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Braking Performance of a Biomimetic Squid-Like Underwater Robot

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Journal of Bionic Engineering 2013年第3期10卷 265-273页

作者： md. Mahbubar rahman Sinpei Sugimori Hiroshi Miki Risa Yamamoto Yugo Sanada Yasuyuki Toda Laboratory of Hull Form Design Department of Naval Architecture and Ocean Engineering Graduate School of Engineering Osaka University Osaka 565-0871 Japan

In this study, the braking performance of the undulating fin propulsion system ofa biomimetic squid-like underwater robot was investigated through free run experiment and simulation of the quasi-steady mathematical model. The quasi-steady equa- tions of motion were solved using the measured and calculated hydrodynamic forces and compared with free-run test results. Various braking strategies were tested and discussed in terms of stopping ability and the forces acting on the stopping stage. The stopping performance of the undulating fin propulsion system turned out to be excellent considering the short stopping time and short stopping distance. This is because of the large negative thrust produced by progressive wave in opposite direction. It was confirmed that the undulating fin propulsion system can effectively perform braking even in complex underwater explorations.

关键词： biomimetics squid-like underwater robot undulating fin propulsion system braking performance motion simulation

Improvement on electrochemical performances of nanoporous titania as anode of lithium-ion batteries through annealing of pure titanium foils

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Journal of Energy Chemistry 2018年第1期27卷 250-263页

作者： md.Arafat rahman Yat Choy Wong Guangsheng Song De Ming Zhu Cuie Wen Faculty of Science Engineering and TechnologySwinburne University of Technology Department of Mechanical Engineering Chittagong University of Engineering and Technology School of Material Science&Engineering Anhui University of Technology School of Engineering RMIT University

The effect of annealing of Ti foils before anodization on the morphology and electrochemical performance of resultant nanoporous anatase TiO2 （np-TiO2） as anode in rechargeable lithium-ion batteries （LIBs） was investigated. The np-TiO2 anode fabricated from annealed Ti foils exhibited higher specific surface area and reduced pore diameter compared to np-TiO2 electrode fabricated from as-received Ti foils. The highly porous np-TiO2 anode fabricated from annealed Ti foils exhibited 1st discharge capacity of 453.25 mAh/g and reduced to 172.70 mAh/g at 1 C current rate after 300 cycles; whilst the np-TiO2 electrode fabricated from the as-received Ti foils exhibited 1st discharge capacity of 213.30 mAh/g and reduced to 160.0 mAh/g at 1 C current rate after 300cycles. Even after 400cycles, such np-TiO2 electrode exhibited a reversible capacity of 125.0 mAh/g at 2.5 C current rate. Compared to the untreated Ti foils, the enhanced electro- chemical performance of np-TiO2 anode fabricated from annealed Ti foils was ascribed to the annealing- induced removal of residual stress among the Ti atoms. The benefit of annealing process can reduce pore size of as-fabricated np-TiO2.

关键词： Annealing Nanoporous Anatase Titanium oxide Anode Lithium-ion battery

Soil resistivity and ground resistance for dry and wet soil

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Journal of Modern Power Systems and Clean Energy 2017年第2期5卷 290-297页

作者： md.Abdus SALAM Quazi Mehbubar rahman Swee Peng ANG Fushuan WEN Department of Electrical and Electronic Engineering Faculty of EngineeringUniversiti Teknologi BruneiJalan Tungku LinkBandar Seri BegawanBrunei-Muara BE1410Brunei Darussalam Department of Electrical and Computer Engineering The University of Western OntarioLondonOntario N6A 5B9Canada

In this paper, soil resistivity and ground resistance at two different sites near an electrical substation are measured using a grounding system grid with and without rods. With the Wenner four-pole equal-method, the soil resistivity is measured at both selected sites, one of which contains wet soil while the other contains dry soil. Cymgrd simulation software is then used to determine the acceptability of these measured resistivity values by finding out the root mean square error between the measured and calculated values for both wet and dry soil sites. These values for wet and dry soil sties were found to be only 0 %and 4.92 %, respectively, and deemed acceptable. The measured soil resistivity values were then used to evaluate the ground resistance values of a grounding grid ‘with rod’for the wet soil site and ‘without rods’ for the dry soil site,and then compared with the simulated ground resistance values. These comparisons were also found to be in good agreement. In addition, ground potential rise, maximum permissible step and touch potentials have also been estimated using the simulation software.

关键词： Grid with rods Grid without rods Fall-ofpotential method Soil resistivity Ground resistance

Contribution of non-timber forest products to the livelihoods of the forest-dependent communities around the Khadimnagar National Park in northeastern Bangladesh

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Regional Sustainability 2021年第3期2卷 280-295页

作者： md.Habibur rahman Bishwajit ROY md.Shahidul ISLAM Laboratory of Tropical Forest Resources and Environments Division of Forest and Biomaterials ScienceGraduate School of AgricultureKyoto UniversityKyoto606-8502Japan Bangladesh Institute of Social Research Trust LalmatiaDhaka1207Bangladesh Climate Change andSustainable Development Policies Faculty of ScienceUniversity of LisbonLisbon1749-016Portugal Research and Development Cell Bangladesh Knitwear Manufacturers and Exporters AssociationDhaka1000Bangladesh

Non-timber forest products(NTFPs)play a significant role in the improvement of the forest-dependent people’s livelihoodsaround the world,strengthening protection for the sustainable use of *** purpose of this research was to evaluate the influence of occupational category-wise(fuelwood collectors,farmers,small-scale businessmen,day labourers,and tea estate labourers)dependencyon NTFPsand the role of NTFPs on household income around the Khadimnagar National Park(KNP)in northeastern *** 2014,178purposively selected respondents from four villages(out of 22 villagesaround the KNP)were interviewed face-to-face using a semi-structured *** study observed that these forest-dependent communities utilized resources of the KNP mainly for domestic energy supply,household income,and house *** showed that income from NTFPs made a significant contribution to family *** data analysis indicated that small-scale businessmen earned relatively more income from NTFPs,followed by tea estate labourersand day *** study revealed significant negative relationships of the distance of households from the forest with the amount of NTFPs collected(P<0.01)and monthly income from NTFPs(P<0.01).Positive significant relationships were found between the amount of NTFPs collected and the time spent in NTFP collection(P<0.001),as well as betweenmonthly income from NTFPs and family size(P<0.001).The fuelwood collectors and farmers collected significantly greater amounts of NTFPs per trip(P<0.001)than other occupational *** households that were moderately to highly dependent on NTFPs collected significantly higher amounts of NTFPs pertrip(P<0.01)than the households that were moderately dependent and less dependent on *** dependence on KNP’sresources,community’sappreciation of the KNP’s ecosystem services for villagers’livelihoods,and community’s high levels of concern for forest conservation provided a foundation

关键词： Forest dependency Household income Non-timber forest products Forest sustainability Occupational categories Khadimnagar National Park

Effect of different pre-sowing treatments on seed germination percentage and growth performance of Acacia auriculiformis

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Journal of Forestry Research 2011年第2期22卷 183-188页

作者： md.Salim Azad Mizanur rahman Manik md.Shamin Hasan md.Abdul Matin Forestry and Wood Technology Discipline Khulna University

Seed morphology,germination and seedlings growth of Acacia auriculiformis were *** experiment was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,*** seeds of the species were collected from healthy trees of road side plantation from different areas of Khulna District,Bangladesh and treated with five pre-sowing treatments（control,immersion in cold water,immersion in hot water,scarification with sand paper and immersion in concentrated H2SO4）.The average length,breadth and thickness were found to be（0.58±0.017） cm,（0.44±0.007） cm and（0.20±0.089） cm,*** was conducted in polybags with a mixture of top soil,coconut husk,coarse sand,and fine sand in a ratio of 3：4：1：*** reveal that pre-sowing treatments influences the germination rates of seeds that significantly increase the percentage germination compared with those in control（43%） and cold water treatment（52%）.The highest germination success rate was found 83% in hot water treatment followed by 78% in scarification with sand paper,and 75% with immersion in *** started from 7 to 12 days and completed between 28 and 35 days period in all *** showed the significant difference（p0.05） among the treatments in seed germination,but no significant difference among treatment with regard to starting day,closing day and total germination *** case of height and diameter growth,seedlings originated from the seeds with hot water treatment shows significantly higher in wet season（from May to July）.Hot water treatment can be recommended on seed germination of the species in rural Bangladesh.

关键词： seed germination seed dormancy pre-sowing treatment seedling growth Acacia auriculiformis

Reproductive development of two groundnut cultivars as influenced by boron and light

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Information Processing in Agriculture 2018年第2期5卷 289-293页

作者： md.Quamruzzaman md.Jafar Ullah md.Fazlul Karim Nazrul Islam md.Jahedur rahman md.Dulal Sarkar Department of Agronomy Sher-e-Bangla Agriculture UniversityDhaka 1207Bangladesh Department of Horticulture Sher-e-Bangla Agriculture UniversityDhaka 1207Bangladesh

Boron is an important micronutrient that enhances reproductive growth of crops such as *** also plays an important role for pegging of *** has been little information on the application of boron and light in groundnut in Bangladesh.A field experiment was conducted to study the effects of boron and light on the reproductive development of two groundnut *** considered as two groundnut cultivars,viz.,‘Dhaka-1(C1)’and‘BARI Chinabadam-8(C2)’,three levels of boron(B),viz.,0-kg B ha^-1(B0),1-kg B ha^-1(B1)and 2-kg B ha^-1(B2),and two levels of light,viz.,normal day light(≈12-h light)and normal day light+6-h extended red light at night(≈18-h light).Result revealed that the reproductive development,yield and shelling percentage of groundnut were markedly increased with the application of *** to imposition of light all of reproductive units increased but decrease number of pods and pod *** highest reproductive unit and yield were observed from‘BARI Chinabadam-8’.Therefore,reproductive development could be improved by application of boron in improved cultivars(BARI Chinabadam-8)but not for under extended light.

关键词： Groundnut Reproductive development Light Boron Pegs Pods Shelling percentage

Distribution of heavy metals in water and sediment of an urban river in a developing country:A probabilistic risk assessment

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International Journal of Sediment Research 2022年第2期37卷 173-187页

作者： Mir Mohammad Ali Saima rahman md Saiful Islam md Refat Jahan Rakib Shaharior Hossen md Zillur rahman Tapos Kormoker Abubakr M. Idris Khamphe Phoungthong Institute of Disaster Management Khulna University of Engineering and Technology Department of Aquaculture Sher-e-Bangla Agricultural University Department of Urban and Regional Planning Khulna University of Engineering and Technology Department of Soil Science Patuakhali Science and Technology University Department of Fisheries and Marine Science Noakhali Science and Technology University Department of Fisheries Science Chonnam National University Quality Control Chemistry Lab Department of Fisheries Department of Emergency Management Patuakhali Science and Technology University Department of Chemistry College of Science King Khalid University Research Center for Advanced Materials Science (RCAMS) King Khalid University Environmental Assessment and Technology for Hazardous Waste Management Research Center Faculty of Environmental Management Prince of Songkla University

River water and sediment embody environmental characteristics that give valuable eco-environmental *** to rapid industrialization,the aquatic environment of any urban river can be seriously polluted by heavy metals(HMs).The global concern is caused by heavy metal pollution because of its potential harm to aquatic ecosystems and human *** the Bhairab River,Bangladesh,surface sediment concentrations of globally alarming toxic metals such as arsenic(As),chromium(Cr),cadmium(Cd),and lead(Pb) were measured to determine the ecological and human health risks of the riverine *** average As,Cr,Cd,and Pb concentrations in water were 3.55,31.74,1.44,and23.82 μg/L,respectively,and in sediment were 4.13,34.17,1.66,and 25.46 mg/kg,*** the winter,metals in sediment were higher than during the *** most sediment samples,the enrichment factor(EF),contamination factor(CF),geoaccumulation index(I),pollution load index(PLI) of As,Cr,Cd,and Pb indicated moderate *** potential ecological risk(PER) in sediment followed the descending order of Cd> As> Pb> *** contamination level of toxic metals implied that the condition is frightening and probably severely affecting the aquatic ecology of this riverine ecosystem.

关键词： Toxic metals Environmental risk Bioaccumulation Ecological risk Bangladesh

Geochemistry of subsurface Late Quaternary ironstones in Rajshahi and Bogra Districts, Bangladesh: implications for genetic and depositional conditions

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Acta Geochimica 2019年第3期38卷 404-413页

作者： md.Sazzadur rahman Ismail Hossain Pradip Kumar Biswas md.Abdur Rahim A.S.M.Mehedi Hasan md.Ibrahim Adham Department of Geology and Mining University of Rajshahi Institutes of Mining Mineralogy and Metallurgy (IMMM)BCSIR Department of Disaster Resilience and Engineering Patuakhali Science and Technology University

The present study deals with the geochemistry of Late Quaternary ironstones in the subsurface in Rajshahi and Bogra districts, Bangladesh with the lithological study of the boreholes sediments. Major lithofacies of the studied boreholes are clay, silty clay, sandy clay, fine to coarse grained sand, gravels and sands with(fragmentary) ironstones. The ironstones contain major oxides, Fe_2 O_3*(*total Fe)(avg. 66.6 wt%), SiO_2(avg. 15.3 wt%), Al_2 O_3(avg. 4.0 wt%), MnO(avg. 7.7 wt%), and CaO(avg. 3.4 wt%). These geochemical data imply that the higher percentage of Fe_2 O_3* along with Al_2 O_3 and MnO indicate the ironstone as goethite and siderite, which is also validated by XRD data. A comparatively higher percentage of SiO_2 indicates the presence of relative amounts of clastic quartz and manganese-rich silicate or clay in these rocks. These ironstones also have significant amounts of MnO(avg. 7.7 wt%) suggesting their depositional environments under oxygenated condition. Chemical data of these ironstones suggest that the source rock suffered deep chemical weathering and iron was mostly carried in association with the clay fraction and organic matter. Iron concretion was mostly formed by bacterial build up in swamps and marshes, and was subsequently embedded in clayey *** the coastal environments, the water table fluctuates and goethite and siderite with mud and quartz became dry and compacted to form ironstone.

关键词： Ironstone Geochemistry Goethite Siderite Bangladesh

Assessment of heavy metal contamination in the sur?cial sediments from the lower Meghna River estuary, Noakhali coast, Bangladesh

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International Journal of Sediment Research 2021年第3期36卷 384-391页

作者： Mohammad Abdul Momin Siddique Mahfuzur rahman Shahriar md.Arifur rahman md.Rubel Hassan Zeenath Fardous Muhammed Alamgir Zaman Chowdhury Mohammad Belal Hossain Department of Oceanography Noakhali Science and Technology University Agrochemical and Environmental Research Division Institute of Food and Radiation Biology Atomic Energy Research Establishment 5. Department of Fisheries and Marine Science Noakhali Science and Technology University Department of Environmental Science and Disaster Management Noakhali Science and Technology University University of South Bohemia in Ceske Budejovice Faculty of Fisheries and Protection of Waters South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses Research Institute of Fish Culture and Hydrobiology

Sediment samples were collected from ten selected sites of the lower Meghna River estuary, and six heavy metals were analyzed with Atomic Absorption Spectrophotometry(AAS) to assess the contamination level and the metals’ association with sediment grain size. The current results revealed that the mean concentrations of the studied metals were ranked in descending order of iron(Fe)(1.29 ? 103 mg/kg) > zinc(Zn)(42.41 mg/kg) > lead(Pb)(12.48 mg/kg) > chromium(Cr)(10.59 mg/kg) > copper(Cu)(6.22 mg/kg) > cadmium(Cd)(0.28 mg/kg). The geo-accumulation, contamination, and pollution load indexes suggested that the lower Meghna river estuary was not contaminated by Fe, Zn, Pb, Cr, and *** mean size of the sediment ranged from 28.92 to 126.2 mm, and the Pearson correlation coefficient showed a significant association between Fe and Pb(coefficient of determination, r2? 0.836; p < 0.05),and no significant correlation was found between individual metals and grain size, indicating no or low influence on the metals distribution.

关键词： Metal pollution Pollution load index Grain size Trace metals