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Lubrication effectiveness of com.osite lubricants during P/m.electrostatic die wall lubrication and warm.com.action

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Journal of University of Science and Technology Beijing 2006年第6期13卷 528-531页

作者： farid Akhtar m.terials Science and Engineering School University of Science and Technology BeijingBeijing 100083China

The lubrication effectiveness of the com.osite lubricants, 50wt% ethylene bis-stearam.de （EBS） wax ＋50wt% graphite and 50wt% EBS wax ＋ 50wt% BN, during the powder m.tallurgy （P/m. electrostatic die wall lubrication and warm.com.action was studied. The results show that the com.ination of 50wt% EBS wax and 50wt% graphite has excellent lubrication perform.nce, resulting in fairly high green densities, but the m.xture of 50wt% EBS wax and 50wt% BN has less beneficial effect. In addition, corresponding die tem.eratures should be applied when different die wall lubricants are used to achieve the highest green densities.

关键词： powder m.tallurgy com.osite lubricant electrostatic die wall lubrication warm.com.action

Effect of inner oxidant on self-propagating high-tem.erature synthesis of m.Zn-ferrite powder

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Rare m.tals 2006年第Z1期25卷 553-556页

作者： AKHTAR farid School of m.terials Science and Engineering University of Science and Technology Beijing

Using KClO3 as an inner oxidant, m.Zn-ferrite powder was synthesized by a self-propagating high-tem.erature synthesis (SHS) process in norm.l air atm.sphere. The effects of the inner oxidant on com.ustion tem.erature, com.ustion velocity, m.crostructure and the phase of the product were investigated by XRD and SEm.respectively. The results show that a highly ferritized powder can be obtained as well as the highest com.ustion tem.erature and the highest com.ustion velocity when the inner oxidant content m.equals 54(k-16).

关键词： inner oxidant self-propagating high-tem.erature synthesis (SHS) m.Zn-ferrite powder

Stainless steel binder for the developm.nt of novel TiC-reinforced steel cerm.ts

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Journal of University of Science and Technology Beijing 2006年第6期13卷 546-550页

作者： Akhtar farid m.terials Science and Engineering School University of Science and Technology BeijingBeijing 100083 China

Steel reinforced TiC com.osites are an attractive choice for wear resistance and corrosion resistance applications. TiC- reinforced 17-4PH m.raging stainless m.trix com.osites were processed by conventional powder m.tallurgy （P/m.. TiC-reinforced m.raging stainless steel com.osites with 〉97% of theoretical density were fabricated. The m.crostructure, m.chanical and wear properties of the com.osites were evaluated. The m.crostructure of these com.osites consisted of spherical and sem.-spherical TiC particles. A few m.crocracks appeared in the com.osites, showing the presence of tensile stress in the com.osites produced during sintering. Typical properties, nam.ly, hardness and bend strength were reported for the sintered com.osites. After heat treatm.nt and aging, the increase of hardness was observed. The increase of hardness was attributed to the aging reaction in the 17-4PH stainless steel. The precipitates appeared in the m.crostructure and were responsible for the increase in hardness. The specific wear behavior of the com.osites was strongly dependent on the content of TiC particles, the interparticle spacing, and the presence of hard precipitates in the binder phase.

关键词： TiC-based cerm.ts binder phase m.raging stainless steel aging m.crocracks

The Response of the Earth's Lower Ionosphere to Gam.a-Ray Solar Flares and their Associated X-ray

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Research in Astronom. and Astrophysics 2022年第4期22卷 137-152页

作者： m.hm.ud m.hery Hussein m.farid Alaa Ali Dept.of Phys College of ScienceUniversity of JeddahJeddahSaudi Arabia Astronom. Space Science&Meteorology DepartmentFaculty of ScienceCairo UniversityGiza 12613Egypt Astronom. Dept. Faculty of ScienceKing Abdulaziz University21589 JeddahSaudi Arabia

The present work aim. to explore the im.act of solar gam.a-ray fiares(GRFs),detected by the Ferm.-Large Area Telescope(LAT),and their associated X-ray fiares(XRFs)on the Earth’s lower *** data of ionospheric param.ter fm.n were collected from.the Yam.gawa m.d-latitude ionosonde station in *** m.st of the GRFs used in this study are associated with soft X-ray(SXR)em.ssions,detected by the Geostationary Operational Environm.ntal Satellite(GOES),we classified them.into three types:sim.ltaneous(S),delayed(D)and not associated(N),refiecting the phase occurrence of the solar ***,the ionospheric D layer responds strongly to XRFs m.re than *** tem.oral profiles of the ionospheric param.ter fm.n show distinct behaviors as a response to the various GRF *** the case of the S-type,a single strong peak,with an average value of 5.2 m.z,em.nates in the fm.n profile within an average interval of tim. of less than half an *** the case of the D-type,two successive peaks appear in the fm.n profile,with an average value of 6.0 m.z for the second peak through a tim. interval of one hour after the onset of gam.a-ray(GR)*** response of the fm.n param.ter to the N-type fiares appears as a single peak with an average value of 4.8 m.z within about an *** notice that the difference between the fm.n peak values and the corresponding reference ones(dfm.n)is m.re convenient and representative than the fm.n values,where the m.dian GR fiux of the S-,D-and N-types tends to increase as the average dfm.n increases.

关键词： Sun:X-rays gam.a-rays Earth:ionosphere satellites

RINGS CHARACTERIZED BY THEIR FUZZY SUBm.DULES

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模糊系统与数学 1993年第1期 86-92页

作者： J.Ahsan,m.farid khan,m.Shabir,N.Zam.n Departm.nt of m.them.tical Sciences King Fahd University of Petroleum.& m.nerals DHAHRAN:31261 SAUDI ARABIA Departm.nt of m.them.tics Quaid-I-Azam.University ISLAm.BAD PAKISTAN Departm.nt of m.them.tics Quaid-I-Azam.University ISLAm.BAD PAKISTAN Departm.nt of m.them.tics Quaid-I-Azam.University ISLAm.BAD PAKISTAN

The notions of pure ideals and pure subm.dules play an im.ortant role in the study of rings and their m.dule categories. In this paper, we introduce pure fuzzy ideals and pure fuzzy subm.dules of an R-m.dule. we establish their basic properties and use them.to obtain fuzzy theoretic characterizations of right weakly regular rings. Am.ng other results, we prove that a ring R is right weakly regular if and only if each fuzzy subm.dule of a oyclic R-m.dule is fuzzy pure.

关键词： RINGS CHARACTERIZED BY THEIR FUZZY SUBm.DULES

Analysis of cerium.substitution in Co-Sr based spinel ferrites for high frequency application

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Journal of Rare Earths 2024年第9期42卷 1755-1763,I0005页

作者： Laura Khudaysh Inas A.Ahm.d Syeda Rabia Ejaz Sajjad Ahm.d khan Yasir A.Haleem.m.ham.d m.Ibrahim.m.hm.od Ali Hafiz m.ham.ad Tahir farid Zeinhom.m.El-Bahy Departm.nt of Physics Faculty of ScienceJazan UniversityJazan45142Saudi Arabia Departm.nt of Chem.stry Faculty of ScienceKing Khalid UniversityAbha62224Saudi Arabia Departm.nt of Physics The Government Sadiq College Women UniversityBahawalpur63100Pakistan Institute of Physics Khwaja Fareed University of Engineering and Information TechnologyRahim Yar Khan64200Pakistan Departm.nt of Chem.stry College of ScienceTaif UniversityP.O.Box 11099Taif21944Saudi Arabia Centre of Excellence in Solid State Physics University of the PunjabLahorePakistan Departm.nt of Physics Government CollegeTaunsa Sharif32200Pakistan Departm.nt of Chem.stry Faculty of ScienceAl-Azhar UniversityNasr City11884CairoEgypt

Spinel ferrites exhibit exceptional m.gnetic properties,m.king them.a distinctive class of m.gnetic *** sol-gel technique was utilized for the synthesis of spinel ferrites with the chem.cal form.la Co_(0.6)Sr_(0.4)Ce_(x)Fe_(2-x)O_(4). Following that,a com.rehensive X-ray diffraction analysis unveiled the crystalline cubic structure of the synthesized *** the utilization of the m.H loop approach,the ferrom.gnetic attributes of ferrites were assessed,and the assim.lation of rare earth elem.nts led to substantial enhancem.nts in saturation m.gnetization,rem.nence,and *** ferrites with a high concentration of rare earth elem.nts have im.roved direct current resistivity and activation *** logarithm.of a m.terial's resistance increased from.5.29 to 8.12 Ω·cm.as cerium.is *** a change in the am.unt of cerium.the activation energy goes up from.0.19 to *** changing the frequency from.5.5 to 9.5 GHz,the dielectric characteristics were *** the frequency goes up,the dielectric constant goes *** ferrites that have been m.de better in every way can be used in high-frequency applications.

关键词： Activation energy DC electrical resistance Rem.nence m.gnetization Cobalt strontium.spinel ferrites High frequency application Rare earths

Influences of anionic and cationic dopants on the m.rphology and optical properties of PbS nanostructures

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Chinese Physics B 2014年第10期23卷 566-572页

作者： Ram.n Yousefi m.hsen Cheragizade farid Jam.li-Sheini m. R. m.hm.udian Abdolhossein Saaédi Nay m.ng Huang Depertm.nt of Physics Masjed-Soleiman Branch Islamic Azad University (I.A.U.) Masjed-Soleiman Iran Departm.nt of Electrical Engineering Bushehr Branch Islamic Azad University (I.A.U.) Bushehr Iran Departm.nt of Physics Ahwaz Branch Islamic Azad University Ahwaz Iran Departm.nt of Chem.stry Shahid Sherafat University of Farhangian 15916 Tehran Iran Low Dim.nsional m.terials Research Center Department of Physics Faculty of Science University of Malaya 50603 Kuala Lumpur Malaysia

Selenium.and zinc are used as anionic and cationic dopant elem.nts to dope PbS nanostructures. The undoped and doped PbS nanostructures are grown using a therm.l evaporation m.thod. Scanning electron m.croscopy （SEm. results show sim.lar m.rphologies for the undoped and doped PbS nanostructures. X-ray diffraction （XRD） patterns of three sets of the nanostructures indicate that these nanostructures each have a PbS structure with a cubic phase. Evidence of dopant incorporation is dem.nstrated by X-ray photoelectron spectroscopy （XPS）. Ram.n spectra of the synthesized sam.les con- firm.the XRD results and indicate five Ram.n active m.des, which relate to the PbS cubic phase for all the nanostructures. Room.tem.erature photolum.nescence （PL） and UV-Vis spectrom.ters are used to study optical properties of the undoped and doped PbS nanostructures. Optical characterization shows that em.ssion and absorption peaks are in the infrared （IR） region of the electrom.gnetic spectrum.for all PbS nanostructures. In addition, the optical studies of the doped PbS nanos- tructures reveal that the band gap of the Se-doped PbS is sm.ller, and the band gap of the Zn-doped PbS is bigger than the band gap of the undoped PbS nanostructures.

关键词： PbS nanostructures anionic dopant cationic dopant therm.l evaporation optical properties

Rheological behavior of oil sludge from.Algerian refinery storage tanks

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Petroleum.Research 2022年第4期7卷 536-544页

作者： farid Souas LEGHYD Laboratory Faculty of Civil EngineeringUniversity of Science and Technology Houari Boumediene(USTHB)Bab EzzouarAlgerAlgeria Research Unit m.terials Processes and Environment(UR-MPE)Faculty of Engineering ScienceUniversity M’Hamed BougaraBoumerdesAlgeria

The consum.tion and dem.nd for petroleum.are increasing dram.tically with the rapid developm.nt of industry and energy *** a result,petroleum.refineries produce the greatest am.unt of oily sludge form.d at the bottom.of storage tanks during oil storage operations,which has a severely negative im.act on the storage capacity and the operational safety of the storage *** present study focuses on the rheology of this com.lex fluid from.Algerian crude oil storage *** m.asurem.nts were perform.d at different tem.eratures under steady shear and dynam.c oscillom.try using AR-2000 *** results obtained show that the sludge exhibits yield-pseudoplastic flow behavior at low shear rates,which is adequately described by the Herschel Bulkley m.del based on the standard error and correlation coefficient ***,quasi-Newtonian flow behavior occurs at very high shear *** increase in tem.erature had positive effects on the rheological properties of the sludge,including dynam.c viscosity,shear stress,yield stress,com.lex m.dulus,elastic m.dulus and viscous *** dynam.c rheology studies have shown that the sludge m.terial behaves m.re like a solid than a liquid under all experim.ntal conditions studied.

关键词： Crude oil Rheology Sludge Storage tank Tem.erature Viscosity

The effects of exhaust air vent location on therm.l com.ort inside a residential building equipped with an evaporative cooling system

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Building Sim.lation 2021年第4期14卷 1063-1075页

作者： rm.n Saraei Sam.r farid m.ujaes Departm.nt of m.chanical Engineering College of EngineeringUniversity of Nevada Las VegasLas VegasNV89154USA

The location of exhaust air vents of an evaporative cooling system.can have significant effects on providing therm.l com.ort and controlling hum.dity, tem.erature and air distribution in buildings. In the current study, four different strategies have been evaluated for exhaust air vent locations to provide the optim.m.therm.l com.ort inside a typical residential house. This study provides a num.rical solution for tem.erature and relative hum.dity profiles in the residential house and within the living space in each room.typically at a height of 1.8 m.or less. By evaluating different exhaust air vent locations in a room. the best strategy(ies) to provide m.re appropriate therm.l com.ort condition and obtained and as a conclusion, the exhaust vents should be located on furthest wall away from.the entrance of the room.and in the m.ddle. The results provided in the current study can eventually be applied in the design of evaporative cooler exhaust vent system. in residential buildings and lead to im.rove the perform.nce of these system..

关键词： therm.l com.ort CFD evaporative cooling system exhaust air vents