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Bilateral Coupled Epsilon Negative Metamaterial for Dual Band Wireless Communications

Computers, Materials & Continua 2022年第4期71卷 1263-1281页

作者： md Mhedi Hasan Mohammad Tariqul Islam md Moniruzzaman Mohd Hafiz Uddin Norsuzlin Binti Mohd Sahar md Samsuzzaman Department of Electrical Electronic and Systems Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan MalaysiaSelangor43600Malaysia Space Science Centre Institute of Climate ChangeUniversiti Kebangsaan MalaysiaSelangor43600Malaysia Department of Computer and Communication Engineering Faculty of Computer Science and EngineeringPatuakhali Science and Technology UniversityPatuakhali8602Bangladesh

This work presents a dual band epsilon negative(ENG)metamaterial with a bilateral coupled split ring resonator(SRR)for use in C and X band wireless communication *** traditional split-ring resonator(SRR)has been amended with this engineered *** proposed metamaterial unit cell is realized on the 1.6 mm thick FR-4 printed media with a dimension of 10×10 *** resonating patch built with a square split outer *** interlinked inner rings are coupled vertically to the outer ring to extend its electrical length as well as to tune the resonance *** simulation is performed using CST studio suite 2019 to design and performance *** transmission coefficient(S21)of the proposed unit cell and array configuration exhibits two resonances at 6.7 and 10.5 GHz with wide bandwidth extended from 4.86 to 8.06 GHz and 10.1 to 11.2 GHz,*** permittivity is noted at frequencies between 6.76–9.5 GHz and 10.5–12 GHz,consecutively,with near-zero refractive index and *** optimal EMR value depicts the compactness of the proposed *** 1×2,2×2 and 4×4 arrays are analyzed that shows similar response compared to the unit *** results of the 2×2 array shows the close similarity of S21 response as compared to *** observed properties of the proposed unit cell ascertain its suitability for wireless communications by enhancing the gain and directivity of the antenna system.

关键词： Metamaterial epsilon negative near-zero index split ring resonator wireless communications

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Influence of dielectric barrier discharge treatment on mechanical and dyeing properties of wool

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Plasma Science and Technology 2018年第6期20卷 89-98页

作者： Rahul NAVIK Sameera SHAFI md Miskatul ALAM md Amjad FAROOQ Lina LIN Yingjie CAI Hubei Provincial Engineering Laboratory for Clean Production and High Value Utilization of Bio-Based Textile Materials Wuhan Textile UniversityWuhan 430073People＇s Republic of China School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240People＇s Republic of China

Physical and chemical properties of wool surface significantly affect the absorbency,rate of dye bath exhaustion and fixation of the industrial ***,surface modification is a necessary operation prior to coloration process in wool wet processing *** treatment is an effective alternative for physiochemical modification of wool ***,optimum processing parameters to get the expected modification are still under investigation,hence this technology is still under development in the wool wet processing ***,in this paper,treatment parameters with the help of simple dielectric barrier discharge plasma reactor and air as a plasma gas,which could be a promising combination for treatment of wool substrate at industrial scale were schematically studied,and their influence on the water absorbency,mechanical,and dyeing properties of twill woven wool fabric samples are *** is expected that the results will assist to the wool coloration industries to improve the dyeing processes.

关键词： air plasma reactive dye surface energy wool

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Improved voltage tracking of autonomous microgrid technology using a combined resonant controller with lead-lag compensator adopting negative imaginary theorem

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Protection and Control of Modern Power Systems 2022年第1期7卷 149-164页

作者： md.Yah-Ya Ul Haque md.Rashidul Islam Tanvir Ahmed md.Rafiqul Islam Sheikh Department of Electrical and Electronic Engineering Varendra UniversityRajshahi 6204Bangladesh Department of Electrical and Electronic Engineering Rajshahi University of Engineering&TechnologyRajshahi 6204Bangladesh

Growing application of distributed generation units at remote places has led to the evolution of microgrid(MG)*** an MG system functions independently,i.e.,in autonomous mode,unpredictable loads and uncertainties emerge throughout the *** obtain stable and flexible operation of an autonomous MG,a rigid control mechanism is *** this paper,a robust high-performance controller is introduced to improve the performance of voltage tracking of an MG system and to eliminate stability problems.A combination of a resonant controller and a lead-lag compensator in a positive position feedback path is designed,one which obeys the negative imaginary(NI)theorem,for both single-phase and three-phase autonomous MG *** controller has excellent tracking *** is investigated through considering various uncertainties with different load *** feasibility and effectiveness of the controller are also determined with a comparative analysis with some well-known controllers,such as linear quadratic regulator,model predictive and NI approached resonant *** confirms the superi-ority of the designed controller.

关键词： Negative imaginary theorem Resonant controller Lead-lag compensator Autonomous microgrid Voltage tracking

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Optimizing the Global Digital Elevation Models(GDEMs) and accuracy of derived DEMs from GPS points for Iraq’s mountainous areas

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Geodesy and Geodynamics 2020年第5期11卷 338-349页

作者： Shazad Jamal Jalal Tajul Ariffin Musa Taher Hama Ameen Ami hassan md Din Wan Anom Wan Aris Jwan Mohammad Ebrahim Faculty of Built Environment and Surveying Universiti Teknologi Malaysia Johor Bahru 81310 Malaysia College of Engineering University of Sulaimani 46001 Sulaimani Iraq University of Arkansas at Little Rock Little Rock 72204 AR USA SALP Middle East Ltd. Company for Oil and Gas Pipeline Construction Erbil Iraq

Optimizing the combined horizontal and vertical accuracy of the well-known Global Digital Elevation Models(GDEMs) of various resolutions for each country and region especially in Iraq’s mountainous areas is still questionable. All the three GDEMs, approximately, have the same vertical accuracy with the Root Mean Square(RMSE) of ±7.3 m, ±7.6 m and ±6.5 m via 12 fixed Ground Control Points(GCPs) for the Advanced Land Observation Satellite Phased Array L-band Synthetic Aperture Radar(ALOS PALSAR 12.5 m), the Shuttle Radar Topographic Mission(SRTM 30 m) and the TerraSAR-X(the name of twin satellites) add-on for Digital Elevation Measurement(TanDEM-X 90 m) GDEMs respectively. Moreover, the percentage of outliers that are greater or smaller than ±10 m detection of the height extraction from both the ALOS PALSAR and SRTM Digital Elevation Models(DEMs) contains 16.7% and for TanDEM-X was 25%. In this paper,the special DEM is derived using 2123 handheld GPS points for Sulaymaniyah Governorate, Kurdistan region, Iraq. The height extraction by discarding the outliers of 58% gives the RMSE of ±8.0 m in the case of adding geoid heights(N) to the ellipsoidal heights(h) via the Earth Gravitational Model 2008(EGM2008)and ±5.6 m without adding N. It is expected that the derived DEMs will give more accurate results both horizontally and vertically in the mountainous areas when GPS observations are intensified. The horizontal accuracy is validated through extracting hierarchy stream types of the watershed map from the DEMs for higher than 100 pixels length. The ALOS PALSAR DEM extracted more numbers of stream orders than ***, based on the criteria of RMSE, outlier detection, and the number of extracted stream orders, the ALOS PALSER DEM is regarded as the optimal GDEM in comparison with the close accuracy of both the TanDEM-X and SRTM DEM.

关键词： EGM2008 PALSAR SRTM

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Solution processed high performance perovskite quantum dots/ZnO phototransistors

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Nano Research 2022年第4期15卷 3660-3666页

作者： md Mehedi Hasan Eric Moyen Jewel Kumer Saha md Mobaidul Islam Arqum Ali Jin Jang Advanced Display Research Center(ADRC) Department of Information DisplayKyung Hee University26Kyungheedae-roDongdaemun-guSeoul 02447Republic of Korea

Phototransistors that can detect visible light have been fabricated using solution processed zinc oxide channel/zirconium oxide gate insulator thin film transistors(TFTs)and room temperature synthesized perovskite quantum dots(PeQDs)as active *** ZnO thin film transistors did not show a photocurrent under visible light ***,ZnO TFTs decorated with PeQDs exhibited enhanced photocurrent upon exposure to visible *** device had a responsivity of 567 A/W(617 A/W),a high detectivity of 6.59×10^(13)Jones(1.85×10^(14)J)and a high sensitivity of 10^(7)(10^(8))under green(blue)light at a low drain voltage of 0.1 *** high photo-responsivity and detectivity under green light resulted from the combination of short ligands in the QDs films and the high mobility of the spray coated ZnO *** results are relevant for the development of low cost and low energy consumption phototransistors working in the visible range.

关键词： ZnO thin film transistors perovskite quantum dots photo-detectors photo-transistors

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Measurement and correlation of solubility of diosmin in four pure solvents and β-cyclodextrin solution at 298.15K to 333.15K

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Chinese Journal of Chemical Engineering 2015年第5期23卷 812-815页

作者： md Khalid Anwer Faiyaz Shakeel Department of Pharmaceutics College of Pharmacy Salman Bin Abdulaziz University Center of Excellence in Biotechnology Research King Saud University Department of Pharmaceutics College of Pharmacy King Saud University

The aim of present study was to measure and correlate the solubility of poorly water-soluble flavonoid diosmin in water, ethanol, isopropyl alcohol （IPA）, polyethylene glycol-400 （PEG-400） and β-cyclodextrin （β-CD） aqueous solution （0.02 mol·L^-1 ）. The solubility of diosmio was measured using the shake flask method from （298.15 to 333.15） K at atmospheric pressure. The experimental solubilities of diosmin were regressed by the modified Apelblat model with a relative deviation in the range of 0.048% to 5.940%. The correlation coefficients were observed in the range of 0.9957 to 0.9995. The solubility of diosmin was found to be increased with temperature in all sample matrices investigated. The mole fraction solubility of diosmin was found to be higher in 5-CD aqueous solution and PEG-400 as compared to water, ethanol and IPA. Based on solubility data of present study, diosmin was considered as practically insoluble in water, insoluble in ethanol ＆ IPA and soluble in PEG- 400 and β-CD aqueous solution.

关键词： Apelblat model Cyclodextrin Diosmin Solubility Thermodynamics

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Investigation of phase-change materials for interior temperature regulation in public transport

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Clean Energy 2022年第1期6卷 178-192页

作者： md Nahidul Islam md Nahid Hossain Dewan HasanAhmed Department of Mechanical and Production Engineering Ahsanullah University of Science and Technology141-142 Love RoadTejgaon Industrial AreaDhakaBangladesh

Regulating the indoor temperature of public transport on hot sunny days is a prime concern,as both the external and internal heat sources play an active role in heat *** studies have been carried out on a bus model using sodium sulphate decahydrate as a phase-change material(PCM)that is placed in between the ceiling and the *** are conducted on a sunny day and also for different cases of external(300-W surface heater)and internal(25-W light bulb)heat *** results show that PCM,in the presence of an external heat source,can help to keep the indoor temperature lower and delay the time period for increasing the temperature by absorbing heat during the phase *** the other hand,the presence of the internal heat source contributes to a detrimental effect on the indoor temperature,which gradually increases with the elapse of *** the combination of the external and internal heat sources,it is found that the internal heat source plays a dominating factor to raise the indoor *** is revealed from the experimental results that a 12.7-mm single layer and a single PCM are not enough to counter the internal heat of 25 W unless the thickness of the PCM layer is increased to delay the increase in the indoor *** additional PCM layer with a lower melting temperature could be placed at the inner portion of the ceiling to have effective thermal-energy storage by absorbing the substantial heat gain from the internal heat sources.

关键词： latent heat sodium sulphate decahydrate phase-change material transportation thermal-energy storage

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Design and Optimization of Actuator for HT-25 Multifunctional Loader

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World Journal of Engineering and Technology 2023年第4期11卷 874-892页

作者： md. Al Imran Tapu Joy Howlader md. Shahriar Sujan md. Jahangir Alam md. Mehedi hassan College of Harbor Coastal & Offshore Engineering Hohai University Nanjing China Department of Computer Science and Technology College of Computer and Information Hohai University Nanjing China College of Civil and Transportation Engineering Hohai University Nanjing China Department of Information Communication Engineering College of Internet of Things Hohai University Nanjing China

To break down the development interaction of the working gadget of the multi-practical wheel loader and to compute the heap of each part, the Denavit-Hartenberg strategy was applied to build up the kinematics of the instrument model. Also, all the while, set up the elements model of dynamic framework. A multi-body element programming MSC, ADAMS and its active module were applied to assemble component power through a pressure framework reenactment model. An entirety working cycle interaction of the functioning gadget of the wheel loader was mimicked, and the investigation results thoroughly show the development interaction of the functional device and the stacked state of each part, and check the mechanical properties of the working gadget and dynamic execution water-driven framework effectively.

关键词： Multifunctional Loader Hydraulic Circuit CAD Power System Hydraulic Actuator and Pump

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quantum gases power law potential grand potential condensation hierarchy

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Communications in Theoretical Physics 2016年第2期65卷 169-176页

作者： Mir Mehedi Faruk md.Sazzad Hossain md.Muktadir Rahman Department of Theoretical Physics University of Dhaka Dhaka-lO00 Bangladesh Theoretical Physics Blackett Laboratory Imperial College London SW7 2AZ United Kingdom Department of Nuclear Engineering University of Dhaka Dhaka-1000 Bangladesh

The changes in characteristics of Bose condensation of ideal Bose gas due to an external generic power law potential U =∑~d_（i=1）ci｜xi/ai｜~（ni） are studied carefully. Detailed calculation of Kim et al.（J. Phys. Condens. Matter 11（1999） 10269） yielded the hierarchy of condensation transitions with changing fractional dimensionality. In this manuscript, some theorems regarding specific heat at constant volume CV are presented. Careful examination of these theorems reveal the existence of hidden hierarchy of the condensation transition in trapped systems as well.

关键词： Investigation of Bose Condensation in Ideal Bose Gas Trapped under Generic Power Law Potential in d Dimension

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Test and performance optimization of nozzle inclination angle and swirl combustor in a low-tar biomass gasifier:a biomass power generation system perspective

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Carbon Resources Conversion 2022年第2期5卷 139-149页

作者： md Mashiur Rahman Agricultural Engineering Division Regional Agricultural Research StationBangladesh Agricultural Research InstituteJamalpur2000Bangladesh DTU Chemical Engineering Technical University of Denmark(DTU)Frederiksborgvej 399DK 4000 RoskildeDenmark

A nozzle inclination angle and swirl combustor inside the low-tar biomass(LTB)gasifier reactor were tested and optimized to evaluate these effects on tar reduction to design tar-free producer *** tar reduction process is mainly based on the concept of a swirling flow created by the nozzle inclination angle,with the inclination angle of 55◦to the radial line,allowing good mixing between pyrolysis gases and gasifying agents.A separate swirl combustor has created large internal annular and reverses flow zones with the help of swirl flow,resulting in homogenized temperature inside the combustor and providing longer residence time;both have a positive effect on the combustion of mixed gasifying air-pyrolysis gases by the thermal cracking in the partial oxidation *** ratio(RR)and combustion degree of volatiles are the two optimization parameters for evaluating the performance of NIA and swirl *** result observed that outstanding tar reduction occurred in this novel *** 86.5 and 12.8%of tar compounds are broken down in the partial oxidation zone and pyrolysis zone using the novel swirl combustor and NIA,respectively;gas outlet has observed producer gas having tar concentration of less than 1%.The optimization results reveal that a lower recycling ratio(recycle gas/gasifying air)and a higher combustion degree of volatiles perform better in biomass ***,this system generated producer gas with the tar concentration at an extremely low level of 7.4 mg/Nm^(3)for a biomass moisture content of 9%and appeared the lower heating value of 4.6–5.1 MJ/Nm^(3).This lower tar concentration might be directly coupled with an internal combustion engine or a gas turbine for power generation.

关键词： Biomass gasification Downdraft moving bed gasifier Nozzle inclination angle Swirl combustor Swirl flow Tar Reduction

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