IOSR-JAP   Volume-14 ~ Issue-4 ~ Jul. – Aug. 2022

ABSTRACT: Polypyrrole (PPy) nano composites were synthesized by in situ polymerization technique and characterized by Fourier transform infrared spectra (FTIR), Field Emission Gun Scanning Electron Microscopy (FEG-SEM). The synthesized materials were further used for sensing of NH3 gas. The change in resistance of the material with time was recorded after the response of NH3 gas. The increase in electrical resistance is due to transfer of charge from the sensing material to the analyzed gas and absorption of gas into the polymer matrix. The sensitivity was found maximum for NH3. The PPy nano composite showed maximum sensitivity (48 %) for 400 ppm of NH3 gas.

Keywords: Conductive polymer, NH3 gas sensor, Time response

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ABSTRACT: A black hole is a region of space-time exhibiting such strong gravitational effects that nothing not even particles and electromagnetic radiation such as light can escape from inside it. In many ways a black hole acts like an ideal black body, as it reflects no light. Black holes of stellar masses are expected to form when the massive stars collapse at the end of their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars merging with other black holes, supermassive black holes of millions of solar masses may form There is general consensus that super massive black holes exist in the centre of most galaxies.

Keywords: Black holes, massive stars,galaxy, gravitational effects, light waves

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ABSTRACT: The background radiation level of a zone refers to the total radiation from multiple sources at a certain location on the earth's surface. The energy that moves in the form of electromagnetic waves or particles is referred to as radiation. Among the several radiations: Humans are exposed to ionizing radiation, which can be harmful to their health. We were interested in high-energy radiations that could ionize matter in this work. Overexposure to ionizing radiations can cause a variety of malignancies. Radiation can come from a variety of sources, including cosmic rays (radiation from space), radiation from radioactive atoms on the earth's surface, radiation from our own bodies, and so on. 40K, 226Ra......

Keywords: Background Radiation, GM counter, Longitude, Latitude etc.

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ABSTRACT: Perovskite solar cells (PSCs) are the newestinvestigationfield among variousmodern photovoltaic devices because of their incredibly high conversion efficiency (PCE). The PSC incorporates an ABX3 crystal structure known as perovskite structure as an active light-harvesting layer. Unlike silicon solar cells, PSCs are cheaperand also may bemanufactured using aneasy wet chemical procedure. Various investigations are currently underwayto enhancePSC's PCE to the limits of Shockley-Queisser. In addition, instability and short lifespan are other gravedangers to the PSC's commercialization. This review describes the material structure of perovskite, its applications, the properties of the best solar absorbers, the evolution of PSCs, the structure and mechanism of PSCs, challenges, and future prospects.

Key Word: Photovoltaic, Perovskite material, Perovskite solar cell, HTM, PCE

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