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.

Replacing aromatic π-system with cycloalkyl in triphenylamine dyes to impact intramolecular charge transfer in dyes pertaining to dye-sensitized solar cells application

Abstract: In this study, five dyes comprising different donor moieties were proposed with a new design approach. In the triphenylamine (TPA) moiety, the lone pair electron on N takes part in resonance with three phenyl rings. As a result, the donating ability of TPA decreases in TPA-based dyes and hence the intramolecular charge transfer (ICT). We have proposed cycloalkyl moieties in place of phenyl moieties to stop the participation in the resonance of the lone pair with the other two phenyl rings so that the available lone pair on N will be pumped towards acceptor to achieve an efficient ICT. All dyes were subjected to density functional theory (DFT) and time-dependent DFT to evaluate their ground and excited-state properties. The projected density of state and natural bond orbital analyses were carried out to confirm the ICT from the donor to the acceptor moiety and also to comprehend the donating ability of the newly proposed donor moieties. The reorganization energy of the dyes was calculated to find out the conformational changes that occurred during photoexcitation. The dyes were attached to (1 0 1) anatase surface of TiO2 to understand the electron transfer from the excited-state of the dye to the conduction band of the TiO2. The adsorption energy of the dyes onto the (1 0 1) anatase surface of the TiO2 was also evaluated. The absence of defect states in the density of states spectrum indicated the smooth electron transfer at the dye/TiO2 interfaces.

Highly Selective and Sensitive Colorimetric and Fluorimetric Sensor for Cu 2

Abstract: A newly designed fluorescent and colorimetric probe was synthesized and selective detection of cu2+ was successful in aqueous medium. The design strategy exhibited strongly fluorescent when binding with cu2+ based on the change in structure between spirocyclic to a non-cyclic form of rhodamine based dye. The UV visible spectra of probe (6GS2) exhibited three absorption peaks at 229, 309 and 530 nm respectively. The emission spectra of fluorescent probe exhibited wavelength at 550 nm. The peak intensity increases during the addition of copper ion to probe through n-π transition. The probe characterized by different techniques like NMR, absorption, emission, mass and test strips methods.

Forecasting risk using auto regressive integrated moving average approach: an evidence from S&P BSE Sensex

Abstract: The primary objective of the paper is to forecast the beta values of companies listed on Sensex, Bombay Stock Exchange (BSE). The BSE Sensex constitutes 30 top most companies listed which are popularly known as blue-chip companies. To reach out the predefined objectives of the research, Auto Regressive Integrated Moving Average method is used to forecast the future risk and returns for 10 years of historical data from April 2007 to March 2017. Validation accomplished by comparison of forecasted and actual beta values for the hold back period of 2 years. Root-Mean-Square-Error and Mean-Absolute-Error both are used for accuracy measurement. The results revealed that out of 30 listed companies in the BSE Sensex, 10 companies’ exhibits high beta values, 12 companies are with moderate and 8 companies are with low beta values. Further, it is to note that Housing Development Finance Corporation (HDFC) exhibits more inconsistency in terms of beta values though the average beta value is lowest among the companies under the study. A mixed trend is found in forecasted beta values of the BSE Sensex. In this analysis, all the p-values are less than the F-stat values except the case of Tata Steel and Wipro. Therefore, the null hypotheses were rejected leaving Tata Steel and Wipro. The values of actual and forecasted values are showing the almost same results with low error percentage. Therefore, it is concluded from the study that the estimation ARIMA could be acceptable, and forecasted beta values are accurate. So far, there are many studies on ARIMA model to forecast the returns of the stocks based on their historical data. But, hardly there are very few studies which attempt to forecast the returns on the basis of their beta values. Certainly, the attempt so made is a novel approach which has linked risk directly with return. On the basis of the present study, authors try to through light on investment decisions by linking it with beta values of respective stocks. Further, the outcomes of the present study undoubtedly useful to academicians, researchers, and policy makers in their respective area of studies.