Volume 2 Issue 1

Authors: Ewa Rudnik

Abstract: The aim of this work was to elucidate factors affecting electroless codeposition of metals with ceramic particles. Codeposition of SiC, SiO2 and Al2O3 particles with Ni-P and Co-P matrixes in citrate-malonate alkaline solutions was compared. The positive surface charge of SiC particles corresponded to increased adsorption of hypophosphite anions, while negatively charged SiO2 and Al2O3 particles showed high adsorption of metal ions. It resulted in high incorporation of the carbide into the metal layers and low percentages of oxides in the coatings. Adsorption of nickel ions on SiC particles was promoted by the presence of maleic acid in the bath, however it did not improve incorporation of the particles into the Ni-P matrix. Equilibrium distribution of the species in the plating baths was also calculated.

Keywords: Electroless Deposition; Nickel; Cobalt; Composite; Surface Charge; Adsorption


Authors: R. Yavari; S. Ramaswami; J. S. Snipes; M. Grujicic

Abstract: Within the present work, the problem of structural integrity (including potential collapse/survivability) of a model building when subjected to a blast attack by a close-proximity vehicle-borne improvised explosive device (VBIED) is investigated using advanced transient, non-linear dynamics, discrete-element modeling (DEM) and simulation computational methods and tools. Since the DEM approach is highly sensitive to the details of the constitutive-material (and contact-interaction) models, a significant portion of the work is devoted to explaining the formulation and the physical basis for the material models used. In particular, since concrete is the key material used in the construction of a building, a critical assessment is provided of the DEM concrete material model employed. To quantify blast-survivability of the building and, in particular, its key structural components, the concept of the so-called design basis threat, DBT (as quantified by the TNT-equivalent charge mass and the associated VBIED standoff distance) is utilized. To help quantify DBT, a parametric study is carried out involving the following design parameters: (a) TNT-equivalent charge mass; (b) VBIED standoff distance; and (c) the degree of concrete reinforcement with steel. The results obtained in the present work also revealed (in a qualitative fashion) the role that the phenomena such as the interaction of the VBIED-induced soil-borne shock waves with the building underground support structure as well as the interaction of the vehicle fragments and the detonation products with the structural elements of the building play in causing damage (and potential collapse) of the building.

Keywords: Discrete Element Modeling (DEM); Concrete Material Modeling; Improvised Explosive Devices (IEDs)


Authors: Noor Mohammad; Q. HamidulBari; M. Mahmudur Rahman; Amimul Ahsan; Habibur Rahman Sobuz; Md. Alhaz Uddin

Abstract: Textile wastewater contains different colors which are harmful to the environment. Activated carbon can be used for the decolorization of textile wastewater. Most of the textile plants in Bangladesh do not use the activated carbon due to its expensive cost and still it is classified as imported item. Low-cost activated carbon produced from locally available materials can solve this problem. This paper describes the color removal of textile wastewater by adsorption process using activated carbon derived from rice husk in a low-cost method. Thermal activation system was applied for the preparation of carbon. The maximum adsorption of color was found at an optimum temperature of 400C with the retention time of 60 minutes. Thus this study demonstrated encouraging performance of activated carbon produced from rice husk compared to the industrial grade activated carbon for decolorization of textile wastewater in the analysis.

Keywords: Activated Carbon; Adsorption; Rice Husk; Textile Wastewater; Decolorization