ABSTRACT: The concept of the circular economy is gaining momentum in political and business thinking about the transition to a more sustainable future. EuroCommerce and the European Retail Round Table, for example, have argued that leading retailers are keen to play a leading role in shaping the circular economy within Europe. This exploratory research note outlines the characteristic features of the concept of the circular economy, provides some illustrations of how Europe’s leading retailers are publicly addressing circular economy approaches and offers some general reflections on the application of the concept within the retail sector of the economy. The findings reveal that almost 50% of the leading European retailers signalled a commitment to the circular economy and to the principles underpinning it and a number of them looked to evidence their commitment within their retail operations. That said the authors suggest that If Europe’s leading retailers’ public commitments to a more circular economy are to become a reality then they will not only need to effect a radical change in their current business models and that this will need to be accompanied by radical changes in consumers consumption behaviour. More contentiously, there must be concerns that the leading European retailers might effectively capture the concept of the circular economy to justify continuing economic growth.

ABSTRACT: The Step Composite Signals is the combination of vital informative signals that are compressed and coded to produce a predefined test image on a display device. It carries the desired sequence of information from source to destination. This information may be transmitted as digital signal, video information or data signal required as an input for the destination module. For testing of display panels, Composite Test Signals are the most important attribute of test signal transmission system. In the current research paper we present an approach for the noise detection in Composite Step Signal by analysing Composite Step Signal waveforms. The analysis of the signal waveforms reveals that the noise affected components of the signal and subsequently noise reduction process is initiated which targets noisy signal component only. Thus the quality of signal is not compromised during noise reduction process.

ABSTRACT: Compression ignition (CI) engines are most efficient and robust prime movers used in transportation, power generation applications but suffer from the problems of higher level of exhaust smoke and NO_x tailpipe emissions with increased use of fossil fuels. Alternative fuel that replaces diesel and at the same time that result in lower smoke and NO_x emissions is presently needed. Therefore the main aim of this experimental study is to lower the smoke and NO_x emissions and to use non edible oils that replace the diesel. For this locally available honge biodiesel (BHO) and cotton seed biodiesel (BCO) were selected as alternative fuels to power CI engine operated in common rail direct injection (CRDI) mode. In the first part, optimum fuel injection timing (IT) and injection pressure (IP) for maximum engine brake thermal efficiency (BTE) was obtained. In the second part, performance, combustion and emission characteristics of the CRDI engine was studied with two different fuel injectors having 6 and 7 holes each having 0.2 mm orifice diameter. The CRDI engine results obtained were compared with the baseline date reported. The combustion chamber (CC) used for the study was toroidal re-entrant (TRCC). The experimental tests showed that BHO and BCO fuelled CRDI engine showed overall improved performance with 7 hole injector when engine was operated at optimized fuel IT of 10° before top dead centre (bTDC) and IP of 900 bar. The smoke emission reduced by 20% to 26% and NO_x reduced by 16% to 20% in diesel and biodiesel powered CRDI engine as compared to conventional CI mode besides replacing diesel by biodiesel fuel (BDF).

ABSTRACT: Prediction of operating parameters as a function of brake thermal efficiency (BTHE), brake specific fuel consumption (BSFC), carbon monoxide (CO), Hydrocarbons (HC), nitrogen oxide (NO_X) and Smoke opacity is very important in performance and emission characteristics of the engine. In this study, the effect of operating parameters such as load, blend, compression ratio (CR), injection pressure (IP) and injection timing (IT) on the output responses above mentioned were investigated by using ANN (Artificial neural networks) and trained the signal- to- noise ratio (S/N) results obtained from Taguchi L₁₆ orthogonal design. These results are compared with the artificial neural network and confirmation test was conducted and the results obtained were well supported.

ABSTRACT: The time and space distribution characteristics of future high proportion of renewable energy sources will bring unprecedented challenges to the electric power system’s processing and planning, the basic form of electric power system and operating characteristics will have fundamental changes. Based on the research status quo at home and abroad, this paper expounds the four scientific problems of the transmission network planning with high proportion of renewable energy. Respectively, from the network source collaborative planning, transmission network flexible planning. With the distribution network in conjunction with the transmission network planning, transmission planning program comprehensive evaluation and decision-making methods. This paper puts forward the research ideas and framework of transmission network planning considering the high proportion of renewable energy. At the end, the future high proportion of (renewable energy) grid-connected transmission network’s opportunities and challenges are presented.

ABSTRACT: Biomass pyrolysis is a thermo-chemical conversion process that is of both industrial and ecological importance. The efficient chemical transformation of waste biomass to numerous products via pyrolysis reactions depends on process kinetic rates; hence the need for kinetic models to best design and operate the pyrolysis. Also, for an efficient design of an environmentally sustainable pyrolysis process of a specific lignocellulosic waste, a proper understanding of its thermo-kinetic behavior is imperative. Thus, pyrolysis kinetics of castor seed de-oiled cake (Ricinus communis) using thermogravimetric technique was studied. The decomposition of the cake was carried out in a nitrogen atmosphere with a flow rate of 100mL min^-1 from ambient temperature to 900 °C. The results of the thermal profile showed moisture removal and devolatilization stages, and maximum decomposition of the cake occurred at a temperature of 200-400 °C. The kinetic parameters such as apparent activation energy, pre-exponential factor, and order of reaction were determined using Friedman (FD), Kissinger-Akahira-Sunose (KAS), and Flynn-Wall-Ozawa (FWO) kinetic models. The average apparent activation energy values of 124.61, 126.95 and 129.80 kJmol^-1 were calculated from the slopes of the respective models. The apparent activation energy values obtained depends on conversion, which is an evidence of multi-step kinetic process during the pyrolytic decomposition of the cake. The kinetic data would be of immense benefit to model, design and develop a suitable thermo-chemical system for the conversion of waste de-oil cake to energy carrier.

ABSTRACT: Nature is losing the war against capitalism and needs us to come to her defense in a way that may seem counter-intuitive. We, humans, have our ways of doing things and natural processes follow their own courses, often distinctly foreign to our inclinations. Our modern-day business practices are designed for the short term, are self-centered, tending toward precision and inevitably leading to environmental destruction. Natural processes, on the other hand, are intended for the long term, are generous, are highly imprecise and almost always lead to flourishing ecological systems. While humankind produces primarily negative externalities, nature produces almost exclusively positive externalities or no externalities at all. This paper discusses a way that both negative and positive anthropogenic externalities can be used to encourage ‘good consumption’ and to discourage ‘bad consumption’ for the benefit of natural ecological systems, human societies, family units, and our future generations.

ABSTRACT: Silk cotton seed kernel oil is given as a new source for methyl ester synthesis. Crude silk cotton oil was used as feedstock raw materials for methyl ester production using dimethyl carbonate as solvent and KOH catalysis. The maximum methyl esters yield produced as 97% with a kinematic viscosity (4.25 ± 0.2 5 mm²/sec) was reached at 80 °C by boiling a mixture of dimethyl carbonate (DMC) and oil mole ratio as 8:1 with 1.5 wt.% KOH catalyst (oil weight based ) for 75 min. The produced products were analyzed using gas chromatography-mass spectrometry to identify the methyl esters. The properties of the methyl esters from silk cottonseed kernel oil produced met the specifications of ASTM for methyl esters. The kinetics of the KOH-catalyzed transesterification of diglyceride (DG) and triglyceride (TG) with DMC were studied at 40 to 90 °C. We found that the activation energies for transesterification of diglycerides and triglycerides were 89.8 and 83.3 kJ/mol, respectively. The results showed that all the reaction variables studied had beneficial effects.

ABSTRACT: The objective of this paper is to study in which way the strategies to combat climate change, as prescribed in the UN SDG number 13, are influenced by ambiguity aversion. Countries can tailor the UN SDGs to their priorities and situations, but the urgency in their planned actions to combat climate change and its impact is affected by the form of uncertainty surrounding their decisions. Following a Choquet-Brownian process to model ambiguity aversion on the dynamics of environmental damage, we study an international pollution control problem where countries may behave cooperatively or non-cooperatively. We show that carbon emissions decrease, as perceived ambiguity increases, in keeping with the precautionary principle, and such decrease is lower if countries behave non-cooperatively. We also examine the interrelation between the precautionary principle and the effects of a declining social discount rate and increase in population, and find that optimal policies induce more precaution. Our results have important implications for national strategies and actions to combat climate change.

ABSTRACT: The performance of steam power plants, utilizing recovered waste heat from air-fuel and oxy-fuel combustion, are compared. Temperature profiles in the heat recovery steam generator (HRSG), steam production rate, net-work output and energy efficiency are simulated for different conditions. Investigations are made into the effect of varying pinch point on HRSG performance, net-work and energy efficiency for power generation utilizing oxy-fuel combustion. It is found that with increased pinch point there is an associated decrease in HRSG and steam plant efficiencies. Exhaust gas composition influences the energy efficiency of the power plant. When air-fuel and oxy-fuel combustion are compared there is a reduced amount of nitrogen in the oxidant stream in the latter case. When comparing air-fuel and oxy-fuel combustion, a considerable deviation in HRSG and steam power plant performance is exhibited, with oxy-fuel combustion offering benefits in system efficiency and plant output. The exhaust gas composition at the HRSG inlet contributes significantly the performance characteristics of the system. Raising the HRSG inlet temperature also increases power generation and system efficiency. The results provide insights into the use of oxy-fuel combustion for systems utilizing HRSG for power generation while demonstrating the influence of gas composition, pinch point, and exhaust gas temperature on system performance, and suggest that oxy-fuel combustion can help enhance the contribution to sustainable development of some energy systems.

ABSTRACT: Artisanal mining is associated with a number of environmental impacts, including deforestation and land degradation, open pits which pose animal traps and health hazards, and heavy metals contamination of land (water and soil), dust and noise pollution. The study examines the perception of environmental degradation of gold mining sites in eastern Cameroon. Human-environment interaction and distance decay models are the conceptual framework for this study.  This study employed a survey research design through the use of primary data while a purposive sampling technique was utilized. A total of 440 questionnaires were administered to selected households across the localities in the study area. Frequencies, percentages, chart, cross tabulations and chi-square tests were used for the data analysis. In other to achieve the aim of this study, a comparison between the nearby and far away residents were done. The study revealed that mining exploitations have brought about changes in the colour and taste of water in the active mining sites (41.7%). Malaria is the number one type of disease that has caused more damage in the localities (81.6%). Mining activities have successfully enabled children in the active mining sites to abandoned school for mining (75.0%). Inhabitants of unit 1 directly linked the problems facing their economic activities to inadequate arable land for agriculture (33.8%) and inhabitants across the study area correlated the problems facing livestock farming to diseases as a result of mining activities (64.6%). The perceived negative effects of gold mining on different socio-economic variables (such as culture, health, education, economy and livestock) vary significantly depending on the proximity from the mining areas (p<0.05). The study concludes that residents living within and far away from the active mining sites were affected by gold mining activities. However, the most worrisome situation concern people working and living within the active mining sites. Therefore, the study recommends that: companies that are involved in mining activities and the government should embark on development projects such as portable water, schools, hospitals, roads, markets, communications facilities in the affected communities.

ABSTRACT: In the current study, an efficient, reliable and relatively novel analytical method is applied to describe the temperature behavior of an unsteady nanofluid flow containing water as the base fluid and graphene oxide particles as the nanoparticles between moving parallel plates. The first phase of this investigation involves turning the governing equations including partial differential equations (PDE) into ordinary differential equations (ODE) using similarity solution. Subsequently, a system of differential equations is solved applying Akbari-Ganji method (AGM) and reliable functions are obtained for temperature and velocity distributions. The effect of viscous dissipation in the derived equations is considered and comprehensively discussed. In order to examine the accuracy and precision of the current analytical results, the equations are also solved by using appropriate numerical solution. By comparing the results, a proper agreement with low error rate is observed between the analytical and numerical results. Finally, by definition of a viscous dissipation ratio parameter, the amount of heat due to shear stress is calculated for several nanoparticles and Eckert numbers. According to the results, viscous dissipation ratio of titanium oxide nanoparticles is greater than that of the other considered nanoparticles.

ABSTRACT: Charcoal stoves have widespread use among the poorer households and outdoor food vendors in Nigeria. In order to improve the efficiency of charcoal stoves, various researches have tried integrating a thermoelectric module in the charcoal stove. The researches, however did not exploit the performance of the thermoelectric modules at different ambient temperatures. To evaluate the performance of thermoelectric integrated charcoal stoves in the sub-Saharan Africa, a self-powered, forced air induced thermoelectric charcoal stove experiment was carried out at five different ambient temperatures of 36ºC, 33ºC, 32ºC, 30ºC and 29ºC and an average fuel hotbed temperature of 1023.75ºC. The thermoelectric charcoal stove generated a maximum voltage of 5.25V at an ambient temperature of 29ºC. The least maximum voltage was generated at the highest ambient temperature of 36ºC. It was observed that the maximum voltage increased with decreasing ambient temperature, this could be attributed to the ambient air being used to cool the thermoelectric generator. Therefore, it could be said that the performance of a forced draft thermoelectric charcoal stove increases with decrease in ambient temperature.

ABSTRACT: A comparative performance analysis is being carried out on a four cylinder, four stroke cycle, spark ignition engine having displacement volume 1297cc. The cylinder head of original gasoline based engine was modified by drilling holes from upper surfaces of head to individual combustion chamber to convert the engine in a CNG direct injection engine. The CNG port injection (CNG-PI) system and CNG direct injection (CNG-DI) system were incorporated with the single engine.  The engine was retrofitted to run on both CNG-PI and CNG-DI system alternately with common CNG tank and other engine loading and measurement system. The engine was equipped with electrical dynamometer having rheostat type loading. The CNG direct injection system was incorporated with various sensors and engine ECU. The operating parameters can be obtained on computer screen by loading the computer with engine through switch box. The engine was run over the speed range of 1000 rpm to 3000 rpm with incremental speed of 300 rpm. The performance parameters were calculated from observations and recorded for both CNG-PI and CNG-DI system. The experimental investigation exhibits that, the average 7-8% reduction in BSFC while the engine was running with CNG-DI system as compared to that of CNG-PI system. Also the engine produced 8-9% higher brake torque and hence higher brake power. The engine gives 6-7% higher brake thermal efficiency with CNG-DI system as compared to CNG-PI system.