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3.527 (31-40)
NaslovThe hyperspace of totally disconnected sets / Raúl Escobedo, Patricia Pellicer-Covarrubias, Vicente Sánchez-Gutiérrez.
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OpisIn this paper we study the hyperspace of all nonempty closed totally disconnected subsets of a space, equipped with the Vietoris topology. We show results of compactness, connectedness and local connectedness for this hyperspace. We also include a study of path connectedness, particularly we prove that for a smooth dendroid this hyperspace is pathwise connected, and we present a general result which implies that for an Euclidean space this hyperspace has uncountably many arc components.
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31
NaslovApproximate inverse limits and (m,n)-dimensions / Matthew Lynam, Leonard R. Rubin.
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OpisIn 2012, V. Fedorchuk, using m-pairs and n-partitions, introduced the notion of the (m,n)-dimension of a space. It generalizes covering dimension. Here we are going to look at this concept in the setting of approximate inverse systems of compact metric spaces. We give a characterization of (m,n)-dim X, where X is the limit of an approximate inverse system, strictly in terms of the given system.
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32
NaslovAn algebraic framework for multi-objective and robust variants of path problems / Robert Manger.
Materijalni opisIlustr.
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OpisIt is well known that various types of path problems in graphs can be treated together within a common algebraic framework. Thereby each type is characterized by a different ``path algebra", i.e., a different instance of the same abstract algebraic structure. This paper demonstrates that the common algebraic framework, although originally intended for conventional problem variants, can be extended to cover multi-objective and robust variants. Thus the paper is mainly concerned with constructing and justifying new path algebras that correspond to such more complex problem varieties. A consequence of the obtained algebraic formulation is that multi-objective or robust problem instances can be solved by well-known general algorithms designed to work over an arbitrary path algebra. The solutions obtained in this way comprise all paths that are efficient in the Pareto sense. The efficient paths are by default described only implicitly, as vectors of objective-function values. Still, it is shown in the paper that, with slightly extended versions of the involved algebras, the same paths can also be identified explicitly. Also, for robust problem instances it is possible to select only one ``robustly optimal" path according to a generalized min-max or min-max regret criterion.
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33
NaslovCamouflage fabric - fabric for today's competitive era / Madan Lal Regar, Akhtarul Islam Amjad, Atiki Singhal.
Materijalni opisIlustr., graf. prikazi.
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OpisInnovation is the foremost requirement of today’s competitive era. Innovation refers to improving on an existing concept or idea using a stepwise process to create a commercially viable product. Food, clothing, and shelter are the basic needs of a human being. Clothing is made from textiles; with the help of textiles, the shelters are made more comfortable and attractive. Traditionally, fabrics are used for apparel and home furnishing purpose, but these days, application is diversifying in order to satisfy technical and protective functions. Camouflage fabrics are the ones most suitable for technical and protective purposes. Over the past few years, researchers have put emphasis on the development of camouflage fabrics for security measures for troops, and for activities intended to hide facts and mislead the enemy. Years of investigations have been invested into innovation in the manufacture of these fabrics which are providing the ultimate performance and reliability. In this review paper, an attempt is made to comprise principle, manufacturing techniques, properties and application. This paper also highlights the modern development and recent trends in the field of camouflage fabric. Camouflage and multispectral universal camouflage are the main areas of recent trends on camouflage fabrics. Camouflage fabrics are mostly used for hunting, survival prepper, tactical and military protective wears.
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34
NaslovCharacterizati on of sisal/polypropylene composites treated with plasma / B. A. Muralidhar.
Materijalni opisIlustr., graf. prikazi.
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OpisIn this study, sisal/polypropylene composites were experimentally investigated for their flexural, thermal and water absorption characteristics. The effect of oxygen (O), argon (Ar) and ammonia (NH3) plasmas on the surface of the sisal fibre as well as the effect of the sisal fibre content on the above mentioned properties was studied. The composite laminates (4 mm thick) were processed by hand lay-up technique by using a compression moulding machine, with the mould temperature of 165oC and the pressure of 6.89 x 102 kPa for 15 minutes. Specimen preparation and testing were carried out as per ASTM standards. Flexural data obtained showed that the plasma-treated sisal fibre-reinforced polypropylene offered superior flexural properties compared to untreated laminates, which indicated better adhesion between the sisal fibre and the untreated polypropylene matrix. Thermal investigations revealed that the sisal/polypropylene composite had its thermal stability in between that of the fibre and the matrix. Furthermore, the water absorption studies indicated that plasma treatment decreased the water uptake of the laminates, thereby leading to better fibre-matrix adhesion. Morphological studies were carried out by using SEM to complement the results.
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35
NaslovEnzyme-accelerated acid hydrolysis of untanned proteinaceous wastes from tanning industry / Md. Nur-E-Alam, Nasifa Akter, Kanish Fatema, Md. Abul Kashem Azad, Shimul Chakma, Md. Anwar Arfi en Khan.
Materijalni opisIlustr., graf. prikazi.
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OpisTraditionally, tanning industry has been producing considerable amounts of solid wastes, which raises serious concerns on account of their environmental impact. Out of these, untanned raw trimmings account for about 5-7% of the total quantity of raw materials processed. This waste could be a value-added cheap source of collagen, which has numerous industrial applications if properly and scientifically utilized. This research work deals with the utilization of raw trimmings of solid waste from tanneries in the process of enzymatic hydrolysis, performed by using acetic acid and protease, in order to obtain protein hydrolysate. The hydrolysis was carried out with varying acid concentrations, acid solutions, temperatures and times. The maximum obtained protein hydrolysate was about 88% at 1.5 M acid concentration, 4% enzyme ratio, and 60 °C.
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36
NaslovStudy on comparative analysis of basic woven fabrics produced in air-jet loom and determining structure for optimum mechanical properties and production / Md. Nurunnabi, Jubayer Ibn Haris, Fairooz Raisa Mridula.
Materijalni opisGraf. prikazi.
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OpisThis analysis was directed at dissecting the impact of the structure of the fabric on different properties of the fabric, for example tear strength, tensile strength, shrinkage, elongation, skewness, and so on. The work demonstrated how various structures of the fabric influence these properties. Fabrics with a fundamental woven structure, namely plain, twill, satin and a couple of their subsidiaries, were produced to explore the influence of the structure on different properties of the fabric. The examination built up an approach to gauge the mechanical conduct of the fabric dependent on its structure. The exploration accentuated the structure and detail of the fabric to decide the underlying driver of the change in the mechanical conduct. The properties of the fabric, such as tear strength, tensile strength, elongation, shrinkage and skewness, were extraordinarily affected by the structure of the fabric. It likewise demonstrated to having more noteworthy mechanical properties for firmly interwoven structures, such as plain and twill. The analysis led to the conclusion that the plain structure has the best mechanical properties among different structures.
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37
NaslovChromium adsorption on banana rachis adsorbent from tannery wastewater : optimization, isotherm, kinetics and desorption studies / Sofia Payel, Md. Abul Hashem, Mrinmoyee Sarker, Md. Shahruk Nur-A-Tomal.
Materijalni opisGraf. prikazi.
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OpisThis study investigates the banana rachis adsorbent for adsorption characterization, removal, and recovery of the chromium ion from the chrome tanning wastewater. The batch analysis was conducted to find out an adsorbent dose, contact time, relative pH of the aqueous solution, and initial and final chromium value in the filtrate. The equipped adsorbent was studied by the Fourier transform infrared spectroscopy (FT-IR) analysis to reveal the associated functional groups during adsorption. Batch adsorption examination reveals the optimum conditions of 3 g adsorbent input for 75 mL wastewater at 15 min contact time. The adsorption mechanism showed chromium removal 99.64% with the obtained reduction of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and chloride (Cl-) 96.65%, 93.18%, and 59.62%, respectively. The adopted method followed the pseudo-second-order kinetics and Freundlich isotherm for physical adsorption. Primary desorption studies exhibit a scope for the reuse of chromium from the adsorbed adsorbent. Moreover, in comparison with other studies, the study discloses that banana rachis might be utilized as a feasible adsorbent to be adopted in industrial wastewater treatment, especially chrome tanning wastewater in the tannery.
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NaslovEvaluating suitability of glutaraldehyde tanning in conformity with physical properties of conventional chrome-tanned leather / Md. Minhaz Uddin,, Md. Jawad Hasan, Yead Mahmud, Fatema Tuj-Zohra, Sobur Ahmed.
Materijalni opisIlustr., graf. prikazi.
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OpisLeather manufacturing involves a number of unit processes, out of which tanning is the most important in so far as it converts the putrescible hides/skins into non-putrescible leather. In this study, glutaraldehyde has been exploited as a means to reduce the use of basic chromium sulfate for the production of quality shoe upper crust leather. The paper consists in studying the physical properties of aldehyde-tanned leather and chrome-tanned leather. The aim is to find out the possibility of replacing the wet-blue leather, containing Cr(III) salts, with the glutaraldehyde-tanned wet-white leather. The physical properties of the aldehyde-tanned leather were evaluated, analyzed and compared with the conventional chrome-tanned shoe upper crust leather. Statistical analysis illustrated that the tensile strength, the percentage of elongation, stitch tear strength, Baumann tear strength and grain crack strength of the leather was 211±1 kg/cm2, 38±0.5 %, 89±0.11 kg/cm, 63±0.4 kg/cm and 23±0.4 kg respectively. It was observed that the property of the experimental leather was quite comparable with the conventional chrome-tanned leather and able to meet the requirements of the shoe upper crust leather after re-tanning. The shrinkage temperature of the experimental tanned leather was found to be 87 °C,lower than that of corresponding control, which indicates lesser tanning power of aldehyde. However, the morphology of the aldehyde-tanned leather was quite akin with the conventional leather. This study suggests that using glutaraldehyde in the tanning process in order to minimize the chromium load in the tanning and the re-tanning process during the production of shoe upper crust leather reduces the generation of toxic waste and its impact on the environment.
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NaslovSynthesis and application of graphene oxide (GO) for removal of cationic dyes from tannery effluents / Md. Israil Hossain,, Amal Kanti Deb, Md. Rayhan Sarker, A. A. Shaikh, Manjushree Chowdhury,, Md. Zakir Sultan.
Materijalni opisIlustr., graf. prikazi.
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OpisThe increasing demands for dye in tanning industries have resulted in unconstrained throwing away of dyes into water bodies causing enormous environmental pollution. The removal of these dyes from effluents is mandatory and needs the recommendation of the latest technology and less expensive processes in this regard. Graphene oxide (GO) was prepared, characterized, and applied in the process of removal of cationic dye. GO was characterized by FTIR, X-RD, SEM, and TGA and the following functional groups were found: –COOH, OH, -C=O, and C-O-C. Basic Blue 3 (BB 3) was used as a model synthetic cationic dye. The dye adsorption studies were carried out in terms of the adsorbent dose, the pH, initial dye concentrations, and contact time. The removal efficiency for BB 3 was found to be 100% dye concentration up to 600 ppm at pH 7 with 10 mg (0.1g/L) of the adsorbent, GO, within 6 minutes. In the case of real tannery effluents, the eradication efficiency was found to be 91.2%. The results revealed that GO was a suitable adsorbent for the removal of cationic dyes from tannery effluents.
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3.527 (31-40)