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Cut-off operation is widely used in the manufacturing industry and is highly energy-intensive. Prediction of specific energy consumption (SEC) using data-driven models is a promising means to understand, analyze and reduce energy consumption for cut-off grinding. The present article aims to put forth a novel methodology to predict and validate the specific energy consumption for cut-off grinding of oxygen-free copper (OFC–C10100) using supervised machine learning techniques. State-of-the-art experimental setup was designed to perform the abrasive cutting of the material at various cutting conditions. First, energy consumption values were predicted on the bases of input process parameters of feed rate, cutting thickness, and cutting tool type using the three supervised learning techniques of Gaussian process regression, regression trees, and artificial neural network (ANN). Among the three algorithms, Gaussian process regression performance was found to be superior, with minimum errors during validation and testing. The predicted values of energy consumption were then exploited to evaluate the specific energy consumption (SEC), which turned out to be highly accurate, with a correlation coefficient of 0.98. The relationship of the predicted specific energy consumption (SEC) with material removal rate agrees well with the relationship depicted in physical models, which further validates the accuracy of the prediction models., Peer Reviewed, Postprint (published version)

Studying the specific energy during material removal mechanism at micro-scale provides a better understanding of energy transition between different material removal regimes. Modeling of specific energy into components of sliding, plowing and cutting helps to analyze the influence of grain properties process parameters, and mechanical properties on energy transition between different phases of material removal. Present research put forth the comprehensive model of specific energy consumption for abrasive cut off operating based on the individual models of primary and secondary rubbing energies, specific plowing energy and specific cutting energy. Materials of SS201, Inconel 718, Al 1100, Al 7075 and oxygen free copper (OFC– C10100) have been employed while cutting with semi super abrasive cubitron cut off wheel. Model validation on experimental data revealed that triangular shape of cubitron grits significantly influenced the plowing energy and played an important role in energy transition between different material removal regimes. Moreover, cutting conditions and material properties also affected the overall specific energy consumption, dominance of particular specific energy components and machinability of the materials., Peer Reviewed, Postprint (published version)

Heat storage with thermochemical (TC) materials is a promising technology for solar energy storage. In this paper, a solar-driven desiccant evaporative cooling (DEC) system for air-conditioning is proposed, which converts solar heat energy into cooling with built-in daily storage. The system utilises thermochemical heat storage along with the DEC technology in a unique way. Magnesium Chloride (MgCl2·6H2O) has been used, which serves as both a desiccant and a thermochemical heat storage medium. The system has been designed for the subtropical climate of Lahore, Pakistan, for a bedroom with 8 h of cooling requirements during the night. MATLAB has been employed for modelling the system. The simulation results show that 57 kg of magnesium chloride is sufficient to meet 98.8% of cooling demand for the entire month of July at an elevated cooling requirement. It was found that the cooling output of the system increased with increasing heat exchanger effectiveness. The heat exchangers’ effectiveness was increased from 0.7 to 0.8, with the solar fraction increased from 70.4% to 82.44%. The cooled air supplied to the building meets the fresh air requirements for proper ventilation.

The aim of this research is to provide an in-depth understanding of energy consumption in abrasive disc cutting processes. The specific energy consumed in cutting is measured,analysed, and then characterised in to three components. To this end, an experimental device is built using an Arduino-controlled grinder to measure the specific energy consumed by cutting at different feed rates. Using a model, the experimental data is validated and the Specific Energy Consumed is separated into three energy components: sliding, ploughing and specific cutting energy. Furthermore, the influence of cutting conditions and material properties significantly influenced the specific energy consumption and its components. To analyse the effect of grain shape and the relative dependence of the different components of the Specific Energy Consumed as a function of material removal rate, integral models of specific ploughing energy, specific sliding energy and specific cutting energy are developed. Conventional and super abrasive cubitron abrasive grains were used. Cutting with pyramidal abrasive discs (cubitron) was used for the determination of the relative components of the specific energy consumed. It was found that the specific ploughing energy is more sensitive to the change in material removal rate compared to the sliding energy. Due to the fast shearing and precisely shaped cubitron grains, the transition from sliding to a specific shear regime was so fast for some materials that the magnitude of the ploughing energy was found to be negligible.However, the model implementation for some materials showed that the absence or presence of ploughing energy also depends on the rate of material removed. Finally, the development of a cutting grain model is presented which will allow the study of the chip compression ratio which is not possible to characterise by means of a single cutting grain in metal cutting with thin abrasive discs. This latest development is the beginning of a study of, El objetivo de esta investigación es proporcionar un conocimiento profundo sobre el consumo de energía en los procesos de corte con discos abrasivos. Se mide y analiza la energía específica consumida en el corte, caracterizando dicha energía en tres componentes. Para ello se construye un dispositivo experimental que utiliza una amoladora controlada por un Arduino, para medir la energía específica consumida por el corte a diferentes velocidades de alimentación. Utilizando un modelo, se validaron los datos experimentales y se separa la Energía Específica Consumida en tres componentes energéticos: deslizamiento, arado y energía de corte específica. Además, la influencia de las condiciones de corte y las propiedades del material influyeron significativamente en el consumo de energía específico y sus componentes. Para analizar el efecto de la forma del grano y la dependencia relativa de las diferentes componentes de la Energía Específica Consumida en función de la tasa de remoción de material. Se desarrollan modelos integrales de energía de arado específica, energía de deslizamiento específica y energía de corte específica. Se utilizaron granos abrasivos convencionales y súper abrasivos de Cubitrón. El corte con discos abrasivos de granos piramidales (cubitron) se utilizaron para la determinación de las componentes relativas de la energía específica consumida. Se encontró que la energía de arado específica es más sensible al cambio en la tasa de remoción de material en comparación con la energía de deslizamiento. Debido a los granos de Cubitrón de corte rápido y de forma precisa, la transición de deslizamiento a un régimen de corte específico fue tan rápida para algunos materiales que la magnitud de la energía de arado resultó ser insignificante. Sin embargo, la implementación del modelo para algunos materiales demostró que la ausencia o presencia de energía de arado también depende de la tasa de material removido. Por último se presenta el desarrollo de un modelo de gra, Postprint (published version)

Specific energy consumption is an important indicator for a better understanding of the machinability of materials. The present study aims to estimate the specific energy consumption for abrasive metal cutting with ultra-thin discs at comparatively low and medium feed rates. Using an experimental technique, the cutting power was measured at four predefined feed rates for S235JR, intermetallic Fe-Al(40%), and C45K with different thermal treatments. The variation in the specific energy consumption with the material removal rate was analyzed through an empirical model, which enabled us to distinguish three phenomena of energy dissipation during material removal. The thermal treatment and mechanical properties of materials have a significant impact on the energy consumption pattern, its corresponding components, and cutting power. Ductile materials consume more specific cutting energy than brittle materials. The specific cutting energy is the minimum energy required to remove the material, and plowing energy is found to be the most significant phenomenon of energy dissipation., Peer Reviewed, Postprint (published version)

Electronic waste (E-waste) is becoming most rapidly expanding solid waste stream of the world. Pakistan receives thousands of tons of E-waste from developed countries like the USA and Europe. At present, quantification of E-waste imported to Pakistan and materials recovered from such waste is not well defined. Therefore, the objectives of this research include estimation of E-waste flow and assessment of potential quantities of recyclable metallic and non-metallic components. As a result, it was found that, on average, 95,415 tons of E-waste is imported into Pakistan annually. It contains a variety of metals such as gold, silver, copper and non-metals like plastics and glass as well as hazardous materials. It was also found out that all the recycling activity takes place in informal sectors without any consideration to environmental pollution and safety of workers. Improvements in the existing legal framework regarding import and recycling of E-waste have been proposed. These proposals include take back, prohibition of illegal import and good environmental management., QC 20170703

This paper presents the analysis of installing the vertical axis wind turbines between the building passages on an island in Stockholm, Sweden. Based on the idea of wind speed amplification due to the venture effect in passages, practical measurements were carried out to study the wind profile for a range of passage widths in parallel building passages. Highest increment in wind speed was observed in building passages located on the periphery of sland as wind enters from free field. Wind mapping was performed in the island to choose the most favourable location to install the vertical axis wind turbines (VAWT). Using the annual wind speed data for location and measured amplification factor, energy potential of the street was calculated. This analysis verified that small vertical axis wind turbines can be installed in the passage centre line provided that enough space is provided for traffic and passengers., QC 20170825