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Fabrication of Bi_2O_3/TiO_2nanocomposites and their applications to the degradation of pollutants in air and water under visible-light

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Journal of Environmental Sciences 2014年第2期26卷 458-465页

作者： Ashok Kumar Chakraborty md Emran Hossain md Masudur Rhaman K M A Sobahan Department of Applied Chemistry and Chemical Technology Islamic University Department of Applied Physics Electronics and Communication Engineering Islamic University

A nanoheterojunction composite photocatalyst Bi2O3/TiO2 working under visible-light （λ≥ 420 nm） was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2 molar ratio. Maleic acid was employed as an organic binder to unite Bi2O3 and TiO2 nanoparticles. The SEM, TEM, XRD and diffuse reflectance spectra were utilized to characterize the prepared Bi2O3/TiO2 nanoheterojunction. The nanocomposite exhibited unusual high photocatalytic activity in decomposing 2-propanol in gas phase and phenol in aqueous phase and, evolution of CO2 under visible light irradiation while the end members exhibited low photocatalytic activity. The composite was optimized to 5 mol% Bi2O3/TiO2. The remarkable high photocatalytic efficiency originates from the unique relative energy band position of Bi2O3 and TiO2 as well as the absorption of visible light by Bi2O3.

关键词： nanoheterojunction Bi2O3/TiO2 composite photocatalyst pollutants visible-light

Surface settlement induced by horizontal directional drilling

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Underground Space 2023年第1期8卷 94-108页

作者： Asif Ahmed md Azijul Islam md Zahangir Alam Hashmi S.Quazi College of Engineering State University of New York Polytechnic Institute(SUNY Poly)UticaNY 13502USA Department of Civil Engineering The University of Texas at ArlingtonArlingtonTX 76019USA Department of Civil Engineering Bangladesh University of Engineering and Technology(BUET)Dhaka 1000Bangladesh Converse Consultants RedlandsCA 92373USA

Horizontal directional drilling(HDD)is a widely used trenchless method for underground utility *** associated ground settlement triggered by HDD depends on the size,types,and surface texture of pipe,diameter of borehole,and soil *** pre-sent study investigates the surface settlement due to the construction of a 1067 mm diameter HDD,which will replace an existing sewer siphon under the SR-60 highway in Chino,California using empirical,and numerical *** on the results obtained from the subsurface investigation,an empirical analysis was conducted *** by numerical modeling of the HDD using PLAXIS 2D soft-ware.A careful comparison between two different methods indicated closer values of surface settlement between the empirical method(7.3 mm)and the numerical modeling(4.6 mm).In addition,the shape of surface settlement and horizontal settlement curves for the empirical and numerical methods was found to be *** minor discrepancy between the two methods resulted as the numerical model can host several soil layers whereas the empirical equation can use only one type of ***,a parametric study was conducted to evaluate the effect of borehole cover depth,size,and soil parameters on surface *** was observed that soil strength param-eters yielded a greater effect on surface movement,whereas modulus of elasticity has a relatively smaller influence with zero contribution from Poisson’s ratio.

关键词： Horizontal directional drilling(HDD) Surface settlement Cover depth Soil arching Borehole

An approach to Iocational marginal price based zonal congestion management in deregulated electricity market

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Frontiers in Energy 2016年第2期10卷 240-248页

作者： md SARWAR Anwar Shahzad SIDDIQUI Department of Electrical Engineering Jamia Millia Islamia (A Central University) New Delhi 110025 India

Congestion of transmission line is a vital issue and its management pose a technical challenge in power system deregulation. Congestion occurs in deregulated electricity market when transmission capacity is not sufficient to simultaneously accommodate all constraints of power transmission through a line. Therefore, to manage congestion, a locational marginal price （LMP） based zonal congestion management approach in a deregulated elec- tricity market has been proposed in this paper. As LMP is an economic indicator and its difference between two buses across a transmission line provides the measure of the degree of congestion, therefore, it is efficiently and reliably used in deregulated electricity market for conges- tion management. This paper utilizes the difference of LMP across a transmission line to categorize various congestion zones in the system. After the identification of congestion zones, distributed generation is optimally placed in most congestion sensitive zones using LMP difference in order to manage congestion. The performance of the proposed methodology has been tested on the IEEE 14-bus system and IEEE 57-bus system.

关键词： locational marginal price (LMP) distributed generation pool market deregulated electricity market,congestion management

Energy efficiency aware dynamic rate and power adaptation in carrier sensing based WLANs under Rayleigh fading and shadowing

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Digital Communications and Networks 2024年第4期10卷 918-933页

作者： md.Forkan Uddin Department of Electrical and Electronic Engineering Bangladesh University of Engineering and TechnologyDhaka1205Bangladesh

We consider the problem of energy efficiency aware dynamic adaptation of data transmission rate and transmission power of the users in carrier sensing based Wireless Local Area Networks(WLANs)in the presence of path loss,Rayleigh fading and log-normal *** a data packet transmission,we formulate an optimization problem,solve the problem,and propose a rate and transmission power adaptation scheme with a restriction methodology of data packet transmission for achieving the optimal energy *** the restriction methodology of data packet transmission,a user does not transmit a data packet if the instantaneous channel gain of the user is lower than a *** evaluate the performance of the proposed scheme,we develop analytical models for computing the throughput and energy efficiency of WLANs under the proposed scheme considering a saturation traffic *** then validate the analytical models via *** find that the proposed scheme provides better throughput and energy efficiency with acceptable throughput fairness if the restriction methodology of data packet transmission is *** means of the analytical models and simulations,we demonstrate that the proposed scheme provides significantly higher throughput,energy efficiency and fairness index than a traditional non-adaptive scheme and an existing most relevant adaptive *** and energy efficiency gains obtained by the proposed scheme with respect to the existing adapting scheme are about 75%and 103%,respectively,for a fairness index of *** also study the effect of various system parameters on throughput and energy efficiency and provide various engineering insights.

关键词： Carrier sense multiple access Energy efficiency Fading and shadowing Rate and power adaptation Throughput Wireless local area networks

Sensitivity analysis of the DehumReq model to evaluate the impact of predominant factors on dehumidification requirement of greenhouses in cold regions

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Information Processing in Agriculture 2023年第2期10卷 216-228页

作者： md Sazan Rahman Huiqing Guo Department of Mechanical Engineering University of Saskatchewan57 Campus driveSaskatoonSK S7N 5A9Canada Department of Bioresource Engineering McGill UniversityMacdonald Stewart Building21111 Lakeshore RoadSainte-Anne-de-BellevueQC H9X 3V9Canada

In this study,the sensitivity of a novel dehumidification requirement model(DehumReq)is analyzed to evaluate the effect of the predominant factors on the dehumidification needs of the *** hourly dehumidification demand and sensitivity coefficient(SC)are estimated for three different seasons:warm(July),mild(May),and cold(November),by using the local sensitivity analysis *** on SC values,the solar radiation,air exchange,leaf area index(LAI),and indoor setpoints(temperature,relative humidity(RH),and water vapor partial pressure(WVPP))have significant impact on the dehumidifi-cation needs,and the impact varies from season to *** parameters have a higher SC in summer,whereas solar radiation and LAI have a higher SC in mild *** dehumidification load increases 4 times of its base value with increasing solar radiation by 200 W/m^(2),and the highest LAI(10)caused 5 times increment of the *** changing of WVPP from its base value(1.5 kPa)to maximum(2.9 kPa)reduces the load 70%in *** exchange was found to be the most crucial parameter because it is the main dehumidification approach that has a large range and is easily adjustable for any *** air exchange by ventilation or infiltration will reduce the dehumidification load to zero in May and November and minimizes it to only nighttime load in *** the other parameters,higher ambient air RH and indoor air speed will result in higher the dehumidification load;whereas higher inner surface condensation will result in lower dehumidifi-cation *** result of this study will assist in the selection of the most efficient moisture control strategies and techniques for greenhouse humidity control.

关键词： Greenhouse Dehumidification DehumReq model Sensitivity analysis Solar radiation Air exchange

Design of a Simple Integrated Coupler for SPP Excitation in a Dielectric Coated Ag Thin Film

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Chinese Physics Letters 2014年第6期31卷 94-97页

作者： Rakibul Hasan Sagor md. Ruhul Amin md. Ghulam Saber Department of Electrical and Electronic Engineering Islamic University of Technology Board Bazar Gazipur-1704 Bangladesh

A simple integrated coupler is proposed for the efficient excitation of surface plasmon polariton （SPP） mode in a thin metal film. The SPP mode is generated in a single Ag-dielectric interface by the incident field and coupled with an Ag thin film. The coupling efficiency at different wavelengths using two different dielectrics, gallium lanthanum sulfide （GLS） and aluminum gallium arsenide （AIGaAs） is calculated by analyzing the SPP propagation dynamics with the finite difference time domain method. A maximum coupling efficiency of 70~ is obtained at a wavelength of 46Ohm when GLS is used, whereas the corresponding value obtained for A1GaAs is 60~o at 56Onto. The proposed structure can be used to excite SPPs in a nano-thin film from an external bulky source and is easier to fabricate since a single interface metal-dielectric configuration is used to excite the metal-thin film.

关键词： ELECTRIC insulators & insulation NUMERICAL analysis SURFACE coatings NUCLEAR excitation EXCITATION spectrum POLARITONS SURFACE plasmons

A Comparative Study of Dispersion Characteristics Determination of a Trapezoidally Corrugated Slow Wave Structure Using Different Techniques

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Chinese Physics Letters 2016年第1期33卷 132-135页

作者： md.Ghulam Saber Rakibul Hasan Sagor md.Ruhul Amin Department of Electrical and Electronic Engineering Islamic University of Technology

The linear dispersion relation of a trapezoidally corrugated slow wave structure （TCSWS） is analyzed and presented. The size parameters of the TCSWS are chosen in such a way that they operate in the x-band frequency range. The dispersion relation is solved by utilizing the Rayleigh-Fourier method by expressing the radial function in terms of the Fourier series. A highly accurate synthetic technique is also applied to determine the complete dispersion characteristics from experimentally measured resonances （cold test）. Periodic structures resonate at specific frequencies when the terminals are shorted numerical calculation, synthetic technique and cold appropriately. The dispersion characteristics obtained from test are compared, and an excellent agreement is achieved.

关键词： of on A Comparative Study of Dispersion Characteristics Determination of a Trapezoidally Corrugated Slow Wave Structure Using Different Techniques in been is

Proton conductivity performance and its correlation with physiochemical properties of proton exchange membrane(PEM)

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Chinese Journal of Chemical Engineering 2024年第10期74卷 100-116页

作者： Mirza Nusrat Sweety md Abdus Salam Hydrogen Energy Laboratory Bangladesh Council of Scientific and Industrial Research(BCSIR)Chattogram 4220Bangladesh Institute of Mining Mineralogy and Metallurgy(IMMM)BCSIRJoypurhat 5900Bangladesh BCSIR Dhaka Laboratories Dhaka 1205Bangladesh

Graphene oxide(GO)filler containing diversified Nafion-based proton exchange membrane(PEM)is studied to know the unique physical and chemical properties and performances of ***-SPEEK 1%-GO 0.75%(NSG-0.75%)composite shows the highest proton conductivity of 0.327 S·cm^(-1) at 90℃ and 100%RH(relative humidity)among all the PEM *** descending order of significant proton conductivity is found as;Nafion-sPGO(1%)0.306 S·cm^(-1)>Nafion/ZIF-8@GO 0.280 S·cm^(-1)>Nafion/PGO(2%)0.277 S·cm^(-1)>Nafion/GO-sulfur(3%)0.232 S·cm^(-1)>Nafion/GO-poly-SPM-co-PEGMEMA(1%)0.229 S·cm^(-1)>Nafion/Ce-sPGO(1%)0.215 S·cm^(-1).The proton conductivity,water uptake capacity and ion exchange capacity,hydration number,thermal and oxidative stability,mechanical integrity(tensile strength),maximum power,and current density are found to be increased while activation energy and fuel crossover show a decrement as GO or modified GO is incorporated in the Nafion *** component analysis(PCA)predicted a significant correlation between the proton conductivity and the properties;the water uptake capacity,ion exchange capacity,hydration number,maximum power density,and maximum current density are 0.598%,0.688%,0.894%,0.980%,and 0.852%accordingly.A multiple linear model equation of proton conductivity is defined with the parameters of water uptake capacity,ion exchange capacity,hydration number,maximum power density,and maximum current density whereas the regression coefficient is 0.9923.

关键词： Fuel cells Membranes Nafion GO-filler Proton conductivity Principal component analysis

Stature estimation from footprint measurements in Bangladeshi adults

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Forensic Sciences Research 2022年第2期7卷 124-131页

作者： md Asadujjaman md Harun Or Rashid md Sohel Rana md Mosharraf Hossain Department of Industrial&Production Engineering Rajshahi University of Engineering&TechnologyRajshahiBangladesh

The estimation of stature is very important in forensic investigation,as it provides useful data that can narrow the pool of potentially matching *** purpose of this study was to develop formulae for the estimation of stature from footprint measurements in Bangladeshi *** study included 118 randomly selected men and 130 randomly selected women,all aged 18–50 *** each participant,stature and six footprint measurements were taken by means of standard measurement *** measurements were found to be positively correlated with *** was estimated by using linear regression *** right T1 length in men(R:þ0.587,R^(2):0.345)and the right T2 length in women(R:þ0.506,R^(2):0.256)were the most reliable individual estimators of ***,when data were combined for both sexes,the right T2 length was identified as the most reliable estimator of stature,with higher values of R(þ0.792)and R^(2)(0.627).In conclusion,human stature can be successfully estimated by using footprint measurements;this finding can be applied in forensic research and investigation.

关键词： Forensic sciences forensic anthropology anthropometry footprint stature estimation forensic identification