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K. T. Osman , M. M. Rahman , P. Barua

Abstract

In the present study, a comparison was done between soil properties of forest plantations and adjacent unplanted plots at 14 sites within Chittagong University Campus. The sites were at nearly level topography and the soils were basically uniform with sandy loam to sandy clay loam, moderately to strongly acid, poorly fertile surface. Acacia auriculiformis A. Cunn. Ex. Benth., Eucalyptus camaldulensis Dehnh., Lagerstroemia speciosa (L.) Pers. And Swietenia mahagoni (L.) Jacq. Have been grown for various periods in each of three of the studied sites. In the remaining two sites, there were plantations of Hope a odorata Roxb. Data show that soils under the plantations had significantly higher organic carbon, total N, available K and Mg. On the other hand, both pH and available Ca were lower in soils under plantations than in the adjacent unplanted plots. The difference was more pronounced in the surface soil than the subsoil. The C/N, K/Ca, Mg/Ca and K/Ca + Mg ratios were higher in the plantations indicating substantial removal of N and Ca by the tree crops. However, there was no definite trend of variation in soil properties among the species and among sites within each species. This lack of differences might be due to the younger stage of the plantations.

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K. T. Osman , S. M. S. Haque , M. M. Rahman

Abstract

In the Keochia SiliviculturaI Research Station, Chittagong, Bangladesh, a semi-detailed soil survey was done in 1978. Afterwards plantations of Acacia auriculiformis, Acacia mangium, Eucalyptus camaldulensis and Pinus caribaea were established. The soil were presently analysed for certain physico-chemical properties. It has been found that the organic matter, total N, available K and pH of soils have increased by the plantations.

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M. M. Rahman , M. W. Baksha , J. T. Sterringa

Abstract

This paper deals with the feeding behaviour of purple sunbird, Nectarinia asiatica. The bird eats the fruit of the mistletoes which are parasitic on gamar (Gmelina arborea) and teak (Tectona grandis) and helps in dispersal of mistletoe seeds in plantations of Bangladesh. When mistletoe fruits are not available in nature the bird is found sucking the nectar of an ornamental tree commonly know as Kolkaphul, Thevetia peruviana. The behaviour of the bird in relation to its alternate food sources was studied and discussed with a view to minimize dispersal of mistletoe seeds.

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A. K. M. ParvezIqbal ¹, IshakAris ², M. M. Rahman ¹, NorhisamMisron ²

Affiliations
1 Department of Mechanical Engineering, College of Engineering, Universiti Tenaga Nasional (UNITEN), Jalan IKRAM-UNITEN, 43000, Kajang, Selangor, MY
2 Department of Electrical Engineering, Faculty of Engineering, Universiti Putra Malaysia (UPM), 43400 UPM Serdang, Selangor, MY

Abstract

Pneumatic system is normally used to trigger the automatic spray gun for conventional spray operations. Highly skilled labors and a number of adjustable knobs are required to produce the high quality coating works using the conventional automatic spray gun which is cost intensive. Therefore, linear motor operated multiple spray operations spray gun has been developed. This spray gun consists of two spray units, an air control and supply unit and a triggering unit to carry out the multiple spray operations. This paper focuses on the design optimization and fabrication of the housing of the spray units which hold fluid nozzles, air nozzles, an assembly cap, a needle valve or a ball valve. In the air less and air assisted airless spray systems, high pressurized liquid is passed through the nozzle which is held by the housing of the spray unit. Before entering into the nozzle, the high pressurized liquid is passed through the housing. For the simplicity of the analysis, it is assumed that the housing is an open-ended pressure vessel. From the analysis, dimensions and material selection have been optimized and finally the spray units have been fabricated and tested. During the performance test it is seen that satisfactory transfer efficiency of spray operation has been achieved by using newly developed spray housing of the spray units, which proves the stability of the spray housing during high pressure operation.

Keywords

Spray Gun, Spray Process, Design, Pressure Vessel, Failure Analysis, Deflection Analysis

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A. K. M. Parvez Iqbal ¹, M. M. Rahman ¹

Affiliations
1 Department of Mechanical Engineering, College of Engineering, Universiti Tenaga Nasional, Jalan IKRAM-UNITEN, 43000, Kajang, Selangor D.E., MY

Abstract

A cool box for passenger car refers to a kind of box which is designed and fabricated using well insulating materials in order to ensure the coolness inside the cool box is always stable. The coolness inside of cool box depends on the refrigerant cycles of the car air conditioning system. This cool box has same function as mini fridge to keep fresh foods and beverages but it cannot ensure to freeze the water because the temperature inside of the cool box will be in the range of 12.2oC to 22.1oC which is below the room temperature. This will help to minimize the activeness of bacteria to spoil the foods and beverages at the same time it can linger the duration for food and beverages to spoil. Cool box will help car users to bring food along them when traveling long journey and during the outdoor activities. The linkage system is mainly about connecting extra supplier hose at the receiver dryer section of car air conditioning system in order to intake the refrigerant flow to the cool box and back to connect at tube after evaporator section as outlet. All affecting parameter such as temperature inside the cool box, heat transfer rate, and air ventilation has been studied to design and fabricate the cool box. Finally several tests have been conducted which show that in operating condition inside temperature and relative humidity are suitable to keep the groceries items in fresh condition.

Keywords

Cool Box, Relative Humidity, Temperature, Insulation, Refrigerant

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M. U. Ahammad ¹, M. M. Rahman ², M. L. Rahman ³

Affiliations
1 Department of Mathematics, Dhaka University of Engineering and Technology (DUET), Gazipur-1700, BD
2 2Department of Mathematics, Bangladesh niversity of Engineering and Technology (BUET), Dhaka-1000, BD
3 Department of Mathematics, Rajshahi University, Rajshahi-6205, BD

Abstract

An approach is performed following finite element technique for MHD flow of viscous incompressible and electrically conducting fluid around a heat conducting solid block placed in a ventilated enclosure. A uniform transverse magnetic field is imposed in the opposite direction of flow perpendicular to the right vertical wall. Reynolds number and Prandtl number effects are investigated on flow and thermal field at a wide range of Reynolds (50≤Re≤500) and Prandtl (0.071≤Pr≤7.1) numbers. The expressions for the flow visualizations and temperature distributions inside the studied domain are presented by streamlines and isotherms. Moreover average Nusselt number at the hot wall and average bulk fluid temperature in the cavity are obtained. It is observed that the results focused in this paper are consistent with the physical reality of the flow problem.

Keywords

Reynolds Number, Prandtl Number, Square Enclosure, Mixed Convection, Heat Conduction

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M. M. Rahman ¹, W. Islam ¹, K. N. Ahmed ²

Affiliations
1 Institute of Biological Sciences, Rajshahi University, Rajshahi 6205, BD
2 Bangladesh Council of Scientific and Industrial Research Laboratories, Dhaka 1205, BD

Abstract

Plastanoxus westwoodi (Kieffer), an ectoparasitoid of the larvae and pupae of flat grain beetle, Cryptolestes pusillus (Schoenherr), was evaluated experimentally by infesting 625g kibbled wheat in a plastic container with 100 pairs of the beetles and at 35 days after introducing 0, 5, 10, 20, 30, 40 and 50 mated females of the parasitoids. Samples taken 180 days after the parasitoid was introduced showed P. westwoodi had reduced the population growth of the beetle by at least 43.08% even when only 5 mated females were introduced and by 81.31% when 50 mated females were introduced. The pest emergence was very high in the control container. Minimum pest emergence and maximum parasitism were achieved by introducing 50 mated females per container.

Keywords

Biological Control, Cryptolestes pusillus, Parasitism, Plastanoxus westwoodi and Suppression.

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D. Chakraborti ¹, B. K. Biswas ¹, G. K. Basu ¹, U. K. Chowdhury ¹, T. Roy Chowdhury ¹, D. Lodh ¹, C. R. Chanda ¹, B. K. Mandal ¹, G. Samanta ¹, A. K. Chakraborti ¹, M. M. Rahman ¹, K. Paul ¹, S. Roy ², S. Kabir ², B. Ahmed ², R. Das ², M. Salim ², Q. Quamruzzaman ²

Affiliations
1 School of Environmental Studies, Jadavpur University, Calcutta - 700 032, IN
2 Dhaka Community Hospital, Bara Magh Bazar, Dhaka - 1217, BD

Abstract

The groundwater arsenic contamination in Bangladesh is a phenomenon of surface ero- sion, transportation and deposition in the form of Delta and ∼lood Plain. While dealing with such geomorphological units like Tableland, Flood Plain, Delta and Hill Tract in Bangladesh, we have found the possibility of having huge arsenic contaminattion free groundwater reservoir in selected areas in Bangladesh. The results presented are the outcome of our last 5 years, field survey analysing for arsenic of water of twentyfive thousand eight hundred ninetyseven hand tubewells in sixtyfour districts of Bangladesh comprising four existing geomorphological regions (a) Deltaic region (including coastal region), (b) Flood Plain, (c) Tableland and (d) Hill Tract. In this report, we will highlight (1) the area in Bangladesh where groundwater is not arsenic contaminated and the' possibility to use shallow hand tubewells as potential groundwater resource for drinking purpose and (2) arsenic contaminations scenario of deep tubewells (above 100 meters) all over Bangladesh and suitable depth in arsenic contaminated area to get safe water.

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Naveen Kalra ¹, J. C. Biswas ², M. Maniruzzaman ³, A. K. Choudhury ⁴, S. Akhter ⁴, F. Ahmed ⁴, M. A. Aziz ⁴, M. M. Rahman ⁵, M. M. Miah ⁵

Affiliations
1 Division of Agricultural Physics, Indian Agricultural Research Institute, New Delhi 110 012, IN
2 Bangladesh Rice Research Institute, Gazipur 1701, BD
3 Bangladesh Rice Research Institute, Gazipur 1701, BD
4 Bangladesh Agricultural Research Institute, Gazipur 1701, BD
5 Bangabandhu Sheik Mujibur Rahman Agricultural University, Gazipur 1706, BD

Abstract

Growth of crops obeys certain physiological principles, which have been described, most of the times, in qualitative terms but can be quantified in response to the environment by mathematical formulae by linking the equations to each other. In process, a mathematical model is obtained that can be written as a computer program. Rapid accumulation of knowledge in the agricultural fields and increased accessibility to information technology have contributed to the development of a wide number of agricultural models. Crop simulation models can be used as a tool to assist farmer in their decisions on agronomic and management operations.

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I. U. Karim ¹, M. M. Rahman ²

Affiliations
1 ULAB School of Business, University of Liberal Arts Bangladesh (ULAB), Dhaka, BD
2 School of Public Affairs, University of Science and Technology of China (USTC), Hefei, CN

Abstract

Contributing to advance the discourse of organisational research, literature and sciences, the present study critically maps out the contemporary organisational models (2010-2015) on social sustainability for organisational stakeholders. Under the systematic literature review, research design is based on the SALSA framework. The type of data and analysis of this study are qualitative with high level of inductivity followed by systematic approaches of literature search, creation of literature base comprising of 70 articles thematically, and thus analysing the major 14 models argued by the researchers from critical realist viewpoints revealing important sustainable patterns of the models critically. Undergoing the analysis and synthesis, these organisational models (following model dissections) fit together as per revealed modeling patterns and alignments, of which two major alignments of “relational-group-transformational” and “open-system-RBV-organic” respectively form the leadership (behaviour, scope, focus) and organisation (structure, resources, design) oriented modeling scenario for organisational stakeholders on sustainable management.

Keywords

Leadership, Modeling, Organisation, Organisational Literatures, Organisational Models, Organisational Stakeholders, Social Sustainability, Sustainable Management.

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