bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Plate Discretization on Accuracy of the Sound Radiation Efficiency Measurements
Authors: Kolber Karolina , Snakowska Anna , Kozupa Michał 
Published: April 2015

Abstract
This paper deals with the problem of the effect of discretization level and certain other parameters characterizing the measurement setup on accuracy of the process of determination of the sound radiation efficiency by means of the Discrete Calculation Method (DCM) described by Hashimoto (2001).
The idea behind DCM consists in virtual division of an examined sound radiating structure into rectangular elements each of which is further assumed to contribute to the total radiation effect in the same way as a rigid circular piston having the surface area equal to this of the corresponding virtual element and vibrating in an infinite rigid baffle. The advantage of the method over conventional sound radiation efficiency measurement techniques consists in the fact that instead of acoustic pressure values, source (plate) vibration velocity amplitude values are measured in a selected number of regularly distributed points. In many cases, this allows to determine the sound radiation efficiency with sufficient accuracy, especially for the low frequency regime.
The key part of the paper is an analysis of the effect of discretization level (i.e. the choice of the number of points at which vibration amplitude measurements are to be taken with the use of accelerometers) on results obtained with the use of the method and their accuracy. The problem of determining an optimum level of discretization for given excitation frequency range is a very important issue as the labor intensity (time-consuming aspect) of the method is one of its main flaws. As far as the technical aspect of the method is concerned, two different geometrical configurations of the measurement setup were tested.
Acoustic System of Determining the Instantaneous Volume of the Blood Part of the Ventricular Assist Device POLVAD-EXT
Authors: Konieczny Grzegorz , Pustelny Tadeusz , Opilski Zbigniew , Gawlikowski Maciej 
Published: April 2015

Abstract
The paper presents the results of investigations concerning the noninvasive method of estimating the actual volume of the blood chamber of the POLVAD-EXT type ventricular assist device (VAD) during its operation. The proposed method is based on the principle of Helmholtz's acoustic resonance. Both the theory, main stages of the development of the measurement method as well as the practical implementation of the proposed method in the physical model of the POLVAD-EXT device are dealt with. The paper contains the results of static measurements by means of the proposed method (conducted at the Department of Optoelectronics, Silesian University of Technology) as well as the dynamic measurements taken at the Foundation of Cardiac Surgery Development (Zabrze, Poland) with the professional model of the human cardiovascular system. The results of these measurements prove that the proposed method allows to estimate the actual blood chamber volume with uncertainties below 10%.
Control of Bending-Bending Coupled Vibrations of a Rotating Thin-Walled Composite Beam
Authors: Latalski Jarosław , Bocheński Marcin , Warmiński Jerzy 
Published: April 2015

Abstract
The paper presents a study of a possible application of structure embedded piezoelectric actuators to enhance the performance of a rotating composite beam exhibiting the coupled flexural-flexural vibrations. The discussed transversal and lateral bending modal coupling results from the directional properties of the beam's laminate and ply stacking distribution. The mathematical model of the beam is based on an assumption of cross-sectional non-deformability and it incorporates a number of non-classical effects. The final 1-D governing equations of an active composite beam include both orthotropic properties of the laminate and transversely isotropic properties of piezoelectric layers. The system's control capabilities resulting from embedded Macro Fiber Composite piezoelectric actuators are represented by the boundary bending moment. To enhance the dynamic properties of the composite specimen under consideration a combination of linear proportional control strategies has been used. Comparison studies have been performed, including the impact on modal coupling magnitude and cross-over frequency shift.
Modal Analysis of a Trapezoidal Violin Built After the Description of Félix Savart
Authors: Duerinck Tim , Skrodzka Ewa , Linde Bogumił B.J. 
Published: April 2015

Abstract
One-dimensional experimental modal analysis of an unvarnished trapezoidal violin built after the description of F. Savart and an anonymous trapezoidal violin on display in the Music Instrument Museum of Brussels is described. The analysis has revealed ten prominent modes. A mode that may potentially play a role of the “tonal barometer” of the instrument is pointed out. The mode shapes are symmetric and of high amplitude, due to the construction of the instrument. Subjective evaluation of the sound quality demonstrated no pronounced difference between the trapezoidal violin and normal violin.
Classification of Music Genres Based on Music Separation into Harmonic and Drum Components
Authors: Rosner Aldona , Schuller Bjӧrn , Kostek Bozena 
Published: April 2015

Abstract
This article presents a study on music genre classification based on music separation into harmonic and drum components. For this purpose, audio signal separation is executed to extend the overall vector of parameters by new descriptors extracted from harmonic and/or drum music content. The study is performed using the ISMIS database of music files represented by vectors of parameters containing music features. The Support Vector Machine (SVM) classifier and co-training method adapted for the standard SVM are involved in genre classification. Also, some additional experiments are performed using reduced feature vectors, which improved the overall result. Finally, results and conclusions drawn from the study are presented, and suggestions for further work are outlined.
Identification of the Types of Measured Acoustic Modes Inside the Operator's Cab in a Bulldozer
Authors: Dziechciowski Zygmunt , Kozień Marek S. 
Published: April 2015

Abstract
The aim of the study was to identify acoustic and structural modes in the spectrum obtained exper-imentally inside an operator's cab in a bulldozer. Measurements were taken inside the operator's cab in a caterpillar-track bulldozer Polremaco TD12NPH2E-2000, designed for work in underground mine enclosures. The acoustic pressure spectrum was obtained for varied rotational speeds of the engine during the free run of the machine. The reverberation time of the cab was determined basing on the pulse-type excited pressure response, followed by identification of the spectral components registered by measurements. Thus, identified frequencies were compared with natural acoustic frequencies registered inside the operator's cab and with frequencies associated with the valves and ignition frequencies due to rotational speed and natural frequencies of structural vibrations of the cab's walls. This study was conducted in an attempt to reduce the noise inside the operator's cab using passive methods
Ionic Liquids as New Quenching Media for Aluminium Alloys and Steels*
Authors: Beck M. , Schmidt C. , Ahrenberg M. , Schick C. , Kragl U. , Kessler O. 
Published: April 2015

Abstract

Quenching in vaporising liquids is mostly affected by the Leidenfrost effect, causing avoidable residual stresses and distortion. Molten salts and molten metals provide a quenching without any Leidenfrost effect, but need to be operated at high bath temperatures with a high effort for cleaning the quenched components. In this work ionic liquids (salts with melting temperatures below 100 °C) are investigated as quenching media with respect to cooling power, homogeneity and thermal stability. Aluminium and steel cylinders have been quenched in baths of different ionic liquids with varying compositions and bath temperatures showing almost no Leidenfrost effect. The time-temperature curves have been recorded and the heat transfer coefficients were determined. It was shown, that the cooling power of ionic liquids could be increased by limited water addition without any Leidenfrost effect and is sufficiently fast even for quench sensitive alloys. Further investigations on aluminium samples with a complex profile show that quenching in ionic liquids causes less distortion compared to water quenching.
Structural, thermal and optical studies of nanocomposite powder NiSb + Sb produced by mechanical alloying
Authors: de Souza Sérgio Michielon , da Silva Gleison Adriano , Lima Cláudio Natálio , Trichês Daniela Menegon , Poffo Cláudio Michel , de Lima João Cardoso 
Published: April 2015

AbstractA nanostructured composite powder formed from 75 wt.% NiSb and 25 wt.% Sb was obtained by mechanical alloying binary mixtures of elemental Ni and Sb powders in the composition NiSb2for 39 hours. The structural evolution was followed by X-ray diffraction measurements and Rietveld structural refinement. At the end of milling, the crystallites of Sb and NiSb reached a mean size of 17 and 15 nm, respectively. Differential scanning calorimetry measurement showed two exothermic processes at 263 °C and 309 °C. Variable temperature powder X-ray diffraction measurements at 25, 100, 200 and 300 °C showed that the sample is structurally stable until 100 °C. The beginning of the transition NiSb + Sb → NiSb2was observed at 200 °C and the nucleation of Sb2O3was observed at 300 °C in accordance with differential scanning calorimetry measurement. Raman spectroscopy measurements showed neither NiSb nor NiSb2compounds produce significant Raman signals when compared with Sb and Sb2O3.
Heat Treatment-Induced Improvement of the Thermal Shock Resistance of Si3N4 Tools for Metallurgical Applications
Authors: Harrer W. , Danzer R. , Berroth K. 
Published: April 2015

Abstract
Owing to its excellent mechanical and thermal properties, silicon nitride is an increasingly used tool material in the metallurgical industry. Some of its applications involve high thermal cycling loads, which may lead to tool failure. The failure of ceramic materials initiates from defects in the volume or on the surface of components and samples. Surface defects, often introduced during finishing, are considerably more harmful than defects in the volume. It was possible to heal surface defects by applying a specifically developed heat treatment – provided the defects are not too large.
In water quenching experiments on samples and components, it could be proven that the strength increase induced by the heat treatment also results in an improved thermal shock resistance. Due to high processing costs and in some cases due to the components' geometry, enhancing the surface quality of components is not possible. The proposed heat treatment is an alternative to increase strength, thermal shock resistance (and thus the reliability and service life of silicon nitride components) which requires little effort.
Tidally driven ice speed variation at Helheim Glacier, Greenland, observed with terrestrial radar interferometry
Authors: Voytenko Denis , Stern Alon , Holland David M. , Dixon Timothy H. , Christianson Knut , Walker Ryan T. 
Published: April 2015

AbstractWe used a terrestrial radar interferometer (TRI) at Helheim Glacier, Greenland, in August 2013, to study the effects of tidal forcing on the terminal zone of this tidewater glacier. During our study period, the glacier velocity was up to 25 m d–1. Our measurements show that the glacier moves out of phase with the semi-diurnal tides and the densely packed melange in the fjord. Here detrended glacier displacement lags behind the forecasted tidal height by ∼8 hours. The transition in phase lag between the glacier and the melange happens within a narrow (∼500 m) zone in the fjord in front of the ice cliff. The TRI data also suggest that the impact of tidal forcing decreases rapidly up-glacier of the terminus. A flowline model suggests this pattern of velocity perturbation is consistent with weak ice flowing over a weakly nonlinear bed.
Low Levels of Serum Uric Acid Increase the Risk of Low Bone Mineral Density in Young Male Patients with Ankylosing Spondylitis
Authors: Kang Kwi Young , Hong Yeon Sik , Park Sung-Hwan , Ju Ji Hyeon 
Published: April 2015

Objective.Uric acid (UA) has antiosteoporotic effects in postmenopausal women. This study investigated the association between serum UA levels and bone mineral density (BMD) in young male patients with ankylosing spondylitis (AS).Methods.One hundred fifty patients who fulfilled the modified New York criteria for the classification of AS were analyzed. All patients were male and under 50 years of age. BMD, serum UA concentrations, clinical variables, and radiographic progression were assessed. The associations between UA and BMD at the lumbar spine and hip were evaluated using multiple linear regression analysis. Multivariate logistic regression analyses were performed to identify risk factors associated with low BMD.Results.Mean serum UA concentration in the 150 patients with AS was 5.5 ± 1.3 mg/dl. BMD at the lumbar spine, but not at the total hip and femoral neck, increased with increasing serum UA tertiles (p = 0.033). The significant positive association between serum UA and BMD at the lumbar spine remained after adjustment for confounding factors (β = 0.185, p = 0.014, adjusted R2= 0.310). Multiple logistic regression analyses showed that lower UA concentrations (OR 4.02, 95% CI 1.34–12.3) and body mass index and increased erythrocyte sedimentation rate were independently associated with the risk of low BMD.Conclusion.Lower serum UA levels are associated with lower BMD in young male patients with AS. UA may be a novel predictive marker or therapeutic target in patients with AS.
Predictors of Longterm Changes in Body Mass Index in Rheumatoid Arthritis
Authors: Baker Joshua F. , Cannon Grant W. , Ibrahim Said , Haroldsen Candace , Caplan Liron , Mikuls Ted R. 
Published: April 2015

Objective.Low body mass index (BMI) is a risk factor for poor longterm outcomes in rheumatoid arthritis (RA). The purpose of this study was to identify factors associated with longterm changes in BMI.Methods.Subjects with RA from the Veterans Affairs (VA) Rheumatoid Arthritis (VARA) Registry (n = 1474) were studied. Information on inflammatory markers, presence of erosions, and smoking status were extracted from the VARA database. BMI was extracted from VA electronic medical records within 14 days of each visit date. VA pharmacy records were queried to identify prescriptions for specific RA therapies within 1 month of the visit date. We used robust generalized estimating equations marginal regression models to calculate independent associations between clinical variables and BMI over time. Similar models determined predictors of change in weight and risk of weight loss over the subsequent study observation period.Results.Increasing age, active smoking, and the presence of erosions at baseline were associated with lower BMI. Weight decreased over time among older adults. Factors associated with greater reductions in BMI over time and a greater risk of weight loss were higher inflammatory markers, smoking, older age, higher BMI, and less subsequent improvement in inflammation. Methotrexate use was associated with a lower risk of weight loss. The use of prednisone or anti-tumor necrosis factor therapies was not associated with change in BMI or the risk of weight loss independent of other factors.Conclusion.Greater age, greater inflammatory activity, and active smoking are associated with greater weight loss in RA over time.
La politique (tout) contre le Marché ?
Authors: Vauchez Antoine 
Published: April 2015

Qui douterait encore aujourd’hui de l’existence, à l’échelon européen, d’un véritable centre de pouvoir auquel les États ne cessent du reste de déléguer de nouvelles responsabilités ? Est-il pour autant un espace politique comme les autres, justiciable des mots et syntagmes par lesquels on saisit ordinairement la politique nationale des partis et des institutions politiques ? On pourrait à première vue le penser, si l’on en juge au fait que les traités et les autres textes normatifs ont au fil des années jonché le sol européen de tous les « gros mots » de la démocratie représentative. Si l’on parle bien désormais, à l’échelon européen, d’élections, de « partis politiques », de « Parlement », d’« investiture », d’« espace public », voire de « société civile », pourquoi n’y aurait-il pas là le cadre d’une « démocratie représentative », comme il en existe en France, en Allemagne ou en Grande-Bretagne ?
The impact of high‐density spatial sampling versus antenna orientation on 3D GPR fracture imaging
Authors: Pierpaolo Marchesini , Mark Grasmueck 
Published: April 2015

ABSTRACTThree‐dimensional Ground Penetrating Radar (3D GPR) surveys are necessary to reconstruct complex fracture geometries in the subsurface. Two of the most important factors controlling image quality are antenna orientation relative to fractures and density of acquisition grids. This study, conducted in the Madonna della Mazza quarry (Italy), compares two acquisition methods with the goal of optimizing the imaging of fractures and related 3D fracture networks. We acquired two very dense, orthogonal 3D GPR surveys with a 250 MHz antenna and 5 cm trace spacing on the same day, covering the same area of 20 × 20 m. By decimation of the original raw datasets, reduced survey densities of 10 cm and 20 cm spacing are simulated. The results show differences in the imaging quality of the two methods to depths of 75 cm, while for a depth of 130 cm and deeper, image quality is similar. At the same trace density/m2, a single, unidirectional survey with a densely sampled grid is the preferred method rather than two surveys with orthogonal antenna orientations but larger profile spacing. The extra effort of conducting surveys with an acquisition grid of an eighth of wavelength of the antenna centre frequency guarantees that we can properly sample the high‐frequency content of the GPR signal spectrum and results in optimum image quality regardless of fracture orientation. The simple survey design principle found in this study is universally applicable to any field condition, target geometry, and antenna frequency. Such high‐density 3D GPR survey design enables the high‐resolution characterization of 3D fracture networks on subsurface timeslices in near photographic quality.
Prognostic Value of Initial Elevation in Cardiac Troponin I Level in Critically Ill Patients Without Acute Coronary Syndrome
Authors: Liu Michael , Shehu Merita , Herrold Edmund , Cohen Henry 
Published: April 2015

BackgroundCardiac troponin I levels are often obtained to help rule out acute coronary syndrome.ObjectiveTo determine if elevation of troponin level within 24 hours for patients without acute coronary syndrome admitted to the intensive care unit provides important prognostic information. METHODS Patients without acute coronary syndrome admitted to the intensive care unit were prospectively divided into 2 groups according to highest serum level of cardiac troponin I within 24 hours of admission (elevated &gt; 0.049 ng/mL; control ≤ 0.049 ng/mL). Hospital mortality, incidence of intubation, and other parameters were compared between the 2 groups.ResultsPatients with elevated troponin level (n = 40) had higher mortality than did control patients (n = 50) (35% vs 12%; P = .01). Compared with control patients, patients with elevated levels were more likely to be intubated (41% vs 17%; P = .02).ConclusionCritically ill patients without acute coronary syndrome with elevated levels of cardiac troponin I at admission had higher mortality and more intubations than did control patients.
Validity and Feasibility of the Minicard Direct Observation Tool in 1 Training Program
Authors: Donato Anthony A. , Park Yoon Soo , George David L. , Schwartz Alan , Yudkowsky Rachel 
Published: April 2015

Abstract

Background
Availability of reliable, valid, and feasible workplace-based assessment (WBA) tools is important to allow faculty to make important and complex judgments about resident competence. The Minicard is a WBA direct observation tool designed to provide formative feedback while supporting critical competency decisions.

Objective
The purpose of this study was to collect validity and feasibility evidence for use of the Minicard for formative assessment of internal medicine residents.

Methods
We conducted a retrospective cohort analysis of Minicard observations from 2005–2011 in 1 institution to obtain validity evidence, including content (settings, observation rates, independent raters); response process (rating distributions across the scale and ratings by month in the program); consequences (qualitative assessment of action plans); and feasibility (time to collect observations).

Results
Eighty faculty observers recorded 3715 observations of 73 residents in the inpatient ward (43%), clinic (39%), intensive care (15%), and emergency department (3%) settings. Internal medicine residents averaged 28 (SD = 8.4) observations per year from 9 (SD = 4.1) independent observers. Minicards had an average of 5 (SD = 5.1) discrete recorded observations per card. Rating distributions covered the entire rating scale, and increased significantly over the time in training. Half of the observations included action plans with action-oriented feedback, 11% had observational feedback, 9% had minimal feedback, and 30% had no recorded plan. Observations averaged 15.6 (SD = 9.5) minutes.

Conclusions
Validity evidence for the Minicard direct observation tool demonstrates its ability to facilitate identification of “struggling” residents and provide feedback, supporting its use for the formative assessment of internal medicine residents.
An Analysis of the Potential Use of Public-Private Partnerships in Water Infrastructural Development in Zimbabwe: The Case of Harare City Council
Authors: Mutandwa Hudson , Zinyama Tawanda 
Published: April 2015

The study was carried out to analyse the potential use of Public Private Partnerships (PPPs) in water infrastructural development in Harare City Council, Zimbabwe. PPPs play a pivotal role in water infrastructural development if fully implemented. Zimbabwe’s rate of uptake is low. There are preconditions that are necessary for successful implementation of PPPs inter alia political will (commitment) legal, institutional and political frameworks. Key informant interviews and documentary search were employed to gather data. The study established that Zimbabwe does not have the preconditions necessary for successful implementation of PPPs and this confirms the thesis. The main challenges include lack of legal and institutional framework, lack of political will, unconducive socio-economic environment. Zimbabwe’s water infrastructure is ramshackle. This is compounded by lack of fiscal space on the part of government to rehabilitate the infrastructure. PPPs could be a viable alternative to infrastructural development with the right environmental conditions. The study recommends that the government should quickly enact a PPP legal framework that enables the establishment of a PPP unit within the Ministry of Finance and this should be followed by an Act of Parliament which should institutionalize PPPs. The Government should promote a conducive investment climate.