Intelligent systems for volumetric feature recognition from CAD mesh models

This paper presents an intelligent technique to recognise the volumetric features from CAD mesh models based on hybrid mesh segmentation. The hybrid approach is an intelligent blending of facet-based, vertex based, rule-based, and artificial neural network (ANN)-based techniques. Comparing with existing state-of-the-art approaches, the proposed approach does not depend on attributes like curvature, minimum feature dimension, number of clusters, number of cutting planes, the orientation of model and thickness of the slice to extract volumetric features. ANN-based intelligent threshold prediction makes hybrid mesh segmentation automatic. The proposed technique automatically extracts volumetric features like blends and intersecting holes along with their geometric parameters. The proposed approach has been extensively tested on various benchmark test cases. The proposed approach outperforms the existing techniques favourably and found to be robust and consistent with coverage of more than 95% in addressing volumetric features

Natural sensitizers-mesoporous TiO2 hybrid nanomaterial for future optoelectronic applications

AbstractOptoelectronics deals with the design and development of electronic devices including photodetector (PD), solar cells and LEDs for light detection, generation and application for a variety of purposes. It includes X-rays, Gamma rays, Infrared, Ultraviolet and Visible light. In the current work, we developed a self-powered and efficient UV–Visible PD by sensitizing mesoporous TiO2 powder with a natural sensitizer Ficus Benghalensis (Banyan) and Rubia Cordifolia (Manjishtha). Prominent enhancement of visible light absorption was noted due to sensitizers as compared to pure TiO2 with the decrease in band gap from 3.13 eV to 3.01 eV. TiO2 photoanodes fabricated with and without dye loading were characterized using XRD, FESEM and UV–Visible and FTIR spectroscopy and used to fabricate a PD device with an active area of 0. 25 cm2. At zero bias, the Banyan-loaded TiO2 PD (B-TiO2) demonstrates enhanced photo response by nearly three times than Manjishtha-loaded PD (M-TiO2). At zero bias voltage, the PD (B-TiO2) displayed very high photosensitivity (8665), Dark current density (126 nA), Photocurrent density (158 µA), Photoresponsivity (1.88 mA/W), Rise time (0.31S) and Decay time (0.35S), respectively. Therefore, the use of novel dye for electricity generation in this study opens new routes to design future optoelectronics devices

Design of passive suspension system to mimic fuzzy logic control active suspension system

Background: This paper proposes a method for designing a passive suspension system that determines the optimal suspension settings while offering feasible performance near an active suspension system. A mathematical model of a nonlinear quarter car is developed and simulated for control and optimization in MATLAB/Simulink® environment. The input road condition is a Class C Road, and the vehicle moves at 80 kmph. Fuzzy logic control (FLC) action is used to accomplish active suspension system control. An approach for investigating optimal suspension settings based on the FLC control force is described here. The optimized passive suspension system is supposed to have the same suspension travel and velocity as an active suspension system. The least square technique is implemented to optimize the suspension parameters of the passive suspension system. Results: The initial passive suspension system, FLC active system, and optimized suspension system are simulated in MATLAB/Simulink® environment. It is observed that RMS acceleration for the FLC system is 0.5057 m/s2, which is reduced by 46% (passive suspension system has RMS acceleration of 0.9322 m/s2, which is uncomfortable). For optimized system, RMS acceleration is 0.6990 m/s2. It is observed that the optimized passive suspension system almost mimics the initial FLC active suspension system. For the optimized system, sprung mass acceleration and VDV are improved by 30% and 27%, respectively, compared to the initial passive system. Conclusion: It is observed that the optimized passive suspension system mimics the initial FLC system. Also, an optimized FLC system has improved health criterion-based results compared to other suspension systems

Multi-objective optimization and experimental investigation of quarter car suspension system

The primary function of the suspension system is to improve ride comfort and vehicle control. However, typical passive suspension systems have to do this contradicting task. In order to do this task, one needs to tune/optimize the suspension parameters. This study presents a methodology for determining the optimal suspension settings for a quarter car suspension system. Macpherson strut suspension is used to construct a test rig and simulate a quarter-car suspension system. For ride comfort and optimization purpose, a Macpherson strut model is implemented in Matlab/Simulink® environment. The suspension system is optimized for ride comfort and stability. Frequency-weighted RMS acceleration, vibration dose value (VDV), and maximum transient vibration value (MTVV) objectives are used for ride comfort and for stability RMS suspension deflection and RMS tire deflection are used as objective function during optimization study. As a result, the optimization problem becomes multi-objective type, and the spring stiffness and suspension damping are optimized using the NSGA-II algorithm. Further, the optimized strut is installed and tested on quarter car test rig and further on car to validate the results. The simulation results and test rig results are obtained and validated. From test rig and vehicle results, optimized strut improves ride comfort, by reducing RMS acceleration, VDV and MTVV and provides vehicle stability. The study of optimized strut on vehicle is conducted using four road surfaces and four different drivers. The findings are represented graphically in time as well as frequency domain and also in tabular form

Soft annealing effect on the properties of sputter grown Cu2ZnSnS4 (CZTS) thin films for solar cell applications

In present study, CZTS films were fabricated using 2 different processes and their properties have been compared. The first is a 2-stage process which includes deposition of CZT followed by sulfurization and the second is a 3-stage process which includes deposition of identical CZT, soft annealing (pre-heating) and sulfurization. Structural, morphological, optical and compositional properties of CZTS films are investigated by XRD, Raman spectroscopy, FE-SEM, UV–Visible spectroscopy, EDS and photoresponse measurements. Structural analysis revealed that films prepared by both processes have polycrystalline kesterite-CZTS structure and exhibit prefered orientation along (1 1 2) direction. It has been observed that soft annealing temperature in 3-stage process significantly improve the crystal quality of CZTS films. Surface morphology of films sulfurized at 550 °C shows a uniform and compact micrograin (∼0.31 µm) without cracks. The soft annealing temperature significantly improves micrograin size (∼0.49 µm) and compactness of CZTS films. UV–Visible spectroscopy showed that the band gap of all CZTS films is in optimal range. The CZTS films fabricated by 3-stage process, exhibits high photocurrent response under intermittent visible-light irradiation, implying that they can useful as an absorber layer in solar cells

Soft annealing effect on the properties of sputter grown Cu2ZnSnS4 (CZTS) thin films for solar cell applications

In present study, CZTS films were fabricated using 2 different processes and their properties have been compared. The first is a 2-stage process which includes deposition of CZT followed by sulfurization and the second is a 3-stage process which includes deposition of identical CZT, soft annealing (pre-heating) and sulfurization. Structural, morphological, optical and compositional properties of CZTS films are investigated by XRD, Raman spectroscopy, FE-SEM, UV–Visible spectroscopy, EDS and photoresponse measurements. Structural analysis revealed that films prepared by both processes have polycrystalline kesterite-CZTS structure and exhibit prefered orientation along (1 1 2) direction. It has been observed that soft annealing temperature in 3-stage process significantly improve the crystal quality of CZTS films. Surface morphology of films sulfurized at 550 °C shows a uniform and compact micrograin (∼0.31 µm) without cracks. The soft annealing temperature significantly improves micrograin size (∼0.49 µm) and compactness of CZTS films. UV–Visible spectroscopy showed that the band gap of all CZTS films is in optimal range. The CZTS films fabricated by 3-stage process, exhibits high photocurrent response under intermittent visible-light irradiation, implying that they can useful as an absorber layer in solar cells

Preparation and characterization of γ-In2Se3 thin-film photoanodes for photoelectrochemical water splitting

Indium selenide (γ-In2Se3) films were prepared using RF magnetron sputtering. Influence of deposition time on structural, optical, morphological, and photoelectrochemical (PEC) performance was studied. Formation of γ-In2Se3 is confirmed by low angle XRD, Raman spectroscopy, and XPS analysis. Surface morphology investigated using FE-SEM shows that γ-In2Se3 films are uniform and have a dense grain structure, without cracks and holes. Optical properties show that γ-In2Se3films absorb mainly in the UV region, and the bandgap energy decreases from 2.81 to 2.27 eV as deposition duration increases. Conduction and valance band-edge potential values show that γ-In2Se3 films are suitable for photoelectrochemical hydrogen evolution. PEC activity of γ-In2Se3 photoanodes was evaluated using linear sweep voltammetry (LSV), and there was an increase in photocurrent density with deposition time. Electron impedance spectroscopy (EIS) analysis revealed that γ-In2Se3 photoanodes had high charge transfer resistance, and it decreases with deposition time, which leads to improved PEC performance. Investigation of Mott Schottky's (MS) results shows a shifting of flat band potential towards negative potential, suggesting movement of fermi level towards conduction band edge. Carrier density increases from 3.7 × 1019 cm−3 to 8.9 × 1020 cm−3 and depletion layer width of γ-In2Se3 photoanodes are found in the range of ~ 2.67–9.10 nm. The gradual increase in electron lifetime indicates a decrease in the recombination rate of photo-generated charge carriers. An increase in time-dependent photocurrent density reveals that γ-In2Se3 films have effective electron–hole separation. Our work demonstrates that γ-In2Se3 can be a probable candidate for PEC water splitting and opto-electronic applications

Highly stable and Pb-free bismuth-based perovskites for photodetector applications

Herein, we report the synthesis of highly stable, Pb-free bismuth iodide (BiI3 or BI), stoichiometric methylammonium bismuth iodide [(CH3NH3)3Bi2I9 or MA3Bi2I9 or s-MBI] and non-stoichiometric methylammonium bismuth iodide [(CH3NH3)2BiI5 or MA2BiI5 or Ns-MBI] perovskite thin films for photodetector applications. These films are synthesized at room temperature by a single step solution process spin coating method. The structural, optical, and morphological properties of these films were investigated using different characterization techniques such as XRD, Raman spectroscopy, FE-SEM, UV-Visible spectroscopy, etc. Formation of BI, s-MBI and Ns-MBI thin films is confirmed by XRD and Raman spectroscopy measurements. XRD analysis reveals that BI has a hexagonal crystal structure and a P63/mmc hexagonal space group for s-MBI and Ns-MBI. The optical properties of BI thin films show a high absorption coefficient (∼104 cm−1) and a band gap of ∼1.74 eV. Similarly, s-MBI films have a high absorption coefficient (∼103 cm−1) and an indirect band gap of ∼1.8 eV. Moving from s-MBI to Ns-MBI, the value of absorption coefficient is ∼103 cm−1 and the band gap corresponds to ∼2 eV. Finally, photodetectors based on the synthesized BI, s-MBI and Ns-MBI perovskites have been directly fabricated on FTO substrates. All photodetectors exhibited highly stable photo-switching behaviour along with excellent photoresponsivity and detectivity, with a fast response and recovery time. Our work demonstrates that Pb-free BI, s-MBI and Ns-MBI perovskites have great potential in the future for realizing stable photodetectors

Highly stable and Pb-free bismuth-based perovskites for photodetector applications

Herein, we report the synthesis of highly stable, Pb-free bismuth iodide (BiI3 or BI), stoichiometric methylammonium bismuth iodide [(CH3NH3)3Bi2I9 or MA3Bi2I9 or s-MBI] and non-stoichiometric methylammonium bismuth iodide [(CH3NH3)2BiI5 or MA2BiI5 or Ns-MBI] perovskite thin films for photodetector applications. These films are synthesized at room temperature by a single step solution process spin coating method. The structural, optical, and morphological properties of these films were investigated using different characterization techniques such as XRD, Raman spectroscopy, FE-SEM, UV-Visible spectroscopy, etc. Formation of BI, s-MBI and Ns-MBI thin films is confirmed by XRD and Raman spectroscopy measurements. XRD analysis reveals that BI has a hexagonal crystal structure and a P63/mmc hexagonal space group for s-MBI and Ns-MBI. The optical properties of BI thin films show a high absorption coefficient (∼104 cm−1) and a band gap of ∼1.74 eV. Similarly, s-MBI films have a high absorption coefficient (∼103 cm−1) and an indirect band gap of ∼1.8 eV. Moving from s-MBI to Ns-MBI, the value of absorption coefficient is ∼103 cm−1 and the band gap corresponds to ∼2 eV. Finally, photodetectors based on the synthesized BI, s-MBI and Ns-MBI perovskites have been directly fabricated on FTO substrates. All photodetectors exhibited highly stable photo-switching behaviour along with excellent photoresponsivity and detectivity, with a fast response and recovery time. Our work demonstrates that Pb-free BI, s-MBI and Ns-MBI perovskites have great potential in the future for realizing stable photodetectors