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Numerical Investigation of Rotating stall in Centrifugal Compressor with Vaned and Vaneless Diffuser

Journal of Thermal science 2015年第4期24卷 323-333页

作者： Taher Halawa mohamed Alqaradawi mohamed s.gadala Ibrahim shahin Osama Badr Mechanical Engineering Department UBC-University of British ColumbiaVancouverB.C.Canada Mechanical Engineering Department Cairo University Mechanical & Industrial Engineering Department Qatar University Mechanical Engineering Department Abu Dhabi University Mechanical and Industrial Engineering Department Qatar UniversityDohaQatar Mechanical Engineering Department Benha University Mechanical Engineering Department British University

This study presents a numerical simulation of the stall and surge in a centrifugal compressor and presents a description of the stall development in two different *** first case is for a compressor with vaneless diffuser and the second is for a compressor with vaned diffuser of the vane island *** main aim of this study is to compare the flow characteristics and behavior for the two compressors near the surge operating condition and provide further understanding of the diffuser role when back flow occurs at *** showed that for a location near the diffuser entrance,the amplitude of the static pressure fluctuations for the vaneless diffuser case is higher than that for the vaned diffuser case near surge *** pressure fluctuations in the case of the vaneless diffuser appear with a gradual decrease of the mean pressure value as a part of the surge *** for the case of the vaned diffuser,the pressure drop during surge occurs faster than the case of the vaneless ***,results indicated that during surge in the case of vaneless diffuser,there is a region with low velocity and back flow that appears as a layer connecting all impeller passages near shroud surface and this layer develops in size with *** the other hand,for the case of vaned diffuser during surge,the low velocity regions appear in random locations in some passages and these regions expand with time towards the shroud *** showed that during stall,the impeller passages are exposed to identical impact from stall cells in the case of vaneless diffuser while the stall effect varies from passage to another in the case of the vaned diffuser.

关键词： centrifugal compressors rotating stall surge vaneless diffuser vaned diffuser

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The impact of alpha-fetoprotein(AFP),child-turcotte-pugh(CTP)score and disease staging on the survival of hepatocellular carcinoma(HCC)patients:a retrospective cohort from single oncology center

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Oncology Research 2025年第1期33卷 149-160页

作者： NAssER MULLA YOUsEF KATIB AsIM M.ALMUGHAMsI DUAA s.ALKHAYAT mohamed MOsAAD sAMIR T.ALFOTIH RAWAN ALAOFI Department of Internal Medicine Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of Radiology Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of surgery Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of Endemic and Infectious Diseases Suez Canal UniversityIsmailia41522Egypt King salman bin Abdulaziz Medical City Madinah42311Saudi Arabia Prince Mohammed Bin Abdulaziz Hospital Madinah41511Saudi Arabia

Background:Hepatocellular carcinoma(HCC)is the most common cause of cancer-related death in saudi *** study aimed to investigate the patterns of HCC and the effect of TNM staging,Alfa-fetoprotein(AFP),and Child-Turcotte Pugh(CTP)on patients’overall survival(Os).Methods:A retrospective analysis was conducted on 43 HCC patients at a single oncology center in saudi Arabia from 2015 to *** patients had to fulfill one of the following criteria:(a)a liver lesion reported as definitive HCC on dynamic imaging and/or(b)a biopsy-confirmed ***:The mean patient age of all HCC cases was 66.8 with a male-to-female ratio of 3.3:*** patients were stratified into two groups:viral HCC(n=22,51%)and non-viral HCC(n=21,49%).Among viral-HCC patients,55%were due to HBV and 45%due to *** was diagnosed in 79%of *** and sex did not significantly statistically differ in Os among viral and non-viral HCC patients(p-value>0.05).About 65%of patients had tumor size>5 cm during the diagnosis,with a significant statistical difference in Os(p-value=0.027).AFP was>400 ng/ml in 45%of the *** was a statistically significant difference in the Os in terms of AFP levels(p-value=0.021).A statistically significant difference was also observed between the CTP score and Os(p-value=0.02).CTP class B had the longest *** was the most common treatment provided to HCC patients followed by sorafenib *** was a significant statistical difference in Os among viral and non-viral HCC patients(p-value=0.008).Conclusions:The most common predictors for Os were the underlying cause of HCC,AFP,and tumor *** having non-viral etiology,a tumor size>5 cm,an AFP>400 ng/mL,and a CTP score class C were all negatively associated with Os.

关键词： Hepatocellular carcinoma Pattern Alpha-fetoprotein(AFP) Child-turcotte-pugh Progression free survival

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structural, electronic, and optical studies of chalcogenides stannite Cu2CdsnX4（X=s, se, and Te）: insights from the DFT study

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Optoelectronics Letters 2025年第2期21卷 69-76页

作者： Jamal GUERROUM mohamed AL-HATTAB Lhoucine MOUDOU Khalid RAHMANI Youssef LACHTIOUI Omar BAJJOU Laboratory of Engineering in Chemistry and Physics of Matter Faculty of Sciences and Technics Sultan Moulay Slimane University Ecole Normale supérieure Mohammed V University in Rabat College of Graduate studies University of South Africa

In this paper,we have calculated the structural,electronic,and optical properties of chalcogenide stannite Cu2CdsnX4（X=s,se,Te） *** calculations are based on the density functional theory （DFT） method and are performed using the Cambridge sequential total energy package （CAsTEP） code included in the Biovia Material studio 20 *** optical properties have been studied in a domain that extends energetically from 10 meV to 40 *** results show that Cu2CdsnX4（X=s,se,Te） stannite exhibits absorption in the visible region,the refractive index decreases with increasing energy,and the refractive index values are n=3.2,3.73 and 3.75 for Cu2Cdsns4,Cu2Cdsnse4and Cu2CdsnTe4,*** show also high conductivity,which implies that this material is promising for solar *** results argue in favor of the use of these materials in various potential *** density of state,band structures,and structural properties of Cu2CdsnX4（X=s,se,and Te） stannite are also studied in this work.

关键词： Refractive index

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Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling systems

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structural Durability & Health Monitoring 2025年第1期19卷 77-103页

作者： sabrina Meddah sid Ahmed Tadjer Abdelhakim Idir Kong Fah Tee mohamed Zinelabidine Doghmane Madjid Kidouche Applied Automation Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering Department Mohamed Boudiaf University of M’silaM’sila28000Algeria Department of Civil and Environmental Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building Materials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is *** study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm to the system’s components since they are difﬁcult to be detected and controlled in real *** study investigates the dynamic interactions of these vibrations,speciﬁcally in their high-frequency modes,usingﬁeld data obtained from measurement while ***ﬁndings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem *** obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control ***,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect ***,by exploiting theseﬁndings,the assessment of structural resilience in rotary drilling systems can be ***,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efﬁciency of rotary drilling systems in the petroleum industry.

关键词： Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis ﬁeld data analysis

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small heat shock protein B8:from cell functions to its involvement in diseases and potential therapeutic applications

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Neural Regeneration Research 2025年第10期20卷 2872-2886页

作者： Marta Chierichetti Riccardo Cristofani Valeria Crippa Veronica Ferrari Marta Cozzi Elena Casarotto Paola Pramaggiore Laura Cornaggia Guglielmo Patelli Ali mohamed Margherita Piccolella Mariarita Galbiati Paola Rusmini Barbara Tedesco Angelo Poletti Laboratory of Experimental Biology Dipartimento di Scienze Farmacologiche e Biomolecolari“Rodolfo Paoletti”(DiSFeB)Universitàdegli Studi di MilanoMilanItaly

Heat shock protein family B(small)member 8(HsPB8)is a 22 kDa ubiquitously expressed protein belonging to the family of small heat shock ***8 is involved in various cellular mechanisms mainly related to proteotoxic stress response and in other processes such as inflammation,cell division,and ***8 binds misfolded clients to prevent their aggregation by assisting protein refolding or degradation through chaperone-assisted selective *** line with this function,the pro-degradative activity of HsPB8 has been found protective in several neurodegenerative and neuromuscular diseases characterized by protein misfolding and *** cancer,HsPB8 has a dual role being capable of exerting either a pro-or an anti-tumoral activity depending on the pathways and factors expressed by the model of cancer under ***,HsPB8 exerts a protective function in different diseases by modulating the inflammatory response,which characterizes not only neurodegenerative diseases,but also other chronic or acute conditions affecting the nervous system,such as multiple sclerosis and intracerebellar *** note,HsPB8 modulation may represent a therapeutic approach in other neurological conditions that develop as a secondary consequence of other *** is the case of cognitive impairment related to diabetes mellitus,in which HsPB8 exerts a protective activity by assuring mitochondrial *** review aims to summarize the diverse and multiple functions of HsPB8 in different pathological conditions,focusing on the beneficial effects of its ***-based and alternative therapeutic approaches targeting HsPB8 and its regulated pathways will be discussed,emphasizing how new strategies for cell and tissue-specific delivery represent an avenue to advance in disease treatments.

关键词： aggregation autophagy cancer chaperone chaperone-assisted selective autophagy cognitive impairment HsPB8 neuroinflammation neuromuscular diseases therapy

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series solution of a natural convection flow for a Carreau fluid in a vertical channel with peristalsis

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Journal of Hydrodynamics 2015年第6期27卷 969-979页

作者： ABD ELMABOUD Y. MEKHEIMER Kh.s. mohamed mohamed s. Mathematics Department Faculty of Science and ArtsKhulaisUniversity Of Jeddah Mathematics Department Faculty of ScienceAl-Azhar University(Assiut Branch) Mathematics Department Faculty of ScienceTaif University Hawia Mathematics Department Faculty of ScienceAl-Azhar University

An analysis has been achieved to study the natural convection of a non-Newtonian fluid （namely a Carreau fluid） in a vertical channel with rhythmically contracting walls. The Navier-stokes and the energy equations are reduced to a system of non- linear PDE by using the long wavelength approximation. The optimal homotopy analysis method （OHAM） is introduced to obtain the exact solutions for velocity and temperature fields. The convergence of the obtained OHAM solution is discussed explicitly. Numerical calculations are carried out for the pressure rise and the features of the flow and temperature characteristics are analyzed by plotting graphs and discussed in detail.

关键词： homotopy analysis method (HAM) peristaltic transport carreau fluid heat transfer natural convection flow

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Advanced algorithms for retrieving pileup peaks of digital alpha spectroscopy using antlions and particle swarm optimizations

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Nuclear science and Techniques 2020年第4期31卷 47-68页

作者： mohamed s.El_Tokhy Engineering Department NRCAtomic Energy AuthorityP.No.13759InshasEgypt

Optimization algorithms are applied to resolve the second-order pileup(sOP)issue from high counting rates occurring in digital alpha *** are antlion optimizer(ALO)and particle swarm optimization(PsO)*** optimization algorithms are coupled to one of the three proposed peak finder *** custom time-domain algorithms are proposed for retrieving sOP peaks,namely peak seek,slope tangent,and fast array *** addition,an average combinational algorithm is *** time occurrence of the retrieved peaks is tested for an elimination of illusive *** methods are inaccurate and *** and PsO optimizations are used for the localization of retrieved *** cost values that achieve the best fitness values are ***,the optimum positions of the detected peak heights are *** metrics of the optimized algorithms and their influences on the retrieved peaks parameters are *** among such algorithms are investigated,and the algorithms are inspected in terms of their computational time and average *** peak seek algorithm achieves the lowest average computational error for pulse parameters(amplitude and position).However,the fast array algorithm introduces the largest average error for pulse *** addition,the peak seek algorithm coupled with an ALO or PsO algorithm is observed to realize a better performance in terms of the optimum cost and computational *** contrast,the performance of the peak seek recovery algorithm is improved using the ***,the computational time of the peak optimization using the PsO is much better than that of the ALO *** a final conclusion,the accuracy of the peaks detected by the PsO surpasses that for the peaks detected by the *** implemented peak retrieval algorithms are validated through a comparison with experimental results from previous *** proposed algorithms achieve a notable pr

关键词： Alpha spectrometry instrument second-order pileup signal processing Optimization algorithms

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Optimal and Memristor-Based Control of A Nonlinear Fractional Tumor-Immune Model

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Computers, Materials & Continua 2021年第6期67卷 3463-3486页

作者： Amr M.s.Mahdy Mahmoud Higazy mohamed s.mohamed Department of Mathematics College of ScienceTaif UniversityTaif21944Saudi Arabia Department of Mathematics Faculty of ScienceZagazig UniversityZagazig44519Egypt Department of Physics and Engineering Mathematics Faculty of Electronic engineeringMenoufia UniversityMenouf32952Egypt Department of Mathematics Faculty of ScienceAl-Azher UniversityNasr City11884Egypt

In this article,the reduced differential transform method is introduced to solve the nonlinear fractional model of *** fractional derivatives are described in the Caputo *** solutions derived using this method are easy and very *** model is given by its signal flow ***,a simulation of the system by the simulink of MATLAB is *** disease-free equilibrium and stability of the equilibrium point are *** of a fractional optimal control for the cancer model is *** addition,to control the system,we propose a novel modification of its *** modification is based on converting the model to a memristive one,which is a first time in the literature that such idea is used to control this type of ***,we study the system’s stability via the Lyapunov exponents and Poincare maps before and after *** order differential equations(FDEs)are commonly utilized to model systems that have memory,and exist in several physical phenomena,models in thermoelasticity field,and biological *** have been utilized to model the realistic biphasic decline manner of elastic systems and infection of diseases with a slower rate of *** are more useful than integer-order in modeling sophisticated models that contain physical phenomena.

关键词： RDTM tumor-immune optimal control caputo derivative signal flow simulink disease-free equilibrium stability memristive lyapunov exponents poincare map

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Paraconductivity study in ErBa_2Cu_(3-x)M_xO_(7-δ)(M=Zn, Fe) superconductors

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Chinese Physics B 2013年第11期22卷 562-568页

作者： A.sedky s.B.mohamed Physics Department Faculty of Science King Faisal University Physics Department Faculty of Science Assiut University

We report here the paraconductivity of ErBa2Cu3-xMxO7-δ （M = Zn and Fe） superconductors. The logarithmic plots of excess conductivity Δσ and reduced temperature C reveal two different exponents corresponding to crossover temperature as a result of shifting the order parameter from 2 to 3. The first exponent in the normal field region is close to 1, in which the order parameter dimensionality （OPD） is 2. The second exponent in the critical field region is close to 0.5, in which the OPD is 3. The coherence length, interlayer coupling, interlayer separation and carrier concentration decrease with increasing doping content, and their values for Fe samples are different from those of Zn samples. While anisotropy is increased with increasing doping content, it is generally higher for a Zn sample than that for an Fe sample. We also estimate several physical parameters such as upper critical magnetic fields in the a–b plane and along the c axis （Bab and Bc）, and critical current density J at 0 K. Although Bab and Bc are generally increased with doping content increasing, the value of Bab is found to be twice more than that of Bc. A similar behavior is obtained for J （0 K） and its value is higher in the Fe sample than that in the Zn sample. These results are discussed in terms of oxygen deficiency, localization of carriers, and flux pinning, which are produced by doping.

关键词： ceramics chemical synthesis X-ray diffraction electrical properties transport properties

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Antioxidant Effect of sepia Ink Extract on Extrahepatic Cholestasis Induced by Bile Duct Ligation in Rats

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Biomedical and Environmental sciences 2015年第8期28卷 582-594页

作者： Hanan saleh Amel M soliman Ayman s mohamed mohamed-Assem s Marie Zoology Department Faculty of Science Cairo University

Objective The aim of our study was to assess the complications of hepatic fibrosis associated with bile duct ligation and the potential curative role of sepia ink extract in hepatic damage induced by bile duct ligation. Methods Rattus norvegicus rats were divided into 3 groups: sham-operated group, model rats that underwent common bile duct ligation (BDL), and BDL rats treated orally with sepia ink extract (200 mg/kg body weight) for 7, 14, and 28 d after BDL. Results There was a significant reduction in hepatic enzymes, ALP, GGT, bilirubin levels, and oxidative stress in the BDL group after treatment with sepia ink extract. Collagen deposition reduced after sepia ink extract treatment as compared to BDL groups, suggesting that the liver was repaired. Histopathological examination of liver treated with sepia ink extract showed moderate degeneration in the hepatic architecture and mild degeneration in hepatocytes as compared to BDL groups. Conclusion sepia ink extract provides a curative effect and an antioxidant capacity on BDL rats and could ameliorate the complications of liver cholestasis.

关键词： Bile duct ligation Hepatic fibrosis Oxidative stress Liver collagen percentage Histopathological examination

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