bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combination Axial and Radial Active Magnetic Bearing With Improved Axial Bandwidth
Authors: Filatov Alexei V. , Hawkins Lawrence A. 
Published: December 2013

Homopolar Permanent-Magnet-Biased Combination Axial and Radial Electromagnetic Actuators used in Active Magnetic Bearings (AMBs) have several advantages over arrangements of separate axial and radial actuators including shorter length, lower part count, lower cost and better rotordynamic response. However, these actuators may require higher-order compensators in applications with significant dynamic axial loads due to somewhat lower axial bandwidth.
One of the reasons for a lower axial bandwidth is having the axial magnetic control flux flowing through an opening in a radial actuator assembled from insulated electrical-steel laminations stacked axially. Whenever this flux changes in time, it induces an electrical current in each lamination which is responsible for the dynamic axial force reduction and an additional phase lag.
In an improved actuator design, a current path in each lamination is interrupted by a single slot located between two radial control poles. In order to maintain structural integrity of the stack and magnetic conductivity between the radial poles, the slot position is rotated by 90 degrees between each subsequent lamination in the stack.
The solution has been evaluated in a test actuator with 3000N axial and 1200N radial load capacities. 7dB gain improvement and 15 degrees phase improvement at 30Hz have been demonstrated.
Turbomachinery for Supercritical CO2 Power Cycles
Authors: Fuller Robert , Preuss Jason , Noall Jeff 
Published: December 2013

Supercritical CO2 (S-CO2) power cycles offer high plant efficiencies and beneficial economics for variety of heat sources. Nuclear, solar, waste heat, energy storage, and clean coal combustion are some of the applications under consideration for S-CO2 power production. Different types of cycles, topping and bottoming, have been conceptualized based on the heat source. These cycles have the possibility of being economically beneficial and competitive against incumbent steam cycles, primarily due to reduced material costs. Often the turbo-machinery capabilities are overlooked during the cycle design process, or are not well understood.
A method and guideline for turbo machinery selection is offered. Several examples are offered to give the S-CO2 cycle designer to judge the compatibility of the turbo-machinery with the overall system including type, size, and efficiency. The guideline includes turbo machinery design limitations. Understanding the turbo machinery implications relative to cycle design will allow the system designer to optimize the plant for efficiency and positive economic outcome.
Aerodynamic and Mechanical Optimization of CF/PEEK Blades of a Counter Rotating Fan
Authors: Goerke Daniel , Le Denmat Anne-Laure , Schmidt Thomas , Kocian Frank , Nicke Eberhard 
Published: December 2013

Since the development of the CRISP [1–3], a counter rotating integrated shrouded propfan, within a MTU-DLR program between 1985 and 2000, huge improvements in fan technologies have been made. In 2010 DLR launched an initiative to redesign the existing fan blades, taking advantage the latest developments in the field of material and manufacturing technology as well as numerical methods.
The new fan blades will be made of a carbon fiber reinforced PEEK material. Compared to the so called “onion skin configuration” of CRISP-1m, the layers of the CRISP2 lamina setups are parallel to each other. In contrast to metals, carbon fiber reinforced plastics have an orthotropic material behavior and a higher stiffness mass ratio, which have to be taken into account. The existing shaft and bearing system of the CRISP-1m-model [1–3] will be reused. The blades are mounted in titanium clevises by bolting.
To achieve an optimal design, it is necessary to optimize the aerodynamic performance together with the mechanical behavior within a multidisciplinary automated optimization process.
The optimization featured approximately one hundred free design variables, two objective functions (maximal displacement for respectively Rotor 1 and Rotor 2), as well as a high number of aerodynamic and mechanical constraints (efficiency, total pressure ratio, axial Mach number, stress, strain, eigenfrequencies, etc.).
This work shows how the challenge to integrate the modeling of CF/PEEK blades in a multidisciplinary design process were met in terms of the methods and optimization strategies involved. The major results of this optimization will be presented.
This design approach will give a new CRISP blade design ready for a planned rig test in the axial compressor test rig at the DLR in Cologne.
Housing Stiffness Influence on Gearbox Dynamic Loading for Wind Turbine Applications
Authors: Jauregui Juan Carlos , Torres Ignacio , Garcia Ricardo , Leon Alejandro 
Published: December 2013

The design of wind turbine gearboxes must consider particular conditions such as wind speed variations, load changes, and they must be as light as possible. Although there are enough field data, their life prediction lacks of good estimation. It is common to find gearboxes with bearing or gear premature failures. The housing can dissipate noise and vibrations in a positive manner; but in wind turbines it can increase the synchronization among nonlinear elements. This phenomenon adds an additional dynamic load on the gears and rolling bearings.
The work presented here is a method for estimating the influence of the housing stiffness on the dynamic synchronization of wind turbine gearbox elements. The analysis estimates a dynamic load factor that affects both gears and rolling bearings. The analysis takes into account the gearbox nonlinear elements, as well as the turbine blades excitations.
Dynamic Effects Caused by the Non-Linear Behavior of Oil-Film Journal Bearings in Rotating Machines
Authors: Vania A. , Pennacchi P. , Chatterton S. 
Published: December 2013

Many common faults and malfunctions in rotating machines mainly cause synchronous vibrations (1X). Very high 1X vibration levels can occur, in case of severe faults. Large journal orbits inside oil-film journal bearings may generate non-linear effects in the oil-film forces, whose presence can be detected by means of the appearance of not negligible super-synchronous vibrations of the shafts.
In this paper, a model-based method has been used to study the effects of non-linear oil-film forces on the machine dynamic behavior that may occur during runups and rundowns.
In general, it is possible to suppose that the importance of the non-linear behavior of oil-film journal bearings, and then the level of the super-synchronous vibrations, increases with the amplitude of the 1X vibrations caused by the primary fault. However, the numerical results of this study and the experimental evidences found in the monitoring data of a real machine have shown that the super-synchronous harmonic components of the oil-film forces may excite resonances of the shaft-train causing unexpected amplifications of the super-synchronous vibrations. This may make difficult the recognition of the presence of non-linear effects in the machine dynamic behavior and the identification of the actual cause of abnormal vibrations.
Failure of Clindamycin To Eradicate Infection with Beta-Hemolytic Streptococci Inducibly Resistant to Clindamycin in an Animal Model and in Human Infections
Authors: Lewis James S. , Lepak Alex J. , Thompson George R. , Craig William A. , Andes David R. , Sabol-Dzintars Kathryn E. , Jorgensen James H. 
Published: December 2013

ABSTRACT

Inducible clindamycin resistance in beta-hemolytic streptococci remains an underrecognized phenomenon of unknown clinical significance. We performed an evaluation of inducible clindamycin resistance using an animal model as well as retrospectively reviewing the charts of patients treated with clindamycin monotherapy who were infected with beta-hemolytic streptococci inducibly resistant to clindamycin. The neutropenic mouse thigh model of infection was used to evaluate the
in vivo
activity of clindamycin against beta-hemolytic streptococci, including isolates susceptible, inducibly resistant, or constitutively resistant to clindamycin. The clinical microbiology laboratory information system and pharmacy databases were cross-referenced to identify patients with infections due to inducibly clindamycin-resistant beta-hemolytic streptococci who were treated with clindamycin monotherapy. Medical records of these patients were reviewed to evaluate microbiologic and clinical outcomes. Inducible clindamycin resistance resulted in impaired killing of beta-hemolytic streptococci in the animal model. Though suppressed initially, compared to those with constitutive resistance (
P
= 0.0429), by 48 h, colony counts of inducibly clindamycin-resistant organisms were similar to those of constitutively resistant isolates (
P
= 0.1142). In addition, we identified 8 patients infected with inducibly clindamycin-resistant beta-hemolytic streptococci who experienced clinical and microbiologic failure when treated with clindamycin monotherapy. These patients either improved initially and subsequently failed or never responded to clindamycin therapy. We have demonstrated in a murine model of infection and from human cases that inducible clindamycin resistance in beta-hemolytic streptococci is clinically significant. Routine testing and reporting by clinical laboratories should be encouraged and alternative antimicrobial agents considered when these organisms are encountered in clinical care.
Susceptibility of Multiresistant Gram-Negative Bacteria to Fosfomycin and Performance of Different Susceptibility Testing Methods
Authors: Perdigão-Neto L. V. , Oliveira M. S. , Rizek C. F. , Carrilho C. M. D. M. , Costa S. F. , Levin A. S. 
Published: December 2013

ABSTRACT

Fosfomycin may be a treatment option for multiresistant Gram-negative bacteria. This study compared susceptibility methods using 94 multiresistant clinical isolates. With agar dilution (AD), susceptibilities were 81%, 7%, 96%, and 100% (CLSI) and 0%, 0%, 96%, and 30% (EUCAST), respectively, for
Acinetobacter baumannii
,
Pseudomonas aeruginosa
,
Klebsiella pneumoniae
, and
Enterobacter
spp. Categorical agreement between Etest and AD for
Enterobacteriaceae
and
A. baumannii
was ≥80%. Disk diffusion was adequate only for
Enterobacter
. CLSI criteria for urine may be adequate for systemic infections.
Moxifloxacin Pharmacokinetics and Pleural Fluid Penetration in Patients with Pleural Effusion
Authors: Chatzika Kalliopi , Manika Katerina , Kontou Paschalina , Pitsiou Georgia , Papakosta Despina , Zarogoulidis Konstantinos , Kioumis Ioannis 
Published: December 2013

ABSTRACTThe aim of this study was to evaluate the pharmacokinetics and penetration of moxifloxacin (MXF) in patients with various types of pleural effusion. Twelve patients with empyema/parapneumonic effusion (PPE) and 12 patients with malignant pleural effusion were enrolled in the study. A single-dose pharmacokinetic study was performed after intravenous administration of 400 mg MXF. Serial plasma (PL) and pleural fluid (PF) samples were collected during a 24-h time interval after drug administration. The MXF concentration in PL and PF was determined by high-performance liquid chromatography, and main pharmacokinetic parameters were estimated. Penetration of MXF in PF was determined by the ratio of the area under the concentration-time curve from time zero to 24 h (AUC24) in PF (AUC24PF) to the AUC24in PL. No statistically significant differences in the pharmacokinetics in PL were observed between the two groups, despite the large interindividual variability in the volume of distribution, clearance, and elimination half-life. The maximum concentration in PF (CmaxPF) in patients with empyema/PPE was 2.23 ± 1.31 mg/liter, and it was detected 7.50 ± 2.39 h after the initiation of the infusion. In patients with malignant effusion, CmaxPFwas 2.96 ± 1.45 mg/liter, but it was observed significantly earlier, at 3.58 ± 1.38 h (P< 0.001). Both groups revealed similar values of AUC24PF(31.83 ± 23.52 versus 32.81 ± 12.66 mg · h/liter). Penetration of MXF into PF was similarly good in both patient groups (1.11 ± 0.74 versus 1.17 ± 0.39). Despite similar plasma pharmacokinetics, patients with empyema/parapneumonic effusion showed a significant delay in achievement of PF maximum MXF levels compared to those with malignant effusion. However, in both groups, the degree of MXF PF penetration and the on-site drug exposure, expressed by AUC24PF, did not differ according to the type of pleural effusion.
Two-Photon Intravital Imaging of Lungs during Anthrax Infection Reveals Long-Lasting Macrophage-Dendritic Cell Contacts
Authors: Fiole Daniel , Deman Pierre , Trescos Yannick , Mayol Jean-François , Mathieu Jacques , Vial Jean-Claude , Douady Julien , Tournier Jean-Nicolas 
Published: December 2013

ABSTRACT

The dynamics of the lung immune system at the microscopic level are largely unknown because of inefficient methods of restraining chest motion during image acquisition. In this study, we developed an improved intravital method for two-photon lung imaging uniquely based on
a posteriori
parenchymal tissue motion correction. We took advantage of the alveolar collagen pattern given by the second harmonic generation signal as a reference for frame registration. We describe here for the first time a detailed dynamic account of two major lung immune cell populations, alveolar macrophages and CD11b-positive dendritic cells, during homeostasis and infection by spores of
Bacillus anthracis
, the agent of anthrax. We show that after alveolar macrophages capture spores, CD11b-positive dendritic cells come in prolonged contact with infected macrophages. Dendritic cells are known to carry spores to the draining lymph nodes and elicit the immune response in pulmonary anthrax. The intimate and long-lasting contacts between these two lines of defense may therefore coordinate immune responses in the lung through an immunological synapse-like process.
Interleukin-17A Enhances Host Defense against Cryptococcal Lung Infection through Effects Mediated by Leukocyte Recruitment, Activation, and Gamma Interferon Production
Authors: Murdock Benjamin J. , Huffnagle Gary B. , Olszewski Michal A. , Osterholzer John J. 
Published: December 2013

ABSTRACT

Infection of C57BL/6 mice with the moderately virulent
Cryptococcus neoformans
strain 52D models the complex adaptive immune response observed in HIV-negative patients with persistent fungal lung infections. In this model, Th1 and Th2 responses evolve over time, yet the contribution of interleukin-17A (IL-17A) to antifungal host defense is unknown. In this study, we show that fungal lung infection promoted an increase in Th17 T cells that persisted to 8 weeks postinfection. Our comparison of fungal lung infection in wild-type mice and IL-17A-deficient mice (IL-17A
−/−
mice; C57BL/6 genetic background) demonstrated that late fungal clearance was impaired in the absence of IL-17A. This finding was associated with reduced intracellular containment of the organism within lung macrophages and deficits in the accumulation of total lung leukocytes, including specific reductions in CD11c
+
CD11b
+
myeloid cells (dendritic cells and exudate macrophages), B cells, and CD8
+
T cells, and a nonsignificant trend in the reduction of lung neutrophils. Although IL-17A did not alter the total number of CD4 T cells, decreases in the total number of CD4 T cells and CD8 T cells expressing gamma interferon (IFN-γ) were observed in IL-17A
−/−
mice. Lastly, expression of major histocompatibility complex class II (MHC-II) and the costimulatory molecules CD80 and CD86 on CD11c
+
CD11b
+
myeloid cells was diminished in IL-17A
−/−
mice. Collectively, these data indicate that IL-17A enhances host defenses against a moderately virulent strain of
C. neoformans
through effects on leukocyte recruitment, IFN-γ production by CD4 and CD8 T cells, and the activation of lung myeloid cells.
Creating a safe, reliable hospital at night handover: a case study in implementation science
Authors: McQuillan Annette , Carthey Jane , Catchpole Ken , McCulloch Peter , Ridout Deborah A , Goldman Allan P 
Published: December 2013

BackgroundWe developed protocols to handover patients from day to hospital at night (H@N) teams.SettingNHS paediatric specialist hospital.MethodWe observed four handover protocols (baseline, Phases 1, 2 and 3) over 2 years. A mixed-method study (observation, interviews, task analysis, prospective risk assessment, document and case note review) explored the impact of different protocols on performance.InterventionIn Phase 1, a handover protocol was introduced to resolve problems with the baseline H@N handover. Following this intervention, two further revisions to the handover occurred, driven by staff feedback (Phases 2 and 3).ResultsVariations in performance between handover protocols on three process measures, start time efficiency, total length of handover, and number of distractions and interruptions, were identified. Univariate regression analysis showed statistically significant differences between handover protocols on two surrogate outcome measures: number of flagging omissions and the number of out of hours deteriorations (p=0.04 for Phase 3 vs Phase 1 for both measures (CI 1.04 to 4.08; CI 1.03 to 4.33), and for Phase 3 vs Phase 2 (p=0.006 and p=0.001 (CI 1.22 to 5.15; CI 1.62 to 9.0)), respectively). The Phase 1 and 2 handover protocols were effective at identifying patients whose clinical condition warranted review overnight. Performance on both surrogate outcome measures, length of handover and distractions, deteriorated in Phase 3.ConclusionsA carefully designed prioritisation process within the H@N handover can be effective at flagging acutely unwell patients. However, the protocol we introduced was unsustainable. In a complex healthcare system, sustainable implementation of new processes may be threatened by conflicting goals.
Learning schema mappings
Authors: Cate Balder Ten , Dalmau Víctor , Kolaitis Phokion G. 
Published: December 2013

A schema mapping is a high-level specification of the relationship between a source schema and a target schema. Recently, a line of research has emerged that aims at deriving schema mappings automatically or semi-automatically with the help of data examples, that is, pairs consisting of a source instance and a target instance that depict, in some precise sense, the intended behavior of the schema mapping. Several different uses of data examples for deriving, refining, or illustrating a schema mapping have already been proposed and studied.
In this article, we use the lens of computational learning theory to systematically investigate the problem of obtaining algorithmically a schema mapping from data examples. Our aim is to leverage the rich body of work on learning theory in order to develop a framework for exploring the power and the limitations of the various algorithmic methods for obtaining schema mappings from data examples. We focus on GAV schema mappings, that is, schema mappings specified by GAV (Global-As-View) constraints. GAV constraints are the most basic and the most widely supported language for specifying schema mappings. We present an efficient algorithm for learning GAV schema mappings using Angluin's model of exact learning with membership and equivalence queries. This is optimal, since we show that neither membership queries nor equivalence queries suffice, unless the source schema consists of unary relations only. We also obtain results concerning the learnability of schema mappings in the context of Valiant's well-known PAC (Probably-Approximately-Correct) learning model, and concerning the learnability of restricted classes of GAV schema mappings. Finally, as a byproduct of our work, we show that there is no efficient algorithm for approximating the shortest GAV schema mapping fitting a given set of examples, unless the source schema consists of unary relations only.
Rigorous benchmarking in reasonable time
Authors: Kalibera Tomas , Jones Richard 
Published: December 2013

Experimental evaluation is key to systems research. Because modern systems are complex and non-deterministic, good experimental methodology demands that researchers account for uncertainty. To obtain valid results, they are expected to run many iterations of benchmarks, invoke virtual machines (VMs) several times, or even rebuild VM or benchmark binaries more than once. All this repetition costs time to complete experiments. Currently, many evaluations give up on sufficient repetition or rigorous statistical methods, or even run benchmarks only in training sizes. The results reported often lack proper variation estimates and, when a small difference between two systems is reported, some are simply unreliable.In contrast, we provide a statistically rigorous methodology for repetition and summarising results that makes efficient use of experimentation time. Time efficiency comes from two key observations. First, a given benchmark on a given platform is typically prone to much less non-determinism than the common worst-case of published corner-case studies. Second, repetition is most needed where most uncertainty arises (whether between builds, between executions or between iterations). We capture experimentation cost with a novel mathematical model, which we use to identify the number of repetitions at each level of an experiment necessary and sufficient to obtain a given level of precision.We present our methodology as a cookbook that guides researchers on the number of repetitions they should run to obtain reliable results. We also show how to present results with an effect size confidence interval. As an example, we show how to use our methodology to conduct throughput experiments with the DaCapo and SPEC CPU benchmarks on three recent platforms.
Adaptive scanning reduces sweep time for the Lisp2 mark-compact garbage collector
Authors: Morikawa Kazuya , Ugawa Tomoharu , Iwasaki Hideya 
Published: December 2013

Mark-compact garbage collection helps long-running programs avoid fragmentation. The Lisp2 mark-compact collector is a classic but still widely-used compaction algorithm. It sequentially scans the entire heap to compact all live objects at one end of the heap while preserving their order of addresses. Since the heap is generally large, this scanning takes a long time. Although some collectors adopt a separate bitmap into which mark bits of objects are stored to reduce the scanning time, we observed that scanning the bitmap can take longer than scanning the heap if objects are densely located. We propose a new scanning method from this observation, which adaptively alternates methods of scanning depending on heap usage; it scans those parts of the heap where live objects are densely located whereas it scans the bitmap for the remaining parts. We implemented this scanning method in the Lisp2 collector of Jikes RVM.
The experimental results revealed that the adaptive scanner scanned faster than the method that only scanned the heap and the method that only scanned the bitmap.