2-Hexadecynoic Acid

The hitherto undescribed 2-hexadecynoic acid (III) was prepared by the following route. Dodecylmagnesium bromide was reacted with 2,3-dibromopropene to give 2~:bromop e ntadecene (I) in 35 % yield. Refluxing the bromo compound I with freshly prepared sodium amide in xylene gave pentadecyne(II) in 49 .1 % yiel

2-Hexadecynoic Acid

The hitherto undescribed 2-hexadecynoic acid (III) was prepared by the following route. Dodecylmagnesium bromide was reacted with 2,3-dibromopropene to give 2~:bromop e ntadecene (I) in 35 % yield. Refluxing the bromo compound I with freshly prepared sodium amide in xylene gave pentadecyne(II) in 49 .1 % yiel

The progress toward more sustainable energy, water and environmental systems approaches and applications

This editorial provides an overview of ten scientific articles published as the Special paper selection in Thermal Science. The papers were selected from almost six hundred contributions, presented at the 16th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES 2021), held on October 10-15, 2021 in Dubrovnik, Croatia. The topics covered in the Special paper selection include economics of electricity markets, nuclear technology, repowering of the coal-based power plant, hybrid renewable energy system, sustainable biomass handling and conversion, post-combustion emissions control, and efficient cooling technology. The editorial also emphasised the papers recently published in the Special Issues of leading scientific journals dedicated to the series of SDEWES Conferences

Bioelements and Non-Essential Elements in Honeybees and Their Hemolymph, Larvae, Pupae, Honey, Wax, Propolis and Bee Bread

In our previous research we have explored concentrations of 16 elements in samples collected from 3 different environments: Golija (rural region), Belgrade (urban region) and Zajača (industrial region). These three locations were chosen due to their distinctly different degrees of urbanization and industrialization. Macroelements (Ca, K, Mg, Na), microelements (Cu, Fe, Mn, Zn) and non-essential elements (Al, Ba, Cd, Co, Cr, Ni, Pb, Sr) were determined in the whole body of honeybees, but the major novelty of the research was that hemolymph of the bees was analysed as well. Significant spatial but also seasonal variations in content of bioelements and non-essential elements were observed. These findings have raised several important questions which are addressed in our current study. In order to better understand how bees’ environment does affects concentrations of elements mentioned above, dust and pollen collected from the same locations were analysed. They represent 2 major sources of bio elements and toxic elements for the bees: food and atmospheric deposition. For the better understanding of dynamics of investigated elements the scope of our research was further extended to the analysis of bee bread, honey, crops, wax, propolis, larvae and pupae. The samples were digested in accordance with the US EPA SW-846 Method 3052. Closed microwave digestion system (ETHOS 1, Advanced Microwave Digestion System, Milestone, Italy) was used for digestion with 5 to 8 ml of concentrated HNO3 and 1 or 2 ml of concentrated H2 O2 (depending on the mass and type of the sample). Concentrations of: Al, Ba, Cd, Co, Cr, Cu, Ca, Fe, K, Mg, Mn, Na, Ni, Pb, Sr and Zn were determined by ICP-OES (iCAP 6500Duo, Thermo Scientific). Very low concentrations of: Co, Cr, Cd and Pb, which occurred in some samples were confirmed by ICP-MS (iCAP-Q-ICP-MS, Termo Scientific). Ratios between concentrations in the samples from industrial region and urban region were calculated and compared for different matrices. Concentrations of toxic metals such as Pb and Cd were significantly elevated in dust samples from the industrial site, and similar trend was observed for pollen, bee bread, wax, propolis, and the whole bees. Elevation of concentrations was not observed (or it was present in significantly lesser extent) for the samples of honey, larvae and pupae

Multiphase phenomena in Diesel fuel injection systems

Fuel Injection Equipment (FIE) are an integral component of modern Internal Combustion Engines (ICE), since they play a crucial role in the fuel atomization process and in the formation of a fuel/air combustible mixture, consequently affecting efficiency and pollutant formation. Advancements and improvements of FIE systems are determined by the complexity of the physical mechanisms taking place; the spatial scales are in the order of millimetres, flow may become locally highly supersonic, leading to very small temporal scales of microseconds or less. The operation of these devices is highly unsteady, involving moving geometries such as needle valves. Additionally, extreme pressure changes imply that many assumptions of traditional fluid mechanics, such as incompressibility, are no longer valid. Furthermore, the description of the fuel properties becomes an issue, since fuel databases are scarce or limited to pure components, whereas actual fuels are commonly hydrocarbon mixtures. Last but not least, complicated phenomena such as phase change or transition from subcritical to transcritical/supercritical state of matter further pose complications in the understanding of the operation of these devices

Effects of climate and atmospheric nitrogen deposition on early to mid-term stage litter decomposition across biomes

Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its temporal dynamics are of significant importance, since their effects might change over the course of the decomposition process. Within the TeaComposition initiative, we incubated Green and Rooibos teas at 524 sites across nine biomes. We assessed how macroclimate and atmospheric inorganic N deposition under current and predicted scenarios (RCP 2.6, RCP 8.5) might affect litter mass loss measured after 3 and 12 months. Our study shows that the early to mid-term mass loss at the global scale was affected predominantly by litter quality (explaining 73% and 62% of the total variance after 3 and 12 months, respectively) followed by climate and N deposition. The effects of climate were not litter-specific and became increasingly significant as decomposition progressed, with MAP explaining 2% and MAT 4% of the variation after 12 months of incubation. The effect of N deposition was litter-specific, and significant only for 12-month decomposition of Rooibos tea at the global scale. However, in the temperate biome where atmospheric N deposition rates are relatively high, the 12-month mass loss of Green and Rooibos teas decreased significantly with increasing N deposition, explaining 9.5% and 1.1% of the variance, respectively. The expected changes in macroclimate and N deposition at the global scale by the end of this century are estimated to increase the 12-month mass loss of easily decomposable litter by 1.1-3.5% and of the more stable substrates by 3.8-10.6%, relative to current mass loss. In contrast, expected changes in atmospheric N deposition will decrease the mid-term mass loss of high-quality litter by 1.4-2.2% and that of low-quality litter by 0.9-1.5% in the temperate biome. Our results suggest that projected increases in N deposition may have the capacity to dampen the climate-driven increases in litter decomposition depending on the biome and decomposition stage of substrate. © Copyright © 2021 Kwon, Shibata, Kepfer-Rojas, Schmidt, Larsen, Beier, Berg, Verheyen, Lamarque, Hagedorn, Eisenhauer, Djukic and TeaComposition Network

Innovation and advancement of thermal processes for the production, storage, utilization and conservation of energy in sustainable engineering applications

This vision article accompanies a special issue of Applied Thermal Engineering dedicated to the 16th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) held in Dubrovnik in 2021, and summarizes a selection of papers presented at the conference. At the focal point are a range of topics related to thermal processes as these arise in energy production, storage, utilization and conservation, covering fundamental research, the development of technical solutions for diverse sustainable engineering applications, technoeconomic analyses, and issues relating to the potential and integration of technologies from higher-level approaches. Thermal processes are the basis of numerous sustainable engineering applications and their understanding and improvement are increasingly required in the context of improved resource use efficiency and reduced environmental impact. Applications of interest include thermal systems used in buildings, thermochemical processes, seawater treatment, thermal storage solutions and renewable energy resource use. Emerging challenges in this space have given an opportunity to scientists, researchers and engineers to actively contribute to the development of relevant technological solutions, which are covered briefly in the present article

FDI spillover effects on innovation activities of knowledge using and knowledge creating firms: Evidence from an emerging economy

The beneficial effects of innovation for firm performance and competitiveness are well established but it has been suggested in recent years that innovation regimes differ between advanced and emerging economies. While advanced economies rely on knowledge generation, their emerging counterparts follow mainly knowledge use regime through the application of existing knowledge and technology. Climbing up the technological ladder can be helped through spillovers from foreign investors to local firms. We investigate whether FDI spillovers influence different phases of innovation process (from decision to innovate to productivity) among knowledge using and knowledge creating firms in an emerging European economy. The results show that innovation process in emerging economies is closer to imitation than creation of novel products. Local firms benefit from foreign counterparts in the early phase of innovation process. Stronger FDI effects are found on firms that undertake innovation through knowledge use than through knowledge generation

Innovation and advancement of thermal processes for the production, storage, utilization and conservation of energy in sustainable engineering applications

This vision article accompanies a special issue of Applied Thermal Engineering dedicated to the 16th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) held in Dubrovnik in 2021, and summarizes a selection of papers presented at the conference. At the focal point are a range of topics related to thermal processes as these arise in energy production, storage, utilization and conservation, covering fundamental research, the development of technical solutions for diverse sustainable engineering applications, technoeconomic analyses, and issues relating to the potential and integration of technologies from higher-level approaches. Thermal processes are the basis of numerous sustainable engineering applications and their understanding and improvement are increasingly required in the context of improved resource use efficiency and reduced environmental impact. Applications of interest include thermal systems used in buildings, thermochemical processes, seawater treatment, thermal storage solutions and renewable energy resource use. Emerging challenges in this space have given an opportunity to scientists, researchers and engineers to actively contribute to the development of relevant technological solutions, which are covered briefly in the present article

Thermogravimetric and kinetic analysis of biomass and polyurethane foam mixtures Co-Pyrolysis

Alternative fuels are crucial for the decarbonisation of high-energy demanding processes. The utilisation of waste materials to produce alternative fuels is especially interesting since, the co-pyrolysis of waste plastics and biomass was lately introduced as promising method since the synergistic effect might enhance the product properties compared to those from individual pyrolysis. Furthermore, the utilisation of waste biomass, like sawdust, is interesting since it does not influence the sustainability of biomass consumption, and even more, it avoids the usage of raw feedstock. Thermogravimetric analysis is per -formed to determine the thermal degradation behaviour and kinetic parameters of investigated mixtures to find the most appropriate utilisation method. Co-pyrolysis was conducted for three mixtures with the following biomass/polyurethane ratios: 75-25%, 50-50%, 25-75%, over a temperature range of 30-800 degrees C, at three heating rates 5,10 and 20 degrees C/min, under an inert atmosphere. Obtained results were subjected to comprehensive kinetic analysis to determine effective activation energy using the iso-conversional model-free methods and provide a detailed analysis of the samples' thermal degradation process. This work aimed to identify the main thermal decomposition stages during co-pyrolysis of biomass and polyurethane mixtures and provide the mixture composition's influence on the considered thermochemical conversion process