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Development of niobium-promoted cobalt catalysts on carbon nanotubes for Fischer-Tropsch synthesis

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Journal of Natural Gas Chemistry 2011年第6期20卷 659-663页

作者： sardar ali Noor Asmawati Mohd Zabidi Duvvuri Subbarao Department of Chemical Engineering Universiti Teknologi PETRONASBandar Seri Iskandar31750 TronohPerakMalaysia Department of Fundamental and Applied Sciences Universiti Teknologi PETRONASBandar Seri Iskandar31750 TronohPerakMalaysia

Cobalt-based catalysts were prepared by a wet impregnation method on carbon nanotubes （CNTs） support and promoted with *** were characterized by nitrogen adsorption,TEM,XRD,TPR,TPO and *** of niobium increased the dispersion of cobalt but decreased the catalysts ***-Tropsch synthesis （FTS） was carried out in a fixed-bed microreactor at 543 K,1 atm and H2/CO=2 for 5 *** of niobium enhanced the C5＋ hydrocarbons selectivity by 39% and reduced methane selectivity by 59%.These effects were more pronounced for 0.04%Nb/Co/CNTs catalyst,compared with those observed for other niobium compositions.

关键词： CNTs cobalt niobium Fischer-Tropsch synthesis

KurdSet: A Kurdish Handwritten Characters Recognition Dataset Using Convolutional Neural Network

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Computers, Materials & Continua 2024年第4期79卷 429-448页

作者： sardar Hasen ali Maiwan Bahjat Abdulrazzaq Computer Science Department University of ZakhoDuhokIraq

Handwritten character recognition(HCR)involves identifying characters in images,documents,and various sources such as forms surveys,questionnaires,and signatures,and transforming them into a machine-readable format for subsequent *** recognizing complex and intricately shaped handwritten characters remains a significant *** use of convolutional neural network(CNN)in recent developments has notably advanced HCR,leveraging the ability to extract discriminative features from extensive sets of raw *** of the absence of pre-existing datasets in the Kurdish language,we created a Kurdish handwritten dataset called(KurdSet).The dataset consists of Kurdish characters,digits,texts,and *** dataset consists of 1560 participants and contains 45,240 *** this study,we chose characters only from our *** utilized a Kurdish dataset for handwritten character *** study also utilizes various models,including InceptionV3,Xception,DenseNet121,and a *** show the performance of the KurdSet dataset,we compared it to Arabic handwritten character recognition dataset(AHCD).We applied the models to both datasets to show the performance of our ***,the performance of the models is evaluated using test accuracy,which measures the percentage of correctly classified characters in the evaluation *** models performed well in the training phase,DenseNet121 exhibited the highest accuracy among the models,achieving a high accuracy of 99.80%on the Kurdish *** Xception model achieved 98.66%using the Arabic dataset.

关键词： CNN models Kurdish handwritten recognition KurdSet dataset Arabic handwritten recognition DenseNet121 model InceptionV3 model Xception model

Tsunami hazard in the shorelines of Khark island (Persian Gulf),Iran

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Earthquake Science 2012年第4期25卷 299-305页

作者： Mehdi Zaré Seyed-Ahmad Hashemi Roya Ebadi Sahar Amirnejad-Mojdehi Roya Rahmani ali sardar International Institute of Earthquake Engineering and Seismology Iranian Oil Terminals Comyany

Iran is located in one of the seismically active regions of the world. Due to the high probability of earthquakes throughout the country and the potential for tsunami inundation along the coasts and offshore, comprehensive studies on theinteraction of these natural phenomena arc necessary, hi this study, the most conservative scenarios are determined for possible earthquakes within the Khark zone （Persian Gulf） *** on experimental relations between tile fault length, magnitude and displacement, which are paralneters for deter- mining tsunamigenic sources. Subsequently, the maximum height of tstmami waves are calculated based on the specitieations of the seismic source and its distance from the shore as well as the coastal slope. A zoning map of tsunami hazard is finally presented.

关键词： tsunami Khark island seismotectonic seismic source

Synthesis and Characterization of Co/Mo Bimetallic Nanocatalysts

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材料科学与工程（中英文A版） 2011年第3X期1卷 390-397页

作者： sardar ali Noor Asmawati Mohd Zabidi Duvvuri Subbarao Department of Chemical Engineering Universiti Teknologi PETRONAS Bandar Seri lskandar Tronoh 31750 Perak Malaysia Department of Fundamental and Applied Sciences Universiti Teknologi PETRONAS Bandar Seri lskandar Tronoh 31750 Perak Malaysia

Cobalt/Molybdenum bimetallic nanocatalysts were prepared by wet impregnation method on alumina support. Samples 22 adsorption-desorption analyses. Fischer-Tropsch synthesis (FTS) was carried out in a fixed-bed microreactor at 543 K and 1 atm, with H2/CO = 2 v/v and space velocity, SV = 12 L/g·h. The physicochemical properties and the FTS performance of the bimetallic nanocatalysts were analyzed and compared with the monometallic cobalt and molybdenum nanocatalysts. H2-TPR analysis of cobalt nanocatalyst indicated three temperature regions at 490 οC (low temperature), 710 οC (medium temperature) and 820 οC (high temperature). The incorporation of molybdenum into cobalt nanocatalysts increased the percentage of species reduced at low temperature. It also increased the average size of metal nanoparticles and enhanced hydrogen chemisorptions but decreased the degree of reduction of bimetallic nanocatalysts compared to those of the monometallic nanocatalysts. Bimetallic nanocatalysts enhanced the %CO conversion in the FTS. Among the nanocatalysts studied, bimetallic nanocatalyst with the composition of 50Co:50Mo resulted in the highest %CO conversion (42.6%), while the %CO conversion was 28.3% and 24%, respectively for the monometallic cobalt and molybdenum nanocatalysts.

关键词：纳米催化剂双金属金属钴表征合成 H2/CO CO转化率透射电子显微镜

Modelling of debris-flow susceptibility and propagation: a case study from Northwest Himalaya

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Journal of Mountain Science 2024年第1期21卷 200-217页

作者： Hamza DAUD Javed Iqbal TANOLI sardar Muhammad ASIF Muhammad QASIM Muhammad ali Junaid KHAN Zahid Imran BHATTI Ishtiaq Ahmad Khan JADOON Badong National Observation and Research Station of Geohazards China University of GeosciencesWuhan 430074China Department of Earth Sciences COMSATS University IslamabadAbbottabad Campus 22010Pakistan Department of Earth Sciences Sultan Qaboos UniversityAl-KhoudMascat 123Oman Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China Department of Earth Sciences Abbottabad University of Science and TechnologyHavelian 22500Pakistan

The geological and geographical position of the Northwest Himalayas makes it a vulnerable area for mass movements particularly landslides and debris flows. Mass movements have had a substantial impact on the study area which is extending along Karakorum Highway(KKH) from Besham to Chilas. Intense seismicity, deep gorges, steep terrain and extreme climatic events trigger multiple mountain hazards along the KKH, among which debris flow is recognized as the most destructive geohazard. This study aims to prepare a field-based debris flow inventory map at a regional scale along a 200 km stretch from Besham to Chilas. A total of 117 debris flows were identified in the field, and subsequently, a point-based debris-flow inventory and catchment delineation were performed through Arc GIS analysis. Regional scale debris flow susceptibility and propagation maps were prepared using Weighted Overlay Method(WOM) and Flow-R technique sequentially. Predisposing factors include slope, slope aspect, elevation, Topographic Roughness Index(TRI), Topographic Wetness Index(TWI), stream buffer, distance to faults, lithology rainfall, curvature, and collapsed material layer. The dataset was randomly divided into training data(75%) and validation data(25%). Results were validated through the Receiver Operator Characteristics(ROC) curve. Results show that Area Under the Curve(AUC) using WOM model is 79.2%. Flow-R propagation of debris flow shows that the 13.15%, 22.94%, and 63.91% areas are very high, high, and low susceptible to debris flow respectively. The propagation predicated by Flow-R validates the naturally occurring debris flow propagation as observed in the field surveys. The output of this research will provide valuable input to the decision makers for the site selection, designing of the prevention system, and for the protection of current infrastructure.

关键词： North Pakistan Debris flow Flow-R Propagation Susceptibility mapping Debris-flow inventory Weighted Overlay Method

A Game-Theoretic Approach to Safe Crowd Evacuation in Emergencies

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Computers, Materials & Continua 2024年第4期79卷 1631-1657页

作者： Maria Gul Imran ali Khan Gohar Zaman Atta Rahman Jamaluddin Mir sardar Asad ali Biabani May IssaAldossary Mustafa Youldash Ashraf Saadeldeen Maqsood Mahmud Asiya Abdus Salam Dania Alkhulaifi Abdullah AlTurkey31Department of Computer Science COMSATS University IslamabadAbbottabad CampusAbbottabad22010Pakistan Department of Computer Science Abbottabad University of Science and TechnologyAbbottabad22010Pakistan Department of Computer Science College of Computer Science and Information TechnologyImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Science and Technology Unit Umm Al-Qura UniversityMakkah21955Saudi Arabia Deanship of Scientific Research Umm Al-Qura UniversityMakkah21955Saudi Arabia Department of Computer Information Systems College of Computer Science and Information TechnologyImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Department of Computer Engineering College of Computer Science and Information TechnologyImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Department of Computer Science Faculty of Computer Science and Information TechnologyOmdurman Islamic UniversityOmdurman14415Sudan Business Analytic Program Department of Management and MarketingCollege of Business AdministrationUniversity of BahrainSakhir32038Bahrain

Obstacle removal in crowd evacuation is critical to safety and the evacuation system efficiency. Recently, manyresearchers proposed game theoreticmodels to avoid and remove obstacles for crowd evacuation. Game theoreticalmodels aim to study and analyze the strategic behaviors of individuals within a crowd and their interactionsduring the evacuation. Game theoretical models have some limitations in the context of crowd evacuation. Thesemodels consider a group of individuals as homogeneous objects with the same goals, involve complex mathematicalformulation, and cannot model real-world scenarios such as panic, environmental information, crowds that movedynamically, etc. The proposed work presents a game theoretic model integrating an agent-based model to removethe obstacles from exits. The proposed model considered the parameters named: (1) obstacle size, length, andwidth, (2) removal time, (3) evacuation time, (4) crowd density, (5) obstacle identification, and (6) route *** proposed work conducts various experiments considering different conditions, such as obstacle types, obstacleremoval, and several obstacles. Evaluation results show the proposed model’s effectiveness compared with existingliterature in reducing the overall evacuation time, cell selection, and obstacle removal. The study is potentially usefulfor public safety situations such as emergency evacuations during disasters and calamities.

关键词： Safe crowd evacuation public safety emergency transition probability cooperation

Adsorption of CO<sub>2</sub>on Polyethyleneimine 10k—<i>Mesoporous silica</i>Sorbent: XPS and TGA Studies

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American Journal of Analytical Chemistry 2015年第4期6卷 274-284页

作者： M. M. Khader M. J. Al-Marri sardar ali G. Qi E. P. Giannelis Gas Processing Center College of Engineering Qatar University Doha Qatar Department of Materials Science and Engineering Cornell University Ithaca NY USA

A CO2 solid sorbent based on polyethyleneimine 10k (PEI-10k) impregnated into mesoporous silica (MPS) foam was synthesized and utilized to capture CO2 at temperatures ranged from 65°C to 95°C. The calculated nitrogen and carbon contents in the bulk of the PEI-10k/MPS sorbent were similar to the XPS results measured on the surface of the foam, suggesting that the PEI was homo-geneously distributed throughout the MPS support. After CO2 adsorptionthe N 1s peak was broadened and could be resolved into two components: a high binding energy component (~401 eV) and a lower binding energy one (396 eV), respectively. The former nitrogen states are consistent with a protonated amine, presumably, due to carbamate formation. The lower binding energy component (~396 eV) could possibly be due to strongly chemisorbed CO2. The maximum sorption capacity was about 4 mmole CO2/g sorbent at 85°C and 1 bar. This capacity was doubled by raising the CO2 pressure to 24.95 bars. The adsorption results can be described by a Langmuir adsorption isotherm.

关键词： XPS Adsorption Isotherm of CO2 Polyethyleneimine 10k Mesoporous silica

Effects of Pressure on the Performance of CNTs-Supported Catalyst in a Fischer-Tropsch Reaction

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材料科学与工程（中英文B版） 2014年第2期4卷 28-33页

作者： Noor Asmawati Mohd Zabidi sardar ali Duvvuri Subbarao Department of Fundamental and Applied Sciences Universiti Teknologi PETRONAS Bandar Seri Iskandar Tronoh 31750 PerakMalaysia Department of Chemical Engineering Universiti Teknologi PETRONAS Bandar Seri Iskandar Tronoh 31750 Perak Malaysia

Fischer-Tropsch (FT) reaction involves conversion of syngas (a mixture of carbon monoxide and hydrogen) into higher hydrocarbons in the presence of an active catalyst. The syngas can be derived from non-petroleum feedstocks such as coal, biomass and natural gas, thus the FT reaction provides an alternative route for production of clean fuels. The FT process has received growing interest in recent years due to uncertainty in the Middle East, fast depletion of fossil fuel and environmental concern. This paper reports the synthesis, physicochemical properties and catalytic performance of cobalt-based catalyst in the FT reaction. The catalysts comprised metal nanoparticles supported on carbon nanotubes (CNTs) which were synthesized via a wet impregnation method. The catalysts were characterized using transmission electron microscopy (TEM), temperature-programmed reduction/desorption (TPR/TPD) and X-ray photoelectron spectroscopy (XPS). The performance of the cobalt-based catalyts in a FT reaction was evaluated in a fixed bed microreactor equipped with an on-line gas chromatograph for analyses of hydrocarbon products. The catalysts investigated in this work were Co/CNTs, 70Co30Mn/CNTs, 0.06%K/70Co30Fe/CNTs and 0.04%Nb/70Co30Fe/CNTs. TEM analyses revealed that the average sizes of the metal nanoparticles were 4-5 nm. Based on TPD analyses, the dispersion of these nanoparticles on CNTs were greater than 90%. The presence of both Co2+ and Co3+ ions were confirmed by XPS analysis. The 0.04%Nb/70Co30Fe/CNTs catalyst performed better than other catalysts in the FT reaction where it resulted in CO conversion of 35% and 16% C5+ selectivity at pressure of 1 bar, 220 °C and H2: CO of 2:1. Using the same catalyst, the CO conversion and C5+ selectivity increased to 60% and 57%, respectively when the pressure was increased to 20 bar.

关键词：负载型催化剂反应性能碳纳米管压力升高合成气金属纳米颗粒 X射线光电子能谱钴基催化剂

Syntheses,Spectral Studies and Bioanalyses of Some Triorganotin(IV) Complexes of Cephlaxine

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Chinese Journal of Structural Chemistry 2008年第7期27卷 846-852页

作者： Wajid Rehman Bakhtiar Muhammad Farman ali sardar Atif Department of Chemistry Hazara University MansehraPakistan

Five novel triorganotin（IV） complexes have been synthesized by refluxing trimethyl, triethyl, tributyl, triphenyl and tribenzyltin chloride with Cephlaxine. These compounds were characterized by spectroscopic （IR, IH, 13C, 119Sn NMR） techniques and elemental analysis. The results obtained through these techniques are in full agreement with the proposed 1：1 stoichiometry. The synthesized compounds were than tested against various microorganisms and fungi. The results of new products obtained showed that the triphenyltin（IV） complex displayed promising activity against all types of bacteria and fungi used while all other compounds showed significant antibacterial and antifungal activity.

关键词： cephlaxine spectra triorganotin activity bacteria