Search results for " circulation"

Hydrogen and methane production in extreme thermophilic conditions in two-stage (upflow anaerobic sludge bed) UASB reactor system

2013

Abstract Two-stage hydrogen and methane production in extreme thermophilic (70 °C) conditions was demonstrated for the first time in UASB-reactor system. Inoculum used in hydrogen and methane reactors was granular sludge from mesophilic internal circulation reactor and was first acclimated for extreme thermophilic conditions. In hydrogen reactor, operated with hydraulic retention time (HRT) of 5 h and organic loading rate (OLR) of 25.1 kg COD/m 3 /d, hydrogen yield was 0.73 mol/mol glucose added . Methane was produced in second stage from hydrogen reactor effluent. In methane reactor operated with HRT of 13 h and OLR of 7.8 kg COD/m 3 /d, methane yield was 117.5 ml/g COD added . These resul…

Effect of Vegetation on Fluvial Erosion Processes: Experimental Analysis in a Laboratory Flume

2013

Abstract The plane evolution of a meander wave is determined by the erosion processes at the banks. Particularly, the outer- bank is considerably vulnerable to the erosion processes. Indirect techniques, which act upon the reduction of the effect of the cross-circulation motion, have been recently proposed to limit the outer-bank erosion. This paper shows preliminary results on the role played by vegetation on cross-circulation motion. The analysis is conducted on the basis of experimental data collected in a large amplitude meandering channel constructed at the hydraulic laboratory of DICAM. Maps describing the cross-stream flow, both over the no-vegetated bed and over the vegetated bed, a…

Quantification of deep CO2 fluxes from Central Italy. Examples of carbon balance for regional aquifers and of soil diffuse degassing.

1999

Abstract In Central Italy non-volcanic CO 2 is discharged by focused degassing (strong diffuse emission and vents) and by high-CO 2 groundwater. 3 He / 4 He data and the carbon isotopic composition of CO 2 are compatible with derivation from mantle degassing and/or metamorphic decarbonation. The gases produced at depth accumulate in permeable reservoirs composed of Mesozoic carbonates. When total pressure (roughly corresponding to p CO 2 ) of the reservoir fluid exceeds hydrostatic pressure, a free gas phase forms gas reservoirs within the permeable host rocks from which gases may escape toward the surface. This process generates both the focused vents and the CO 2 -rich springs which chara…

Changes in Latvian river discharge regime at the turn of the century

2012

The study deals with turn-of-the-century changes in the total annual river runoff distribution and high and low flows in Latvia, covering river basins within four hydrological districts which vary according to size and physiographical conditions. Mathematical statistical methods were applied in the analysis of river discharge data series for two study periods of 1951–2009 and 1881–2009. The present results confirm the basic statement concerning the Baltic countries that major significant changes in river runoff during the last two decades have occurred between spring (decrease) and winter (increase) seasons. Mostly insignificant changes in summer runoff and significant/insignificant changes…

Total (fumarolic + diffuse soil) CO2 output from Furnas volcano

2015

Furnas volcano, in São Miguel island (Azores), being the surface expression of rising hydrothermal steam, is the site of intense carbon dioxide (CO2) release by diffuse degassing and fumaroles. While the diffusive CO2 output has long (since the early 1990s) been characterized by soil CO2 surveys, no information is presently available on the fumarolic CO2 output. Here, we performed (in August 2014) a study in which soil CO2 degassing survey was combined for the first time with the measurement of the fumarolic CO2 flux. The results were achieved by using a GasFinder 2.0 tunable diode laser. Our measurements were performed in two degassing sites at Furnas volcano (Furnas Lake and Furnas Villag…

Effects of the exercise in the cerebral blood flow and metabolism: A review

2015

In recent years it has been shown that cerebral blood flow is affected by intense exercise, what may even lead to a reduction in the cognitive capacity. This statement is contrary to the traditional belief that cerebral blood flood remains constant and unaltered even when exercise is performed. During physical exercise of moderate intensity, cerebral blood flow increases in the cerebral areas responsible for movement. Moreover, recent studies have observed that cerebral blood flow decreases during high-intensity exercise as a consequence of a local hyperventilation and vasoconstriction of the areas with lower cerebral activity. Traditionally, the glucose has been considered as the main and …

L'applicazione della CITES in Europa

2008

A mixed-valence Cu(I)–Cu(II) and metal–metal bond containing coordination polymer obtained from an in situ oxidation reaction route

2006

Abstract A new mixed-valence copper coordination polymer with copper–copper metal bonds in a two-dimensional network was generated from an in situ oxidation reaction route under hydrothermal conditions. The synthesis of this coordination polymer demonstrated that the novel compounds that may not be accessible using the known methods could be synthesized via an oxidation reaction route. The reaction conditions are mild enough to keep the building blocks intact during the oxidation and self-assembly process under hydrothermal conditions.

Pathophysiology of traumatic brain injury.

2007

The knowledge of the pathophysiology after traumatic head injury is necessary for adequate and patient-oriented treatment. As the primary insult, which represents the direct mechanical damage, cannot be therapeutically influenced, target of the treatment is the limitation of the secondary damage (delayed non-mechanical damage). It is influenced by changes in cerebral blood flow (hypo- and hyperperfusion), impairment of cerebrovascular autoregulation, cerebral metabolic dysfunction and inadequate cerebral oxygenation. Furthermore, excitotoxic cell damage and inflammation may lead to apoptotic and necrotic cell death. Understanding the multidimensional cascade of secondary brain injury offers…

Chirurgie cardiaque sous circulation extra-corporelle et ses biomarqueurs : rôle du Growth / Différentiation Factor 15 (GDF 15) : études cliniques

2016

Ischemic cardiac diseases are the most frequent and deleterious pathologies leading to important cardiovascular-related mortality worldwide. One of the alternative therapies consists to treat these patients using cardiac surgery. Cardiopulmonary bypass was developed to greatly improve this surgical procedure. However, some adverse effects can occur during cardiac surgery associated with cardiopulmonary bypass due to the inflammatory response. This phenomenon is the result of various mechanisms including oxidative stress and inflammatory cytokines which lead to multi-organ failure and then to myocardial and renal injuries occurring during the peri- and post-operative periods.The first part o…