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The effect of Laves phases and nano-precipitates on the electrochemical corrosion resistance of Mg-Al-Ca alloys under alkaline conditions

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journal of Magnesium and Alloys 2024年第6期12卷 2447-2461页

作者： Markus Felten Veronika Chaineux Siyuan Zhang ali Tehranchi Tilmann Hickel Christina Scheu joshua Spille Marta Lipińska-Chwałek joachim Mayer Benjamin Berkels Marcus Hans Imke Greving Silja Flenner Sandra Sefa Daniela Zander Chair of Corrosion and Corrosion Protection RWTH Aachen UniversityAachen 52072 Germany Max-Planck-Institut für Eisenforschung GmbH Düsseldorf 40237 Germany Central Facility for Electron Microscopy RWTH Aachen UniversityAachen 52074 Germany Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons Forschungszentrum Jülich GmbHJülich 52428Germany Mathematical Image and Signal Processing Aachen Institute for Advanced Study in Computational Engineering ScienceRWTH Aachen UniversityAachen 52062 Germany Materials Chemistry RWTH Aachen UniversityAachen 52074 Germany Institute of Materials Physics Helmholtz-Zentrum HereonGeesthacht 21502 Germany

The electrochemical corrosion mechanisms of Mg alloys were extensively studied in previous investigations of different chemical com-positions,modified surface states and various electrolyte ***,recent research focused on the active state of Mg dissolution,leading to unresolved effects of secondary phases adjacent to a stableα-solid solution passive *** present study investigates the fundamental electrochemical corrosion mechanisms of three different Laves phases with varying phase morphologies and phase fractions in the passive state of Mg-Al-Ca *** microstructure was characterized by(transmission-)electron microscopy and synchrotron-based transmission X-ray *** electrochemical corrosion resistance was determined with a standard three-electrode setup and advanced in-situ flow cell measurements.A new electrochemical activity sequence(C15>C36>α-Mg>C14)was obtained,as a result of a stable passive layer formation on theα-solid ***,nm-scale Mg-rich precipitates were identified within the Laves phases,which tend to inhibit the corrosion kinetics.

关键词： Laves phase STEM Magnesium Corrosion Passive layer

The global,prevalence,and risk factors of postoperative fever after percutaneous nephrolithotomy:A systematic review and meta-analysis

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Asian journal of Urology 2024年第2期11卷 253-260页

作者： Reza Falahatkar Siavash Falahatkar Mohammad Amin Khajavi Gaskarei Masoomeh Afzalipoor ali Mojtahedi Neda aligolighasemabadi Ahmad Deilami Samaneh Mirzaei Dahka Mohammad-Hossein Keivanlou alireza jafari Urology Research Center Guilan University of Medical SciencesGuilanRashtIran Department of Surgery University of SaskatchewanSaskatoonCanada Microbiology Department School of MedicineGuilan University of Medical SciencesRashtIran Department of Internal Medicine School of MedicineGuilan University of Medical SiencesRashtIran School of Nursing and Midwifery Guilan University of Medical SciencesGuilanRashtIran

Objective:This study aimed to explore the global,prevalence,and risk factors of fever after percutaneous nephrolithotomy(PCNL)by conducting a systematic review and ***:The high-sensitivity searching was conducted without time limitation until December 30,2020 in Web of Sciences,Scopus,and PubMed based on inclusion and exclusion ***:The prevalence rates of fever and sepsis among patient undergoing PCNL were estimated 9.5%(95%confidence interval[CI]:9.3%-9.7%),and 4.5%(95%CI:4.2%-4.8%),*** tube was used in 9.96%(95%CI:9.94%-9.97%)of *** mean preoperative white blood cells of patients were 6.401×109/L;18.3%and 4.55%of patients were considered as the positive urinary culture and pyuria,*** 20.4%of patients suffered from residual *** odds ratios(ORs)of fever in patients who suffering from diabetes mellitus,hydronephrosis,staghorn stones,and blood transfusion were 4.62(95%CI:2.95-7.26),1.04(95%CI:0.81-1.34),2.57(95%CI:0.93-7.11),and 2.65(95%CI:1.62-4.35),*** who underwent PCNL in prone position were more likely to develop fever(OR:1.23;95%CI:0.75-2.00)than patients in supine ***:The current study showed that patients who suffer from diabetes mellitus,hydronephrosis,staghorn stones,nephrostomy tube or double-j stent,blood transfusion,and also patients who underwent PCNL in prone position surgery are more likely to develop a postoperative fever after PCNL.

关键词： Percutaneous nephrolithotomy Fever Hydronephrosis Diabetes Meta-analysis

Influence of various shapes of nanoparticles on unsteady stagnation-point flow of Cu-H_(2)O nanofluid on a flat surface in a porous medium:A stability analysis

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Chinese Physics B 2022年第4期31卷 404-413页

作者： Astick Banerjee Krishnendu Bhattacharyya Sanat Kumar Mahato ali j.chamkha Department of Mathematics Sidho-Kanho-Birsha UniversityPurulia 723104India Department of Mathematics Institute of ScienceBanaras Hindu UniversityVaranasi 221005India Faculty of Engineering Kuwait College of Science and TechnologyDoha DistrictKuwait

The nanofluid and porous medium together are able to fulfill the requirement of high cooling rate in many engineering ***,here the impact of various shapes of nanoparticles on unsteady stagnation-point flow of Cu-H_(2)O nanofluid on a flat surface in a porous medium is ***,the thermal radiation and viscous dissipation effects are *** problem governing partial differential equations are converted into self-similar coupled ordinary differential equations and those are numerically solved by the shooting *** computed results can reveal many vital findings of practical ***,dual solutions exist for decelerating unsteady flow and for accelerating unsteady and steady flows,the solution is *** presence of nanoparticles affects the existence of dual solution in decelerating unsteady flow only when the medium of the flow is a porous *** different shapes of nanoparticles are not disturbing the dual solution existence range,though it has a considerable impact on thermal conductivity of the *** shapes of nanoparticles act differently to enhance the heat transfer characteristics of the base fluid,i.e.,the water *** the other hand,the existence range of dual solutions becomes wider for a larger permeability parameter related to the porous *** the cooling rate of the heated surface,it rises with the permeability parameter,shape factor(related to various shapes of Cu-nanoparticles),and radiation *** surface drag force becomes stronger with the permeability ***,with growing values of nanoparticle volume fraction,the boundary layer thickness(BLT)increases and the thermal BLT becomes thicker with larger values of shape *** decelerating unsteady flow,the nanofluid velocity rises with permeability parameter in the case of upper branch solution and an opposite trend for the lower branch is *** thermal BLT is thicker with radiation *** to the ex

关键词： Cu-H_(2)O nanofluid various shapes of nanoparticles unsteady stagnation-point flow dual solutions stability analysis

Effects of velocity and thermal wall slip on magnetohydrodynamics(MHD)boundary layer viscous flow and heat transfer of a nanofluid over a non-linearly-stretching sheet:a numerical study

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Propulsion and Power Research 2018年第2期7卷 182-195页

作者： Dodda Ramya R.Srinivasa Raju j.Anand Rao A.j.chamkha Department of Mathematics University College of ScienceOsmania UniversityHyderabad 500007Telangana StateIndia Department of Engineering Mathematics GITAM UniversityHyderabad CampusRudraram 502329Medak(Dt)Telangana StateIndia Mechanical Engineering Department Prince Mohammad Bin Fahd UniversityP.O.Box 1664Al-Khobar 31952Saudi Arabia

In this analysis,the boundary layer viscous flow of nanofluids and heat transfer over a non-linearly-stretching sheet in the presence of a magnetic field is *** and thermal slip conditions are considered instead of no slip conditions at the boundary.A similarity transformation set is used to transform the governing partial differential equations into non-linear ordinary differential *** reduced equations are solved numerically using the Keller box *** influence of the governing parameters on the dimensionless velocity,temperature,nanoparticle concentration as well as the skin friction coefficient,Nusselt number,and local Sherwood number are *** is found that as the velocity slip parameter increases,the velocity profile is decreased and the skin friction and heat transfer decreased while the mass transfer is *** the thermal slip parameter causes decreases in the heat and mass transfer *** results are presented in both graphical and tabular forms.

关键词： Magnetogydrodynamics(MHD) Nanofluid Non-linearly stretching sheet Velocity slip Thermal slip

Chiral quantum heating and cooling with an optically controlled ion

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Light(Science & Applications) 2024年第7期13卷 1393-1400页

作者： jin-Tao Bu jian-Qi Zhang Ge-Yi Ding jia-Chong Li jia-Wei Zhang Bin Wang Wen-Qiang Ding Wen-Fei Yuan Liang Chen Qi Zhong ali Keçebaş Şahin KÖzdemir Fei Zhou Hui jing Mang Feng State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsInnovation Academy of Precision Measurement Science and TechnologyChinese Academy of Sciences430071 WuhanChina. University of the Chinese Academy of Sciences 100049 BeijingChina. Research Center for Quantum Precision Measurement Guangzhou Institute of Industry Technology511458 GuangzhouChina. Department of Engineering Science and Mechanics and Materials Research InstitutePennsylvania State UniversityUniversity ParkState CollegePA 16802USA. Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal University410081 ChangshaChina. Department of Physics Zhejiang Normal University321004 JinhuaChina

Quantum heat engines and refrigerators are open quantum systems,whose dynamics can be well understood using a non-Hermitian formalism.A prominent feature of non-Hermiticity is the existence of exceptional points(EPs),which has no counterpart in closed quantum *** has been shown in classical systems that dynamical encirclement in the vicinity of an EP,whether the loop includes the EP or not,could lead to chiral mode ***,we show that this is valid also for quantum systems when dynamical encircling is performed in the vicinity of their Liouvillian EPs(LEPs),which include the effects of quantum jumps and associated noise—an important quantum feature not present in previous *** demonstrate,using a Paul-trapped ultracold ion,the first chiral quantum heating and refrigeration by dynamically encircling a closed loop in the vicinity of an *** witness the cycling direction to be associated with the chirality and heat release(absorption)of the quantum heat engine(quantum refrigerator).Our experiments have revealed that not only the adiabaticity breakdown but also the Landau–Zener–Stückelberg process play an essential role during dynamic encircling,resulting in chiral thermodynamic *** observations contribute to further understanding of chiral and topological features in non-Hermitian systems and pave a way to exploring the relation between chirality and quantum thermodynamics.

关键词： quantum chiral dynamical

Physical properties and maximum allowable mass-radius relation of complexity-free compact stellar objects within modified f(R,T) gravity formalism

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Chinese Physics C 2024年第7期 276-291页

作者： M.K.jasim S.K.Maurya Abdelghani Errehymy ali Khalid jassim Kottakkaran Sooppy Nisar Abdel-Haleem Abdel-Aty Department of Mathematical and Physical Sciences College of Arts and SciencesUniversity of Nizwa Astrophysics Research Centre School of MathematicsStatistics and Computer ScienceUniversity of KwaZulu-Natal Electrical Engineering Department College of EngineeringMustansiriyah University Department of Mathematics College of Science and Humanities in AlkharjPrince Sattam bin Abdulaziz University Department of Physics College of SciencesUniversity of Bisha

This paper investigates the physical properties and predicted radii of compact stars generated by the Tolman-Ⅳ complexity-free model within the background of modified gravity theory,particularly the f(R,T)-gravity theory,under complexity formalism for a spherically symmetric spacetime proposed by *** [Phys Rev D 97:044010,2018].By solving the resulting set of differential equations,we obtain the explicit forms of the energy-momentum(EM) tensor components,including the density,radial pressure,and tangential *** influence of the parameter χ on various physical properties of the star is thoroughly *** model undergoes a series of rigorous tests to determine its physical *** findings indicate that the model exhibits regularity,stability,and a surface with vanishing *** boundary of this surface is determined by carefully selecting the parameter *** complexity method employed in f(R,T) gravity offers an interesting approach for developing astrophysical models that are consistent with observable events as demonstrated by recent *** this regard,we use observational data from the GW190814 event,detected by the LIGO and Virgo observatories,to investigate the validity of the Tolman-Ⅳ model in f(R,T) *** analysis includes comparing the model's predictions with the observed characteristics of the compact object involved in the *** addition,data from two-millisecond pulsars,PSR j1614-2230 and PSR j0952-0607,are incorporated to further constrain the theoretical ***,we present a diagram depicting the relationship between the total mass and radius of the compact object candidates for different values of X.

关键词：

Genomic Profile of SARS-COV-2 Associated with COVID-19 Outbreaks in N’Djamena, Chad

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Advances in Bioscience and Biotechnology 2024年第7期15卷 432-442页

作者： Mathieu Hota Henry Yandai Fissou Dezoumbe Koutaya Djallaye Djimtoïbaye Mahamat Moussa ali cole Doctorale Sciences Techniques et Environnement Universit de NDjamena NDjamena Tchad Institut de Recherche en Elevage pour le Dveloppement NDjamena Tchad Laboratoire des Grandes pidmies Tropicales du CHU le Bon Samaritain NDjamena Tchad Facult des Sciences de la Sant Humaine (FSSH) Universit de NDjamena NDjamena Tchad

Background: SARS-CoV-2 has circulated worldwide with dramatic consequences. In Chad, we have no data reported of variants. The aim of this study was to identify the SARS-CoV-2 variants that circulated during the epidemic from 2020 to 2021. Methods: This is a cross-sectional, descriptive study carried out between 2020 and 2021. Samples from patients with suspected COVID-19 were tested in five laboratories in N’Djamena. One hundred quality samples of the positives were sequenced in Kinshasa using Oxford nanopore technologies minion and the Protocol Midnight SARS-CoV2. Data were processed using Excel version 16 software. Results: Of the 100 samples sequenced, 77 (77%) produced sequences, 23 (23%) did not. The genomic profiles were wild-type Wuhan and minor mutations (19A, 19B (A), 20A (B.1, B.2), 20B (AV.1), 20D (B.1.1.1 /C.36), 20C), variant of concern Alpha (20I), variant of concern Delta (21A/j), variant of interest Eta (21D), variant of concern Omicron (21K) and unclassified variant under surveillance (B.1.640). Of these variants, the maximums were detected in patients aged 26 - 35 with 30.26% and 25.26% in 36 - 45. However, 24.67% were in travelers and 75.32% in residents, 35.06% in those vaccinated against COVID-19 and 62.33% in non-vaccinates. The estimated case-fatality rate was 2.44% (107/4374). Conclusion: This work has provided preliminary data on COVID-19 and SARS-CoV-2 variants circulating during the 2020-2021 epidemics in Chad.

关键词： COVID-19 SARS-CoV-2 Genomic Profile Variant Chad

Natural Convective Boundary Layer Flow over a Horizontal Plate Embedded in a Porous Medium Saturated with a Nanofluid

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journal of Modern Physics 2011年第2期2卷 62-71页

作者： Rama Subba Reddy Gorla ali chamkha 不详

A boundary layer analysis is presented for the natural convection past a horizontal plate in a porous medium saturated with a nano fluid. Numerical results for friction factor, surface heat transfer rate and mass transfer rate have been presented for parametric variations of the buoyancy ratio parameter Nr, Brownian motion parameter Nb, thermophoresis parameter Nt and Lewis number Le. The dependency of the friction factor, surface heat transfer rate (Nusselt number) and mass transfer rate on these parameters has been discussed.

关键词： Natural Convection Porous Medium Nanofluid

ABMRF:An Ensemble Model for Author Profiling Based on Stylistic Features Using Roman Urdu

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Intelligent Automation & Soft Computing 2024年第2期39卷 301-317页

作者： Aiman Muhammad Arshad Bilal Khan Khalil Khan ali Mustafa Qamar Rehan Ullah Khan Department of Computer Science City University of Science and Information TechnologyPeshawarPakistan Department of Computer Science School of Engineering and Digital SciencesNazarbayev UniversityAstanaKazakhstan Department of Computer Science College of ComputerQassim UniversityBuraydahSaudi Arabia Department of Information Technology College of ComputerQassim UniversityBuraydahSaudi Arabia

This study explores the area of Author Profiling(AP)and its importance in several industries,including forensics,security,marketing,and education.A key component of AP is the extraction of useful information from text,with an emphasis on the writers’ages and *** improve the accuracy of AP tasks,the study develops an ensemble model dubbed ABMRF that combines AdaBoostM1(ABM1)and Random Forest(RF).The work uses an extensive technique that involves textmessage dataset pretreatment,model training,and *** evaluate the effectiveness of several machine learning(ML)algorithms in classifying age and gender,including Composite Hypercube on Random Projection(CHIRP),Decision Trees(j48),Na飗e Bayes(NB),K Nearest Neighbor,AdaboostM1,NB-Updatable,RF,andABMRF,they are *** findings demonstrate thatABMRFregularly beats the competition,with a gender classification accuracy of 71.14%and an age classification accuracy of 54.29%,*** metrics like precision,recall,F-measure,Matthews Correlation Coefficient(MCC),and accuracy support ABMRF’s outstanding performance in age and gender profiling *** study demonstrates the usefulness of ABMRF as an ensemble model for author profiling and highlights its possible uses in marketing,law enforcement,and *** results emphasize the effectiveness of ensemble approaches in enhancing author profiling task accuracy,particularly when it comes to age and gender identification.

关键词： Machine learning author profiling AdaBoostM1 random forest ensemble learning text classification