bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of the handheld Lactate‐Pro analyzer for measurement of blood L‐lactate concentration in cattle
Authors: Buczinski Sébastien , Doré Elizabeth , Boulay Guillaume , Francoz David 
Published: August 2014

BackgroundBlood L‐lactate concentration (LAC) can be used for various diagnostic purposes in cattle. As multiple handheld analyzers for LAC exist, it is important to validate their use in cattle in comparison with reference laboratory blood analyzers.ObjectivesThe objectives of this study were to validate the handheld Lactate Pro meter (LacP) including reproducibility, and compare the measurements with the StatProfile (StatP) as a gold standard. In addition, diagnostic sensitivity and specificity, and the impact of HCT on LAC measured by both analyzers were assessed.MethodsA cohort of 64 cattle with acute medical and surgical conditions was studied. Whole blood samples in heparin lithium tubes were analyzed upon arrival with both StatP and LacP. Twenty‐three samples were immediately retested to assess intra‐assay coefficient of variation (CV). The HCT values were also recorded.ResultsThe LAC using LacP was highly correlated with the StatP (r = 0.9736 [95% confidence interval [CI]: 0.9562–0.9841]). The LacP underestimated LAC (mean difference:−0.9 mmol/L, 95% CI:−3.1 mmol/L to 1.3 mmol/L). The intra‐assay CV was excellent (4.77%). No significant correlation was observed between LacP or StatP and HCT (P = .39 and .09, respectively). Sensitivity and specificity for LacP were 91.7% (95% CI: 76.4–97.8%) and 100% (83.4–100%, cutoff of 4 mmol/L), and 78.6% (58.5–90.9%) and 100% (87.0–100%, cutoff of 6 mmol/L).ConclusionsThe LacP handheld lactate meter can be used safely and reliably cow‐side, although it underestimates LAC value when compared with a standard laboratory analyzer especially for LAC ≥ 10.0 mmol/L. The LAC value was not influenced by HCT in this study.
Combined Cycles for High Performance, Low Cost, Low Environmental Impact Waste-to-Energy Systems
Authors: Consonni Stefano 
Published: August 2014

This paper assesses the integration between natural gas-fired combined cycles and grate combustors for municipal solid waste (MSW). Saturated steam generated in the grate combustor is exported to the heat recovery steam generator (HRSG) of the combined cycle, where it is superheated and then fed to a steam turbine serving both the combined cycle and the Waste-to-Energy (WTE) plant. Using a single steam turbine reduces costs and increases efficiency; in addition, superheating steam with the clean combustion products discharged by the gas turbine avoids all penalties (and extra-costs) caused by the corrosive gases generated in the grate combustor, which follow a path and are discharged from a stack completely separated from those of the CC. The optimal CC/WTE plant match is achieved when evaporation is carried out almost exclusively in the grate combustor, with the HRSG bearing the load for superheat (and reheat) and part of feedwater heating.
Performance estimates for a combined cycle centered around a medium-size, heavy-duty gas turbine show that WTE/CC integration increases the efficiency of energy recovery from waste by 50% and more, with MSW disposal costs lower by 30–40%. Higher energy conversion efficiencies imply lower environmental impact, notably greater reductions of greenhouse gas emissions.
Application of Incomplete Measurement Data to Thermal Diagnostics of Complex Power Systems Components
Authors: Gluch Jerzy , Krzyzanowski Jerzy 
Published: August 2014

Proper exploitation of the complex power systems needs application of diagnostic tools. The diagnostics of power systems can be effective only if reliable simulation methods are available and experimental data are complete.
Unlike that last requirement, it occurs very often in practice that experimental data for particular power cycle components are incomplete. This can happen due to
- inadequate distribution of measuring devices, or
- particular design of the power cycle components which makes the measurement difficult or impossible.
The question arises if any thermal diagnostics of components measured under such condition is possible. The authors try to answer the question taking as an example a specific subsystem of complex power cycle. It is composed of two HP turbine groups of stages, control stage and some glands of the turbine. Making use of the simulation techniques, the authors investigate how much the degradation causes of the elements of this subsystem influences the degradation symptoms of the power cycle. The answer to this question can be of significant importance for the designer of the measuring system and for the user of his thermal diagnostics efforts.
Research on a Methane-Fueled Low NOx Combustor for a Mach 3 Supersonic Transporter Turbojet Engine
Authors: Kinoshita Yasuhiro , Oda Takeo , Kitajima Junichi 
Published: August 2014

Methane-fueled low NOx combustor research had been conducted under the Japanese supersonic/hypersonic propulsion research programme. A unique form of premixture jet swirl combustor (PJSC) was proposed for the ultra low NOx combustor of a Mach 3 turbojet engine. Fuel-air mixing tests and fundamental combustion tests were conducted to obtain the design data and combustion characteristics in the first phase of the research. A single can type combustor was fabricated and high temperature and high pressure combustion tests were carried out for the evaluation on NOx emission reduction capability of the PJSC concept in the second phase. In the final phase of research, a multi-sector combustor was fabricated and the performance demonstration test was conducted for the final evaluation of the pollutant exhaust emission goals and the combustor performance goals set in the HYPR project.
The sequential three phased program was completed successfully, and the project goals of NOx emission, combustion efficiency, pressure loss and exit gas temperature pattern factor at the Mach 3 cruise condition, together with the ICAO regulatory levels for supersonic aircraft at LTO conditions, were all achieved in the performance demonstration test.
Repowering of an Existing Cogeneration Plant Including Environmental Cost Internalization
Authors: Calì M. , Massardo A. F. , Santarelli M. 
Published: August 2014

In this paper an existing cogeneration plant (134 MWel and 225 MWth) based on gas turbine and steam cycle technology, has been investigated. The main goal of the work is to analyse different repowering options for the plant taking into account the capital cost of the new devices, the cost of the fuel and the cost related to the CO2 emissions. For the analysis of the repowering alternatives the Thermoeconomic Analysis has been utilised. Two different approaches have been used for the CO2 emissions cost evaluation: the classical Carbon Tax approach using political charges on the unit ton of emitted CO2, and one proposed by the Authors linked to the efficient utilization of energy resources in the plants, and based on the exergy analysis.
In the paper the two procedures for the evaluation of the charges on the CO2 emissions and their influence on the choice of the repowering option, and how they promote the adoption of a high efficiency repowering solutions have been discussed.
Natural Gas Decarbonization to Reduce CO2 Emission From Combined Cycles: Part A — Partial Oxidation
Authors: Lozza Giovanni , Chiesa Paolo 
Published: August 2014

This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to CO2 is achieved before gas turbine combustion. Therefore CO2 can be removed from fuel (rather than from exhausts, thus utilizing less demanding equipment) and made available for long-term storage, to avoid dispersion toward the atmosphere and the consequent contribution to the greenhouse effect.
The strategy here proposed to achieve this goal is natural gas partial oxidation. The second part of the paper will address steam / methane reforming. Partial oxidation is an exothermic oxygen-poor combustion devoted to CO and H2 production. The reaction products are introduced in a multiple stage shift reactor converting CO to CO2. Carbon dioxide is removed by means of physical or chemical absorption processes and made available for storage, after compression and liquefaction. The resulting fuel mainly consists of hydrogen and nitrogen, thus gas turbine exhausts are virtually devoid of CO2.
The paper discusses the selection of some important parameters necessary to obtain a sufficient level of conversion in the various reactors (temperature and pressure levels, methane-to-air or methane-to-steam ratios) and their impact on the plant integration and on the thermodynamic efficiency. Overall performance (efficiency, power output and carbon removal rate) is predicted by means of a computational tool developed by the authors. The results show that a net efficiency of 48.5%, with a 90% CO2 removal, can be obtained by combined cycles based on large heavy duty machines of the present technological status, either by using chemical or physical absorption.
Assessment of LNG Regasification Systems With Cogeneration
Authors: Desideri Umberto , Belli Claudio 
Published: August 2014

Natural gas is usually transferred to consumers through pipelines, which may cover distances of thousands of kilometers. In some cases, however, when the path of the pipelines crosses seas or countries where the politic situation does not ensure a continuous and reliable flow, other means of transportation are preferred. In these cases, the natural gas is liquefied and transported in tankers, which load the tanks at liquefaction plants and discharge them at regasification plants. This gives a considerable chance to differentiate supply sources and allows gas imports from producing countries that are otherwise inaccessible via pipeline.
The aim of this paper is the study of systems, which carry out liquefied natural gas (LNG) vaporization using cogenerative solutions. The following configurations were studied in particular:
• Gas-steam combined cycles;
• Closed gas-gas combined cycles using three different working fluids.
Two typical plant sizes and two gas pressure sendout levels (7.3 MPa for long distance pipeline networks and 2.5 MPa for terminals linked to power production plants with combined cycles) have been analyzed. The suggested solutions have been optimized, and performance calculated. The discussion is completed by a simplified economic analysis.
Flow and Heat Transfer in a Rotating Square Channel With 45° Angled Ribs by Reynolds Stress Turbulence Model
Authors: Jang Yong-Jun , Chen Hamn -Ching , Han Je-Chin 
Published: August 2014

Numerical predictions of three -dimensional flow and heat transfer are presented for a rotating square channel with 45° angled ribs as tested by Johnson et al. (1994). The rib height-to-hydraulic diameter ratio (e/Dh) is 0.1 and the rib pitch-to-height ratio (P/e) is 10. The cross-section of the ribs has rounded edges and corners. The computation results are compared with Johnson’s et al. (1994) experimental data at a Reynolds number (Re) of 25,000, inlet coolant-to-wall density ratio (Δρ/ρ) of 0.13, and three rotation numbers (Ro) of 0.0, 0.12, 0.24.
A multi-block numerical method has been employed with a near-wall second-moment turbulence closure model. In the present method, the convective transport equations for momentum, energy, and turbulence quantities are solved in curvilinear, body-fitted coordinates using the finite-analytic method. Pressure is computed using a hybrid SIMPLER/PISO approach, which satisfies the continuity of mass and momentum simultaneously at every time step. The second-moment solutions show that the secondary flows induced by the angled ribs, rotating buoyancy, and Coriolis forces produced strong non-isotropic turbulent stresses and heat fluxes that significantly affected flow fields and surface heat transfer coefficients. The present near-wall second-moment closure model provided an improved flow and heat transfer prediction.
A Transient Liquid Crystal Method Using Hue Angle and a 3-D Inverse Transient Conduction Scheme
Authors: Lin Mingjie , Wang Ting 
Published: August 2014

Various transient liquid crystal methods have been widely and routinely employed to measure surface heat transfer coefficients. Typically, the heat transfer surface was modeled as a one-dimensional, transient heat conduction over a semi-infinite surface to retrieve information of the surface heat transfer coefficients. To satisfy the theoretical initial and boundary conditions, inconvenient and/or complex designs are required. Frequently, the conditions are not exactly satisfied. To resolve these issues, an approach of measuring heat transfer coefficients coupling the transient liquid crystal method with a 3-D inverse transient conduction scheme was developed and was applied to a nonuniform heat transfer surface produced by arrays of impinging jets.
The present method utilized the hue-angle method to process the color images captured from the liquid crystal color play. Instantaneous temperature readings from embedded thermocouples were utilized for in-situ calibration of hue angle for each data set. The convective heat transfer coefficient results were obtained by performing a 3-D inverse transient conduction calculation over the entire jet impingement target surface and the substrate. The results of average heat transfer coefficients agreed well with previous experimental results of point measurements by thermocouples.
High Lift and Aft Loaded Profiles for Low Pressure Turbines
Authors: Howell R. J. , Ramesh O. N. , Hodson H. P. , Harvey N. W. , Schulte V. 
Published: August 2014

This paper shows how it is possible to reduce the number of blades in LP turbines by approximately 15% relative to the first generation of high lift blading employed in the very latest engines. This is achieved through an understanding of the behaviour of the boundary layers on high lift and ultra high lift profiles subjected to incoming wakes.
Initial development of the new profiles was carried out by attaching a flap to the trailing edge of one blade in a linear cascade. The test facility allows for the simulation of upstream wakes by using a moving bar system. Hot wire measurements were made to obtain boundary layer losses and surface mounted hot films were used to observe the changes in boundary layer state. Measurements were taken at a Reynolds number between 100,000 and 210,000.
The effect of increased lift above the datum profile was investigated first with steady and then with unsteady inflow (i.e. with wakes present). For the same profile, the losses generated with wakes present were below those generated by the profile with no wakes present. The boundary layer behaviour on these very high lift pressure distributions suggested that aft loading the profiles would further reduce the profile loss.
Finally, two very highly loaded and aft loaded LP turbine profile were designed and then tested in cascade. The new profiles produced losses only slightly higher than those for the datum profile with unsteady inflow, but generated 15% greater lift.
Bypass Transition Modelling: A New Method Which Accounts for Free-Stream Turbulence Intensity and Length Scale
Authors: Roach Paul E. , Brierley David H. 
Published: August 2014

The publication of the present authors’ boundary layer transition data in 1992 (now widely known as the ERCOFTAC test case T3) has led to a spate of new experimental and modelling efforts aimed at improving our understanding of this problem. This paper describes a new method of determining boundary layer transition with zero mean pressure gradient. The approach examines the development of a laminar boundary layer to the start of transition, accounting for the influences of free-stream turbulence and test surface geometry. It is presented as a “proof of concept”, requiring a significant amount of work before it can be considered as a practically applicable model for transition prediction. The method is based upon one first put forward by G.I. Taylor in the 1930’s, and accounts for the action of local, instantaneous pressure gradients on the developing laminar boundary layer. These pressure gradients are related to the intensity and length scale of turbulence in the free-stream using Taylor’s simple isotropic model.
The findings demonstrate the need to account for the separate influences of free-stream turbulence intensity and length scale when considering the transition process. Although the length scale has less of an effect than the intensity, its influence is, nevertheless, significant and must not be overlooked. This fact goes a long way towards explaining the large scatter to be found in simple correlations which involve only the turbulence intensity. Intriguingly, it is demonstrated that it is the free-stream turbulence at the leading edge of the test surface which is important, not that found locally outside the boundary layer.
The additional influence of leading edge geometry is also shown to play a major role in fixing the point at which transition begins. It is suggested that the leading edge geometry will distort the incident turbulent eddies, modifying the effective “free-stream” turbulence properties. Consequently, it is shown that the scale of the eddies relative to the leading edge thickness is a further important parameter, and helps bring together a large number of test cases.
Total Pressure Losses in Rotor Systems With Radial Inflow
Authors: Brillert D. , Lieser D. , Reichert A. W. , Simon H. 
Published: August 2014

Gas turbines with a splined-disc rotor design allow the compressor bleed pressure to be adapted precisely to the requirements of rotor cooling air systems in which the cooling air is routed through the spaced between the rotating discs.
Calculation of such flows is extremely difficult; particularly so if the flow is directed radially inward. In such cases the circumferential component of the absolute velocity can be very high and can thus lead to pronounced total pressure losses.
The paper gives a brief description of the flow phenomena, and details in the calculation methods cited in the literature.
Navier–Stokes calculations were carried out for the flow through a model test bed engine. The results are compared with experimental data.
A simple calculation model is discussed and its result compared with test data.
The model predicts the flow pattern more accurately than the Navier-Stokes calculations, and this paper shows that the simple model can be improved further.
Large-Scale Testing to Validate the Influence of External Crossflow on the Discharge Coefficients of Film Cooling Holes
Authors: Rowbury D. A. , Oldfield M. L. G. , Lock G. D. 
Published: August 2014

This paper discusses large-scale, low-speed experiments that explain unexpected flow-interaction phenomena witnessed during annular cascade studies into the influence of external crossflow on film cooling hole discharge coefficients. More specifically, the experiments throw light on the crossover phenomenon, where the presence of the external crossflow can, under certain circumstances, increase the discharge coefficient. This is contrary to most situations, where the external flow results in a decrease in discharge coefficient. The large-scale testing reported helps to explain this phenomena through an increased understanding of the interaction between the emerging coolant jet and the freestream flow.
The crossover phenomenon came to light during an investigation into the influence of external crossflow on the discharge coefficients of nozzle guide vane film cooling holes. These experiments were performed in the Cold Heat Transfer Tunnel (CHTT), an annular blowdown cascade of film cooled vanes which models the three-dimensional external flow patterns found in modern aero-engines. (Rowbury et al., 1997 and 1998).
The variation in static pressure around the exit of film cooling holes under different flow conditions was investigated in the large-scale tests. The study centred on three holes whose geometries were based on those found in the leading edge region of the CHTT vanes, as the crossover phenomenon was witnessed for these rows during the initial testing. The experiments were carried out in a low speed wind tunnel, with the tunnel freestream flow velocity set to match the freestream Reynolds number (as based on the local radius of curvature) and the ‘coolant’ flow velocity set to replicate the engine coolant-to-freestream momentum flux ratio.
It was found that the apparent enhancement of film cooling hole discharge coefficients with external crossflow was caused by a reduction in the static pressure around the hole exit, associated with the local acceleration of the freestream around the emerging coolant jet. When these measured static pressures (rather than the freestream static pressure) were used to calculate the discharge coefficient, the crossover effect was absent. The improved understanding of the crossover phenomenon and coolant-to-freestream interactions that has been gained will be valuable in aiding the formulation of predictive discharge coefficient schemes.
Effect of Crystal Orientation on Fatigue Failure of Single Crystal Nickel Base Turbine Blade Superalloys
Authors: Arakere Nagaraj K. , Swanson Gregory 
Published: August 2014

High Cycle Fatigue (HCF) induced failures in aircraft gas turbine and rocket engine turbopump blades is a pervasive problem. Single crystal nickel turbine blades are being utilized in rocket engine turbopumps and jet engines throughout industry because of their superior creep, stress rupture, melt resistance and thermomechanical fatigue capabilities over polycrystalline alloys. Currently the most widely used single crystal turbine blade superalloys are PWA 1480/1493, PWA 1484, RENE’ N-5 and CMSX-4. These alloys play an important role in commercial, military and space propulsion systems. Single crystal materials have highly orthotropic properties making the position of the crystal lattice relative to the part geometry a significant factor in the overall analysis. The failure modes of single crystal turbine blades are complicated to predict due to the material orthotropy and variations in crystal orientations. Fatigue life estimation of single crystal turbine blades represents an important aspect of durability assessment. It is therefore of practical interest to develop effective fatigue failure criteria for single crystal nickel alloys and to investigate the effects of variation of primary and secondary crystal orientation on fatigue life.
A fatigue failure criterion based on the maximum shear stress amplitude [Δτmax] on the 24 octahedral and 6 cube slip systems, is presented for single crystal nickel superalloys (FCC crystal). This criterion reduces the scatter in uniaxial LCF test data considerably for PWA 1493 at 1200F in air. Additionally, single crystal turbine blades used in the alternate advanced high-pressure fuel turbopump (AHPFTP/AT) are modeled using a large-scale 3D finite element (FE) model. This FE model is capable of accounting for material orthotrophy and variation in primary and secondary crystal orientation. Effects of variation in crystal orientation on blade stress response are studied based on 297 FE model runs. Fatigue lives at critical points in the blade are computed using FE stress results and the failure criterion developed. Stress analysis results in the blade attachment region are also presented. Results presented demonstrates that control of secondary and primary crystallographic orientation has the potential to significantly increase a component’s resistance to fatigue crack growth without adding additional weight or cost.