Terms Of Energy Flow Research Articles

Velocity-space Signatures of Resonant Energy Transfer between Whistler Waves and Electrons in the Earth’s Magnetosheath

Wave–particle interactions play a crucial role in transferring energy between electromagnetic fields and charged particles in space and astrophysical plasmas. Despite the prevalence of different electromagnetic waves in space, there is still a lack of understanding of fundamental aspects of wave–particle interactions, particularly in terms of energy flow and velocity-space characteristics. In this study, we combine a novel quasilinear model with observations from the Magnetospheric Multiscale mission to reveal the signatures of resonant interactions between electrons and whistler waves in magnetic holes, which are coherent structures often found in the Earth’s magnetosheath. We investigate the energy transfer rates and velocity-space characteristics associated with Landau and cyclotron resonances between electrons and slightly oblique propagating whistler waves. In the case of our observed magnetic hole, the loss of electron kinetic energy primarily contributes to the growth of whistler waves through the n = −1 cyclotron resonance, where n is the order of the resonance expansion in linear Vlasov–Maxwell theory. The excitation of whistler waves leads to a reduction of the temperature anisotropy and parallel heating of the electrons. Our study offers a new and self-consistent understanding of resonant energy transfer in turbulent plasmas.

HUMAN IMPACTS ON AQUATIC ECOSYSTEMS FROM THE LENS OF ECOLOGICAL STOICHIOMETRY

Aquatic ecosystems are under different anthropogenic pressures, such as climate change, eutrophication, chemical pollution, overfishing, and introducing exotic species. Human activities have accelerated biogeochemical cycles forcing organisms and ecosystems to adapt. Most ecological stoichiometry studies are focused on carbon, nitrogen, phosphorus, and their relative proportions. Still, the possibilities for investigations using other elements to better understand the impacts of human pressures on aquatic ecosystems are vast. Therefore, here we explore how different anthropogenic activities influence ecosystem balance in terms of nutrient composition and stoichiometry. We conclude that human interventions have affected the functioning of aquatic ecosystems in terms of energy flow due to stoichiometric imbalances. We also conclude that the interplay between macro and micronutrient stoichiometry might raise important axioms to predict and understand human impacts on the functioning of aquatic ecosystems.

Does fish growth respond to fishing restrictions within Marine Protected Areas? A case study of the striped red mullet in the south‐west Adriatic Sea (central Mediterranean)

Abstract Some of the factors that influence fish growth are intrinsic (e.g. genetic and physiological), while others are environmentally driven (e.g. temperature, food availability). Growth, therefore, has biological but also ecological implications, as it is influenced by the environment in terms of energy flow. In this study, the growth patterns of the striped red mullet, Mullus surmuletus, inside the buffer zone of the Marine Protected Area (MPA) of Torre Guaceto and in two locations (Monopoli and Molfetta) outside the MPA were investigated in the south Adriatic Sea (central Mediterranean). The growth parameters for the female population fraction were estimated using the otolith back‐calculation technique: predicted asymptotic length (infinity) (TL∞) = 313.781 mm, growth coefficient (K) = 0.236 year−1 and prenatal length (t0) = −1.255 year for Molfetta; TL∞ = 342.988 mm, K = 0.173 year−1 and t0 = −1.828 year for Monopoli; TL∞ = 404.394 mm, K = 0.199 year−1 and t0 = −1.037 year for Torre Guaceto MPA. The results showed a significantly higher growth rate of female specimens of M. surmuletus, particularly 2 years and older, obtained from inside the MPA compared to those taken at the two outside locations. These findings suggest that fishing restrictions in the buffer zone of the MPA (where fish are more abundant and bigger) could be a more powerful driver for boosting individual fish growth than the mere ‘density effect’, which would have suggested lower growth rates associated with higher population densities.

Frequency splitting approach using wavelet for energy management strategies in fuel cell ultra-capacitor hybrid system

Using frequency splitting, two energy management strategies (EMS) based on Haar wavelet decomposition and Fourier analysis for fuel cell hybrid vehicle (FCHV) are proposed to manage efficiently the power flow between components. The paper aims to discuss the performances of the proposed EMS in terms of dynamic behavior, robustness operation, real time application and fuel economy. For apply this methodology, two EMS approaches are elaborated and successfully tested for parallel Fuel Cell/UC: conventional approach using Fourier Transform analysis (FT) and Wavelet analysis approach allowing natural frequency splitting. Finally, and to evaluate the performance and relevance of the developed approach, a comparison analysis were conducted. The simulation results exhibit the effectiveness of both strategies. Indeed, Wavelet analysis leads to better results in terms of energy flow and dynamic behavior, excellent robustness and stability of system, as well as energy economy improvement. A very relevant strategy is proposed based on Wavelet analysis using digital filtering techniques, which enables a natural frequency splitting to ensure the best global performances. In addition, the approach remains simple and suitable for real time operation.

The microbial contribution to the trophic position of stomiiform fishes

Abstract The trophic position (TP) of fishes determines their importance in terms of energy flows within food webs. However, accurate estimations of TP are often prevented because of the difficulties in tracing all food sources. This is particularly challenging for omnivorous fishes, such as those from the Order Stomiiformes. In this study, we applied recent developments in stable isotope analysis of amino acids to untangle the contributions of microbial vs. metazoan food webs in 13 species of Stomiiformes. The inclusion of the microbial food web reduced the differences between TP estimates using stable isotopes and those derived from stomach content analysis. In addition, the new estimates allowed to quantify the relative contribution of the microbial food web to each species (6–21%), highlighting the importance of detritus consumption even in piscivorous species (e.g. Stomias boa and Chauliodus danae). The comparison of TP estimates obtained with selected amino acids in fish muscle allowed for the detection of the microbial influence integrated at time scales relevant for net fish growth, even when trophic exchanges in the microbial food web occur at much shorter time scales. The assessment of TP considering the differential contribution of microbial and metazoan food webs challenges our current understanding of marine food webs; yet provides a new quantitative tool for the analysis of their structure and function.

Productivity of the crop rotation link with lupine with different methods of basic tillage

The current paper has considered the study results of the productivity of the lupine-winter wheat rotation link with different methods of basic tillage. The study was carried out on grey forest soil in the south-west of the Blackearth part of the Bryansk region on the basis of the stationary trial of the All-Russian Research Institute of Lupine in 2015–2018. The purpose of the study was to characterize the productivity of the lupine – winter wheat crop rotation link with differ[1]ent methods of basic tillage. The scheme of the trial included four variants of the main tillage during the cultivation of winter wheat and lupine in a four crop rotation sequences, namely winter wheat – naked oats – winter triticale – lupine. During the period of the study, the highest productivity of the lupine-winter wheat rotation link was identified in the case of moldboard plowing with chisel tillage once every four years for lupine and amounted to 5.2 t/ha of grain units. With this method of tillage, winter wheat and lupine showed high rates of yield and nutritional value. These indicators turned out to be energetically beneficial in terms of energy flow in the agroecosystem. The lowest rates of yield of the link was obtained in the option with subsurface plowing to a depth of 16 cm and amounted to 3.9 t/ha of grain units; the energy cost per ton of grain was 6.7 GJ. With the option with traditional moldboard plowing, the productivity of the crop rotation link was 4.5 t/ha of grain units, and the energy cost was 5.9 GJ per ton of grain. All the presented options of the main tillage in this crop rotation can be used on farms with different levels of economic development and farming culture.

A techno-economic evaluation of the impact of electric vehicles diffusion on Italian customer billing tariffs

The sales of electric vehicles (EV) are recently experiencing an exponential growth. There is scientific evidence that EVs, in their lifecycle, generate a lower amount of greenhouse gases emissions and local pollution with respect to ICE ones. However, a fast EVs diffusion will increase the load on the power system in a still unclear manner. It is recognized that EV charging is a power intensive operation and that dumb charging strategies will increase security problems for grid management. This will likely happen at the end of business, when a huge quantity of EVs gets connected at the domestic socket at the same time, thus contributing to the ramp up needs from thermal generators to cope with the increasing slope in the “duck curve” at sunset. The presented model estimates the burden that different EV penetration scenarios will have on Italian power system in a short term (2025). This is evaluated in terms of energy flows and load profiles for the charging operations. A behavioural analysis of EV charging operations and a thorough investigation of Italian electricity tariff allows to calculate the economic impact of a base and a strategically regulated scenario. In the regulated scenario, featuring a regulatory toolbox to steer EVs diffusion efficiently, the impact on the power system is mitigated even in case of a larger EV penetration.

Using requirement-functional-logical-physical models to support early assembly process planning for complex aircraft systems integration

The assembly line process planning connects product design and manufacturing through translating design information to assembly integration sequence. The assembly integration sequence defines the aircraft system components installation and test precedence of an assembly process. This activity is part of the complex systems integration and verification process from a systems engineering view. In this paper, the complexity of modern aircraft is defined by classifying aircraft system interactions in terms of energy flow, information data, control signals and physical connections. At the early conceptual design phase of assembly line planning, the priority task is to understand these product complexities, and generate the installation and test sequence that satisfies the designed system function and meet design requirements. This research proposes a novel method for initial assembly process planning that accounts for both physical and functional integrations. The method defines aircraft system interactions by using systems engineering concepts based on traceable RFLP (Requirement, Functional, Logical and Physical) models and generate the assembly integration sequence through a structured approach. The proposed method is implemented in an industrial software environment, and tested in a case study. The result shows the feasibility and potential benefits of the proposed method.

Benthic Diatoms of the Ying River (Huaihe River Basin, China) and Their Application in Water Trophic Status Assessment

Benthic diatoms are an indispensable link of the water ecological system in terms of energy flow and material cycling, and they directly or indirectly reflect the status of the water environment. We sampled benthic diatoms and environmental factors from April to May of 2013 from 53 sites along the Ying River to study their application in local water trophic status assessment, with a focus on the dominant benthic diatom species, their composition and distribution pattern, and the relationship between benthic diatoms and environmental factors. A total of 370 species and varieties were identified, belonging to 56 genera and six orders. The dominant species were as follows: Nitzschia inconspicua Grunow, Achnanthidium minutissimum (Kützing) Czarnecki, Navicula aitchelbee L. L. Bahls, Nitzschia palea (Kützing) Smith, Cyclotella meneghiniana Kützing, Navicula submuralis Hustedt and Mayamaea atomus (Kützing) Lange-Bertalot. The Ying River was divided into five orders using the Strahler method and three regions according to total nitrogen, total phosphorus and ammonia nitrogen. In region Y-1, which had the lowest nutrient level, the dominant species was Achnanthidium minutissimum. In region Y-2, which had the highest nutrient level, Navicula aitchelbee, Nitzschia palea, and Cyclotella meneghiniana were dominant, while in region Y-3, which had moderate nutrient levels, Nitzschia inconspicua was dominant. Pearson’s correlation analysis and canonical correspondence analysis (CCA) revealed a significant correlation between the environmental factors with dominant species and diatom indices (especially the SPI). Our study indicates that dominant species and diatom indices can, to some extent, indicate the environment, especially nutrient distribution.

Experimental structure-borne energy flow contribution analysis for vibro-acoustic source ranking

Abstract Noise legislations and the increasing customer demands determine the NVH (Noise Vibration and Harshness) development of modern commercial vehicles. In order to meet the stringent legislative requirements for the vehicle noise emission, exact knowledge of all vehicle noise sources and their acoustic behavior is required. The development of new analysis tools to investigate the vibroacoustic behaviour within vehicle development process is of essential importance to achieve better products in combination with time and cost reduction. This paper discusses the application of an experimental multi-point and multi-DOF energy flow analysis (EFA) methodology for the NVH assessment and ranking of vibro-acoustic sources. The methodology consists of two steps in which the system mobility matrix are obtained by direct measurements whereas the dynamic loads under operational conditions are obtained through an inverse procedure. A finite difference technique is used to distinguish between degrees of freedom. A practical example is given for a gearbox, for which the noise paths from the gears through the gear-supporting shafts and bearings into the gearbox housing has been experimentally assessed in terms of energy flows. This paper also discusses the accuracy and limits of the methodology.

The Energy Structure of the Canadian Economy

SummaryWe developed a model of a national economy in which the phenomena of supply, demand, economic growth, and international trade are represented in terms of energy flows. In examining the structure of the economy, we distinguish between the energy embodied in capital assets used in the production and distribution of energy and that embodied in capital assets and goods that consume energy. Sources used to quantify the energy flows include: end‐use energy data by economic sector; International Energy Agency–style national energy balances, and national input‐output tables. As an example, the Canadian economy for 2008 produced 16.97 exajoules (EJ) of energy, which after net export of 6.16 EJ and other adjustments left a total primary energy consumption of 10.61 EJ. The energy supply and distribution sectors used close to 32% (3.36 EJ) of total primary consumption. Analysis of primary energy consumption shows that 25.14% was embodied in household consumption, 22.85% was consumed directly by households, 7.88% was embodied in government services, and 34.07% was embodied in exports. Of significance to economic growth, 7.14% was embodied in capital in energy demanding sectors, 1.25% in energy consuming personal assets, and 1.52% in supply sector capital. The energy return on energy investment was relatively constant, averaging 5.14 between 1990 and 2008. Capital investments required to decouple the Canadian economy from its dependence on fossil fuels are discerned.

An assessement of global energy resource economic potentials

This paper presents an assessment of global economic energy potentials for all major natural energy resources. This work is based on both an extensive literature review and calculations using natural resource assessment data. Economic potentials are presented in the form of cost-supply curves, in terms of energy flows for renewable energy sources, or fixed amounts for fossil and nuclear resources, with strong emphasis on uncertainty, using a consistent methodology that allow direct comparisons to be made. In order to interpolate through available resource assessment data and associated uncertainty, a theoretical framework and a computational methodology are given based on statistical properties of different types of resources, justified empirically by the data, and used throughout. This work aims to provide a global database for natural energy resources ready to integrate into models of energy systems, enabling to introduce at the same time uncertainty over natural resource assessments. The supplementary material provides theoretical details and tables of data and parameters that enable this extensive database to be adapted to a variety of energy systems modelling frameworks.

Integrative trophic network assessments of a lentic ecosystem by key ecological approaches of water chemistry, trophic guilds, and ecosystem health assessments along with an ECOPATH model

The objective of this study was to describe the trophic structure and energy flow in a lentic ecosystem in South Korea. Physicochemical water conditions were evaluated along with the reservoir ecosystem health using a multimetric IBI model. Nutrient analyses of the reservoir showed a nutrient rich and hypereutrophic system. Guild analysis revealed that tolerant and omnivorous species dominated the ecosystem. Tolerant fish, as a proportion of the number of individuals, were associated ( R 2 > 0.90, p < 0.01) with TN and TP, the key indicators of trophic state in lentic ecosystems. The mean Reservoir Ecosystem Health Assessment (REHA) score was 19.3 during the study, which was judged as in ‘fair to poor’ condition. A trophic analysis of the reservoir estimated by the ECOPATH model shows that most activity in terms of energy flow occurred in the lower part of the trophic web, where there was intensive use of primary producers as a food source. Consequently, of the 10 consumer groups, nine fell within trophic levels <2.8. Trophic levels (TL) estimated from the weighted average of prey trophic levels varied from 1.0 for phytoplankton, macrophytes, and detritus to 3.25 for the top predator, Pseudobagrus fulvidraco. Our integrated approach to trophic network analysis may provide a key tool for determining the effects of nutrient influx on energy flow pathways in lentic ecosystems.

Seven Transmembrane Receptors as Shapeshifting Proteins: The Impact of Allosteric Modulation and Functional Selectivity on New Drug Discovery

It is useful to consider seven transmembrane receptors (7TMRs) as disordered proteins able to allosterically respond to a number of binding partners. Considering 7TMRs as allosteric systems, affinity and efficacy can be thought of in terms of energy flow between a modulator, conduit (the receptor protein), and a number of guests. These guests can be other molecules, receptors, membrane-bound proteins, or signaling proteins in the cytosol. These vectorial flows of energy can yield standard canonical guest allostery (allosteric modification of drug effect), effects along the plane of the cell membrane (receptor oligomerization), or effects directed into the cytosol (differential signaling as functional selectivity). This review discusses these apparently diverse pharmacological effects in terms of molecular dynamics and protein ensemble theory, which tends to unify 7TMR behavior toward cells. Special consideration will be given to functional selectivity (biased agonism and biased antagonism) in terms of mechanism of action and potential therapeutic application. The explosion of technology that has enabled observation of diverse 7TMR behavior has also shown how drugs can have multiple (pluridimensional) efficacies and how this can cause paradoxical drug classification and nomenclatures.

Food Webs for Parasitologists: A Review

This review examines the historical origins of food web theory and explores the reasons why parasites have traditionally been left out of food web studies. Current paradigms may still be an impediment because, despite several attempts, it remains virtually impossible to retrofit parasites into food web theory in any satisfactory manner. It seems clear that parasitologists must return to first principles to solve how best to incorporate parasites into ecological food webs, and a first step in changing paradigms will be to include parasites in the classic ecological patterns that inform food web theory. The limitations of current food web models are discussed with respect to their logistic exclusion of parasites, and the traditional matrix approach in food web studies is critically examined. The well-known energetic perspective on ecosystem organization is presented as a viable alternative to the matrix approach because it provides an intellectually powerful theoretical paradigm for generating testable hypotheses on true food web structure. This review proposes that to make significant contributions to the food web debate, parasitologists must work from the standpoint of natural history to elucidate patterns of biomass, species abundance, and interaction strengths in real food webs, and these will provide the basis for more realistic models that incorporate parasite dynamics into the overall functional dynamics of the whole web. A general conclusion is that only by quantifying the effects of parasites in terms of energy flows (or biomass) will we be able to correctly place parasites into food webs.

Dynamic Instabilities of Simulated Hurricane-like Vortices and Their Impacts on the Core Structure of Hurricanes. Part II: Moist Experiments

Abstract The energy flows of a simulated moist hurricane-like vortex are analyzed to examine the processes that change the intensity and structure of tropical cyclones. The moist vortex used in this study is initially axisymmetric on an f plane and is placed on a uniform surface—an ocean with constant sea surface temperature of 29°C. Two simulations are performed using the following different environmental flows: one in a calm environment and the other in weak environmental vertical shear. The differences between the intensities and structures of the two simulated vortices are discussed in terms of energy flows. While the structure and intensity of the vortex without shear are relatively steady, those of the vortex with shear experience dramatic changes. The sheared vortex shows delayed weakening, persistent wavenumber 1 asymmetry with maximum rainfall on the downshear left side, and top-down breakdown. In both vortices barotropic energy conversion is stronger than baroclinic energy conversion. However, baroclinic processes in the upper levels of the sheared vortex play an important role in weakening the vortex. The energy flow diagram and the cross section of energy conversion terms show the existence of multiple baroclinic eddy life cycles at the upper levels of the sheared vortex. The activity of the baroclinic eddies continues until ventilation of the upper-level warm-core structure is sufficient to weaken the sheared vortex.

Information indices as a tool for quantifying development of below-ground terrestrial ecosystems

Information indices from ecosystem network analysis (ENA) describe the size and organization of an ecosystem and are claimed to quantify ecosystem development [Ulanowicz, R.E., 1986, Growth and Development, Springler-Verslag, New York, 203 pp.]. To date, these indices were not used to describe a gradient of ecosystem development for a field situation. Here we used information indices to quantify soil succession with soils of different age on the island Schiermonnikoog, The Netherlands. We evaluated whether information indices describe ecosystem development as predicted by ENA. For the Island of Schiermonnikoog the biomasses of soil organisms and roots were measured on four stages of succession (0, 10, 25 and 100 years old soils). Organisms were grouped based on their feeding characteristics. With these data consumption, respiration, excretion, external input and output flows to, from and between groups were calculated. These flows, in turn, were used to calculate the information indices. Relative information indices describe the organization of an ecosystem; i.e. level of organisation (specialization of flows), diversity and evenness of flows, and disorganisation. Absolute indices describe both size (in terms of energy flow) and organisation of the system. System size is used to scale the absolute indices and will be analysed separately as well. We found that the absolute indices increased when succession processed, as predicted by theory. This pattern could have been due to the build-up of biomass, which apparently did not level off. Because the succession gradient deals mostly with young soils (0, 10 and 25 years old) and only one older field (100 years old), the gradient should include more soils of around 100 years old and older to exclude this possibility. Relative indices, on the other hand, increased initially, but then levelled off. We think that this was due to the strong aggregation of functional groups, especially at lower trophic levels, because information in some functional groups showed (expected) trends. Our results suggest that the absolute indices are able to describe ecological succession of terrestrial below-ground ecosystems. The relative indices, in contrast, appeared to be insensitive to subtle succesional changes.

Layered Microbial Communities and the Search for Life in the Universe

Searching for life when we do not know what it is like is at best a difficult task, and at worst, an exercise fraught with frustration and potential failure. In developing methods that will have general applicability, one must ascertain first what the general features of life might be that, when present, would provide strong inference of the presence of active life. We propose here that the tendency of life to be associated with energetic gradients, in fact to create its own gradients via the catalytic consumption of nutrients and oxidants, and the production of waste products, is one of the general features of active extant life. As life seeks out and creates such gradients, layered microbial communities, or LMCs, result that are in their own way, prima facie biosignatures. These LMCs are abundant, perhaps ubiquitous in physically stratified environments on our own planet. If energy flows through a given system, and if life has developed efficient catalytic methods to utilize this energy, then LMCs are predicted to be present. Here we discuss the general issues of what can be gleaned from the study of LMCs in terms of energy flow, carbon flow, and carbon storage in earthly ecosystems, as well as the philosophy of using LMCs as biosignatures in the search for life on Earth, and perhaps, in extraterrestrial sites.

Energy flow and fluorescence near a small metal particle

We examine the classical energy-balance equation for a fluorescing system consisting of a molecule near a small, spherical metal particle capable of sustaining electromagnetic resonances and irradiated with laser light. From the energy-flow distribution in the entire system, we obtain the enhancement factor for the fluorescence emission of the adsorbed molecule. Numerical results demonstrate that the electromagnetic interactions of the molecule and the surface can be understood in terms of energy flow through the entire system and applied to investigate spectroscopic properties of adsorbates in similar systems. Absorption and emission rates of the adsorbed molecule are determined considering the energy-flow distribution and its dependence on the substrate as well as molecular parameters. Such understanding is useful in predicting spectroscopic responses of adsorbates.

Intra- and interspecies comparison of energy flow in North Atlantic flatfish species by means of dynamic energy budgets

The quantitative aspects of growth and reproduction in four flatfish species (plaice, flounder, dab, sole) in terms of energy flow are described on the basis of a dynamic energy budget (DEB theory). This theory consists of general assumptions about energy uptake, storage and utilisation and describes an individual by two state variables: structure and reserve, whereby body size exerts its influence through the ratio between surface area and volume. Comparison between model estimates and field data shows that the DEB model successfully describes the energetics of growth and reproduction in a number of flatfish species. Differences between species could be captured in the same model using different parameter values. Intraspecific differences in growth between males and females are mainly caused by differences in maximum surface area-specific ingestion rates. Differences between species are reflected in the surface area-specific maximum ingestion rate, the energy partitioning over growth and reproduction, and in egg volume. According to these parameters at 283 K (10°C), the species could be ranked as follows: surface area-specific maximum ingestion rate (W m −2) plaice: 56.6; flounder: 54.5; sole: 45.1 and dab: 36.1 W m −2. Fraction of energy allocated to reproduction (–): flounder: 0.35; plaice: 0.15; dab: 0.15 and sole 0.10. As a consequence of these differences in surface area-specific maximum ingestion rate and in the fraction of utilised energy allocated to reproduction, the gonad masses (g) of females of 0.5 kg wet mass differ considerably: flounder: 149 g; plaice: 86 g; sole: 70 g; and dab: 69 g. However, due to differences in egg size between species, the potential annual egg production shows a completely different pattern: dab: 2200 10 3; flounder: 1560 10 3; sole: 343 10 3 and plaice: 130 10 3 eggs.