bluuebunny/crossref_metadata_2025_split huggingface dataset:
Slowed oxygen uptake kinetics in hypoxia correlate with the transient peak and reduced spatial distribution of absolute skeletal muscle deoxygenation
Authors: Bowen T. Scott , Rossiter Harry B. , Benson Alan P. , Amano Tatsuro , Kondo Narihiko , Kowalchuk John M. , Koga Shunsaku 
Published: July 2013

New findings
What is the central question of the study?Does a transient overshoot in skeletal muscle deoxygenation (reflecting a kinetic mismatch of microvascular O2 delivery to consumption) and/or its spatial distribution slow the adjustment of oxidative energy provision at the onset of exercise?
What is the main finding and its importance?Slowed oxidative energy provision at the onset of exercise was correlated with the transient skeletal muscle deoxygenation peak and the reduced spatial distribution, measured by quantitative near‐infrared spectroscopy. It was not correlated with a microvascular O2 delivery‐to‐consumption mismatch per se. This suggests that an absolute, rather than kinetic, mismatch of microvascular O2 delivery and consumption limits the kinetics of muscular oxidative energy provision, but only when muscle deoxygenation reaches some ‘critical’ level.
It remains unclear whether an overshoot in skeletal muscle deoxygenation (HHb; reflecting a microvascular kinetic mismatch of O2 delivery to consumption) contributes to the slowed adjustment of oxidative energy provision at the onset of exercise. We progressively reduced the fractional inspired O2 concentration () to investigate the relationship between slowed pulmonary O2 uptake () kinetics and the dynamics and spatial distribution of absolute [HHb]. Seven healthy men performed 8 min cycling transitions during normoxia (), moderate hypoxia () and severe hypoxia (). uptake was measured using a flowmeter and gas analyser system. Absolute [HHb] was quantified by multichannel, time‐resolved near‐infrared spectroscopy from the rectus femoris and vastus lateralis (proximal and distal regions), and corrected for adipose tissue thickness. The phase II time constant was slowed (P < 0.05) as decreased (normoxia, 17 ± 3 s; moderate hypoxia, 22 ± 4 s; and severe hypoxia, 29 ± 9 s). The [HHb] overshoot was unaffected by hypoxia, but the transient peak [HHb] increased with the reduction in (P < 0.05). Slowed kinetics in hypoxia were positively correlated with increased peak [HHb] in the transient (r2= 0.45; P < 0.05), but poorly related to the [HHb] overshoot. A reduction of spatial heterogeneity in peak [HHb] was inversely correlated with slowed kinetics (r2= 0.49; P < 0.05). These data suggest that aerobic energy provision at the onset of exercise may be limited by the following factors: (i) the absolute ratio (i.e. peak [HHb]) rather than the kinetic ratio (i.e. [HHb] overshoot) of microvascular O2 delivery to consumption; and (ii) a reduced spatial distribution in the ratio of microvascular O2 delivery to consumption across the muscle.
Ejector Scavenging of Bearing Chambers: A Numerical and Experimental Investigation
Authors: Flouros Michael , Cottier Francois , Hirschmann Markus , Kutz Joachim , Jocher Agnes 
Published: July 2013

Oil system architecture in aero engines has remained almost the same for the last 30 years. At least one oil feed pump is responsible for distributing pressurized oil into the bearing chambers and several scavenge pumps are responsible for evacuating the bearing chambers from the oil and the air mixture. Air is used as the sealing medium in bearing chambers and is the dominant medium in terms of volume occupation and expansion phenomena.
In order to simplify the oil system architecture and thus improve the system’s reliability with less mechanical parts and also decrease weight an ejector system has been designed for scavenging bearing chambers. The idea behind the ejector is to use high pressure oil from the feed pump and use it for feeding the ejector’s primary jet. Through the momentum transfer between the pressurized oil at the jet’s tip and the two phase mixture of air and oil from the bearing chamber the mixture will be discharged into the oil tank. In order to design the ejector for aero engine applications, engine relevant performance conditions had to be considered. The design was performed using a one dimensional analysis tool and then considerably refined by using the numerical tool ANSYS CFX. In a further step the ejector was manufactured out of pure quartz glass and was tested in a lube rig with a bearing chamber which has evolved from a real engine application. In the bearing chamber engine relevant performance conditions were simulated. Through the provided instrumentation for pressures, temperatures and air/oil flows the performance characteristics of the ejector were assessed and were compared to the analytic and numerical results. A high speed camera was used to record the two phase flow downstream of the bearing chamber in the scavenge pipe.
This work is part of the European Union funded research programme ELUBSYS (Engine LUBrication System TechnologieS) within the 7th EU Frame Programme for Aeronautics and Transport (AAT.2008.4.2.3).
Fuelling Micro Gas Turbines With Vegetable Oils: Part II — Experimental Analysis
Authors: Cavarzere A. , Morini M. , Pinelli M. , Spina P. R. , Vaccari A. , Venturini M. 
Published: July 2013

The application of bio-fuels in automotive, power generation and heating applications is constantly increasing. However, the use of straight vegetable oil (pure or blended with diesel) to feed a gas turbine for electric power generation still requires experimental effort, due to the very high viscosity of straight vegetable oils.
In this paper, the behavior of a Solar T-62T-32 micro gas turbine fed by vegetable oils is investigated experimentally. The vegetable oils are supplied to the micro gas turbine as blends of diesel and straight vegetable oils in different concentrations, up to pure vegetable oil.
This paper describes the test rig used for the experimental activity and reports some experimental results, which highlight the effects of the different fuels on micro gas turbine performance and pollutant emissions. Moreover, an identification model is set up to predict the behavior of the considered gas turbine, when fuelled by vegetable oil, and the sensitivity of micro gas turbine thermodynamic measurements and emissions is quantitatively established.
Study on the Flow Characteristics of High-Pressure and Dense-Phase Pneumatic Conveying of Different Pulverized Coal in IGCC Field
Authors: Lu Peng , Han Dong , Pu Wenhao , Yue Chen 
Published: July 2013

Entrained flow coal gasification is the key technology in IGCC field for its cleanness and high-efficiency. High-pressure and dense-phase pneumatic conveying of pulverized coal is of great importance for the entrained flow pulverized coal gasification. There are great differences between dense-phase pneumatic conveying systems at high pressure and common pneumatic conveying systems because of its lower conveying speed, high solid concentration and complex flow patterns.
By changing conveying pressure, total differential pressure and fluidizing gas flow rate, experimental investigations were conducted on the conveying characteristics of pulverized coal with different coal category, different particle size, and different moisture content. The results showed that pneumatic conveying at high pressure is more propitious to obtain higher solid flux, higher solid-gas ratio and lower velocity transport. Solid flux increased with the total differential pressure but the trend was lowered at last due to the system limit. Solid-gas ratio increased at first and then decreased with the total differential pressure. Both solid flux and solid-gas ratio increased slightly with fluidizing gas flow rate at first and then decreased a little for the pulverized coal of two different particle sizes. Pulverized coal with the smaller particle size possessed better conveying ability and was easier to obtain higher solid-gas ratio. Solid flux of Inner Mongolia lignite decreased with the increasing moisture content in the pulverized coal. Conveying ability of Yanzhou bituminous coal was the best and Inner Mongolia bituminous coal was the worst among the three representative coal kinds in China tested. The characteristics of the pressure drops at different pipeline test sections were investigated considering the total differential pressure, solid-gas ratio, particle sizes and moisture content, respectively. Supplemental gas flow rate should be restricted to a range in order to transport successfully when conveying Inner Mongolia bituminous coal of 300μm. The work above will provide valuable experiences for future research on high-pressure and dense-phase pneumatic conveying of pulverized coal in IGCC field.
Influence of Coal Rank on the Process of Plasma Aided Gasification
Authors: Messerle V. E. , Ustimenko A. B. , Slavinskaya N. A. , Riedel U. 
Published: July 2013

This paper describes numerical and experimental investigations of coal gasification in a combined arc-plasma entrained flow gasifier. The experimental installation is intended to operate in the electric power range of 30–100 kW, mass averaged temperature 1800–4000 K, coal dust consumption 3–10 kg·h−1 and gas-oxidant flow 0.5–15 kg·h−1.
The numerical experiments were conducted using the PLASMA-COAL computer code. It was designed for computation of the processes in plasma gasifiers. This code is based on a one-dimensional model, which describes the two-phase chemically reacting flow with an internal plasma source. The thermo-chemical conversion of the oxidizer-coal mixture is described through formation of primary volatile products, their conversion in the gas phase and the coke residue gasification reactions.
Kazakhstan Ekibastuz bituminous coal of 40% ash content, Germany Saarland bituminous coal of 10.5% ash content and 14% ash content bituminous coal from the Middleburg opencast mines, South Africa, were used for the investigation.
Performed investigations demonstrate that regardless of the coal quality the plasma assisted coal gasification allows obtaining a pure synthesis gas at a ratio of H2:CO≥1.
Energy and Cost Analysis of Small Size CHP Coal Gasification Plants Integrated With Syngas Storage Systems
Authors: Cau Giorgio , Cocco Daniele , Serra Fabio 
Published: July 2013

This study evaluates the load modulation capabilities of small and medium size CHP systems based on integrated coal gasification and syngas storage (ICGSS) power plants. ICGSS systems can perform a load-following service since a portion of the produced syngas is stored during periods of low energy demand and used to increase power output during periods of peaking demand. In particular, the main energy and economic performance of ICGSS power generation plants were evaluated with reference to three different prime movers (gas turbines, internal combustion engines and hybrid fuel cell systems) and as a function of the required electrical load curve. Moreover, a preliminary economic analysis was also carried out to evaluate the energy production cost in comparison with base-load energy production cost.
The results of the study show that ICGSS power plants offer considerable scope for enhancing operating flexibility and load modulation capabilities of CHP systems based on coal gasification. In comparison to coal gasification power plants designed to produce only base-load energy, ICGSS systems require a more powerful prime mover and a larger coal gasification section. In the field of duty-cycles of more likely interest, the coal gasification section needs to be enlarged by 5–50% and a fraction from 2% to 16% of the produced syngas needs to be stored. ICGSS plants based on hybrid fuel cells performed better in terms of electrical efficiency. Moreover, with respect to the corresponding base-load systems, electrical efficiency decreases by about 2–3 percentage points for ICGSS-GT and ICGSS-ICE, while it increases by about 1–2 percentage points for ICGSS-HFC. Finally, syngas storage can reduce energy costs in CHP systems, especially in the case high peaking electricity requirements, large useful heat productions and by using ICGSS based on ICE as prime movers.
Aeroacoustic Computations of Contra-Rotating Open Rotors Using the Nonlinear Harmonic Method and a Chorochronic Approach
Authors: Hoffer P.-A. , Deconinck T. , Hirsch Ch. , Ortun B. , Canard-Caruana S. , Rahier G. , Pascal S. , Caruelle B. 
Published: July 2013

Due to their great potential for fuel saving, Contra-Rotating Open Rotors (CRORs) receive renewed interest by the airframers and the engine manufacturers. The inherent high efficiency of this propulsion system, however, is potentially offset by the level of noise emitted by the open blades. The acoustic impact on passengers and community may represent a major issue to their environmental acceptance. Fast and robust noise prediction tools are clearly required to support the development of quieter propellers and their integration in future civil aeronautical transport. The most common strategy for noise estimation consists in a two-step approach, based on the Lighthill analogy: unsteady near-field aerodynamic flow simulation to evaluate the noise sources, coupled to a far-field acoustic propagation code.
Focus is given here on two structured grid flow solvers employed to investigate a scale-model of a 12×10 pusher CROR. The unsteady aerodynamic three-dimensional flow is indeed computed for typical cruise conditions using both the nonlinear harmonic method (NLH) of FINE™/Turbo software and elsA’s chorochronic technique. The evaluation of the far-field noise based on the aerodynamic fields is then carried out with the KIM code, Onera’s acoustic propagation code based on the Ffowcs-Williams and Hawkings (FW-H) formulation.
The obtained results enable an analysis of the complex aerodynamic interactions between the two propellers that generate interaction tones in the acoustic signature of the propulsion system. A comparison in terms of numerical settings, computational costs and flow fields is performed between the two CFD methods, which show an excellent match of the predicted global performance of the propulsion system. Some differences in the predicted acoustic signatures are discussed in the paper.
Airframe Installation Effects on the Jet Exhausting a Coaxial Nozzle System of a Gas Turbine Engine
Authors: Mihaescu Mihai , Semlitsch Bernhard , Fuchs Laszlo , Gutmark Ephraim J. 
Published: July 2013

Jet engine installation effects can significantly affect the behavior of the exhausting flow otherwise axisymmetric for an axial-symmetric nozzle configuration. Considering the problem associated solely with the turbulent jet (i.e. neglecting jet interaction with the airframe or the flight effects) has severe limitations on accurately predicting the real case scenario. It should also be emphasized that the major sources of noise for an aircraft are the high velocity, turbulent hot jets exhausting aircraft’s gas turbine engines. Therefore, the prediction of the compressible jet by including wing and pylon effects represents today a topic of high interest in aeroacoustics.
A numerical study is carried out for analyzing the flow associated with a separate flow nozzle system with and without installation effects. The Baseline case (without airframe installation) is compared with the case in which only the pylon is considered and with the case where the wing and the pylon are interfering with the jet engine. The simulations are performed with and without forward-flight effects. The tertiary flow increases the length of the potential core region while limiting the radial spread of the jet. The airframe installation effects increase the jet spreading underneath the pylon-nozzle-wing assembly while lowering the production of turbulence in that region. Particle Imaging Velocimetry experimental flow data are used to validate the computational results for the Baseline and the Pylon cases without the forward-flight effects.
A Fluid Structure Interaction Simulation of the Cerebrospinal Fluid, Spinal Cord, and Spinal Stenosis Present in Syringomyelia
Authors: Liu Yifei , Martin Bryn A. , Royston Thomas J. , Loth Francis 
Published: July 2013

Syringomyelia (SM) is a neurological disease in which a fluid-filled cystic cavity, or syrinx, forms in the spinal cord (SC) resulting in progressive loss of sensory, motor functions, and/or pain in the patient. It has been hypothesized that abnormal cerebrospinal fluid (CSF) pressure distribution and absorption in the subarachnoid space (SAS), resulting from a CSF flow blockage (stenosis), could be a key etiological factor for syrinx pathogenesis. In particular, the magnitude of the abrupt SAS pressure waves produced during coughing has been correlated with headache and pain in the patient.
To better understand the influence of coughing on the spinal SAS, four axisymmetric fluid-structure interaction (FSI) in silico models representative of various conditions associated with SM were constructed. Each of the models was subjected to a cough-like CSF pressure pulse.
The CSF flow stenosis was shown to attenuate and decelerate the CSF wave propagation in the SAS. The spinal SAS distensibility was also shown to have significant influence on the wave propagation. The in silico pressure results were found to be in agreement with a set of similar in vitro experiments [1].
An Improved Dummy Neck Assembly for Dynamic Rollover Testing
Authors: Paver Jacqueline G. , Caplinger Justin , Mattos Garrett , Friedman Donald 
Published: July 2013

In the U.S., more than 27,000 catastrophic and fatal injuries occur annually in rollover crashes. Due to the incidence and severity of injuries in rollover crashes, a strategy for injury mitigation is dynamic compliance testing with dummy-occupied vehicles and occupant protection requirements, similar to that required for frontal and side impacts. Presently, there are dynamic vehicle rollover test devices like the Controlled Rollover Impact System and the Jordan Rollover System that realistically recreate real-world rollover crash scenarios. However, the Hybrid III dummy, which is considered to be the best available human surrogate for dynamic rollover tests, has a very stiff neck with limited biofidelity in rollover crashes; the Hybrid III neck is much stiffer than the human neck. Catastrophic human head or neck injuries resulting from roof interaction and partial ejection in real-world rollover crashes are poorly replicated by dynamic rollover tests with the non-biofidelic Hybrid III dummy neck. Only with a more biofidelic dummy can effective testing result in injury mitigation in rollover crashes.
This study is part of an ongoing research project aimed at mitigating catastrophic human neck injuries in real-world rollover crashes. The goal was to develop a biofidelic neck assembly for the Hybrid III dummy in rollover crash environments. The design goals of this prototype neck included decreased stiffness and a mechanism that represents the unknowable human muscle tension in rollover crash environments.
This paper and its companion paper in this conference introduce the new neck design, present results of matched-pair tests that compare the responses of the new neck with the production Hybrid III neck, and propose preliminary rollover injury criteria for this neck. The neck demonstrates repeatability, improved biofidelity, which results in more realistic occupant kinematics, dynamics, injury prediction, and evaluation of various countermeasures.
Biofilm Formation by the Fish Pathogen Flavobacterium columnare: Development and Parameters Affecting Surface Attachment
Authors: Cai Wenlong , De La Fuente Leonardo , Arias Covadonga R. 
Published: July 2013

ABSTRACT

Flavobacterium columnare
is a bacterial fish pathogen that affects many freshwater species worldwide. The natural reservoir of this pathogen is unknown, but its resilience in closed aquaculture systems posits biofilm as the source of contagion for farmed fish. The objectives of this study were (i) to characterize the dynamics of biofilm formation and morphology under static and flow conditions and (ii) to evaluate the effects of temperature, pH, salinity, hardness, and carbohydrates on biofilm formation. Nineteen
F. columnare
strains, including representatives of all of the defined genetic groups (genomovars), were compared in this study. The structure of biofilm was characterized by light microscopy, confocal laser scanning microscopy, and scanning electron microscopy.
F. columnare
was able to attach to and colonize inert surfaces by producing biofilm. Surface colonization started within 6 h postinoculation, and microcolonies were observed within 24 h. Extracellular polysaccharide substances and water channels were observed in mature biofilms (24 to 48 h). A similar time course was observed when
F. columnare
formed biofilm in microfluidic chambers under flow conditions. The virulence potential of biofilm was confirmed by cutaneous inoculation of channel catfish fingerlings with mature biofilm. Several physicochemical parameters modulate attachment to surfaces, with the largest influence being exerted by hardness, salinity, and the presence of mannose. Maintenance of hardness and salinity values within certain ranges could prevent biofilm formation by
F. columnare
in aquaculture systems.
A Novel Bacillus thuringiensis Cry-Like Protein from a Rare Filamentous Strain Promotes Crystal Localization within the Exosporium
Authors: Ammons David R. , Reyna Antonio , Granados Jose C. , Ventura-Suárez Antonio , Rojas-Avelizapa Luz I. , Short John D. , Rampersad Joanne N. 
Published: July 2013

ABSTRACT

Mutation of a novel
cry
-like gene (
cry256
) from
Bacillus thuringiensis
resulted in a protein crystal, normally located within the spore's exosporium, being found predominately outside the exosporium. The
cry256
gene codes for a 3-domain Cry-like protein that does not correspond to any of the known Cry protein holotypes.
Live-Cell Imaging Tool Optimization To Study Gene Expression Levels and Dynamics in Single Cells of Bacillus cereus
Authors: Eijlander Robyn T. , Kuipers Oscar P. 
Published: July 2013

ABSTRACT

Single-cell methods are a powerful application in microbial research to study the molecular mechanism underlying phenotypic heterogeneity and cell-to-cell variability. Here, we describe the optimization and application of single-cell time-lapse fluorescence microscopy for the food spoilage bacterium
Bacillus cereus
specifically. This technique is useful to study cellular development and adaptation, gene expression, protein localization, protein mobility, and cell-to-cell communication over time at the single-cell level. By adjusting existing protocols, we have enabled the visualization of growth and development of single
B. cereus
cells within a microcolony over time. Additionally, several different fluorescent reporter proteins were tested in order to select the most suitable green fluorescent protein (GFP) and red fluorescent protein (RFP) candidates for visualization of growth stage- and cell compartment-specific gene expression in
B. cereus
. With a case study concerning
cotD
expression during sporulation, we demonstrate the applicability of time-lapse fluorescence microscopy. It enables the assessment of gene expression levels, dynamics, and heterogeneity at the single-cell level. We show that
cotD
is not heterogeneously expressed among cells of a subpopulation. Furthermore, we discourage using plasmid-based reporter fusions for such studies, due to an introduced heterogeneity through copy number differences. This stresses the importance of using single-copy integrated reporter fusions for single-cell studies.