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Kovac, Helmut, Anton Stabentheiner y Robert Brodschneider. "Foraging strategy of wasps – optimisation of intake rate or energetic efficiency?" Journal of Experimental Biology 221, n.º 14 (29 de mayo de 2018): jeb174169. http://dx.doi.org/10.1242/jeb.174169.
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Takács, István y Katalin Takács-György. "Arguments for the optimisation of using biomass for energy production". Applied Studies in Agribusiness and Commerce 7, n.º 2-3 (30 de septiembre de 2013): 103–8. http://dx.doi.org/10.19041/apstract/2013/2-3/17.
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Using biomass to produce energy is not a new idea. In the past, the by-products of energy(?) production processes or naturally grown materials were mainly used for energy production. At the same time, during the production of biomass the conventional sources of energy are used (fuels, the embodied energy of which is used in the production of the biomass and equipment, etc.) which must be taken into account when determining the net energy production. This research aims to examine how to optimise the production and use of biomass energy and its supply chain in the energetic and economic criteria system, as well as how to impact upon the managing models of the processes to the energetic and economic parameters of the supply chain; we ask what criteria characterise the natural (environmental), economic and social sustainability, and how they can be implemented e.g. within the framework of an innovation cluster. This article describes a test model, and analyses the results of the model examinations and the conditions for compliance with sustainability criteria. Arguing the environmental, economic and social sustainability among the criteria of the model for evaluation is not possible at all times by means of direct indicators. The results of the research proved that only multi-criteria optimisation models serve a proper decision-making instrument for the evaluation of biomass utilisation for energy production.
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Mason, I. G. y A. J. V. Miller. "Energetic and economic optimisation of islanded household-scale photovoltaic-plus-battery systems". Renewable Energy 96 (octubre de 2016): 559–73. http://dx.doi.org/10.1016/j.renene.2016.03.048.
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Ferrari, G., K. Górczyńska, R. Mimmo, C. De Lazzari, F. Clemente, G. Tosti y M. Guaragno. "Mono and Bi-ventricular Assistance: Their Effect on Ventricular Energetics". International Journal of Artificial Organs 24, n.º 6 (junio de 2001): 380–91. http://dx.doi.org/10.1177/039139880102400603.
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When mono- and bi-ventricular mechanical assistance is used for heart recovery, its control strategy and circulatory variables affect ventricular energetics (external work-EW, oxygen consumption-VO2, cardiac mechanical efficiency-CME). This study is based on the data obtained in vitro and presents an analysis of the effects of the mono- and bi-ventricular mechanical assistance on ventricular energetics. The assistance was conducted on the principle of counterpulsation with atrio-arterial connection. It includes the following stages: 1) the characterisation of the isolated ventricle model in terms of EW, VO2 and CME as a function of the filling pressure and peripheral resistance, 2) modelling of left ventricular and pulmonary dysfunction, followed by left ventricular and bi-ventricular assistance. Experimental data enable us to draw the following conclusions: • in general, the greatest hemodynamic improvement does not correspond to the highest energetic improvement, • LVAD assistance deteriorates left ventricular CME while its effect on right ventricular energetics depends on the value of right ventricular elastance (Emax). Right ventricular CME is deteriorated by BVAD assistance irrespective of right Emax, • the energetics optimisation in bi-ventricular assistance is closely related to the right Emax, which could probably be a deciding factor in the choice of the assistance mode.
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Ogunwa, Titilayo, Blake McIvor, Nurkhairunisa Awang Jumat, Ermira Abdullah y Javaan Chahl. "Longitudinal Actuated Abdomen Control for Energy Efficient Flight of Insects". Energies 13, n.º 20 (20 de octubre de 2020): 5480. http://dx.doi.org/10.3390/en13205480.
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The actuated abdomens of insects such as dragonflies have long been suggested to play a role in optimisation and control of flight. We have examined the effect of this type of actuation in the simplified case of a small fixed wing aircraft to determine whether energetic advantages exist in normal flight when compared to the cost of actuation using aerodynamic control surfaces. We explore the benefits the abdomen/tail might provide to balance level flight against trim changes. We also consider the transient advantage of using alternative longitudinal control effectors in a pull up flight maneuver. Results show that the articulated abdomen significantly reduces energy consumption and increase performance in isolated manoeuvres. The results also indicate a design feature that could be incorporated into small unmanned aircraft under particular circumstances. We aim to highlight behaviours that would increase flight efficiency to inform designers of micro aerial vehicles and to aid the analysis of insect flight behaviour and energetics.
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Vlaswinkel, E. E. "Energetic analysis and optimisation of an integrated coal gasification-combined cycle power plant". Fuel Processing Technology 32, n.º 1-2 (noviembre de 1992): 47–67. http://dx.doi.org/10.1016/0378-3820(92)90006-c.
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Marunich, N. A., B. I. Kochurov y V. V. Kizima. "Geo-Energetic Assessment and Optimisation of Emergent Effects of the Natural-Anthropogenic Landscape". Вестник ВГУ Серия География Геоэкология, n.º 3 (2022): 52–56. http://dx.doi.org/10.17308/geo/1609-0683/2022/3/52-56.
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Susantez, Çiğdem y Aldélio Bueno Caldeira. "Genetic Algorithm Optimisation of a TNT Solidification Model". Defence Science Journal 69, n.º 6 (16 de diciembre de 2019): 545–49. http://dx.doi.org/10.14429/dsj.69.14037.
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The control of the solidification process of energetic materials is important to prevent manufacturing defects in high explosive ammunitions. The present work aims to propose an optimisation procedure to determine the value of the model parameter, avoiding the traditional trial and error approach. In this work, the solidification of TNT has been numerically modelled employing apparent heat capacity method and the model parameter was optimised using genetic algorithm. One dimensional numerical model has been solved in Comsol Multiphysics Modeling Software and the genetic algorithm code was written in Matlab. The Neumann’s analytical solution of the solidification front was used as a reference to build the fitness function, following the inverse problems concepts. The optimum model parameter has been predicted after 20 generations and among 30 candidate solutions for each generation. The numerical solution performed with the optimised model parameter has agreed with the analytical solution, indicating the feasibility of the proposed procedure. The discrepancy was 3.8 per cent when maximum difference between analytical and numerical solutions was observed.
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Fani, Maryam, Aliasghar Mozafari y Bijan Farhanieh. "Evolutionary algorithm for reversed iterative optimisation method accuracy inspection applied for energetic and economic optimisation of a pulp and paper mill". International Journal of Exergy 7, n.º 3 (2010): 311. http://dx.doi.org/10.1504/ijex.2010.031987.
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Stabentheiner, Anton y Helmut Kovac. "Energetic Optimisation of Foraging Honeybees: Flexible Change of Strategies in Response to Environmental Challenges". PLoS ONE 9, n.º 8 (27 de agosto de 2014): e105432. http://dx.doi.org/10.1371/journal.pone.0105432.
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Jiggens, Piers, Daniel Heynderickx, Ingmar Sandberg, Pete Truscott, Osku Raukunen y Rami Vainio. "Updated Model of the Solar Energetic Proton Environment in Space". Journal of Space Weather and Space Climate 8 (2018): A31. http://dx.doi.org/10.1051/swsc/2018010.
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The Solar Accumulated and Peak Proton and Heavy Ion Radiation Environment (SAPPHIRE) model provides environment specification outputs for all aspects of the Solar Energetic Particle (SEP) environment. The model is based upon a thoroughly cleaned and carefully processed data set. Herein the evolution of the solar proton model is discussed with comparisons to other models and data. This paper discusses the construction of the underlying data set, the modelling methodology, optimisation of fitted flux distributions and extrapolation of model outputs to cover a range of proton energies from 0.1 MeV to 1 GeV. The model provides outputs in terms of mission cumulative fluence, maximum event fluence and peak flux for both solar maximum and solar minimum periods. A new method for describing maximum event fluence and peak flux outputs in terms of 1-in-x-year SPEs is also described. SAPPHIRE proton model outputs are compared with previous models including CREME96, ESP-PSYCHIC and the JPL model. Low energy outputs are compared to SEP data from ACE/EPAM whilst high energy outputs are compared to a new model based on GLEs detected by Neutron Monitors (NMs).
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Ardigo, M. R., Valérie Parry, I. Popa, Sébastien Chevalier, Walairat Chandra-Ambhorn, P. Phakpeetinan y Yves Wouters. "Optimisation of Metallic Interconnects for Hydrogen Production by High Temperature Water Vapour Electrolysis". Defect and Diffusion Forum 323-325 (abril de 2012): 239–44. http://dx.doi.org/10.4028/www.scientific.net/ddf.323-325.239.
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For economical and environmental reasons, hydrogen is considered as a major energetic vector for the future. Hydrogen production via high temperature water vapour electrolysis (HTE) is a promising technology. A major technical difficulty related to high temperature water vapour electrolysis is the development of interconnects working efficiently for a long period. Working temperature of 800°C enables the use of metallic materials as interconnects. Chromia forming alloys are among the best candidates. The interconnect material chosen in the present study is a ferritic stainless steel with 18% chromium content. High temperature corrosion resistance and electrical conductivity of the alloy was tested in both cathode (H2/H2O) and anode (O2/H2O) atmospheres. Corrosion products were then characterized by SEM-EDX and XRD. Moreover chromium evaporation measurements were carried out under anode atmosphere.
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Studd, E. K., A. K. Menzies, E. R. Siracusa, B. Dantzer, J. E. Lane, A. G. McAdam, S. Boutin y M. M. Humphries. "Optimisation of energetic and reproductive gains explains behavioural responses to environmental variation across seasons and years". Ecology Letters 23, n.º 5 (mayo de 2020): 841–50. http://dx.doi.org/10.1111/ele.13494.
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Foures, D. P. G., C. P. Caulfield y P. J. Schmid. "Optimal mixing in two-dimensional plane Poiseuille flow at finite Péclet number". Journal of Fluid Mechanics 748 (28 de abril de 2014): 241–77. http://dx.doi.org/10.1017/jfm.2014.182.
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AbstractWe consider the nonlinear optimisation of the mixing of a passive scalar, initially arranged in two layers, in a two-dimensional plane Poiseuille flow at finite Reynolds and Péclet numbers, below the linear instability threshold. We use a nonlinear-adjoint-looping approach to identify optimal perturbations leading to maximum time-averaged energy as well as maximum mixing in a freely evolving flow, measured through the minimisation of either the passive scalar variance or the so-called mix-norm, as defined by Mathew, Mezić & Petzold (Physica D, vol. 211, 2005, pp. 23–46). We show that energy optimisation appears to lead to very weak mixing of the scalar field whereas the optimal mixing initial perturbations, despite being less energetic, are able to homogenise the scalar field very effectively. For sufficiently long time horizons, minimising the mix-norm identifies optimal initial perturbations which are very similar to those which minimise scalar variance, demonstrating that minimisation of the mix-norm is an excellent proxy for effective mixing in this finite-Péclet-number bounded flow. By analysing the time evolution from initial perturbations of several optimal mixing solutions, we demonstrate that our optimisation method can identify the dominant underlying mixing mechanism, which appears to be classical Taylor dispersion, i.e. shear-augmented diffusion. The optimal mixing proceeds in three stages. First, the optimal mixing perturbation, energised through transient amplitude growth, transports the scalar field across the channel width. In a second stage, the mean flow shear acts to disperse the scalar distribution leading to enhanced diffusion. In a final third stage, linear relaxation diffusion is observed. We also demonstrate the usefulness of the developed variational framework in a more realistic control case: mixing optimisation by prescribed streamwise velocity boundary conditions.
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Szewczyk, Roman y Dorota Jackiewicz. "The Application of the Extended Jiles-Atherton Model for Simulating the Magnetic Characteristics of X30CR13 Steel". Solid State Phenomena 220-221 (enero de 2015): 725–30. http://dx.doi.org/10.4028/www.scientific.net/ssp.220-221.725.
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The application of magnetic-property oriented methods for non-destructive testing is very promising due to its low cost and robustness. This paper presents the methodology of simulating the magnetic properties of martensitic X30Cr13 steel applying the extended Jiles-Atherton model. On the basis of experimental measurements, the parameters of the Jiles-Atherton model were determined by an evolutionary strategy together with gradient optimisation. A very good agreement between experimental hysteresis loops and the model was confirmed by a high value of determination coefficient. The presented results open new possibilities of developing methods for non-destructive testing of energetic turbines made of X30Cr13 stainless steel. Moreover, quantitative simulation gives a possibility of a better understanding of magnetisation processes.
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Paluszczyszyn, Daniel, Piotr Skworcow y Bogumil Ulanicki. "Online simplification of water distribution network models for optimal scheduling". Journal of Hydroinformatics 15, n.º 3 (3 de enero de 2013): 652–65. http://dx.doi.org/10.2166/hydro.2013.029.
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This paper presents an implementation of an extended simplification algorithm of water distribution network models for the purpose of inclusion in the online optimisation strategy for energy and leakage management in water distribution systems. Whereas the previously proposed reduced model represented accurately the original hydraulic water network characteristics, the energy distribution in the simplified model was not preserved. This could cause a situation where the pump speed required to satisfy specified minimum pressure constraints is different for the reduced model and the original model. This problem has been identified, and an appropriate modification to the simplification algorithm has been introduced. The idea comprises introduction of the energy audit of the water network and the calculation of new minimum service pressure constraints for the simplified model. The approach allows the preservation of both hydraulic and energetic characteristics of the original water network and therefore meets the requirements of the online optimisation strategy. Suitability of the proposed approach is evaluated via a case study. The modern parallel programming implementation allowed water network models consisting of several thousand elements to be reduced within 2 min with an average relative accuracy of less than 2% in terms of tanks flows.
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Imbernon, J. A., X. Aldea, B. Usquin y D. Marin. "Auditing and monitoring to enhance energy efficiency (AGBAR experience)". Water Practice and Technology 9, n.º 3 (1 de septiembre de 2014): 277–82. http://dx.doi.org/10.2166/wpt.2014.015.
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The changing global energy environment which promotes efficiency in energy use and production as well as the use of renewable energies has led to the need for appropriate methodologies and tools in order to manage energy more efficiently. The objective of this paper is to describe the methodology and tools developed and implemented by Aqualogy (a subsidiary company of the AGBAR water utility company, specialised in technology) in order to improve energetic performance and reduce carbon dioxide (CO2) emissions from water facilities. The methodology combines energy auditing with an energy consumption monitoring plan. Some tools have been developed in this field in order to support decision-making, such as those regarding tariff optimisation, and prediction of equipment anomalies that could lead to an increase in energy consumption. Using the tool CAFCA, a carbon footprint calculator specifically for the water cycle, it is possible to report greenhouse gases emissions and to quantify savings in CO2 emissions. By applying this methodology to 21.7% of AGBAR's facilities we have been able to observe a reduction of 3% audited energy, which means 6% of the facilities' energetic cost.
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Martinaitis, Vytautas. "FACTORS OF THERMODYNAMICAL APPROACH TO BUILDINGS LIFE CYCLE/PASTATO GYVAVIMO CIKLO TERMODINAMINIO VERTINIMO VEIKSNIAI". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 2, n.º 7 (30 de septiembre de 1996): 75–84. http://dx.doi.org/10.3846/13921525.1996.10531660.
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The article suggests that non-industrial buildings in Lithuania consume half the final energy including appr.70% heat produced in electric power plants and boiler-houses. In order to ensure standard heating and ventilation conditions for these buildings in terms of climate parameters of a normal year it would require heat consumption of some 22 TWh. However, the energy is required not only for operation and maintenance of the building (for active microclimatic conditioning systems—AMCS), but also for setting up the building (for passive microclimatic conditioning systems—PMCS). The above input is therefore determined by technological level in the building and building materials industries. Rather exact evaluations show that in the course of several next years already, primary energy consumption used for a building maintenance shall be equal to that used while construction thereof. In terms of a building life cycle, this is a fairly short term. Therefore these buildings in terms of energetic approach make an intensive energy-consumption system. It is hereby suggested to apply an exergic analysis for a life cycle of a building under certain climatic conditions and PMCS and AMCS combinations defined by the local produce technology level. Using solely economical (both direct or derived) criteria for this intention is therefore insufficient, because the reliability of economic forecasts for longer prospect falls below any other forecasts of physical quantities. As an example for this, a globally-ecological evaluation of energetic systems based on thermodynamics is therefore presented, and is characterised by thermo-economic and exergo-economic criteria. Further, the article provides formulas and indices for thermodynamic evaluation of climatic conditions which indicate minimum requirements of exergy for operation of AMCS. Furthermore, MCS operating points and zones characteristic of different climatic regions are provided. Tasks for MCS thermodynamic analysis have been formulated to include the processes of production of building and insulation materials, and construction erection process. These should be considered the first three stages of the above task: indices of present exergic input in production of materials; forecast of potential exergic input in production of materials; thermodynamic optimisation of technological processes and equipment of building materials. It is therefore considered, that the integration of separate exergic loss components of building life cycle into a general optimisation task shall enable establishment of thermodynamically-optimum combination of exergic use in the buildings under concrete climatic conditions. This would launch, apart from economic, social and ecological aspects, an approach for handling strategic issues of construction and energetic interaction.
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Zacharias, Peter. "Perspectives of SiC Power Devices in Highly Efficient Renewable Energy Conversion Systems". Materials Science Forum 615-617 (marzo de 2009): 889–94. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.889.
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In the long run, regenerative energy sources represent the most important alternatives to fossil fuels. In general, they are characterized by decentralized logistics and supply capabilities due to ihnerent lower energetic densitiy per are, when compared with the fossil counterparts. As a result, the increased use of regenerative energy sources will require decentralized structures for energy supply, consumption optimisation and regional balancing between supply and demand. Both, the more efficient utilization of fossil energy sources and the utilization of regenerative energy sources, lead to increasingly decentralized supply structures and can be understood as being both complementary and convergent in relation to each other. Most of the converter units for utilization of decentralized energy resources (DER) use power electronics for the AC power conditioning with grid quality. The current paper shows market perspectives of DER applications and the impact of SiC on these application.
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Palka Bayard de Volo, Eleonora, Beatrice Pulvirenti, Aminhossein Jahanbin, Paolo Guidorzi y Giovanni Semprini. "Numerical Analysis on the Optimisation of Thermal Comfort Levels in an Office Located inside a Historical Building". Applied Sciences 13, n.º 5 (25 de febrero de 2023): 2954. http://dx.doi.org/10.3390/app13052954.
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The present study examines the possibility of thermal comfort optimisation inside an office room where, due to historical heritage, it is possible to modify neither the energetic characteristic of the envelope nor the position of the inlet air vents. The distribution of global and local thermal comfort indices is evaluated in both heating and cooling conditions by establishing a computational fluid dynamics (CFD) model validated against experimental data. The obtained results demonstrate a striking asymmetry of the air velocity and temperature distribution due to the low energy efficiency of the building. In heating mode, the predicted mean vote (PMV) values were improved if the discharged air from the fan coil was at its maximal velocity. However, at the same time, the vertical air temperature gradient increased by around 0.5 °C in each working station. In the cooling condition, in the absence of the solar radiation, the minimal air-flow rate satisfied the acceptable range of the draught rate (DR), whereas in the presence of a solar load, it could not meet the required cooling load in all positions, leading to higher floor temperature. The findings of this study allow for identifying and rearranging the optimal position of working stations in terms of thermal comfort.
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Fish, FE. "Influence of Hydrodynamic-Design and Propulsive Mode on Mammalian Swimming Energetics". Australian Journal of Zoology 42, n.º 1 (1994): 79. http://dx.doi.org/10.1071/zo9940079.
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Optimisation of energy by aquatic mammals requires adaptations that reduce drag, and improve thrust production and efficiency. Drag is minimised by streamlining the body and appendages. Highly derived aquatic mammals have body shapes close to the optimal hydrodynamic design for drag reduction. There is no conclusive evidence for specialised drag reduction mechanisms, although decreasing hair density is associated with reduced drag. Improvement in thrust production and efficiency is accomplished by changes in propulsive mode and appendage design. Semiaquatic mammals employ. drag-based propulsion using paddles, whereas fully aquatic mammals use lift-based propulsion with hydrofoils. Because paddling generates thrust through half the stroke cycle, propulsive efficiency is low and energetic cost is high compared with that for mammals using hydrofoils. Lift-based swimming is a rapid and high-powered propulsive mode. Oscillations of the hydrofoil generate thrust throughout the stroke cycle. For cetaceans and pinnipeds, propulsive efficiency is approximately 80%, and transport cost is below that of semiaquatic mammals. Behavioural adaptations help minimise energy expenditure by swimming mammals. Submerged swimming avoids increased drag from energy lost in formation of surface waves. Porpoising and wave riding, characteristic of dolphins, can reduce the transport costs, allowing for longer-duration swimming at high speeds.
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Duque-Prata, Amilcar, Carlos Serpa y Pedro J. S. B. Caridade. "Photochemistry of 1-Phenyl-4-Allyl-Tetrazol-5-One: A Theoretical Study Contribution towards Mechanism Elucidation". Applied Sciences 11, n.º 9 (29 de abril de 2021): 4045. http://dx.doi.org/10.3390/app11094045.
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The photodegradation mechanism of 1-phenyl-4-allyl-tetrazol-5-one has been studied using (time-dependent) density functional theory with the M06-HF, B3LYP, and PBE0 functionals and the VDZ basis set. All calculations have been carried out using the polarizable continuum model to simulate the solvent effects of methanol. The reaction pathway evolution on the triplet state has been characterised to validate a previously postulated experimental-based mechanism. The transition states and minimums have been initially located by local scanning in partial constrained optimisation, followed by a fully relaxed search procedure. The UV spectra has shown to be better described with PBE0 functional when compared with the experimental results, having the M06-HF a shift of 40 nm. From the energetic point of view, the postulated mechanism has been validated in this work showing a concerted photoextrusion of the N2 molecule. The intramolecular proton transfer occurs at a later stage of the mechanism after cyclization of the allyl group on a triplet biradical intermediate. The photoproduct observed experimentally, a pyrimidinone, has been characterised. The infrared spectroscopic reaction profile has also been proposed.
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Griffith, Matthew J., Nathan A. Cooling, Daniel C. Elkington, Michael Wasson, Xiaojing Zhou, Warwick J. Belcher y Paul C. Dastoor. "Controlling Nanostructure in Inkjet Printed Organic Transistors for Pressure Sensing Applications". Nanomaterials 11, n.º 5 (30 de abril de 2021): 1185. http://dx.doi.org/10.3390/nano11051185.
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This work reports the development of a highly sensitive pressure detector prepared by inkjet printing of electroactive organic semiconducting materials. The pressure sensing is achieved by incorporating a quantum tunnelling composite material composed of graphite nanoparticles in a rubber matrix into the multilayer nanostructure of a printed organic thin film transistor. This printed device was able to convert shock wave inputs rapidly and reproducibly into an inherently amplified electronic output signal. Variation of the organic ink material, solvents, and printing speeds were shown to modulate the multilayer nanostructure of the organic semiconducting and dielectric layers, enabling tuneable optimisation of the transistor response. The optimised printed device exhibits rapid switching from a non-conductive to a conductive state upon application of low pressures whilst operating at very low source-drain voltages (0–5 V), a feature that is often required in applications sensitive to stray electromagnetic signals but is not provided by conventional inorganic transistors and switches. The printed sensor also operates without the need for any gate voltage bias, further reducing the electronics required for operation. The printable low-voltage sensing and signalling system offers a route to simple low-cost assemblies for secure detection of stimuli in highly energetic systems including combustible or chemically sensitive materials.
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Imrie, Flora E., Marta Corno, Piero Ugliengo y Iain R. Gibson. "Computational Studies of Magnesium and Strontium Substitution in Hydroxyapatite". Key Engineering Materials 529-530 (noviembre de 2012): 123–28. http://dx.doi.org/10.4028/www.scientific.net/kem.529-530.123.
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The properties of hydroxyapatite can be improved by substitution of biologically relevant ions, such as magnesium (Mg) and strontium (Sr), into its structure. Previous work in the literature has not reached agreement as to site preferences in these substitutions, and there are suggestions that these may change with differing levels of substitution. The current work adopted a quantum mechanical approach based on density functional theory using the CRYSTAL09 code to investigate the structural changes relating to, and site preferences of, magnesium and strontium substitution (to 10 mol%) in hydroxyapatites and also to predict the corresponding vibrational spectra in the harmonic approximation. The structures underwent full geometrical optimisation within the P63 space group, indicating an energetic site preference for the Ca (2) site in the case of Mg substitution, and the Ca (1) site in the case of Sr. Shrinkage of the unit cell was observed in the case of Mg substitution, and expansion in the case of Sr substitution, in agreement with the corresponding ionic radii. Thermodynamic properties of the structures obtained from the harmonic vibrational frequency calculations confirmed that the structures were minima on the potential energy surface. Isotopic substitutions indicated that the main contribution of Sr and Mg to vibrational modes is at frequencies < 400 cm-1.
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Konieczny, Jarosław, Waldemar Rączka, Marek Sibielak y Janusz Kowal. "Energy Consumption of an Active Vehicle Suspension with an Optimal Controller in the Presence of Sinusoidal Excitations". Shock and Vibration 2020 (12 de febrero de 2020): 1–11. http://dx.doi.org/10.1155/2020/6414352.
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Control of vibration is a significant problem in the design and construction of vehicle suspensions. The usage of controlled suspensions is important due to ride comfort, driving safety, and vehicle road holding. The control law for such systems is usually determined as a solution of an optimisation problem with a quality indicator. The effectiveness of vibration reduction is possible to be improved in the entire useful frequency range of a system operation, but usually increasing external energy consumption is observed. An additional problem in the case of vehicle suspensions includes the necessity for increased vibration reduction at selected frequencies. This is related to the natural frequencies of the driver’s internal organs or to other reasons. The goal of this work is to find a compromise between efficiency of the suspension in terms of the aforementioned indicators and energy consumption in the presence of sinusoidal excitations. This paper presents a synthesis of a weighted multitone optimal controller (WMOC) for an active vibration reduction system. Energy limitation is taken into account by selection coefficients of the weighting matrix associated with the control signal vector. The control signal in this case is determined on the basis of the parameter estimation of the sinusoidal disturbances vector (PESDV). The vibration transmissibility function and the energetic indicators for the active suspension were determined while taking note of nonlinearities occurring in the actual vehicle. The analysis of energy indicators is presented, depending on the level of vibration reduction efficiency. The results were compared with referencing to LQR control strategy.
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Yezeguelian, Axel y Askin T. Isikveren. "Methods to improve UAV performance using hybrid-electric architectures". Aircraft Engineering and Aerospace Technology 92, n.º 5 (16 de abril de 2020): 685–700. http://dx.doi.org/10.1108/aeat-11-2019-0227.
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Purpose When comparing and contrasting different types of fixed-wing military aircraft on the basis of an energetic efficiency figure-of-merit, unmanned aerial vehicles (UAVs) dedicated to tactical medium-altitude long-endurance (MALE) operations appear to have significant potential when hybrid-electric propulsion and power systems (HEPPS) are implemented. Beginning with a baseline Eulair drone, this paper aims to examine the feasibility of retro-fitting with an Autarkic-Parallel-HEPPS architecture to enhance performance of the original single diesel engine. Design/methodology/approach In view of the low gravimetric specific energy performance attributes of batteries in the foreseeable future, the best approach was found to be one in which the Parallel-HEPPS architecture has the thermal engine augmented by an organic rankine cycle (ORC). For this study, with the outer mould lines fixed, the goal was to increase endurance without increasing the Eulair drone maximum take-off weight beyond an upper limit of +10%. The intent was to also retain take-off distance and climb performance or, where possible, improve upon these aspects. Therefore, as the focus of the work was on power scheduling, two primary control variables were identified as degree-of-hybridisation for useful power and cut-off altitude during the en route climb phase. Quasi-static methods were used for technical sub-space modelling, and these modules were linked into a constrained optimisation algorithm. Findings Results showed that an Autarkic-Parallel-HEPPS architecture comprising an ORC thermal energy recovery apparatus and high-end year-2020 battery, the endurance of the considered aircraft could be increased by 11%, i.e. a total of around 28 h, including de-icing system, in-flight recharge and emergency aircraft recovery capabilities. The same aircraft with the de-icing functionality removed resulted in a 20% increase in maximum endurance to 30 h. Practical implications Although the adoption of Series/Parallel-HEPPS only solutions do tend to generate questionable improvements in UAV operational performance, combinations of HEPPS with energy recovery machines that use, for example, an ORC, were found to have merit. Furthermore, such architectural solutions could also offer opportunity to facilitate additional functions like de-icing and emergency aircraft recovery during engine failure, which is either not available for UAVs today or prove to be prohibitive in terms of operational performance attributes when implemented using a conventional PPS approach. Originality/value This technical paper highlights a new degree of freedom in terms of power scheduling during climbing transversal flight operations. A control parameter of cut-off altitude for all types of HEPPS-based aircraft should be introduced into the technical decision-making/optimisation/analysis scheme and is seen to be a fundamental aspect when conducting trade-studies with respect to degree-of-hybridisation for useful power.
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Abiona, Olaitan, David Wyatt, Jasdip Koner y Afzal Mohammed. "The Optimisation of Carrier Selection in Dry Powder Inhaler Formulation and the Role of Surface Energetics". Biomedicines 10, n.º 11 (26 de octubre de 2022): 2707. http://dx.doi.org/10.3390/biomedicines10112707.
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This review examines the effects of particle properties on drug–carrier interactions in the preparation of a dry powder inhaler (DPI) formulation, including appropriate mixing technology. The interactive effects of carrier properties on DPI formulation performance make it difficult to establish a direct cause-and-effect relationship between any one carrier property and its effect on the performance of a DPI formulation. Alpha lactose monohydrate remains the most widely used carrier for DPI formulations. The physicochemical properties of α-lactose monohydrate particles, such as particle size, shape and solid form, are profoundly influenced by the method of production. Therefore, wide variations in these properties are inevitable. In this review, the role of surface energetics in the optimisation of dry powder inhaler formulations is considered in lactose carrier selection. Several useful lactose particle modification methods are discussed as well as the use of fine lactose and force control agents in formulation development. It is concluded that where these have been investigated, the empirical nature of the studies does not permit early formulation prediction of product performance, rather they only allow the evaluation of final formulation quality. The potential to leverage particle interaction dynamics through the use of an experimental design utilising quantifiable lactose particle properties and critical quality attributes, e.g., surface energetics, is explored, particularly with respect to when a Quality-by-Design approach has been used in optimisation.
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Gobrecht, David, John M. C. Plane, Stefan T. Bromley, Leen Decin, Sergio Cristallo y Sanjay Sekaran. "Bottom-up dust nucleation theory in oxygen-rich evolved stars". Astronomy & Astrophysics 658 (febrero de 2022): A167. http://dx.doi.org/10.1051/0004-6361/202141976.
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Context. Aluminium oxide (alumina; Al2O3) is a promising candidate as a primary dust condensate in the atmospheres of oxygen-rich evolved stars. Therefore, alumina ‘seed’ particles might trigger the onset of stellar dust formation and of stellar mass loss in the wind. However, the formation of alumina dust grains is not well understood. Aims. We aim to shed light on the initial steps of cosmic dust formation (i.e. nucleation) in oxygen-rich environments via a quantum-chemical bottom-up approach. Methods. Starting with an elemental gas-phase composition, we construct a detailed chemical-kinetic network that describes the formation and destruction of aluminium-bearing molecules and dust-forming (Al2O3)n clusters up to the size of dimers (n = 2) coagulating to tetramers (n = 4). Intermediary species include the prevalent gas-phase molecules AlO and AlOH as well as AlxOy clusters with x = 1–5, y = 1–6. The resulting extensive network is applied to two model stars, which represent a semi-regular variable and a Mira type, and to different circumstellar gas trajectories, including a non-pulsating outflow and a pulsating model. The growth of larger-sized (Al2O3)n clusters with n = 4–10 is described by the temperature-dependent Gibbs free energies of the most favourable structures (i.e. the global minima clusters) as derived from global optimisation techniques and calculated via density functional theory. We provide energies, bond characteristics, electrostatic properties, and vibrational spectra of the clusters as a function of size, n, and compare these to corundum, which corresponds to the crystalline bulk limit (n →∞). Results. The circumstellar aluminium gas-phase chemistry in oxygen-rich giants is primarily controlled by AlOH and AlO, which are tightly coupled by the reactions AlO+H2, AlO+H2O, and their reverse. Models of semi-regular variables show comparatively higher AlO abundances, as well as a later onset and a lower efficiency of alumina cluster formation when compared to Mira-like models. The Mira-like models exhibit an efficient cluster production that accounts for more than 90% of the available aluminium content, which is in agreement with the most recent ALMA observations. Chemical equilibrium calculations fail to predict both the alumina cluster formation and the abundance trends of AlO and AlOH in the asymptotic giant branch dust formation zone. Furthermore, we report the discovery of hitherto unreported global minimum candidates and low-energy isomers for cluster sizes n = 7, 9, and 10. A homogeneous nucleation scenario, where Al2O3 monomers are successively added, is energetically viable. However, the formation of the Al2O3 monomer itself represents an energetic bottleneck. Therefore, we provide a bottom-up interpolation of the cluster characteristics towards the bulk limit by excluding the monomer, approximately following an n−1∕3 dependence.
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Thenius, Ronald, Thomas Schmickl y Karl Crailsheim. "Optimisation of a honeybee-colony's energetics via social learning based on queuing delays". Connection Science 20, n.º 2-3 (septiembre de 2008): 193–210. http://dx.doi.org/10.1080/09540090802091982.
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De Jong, Maarten, Rangan K. Dutta, Marcel H. F. Sluiter, Alexis G. Miroux, Sybrand van der Zwaag, Jilt Sietsma y Pedro E. J. Rivera-Díaz-del-Castillo. "First-Principles and Genetic Modelling of Precipitation Sequences in Aluminium Alloys". Solid State Phenomena 172-174 (junio de 2011): 285–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.172-174.285.
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Aluminium alloys display complex phase transitions to achieve their desired properties.Many of these involve elaborated precipitation sequences where the main role is not played by ther-modynamically stable species, but by metastable precipitates instead. An interplay between phasestability, crystal symmetry, diffusion, volume and particle/matrix interfaces sets the pace for the ki-netics. Thermodynamic modelling, which focuses on stable precipitates, is not an aid in describingsuch processes, as it is usually transitional phases that achieve the desired properties. The model pre-sented here combines first--principles to obtain the transition precipitate energetics (both at the bulkand at the interface with the matrix) with thermochemical databases to describe the overall kineticsof stable precipitates. Precipitate size and number density are captured via the Kampmann--Wagnernumerical approach, which is embedded in a genetic algorithm to obtain optimal compositional andheat treatment scenarios for the optimisation of the mechanical properties in aluminium alloys of the 7000 series.
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Flikkema, Edwin, Kim E. Jelfs y Stefan T. Bromley. "Structure and energetics of hydroxylated silica clusters, (SiO2)M(H2O)N, M=8, 16 and N=1−4: A global optimisation study". Chemical Physics Letters 554 (diciembre de 2012): 117–22. http://dx.doi.org/10.1016/j.cplett.2012.10.016.
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Rotilio, Marianna. "Product innovation between circular economy and Industry 4.0". TECHNE - Journal of Technology for Architecture and Environment, 29 de julio de 2021, 192–200. http://dx.doi.org/10.36253/techne-10598.
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In the construction sector, the new Industry 4.0 and circular economy paradigms are currently playing an increasingly important role in order to respond to demands for energetic efficiency, optimisation of resource usage, automation and production activities monitoring. Therefore, this article aims to at illustrate industrial research and an experimental development activity that led to the creation of an innovative product named MULTIFId. It consists of an intelligent, economical and low-emission panel, made with waste from the paper and cardboard industrial manufacturing process which intends to contribute to the development of the fundamental enabling technology of “Advanced Materials” for Intelligent Factories.
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Dolier, Ewan, Martin King, Robbie Wilson, Ross Gray y Paul McKenna. "Multi-parameter Bayesian optimisation of laser-driven ion acceleration in particle-in-cell simulations". New Journal of Physics, 1 de julio de 2022. http://dx.doi.org/10.1088/1367-2630/ac7db4.
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Abstract High power laser-driven ion acceleration produces bright beams of energetic ions that have the potential to be applied in a wide range of sectors. The routine generation of optimised and stable ion beam properties is a key challenge for the exploitation of these novel sources. We demonstrate the optimisation of laser-driven proton acceleration in particle-in-cell simulations controlled by a Bayesian algorithm. Optimal laser and plasma conditions are identified four times faster for two input parameters, and approximately one thousand times faster for four input parameters, when compared to systematic and linear parametric variation. In addition, a non-trivial optimal condition for the front surface density scale length is discovered, which would have been difficult to identify by single variable scans. This approach enables rapid identification of optimal laser and target parameters in simulations, for use in guiding experiments, which has the potential to significantly accelerate the development and application of laser-plasma-based ion sources.
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Prikupets, Leonid B., George V. George V. Boos, Vladislav G. Terekhov y Ivan G. Tarakanov. "Optimisation of Lighting Parameters of Irradiation in Light Culture of Lettuce Plants Using LED Emitters". Light & Engineering, octubre de 2019, 43–54. http://dx.doi.org/10.33383/2019-063.
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The results of the ending phase of photo biological studies of capacity of lettuce and basil grown in conditions of a phytotron with irradiation by radiation of different ratio of fractions in the red-blue and blue-green-red regions of photosynthetic active radiation (PAR) are presented. The spectral variants of PAR providing the maximum or near to maximum capacity of the specified cultures are found. The complex and multiple-valued nature of effect of main PAR spectral regions on photo energetic and photo regulatory processes in plants providing their capacity is highlighted, which makes it impossible to determine common unified requirements to optimal parameters of artificial irradiation for growing of plants. These requirements shall be defined on the basis of direct photo biological experiments with main species of agricultural plants and be the most important element of the general photo culture macro technology. The general principles of fulfilment of the specified requirements to PAR spectra of phytoemitters are reviewed, including with consideration of setting of normal vision conditions for personnel of greenhouses and other protected ground structures.
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Vela-Martín, Alberto. "Subgrid-scale models of isotropic turbulence need not produce energy backscatter". Journal of Fluid Mechanics 937 (22 de febrero de 2022). http://dx.doi.org/10.1017/jfm.2022.123.
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This investigation questions the importance of inverse interscale energy fluxes, the so-called energy backscatter, for the modelling of the energy cascade in large-eddy simulations (LES) of turbulent flows. The invariance of the filtered Navier–Stokes equations to divergence-preserving transformations of the subgrid-scale (SGS) stress tensor is exploited here to explore alternative representations of the local SGS energy fluxes. Numerical optimisation procedures are applied to the SGS stress tensor – obtained by filtering isotropic turbulence flow fields – to find alternative stresses that satisfy the filtered Navier–Stokes equations, but that produce negligible backscatter. These alternative SGS stresses show that backscatter represents not a flux of energy from the subgrid to the resolved scales, but conservative spatial fluxes, and that it need not be modelled to reproduce the local energetic exchange between the resolved and the subgrid scales in LES. From the perspective of statistical mechanics, it is argued that this is a consequence of the strong statistical irreversibility of inertial-range dynamics, which precludes inverse energy cascades even in a local sense. These findings show that the energy cascade is strongly unidirectional locally, and that it can be modelled as an irreversible sink of energy, justifying the extended use of purely dissipative SGS models in LES.
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Hubacek, J., P. Suchanek y V. Lanska. "Short-term trajectories of exercise-induced plasma lipid changes in overweight females, with a focus on HDL cholesterol". European Journal of Preventive Cardiology 29, Supplement_1 (1 de mayo de 2022). http://dx.doi.org/10.1093/eurjpc/zwac056.183.
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Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health, Czech Republic Background Increased levels of plasma lipoproteins are among the modifiable risk factors of cardiovascular disease. Dietary changes and increased physical activity are the most powerful non-pharmacological interventions for the optimisation of plasma lipid levels. Objectives The aim of our study was to investigate the effect of an intensive short-term lifestyle intervention on plasma lipid trajectories in overweight non-diabetic females. Materials and Methods Two hundred and two healthy overweight (BMI > 27.5 kg/m2) females underwent an intensive short-term (10-week) intervention (at least four units of 1-hour exercise activity weekly at optimal energetic intake) aimed at lowering body weight. Plasma lipid (TC, LDL-C, HDL-C, TG) levels were examined at baseline and every two weeks over the course of the 10-week intervention. Results There was a significant decrease in BMI (Δ -4.7%, P<0.001) and body weight (Δ -4.9%, P<0.001) after the intervention. Positive changes (decreases) in TC (Δ -8%, P<0.001), TG (Δ -9%, P<0.001) and LDL-C (Δ -11%, P<0.001) were observed immediately after two weeks, but levels did not decrease further. In contrast, HDL-C did not increase as expected: after two weeks of intervention, we observed a significant decrease of about 6% (P<0.001) followed by a slow return to baseline values. But even after ten weeks of intervention, HDL-C values had not reached the values detected at baseline. Conclusion In overweight females, HDL-C decreased after short-term intensive lifestyle intervention. To confirm the protective effect of increased physical activity, plasma lipids need to be examined over a longer time period.
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Thirunavukarasu, S., N. Jex, A. Chowdhary, I. Hassan, S. Straw, D. Broadbent, P. Swoboda et al. "Mechanistic insights from a multiparametric magnetic resonance imaging study regarding the role of sodium glucose co-transporter 2 inhibitors". European Heart Journal 42, Supplement_1 (1 de octubre de 2021). http://dx.doi.org/10.1093/eurheartj/ehab724.0263.
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Abstract Background Type 2 diabetes (T2D) is associated with an increased risk of heart failure (HF) and cardiovascular (CV) mortality. Sodium–glucose-co transporter-2 (SGLT2) inhibitors reduce the risk of major adverse CV events and hospitalisation for HF in T2D patients with high cardiovascular risk, despite only a modest improvement in glycemic control. Restoring cellular energy homeostasis and reversing adverse cardiac remodelling in diabetes have been speculated as a potential metabolic modulatory effect of SGLT2 inhibitors leading to their beneficial CV outcomes. Myocardial energy deficient states can be detected non-invasively by 31-phosphorus magnetic resonance spectroscopy (31P-MRS). Objectives Utilising cardiovascular magnetic resonance imaging (CMR) and 31P-MRS in a single centre longitudinal cohort study, we aimed to investigate the effects of the selective SGLT2 inhibitor empagliflozin on myocardial energetics, function, perfusion, and myocardial cellular volume in patients with T2D. Methods Eighteen consecutive T2D patients who were commenced on empagliflozin in cardiometabolic optimisation clinics underwent CMR and 31P-MRS scans before and after twelve-week empagliflozin treatment, and plasma N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) levels were measured. Ten controls with no diabetes underwent an identical 31P-MRS and CMR protocol on a single visit. Results When compared to controls, patients with T2D showed: lower myocardial energetics (1.52±0.40 vs 2.20±0.5, p=0.0005), lower stress myocardial blood flow (1.60±0.50 vs 2.10±0.50, p=0.02) and lower left ventricular ejection fraction (52±13% vs 63±4%, p=0.01). Treatment with empagliflozin led to significant improvements in myocardial energetics (PCr/ATP: 1.52 to 1.76, p=0.009). This was accompanied by a relative 13% improvement in left ventricular ejection fraction (p=0.001), 3% improvement in global longitudinal strain (p=0.01), 61% reduction in NTproBNP (p=0.05), and 9% reduction in myocardial cell volume (p=0.04). No significant change in myocardial blood flow or diastolic strain was detected. Conclusions For the first time, we demonstrate that empagliflizon improves myocardial energetics and function, reduces myocardial cellular volume, and reduces NT-proBNP levels in patients with T2D. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): British Heart Foundation PCr/ATPLVEF
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Leboucher, Heloïse, Aude Simon y Mathias Rapacioli. "Structures and stabilities of PAH clusters solvated by water aggregates: the case of the pyrene dimer". Journal of Chemical Physics, 27 de febrero de 2023. http://dx.doi.org/10.1063/5.0139482.
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Whereas clusters made of polycyclic aromatic hydrocarbon and water monomers are relevant objects in both atmospheric and astrophysical science, little is known about their energetic and structural properties. In this work, we perform global explorations of the potential energy landscapes of neutral clusters made of two pyrene units and one to ten water molecules using a Density-Functional based Tight-Binding (DFTB) potential followed by local optimisations at the Density-Functional Theory level. We discuss the binding energies with respect to various dissociation channels. It shows that cohesion energies of the water clusters interacting with a pyrene dimer is larger than that of the pure water clusters, reaching for the largest clusters an asymptotic limit similar to that of pure water clusters and that, while the hexamer and octamer can be considered as magic numbers for isolated water clusters, it is not the case anymore when they are interacting with a pyrene dimer. Ionisation potentials are also computed making use of the Configuration Interaction extension of DFTB and we show that in cations the charge is mostly carried by the pyrene molecules.