检索结果-南通市图书馆

Understanding the catalytic performance and deactivation behaviour of second-promoter doped Pt/WO_(χ)/γ-Al_(2)O_(3) catalysts in the glycerol hydrogenolysis for selective and cleaner production of 1,3-propanediol

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第7期94卷 486-507页

作者： Rafik Rajjak shaikh Sittichai Damruang Rais ahmad Khan Supareak Praserthdam Piyasan Praserthdam Center of Excellence on Catalysis and Catalytic Reaction Engineering(CECC) Department of Chemical EngineeringFaculty of EngineeringChulalongkorn UniversityBangkok 10330Thailand Department of Chemistry College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia High-Performance Computing Unit(CECC-HCU) Centre of Excellence on Catalysis and Catalytic Reaction Engineering(CECC)Department of Chemical EngineeringFaculty of EngineeringChulalongkorn UniversityBangkok 10330Thailand

The selective aqueous-phase glycerol hydrogenolysis is a promising reaction to produce commercially useful 1,3-propanediol(1,3-PDO).The Pt-WOx bifunctional catalyst can catalyse the glycerol hydrogenol-ysis but the catalyst deactivation via sintering,metal leaching,and coking can predominantly occur in the aqueous phase *** this work,the effect of reaction temperature,pressure and second promoter(Cu,Fe,Rh,Mn,Re,Ru,Ir,Sn,B,and P)on catalytic performance and deactivation behaviour of Pt/WOx/-Al2O3 was *** doped with Rh,Mn,Re,Ru,Ir,B,and P,the second promoter boosts catalytic activity by promoting great dispersion of Pt on support and increasing Pt surface *** increased Bronsted acid sites lead to selective synthesis of 1,3-PDO than 1,2-propanediol(1,2-PDO).The characterization studies of fresh and spent catalysts reveal that the main cause of catalyst deactivation is the Pt sintering,as interpreted based on XRD,CO chemisorption,and TEM *** Pt sintering is affected depending on the second promoter that can either or reduce the interaction between Pt,WO_(χ)/γ and Al_(2)O_(3).As an electron acceptor of Pt in Pt/WO_(χ)/γ-Al_(2)O_(3),Re and Mn as second promoters resulted in increased Pt^(2+) on the catalytic surface,which strengthens the contact between Pt andγ-Al_(2)O_(3) and WO_(χ),resulting in a decrease in Pt *** metal leaching and coking are not affected by the presence of second *** catalyst modified with a second promoter possesses improved catalytic activity and 1,3-PDO production,however the stability continues to remain a *** present work unrav-elled the determining parameters of catalytic activity and deactivation,thus providing a promising pro-tocol toward effective catalysts for glycerol hydrogenolysis.

关键词： Glycerol hydrogenolysis 1,3-propanediol Metal-support interaction Second promoter Liquid phase Catalyst deactivation

Robust design of sliding mode control for airship trajectory tracking with uncertainty and disturbance estimation

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第1期35卷 242-258页

作者： WASIM Muhammad ALI Ahsan CHOUDHRY Mohammad ahmad shaikh Inam Ul Hasan SALEEM Faisal Department of Aeronautics and Astronautics Engineering Institute of Space TechnologyIslamabad 44000Pakistan Department of Electrical Engineering University of Engineering and TechnologyTaxila 47080Pakistan Department of Measurements and Control Systems Silesian University of TechnologyGliwice 44-101Poland The Joint Doctoral School Silesian University of TechnologyGliwice 44-100Poland

The robotic airship can provide a promising aerostatic platform for many potential *** applications require a precise autonomous trajectory tracking control for *** has a nonlinear and uncertain *** is prone to wind disturbances that offer a challenge for a trajectory tracking control *** paper addresses the airship trajectory tracking problem having time varying reference path.A lumped parameter estimation approach under model uncertainties and wind disturbances is opted against distributed *** uses extended Kalman filter(EKF)for uncertainty and disturbance *** estimated parameters are used by sliding mode controller(SMC)for ultimate control of airship trajectory *** comprehensive algorithm,EKF based SMC(ESMC),is used as a robust solution to track airship *** proposed estimator provides the estimates of wind disturbances as well as model uncertainty due to the mass matrix variations and aerodynamic model *** stability and convergence of the proposed method are investigated using the Lyapunov stability *** simulation results show that the proposed method efficiently tracks the desired *** method solves the stability,convergence,and chattering problem of SMC under model uncertainties and wind disturbances.

关键词： airship chattering extended Kalman filter(EKF) model uncertainties estimation sliding mode controller(SMC)

Triad-displaced ULAs configuration for non-circular sources with larger continuous virtual aperture and enhanced degrees of freedom

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第1期35卷 81-93页

作者： shaikh Abdul Hayee DANG Xiaoyu HUANG Daqing College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteristics play a significant role in improving the direction-of-arrival(DOA)estimation ***,most of the existing NULA geometries are primarily applicable to circular sources(CSs),while they limitedly improve the DOF and continuous virtual aperture for noncircular sources(NCSs).Toward this purpose,we present a triaddisplaced ULAs(Tdis-ULAs)configuration for *** TdisULAs structure generally consists of three ULAs,which are appropriately *** proposed antenna array approach fully exploits the non-circular characteristics of the *** the same number of elements,the Tdis-ULAs design achieves more DOF and larger hole-free co-array aperture than its sparse array ***,the number of uniform DOF,optimal distribution of elements among the ULAs,and precise element positions are uniquely determined by the closed-form ***,the proposed array also produces a filled resulting *** simulations are conducted to show the performance advantages of the proposed Tdis-ULAs configuration over its counterpart designs.

关键词： direction-of-arrival(DOA)estimation sparse array non-circular source(NCS) sum co-array difference co-array degrees of freedom(DOF)

Fine Sand and Clay Sediment Acoustic Properties of the Novel Sediment Sample from the Arabian Sea:Experimental Investigations and Biot−Stoll Model Validation

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第1期38卷 169-180页

作者： Shahabuddin shaikh HUANG Yi-wang ZHANG Ze-chuan Habib Hussain ZUBERI National Key Laboratory of Underwater Acoustic Technology and College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China

The present study explores the physical and acoustic characteristics of fine sand and clay in novel seabed marine sediments from of Pakistan coastline of the Arabian *** measured physical parameters included mean grain size,mass density,bulk density,salinity,porosity,permeability,pore size and mineralogical *** properties,including sound speed and attenuation,in the high frequency range of 90-170 kHz were analyzed.A controlled laboratory setup with the acoustic transmission method and Fourier transform techniques was utilized to examine the sound propagation and absorption of novel seabed *** standard deviation of mean sound speed in fresh water was 0.75 m/s,and attenuation was observed in the range of 0.43 to 0.61 dB/*** mean sound velocity in sand and clay varied from 1706 to 1709 m/s and 1602 to 1608 m/s,*** average attenuation was observed at 80 to 93 dB/m in sandy sediments and from 31.8 to 38.6 dB/m in clayey *** velocity variation within sandy sediment is low,consistent with expected results,and smaller than the predicted ***,clay sediment exhibited a positive linear correlation and low sound speed *** increased linearly with frequency for both ***,the laboratory results were validated by using the Biot−Stoll *** dispersion of sound speed in sandy and clayey sediments was consistent with the predictions of the Biot−Stoll *** attenuation aligned more with Biot−Stoll model predictions due to improved permeability,tortuosity and pore size parameter fitting.

关键词： physical and acoustic characteristics marine sediments sound speed attenuation Biot−Stoll model

Geomorphic signatures and active tectonics in western Saurashtra,Gujarat,India

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2024年第1期15卷 82-99页

作者： Bikramaditya Mondal Mery Biswas Soumyajit Mukherjee Mohamedharoon A.shaikh Department of Earth Sciences Indian Institute of Technology BombayMumbai 400076MaharashtraIndia Department of Geography Presidency UniversityKolkata 700073West BengalIndia

Active tectonics in an area includes ongoing or recent geologic *** paper investigates the tectonic influence on the subsidence,uplift and tilt of western Saurashtra through morphotectonic analysis of ten watersheds along with characteristics of relief and drainage *** 7-9 to the north(N)are tectonically active,which can be linked with the North Kathiawar Fault System(NKFS)and followed by watersheds 6,10,1,4 and ***-length gradient index and sinuosity index indicate the effect of tectonic events along the master streams in watersheds *** R^(2)values of the linear curve fit for watershed 7 indicate its master stream is much more tectonically active than the *** R^(2)curve fitting model and earthquake magnitude/depth analysis confirm the region to be *** reactivation of the NKFS most likely led to the vertical movement of western Saurashtra.

关键词： Active tectonics Geomorphology Western Saurashtra Archeology North kathiawar fault system

Sustainable bio-energy generation via the conversion of spent wash using dual chamber microbial fuel cell

在线全文

学校读者我要写书评

暂无评论

Waste Disposal and Sustainable Energy 2024年第2期6卷 219-231页

作者： Abdul Sattar Jatoi Jawad Ahmed Afaque Ahmed Bhutto Muhammad Shuaib shaikh Department of Chemical Engineering Dawood University of Engineering and Technology KarachiSindhPakistan Changzhou DUBO Polymer Co. Ltd.Changzhou 213002China Department of Basic Science and Related Studies The University of LarkanoSindhPakistan Department of Chemical Engineering Mehran University of Engineering and Technology JamshoroSindhPakistan

Microbial fuel cells(MFCs)are innovative devices that combine microbial processes with electrochemical reactions to convert organic matter in wastewater into electricity while simultaneously treating the *** such application is the treatment of spent wash,a highly polluting effluent generated from the distillery industry after crude mesh is separated into ethanol and spent *** wash,also known as distillery effluent or stillage,is a highly challenging wastewater treatment method due to its high chemical oxygen demand(COD),biological oxygen demand(BOD),and total dissolved solids(TDS).These characteristics make it a complex and polluting industrial effluent that requires specialized treatment processes to reduce its environmental impact ***,MFCs have shown promise in treating spent wash,as they can utilize the organic matter in wastewater as a fuel source for microbial growth as well as for electricity *** the treatment of spent wash,Saccharomyces cerevisiae *** used as a biocatalyst along with 340 mol/L potassium ferricyanide in the cathode chamber and 170 mol/L methylene blue in the anode as a *** tests were conducted by balancing a one-liter volume for power production from spent wash in MFC with the optimal conditions of 10%agarose,pH 8.5,300 mL/min of aeration in the cathode chamber,and 40%(in weight)substrate *** an ideal concentration,the maximum current and power density are roughly 53.41 mA/m^(2)and 72.22 mW/m^(2),*** each litre of processed spent wash,a maximum voltage of 850 mV(4.5 mA)was ***,91%of COD and BOD were removed from the effluent *** findings show that MFCs are capable of producing electricity and efficiently removing COD from wasted wash at the same time.

关键词： Microbial fuel cell Chemical oxygen demand Biological oxygen demand-Current density Power density Spent wash

Metabolic puzzle: Exploring liver fibrosis differences in Asian metabolic-associated fatty liver disease subtypes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Hepatology 2024年第1期16卷 54-64页

作者： Sabhita Shabir shaikh Fakhar Ali Qazi-Arisar Saba Nafay Sidra Zaheer Hafeezullah shaikh Zahid Azam National Institute of Liver and GI Diseases Dow University of Health SciencesSindhKarachi 75330Pakistan School of Public Health Dow University of Health SciencesSindhKarachi 75330Pakistan

BACKGROUND Metabolic-associated fatty liver disease(MAFLD)is a liver condition marked by excessive fat buildup in the absence of heavy alcohol *** is primarily linked with metabolic issues like insulin resistance,obesity,and abnormal lipid levels,and is often observed with other conditions such as type 2 diabetes and cardiovascular ***,whether the subtypes of MAFLD based on the metabolic disorder differentially impact liver fibrosis is not well explicated,especially in the Asian *** To compare the severity of liver fibrosis among different MAFLD *** A total of 322 adult patients of either gender with fatty liver on ultrasound were enrolled between January to December *** was defined as per the Asian Pacific Association for the Study of the Liver ***-4 index(Fib-4)and nonalcoholic fatty liver disease fibrosis score(NFS)were employed to evaluate liver *** The mean age was 44.84±11 ***-two percent of the patients were *** hundred and seventy-three patients were classified as having MAFLD,of which 110(40.3%)carried a single,129(47.3%)had two,and 34(12.5%)had all three metabolic *** cumulative number of metabolic conditions was related to elevated body mass index,triglyceride(TG)levels,and glycated hemoglobin,lower high-density lipoprotein(HDL)levels,higher liver inflammation(by aspartate aminotransferase andγ-glutamyl transferase),and higher likelihood of fibrosis(by NFS and Fib-4 scores)(P<0.05 for all).The proportion of advanced fibrosis also increased with an increase in the number of metabolic conditions(4.1%,25.5%,35.6%,and 44.1%by NFS and 6.1%,10.9%,17%,and 26.5%by Fib-4 for no MAFLD and MAFLD with 1,2,and 3 conditions,respectively).Among MAFLD patients,those with diabetes alone were the eldest and had the highest mean value of NFS score and Fib-4 score(P<0.05),while MAFLD patients diagnosed with lean metabolic dysfunction exhibited the highest levels of TG and a

关键词： Metabolic syndrome Diabetes Fatty liver disease Dyslipidemia Obesity

Social Media-Based Surveillance Systems for Health Informatics Using Machine and Deep Learning Techniques:A Comprehensive Review and Open Challenges

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第5期139卷 1167-1202页

作者： Samina Amin Muhammad Ali Zeb Hani Alshahrani Mohammed Hamdi Mohammad Alsulami Asadullah shaikh Institute of Computing Kohat University of Science and TechnologyKohat26000Pakistan Department of Computer Science College of Computer Science and Information SystemsNajran UniversityNajran61441Saudi Arabia Department of Information System College of Computer Science and Information SystemsNajran UniversityNajran61441Saudi Arabia

Social media(SM)based surveillance systems,combined with machine learning(ML)and deep learning(DL)techniques,have shown potential for early detection of epidemic *** review discusses the current state of SM-based surveillance methods for early epidemic outbreaks and the role of ML and DL in enhancing their ***,every year,a large amount of data related to epidemic outbreaks,particularly Twitter data is generated by *** paper outlines the theme of SM analysis for tracking health-related issues and detecting epidemic outbreaks in SM,along with the ML and DL techniques that have been configured for the detection of epidemic *** has emerged as a promising ML technique that adaptsmultiple layers of representations or features of the data and yields state-of-the-art extrapolation *** recent years,along with the success of ML and DL in many other application domains,both ML and DL are also popularly used in SM *** paper aims to provide an overview of epidemic outbreaks in SM and then outlines a comprehensive analysis of ML and DL approaches and their existing applications in SM ***,this review serves the purpose of offering suggestions,ideas,and proposals,along with highlighting the ongoing challenges in the field of early outbreak detection that still need to be addressed.

关键词： Social media epidemic machine learning deep learning health informatics pandemic

Low-complexity signal detection for massive MIMO systems via trace iterative method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第3期35卷 549-557页

作者： IMRAN A.Khoso ZHANG Xiaofei ABDUL Hayee shaikh IHSAN A.Khoso ZAHEER Ahmed Dayo College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China School of Electrical Engineering Korea UniversitySeoul 02841Korea School of Mathematics South China University of TechnologyGuangzhou 510641China Department of Computer Science Huanggang Normal UniversityHuanggang 438000China

Linear minimum mean square error(MMSE)detection has been shown to achieve near-optimal performance for massive multiple-input multiple-output(MIMO)systems but inevitably involves complicated matrix inversion,which entails high *** avoid the exact matrix inversion,a considerable number of implicit and explicit approximate matrix inversion based detection methods is *** combining the advantages of both the explicit and the implicit matrix inversion,this paper introduces a new low-complexity signal detection ***,the relationship between implicit and explicit techniques is ***,an enhanced Newton iteration method is introduced to realize an approximate MMSE detection for massive MIMO uplink *** proposed improved Newton iteration significantly reduces the complexity of conventional Newton ***,its complexity is still high for higher ***,it is applied only for first two *** subsequent iterations,we propose a novel trace iterative method(TIM)based low-complexity algorithm,which has significantly lower complexity than higher Newton *** guarantees of the proposed detector are also *** simulations verify that the proposed detector exhibits significant performance enhancement over recently reported iterative detectors and achieves close-to-MMSE performance while retaining the low-complexity advantage for systems with hundreds of antennas.

关键词： signal detection low-complexity linear minimum mean square error(MMSE) massive multiple-input multiple-output(MIMO) trace iterative method(TIM)