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Efficient removal of heavy metals from electroplating wastewater using polymer ligands

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Frontiers of Environmental Science & Engineering 2016年第2期10卷 352-361页

作者： md. Lutfor RAHmAN Shaheen m. SARKAR mashitah mohd YUSOFF Faculty of Industrial Sciences & Technology Universiti Malaysia Pahang 26300 Gambang Kuantan Malaysia

Poly（hydroxamic acid）-poly（amidoxime） che- lating ligands were synthesized from poly（methyl acrylate-co-acrylonitrile） grafted acacia cellulose for removing toxic metal ions from industrial wastewaters. These ligands showed higher adsorption capacity to copper （2.80 mmol. g-l） at pH 6. In addition, sorption capacities to other metal ions such as iron, zinc, chromium, and nickel were also found high at pH 6. The metal ions sorption rate （tl/2） was very fast. The rate of adsorption of copper, iron, zinc, chromium, nickel, cobalt, cadmium and lead were 4, 5, 7, 5, 5, 8, 9 and 11 min, respectively. Therefore, these ligands have an advantage to the metal ions removal using the column technique. We have successfully investigated the known concentration of metal ions using various parameters, which is essential for designing a fixed bed column with ligands. The wastewater from electroplating plants used in this study, having chromium, zinc, nickel, copper and iron, etc. For chromium wastewater, ICP analysis showed that the Cr removal was 99.8% and other metal ions such as Cu, Ni, Fe, Zn, Cd, Pb, Co and mn removal were 94.7%, 99.2%, 99.9%, 99.9%, 99.5%, 99.9%, 95.6% and 97.6%, respectively. In case of cyanide wastewater, the metal removal, especially Ni and Zn removal were 96.5 and 95.2% at higher initial concentra- tion. For acid/alkali wastewater, metal ions removing for Cd, Cr and Fe were 99.2%, 99.5% and 99.9%, respectively. Overall, these ligands are useful for metal removal by column method from industrial wastewater especially plating wastewater.

关键词： heavy metals adsorption wastewater chelat-ing ligands plating industry

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 ecological risk for heavy metals in surface sediment of an urban river in a developing country

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International Journal of Sediment Research 2023年第6期38卷 834-846页

作者： md Saiful Islam md Humayun Kabir mir mohammad Ali md Towhidul Islam Asfia Niger md Humayun Kabir Zulhilmi Ismail Sujat Ahmed Khalid A.Ibrahim Abubakr m.Idris Department of Soil Science Patuakhali Science and Technology University Department of Environmental Science and Resource management Mawlana Bhashani Science and Technology University Department of Aquaculture Sher-e-Bangla Agricultural University Department of Soil Science Bangabandhu Sheikh Mujibur Rahman Agricultural University Centre for River and Coastal Engineering(CRCE) Universiti Teknologi Malaysia(UTM) Department of Water & Environmental Engineering Faculty of Civil EngineeringUniversiti Teknologi Malaysia(UTM) Environment Center for People & Environ(CPE) Department of Biology College of ScienceKing Khalid University Center for Environment and Tourism Studies and Research King Khalid University Department of Chemistry College of ScienceKing Khalid University Research Center for Advanced materials Science(RCAmS) King Khalid University

The speed of increasing threats to the riverine water resources makes it more critical to protect the health of Old Brahmaputra River *** current study was done to investigate the concentrations,distributions,sources,and ecological risk of heavy metals in surface sediment from the Old Brahmaputra River,*** were collected from seven sites and analyzed with an inductively coupled plasma-mass spectrometer(ICP-mS).The results showed that mean concentrations(mg/kg) of heavy metals were in the order of nickel(Ni)(44.69)> chromium(Cr)(30.16)> lead(Pb)(19.31)>copper(Cu)(17.84)> cadmium(Cd)(3.94)> arsenic(As)(2.73).The contamination factor(CF),pollution load index(PLI),enrichment factor(EF),and geo-accumulation index(Igeo) indicated low to moderate *** unit analysis revealed that the studied metals from all stations posed low *** sediment of the study river was uncontaminated to moderately contaminated,posing a minimal ecological ***,Cr,Ni,and Pb originated from anthropogenic sources rather than geogenic sources,and caused the severity of *** this regard,pollutant-based intensive monitoring of heavy metals and holistic ecological risk assessments are required to maintain a sound and healthy aquatic environment in the river.

关键词： Heavy metals Sediment quality Ecological risk Old Brahmaputra river Source identification

Active Force with Fuzzy Logic Control of a Two-Link Arm Driven by Pneumatic Artificial muscles

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Journal of Bionic Engineering 2011年第4期8卷 474-484页

作者： H. Jahanabadi m. mailah m. Z. md Zain H. m. Hooi Department of System Dynamics and Control Faculty of Mechanical Engineering Universiti Teknologi Malaysia 81310 UTM Johor Bahru Skudai Johor Malaysia

In this paper, the practicality and feasibility of Active Force Control （AFC） integrated with Fuzzy Logic（AFCAFL） applied to a two link planar arm actuated by a pair of Pneumatic Artificial muscle （PAm） is investigated. The study emphasizes on the application and control of PAm actuators which may be considered as the new generation of actuators comprising fluidic muscle that has high-tension force, high power to weight ratio and high strength in spite of its drawbacks in the form of high nonlinearity behaviour, high hysteresis and time varying parameters. Fuzzy Logic （FL） is used as a technique to estimate the best value of the inertia matrix of robot arm essential for the AFC mechanism that is complemented with a conventional Propor- tional-Integral-Derivative （PID） control at the outermost loop. A simulation study was first performed followed by an experi- mental investigation for validation. The experimental study was based on the independent joint tracking control and coordinated motion control of the arm in Cartesian or task space. In the former, the PAm actuated arm is commanded to track the prescribed trajectories due to harmonic excitations at the joints for a given frequency, whereas for the latter, two sets of trajectories with different loadings were considered. A practical rig utilizing a Hardware-In-The-Loop Simulation （HILS） configuration was developed and a number of experiments were carried out. The results of the experiment and the simulation works were in good agreement, which verified the effectiveness and robustness of the proposed AFCAFL scheme actuated by PAm.

关键词： pneumatic artificial muscle active force control fuzzy estimator hardware-in-the-loop simulation

Quasi-inverse Pendulum model of 12 DoF Bipedal Walking

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International Journal of Automation and computing 2017年第2期14卷 179-190页

作者： m. Akhtaruzzaman Amir A. Shafie md. Raisuddin Khan Department of mechatronics Engineering Kulliyyah of Engineering International Islamic University Malaysia Kuala Lumpur 53100 Malaysia

This paper presents modeling of a 12-degree of freedom （DoF） bipedal robot, focusing on the lower limbs of the system, and trajectory design for walking on straight path. Gait trajectories are designed by modeling of center of mass （Com） trajectory and swing foot ankle trajectory based on stance foot ankle. The dynamic equations of motion of the bipedal robot are derived by considering the system as a quasi inverted pendulmn （QIP） model. The direction and acceleration of Com movement of the QIP model is determined by the position of Com relative to the centre of pressure （COP）. To determine heel-contact and toe-off, two custom designed switches are attached with heel and toe positions of each foot. Four force sensitive resistor （FSR） sensors are also placed at the plantar surface to measure pressure that is induced on each foot while walking which leads to the calculation of CoP trajectory. The paper also describes forward kinematic （FIK） and inverse kinematic （IK） investigations of the biped model where Denavit-Hartenberg （D-H） representation and Geometric-Trigonometric （G-T） formulation approach are applied. Experiments are carried out to ensure the reliability of the proposed model where the links of the bipedal system follow the best possible trajectories while walking on straight path.

关键词： Humanoid robot quasi-inverse pendulum gait trajectory planning Anthropoid.

A study of groundwater irrigation water quality in south-central Bangladesh: a geo-statistical model approach using GIS and multivariate statistics

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Acta Geochimica 2018年第2期37卷 193-214页

作者： m.Atikul Islam md.mostafizur Rahman md.Bodrud-Doza md.Iftakharul muhib mashura Shammi Anwar Zahid Yeasmin Akter masaaki Kurasaki Department of Chemistry Hajee Mohammad Danesh Science and Technology University Department of Environmental Sciences Jahangirnagar University Graduate School of Environmental Science Hokkaido University Department of Environmental Pollution and Process Control Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Groundwater Hydrology Bangladesh Water Development Board Department of Chemistry University of Chittagong

Southern Bangladesh＇s irrigation and drinking water is threatened by saline intrusion. This study aimed to establish an irrigation water quality index （IWQI） using a geostatistical model and multivariate indices in Gopalganj district, south-central Bangladesh. Groundwater samples were taken randomly （different depths） in two seasons （wet-monsoon and dry-monsoon）. Hydrochemical analysis revealed groundwater in this area was neutral to slightly alkaline and dominating cations were Na^＋, mg^2＋, and Ca^2＋ along with major anions Cl^- and HCO3^-. Principal component analysis and Gibbs plot helped explain possible geochemical processes in the aquifer. The irrigation water evaluation indices showed： electrical conductivity （EC）〉750 μS/cm, moderate to extreme saline; sodium adsorption ratio （SAR）, excellent to doubtful; total hardness （TH）, moderate to very hard; residual sodium bicarbonate, safe to marginal; Kelly＇s ratio 〉1; soluble sodium percentage （SSP）, fair to poor; magnesium adsorption ratio, harmful for soil; and IWQI, moderate to suitable. In addition, the best fitted semivariogram for IWQI, EC, SAR, SSP, and TH confirmed that most parameters had strong spatial dependence and others had moderate to weak spatial dependence. This variation might be due to the different origin/sources of major contributing ions along with the influence of variable river flow and small anthropogenic contributions. Furthermore, the spatial distribution maps for IWQI, EC, SSP, and TH during both seasons confirmed the influence of salinity from the sea; low-flow in the major river system was the driving factor of overall groundwater quality in the study area. These findings may contribute to management of irrigation and/or drinking water in regions with similar groundwater problems.

关键词： Semivariogram Ordinary kriging model Salinity Irrigation water quality index GIS Hydrochemistry

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

Enhancement of the Sensitivity of Gas Sensor Based on microstructure Optical Fiber

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Photonic Sensors 2015年第4期5卷 312-320页

作者： monir mORSHED md. Imran HASAN S. m. Abdur RAZZAK Department of lnformation and Communication Technology Mawlana Bhashani Science and Technology University Tangail-1902 Bangladesh Department of Electronics & Telecommunication Engineering Rajshahi University of Engineering & Technology Rajshahi-6204 Bangladesh Department of Electrical & Electronic Engineering Rajshahi University of Engineering & Technology Rajshahi-6204 Bangladesh

This paper proposes the design and characterization of microstructure optical fiber for gas sensing applications. The aim is to detect toxic and colorless gases over a wide transmission band covering 0.80 gm to 2.00gm wavelength. Numerical investigation is carried out by using the finite element method （FEm）. The numerical study shows that sensitivity of the proposed sensor is moderately increased by introducing four non-circular holes around the defected core of photonic crystal fiber and the confinement loss is also reduced. Furthermore, we confirm that increasing the diameter of central air core and size of the non-circular holes can improve the relative sensitivity and the confinement loss is reduced by increasing the diameter of air holes in the cladding. The enhancement of the relative sensitivity is more than 27.58% （0.1323 to 0.1688） at the wavelength 2=1.33gm that is the absorption line of methane （CH4） and hydrogen fluoride （HF） gases. The confinement loss of the fiber is 1.765x 10-8dB/m.

关键词： Confinement loss gas sensor hollow core photonic crystal fiber microstrucmre fiber relativesensitivity

Spatial and seasonal distribution of intertidal macrobenthos with their biomass and functional feeding guilds in the Naf River estuary, Bangladesh

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Journal of Oceanology and Limnology 2019年第3期37卷 1010-1023页

作者： md. Abu NOmAN mAmUNUR Rashid m SHAHANUL Islam m. Belal HOSSAIN College of marine & Environmental Science Tianjin University of Science and TechnologyTianjin 300072China Department of Fisheries and marine Science Noakhali Science and Technology UniversityBangladesh Faculty of Food Engineering and Biotechnology Tianjin University of Science and TechnologyTianjin 300457China

The Naf River estuary is one of the most productive ecological ecosystems in Bangladesh providing an important feeding area for fishes and other aquatic ***,detailed information on macrobenthic communities is rarely available in this *** study focused on the seasonal and spatial variability of macrobenthic community structure with their biomass and functional *** total,fortyseven taxa were identified under nine major groups and seven functional feeding *** macrobenthic taxa,Polychaeta was dominant in both seasons and all over the estuary contributing 60%of total *** mean abundance of macrobenthos was higher during the pre-monsoon(2 972±1 994 inds./m^2)than the monsoon(1 572±361 inds./m^2)being maximum at mid-estuary region and minimum at upper and lower estuary *** the diversity indices,density(P=0.01,P=0.003),the number of taxa(P=0.000 3,P=0.000 9)and margalef′s Index(P=0.000 4,P=0.001)of macrobenthos were significantly different among stations and ***-Weiner index(P=0.009,P=0.12)and Pielou’s evenness index(P=0.03,P=0.14)had significant differences among stations but not among *** analysis suggested that distribution of macrofauna is strongly influenced by *** the feeding types,carnivorous were found to be dominant at the upper and mid-estuarine regions,and herbivorous were at lower estuarine *** species were dominant in both *** have shown to be the most abundant feeding type in terms of biomass though herbivores were highest during monsoon.

关键词： macrobenthos seasonal variation spatial variation feeding guilds biomass Naf River estuary