4,777 research outputs found
Power Smoothing Control in a Grid-Connected Marine Current Turbine System for Compensating Swell Effect
No full textVariations of marine current speed may lead to strong fluctuations in the power extracted by a marine current turbine (MCT). During short-time period, swell effect is the main cause for the current speed variations. Conventional tip speed ratio Maximum Power Point Tracking (MPPT) algorithm will require the MCT to accelerate or to decelerate frequently under swell effect, which can cause severe fluctuations in the generator power. This paper focuses on power smoothing control of grid-connected MCT system. In the first step, a modified MPPT algorithm with filter strategy is proposed in generator-side control to mitigate the fluctuation of generator power. In the second step, Super-capacitor (SC) Energy Storage System (ESS) is added to compensate the residual power fluctuations. Simulations of a 1.5 MW direct-driven grid-connected MCT system are carried out. The swell effect is calculated based on typical system location and sea state. Detailed control strategies and SC sizing are described. The results demonstrate that the association of the generator-side filter strategy with the SC ESS system achieves a smoothed power injected to the grid in case of swell disturbancesThis work is supported by Brest Métropole Océane (BMO)
Yeast metabolism in fresh and frozen dough : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand
No full textAuthor also known as SM LovedayFresh bakery products have a very short shelf life, which limits the extent to which manufacturing can be centralised. Frozen doughs are relatively stable and can be manufactured in large volumes, distributed and baked on-demand at the point of sale or consumption. With appropriate formulation and processing a shelf life of several months can be achieved.Shelf life is limited by a decline in proofing rate after thawing, which is attributed to a) the dough losing its ability to retain gas and b) insufficient gas production, i.e. yeast activity. The loss of shelf life is accelerated by delays between mixing and freezing, which allow yeast cells the chance to ferment carbohydrates.This work examined the reasons for insufficient gas production after thawing frozen dough and the effect of pre-freezing fermentation on shelf life. Literature data on yeast metabolite dynamics in fermenting dough were incomplete. In particular there were few data on the accumulation of ethanol, a major fermentation end product which can be injurious to yeast.Doughs were prepared in a domestic breadmaker using compressed yeast from a local manufacturer and analysed for glucose, fructose, sucrose, maltose and ethanol. Gas production after thawing declined within 48 hours of frozen storage. This was accelerated by 30 or 90 minutes of fermentation at 30;C prior to freezing.Sucrose was rapidly hydrolysed and yeast consumed glucose in preference to fructose. Maltose was not consumed while other sugars remained. Ethanol, accumulated from consumption of glucose and fructose, was produced in approximately equal amounts to CO2, indicating that yeast cells metabolised reductively.Glucose uptake in fermenting dough followed simple hyperbolic kinetics and fructose uptake was competitively inhibited by glucose. Mathematical modelling indicated that diffusion of sugars and ethanol in dough occurred quickly enough to eliminate solute gradients brought about by yeast metabolism
Probing conventional and new physics at the ESS with coherent elastic neutrino-nucleus scattering
No full textAbstract We explore the potential of the European Spallation Source (ESS) in probing physics within and beyond the Standard Model (SM), based on future measurements of coherent elastic neutrino-nucleus scattering (CEνNS). We consider two SM physics cases, namely the weak mixing angle and the nuclear radius. Regarding physics beyond the SM, we focus on neutrino generalized interactions (NGIs) and on various aspects of sterile neutrino and sterile neutral lepton phenomenology. For this, we explore the violation of lepton unitarity, active-sterile oscillations as well as interesting upscattering channels such as the sterile dipole portal and the production of sterile neutral leptons via NGIs. The projected ESS sensitivities are estimated by performing a statistical analysis considering the various CEνNS detectors and expected backgrounds. We find that the enhanced statistics achievable in view of the highly intense ESS neutrino beam, will offer a drastic improvement in the current constraints obtained from existing CEνNS measurements. Finally, we discuss how the ESS has the potential to provide the leading CEνNS-based constraints, complementing also further experimental probes and astrophysical observations
Converting SrI <sub>2</sub> :Eu <sup>2+</sup> into a near infrared scintillator by Sm <sup>2+</sup> co-doping
No full text The luminescence and scintillation properties of SrI 2 single crystals doped with 5% Eu 2+ and 0.05%, 0.2% and 0.5% Sm 2+ are evaluated. X-ray excited and photoluminescence measurements show energy transfer from excited Eu 2+ ions to Sm 2+ ions. At a concentration of 0.5% Sm 2+ , the luminescence consists almost entirely of 740 nm emission from Sm 2+ 5d-4f transitions. Co-doping SrI 2 :5% Eu 2+ with Sm 2+ provides a novel method to bypass the self-absorption problem encountered in large SrI 2 :Eu 2+ crystals and, at the same time, provides a unique near-infrared emitting scintillator with a light yield of approximately 40,000 photons/MeV. Accepted Author ManuscriptRST/Fundamental Aspects of Materials and EnergyRST/Luminescence Material
'Laws 'Needefull in Later to be Abrogated': Intersex and the Sources of Christian Theology
No full textThis is the author accepted manuscript. The final version is available from Palgrave Macmillan via the DOI in this record
Introduction: Troubling Bodies?
No full textThis is the author accepted manuscript. The final version is available from Palgrave Macmillan via the DOI in this record
Hunting the elusive X17 in CEνNS at the ESS
No full textThe so-called X17 particle has been proposed in order to explain a very significant resonant behaviour (in both the angular separation and invariant mass)of e+e− pairs produced during a nuclear transition of excited 8Be, 4He and 12Cnuclei. Fits to the corresponding data point, as most probable explanation, to aspin-1 object, which is protophobic and has a mass of approximately 16.7 MeV, which then makes the X17 potentially observable in Coherent Elastic neutrino (ν)Nucleus Scattering (CEνNS) at the European Spallation Source (ESS). By adopting as theoretical framework a minimal extension of the Standard Model (SM) with a generic U(1)′ gauge group mixing with the hypercharge one of the latter, which can naturally accommodate the X17 state compliant with all available measurements from a variety of experiments, we predict that CEνNS at the ESS will constitute an effective means to probe this hypothesis, even after allowing for the inevitable systematics associated to the performance of the planned detectors therein
Phonon-assisted energy transfer in Er-exchanged LiNbO3
No full textRaman microprobe spectroscopy measurements show, that in contrast to Er-idiffusion, Er-exchange proc- ess leads to significant change of the lattice vibration spectrum of LiNbO3. Therefore, our data allow to assume that the drastic suppression of parasitic upconversion in the Er-exchanged LiNbO3 are caused by multiphonon nonradiative decay of the 2(4F9/2) state, providing fast nonradiative energy transfer to the 4G11/2 and (4F7/2+4I13/2) states
Intrafullerene electron transfers in Sm-containing metallofullerenes: Sm@C-2n (74 <= 2n <= 84)
No full textThe electronic properties of Sm-containing metallofullerenes, Sm@C-74, Sm@C-76 (I, II), Sm@C-78, Sm@C-80, Sm@C-82 (I, II, III) and Sm@C-84 (I, II, III), are characterized by UV-Vis-NIR absorption spectroscopy and electron energy-loss spectroscopy (EELS). the UV-Vis-NIR absorption spectra of Sm@C-74, Sm@C-80, Sm@C-82 (I, II, III) and Sm@C-84 (I, II) are quite similar to those of the corresponding Ca, Sr, Ba, Eu, Tm, Yb-based metallofullerenes. In contrast, the absorption spectra of Sm@C-76 (I, II), Sm@C-78 and Sm@C-84(III) show a novel feature: the onset for Sm@C-78 is observed similar to 2600 nm, which corresponds to a small band gap (similar to0.5 eV). Furthermore, the oxidation states of Sm atom in the various fullerene cages are investigated by EELS, which reveals that the Sm atom takes +2 oxidation state in the fullerene cages. A probable rationale for the tendency to have the Sm2+ state is presented based on a simple thermochemical cycle model. (C) 2001 by Elsevier Science Inc.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000168906500014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Biochemical Research MethodsBiochemistry & Molecular BiologyComputer Science, Interdisciplinary ApplicationsCrystallographyMathematical & Computational BiologySCI(E)EI30ARTICLE2244-2511
beta-decay spectroscopy of neutron-rich Sm-160,Sm-161,Sm-162 isotopes
No full textNeutron-rich Sm-160,Sm-161,Sm-162 isotopes have been populated at the RIBF, RIKEN via beta decay for the first time. beta-coincident gamma rays were observed in all three isotopes including gamma rays from the isomeric decay of Sm-160 and Sm-162. The isomers in Sm-160 and Sm-162 have previously been observed but have been populated via beta decay for the first time. The isomeric state in Sm-162 is assigned a 4(-) nu 7/2(+)[633]circle times nu 1/2(-)[521] configuration based on the decay pattern. The level schemes of Sm-160 and Sm-162 are presented. The ground states in the parent nuclei Pm-160 and Pm-162 are both assigned a 6(-) nu 7/2(+)[633]circle times pi 5/2(-)[532] configuration based on the population of states in the daughter nuclei. Blocked BCS calculations were performed to further investigate the spin-parities of the ground states in Pm-160, Pm-161, and Pm-162, and the isomeric state in Sm-162.CPCI-S(ISTP)[email protected]
- …
