1,983 research outputs found
renewable sources integration through the optimization of the load for residential applications
Abstract This work presents the implementation of two different control strategies for the control of Microgrids a Model Predictive Control (MPC) technique coupled with a Mixed-Integer Linear Program (MILP) structure and a Rule Based Control (RBC) strategy both applied to a residential MicroGrid. The validation of the models has been performed with an experimental setup laid out in the laboratory of University of Rome - Tor Vergata. Results obtained show that MicroGrids connected to the main network have enough potential to support grid balancing actions, thus allowing for a greater penetration of renewable sources into the mix, and giving economic benefits for both end users and providers. In particular, using a MPC strategy major benefits can be obtained in terms of reduction of the unbalanced energy exchange with the main grid and a more efficient use of the micro-grid components
Grid-connected Microgrids to Support Renewable Energy Sources Penetration
Abstract Distributed generation systems and microgrids are instrumental for a greater penetration of renewables to achieve a substantial reduction on carbon emissions. However, microgrids performances and reliability strongly depend on the continuous interaction between power generation, storage and load requirements, highlighting the importance in developing a proper energy management strategy and the relative control system. In this work a Model predictive Control (MPC) strategy, based on a Mixed Linear Integer Programming framework, has been applied to a residential microgrid case. Theoretical results obtained confirm that grid connected microgrids have potential capabilities in grid balancing allowing for a larger penetration of fluctuating renewable energy sources and thus producing economic benefits for both end-user and grid operators. A microgrid test bench to reproduce previous microgrid model is also presented in the paper. The experimental setup has been used to validate results obtained from simulation. Results obtained confirm the potential of this solution and its real applicability
Complete genome sequence of the hippuricase-positive Campylobacter avium Type 5 LMG 24591
cited By 0Campylobacter avium is a thermotolerant Campylobacter species that has been isolated from poultry. C. avium was also the second hippuricase-positive species to be identified within Campylobacter. Here, we present the genome sequence of the C. avium type strain LMG 24591 (= CCUG 56292T), isolated in 2006 from a broiler chicken in Italy. © 2017 Miller et al.Peer reviewe
Kinetics of the thermal degradation of Erica arborea by DSC: Hybrid kinetic method
The scope of this work was the determination of kinetic parameters of the
thermal oxidative degradation of a Mediterranean scrub using a hybrid method
developed at the laboratory. DSC and TGA were used in this study under air
sweeping to record oxidative reactions. Two dominating and overlapped
exothermic peaks were recorded in DSC and individualized using an experimental
and numerical separation. This first stage allowed obtaining the enthalpy
variation of each exothermic phenomenon. In a second time, a model free method
was applied on each isolated curve to determine the apparent activation
energies. A reactional kinetic scheme was proposed for the global exotherm
composed of two independent and consecutive reactions. In fine mean values of
enthalpy variation and apparent activation energy previously determined were
injected in a model fitting method to obtain the reaction order and the
preexponential factor of each oxidative reaction. We plan to use these data in
a sub-model to be integrated in a wildland fire spread model
MONENSINA E URÉIA DE LIBERAÇÃO LENTA NO DESEMPENHO DE BOVINOS CONFINADOS
O objetivo do presente experimento foi determinar os efeitos do ionóforo monensina
(Rumensin ), uma fonte de uréia de liberação lenta (Anipro ) e sua associação em bovinos
confinados. Foram utilizados 92 bovinos bloqueados por raça e peso e distribuídos aleatoriamente em
quatro grupos: grupo controle (n=23); grupo Rumensin (n=25); grupo Anipro (n=23); e o grupo da
associação de ambos (n=22). Os animais receberam dietas totais misturadas a base de silagem de
milho, milho moído e caroço de algodão, contendo níveis iguais de energia (70% NDT) e proteína
bruta (12%). Os dois grupos que receberam Anipro apresentaram ingestão alimentar
significativamente menor do que os grupos controle e Rumensin , o que levou a ganho médio diário,
peso final e peso de carcaça significativamente menores, porém sem efeito sobre conversão
alimentar ou rendimento de carcaça. Não se observou qualquer efeito de Rumensin , possivelmente
devido ao baixo nível de proteína bruta da dieta, ou também ao baixo nível de proteína verdadeira da
dieta. Também não houve efeito significativo da interação entre os dois componentes.
Monensin and slow-release urea on the performance of feedlot steers
Abstract
The objective of the present experiment was to determine the effects of the ionophore
monensin (Rumensin ), a slow-release source of urea (Anipro ) and their association on feedlot
cattle. A total of 92 steers were blocked by breed and weight and were randomly assigned to four
groups: Control group (n=23); Rumensin group (n=25); Anipro group (n=23); and the association
group (n=22). They received total mixed rations based on corn silage, ground corn and cottonseed,
with equal levels of energy (70% TDN) and crude protein (12%). Both groups receiving Anipro
showed a significantly lower feed intake, which led to significantly lower average daily gain, slaughter
and carcass weight, with no effect on feed conversion and carcass yield. No effect of Rumensin was
seen, possibly due to the low crude protein level of the diets, as well as the low level of true protein.
There was also no significant effect on the interaction of the two components
Gauge equivalence in QCD: the Weyl and Coulomb gauges
The Weyl-gauge ( QCD Hamiltonian is unitarily transformed to a
representation in which it is expressed entirely in terms of gauge-invariant
quark and gluon fields. In a subspace of gauge-invariant states we have
constructed that implement the non-Abelian Gauss's law, this unitarily
transformed Weyl-gauge Hamiltonian can be further transformed and, under
appropriate circumstances, can be identified with the QCD Hamiltonian in the
Coulomb gauge. We demonstrate an isomorphism that materially facilitates the
application of this Hamiltonian to a variety of physical processes, including
the evaluation of -matrix elements. This isomorphism relates the
gauge-invariant representation of the Hamiltonian and the required set of
gauge-invariant states to a Hamiltonian of the same functional form but
dependent on ordinary unconstrained Weyl-gauge fields operating within a space
of ``standard'' perturbative states. The fact that the gauge-invariant
chromoelectric field is not hermitian has important implications for the
functional form of the Hamiltonian finally obtained. When this nonhermiticity
is taken into account, the ``extra'' vertices in Christ and Lee's Coulomb-gauge
Hamiltonian are natural outgrowths of the formalism. When this nonhermiticity
is neglected, the Hamiltonian used in the earlier work of Gribov and others
results.Comment: 25 page
Obtention of Hard Coating Using Electrochemical Process in Aluminum-Silicon Alloys for Automotive Vehicles
Automotive industry is searching for new ways to improve vehicles’ energy efficiency through mass reduction, using aluminum alloys. This change requires a surface protection to extend the life cycle of the components and aluminum anodization is the most used solution. This research is focused on the intake and exhaust ducts’ surfaces of aluminum internal combustion engines cylinder head, which are subject to chemical agents and temperature variation. To extend the working life of this component it is necessary to obtain a covering protective layer. The process targeted the anodization of an internal surface of a much larger part of a cast aluminum-silicon alloy cylinder head. The anodization was obtained using a H2SO4 solution (184 g.L-1) and a DC voltage starting at 20 V. The Al2O3 layer obtained, inside the cylinder head´s ducts, has an average thickness of 120 µm in accordance with the proposal of providing a suitable surface protection
Thermal performance of a solar hybrid dryer for Conilon coffee (Coffea canephora)
The study was aimed at design and development of an energy efficient hybrid solar
dryer suitable for drying of organic Conilon coffee placed in the town of Seropédica, Rio de
Janeiro, Brazil. The energy efficiency and the drying efficiency were the evaluation criteria for
thermal performance of the hybrid solar dryer during the coffee drying. Temperature and relative
humidity (RH) of the drying and ambient air, solar radiation intensity and coffee weight loss were
monitored during the drying process. The process occurred over six consecutive days; the drying
time was from 07:00 to 17:00 h, totalling 120 h of operation with an intermittent period (at night)
of 14 h. During intermittence, the exhaust system kept off and solar collector and drying chamber
sealed. The effective drying period took 60 h, with temperature and RH, respectively, of 38.3 °C
and 60.6% outlet of the solar collector, 32.7 °C and 72.2% outlet drying chamber and 27.8 °C
and 74.5% ambient air. The maximum temperature in the solar collector and drying chamber
reached 54 and 47.7 °C, respectively, with an ambient air temperature of 32 °C at 12:00 h. These
values showing temperature increase 22.2 °C in solar collector and 10 ºC drying chamber. The
mean variation for the reduction in RH between the drying air inside the solar collector and the
ambient air was 28%, while in the chamber obtained in a range of 10.5% at 13:00 h. The solar
collector and dryer chamber efficiency were 29.1 and 40.8%, respectively, while the overall dryer
efficiency 39.7%
Observable gravitational waves from tidal disruption events and their electromagnetic counterpart
Large scale structure and cosmolog
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