bluuebunny/crossref_metadata_2025_split huggingface dataset:
Component Development for the KTT MKI Automotive Gas Turbine
Authors: Holmqvist Göran , Malmrup Lars 
Published: April 2015

The KTT system is a gas turbine propulsion system designed especially for the automotive application. It’s main features are the three turbines on three different shafts and the close integration of the turbine and transmission into one unit.
The first experimental engine, the MkI, based on this system is being developed by United Turbine, a subsidiary to AB Volvo, in Sweden. This paper describes some results of the development of the main components for this engine; the compressor, the turbines and the heat exchanger system. Details on test equipment are given.
The results presented are not final and development continues. These results also provide a base for future engine designs.
Particulate Flow in the Rotor and Stator Elements of Turbomachines
Authors: Abdel Azim A. F. , Rouleau W. T. 
Published: April 2015

In order to examine both primary and secondary erosion of turbomachines, two examples were studied: the impeller of a centrifugal compressor and the stationary straight infinite cascade. The first example was examined when particulates of large diameters bombarded its internal surface, thus providing a primary erosion pattern. An inviscid flow is assumed since the trajectories of large diameter particles are slightly influenced by viscous effects. Tracing these trajectories for silica and alumina particles defined four areas on the internal surfaces of the impeller which experienced the highest rate of material removal due to the successvie impacts. The viscous model of a centrifugal compressor is also under investigation by the authors.
The stationary infinite cascade of a typical turboexpander was subjected to fine particulate impacts. These fine particles were greatly influenced by both the viscous effects and secondary flow. Thus three-dimensional viscous flow was defined experimentally using a laser-Doppler anemometer (LDA). The pressure surface, especially the turning section, suffered from the highest erosion damage. These results compared favorably with the experimental results of the Ruston and Hornsby turbine operating with Greta Coal. The erosion rates of the first stage Ruston Turbine after 124.8 hours of operation showed similar results.
Comparison of Partial vs Full Admission for Small Turbines at Low Specific Speeds
Authors: Macchi Ennio , Lozza Giovanni 
Published: April 2015

Several methods are available for the optimization of basic design parameters and the preliminary efficiency prediction of axial flow turbine stages. However, their application is often questionable for stages having low specific speed and/or small volume flow rates. In particular, the question may arise whether a better performance is achieved by a partial admission, impulse stage or by a full admission reaction stage having lower blade height.
The paper firstly reviews the available loss correlation methods applicable to partial admission turbines, then a comparison is performed between the efficiency achievable by partial and full admission stages designed for the same operating conditions. The turbine design procedure for both options is fully automatized by an efficiency optimization method similar to the one described in previous authors’ papers.
The results of calculations are presented in the paper as a function of similarity parameters (specific speed, size parameter, expansion ratio). It is found that the results obtained with different correlations are relatively similar for “conventional” turbine stages (low expansion ratio, moderate size parameters), while important differences take place for very small sizes and/or in presence of important compressibility effects.
The presented results can be useful: 1) to decide whether selecting full or partial admission solutions; 2) to optimize the degree of admission and the other basic design parameters, and 3) to predict with reasonable accuracy the stage efficiency.
A Comparison Between Full and Simplified Navier-Stokes Equation Solutions for Rotating Blade Cascade Flow on S1 Stream Surface of Revolution
Authors: Naixing Chen , Fengxian Zhang 
Published: April 2015

A method for solving the Navier-Stokes equations of the rotating blade cascade flow on S1 stream surface of revolution is developed in the present paper.
In this paper a complete set of full and simplified Navier-Stokes equations is given which includes stream-function equation, energy equation and entropy equation, equation of state for a perfect gas, formula for estimating density and formulas for calculating viscous forces, work done by viscous force, dissipation function and heat-transfer term.
A comparison between the full and the simplified Navier-Stokes equations is made. The viscous terms of both full and simplified Navier-Stokes equation solutions are also compared in the present paper. The comparison shows that the simplified Navier-Stokes equations are applicable.
Onshore Test Method for a 3 Unit 60 MW Gas Turbine-Generator Power Module
Authors: Herdlevaer Johannes , Black Gordon Hugh 
Published: April 2015

There has been an increasing demand for onshore testing of equipment destined for offshore operation.
The justification for this requirement can be summarized as follows:
1. High cost of offshore commissioning where even minor faults detected, constitutes potentially serious problems.
2. Consequenses of delay of platform start-up are enormous.
3. Skilled experienced personel and diagnostic equipment is available onshore, and rectification of new units will benefit from the existence of previous experience.
4. Spare and renewal parts availability.
This paper describes the method for string testing of a 3 unit 60 mw utility gasturbine-generator power module built for the gullfaks A platform in the Norwegian sector of the north sea.
It describes the test facility and test equipment set up and also the test program which was followed.
At the time of writing the paper the test program was barely initiated, and for that reason the test results will be presented in the form of an addendum to this paper during the meeting.
Dosimetric characterization of a microDiamond detector in clinical scanned carbon ion beams
Authors: Marinelli Marco , Prestopino G. , Verona C. , Verona‐Rinati G. , Ciocca M. , Mirandola A. , Mairani A. , Raffaele L. , Magro G. 
Published: April 2015

Purpose:To investigate for the first time the dosimetric properties of a new commercial synthetic diamond detector (PTW microDiamond) in high‐energy scanned clinical carbon ion beams generated by a synchrotron at the CNAO facility.Methods:The detector response was evaluated in a water phantom with actively scanned carbon ion beams ranging from 115 to 380 MeV/u (30–250 mm Bragg peak depth in water). Homogeneous square fields of 3 × 3 and 6 × 6 cm2 were used. Short‐ and medium‐term (2 months) detector response stability, dependence on beam energy as well as ion type (carbon ions and protons), linearity with dose, and directional and dose‐rate dependence were investigated. The depth dose curve of a 280 MeV/u carbon ion beam, scanned over a 3 × 3 cm2 area, was measured with the microDiamond detector and compared to that measured using a PTW Advanced Markus ionization chamber, and also simulated using fluka Monte Carlo code. The detector response in two spread‐out‐Bragg‐peaks (SOBPs), respectively, centered at 9 and 21 cm depths in water and calculated using the treatment planning system (TPS) used at CNAO, was measured.Results:A negligible drift of detector sensitivity within the experimental session was seen, indicating that no detector preirradiation was needed. Short‐term response reproducibility around 1% (1 standard deviation) was found. Only 2% maximum variation of microDiamond sensitivity was observed among all the evaluated proton and carbon ion beam energies. The detector response showed a good linear behavior. Detector sensitivity was found to be dose‐rate independent, with a variation below 1.3% in the evaluated dose‐rate range. A very good agreement between measured and simulated Bragg curves with both microDiamond and Advanced Markus chamber was found, showing a negligible LET dependence of the tested detector. A depth dose curve was also measured by positioning the microDiamond with its main axis oriented orthogonally to the beam direction. A strong distortion in Bragg peak measurement was observed, confirming manufacturer recommendation on avoiding such configuration. Very good results were obtained for SOBP measurements, with a difference below 1% between measured and TPS‐calculated doses. The stability of detector sensitivity in the observation period was within the experimental uncertainty.Conclusions:Dosimetric characterization of a PTW microDiamond detector in high‐energy scanned carbon ion beams was performed. The results of the present study showed that this detector is suitable for dosimetry of clinical carbon ion beams, with a negligible LET and dose‐rate dependence.
Individual, Social, and Neighborhood Associations With Sitting Time Among Veterans
Authors: Millstein Rachel A. , Hoerster Katherine D. , Rosenberg Dori E. , Nelson Karin M. , Reiber Gayle , Saelens Brian E. 
Published: April 2015

Background:Sedentary behavior is an increasingly recognized health risk factor, independent of physical activity. Although several correlates of sedentary behavior are known, little research has identified them among U.S. veterans, a population that faces disproportionate chronic disease burden.Methods:A survey was mailed to 1997 randomly selected veterans at a large urban Veterans Affairs medical center in 2012 and remailed in 2013 to nonresponders, resulting in a 40% response rate. We examined individual-, social-, and neighborhood-level factors in association with self-reported sitting time. Factors correlated with sitting time at P < .05 were included in a multiple linear regression model.Results:In the multivariate model, higher depression (B = 7.8), body mass index (B = 5.1), functional impairment (B = 4.2), and self-rated health (B = 68.5) were significantly associated with higher sitting time, and leisure time physical activity (B = –0.10) and being employed (B = –71.3) were significantly associated with lower sitting time.Conclusions:Individual-level, but not social- and neighborhood-level, variables were associated with sitting time in this population. This study identified individual-level targets for reducing sitting time and improving overall health among veterans.
Measurement Considerations of Peak Stepping Cadence Measures Using National Health and Nutrition Examination Survey 2005–2006
Authors: Kang Minsoo , Kim Youngdeok , Rowe David A. 
Published: April 2015

Background:This study examined the optimal measurement conditions to obtain reliable peak cadence measures using the accelerometer-determined step data from the National Health and Nutrition Examination Survey 2005–2006.Methods:A total of 1282 adults (> 17 years) who provided valid accelerometer data for 7 consecutive days were included. The peak 1- and 30-minute cadences were extracted. The sources of variance in peak stepping cadences were estimated using Generalizability theory analysis. A simulation analysis was conducted to examine the effect of the inclusion of weekend days. The optimal number of monitoring days to achieve 80% reliability for peak stepping cadences were estimated.Results:Intraindividual variability was the largest variance component of peak cadences for young and middle-aged adults aged < 60 years (50.55%–59.24%) compared with older adults aged ≥ 60 years (31.62%–41.72%). In general, the minimum of 7 and 5 days of monitoring were required for peak 1- and 30-minute cadences among young and middle-aged adults, respectively, whereas 3 days of monitoring was sufficient for older adults to achieve the desired reliability (0.80). The inclusion of weekend days in the monitoring frame may not be practically important.Conclusions:The findings could be applied in future research as the reference measurement conditions for peak cadences.
Planning Mediates Between Self-Efficacy and Physical Activity Among Motivated Young Adults
Authors: Zhou Guangyu , Wang Dongmei , Knoll Nina , Schwarzer Ralf 
Published: April 2015

Background:Often, motivation to be physically active is a necessary precondition of action but still does not suffice to initiate the target behavior. Instead, motivation needs to be translated into action by a self-regulatory process. Self-efficacy and planning are considered to be useful constructs that help to facilitate such translations.Objective:The aim is to examine the roles of motivation, planning, and self-efficacy as well as the mechanisms that operate in the change of physical activity levels.Methods:In a longitudinal observation study with 249 young adults, self-efficacy, planning, motivation, and physical activity were assessed at 2 points in time, 3 months apart.Results:Planning served as a mediator between self-efficacy and physical activity, controlling for baseline activity. In addition to this indirect effect, a moderator effect was found between self-efficacy and stages of change on planning. The mediation operated only in motivated, but not in unmotivated students.Conclusions:A mediation from self-efficacy via planning to physical activity seems to be likely only when people are motivated to become more active.
Meropenem-Clavulanic Acid Has High
In Vitro
Activity against Multidrug-Resistant Mycobacterium tuberculosis
Authors: Davies Forsman L. , Giske C. G. , Bruchfeld J. , Schön T. , Juréen P. , Ängeby K. 
Published: April 2015

ABSTRACT

We investigated the activity of meropenem-clavulanic acid (MEM-CLA) against 68
Mycobacterium tuberculosis
isolates. We included predominantly multi- and extensively drug-resistant tuberculosis (MDR/XDR-TB) isolates, since the activity of MEM-CLA for resistant isolates has previously not been studied extensively. Using Middlebrook 7H10 medium, all but four isolates showed an MIC distribution of 0.125 to 2 mg/liter for MEM-CLA, below the non-species-related breakpoint for MEM of 2 mg/liter defined by EUCAST. MEM-CLA is a potential treatment option for MDR/XDR-TB.
Clinical Epidemiology and Molecular Analysis of Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Nepal: Characteristics of Sequence Types 131 and 648
Authors: Sherchan Jatan Bahadur , Hayakawa Kayoko , Miyoshi-Akiyama Tohru , Ohmagari Norio , Kirikae Teruo , Nagamatsu Maki , Tojo Masayoshi , Ohara Hiroshi , Sherchand Jeevan B. , Tandukar Sarmila 
Published: April 2015

ABSTRACT

Recently, CTX-M-type extended-spectrum-β-lactamase (ESBL)-producing
Escherichia coli
strains have emerged worldwide. In particular,
E. coli
with O antigen type 25 (O25) and sequence type 131 (ST131), which is often associated with the CTX-M-15 ESBL, has been increasingly reported globally; however, epidemiology reports on ESBL-producing
E. coli
in Asia are limited. Patients with clinical isolates of ESBL-producing
E. coli
in the Tribhuvan University teaching hospital in Kathmandu, Nepal, were included in this study. Whole-genome sequencing of the isolates was conducted to analyze multilocus sequence types, phylotypes, virulence genotypes, O25b-ST131 clones, and distribution of acquired drug resistance genes. During the study period, 105 patients with ESBL-producing
E. coli
isolation were identified, and the majority (90%) of these isolates were CTX-M-15 positive. The most dominant ST was ST131 (
n
= 54; 51.4%), followed by ST648 (
n
= 15; 14.3%). All ST131 isolates were identified as O25b-ST131 clones, subclone H30-Rx. Three ST groups (ST131, ST648, and non-ST131/648) were compared in further analyses. ST648 isolates had a proportionally higher resistance to non-β-lactam antibiotics and featured drug-resistant genes more frequently than ST131 or non-ST131/648 isolates. ST131 possessed the most virulence genes, followed by ST648. The clinical characteristics were similar among groups. More than 38% of ESBL-producing
E. coli
isolates were from the outpatient clinic, and pregnant patients comprised 24% of ESBL-producing
E. coli
cases. We revealed that the high resistance of ESBL-producing
E. coli
to multiple classes of antibiotics in Nepal is driven mainly by CTX-M-producing ST131 and ST648. Their immense prevalence in the communities is a matter of great concern.
In Vitro
Activity of Ceftazidime-Avibactam against 338 Molecularly Characterized Gentamicin-Nonsusceptible Gram-Negative Clinical Isolates Obtained from Patients in Canadian Hospitals
Authors: Denisuik Andrew J. , Karlowsky James A. , Denisuik Tyler , Nichols Wright W. , Keating Thomas A. , Adam Heather J. , Baxter Melanie , Walkty Andrew , Zhanel George G. 
Published: April 2015

ABSTRACT

The mechanism of aminoglycoside resistance among 338 gentamicin-nonsusceptible Gram-negative bacteria (207
Enterobacteriaceae
and 131
Pseudomonas aeruginosa
) was assessed, and the
in vitro
activity of ceftazidime-avibactam against these isolates was determined. Aminoglycoside-modifying enzymes were detected in 91.8% of
Enterobacteriaceae
and 13.7% of
P. aeruginosa
isolates. A single strain of
Klebsiella pneumoniae
harbored a 16S rRNA methylase (ArmA). The ceftazidime-avibactam MIC
90
values were 0.5 μg/ml (MIC, ≤8 μg/ml for 100% of isolates) and 16 μg/ml (MIC, ≤8 μg/ml for 87.8% of isolates) against gentamicin-nonsusceptible
Enterobacteriaceae
and
P. aeruginosa
isolates, respectively.
Plasma and Epithelial Lining Fluid Pharmacokinetics of Ceftolozane and Tazobactam Alone and in Combination in Mice
Authors: Melchers M. J. , Mavridou E. , Seyedmousavi S. , van Mil A. C. , Lagarde C. , Mouton J. W. 
Published: April 2015

ABSTRACT

Ceftolozane is a new cephalosporin with activity against Gram-negative and Gram-positive microorganisms. However, the compound is susceptible to degradation by extended-spectrum beta-lactamases (ESBLs). Tazobactam is an ESBL inhibitor and is combined with ceftolozane to broaden its activity. Surprisingly, although tazobactam has been available for over 20 years, few if any reliable data exist on the tazobactam pharmacokinetic (PK) properties in mice. To evaluate the PK and pharmacodynamic (PD) relationships in mice, the PK properties of tazobactam and ceftolozane were extensively investigated. Thigh-infected neutropenic CD-1 mice were injected intraperitoneally with a single 0.1-ml dose containing ceftolozane, tazobactam, or both compounds. Ceftolozane was applied in 2-fold-increasing doses of 4 mg/kg of body weight to 64 mg/kg alone or in combination. Tazobactam was combined in reverse doses (thus, 64/4 mg/kg, 32/8 mg/kg, etc.) (
n =
2 per time point). In separate validation experiments, ceftolozane-tazobactam was given alone or in combination at 32/8 mg/kg and 8/32 mg/kg (
n =
4 per time point). Plasma samples (one per mouse) and bronchoalveolar lavage samples were collected at up to 12 time points until 6 h after administration. There were no significant differences in the ceftolozane and tazobactam PK alone versus combined, indicating no PK interaction. The PKs were linear and dose proportional for both compounds and showed a good penetration in the epithelial lining fluid. The estimated mean (standard deviation) half-life of ceftolozane was 0.287 h (0.031 h), and that of tazobactam was 0.176 h (0.026), and the
V
was 0.43 liter/kg and 1.14 liter/kg, respectively. The estimates of tazobactam parameters can also be used to (re)interpret PD data.
Efficacy of Tigecycline for Secondary Acinetobacter Bacteremia and Factors Associated with Treatment Failure
Authors: Liou Bo-Huang , Lee Yi-Tzu , Kuo Shu-Chen , Liu Po-Yu , Fung Chang-Phone 
Published: April 2015

ABSTRACT

We describe the clinical outcome of 17 patients with secondary
Acinetobacter
bacteremia whose isolates had a tigecycline MIC of ≤2 mg/liter and who received tigecycline within 2 days of bacteremia onset. The 14-day mortality rate of the tigecycline cohort was 41.2% (7/17), which was significantly higher than that of those receiving other appropriate antimicrobial agents (13.8%, 9/65;
P
= 0.018). However, the percentages of end-stage renal disease and congestive heart failure were higher in the tigecycline cohort. The efficacy of tigecycline was contingent upon the illness severity and bacterial species. Tigecycline should be applied cautiously for treatment of
Acinetobacter
bacteremia.
Azole Drug Import into the Pathogenic Fungus Aspergillus fumigatus
Authors: Esquivel Brooke D. , Smith Adam R. , Zavrel Martin , White Theodore C. 
Published: April 2015

ABSTRACT

The fungal pathogen
Aspergillus fumigatus
causes serious illness and often death when it invades tissues, especially in immunocompromised individuals. The azole class of drugs is the most commonly prescribed treatment for many fungal infections and acts on the ergosterol biosynthesis pathway. One common mechanism of acquired azole drug resistance in fungi is the prevention of drug accumulation to toxic levels in the cell. While drug efflux is a well-known resistance strategy, reduced azole import would be another strategy to maintain low intracellular azole levels. Recently, azole uptake in
Candida albicans
and other yeasts was analyzed using [
3
H]fluconazole. Defective drug import was suggested to be a potential mechanism of drug resistance in several pathogenic fungi, including
Cryptococcus neoformans
,
Candida krusei
, and
Saccharomyces cerevisiae
. We have adapted and developed an assay to measure azole accumulation in
A. fumigatus
using radioactively labeled azole drugs, based on previous work done with
C. albicans
. We used this assay to study the differences in azole uptake in
A. fumigatus
isolates under a variety of drug treatment conditions, with different morphologies and with a select mutant strain with deficiencies in the sterol uptake and biosynthesis pathway. We conclude that azole drugs are specifically selected and imported into the fungal cell by a pH- and ATP-independent facilitated diffusion mechanism, not by passive diffusion. This method of drug transport is likely to be conserved across most fungal species.