检索结果-南通市图书馆

Braking Performance of a Biomimetic Squid-Like Underwater Robot

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 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

Nutrient dynamics associated with leaf litter decomposition of three agroforestry tree species (Azadirachta indica, Dalbergia sissoo, and Melia azedarach) of Bangladesh

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 Forestry Research 2011年第4期22卷 577-582页

作者： Mahmood Hossain Mohammad Raqibul Hasan Siddique md. Saidur rahman md. Zaber Hossain md. Mahedi Hasan Forestry and Wood Technology Discipline Khulna University Khulna - 9208 Bangladesh Soil Science Discipline Khulna University Khulna-9208 Forestry and Wood Technology Discipline Khulna University Khulna- 9208

Azadirachta indica A. Juss, Dalbergia, sissoo Roxb., and Melia azedarach L. are little studied species in nutrient return capabilities from leaf litter decomposition to maintenance of the soil fertility despite their importance in agroforestry practices of Bangladesh. A leaf litter decomposition experiment was conducted using a litterbag teeh7 nique to assess the nutrient reaun efficiency of these species. The de- composition rate of leaf litter was highest for M. azedarach and lowest for D. sissoo. Rainfall and temperature of study sites showed a significant （p〈0.05） positive relationship with the rate of leaf litter decomposition. The highest decay constant was observed for M. azedarach （6.67）. Nitrogen and Phosphorus concentration in leaf litter showed a decreased trend sharply at the end of the first month, whereas rapid decrease of Potassium concentration was reported within 10 days. Conversely, higher concentration of nutrient was observed at the later stages of decomposition. All three species showed a similar pattern of nutrient release （K 〉 N 〉 P） during the decomposition process of leaf litter. Among the studied species, D. sissoo was best in terms of N and P return and A. indica was best in terms of K return.

关键词： agroforestry decay constant decomposition leaf litter andnutrient dynamics

Can picnic influence floral diversity and vitality of trees in Bhawal National Park of Bangladesh?

在线全文

学校读者我要写书评

暂无评论

Forestry Studies in China 2009年第3期11卷 148-157页

作者： md. Mizanur rahman Harald VACIK Institute of Silviculture Department of Forest and Soil Sciences University of Natural Resources and Applied Life Sciences Vienna A-1190 Austria

We examined the impact of picnic activities on forest diversity, structure, regeneration and vitality of tree species in the Bhawal National Park of Bangladesh. The study area was classified as a non-used, occasionally used and frequently used area on the basis of the intensity of the picnic activities. A total of 43 plant species were enumerated in the whole study area. The highest plant species richness （41 species） was observed in the non-used area whereas the lowest species richness （11 species） in the frequently used area. The diversity index decreased with the increase of picnic intensity whereas the concentration of dominance increased. Density of all plant groups except mature trees, and the basal area of the mature trees showed a declining trend from the non-used to frequently used area. The frequently used area exhibited very poor regeneration. Tree vitality decreased with the increase of picnic intensity. The relevance of our study as a basis for further research to determine the impact of tourism on biodiversity in Bangladesh is discussed.

关键词： species richness diversity index concentration of dominance regeneration intensity

Capturing transition and non-transition flows with a new shear stress transport model

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第3期36卷 121-136页

作者： md.Mizanur rahman School of Mechanical Engineering Hangzhou Dianzi UniversityHangzhou 310018China

A new Shear Stress Transport(SST)k-ω model is devised to integrate salient features of both the non-transitional SST k-ω model and correlation-based γ-Re_(θ) transition *** exceptionally simplified approach is applied to extend the New SST(NSST)model capabilities toward transition/non-transition ***’s stress-intensity factor R_(b)=|-uv|/k can be parameterized with the wall-distance dependent Reynolds number Re_(y)=√ky/v;however,as the Re_(y)is replaced by a“flow-structure-adaptive”parameter R_(μ)=v_(T)/v,the resulting R_(b)is capable of capturing various transition phenomena *** prospective stress-intensity parameter R_(b)=R_(b)(Re_(y),R_(μ))is incorporated in the constitutive relations for eddy-viscosity v_(T) and production term P_(k).The proposed formulation is intrinsically plausible,having a dramatic impact on the prediction of bypass,separation-induced and natural transitions together with non-transitional *** extra viscous-production term P_(k)^(lim) is added with the k-equation to ensure proper generation of k at the viscous sublayer when computing separation-induced transition over a Low-Reynolds Number(LRN)*** demonstrate that the NSST k-ω model maintains an excellent consistency with both SST k-ω and γ-Re_(θ) models.

关键词： γ-Re_(θ)model Non-transition Stress-intensity parameter SST model Transition

Impact of non-alcoholic fatty liver disease on coronavirus disease 2019: A systematic review

在线全文

学校读者我要写书评

暂无评论

World Journal of Hepatology 2024年第8期16卷 1185-1198页

作者： Abdul Moeed Muhammad Omar Larik Muhammad Ahmed Ali Fahim Hafsah Alim Ur rahman Lubna Najmi Mah I Kan Changez Muhammad Moiz Javed md.Al Hasibuzzaman Department of Internal Medicine Dow University of Health SciencesKarachi 74200SindhPakistan Department of Internal Medicine Dow International Medical CollegeKarachi 74200SindhPakistan Department of Internal Medicine Ziauddin UniversityKarachi 75000SindhPakistan Department of Research Yale UniversityNew Haven 06520CTUnited States Department of Internal Medicine King Edward Medical UniversityLahore 54000PunjabPakistan Institute of Nutrition and Food Science University of DhakaDhaka 1000Bangladesh Department of Medicine The Affiliated Hospital of Medical School of Ningbo UniversityNingbo 315211Zhejiang ProvinceChina

BACKGROUND Many studies have revealed a link between non-alcoholic fatty liver disease(NA-FLD)and coronavirus disease 2019(COVID-19),making understanding the relationship between these two conditions an absolute *** To provide a qualitative synthesis on the currently present data evaluating COVID-19 and *** This systematic review was conducted in accordance with the guidelines pro-vided by preferred reporting items for systematic reviews and meta-analyses and the questionnaire utilized the population,intervention,comparison,and outcome *** search strategy was run on three separate databases,PubMed/MEDLINE,Scopus,and Cochrane Central,which were systematically searched from inception until March 2024 to select all relevant *** addition,***,***,and Google Scholar were searched to identify grey *** After retrieval of 11 studies,a total of 39282 patients data were *** was found in 11.5%and 9.4%of people in NAFLD and non-NAFLD *** all,23.2%of NAFLD patients and 22%of non-NAFLD admissions diagnosed with COVID-19 were admitted to the intensive care unit,with days of stay *** support ranged from 5%to 40.5%in the NAFLD cohort and from 3.1%to 20%in the non-NAFLD *** incidence of acute liver injury showed *** improvement on days 7 and 14 between the two classifications was *** stay ranged from 9.6 days to 18.8 days and 7.3 days to 16.4 days in the aforementioned cohorts respectively,with 73.3%and 76.3%of patients being *** rates *** Clinical outcomes except mortality consistently showed a worsening trend in patients with NAFLD and concomitant *** research in conducting prospective longitudinal studies is essential for a more powerful conclusion.

关键词： Non-alcoholic fatty liver disease Coronavirus disease 2019 Mechanical ventilation Intensive care unit Acute liver injury

Assessment of natural regeneration status and diversity of tree species in the biodiversity conservation areas of Northeastern Bangladesh

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 Forestry Research 2011年第4期22卷 551-559页

作者： md. Habibur rahman md. Abu Sayed Arfin Khan Bishwajit Roy Most. Jannatul Fardusi Department of Forestry and Environmental Science School of Agricul- ture and Mineral Sciences Shahjalal University of Science and Tech- nology Sylhet-3114 Bangladesh Department of Disturbance Ecology University of Bayreuth Bayreuth Germany

A study was conducted at two-biodivcrsity conservation areas of Northeastern Bangladesh （a part of Sylhet Forest Division） to assess the species composition, diversity and density of natural regeneration of tree species both indigenous and exotic species. Data were collected by stratified random quadrate method during January 2010 to July 2010. Totally 200 circular plots of 2 m〉〈2 m in size had 5 different habitat types of plants namely; forest, roadside, homestead （surrounding forest dwellers house）, fallow land and others （canals, streams and tea gardens side）, which included a total of 55 regenerating species belonging to 28 families. Meliaceae is the dominant family and shows the highest family importance value （26.3）, having six species, followed by Moraeeae （24.24）. Among the five habitat types, forest （43 species） possess the highes number of species, followed by roadside （23 species）. Total 15 exotic species among 9 families and 40 indigenous species with 24 families were recorded. For exotic species, Tectona grandis possess the highest relative density （11.7%） and relative frequency （10.5%）; Senna siamea had highest relative abundance （7.83%）. In case of indigenous species, Chickrassia tabularis possess the highest relative density （4.23%） and relative frequency （4%）; Dipterocarpus turbinatus bad the highest relative abundance （3.92%）. Tectona grandis （29.66） and Chickrassia tabularis （10.8） had the highest IVI for exotic and indigenous species respectively. Different diversity indic＇es such as Shanon-Winner diversity index,＇ species diversity index, species richness index, species evenness index, Simpson index and species dominance index, etc. were applied to quantify definite diversity. The regeneration of species associated with low levelsof disturbance was in the exotic Species. Study suggests that proper protection from human disturbances and scientific management of natural regeneration of two-study forests may lead a rich biodiversity site in the cou

关键词： biodiversity exotic species family importance value indigenous species quantitative characters

Effect of different additives on the phase separation behavior and thermodynamics of p-tert-alkylphenoxy poly (oxyethylene) ether in absence and presence of drug

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第5期26卷 1110-1118页

作者： Marzia rahman md. Anamul Hoque Mohammed Abdullah Khan Malik Abdul Rub Abdullah M. Asiri Department of Chemistry Jahangirnagar University Savar Dhaka 1342 Bangladesh Chemistry Department Faculty of Science King Abdulaziz University Jeddah 21589 Saudi Arabia Center of Excellence for Advanced Materials Research King Abdulaziz UniversityJeddah 21589 Saudi Arabia

Cloud point （CP） determinations of 4-（1,1,3,3-tetramethylbutyl）phenyl-polyethylene glycol （TX-100 （nonionic surfactant）） was carried out in aqueous as well as in the attendance of drug （ceftriaxone sodium trihydrate （CFT））/（CFT ＋ different inorganic salts） and discussed thoroughly. Nonionic surfactants are employed exten- sively in different formulations. In aqueous solution, the values of CP of TX-100 are obtained to increase by means of enhancing of their concentration in the solution. The CP values of TX-100 solutions were found to de- crease in the presence of drug and their values decrease more with rising concentrations of the drug. The values of CP of CFT and TX-100 mixtures were found to further decrease in the attendance of inorganic salts in compar- ison to their absence. The effect of different sodium salts in decreasing CP values of TX-100 was achieved in the following order： NaCO3 〉 Na2SO4 〉 NaCl. However, in the case of potassium and ammonium salts, the decreasing order obtained is K2SO4 〉 KCO3 〉 KCI and （NH4）2SO4 〉 Na2CO3 〉 NH4Cl respectively. Various thermodynamic pa- rameters for example standard free energy （△G c）, standard enthalpy （△H c） as well as standard entropy （△S c） changes of phase separation were also evaluated and discussed in detail on the basis of their behavior.

关键词： Cloud point TX-100 Ceftriaxone sodium trihydrate Inorganic salts Thermodynamic parameters

Reproductive Isolating Mechanisms in the Bangladesh Coastal Bullfrog Hoplobatrachus litoralis and Its Congeneric Species Revealed by Crossing Experiments and Examination on Spermatogenesis of the Hybrids

在线全文

学校读者我要写书评

暂无评论

Asian Herpetological Research 2017年第1期18卷 27-38页

作者： Mahmudul HASAN Mohammed Mafizul ISLAM md. Mukhlesur rahman KHAN Ratanasate WANICHANON Atsushi KURABAYASHI Masayuki NUMIDA Amphibian Research Center Hiroshima University 1-3-1 Kagamiyama Higashihiroshima 739-8526 Japan Department of Fisheries Biology and Genetics Bangladesh Agricultural University Mymensingh-2202 Bangladesh Department of Anatomy Phramonkutklao Medical College Rajawithi Rd. Bangkok 10400 Thailand 1-6-15 Ushitaasahi Higashi ku Hiroshima 732-0067 Japan

To elucidate reproductive isolating mechanisms in the Bangladesh coastal bullfrog Hoplobatrachus litoralis and its congeneric species, we performed crossing experiments using three species： H. litoralis, H. tigerinus and H. rugulosus. In addition, we conducted histological observations on spermatogenesis of the hybrids. The reciprocal hybrids between H. litoralis and H. tigerinus developed normally with somewhat lower viability at the metamorphosis stage compared with the controls. Most of the metamorphosed frogs became mature. On the other hand, almost all hybrids between female H. rugulosus and male H. litoralis or H. tigerinus died of underdevelopment at the tadpole stage, and only a few hybrids metamorphosed normally and survived to maturity. The inner structures of the testes of the control H. litoralis and H. tigerinus were completely normal, with seminiferous tubules filled with compact bundles of normal spermatozoa. Those of the reciprocal hybrids between H. litoralis and H. tigerinus were almost normal or slightly abnormal, with seminiferous tubules that contained pycnotic nuclei in addition to normal bundles of normal spermatozoa, which demonstrates slight abnormalities in spermatogenesis. In contrast, the hybrids between female H. rugulosus and male H. litoralis or H. tigerinus had no bundles of spermatozoa nor spermatids in the seminiferous tubules, which indicates entirely abnormal spermatogenesis. Meiotic chromosome figures in the reciprocal hybrids between H. litoralis and H. tigerinus showed slight abnormalities, with the occurrence of univalents and increase of rod-shaped bivalents. These results indicate that H. litoralis and H. tigerinus are not isolated from each other by hybrid inviability nor by hybrid sterility, although the hybrids showed somewhat abnormal spermatogenesis in hybrids and that H. rugulosus is isolated from both H. litoralis and H. tigerinus by incomplete hybrid inviability and complete hybrid sterility.

关键词： Hoplobatrachus reproductive isolation interspecific hybrids spermatogenesis meiotic chromosomes

Cardio- and hepato-protective potential of methanolic extract of Syzygium cumini(L.) Skeels seeds:A diabetic rat model study

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2017年第2期7卷 126-133页

作者： Sumaiya Nahid Kishor Mazumd.r Zillur rahman Saiful Islam md. Humayun Rashid Philip Grey Kerr Department of Pharmacy University of Science and Technology ChittagongFoy's LakePahartaliChittagong 4202Bangladesh School of Biomedical Sciences Charles Sturt UniversityBoorooma StreetWaggaWaggaNew South Wales 2678Australia Department of Pathology Chittagong Medical College HospitalChittagong 4202Bangladesh

Objective: To evaluate the effect of methanolic extract of Syzygium cumini(L.) Skeels(S. cumini) seeds on the major organs in an animal model of diabetes through biochemical and histopathological ***: The methanolic extracts of S. cumini seeds(100 and 200 mg/kg body weight) were administered to alloxan-induced diabetic rats daily, with fasting blood glucose levels being measured by glucometry at one-day interval for a duration of two weeks. Biochemical assays to evaluate changes in the functions of the heart, liver,pancreas and kidney were carried out. Histopathological changes in the diabetic rat organs(pancreas, liver, heart, kidney and spleen) were also observed after the 14 days of treatment with the ***: Oral administration of methanolic extracts of S. cumini seeds(100 and 200 mg/kg body weight), with gliclazide as a positive control(25 mg/kg), showed beneficial effects including lowering blood glucose levels(P < 0.001), improved heart and liver functions, and hyperlipidemia due to diabetes. At 200 mg/kg, the extracts reversed cardiac and liver damage caused by ***: In addition to the anti-hyperglycemic activity of methanolic extracts of S. cumini seeds, the extracts demonstrates potential to minimize cardiac and hepatic complications.

关键词： Syzygium cumini seeds Diabetes Cardioprotection Hepatoprotection