386 research outputs found
A model proposal for the electric energy valorization in a pv power plant equipped with CAES system
In this article, an analytical method is evaluated and implemented; to assess the possible electricity sales strate-gies produced by a 3 MW photovoltaic power plant, connected to a 250 kW CAES (Compressed Air Energy Storage) system, with a storage capacity of 750 kWh. The presented model combines a different numbers of parameters and variables, relevant for the system optimization. Several simulations of various system configu-rations have been carried out, to explore and evaluate the economic and technical feasibility of the plant, spe-cifically it has been valued tow case of study: CASE 1 the system is not incentive; CASE 2 the system is incen-tive. In the end of paper it has been rated the Leveled Cost of Energy (LCOE) and specified how the investment could become affordable in the foreseeable future
Comparison between 1-D and grey-box models of a SOFC
Solid Oxide Fuel Cells (SOFCs) have shown unique performance in terms of greater electrical efficiency and thermochemical integrity with the power systems compared to gas turbines and internal combustion engines. Nonetheless, simple and reliable models still must be defined. In this paper, a comparison between a grey-box model and a 1-D model of a SOFC is performed to understand the impact of the heat transfer inside the cell on the internal temperature distribution of the solid electrolyte. Hence, a significant internal temperature peak of the solid electrolyte is observed for a known difference between anode and cathode inlet temperatures. Indeed, it highlights the difference between the 1-D model and the grey-box model regarding the thermal conditioning of the SOFC. Therefore, the results of this study can be used to investigate the reliability of the thermal results of box models in system-level simulations
From 3-geometry transition amplitudes to graviton states
18 pagesIn various background independent approaches, quantum gravity is defined in terms of a field propagation kernel: a sum over paths interpreted as a transition amplitude between 3-geometries, expected to project quantum states of the geometry on the solutions of the Wheeler-DeWitt equation. We study the relation between this formalism and conventional quantum field theory methods. We consider the propagation kernel of 4d Lorentzian general relativity in the temporal gauge, defined by a conventional formal Feynman path integral, gauge fixed Ă la Fadeev-Popov. If space is compact, this turns out to depend only on the initial and final 3-geometries, while in the asymptotically flat case it depends also on the asymptotic proper time. We compute the explicit form of this kernel at first order around flat space, and show that it projects on the solutions of all quantum constraints, including the Wheeler-DeWitt equation, and yields the correct vacuum and n-graviton states. We also illustrate how the Newtonian interaction is coded into the propagation kernel, a key open issue in the spinfoam approach
Reti di trasporto nazionale e concorrenza nei mercati del gas: il caso Eni-Snam Rete Gas
In transposing EU Directive 73/2009/CE on natural gas infrastructures into Italy’s national legislation, the country opted for a Independent Transmission Operator (ITO) model instead of full ownership unbundling. ITO allows the essential facility to be controlled by a vertically integrated incumbent who is also in charge of choosing the company’s directors, even though within a strictly regulated context. Regulation applies both to the use of the infrastructure itself and information flow to and from it. This paper explores the costs and benefits of ownership unbundling in the light of the literature. The Italian case is studied by developing a simple econometric model that compares the investment policy of Snam Rete Gas – i.e. the operator of Italy’s natural gas transportation network, which is controlled by the former monopolist Eni - with that of Terna, operator of the electricity transmission grid, which has been unbundled from the formerly-vertically integrated incumbent since 2004
Nuova segretaria, solita passione: sempre altissimo l’interesse per la politica
Le primarie sono uno strumento di democratizzazione della vita interna ai partiti. Secondo le serie storiche raccolte da CLS-Candidate and Leader Selection a partire dal 2009, i selettori che partecipano a quelle del Partito Democratico hanno sempre dichiarato di avere un forte interesse per la politica. Il capitolo mette a confronto i dati dell’exit poll 2023 con quelli delle precedenti primarie, andando alla ricerca di un possibile “effetto Schlein” su questo aspetto. L’attrazione della candidata autorizzava a ipotizzare un afflusso di selettori ad personam eventualmente poco interessati alla politica. L’evidenza empirica conferma invece un persistente elevato interesse per la politica da parte del selettorato nel suo complesso, e un dato addirittura più alto per la parte che ha votato Schlein. Anche con la nuova leadership, permangono i dubbi sulla capacità del PD di attirare nell’immediato futuro categorie di cittadini meno sofisticati
Reti di trasporto nazionale e concorrenza nei mercati del gas: il caso Eni-Snam Rete Gas
In transposing EU Directive 73/2009/CE on natural gas infrastructures into Italy’s national legislation, the country opted for a Independent Transmission Operator (ITO) model instead of full ownership unbundling. ITO allows the essential facility to be controlled by a vertically integrated incumbent who is also in charge of choosing the company’s directors, even though within a strictly regulated context. Regulation applies both to the use of the infrastructure itself and information flow to and from it. This paper explores the costs and benefits of ownership unbundling in the light of the literature. The Italian case is studied by developing a simple econometric model that compares the investment policy of Snam Rete Gas – i.e. the operator of Italy’s natural gas transportation network, which is controlled by the former monopolist Eni - with that of Terna, operator of the electricity transmission grid, which has been unbundled from the formerly-vertically integrated incumbent since 2004
Partial Discharge alert system in medium voltage switchgear
Partial discharge (PD) is a well-known indicator of insulation problems in high voltage equipment. We report on experience collected during the development of a new online PD detection and alert system for air insulated switchgear (AIS) installed base. The approach taken to integrate the sensor with minimal retrofit effort and operational disruption is described. Results from a test setup including a line-up of panels and different reference PD sources in comparison to a commercial PD system are presented. The effect of cables connected to the switchgear is investigated by testing the system including additional capacitive load and using a simulation for a typical geometry. We also address the question regarding the design of an alert system to be used in connection with the continuous data acquisition
Intrarater and Inter-rater Reliability of Active Cervical Range of Motion in Patients With Nonspecific Neck Pain Measured With Technological and Common Use Devices: A Systematic Review With Meta-regression
Objectives The purpose of this systematic review was to compare intrarater and inter-rater reliability of active cervical range of motion (ACROM) measures obtained with technological devices to those assessed with low-cost devices in patients with nonspecific neck pain. As a secondary outcome, we investigated if ACROM reliability is influenced by the plane of the assessed movement. Methods Medline, Scopus, Embase, the Cochrane Library, CINHAL, PEDro, and gray literature were searched until August 2016. Inclusion criteria were reliability design, population of adults with nonspecific neck pain, examiners of any level of experience, measures repeated at least twice, and statistical indexes on reliability. A device was considered inexpensive if it cost less than \ue2\u82\uac500. The risk of bias of included studies was assessed by Quality Appraisal of Reliability Studies. Results The search yielded 35 151 records. Nine studies met all eligibility criteria. Their Quality Appraisal of Reliability Studies mean score was 3.7 of 11. No significant effect of the type of device (inexpensive vs expensive) on intraclass correlation coefficient (ICC) was identified for intrarater (ICC = 0.93 vs 0.91; P >.99) and inter-rater reliability (ICC = 0.80 vs 0.87; P >.99). The plane of movement did not affect inter-rater reliability (P =.11). Significant influences were identified with intrarater reliability (P =.0001) of inexpensive devices, where intrarater reliability decreased (P =.01) in side bending, compared with flexion-extension. Conclusions The use of expensive devices to measure ACROM in adults with nonspecific neck pain does not seem to improve the reliability of the assessment. Side bending had a lower level of intrarater reliability
The Effect of Autologous Platelet Lysate Eye Drops: An In Vivo Confocal Microscopy Study
Purpose. To determine the effectiveness of autologous platelet lysate (APL) eye drops in patients with primary Sjögren syndrome (SS) dry eye, refractory to standard therapy, in comparison with patients treated with artificial tears. We focused on the effect of APL on cornea morphology with the in vivo confocal microscopy (IVCM). Methods. Patients were assigned to two groups: group A used autologous platelet lysate QID, and group B used preservative-free artificial tears QID, for 90 days. Ophthalmological assessments included ocular surface disease index (OSDI), best corrected visual acuity (BCVA), Schirmer test, fluorescein score, and breakup time (BUT). A subgroup of patients in group A underwent IVCM: corneal basal epithelium, subbasal nerves, Langerhans cells, anterior stroma activated keratocytes, and reflectivity were evaluated. Results. 60 eyes of 30 patients were enrolled; in group A (n=20 patients) mean OSDI, fluorescein score, and BUT showed significant improvement compared with group B (n=10 patients). The IVCM showed a significant increase in basal epithelium cells density and subbasal nerve plexus density and number and a decrease in Langerhans cells density (p<0.05). Conclusion. APL was found effective in the treatment of SS dry eye. IVCM seems to be a useful tool to visualize cornea morphologic modifications
Evaluation of the Classification Accuracy of the Kidney Biopsy Direct Immunofluorescence through Convolutional Neural Networks
Background and objectives: Immunohistopathology is an essential technique in the diagnostic workflow of a kidney biopsy. Deep learning is an effective tool in the elaboration of medical imaging. We wanted to evaluate the role of a convolutional neural network as a support tool for kidney immunofluorescence reporting.
Design, setting, participants, & measurements: High-magnification (
7400) immunofluorescence images of kidney biopsies performed from the year 2001 to 2018 were collected. The report, adopted at the Division of Nephrology of the AOU Policlinico di Modena, describes the specimen in terms of \u201cappearance,\u201d \u201cdistribution,\u201d \u201clocation,\u201d and \u201cintensity\u201d of the glomerular deposits identified with fluorescent antibodies against IgG, IgA, IgM, C1q and C3 complement fractions, fibrinogen, and \u3ba- and \u3bb-light chains. The report was used as ground truth for the training of the convolutional neural networks.
Results: In total, 12,259 immunofluorescence images of 2542 subjects undergoing kidney biopsy were collected. The test set analysis showed accuracy values between 0.79 (\u201cirregular capillary wall\u201d feature) and 0.94 (\u201cfine granular\u201d feature). The agreement test of the results obtained by the convolutional neural networks with respect to the ground truth showed similar values to three pathologists of our center. Convolutional neural networks were 117 times faster than human evaluators in analyzing 180 test images. A web platform, where it is possible to upload digitized images of immunofluorescence specimens, is available to evaluate the potential of our approach.
Conclusions: The data showed that the accuracy of convolutional neural networks is comparable with that of pathologists experienced in the field
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