Volume 3 Issue 2

1: Abnormality of Air Temperature in the Early Decade over Lalitpur, Nepal


ABSTRACT: The observation of temperature above Lalitpur was studied using the maximum air temperature at 12 PM and minimum air temperature at 3 AM. The data are taken from the Department of Hydrology and Metrology from 2011 to 2020. The observation, plot, and analysis for this work are based on an Excel plot. In addition, observation shows that the maximum air temperature was recorded in 2016 above Lalitpur up to 32.2 oC on April 29 and June 16, 2016). The minimum temperature was recorded up to -2.4 oC on January 9, 2013. The observation of temperature shows the fluctuation, this is because of several factors like clouds, air pollution, aerosol particles, rainfall, fog, seasonal variations, etc.

Keywords: Air Temperature, Lalitpur, Air Pollution, Aerosol Particles, Seasonal Variation

2: Cyclic voltammogram analysis of the 3,3´- (1,4-phenylene) perchlorates


As a consequence of a three-stage synthesis from terephthalic aldehyde, a series of 3,3 '- (1,4-phenylene) perchlorates including methyl, hydrogen, acetyl, bromio, methoxy and nitro groups (R = Br, H, Me). The matching formazans were reacted with formalin in dioxane in the presence of perchloric acid to produce tetrazin ium salts. Formazans were synthesized by reacting terephthalic aldehyde phenylhydrazone with ar ene diazonium tosylates in a DMF/pyridine combination. The use of ar ene diazonium tosylates greatly simplified the separation and purification of formazans. The p henylhydrazone was produced in aqueous dioxane using the usual approach from terephthalic aldehyde and phenylhydrazine/hydrochloric acid. Individual f ormazans and tetrazinium perchlorates were isolated and characterized by elemental analysis, IR, NMR, UV spectroscopy. The electrochemical reduction of tetrazinium perchlorates was investigated using cyclic voltammetry (CV). Thus, all salts in the cathode region have two one-electron reduction peaks, which are connected to the sequential production of a radical cation and a biradical. It was discovered that donor substituents (R: OMe, Me) in the aromatic ring at position 1 accelerate tetrazinium cation reduction, whereas acceptor substituents (R: NO2, COMe,) inhibit this process. On this premise, it was proposed that in the presence of donor substituents in the aromatic ring at position 1, the matching bis-verdazyl radicals should be easily generated. As a result, 3,3'- (1,4-phenylene) perchlorates are possible antecedents of symmetric biradical systems based on verdazyl radicals.

Keywords: Cyclic voltammograms, Chronoamperometric, radical, electron-withdrawing substituent, electrode potential.

3: Particle Swarm Optimization and Genetic Algorithms to Tackle the PAPR Issue for OFDM System


Orthogonal Frequency Division Multiplexing (OFDM) ensured wireless high-speed data transmission. The transmission of modulated symbols uses a huge number of subcarriers, in the OFDM system. Consequently, the OFDM signals have a large dynamic range, or a high output peak power envelope fluctuation or high PAPR. To mitigate the PAPR, in this paper, we implement two algorithms to reduce the out power envelope fluctuation of the OFDM system, namely PSO and GA. Also, the PTS method and PAPR in OFDM systems difficulty are described briefly. We present an OFDM system through the use of conventional PTS based on PSO and GA. The simulation result shows that both evolutionary approaches outperform the conventional PTS OFDM in-terms of reducing the Peak-to-Average-Power-Ratio (PAPR). Furthermore, the performance of the PSO algorithm is found to be better than GA in-terms of its simplicity and the time execution. On the other hand, the GA algorithm obviously outperforms the PSO and the conventional OFDM, in terms of the PAPR reduction.

Keywords: OFDM, PAPR, PTS, GA, PSO.