photo-impinging streams reactor. The more important factors affecting phenol degradation (p<0.05) were screened by a two-level Plackett-Burman design. Four of the latter parameters, namely phenol concentration, catalyst loading, pH and slurry flow rate,were selected for final process optimization, applying central composite design (CCD). The predicted data showed that the maximum removal efficiency of phenol (99%) could be obtained under the optimum operating conditions (phenol concentration=50 mg l−1, catalyst loading=2.1 g l−1, pH 6.2 and slurry flow rate=550ml min−1). These predicted values were then verified by certain validating experiments. A good correlation was observed between the predicted data and those determined by the experimental study. This may confirm the validity of the statistical optimum strategy. Finally,continuous degradation of phenol was performed, and the results indicated a higher efficiency and an increased performance capability of the present reactor in comparison with the conventional processes.