Experimental Investigation of a Walk-in Refrigerator Performance Using R290 as a Retrofit for R22

A. R. El-Sayed,M. El Morsi,N. A. Mahmoud 대한설비공학회 2018 International Journal Of Air-Conditioning and Refr Vol.26 No.4

An experimental performance study is performed on a refrigeration system equipped with a scroll compressor and tested with R22 using an electronic expansion valve (EEV) as an expansion device and controlled by proportional-integral-derivative (PID) control method. The system is tested at −12∘C, −8∘C, −4∘C, 0∘C and 4∘C evaporator air temperature and 20∘C, 25∘C and 30∘C condenser inlet water temperature at 50 Hz compressor driving frequency and 50Hz evaporator fans driving frequency. R22 reached the set point at all temperatures except −12∘C evaporator temperature with 30∘C condenser temperature due to the severe increase in the compressor discharge temperature that could result in the lubricating oil burnout. Then, the system is retrofitted with a reciprocating compressor especially designed to be used with R290 and tested with R290 at the same evaporator and condenser temperatures using EEV as an expansion device. R290 reached all set points at all evaporator and condenser temperatures. Also, R290 was able to reach all evaporator temperatures at higher condenser temperatures, 35∘C and 40∘C, and this will be discussed in future work. The results show that using R290, the pulldown time decreases by 30.3–71.4%, the ON time ratio decreases by 1–23.6%, the compressor discharge temperature decreases by 46.6–81∘C, the refrigerant mass flow rate decreases by 28.8–50.4%, VRC decreases by 15.2–32.5%, the compressor power consumption decreases by 34.4–44.3% and coefficient of performance (COP) increases by 35–115.5%.

Experimental Performance Analysis of R1234yf in an Air-Conditioning System as Substitute of R134a

Medany M. M.,El Morsi M.,El-Sayed A.R. 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.4

In this work, R1234yf is tested in an air-conditioning system as a proposed alternative to R134a. The system is tested at 30, 35, 40, 45 and 50[Formula: see text]Hz evaporator fan frequency to cool the air entering into the evaporator section at a fixed temperature of 35 ∘ C. The system is charged with 600, 700, 800, 1000 and 1200[Formula: see text]g of each refrigerant. The charge mass of 800 grams gives the best performance for both refrigerants. Also, R1234yf has higher COP, exergetic efficiency, second law efficiency, and lower compressor power consumption. Both refrigerants operate at a moderate range of compressor discharge temperature of 85 ∘ C.

Synthesis of Certain 6-(Arylthio)uracils and Related Derivatives as Potential Antiviral Agents

El-Emam, Ali A.,Massoud, Mohamed A.M.,El-Bendary, Eman R.,El-Sayed, Magda A. Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.7

New series of 6-(arylthio)uracils, 6-(4-substituted-1-piperazinyl)uracils, 2,4,5-trioxo-1H,3H-benzothiopyrano[2,3-d]pyrimidine and 5-aryl-2,4-dioxo-1H,3H-pyrimido[5,4-f]benzo[1,4]thiazepines have been prepared and screened for their in vitro activity against herpes simplex-1 virus (HSV-1) and human immunodeficiency virus-1 (HIV-1). The in vitro cytotoxic activity was also evaluated. The results of biological testing revealed that compound 5b showed marginal activity against HSV-1, while compounds 5b and 5f exhibited marginal activity against HIV-1. The rest of the tested compounds were found devoid of antiviral activity against both HSV-1 and HIV-1.

Anticancer activities of some newly synthesized pyrazole and pyrimidine derivatives

Ashraf M. Mohamed,Weal A. El-Sayed,Musaed A. Alsharari,Husam R. M. Al-Qalawi,Mousa O. Germoush 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.9

A series of pyrazolopyridine and pyridopyrimidinederivatives 2–6 were newly synthesized using3,5-bisarylmethylene-1-methylpiperidone as the startingmaterial. The anticancer activities of the synthesizedcompounds were evaluated using 59 different human tumorcell lines, representing cancers of CNS, ovary, renal,breast, colon, lung, leukemia, and melanoma, prostate aswell as kidney. Some of the tested compounds, especiallythose with a fluorine substituent at the para-position in thephenyl ring and those with a pyridopyrimidine-2-thionewith a free –NH or –SH, exhibited greater in vitro antitumoractivities at low concentrations (log 10 [GI50] =-4.6) against the human tumor cell lines. Additionally,some of the compounds had moderate inhibitory effects onthe growth of the cancer cell lines. The detailed synthesis,spectroscopic data and antitumor properties of the synthesizedcompounds are reported.

A Review of the Potential Replacements of HCFC,HFCs Using Environment-Friendly Refrigerants

A. R. El-Sayed,M. El Morsi,N. A. Mahmoud 대한설비공학회 2018 International Journal Of Air-Conditioning and Refr Vol.26 No.3

The adequate and efficient performance of HVAC systems are signs of luxury and human comfort, and the improvement of their performance has been the target of continuous researches. Choosing the suitable refrigerant is the main parameter in matching the system components, selecting the type of heat exchangers, the compressor, the expansion device and the suitable lubricant. The theoretically ideal refrigerant is the one having zero ozone depletion potential (ODP), low global warming potential (GWP), nontoxic, nonflammable, has appropriate thermodynamic and heat transfer properties and is compatible with any type of lubricating oil. Chlorinated, fluorinated refrigerants, zeotropic and azeotropic mixtures satisfy many requirements, but have high ODP and GWP and are not compatible with all types of oil. Hydrocarbons (HCs) satisfy all the requirements except being highly flammable. This work reviews previous research aiming to find substitutes for the environmentally harmful refrigerants by other environmentally friendly ones and compare their performance in various HVAC appliances.

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.

Enhancement and optimization of gamma radiation shielding by doped nano HgO into nanoscale bentonite

Elhassan A. Allam,Rehab M. El-Sharkawy,Atef El-Taher,E.R. Shaaban,RedaElsaman,E. El Sayed Massoud,Mohamed E. Mahmoud 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.6

In this study, nano-scaled shielding materials were assembled and fabricated by doping different weightpercentages of Nano-mercuric oxide (N-HgO) into Nano-Bentonite (N-Bent) based on using (100-x% NBent þ x% N-HgO, x ¼ 10, 20, 30, and 40 wt %). The fabricated N-HgO/N-Bent nanocomposites werecharacterized by FT-IR, XRD, and SEM and evaluated to evaluate their shielding properties toward gammaradiation by using four different g-ray energies form three point sources; 356 keV from 133Ba, 662 keVfrom 137Cs as well as 1173, and 1332 keV from 60Co. The g-rays mass attenuation coefficients were plottedas a function of the doped N-HgO concentrations into N-HgO/N-Bent nanocomposites. The computedvalues of mass attenuation coefficients (mm), effective atomic number (Zeff) and electron density (Nel) bythe as-prepared samples were found to increase, while the half value layer (HVL) and mean free path(MFP) were identified to decrease upon increasing the N-HgO contents. It was concluded also that theincrease in N-HgO concentration led to a direct increase in the mass attenuation coefficient from 0.10 to0.17 cm2/g at 356 keV and from 0.08 to 0.09 cm2/g at 662 keV. However, a slight increase was observed inthe identified mass attenuation coefficients at (1172 and 1332 keV).

Synthesis of Certain 6-(Arylthio)uracils and Related Derivatives as Potential Antiviral Agents

Ali A. El-Emam*,Mohamed A. M. Massoud,Eman R. El-Bendary,Magda A. El-Sayed 대한화학회 2004 Bulletin of the Korean Chemical Society Vol.25 No.7

Numerical and Experimental Behavior of Two-Story Confined Masonry Structure Subjected to Cyclic Loads

Mosaad El-Diasity,Sayed Salah,Mohamed O.R. El-Hariri,Amr A. Gamal,Tarik S. El-Salakawy 한국콘크리트학회 2024 International Journal of Concrete Structures and M Vol.18 No.1

This research presents the numerical and experimental results of lateral cyclic loading applied on a two-story confined masonry structure utilizing local materials and standards. Two half-scale confined masonry structures were constructed using clay masonry units, confining columns, tie beams, and reinforced concrete slabs. The assemblies were tested up to failure using a displacement controlled loading methodology under vertical self-weight and lateral reversed cyclic loading. The walls of the assemblies have varying perforations (solid / windows / doors) to examine the influence of perforation on in-plane and out-of-plane performance. A strengthened assembly with an exterior layer of ferrocement has been used and this suggested upgrading approach enhanced the lateral resistance of the confined assembly by about (61–95%) while improving ductility and total energy absorbed by 27%. The maximum lateral drift at failure have been decreased to (23–31%), however the corresponding load for the first visible fracture have been raised by (150–175%). Furthermore, total failure has been delayed for the strengthened walls (all sides, particularly the perforated sides). Comparing distorted forms, fracture patterns, and capacity curves of finite element models included in this research yielded excellent agreement.

The Effect of Superplasticizers on Eco-friendly Low-Energy One-Part Alkali-Activated Slag

M. Refaie,Alaa Mohsen,El-Sayed A. R. Nasr,Mohamed Kohail 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.6

One-part alkali-activated materials (OP-AAM) have become a promising binder with low carbon and energy requirements associated with superior mechanical and durability characteristics. This study aims to employ commercial superplasticizers (naphthalene-based “Nb-SP” and polycarboxylate-based “PCb-SP”), as well as laboratory-prepared one (phenol–formaldehyde sulfanilate “PFS-SP”) in enhancing the properties of OP-AAM. The main problem of superplasticizers (SPs) in the AAM is their hydrolysis in the alkaline activator (NaOH) used in the activation reactions. Therefore, the thermo-chemical treatment process was utilized to mitigate the high activator alkalinity by impeding the NaOH in the aluminosilicate precursor matrix. The OP-AAM was fabricated from thermo-chemical treatment powder (TCT-P) resulting from sintering blast furnace slag (GGBFS) with 10 wt% NaOH at 300 and 500 °C. The XRD-pattern showed that NaOH was impeded in the GGBFS via sodium aluminum silicate phase formation after sintering at 500 °C. The results showed that the admixed OP-AAM prepared from TCT-P at 500 °C greatly enhanced the workability and mechanical properties. The PFS-SP proved its efficiency in improving the properties of OP-AAM prepared TCT-P at 300 and 500 °C, referring to its high stability in an alkaline medium. While PCb-SP reinforced the properties of OP-AAM prepared from TCT-P at 500 °C only, proving that PCb-SP promotes high capability in TCT-P-500 as well as in Portland cement.