Comparative Analysis of AC and DC Distribution System with Respect to Harmonic Distortion Considering Daily Load Profile

Electrical energy is the most efficient and the cleanest form of energy at the moment that is being transmitted and distributed amongst end-users. From its earlier days, the AC system was preferred as an economical solution for transmission and distribution. However, the development in the power electronics technology and the evolution of highly efficient power electronic converters have established the resurgence of DC power system. Furthermore, the trend is shifting towards DC loads as various energy efficient appliances, such as DC inverter air conditioners, operate on DC nowadays. This further advocates the shift towards the DC power system. This research works is an effort to perform the comparative analysis of AC Distribution System (ACDS) and DC Distribution System (DCDS), with regards to power quality and harmonic distortion in particular. The comparison is performed considering load profile and load variation on daily basis. Simulations are performed in MATLAB. It has been concluded at the end that ACDS is better than DCDS in terms of power quality as total harmonic distortion of the DCDS under the same loading and same load variation during the whole day was significantly higher than that of ACDS.

Production, Characterization and Purification of Xylanase from Aspergillus Species

Fermentation is a fundamental part of microbial biotechnology that aids in the production of value-added products. For an optimum fermentation process a microbial strain must be chosen and refined for required product. Plant biomass has remarkable benefits of producing both products and energy. For comprehensive hydrolysis of lignocellulosic biomass, several enzymatic reactions are implicated. Xylanases are the enzymes that participate in the cleavage of internal β-(1,4)-linked D-xylosyl glycosidic bonds in hetroxylan to produce short xylooligosaccharides. The current study is established to produce xylanase from filamentous fungi Aspergillus niger KIBGE-IB36. The synthesis of xylanase was enhanced by optimizing different medium components and physical parameters. The high production of xylanase was achieved at 30°C and pH 8.0 after 06 days of fermentation period. The high yield of xylanase was achieved with 20.0 gL-1 xylan as carbon source with 5.0 gL-1 of meat extract and peptone as a nitrogen source, respectively. The xylanase was purified using gradient precipitation and gel permeation chromatography (Sepharose CL-6B). To confirm the purity of enzyme, native Page gel and zymography was performed. The approximate molecular weight of purified xylanase was 110 kDa. The kinetic characteristics of purified xylanase showed optimal activity at 50°C with pH 5.0 within 10.0 minutes of reaction time. It was also observed that the purified enzyme showed stability with various metal ions, organic solvents and detergents. However, Hg+2, Co+2, Fe+3 and Sodium dodecyl sulfate have inhibitory effect on xylanase activity. The hydrolysis pattern of purified xylanase showed efficient xylan degrading pattern and produced xylose as an end-product. The relative amino acid composition showed greater amount of aspartic acid and N-terminal sequence of purified xylanase revealed that the enzyme have N-glycosylation properties that make the xylanase more stable and have high catalytic potential. In this study, biotechnological exploitation of xylanase showed remarkable production using agro-industrial wastes and its efficient pre-treatment that produced fermentable sugars. Hence, the results obtained from the current study showed that the purified and synthesized enzyme from Aspergillus niger KIBGE-IB36 have potential to be used in different industrial applications mainly in animal feed, paper and pulp industry and enzymatic pre-treatment of agro-industrial wastes.