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Dissolved gas analysis and dissipation f.ctor measurement of.mineral oil-based nanof.uids under thermal and electrical f.ults

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High Voltage 2023年第3期8卷 455-465页

作者： Ahmed Maher Diaa-Eldin A.Mansour Khaled Helal ramadan A.A.abd El Aal Department of.Electrical Engineering Faculty of EngineeringPort-Said UniversityPort-SaidEgypt Department of.Electrical Power Engineering Faculty of EngineeringEgypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityAlexandriaEgypt Department of.Electrical Power and Machines Engineering Faculty of EngineeringTanta UniversityTantaEgypt

Mineral oil is the most f.equent insulating liquid used in oil-immersed transf.rmers f.r electrical insulation and heat ***,oil-based nanof.uids are becoming more popular in scientif.c research as they have proved to have better dielectric and thermal *** applying these nanof.uids into actual transf.rmers,they would be exposed to thermal and electrical ***,The aim of.the authors is to investigate the generation pattern of.dissolved gases in nanof.uids under thermal and electrical f.ults and to assess the applicability of.traditional Dissolved Gas Analysis(DGA)techniques if.oil-based nanof.uids are used in ***-based nanof.uid samples were prepared using a magnetic stirrer and an ultrasonic homogeniser and then subjected to simulated thermal and electrical f.ults in the laboratory using properly sealed test *** types of.metal oxides,Silicon dioxide,Titanium dioxide,and Aluminium oxide nanoparticles,have been used to prepare nanof.uids with 0.02 g/L and 0.04 g/L *** gases released and dissolved into oil due to the simulated f.ults were analysed and compared to traditional mineral oil as a *** dielectric dissipation f.ctor was obtained and analysed f.r all *** to the f.ndings,the presence and concentration of.nanoparticles were shown to inf.uence the amount of.gases *** a result,this research is crucial in guaranteeing that traditional DGA techniques can be employed in transf.rmers that use oil-based nanof.uids.

关键词： electrical thermal dioxide

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Measurements of.natural radionuclides in soil samples f.om Upper Egypt

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Nuclear Science and Techniques 2008年第5期19卷 302-307页

作者： Shaban ramadan Mohamed HARB Khaled SALAHEL DIN abd Elbaset ABBADY Mohamed abd Elleh ALI Rolf.MICHEL Physics Department Faculty of ScienceSouth Valley University Center f.r Radiation Protection and Radioecology Hanover University (ZSR)

This paper presents the results of.natural radioactivity measured f.r the soil of.Qena using gamma-ray spectrometry at ZSR,Hanover University,*** samples of.radioactive concentrations of.^(238)U-series (^(234)Th, ^(214)pb,and^(214)Bi),^(232)Th-series (^(228)Ac,^(212)pb,and ^(208)T1) and ^(40)K were *** objectives were set:(1) activity levels by surf.ce soil sampling at 0～30 cm depth,(2) dose rates of.gamma radiation,radium equivalent,index hazard, and ef.ective dose,and (3) ambient dose rates.

关键词：土壤环境放射能 γ光谱测定法辐射暴露环境剂量

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Agrobacterium-Mediated Transf.rmation of.Rice: Constraints and Possible Solutions

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Rice science 2019年第3期26卷 133-146页

作者： Sulaiman mohammed Azman abd SAMAD Zaidah RAHMAT Department of.Biotechnology and Medical Engineering Faculty of Biosciences and Medical Engineering Universiti Teknologi Malaysia Department of.Biological Sciences Faculty of Science Gombe State University

Genetic transf.rmation of.rice(Oryza sativa L.) by introducing benef.cial traits is now a central research instrument in plant physiology and a practical tool f.r plant improvement. Many approaches are verif.ed f.r stable introduction of.f.reign genes into the plant genome. The review examined the dif.erent constraints that limit the success of.rice genetic transf.rmation via Agrobacterium-mediated approach and suggested possible solutions. Explant identif.cation, gene transf.r technique and construct to tailor the integration, transgene expression without collateral to genetic damage and transf.rmant selection are among the technical challenges af.ecting the rice transf.rmation. Despite the contests, Agrobacteriummediated transf.rmation system has been a better option f.r producing transgenic rice varieties because of.its exact T-DNA processing and simple integration of.low copy-number transgene. This inf.rmation is necessary f.r improving the transf.rmation system f.r recalcitrant rice varieties.

关键词： rice Agrobacterium-mediated transf.rmation tissue culture gene transf.r T-DNA integration

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Could ketamine be the answer to treating treatment-resistant major depressive disorder?

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General Psychiatry 2020年第5期33卷 296-300页

作者： abdullah mohammed ramadan Islam Ahmed Mansour Psychiatry Mansoura University Faculty of MedicineMansouraEgypt

Major depressive disorder(MDD)is a common,serious,debilitating condition af.ecting 350 million people worldwide,which remains to be unsatisf.ctorily treated with 53%of.patients still complaining of.symptoms af.er completing their courses with the correct ***,which was approved by the f.od and Drug Administration in 2019,is a potential treatment option f.r those recalcitrant *** mechanism of.ketamine is not f.lly understood,but as type it is classif.ed as an N-methyl-D-aspartate(NMDA)glutamate receptor antagonist,and can be given intravenously,intranasally and *** is used to treat treatment-resistant depression,depression associated with suicidal ideation,mood and anxiety disorders and depressions associated with either type of.bipolar *** ketamine is considered relatively saf.,several side ef.ects have been reported with the major ones being psychiatric in the f.rm of.worsening mood,anxiety and agitation;psychotomimetic in the f.rm of.dissociation,perceptual disturbance and abnormal sensations;cardiovascular in the f.rm of.increased blood pressure and increased heart rate;and neurological in the f.rm of.headache and *** is still not approved worldwide f.r usage in patients with treatment-resistant MDD,but if.it is approved sometime in the f.ture with relatively f.wer side ef.ects,it is expected to signif.cantly save millions of.dollars spent yearly on patients with treatment-resistant depression and that will lif. this major burden of. the shoulders of.healthcare *** study was designed to measure the ef.ects of.ketamine,an NMDA receptor antagonist,on patients with treatment-resistant MDD and to analyse the concept that makes it dif.erent and relatively saf.r than other major antidepressants like selective serotonin reuptake inhibitors,monoamine oxidase inhibitors and TCAs(tricyclic antidepressants).

关键词： ketamine dosage sensation

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Are climate change and mental health correlated?

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General Psychiatry 2021年第6期34卷 49-57页

作者： abdullah mohammed Hassan ramadan Ahmed G Ataallah Department of.Psychiatry Mansoura University Faculty of MedicineMansouraEgypt

Climate change is one of.the biggest challenges of.our time and is likely to af.ect human beings in substantial ***,researchers started paying more attention to the changes in climate and their subsequent impact on the social,environmental and economic determinants of.health,and the role they play in causing or exacerbating mental health *** ef.ects of.climate change-related events on mental well-being could be classif.ed into direct and indirect *** direct ef.ects of.climate change mostly occur af.er acute weather events and include post-traumatic stress disorder,anxiety,substance abuse disorder,depression and even suicidal *** indirect ef.ects include economic losses,displacement and f.rced migration,competition over scarce resources and collective *** risk f.ctors f.r developing those mental health issues include young age,f.male gender,low socioeconomic status,loss or injury of.a loved one,being a member of.immigrant groups or indigenous people,pre-existing mental illness and inadequate social ***,in some individuals,especially those undisturbed by any directly observable ef.ects of.climate change,abstract awareness and acknowledgement of.the ongoing climate crisis can induce negative emotions that can be intense enough to cause mental health *** strategies should be provided to the af.ected communities to protect their mental health f.om collapse in the f.ce of.climate *** of.the mental health impacts of.climate change should be raised,especially in the high-risk *** and global attention to the climate crisis and its detrimental ef.ects on mental health are *** paper was written with the aim of.trying to understand the currently,scientif.cally proven impact of.climate change-related disasters on mental health and understanding the dif.erent methods of.solving the problem at the corporate level,by trying to decrease greenhouse gas emissions to zero,and at the i

关键词： mostly collective likely

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Permutation-substitution image encryption scheme based on a modif.ed chaotic map in transf.rm domain

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Journal of.Central South University 2017年第9期24卷 2049-2057页

作者： ramadan Noha Ahmed HossamEldin H El-khamy Said E abd El-Samie f.thi E f.culty of.Electronic Engineering Menofia University f.culty of.Engineering Alexandria University

A new chaotic image encryption scheme based on permutation and substitution in the f.urier domain is *** f.urier Transf.rm(f.f.)is used bef.re the encryption scheme to get a large degree of.*** permutation is achieved by Baker map and the substitution by a key-related-to-plain-image algorithm based on the modif.ed Logistic *** of.the Logistic map is developed to increase the space of.the encryption key,and hence increase the *** key of.the encryption algorithm dependents on the plain image,and thus,the cipher image is sensitive to both the initial key and the plain image to resist known-plaintext and chosen plaintext *** key space is large and hence the algorithm can ef.ectively resist brute-f.rce *** proposed scheme is examined using dif.erent perf.rmance evaluation metrics and the results prove that the proposed scheme is highly secure,and it can ef.ectively resist dif.erent attacks.

关键词： Backer map chaotic encryption f.actional f.urier transf.rm (f.f.) modif.ed Logistic map

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Spectral collocation method f.r solving continuous population models f.r single and interacting species by means of.exponential Chebyshev approximation

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International Journal of.Biomathematics 2018年第8期11卷 265-288页

作者： M. A. ramadan M. A. abd El Salam Mathematics Department f.culty of.Science Menoufia University Shebin El-KomEgypt Mathematics Department f.culty of.Science Al-Azhar University Nasr-City Cairo Egypt

In this paper, an ef.icient and accurate method is presented to solve continuous population models f.r single and interacting species using spectral collocation method with exponential Chebyshev (EC) f.nctions. The f.rst problem is a logistic growth model in a population, while the second problem is a prey-predator model: Lotka-Volterra system, the tbird is a simple 2-species Lotka-Volterra competition model, and the f.nal one is a prey-predator model with limit cycle periodic behavior. The high accuracy of.this method is verif.ed through some numerical examples. The obtained numerical results are compared with other methods, showing that the proposed method gives higher accuracy.

关键词： Exponential Chebyshev f.nctions continuous population models spectral collocation method

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Perf.rmance evaluation of.a WDM/OCDM based hybrid optical switch utilizing ef.icient resource allocation

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Chinese Optics Letters 2014年第5期12卷 5-10页

作者： Ahmed Nabih Zaki Rashed abd-Elnaser A. mohammed Osama M.A. Dardeer Electronics and Electrical Communication Engineering Department Faculty of Electronic EngineeringMenofia University

A hybrid optical switch （HOS） with physical layer of.wavelength division multiplexing and optical code division multiplexing （WDM/OCDM） scheme is proposed. An additional f.ature to the HOS than optical cross connect （OXC） is that the controller can process requests f.r both circuit establishment and burst scheduling. In our study, the measurement criteria of.HOS are the blocking probability, probability of.error, and probability of.outage. To simplif. the analysis, no distinction is made between a circuit in progress and a burst in progress. Moreover, a minimum f.t （Minf. resource allocation strategy is applied in order to increase the bandwidth ef.iciency and control the multiplexing interf.rence of.the OCDM. A 2D Markov model f.r the HOS is presented using the Minf.strategy. Numerical results reveal that the code parameters and the resource allocation strategy greatly af.ect the perf.rmance. Certain periority can be achieved by assigning shorter codes to high periority users and longer codes to low periority users. Also, the probability of.error and outage are reduced bv aonling the Minf.strategy.

关键词： WDM Perf.rmance evaluation of.a WDM/OCDM based hybrid optical switch utilizing ef.icient resource allocation

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f.ir subcarrier-power allocation scheme f.r multiuser multicarrier systems

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Journal of.Central South University 2015年第8期22卷 3033-3041页

作者： mohammed abd-Elnaby Germien G.Sedhom Nagy W.Messiha Xu Zhu f.thi E.abd El-Samie f.culty of.Electronic Engineering Menoufia University Deptartment of.Electrical Engineering and Electronics University of Liverpool

The main objective of.multiuser orthogonal f.equency division multiple access(MU-Of.M) is to maximize the total system capacity in wireless communication systems. Thus, the problem in MU-Of.M system is the adaptive allocation of.the resources(subcarriers, bits and power) to dif.erent users subject to several restrictions to maximize the total system capacity. In this work, a proposed subcarrier allocation algorithm was presented to assign the subcarriers with highest channel gain to the users. Af.er the subcarrier allocation, subcarrier gain-based power allocation(SGPA) was employed f.r power and bit loading. The simulation results show that the proposed subcarrier-power allocation scheme can achieve high total system capacity and good f.irness in allocating the resources to the users with slightly high computational complexity compared to the existing subcarrier allocation algorithms.

关键词： multiuser orthogonal f.equency division multiple access (MU-Of.M) subcarrier-allocation power allocation f.irness capacity

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The vitreomacular interf.ce in dif.erent types of.agerelated macular degeneration

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International Journal of.Ophthalmology(English edition) 2017年第2期10卷 246-253页

作者： Mohamed abd ElM onaem El-Hif.awy Hisham Ali Ibrahim Amir ramadan Gomaa Mohamed A Elmasry Ophthalmology Department Alexandria University Faculty of MedicineKhartoum SquareAzaritaAlexandria 21526Egypt

AIM： To evaluate the vitreomacular interf.ce in cases with wet age-related macular degeneration（AMD） and to compare them to eyes with dry AMD and normal ***： This was a cross-sectional comparative study that included 87 eyes with wet AMD,42 eyes with dry AMD and 40 eyes without AMD as a control *** coherence tomography（OCT） examination was perf.rmed f.r all patients to assess the vitreomacular ***： In the wet AMD group,34.5% of.cases had vitreomacular adhesion（VMA）.Only 14.3% of.dry AMD cases and 10% of.control cases had *** was a signif.cant dif.erence between the control group and the wet AMD group（P=0.004） as well as the dry and wet AMD group（P=0.017）.There was also a signif.cant dif.erence between the incidence of.VMA in patients with subretinal choroidal neovascularization（CNV,type 1） and intraretinal CNV（type 2 or type 3）（P=0.020）.CONCLUSION： There is an association between posterior vitreous attachment and *** is also an increased incidence of.VMA with intra-retinal CNV.

关键词： age-related macular degeneration vitreomacular interf.ce optical coherence tomography macula

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