Search results for "BOG"

Electric Field Effect on the Thermal Decomposition and Co-combustion of Straw with Solid Fuel Pellets

2019

The aim of this study was to provide more effective use of straw for energy production by co-firing wheat straw pellets with solid fuels (wood, peat pellets) under additional electric control of the combustion characteristics at thermo-chemical conversion of fuel mixtures. Effects of the DC electric field on the main combustion characteristics were studied experimentally using a fixed-bed experimental setup with a heat output up to 4 kW. An axisymmetric electric field was applied to the flame base between the positively charged electrode and the grounded wall of the combustion chamber. The experimental study includes local measurements of the composition of the gasification gas, flame tempe…

The Mathematical Modeling of Ca And Fe Distribution In Peat Layers

2015

Bogs have been formed by an accumulation of peat - a light brown-to-black organic material, built up from partial decomposition of mosses and other bryophytes, sedges, grasses, shrubs, or trees under waterlogged conditions. The total peatlands area in Latvia covers 698 918 ha or 10.7% of the entire territory. Knowledge’s of peat metals content are important for any kind of peat using. Experimental determination of metals in peat is very long and expensive work. Using experimental data mathematical model for calculation of concentrations of metals in different points for different layers can help to very easy and fast to find approximately concentration of metals or trace elements. The resul…

High emissions of greenhouse gases from grasslands on peat and other organic soils

2016

Drainage has turned peatlands from a carbon sink into one of the world's largest greenhouse gas (GHG) sources from cultivated soils. We analyzed a unique data set (12 peatlands, 48 sites and 122 annual budgets) of mainly unpublished GHG emissions from grasslands on bog and fen peat as well as other soils rich in soil organic carbon (SOC) in Germany. Emissions and environmental variables were measured with identical methods. Site-averaged GHG budgets were surprisingly variable (29.2 ± 17.4 t CO2 -eq. ha-1  yr-1 ) and partially higher than all published data and the IPCC default emission factors for GHG inventories. Generally, CO2 (27.7 ± 17.3 t CO2  ha-1  yr-1 ) dominated the GHG budget. Nit…

N-quantum approach to quantum field theory at finite T and mu: the NJL model

1999

We extend the N-quantum approach to quantum field theory to finite temperature ($T$) and chemical potential ($\mu$) and apply it to the NJL model. In this approach the Heisenberg fields are expressed using the Haag expansion while temperature and chemical potential are introduced simultaneously through a generalized Bogoliubov transformation. Known mean field results are recovered using only the first term in the Haag expansion. In addition, we find that at finite T and in the broken symmetry phase of the model the mean field approximation can not diagonalize the Hamiltonian. Inclusion of scalar and axial vector diquark channels in the SU(2)$_{rm f}$ $otimes$ SU(3)$_{\rm c}$ version of the …

Invariant circles in the Bogdanov-Takens bifurcation for diffeomorphisms

1996

AbstractWe study a generic, real analytic unfolding of a planar diffeomorphism having a fixed point with unipotent linear part. In the analogue for vector fields an open parameter domain is known to exist, with a unique limit cycle. This domain is bounded by curves corresponding to a Hopf bifurcation and to a homoclinic connection. In the present case of analytic diffeomorphisms, a similar domain is shown to exist, with a normally hyperbolic invariant circle. It follows that all the ‘interesting’ dynamics, concerning the destruction of the invariant circle and the transition to trivial dynamics by the creation and death of homoclinic points, takes place in an exponentially small part of the…

Mena García, Carmen y Díaz Reina, José Antonio: El abogado que dibujó el mundo: Martín Fernández de Enciso (1469-1533), una biografía apasionante

2021

Modernisme et celticité: Les spectres excavés de Louis Le Brocquy

2013

International audience

Dynamics of tumor oxygenation and red blood cell flux in response to inspiratory hyperoxia combined with different levels of inspiratory hypercapnia.

2002

Abstract Background and purpose : Increasing arterial oxygen partial pressure (pO 2 ) by breathing hyperoxic gases is an effective means of improving tumor oxygenation, although the efficacy of adding CO 2 to the inspiratory gas has been discussed controversially. This study aimed at analyzing the impact of different inspiratory CO 2 fractions on the time course of oxygenation and perfusion changes in experimental tumors during and after inspiratory hyperoxia. Material and methods : Perfusion and oxygenation of rat DS-sarcomas were studied during spontaneous breathing of pure oxygen or hyperoxic gas mixtures containing different CO 2 fractions (1, 2.5 or 5%). Red blood cell (RBC) flux was a…

Marshall's vein persistence: A rare and occasional finding during pacemaker implantation

2012

In adults the oblique vein of Marshall is usually absent or very thin, and it is hard to be found. In this case report we describe a case of persistence observed during pacemaker implantation.

Initial experience with a new method of external polyester scaffolding for infrainguinal vein grafts.

2009

Abstract Objectives This study aims to evaluate the feasibility of external polyester scaffolding in infrainguinal bypass grafting when available vein material is suboptimal due to varicosity or dilatation. Primary objectives were short-term primary patency, assisted primary patency and secondary patency. Secondary objectives were to assess the rate of graft stenoses, infections and other adverse effects related to the use of external scaffolding. Materials and methods A total of 50 consecutive patients were included in this prospective, multicentre, feasibility study from six centres. The indication for infrainguinal bypass was critical limb ischaemia (64%), severe claudication (34%) or po…