Materials Science Forum Vol. 987

Abstract: The study was done to determine the effect of Tacca starch loading on production of amylolytic enzyme from Ragi Tapai. In this study, Ragi Tapai was used as a starter to produce amylolytic enzyme. The fermentation was done in a solid state fermentation with the presence of Tacca leontopetaloides starch as the carbon source. The analysis of total sugar was conducted using DNS method and amylolytic enzyme was determined using Lowry method. The mixture was fermented and incubated for 24, 48, 72 and 96h. The result revealed that the optimum production of amylase was found at 48 h of incubation with amylase activity of 1.91 U/ml/min and 1.42 mg/ml for total protein. The study shows that increment amount of the Tacca starch in cultivation medium, increase the production of the amylase and total protein content. The highest enzyme activity was obtained at 4% of Tacca starch loading with amylase activity and total protein content of 2.14 U/ml/min and 1.42 mg/ml respectively. The study indicated that growth promoters in Tacca starch capable to enhance the activity of microbial consortium in Ragi Tapai for production of the amylolytic enzyme.

Abstract: Empty fruit bunches fibre (EFB) consisting of 44 % cellulose, 16 % lignin and 35 % hemicelluloses component was treated using microwave-alkali (Mw-A) agitated pre-treatment so as to disrupt the recalcitrant structures in the fibre. Morphology and chemical changes of treated EFB were used as indicators to the effectiveness of Mw-A treatment. The results obtained were compared with conventional pre-treatment process. The morphology of the treated fiber was observed using scanning electron microscope. The reduction in the EFB composition during Mw-A treatment was justified by measuring the total extract cellulose; remaining lignin and hemicellulose, and ash content after the process was performed. Results revealed that Mw-A pre-treatment technique exhibited a more effective removal of lignin and hemicelluloses as compared to the conventional or chemical treatment.

Abstract: In Vietnam, heavy metal removal from aqueous solution has been the subject of great attention in the last few years. There are several methods have been developed to reduce heavy metal pollution problems and adsorption technique has been widely used due to the versatility and effectiveness. Cockles are marine bivalve mollusks, whose shell are discharged as wastes by many marine product manufacturers and restaurants. Cockle shell can be economically used as adsorbent for the wastewater treatment. In this study, acid-activated cockle shell was used as an adsorbent material for divalent cadmium ion removal from waste water. The experiments in this work used batch mode adsorption. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the removal efficiency of cadmium. The input to the model was varied as initial cadmium ion concentration from 600 to 1000 mg/L, contact time from 30 to 90 minutes, adsorbent dosage from 0.5 g/L to 1.5 g/L. Analysis of variance was incorporated to judge the adequacy of the models. The predictions of the model were in good agreement with experimental results and the optimal condition is then estimated from the model. Other properties of obtained materials were also investigated using XRD, BET, TGA, SEM analysis methods. The results show that the simple acid-activated cockle shell can be used as a low cost and effective adsorbent for cadmium ion removal.

Abstract: An investigation of heat transfers in a combustible stockpile whose materials are of variable thermal conductivity is conducted in this article. The stockpile is modeled in rectangular slap and a two-step exothermic chemical reaction responsible for the combustion process is assumed. The reactive slab is also assumed to lose heat to the ambient by radiation. The Runge-Kutta Fehlberg (RKF45) method coupled with the Shooting technique is applied to tackle numerically the nonlinear ordinary differential equation (ODE) governing the problem. The process of heat transfer during combustion is made easy to understand by investigating effects of selected thermo-physical parameters on the system’s temperature. The results show that some thermo-physical parameters accelerate the exothermic chemical reaction and therefore raise the temperature levels, and that others help to reduce heat release rate to lower the temperature profiles. The graphs for the results are plotted and discussed accordingly.

Abstract: The wall thickness of plastic bottle is a major consideration for engineers in designing products with strength. For injection blow molding, the thickness depends on the preform size, and shape of the required product. The polyethylene terephthalate (PET) is injected in a mold with the shape of the preform. A stretch injection blow molding machine is used for processing the preform to the shape of the bottle. This research applied finite-element analysis for the process simulation; started from applying the air pressure inside the heated perform – until the PET expanded to the required bottle shape. While most studies were interested in axis-symmetry shape, this paper concentrated on a bottle with uniform flat wall thickness on four sides of a squared section bottle. Several finite-element models were studied and compared the simulation efficiency. Under the investigated area of ±15 mm x 90 mm, the thickness deviation found to be within 3.573%.

Abstract: The key and most energy-consuming process in obtaining inulin is the extraction process. The effectiveness of technology as a whole depends on this procedure. The present research is devoted to studying statics and kinetics of inulin water extraction from artichoke with the purpose of intensification, optimization and modeling of extraction process. Analysis of technical and patent literature has allowed to reveal the ways of aggregation of inulin extraction, in particular, by influence of ultrasonic oscillations on the object of processing. To study the statics of the extraction process, i.e. equilibrium states of the system of interacting substances with the purpose of determining equilibrium concentrations at different temperatures with the use of ultrasonic radiation, kinetic laws of the process and to select rational operating parameters and extraction process intensification, a series of experiments and experimental data processing were carried out. On the basis of the obtained data the process modeling is carried out and the model of mass transfer while inulin extraction is calculated. After have been analyzed the obtained results, in particular, fields of inulin concentration in Jerusalem artichoke and kinetic curves of extraction, it was concluded that in the process of extraction there are slight gradients of concentrations observed, which cause "soft" extraction modes. Furthermore, ultrasonic treatment application at the frequency of radiation 20-22 kHz reduces the duration of the extraction process and significantly increases specific output of inulin. The equations obtained are necessary not only to determine the duration of extraction and its rational mode parameters, but also to model the extraction process mathematical results. These research results can be used in the field of food science and industry, as well as in the development and design of food equipment.

Abstract: Chromatographic separation is an indispensable and important technology in the manufacturing process of chemical products and biomedicine. It uses the distribution differences of a compound in the stationary phase and mobile phase to achieve the separation of the mixture. It is of great value to study the separation process of substances by simulated moving bed chromatography. By digitally simulating the process of moving bed, we can observe the influence of parameter changes on substance analysis by chromatography, and then find out the law of substance separation, which can provide theoretical basis for scientific research of biopharmaceuticals.

Abstract: The ceramic glaze is a glass layer with an amorphous structure. Crystalline glazes are special glazes used to decorate ceramic products. It is based on the research results, the authors proposed a novel crystalline glaze from titanium frit (denoted by FV090/540) for pottery and ceramics with the heating temperature at 1200°C. The heating temperature for the crystallization of glaze was determined by differential thermal analysis (DTA). This study aimed to synthesis willemite crystals (Zn₂SiO₄) in pottery and ceramics. These crystals were detected and identified using X–ray diffraction (XRD), optical microscope (OM), and scanning electron microscope (SEM). The chemical composition of the samples was analyzed by X-ray fluorescence (XRF). From the results of experiments, the authors carried out decorating on industrial ceramic pottery products using this novel crystalline glaze and adjusted the required technological parameters.

Abstract: Plasma cutting machine widely uses in electrical conductivity industrial according to an accuracy dimension and minimum time consuming. A cutting surface and kerf are keys process parameter to establish process quality by controlling diameter of nozzle and size of electrode. Since kerf shape is crated base on nozzle diameter, while electrode is served plasma arc. This paper presents an investigating nozzle wear based on current ampere and processing time. The controlled variables are a plasma-cutting machine, Hypertherm powermax 45 xp, Bindee control CNC machine and cutting path as whorl specimen of low carbon steel. The current Ampere was handled at 35, 40, 45 A. The processing time was controlled at 1, 2, 3, 4, 5 minutes. The diameters of nozzle were measured using digital microscope. The experiments conducted based on ANOVA to establish the relationship of those parameters. The nozzle wear depended upon the current Ampere and processing time in which a regression equation was presented as a result.

Abstract: This study investigates the microstructure and the solidification behavior of titanium-alloyed gray irons. Thermal analysis technique was used to identify the Temperature of Liquidus Arrest (T_LA), the Temperature of Eutectic Undercooling (T_EU) and the Temperature of the Eutectic Recalescence (T_ER). It was found that the titanium addition promoted the formation of the primary austenite causing the larger difference in T_LA and T_EU. In addition, titanium encouraged the refining of eutectic mixture. The SEM showed the graphite particles were refined with increasing titanium. Fine particles of titanium-containing compound were readily observed throughout the microstructure. The hardness as high as 176 HB was achieved at 0.495%Ti addition.