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The structure and operating principle of a four-stroke internal combustion engine are usually demonstrated using the cut-away model of an internal combustion engine or its computer animation. However, by observing the operation of the engine mechanism, the understanding of the main essence, which consists of the transformation of thermal energy from the combustion of gasoline into the mechanical energy of the piston movement is lost. This work describes the demonstration of the ignition and combustion of the fuel mixture and the transformation of thermal energy generated by the combustion of gasoline into the mechanical energy of the piston. A paper rocket is used instead of a piston for the spectacle of the experiment. This demonstration does not leave anyone from the audience indifferent. The dependence of rocket flight height on the mass of burned gasoline was established. [ABSTRACT FROM AUTHOR]

This paper provides a legal analysis of the direct line in the legislation of the European Union. The direct line, serving as a legal instrument to implement off-grid solutions, plays a crucial role in amplifying competition within the energy market. Compared to other instruments introduced by the First Liberalization Package in 1992, the direct line is not a subject commonly brought about by legal literature. The core part of legal analyses is divided into two parts, which focus on different approaches of direct line, i.e., European Union and selected Member States (Estonia, Latvia, Lithuania, and Poland). The motives of the Union in establishing the direct line instrument was to support opening the energy market to increase energy generating units. During the transposition of the direct line into national laws, analysed countries have directed the usage of this mechanism to promote renewable energy sources. The presented case studies create a rare pattern of how the Member States form their own interpretations and hence use the Union law in practice, which differs from the direction established in the Union forum. The research focused on legal dogmatic examining of regulations at both European and national levels, with a particular emphasis on the definition part while figuring a crucial role in shaping the direct line concept. The paper also presents other convoluted legal schemes, such as the permit issuance process for direct line construction. The conclusions assess the modifications in the European Union regime, but also their impact on electricity prices and green investments. [ABSTRACT FROM AUTHOR]

In light of China's rapid growth and increasing engagement in the global climate regime, the authoritarian regulatory model has attracted attention from researchers and policymakers alike. This paper examines the question of to what extent and in what way state authoritarianism leads to (un)successful environmental policy implementation in China, with particular attention to energy transformation. This study inter-connects macro and micro inquiries through a case study of nuclear energy policy in China. An examination of the extended policy cycle as a comprehensive process that brings a policy to fruition shows that authoritarian regulatory environmental policy intervenes in each stage, resulting in a particular path of the evolution of environmental policy in nuclearising energy transformation in China. Adding to commonly accepted tenets of authoritarian environmentalism in general, the explanations of Chinese distinctiveness in materialising environmental policy enhances the understanding of the merits and challenges of authoritarian mechanisms of environmental policy. [ABSTRACT FROM AUTHOR]

When solving open-region electromagnetic scattering problems using the standard finite element method, the infinite region exterior to the scatterer must be truncated with an artificial outer boundary. In the interior or finite part of the domain, finite elements can be used, but a boundary condition must be introduced at this artificial boundary to obtain a unique finite element solution. One class of boundary conditions designed for this purpose is called absorbing boundary conditions (ABCs). Several ABCs have been reported in the literature. These can be broadly classified into two categories: local and non-local. In this paper, we present new closed-form expressions for Nth-order local ABCs, equivalent to the well-known sequences of the Bayliss, Gunzburger, and Turkel boundary operators. To the best of our knowledge, these expressions have not yet been reported in the literature. Two- and three-dimensional problems are considered in this study. We also discuss the problem of incorporating custom ABCs into commercial finite element method programs, which are usually closed-source software packages. Two 2D electromagnetic scattering and radiation problems with known analytical solutions are analyzed. [ABSTRACT FROM AUTHOR]

Hydrogen energy has an advantage over conventional fossil energy because of its clean and low-carbon features, while its stability gives it an advantage over renewable energy sources such as hydropower, photovoltaic (PV) power, and wind power. Using hydrogen as a fuel can achieve zero carbon emissions or even net zero emissions at the end of energy conversion. Moreover, with hydrogen as the carrier, an energy system of multi-energy complementarity will be established by coupling multiple energy systems such as power grids, gas grids and heat networks, which can realize the comprehensive utilization of renewable energy sources in an efficient, stable, and flexible manner. Based on the "dual carbon" goals, this paper targets sectors with high carbon emissions represented by electric power, steel and transportation, analyzes the feasible path of using hydrogen energy to promote deep carbon reduction, and points out the obstacles faced by hydrogen energy development in various sectors. On account of the current development and expected prospects, this paper proposes that the current focus of hydrogen energy industry is to coordinate the development of industrial sectors and regions, build a pattern that can facilitate the industry's systematic and concerted development, address key technical challenges (such as green hydrogen production or hydrogen storage and transportation via pipeline), improve industrial standards, and promote the industry's development in a balanced, coordinated and orderly way. [ABSTRACT FROM AUTHOR]

The transformation of the European energy sector is becoming a priority for the European Union. This is indicated, for instance, in the European Union strategy known as the European Green Deal. According to the Green Deal, the area of 'research and innovation' is one which can counteract climate change. Universities can play a significant role in this by adopting a pedagogical approach aimed at mobilizing the spirit of innovation and entrepreneurship in young professionals. In addition to modifying curricula related to mining, energy, and environmental engineering, i.e., activities in recognized, traditional schemes, one prospective tool may be the involvement of students and PhD candidates in European initiatives such as the InnoEnergy PhD School (which is funded by the European Institute of Innovation and Technology). This paper aims to discuss the InnoEnergy PhD School programme as a possible instrument for mitigating the negative effects of energy transformation. The article analyzes the programme using a case study method, including surveys and open interviews. The paper draws attention to and highlights the role of human resources in the field of education and the stimulation of innovation, as well as the need to strengthen the business component in the education of PhD candidates. [ABSTRACT FROM AUTHOR]

Background: Formative assessments are needed to enable monitoring how student knowledge develops throughout a unit. Constructed response items which require learners to formulate their own free‐text responses are well suited for testing their active knowledge. However, assessing such constructed responses in an automated fashion is a complex task and requires the application of natural language processing methodology. In this article, we implement and evaluate multiple machine learning models for coding energy knowledge in free‐text responses of German K‐12 students to items in formative science assessments which were conducted during synchronous online learning sessions. Dataset: The dataset we collected for this purpose consists of German constructed responses from 38 different items dealing with aspects of energy such as manifestation and transformation. The units and items were implemented with the help of project‐based pedagogy and evidence‐centered design, and the responses were coded for seven core ideas concerning the manifestation and transformation of energy. The data was collected from students in seventh, eighth and ninth grade. Methodology: We train various transformer‐ and feature‐based models and compare their ability to recognize the respective ideas in students' writing. Moreover, as domain knowledge and its development can be formally modeled through knowledge networks, we evaluate how well the detection of the ideas within responses translated into accurate co‐occurrence‐based knowledge networks. Finally, in terms of the descriptive accuracy of our models, we inspect what features played a role for which prediction outcome and if the models pick up on undesired shortcuts. In addition to this, we analyze how much the models match human coders in what evidence within responses they consider important for their coding decisions. Results: A model based on a modified GBERT‐large can achieve the overall most promising results, although descriptive accuracy varies much more than predictive accuracy for the different ideas assessed. For reasons of comparability, we also evaluate the same machine learning architecture using the SciEntsBank 3‐Way benchmark with an English RoBERTa‐large model, where it achieves state‐of‐the‐art results in two out of three evaluation categories. Lay Description: What is already known about this topic?: Formative assessments are needed to test and monitor the development of learners' knowledge throughout a unit to provide them with appropriate automated feedback.Constructed response items which require learners to formulate their own free‐text responses are well suited for testing their active knowledge.Assessing constructed responses in an automated fashion is a widely researched topic, but the problem is far from solved and most of the work focuses on predicting holistic scores or grades.To allow for a more fine‐grained and analytic assessment of learners' knowledge, systems which go beyond predicting simple grades are required.To guarantee that models are stable and make their predictions for the correct reasons, methods for explaining the models are required. What this papers adds?: A core topic in physics education is the concept of energy.We implement and evaluate multiple systems based on natural language processing technology for assessing learners' conceptual knowledge about energy physics using transformer language models as well as feature‐based approaches.The systems assess students' knowledge about various forms of energy, indicators for the same and the transformation of energy from form into another.As our systems are based on machine learning methodology, we introduce a novel German short answer dataset for training them to detect the respective knowledge elements within students' free‐text responses.We evaluate the performance of these systems using this dataset as well as the well‐established SciEntsBand‐3‐Way dataset and manage to achieve, to our best knowledge, new state‐of‐the‐art results for the latter.Moreover, we apply methodology for explaining model predictions to assess whether predictions are carried out for the correct reasons. Implications for practice and/or policy: It is indeed possible to assess constructed responses for the demonstrated knowledge about energy physics in an analytic fashion using natural language processing.Transformer language models can outperform more specialized feature‐based approaches for this task in terms of predictive and descriptive accuracy.Co‐occurrences of different concepts within the same responses can lead models to learn undesired shortcuts which make them unstable. [ABSTRACT FROM AUTHOR]

Currently, hydrogen and electric drives used in various means of transport is a leading topic in many respects. This article discusses the most important aspects of the operation of vehicles with electric drives (passenger cars) and hydrogen drives. In both cases, the official reason for using both drives is the possibility of independence from fossil fuel supplies, especially oil. The desire for independence is mainly dictated by political considerations. This article discusses the acquisition of basic raw materials for the construction of lithium-ion batteries in electric cars, as well as methods for obtaining hydrogen as a fuel. The widespread use of electric passenger cars requires the construction of a network of charging stations. This article shows that, taking into account the entire production process of electric cars, including lithium-ion batteries, the argument that they are ecological cannot be used. Additionally, it was indicated that there is no concept for the use of used accumulator batteries. If hydrogen drives are used in trains, there is no need to build the traction network infrastructure and then continuously monitor its technical condition and perform the necessary repairs. Of course, the necessary hydrogen tanks must be built, but there must be similar tanks to store oil for diesel locomotives. This paper also deals with other possibilities of hydrogen application for transformational usage, e.g., the use of combustion engines driven with liquid hydrogen. Unfortunately, an optimistic approach to this issue does not allow for a critical view of the whole matter. In public discussion, there is no room for scientific arguments and emotions to dominate. [ABSTRACT FROM AUTHOR]

Hydrogen can be considered an innovative fuel that will revolutionize the energy sector and enable even more complete use of the potential of renewable sources. The aim of the paper is to present the challenges faced by companies and economies that will produce and use hydrogen. Thanks to the use of hydrogen in the energy, transport and construction sectors, it will be possible to achieve climate neutrality by 2050. By 2050, global demand for hydrogen will increase to 614 million metric tons a year, and thanks to the use of hydrogen in energy, transport and construction, it will be possible to achieve climate neutrality. Depending on the method of hydrogen production, the processes used and the final effects, several groups can be distinguished, marked with different colors. It is in this area of obtaining friendly hydrogen that innovative possibilities for its production open up. The costs of hydrogen production are also affected by network fees, national tax systems, availability and prices of carbon capture, utilization, and storage installations, energy consumption rates by electrolyzers and transport methods. It is planned that 1 kg of hydrogen will cost USD 1. The study used the desk research method, which made it possible to analyze a huge amount of descriptive data and numerical data. [ABSTRACT FROM AUTHOR]

Cohesion and rolling friction play key roles in governing the behavior of soil; however, only a limited number of studies have been able to assess the simultaneous contributions of these two microparameters on the macroproperties of soil. In this respect, the innovation of the current study includes an attempt to examine the interplay of these two primary parameters on the angle of repose (AoR) based on the discrete-element method (DEM). Lifting cylinder tests on cohesive wet sand have been carried out in DEM, while the cohesion and rolling friction are captured through proposed computational models. In this paper, macroparameters, such as the geometry and developmental stages of sand piles obtained in DEM simulation, are compared with experimental data, while their microevolution is quantified in detail. The results show that a large AoR can only be obtained when the cohesive and rotational frictional forces work in tandem. Increasing the cohesion and rolling friction results in smaller contact numbers, with increasing chain-like connections between particles and larger pore spaces to account for a larger AoR. For the first time, this study distinctly identifies three major stages that contribute to the AoR, based on the development of contact numbers and the transformation of energy. Accordingly, the linkage between macroscale AoR and the microstructural coordination number is formulated with varying levels of cohesion and rolling friction. The DEM results prove that the more cohesive the particles are, the greater the delay in the dissipation of kinetic energy. [ABSTRACT FROM AUTHOR]

In this paper, we present a numerical study of dynamic behavior of rock avalanche by using three-dimensional particle flow simulation. The emphasis is put on the influence of particle shape, size and gradation on the velocity and energy transformation process of falling rock clusters. A new numerical method is first developed for the three-dimensional reconstruction of rock clusters. A new approach is also proposed for the analysis of falling motion of rock clusters based on different energy transformation processes. A series of numerical calculations are performed with rock clusters composed of particles with different geometrical shapes, sizes and gradation. The influences of these factors on the velocity and energy transformation process are presented and analyzed. The obtained results suggest that the increase in irregularity degree of particle shape of rock clusters reduces the average velocity and collision-induced energy dissipation; for a certain volume of clusters, the decrease in particle size has little effect on the average velocity but significantly enhances friction-related energy dissipation; the impact of gradation is relative complex depending on the combination of shape and size of particles in rock clusters. [ABSTRACT FROM AUTHOR]

Employment and the competencies of employees in the energy sector are coming into particular prominence in economies around the world. It is one of the few sectors positively affected by the COVID-19 pandemic. As a result, a significant global change in the awareness of society occurred in favor of increasing pro-health and pro-environmental activities, which can be seen in the green transformation. Poland can also boast such changes in recent years, as evidenced by the dynamic development of renewable energy sources (boom for photovoltaics) and the increase in prosumption. Correlated with this is the increase in demand for employees with specific competencies, the so-called multi-competencies that are a compilation of technical, business, and soft and hard competencies, as well as interdisciplinary ones. The paper emphasizes the need to better adjust the education system to the real needs of the labor market in a turbulent environment with the use of the Sectoral Qualifications Framework in Energy, developed in cooperation with stakeholders from the industry. Therefore, the authors analyzed the employment structure in the energy sector in Poland, with particular emphasis on the factors and conditions of this structure and made an attempt to identify and create a competency profile of employees in this area. For the purposes of this article, two key research problems were formulated: What are the key competencies of employees in the energy sector? How is employment changing in this area? The following research hypothesis was also put forward: The transformation of the energy sector towards green energy affects the increase in employment in this area and the increase in the demand for soft competencies. The analysis was based on statistical data, reports, job advertisements, and a review of the results of empirical research to date. [ABSTRACT FROM AUTHOR]

The loading system stiffness (LSS) of a rock mechanics testing machine is important in laboratory testing because it dictates whether the coal or rock failure process is stable or unstable. It is also critical to ejection kinetic energy after coal specimen failure. When unstable failure accidents such as rock burst occur in rock engineering, the speed of ejected coal or rock may reach or even exceed 10 m/s. Such unstable failures, if unplanned, can result in injuries of workers, damage to equipment and delays in production in underground mines. To systematically study the influence of the LSS on mechanical characteristics and kinetic energy of coal specimens, tests are first carried out using an LSS-variable testing system named BGYD-600. PCI-2 acoustic emission (AE) test system, acceleration sensor and dynamic strain gages are used to monitor the AE signals of coal and deformation, displacement of test machine. And the kinetic energy is calculated by energy analysis method. The test results show that the LSS has influence on the stress–strain curves of coal specimens after the peak strength. The smaller the LSS, the steeper the post-peak curves. In addition, as the LSS decreases, the spalling of coal blocks increases considerably, and the powdery phase begins to appear, and the coal specimen is destroyed at a shorter time with more coal blocks being ejected. Moreover, the maximum AE energy occurred not at the peak strength using the BGYD-600, which is different from the large stiffness testing machines. Finally, considering the impact of the elastic deformation energy release of the testing machine on the coal specimens, the kinetic energy calculation formula when the coal specimen failure is derived. And the influence of LSS on the kinetic energy, elastic deformation energy, dissipation energy and total input energy is analyzed. As the LSS increases, the kinetic energy of the coal specimen shows a decreasing trend. The quantitative relationship between mechanical characteristics, kinetic energy and LSS given in this paper has certain reference value for mining and civil engineering projects. [ABSTRACT FROM AUTHOR]

This paper explores how green fiscal expenditure affects G reen T otal F actor E nergy E fficiency (GTFEE) from both non-spatial and spatial perspectives based on selected panel data of 254 cities in China. The results of the non-spatial panel model indicate that green fiscal expenditure has a significant positive impact on GTFEE. A comparative study of different econometric models shows that the main parts of the results are largely consistent, which indicates that the conclusions are robust. The spatial autocorrelation findings indicate a statistically significant presence of positive spatial spillover effects in the GTFEE of Chinese cities. Spatial Durbin Model (SDM) and Dynamic Spatial Durbin Model (DSDM) indicate that green fiscal expenditure has a similarly significant positive effect on GTFEE, which will increase over time. This paper considers different spatial weight matrices and changing measures to measure GTFEE, and the conclusions remain robust. Furthermore, industrial structure upgrading, and digital economy are vital in strengthening the relationship between local governments' green fiscal expenditure and GTFEE. According to heterogeneity analysis, green fiscal expenditure has a more significant effect on the GTFEE in mature resource-based cities and non-resource-based cities. • Influence factors of green total factor energy efficiency (GTFEE) is explored. • Green fiscal expenditure (GFE) has a significant positive impact on GTFEE. • Significant positive spatial spillover effects exist in the GTFEE of Chinese cities. • Industrial structure upgrading and digital economy are vital for GFE and GTFEE. [ABSTRACT FROM AUTHOR]

This research paper examines the implications of energy imports on green innovation within the context of the Russia-Ukraine war. It utilizes panel data spanning EU countries from 1999 to 2022. Initially, the study explores the influence of natural gas and oil imports on the advancement of green innovation. Specifically, it reveals that the importation of natural gas facilitates progress in this area, whereas the importation of oil can impede such advancement. Following the Russia-Ukraine war, the role of gas imports in fostering green innovation within EU countries has grown, simultaneously exacerbating the adverse effects of oil imports on green innovation. Secondly, by employing a panel threshold model, the study identifies that higher energy prices make natural gas and oil imports unfavorable for the progress of green innovation in EU nations. Thirdly, an analysis of heterogeneity demonstrates that, as a result of the Russia-Ukraine war, natural gas imports have a more significant detrimental effect on the development of green innovation in EU nations with a natural gas dependency ranging from 10% to 90%. In the case of oil imports, EU nations with a dependence on Russian oil exceeding 50% experience a more pronounced negative impact on the development of green innovation. Fourthly, a mechanistic study elucidates that natural gas imports indirectly stimulate green innovation through the mechanism of energy transition, while oil imports hinder the development of green innovation by exacerbating carbon emissions. The empirical findings of this paper carry substantial policy implications for EU nations, urging the acceleration of energy transition in response to the impact of the Russia-Ukraine war on green innovation. Moreover, these findings have broader implications for global environmental management and the collective endeavor to combat climate change. • Natural gas imports can promote green innovation; Oil imports inhibit green innovation; The outbreak of the Russia-Ukraine War reinforced both effects. • Rising energy prices make gas and oil imports a disincentive for green innovation in EU countries. • Natural gas imports indirectly promote green innovation through the energy transition, while oil imports inhibit green innovation by increasing carbon emissions. [ABSTRACT FROM AUTHOR]

Increasing seepage flow causes soil particles to migrate, i.e., from local piping to complete fluidization, resulting in reduced effectives stress and degraded shear stiffness of the soil foundation. This process has received considerable attention in the past years, however, majority of them concentrate on macro-aspects such as the internal erosion and soil deformation, while there is a lack of fundamental studies addressing the energy transport at micro-scale of fluid-soil systems during soil approaching fluidization. In this regard, the current study presents an assessment of the energy evolution in soil fluidization based on the discrete element method (DEM) coupled with computation fluid dynamics (CFD). In this paper, an upward seepage flow of fluid is modelled by CFD based on the modified Navier–Stokes equations, while soil particles are governed by DEM with their mutual interactions being computed through fluid-particle force models. The energy transformation from the potential state to kinetic forms during fluid flowing is discussed with respect to numerical (CFD-DEM) results and the energy conservation concepts. The results show that majority of the potential energy induced by fluid flows has lost due to frictional mechanisms, while only a small amount of energy is needed to cause the soil to fluidize completely. The contribution of rotational and translational components to the total kinetic energy of particles, and their changing roles during soil fluidization is also presented. The effect of boundary condition on the energy transformation and fluidization of soil is also investigated and discussed. [ABSTRACT FROM AUTHOR]

The presented paper shows a hypothetical large solar farm that would be the only source of electricity for the entire country. The energy crisis in Europe raises the question of whether it is possible to supply an electrical system based only on renewable energy sources. What should the surface area of the solar panels be in a hypothetical large solar farm to power the entire country? In this work, we will show what requirements must be met to make this feasible. Very important differences between the installed power capacity in a coal-fired or nuclear power plant and a solar power plant are discussed. The article presents calculations of the surface area of photovoltaic panels in that solar farm for four exemplary countries in Central Europe: Poland, Germany, the Czech Republic and the Slovak Republic. These studies are particularly important for Poland, whose electrical system is still mainly based on coal-fired power plants. The hypothetical solar farm could, in practice, take the form of dozens of solar power plants located in different parts of the country. Most importantly, the proposed solution will counteract climate change. [ABSTRACT FROM AUTHOR]

Establishing conditions that meet climate requirements should be one of the most important goals of the whole world in order to protect against the negative effects of climate change. Without cooperation and considerable commitment from everyone, it is possible that these negative effects will worsen. The implementation of the Energy Policy from now until 2050 should facilitate the transformation of the coal-based power system toward a more sustainable and diversified mix of energy sources. Financial investments in the countries analyzed in this paper create real opportunities and changes for the transition toward renewable energy sources (RES), but there is criticism concerning the insufficient speed of change and the costs of the transformation for society. The dominant emphasis on the optimum selection of energy sources creates conflicts, especially in democratic decision-making. Resource management is both incremental and participatory, and while decisions are strongly based on science, the decision-making process is rarely rational or comprehensive. It is difficult to estimate environmental costs, especially because there is no method for comparing the many criteria between the different energy sources since there are differences in the energy efficiency results obtained in different areas. Public opinion is of great importance and it has a huge influence on the development of the development strategies and policies that are undertaken. Therefore, as part of our analysis, we conducted research using a questionnaire to obtain opinions on fundamental issues regarding the climate and energy strategies that have been adopted in the EU. This was important for achieving the main goal of this article, which is a multidimensional analysis of activities aimed at adapting the national economy to the EU strategies that are responsible for reaching the energy and climate goals by 2050. The low-emission energy transformation is aimed at introducing significant changes for the entire economy while at the same time ensuring the implementation of the so-called European triad of goals (energy security, energy competitiveness and climate protection), which often contradict each other in practice. [ABSTRACT FROM AUTHOR]

The aims of the paper are to identify and assess the determinants of transition to renewable and sustainable energy development in Azerbaijan and Poland. Both countries have a clear target to increase the share of renewable energy sources (RES) in the gross final energy consumption, i.e. Poland in the National Energy and Climate Plan for the years 2021–2030 declares that it wishes to achieve 21–23% by 2030 (total consumption in electricity, heating and cooling as well as for transport purposes). But there are currently significant producers and consumers of conventional energy carriers, respectively coal and oil, and these fuels ensure an appropriate level of energy security and production stability. Moreover, in Poland, the mining sector plays a very important social role, whereas the oil industry in Azerbaijan creates significant budget revenue. Therefore, even with stronger EU and worldwide climate policy and a decreasing cost of cleaner forms of energy, there are many challenges and obstacles for such countries in increasing energy from RES associated with energy security, efficiency, existing infrastructure, competitiveness and social aspects. In order to identify best practices for the transition to decarbonisation, the availability of energy resources, energy market structures, national strategies and policies were compared using PESTEL analysis. [ABSTRACT FROM AUTHOR]

The horizontal axis turbine is one of the most promising energy extractors for tidal stream energy utilization. However, there is no widely accepted model for describing the wake structure of a tidal stream turbine. Besides, the flow velocity variation in wakes is accompanied by energy transformation and has hardly been investigated to date. In this paper, a brief review of existing laboratory tidal stream turbine experiments is first presented, followed by a discussion about the controlling variables that includes cross-comparisons between different results from physical laboratory tests. Theoretical derivation and experimental data analysis are conducted to enable a better understanding of the energy transformation and wake development processes, and tidal stream energy extraction. It has been found that part of the flow kinetic energy has been converted into potential energy before reaching the rotor, commonly used power coefficients are not equivalent when quantifying energy extraction, and it is possible to reconstruct turbine wakes using 3 independent data-based parameters. • Energy transformation from potential energy to kinetic energy occurs even before the flow reaching the rotor. • The widely used energy coefficients based on torque and thrust are not equivalent to each other. • It is possible to reproduce the horizontal and vertical far-wake velocity profiles using 3 independent parameters. [ABSTRACT FROM AUTHOR]

Summary: In order to enhance the fuel economy of hybrid electric vehicles, this paper proposes a novel method for the design and analysis of hybrid electric vehicle powertrain configurations. Initially, by analyzing the energy transformation of hybrid electric vehicle, the single‐mode configurations are designed by considering the engine efficiency, the conversion energy loss, and the mechanical transmission efficiency, respectively. Then, two novel multimode configurations with single electric machine are obtained through integrating the single‐mode configurations. In addition, performance comparison and analysis between the two novel configurations and the improved version of Toyota Prius under Highway Fuel Economy Test and Urban Dynamometer Driving Schedule cycles are conducted. The results indicate that the two novel configurations possess better fuel economy than the improved version of Toyota Prius. This paper analyzes the energy transformation of hybrid electric vehicle and proposes a novel design and analysis method of hybrid electric vehicle powertrain configurations. Through the method, two novel multimode hybrid electric configurations with single electric machine are obtained. [ABSTRACT FROM AUTHOR]

Transitioning electricity generation sectors to renewable energy is a necessary element of climate change mitigation but a challenging one with years of technical and social lock-in creating considerable inertia and a pace of change insufficient to meet the task. Transition management has emerged as a promising approach to proactively manage and accelerate transitions in sectors like energy and water and has the potential to do so in manner that would help secure energy justice. However, the approach has been criticised for ignoring the political dynamics of transitions, risking procedural and recognition injustice for traditional energy production regions while increasing opposition to a transition. This paper uses a qualitative case study approach to understand how a transition to renewable energy generation could be achieved in a way that secures energy justice for traditional energy production regions like those of Gladstone in the Australian state of Queensland. The paper augments the transition management approach with the “just transitions” concept, which has emerged from labour movements as a means to mitigate negative impacts on workers and communities in traditional energy production regions, to create a “Just Transition Management” framework that is applied as a diagnostic tool to the case study. While results suggest a transition is imminent within Queensland, a lack of: consistent, supportive federal policy; long-term visions, and a clear process leaves it at risk of being captured by the powerful incumbent resources sector utilising an “environment vs. jobs” narrative. Yet, the results also suggest that adopting a just transition management approach has the potential to successfully resist the influence of the resources sector, by providing cheap, secure renewable energy and supporting affected workers into roles in the renewable energy sector using a reflexive, representative network governance approach. Data analysis reveals how the application of just transition principles has already engaged communities and unions that were previously sceptical of renewable energy. Overall, this study suggests that the just transition management framework assists in identifying the political barriers to transitions and energy justice more broadly, while also providing a management approach which creates powerful niche actor-networks to counter the narratives and influence of the incumbent resource sector. Thus it could support successful transitions that achieve the distributional, recognition and procedural justice needed for energy justice globally. [ABSTRACT FROM AUTHOR]

Renewable energy can be used from several natural sources, which are capable of wind, sun, water, geothermal springs, or biomass. Energy from these sources is clean, safe and inexhaustible. The use of alternative sources is becoming part of all realistic scenarios and promotes sustainable development and energy security in Europe as well. Renewable energy sources form a relatively significant part of primary energy sources in many countries. Thanks to the undeniable advantages of their use, they form another higher share of combined energy production in Slovakia. In addition, the correct location of renewable energy sources can be a key element in the development of individual regions, which can contribute to achieving better social and economic cohesion in the country. Given these obvious environmental and economic benefits, efficient use of renewable energy sources is receiving increasing attention and support from responsible officials and the general public around the world, including Slovakia. The main goal of this paper was to evaluate the use of renewable resources in Slovakia with a focus on biogas plants. We also evaluate the position of Slovakia within the EU in this area and find out what is the current situation of biogas plants in Slovakia. [ABSTRACT FROM AUTHOR]

The paper deals with the peculiarities of thermodynamic analysis of technological systems of food production with generation of secondary steam. System analysis is based on information about production, equipment operation, modern scientific achievements and modeling methods in chemical, physical, mathematical and other sciences. The information about applied energy and thermodynamic criteria, criteria of optimization of systems, list of sequence of actions on improvement of systems is given. Secondary energy resources of food industries are often represented by thermal energy of liquid media or secondary steam. Regeneration of the secondary steam allows, during its subsequent condensation, to return the heat potential of the steam to the media. This means that in the systems where the increase in the thermodynamic parameters of steam due to its compression, there is the use of Carno's return cycle. Such use occurs both in closed and open cycles. The description of the physical processes accompanying the work of the thermocompressors is subject to mathematical modeling based on the laws of conservation of energy, mass conservation and conservation of impulses. The assessment of the suitability for using secondary energy resources is based on exergy methods in order to determine the directions for their further improvement. For identical pressures in the mixing chamber, the efficiency of the actual compressor is higher than the ratio of the ejection coefficients of the real and ideal compressors, since internal irreversible losses along with the reduction of the ejection rate result in the increase of the specific exergy of the compressed flow. [ABSTRACT FROM AUTHOR]

Impact disturbance and bedding angle have a substantial effect on the mechanical response of sandstone under prestressed loading. Therefore, in this paper, a combined 1D static and dynamic loading test system is employed for examining the compression of sandstone at various bedding angles under a pre-applied axial pressure of 25 MPa. Under these conditions, the strength, stress-strain curves, energy usage ratio, particle size and deformation of sandstone are obtained. The results are as follows. (1) Strain rebound easily occurs in high-strength sandstone under low impact pressure. (2) The peak strength of sandstone is positively correlated with the impact pressure. The peak strength and combined dynamic‒static strength of sandstone change in a "v" shape. (3) The rock's failure particle size is controlled by the bedding plane at low impact pressure. (4) We propose a new energy calculation method in which the energy utilization rate presents an approximately inverted "v" shape. (5) The sandstone with different bedding angles has different bursting liabilities at an identical impact pressure. (6) The impact pressure is proportional to the crack growth rate of sandstone. • A new method for rock energy calculation under dynamic and static loading is proposed. • The induced mechanism of rock burst is explored from the aspect of experiment, and the corresponding preventive measures are put forward. • From the aspect of fracture mechanism, the bedding effect and impact pressure effect of sandstone are studied. [ABSTRACT FROM AUTHOR]

Abstract Participation processes can improve environmental decision-making. However, proving the impact of participation processes – i.e. decision-making involving diverse actors from civil society, business, state, and administration – is challenging. This paper therefore examines participation processes by applying proxy measures that are assumed to strongly correlate with improved environmental decision-making. Such indicators include the perception of the process as being fair and legitimate, the final outcomes being considered effective and efficient, satisfaction with one's own engagement and the development of trust, and conflict resolution. Participation process characteristics such as participation format and facilitation are assumed to have an impact on these indicators. This study examined participation processes in relation to the German energy transformation (Energiewende), asking respondents about their experience of participation, their perception of the process, and also about intermediate outcomes such as trust building and conflict resolution. An online survey was conducted, resulting in 516 valid responses. The results show that participation processes related to the Energiewende are often perceived as fair and legitimate. Moreover, the findings provide a better understanding of the relationships between participation process characteristics and desirable intermediate outcomes, such as trust and conflict resolution, as well as normative process factors. The intensity of a participation process – i.e. whether it is dialogic or a written consultation process – had no significant influence either on normative process factors, such as procedural fairness, or on trust or conflict resolution. Instead, a trustworthy moderator and the integration of all affected interests are important participation process characteristics that could determine the success of the decision-making process. Highlights • The results of an online Survey (N = 516) are presented. • Participation processes related to the German energy transformation are positively perceived. • Participatory approaches can enhance trust building. • Participation has limited capacity to resolve conflicts. • Participation intensity is less important than participants diversity and facilitation. [ABSTRACT FROM AUTHOR]

Abstract A suspended buffer system reduces the out-of-pipe speed of gangue particles to a reasonable value, which prevents damage to the gangue storage silo. During the buffering process, the kinetics energy of gangue particles is dissipated by particle collision and structural damping of the suspended buffer, with the remaining energy being the residual kinetics energy of gangue particles. The ratios of these energies are important indicators of the buffering effect and are the basis for feeding safety judgment. Therefore, it is necessary to reveal the kinetic energy transformation pattern of gangue particles during the collision process. This paper established a numerical kinetic energy transformation model for gangue particles by combining Solidworks and Femap. The simulation results showed that kinetics energy of gangue particles is mainly consumed by the collision between particles and the suspended buffer, while the energy consumed by structural damping of the suspended buffer is relatively small. At the same time, the ratio of energy consumed by particle collision decreases with the increase of gangue particle size, which corresponds to the increasing particle residual kinetic energy. Origin was then employed to fit ratio of energy consumed by collision, particle residual kinetic energy and velocity as functions of particle size: E 1 = 57.19 + 34.48/(1 + e(D -48.89)/7.19), E 2 = 40.57–33.59/(1 + e(D -49.16)/8.14) and v´ = 52.34–51.93/(1 + e(D -50.50)/18.75). Based on the requirement of particle kinetic energy transformation, the reasonable particle size was determined to below 50 mm according to the aforementioned functional relationships. Industrial testing of the simulation result was performed in the Dongping coal mine, which showed good buffering effect while damage of the storage silo was not observed. Graphical abstract Unlabelled Image Highlights • It was revealed that kinetic energy transformation pattern of gangue particles. • The reasonable gangue particle size was determined to be 50 mm. • No damage to the storage silo was observed in the industrial test. [ABSTRACT FROM AUTHOR]

Brittleness is a key mechanical characteristic of rock and critical to various engineering practices particularly to design efficient fracturing stimulation of unconventional shale gas reservoirs. Variety of brittleness definitions and evaluation criteria have been proposed to describe rock failure behavior; however, their suitability and reliability have yet to be verified. In this paper, the existing brittleness indices were reviewed in detail and their applicability to reflect rock brittle characteristics were then investigated. The analysis indicated that most of expressions cannot describe brittle failure characteristics of rock efficiently and either partially or thoroughly fail to correctly address the impact of stress state on rock brittleness. Therefore, a new brittleness evaluation method was proposed based on promising energy transformation analysis of the complete stress-strain behavior of rock under compression. The new criterion is capable of dealing with the plastic energy dissipation mechanisms in the pre-peak region and the extent and rate to which rock strength degrades during macroscopic fracturing in the post-peak stage. Besides, the proposed brittleness index describes the entire transition of rock failure behavior of class I, from completely plastic to absolutely brittle states, in a continuous scale corresponding to 0 to 1. The applicability and outperformance of the proposed brittleness index were then verified against uniaxial and triaxial compression test results of some carbonaceous lithofacies from the Garau shale gas play within the Lurestan Basin, Iran. Samples under compression revealed various deformation and failure characteristics transitioned from brittle to semi-brittle behaviors with increasing confining pressure. Application of the brittleness indices to the tested rock specimens clearly demonstrated that the developed energy-based expression is able to rigorously capture the relative brittleness sequences of lithofacies and evolution trends under application of confinement, whereas further proved lack of either sufficient physical basis or appropriate formulation strategy in the existing indices. Accordingly, the new evaluation method seems to provide reliable estimates of rock brittleness in various field practices even though further verification is necessary. Finally, the important relation between microstructural carbonaceous texture and rock brittleness was discussed. [ABSTRACT FROM AUTHOR]

Modulating anionic oxygen in metal oxides offers exceptional opportunities for energy material synthesis via redox looping; however, several challenges such as overoxidation and catalyst deactivation need to be solved. This paper provides an overview of the state-of-the-art schemes for the selective synthesis of valuable chemicals via lattice oxygen-induced redox looping. Compared with previously published works, this review focuses on lattice oxygen modulated energy transformation technologies via chemical looping. This review discusses the chemical looping-based selective oxidation of methane to syngas/methanol, the oxidative coupling of methane, oxidative steam reforming of alcohols, and the oxidative dehydrogenation of hydrocarbons in the lattice oxygen-induced selective oxidation section. Additionally, moderate- and low-temperature Ellingham diagrams are extended to deduce the reactivity of the lattice oxygen based on thermodynamic calculation, which helps for oxygen carrier selection and product modulation. Moreover, less-researched but potential approaches to produce value-added energy materials by lattice oxygen are proposed in the perspective section, including selective oxidation of glycerol to glyceric acid, selective oxidation of methanol to acetic acid, and oxidative methane aromatization. Finally, implications for advanced oxygen carrier material design, preparation, and characterization are also overviewed. This study expands the scope of the lattice oxygen regulated energy conversion, which seeks to benefit both fundamental research and industrial applications of value-added energy material generation via lattice oxygen modulated energy transformation. [ABSTRACT FROM AUTHOR]

With regular triangular prisms of different characteristic widths as vibrators, this paper carries out the flow-induced vibration test on regular triangular prism, discusses the flow-induced vibration performance of regular triangular prism, and discloses the effect of characteristic width on vibration response and energy transformation. The test results show that the galloping of the column is divided into hard galloping and self-excited galloping. Greater characteristic width leads to higher response-amplitude ratio and lower vibration-starting velocity. In addition, increasing the characteristic width enables the regular triangular prism to gallop against higher maximum damping ratio, thereby elevating the optimal power generation damping ratio. Higher optimal power generation damping ratio in turn improves the unit capacity and energy transformation efficiency of flow-induced vibration power generators. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with the electro-mechanical transfer functions of an ultrasonic wheel system. The objective is to initiate a mode that can produce certain relative dynamic responses in the proposed ultrasonic wheel system. The performance will be parameterized by system inputs in an attempt to obtain an optimal operational configuration. The electro-mechanical transfer function model of the piezoelectric ultrasonic wheel based on the lateral elliptical motion is derived for the control application and certification of its load-characteristic parameters and also predicts the wheel system performance. On this basis, we can determine whether the output of the wheel system will be stable. The contact-dynamics behaviors of the stator are also studied. These derived formulations in this paper are based on the general concept of the constitutive laws governing piezoelectric materials which permit the introduction of kinetic energy, electrical energy, and geometric constraints relating to the deformation variables. [Copyright &y& Elsevier]

This paper deals with the transfer functions of a new disc-type ultrasonic motor: stator and stator–rotor energy transformation. The objective is to initiate a mode that can produce certain relative dynamic responses in the proposed motor. The performance will be parameterized by system inputs in an attempt to obtain an optimal operational configuration. The transfer function model of the piezoelectric ultrasonic stator based on the lateral elliptical motion is derived for the control application and certification of its load-characteristic parameters and also predicts the motor performance. On this basis, we can determine whether the output of the motor will be stable. The contact-dynamics behaviors of the stator are also studied. These derived formulations in this paper are based on the general concept of the constitutive laws governing piezoelectric materials which permit the introduction of kinetic energy, electrical energy, and geometric constraints relating to the deformation variables. [Copyright &y& Elsevier]

Slovakia committed to the objectives related to the mitigation of climate change's pace. The most important acts include reducing energy consumption and increasing the share of renewable energy in gross final energy consumption of the country. Regions are challenged by a fundamental transformation of energy. The main aim of this paper was to evaluate the use of renewable energy sources in Slovakia, as well as the procedural and economic side of support mechanisms allowing progress in the use of renewable energy sources. The secondary aim was to economically assess the impact of support schemes for the effectiveness of investments and make recommendations on renewable energy use for the next period based on an example of a biogas plant in Slovakia. Slovakia has experienced the development of biogas installations after the year 2009. By 2013, Slovak market significantly promoted investments in biogas plants, but in 2014, there was a downturn in the installation of new ones. A database for the analysis was obtained from real data of a specific biogas plant in Slovakia. Results of the analysis declare that financial support mechanisms from the country and the EU are a major determinant in the development of biogas plants in Slovakia with a positive impact on important economic indicators of effectiveness. This process will also support the achievement of the objectives of Target 2020. [ABSTRACT FROM AUTHOR]

• Effort sharing schemes and recursive dynamic CGE model were combined for economic impact and energy transformation in China under a 2 ℃ climate target. • SSP1-2.6 scenario is modified to reflect China's future energy transition strategy. • All sectors exclude service will face negative economic impacts, and national fossil energy consumption will decrease a lot. • Evaluation algorithm is developed to access effort sharing schemes in different dimensions. Pursuing 2 ℃ warming limit, as a global climate target, would not be achieved without the mitigation contribution of each country. At present, possible ranges of regional impact of 2 ℃ climate target mostly focused on multi-model simulation results lack of the comparison of multiple effort-sharing schemes. This paper presents a reginal analysis framework introduced 10 different effort-sharing schemes and SSPs-RCPs mixed scenarios, and finds out how 2 ℃ climate target affects China in economy and energy transformation and balance the trade-offs of each effort-sharing scheme. To measure how to achieve 2 ℃ climate target in China, we developed an improved recursive dynamic CGE model including carbon taxes and CCS technologies. We find that carbon budgets of 2 ℃ climate target in China under various effort-sharing schemes would be 289.8–576.7 Gt during 2010–2050, accounting for 9.5–19.0% in the world. The mitigation cost would range from 0.2% to 2.95%, and the average cost would equal GDP level in 2018. The fossil energy consumption would decrease by 17.1–57.9%, equaling the consumption level before 2010. Differentiated emission pathway with similar the carbon budget, per capita convergence (PCC) would have less economic cost than grandfathering rule. We develop an evaluation algorithm to take economy, energy and emission reduction into account, and find that PCC and ability to pay (ATP) rules would be accepted for China. [ABSTRACT FROM AUTHOR]

The present paper indicates that hydropower, including small hydropower plants (SHPs), may play a very important role in Poland's energy transformation in the near future. The development of SHPs may also increase water resources in the steppe Poland. Additionally, the aim of the present research is to conduct the PEST analysis of SHPs in Poland, taking into account the SHP potential. For the first time, maps showing the power and location of potential SHPs on the existing dams in Poland are presented. SHPs should be an important element of energy transition in Poland, especially on a local scale—it is stable energy production. Our analysis shows that there are 16,185 such dams in Poland, while the total capacity of potential hydropower plants in Poland would be 523.6 MW, and the total number of new jobs is estimated at 524. It was calculated that the annual avoided carbon dioxide emissions will amount to 4.4 million tons, which will reduce Poland's emissions by 1.4%. The construction of SHPs can bring significant environmental and economic benefits. As far as the PEST analysis is concerned, the political environment of SHPs in Poland can be described as unfavorable (2.86 points). The economical nature of PEST analysis (3.86 points) should be considered as friendly for the development of SHPs. The social nature of PEST analysis can be considered as neutral (3.36 points). The technological nature of the PEST analysis can be considered as neutral (3.21 points). [ABSTRACT FROM AUTHOR]

Due to the energy transformation in buildings, the proportions of energy consumption for heating, ventilation and domestic hot water preparation (DHW) have changed. The latter component can now play a significant role, not only in the context of the annual heat demand, but also in the context of selecting the peak power of the heat source. In this paper, the comparison of chosen methods for its calculation is presented. The results show that for contemporary residential buildings, the peak power for DHW preparation can achieve the same or higher value as the peak power for heating and ventilation. For this reason, nowadays the correct selection of the peak power of a heat source for DHW purposes becomes more important, especially if it uses renewable energy sources, because it affects its size and so the investment cost and economic efficiency. It is also indicated that in modern buildings, mainly accumulative systems with hot water storage tanks should be taken into account because they are less sensitive to design errors (wrongly selected peak value in the context of the uncertainty of hot water consumption) and because they result in acceptable value of peak power for DHW in comparison to heating and ventilation. [ABSTRACT FROM AUTHOR]

Electric traction in Poland is supplied with dc voltage which is obtained from the power grid via traction substations equipped with transformers and rectifiers. The paper gives the results of the investigation of different designs of these transformer-rectifier sets -- namely, 12- and 24-pulse systems. The comparison of electrical quantities such as ripple content, harmonic content of supply current and output voltage and utilisation of transformer secondary windings is provided. [ABSTRACT FROM AUTHOR]

Like many other countries, Germany has defined goals to reduce its CO2-emissions following the Paris Agreement of the 21st Conference of the Parties (COP). The first successes in decarbonizing the electricity sector were already achieved under the German Energiewende. However, further steps in this direction, also concerning the heat and transport sectors, have stalled. This paper describes three possible pathways for the transformation of the German energy system until 2050. The scenarios take into account current climate politics on a global, European, and German level and also include different demand projections, technological trends and resource prices. The model includes the sectors power, heat, and transportation and works on a Federal State level. For the analysis, the linear cost-optimizing Global Energy System Model (GENeSYS-MOD) is used to calculate the cost-efficient paths and technology mixes. We find that a reduction of CO2 of more than 80% in the less ambitious scenario can be welfare enhancing compared to a scenario without any climate mitigating policies. Even higher decarbonization rates of 95% are feasible and needed to comply with international climate targets, yet related to high effort in transforming the subsector of process heat. The different pathways depicted in this paper render chances and risks of transforming the German energy system under various external influences. [ABSTRACT FROM AUTHOR]

With an increasing expected energy demand and current dominance of coal electrification, India plays a major role in global carbon policies and the future low-carbon transformation. This paper explores three energy pathways for India until 2050 by applying the linear, cost-minimizing, global energy system model (GENeSYS-MOD). The benchmark scenario "limited emissions only" (LEO) is based on ambitious targets set out by the Paris Agreement. A more conservative "business as usual" (BAU) scenario is sketched out along the lines of the New Policies scenario from the International Energy Agency (IEA). On the more ambitious side, we explore the potential implications of supplying the Indian economy entirely with renewable energies with the "100% renewable energy sources" (100% RES) scenario. Overall, our results suggest that a transformation process towards a low-carbon energy system in the power, heat, and transportation sectors until 2050 is technically feasible. Solar power is likely to establish itself as the key energy source by 2050 in all scenarios, given the model's underlying emission limits and technical parameters. The paper concludes with an analysis of potential social, economic and political barriers to be overcome for the needed Indian low-carbon transformation. [ABSTRACT FROM AUTHOR]

• Effects of the position of pipe-type appendages on the FIM of a TLP are investigated experimentally. • Motion responses, drag force, and energy transformation are discussed. • At 0°-incidence of the current, the transverse and yaw motions are all mitigated and the TLP with appendages-45° is the most effective configuration. • The analysis of energy transformation indicates the development of the galloping phenomenon for the TLP with appendages-45. • The FIM can contribute to larger drag force and the increase of drag force is the most significant at 0° -incidence. Flow-induced motions (FIM) can cause fatigue damage to the mooring and riser systems of deepwater offshore structures, especially for cylindrical platforms, such as Tension Leg Platform(TLP). Previous experimental and numerical studies have showed conservative FIM prediction compared to the field measurements, due to many significant factors such as the Reynolds number, the nonuniformity of the incident current, the unsteadiness of the current velocity and platform heading, the coupled current and wave presence. Besides, the appendages covering the hull surface of platforms also played an important role in the smaller FIM responses of the field measurements. In order to specifically examine the influence of position of pipe-type appendages, this paper experimentally investigated the FIM of a TLP with different positions of appendages at 0°-incidence and compared the FIM responses, energy transformation, and average drag coefficients with those of the bare hull. An air-bearing system and a horizontal mooring system were employed to provide vertical pretension and horizontal restoring forces, respectively, and to ensure the low-friction horizontal motions. The results showed that for 0°-incidence whatever the appendages position, the transverse and yaw motions were all mitigated and the TLP with appendages-45° was the most effective configuration, with a reduction of 55% for the transverse motion and 52% for the yaw motion, mainly owing to the changes of the boundary layer separation point. However, the analysis of energy transformation indicated the development trend of the galloping phenomenon for the TLP with appendages-45°. In addition, the influence of the FIM behavior on the drag force of the TLP at 0° 22.5° and 45°-incidences was also studied. It showed that the FIM could contribute to larger drag force and the increase of drag force is the most significant at 0°-incidence, with a value of around 39%. [ABSTRACT FROM AUTHOR]

Increasing water demand for energy industries has raised concerns for the compliance of energy industry development and water resources constraints. The regional characteristics of uneven distribution of energy and water resources exacerbates regional energy-related water shortage. This paper focus on quantitative analysis of energy development impacts on water resources that considers regional characteristics. A supply-demand-integrated method is proposed to assess water stress of energy industry for multiple regions and multiple energy types under different energy development scenarios. China has a typical mismatch characteristic of energy and water resources. Case studies of China are conducted at both regional and energy-base scales. Results show that the water stress of energy industry in northwest regions (40%) is higher than that of the national average value (24%) in 2015. The carbon emission reduction measures can save the energy industrial water withdrawal by about 16%–33% in 2030, compared with the Business as Usual Scenario. Interregional power transmission would result in an over 100% value of the water stress in energy output areas. The coal chemical industry is high-water-consuming and accounts for a large proportion of the water demand in energy bases. The technological progress and capacity reduction of high-water-consuming technologies can reduce the water stress. Both water demand side and water supply side measures are suggested to reach the coordinated development of energy industry with water resources. Image 1 • Water stress of energy industry is evaluated under different development paths. • Mismatch of energy and water resources intensifies regional water stress. • Active transformation of energy structure to clean energy can reduce water stress. • Long-distance power transmission intensifies water stress in energy-rich areas. • Technological progress and capacity reduction are equally crucial for energy bases. [ABSTRACT FROM AUTHOR]

This paper is devoted to an analytical approach to the magnetoacoustic tomography with magnetic induction (MAT-MI) problem for three-layer low-conductivity objects. For each layer, we determined closed-form analytical expressions for the eddy current density and Lorentz force vectors based on the separation of variables method. Next, the analytical formulas were validated with numerical solutions obtained with the help of the finite element method (FEM). Based on the acoustic dipole radiation theory, the influence of the transducer reception pattern on MAT-MI was investigated. To obtain acoustic wave patterns, as a system transfer function we proposed the Morlet wavelet. Finally, image reconstruction examples for objects of more complex shapes are presented, and the influence of the MAT-MI scanning resolution and the presence of the noise on the image reconstruction quality was studied in detail. [ABSTRACT FROM AUTHOR]

• A generalized definition of cavitation intensity is proposed. • An approximate formula to calculate the cavitation intensity is derived. • The method to measure the cavitation intensity is discussed. Cavitation intensity has already been used to character the activity or strength of cavitation, and several methods are developed to measure the cavitation intensity. However, the previous definitions of cavitation intensity are often either vague or biased. In this paper, from the point of view of energy, the authors proposed a generalized definition of cavitation intensity, derived an approximate formula to calculate the cavitation intensity and discussed its measure method. [ABSTRACT FROM AUTHOR]

The energy transformation is changing the structure of the energy sector in Europe and Germany. In this paper the current structure of the energy sector is analysed both empirically as well as theoretically. Therefore, the authors have developed the business model framework for the energy transformation (BMFE). The framework is a synthesis of classical business model designs. An exhaustive survey of existing business models based on primary data collection and a literature review leads to 638 business models. Finally, 69 prototypical business models of the energy sector are the result of the classification of these business models. The information of the business models within the BMFE is applied to show the growing importance of value creation networks in energy industry. The work represents the current status of the business models in the energy sector. [ABSTRACT FROM AUTHOR]

The transformation of energy is an intrinsic process that is needed to trigger the internal erosion of soils subjected to a fluid flow, but how to capture this process is not understood very well. This is why this study aims to address these complex processes through a numerical fluid-particle coupling simulation. The computational fluid dynamics (CFD) is used to model fluid flows which is coupled with the discrete element method (DEM) employed to simulate soil particles. Detailed migration of particles and fluid variables are recorded to enable their kinetic energy to be computed. Successful experiments are used to demonstrate how the numerical method can be used to model the internal erosion associated with energy computation. This study shows a good agreement between the numerical and experimental results in terms of the hydraulic conductivity and erosion rate of soils subjected to upward flows. A significant loss in energy is also found as fluid flows through the soil whereas only a small amount of kinetic energy is needed to make particles migrate at a considerable degree. The influence that the porosity and uniformity of soils has on the transformation of energy is also discussed in the paper. [ABSTRACT FROM AUTHOR]

This paper presents the results of research related to the transformation of electrical energy into potential and kinetic energy of waves generated on the water surface. The waves are generated to model the environmental conditions for the needs of the model tests. The model tests are performed on model-scale objects to predict the features of full-scale maritime objects. It is done to improve human safety and the survivability of constructions. Electrical energy is transformed into the energy of the water waves using a wave maker. The wave maker considered is a facility with an electrohydraulic drive and an actuator submerged into the water. The actuator movement results in the waves being mechanically-generated in accordance with the wave maker theory. The study aimed to investigate the advantage of the newly implemented fuzzy-logic controller over the hitherto cascading proportional-integral controllers of the wave maker actuator. The research was focused on experimental investigation of the transformation process outcomes harvested under the fuzzy-logic controller, versus the cascading proportional-integral controllers. The waves were generated and measured in the real towing tank, located in the Maritime Advanced Research Centre (CTO S.A.). The investigation confirmed the advantage of the fuzzy-logic controller. It provides more accurate transformation of energy into the desired form of the water waves of specified parameters—frequency and amplitude—and more flat amplitude-frequency characteristic of the transformation process. [ABSTRACT FROM AUTHOR]