2,327 research outputs found
The Pulsed Neutron Beam EDM Experiment
We report on the Beam EDM experiment, which aims to employ a pulsed cold
neutron beam to search for an electric dipole moment instead of the established
use of storable ultracold neutrons. We present a brief overview of the basic
measurement concept and the current status of our proof-of-principle Ramsey
apparatus
Analysis of photovoltaic projects in a Mediterranean island
The paper presents an analysis of the four grid-connected systems installed in Malta and monitored by the Institute for Energy Technology of the University of Malta. The systems have varying power ratings, orientation and tilts. Three systems had stationary solar modules, while the fourth one used an active tracking device. The purpose of this study was to evaluate the performance of different systems under the local weather conditions of a typical Mediterranean country. Comparison to other systems in EU countries was made and answers to frequently asked questions were found. The mean monthly Performance Ratio of the systems ranged between 0.51 and 0.80, while the final yield was reported to be between 2.76kWh/kWp/day and 3.61kWh/kWp/day. The final efficiency was also found to be between 5.1% and 7.1%. This compared favourably with results reported by European researchers such as in the Thermie Project. The inverters proved to be safe and did respond as expected during times of grid disturbance. In view of Malta’s new membership in the European Union, this study will be an essential tool to support future widespread applications of solar electric systems in Malta.peer-reviewe
Geographical interdependence, international trade and economic dynamics: the Chinese and German solar energy industries
The trajectories of the German and Chinese photovoltaic industries differ significantly yet are strongly interdependent. Germany has seen a rapid growth in market demand and a strong increase in production, especially in the less developed eastern half of the country. Chinese growth has been export driven. These contrasting trajectories reflect the roles of market creation, investment and credit and the drivers of innovation and competitiveness. Consequent differences in competiveness have generated major trade disputes
Hybrid Biomass-Wind Power Plant For Reliable Energy Generation
[EN] Massive implementation of renewable energy resources is a key element to reduce CO2 emissions associated to electricity generation. Wind resources can provide an important alternative to conventional electricity generation mainly based on fossil fuels.
However, wind generators are greatly affected by the restrictive operating rules of electricity markets because, as wind is naturally variable, wind generators may have serious difficulties on submitting accurate generation schedules on a day ahead basis, and on complying with scheduled obligations in real-time operation.
In this paper, an innovative system combining a biomass gasification power plant, a gas storage system and stand-by generators to stabilize a generic 40 MW wind park is proposed and evaluated with real data. The wind park power production model is based on real data about power production of a Spanish wind park and a probabilistic approach to quantify fluctuations and so, power compensation needs. The hybrid wind-biomass system is analysed to obtain main hybrid system design parameters. This hybrid system can mitigate wind prediction errors and so provide a predictable source of electricity.
An entire year cycle of hourly power compensations needs has been simulated deducing storage capacity, extra power needs of the biomass power plant and stand-by generation capacity to assure power compensation during critical peak hours with acceptable reliability.Pérez-Navarro, A.; Alfonso-Solar, D.; Álvarez, C.; Ibáñez, F.; Sánchez-Diaz, C.; Segura Heras, I. (2010). Hybrid Biomass-Wind Power Plant For Reliable Energy Generation. Renewable Energy. 35(7):1436-1443. https://doi.org/10.1016/j.renene.2009.12.0181436144335
SAT-Based Synthesis Methods for Safety Specs
Automatic synthesis of hardware components from declarative specifications is
an ambitious endeavor in computer aided design. Existing synthesis algorithms
are often implemented with Binary Decision Diagrams (BDDs), inheriting their
scalability limitations. Instead of BDDs, we propose several new methods to
synthesize finite-state systems from safety specifications using decision
procedures for the satisfiability of quantified and unquantified Boolean
formulas (SAT-, QBF- and EPR-solvers). The presented approaches are based on
computational learning, templates, or reduction to first-order logic. We also
present an efficient parallelization, and optimizations to utilize reachability
information and incremental solving. Finally, we compare all methods in an
extensive case study. Our new methods outperform BDDs and other existing work
on some classes of benchmarks, and our parallelization achieves a super-linear
speedup. This is an extended version of [5], featuring an additional appendix.Comment: Extended version of a paper at VMCAI'1
Assessment of morbidity in gynaecologic oncology laparoscopy and identification of possible risk factors
BACKGROUND: The aim of this study was to ascertain the incidence of and the risk factors associated with morbidity in laparoscopy performed on patients with cervical cancer and endometrial cancer. METHODS: This was an observational study of a cohort of 128 women, 89 with endometrial cancer and 39 with cervical cancer from January 2000 to December 2011. We used the Student's t-test or the Mann-Whitney U test for continuous variables, and the Chi-square or Fisher's exact test for categorical variables. RESULTS: Complications were found in 44 patients (34.4%). After a multivariate analysis, among the risk factors associated with the presence of complications as the only type of surgery was found to be statistically significant (p = 0.043), more frequent in the most complex procedures such as Wertheim operation, trachelectomy, and para-aortic lymphadenectomy. Type of surgery (p = 0.003) and tumour type (p = 0.003) were risk factors associated with conversion to laparotomy. It was more frequent among the most complex procedures and cervical cancer cases. Regarding the need for transfusion, significant differences were observed in terms of surgery duration (p < 0.001), more frequent in longer surgery. CONCLUSION: Morbidity in laparoscopic surgical oncology is related to the surgery complexity, where the basal characteristics of the patient are not a factor of influence in the development of complications
Analysis of the Visual Appearance of AISI 430 Ferritic Stainless Steel Flat Sheets Manufactured by Cool Rolling and Bright Annealing
This article reports on the relation between the surface topography and the optical reflectance,
both total and diffuse, of different samples of AISI 430 ferritic stainless steel. Gaussian
filters with different cutoff wavelengths were applied to the height maps of the surface topography of
the samples, to separate the different scales of surface roughness involved in optical scattering in the
visible range of the spectrum. Significant anisotropy, related to the rolling process, was found in the
topography. An effective roughness slope parameter was defined from the dependence of the ratio
between the root mean square height and the autocorrelation length on the cutoff wavelength. This
roughness slope demonstrated an exceptionally good linear relationship with CIE 1931 luminance,
which was calculated from the diffuse reflection spectra. The color uniformity of the samples was
analyzed based on their CIE L*a*b* coordinates under daylight and LED illumination. The results
confirmed the strong influence of manufacturing process on the surface characteristics of AISI 430
ferritic stainless steel sheet products with a bright finish.This work was co-financed by the 2014-2020 ERDF Operational Programme and by the Department of Economy, Knowledge, Business and University of the Regional Government of Andalusia. Project reference: FEDER-UCA18-106321
Are solar neutrino oscillations robust?
The robustness of the large mixing angle (LMA) oscillation (OSC)
interpretation of the solar neutrino data is considered in a more general
framework where non-standard neutrino interactions (NSI) are present. Such
interactions may be regarded as a generic feature of models of neutrino mass.
The 766.3 ton-yr data sample of the KamLAND collaboration are included in the
analysis, paying attention to the background from the reaction ^13C(\alpha,n)
^16O. Similarly, the latest solar neutrino fluxes from the SNO collaboration
are included. In addition to the solution which holds in the absence of NSI
(LMA-I) there is a 'dark-side' solution (LMA-D) with sin^2 theta_Sol = 0.70,
essentially degenerate with the former, and another light-side solution (LMA-0)
allowed only at 97% CL. More precise KamLAND reactor measurements will not
resolve the ambiguity in the determination of the solar neutrino mixing angle
theta_Sol, as they are expected to constrain mainly Delta m^2. We comment on
the complementary role of atmospheric, laboratory (e.g. CHARM) and future solar
neutrino experiments in lifting the degeneracy between the LMA-I and LMA-D
solutions. In particular, we show how the LMA-D solution induced by the
simplest NSI between neutrinos and down-type-quarks-only is in conflict with
the combination of current atmospheric data and data of the CHARM experiment.
We also mention that establishing the issue of robustness of the oscillation
picture in the most general case will require further experiments, such as
those involving low energy solar neutrinos.Comment: 13 pages, 6 figures; Final version to appear in JHE
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