Papers by Keyword: Transformation

Abstract: Carbon-based materials are widely used in various fields such as wastewater treatment, gas sensing, and energy storage applications. In this study, waste peanut shell (PSH), available in Egypt, were transformed into useful materials by physical, chemical, and thermal treatments. The physical properties of materials from the different processing combinations were investigated. The activated (APSH), carbonized (CPSH), and activated/carbonized (A/CPSH) forms were successfully prepared. The prepared solids were characterized by SEM, FTIR, XRD, and nitrogen gas adsorption. Ball milling at 5 runs for 45 min resulted in 84 wt% of the ground PSH passing through the 212 μm mesh. Accordingly, the activation, carbonization, and activation/carbonization increased the surface areas of resulting solids by 6, 34, and 580 times, respectively. Among the materials prepared, the activated/carbonized PSH had a mean pore diameter of 1.9 nm, mesoporous material, and the highest electrical conductivity of 0.0042 Ω^-1cm^-1. This PSH is available as adsorbent in water treatment and materials for gas sensing and energy storage.

Abstract: The work considers the main elements of the magneto-dimensional transformation properties in the ultradispersed metallic media (UDM) as a nanomodifier in the process of the formation of nanocompositional polymeric materials (NCPM) based on polyolefins () from a melt. It has been shown that UDM nanoparticles in a melt under the influence and interaction with a thermoplastic matrix are capable of transforming their magnetic properties (to the level of superparamagnetic), structural-dimensional parameters, and chemical potential. With this mutual influence, the nanomodifier has an active effect on the thermoplastic melt at all stages of the formation of the structure-property relationship: structureless ensembles of macromolecules → formation of clusters (domains), lamellas, crystallites → formation of a network of intermolecular entanglements → crystallization of the thermoplastic matrix → transition to a condensed state. An important component of the formation of a fine-crystalline anisotropic NCPM structure is the intramatrix orientation of the structural elements of the thermoplastic in the melt under the influence of the magneto-dimensional transformable manifestations of the nanomodifier. A consequence of the formation of a fine-crystalline anisotropic structure of the NCPM is an increased level of a complex of physicochemical properties (such as deformation-strength, rheological, etc.). An assumption is made about the possibility of the formation of coherent wave packets from clusters (domains) and lamellas of crystallites of matrix thermoplastic with a minimum three-dimensional geometry under the action of superparamagnetic forces of nanoparticles of the nanomodifier.

Abstract: New method of synthesis of biocompatible, biodegradable and nontoxic composite materials based on polysaccharide chitosan and inorganic phosphate component will be presented in this work. Materials structure was changed by in situ transformation of phosphate phases. Transformation of initial precursors to hydroxyapatite as one of the most stable phosphate phase occurred as a result of thermal and alkaline treatment. XRD and SEM methods were applied to investigate structure and morphology of obtained samples.

Abstract: Brushite cement has advantages such as fast setting, high reactivity and good injectability over apatitic cements. To induce the bioactivity of brushite cements, the goal was to convert it into a bone-like low crystalline carbonate apatite. To achieve this induced transformation, potassium and magnesium were used as dopants which were claimed to be effective in the literature. The cements were immersed for 2 periods of time: 1 day and 6 weeks in Tas-Simulated-Body-Fluid (Tas-SBF) due to its excellent biomimetic properties with its adjusted HCO3- and Cl- ionic rates according to human-blood-plasma. 5% of potassium (to calcium sites) seemed to be more effective over magnesium modification. The aim of this study is to define an optimal composition in terms of transforming brushite into apatite.

Abstract: A joint research project was accomplished with the aim to determine the effect of homogenization conditions (temperature, time, cooling rate) on the microstructure and hardness of 6063 alloy billets. Homogenization is crucial for the ability to extrude the piece in low cost, but mainly without defects. Thus, it is of importance to determine the most suitable homogenization conditions (temperature, time, cooling rate) and its effect on both microstructure and hardness of 6063 alloy billets. Furthermore, the size and morphology of the AlFeMnSi intermetallic particles (mean diameter, aspect ratio) and the precipitation behavior of Mg₂Si constituents are examined in detail via optical (OM) and scanning electron microscopy (SEM). The resulting mean diameter and aspect ratio data generated by such measurements using OM and image analysis of the intermetallics, that are relevant to the extent of beta-to-alpha transformation, are statistically processed with “ANOVA”. Differential Scanning Calorimetry (DSC) tests are used to determine the coherency level of the particles that were precipitated during the different cooling rates and to reveal the potential for resolutioning the precipitates during billet preheating. Samples received from the plant are compared to laboratory samples in order to facilitate the process of optimization the thermal treatment and improve extrudability.

Abstract: The article is devoted to the seaside and riverine territories, which are an integral part of urban and rural settlements. The relevance of the research problem is conditioned to a number of problems corresponding to the current moment in these territories including negative consequences as a result of urban development. The main objectives of the research were outlined, in particular the collection of factual data that allow the appropriate monitoring. Special attention is paid to the architectural transformation of coastal areas, identification of principles by which this transformation must be performed. The practical significance of the presented work is that the results of the study can be used in the development of urban planning documents, namely the projects of complex and local reconstruction of coastal areas.

Abstract: As the most widespread applied structure model since Modernism, Dom-ino Structure is rooted deeply in the sub-conscious of many architects, which in some sense constrains their ability to shape it. Transformation strategies for Dom-ino Structure try to change a hard, homogeneous and rigid model into a soft, flexible, and changeable form. By analyzing the inner property of Dom-ino Structure, this article firstly specifies the orientation of probable transformations. Then, after categorizing cases with integrated architectural form and structure, this article describes three ways of transforming of Dom-ino Structure, including material replacement, geomorphing and mechanics remodeling. These three ways are mutually dependent with a prolongable method system for the innovation of architectural and structural form. This research on the transformation of an existing structural model, presented from the architect’s point of view, is based on Morphological perspective. This research could facilitate the integration of architecture and structure, clarify the inner relations between different structural types, improve the weaknesses of existing structure model while expanding the diversity of architecture forms. It also gives a significant picture of how inspiring the process of collaboration between the architect and the engineer can be.

Abstract: Malaysian Trip Generation Manual (MTGM) is an important document to assist transport planners in forecasting the estimated trip attraction and trip production from a land use. The forecast is crucial in estimating trip generation from a proposed development on the existing road network. Therefore, this study is to verify the accuracy of the existing trip generation model published in MTGM for flat/apartment/condominium and low cost housing subcategories. By applying variable transformation, four alternative models were developed. They were the logarithmic model, the inverse model, the linear-logarithmic model and the logarithmic-linear model. Using residual analysis, influential data was identified and taken out for second analysis. Model selection was based on R² value, t-test and Kolmogorov-Smirnov test results. Besides linear model, logarithmic model is also truly representing trip generation model for both subcategories. There is some difference in the trip generation estimation between the study model and the existing model in MTGM. Sensitivity analysis shows the level of sensitivity between study model and existing linear model. One of the implications in using the studied trip generation model is in evaluating level of service of the junction.

Abstract: This paper proposes a design of transformable wheel for enhancing mobility. Mobility evaluation is performed by mechanical theories as stability margin and obstacle overcoming and its calculating methods are used for simulations. A feasibility of suggested transformable wheel is investigated by simulations. The mobility is able to verify by stability margin angle and ability of climbing up an obstacles which is higher than radius of wheel. Simulation results show that suggested transformable wheel can help overcoming a mobility limitation of former designed robot which is with non-transformable wheel.

Abstract: To improve the high resistance and low Breakdown Voltage (BV) of 4H-SiC SBD, the metal annealing process is usually used to to stabilize SBH. We confirmed that post metal annealing after the chip process also stabilizes SBH by the post annealing experiment of applying failure chips (4H-SiC Ti/Al SBD) that have a forward current (I_F) under 1 [A] with high resistance, because of the metal annealing process error. The result of experiments showed that the I_F increment and BV decrement are proportional to the applied temperatures over 450 °C, and the second additional post annealing shows a decrease of I_F and BV. Aluminum and Titanium transformation with post metal annealing made a decrease of SBH, so that the on-resistance is decreased and BV is decreased (in severe cases, the intense post annealing generates Aluminum spiking). From a result of this work, using a suitable post metal annealing, we can improve the I_F of SiC SBD with a high resistance failure from the metal process event.