检索结果-南通市图书馆

Journal of Natural Gas Chemistry 2008年第4期17卷 337-343页

作者： ahmed k.aboul-gh.it ahmed E.Awadallah Salah M.El-kossy Abdel-Lateef H.Mahmoud Process Development Division Egyptian Petroleum Research Institute Faculty of Science Department of ChemistryMNF University Ageeba Petroleum Co.

Natural gas conversion to petrochemicals, principally, benzene, naphthalene, toluene, as well as ethylene under non-oxidative conditions was examined in a fixed bed flow reactor at 700 ℃ and gaseous hourly space velocity （ghSV） of 1500 ml·g ^-1·h^-1 at time-on-stream ranging from 5 rain to 4 h using catalysts containing 6.0%Mo/H-ZSM-5 promoted with Pd or Ir metal. The catalysts were characterized by XRD, TPD, and TGA. The addition of Pd or Ir to 6%Mo/H-ZSM-5 catalyst promoted ethylene production but inhibited the cyclization reaction to aromatics owing to the strong interaction between these noble metals and the framework Al species, which were attached to the acid sites during the impregnation process. Coke deposition on the catalysts was found to decrease upon addition of 0.5wt% of Pd or Ir to 6%Mo/H-ZSM-5 catalyst owing to the hydrogenating activity of these metals.

关键词： natural gas methane benzene ethylene molybdenum Pd Ir H-ZSM-5

金属／分子筛催化剂的卤化氢处理对环己烯加氢转化的影响Ⅱ．Re／H-ZSM-5催化剂

在线全文

学校读者我要写书评

暂无评论

催化学报 2008年第2期29卷 113-122页

作者： ahmed k.aboul-gh.it Noha A.k.aboul-gh.it ahmed E.AWADALLAH 埃及石油研究所过程研发部纳赛尔城9540信箱开罗11787埃及

用HCl或HF对Re/H-ZSM-5催化剂进行了后处理,并在50～400℃用连续流动反应器研究了催化剂对环己烯加氢转化反应的影响.与HCl处理相比,HF处理显著提高了催化剂上环己烯加氢生成环己烷以及甲基环戊烯加氢生成甲基环戊烷的催化活性,这主要... 详细信息

用HCl或HF对Re/H-ZSM-5催化剂进行了后处理,并在50～400℃用连续流动反应器研究了催化剂对环己烯加氢转化反应的影响.与HCl处理相比,HF处理显著提高了催化剂上环己烯加氢生成环己烷以及甲基环戊烯加氢生成甲基环戊烷的催化活性,这主要是因为HF处理催化剂具有较高的铼分散度、酸中心数及酸强度.Re/H-ZSM-5(HF)催化剂上最高的酸中心强度使其具有最高的加氢裂化活性及最低的环己烯脱氢生成环己二烯活性.在未处理的Re/H-ZSM-5催化剂上,沉积在分子筛载体孔道和空穴中非骨架Al和Si的量最少,因而对生成芳烃的脱氢反应具有最高活性.卤化氢处理催化剂上二甲苯异构体的相对产量表明:HF处理催化剂上,对二甲苯产量高于间二甲苯;HCl处理催化剂上,间二甲苯和对二甲苯产量基本相当;在未处理的催化剂上,间二甲苯量产量比对二甲苯高.此外,上述所有催化剂上的邻二甲苯产量均约等于对二甲苯与间二甲苯之和.

关键词：铼 ZSM-5分子筛氯化氢处理氟化氢处理环己烯加氢转化

铂和HF掺杂的H-ZSM-5分子筛催化甲苯与甲醇烷基化反应(英文)

在线全文

学校读者我要写书评

暂无评论

催化学报 2010年第10期31卷 1209-1216页

作者： ahmed k. aboul-gh.it Ateyya A. aboul-ENEIN ahmed E. AWADALLAH Salwa A. ghONEIM Eman A. EMAM Process Development Division Egyptian Petroleum Research Institute Department of Petroleum Refining and Chemical Engineering College of Petroleum and Mining Engineering Suez Canal University

Toluene was alkylated with methanol in a flow type reactor at temperatures between 300 and 500 °C using H-ZSM-5 zeolite, 0.2%Pt/H-ZSM-5 and hydrofluorinated 0.2%Pt/H-ZSM-5 with HF concentrations of 1.0%, 2.0%, 3.0%, or 4.0%. Pt primarily enhances toluene conversion, total xylenes production, and p-xylene relative to its thermodynamic equilibrium. As the concentration of HF increases from 1.0% to 3.0%, the catalyst activity increases because of the increase in the number of acid sites and their strength. Additionally, the surface area and Pt dispersion also increases. An advantage of increased HF doping is that the formation of voluminous trimethylbenzene (TMB) byproducts is inhibited. However, at a HF concentration of 4.0%, Al and Si are partially leached and then deposited mostly in the wider catalytic pores. This was determined by evaluating the pore volume distribution and we determined that reactivity inhibition was ob-viously present and was due to diffusion restriction.

关键词： methanol toluene alkylation platinum hydrofluorination shape-selectivity ZSM-5

在线全文

学校读者我要写书评

暂无评论

沸石催化甘蔗渣裂解制备多壁碳纳米管

燃料化学学报 2021年第10期49卷 1421-1434页

作者： aboul-ENEIN Ateyya A AWADALLAH ahmed E EL-DESOUkI Doaa S aboul-gh.it Noha Ak Process Development Division Egyptian Petroleum Research InstituteCairo 11727Egypt EPRI-Nanotechnology Center Egyptian Petroleum Research InstituteCairo 11727Egypt

通过催化热解农业废弃物甘蔗渣(SCB),采用两步工艺生产具有显著应用价值的碳纳米管(CNTs)。主要研究沸石催化剂(HZSM-5、HMOR和HY)、热解温度(450−700℃)和SCB/ZSM-5的比例(3−12)对SCB催化热解的影响,确定最佳工艺参数。随后,将第一步... 详细信息

通过催化热解农业废弃物甘蔗渣(SCB),采用两步工艺生产具有显著应用价值的碳纳米管(CNTs)。主要研究沸石催化剂(HZSM-5、HMOR和HY)、热解温度(450−700℃)和SCB/ZSM-5的比例(3−12)对SCB催化热解的影响,确定最佳工艺参数。随后,将第一步产生富含碳的热解产物用于第二步由Co-Mo/MgO催化生长CNTs。通过简单的两步工艺催化热解SCB生产CNTs。SCB的催化热解在半间歇式反应器(外径=4 cm,长度=90 cm)中进行,CNTs的生长在水平反应器(外径=2.5 cm,长度=100 cm)中进行。两个反应器通过玻璃管(直径0.6 cm,长度12 cm)连接并将热解产物从反应器I转移到反应器II。在半间歇式反应器中放入经过预处理的SCB和沸石催化剂,并以20℃/min加热到反应所需温度。随后,将0.5 g Co-Mo/MgO加入到水平反应器中作为CNTs的生长催化剂。在一个典型的实验中,将2 g沸石催化剂、24 g SCB放入半间歇式反应器,研究了不同种类沸石催化剂在500℃温度条件下对SCB热解的影响。接着,使用HZSM-5研究了不同温度(450−700℃)对SCB热解的影响。最后,研究了不同SCB/ZSM-5投料比例(SCB/ZSM-5=3、6、9、12)对SCB热解的影响。此外,水平反应器中的CNTs生长温度恒定为700℃。通过XRD、TPR和TPD进行催化剂表征。XRD谱图证实了催化剂存在MgO和Co_(3)O_(4),以及以小尺寸颗粒形式存在的CoMoO4和MgMoO4。使用XRD数据根据Scherrer方程计算45%Co-5%Mo/MgO催化剂的平均晶粒尺寸为25.8 nm。TPR分析表明,Co-Mo/MgO催化剂是由未反应的Co_(3)O_(4)以及混合氧化物组成。使用XRD数据,计算得到HZSM-5、HMOR和HY的平均晶粒尺寸分别为43、41和51 nm。NH3-TPD分析表明沸石催化剂存在大量的酸性位点。催化热解SCB结果表明,由HY和HZSM-5催化剂在500℃得到的挥发性产品(生物油和气体)的总收率值分别为34.4%和32.8%,而使用HMOR产生的这些挥发性产品的收率值最低(28.8%)。用HZSM-5催化热解SCB获得了最高的炭产量(23.1%)。然而,使用HMOR和HY热解催化剂产生的炭产量值较低,分别为15.8%和9.8%。使用TEM表征通过两步法生产的碳纳米管,并且测量了CNTs的外径。数据显示,用HZSM-5进行SCB热解产生了直径分布范围较宽的CNTs(10−56 nm),而用HMOR和HY热解催化剂则分别获得了直径较窄的CNTs(13−44 nm,12−28 nm)。拉曼光谱分析表明,使用HZSM-5作为SCB热解的催化剂可以生产最优的CNTs。研究了不同热解温度对CNTs产量的影响。结果显示,将热解温度从450℃提高到500℃,炭产率值从6.7%达到最佳值23.1%,接着增加温度至700℃,炭产量下降至16.7%。随后对不同温度下催化热解形成的炭产品进行TEM表征,结果显示,随着温度的升高炭产品中CNTs的比例下降,CNTs的直径范围变窄。拉曼光谱分析结果表明,在500和700℃形成的CNMs具有最少的缺陷。研究了投料比例对炭产品产量的影响,结果表明,SCB/ZSM-5的比例从3提高到12,生物油和气体的总产量从36.4%下降到32.8%,而生物炭的产量分别从63.6%增加到67.2%。根据催化剂的质量计算得到炭产量的最佳值是使用SCB/ZSM-5比例为6。使用TEM表征不同投料比例生产的炭产品,分析表征结果可得SCB/ZSM-5的比例为6,是形成具有良好质量的致密CNTs的最佳选择。并且不同投料比例的拉曼光谱显示,SCB/ZSM-5比例为6可以生产最优的CNTs。沸石类型(HZSM-5、HMOR和HY)、热解温度(450−700℃)和SCB/ZSM-5比例(3−12)影响CNTs和热解产物(气体、生物油和生物炭)的产量。实验结果表明,获得最高CNTs产量的条件为:热解温度为500℃、SCB/ZSM-5比例为6;获得最高生物油和气体总产量(40%)的条件为:热解温度为700℃、SCB/ZSM-5比例为12。TEM分析表明,使用HZSM-5催化剂在热解温度450℃只生成竹节状碳纳米管(BCNTs),而CNTs和碳纳米洋葱(CNO)是在较高温度热解温度(500−700℃)下产生的。使用SCB/ZSM-5的比例为6时,生成CNTs的直径分布范围最大(7−76 nm)。拉曼光谱分析表明,使用SCB/ZSM-5的比例为6时,形成的CNTs最优。该研究显示,在半间歇式反应器中催化热解SCB是生产CNTs的有效技术,通过对工艺和反应器的优化可以达到更好的效果。

关键词：碳纳米管 Co-Mo/MgO 热解甘蔗渣 ZSM-5沸石

Effect of energy content of the nitraminic plastic bonded explosives on their performance and sensitivity characteristics

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2019年第4期15卷 488-494页

作者： Svatopluk Zeman ahmed k. Hussein Marcela Jungova ahmed Elbeih Institute of Enegetic Materials Faculty of Chemical Technology University of Pardubice CZ-532 10 Pardubice Czechia Military Technical College Kobry Elkobbah Cairo Egypt

Information about the forty nine nitraminic plastic bonded explosives(PBXs)and different nitramines were *** of these PBXs are nitramines 1,3,5-trinitro-1,3,5-triazinane(RDX)and β-1,3,5,7-tetranitro-1,3,5-tetrazocane(β-HMX),cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole(bicyclo-HMX,BCHMX)and e-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(e-HNIW,CL-20)which are bonded by polyfluoro-elastomers,polydimethyl-siloxane,poly-glycidyl azide,polyisobutylene,polystyrene-butadiene,poly-acrylonitrile-butadiene and hydroxyl-terminated polybutadiene in addition to a melt cast compositions based on 2,4,*** thirty two of these PBXs the relationships are specified and analyzed between heats of their combustion and relative explosive strengths;by means of these relationships it might be possible to estimate,which groupings in the macromolecule of binder could be liable to their primary fission in the PBXs ***,for forty two of these explosives,the relationships are described and analyzed between their enthalpies of formation and impact sensitivities;here is especially attention paid to PBXs filled by *** rate constants from Vacuum Stability Test(VST)of four nitramines and twenty PBXs are introduced into relationships with their enthalpies of *** to all the mentioned cases,increasing of energy content of the studied explosives leads to increase of the relative explosive strength or initiation reactivity,*** with the opposite trend,the outputs of VST are for BCHMX,where in PBXs are matrices with the esteric plasticizers or the energetic poly-glycidyl *** of RDX or HMX,respectively,into the BCHX PBXs gives ternary PBXs whose thermal stability,in the sense of applied VST,is higher comparing to the original binary explosives.

关键词： Enthalpy Explosive strength Combustion Nitramines PBX Thermal stability

Solitary kinetic Alfven waves in dense plasmas with relativistic degenerate electrons and positrons

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2019年第4期21卷 85-93页

作者： Monzurul k ahmed Om P SAH Department of Physics Biijhora MahavidyalayaBongaigaon-783380AssamIndia

Propagation of solitary kinetic Alfven waves(kAWs)is investigated in small but finite/3(particle-to-magnetic pressure ratio)collisionless dense plasma whose constituents are non degenerate wann ions,and relativistic degenerate electrons and *** the use of reductive perturbation technique,kortweg-de Vries equation is derived to obtain small amplitude localized wave solution of *** effects of plasma 0,positron concentration,electron relativistic degeneracy parameter,ion thermal temperature and obliqueness parameter on solitary kAWs are *** results of this theoretical investigation are aimed at elucidating characteristics of kinetic Alfven solitary waves in relativistic degenerate e-p-i plasmas found in dense astrophysical objects specifically neutron stars and white dwarfs.

关键词： solitary kinetic Alfven waves dense plasmas electron-positron-ion plasma,relativistic degenerate plasma reductive perturbation technique

Solitary kinetic Alfvén waves in a dense electron–positron–ion plasma with degenerate electrons and positrons

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2017年第12期19卷 42-49页

作者： Monzurul k ahmed Om P SAH Depatment of Physics Birjhora MahavidyalayaBongaigaon-783380AssamIndia

Through the use of a reductive perturbation technique, solitary kinetic Alfvén waves（kAWs） are investigated in a low but finite b（particle-to-magnetic pressure ratio） dense electron–positron–ion plasma where electrons and positrons are degenerate. The degenerate plasma model considered here permits the existence of sub-Alfvénic compressive solitary kAWs. The influence of r（equilibrium positron-to-ion density ratio）, sF（electron-to-positron Fermi temperature ratio）, b and obliqueness parameter lzon various characteristics of solitary kAWs are examined through numerical plots. We have shown that there exists a critical value of lzat which a soliton width attains its maximum value which decreases with an increase in r and *** is also found that solitons with a higher energy propagate more obliquely in the direction of an ambient magnetic field. The results of the present investigation may be useful for understanding low frequency nonlinear electromagnetic wave propagation in magnetized electron–positron–ion plasmas in dense stars. Specifically, the relevance of our investigation to a pulsar magnetosphere is emphasized.

关键词： kinetic Alfvén waves solitons electron–positron–ion plasma degenerate plasma Thomas–Fermi approximation

Connected Components-based Colour Image Representations of Vibrations for a Two-stage Fault Diagnosis of Roller Bearings Using Convolutional Neural Networks

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2021年第3期34卷 73-93页

作者： Hosameldin O.A.ahmed Asoke k Nandi Department of Electronic and Electrical Engineering Brunel University LondonUxbridge UB83PHUK School of Mechanical Engineering Xi’an Jiaotong UniversityXi’anChina

Roller bearing failure is one of the most common faults in rotating *** techniques for bearing fault diagnosis based on faults feature extraction have been *** feature extraction from fault signals requires expert prior information and human ***,deep learning algorithms have been applied extensively in the condition monitoring of rotating machines to learn features automatically from the input *** its robust performance in image recognition,the convolutional neural network(CNN)architecture has been widely used to learn automatically discriminative features from vibration images and classify health *** paper proposes and evaluates a two-stage method RGBVI-CNN for roller bearings fault *** first stage in the proposed method is to generate the RGB vibration images(RGBVIs)from the input vibration *** begin this process,first,the 1-D vibration signals were converted to 2-D grayscale vibration *** the conversion was completed,the regions of interest(ROI)were found in the converted 2-D grayscale vibration ***,to produce vibration images with more discriminative characteristics,an algorithm was applied to the 2-D grayscale vibration images to produce connected components-based RGB vibration images(RGBVIs)with sets of colours and texture *** the second stage,with these RGBVIs a CNN-based architecture was employed to learn automatically features from the RGBVIs and to classify bearing health *** cases of fault classification of rolling element bearings are used to validate the proposed *** results of this investigation demonstrate that RGBVI-CNN can generate advantageous health condition features from bearing vibration signals and classify the health conditions under different working loads with high ***,several classification models trained using RGBVI-CNN offered high performance in the testing results of the overall classification accura

关键词： Bearing fault diagnosis Image representation of vibrations Deep learning Convolutional neural networks

Finite element modeling assumptions impact on seismic response demands of MRF-buildings

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2018年第4期17卷 821-834页

作者： Shehata E Abdel Raheem ahmed k Abdel Zaher ahmed MA Taha Civil Engineering Department Engineering College Taibah University Civil Engineering Department Faculty of Engineering Assiut University

Recent seismic events have raised concerns over the safety and vulnerability of reinforced concrete moment resisting frame ＂RC-MRF＂ buildings. The seismic response of such buildings is greatly dependent on the computational tools used and the inherent assumptions in the modelling process. Thus, it is essential to investigate the sensitivity of the response demands to the corresponding modelling assumption. Many parameters and assumptions are justified to generate effective structural finite element（FE） models of buildings to simulate lateral behaviour and evaluate seismic design demands. As such, the present study focuses on the development of reliable FE models with various levels of refinement. The effects of the FE modelling assumptions on the seismic response demands on the design of buildings are investigated. the predictive ability of a FE model is tied to the accuracy of numerical analysis; a numerical analysis is performed for a series of symmetric buildings in active seismic zones. The results of the seismic response demands are presented in a comparative format to confirm drift and strength limits requirements. A proposed model is formulated based on a simplified modeling approach, where the most refined model is used to calibrate the simplified model.

关键词： RC-MRF buildings design codes provisions seismic design finite element modeling modeling assumptions response demands

An energetic nano-fiber composite based on polystyrene and 1,3,5-trinitro-1,3,5-triazinane fabricated via electrospinning technique

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2023年第9期27卷 1-8页

作者： Mahmoud Abdelhafiz ahmed k.Hussein Waleed F.khalil ahmed Elbeih Military TechnicalCollege(MTC) KobryElkobbahCairoEgypt Safety FuelCycleDepartment NRSRCEgyptianAtomicEnergyAuthority(EAEA)CairoEgypt

Electrospinning is a simple technique used to fabricate polymeric nano-fibrous *** nano-fibers have found a wide range of valuable applications in the biomedical ***,it has not been utilized with solid high explosives ***,the electrospinning technique has been used to fabricate polystyrene(PS)/1,3,5-trinitro-1,3,5-triazinane(RDX)composite *** governed electrospinning parameters,voltage,distance from the collector,flow rate,mandrel rotating speed,time,and solution concentration,that greatly affect the morphology of the obtained nanofibers were *** fabricated PS/RDX nano-fibers were characterized using scanning electron microscopy(SEM),X-ray diffractometer(XRD),and Fourier Transform Infrared(FTIR)*** impact and friction sensitivities of PS/RDX were also *** thermal behavior of the prepared composite and the pure materials were studied by the thermal gravimetric analysis technique(TGA).SEM results proved the fabrication of PS/RDX fibers in the nano-size via *** spectroscopy confirmed the existence of the characteristic functional groups of both PS and RDX in the composite *** sharp peaks showed the conversion of amorphous PS into crystalline shape via electrospinning and also confirmed the formation of PS/RDX *** PS fibers absorbed the heat and increased the onset decomposition of the pure RDX from 181.5 to 200.7℃in the case of PS/RDX ***,PS/RDX nano-fibers showed the relatively low impact and friction sensitivities of 100 J and 360 N *** results could introduce PS/RDX nanofibrous composite in the field of explosives detection with high levels of safety.

关键词： Electrospinning Nano-fibers 1,3,5-Trinitro-1,3,5-triazinane(RDX) Polystyrene(PS) Sensitivity