AMIRKABIR
Year:2005 | Volume:16 | Issue:61-D|Papers Count:8

In this paper, the spectral transmittances of different solutions of different dyes in water are reconstructed by their colorimetric data measured by scanner. Different solutions were prepared and their RGB data were measured by scanner. Then, by using principle component analysis technique, the eigenvectors and eigenvalues of different sets of solutions were calculated, using RGB data and a linear modeling. Finally, the transmission behavior of each solution is predicted by using the basis function and the RGB values of desired solution. Although the results depend on the sampling technique, but very successful reconstructions are observed, totally.

Fruit juices are among heat sensitive foods. Vitamins, proteins and other organic materials present in most fruit juices may be easily decomposed during heat processing. Therefore, evaporators with minimum residence time and maximum efficiency for concentrating fruit juices should be applied. So, tubular type of falling and climbing film evaporators are suitable devices. In the present investigation, certain important factors in concentration of red grape, yellow grape and apple juice from different parts of Iran in a pilot-plant doule effect falling-climbing film evaporator have been studied. Variation of liquid film thickness, heat transfer coefficient, hydrodynamic and thermal properties show that evaporation of the fruit juices takes place in laminar regime and the required concentration and ratio of the product concentration to acidity can be achieved by multiple-stage evaporation.    

In this research the 50/50 cotton/polyester fabric is treated with NaOH 24% w/w in 60, 90°C for 2,5, 10,90 min and some of the physical properties of the treated fabric samples including weight loss, regain, water drop absorbed, strength, elongation pilling whiteness and dye absorbed evaluated. The effect of sodium hydrosulphite as a reducing agent for absorption of oxygen in the processing media was studied. The results show that alkali treatment in 60°C for 10-20 min with NaOH 24% can hydrolyze the polyester fiber surface and also remove the impurities from the cotton fiber. This treatment may improve some of the fabric properties, for example increase in moisture regain, dye ability and decrease the water drop absorbed and pilling by the fabric.        

This paper discussed the effect of the structural geometry on the work of rupture of industrial yarn (braid). In the present work, parameters that have been discussed are: weave angle, the position of the core and weaving density. The results showed that by increasing the weave angle and weaving density, the work of rupture increase. Further more, the work of rupture of braids with central core are more than braids with separated core. By increasing the number of angle in cross-section of braid, the work of rupture decreases.    

Electrochemical Production of Mn02 from pyrolusite has been investigated. In contrast to the conventional method, the reduction of pyrolusite to MnO and then acid leaching of Mn(II) is carried out directly in one step using Fe2+ as a rdducing agent in sulfuric acid medium. This method was named reductive leaching. In order to recover more Mn (H) from the ore, the solid residue of leaching process was ground to increase the surface area of particles and the leaching was repeated the total Mn recovered from both steps have been 98% After leaching the MnSO4 solution was purified by controlling the pH and precititation of ions other than Fe2+ as sulfides. γ-MnO2 was produced by electrolysis of acidic solution of MnSO4 with optimizing experimental condition.    

In this study Critical Pigment Volume Concentration or CPVC is determined via Electrochemical Impedance Spectroscopy or EIS. Zinc Phosphate in different pigmentation level from 3].3% to 62.6% prepared in epoxypolyamide resin and EIS examined on specimens after 45 minutes of immersion. After fitting the EIS results with an electrical model, electrochemical elements including coating capacitance, coating resistance, double layer capacitance and charge transfer resistance were extracted. Also two electrical elements, total impedance at 100 mHz and phase angle at 10kHz are obtained without fitting the EIS results. Obtained results show obvious changes of elements at PVC=52.2%.          

In this Paper, at first Pigment Red 3 was synthesized and then treated chemically. The treated pigment Showed very good dispersibility and dispersion stability in aqueous media surface chemistry and shape of the pigment were affected by chemical treatments. A Sulfonating agent was used to treat the pigment surface. The chemical reaction was taken place between pigment particles and sulfonating agent. The effect of temperature, reaction time, solvent/pigment ratio and acid/pigment ratio were examined on the pigment performance. In this study experimental design was considered by taguchi method. Uv visible Spectroscopy, Scanning electron microscopy, Densiometry, Turbidiometry and measurement of pH were studied in order to identify pigment properties. Finally with regard to results of inherent properties of each sample, optimum samples were selected for use to in water base media. Also according to the results of Analysis of variance, the effect of each independent parameter on studied properties was considered.