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Ramadan N. Elshaer,Mohamed K. El‑Fawakhry,Ahmed I. Z. Farahat 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6
The effect of quenching after martensitic finish (QAMf) or quenching & partitioning (Q&P) on microstructure evolution,mechanical properties, and strain hardening instability of low and medium carbon hot rolled steels were investigated. Twoheats of low and medium carbon steels were cast in an induction open furnace. The chemical composition of low carbonsteel is 0.16C–0.27Si–1.47Mn–0.02Al while medium carbon steel is 0.49C–0.30Si–0.91Mn–0.03Al. They were hot-rolledat 1200 °C for 30 min followed by air cooling. The microstructure after hot-rolled gives bands of ferrite and pearlite for0.16 wt% low carbon steel. On the other hand, 0.49 wt% medium carbon steel produces coarse pearlite islands surrounded byferrite phase. To enhance mechanical properties, it was necessary to modify the microstructure of low and medium carbonsteels using QAMfor Q&P processes. The resultant matrix of microstructure after QAMfand Q&P processes containedferrite, bainite, lath martensite, and retained austenite for 0.16 wt% low carbon steel, and polygonal ferrite, lath martensite,and retained austenite for 0.49 wt% medium carbon steel, respectively. In low carbon steel, QAMfprocess increased uniformelongation from 6.6 to 13.5% (105% increase) while ultimate tensile strength (UTS) improved slightly from 645 to 692 MPa(7% increase). However, in medium carbon steel, Q&P reduced uniform elongation from 12.4 to 4.8% (61% decrease) whileincreased UTS from 769 to 1242 MPa (61.5% increase). It is worthy to mention that QAMfprocess exhibited strain hardeninginstability zone (7.8% strain before necking) compared to hot-rolled process (0% strain before necking). On the otherhand, Q&P process highly decreased strain hardening instability zone (0.77% strain before necking) compared to hot-rolledprocess (3.4% strain before necking).
Amal G. Ramadan(Amal G. Ramadan ),Ahmed A. M. Yassein(Ahmed A. M. Yassein ),Eissa A. Eissa(Eissa A. Eissa ),Gamal M. Hassan(Gamal M. Hassan ) 한국축산식품학회 2022 Food and Life Vol.2022 No.3
Zinc oxide nanoparticles (ZnO-NPs) are regularly utilized in the food and fertilizers industries. In our investigation, rats received oral administration of ZnO NPs with a particle size of 30±5 nm once daily at doses of 100, 200, 300, 400, and 600 mg/kg for ten weeks in order to assess the genotoxic effect. Impacts on hematological markers, genotoxic impact, and growth were investigated. The findings showed that ZnO-NPs significantly reduced body weight gain, red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit value (HCT), and platelet count (PLT), while increasing white blood cell (WBC), mean capsular volume (MCV), mean capsular hemoglobin (MCH), and mean capsular hemoglobin concentration (MCHC) in the treated rats. Our results for the comet assay and micronuclei test show a dosage-dependent increase in DNA fragmentation, which was supported by an increase in the percentage of DNA that is tailed, the length and intensity of DNA tails, and the tail moment, especially at the dose of 600 mg/kg. According to the findings, the frequency of micronucleated cells has increased.
Smooth neighborhood structures
Ramadan, A.A.,Kim, Y.C.,El-Gayyar, M.M. Korean Institute of Intelligent Systems 2002 한국지능시스템학회논문지 Vol.12 No.2
In this paper, we introduce the notion of smooth neighborhoods in smooth topological spaces and investigate some of their properties. In particular, we can obtain some smooth topologies from a smooth neighborhood system.
Ramadan, A.A.,Abdel-Sattar, M.A.,Kim, Yong-Chan Korean Mathematical Society 2002 대한수학회보 Vol.39 No.4
In this paper, we study some properties of fuzzy interior spaces. Also, we investigate the relations between fuzzy interior spaces and fuzzy topological spaces. In particular, we prove the existence of product fuzzy topological spaces and product fuzzy interior spaces. We investigate the relations between them.
Ramadan, A.A.,El-Dardery, M.,Kim, Y.C. Korean Institute of Intelligent Systems 2002 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.2 No.1
We study some properties of smooth uniform spaces. We investigate the relationship between smooth topological spaces and smooth uniform spaces. In particular, we define a subspace of a smooth uniform space and a product of smooth uniform spaces.
Ramadan Gawad,Vivek Fellner 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.1
Objective: To determine the effect of gut pH and rumen microbial fermentation on glycerol encapsulated in alginate and alginate-chitosan polymers. Methods: Glycerol was encapsulated at 2.5%, 5%, 7.5%, or 10% (w/w) with sodium alginate (A) and alginate-chitosan (AC) polymers. Surface morphology and chemical modifications of the beads were evaluated using scanning electron microscopy and Fourier transform infrared (FTIR) spectra. Encapsulation efficiency was determined at the 5% glycerol inclusion level in two experiments. In experiment 1, 0.5 g of alginate-glycerol (AG) and alginate-chitosan glycerol (ACG) beads were incubated for 2 h at 39°C in pH 2 buffer followed by 24 h in pH 8 buffer to simulate gastric and intestinal conditions, respectively. In experiment 2, 0.5 g of AG and ACG beads were incubated in pH 6 buffer at 39°C for 8 h to simulate rumen conditions. All incubations were replicated four times. Free glycerol content was determined using a spectrophotometer and used to assess loading capacity and encapsulation efficiency. An in vitro experiment with mixed cultures of rumen microbes was conducted to determine effect of encapsulation on microbial fermentation. Data were analyzed according to a complete block design using the MIXED procedure of SAS (SAS Institute, Cary, NC, USA). Results: For AG and ACG, loading capacity and efficiency were 64.7%, 74.7%, 70.3%, and 78.1%, respectively. Based on the FTIR spectra and scanning electron microscopy, ACG treatment demonstrated more intense and stronger ionic bonds. At pH 6, 36.1% and 29.7% of glycerol was released from AG and ACG, respectively. At pH 2 minimal glycerol was released but pH 8 resulted in 95.7% and 93.9% of glycerol released from AG and ACG, respectively. In vitro microbial data show reduced (p<0.05) fermentation of encapsulated glycerol after 24 h of incubation. Conclusion: The AC polymer provided greater protection in acidic pH with a gradual release of intact glycerol when exposed to an alkaline pH.
Ramadan S. Tantawi 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.9
The influence of the initial stress and the Hall current on a two-temperature thermoelastic material is investigated in the framework of the modified Ohm’s law and Green-Naghdi theory. Analytical expressions for the physical quantities are obtained by using the normal mode method and are presented graphically. Finally, the resulting physical quantities are discussed with and without the initial stress and the Hall current. The results of this study have applications in a wide range of physical problems, geophysical applications, and radiation physics.
Investigation of acrylic/boric acid composite gel for neutron attenuation
Ramadan, Wageeh,Sakr, Khaled,Sayed, Magda,Maziad, Nabila,El-Faramawy, Nabil Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.11
The present work was aimed to show the possibility of using hydrogel (acrylic/boric acid) for evaluation of the neutron radiation shielding. The influence of acrylic acid concentration, different gamma doses and relative contents of boric acid were studied. The physical properties and the thermomechanical stability of the studied samples were investigated. The shielding property of the composite for neutron was tested by Pu-Be neutron source (5 Ci) under room temperature. The neutron fluence rates and gamma fluxes were measured using a stilbene organic scintillator. The macroscopic effective removal cross-section Σ<sub>R</sub> (cm<sup>-1</sup>) of fast neutrons and total attenuation coefficient μ (cm<sup>-1</sup>) of gamma rays has been studied experimentally. The transmission parameters, the relaxation length (??) and the half-value layer (HVL) were obtained. The obtained results indicated that the addition of boric acid to acrylic acid tends to increase the macroscopic effective removal cross-section Σ<sub>R</sub> (cm<sup>-1</sup>) to 0.141 compared to 0.094 of ordinary concrete.
ON FUZZY BITOPOLOGICAL SPACES IN ŠOSTAK'S SENSE
Ramadan, A.A.,Abbas, S.E.,El-Latif, A.A. Abd Korean Mathematical Society 2006 대한수학회논문집 Vol.21 No.3
In this paper, we used the supra fuzzy topology which generated from a fuzzy bitopological space [1] to introduce and study the concepts of continuity (resp. openness, closeness) of mapping, separation axioms and compactness for a fuzzy bitopological spaces. Our definition preserve much of the correspondence between concepts of fuzzy bitopological spaces and the associated fuzzy topological spaces.