bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Turbine Rotor Disc Repair-Case History
Authors: Mazur Zdzislaw , Kubiak Janusz 
Published: December 2014

The 20.65 MW gas turbine experienced catastrophic damage. The failure occurred at the first stage buckets and resulted in damage of the all buckets of this stage. Five rotor disc grooves were also seriously damaged. Additionally, all second stage buckets, first and second stage nozzles, shroud segments, the No 2 bearing casing (turbine side), compressor moving blades, and other elements were damaged. Due to urgent power generation needs, it was decided to repair a seriously damaged stage 1 rotor disc in-situ, and replace all the other damaged parts.
The development of a propietary welding technology for the in-situ repair of the five damaged disc grooves without disc disassembly, and of in-situ disc grooves’ mechanized machining is fully described. The repair process included the removal of damaged grooves, method of groove restoration by welding deposition, stress relief and groove machining to recover their original geometry. After rotor disc repair and assembly, the rotor was put back into service. The approach to the repair of the rotor disc damage has been successful. It enabled significant reductions in expenditure on replacement parts and a reduction of outage time to be achived.
Three Dimensional Unsteady Flow for an Oscillating Turbine Blade and the Influence of Tip Leakage
Authors: Bell D. L. , He L. 
Published: December 2014

The results of two investigations, conducted on the aerodynamic response of a turbine blade oscillating in a three dimensional bending mode, are presented in this paper.
The first is an experimental and computational study, designed to produce detailed three dimensional test cases for aeroelastic applications and examine the ability of a 3D time-marching Euler method to predict the relevant unsteady aerodynamics. Extensive blade surface unsteady pressure measurements were obtained for a range of reduced frequency, from a test facility with clearly defined boundary conditions, Bell & He (1997). The test data exhibits a significant three dimensional effect, whereby the amplitude of the unsteady pressure response at different spanwise positions is largely insensitive to the local bending amplitude. The inviscid numerical scheme successfully captured this behaviour, and a good qualitative and quantitative agreement with the test data was achieved for the full range of reduced frequency. In addition, the issue of linearity is addressed and both experimental and numerical tests demonstrate a linear behaviour of the unsteady aerodynamics.
The second, an experimental investigation, considers the influence of tip leakage on the unsteady pressure response of an oscillating turbine blade. Results are provided for three tip clearances. The steady flow measurements show marked increases in the size and strength of the tip leakage vortex for the larger tip gaps and deviations in the blade loading towards the tip section. The changes in tip gap also caused distinct trends in the amplitude of the unsteady pressure at 90% span, which were consistent with those observed for steady flow blade loading. It is the authors opinion, that the existence of these trends in unsteady pressure warrants further investigation into the influence of tip leakage upon the local unsteady flow and aerodynamic damping.
The Influence of Tailboards on Unsteady Measurements in a Linear Cascade
Authors: Ott P. , Norryd M. , Bölcs A. 
Published: December 2014

The present paper shows the comparison between steady-state and unsteady results from two versions of a flow solver and measurements in a linear cascade at transonic flow conditions for forced vibration of a single blade.
Experiments have been conducted in a linear test facility with a cascade composed of five turbine blades. The center blade was forced to oscillate in a pure bending mode with a frequency of 160 Hz. Tailboards are fixed in this test facility at the trailing edges of the border blades to create a periodic flow at the outlet of the cascade.
A 2D inviscid flow solver for unsteady flows through vibrating blade rows was adapted to simulate the flow conditions in the linear cascade.
The initial adaptation of the flow solver was the limitation to only one vibrating blade. Comparisons with measurements showed discrepancies which were hypothesized to be due to the presence of the tailboards which can create reflections of pressure waves and shocks.
Therefore, as a second modification of the program, the periodic boundaries downstream of the blades were replaced by solid walls.
Based on these computations it can be concluded that for transonic flows the tailboards have a significant influence on both the steady-state and unsteady flow in the outlet region as well as on the blade in the shock region. In particular, the unsteady data measured in a linear cascade has to be analyzed very carefully to estimate the influence of the tailboards.
Internal Reforming Solid Oxide Fuel Cell-Gas Turbine Combined Cycles (IRSOFC-GT): Part A — Cell Model and Cycle Thermodynamic Analysis
Authors: Massardo A. F. , Lubelli F. 
Published: December 2014

The aim of this work is to investigate the performance of Internal Reforming Solid Oxide Fuel Cell (IRSOFC) and Gas Turbine (GT) combined cycles.
To study complex systems involving IRSOFC a mathematical model has been developed that simulates the fuel cell steady-state operation. The model, tested with data available in literature, has been used for a complete IRSOFC parametric analysis taking into account the influence of cell operative pressure, cell and stream temperatures, fuel-oxidant flow rates and composition, etc.
The analysis of IRSOFC-GT combined cycles has been carried out by using the ThermoEconomic Modular Program TEMP (Agazzani and Massardo, 1997). The code has been modified to allow IRSOFC, external reformer and flue gas condenser performance to be taken into account. Using as test case the IRSOFC-GT combined plant proposed by Harvey and Richter (1994) the capability of the modified TEMP code has been demonstrated.
The thermodynamic analysis of a number of IRSOFC-GT combined cycles is presented and discussed, taking into account the influence of several technological constraints. The results are presented for both atmospheric and pressurised IRSOFC.
Diffusion Bonding of CMSX-4 to Udimet 720 Using PVD-Coated Interfaces and HIP
Authors: Larker Richard , Ockborn Johan , Selling Bengt 
Published: December 2014

There is an increasing interest in development of manufacturing methods for Dual Property BLISKs, consisting of creep resistant airfoils and fatigue resistant disks bonded together by a durable joint. Optimum heat treatments are, however, very different for creep resistant single crystal CMSX-4 and fatigue resistant poly-crystalline Udimet 720 selected in this study, but fortunately the first ageing treatment for CMSX-4 (1140°C, 2–6h, AC) is similar to the partial solution treatment of U 720 HS2 (1115°C, 4h, OQ).
Based on this, diffusion bonding was performed by HIP at 1120°C and 200 MPa argon pressure for 4h, followed by cooling to 400°C. Subsequently, a shortened Udimet 720 HS2 two-step ageing treatment was adopted by heating to 650°C for 6h followed by cooling to 400°C, heating to 760°C for 2h, and finally cooling to R.T. under remaining HIP pressure.
Plasma etching followed by thin (80 nm) PVD coating with either nickel or titanium were used to clean and protect the polished surfaces before joining. The selection of coatings was governed by the possibility to reduce oxidized nickel by flushing with hydrogen at 330°C during evacuation of the HIP capsules, and by the large solubility of oxygen in titanium.
Hot tensile testing was performed at 750°C on both joined and reference materials subjected to the modified heat treatment. Initially solution treated Udimet 720 and CMSX-4 comprised the reference materials. The testing showed that joints with Ni-PVD coatings were almost as strong as Udimet 720 (although with very limited elongation), while the joints with Ti-PVD coatings were weaker.
Experimental Analysis and Numerical Simulation of the Flow Field in Turbine Scrolls
Authors: Menter Uwe W. , Klima Thomas , Pfost Heiner 
Published: December 2014

A large selection of one- and two-dimensional methods can be used to calculate the scroll geometries. This paper examines the consequences of different scroll geometry parameters under various flow configurations, including the influence of components in the scroll flow field.
A combination of arrangements of the various components was investigated, (scroll/nozzle/rotor, scroll/nozzle/stator, scroll/vane support/rotor, scroll/vane support/stator), to see how the flow varied. In this particular case a frictionless scroll was designed. The turbine operates with a gas fluid. Using a non-invasive laser two-focus technique and wall pressure drillings the flow field was measured over three scroll cross sections and over its extent at φ = 186° up to φ = 211°. The theoretical analysis was performed on a computer using a commercial 3D finite element programme. Using the programme enables the theoretical flow fields of various scroll geometries to be calculated. The validity of the calculations can be assessed by comparing the theoretical calculations with the above mentioned measurements.
The measurements show that by using a rotor the flow field inside the scroll remains uninfluenced by the vane support and nozzle. Measurable differences appear when the rotor is replaced by a stator, these results are confirmed by the computer program. The calculations also show that the scroll geometry has an important effect on the development of the flow field.
Multiscale bilateral filtering for improving image quality in digital breast tomosynthesis
Authors: Lu Yao , Chan Heang‐Ping , Wei Jun , Hadjiiski Lubomir M. , Samala Ravi K. 
Published: December 2014

Purpose:Detection of subtle microcalcifications in digital breast tomosynthesis (DBT) is a challenging task because of the large, noisy DBT volume. It is important to enhance the contrast‐to‐noise ratio (CNR) of microcalcifications in DBT reconstruction. Most regularization methods depend on local gradient and may treat the ill‐defined margins or subtle spiculations of masses and subtle microcalcifications as noise because of their small gradient. The authors developed a new multiscale bilateral filtering (MSBF) regularization method for the simultaneous algebraic reconstruction technique (SART) to improve the CNR of microcalcifications without compromising the quality of masses.Methods:The MSBF exploits a multiscale structure of DBT images to suppress noise and selectively enhance high frequency structures. At the end of each SART iteration, every DBT slice is decomposed into several frequency bands via Laplacian pyramid decomposition. No regularization is applied to the low frequency bands so that subtle edges of masses and structured background are preserved. Bilateral filtering is applied to the high frequency bands to enhance microcalcifications while suppressing noise. The regularized DBT images are used for updating in the next SART iteration. The new MSBF method was compared with the nonconvex total p‐variation (TpV) method for noise regularization with SART. A GE GEN2 prototype DBT system was used for acquisition of projections at 21 angles in 3° increments over a ±30° range. The reconstruction image quality with no regularization (NR) and that with the two regularization methods were compared using the DBT scans of a heterogeneous breast phantom and several human subjects with masses and microcalcifications. The CNR and the full width at half maximum (FWHM) of the line profiles of microcalcifications and across the spiculations within their in‐focus DBT slices were used as image quality measures.Results:The MSBF method reduced contouring artifacts and enhanced the CNR of microcalcifications compared to the TpV method, thus preserving the image quality of the structured background. The MSBF method achieved the highest CNR of microcalcifications among the three methods. The FWHM of the microcalcifications and mass spiculations resulting from the MSBF method was comparable to that without regularization, and superior to that of the TpV method.Conclusions:The SART regularized by the multiscale bilateral filtering method enhanced the CNR of microcalcifications and preserved the sharpness of microcalcifications and spiculated masses. The MSBF method provided better image quality of the structured background and was superior to TpV and NR for enhancing microcalcifications while preserving the appearance of mass margins.
Commissioning the neutron production of a Linac: Development of a simple tool for second cancer risk estimation
Authors: Romero‐Expósito M. , Sánchez‐Nieto B. , Terrón J. A. , Lopes M. C. , Ferreira B. C. , Grishchuk D. , Sandín C. , Moral‐Sánchez S. , Melchor M. , Domingo C. , Gómez F. , Sánchez‐Doblado F. 
Published: December 2014

Purpose:Knowing the contribution of neutron to collateral effects in treatments is both a complex and a mandatory task. This work aims to present an operative procedure for neutron estimates in any facility using a neutron digital detector.Methods:The authors’ previous work established a linear relationship between the total second cancer risk due to neutrons (TRn) and the number of MU of the treatment. Given that the digital detector also presents linearity with MU, its response can be used to determine the TRn per unit MU, denoted as m, normally associated to a generic Linac model and radiotherapy facility. Thus, from the number of MU of each patient treatment, the associated risk can be estimated. The feasibility of the procedure was tested by applying it in eight facilities; patients were evaluated as well.Results:From the reading of the detector under selected irradiation conditions, m values were obtained for different machines, ranging from 0.25 × 10−4% per MU for an Elekta Axesse at 10 MV to 6.5 × 10−4% per MU for a Varian Clinac at 18 MV. Using these values, TRn of patients was estimated in each facility and compared to that from the individual evaluation. Differences were within the range of uncertainty of the authors’ methodology of equivalent dose and risk estimations.Conclusions:The procedure presented here allows an easy estimation of the second cancer risk due to neutrons for any patient, given the number of MU of the treatment. It will enable the consideration of this information when selecting the optimal treatment for a patient by its implementation in the treatment planning system.
In Vitro
Activities of Combinations of Rifampin with Other Antimicrobials against Multidrug-Resistant Acinetobacter baumannii
Authors: Bai Yan , Liu Bin , Wang Tianlin , Cai Yun , Liang Beibei , Wang Rui , Liu Youning , Wang Jin 
Published: December 2014

ABSTRACT

The antimicrobial treatment of multidrug-resistant (MDR)
Acinetobacter baumannii
infections has become a great challenge for medical staff all over the world. Increasing numbers of MDR
A. baumannii
infections have been identified and reported, but effective clinical treatments for them are decreasing. The objective of this study was to investigate the
in vitro
activities of combinations of rifampin (an established antimicrobial) and other antimicrobials, including biapenem, colistin, and tigecycline, against 73 clinical isolates of MDR
A. baumannii
. In total, 73 clinical isolates of MDR
A. baumannii
were collected from two A-level general hospitals in Beijing, and the MICs of rifampin, biapenem, colistin, and tigecycline were determined. The checkerboard method was used to determine the fractional inhibitory concentration indices (FICIs), that is, whether the combinations acted synergistically against these isolates. The MIC
50
, MIC
90
, and MIC
range
of rifampin combined with biapenem, colistin, and tigecycline against the isolates were clearly lower than those for four antimicrobials (rifampin, biapenem, colistin, and tigecycline) that were used alone. Combinations of rifampin with biapenem, colistin, and tigecycline individually demonstrated the following interactions: synergistic interactions (FICI ≤ 0.5) for 31.51%, 34.25%, and 31.51% of the isolates, partially synergistic interactions (0.5 < FICI < 1) for 49.31%, 43.83%, and 47.94% of the isolates, and additive interactions (FICI = 1) for 19.18%, 21.92%, and 20.55% of the isolates, respectively. There were no indifferent (1 < FICI < 4) or antagonistic (FICI ≥ 4) interactions. Therefore, combinations of rifampin with biapenem, colistin, or tigecycline may be future therapeutic alternatives for the treatment of MDR
A. baumannii
infections.
The Efflux Pump Inhibitor Timcodar Improves the Potency of Antimycobacterial Agents
Authors: Grossman Trudy H. , Shoen Carolyn M. , Jones Steven M. , Jones Peter L. , Cynamon Michael H. , Locher Christopher P. 
Published: December 2014

ABSTRACT

Previous studies indicated that inhibition of efflux pumps augments tuberculosis therapy. In this study, we used timcodar (formerly VX-853) to determine if this efflux pump inhibitor could increase the potency of antituberculosis (anti-TB) drugs against
Mycobacterium tuberculosis
in
in vitro
and
in vivo
combination studies. When used alone, timcodar weakly inhibited
M. tuberculosis
growth in broth culture (MIC, 19 μg/ml); however, it demonstrated synergism in drug combination studies with rifampin, bedaquiline, and clofazimine but not with other anti-TB agents. When
M. tuberculosis
was cultured in host macrophage cells, timcodar had about a 10-fold increase (50% inhibitory concentration, 1.9 μg/ml) in the growth inhibition of
M. tuberculosis
and demonstrated synergy with rifampin, moxifloxacin, and bedaquiline. In a mouse model of tuberculosis lung infection, timcodar potentiated the efficacies of rifampin and isoniazid, conferring 1.0 and 0.4 log
10
reductions in bacterial burden in lung, respectively, compared to the efficacy of each drug alone. Furthermore, timcodar reduced the likelihood of a relapse infection when evaluated in a mouse model of long-term, chronic infection with treatment with a combination of rifampin, isoniazid, and timcodar. Although timcodar had no effect on the pharmacokinetics of rifampin in plasma and lung, it did increase the plasma exposure of bedaquiline. These data suggest that the antimycobacterial drug-potentiating activity of timcodar is complex and drug dependent and involves both bacterial and host-targeted mechanisms. Further study of the improvement of the potency of antimycobacterial drugs and drug candidates when used in combination with timcodar is warranted.
Novel Quorum-Quenching Agents Promote Methicillin-Resistant Staphylococcus aureus (MRSA) Wound Healing and Sensitize MRSA to β-Lactam Antibiotics
Authors: Kuo David , Yu Guanping , Hoch Wyatt , Gabay Dean , Long Lisa , Ghannoum Mahmoud , Nagy Nancy , Harding Clifford V. , Viswanathan Rajesh , Shoham Menachem 
Published: December 2014

ABSTRACT

The dwindling repertoire of antibiotics to treat methicillin-resistant
Staphylococcus aureus
(MRSA) calls for novel treatment options. Quorum-quenching agents offer an alternative or an adjuvant to antibiotic therapy. Three biaryl hydroxyketone compounds discovered previously (F1, F12, and F19; G. Yu, D. Kuo, M. Shoham, and R. Viswanathan, ACS Comb Sci 16:85–91, 2014) were tested for efficacy in MRSA-infected animal models. Topical therapy of compounds F1 and F12 in a MRSA murine wound infection model promotes wound healing compared to the untreated control. Compounds F1, F12, and F19 afford significant survival benefits in a MRSA insect larva model. Combination therapy of these quorum-quenching agents with cephalothin or nafcillin, antibiotics to which MRSA is resistant in monotherapy, revealed additional survival benefits. The quorum-quenching agents sensitize MRSA to the antibiotic by a synergistic mode of action that also is observed
in vitro
. An adjuvant of 1 μg/ml F1, F12, or F19 reduces the MIC of nafcillin and cephalothin about 50-fold to values comparable to those for vancomycin, the antibiotic often prescribed for MRSA infections. These findings suggest that it is possible to resurrect obsolete antibiotic therapies in combination with these novel quorum-quenching agents.
Novel Glycosylated VEGF Decoy Receptor Fusion Protein, VEGF-Grab, Efficiently Suppresses Tumor Angiogenesis and Progression
Authors: Lee Jung-Eun , Kim Chan , Yang Hannah , Park Intae , Oh Nuri , Hua Serenus , Jeong Haneul , An Hyun Joo , Kim Sun Chang , Lee Gyun Min , Koh Gou Young , Kim Ho Min 
Published: December 2014

Abstract
Antiangiogenic therapies targeting VEGFA have been commonly used in clinics to treat cancers over the past decade. However, their clinical efficacy has been limited, with drawbacks including acquisition of resistance and activation of compensatory pathways resulting from elevated circulating VEGFB and placental growth factor (PlGF). To bypass these disadvantages, we developed a novel glycosylated soluble decoy receptor fusion protein, VEGF-Grab, that can neutralize VEGFA, VEGFB, and PlGF. VEGF-Grab has the second and third immunoglobulin (Ig)-like domains of VEGF receptor 1 (VEGFR1) fused to IgG1 Fc, with three potential glycosylation sites introduced into the third Ig-like domain of VEGF-Grab by mutagenesis. Compared with VEGF-Trap, VEGF-Grab showed more potent decoy activity against VEGF and PlGF, mainly attributed to the VEGFR1 backbone. Most importantly, the negatively charged O-glycans attached to the third Ig-like domain of VEGFR1 counterbalanced the originally positively charged VEGFR1 backbone, minimizing nonspecific binding of VEGF-Grab to the extracellular matrix, and resulting in greatly improved pharmacokinetic profile. These advancements led to stronger and more durable antiangiogenic, antitumor, and antimetastatic efficacy in both implanted and spontaneous tumor models as compared with VEGF-Trap, while toxicity profiles were comparable with VEGF-Trap. Collectively, our results highlight VEGF-Grab as a promising therapeutic candidate for further clinical drug development. Mol Cancer Ther; 14(2); 470–9. ©2014 AACR.
An evidence-based review of oral magnesium supplementation in the preventive treatment of migraine
Authors: Teigen Levi , Boes Christopher J 
Published: December 2014

Background Migraine is an incompletely understood, debilitating disorder that lacks a universally effective treatment. Magnesium participates in a variety of biochemical processes related to migraine pathophysiology, and a deficiency could contribute to migraine development. Methods A review of the literature from 1990 to the present on magnesium and migraine was conducted. Review The authors identified 16 studies aimed at magnesium status assessment in migraine, and four intervention trials assessing the efficacy of oral magnesium supplementation, independent of other therapies, in the prevention of migraine. Conclusion The strength of evidence supporting oral magnesium supplementation is limited at this time. With such limited evidence, a more advantageous alternative to magnesium supplementation, in patients willing to make lifestyle changes, may be to focus on increasing dietary magnesium intake.