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.

A Novel Dual Output Schmitt Trigger Using Second Generation Current Controlled Conveyor

Abstract: Schmitt trigger is designed using the single second generation Current Controlled Conveyor. The proposed configuration utilizes single CCCII and only two externally connected resistors and is able to produce dual output square wave signal. The topology has the benefit of having a simple circuit, offering a large bandwidth and improved slew rate. PSPICE simulator using OrCad 16.3 version, 0.35 µm CMOS technology is used to verify the design, hysteresis is determined and compared with the existing methods available in the literature. The proposed configuration is tested using the experimental setup involving CFOA (AD844AN) and OTA (LM13700). The results have been found satisfactory in both simulation and experimental aspect. Montecarlo analysis and worstcase analysis are determined to prove the circuit efficiency in terms of critical parameters such as resistance with a tolerance of 5%. The hysteresis is also determined, that can reduce the effect of noise, able to produce exact square wave at the output. Schmitt trigger circuits find the applications in the field of Biomedical applications, analog signal processing, communication systems, waveform generators, pulse width modulators, multivibrators, flip-flops and in many other amplifier circuits. The basic application of Schmitt trigger is a square wave generator. The proposed topology is the best suited for monolithic IC fabrication.

Sodium hypochlorite-mediated synthesis of 2,5-disubstituted 1,3,4-oxadiazoles from hydrazides and aldehydes

Abstract: A simple and convenient method for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles has been developed. Structurally divergent symmetrical and unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles can be obtained in moderate to high yields via NaOCl-mediated oxidative cyclization of N-acylhydrazones, generated in situ from aliphatic and aromatic hydrazides and aldehydes.

Matrix Hashing with Two Level of Collision Resolution

Abstract: Hashing is a well-known heuristic used for indexing and retrieving items from database as it uses a shorter hashed key, for finding the element, which is more efficient. In Data Structures, we use a hash table for looking up data rapidly. Hash functions enable rapid lookup of tables or databases by detecting duplicated records in a large file. Hash function should be properly designed to avoid collisions. However collisions are inevitable [1]. This paper presents a new and innovative technique for collision resolution based on two-dimensional array. The proposed strategy followed a unique way of evaluating and implementing algorithms to resolve collisions in hash tables. Analytical modelling and software simulations are quantifiable measures for the effectiveness of our algorithm. Efficient implementations that are easily realizable and productive in modern technologies are discussed. The performance benefits are significant and machines with moderate memory and speed specifications are prerequisites.

Prokaryotic Expression, In Vitro Biological Analysis, and In Silico Structural Evaluation of Guinea Pig IL-4.

Abstract: Interleukin-4 is a signature cytokine of T-helper type 2 (Th2) cells that play a major role in shaping immune responses. Its role in highly relevant animal model of tuberculosis (TB) like guinea pig has not been studied till date. In the current study, the guinea pig IL-4 gene was cloned and expressed using a prokaryotic expression vector (pET30 a(+)). This approach yielded a recombinant protein of 19 kDa as confirmed by mass spectrometry analysis and named as recombinant guinea pig (rgp)IL-4 protein. The authenticity of the expression of rgpIL-4 protein was further verified through polyclonal anti-IL4 antiserum raised in rabbits that showed specific and strong binding with the recombinant protein. The biological activity of the rgpIL-4 was ascertained in RAW264.7 cells where LPS-treated nitric oxide (NO) production was found to be suppressed in the presence of this protein. The three-dimensional structure of guinea pig IL-4 was predicted by utilizing the template structure of human interleukin-4, which shared a sequence homology of 58%. The homology modeling result showed clear resemblance of guinea pig IL-4 structure with the human IL-4. Taken together, our study indicates that the newly expressed, biologically active rgpIL-4 protein could provide deeper understanding of the immune responses in guinea pig to different infectious diseases like TB and non-infectious ones.

D-Q axis voltage ripple minimization of vector control drive using Type-2 NFS controller

Abstract: The voltage ripple is reduced by using conventional proportional integral (PI) controllers require additional filter, and also occurs tuning problem with these controllers. Due to the operating point changes in conventional PI controllers get a nonlinearity output. To overcome above problem, this paper presents Type-2 Neuro fuzzy system (T2NFS) to reduce the voltage ripple in the induction motor by using indirect vector control method. The T2NFS controller performance as compared with conventional proportional integral (PI) controller, voltage ripple reduced in the induction motor without any additional filter and tuning problem is eliminated. In this, the current reference values and original values of current are fed to the T2NFS based controllers and the controller is trained based on the obtained values. The performance of induction motor with indirect vector control method by using T2NFS controllers has been simulated at different operation regions and compared results with PI controllers. The results are experimentally verified with d-space 1104.