726 research outputs found
Current, Projected Performance and Costs of Thermal Energy Storage
The technology for storing thermal energy as sensible heat, latent heat, or thermochemical energy has greatly evolved in recent years, and it is expected to grow up to about 10.1 billion US dollars by 2027. A thermal energy storage (TES) system can significantly improve industrial energy efficiency and eliminate the need for additional energy supply in commercial and residential applications. This study is a first-of-its-kind specific review of the current projected performance and costs of thermal energy storage. This paper presents an overview of the main typologies of sensible heat (SH-TES), latent heat (LH-TES), and thermochemical energy (TCS) as well as their application in European countries. With regard to future challenges, the installation of TES systems in buildings is being implemented at a rate of 5%; cogeneration application with TES is attested to 10.2%; TES installation in the industry sector accounts for 5% of the final energy consumption. From the market perspective, the share of TES is expected to be dominated by SH-TES technologies due to their residential and industrial applications. With regard to the cost, the SH-TES system is typically more affordable than the LH-TES system or the TCS system because it consists of a simple tank containing the medium and the charging/discharging equipment
Renewable sources urban cells microgrid. A case study
Nowadays, microgrid technologies play a relevant role in the research field as well as in the commercial market. The opportunity to provide electricity in wide areas without using centralized electrical infrastructure networks is a reliable key for achieving the European Union sustainability goals. In this regard, the proposed research aims at describing an electric microgrid configuration powered by a photovoltaic system, supplying three school buildings located in the center of Italy. Additionally, the resilience theme is deeply investigated, analyzing the use of an emergency generator system (EGS) in case of electric grid blackouts. MATLAB/Simulink was chosen to simulate the users’ energy demand as well as to calculate the microgrid performance. Results show that almost the total consumption of the microgrid is covered by the photovoltaic system, and the use of an EGS allows energy resilience and moderate economic savings for the communit
The pseudobulge of NGC 1292
The photometric and kinematic properties of Sb NGC 1292 suggest it hosts a
pseudobulge. The properties of the stellar population of such a pseudobulge are
consistent with a slow buildup within a scenario of secular evolution.Comment: 2 pages, 1 figure to appear in the proceedings of "Formation and
Evolution of Galaxy Disks", Rome, October 2007, Eds. J. Funes and E. M.
Corsin
Kinematic and stellar population properties of the counter-rotating components in the S0 galaxy NGC 1366
Context. Many disk galaxies host two extended stellar components that rotate in opposite directions. The analysis of the stellar populations of the counter-rotating components provides constraints on the environmental and internal processes that drive their formation. Aims. The S0 NGC 1366 in the Fornax cluster is known to host a stellar component that is kinematically decoupled from the main body of the galaxy. Here we successfully separated the two counter-rotating stellar components to independently measure the kinematics and properties of their stellar populations. Methods. We performed a spectroscopic decomposition of the spectrum obtained along the galaxy major axis and separated the relative contribution of the two counter-rotating stellar components and of the ionized-gas component. We measured the line-strength indices of the two counter-rotating stellar components and modeled each of them with single stellar population models that account for the \u3b1/Fe overabundance. Results. We found that the counter-rotating stellar component is younger, has nearly the same metallicity, and is less \u3b1/Fe enhanced than the corotating component. Unlike most of the counter-rotating galaxies, the ionized gas detected in NGC 1366 is neither associated with the counter-rotating stellar component nor with the main galaxy body. On the contrary, it has a disordered distribution and a disturbed kinematics with multiple velocity components observed along the minor axis of the galaxy. Conclusions. The different properties of the counter-rotating stellar components and the kinematic peculiarities of the ionized gas suggest that NGC 1366 is at an intermediate stage of the acquisition process, building the counter-rotating components with some gas clouds still falling onto the galaxy. \ua9 ESO 2017
Liberal or restricted fluid administration: are we ready for a proposal of a restricted intraoperative approach?
SUGAMMADEX versus neostigmine after ROCURONIUM continuous infusion in patients undergoing liver transplantation
Background: Rapid neuromuscular block reversal at the end of major abdominal surgery is recommended to avoid any postoperative residual block. To date, no study has evaluated sugammadex performance after rocuronium administration in patients undergoing liver transplantation. This is a randomized controlled trial with the primary objective of assessing the neuromuscular transmission recovery time obtained with sugammadex versus neostigmine after rocuronium induced neuromuscular blockade in patients undergoing orthotopic liver transplantation. Methods: The TOF-Watch SX\uae, calibrated and linked to a portable computer equipped with TOF-Watch SX Monitor Software\uae, was used to monitor and record intraoperative neuromuscular block maintained with a continuous infusion of rocuronium. Anaesthetic management was standardized as per our institution's internal protocol. At the end of surgery, neuromuscular moderate block reversal was obtained by administration of 2 mg/kg of sugammadex or 50 mcg/kg of neostigmine (plus 10 mcg/kg of atropine). Results: Data from 41 patients undergoing liver transplantation were analysed. In this population, recovery from neuromuscular block was faster following sugammadex administration than neostigmine administration, with mean times\ub1SD of 9.4 \ub1 4.6 min and 34.6 \ub1 24.9 min, respectively (p < 0.0001). Conclusion: Sugammadex is able to reverse neuromuscular block maintained by rocuronium continuous infusion in patients undergoing liver transplantation. The mean reversal time obtained with sugammadex was significantly faster than that for neostigmine. It is important to note that the sugammadex recovery time in this population was found to be considerably longer than in other surgical settings, and should be considered in clinical practice. Trial registration: ClinicalTrials.gov NCT02697929 (registered 3rd March 2016)
The XXL Survey VIII: MUSE characterisation of intracluster light in a z0.53 cluster of galaxies
Within a cluster, gravitational effects can lead to the removal of stars from
their parent galaxies. Gas hydrodynamical effects can additionally strip gas
and dust from galaxies. The properties of the ICL can therefore help constrain
the physical processes at work in clusters by serving as a fossil record of the
interaction history. The present study is designed to characterise this ICL in
a ~10^14 M_odot and z~0.53 cluster of galaxies from imaging and spectroscopic
points of view. By applying a wavelet-based method to CFHT Megacam and WIRCAM
images, we detect significant quantities of diffuse light. These sources were
then spectroscopically characterised with MUSE. MUSE data were also used to
compute redshifts of 24 cluster galaxies and search for cluster substructures.
An atypically large amount of ICL has been detected in this cluster. Part of
the detected diffuse light has a very weak optical stellar component and
apparently consists mainly of gas emission, while other diffuse light sources
are clearly dominated by old stars. Furthermore, emission lines were detected
in several places of diffuse light. Our spectral analysis shows that this
emission likely originates from low-excitation parameter gas. The stellar
contribution to the ICL is about 2.3x10^9 yrs old even though the ICL is not
currently forming a large number of stars. On the other hand, the contribution
of the gas emission to the ICL in the optical is much greater than the stellar
contribution in some regions, but the gas density is likely too low to form
stars. These observations favour ram pressure stripping, turbulent viscous
stripping, or supernovae winds as the origin of the large amount of
intracluster light. Since the cluster appears not to be in a major merging
phase, we conclude that ram pressure stripping is the most plausible process
that generates the observed ICL sources.Comment: Accepted in A&A, english enhanced, figure location different than in
the A&A version due to different style files, shortened abstrac
Phantom model and scoring system to assess ability in ultrasound-guided chest drain positioning
Background: Chest tube positioning is an invasive procedure associated with potentially serious injuries. In the last few years, we have been running a project directed at developing a practical simulator of a surgical procedure taught on our medical training program. The phantom model reconstructs the pleural anatomy, visible by lung ultrasound, used for the assessed performance of the Seldinger technique. The aim of the present study was to investigate the validity of this simulation technology for assessing residents in anesthesia and intensive care medicine; specifically, their skill in positioning a US-guided chest tube drain was tested using the simulator device. The second aim of the paper was to evaluate the learning curve of our residents over their 5-year study course and validate the phantom scoring system. Methods: This was a prospective, single-blinded observational study. Participants were recruited from residents in anesthesia and intensive care medicine and divided into two groups: \u2018Novice\u2019 and \u2018Expert,\u2019 based on the course year attended (years 1, 2, and 3 vs. years 4 and 5, respectively). We asked them to position a chest tube drain in a phantom model, guided by ultrasound, to drain a simulated pleural effusion. Each subject performed two tests that simulated pleural effusions of 4 and 2\ua0cm, respectively. Every step of the maneuver was constantly monitored and the performance scored by the investigators. We then performed a Spearman correlation analysis to evaluate the effect of experience level on the performance of the two groups of residents. Results: Thirty-one residents were included in this study: 20 in the Novice group and 11 in the Expert group. The mean performance rating score was 0.75\ua0\ub1\ua04.38 for the Novice Group and 5.91\ua0\ub1\ua03.75 for the Expert group (p\ua0=\ua00.0026). The Spearman correlation analysis examining the relationship between year of residency and performance rating score confirmed a positive correlation (r\ua0=\ua00.58, p\ua0=\ua00.0006). Post-test trend analysis revealed a statistically significant linear trend for skill growth across time, i.e., course year (p\ua0=\ua00.0022). Conclusions: Our simulated procedure using a phantom model of lung anatomy can accurately and reliably be used to assess the skill levels of operators in their ability to drain pleural effusion
Comparison of stroke volume changes of LiDCO™plus and Flotrac™ during postoperative hemodynamic optimization
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