Reaksi Eterifikasi δ-Guaiene Menggunakan Katalis Fecl3/p-tsoh

Δ-guaien merupakan komponen utama kedua dari minyak nilam setelah patchouli alkohol yang dapat diderivatisasi menjadi senyawa eter dengan posisi pada karbon tersier. Senyawa eter pada posisi ini dapat digunakan sebagai zat campuran bahan bakar minyak untuk menaikkan angka oktan. Reaksi eterifikasi dapat dilakukan menggunakan berbagai macam reaksi dengan katalis logam. Penelitian ini fokus pada reaksi katalis logam untuk mensintesis senyawa eter dari δ-guaien sebagai bahan dasar. Reaksi dilakukan menggunakan katalis FeCl3/p-TsOH.H2O dan dianalisa menggunakan FTIR dan KG-SM. Hasil dari FTIR menunjukkan adanya puncak baru pada spectra IR pada 1076 cm-1 yang menunjukkan adanya ikatan C-O eter. Untuk hasil dengan KG-SM, diperoleh senyawa eter sebesar 1,25% dari kromatrogam KG-MS. Persen terbesar dari kromatrogam adalah senyawa alkohol sebesar 88,99%. Dari hasil tersebut dapat disimpulkan bahwa logam efektif digunakan sebagai katalis, namun untuk reaksi eterifikasi katalis seharusnya bebas dari kandungan air untuk mencegah terjadinya produk alkohol

Free-base porphyrins as chemical probes for heavy metal ions detection

Heavy metals are one of the major contaminants in water. They come from various human activities which include mining, smelting, and industrial discharge to name a few. Heavy metals pose a toxic danger to human beings even at their minute concentration. Current methods of detection suffer from numerous limitations such as complicated sample preparation, high cost of instruments, and the need for professional chemists. These challenges make them unsuitable for in situ and real-time monitoring of samples. Fluorescence spectroscopy has emerged as an alternative for sensing applications. They have high sensitivity, good selectivity, and only require small amounts of fluorescent probes. In this study, free base porphyrins were selected as a fluorescent chemical probe to detect the presence of commonly discharge heavy metals - lead (Pb2+) ions and nickel (Ni2+) ions. Solution-based assay and fluorescent measurements were used throughout the study. From the fluorescent analysis, porphyrins showed more selective and sensitivity towards Pb2+ ions. The study also investigated the photostability of porphyrins when porphyrins solutions were put under ambiance light conditions. This solution-based assay fluorescent measurement shows promising potential application of porphyrins to be used as chemical probes on another sensor medium such as on optical fibre and thin film study

5-6 GHz Front End Low Noise Amplifier

This paper presents 5-6 GHz front end Low Noise Amplifier application for IEEE standard 802.11 system for WLAN application. This amplifier uses FHX76LP Low noise SuperHEMT device designed for DBS application from Eudyna Device USA Inc.This paper is present design and simulation of single stage LNA circuits. A single stage LNA has successfully designed with 26.92 dB forward gain and 1.32 dB noise figure, which stable along the UNII frequency band

Stern-Volmer mechanistic study on transition metals embedded onto optical fibre for dissolved oxygen sensing and monitoring: A systematic literature review

Dissolved oxygen (DO) concentration is the most critical parameter to evaluate water quality, commonly addressed in global freshwater, and seawater aquacultures. Research trends and patterns on optical fibre for environmental DO sensing and monitoring, specifically, photonics, are rising and revolutionilising the current practices. Transition metals have emerged as a promising material for use in determining DO concentration in the water. Their unusual physicochemical and optical properties enable them to be used as an oxygen-sensitive dye and a so-called waveguide in thin-film that can be easily integrated with optical fibre. Thus, the selection of transition metals is important in the early phase of this research to design the optical-based transducers for DO sensing and monitoring. The DO concentration needs to be accurately measured in real-time, as its change is a continuous dynamic process. Gaps were identified utilising various transition metals embedded onto optical fibre for the in-situ determination of DO concentration in the water, contributing new knowledge for future scholarly work. The detection mechanism of DO concentration in the water with various transition metals is briefly outlined and concludes by addressing the real world's laboratory-scale challenges. In short, we focus on the Stern-Volmer model for mechanistic study on transition metals for DO sensing and monitoring

Compatible solid polymer electrolyte based on methyl cellulose for energy storage application: structural, electrical, and electrochemical properties

Compatible green polymer electrolytes based on methyl cellulose (MC) were prepared for energy storage electrochemical double-layer capacitor (EDLC) application. X-ray diffraction (XRD) was conducted for structural investigation. The reduction in the intensity of crystalline peaks of MC upon the addition of sodium iodide (NaI) salt discloses the growth of the amorphous area in solid polymer electrolytes (SPEs). Impedance plots show that the uppermost conducting electrolyte had a smaller bulk resistance. The highest attained direct current DC conductivity was 3.01 × 10−3 S/cm for the sample integrated with 50 wt.% of NaI. The dielectric analysis suggests that samples in this study showed non-Debye behavior. The electron transference number was found to be lower than the ion transference number, thus it can be concluded that ions are the primary charge carriers in the MC–NaI system. The addition of a relatively high concentration of salt into the MC matrix changed the ion transfer number from 0.75 to 0.93. From linear sweep voltammetry (LSV), the green polymer electrolyte in this work was actually stable up to 1.7 V. The consequence of the cyclic voltammetry (CV) plot suggests that the nature of charge storage at the electrode–electrolyte interfaces is a non-Faradaic process and specific capacitance is subjective by scan rates. The relatively high capacitance of 94.7 F/g at a sweep rate of 10 mV/s was achieved for EDLC assembly containing a MC–NaI system