Pollutant Dispersion Characteristics in Dhaka City, Bangladesh

Khandaker M. A. Hossain,Said M. Easa 한국기상학회 2012 Asia-Pacific Journal of Atmospheric Sciences Vol.48 No.1

Air pollution is a major environmental concern in major cities around the world. The major causes of air pollution include rapid industrialization/urbanization and increased non environmentfriendly energy production. This paper analyses the atmospheric pollutant such as carbon monoxide (CO) and particulate matter (PM)dispersion characteristics of Dhaka city. The yearly and diurnal variations of pollutant concentration are described by taking into consideration of both meteorological and emission source parameters highlighting washout effect due to rainfall and inversion phenomena. Concentration of PM (both PM2.5 and PM10) and CO in the ambient air are measured for a period of one year with Airmetric Minivol air samplers and Gas Chromatographic (GC) technique, respectively. The trend over the year shows an increase in the monthly average hourly PM and CO concentrations in winter months (November to March)when both PM10 and PM2.5 annual average concentrations (about 130 and 95 μgm−3, respectively) exhibit levels exceeding World Health Organization (WHO) guidelines as well as exceed more than twice the national standards of annual PM10 (50 μg m−3) and PM2.5 (15μg m−3) concentrations. Such high pollutant concentrations may have significant health implications for residents of Dhaka city. It is also found that the PM concentration increases with the increase of wind speed during dry winter season and is also influenced by transboundary air pollution. The data and subsequent recommendations can be useful in formulating air quality management strategies for the Dhaka city.

Measurements of the Proton-Induced Reaction Cross-Sections of natMo by Using the MC50 Cyclotron at the Korea Institute of Radiological and Medical Sciences

Mayeen Uddin KHANDAKER,Guinyun Kim,A.K.M. Moinul Haque Meaze,Dongchul Son,Kwangsoo Kim,Young Seok Lee 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.4

We measured the production cross-sections of 99mTc, 96(m+g)Tc, 95mTc, and 95gTc radioisotopes for proton-induced reactions on molybdenum by using a stacked-foil activation technique in the energy range of 10 . 30 MeV at the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences. Reactions induced on the aluminum and copper foils were used to monitor the parameters of the proton beam. The present measurements are in generally good agreement with the earlier reported data in the investigated energy region. reg_id_no

The presence of carcinogenic radon in the Padma River water, adjacent to the Rooppur Nuclear Power Plant

Siraz M.M. Mahfuz,Alam M.S.,Jubair A.M.,Das S.C.,Ferdous J.,Hossain Z.,Das S.,Khandaker Mayeen Uddin,Bradley D.A.,Tokonami Shinji,Yeasmin S. 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.8

Radon is a naturally occurring carcinogenic agent, poses a serious health hazard when inhaled or ingested in significant amounts. The water of the Padma river will be used as a tertiary coolant for the soon-to-be-commissioned ‘Rooppur Nuclear Power Plant’. Hence, it is important to assess the radiological status of the river prior to the commission of this power plant. Therefore, for the first time, 25 samples of water were collected from various locations of the Padma River and analyzed for radon concentration using the RAD H2O (DURRIDGE) radon monitoring device. The radon concentrations were found in the range from 0.077 ± 0.036 to 0.494 ± 0.211 Bq/L with a mean of 0.250 ± 0.093 Bq/L. All the concentrations were found to be below the recommended limits of WHO (100 Bq/L) and USEPA (11.1 Bq/ L). The mean annual effective dose due to the radon exposure via inhalation and ingestion pathways were 0.638 mSv/y and 0.629 mSv/y, respectively, which were all well below the annual effective dose recommended by WHO (0.1 mSv/y). Since Bangladesh lacks a national safety limit of radon in water, this pioneering study provides baseline data on radon levels for the environment around Rooppur Nuclear Power Plant.

Assessment of radionuclides from coal-fired brick kilns on the outskirts of Dhaka city and the consequent hazards on human health and the environment

Siraz M.M. Mahfuz,Rakib M.D.A.,Alam M.S.,Al Mahmud Jubair,Rashid Md Bazlar,Khandaker Mayeen Uddin,Islam Md. Shafiqul,Yeasmin S. 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.8

In a first-of-its-kind study, terrestrial radionuclide concentrations were measured in 35 topsoil samples from the outskirts of Dhaka using HPGe gamma-ray spectrometry to assess the radiological consequences of such a vast number of brick kilns on the plant workers, general as well as dwelling environment. The range of activity concentrations of 226Ra, 232Th, and 40K is found at 19 ± 3.04 to 38 ± 4.94, 39 ± 5.85 to 57 ± 7.41, and (430 ± 51.60 to 570 ± 68.40) Bq/kg, respectively. 232Th and 40K concentrations were higher than the global averages. Bottom ash deposition in lowlands, fly ash buildup in soils, and the fallout of micro-particles are all probable causes of the elevated radioactivity levels. 137Cs was found in the sample, which indicates the migration of 137Cs from nuclear accidents or nuclear fallout, or the contamination of feed coal. Although the effective dose received by the general public was below the recommended dose limit but, most estimates of hazard parameters surpass their respective population weighted global averages, indicating that brick kiln workers and nearby residents are not safe due to prolonged exposures to terrestrial radiation. In addition, the soil around sampling sites is found to be unsuitable for agricultural purposes.

Computational optimisation of a concrete model to simulate membrane action in RC slabs

Khandaker M. A. Hossain,Olubayo O. Olufemi 한국계산역학회 2004 Computers and Concrete, An International Journal Vol.1 No.3

Slabs in buildings and bridge decks, which are restrained against lateral displacements at the edges, have ultimate strengths far in excess of those predicted by analytical methods based on yield line theory. The increase in strength has been attributed to membrane action, which is due to the in-plane forces developed at the supports. The benefits of compressive membrane action are usually not taken into account in currently available design methods developed based on plastic flow theories assuming concreteto be a rigid-plastic material. By extending the existing knowledge of compressive membrane action, it is possible to design slabs in building and bridge structures economically with less than normal reinforcement. Recent research on building and bridge structures reflects the importance of membrane action in design. This paper describes the finite element modelling of membrane action in reinforced concrete slabs through optimisation of a simple concrete model. Through a series of parametric studies using the simple concrete model in the finite element simulation of eight fully clamped concrete slabs with significant membrane action, a set of fixed numerical model parameter values is identified and computational conditions established, which would guarantee reliable strength prediction of arbitrary slabs. The reliability of the identified values to simulate membrane action (for prediction purposes) is further verified by the directsimulation of 42 other slabs, which gave an average value of 0.9698 for the ratio of experimental to predicted strengths and a standard deviation of 0.117. A ?eflection factor?is also established for the slabs, relating the predicted peak deflection to experimental values, which, (for the same level of fixity at the supports), can be used for accurate displacement determination. The proposed optimised concrete model and finite element procedure can be used as a tool to simulate membrane action in slabs in building and bridge structures having variable support and loading conditions including fire. Other practical applications of the developed finite element procedure and design process are also discussed.

Effect of Rumen Degradable Protein (RDP) in Straw Based Ration on Purine Derivatives Excretion and Microbial Nitrogen Supply in Cattle

Khandaker, Z.H.,Tareque, A.M.M. Asian Australasian Association of Animal Productio 1997 Animal Bioscience Vol.10 No.4

Four local cattle were ($145{\pm}9.7kg$) used in a $4{\times}4$ Latin square design to study the effect of different levels of rumen degradable protein (RDP) in straw based ration on purine derivatives excretion and microbial N supply in cattle. The four rations were formulated at the same amount of energy but varying RDP approximately 50 (U0), 75 (U1), 100 (U2) and 150 (U3) percent levels of RDP requirement for maintenance. They were fed ranged from 101 to 304 g RDP/d. Apparent digestibility of all nutrients increased significantly (p < 0.01) in cattle fed ration U2 than other rations. Rumen $NH_3-N$ concentration increased from 43 to 130 mg/l in response of RDP intake. Purine derivatives excretion increased significantly (p < 0.01) with incremental level of 203 g RDP/d (U2) intake and positively correlated (r=0.69, p < 0.01, n=16) with amount of RDP intake. The rates of rumen microbial N supply were 16.8, 27.2, 39.1 and 32.9 g/d for rations U0, U1, U2 and U3 respectively. Efficiency of microbial N supply (EMNS) per kg of DOMR were 19.0, 25.3, 33.0, and 28.6 g and per MJ of ME. Intake were 0.62, 1.00, 1.44 and 1.21 g for U0, U1, U2 and U3 respectively and highest results were obtained in cattle fed U2 ration. Results of this study suggest that PD excretion and EMNS were increased as incremental level of RDP intake (U2) in local cattle.

STUDIES ON PROTEIN DEGRADABILITIES OF FEEDSTUFFS IN BANGLADESH

Khandaker, Z.H.,Tareque, A.M.M. Asian Australasian Association of Animal Productio 1996 Animal Bioscience Vol.9 No.6

This experiment was conducted to determine RDP values of locally available feedstuffs that are commonly used in ruminant rations in Bangladesh. Four cattle were fistulated in the rumen for the in situ nylon bag studies. Seventeen different feedstuff sample (9 roughages and 8 concentrates) were evaluated in $4{\times}14cm$ nylon bags and incubated in the rumen for different periods of time (2, 6, 12, 24, 48 and 72 h). The variation in crude protein (CP) contents reflected on the average CP disappearance value throughout the rumen incubation. Soluble fraction (a), insoluble but degradable fraction (b) along with the rate of degradation also varied widely among the various feedstuffs. Under 2% of rumen outflow rate, the percentages of the calculated protein degradabilities of roughages were rice straw, 16.7; maize grass, 70.6; oat grass, 70.8; dhal grass, 71.1; sunhemp, 78.4; napier grass, 62.4; matikalai grass, 72.1; khesarikalai grass, 76.9 and daincha browse, 78.4, respectively. The results in the protein degradabilities (%) in 8% ruminal outflow rate of concentrates were wheat bran, 61.6; rice polish (red), 61.3; rice polish (auto), 30.9; mustard oil cake, 71.8; sesame oil cake, 74.2; coconut oil cake, 57.9; soybean meal, 49.2 and fish meal, 37.9, respectively.

Excitation Functions for the ²⁷Al(p, x)^22,24Na Nuclear Reactions up to 40 MeV

M. U. Khandaker,K. Kim,M. W. Lee,K. S. Kim,G. N. KIM 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

Excitation functions for the ^(nat)Al(p, x)^(22,24)Na nuclear processes were measured in the proton energy range of 30 - 38 MeV using a stacked-foil activation technique combined with a high purity germanium (HPGe) γ-ray spectrometry. Measured data were compared with the available literature data and theoretical calculation by the TALYS code. Validation of the measured data was done with the IAEA recommended ones.

Artificial neural network model for the strength prediction of fully restrained RC slabs subjected to membrane action

Khandaker M. A. Hossain,Mohamed Lachemi,Said M. Easa 한국계산역학회 2006 Computers and Concrete, An International Journal Vol.3 No.6

This paper develops an artificial neural network (ANN) model for uniformly loaded restrained reinforced concrete (RC) slabs incorporating membrane action. The development of membrane action in RC slabs restrained against lateral displacements at the edges in buildings and bridge structures significantly increases their load carrying capacity. The benefits of compressive membrane action are usually not taken into account in currently available design methods based on yield-line theory. By extending the existing knowledge of compressive membrane action, it is possible to design slabs in building and bridge decks economically with less than normal reinforcement. The processes involved in the development of ANN model such as the creation of a database of test results from previous research studies, the selection of architecture of the network from extensive trial and error procedure, and the training and performance validation of the model are presented. The ANN model was found to predict accurately the ultimate strength of fully restrained RC slabs. The model also was able to incorporate strength enhancement of RC slabs due to membrane action as confirmed from a comparative study of experimental and yield line-based predictions. Practical applications of the developed ANN model in the design process of RC slabs are also highlighted.

Influence of extreme curing conditions on compressive strength and pulse velocity of lightweight pumice concrete

Khandaker M. Anwar Hossain 사단법인 한국계산역학회 2009 Computers and Concrete, An International Journal Vol.6 No.6

The effect of six different curing conditions on compressive strength and ultrasonic pulse velocity (UPV) of volcanic pumice concrete (VPC) and normal concrete (NC) has been studied. The curing conditions include water, air, low temperature (4℃) and different elevated temperatures of up to 110℃. The curing age varies from 3 days to 91 days. The development in the pulse velocity and the compressive strength is found to be higher in full water curing than the other curing conditions. The reduction of pulse velocity and compressive strength is more in high temperature curing conditions and also more in VPC compared to NC. Curing conditions affect the relationship between pulse velocity and compressive strength of both VPC and NC.