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Abstract An overview is given of status of projects for the disposal of radioactive waste in very deep boreholes in crystalline rocks which demonstrates all main pros and cons of this technology. New opportunities offered by drilling long horizontal drillholes in ductile formations can provide the basis for projects that have the potential to overcome many of the disadvantages of deep boreholes. The concept of disposal in horizontal drillholes brings together the technologies of borehole and mined repositories using the advantages of both, and therefore deserves an expert discussion at international level.

This is the first attempt to combine disposed bottle caps and natural fibres into sandwich panels. A full factorial design is performed to identify the effects of the skin type (aluminium or coir fibre reinforced laminates) and bottle cap core packing (cubic and orthotropic) on the mechanical properties of the proposed panels. The coir fibre composite skin provides maximum core shear strength, 29 % higher than the aluminium-based panels, in cubic packing, while the flexural modulus is reduced by 45 %. An interlocking effect between the skin and the core is evidenced when coir fibre composites are used. In addition, the cubic cell packing increases the specific mechanical properties, even though with a higher density. The results highlight a promising association of green components and plastic bottle caps for secondary structural applications.

Sustainable technologies in transport systems have attracted significant research efforts over the last two decades. One area of interest is self-powered devices, which reduce system integration complexity and cost with an undoubtedly great potential for improving adaptability and developing sustainability in railway transport systems. One potential solution is a regenerative suspension system, which enables the suspension movements and dissipated energy to be converted into useful electricity. This paper explores the application of hydraulic–electromagnetic regenerative dampers (HERDs) under realistic railway operating conditions for a high-speed train (HST). A vehicle-track-coupled dynamics model is employed to evaluate the regenerative power potential of an HST suspension over a range of operating conditions. The work considers typical route curvature and track irregularity of a high-speed line and speed profile. It was found that power could be regenerated at a level of up to 5–30 W and 5–45 W per generation unit when fitted to the primary and secondary dampers, respectively. Such power-regeneration levels were adequate to supply a variety of low-power-consumption onboard components such as warning lights and wireless sensors. Further analysis of the carbody loading level also was carried out. The analysis revealed that, in the case of a high-speed journey, poor track geometry, low curvature, and reduced carbody weight increased the quantity of regenerative energy harvested by the HERDs. It was concluded that a suitable HERD design could be achieved that could facilitate the development of a smart railway damper that includes both self-sensing and power-generation functions.

Economic development is mainly dependent on fossil fuels. The massive use of fossil fuels has led to changes in the climate environment, in which the deterioration of air quality has affected people’s daily lives. This paper introduces the green growth level as a control variable to explore the connection between carbon dioxide emissions and the level of economic growth. It uses the EKC algorithm and VEC model to analyze Nanjing city’s data from 1993 to 2018. Given the data availability, the ARIMA algorithm was used to project carbon emissions for 2019–2025. It is found that the EKC curve of Nanjing City shows an N-shape, and the growth of economic level will cause the enhancement of carbon dioxide emissions. Carbon emissions will reach 7,592,140 tons in 2025. At present, we are in an essential stage of transition from N-shape to inverted U-shape, and this paper makes several recommendations based on the findings.

The hardened tool steel AISI O1 has increased strength, hardness, and wear resistance, which affects the complexity of the machining process. AISI O1 has also been classified as difficult to cut material hence optimum cutting parameters are required for the sustainable machining of the alloy. In this work, the effect of feed peer tooth (fz), cutting speed (vc), cutting of depth (ap) on surface roughness (Ra, Rt), cutting force (Fx, Fy), cutting power (Pc), machining cost (Ci), and carbon dioxide (Ene) were investigated during the slot milling process of AISI O1 hardened steel. A regression analysis was carried out on the obtained experimental results and the induction of nonlinear mathematical equations of surface roughness, cutting force, cutting power, and machining cost with a high coefficient of determination (R2 = 90.62–98.74%) were deduced. A sustainability assessment model is obtained for optimal and stable levels of design variables when slot milling AISI O1 tool steel. Stable indicators to ensure personal health and safety of operation, P1 values were set to “1” at a cutting speed of 20 m/min or 43.3 m/min and “2” at a cutting speed of 66.7 m/min or 90 m/min. It is revealed that for eco-benign machining of AISI O1, the optimum parameters of 0.01 mm/tooth, 20 m/min, and 0.1 mm should be adopted for feed rate, cutting speed, and depth of cut respectively.

The energy sector, along with the conditions of the natural and built environment, are significantly affected by the tremendous increase in total energy consumption [...]

The object of research is the process of implementing energy-efficient measures at industrial enterprises. One of the problem is the trend of reduction of investment in the sphere of energy efficiency. It has been established that after several years of growth, global investments in energy efficiency and renewable energy sources began to decline in 2017. According to the International Energy Agency, there is a risk that the trend of investment shrinkage will continue. In the framework of the PINE project in Austria, 20 energy audits were carried out, which resulted in the introduction of measures aimed at energy efficiency. According to the results of the project, the link between investment and implementation of measures on energy efficiency and life cycle and type of enterprises implemented in companies of different industries was analyzed and argued. It is established that about 50 % of the identified energy savings from the implementation of measures is the result of the use of frequency drive drives, elimination of leakage of compressed air or modernization of lighting systems. This allows to develop rational business and policy strategies for enterprises at different stages of the life cycle. In the course of the study, an approach focused on single operations selected in this program has been analyzed, which facilitates the identification of links between energy consumption by production units and technological and organizational factors influencing its consumption. The scientific novelty of the research is expressed in the substantiation of critical strategic barriers in the field of investment in energy-efficient solutions, which allowed proposing rational business strategies and appropriate political support measures to overcome them. Due to the fact that enterprises with the same input and output resources can have a different process cycle, payback periods for the same implemented measures may be different. An analysis of the real experience of energy conservation with the developed business strategies and policies of political support allows it to be effectively disseminated in European countries.