Daffodil International University Research Articles

A computational method for fuzzy arithmetic operations

In this paper, a computer implementation to evaluate the arithmetic operations on two fuzzy numbers with linear membership functions has been developed. The fuzzy arithmetic approached by the interval arithmetic is used here. The algorithm of the developed method with a numerical example is also provided. Using this method four basic arithmetic operations between any two TFNs can be evaluated without complexity. Keywords: Fuzzy arithmetic, Fuzzy number, Membership Function, Interval arithmetic, α - cut. DOI: 10.3329/diujst.v4i1.4350 Daffodil International University Journal of Science and Technology Vol.4(1) 2009 pp.18-22

Experimental investigation on roling-sliding contact properties of WC cermet coatings

In this study, tribological properties of Hi-HVOF sprayed WC-Cr-Ni cermet coatings were investigated experimentally under lubricated rolling-sliding contact. Coatings were deposited onto the induction hardened carbon steel and carburized hardened steel materials. Substrate surfaces were prepared by axially grinding, blasting and circumferentially grinding. Under the operating conditions of contact pressure PH=1.4 GPa and slip ratio s=-28.0%, the effects of substrate hardness and substrate surface kind on the tribological properties of the cermet coating were examined. It was found that cermet coating showed a long life and durability was not influenced by the substrate hardness and substrate surface kind. It was also found that during the running-in process, oil film formation was hardly influenced by the substrate hardness and substrate surface kind. On the other hand, surface hardness and surface roughness of the coating were more influenced in the case of circumferentially ground substrate than that in the case of axially ground or blasted substrate. In addition, coating material loss was very high in the case of circumferentially ground substrate when the substrate material was induction hardened carbon steel. Keywords: Tribological Properties, WC-Cr-Ni Cermet, Substrate Hardness, Substrate Surface Kind DOI: 10.3329/diujst.v4i1.4356 Daffodil International University Journal of Science and Technology Vol.4(1) 2009 pp.50-56

Effect of Blend Ration of Quality Characteristics of Bamboo/Cotton Blended Ring Spun Yarn

The present study reveals the comparison of physical properties of the bamboo/cotton blended yarn with similar 100 % cotton yarn. The bamboo-cotton blend ratios of each category of yarn (30s, 40s and 50s) were 67:33, 50:50, and 33:67, respectively. For each individual count of yarn, it was observed from the test result that the properties of 50:50/bamboo: cotton blended yarn showed very nearer property to the 100% cotton yarn. For Count (30s), 67:33/bamboo: cotton showed very closer property to the 50:50/bamboo: cotton blended yarn. It was also observed that for each count of yarns, which showed decreasing property with the increase of bamboo in the blend. The quality characters depend upon the ratio of bamboo and cotton in the blend. Keywords: Blending; Yarns; Bamboo/Cotton ratio; Ring spun yarn; Physical Properties DOI: http://dx.doi.org/10.3329/diujst.v7i1.9645 Daffodil International University Journal of Science and Technology Vol.7(1) 2012 34-37

Effect of weft parameters on weaving performance and fabric properties

Threads per inch and yarn count are some of the most important parameters that affect both weaving performance and fabric property. Experimental studies were conducted by weaving fabrics with three different picks per inch (PPI) and weft counts. The study shows that weaving performance is affected by the too high cover factor. Cover factor was calculated by dividing the threads/inch by the square root of the English cotton count and end breakage was taken as an indication of weaving performance. It was observed that when the count as well as threads/inch of one series of yarn changes the crimp% i.e. the consumption of both series of yarns are affected. It was also observed that, as expected, when the threads/inch increases the fabric strength also increases but at higher threads/inch the gain in strength is relatively more. Keywords: Threads, cover factor, EPI, PPI, crimp, strength, weaving performance DOI: 10.3329/diujst.v4i2.4369 Daffodil International University Journal of Science and Technology Vol.4(2) 2009 pp.62-69

Speech recognition front-end for segmenting and clustering continuous Bangla speech

This research is concerned with the development of speech recognition front-end for segmenting and clustering continuous Bangla speech sentence to some predefined clusters. From the study of different previous research works it was observed that the front-end is an important part of any speech recognition system. In our work, the original speech sentences were recorded and stored as RIFF (.wav) file format. Then a segmentation approach was used to segment the continuous speech into uniquely identifiable and meaningful units. Among the different techniques, the word/sub-word segmentation is simple and produces very good results. This is why this technique was selected for speech segmentation to obtain improved performance. After segmentation, the segmented words were clustered into different clusters according to the number of syllables and the sizes of the segmented words. The test database contained 758 words/sub-words segmented from 120 sentences. Each sentence was recorded from six different speakers and saved as a different wave file. The developed system achieved the segmentation accuracy rate at about 95%. Keywords: Front-end, Phonemic and Word segmentation, Clustering, End Point Detection. DOI: 10.3329/diujst.v5i1.4384 Daffodil International University Journal of Science and Technology Vol.5(1) 2010 pp.67-72

Impact of consistent fibre properties on optimization of fabric barré

Cotton is a natural fibre. It's growth depends upon the seasonal weather, climate condition and affection of paste and insects. So the properties of cotton fibres vary not only from lot to lot but also in same lot. The properties such as Micronaire, color grade, maturity measure the ability of dye absorbency of fibre. So if there is high variation of these properties in cotton then a significant variation of dye absorbency in fabric is observed. So the fabric, made form cotton yarn having inconsistent properties, generate complain of barré marks known as patta to our local people. To eliminate or minimize the problem of barré we must have to ensure the uniform distribution of cotton properties throughout the yarn manufacturing stages. And Bale Management is the procedure of determining mix laydowns by maintaining an appropriate combination of cotton properties with consistency through several mixes. Short and long term variation of fibre properties with in and between mixes is responsible for fabric barré which is possible to avoid by bale management. Keywords: Barré, micronaire, color grade, immaturity, mixing, laydown. DOI: 10.3329/diujst.v4i2.4367 Daffodil International University Journal of Science and Technology Vol.4(2) 2009 pp.53-58

Effect of graphical method for solving mathematical programming problem

In this paper, a computer implementation on the effect of graphical method for solving mathematical programming problem using MATLAB programming has been developed. To take any decision, for programming problems we use most modern scientific method based on computer implementation. Here it has been shown that by graphical method using MATLAB programming from all kinds of programming problem, we can determine a particular plan of action from amongst several alternatives in very short time. Keywords: Mathematical programming, objective function, feasible-region, constraints, optimal solution. DOI: 10.3329/diujst.v5i1.4379 Daffodil International University Journal of Science and Technology Vol.5(1) 2010 pp.29-36

One-dimensional finite element discretization of crack propagation through parallel computation

In this study, a new approach of the application of finite element method is presented, to solve the initial stages of crack propagation problems which mean the deformation due to the stress and strain of a material. In early applications of the finite element method for the analysis of crack propagation, the crack-tip motion was modelled by discontinuous jumps. We have implemented one dimensional finite element discretization to solve crack propagation problem. The parallel algorithm with parallel computer system has been used in order to perform the computational analysis of finite element for this study. Parallel Virtual Machine (PVM) has been used as a message passing software with Parallel Computer System. The result of this study will be useful in the mathematics and engineering fields. In mathematics, the research will widen the application of finite elements in solving the engineering science problems. Keywords: Finite Element Method (FEM), Crack Propagation, Parallel computation, Parallel Virtual Machine (PVM). DOI: 10.3329/diujst.v5i1.4378 Daffodil International University Journal of Science and Technology Vol.5(1) 2010 pp.19-28

Grafting of n-butyl acrylate with natural rubber latex film by gamma radiation: a reaction mechanism

Natural rubber latex (NRL) and n-butyl acrylate (n-BA) were blended and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The stabilizing effect was determined by measuring the pH and viscosity of NRL with n-BA with the storage time of five weeks. The cross-link density, swelling ratio of the radiation vulcanized rubber film were measured. The cross-link density of the n-BA grafted NRL film was found increasing and the swelling ratio of that film decreasing with the increased absorbed dose. The optimum radiation dose for better cross-linking of natural rubber latex blended with five parts per hundred rubber (phr) n-BA was found 15 kGy absorbed dose. Based on the cross-linking properties a probable cross-linking reaction mechanism for the n-BA grafted natural rubber latex film was developed. Keywords: Natural rubber latex, n-butyl acrylate, Irradiation, Swelling ratio, Cross-link, Reaction mechanism. DOI: 10.3329/diujst.v5i1.4386 Daffodil International University Journal of Science and Technology Vol.5(1) 2010 pp.81-88

A comparative study of the methods of solving non-linear programming problem

The work present in this paper is based on a comparative study of the methods of solving Non-linear programming (NLP) problem. We know that Kuhn-Tucker condition method is an efficient method of solving Non-linear programming problem. By using Kuhn-Tucker conditions the quadratic programming (QP) problem reduced to form of Linear programming(LP) problem, so practically simplex type algorithm can be used to solve the quadratic programming problem (Wolfe's Algorithm).We have arranged the materials of this paper in following way. Fist we discuss about non-linear programming problems. In second step we discuss Kuhn- Tucker condition method of solving NLP problems. Finally we compare the solution obtained by Kuhn- Tucker condition method with other methods. For problem so consider we use MATLAB programming to graph the constraints for obtaining feasible region. Also we plot the objective functions for determining optimum points and compare the solution thus obtained with exact solutions. Keywords: Non-linear programming, objective function ,convex-region, pivotal element, optimal solution. DOI: 10.3329/diujst.v4i1.4352 Daffodil International University Journal of Science and Technology Vol.4(1) 2009 pp.28-34

ASL characters recognition using person specific subspace method

This paper presents a person-specific subspace method for ASL characters recognition. To implement this person specific subspace method for ASL characters recognition the system first recognizes the faces and then uses skin-color segmentation method for hand poses segmentation. From the segmented hand poses the system recognizes ASL characters using both PCA and person-specific subspace method separately. Experiment result shows that the classification accuracy of person-specific subspace method is better than general PCA method. The experiment result also shows that person-specific subspace method is faster than general PCA method. Key Words: ASL character, Face recognition, PCA, Person-specific subspace method DOI: 10.3329/diujst.v4i2.4366 Daffodil International University Journal of Science and Technology Vol.4(2) 2009 pp.39-52

An algorithm for solving minimum edge-ranking spanning tree problem on partial k-trees

An edge-ranking of a graph G is a labeling of its edges with positive integers such that every path between two edges with the same label i contains an intermediate edge with label j>i. The minimum edge-ranking spanning tree problem is to find a spanning tree of a graph G whose edge-ranking needs least number of ranks. In this paper, we present an algorithm to solve the minimum edge-ranking spanning tree problem on a partial k-tree G in O(n2Δ(k+1)+2 Δk(k+1)+2 log2 k(k+1)+2n) time, where n is the number of vertices, Δ is the maximum vertex degree of the graph G and k is bounded by a constant value. Keywords: Algorithm, partial k-trees, edge-ranking, spanning tree. DOI: 10.3329/diujst.v4i1.4347 Daffodil International University Journal of Science and Technology Vol.4(1) 2009 pp.1-8

Acceleration of vortex methods calculation using MDGRAPE-2 and MDGRAPE-3: A comparative study

The calculation of vortex method has been accelerated by using special-purpose computers, MDGRAPE-2 and MDGRAPE-3, respectively. The similar algorithm has been implemented and the improvement in speed of MDGRAPE-2 was 100 times while MDGRAPE-3 was 1000 times faster when compared with the ordinary PC Xeon 5160(3.0GHz) for N=106. In addition, the speed of MDGRAPE-3 was 25 times faster compared with MDGRAPE-2. The round off errors have been investigated in both cases. Keywords: Vortex Method, Special-Purpose Computer, MDGRAPE-2, MDGRAPE-3, Scaling Error DOI: 10.3329/diujst.v4i1.4351 Daffodil International University Journal of Science and Technology Vol.4(1) 2009 pp.23-27

Effect of washing on weight and strength of mechanically produced blended and 100% cotton curtain

A research had been taken to find out the suitability of blended curtain in respect to the property of 100% similar cotton curtain. Here, two main factors viz. wt. and strength are taken in to account considering the effect of washing on it. From the test results, it is shown that 50:50/ jute: cotton blended curtain is comparable to the 100% cotton curtain of Tk. 90 /meter. Even better than the properties of 100% cotton curtain of Tk. 60/ meter. Keywords: Jute, Cotton, Washing, Strength, Blended, Mechanical, Weight, Curtain. DOI: 10.3329/diujst.v5i1.4373 Daffodil International University Journal of Science and Technology Vol.5(1) 2010 pp.1-5

Effect of spindle speed on textile properties and productivity of fine jute yarn

Spindle speed is an important parameter for the production of jute yarn [1]. An Apron Draft spinning frame was modified in to ring system by incorporating rings and travelers instead of flyers. The experiments were performed for investigating the effect of spindle speed on textile properties and productivity of jute yarn of 103 tex. The spindle speed was varied from 5000 rpm to 9000 rpm. The experiments were performed with Bangla White B (BWB) grade jute sliver of finisher drawing of linear density 2415 tex (70 lb/spy). The draft ratio and the twist used in the experiments were 23 and 240 tpm (turns per meter) respectively. The ring size was KW (4) 76 mm Ø. Steel travelers number 1, Type G, semicircular in shape were used in the experiment. Ten runs were performed for the experiment at the standard atmospheric condition, 20 ± 2°C, and relative humidity 65% ± 2%. The nominal count of the yarn produced was 103 tex. The yarns produced through the experiments were tested for different textile properties. Analysis of the test results shows that the spindle speed greatly influences the textile properties, such as strength, elongation, yarn breakage, productivity, quality ratio etc. of produced yarn. In consideration of the productivity, quality and other textile properties of the yarn, the optimum spindle speed was determined for the production of fine jute yarn of 103 tex. Key Words: Apron draft, spindle speed, fine jute yarn. DOI: 10.3329/diujst.v4i2.4358 Daffodil International University Journal of Science and Technology Vol.4(2) 2009 pp.1-5

Uses of natural fruit (<i>Diospyros embrypteris Pers</i>) as a rot-proofing agent

Two different types of hessian fabrics (sized and desized) were treated with unripe natural fruit juice ( Botanical Name: Diospyros embrypteris Pers) and copper sulphate solution. The physico-chemical properties of the treated fabrics were determined and made nursery pots for seedling to improve the longevity of rot-proof nursery pot. It was observed that 5% copper sulphate solution treated nursery pots posseses longevity 5.5 months but the extract of natural fruit juice mixed with 5% copper sulphate solution treated sample increases the longevity of nursery pot about eleven months. At the same time 8% copper sulphate solution treated nursery pots longevity more than nine months but natural fruit juice mixed with 8% copper sulphate solution treated nursery pot is required to achieve longevity about fourteen months. Uses of natural fruit gaab have no critical steps to environment, free from health hazard and durable. That's why it has some potentiality to use for making nursery pots with less chemical materials. Keywords: Rot-proof, Gaab, Copper sulphate, Longevity, Nursery Pot, Hessian, Sized, Desized DOI: 10.3329/diujst.v4i1.4349 Daffodil International University Journal of Science and Technology Vol.4(1) 2009 pp.14-17

Volumetric and viscometric studies on electrolytes in non-aqueous solvent

The densities, ρ and viscosities, η of NH4Cl, NiCl2 and FeCl3 in dimethylsulfoxide were studied as a function of concentration. The partial molal volume, (φ0v) of these electrolytes were evaluated. The viscosity and viscosity-coefficients (A and B) were also determined by Jones-Dole equation. B-coefficient for NiCl2 and FeCl3 are positive that show structure making behavior in all the solutions while those of NH4Cl are negative indicating structure breaking properties. The coefficient A represents the solute-solute interactions coupled with size and shape effect of the solute and to some extent solute-solvent interactions. The behaviors of three solutes in binary systems were discussed in terms of the charge, size and hydrogen bonding effect. Keywords: Density, Apparent and partial molal volume, viscosity coefficient. DOI: 10.3329/diujst.v4i2.4360 Daffodil International University Journal of Science and Technology Vol.4(2) 2009 pp.15-18

Identification and impact analysis of invasive species: A case study in the Mongla Sea Port Area of Bagerhat District of Bangladesh

Manipulation through invasion is a major problem in most of the port areas in recent world. Mongla is an important sea port that has accomplished the activities like import and export of various goods inside and outside Bangladesh. The process not only involves the moving of goods, it also carries the invasive species purposely or accidentally which invading to the new location of the Mongla port area through exploration and colonization with varieties diversity and scale. The paper identifies the invasive species and analyses the causes and ways of invasion in the coastal waters with possible impacts of invasion in the Mongla Port area. To achieve the objectives of the research, different aquatic species were collected by random sampling from the confluence of the River Passur Mongla port and the adjacent area around the Sundarbans from September 2006 to April 2007. The fishermen and local communities including indigenous people were interviewed to explore the invasion situation. The research reveals that ballast water of cargo ships is one of the means of invasion of the coastal waters of Mongla Port. Aquaculture is another reason of invasion due to introduction of many exotic fishes and shrimp species such as Pangus (Pangasius sutchi), African Magur (Clarias gariepinus), Tilapia (Tilapia mossambica) and Nilotica (Oreochromis niloticus) etc. that have the active roles for altering the aquatic ecosystem of Mongla Port. Finally, the research also finds out some possible environmental impacts caused by those invasive species. Key words: Invasive species, Aquaculture, Indigenous species, Aquatic ecosystem, Ballast water DOI: 10.3329/diujst.v4i1.4353 Daffodil International University Journal of Science and Technology Vol.4(1) 2009 pp.35-41

Production of jute yarns with low content of unsaponifiable matters

Castor oil having low content of unsaponifiable matters was chosen for the development of new jute batching emulsion processes. The suitability of the castor oil was also assessed in terms of its favourable colour, odour, specific gravity, acid value, iodine value, saponification value, viscosity, pour points and flash points in comparison to those of conventional JBO. Different recipes for the production of emulsions were standardized in the industrial scale and their suitability were assessed according to their stability, specific gravity, temperature, viscosity and pour points. The recipes were used to spin jute fibre in the jute mill machines. The yarn products were studied to evaluate their work performances based on their physico-chemical properties: moisture regain, t.p.i., W.I., count, strength, tenacity, extension, textile modulus, toughness, QR, oil content and unsaponifiable matters. The yarn products were particularly evaluated in terms of their unsaponifiable matters based on the IJSG criterion. The yarns of processes show quality ratio 93.93 to 104.20 and unsaponifiable matters ranging from 126.05 to 414.92 mg/kg yarn and easily pass the IJSG criterion. The processes therefore appear to be of commercial importance. Key words: Food items, IJSG criterion, JBO, Jute sacks, Unsaponifiables, Vegetable oils. DOI: 10.3329/diujst.v5i1.4376 Daffodil International University Journal of Science and Technology Vol.5(1) 2010 pp.10-18

Antifungal activity of mixed ligand transition metal complexes of some dibasic acid and heterocyclic bases

Mixed ligand transition metal complexes of Cu (II), Co (III), Rh (III) and Pt (IV) ions with dibasic acids viz., diphenic acid and adipic acid as primary ligands and amine bases as secondary ligands have been synthesized. Their conventional physical and chemical analyses have been done. The antifungal activities have been evaluated by Disc Diffusion method employed for antifungal assays against two pathogenic fungi. All the complexes show moderate antifungal activity. The highest inhibition of growth occurred on complex [Cu (DA)(8-HQ)] against the fungi Botryodiplodia theobromae and the lowest on complex [Rh (DA)(8-HQ)(H2 O)2] against the fungi Colletotrichum gloesparioides penz. Key words: Biological Activity, diphenic acid, heterocylic amine, mixed ligand complexes DOI: 10.3329/diujst.v4i1.4357 Daffodil International University Journal of Science and Technology Vol.4(1) 2009 pp.57-59