International Journal of Engineering

354-359

Authors: B. Farokhi* a , M. Rezaei a , Z. Kiamehr a , S. M. Hosseini b

In this study, polyethersulfone based nanofiltration membranes were modified by air plasma generated through dielectric barrier discharge to increase the membrane hydrophilicity aiming to improve the separation and antifouling characteristics. The effect of plasma time on the physico-chemical and separation properties of membrane was investigated. The PES nanofiltration membranes were fabricated by the solution casting technique associated with phase inversion method. The FTIR spectra showed formation of imine and amine functional groups on the membrane surface. The water contact angle decreased form 58 ° to 31 ° by plasma treatment which produces more hydrophilic surface. SEM and SOM images demonstrated that the surface morphology was changed due to ions collision with membrane surface bombardment. AFM results indicated that membrane roughness was initially enhanced by plasma treatment up to 1 minute, and then decreased again by a further increase of treatment time. Membrane water flux increased from 10.05 (L/m2.h) to 35.17 (L/m2.h) remarkably by plasma treatment up to 1 minute and then decreased again at longer treatment times. An opposite trend was observed for the salt rejection of membranes. The water flux was enhanced ~270% for the modified membrane at 2 min plasma treatment whereas rejection declined less than 18%.

366-372

Authors: P. Narasimha Reddy*, J. Ahmed Naqash

Kashmir is located in a region where winter temperatures are very low. During the winter months, the temperature in Kashmir is often below 0⁰ C. Generally concrete placed in colder regions with the help of insulated forms as well as heaters to protect freshly mixed concrete against freezing. These practices try to incorporate unnecessary carbon and leads to an disagreeable carbon footprint. The aim of this study was to evaluate the placing of concrete in colder temperatures with the help of antifreeze admixtures rather than insulated forms or heaters. The objective of this study was to optimize the proportions of two admixtures (Sodium nitrite, Potassium carbonate) to be used in cold weather concreting. Concrete specimens were tested to evaluate the properties such as Strength and elastic properties. The samples were cast in two phases i.e. in exterior winter conditions and under controlled conditions of -5°C with varying proportions of the admixtures. When compared to mixes without antifreeze admixtures the results showed increase in the strength of the concrete samples with addition of 3% Potassium carbonate as well as 3.5% Sodium nitrite by weight of cement was found to be optimum for the temperature range in consideration.

381-392

Authors: F. Eslami-Chalandar, M. Valinataj*, H. Jazayeri

Reversible logic is one of the new paradigms for power optimization that can be used instead of the current circuits. Moreover, the fault-tolerance capability in the form of error detection or error correction is a vital aspect for current processing systems. In this paper, as the multiplication is an important operation in computing systems, some novel reversible multiplier designs are proposed with the parity-preserving property which will be useful for error detection. At first, two optimal signed serial multipliers are presented based on the Booth’s algorithm and its enhanced version called the K-algorithm, utilizing the new arrangements of reversible gates. Then, another low-cost serial multiplier is proposed based on the conventional Add & Shift method to be utilized in the applications in which unsigned numbers are used. Finally, a new signed parallel multiplier is proposed based on the Baugh-Wooley method that is useful for speed-critical applications. The comparative results showed that the proposed multipliers are much better than the existing designs regarding the main criterions used in reversible logic circuits including quantum cost, gate count, constant inputs, and garbage outputs.