1,122 research outputs found
Cyber Physical Energy Systems Modules for Power Sharing Controllers in Inverter Based Microgrids
The Microgrids (MGs) are an effective way to deal with the smart grid challenges, including service continuity in the event of a grid interruption, and renewable energy integration. The MGs are compounded by multiple distributed generators (DGs), and the main control goals are load demand sharing and voltage and frequency stability. Important research has been reported to cope with the implementation challenges of the MGs including the power sharing control problem, where the use of cybernetic components such as virtual components, and communication systems is a common characteristic. The use of these cybernetic components to control complex physical systems generates new modeling challenges in order to achieve an adequate balance between complexity and accuracy in the MG model. The standardization problem of the cyber-physical MG models is addressed in this work, using a cyber-physical energy systems (CPES) modeling methodology to build integrated modules, and define the communication architectures that each power sharing control strategy requires in an AC-MG. Based on these modules, the control designer can identify the signals and components that eventually require a time delay analysis, communication requirements evaluation, and cyber-attacks’ prevention strategies. Similarly, the modules of each strategy allow for analyzing the potential advantages and drawbacks of each power sharing control technique from a cyber physical perspective
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APEX and ALPS, high power density technology programs in the U.S.
In fiscal year (FY) 1998 two new fusion technology programs were initiated in the US, with the goal of making marked progress in the scientific understanding of technologies and materials required to withstand high plasma heat flux and neutron wall loads. APEX is exploring new and revolutionary concepts that can provide the capability to extract heat efficiently from a system with high neutron and surface heat loads while satisfying all the fusion power technology requirements and achieving maximum reliability, maintainability, safety, and environmental acceptability. ALPS program is evaluating advanced concepts including liquid surface limiters and divertors on the basis of such factors as their compatibility with fusion plasma, high power density handling capabilities, engineering feasibility, lifetime, safety and R and D requirements. The APEX and ALPS are three-year programs to specify requirements and evaluate criteria for revolutionary approaches in first wall, blanket and high heat flux component applications. Conceptual design and analysis of candidate concepts are being performed with the goal of selecting the most promising first wall, blanket and high heat flux component designs that will provide the technical basis for the initiation of a significant R and D effort beginning in FY2001. These programs are also considering opportunities for international collaborations
Reversible and Irreversible Interactions of Poly(3-hexylthiophene) with Oxygen Studied by Spin-Sensitive Methods
Understanding of degradation mechanisms in polymer:fullerene
bulk-heterojunctions on the microscopic level aimed at improving their
intrinsic stability is crucial for the breakthrough of organic photovoltaics.
These materials are vulnerable to exposure to light and/or oxygen, hence they
involve electronic excitations. To unambiguously probe the excited states of
various multiplicities and their reactions with oxygen, we applied combined
magneto-optical methods based on multifrequency (9 and 275 GHz) electron
paramagnetic resonance (EPR), photoluminescence (PL), and PL-detected magnetic
resonance (PLDMR) to the conjugated polymer poly(3-hexylthiophene) (P3HT) and
polymer:fullerene bulk heterojunctions (P3HT:PCBM; PCBM =
[6,6]-phenyl-C61-butyric acid methyl ester). We identified two distinct
photochemical reaction routes, one being fully reversible and related to the
formation of polymer:oxygen charge transfer complexes, the other one,
irreversible, being related to the formation of singlet oxygen under
participation of bound triplet excitons on the polymer chain. With respect to
the blends, we discuss the protective effect of the methanofullerenes on the
conjugated polymer bypassing the triplet exciton generation
Short-term forecasting of the prevalence of clinical trachoma: utility of including delayed recovery and tests for infection.
BACKGROUND: The World Health Organization aims to control blinding trachoma by 2020. Decisions on whether to start and stop mass treatments and when to declare that control has been achieved are currently based on clinical examination data generated in population-based surveys. Thresholds are based on the district-level prevalence of trachomatous inflammation-follicular (TF) in children aged 1-9 years. Forecasts of which districts may and may not meet TF control goals by the 2020 target date could affect resource allocation in the next few years. METHODS: We constructed a hidden Markov model fit to the prevalence of two clinical signs of trachoma and PCR data in 24 communities from the recent PRET-Niger trial. The prevalence of TF in children in each community at 36Â months was forecast given data from earlier time points. Forecasts were scored by the likelihood of the observed results. We assessed whether use of TF with additional TI and PCR data rather than just the use of TF alone improves forecasts, and separately whether incorporating a delay in TF recovery is beneficial. RESULTS: Including TI and PCR data did not significantly improve forecasts of TF. Forecasts of TF prevalence at 36Â months by the model with the delay in TF recovery were significantly better than forecasts by the model without the delay in TF recovery (pâ=â0.003). A zero-inflated truncated normal observation model was better than a truncated normal observation model, and better than a sensitivity-specificity observation model. CONCLUSION: The results in this study suggest that future studies could consider using just TF data for forecasting, and should include a delay in TF recovery. TRIAL REGISTRATION: Clinicaltrials.gov NCT00792922
Phenotypic cha- racterization of pig genetic resources in the departments of Oueme and Plateau in Benin
LâĂ©levage porcin est trĂšs pratiquĂ© au Sud-BĂ©nin et implique une diversitĂ© de races ou de populations. Lâobjectif de lâĂ©tude Ă©tait de caractĂ©riser les diffĂ©rents porcs sur le plan morphomĂ©trique et phĂ©notypique. Ainsi, les donnĂ©es phĂ©no- typiques ont Ă©tĂ© collectĂ©es sur 149 porcs, dont 14 amĂ©liorĂ©s, 91 croisĂ©s et 44 locaux. Les porcs de type gĂ©nĂ©tique local ont prĂ©sentĂ© des mesures morpho- logiques significativement infĂ©rieures (p < 0,05) Ă celles des porcs amĂ©liorĂ©s et des animaux issus des croisements entre les porcs amĂ©liorĂ©s et les porcs locaux. Les poils des porcs locaux Ă©taient significativement plus courts (p < 0,05) que ceux des porcs amĂ©liorĂ©s et des croisĂ©s. La couleur de la robe a variĂ© dâun type gĂ©nĂ©tique Ă lâautre. La couleur la plus rencontrĂ©e a Ă©tĂ© le blanc uniforme, suivi du noir uniforme chez tous les types gĂ©nĂ©tiques. Le profil de la tĂȘte Ă©tait plus rectiligne chez les porcs locaux, et plus concave chez les porcs amĂ©liorĂ©s et chez les croisĂ©s. Les oreilles dressĂ©es Ă©taient moins observĂ©es chez les croisĂ©s. Elles Ă©taient orientĂ©es vers lâavant chez les porcs amĂ©liorĂ©s et chez les croisĂ©s alors quâelles Ă©taient dressĂ©es et orientĂ©es vers lâarriĂšre chez les porcs locaux. La queue en tire-bouchon a Ă©tĂ© significativement (p < 0,05) plus prĂ©sente chez les porcs amĂ©liorĂ©s que chez les porcs croisĂ©s, et elle a Ă©tĂ© plus prĂ©sente chez ces derniers que chez les porcs locaux. La ligne dorsale droite a Ă©tĂ© davantage observĂ©e chez les porcs locaux et chez les croisĂ©s que chez les porcs amĂ©lio- rĂ©s chez lesquels la ligne Ă©tait plus creuse. Les porcs croisĂ©s ont prĂ©sentĂ© une grande similaritĂ© avec les porcs amĂ©liorĂ©s
The proton radius puzzle
High-precision measurements of the proton radius from laser spectroscopy of
muonic hydrogen demonstrated up to six standard deviations smaller values than
obtained from electron-proton scattering and hydrogen spectroscopy. The status
of this discrepancy, which is known as the proton radius puzzle will be
discussed in this paper, complemented with the new insights obtained from
spectroscopy of muonic deuterium.Comment: Moriond 2017 conference, 8 pages, 4 figure
CAD-centric Computation Management System for a Virtual TBM
HyPerComp Inc. in research collaboration with TEXCEL has set out to build a Virtual Test Blanket Module (VTBM) computational system to address the need in contemporary fusion research for simulating the integrated behavior of the blanket, divertor and plasma facing components in a fusion environment. Physical phenomena to be considered in a VTBM will include fluid flow, heat transfer, mass transfer, neutronics, structural mechanics and electromagnetics. We seek to integrate well established (third-party) simulation software in various disciplines mentioned above. The integrated modeling process will enable user groups to interoperate using a common modeling platform at various stages of the analysis. Since CAD is at the core of the simulation (as opposed to computational meshes which are different for each problem,) VTBM will have a well developed CAD interface, governing CAD model editing, cleanup, parameter extraction, model deformation (based on simulation,) CAD-based data interpolation. In Phase-I, we built the CAD-hub of the proposed VTBM and demonstrated its use in modeling a liquid breeder blanket module with coupled MHD and structural mechanics using HIMAG and ANSYS. A complete graphical user interface of the VTBM was created, which will form the foundation of any future development. Conservative data interpolation via CAD (as opposed to mesh-based transfer), the regeneration of CAD models based upon computed deflections, are among the other highlights of phase-I activity
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