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Journal of Thermal Science 2007年第2期16卷 134-139页

作者： Shigeru MATSUO Kenbu TERAMOTO Miah md.Ashraful alam Toshiaki SETOGUCHI Heuy Dong KIM Shen YU Department of Mechanical Engineering Saga University1Honjo-machiSaga-shiSaga 840-8502Japan Department of Mechanical Engineering Khulna University of Engineering & TechnologyKhulna-9203Bangladesh School of Mechanical Engineering Andong National University388Songchun-dongAndong 760749Korea Institute of Engineering Thermophysics Chinese Academy of SciencesP.O.Box 2706Beijing 100080China

The unsteady phenomena in the transonic flow around airfoils are observed in the flow field of fan, compressor blades and butterfly valves, and this often causes serious problems such as the aeroacoustic noise, the vibration. In the transonic or supersonic flow where vapour is contained in the main flow, the rapid expansion of the flow may give rise to a non-equilibrium condensation. However, the effect of non-equilibrium condensation on the transonic internal flows around the airfoil has not yet been clarified satisfactorily. In the present study, the effect of non-equilibrium condensation of moist air on the self-excited shock wave oscillation on a circular arc blade was investigated numerically. The results showed that in the case with non-equilibrium condensation, frequencies of the flow oscillation became smaller than those without the non-equilibrium condensation.

关键词： compressible flow transonic flow shock wave oscillation non-equilibrium condensation simulation

Enhancement of Growth and Grain Yield of Rice in Nutrient Deficient Soils by Rice Probiotic Bacteria

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Rice science 2017年第5期24卷 264-273页

作者： md Mohibul alam KHAN Effi HAQUE Narayan Chandra PAUL md Abdul KHALEQUE Saleh M. S. AL-GARNI Mahfuzur RAHMAN md Tofazzal ISLAM Department of Biotechnology Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur 1706 Bangladesh Department of Biochemistry & Microbiology North South University Dhaka 1229 Bangladesh Department of Rural Development Administration Bioenergy Crop Research Institute Muan 534833 Republic of Korea Department of Biological Sciences King Abdulaziz University Jeddah 2589 Kingdom of Saudi Arabia West Virginia University Morgantown West Virginia 26505 USA

Plant associated bacteria are promising alternatives to chemical fertilizers for plant growth and yield improvement in an eco-friendly *** this study,rice associated bacteria were isolated and assessed for mineral phosphate solubilization and indole-3-acetic acid(IAA) production activity in *** promising strains,which were tentatively identified as phylotaxon Pseudochrobactrum sp.(BRRh-1),Burkholderia sp.(BRRh-2),Burkholderia sp.(BRRh-3),Burkholderia sp.(BRRh-4),Pseudomonas aeruginosa(BRRh-5 and BRRh-6) based on their 16 S rRNA gene phylogeny,exhibited significant phosphate solubilizing activity in National Botanical Research Institute phosphate growth medium,and BRRh-4 displayed the highest phosphate solubilizing activity,followed by *** p H of the culture broth declined,resulting in increase of growth rate of bacteria at p H 7,which might be due to organic acid secretion by the *** presence of L-tryptophan,five isolates synthesized IAA and the maximum IAA was produced by BRRh-2,followed by *** of two most efficient phosphate solubilizing isolates BRRh-4 and BRRh-5 by root dipping(colonization) of seedling and spraying at the flowering stage significantly enhanced the growth and grain yield of rice variety BRRI ***,application of both strains with 50% of recommended nitrogen,phosphorus and potassium fertilizers produced equivalent or higher grain yield of rice compared to the control grown with full recommended fertilizer doses,which suggests that these strains may have the potential to be used as bioinoculants for sustainable rice production.

关键词： indole-3-acetic acid mineral phosphate solubilization rice plant growth promotion plant associated bacterium grain yield fertilizer

Design and Optimization of Photonic Crystal Fiber Based Sensor for Gas Condensate and Air Pollution Monitoring

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Photonic Sensors 2017年第3期7卷 234-245页

作者： md. Ibadul ISLAM Kawsar AHMED Shuvo SEN Sawrab CHOWDHURY Bikash Kumar PAUL md. Shadidul ISLAM Mohammad Badrul alam MIAH Sayed ASADUZZAMAN Department of Information and Communication Technology (ICT) Mawlana Bhashani Science and Technology University Santosh Tangail 1902 Bangladesh Group of Bio-photomatix Tangail 1902 Bangladesh Department of Software Engineering (SWE) Daffodil International University Sukrabad Dhaka 1207 Bangladesh

In this paper, a hexagonal shape photonic crystal fiber （H-PCF） has been proposed as a gas sensor of which both micro-structured core and cladding are organized by circular air cavities. The reported H-PCF has a single layer circular core which is surrounded by a five-layer hexagonal cladding. The overall pretending process of the H-PCF is completed by using a full vectorial finite element method （FEM） with perfectly matched layer （PML） boundary condition. All geometrical parameters like diameters and pitches of both core and cladding regions have fluctuated with an optimized structure. After completing the numerical analysis, it is clearly visualized that the proposed H-PCF exhibits high sensitivity with low confinement loss. The investigated results reveal the relative sensitivity of 56.65% and confinement loss of 2.31×10^-5 dB/m at the 1.33%tm wavelength. Moreover, effective area, nonlinearity, and V-parameter of the suggested PCF are also briefly described.

关键词： Relative sensitivity confinement loss gas sensor effective area nonlinearity and photonic crystal fiber

An Efficient Approach for Transforming Unbalanced Transportation Problems into Balanced Problems in Order to Find Optimal Solutions

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American Journal of Operations Research 2024年第1期14卷 74-86页

作者： Abdur Rashid md. amirul Islam Department of Mathematics Jahangirnagar University Dhaka Bangladesh Department of Mathematics Uttara University Dhaka Bangladesh

In operations research, the transportation problem (TP) is among the earliest and most effective applications of the linear programming problem. Unbalanced transportation problems reflect the reality of supply chain and logistics situations where the available supply of goods may not precisely match the demand at different locations. To deal with an unbalanced transportation problem (UTP), it is essential first to convert it into a balanced transportation problem (BTP) to find an initial basic feasible solution (IBFS) and hence the optimal solution. The present paper is concerned with introducing a new approach to convert an unbalanced transportation problem into a balanced one and as a consequence to obtain optimum total transportation cost. Numerical examples are provided to demonstrate the suggested method.

关键词： Unbalanced Transportation Problem (UTP) Supply Demand Initial Solution Optimal Solution

Effect of workplace violence on health workers injuries and workplace absenteeism in Bangladesh

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Global Health Research and Policy 2023年第1期8卷 201-211页

作者： md.Shahjalal mdParvez Mosharaf Rashidul alam Mahumud Global Health Institute North South UniversityDhakaBangladesh Department of Public Health North South UniversityDhakaBangladesh Research Rats DhakaBangladesh School of Business and Centre for Health Research University of Southern QueenslandToowoombaQLDAustralia Health Economics and Health Technology Assessment Unit NHMRC Clinical Trials CentreFaculty of Medicine and HealthThe University of SydneyCamperdownNSWAustralia

Background Workplace violence(WPV)is an emerging problem for health workers(HWs)and a global concern in health *** literatures infer that WPV against HWs is often attributed to workplace injuries and absenteeism,leading to a series of adverse ***,this study aimed to investigate the prevalence of workplace injuries and absenteeism due to WPV among Bangladeshi HWs and its association with factors related to health facilities,work environments,and rotating shift *** This study used participants who had experienced WPV,including medical doctors,nurses,or any form of medical staff.A total of 468 victim HWs were added in the analytical *** were generated from our previous cross-sectional study of 1081 Bangladeshi HWs.A logistic regression model was used to find the association between workplace injuries and absenteeism due to WPV among HWs and associated *** The prevalence of workplace injuries and absenteeism due to WPV among HWs were 14.10%(95%CI 11.23-7.57)and 22.44%(95%CI 18.87-26.45),*** incidence was higher among males(17.67%)and young HWs(20.83%).Workplace absenteeism was more common among male HWs(25%)and those working in public hospitals(23.46%).The magnitude of injuries and absenteeism varied significantly by hospital *** injury was significantly higher among HWs who worked in the emergency(AOR=21.53,95%CI 2.55-181.71),intensive care(AOR=22.94,95%CI 2.24-234.88),surgery(AOR=17.22,95%CI 1.96-151.39),and gynecology&obstetrics departments(AOR=22.42,95%CI 2.25-223.07)compared with other *** burden of work-related absenteeism was significantly associated with HWs who worked in the emergency(AOR=4.44,95%CI 1.56-12.61),surgery(AOR=4.11,95%CI 1.42-11.90),and gynecology and obstetrics departments(AOR=5.08,95%CI 1.47-17.50).Conclusions This study observed a high prevalence of workplace injuries and absenteeism among HWs due to WPV across hospital depar

关键词： Workplace violence Health workers Injury Absenteeism Bangladesh

Interaction of cetyltrimethylammonium bromide with drug in aqueous/electrolyte solution:A combined conductometric and molecular dynamics method study

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Chinese Journal of Chemical Engineering 2018年第1期26卷 159-167页

作者： md.Anamul Hoque md.Masud alam Mohammad Robel Molla Shahed Rana Malik Abdul Rub Mohammad A.Halim Mohammed Abdullah Khan Farida Akhtar Department of Chemistry Jahangirnagar UniversitySavarDhaka 1342Bangladesh Chemistry Department Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia Center of Excellence for Advanced Materials Research King Abdulaziz UniversityJeddah 21589Saudi Arabia Division of Quantum Chemistry BICCBThe Red-Green Computing Centre218 Elephant RoadDhaka 1205Bangladesh Institut Lumière Matière Université Lyon 1-CNRSUniversitéde Lyon69622 Villeurbanne CedexFrance

Interaction between beta-lactum antibiotic drug ciprofloxacin hydrochloride(CFH)and cationic surfactant cetyltrimethylammonium bromide(CTAB)was performed conductometrically in aqueous as well as in the occurrence of different salts(NaCl,KCl as well as NH_4Cl)over the temperature range of 298.15–323.15 K at the regular interval of 5 *** drug has been suggested for the treatment of bacterial infections such as urinary tract infections and acute sinusitis.A clear critical micelle concentration(CMC)was obtained for pure CTAB as well as(CFH+CTAB)mixed *** decrease in CMC values of CTAB caused by the addition of CFH reveals the existence of the interaction between the components and therefore it is the indication of micelle formation at lower concentration of CTAB and their CMC values further decrease in attendance of salts.A nonlinear behavior in the CMC versus T plot was observed in all the *** ΔG_m^0 values are found to be negative in present study systems demonstrated the stability of the *** values of ΔH_m^0 and ΔS_m^0 reveal the existence of hydrophobic and electrostatic interactions between CFH and *** thermodynamic properties of transfer for the micellization were also evaluated and discussed in *** dynamic simulation disclosed that environment of water and salts have impact on the hydrophobic interaction between CFH and *** water and salts,CTAB adopts spherical micelle in which charged hydrophilic groups are interacted with waters whereas hydrophobic tails form the core of the *** hydrophobic core region is highly conserved and *** addition,micelle formation is more favorable in aqueous Na Cl solution than other solutions.

关键词： Ciprofloxacin hydrochloride Cetyltrimethylammonium bromide Molecular dynamics Flydrophobic interaction Salt effect

Low Altitude Satellite Constellation for Futuristic Aerial-Ground Communications

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Computer Modeling in Engineering & Sciences 2023年第8期136卷 1053-1089页

作者： Saifur Rahman Sabuj Mohammad Saadman alam Majumder Haider md Akbar Hossain Al-Sakib Khan Pathan Department of Electronic Engineering Hanbat National UniversityDaejeon34158South Korea Department of Electrical and Electronic Engineering Brac UniversityDhaka1212Bangladesh School of Business and Digital Technologies Manukau Institute of TechnologyManukau2241New Zealand Department of Computer Science and Engineering United International UniversityDhaka1212Bangladesh

This paper discusses the significance and prospects of low altitude small satellite aerial vehicles to ensure smooth aerial-ground communications for next-generation broadband *** achieve the generic goals of fifthgeneration and beyondwireless networks,the existing aerial network architecture needs to be *** detailed architecture of low altitude aerial networks and the challenges in resource management have been illustrated in this ***,we have studied the coordination between promising communication technologies and low altitude aerial networks to provide robust network *** talk about the techniques that can ensure userfriendly control and monitoring of the low altitude aerial networks to bring forth wireless broadband connectivity to a new *** the end,we highlight the future research directions of aerial-ground communications in terms of access technologies,machine learning,compressed sensing,and quantum communications.

关键词： Aerial-terrestrial network cognitive radio network cooperative communication high altitude platform low altitude platform low earth orbit satellite constellation unmanned aerial vehicle

Assessing the pomfret stock for setting catch limits in the northern Bay of Bengal,Bangladesh

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Aquaculture and Fisheries 2024年第2期9卷 324-335页

作者： Mohammed Shahidul alam Qun Liu md Mostafa Monwar md Enamul Hoque Suman Barua md Leion Hassan Abdullah Munzer College of Fisheries Ocean University of ChinaQingdao266003China Department of Fisheries University of ChittagongChattogram4331Bangladesh Institute of Marine Sciences University of ChittagongChattogram4331Bangladesh Department of Oceanography University of ChittagongChattogram4331Bangladesh Department of Fisheries Ministry of Fisheries and LivestockDhaka1215Bangladesh

Pampus argenteus and Pampus chinensis form the high-value demersal Pomfret fishery of ***,due to a monotonic decline in catches over the last five years,it is essential to explore the current stock status concerning the removal rate to ensure the sustainability of this ***,given the reliability and minimal data requirements,this study employed an extended Bayesian State-Space Surplus Production Model,JABBA(Just Another Bayesian Biomass Assessment),to assess the stock *** results revealed that the stock biomass of the Pomfret fishery in the final year of the time series is significantly lower than BMSY,the biomass required to produce ***,this study recommends a yearly catch limit(TAC)of 10,000 metric tons to prevent further depletion of the stock ***,to avoid growth overfishing by allowing all immature fishes to reproduce at least once before being caught,this study also calculated the optimum length(Lopt)for catch for both species at which biologically maximum yield and revenue can be *** estimated Lopt is 25 cm for *** and 30 cm for ***,and not to capture fishes with lengths lower than these limits,this study further calculated the minimum mesh size limits for gill and set bag nets is 7.5 *** the mesh size regulation was estimated using length-based reference points derived from an empirical equation,this regulation can be used as an associate reference point when TAC is applied to assure the sustainability of this fishery.

关键词： Pomfret fishery Stock assessment JABBA TAC Lower length limits for catches Mesh size regulation

Analysis of the Impact of Optimal Solutions to the Transportation Problems for Variations in Cost Using Two Reliable Approaches

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American Journal of Computational Mathematics 2023年第4期13卷 607-618页

作者： Abdur Rashid md. amirul Islam Department of Mathematics Jahangirnagar University Dhaka Bangladesh Department of Mathematics Uttara University Dhaka Bangladesh

In this paper, we have used two reliable approaches (theorems) to find the optimal solutions to transportation problems, using variations in costs. In real-life scenarios, transportation costs can fluctuate due to different factors. Finding optimal solutions to the transportation problem in the context of variations in cost is vital for ensuring cost efficiency, resource allocation, customer satisfaction, competitive advantage, environmental responsibility, risk mitigation, and operational fortitude in practical situations. This paper opens up new directions for the solution of transportation problems by introducing two key theorems. By using these theorems, we can develop an algorithm for identifying the optimal solution attributes and permitting accurate quantification of changes in overall transportation costs through the addition or subtraction of constants to specific rows or columns, as well as multiplication by constants inside the cost matrix. It is anticipated that the two reliable techniques presented in this study will provide theoretical insights and practical solutions to enhance the efficiency and cost-effectiveness of transportation systems. Finally, numerical illustrations are presented to verify the proposed approaches.

关键词： Transportation Problem Initial Basic Feasible Solution Optimal Solution Two Reliable Approaches (theorems) and Numerical Illustrations

Geochemical characteristics of Holocene sediments from Chuadanga district, Bangladesh: Implications for weathering, climate, redox conditions, provenance and tectonic setting

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Chinese Journal Of Geochemistry 2014年第4期33卷 336-350页

作者： Ismail Hossain Krisna Kanta Roy Pradip Kumar Biswas Mahbubul alam md. Moniruzzaman Farah Deeba Department of Geology and Mining University of Rajshahi Bangladesh Institute of Mining Mineralogy and Metallurgy (IMMM) Joypurhat Bangladesh Water Resource Planning Division Institute of Water Modelling (IWM) Dhaka Bangladesh Institute of Nuclear Science and Technology (INST) Atomic Energy Commission Dhaka Bangladesh

The present research deals with the geochemical characteristics of the Holocene sediments from alamdanga area, Chuadanga district, Bangladesh. Main goals of the study are to delineate source rock characteristics, degree of chemical weathering and sorting processes and behavior of redox conditions during deposition of the sediments. Geochemical characteristics of the sediments show comparatively a wide variation in accordance with stratigraphy in their major element contents(e.g. Si O2 69.46–82.13, Al2O3 2.28–8.88 in wt%), reflecting the distinctive provenance and in part an unstable period in terms of tectonic activity. Geochemical classification of the sediments shows mostly sub-arkose with few sub-litharenites. Some major and trace elements display comprehensible correlation with Al2O3 confirming their possible hydraulic fractionation. The chemical index of alteration(CIA*), W* index, index of compositional variability(ICV), plagioclase index of alteration(PIA*) values and the ratio of Si O2/Al2O3, suggest low degrees of chemical weathering in the source areas as well as immature to moderately mature the sediments. The sediments suggest semi-arid climatic trends within oxic deltaic depositional conditions during the Holocene, at 3–12 ka. Whole rock geochemistry and discrimination diagrams demonstrate the continental signature derivatives, which might have been derived from the felsic to intermediate igneous rocks(granitic plutonic rocks) as well as from quartzose sedimentary/metamorphic provenance. These typical sources are present in a vast region of the Himalayan belt and catchment areas of Ganges. The tectonic setting of the sediments demarcates typically passive margin with slightly continental arc system.

关键词：地球化学特征氧化还原条件化学风化沉积物构造背景孟加拉国气候趋势全新世