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To assess the sustainability of waste management scenario with energy recovery, it is necessary to carry out an adequate analysis of all influential criteria. The main problem in the analysis is to determine the indicators that clearly and fully sublimate the most important influential factors. The model for the assessment of the sustainability of waste treatment scenarios based on multi-criteria analysis AHP (analytic hierarchy process) method is developed. The model predicts an increase in the number of indicators, if it found that a selected number of indicators are not sufficient to distinguish between scenarios and new criterion for the selection of indicators: the relevance of the indicator for certain waste treatment. The model is verified in the case study the city of Nis. Four scenarios were selected and examined: business as usual scenario (landfilling of waste) and the other are created as scenarios with energy recovery and recourses preserving: composting organic waste with recycling inorganic waste, incineration of waste and anaerobic digestion of waste. The assessment of the sustainability of waste treatment scenarios was made in several steps. It is found that the best sustainable scenario is composting of organic and recycling of inorganic waste.

Abstract Background The aim of this paper is to reconsider the necessity for the green transition and the key preconditions for the implementation of a circular economy in Western Balkan countries. With the objective of the research in mind, the method of analysis and synthesis was applied to determine (1) regulatory and institutional prerequisites for the green transition; (2) the need for the Western Balkan countries to redefine the model of sustainable economic growth towards the green transition; (3) the development opportunities for recovery defined in the Green Agenda for the Western Balkans; and (4) the possibility of implementing the circular economy in the Western Balkans. Main text The main findings of the research indicate that: (1) the countries of the Western Balkan region, following the example of the EU, should define a national strategic approach to the green transition with an accompanying action plan and regulatory framework; (2) the biggest challenge of the green transition is the reform of the energy sector and the restructuring of the energy-intensive economy; (3) the countries have untapped potential in renewable energy sources and report the improvement of energy efficiency; (4) the circular economy can boost the green transition, because the countries of the region have a five-time lower value of resource productivity than the average of the EU, while the generation of waste (excluding major mineral wastes) per GDP unit is lower compared to the EU; (5) cross-sectoral governance should be more coordinated. Conclusions The green transition might be a development opportunity for the Western Balkans, which should enable sustainable economic growth as well as energy security and environmental protection. However, the implementation of the Green Agenda is not easy, because the region faces the problem of underdeveloped regulatory and institutional capacities that might provide not only the base for long-term planning but also financial resources for the efficient implementation of projects. In addition, it is essential to understand the principles of the Green Agenda and the interaction of all activities that should enable the achievement of defined goals.

The annual production of plastic waste worldwide has doubled in just two decades, with approximately 390 million tonnes of plastic waste now being generated. In this context, the construction industry must move towards the development of new, more sustainable materials made under circular economy criteria. In this work, a physico-mechanical characterisation of gypsum composites with the incorporation of high-density polyethylene (HDPE) waste, replacing 2–4–6–8–10% by volume of the original raw material, has been conducted. The results show how the incorporation of these plastic wastes improves the water resistance of the gypsum material without additions, as well as producing a decrease in thermal conductivity and greater resistance to impact. On the other hand, it has been found that, as the percentage of recycled raw material added increases, the mechanical resistance to bending and compression decreases, leading to fracture due to a lack of cohesion between the matrix and the waste. Nevertheless, in all the cases studied, mechanical strengths higher than those established by the EN 13279-2 standard were obtained. Thus, the results confirm the viability of these secondary raw materials to be used in the development of new products for sustainable building, especially in the design of prefabricated panels for false ceilings.

In this paper, we compare 2015 satellite-derived natural gas (gas) flaring data with the greenhouse gas reduction targets presented by those countries in their nationally determined contributions (NDC) under the United Nations Framework Convention on Climate Change (UNFCCC) Paris Agreement. Converting from flaring to utilization is an attractive option for reducing emissions. The analysis rates the potential role of reduction of gas flaring in meeting country-specific NDC targets. The analysis includes three categories of flaring: upstream in oil and gas production areas, downstream at refineries and transport facilities, and industrial (e.g., coal mines, landfills, water treatment plants, etc.). Upstream flaring dominates with 90.6% of all flaring. Global flaring represents less than 2% of the NDC reduction target. However, most gas flaring is concentrated in a limited set of countries, leaving the possibility that flaring reduction could contribute a sizeable portion of the NDC targets for specific countries. States that could fully meet their NDC targets through gas flaring reductions include: Yemen (240%), Algeria (197%), and Iraq (136%). Countries which could meet a substantial portion of their NDC targets with gas flaring reductions include: Gabon (94%), Algeria (48%), Venezuela (47%), Iran (34%), and Sudan (33%). On the other hand, several countries with large flared gas volumes could only meet a small portion of their NDC targets from gas flaring reductions, including the Russian Federation (2.4%) and the USA (0.1%). These findings may be useful in guiding national level efforts to meet NDC greenhouse gas reduction targets. Keywords: VIIRS, Gas flaring, Nightfire, Nationally determined contributions, UN climate agreement

The main purpose of this paper is to show that if three specific contextual factors are present in a company, it is possible to achieve great performance improvements with a lean and industry 4.0 implementation. In terms of research methods, a case study was carried out of a project to implement digitalization and Lean practices in a cutlery company, which in fact encompassed a project of master’s degree in engineering and industrial management. Thus, the research question is: “It is possible to achieve major improvements in a lean and industry 4.0 implementation if three specific contextual factors are present in the company, namely (i) commitment of top management, (ii) knowledge on digitalization and lean, and (iii) very low Value-Added Ratio?”. Regarding the company project, action-research was adopted, and the project team began by mapping and diagnosing the production processes of the two product families (knives and spoons/forks). High levels of work in process, long throughput times, poor flow planning and control, and high stocks of finished products, quickly stood out in both families. Improvement proposals were developed and implemented, namely: (i) creation of a production scheduling and control system, (ii) improvement of the warehouse stock management system, and (iii) adoption of new routines, management tools, visual management, and kaizen meetings. The results achieved were excellent (e.g., throughput time reduced by 27.6% and productivity increased by 36.5%) and aligned with Sustainable Development Goals SDG 9 and 12. The findings of this study corroborate that exceptional results in the company performance can be achieved through a lean and industry 4.0 intervention, if the three referred contextual factors occur.

Industrial producers face the task of optimizing production process in an attempt to achieve the desired quality such as mechanical properties with the lowest energy consumption. In industrial carbon fiber production, the fibers are processed in bundles containing (batches) several thousand filaments and consequently the energy optimization will be a stochastic process as it involves uncertainty, imprecision or randomness. This paper presents a stochastic optimization model to reduce energy consumption a given range of desired mechanical properties. Several processing condition sets are developed and for each set of conditions, 50 samples of fiber are analyzed for their tensile strength and modulus. The energy consumption during production of the samples is carefully monitored on the processing equipment. Then, five standard distribution functions are examined to determine those which can best describe the distribution of mechanical properties of filaments. To verify the distribution goodness of fit and correlation statistics, the Kolmogorov-Smirnov test is used. In order to estimate the selected distribution (Weibull) parameters, the maximum likelihood, least square and genetic algorithm methods are compared. An array of factors including the sample size, the confidence level, and relative error of estimated parameters are used for evaluating the tensile strength and modulus properties. The energy consumption and N2 gas cost are modeled by Convex Hull method. Finally, in order to optimize the carbon fiber production quality and its energy consumption and total cost, mixed integer linear programming is utilized. The results show that using the stochastic optimization models, we are able to predict the production quality in a given range and minimize the energy consumption of its industrial process.

Abstract Many Korean apartment units use balconies as semi-indoor spaces by installing external windows. These balconies form environmental buffer spaces to improve comfort and reduce cooling and heating costs. However, the balcony spaces of some units have been removed and have been placed in living rooms. The removal of these environmental buffer spaces has caused problems. Significant heat loss through windows is one of the most serious problems; window surface condensation caused by low surface temperatures in the winter makes residents uncomfortable and damages construction materials. Therefore, it is evident that window design requires improvements. This study introduces a double window system with improved thermal performance and ventilation slits to solve the window surface condensation problem in apartment units without balconies. To verify the thermal performance of the proposed system, temperature factors were analyzed by field measurements. The condensation frequencies were also evaluated by temperature factors at an indoor temperature of 25 °C and 55% humidity. Ultimately, the double window system was able to reduce condensation frequency greatly. An examination of the air volume by ventilation slit operational mode found that the case with an open outer window bottom vent and an inner window top ventilation slit, discharged the indoor vapor effectively and increased the dew point of the window's surface.