Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Mechanical

This article provides an overview of local pressure coefficients (Cp) on conventional and unconventional tall buildings with the application of CFD. Various modifications in architectural shapes on tall buildings eventually lead to a reduction in the wind load on building surfaces. The surface pressure on conventional (Square and rectangular) buildings is relatively different in comparison to unconventional tall buildings. This study is to assess the surface pressure coefficient over rectangular, taper and setback buildings. The assessed results show that the taper building has 7% Cp rise at ground level (y/H = 0.225) in the windward face, and 34% Cp fall at the middle level (y/H = 0.475) in the side face when compared with the rectangular building. Whereas for the setback building, Cp at ground level near setback (y/H = 0.225) has reduced to about 25% and about 6% at the middle level (y/H = 0.475) in windward than that in the rectangle building. Also, the side faces of the setback showed a 15% drop in Cp than other buildings. In leeward face, Cp is reduced to 56% near setback at the top of the building (y/H = 0.725). This assessment of the Cp on these buildings shows that the effect of setbacks on building reduces the pressure variation on all faces and the downstream wake vortices. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2021.

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School of Mechanical Engineering

Chennai Campus

Lecture Notes in Mechanical Engineering

Assessment of local pressure coefficient over conventional and unconventional tall buildings

This paper presents a complete design and simulation of active suspension actuated using pneumatic air bellow. The electronic controlled active suspension will control all vertical force acting from road surface by regulating the air mass of bellow. Quarter car active suspension is modelled and analysed using Matlab-Simulink. The output of designed active suspension system is simulated under standard road input that gives the response of the suspension to varied roughness of road surface. From the results it is evident that proposed active suspension system can suppress more than 60% than standard passive suspension system. © 2021 Institute of Physics Publishing. All rights reserved.

Fulltext

Journal of Physics: Conference Series

Modelling and control of air bellow based active suspension system

Energy demand in the world is overgrowing due to rising population and technological developments. It is vital to move toward a reliable, economical, and sustainable renewable energy source for energy needs arising in the future. Among other renewable energy sources, solar energy is a promising source of energy for handling long-term problems in the energy crisis. Solar power generation is expanding globally due to high energy demands and decreasing fossil fuel reserves, which are currently the primary sources of power generation. Photovoltaic (PV) cells are employed in the field of solar power generation for the conversion of solar radiation into electricity. Multiple PV cells combine in series or parallel to form a PV module (PVM). They are operated under continually changing environmental conditions causing various faults. Typically, faults are classified into visual, electrical, and miscellaneous faults. These faults should be identified and corrected immediately so that the performance, lifetime, and reliability of PV modules remain unaffected. This paper focuses on the detailed study of the types and causes of various faults that occur in a PVM. Several methods discussed in literature for fault diagnosis of PVM are reviewed. Faults occurring in PVM are particularly highlighted and diagnosis methods to detect and classify faults accurately are elaborated. Recommendations for future research direction are provided based on the reviewed papers. © 2020 Taylor & Francis Group, LLC.

International Journal of Green Energy

Fault diagnosis of visual faults in photovoltaic modules: A Review

Background/Objective: The primary objective of the present study is to distinguish several visual faults which hinder the performance, reliability and lifetime of photovoltaic (PV) modules. Research question: Conventional fault detection techniques require specific operating conditions which also consumed a lot of time, manpower and expenditure. Innovative techniques and technological advancements in the highly paced world expect instant results. Advanced and automatic fault diagnosis is such a process that delivers instant results and guarantees an extended lifetime for numerous critical photovoltaic module (PVM) components. Hypothesis: This study performs an automatic detection of faults in PVM with convolutional neural networks (CNN) that accurately classifies various faults based on the images captured from unmanned aerial vehicles (UAVs). Methodology: Dataset creation is one of the primary constraints when it comes to working with CNN. To overcome this drawback, a data augmentation method is adopted to enlarge the dataset from the limited number of available aerial images of PVM. These augmented images are fed into an automatic fault detection CNN model for deep feature extraction and classification. Results and Conclusion: The presented method exhibits an increase in the accuracy and performance of PVM health monitoring when compared with other conventional solutions. The performances of uniform and non-uniform datasets are also presented. Various pre-trained models like VGG16 and ResNet50 are compared with the proposed solution for performance evaluation. The results demonstrate that the overall classification accuracy of the proposed model for uniform and non-uniform datasets was found to be 95.07% and 94.14% respectively with lesser training time and number of epochs. © 2021 Taylor & Francis Group, LLC.

Energy Sources, Part A: Recovery, Utilization and Environmental Effects

Convolutional Neural Network based Automatic Detection of Visible Faults in a Photovoltaic Module

This study discusses the operation of a Homogeneous Charge Compression Ignition (HCCI) engine using simulated biogas and diethyl ether (DEE) as the primary and secondary fuels respectively. Performance, emission and combustion parameters are measured for various biogas flow rates (8–16 litre/min), composition (50 to 100% methane), intake temperatures (35–80 °C) and loads (20 to 90% of full load). A comparison of injecting DEE at the intake port (port injection) and 7 cm upstream (manifold injection) is also presented. It was demonstrated that at high flow rates and/or with high methane content, biogas can effectively substitute DEE and provide up to 60% of the total energy input. However, the use of lower biogas flow rates and methane fraction resulted in better thermal efficiency (as high as 26%) as well as lower HC emissions. HCCI operation offered simultaneously low NOx (&lt; 0.2 g/kWh) and smoke (~1%). Intake heating ensured better performance and emissions, although it increased the tendency to knock. In general, manifold injection provided superior engine output compared to port injection. The knock limit of HCCI operation could be effectively extended by employing high biogas flow rates and/or methane enrichment. ANOVA study showed that biogas flow rate had a strong influence on most engine output parameters. While methane fraction correlated well with combustion indices, engine torque had a significant effect on thermal efficiency and emissions. © 2021 Elsevier Ltd

Fuel

Effects of operating parameters on the performance, emission and combustion indices of a biogas fuelled HCCI engine

A numerical investigation is performed for heat transfer phenomena occurring in enclosures with different aspect ratios, emissivities and Rayleigh numbers. Interaction of surface radiation and turbulent natural convection of differentially heated enclosures with different positions of heat source and sink has been assessed systematically. The mass, momentum and energy equations have been solved in two-dimensional cartesian coordinates. The turbulence has been modeled using k − ε model. The simulations have been performed on rectangular enclosures with different aspect ratios (0.5, 1, 1.5 and 2) filled with air having Prandtl number 0.7. Surface to Surface radiation model has been incorporated to study the effect of surface radiation on the heat transfer characteristics. The results have been presented in terms of Nusselt number, isotherms and streamlines for various cases. It is concluded that the results can provide insight when designing enclosures for complex engineering applications involving turbulent conditions. © 2021, Indian Academy of Sciences.

Sadhana - Academy Proceedings in Engineering Sciences

Investigations on the interaction of surface radiation and turbulent natural convection in enclosures with multiple positions of source and sink

Introduction: It is important to determine the local forces and moments across the entire cervical spine as dysfunctions such as spondylosis and acceleration-induced injuries are focused on specific levels/segments. The aims of the study were to determine the axial and shear forces and moments at each level under G-x accelerative loading for female and male spines. Methods: A three-dimensional finite element model of the male head-cervical spinal column was developed. G-x impact acceleration was applied using experimental data from whole body human cadaver tests. It was validated with experimental head kinematics. The model was converted to a female model, and the same input was applied. Segmental axial and shear forces and moments were obtained at all levels from C2 to T1 in male and female spines. Results: The time of occurrence of peak axial forces in male and female spines ranged from 37 to 41 ms and 31 to 35 ms. The peak times for the shear forces in male and female spines ranged from 65 to 86 ms and 58 to 78 ms. The peak times for the bending moment ranged from 79 to 91 ms for male and 75 to 83 ms for female spines. Other data are given. Conclusions: All metrics reached their peaks earlier in female than male spines, representing a quicker loading in the female spine. Peak magnitudes were also lower in the female spines. Moments and axial forces varied differently compared to the shear forces in the female spine, suggesting that intersegmental loads vary nonuniformly. Effects of head inertia contributed to the greatest increase in axial force under this impact acceleration vector. Because female spines have a lower biomechanical tolerance to injury, female spines may be more vulnerable to injury under this load vector. © 2021 The Association of Military Surgeons of the United States.

Military Medicine

Neck Vertebral Level-specific Forces and Moments under G-xAccelerative Loading

We report synthesis and characterization of hybrid photoanode made up of Titanium Dioxide (TiO2) and Zinc Oxide (ZnO) nanoparticles prepared by a co-precipitation process. Though TiO2 is the most preferred anode for Dye Sensitized Solar Cell (DSSC), the charge recombination between electrode and electrolyte poses a major challenge. ZnO photoelectrode is a potential alternative due to higher carrier mobility but has a slower electron injection than TiO2. To maximize the benefits of both, a co-precipitation synthesis of TiO2/ZnO is proposed in this work as a promising alternative. The co-precipitation process produces metal oxides TiO2 and ZnO and eventually yields the Anatase TiO2 and Wurtzite ZnO. The experimental investigations of the new co-precipitation process show improved control of particle size, shape, and uniform distribution of ZnO and yet preserve the economy and simplicity of synthesis. The study shows an average crystallite size of 10 nm to 22 nm for TiO2 and 17 nm to 35 nm for ZnO. Wurtzite phase varies from 4.5% to 10.8% in a co-precipitated photoanode. The deconvolution of the typical Photoluminescence (PL) curve shows two distinct bands for ZnO and TiO2 cantered around 390 nm and 460 nm. The study shows that the co-precipitated TiO2/ZnO has a bandgap of less than 3.2 eV, this paves the way for reduced recombination and improved device performance. Further, we fabricated a prototype of a DSSC using photoanode of TiO2/ZnO and a sensitizer of natural plant pigment extracted from Phyllanthus reticulatas and successfully tested the prototype DSSC. © 2020 International Solar Energy Society

Solar Energy

Hybrid photoanode of TiO2-ZnO synthesized by co-precipitation route for dye-sensitized solar cell using phyllanthus reticulatas pigment sensitizer

Electric vehicles (EV's) are very much noise, vibration and harshness (NVH) sensitive due to the absence of engine noise. The outline of this paper is based on vehicle level turning noise evaluation. The impact of the driveshaft angle in the frequency range of 1000-2000Hz. The level of noise while turning at driver and co-driver side is evaluated first. Then the possible countermeasure to address such noise issues are also discussed. The impact on the angular adjusted roller (AAR) joint and driveshaft angle is studied along with the impact on other parameters like powertrain mount stiffness, ground clearance and vehicle architecture. © 2021 SAE International. All Rights Reserved.

SAE Technical Papers

Effect of Driveshaft Angle on Turning Noise in Electric Vehicles and Solution Development Approach

This research emphasizes the impact of Cerium oxide on grain size and corrosion behavior of AA2219 fabricated by the Squeeze casting technique. The composites were effectively characterized by electron backscatter diffraction EBSD, which indicates a significant reduction in grain size inherited by the thermo-physical properties of the dispersoids, which in turn enhances the mechanical properties. The Corrosion behavior of squeeze cast samples was examined through the potentiodynamic polarization technique with Tafel polarization using a standard solution of 3.5% NaCl. The microscopic characterization of the corroded regions reveals that the sample with higher reinforcement of 2% CeO2 is more resistant to the pitting attack due to the hydrophobic nature of the dispersoids. © 2021 Elsevier B.V.