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: Control theory & CMOS. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Design and Analysis of 1 × 4 Corporate Feed Conformal Microstrip Antenna Array for X-band Spaceborne Synthetic Aperture Radar Applications

Abstract: Synthetic aperture radar (SAR) collects data about distant objects using electromagnetic waves. It has measuring capabilities without requiring physical contact, making it ideal for remote sensing applications. In the last decade, space-based synthetic aperture radars for earth remote sensing have been created that can operate in all weather and day-and-night circumstances. The antenna works as the interface between the outer surface and the internals of the radar, is a vital component of synthetic aperture radar. The new technique is presented for simulating conformal microstrip patch antenna arrays. A single, 1 × 2 and 1 × 4 corporate feed microstrip antenna arrays using inset feeding technique operating at 9.65 GHz is designed. The characteristics of the antenna array are simulated and also examined. It includes reflection coefficient, VSWR, gain and side lobe level. The improved cross-range resolution of spaceborne Synthetic Aperture Radar is aided by the increased bandwidth and gain. The gain achieved improves cross-range coverage while lowering aerodynamic drag. The proposed designs are simulated using electromagnetic software CST Microwave Studio. The performance characteristics of the single conformal microstrip patch antenna, 1 × 2 and 1 × 4 conformal arrays are compared with planar arrays.

Identification and structural characterization of lactose adduct impurities in isosorbide dinitrate and hydralazine hydrochloride tablets by liquid chromatography‐mass spectrometry and nuclear magnetic resonance studies

Abstract: Isosorbide dinitrate and hydralazine hydrochloride tablets are approved for the treatment of heart failure, prolonged hospitalization for heart failure, and enhanced patient-reported functional status. It has been administered orally. Isosorbide dinitrate and hydralazine hydrochloride tablets contained two additional major unknown peaks (Degradation Product 1 and Degradation Product 2) in the stability studies (25°C/60% relative humidity and 40°C/75% relative humidity). These two unknown degradation peaks formed due to the heat (thermal) and humidity stress of hydralazine hydrochloride. Liquid chromatography separated these unknown degradant peaks. Initially, liquid chromatography-mass spectrometry assessed the degradation pathways and mass of two degradants. Afterward, preparative-liquid chromatography isolated the two major unknown degradation impurities formed under heat (thermal) and humidity stress conditions. Further, to confirm the structures, nuclear magnetic resonance spectroscopy evaluated these two degradants. The liquid chromatography-mass spectrometry and nuclear magnetic resonance spectral data confirmed that the two degradation impurities are hydralazine lactosone ring-opened adduct (Degradation Product 1) and s-triazolo [3,4-α] phthalazine (Degradation Product 2).

A Survey of Class Imbalance Problem on Evolving Data Stream

Abstract: Learning from data streams with both online class imbalance and concept drift (OCI-CD) is receiving much attention in today's world. Due to this problem, the performance is affected for the current models that learn from both stationary as well as non-stationary environments. In the case of non-stationary environments, due to the imbalance, it is hard to spot the concept drift using conventional drift detection methods that aim at tracking the change detection based on the learner's performance. There is limited work on the combined problem from imbalanced evolving streams both from stationary and non-stationary environments. Here the data may be evolved with complete labels or with only limited labels. This chapter's main emphasis is to provide different methods for the purpose of resolving the issue of class imbalance in emerging streams, which involves changing and unchanging environments with supervised and availability of limited labels.

Nutri rich cattle feed (NuCa feed) supplement with improved fiber content free of anti-nutritional factor Phytic acid

Abstract: Most of the commercial ruminant feeds comprise Corn meal, Groundnut cake, Maize etc., which contain anti-nutritional factors called Phytates. They have high binding affinity to cationic minerals. This results in decrease in activity of the cattle by making minerals unavailable for absorption in the intestine. Many of the feed industries add Phytase enzyme that degrades the Phytic acid. Addition of Phytase enzyme is very complex method and increases the cost of the feed. If Phytase is not added, Phytic acid enters the ecosystem through the dung and due to microbial degradation, the Phytic acid gets converted into Phosphates. Phosphate abundance in water bodies leads to Eutrophication, which is a serious ecological issue. And also, in many parts of the country, post-harvest Paddy straw is burnt unused. This intentional stubble burning causes air pollution. We combined paddy straw and Azolla along with jaggery to prepare animal feed supplement. The feed pellets were evaluated for their nutritional composition and efficacy. The efficacy of the developed feed was evaluated by feeding it to milch cows and compared with regular feed for a period of 15 days. The Azolla-Hay feed improved the milk yield and also quality of the milk in comparison to the control group. This study revealed that Azolla in combination with paddy straw powder can be low-cost feed alternative especially during the lean period where the availability of feed is scarce.

LC-PDA-ORD Bioassay of S-(+) and R-(-) Colchicine on Rat Dried Blood Spots: Application to a Pharmacokinetic Study

Abstract: A simple and sensitive normal phase liquid chromatographic method was developed and validated for quantification of Colchicine (COL) enantiomers on rat dried blood spots (DBS). The COL was extracte...