Modeling and experimental verification of operation of supercapacitors with carbon electrodes in non-aqueous electrolytes. The energy efficiency
Charge-discharge processes of supercapacitor with carbon black KJEC 600/Li in non-aqueous electrolyte: 1 M LiPF6 in a mixture of ethylene carbonate (1/3), diethyl carbonate (1/3), dimethyl carbonate (1/3) are investigated. Galvanostatic cycling was carried out in the range from 1 to 4 V with currents from 100 to 5000 mA/g of carbon black. The maximum discharge capacity of 196 F/g has been reached. The porous structure and hydrophilic-hydrophobic properties of carbon black KJEC 600 were investigated by the standard contact porosimetry method (MSCP). The following values were obtained: total specific surface area of 2500 m2/g, total porosity of 7.8 cm3/g, hydrophilic porosity of 4.9 cm3/g, hydrophobic porosity of 2.9 cm3/g. The obtained experimental dependence of the energy efficiency has a maximum (80%) at a current of 250 mA/g. Mathematical modeling of charge-discharge processes of the supercapacitor is developed with taking into account the charging of the double electric layer (EDL) and adsorption of lithium ions according to the Butler-Volmer equation and the Frumkin isotherm for the carbon electrode are taken into account. From the comparison of the calculated and measured charge-discharge curves it follows that these curves are satisfactorily consistent with each other, which indicates the correctness of the model. The density of the exchange current and the specific capacitance of the EDL refereed to the true surface found by the fitting are equal to i0,ad = 2.8 × 10−29A/сm2 and Cdl = 3.5 μF/сm2 respectively.
On the basis of the developed model for different specific currents the energy efficiency dependences on the exchange current density of the adsorption reaction were calculated. Interestingly, these dependencies have a minimum. Based on the model, the profiles of the potential the surface coverage of lithium ions were also calculated.
The given study is devoted to the issues of searching the ways for adaptation to climate change, mitigation of its impact on the economy and population, as well as to the role of increasing energy efficiency in the economies of some countries of Eastern Europe, Caucasus and Central Asia (EECCA). It also relates to the issues of responding to negative trends and emerging challenges caused by climate change. The Report represents several case studies on the above topics implemented in Moldova, Tadjikistan, Kazakhstan, Azerbaijan and the Russian Federation by the network of regional enviuronmental centres. It also contains consideration of possible methodological approaches and recommendations on addressing the above issues in the EECCA region.
The article discusses the features of energy service contracts as one of the types of state-business interaction in the form of a publicprivate partnership. The purpose of the article is to analyze the main problems accompanying the implementation of energy service contracts on the basis of a case analysis and to develop recommendations for those who are at the stage of concluding such agreements. The following causes of problems between the parties to the energy service contracts are highlighted: methodological, organizational and financial. The following recommendations are developed based on the experience of participation in forensic examinations:1) careful study of the methodology for calculating savings using energy audit;2) the method of calculating the economic effect should be an integral part of the energy service contract;3)careful management of documents in order to be able to begin to resolve the conflict in the pretrial order according to the Civil Code;4) the contractor must make sure that there are economic benefits based on detailed calculations of indicators such as payback period, net present value of the project, internal rate of return, which it is mandatory to compare with the cost of financial resources used in the project.
This paper proposes a method of allocation of grant funds within the scientific and academic groups. We consider the allocation process automation through the use of Internet technologies. The study was conducted on the basis of scientific and educational group «Theoretical Foundations of energy efficient wireless sensor networks», National Research University «Higher School of Economics».
Energy efficiency in household sector has recently become an issue of pressing topicality according to the latest studies and reviews in this domain. The issue can be found in numerous publications of the renowned scientists of the past and nowadays it is still receiving a wide support. There are a number of circumstances connected with the emergence of this phenomenon. Firstly, energy consumption of households in Russia and UK is constantly growing. This is true for many other sectors in both countries as well as worldwide. The Statistical Review of World Energy released by British Petroleum in June 2013 states that global consumption of primary energy grew by 60% over the last 25 years and the growth is continuing. It is expected that by 2035 global consumption will grow by 41%. Secondly, energy strategies of both countries call switching to the path of innovative and energy-efficient development one of the main objectives of household sector development. The paper intends to draw attention towards the energy efficiency issue. The paper observes existing energy efficiency problems in household sector in Russia and United Kingdom and governmental programmes that serve to address them. It also considers the peculiarities of energy efficiency programmes of these countries. The paper shows the distinctive and similar features of legislation and policies in energy efficiency area in Russia and United Kingdom. The research reveals each country’s good practices in household sector that can be adopted for another country and can contribute to sector development.
The analysis of energy systems is of paramount importance in modern societies, since it is fundamental to guarantee a sustainable economic development. It combines technical and economic research with a specific focus on quantitative modelling, in order to optimize the modalities of energy demand and supply globally.
The book covers major advanced topics related to the analysis of energy by considering different aspects, namely management, planning and policies. The most recent trends, such as smart grids, transition from fossil fuels to renewables based energy systems and distributed generation, are also discussed in this book. Intended to be a collection of various contributions from experts all around the world, it includes latest research results, innovations and methodologies about the analysis of energy systems. The book also focuses to contribute to the current debate related to the evolution of energy systems, by discussing in an open way the pro’s and con’s without any pre-constitute point of view. Title is aimed to be a reference for the academic community, students and professionals with a wider interdisciplinary background.
The article studies the current Russian and world experience in the state policy in energy saving stimulation. The article analyses the latest changes in Russian legislation in this area. The paper underlines that a number of policy measures used abroad have not been yet implemented in Russia. The paper concludes that the study of foreign experience is extremely important as it helps to boost the transition to the energy-effective economy.
This article analyzes the possible applications of the system provide automated access to electricity in public places “Public socket”, identifies the technical requirements for this kind of systems, assesses the volumes of market segments, analyzes competing technologies and generates recommendations to promote this product to market.
Research area is automated systems to provide users with access to electricity in public places, including for charging mobile devices.
Improvement of the energy efficiency of a national economy greatly enhances energy security of the state, improves the environment and the quality of life of the population and contributes to the social and economic development of any country. Energy efficiency is often the least expensive means of meeting new energy demand. Governments of countries that contribute to increased investment in activities aimed at improving energy efficiency and implementing a set of government support measures that determine reduction in the energy intensity of GDP of the countries, significantly save budgetary funds, reduce dependence on energy imports and reduce environmental pollution. All that in combination leads to an improvement in the indicators of sustainable development not only of individual territories, but also of the national economy as a whole. Nevertheless, measures to improve energy efficiency still do not have the desired effect on a global scale, despite proven numerous advantages and potentials to be the largest resource to meet the growing demand for energy around the world.Energy service contracts are the actual energy saving instruments which have proved their success in many economically developed countries of the world. In Russia, the market for energy services is in the process of formation and is significantly inhibited by the negative impact from a number of groups of factors.
The proceedings of International Congress REENCON-XXI "Renewable energy in 21st Century: energy and economic effectiveness" 2016 presents the thesis of Congress participants devoted to the key aspects of development and practical use of renewable energy sources in Russia and the world. One of the challenges relates to deep decarbonization of the world economy aiming at mitigation of global climate change.
We have performed a comparative analysis of the bio-oil produced by thermal liquefaction of microalgae in different solvents using high-resolution Orbitrap mass spectrometry and GC-MS approach. Water, methanol, ethanol, butanol, isopropanol, acetonitrile, toluene, and hexane were used as solvents in which the liquefaction was performed. It was observed that all resulting oils demonstrate a considerable degree of similarity. For all samples, compounds containing 1 and 2 nitrogen atoms dominated in the positive ESI spectra, while a relative contribution of other compounds was small. In negative ESI mode, compounds having 2 to 7 oxygens were observed. Statistical analysis revealed that products can be combined in two groups depending on the solvent used for the liquefaction. To the first group, we can attribute the products obtained by using protic (alcohols) and to the second by using aprotic (acetonitrile, toluene) solvents. Nevertheless, based on our results, we concluded that solvent possesses a minor impact on molecular composition of bio-oil. We suggested that the driving force of the liquefaction reaction is the thermal dehydration of the carbohydrate in algae, resulting in water formation, which could be the trigger of the producing of bio-oil. To prove this hypothesis, we performed the reaction with the dry algae in the absence of the solvent and observed the formation of bio-oil.
This volume, being the 55th of this Series, contains a wealth of information on bioactive natural products. In Chapter 1, Watson and colleagues have discussed the synthesis of monoterpene indole alkaloids, an important class of structurally diverse natural products, with respect to conventional and biomimetic synthetic approaches.
Titanocene(III) has been widely used in the synthesis of complex organic molecules and natural products including polyketides, phenylpropanoids, antibiotics, and alkaloids. Oltra and coworkers have provided a review on the stereoselective synthesis of natural products facilitated by titanocene(III) in Chapter 2.
About 70 biologically active macrocyclic bisbibenzyls (MBBs) have been isolated and structurally elucidated during the last 30 years. Song and Zhao, in Chapter 3, have provided a review on the synthesis of MBBs with diverse pharmacological properties.
Diabetes mellitus is the most common endocrine/metabolic disorder that poses a global health concern. Reyes and colleagues have discussed the hypoglycemic activity of some terrestrial and marine bioactive compounds with potential for treating type 2 diabetes in Chapter 4. In Chapter 5, Pietruszka and coworkers have highlighted the importance of some marine oxylipins that exhibit different bioactive properties.
Depression has become a psychiatric disorder, which leads to various disabilities. Natural compounds like polyphenols and terpenoids have antioxidant and neuroprotective properties and can be used for the treatment of depression. In Chapter 6, Rodrigues et al. review the clinical studies and trials on polyphenols and terpenoids for the treatment of various psychiatric disorders. The lipid A phosphate and their phosphorylated analogues found in Gram-negative bacteria are of major importance because they provide the host with defense against infections from various microorganisms. Paradies and Zimmermann have discussed physical characteristics, isolation, and bioactivity of lipopolysaccharides (lipid A) for developing new vaccines and therapeutics in Chapter 7.
Hydroxycinnamic acids (HCAs) are a group of phytonutrients with numerous beneficial effects on human health that are largely derived from plants. HCAs play important roles like defense against UV rays or pathogenic attack during growth and development of plants. In Chapter 8, El-Seedi and colleagues present a review focusing on the therapeutic effects of HCAs for the treatment of cancer, diabetes, pulmonary, hepatic, neuro-, and cardiovascular diseases. In Chapter 9, Pomilio and Mercader have presented the study of natural anthocyanins and other related flavonoids for the readers, highlighting their possible and preferable uses as health-protecting food dyes over synthetic ones. They have also discussed the anthocyanins isolated from Ipomoea cairica along with their QSAR studies.
Cardiovascular diseases are considered to be a major threat to health. Polyphenols and carotenoids are structurally diverse groups of bioactive compounds isolated from fruits and vegetables, carrying protective effects against endothelial dysfunction. These therapeutic effects have been explored by Yamagata in Chapter 10.
The roots of licorice and ivy leaves have been used in folk medicine and drugs since long. The biological activity of these complexes has been discussed by Yakovishin and Grishkovets in Chapter 11. In Chapter 12, the chemical and biological characteristics of amicoumacins and xenocoumacins are reviewed by Korshun et al. with reference to the preparation of antibiotics.
I hope that this volume will be received with the same enthusiasm as the earlier volumes of this long-standing series the first volume of which was published under my Editorship in 1988. I would like to express my gratitude to Ms. Taqdees Malik and Mr. Mahmood Alam for their assistance in the preparation of this volume.
The hydrogenation of diphenylacetylene (DPA) on palladium–silver catalysts with a single-atom structure was investigated. It has been shown experimentally that the reaction rate of alkene to alkane hydrogenation is substantially lower than the rate of DPA semi-hydrogenation. The kinetic barriers of all stages of hydrogenation were calculated by the DFT method.
In situ XRD and NMR experiments combined with molecular dynamics simulations using the grand canonical ensemble (GCMD) show that cation size, charge and solvation energy play critical roles in determining the interlayer expansion of smectite clay minerals when exposed to dry supercritical CO2 under conditions relevant to the earthâ€™s upper crust, petroleum reservoirs, and geological CO2 sequestration conditions (323 K and 90 bar). The GCMD results show that the smectite mineral, hectorite, containing interlayer alkali and alkaline earth cations with relatively small ionic radii and high solvation and hydration energies (e.g., Li+, Na+ Mg2+, and Ca2+) does not intercalate dry CO2 and that the fully collapsed interlayer structure is the energetically most stable configuration. With increasing cation size and decreasing cation solvation energy, the energy barrier to CO2 intercalation decreases. With K+, Rb+, Cs+, Sr2+, and Ba2+ the monolayer structure is the stable configuration, and CO2 should spontaneously enter the interlayer. With Cs+ there is not even an energy barrier for CO2 intercalation, in agreement with the experimental XRD and NMR results that show clay layer expansion and CO2 incorporation. The number of intercalated CO2 molecules decreases with increasing size of the alkali cation but does not vary with ion size for the alkaline earth cations. 13C NMR spectroscopy and the GCMD simulations show that the average orientation of the intercalated CO2 molecules is with their O-C-O axes parallel to the basal clay surface and that they undergo a combination of rapid rotation about an axis perpendicular to the main molecular axis and wobbling motion with respect to the basal surface. Incorporation of CO2 in the interlayer decreases the coordination of Cs+ by the oxygen atoms of the basal surfaces, which is compensated by CO2 molecules entering their solvation shell, as predicted based on previously published NMR results. The GCMD simulations show that the strength of the interaction between the exchangeable cation and the clay structure dominates the intercalation energetics in dry scCO2. With relatively small cations, the cation-clay interactions outcompete cation solvation by CO2 molecules. The computed residence times for coordination among of interlayer species are consistent with the computed energetics.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.