Thin Film Analysis By X Ray Scattering

Over one billion people in the world suffer from some form of disability. Nevertheless, according to the World Health Organization, people with disabilities are particularly vulnerable to deficiencies in services, such as health care, rehabilitation, support, and assistance. In this sense, recent technological developments can mitigate these deficiencies, offering less-expensive assistive systems to meet users’ needs. This paper reviews and summarizes the research efforts toward the development of these kinds of systems, focusing on two social groups: older adults and children with autism.

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Socially Assistive Robots for Older Adults and People with Autism: An Overview

We report the effect of substrate temperature (25–300 °C) on the structural, optical and electrical properties of Cadmium Sulphide (CdS) thin films deposited onto glass substrate by Radio Frequency (RF) magnetron sputtering. The structural, morphological, optical and electrical properties of the films were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), UV–VIS-NIR spectroscopy and Hall Effect measurement respectively. The XRD studies showed that the films were polycrystalline with hexagonal wurtzite structure preferentially oriented along the (0 0 2) plane parallel to the substrate surface. The XRD data analysis further revealed the crystallite size of the nanocrystalline films i.e. 22–24 nm exhibiting the fact that crystallite size increased with increasing the substrate temperature. The FE-SEM images along with energy dispersive spectroscopy (EDS) studies confirmed the homogeneous, compact and pin-hole free surface morphology. The UV–VIS-NIR studies unveiled the optical transmittance in the range of 75–90% after 540 nm of the wavelength of light. The optical band gaps were found to be decreasing from 2.34 eV to 2.26 eV with increasing the substrate temperature. The films were characterized as n-type as evidenced by the Hall Effect measurement. The carrier mobility was found to be increasing gradually from 5.53 to 12.57 cm2/V·s by increasing the substrate temperature from room temperature to 300 °C due to the improvement of crystalline quality and grain size of the films. The results showed good optical and electrical properties of the films deposited at 300 °C which are suitable to use as window layer in thin film based solar cells.

Effect of substrate temperature on the properties of RF sputtered CdS thin films for solar cell applications

Effect of pulse bias voltages on performance of CdTe thin film solar cells prepared by pulsed laser deposition

This paper presents a comprehensive overview study of the DDPMSG (direct driven permanent magnet synchronous generator) for wind energy generation system. Wind turbine controls are provided. The PMSG (permanent magnet synchronous generator) is introduced as construction and model. Configurations of different power converters are presented for use with DDPMSG in wind systems at variable speed operation and maximum power capture. Control techniques for the system are discussed for both machine-side and grid-side in details. Grid integration is provided with focus on how to insure power quality of the system and the performance at disturbances.

A Review of Direct Driven PMSG for Wind Energy Systems

In this work,Â we report the structural and optical properties of CdTe thin films on oxygenated Cadmium Sulfide (CdS:O)/Cadmium sulfide(CdS) bilayer using RF magnetron sputtering for different substrate temperatures ( 150, 200, 250, 300 and 350 Â°C) in Argon ambient. The XRD spectra reveal the polycrystalline nature of all theÂ CdTe thinÂ films with preferentialÂ cubicÂ orientation along (111) direction. Raman Spectra showÂ a dominant peak at 163.5 cm -1 Â and its overtone at 328.7 cm -1 Â which corresponded to the longitudinal optical (LO) phonon of CdTe. The SEM microscopy exhibits the uniform growth of CdTe films onto the entire glass substrate. The optical transmission of the CdTe films begin at the edge of 800 nm wavelength and showed interference fringe in the transmission spectra.Â The thickness of the deposited filmsÂ and the optical constantsÂ were calculated from the fringeÂ pattern. TheÂ thicknesses of the CdTe films are found to be increasing from 2.34 I¼m to 2.82 I¼m with increasing the substrate temperature i.e. fromÂ 150 to 250Â°C. Thereafter,Â theÂ CdTe filmÂ thickness decreased to 2.24 I¼m while the temperature increased further up to 350Â°C. The optical bandgap of the deposited CdTe films follows an increasing trend of 1.46 eV to 152 eV with the increase of substrate temperature 150 to 250Â°C after that the bandgap decrease to 1.50 for 350Â°C. Hence the obtained structural and optical properties suggest that the deposited CdTe films can be used as a suitable absorber layer for the thin film-based solar cells.

https://www.ijrer.com/index.php/ijrer/article/download/10431/pdf

Structural and Optical Properties of RF-Sputtered CdTe Thin Films Grown on CdS:O/CdS Bilayers

The demand of energy is growing rapidly in response of the development of the world. The crucial solution of large amount of energy is to harvest alternative source of energy. Sustainable development can be possible by harvesting solar energy as it is smoke free, clean and environment friendly. For low cost, non-toxic and earth abundant feature, CZTS solar cell is very prominent to generate solar power. During this study, numerical analysis has been done by SCAPS 2802 simulator to examine the performance of CZTS solar cell with Indium Sulphide (InSe) buffer layer. In this research work, the proposed ultra-thin CZTS solar cells showed higher efficiency of 16.30% (FF = 0.584, Jsc = 28.06 mA/cm2 and Voc = 1.00 V). In addition, the cell stability of the proposed cell showed better result.

Design of ultra-thin CZTS solar cells with indium selenide as buffer layer

The fundamental objective of this paper is to describe the design and implementation of a magnetic levitation system using phase lead compensation technique. It also verifies the possibility of implementing a system with equipments available in Bangladesh with nominal expenditure. Magnetic levitation is the phenomenon of suspending an object in space using magnetic force. By overcoming the pull of gravitational force, a maglev system can levitate an object into space using a force actuator and proper controlling methods. The theoretical background of the magnetic levitation is studied from mathematical perspective that leads to deriving the model of the main system and the associated controller. The design is carried out using MATLAB, following Root Locus method, with a primary target of levitating a steel ball of 21.6 g at a distance of 1 cm below the coil tip. The system was practically implemented and tested with actual mass. It is observed that the system has achieved the goal by levitating the object at predetermined distance. Moreover, it has been tested for several other masses and the system was capable of levitating all of them which makes it a robust system.

Design and implementation of a magnetic levitation system using phase lead compensation technique

The August 12, 2021 eruption of Fukutoku-Okanoba, a shallow submarine volcano in the Izu-Bonin arc of Japan, is one of few documented submarine eruptions to make a large aerial plume and floating pumice raft. Relative to past eruptions, this event was well-covered by multiple high resolution satellite remote sensors. Here we use satellite remote sensing to assess the eruption style, rates, and products. We find that the 16 km plume was water-rich. Furthermore, we conclude that the 0.1 km^3 raft and 16 km plume were co-genetic and suggest that pumice clasts were delivered to the raft by tephra jets rather than plume fallout. Finally, this eruption highlights a discrepancy between small erupted volumes and high plume heights that may be common for shallow explosive subaqueous eruptions. 

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Simultaneous creation of a large vapor plume and pumice raft by a shallow submarine eruption

This paper describes the implementation and investigation the functionality of the GE 3.6 MW Wind Turbine model implemented in Matlab® and Simulink® when exposed to a wind-step. The robustness of the Wind Turbine is tested by varying the aerodynamic parameters C p, max and λ opt . It is found that, the implemented model operate as expected in different wind speed regions under different disturbances e.g. wind speed step, grid-fault. However, while simulating in the low-wind speed region, it is found that, the pitch controller does not work according to the expected behavior. The pitch-angle tends to change, although it should not be the case for low-wind speed operation.

Ashoke Kumar Sen Gupta

Papers

Structural and Optical Properties of RF-Sputtered CdTe Thin Films Grown on CdS:O/CdS Bilayers

Design of ultra-thin CZTS solar cells with indium selenide as buffer layer

Design and implementation of a magnetic levitation system using phase lead compensation technique

Simultaneous creation of a large vapor plume and pumice raft by a shallow submarine eruption

Implementation and performance analysis of a multi megawatt variable speed Wind Turbine using Matlab® and Simulink®