Vignan University

About: Vignan University is a education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Astaxanthin from Chromochloris zofingiensis: Feasibility analysis

Abstract: Algae-based astaxanthin is a valuable red keto-carotenoid with multiple biofunctions and widely applied in healthy food, cosmetic, and pharmaceutical industry with fast-growing demands in global market. However, the present cost of natural astaxanthin production from microalga Haematococcus pluvialis is still relatively high. The unique green microalga Chromochloris zofingiensis has been regarded as an alternative astaxanthin producer over other microalgae, which are mainly due to its promising capability of fast growing under heterotrophic and mixotrophic conditions for astaxanthin production with other value-added bioactive compounds beyond. This review will provide a full summary in recent advances on biotechnological production of astaxanthin and other valuable metabolites by C. zofingiensis in different systems as well as the benefits and limitations of C. zofingiensis as the astaxanthin producer. Based on the collation of recent literature and patents, we will present the novel strategies of improving the cultivation process and potential metabolic engineering for enhancing astaxanthin biosynthesis in C. zofingiensis. Future prospects of C. zofingiensis-based microalgal biorefinery are also discussed, which will focus on the evaluation of the potential and feasibility of replacing other producers for low-cost astaxanthin production. In conclusion the current reports will demonstrate that C. zofingiensis is a promising alternative producer for the cost-competitive production of natural astaxanthin. New insights into integrated microalgal biorefinery for economically commercial production of astaxanthin in the near future will be present finally.

The growth of lettuce under T5 led lamps in non-circulating hydroponics

Abstract: Lettuce is grown hydroponically by both circulating and non-circulating hydroponics. The present experiment was done under a wooden built cabin, stacking was done under iron racks. 1-liter bottles were covered with the black polythene covers to avoid the algae formation. The commercially available nutrient solution was grown in the first trail. Each rack was fitted with 3 T-5 led lamps equally spaced along the width of the rack. Each bottle was aerated with an air pump. Seeding was done directly in jiffy plugs and supported with net pots. Purified water was used for both nutrient solution and watering the seedlings. Basic N-P-K nutrition was given until seedling was grown and was transplanted when the seedlings obtained 3 leaves. Covered bottles were filled with nutrient solution leaving a 2 cm gap from the top of the bottle. Net cups were inserted with plants, 3cm of the net cups were covered with nutrient solution and the yield was measured. The PH and TDS were maintained an optimal range over the growing period. In the second trial, seeds were directly placed in the sterilized growing medium, lighting was increased by increasing one light in the seedling rack and seedling stage was measured in terms of the health of the seedling.

Nonlinear Face Classification with Modified 2DDTW

Abstract: Facial physical appearance normally have several variations which occurred due to changes in expression, illumination, occlusion, head pose, and aging. In actual, human eyes can able to justify the authenticity of a person by the use of single image per class. In this paper, a new framework is proposed for nonlinear classification of face images with only one training image per class. Histogram Equalization is used for contrast stretching, Gabor wavelets and Kernel 2D PCA is used to extract local and nonlinear features and those are invariant towards orientation a spatial locality. Those features are fused with PCA fusion and then Two Dimensional Dynamic Time Warping is used for the classification of those feature vectors. The constraints Continuity, Monotonicity and bounded properties of DTW will identify the non linear optimal path between two dimensions of feature vectors simultaneously. The proposed method has evaluated on standard bench mark face databases like ORL, Grimace a Yale and yielded better performance such as 91.35%, 98.5% and 97.16% respectively.

Reduction of PAPR in OFDM using Hybrid SLM-Companding for future Wireless Communications

Abstract: The demand for Orthogonal Frequency Division Multiplexing (OFDM) in wireless networks increases due to the advantages like efficient bandwidth utilization and the simple structure of equalizer. High Peak to Average Power Ratio (PAPR) in OFDM signal leads to lowering of efficiency in High Power Amplifier (HPA). Different approaches were proposed in the literature to reduce the PAPR in OFDM. One among them is Companding which reduces Spectral leakage. The second one is Selected Mapping (SLM) which increases the system performance by reducing the Bit Error Rate (BER). Both the methods are used in practice to reduce the PAPR by a considerable amount. Hence in this paper, the combination of both SLM and Companding techniques are considered which is termed as Hybrid method. The nonlinear companding techniques like Rooting Companding Technique (RCT) and Cosine companding (COS) minimize the PAPR to 4.7 dB and 3.5 dB respectively compared to conventional OFDM signal’s PAPR when they are combined with SLM technique. As the results are encouraging, these techniques can be used in future wireless communication systems.

Novel eco-friendly linear gel for oil well recovery through efficient hydrofracturing

Abstract: The linear gel is prepared by treating bio-diesel with various water samples collected from different water bodies. The new biodiesel based linear gel was employed in the recovery of oil wells through hydrofracturing and pilot tests were conducted for the first time. The viscosity of gel was measured at various bottom hole-circulating temperatures and it was found to vary from 32 to zero dial reading in the range of 45oC to 60oC. The gel was observed to break at 45oC and 60oC in 120 min. So the final temperature was selected as 60oC for the application of gel for coal bed methane (CBM) wells. It was observed that higher levels of salinity in water helped in optimum utilization of gel in real-time application.