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A state-of-the-art integrated heating and cooling facility is established to conduct accelerated tests on large, vertically-oriented alloy rotors, spinning at high speeds. Accelerated testing for such components is accomplished by imposing a cyclically varying thermal stress field in addition to the existing mechanical stress field to estimate the impact on their creep and fatigue life. The cyclic thermal stresses are generated by repeatedly subjecting a rotor to mechanical loading, through alternate transient heating and cooling processes. These transient heating and cooling cycles are carefully designed to maintain specific temperature gradients in the rotor. Such accelerated testing helps provide an accurate estimate of the expected life of a rotor under actual field operating conditions. Thermal effects seen during cooling of large rotor shafts rotating at high speeds, by forced convection is an important subject area, both in academia and industry. In the present application, this feature gains importance in the development of new rotor-alloy materials for utilization in turbines of modern thermal power plants operating at advanced ultra-supercritical conditions. During the cooling phase of the thermal cycle, cylindrical alloy rotors spinning at high speeds (up to 3000 rpm) are enclosed in a cylindrical cavity and are cooled from high temperatures (∼800 °C) with inert gas, by means of forced convection. There is a need to perform many such cooling cycles to establish alloy material characteristics. The direction of cooling gas flow is neither longitudinal nor transverse to the rotor orientation, making this a unique cooling phenomenon. A comprehensive study is undertaken to predict rotor surface cooling, based on a combination of influencing parameters like gas mass flow, annular dimension, and rotor speeds. It is essential to arrive at the best combination of these parameters for obtaining the desired Rotational Heat Transfer Coefficient (RHTC) data. Mean RHTC for each case gives an insight into rotor cooling rates for this unique cooling disposition. Several simulations have been conducted using Computational Fluid Dynamics (CFD) to obtain temperature profiles along the rotor surface and cross-sections during the cooling period. This is supplemented by experimentation with sufficient instrumentation on these rotors. Establishing accurate correlations from the outputs obtained numerically would lead to considerable savings in terms of fixed costs, experimentation time, energy consumed and human resources deployed. This exercise will support tests on multiple such rotor alloy materials in a shorter time frame, thus speeding up the development of next-generation thermal power plants with the highest order of plant efficiency and reduced emissions.

A unique set of test protocols is developed to evaluate new materials for high-temperature and pressure applications (>700 °C and 310 bar) in next-generation thermal power plants. These protocols employ accelerated testing processes to provide a realistic estimate of a component’s life under actual field operating conditions. A state-of-the-art experimental facility to characterize turbine rotors for advanced ultra-supercritical conditions was commissioned at Bharat Heavy Electricals Limited, India. An alloy rotor mounted inside the test chamber is subjected to cyclic thermal and mechanical stresses at elevated temperatures for a predetermined number of thermal cycles to estimate its creep and fatigue life. Cyclic thermal and mechanical loads are applied by sequentially exposing rotors rotating at high speed to transient heating, steady-state soaking, and transient cooling. These transient heating and cooling processes are carefully designed to achieve specific temperature gradients inside the rotor bulk. The rotor is heated in a vacuum by thermal radiation from heater coils. In contrast, rotor cooling is accomplished by circulating relatively cold nitrogen gas through the chamber. Preliminary findings from accelerated tests are reported here. Two computational fluid dynamics (CFD) models were developed to support the transient heating and cooling experiments. Good agreement is observed between CFD simulations and measurements, validating the approach presented. This facility, established under a clean energy research initiative, plays a vital role in reducing the time and cost involved in finding suitable alloy materials, thus advancing the development of ultra-efficient thermal power plants.

Growth models such as Gibrat’s law and Jovanovic’s theory that examine the relationship between the firms’ growth, age and size have either been tested on data from developed economies or from the manufacturing sectors in developing economies. This study checks the suitability of these models in service sectors in developing economies as service sectors have distinct characteristics and developing economies such as India are heavily dependent on this sector. The current study considers three major service sectors contributing to India’s economy vis-à-vis financial services, information technology and real estate for the period 2002–2005. We observed that during 2002–2005, India’s economy was stable without wide fluctuations in economic performance, such as gross domestic product, unemployment or inflation. These sectors not only had a significant impact on economic growth but also had comprehensive microeconomic data. Our results negate both Gibrat’s law and Jovanovic’s theory. We argue that service sectors which are knowledge-intensive will experience different growth patterns compared to manufacturing sectors. We find a definite and significant relationship between firms’ growth and their size and age. Also, we find concluding evidence that younger firms up to 10 years of age struggle a lot more than older firms in the Indian service sector.JEL: D20, D21, D22, D02

Stringent emission norms being followed throughout the world increases the demand for clean and green fuels. Gaseous fuels like compressed natural gas (CNG), liquefied petroleum gas (LPG) and hydrogen are promising alternatives to conventional diesel and gasoline. The use of hydrogen in the IC engine has gained interest among the researchers as it can be easily produced from water through electrolysis. Electrolysis of water produces stoichiometric mixture of hydrogen and oxygen in the ratio of 2:1. This study investigates the performance and emission characters of introducing hydrogen and HHO gas in the inlet manifold of a compression ignition engine in dual fuel mode. Experiments were conducted at 5 different torque conditions where hydrogen and HHO gases are supplied at the flow rate of 6, 12, 18, 24, 30 and 36 LPM along with air in the inlet manifold. The HHO gas was synthesized using stored hydrogen and oxygen in the ratio of 2:1. The performance and emission characteristics were noted for all the conditions. The introduction of hydrogen and HHO gas has reduced the diesel energy share ratio by 86% and 70% respectively at no torque condition. HC emission was found to be decreased at high torque condition when compared to neat diesel operation. Significant increase in NOx emission was noted with increase in gases substitution and torque. CO2 and smoke emissions showed positively decreasing trend as the gas percentage increases, due to reduction in carbon content of the fuel mixture. The cylinder pressure reduced with increase in the flow rate of gases. Combustion duration increases with increase in flow rate as well as increase in torque. It was noted that Brake Thermal Efficiency (BTE) reduced for all operating conditions except at 6 LPM of HHO gas addition in the combustion chamber.

Petroleum (Hydrocarbon – HC) based fuels are used for powering automotive and local power generation systems. Hydrocarbons on combustion produce gases such as CO2, CO, HC and NOx which affect human health as well as environment. Introduction of Hydrogen in Internal Combustion (IC) engine reduces emission and increases the performance. HHO gas which is produced through electrolysis of water can be used instead of hydrocarbon based fuels as the gas contains both Hydrogen as well as oxygen. Due to the challenges in storing Hydrogen, HHO gas is produced onsite through electrolysis process. This article presents the investigation on producing HHO gas through electrolysis onsite. A numerical calculation was done using empirical formula to predict the production of HHO gas. The electrolyser's performance analysis showed that maximum of 0.75 LPM of HHO gas was produced at 80 °C and by supplying 40 A-h. The numerical calculation showed that at the similar working condition the HHO gas produced was 1.3 LPM. The trend of both experiments and model was same for varying the current and rate of generation of HHO gas. This article also presents the effect of parameters such as concentration of electrolyte solution on potential, effect of time and the effect of temperature on production rate. The energy required and the number of modules or units of HHO gas production for real time engine application has been analysed and reported.

Most of the extant studies on social enterprises have taken a static view of institutional complexity and assumed conflict between social and market logics as given. In this study, by taking a dynamic perspective and examining the conflict between social and professional logics, we examine the process of their hybridization and how institutional complexity evolves as they grow and professionalize. Based on our study of a hospital in India, we find that social enterprises operating in highly professionalized fields pass through phases of hybridization and professionals play a crucial role as carriers of alternative logics to social enterprises.

A CFD-based assessment and validation of the NREL Phase-VI Sequence-S rotor at seven wind speeds presented here. The ability of a three-dimensional, unstructured, unsteady RANS solver in successfully predicting the wind flow interactions with a rotating, twisted and tapered rotor is described. The uRANS equations were coupled with SST κ-ω turbulence model and a correlation-based Gamma-Theta transition model. The simulations were performed in ANSYS CFX using both Single Reference Frame (SRF) and Multiple Reference Frame (MRF) modelling approaches. A good agreement with measurements is observed at six of seven wind speeds when comparing the integral quantities, the spanwise and chordwise distributions. The only exception is the 10 m/s wind speed case, attributed to the onset of a massive leading edge stall around the mid-span region. It is successfully demonstrated here how uRANS-based CFD computations can be effectively employed in the study of wind turbine rotor aerodynamics.

To fulfill fast-growing energy needs, all energy sources should be utilized. Renewable energy is infinite and clean. However, its main disadvantage is that renewable energy sources are intermittent. A Hybrid Renewable Energy System (HRES) is built by integrating several distinct energy sources to deal with this problem. In regards to energy economy, economics, dependability, and flexibility, these hybrid systems can surpass the limits of individual energy producing technologies. The power capacity of HRESs increased from 700 GW to 3100 GW globally over the period 2000–2021. This study aimed to offer and analyze a comprehensive literature review of recently published works by several researchers in the area of HRESs. The HRES contains different Hybrid Energy Systems (HESs), which are categorized into three parts, namely, PV_Other, Wind_Other and PV_Wind_Other. These systems, based on different optimization techniques/software with techno-economic objective functions and constraints, are reviewed in this paper. The optimal sizing, control, and power management strategies of the HRES are elaborately discussed to harness its potential. It has been determined that Metaheuristic (MH) methods and HOMER software are mostly employed in the fields of HRES sizing, control, power management, and optimization. The review provides a critical analysis of the shortcomings of the existing HRES systems, while choosing optimization parameters, and control and power management schemes. Moreover, the study encapsulates the various challenges/barriers in adopting HRESs. Finally, this review highlights possible future opportunities for PV, Wind, and other HESs in the area of control, power management, optimization, and optimal sizing.

The calibration and validation of a low-cost external six-component wind tunnel balance (WTB), designed based on Stewart platform configuration, are reported using four different calibration designs. The balance can be easily customised to measure the aerodynamics loads acting on half-wing and drone models in a wind tunnel. Four calibration designs—central composite design (CCD), Box–Behnken design (BBD), BBD with two active filters and decoupling (BBD-2A), and the modern design of experiments (MDOE)—were thoroughly investigated using different computational and statistical techniques to find the right candidate through analysis of variance (ANOVA). A novel approach employed to find reduced model for each loading component in the four calibration designs is described. Systematic validation of the reduced models is performed by benchmarking them against the standard second-order models. These reduced models will play a vital role during actual calibration and measurements to lower the final uncertainty in the measured force and moment components and reduce the time and cost involved in calibrating a WTB.

The research work is to enhance the classification accuracy of the pulmonary nodules with the limited number of features extracted using Gray level co-occurrence matrix and linear binary pattern. The classification is done using the machine learning algorithm such as artificial neural network (ANN) and the random forest classifier (RF). In present, lung cancer seems to be the most deadly disease in the world which can be detected only after the computerized tomography (i.e., CT scan images of the person). Detecting the infected portion at the early period is the challenging task. Hence, the recent researchers where under the detection of pulmonary nodules to categorize it either as benign nodules which named as non-cancerous or as malignant nodules which are named as cancerous. When associated the results with the recent papers, the accuracy has been improved in classifying the lung nodules.

Brain tumor is a hazardous disease. It has to be treated rightly because the patient cannot survive for even a year. This research work is to design a mechanized system that discerns benign and malignant tumor images and improves the classification accuracy. In this system, histogram equalization is used to raise the intensity of tumor so that it can be detected more precisely. In the projected system, segmentation is performed by k-means clustering and Gaussian mixture model (GMM). Along with them, the authors are extracting the features from discrete wavelet transform (DWT) and feature reduction from principal component analysis (PCA). The classifiers support vector machine (SVM) and artificial neural networks (ANN) are used to classify benign and malignant tumor from brain images.

Today, smart grid, smart water networks, smart monitoring system, high security are infrastructure systems that can connect different parts of the world more than we ever thought through the Internet of things (IoT). A wireless sensor network (WSN) consists of multiple sensor nodes for specific applications. WSNs feature easier deployment and better adaptability of devices. In recent time, gesture detection using RFID tags is one of the most important applications of wireless sensor network. The use of body sensors is one of the most developing and advancing technologies in IoT. In the healthcare system consisting of IoT, the patient is monitored using a collection of multiple, efficient and accurate low-power and lightweight wireless sensor nodes. To illustrate the advancement of IoT in enterprises, this study will review the trending research in the field of IoT.

A 6-year-old biracial (Black and White) boy presented with worsening muscle twitching and stiffness. He had normal birth and development. His family noticed muscle twitching involving his thighs when he was 3 years old. Over the next 3 years, twitching spread to involve shoulders, chest, lower back, arms, and lower legs. The patient would feel muscle twitching underneath his skin and at times, these could be visible. His symptoms were worse with cold exposure. Recently, he started experiencing difficulties with fine motor activities such as writing, holding pencils, tying shoelaces, and buttoning. The patient denied myalgia, weakness, rhabdomyolysis, and paresthesias. Medical history includes well-controlled asthma, allergic rhinitis, right hydrocelectomy, and a small bowel intussusception. Family history was unremarkable. Neurologic examination revealed increased appendicular muscle tone, fasciculations involving upper and lower extremities, anterior chest, and paraspinal muscles, mild difficulty releasing hand grip, nasal dysarthria, and bilateral tight heel cords. Sensory examination, reflexes, and gait including heel and toe walking were normal.

The wakes of two wind turbines located at two different sites in flat terrain, one with neutral and one with unstable atmospheric conditions are described. Measurements with high spatial and temporal resolution are made with an instrumented drone that is equipped with a suite of sensors. These measurements for the first time detail at full-scale Reynolds number conditions and at both unstable and neutral atmospheric conditions, the wind speed and turbulent kinetic energy evolution in near- and far-wakes (up to six-diameters) including their vertical profiles at eleven different locations downstream. The dissipation rate of turbulent kinetic energy – obtained from wave number spectra measured in the inertial sub-range – is also reported for the different atmospheric stability conditions. Comparisons of these measurements to the recently developed wake prediction model highlight how these measurements can support further development of wake models.

Social enterprises face multiple resource mobilization challenges that they have to mitigate to address their dual mission of financial sustainability and social value creation. In this art...

HHO gas, which is obtained by the electrolysis of water, is a promising alternative fuel. This paper presents a review of important features and techniques used for producing HHO gas. Various aspects of the thermodynamics and chemical kinetics of electrolysis reactions are discussed. Design and operating parameters for improving the gas production rate are identified. Widely different hypotheses regarding the structure and composition of HHO gas are compared in depth. The state of the art on the use of HHO gas in Internal Combustion (IC) engines is presented in the latter part of the paper. It is seen that the introduction of HHO gas increases engine torque, power and thermal efficiency, while simultaneously reducing the formation of NOx, CO, HC and CO2. The major challenges in using HHO gas in engines are identified as system complexity, safety, cost and efficiency of electrolysis.