The Impact of Aortic Occlusion Balloon on Mortality After Endovascular Repair of Ruptured Abdominal Aortic Aneurysms: A Meta-analysis and Meta-regression Analysis

INTRODUCTION:We aimed to investigate whether the use of aortic occlusion balloon (AOB) has an impact on mortality of patients undergoing endovascular repair of ruptured abdominal aortic aneurysms (RAAAs).METHODS:A meta-analysis of the English-language literature was undertaken through February 2013. Articles reporting data on outcome after endovascular repair of RAAAs were identified and information regarding the use of AOB was sought.RESULTS:Included in this meta-analysis were 39 eligible studies reporting 1277 patients. The pooled perioperative mortality was 21.6% (95% CI 18.1-25.1%). There was significant within-study heterogeneity (I(2) 50.2%, P < 0.001). A total of 200 patients required AOB with an estimated pooled proportion of 14.1% (8.9-19.3%). Individual random-effects meta-regression investigating the effect of AOB and other risk factors on mortality revealed a significant linear association of hemodynamic instability, bifurcated endograft approach, and primary conversion to open repair with mortality and a nonlinear (second degree polynomial) association of AOB with mortality. On multivariable meta-regression models, both hemodynamic instability and AOB were found to be statistically significant, independent predictors of mortality. In particular, there was a statistically significant negative correlation between AOB and mortality and a positive effect of hemodynamic instability on mortality. In practical terms, mortality was significantly higher in studies with a higher proportion of hemodynamically unstable patients and lower in studies with a higher rate of AOB use.CONCLUSION:This study provides meta-analytical evidence that the use of an AOB in unstable RAAA patients undergoing endovascular repair may improve the results

Protect the natives to combat the aliens: Could octopus vulgaris cuvier, 1797 be a natural agent for the control of the lionfish invasion in the mediterranean sea?

[No abstract available

Systematic solar pvt testing in steady-state and dynamic outdoor conditions

In order to predict accurately the performance of solar-thermal or hybrid PVT systems, it is necessary that the steady-state and dynamic performance of the collectors is understood. This work focuses on the testing and detailed characterization of nonconcentrating PVT collectors based on the testing procedure specified in the European standard EN 12975-2. Three different types of PVT collectors were tested in Cyprus under outdoor conditions similar to those specified in the standard. Amongst other results, we show that that poor thermal contact between the laminate and the copper absorber can lead to a significant deterioration in thermal performance and that a glass cover improves the thermal performance by reducing losses as expected, but causes electrical losses that vary with the glass transmittance and the incident angle. It is found that the reduction in electrical efficiency at large solar incidence angles is more significant than that due to elevated temperatures representative of water heating applications. Dynamic tests are performed by imposing a step change in incident irradiance in order to quantify the collector time constant and effective heat capacity. A time constant of 8 min is found for a commercial PVT module, which compares to <2 min for a flat plate solar collector. The PVT collector time constant is found to be very sensitive to the thermal contact between the PV layer and the absorber, which may vary according to the quality of construction, and also to the operating flow rate.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers

A review of solar hybrid photovoltaic-thermal (PV-T) collectors and systems

In this paper, we provide a comprehensive overview of the state-of-the-art in hybrid PV-T collectors and the wider systems within which they can be implemented, and assess the worldwide energy and carbon mitigation potential of these systems. We cover both experimental and computational studies, identify opportunities for performance enhancement, pathways for collector innovation, and implications of their wider deployment at the solar-generation system level. First, we classify and review the main types of PV-T collectors, including air-based, liquid-based, dual air–water, heat-pipe, building integrated and concentrated PV-T collectors. This is followed by a presentation of performance enhancement opportunities and pathways for collector innovation. Here, we address state-of-the-art design modifications, next-generation PV cell technologies, selective coatings, spectral splitting and nanofluids. Beyond this, we address wider PV-T systems and their applications, comprising a thorough review of solar combined heat and power (S–CHP), solar cooling, solar combined cooling, heat and power (S–CCHP), solar desalination, solar drying and solar for hydrogen production systems. This includes a specific review of potential performance and cost improvements and opportunities at the solar-generation system level in thermal energy storage, control and demand-side management. Subsequently, a set of the most promising PV-T systems is assessed to analyse their carbon mitigation potential and how this technology might fit within pathways for global decarbonization. It is estimated that the REmap baseline emission curve can be reduced by more than 16% in 2030 if the uptake of solar PV-T technologies can be promoted. Finally, the review turns to a critical examination of key challenges for the adoption of PV-T technology and recommendations

Plasma assisted bio-degradation of poly-lactic acid (PLA)

Plastics are artificial synthetic organic polymers that have been used in every area of daily life. However, because of their slow degradation rate, their use is contentious. The treatment of the surface of the sample is considered necessary as enzymatic or bacterial attach is not possible, if the plastic surface environment is not ideal. The main topic of this work is the investigation of the effect of atmospheric dielectric barrier discharge (DBD) plasma on the near surface structure of polylactic acid (PLA) samples, which, in turn, can promote the adhesion of enzymes or bacteria for further biodegradation. In general, plasma processes can already be considered as inherently environmental technologies. Plasma processes enable resource saving through high energy utilization efficiency and thus, are environ-mentally friendly technologies. Atmospheric pressure discharges (APDs) are useful because of their specific advantages over low-pressure ones. They do not need expensive vacuum equipment, and generate nonthermal plasmas, which are more suitable for assembly line processes. Hence, this category of discharges has significant industrial applications. The use of a dielectric barrier in the discharge gap helps prevent spark formation. DBDs exhibit two major discharge modes: filamentary and glow (homogeneous). The glow discharge mode has obvious advantages over the filamentary one for applications such as treatment of surfaces and deposition of thin films. Glow mode discharges with average power densities comparable to those of filamentary discharges are of enormous interest for applications in which reliable control is required. Here we will present the increased adhesion of bacteria strains on DBD plasma treated PLA foils which can lead to a better degradation of the PLA. X-ray photoelectron spectroscopy (XPS) measurements of the foils prior to and after the treatment proved the changes on the polymer surface. A short discussion of the possibilities the treatment opens is given.CHANIA 2023: 10th International Conference on Sustainable Solid Waste Management Chania, Greece, 21 - 24 JUNE 202

Protect the Natives to Combat the Aliens: Could Octopus vulgaris Cuvier, 1797 Be a Natural Agent for the Control of the Lionfish Invasion in the Mediterranean Sea?

Biological invasions constitute a major threat to native ecosystems and to global biodiversity [...]</jats:p

High coercivity cobalt carbide nanoparticles processed via polyol reaction: A new permanent magnet material

Cobalt carbide nanoparticles were processed using polyol reduction chemistry that offers high product yields in a cost effective single-step process. Particles are shown to be acicular in morphology and typically assembled as clusters with room temperature coercivities greater than 4 kOe and maximum energy products greater than 20 KJ/m3. Consisting of Co3C and Co2C phases, the ratio of phase volume, particle size, and particle morphology all play important roles in determining permanent magnet properties. Further, the acicular particle shape provides an enhancement to the coercivity via dipolar anisotropy energy as well as offering potential for particle alignment in nanocomposite cores. While Curie temperatures are near 510K at temperatures approaching 700 K the carbide powders experience an irreversible dissociation to metallic cobalt and carbon thus limiting operational temperatures to near room temperature.Comment: Total 28 pages, 10 figures, and 1 tabl

Cyprus building energy performance methodology: A comparison of the calculated and measured energy consumption results

In order to fulfil article 4 of the 2002/91/EC Directive (EPBD) a national methodology for the energy performance of buildings was drafted and approved by the Government of Cyprus in 2009. This methodology is in line with the European standards prepared to facilitate EPBD implementation and follows the asset rating approach that is, it represents the intrinsic annual energy use of a building under standardised conditions. CEN standards leave an option, quite suitable for existing and complex buildings, for operational rating, which is an energy rating based on measured amounts of delivered and exported energy. The calculated and measured rating exhibit advantages and disadvantages and as expected the results of the two approaches vary, since the measured rating approach takes into account the effect of user behaviour, the actual weather conditions and the realized (actual) thermal comfort conditions inside the building. This paper presents the Cyprus legal framework for adopting the EPBD and exhibits the Cyprus methodology for the energy performance of buildings. Moreover the advantages and disadvantages of the asset and operational rating approaches are discussed and a comparison of the results of these two approaches for a selected number of dwellings is presented. One of these cases is also examined with respect to the climatic conditions, by changing the climatic zone in which the building is erected. The latter reveals the effect of climate on the calculated energy requirements of the building for both heating and cooling

A review of solar hybrid photovoltaic-thermal (PV-T) collectors and systems

In this paper, we provide a comprehensive overview of the state-of-the-art in hybrid PV-T collectors and the wider systems within which they can be implemented, and assess the worldwide energy and carbon mitigation potential of these systems. We cover both experimental and computational studies, identify opportunities for performance enhancement, pathways for collector innovation, and implications of their wider deployment at the solar-generation system level. First, we classify and review the main types of PV-T collectors, including air-based, liquid-based, dual air–water, heat-pipe, building integrated and concentrated PV-T collectors. This is followed by a presentation of performance enhancement opportunities and pathways for collector innovation. Here, we address state-of-the-art design modifications, next-generation PV cell technologies, selective coatings, spectral splitting and nanofluids. Beyond this, we address wider PV-T systems and their applications, comprising a thorough review of solar combined heat and power (S–CHP), solar cooling, solar combined cooling, heat and power (S–CCHP), solar desalination, solar drying and solar for hydrogen production systems. This includes a specific review of potential performance and cost improvements and opportunities at the solar-generation system level in thermal energy storage, control and demand-side management. Subsequently, a set of the most promising PV-T systems is assessed to analyse their carbon mitigation potential and how this technology might fit within pathways for global decarbonization. It is estimated that the REmap baseline emission curve can be reduced by more than 16% in 2030 if the uptake of solar PV-T technologies can be promoted. Finally, the review turns to a critical examination of key challenges for the adoption of PV-T technology and recommendations

Investigation of the parameters affecting the thermosiphonic phenomenon in solar water heaters

Cyprus is currently the leading country in the world with respect to the application of solar water heaters for domestic applications, with more than 93% of the houses equipped with such a system. The great majority of these solar water heaters are of the thermosiphonic type. Thermosiphonic is a natural phenomenon where the flow of the solar heated water from the collector to the storage tank occurs from a small flow created due to the difference in density between hot and cold water. The main advantage of such systems is that they do not require a pump for circulating the water and circulation exists as long as there is sunshine. This reduces the maintenance requirements and the system is foolproof. In spite of the fact that extensive analyses of the performance of solar water heaters has been carried out by numerous researchers, almost all of them concerned forced circulation systems which use a circulating pump. Currently, the knowledge on the parameters affecting the ‘thermosiphonic phenomenon’ is rather poor while on an international level (ISO and CEN committees) there isn’t any standard to test thermosiphon solar collectors. The deeper understanding of the ‘thermosiphonic phenomenon’ and the identification of the key parameters affecting it, is the main aim of a research project currently in process in Cyprus. In this work the first preliminary results of the experimental procedure are presented. More specifically, a special test rig was set up and equipped with all sensors necessary to measure all parameters that are most likely to affect the ‘thermosiphonic phenomenon’. All tests were conducted according to ISO 9459- 2:1995(E). The system was able to operate in various weather and operating conditions and could accommodate the change of inclination of the collector. Initially, the solar collector was tested according to EN12975-2:2006 in order to determine the thermal performance at a flow and operation conditions specified by the standard. Subsequently, the efficiency of the collector operating thermosiphonically was calculated based on quasi-dynamic approach. Finally, a series of correlations were attempted using the data acquired when the collector is operating themosiphonically which are the following: (i) the temperature difference of the water at the outlet and the inlet of the collector (ΔΤ) with the solar global radiation, (ii) the water mass flow with the solar global radiation, (iii) the water mass flow with the temperature difference of the water at the outlet and the inlet of the collector (ΔΤ). The results of the data analysis showed that these parameters are very well correlated between them since the coefficient of determination (R2) is over 0.91 in all cases