The overall investigation of devices when it comes to the transformation of heat flux into electrical power, and electrical energy to heat power, significantly involves thermoelectric devices (TEDs). These devices provide the potential to build clean energy using a combination of appropriate materials. It has been recognized that more than 60% of the energy generated worldwide disappears, frequently due to the heat involved (exothermic reactions, friction, combustion, and radiation). Economically feasible TED materials and devices have not been successfully developed for larger-scale industrial use due to their low efficiency, unreliability, and high cost of materials and manufacturing. In this study, simple and inexpensive materials and methods were used to tailor the properties of thermoelectric materials to improve their figure of merit, which may be of great potential for meeting future energy demand. Stoichiometric bismuth telluride (Bi₂Te₃) powder was compounded with numerous concentrations of sodium chloride (NaCl) salt particles ranging from 0 to 50% by volume. The NaCl was ground to microscale particles, and cylindrical pellets were crafted using cold pressing and sintering operations. Consequently, the NaCl was leached separately within the samples using hot water, which caused porous structures. Testing equipment was designed to measure the three essential parameters of TEDs—electrical conductivity, Seebeck coefficient, and thermal conductivity—before and after the NaCl leaching process. Following that, the figure of merit was also calculated for each concentration. Primarily porous structures containing 20% NaCl had a 37.55% higher figure-of-merit value compared to the base samples (0% NaCl), and an increase of 89.07% in the figure of merit from the solids content of the samples was observed with NaCl inclusions at a concentration of 30% by volume. The existence of both NaCl and pores was sufficient to increase the figure of merit. Inclusions and porosity detrimentally influenced the electrical conductivity, but there was a substantial rise in the Seebeck coefficient and thermal conductivity changes leading to an increase in the figure of merit. The figure of merit obtained from this study is relatively moderate for the latest generation of thermoelectric materials. However, the materials and methods used here were simple, economical, and scalable and have great potential for use with optimized thermoelectric materials in hopes of further improvement in the figure of merit.

Industry accounts for about 30% of the final energy demand in Germany. Of this, 75% is used to provide heat, but a considerable proportion of the heat is unused. A recent bottom-up estimate shows that up to 13% of the fuel consumption of industry is lost as excess heat in exhaust gases. However, this estimate only quantifies a theoretical potential, as it does not consider the technical aspects of usability. In this paper, we also estimate the excess heat potentials of industry using a bottom-up method. Compared to previous estimates, however, we go one step further by including the corrosiveness of the exhaust gases and thus an important aspect of the technical usability of the excess heat contained in them. We use the emission declarations for about 300 production sites in Baden-Württemberg as a data basis for our calculations. For these sites, we calculate a theoretical excess heat potential of 2.2 TWh, which corresponds to 12% of the fuel consumption at these sites. We then analyse how much this theoretical potential is reduced if we assume that the energy content of sulphur-containing exhaust gases is only used up to the sulphuric acid dew point in order to prevent corrosion. Our results show that 40% of the analysed excess heat potential is corrosive, which reduces the usable potential to 1.3 TWh or 7% of fuel consumption. In principle, it is possible to use the energy of the excess heat from sulphur-containing exhaust gases even below the dew point, but this is likely to involve higher costs. This therefore represents an obstacle to the full utilisation of the available excess heat. Our analysis shows that considering corrosion is important when estimating industrial excess heat potentials.

Ag–Fe co-doped TiO₂ photocatalysts were synthesized by sol–gel method followed by calcination and characterized using X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller, UV–Vis spectroscopy, transmission electron microscopy (TEM) and energy-dispersive X-ray analysis. Photocatalytic activity of these photocatalysts was compared with undoped TiO₂ and Fe-doped TiO₂ for the degradation of synthetic wastewater prepared from diflourotriazoleacetophenone (DFTA) (initial concentration of 8 g/L with initial COD of 75,000 mg/L). The nanoparticles were engineered by varying the catalyst composition (Ti/Ag molar ratio 10–55) for efficient photocatalytic degradation of DFTA. Factors affecting degradation such as catalyst dosage (1–8 g/L), adsorption time in dark (15–60 min) and pH (2–8) were studied to determine optimum conditions for wastewater treatment. The catalyst composition with Fe content of 0.5 wt% and Ti-to-Ag molar ratio of 30, catalyst dosage of 3 g/L, pH 5, adsorption time in dark of 30 min and solar radiation time of 5 h were found to be the optimum conditions for the efficient photocatalytic degradation of DFTA.

This article proposes a new definition of the circular economy following analysis and comparison of the most prominent concepts of the biosphere: Sraffa’s value theory and Moore’s dialectical method. Our paper helps to identify the positions of each of these concepts with regard to free disposal, waste treatment and surplus distribution value. Thus, we are able to show that the mechanisms of the circular economy function simultaneously as part of the appropriation system and as part of the system for the protection of nature. This study enriches the literature on the circular economy by providing analysis of various scenarios of waste disposal. Finally, areas of application and policy implications of the small wins theory are explored in order to guide future research on the circular economy.

This study evaluates an existing non-potable water system serving outdoor services for a medical facility case study (MFCS) in Abu Dhabi (AD), United Arab Emirates, using mixed methods research to identify water demand and availability of non-potable water, and to optimize water reuse for reducing waste, energy consumption and greenhouse gas emissions (GHG). The MFCS footprint includes 50% landscaping. The water used for irrigation is from non-clinical/non-potable water, treated condensate water, a by-product of air conditioning. For 5 months per year, there is a predicted non-potable water deficit, so costly and non-sustainable desalinated potable water is required for irrigation. The findings include that there is a non-potable water deficit due to an excessive consumption for landscape irrigation (LI) and water features (WF), and that 177,288 m³ of condensate and desalinated water was wasted (equivalent to 71 Olympic swimming pools). The contribution of this research is to demonstrate that water wastage, a contributor to GHG emissions, is due to inadequate field testing and verification, water tank storage problems and a lack of LI and WF water demand management. Strategies to address these issues are suggested and will be useful to building owners, operations and maintenance teams and facility managers to substantially decrease water consumption in any type of buildings with a non-potable water system, as well as helping AD to achieve its target of a 22% reduction in GHG emissions by 2030 (Environment Agency- Abu Dhabi (EAD 2017)).

Spatial heterogeneity is an important aspect to be studied in infectious disease models. It takes two forms: one is local, namely diffusion in space, and other is related to travel. With the advancement of transportation system, it is possible for diseases to move from one place to an entirely separate place very quickly. In a developing country like India, the mass movement of large numbers of individuals creates the possibility of spread of common infectious diseases. This has led to the study of infectious disease model to describe the infection during transport. An SIRS-type epidemic model is formulated to illustrate the dynamics of such infectious disease propagation between two cities due to population dispersal. The most important threshold parameter, namely the basic reproduction number, is derived, and the possibility of existence of backward bifurcation is examined, as the existence of backward bifurcation is very unsettling for disease control and it is vital to know from modeling analysis when it can occur. It is shown that dispersal of populations would make the disease control difficult in comparison with nondispersal case. Optimal vaccination and treatment controls are determined. Further to find the best cost-effective strategy, cost-effectiveness analysis is also performed. Though it is not a case study, simulation work suggests that the proposed model can also be used in studying the SARS epidemic in Hong Kong, 2003.