bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intravenous curcumin efficacy on healing and scar formation in rabbit ear wounds under nonischemic, ischemic, and ischemia–reperfusion conditions
Authors: Jia Shengxian , Xie Ping , Hong Seok Jong , Galiano Robert , Singer Adam , Clark Richard A. F. , Mustoe Thomas A. 
Published: September 2014

AbstractCurcumin, a spice found in turmeric, is widely used in alternative medicine for its purported anti‐inflammatory and antioxidant activities. The goal of this study was to test the curcumin efficacy on rabbit ear wounds under nonischemic, ischemic, and ischemia–reperfusion conditions. Previously described models were utilized in 58 New Zealand White rabbits. Immediately before wounding, rabbits were given intravenous crude or pure curcumin (6 μg/kg, 30 μg/kg, or 60 μg/kg) dissolved in 1% ethanol. Specimens were collected at 7–8 days to evaluate the effects on wound healing and at 28 days to evaluate the effects on hypertrophic scarring. Student's t test was applied to screen difference between any treatment and control group, whereas analysis of variance was applied to further analyze for all treatment groups in aggregate in some specific experiments. Treatment with crude curcumin suggested accelerated wound healing that reached significance for reepithelialization in lower and medium doses and granulation tissue formation in lower dose. Purified curcumin became available and was used for all later experiments. Treatment with pure curcumin suggested accelerated wound healing that reached significance for reepithelialization in lower and medium doses and granulation tissue formation in lower dose. Treatment with pure curcumin significantly promoted nonischemic wound healing in a dose–response fashion compared with controls as judged by increased reepithelialization and granulation tissue formation. Improved wound healing was associated with significant decreases in pro‐inflammatory cytokines interleukin (IL)‐1 and IL‐6 as well as the chemokine IL‐8. Curcumin also significantly reduced hypertrophic scarring. The effects of curcumin were examined under conditions of impaired healing including ischemic and ischemia–reperfusion wound healing, and beneficial effects were also seen, although the dose response was less clear. Systemically administrated pure curcumin significantly promotes nonischemic wound healing and reduces hypertrophic scarring. Improvements in wound healing were associated with decreased inflammatory markers in wounds. Further study is needed to optimize dosing in ischemic and ischemia–reperfusion wound healing. In aggregate, the studies strongly support the systemic administration of curcumin to improve wound healing.
Impact of a novel, antimicrobial dressing on in vivo, Pseudomonas aeruginosa wound biofilm: Quantitative comparative analysis using a rabbit ear model
Authors: Seth Akhil K. , Zhong Aimei , Nguyen Khang T. , Hong Seok J. , Leung Kai P. , Galiano Robert D. , Mustoe Thomas A. 
Published: September 2014

AbstractThe importance of bacterial biofilms to chronic wound pathogenesis is well established. Different treatment modalities, including topical dressings, have yet to show consistent efficacy against wound biofilm. This study evaluates the impact of a novel, antimicrobial Test Dressing on Pseudomonas aeruginosa biofilm‐infected wounds. Six‐mm dermal punch wounds in rabbit ears were inoculated with 106 colony‐forming units of P. aeruginosa. Biofilm was established in vivo using our published model. Dressing changes were performed every other day with either Active Control or Test Dressings. Treated and untreated wounds were harvested for several quantitative endpoints. Confirmatory studies were performed to measure treatment impact on in vitro P. aeruginosa and in vivo polybacterial wounds containing P. aeruginosa and Staphylococcus aureus. The Test Dressing consistently decreased P. aeruginosa bacterial counts, and improved wound healing relative to Inactive Vehicle and Active Control wounds (p < 0.05). In vitro bacterial counts were also significantly reduced following Test Dressing therapy (p < 0.05). Similarly, improvements in bacterial burden and wound healing were also achieved in polybacterial wounds (p < 0.05). This study represents the first quantifiable and consistent in vivo evidence of a topical antimicrobial dressing's impact against established wound biofilm. The development of clinically applicable therapies against biofilm such as this is critical to improving chronic wound care.
Fuel Influence on Targeted Gas Turbine Combustion Properties: Part I — Detailed Diagnostics
Authors: Mosbach Thomas , Burger Victor , Gunasekaran Barani 
Published: September 2014

The threshold combustion performance of different fuel formulations under simulated altitude relight conditions were investigated in the altitude relight test facility located at the Rolls-Royce plc. Strategic Research Centre in Derby, UK. The combustor employed was a twin-sector representation of an RQL gas turbine combustor. Eight fuels including conventional crude-derived Jet A-1 kerosene, synthetic paraffinic kerosenes (SPKs), linear paraffinic solvents, aromatic solvents and pure compounds were tested. The combustor was operated at sub-atmospheric air pressure of 41 kPa and air temperature of 265 K. The temperature of all fuels was regulated to 288 K. The combustor operating conditions corresponded to a low stratospheric flight altitude near 9 kilometres.
The experimental work at the Rolls-Royce (RR) test-rig consisted of classical relight envelope ignition and extinction tests, and ancillary optical measurements: Simultaneous high-speed imaging of the OH* chemiluminescence and of the soot luminosity was used to visualize both the transient combustion phenomena and the combustion behaviour of the steady burning flames. Flame luminosity spectra were also simultaneously recorded with a spectrometer to obtain information about the different combustion intermediates and about the thermal soot radiation curve. This paper presents first results from the analysis of the weak extinction measurements. Further detailed test fuel results are the subject of a separate complementary paper [1].
It was found in general that the determined weak extinction parameters were not strongly dependent on the fuels investigated, however at the leading edge of the OH* chemiluminescence intensity development in the pre-flame region fuel-related differences were observed.
Online Performance Monitoring of Industrial Compressors Using Meanline Modelling
Authors: Cicciotti Matteo , Xenos Dionysios P. , Bouaswaig Ala E. F. , Thornhill Nina F. , Martinez-Botas Ricardo F. 
Published: September 2014

This paper proposes a framework for detecting mechanical degradation online and assessing its effect on the performance of industrial compressors. It consists of a model of the machine in undegraded condition and of a degradation adaptive model. The proposed methodology for online degradation detection differentiates itself from those found in the literature as the undegraded model is not linearized and ambient/inlet conditions are explicitly taken into account. The degradation is modelled through adaptive parameters which are estimated and updated online through the solution of a constrained minimization problem within a moving window. It uses available process measurements of flow, pressures, temperatures and composition. The update of the parameters guarantees the model accuracy and it permits the estimation of the effects of mechanical degradation away from the compressor running line.
The performance monitoring framework has been successfully applied on an industrial air centrifugal compressor. It was found that after 3250 hours of operation from the previous maintenance the efficiency and the pressure ratio had dropped approximately 5.5% and 2.5% of their respective undegraded values. Furthermore, it was found that the performance deviations from the baseline depend from the position of the operative point in the performance map. In fact, the pressure ratio drop was lower (2%) and efficiency drop was higher (6%) for lower inlet guide vanes opening whereas pressure ratio drop was higher (3%) and efficiency drop was lower (1.6%) for higher inlet guide vane opening.
Aerodynamics Study of a Linearly-Arranged 5-Swirler Array
Authors: Kao Yi-Huan , Tambe Samir B. , Jeng San-Mou 
Published: September 2014

In this experimental work, a series of tests have been conducted to further study the aerodynamics of linearly-arranged 5-swirler arrays, using Laser Doppler Velocimetry (LDV). Two major parameters have been investigated for the 5-swirler arrays in this work, including the inter-swirler spacing, and the end wall distance. An additional effect of dome recession was studied for a single swirler in order to provide some insight into the results for the 5-swirler arrays.
The 5-swirler arrays with an inter-swirler spacing of 1.75D, 2D, 2.5D, and 2.75D were studied, where D is the diameter of swirler exit. For the inter-swirler spacing of 1.75D or 2D, the center swirler is shown to have a weak, large center toroidal recirculation zone (CTRZ). The swirlers next to the center swirlers have strong, compact CTRZs whereas the outer swirlers have weak, large CTRZs. Thus, starting from the center swirler, the CTRZs exhibit a large – small – large pattern in either direction. For the swirler spacing of 2.5D or 2.75D, the trend is reversed, with a strong CTRZ for the center swirler and a small – large – small CTRZ pattern.
The end wall distances of 0.75D, 1D, 1.25D, and 2D cases were studied. The end wall distances are seen to affect the strength of each CTRZ and the corner swirling flow pattern, though the bulk flow structure did not change significantly.
The dome recession shows a clear impact on the expansion of swirling flow generated by a single swirler. As the dome recession distance increases, the expansion angle of the swirling jet reduces significantly for the unconfined cases.
A phenomenological description is discussed to understand the reason for the periodically alternating CTRZ pattern observed in the experimental results of the 5-swirler arrays.
Riblet Application in Compressors: Towards Efficient Blade Design?
Authors: Hergt A. , Hage W. , Grund S. , Steinert W. , Terhorst M. , Schongen F. , Wilke Y. 
Published: September 2014

Nowadays, modern axial compressors have already reached a very high level of development. The current study is focused on the question, if the application of riblets on the surfaces of a highly efficient modern compressor blade can be a further step towards more efficient blade design. Therefore, a highly loaded compressor cascade has been designed and optimized specifically for low Reynolds number conditions, as encountered at high altitudes and under consideration of the application of riblets. The optimization was performed at a Mach number of 0.6 and a Reynolds number of 1.5×105. Two objective functions were used. The aim of the first objective function was to minimize the cascade losses at the design point and at incidence angles of +5 and −5 degrees. The intention of the second objective function was to achieve a smooth distribution of the skin friction coefficient on the suction side of the blade by influencing the blade curvature in order to apply riblets. The MISES flow solver as well as the DLR optimizer “AutoOpti” were used for the optimization process.
The developed compressor cascade was investigated in the transonic cascade wind tunnel of DLR in Cologne, where the Reynolds number was varied in the range of 1.5×105 to 9.0×105. Furthermore, the measurements were carried out at a low turbulence level of 0.8 percent and at a high turbulence level of 4 percent, representative for high pressure compressor stages. The measurement program was divided into two parts. The first part consisted of the investigation of the reference cascade. In the second part of the study riblets were applied on suction and pressure side of the cascade blades; two different manufacturing techniques, a rolling and a coating technique were applied. The rolling technique provides riblets with a width of 70 μm and the coated riblets have a width of 50 μm.
The wake measurements were performed using a 3-hole probe at midspan of the cascade in order to determine the resulting losses of the reference blade and the blades with applied riblets. The detailed analysis of the measurements shows, that the riblets have only a slight influence on the viscous losses in the case of the compressor application in this study. Finally, these results are discussed and assessed against the background of feasibility and effort of riblet applications within the industrial design and manufacturing process.
Methodology to Characterize Heat Transfer Phenomena in Small Automotive Turbochargers: Experiments and Modelling Based Analysis
Authors: Serrano J. R. , Olmeda P. , Arnau F. J. , Dombrovsky A. , Smith L. 
Published: September 2014

These days great effort is devoted to the study of turbocharging in order to minimize fuel consumption and pollutant emissions of turbocharged reciprocating engines. Among all the processes taking place in small automotive turbochargers, the heat transfer phenomenon is one of the least analysed in a systematic way. However turbocharger heat transfer phenomena are very important at low engine loads. An accurate prediction of gas temperatures at turbine and compressor outlet and fluid temperatures at the water and oil outlet ports is not possible without considering heat transfer phenomena in the turbocharger.
In the present work a comprehensive study of these phenomena is presented, showing their relevance compared to gas enthalpy variations through the turbomachinery. The study provides an experimental methodology to consider the different heat fluxes in the turbocharger and modelling them by means of a lumped capacitance heat transfer model.
The input data required for the model is obtained experimentally by a proper combination of both steady and transient tests. These tests are performed in different test benches, in which compressible fluids (gas) and incompressible fluids (oil) are used in a given sequence. The experimental data allows developing heat transfer correlations for the different turbocharger elements. These correlations take into account all the possible heat fluxes, discriminating between internal and external heat transfer.
In order to analyse the relative importance of heat transfer phenomena in the predictability of the turbocharger performance and the different related variables; model results, in hot and cold conditions, have been compared with those provided by the standard technique, consisting on using look up maps of the turbocharger.
The analysis of these results evidences the highly diabatic operative areas of the turbocharger and it provides clearly ground rules for using hot or cold maps. In addition, paper conclusions advise about using or not a heat transfer model, depending on the turbocharger variables and the operative conditions that one desires to predict.
Exploiting Waste Heat in Small and Medium-Sized Combined Heat and Power Plants Using Steam Injection
Authors: Arnold Stephan , Schatz Markus 
Published: September 2014

Combined heat and power generation (CHP) is a way of providing both electric power and thermal heat for industrial and domestic facilities at high fuel efficiencies. Often small and medium sized gas powered internal combustion (IC) engines, rated at electric power outputs of 50–600 kW, are used for such applications. During the time when the available thermal heat is used, the fuel efficiency of such CHP plants is very high, but it drops to the efficiencies of simple power generation when there is no heat demand, e.g. during summer. In these cases, the exhaust heat is blown off, especially as CHP units are mainly heat-lead, i.e. designed to cover the heat demand rather than the demand for electrical power. Moreover, as the cooling water heat rejection is also more difficult at elevated ambient temperatures, these units are then operated at part load or even switched off, hence having a lower degree of capacity utilization.
The approach of the work presented here is to replace the turbocharger system commonly used for IC engines and to use an electric driven compression device instead, while the turbine serves to generate additional electric power from the exhaust gas.
Furthermore, for periods with low thermal heat demand, steam is generated from the turbine exhaust heat. The steam is injected in front of the turbine in order to increase the turbine work output further. Thus, at least part of the exhaust heat available is used and the power output as well as the electric efficiency is increased. In the present work, two configurations of the described setup using a medium sized gas powered IC engine CHP unit are modeled in order to assess the impact on plant performance and the characteristics of such a facility. In both cases the engine cooling circuit is integrated. Depending on the configuration used, the plant power output increases by up to 7% only because of the power turbine. Additional steam injection to use the waste heat increases the power output further. The relative electric efficiency increase with steam injection is in the range of 3–5%. Apart from the higher output of electric power, this approach allows longer operating hours to be achieved, as the exhaust heat available is utilized and the heat load for the cooling water circuit is reduced.
A Harmonic Balance Technique for Multistage Turbomachinery Applications
Authors: Frey Christian , Ashcroft Graham , Kersken Hans-Peter , Voigt Christian 
Published: September 2014

This article describes a nonlinear frequency domain method for the simulation of unsteady blade row interaction problems across several blade rows in turbomachinery. The capability to efficiently simulate such interactions is crucial for the improvement of the prediction of blade vibrations, tonal noise, and the impact of unsteadiness on aerodynamic performance.
The simulation technique presented here is based on the harmonic balance approach and has been integrated into an existing flow solver. A nontrivial issue in the application of harmonic balance methods to turbomachinery flows is the fact that various fundamental frequencies may occur simultaneously in one relative system, each one being due to the interaction of two blade rows. It is shown that, considering the disturbances corresponding to different fundamental frequencies as mutually uncoupled, one can develop an unsteady simulation method which from a practial view point turns out to be highly attractive. On the one hand, it is possible to take into account arbitrarily many nonlinear interaction terms. On the other, the computational efficiency can be increased considerably once it is known that the nonlinear coupling between certain subsets of the harmonics plays only a minor role.
To validate the method and demonstrate its accuracy and efficiency a multistage compressor configuration is simulated using both the method described in this article and a conventional time-domain solver.
High Efficiency Cavity Winglets for High Pressure Turbines
Authors: Coull John D. , Atkins Nicholas R. , Hodson Howard P. 
Published: September 2014

The flow leaking over the tip of a high pressure turbine blade generates significant aerodynamic losses as it mixes with the freestream flow. This paper examines the potential for reducing these losses using winglets with recessed cavities on the tip. These features combine the loss-reduction mechanisms of cavity tips, which reduce the discharge coefficient, and winglet overhangs, which reduce the mixing Mach number, leakage flow angle mismatch, and the driving pressure ratio. RANS calculations are performed for an un-cooled HP rotor blade to explore the cavity-winglet design space and examine the impact on the aerothermal performance of the blade.
Relative to a plain-tip design, a cavity tip can reduce the sensitivity to clearance by around 30%. Similar performance can be achieved using a flat-tip winglet with an overhang around the whole blade perimeter. However, by adding a cavity to this winglet it is possible to out-perform the cavity tip at all clearances, and reduce the sensitivity to clearance by 46% relative to the plain tip. This sensitivity is equivalent to a two-fin attached shroud, but the winglet blade will exhibit lower stress and require less coolant flow. Furthermore this cavity-winglet may offer some cooling advantages over the cavity tip.
Design of an Axial Impulse Turbine for Enthalpy Drop Recovery
Authors: Morgese Gaetano , Torresi Marco , Fortunato Bernardo , Camporeale Sergio Mario 
Published: September 2014

In industrial process plants, often there is the need to reduce the pressure of the operating flow. Generally this is performed by means of valves which expand the flow without any work done. The same operation could be performed by replacing these valves with turbines, with the advantage of energy recovery, hence improving the overall efficiency of the system.
In this work, a simple and rapid method is shown in order to design a single stage, straight bladed, axial impulse turbine for enthalpy recovery. Assigned the desired flow rate and the minimum power output, the turbine design is performed according to a one-dimensional study into which loss effects are considered by means of appropriate coefficients. From the one-dimensional analysis the heights, the pitch angle, the inlet and outlet angles of both rotor and stator blades are obtained. Actually, the rotor and stator blade profiles are defined by means of several analytical functions. The blade design is then validated by means of CFD simulations. The definition of loss coefficients and blade geometrical parameters is clearly an iterative process, which needs to be repeated until convergence is reached. Furthermore, by means of fully 3D simulations, the effect of the rotor-stator distance is investigated in order to maximize the turbine performance.
Application of Gas Path Analysis to Compressor Diagnosis of an Industrial Gas Turbine Using Field Data
Authors: Blinstrub J. , Li Y. G. , Newby M. , Zhou Q. , Stigant G. , Pilidis P. , Hönen H. 
Published: September 2014

Maintenance cost is one of the major life cycle costs of gas turbine engines. To reduce the maintenance costs, the maintenance should be changed from preventive (or scheduled) maintenance to predictive (or condition-based) maintenance where condition monitoring and diagnostics become crucially important.
This paper represents the application of a gas path diagnostic technique, Gas Path Analysis, to the diagnostic analysis of an aero-derivative gas turbine (GE LM2500+) operated by Manx Electricity Authority in the Isle of Man, UK. In the application, an engine thermodynamic model is created and adapted to the performance of the engine using field data obtained at different operating conditions. Different data pre-processing methods are presented and compared in the diagnostic analysis. The uncertainty of measurement data is analysed and the most suitable measurements are identified in the prediction of key gas path component degradation. A non-linear GPA diagnostic analysis provides promising results for the prediction of compressor degradation and the performance improvement due to a compressor water washing. Such diagnostic information would be very useful for maintenance engineers to optimise their maintenance activities including overhauls and compressor washing.