bluuebunny/crossref_metadata_2025 huggingface dataset:
Future Trends in Subsonic Transport Energy Efficient Turbofan Engines
Authors: Johnston R. P. , Ortiz P.
Published: April 2015

Details of the NASA sponsored General Electric Energy Efficient Engine (E3) technology program are presented along with a description of the engine, cycle and aircraft system benefits. Opportunities for further performance improvement beyond E3 are examined. Studies leading to the selection of the E3 cycle and configuration are summarized. The advanced technology features, cycle and component performance levels are also presented. An evaluation of the benefits of the fully developed Flight Propulsion System (FPS) is made relative to the NASA program goals by comparing the FPS with the CF6-50C where both are installed in advanced subsonic transport aircraft. Results indicate that a mission fuel saving from 15 to 23 percent is possible depending on mission length.
Simplifying the Development of Programs for Digital Engine Controllers
Authors: Rutherford D. A.
Published: April 2015

The paper describes a method of simplifying the preparation and development of control programs for microprocessor-based engine control systems. The system described employs a video display unit, VDU, connected to the digital controller. Programs are prepared in a simple high level language tailored to the requirements of engine control schemes. The paper also describes the internal software structure and features that are provided. An example of the procedures used to develop a simple control program illustrates how a user can concentrate on the control scheme rather than on software problems.
Joint Technology Demonstrator Engine: The Initial Test
Authors: Rohm B. N.
Published: April 2015

A general description of the Joint Technology Demonstration Engine (JTDE) is presented, and several aspects of the experimental test approach are addressed. Discussion of design performance details and test results are limited in scope because of the classified nature of this program.
An Investigation of Ingress for a Simple Shrouded Rotating Disc System With a Radial Outflow of Coolant
Authors: Owen J. M. , Phadke U. P.
Published: April 2015

A plane rotating disc and a plane stator with a cylindrical shroud are used to model the more complex geometry of an air-cooled gas turbine rotor. “Cooling” air, which is supplied to the center of the stator, leaves radially through the clearance between the rotating disc and a stationary shroud, and flow visualization and pressure measurements are used to determine the minimum dimensionless mass flow rate, Cw,min, of cooling air necessary to prevent the ingress of external fluid at the periphery of the system. From theoretical considerations, the results are correlated (for a gap ratio of G = 0.1, shroud clearance ratio between Gc = 0.0025 and Gc = 0.04, and rotational Reynolds numbers between Reθ = 2 × 105 and Reθ = 106) by Cw,min = cGcnReθ
Composition Structure of Burning Sprays of Jet a Fuel and its Emulsions With Water
Authors: Gollahalli S. R. , Javadi S. H.
Published: April 2015

This paper presents the axial and radial concentration profiles of various species (O2, N2, CO2, H2O, NO, NOx, and Cn Hm) in the burning sprays of Jet A fuel, its blend with 1 percent surfactant, and its emulsions with 1 percent surfactant and different water contents (5, 10, and 20 percent by volume). The composition structure of the flame studied is in conformity with the temperature, particulate concentration, and radiation profiles studied earlier. The results show that the increase of water content of emulsions decreases fuel pyrolysis and oxides of nitrogen, whereas the surfactant alone does not markedly affect the flame structure.
Temperature and Flow Measurements on Near-Freezing Aviation Fuels in a Wing-Tank Model
Authors: Friedman R. , Stockemer F. J.
Published: April 2015

Freezing behavior, pumpability, and temperature profiles for aviation turbine fuels were measured in a 190-liter tank, to simulate internal temperature gradients encountered in commercial airplane wing tanks. Two low-temperature situations were observed. Where the bulk of the fuel is above the specification freezing point, pumpout of the fuel removes all fuel except a layer adhering to the bottom chilled surfaces, and the unpumpable fraction depends on the fuel temperature near these surfaces. Where the bulk of the fuel is at or below the freezing point, pumpout ceases when solids block the pump inlet, and the unpumpable fraction depends on the overall average temperature.
Combustion Turbine Design Guidelines Based on Deposition/Corrosion Considerations
Authors: DeCorso S. M. , Vermes G. , Lee S. Y. , Singhal S. C. , Cohn A.
Published: April 2015

The objective of this project is to evolve design guidelines based on considerations of deposition and corrosion, for future operation of large stationary combustion turbines for electric power generation. The primary emphasis of the investigation is to establish the operating blade surface temperature, considering all aspects of deposition and corrosion, for a range of fuels including residual oil and coal-derived liquids. The design guidelines that will evolve from this program will provide a data base to determine the trade-offs between metal temperature, performance, maintenance and reliability. There is, at present, some operating and lab experience that indicates the possibility of serious deposition problems as turbine inlet temperature (TlT) increases, and as the differential between TlT and blade surface temperature increases. The concern regarding corrosion effects is centered on two considerations: a) Will metal surface temperature continue to govern the corrosion process as TlT increases, and b) Will present-day additives be effective at higher in-let temperatures and cycle pressures? Evaluation of the initial test results is presented.
A Review of Current Methods and Problems in Making Gas Path Measurements in Aircraft Gas Turbine Engines
Authors: Alwang W. G.
Published: April 2015

The gas path of an aircraft gas turbine engine presents some unique measurement problems. As part of the development of an engine, it is necessary to verify all of the critical design parameters such as air and metal temperature, dynamic and steady state stresses, pressure distributions and air flow in order to accurately interpret engine performance and endurance tests. Although a great deal can be accomplished within the current state-of-the-art, some very significant gaps remain in the needed measurement technology, particularly in the hottest sections of the engine. New sensors and measuring techniques are currently under development which promise to overcome many of the current problems.
Technical Note: On the proton range and nuclear interactions in compounds and mixtures
Authors: Rasouli Fatemeh S. , Masoudi S. Farhad , Jette David
Published: April 2015

Purpose:

Range and probability of nonelastic nuclear interactions (NNIs) for protons can be found only for a limited number of compounds and mixtures in nuclear data tables, and the proton‐related analytical studies are therefore restricted to those materials for which the data are provided in these documents. In this paper, the authors present general solutions for calculating the proton range and probability of NNIs for desired compounds and mixtures.

Methods:

Benefiting from the Bragg–Kleeman approximation of mass stopping power, the authors derive a concise formula for calculating the proton range in materials with arbitrary number of constituent elements. Additionally, the authors propose another relation for obtaining the probability of undergoing NNIs which is suggested to be additive.

Results:

The examination of the formula presented shows that the authors’ method can be considered as general solutions for analytical evaluation of the range in compounds and mixtures. The formula proposed for probability of NNIs is valid for almost every compound except for those materials containing H. It is shown that this formula can be modified so that it covers these materials.

Conclusions:

The authors present a general analytical method for calculating the range and probability of NNIs for protons which are mathematically easy to handle and valid for desired compounds or mixtures composed of an arbitrary number of constituent elements, including materials of interest for proton radiotherapy purposes.
Automated prostate cancer detection using T2‐weighted and high‐b‐value diffusion‐weighted magnetic resonance imaging
Authors: Kwak Jin Tae , Xu Sheng , Wood Bradford J. , Turkbey Baris , Choyke Peter L. , Pinto Peter A. , Wang Shijun , Summers Ronald M.
Published: April 2015

Purpose:

The authors propose a computer‐aided diagnosis (CAD) system for prostate cancer to aid in improving the accuracy, reproducibility, and standardization of multiparametric magnetic resonance imaging (MRI).

Methods:

The proposed system utilizes two MRI sequences [T2‐weighted MRI and high‐b‐value (b = 2000 s/mm2) diffusion‐weighted imaging (DWI)] and texture features based on local binary patterns. A three‐stage feature selection method is employed to provide the most discriminative features. The authors included a total of 244 patients. Training the CAD system on 108 patients (78 MR‐positive prostate cancers and 105 benign MR‐positive lesions), two validation studies were retrospectively performed on 136 patients (68 MR‐positive prostate cancers, 111 benign MR‐positive lesions, and 117 MR‐negative benign lesions).

Results:

In distinguishing cancer from MR‐positive benign lesions, an area under receiver operating characteristic curve (AUC) of 0.83 [95% confidence interval (CI): 0.76–0.89] was achieved. For cancer vs MR‐positive or MR‐negative benign lesions, the authors obtained an AUC of 0.89 AUC (95% CI: 0.84–0.93). The performance of the CAD system was not dependent on the specific regions of the prostate, e.g., a peripheral zone or transition zone. Moreover, the CAD system outperformed other combinations of MRI sequences: T2W MRI, high‐b‐value DWI, and the standard apparent diffusion coefficient (ADC) map of DWI.

Conclusions:

The novel CAD system is able to detect the discriminative texture features for cancer detection and localization and is a promising tool for improving the quality and efficiency of prostate cancer diagnosis.
Encouraging sanitation investment in the developing world: A cluster-randomized trial
Authors: Guiteras Raymond , Levinsohn James , Mobarak Ahmed Mushfiq
Published: April 2015

Helping the poor invest in sanitation

Almost a third of the world's people do not have access to hygienic latrines. Improving access to and increasing the use of latrines would reduce deaths and poor health caused by diarrheal disease. Guiteras
et al.
tested the relative benefits of supplying health information, offering a financial subsidy to purchasers of hygienic latrines, or increasing the availability of latrines for purchase. Providing the subsidy worked best: Nonsubsidized households were more likely to purchase latrines when other households in their village were subsidized.

Science
, this issue p.
903
Draft Genome Sequence of
Micrococcus
sp. Strain MS-AsIII-49, an Arsenate-Reducing Isolate from Tropical Metal-Rich Sediment
Authors: Costa Patrícia S. , Tschoeke Diogo A. , Silva Bruno S. O. , Thompson Fabiano , Reis Mariana P. , Chartone-Souza Edmar , Nascimento Andréa M. A.
Published: April 2015

Micrococcus
sp. strain MS-AsIII-49, which was isolated from a tropical metal-polluted stream sediment in Brazil, has the ability to reduce AsV to AsIII. Analysis of its draft genome revealed 186 contigs with a total size of 2,440,924 bp encoding several metal resistance genes.
Complete Genome Sequences of Two Helicobacter pylori Strains from a Canadian Arctic Aboriginal Community
Authors: Kersulyte Dangeruta , Bertoli M. Teresita , Tamma Sravya , Keelan Monika , Munday Rachel , Geary Janis , Veldhuyzen van Zanten Sander , Goodman Karen J. , Berg Douglas E.
Published: April 2015

We report here the complete genome sequences of two Amerind
Helicobacter pylori
strains from Aklavik, Northwest Territories, Canada. One strain contains extra iron-cofactored urease genes and ~140 rearrangements in its chromosome relative to other described strains (typically differing from one another by <10 rearrangements), suggesting that it represents a novel lineage of
H. pylori
.
Two Draft Genome Sequences of a New Serovar of Salmonella enterica, Serovar Lubbock
Authors: Bugarel Marie , den Bakker Henk C. , Nightingale Kendra K. , Brichta-Harhay Dayna M. , Edrington Thomas S. , Loneragan Guy H.
Published: April 2015

Salmonella enterica
is principally a foodborne pathogen that shows considerable serovar diversity. In this report, we present two draft genome sequences of
Salmonella enterica
subsp.
enterica
serovar Lubbock, a novel serovar.
Complete Genome Sequence of Mycoplasma arginini Strain HAZ 145_1 from Bovine Mastitic Milk in Japan
Authors: Hata Eiji
Published: April 2015

Mycoplasma arginini
is a species sometimes isolated from bovine specimens, mastitic milk, etc. Its pathogenicity against cows, however, is unspecific, unlike other bovine mycoplasmas. Its whole-genome sequence is needed to comprehend its real image. We present here the 678,592-bp complete genome sequence of
M. arginini
strain HAZ 145_1.
Draft Genome Sequence of an Anaerobic Ammonium-Oxidizing Bacterium, “
Candidatus
Brocadia sinica”
Authors: Oshiki Mamoru , Shinyako-Hata Kaori , Satoh Hisashi , Okabe Satoshi
Published: April 2015

A draft genome sequence of an anaerobic ammonium-oxidizing (anammox) bacterium, “
Candidatus
Brocadia sinica,” was determined by pyrosequencing and by screening a fosmid library. A 4.07-Mb genome sequence comprising 3 contigs was assembled, in which 3,912 gene-coding regions, 47 tRNAs, and a single
rrn
operon were annotated.
Draft Genome Sequence of Brevibacterium linens AE038-8, an Extremely Arsenic-Resistant Bacterium
Authors: Maizel Daniela , Utturkar Sagar M. , Brown Steven D. , Ferrero Marcela A. , Rosen Barry P.
Published: April 2015

To understand the arsenic biogeocycles in the groundwaters at Tucumán, Argentina, we isolated
Brevibacterium linens
sp. strain AE38-8, obtained from arsenic-contaminated well water. This strain is extremely resistant to arsenicals and has arsenic resistance (
ars
) genes in its genome. Here, we report the draft genome sequence of
B. linens
AE38-8.
Three-dimensional upper-bound analysis for ultimate bearing capacity of laterally loaded rigid pile in undrained clay
Authors: Yu Jian , Huang Maosong , Zhang Chenrong
Published: April 2015

A new three-dimensional upper-bound combined failure mechanism is presented to analyze the lateral ultimate capacity of rigid piles embedded in various soil conditions, involving homogeneous soils, layered soils, and Gibson soils. The wedge curved failure surface function composed by rotating the Newton interpolation polynomial is adopted near the ground surface, and a plane strain collapse mechanism is employed at depth. Furthermore, the energy dissipation of the transition interface is introduced to keep a kinematically admissible velocity field between the wedge and the plane strain mechanism. An empirical equation is then proposed based on the upper-bound solutions for the homogeneous soils, and extended to the layered soils and Gibson soils. Meanwhile, the three-dimensional arbitrary Lagrangian–Eulerian (ALE) analysis is employed to investigate the distribution of limiting pressures along the pile shaft for different soil parameters. It is found that the upper-bound solutions based on the rigid-plastic assumption only exhibits a good agreement with the finite element (FE) results for a very high soil rigidity index of 10 000, due to a Possion’s ratio of approximate but less than 0.5 in such a typical undrained FE analysis. For such a Possion’s ratio, an inevitably slight elastic volumetric change induces the unexpected cavity flow at the deep section of the pile. It leads to the soil rigidity affecting the profile distribution of the bearing capacity, although it is not true for a real undrained analysis. Finally, a centrifuge test is analyzed by the upper-bound method to further testify the rationality of the new failure mechanism.
Seismic soil–culvert interaction
Authors: Abuhajar Osama , El Naggar Hesham , Newson Tim
Published: April 2015

Box culverts may be constructed in active seismic areas, where ground shaking or ground failures can impose considerable earth pressures on them. In this study, the seismic response of box culverts was investigated experimentally and numerically. A series of scaled centrifuge tests was performed and subjected to three different earthquake signals, with different amplitudes and frequencies. Two values of culvert wall thickness and two values of sand relative density were considered in the experimental program. Experimental results are presented in terms of comparisons of seismic bending moments. These results were used to calibrate and verify two-dimensional numerical models developed using the computer program FLAC. The verified models were then used to investigate the effect of earthquake intensity and frequency, height of soil cover, and culvert thickness on the seismic bending moments for the different culvert sections. Based on the analysis results, charts are presented to aid in the seismic design of box culverts.
Identification and functional characterisation of a novel KCNJ2 mutation, Val302del, causing Andersen–Tawil syndrome
Authors: Ördög Balázs , Hategan Lidia , Kovács Mária , Seprényi György , Kohajda Zsófia , Nagy István , Hegedűs Zoltán , Környei László , Jost Norbert , Katona Márta , Szekeres Miklós , Forster Tamás , Papp Julius Gy. , Varró András , Sepp Róbert
Published: April 2015

Loss-of-function mutations of the KCNJ2 gene encoding for the inward rectifier potassium channel subunit Kir2.1 cause Andersen–Tawil Syndrome (ATS), a rare genetic disorder characterised by periodic paralysis, ventricular arrhythmias, and dysmorphic features. Clinical manifestations of the disease appear to vary greatly with the nature of mutation, therefore, functional characterisation of ATS-causing mutations is of clinical importance. In this study, we describe the identification and functional analysis of a novel KCNJ2 mutation, Val302del, identified in a patient with ATS. Heterologously expressed wild type (WT) and Val302del mutant alleles showed similar subcellular distribution of the Kir2.1 protein with high intensity labelling from the membrane region, demonstrating normal membrane trafficking of the Val302del Kir2.1 variant. Cells transfected with the WT allele displayed a robust current with strong inward rectification, while no current above background was detected in cells expressing the Val302del Kir2.1 subunit. Co-transfection of CHO cells with the WT and the Val302del Kir2.1 revealed a dose-dependent inhibitory effect of the Val302del Kir2.1 mutant subunit on WT Kir2.1 currents. These observations indicate that the WT and the Val302del mutant subunits co-assemble in the cell membrane and that the mutation affects potassium conductivity and (or) gating of the WT/Val302del heteromeric Kir2.1 channels.
Searching for radiative neutrino mass generation at the LHC
Authors: Volkas Raymond R.
Published: April 2015

In this talk (talk given at the International Conference on Massive Neutrinos, Singapore, 9-13 February 2015), I describe the general characteristics of radiative neutrino mass models that can be probed at the LHC. I then cover the specific constraints on a new, explicit model of this type.
The optimal decay estimates on the framework of Besov spaces for the Euler–Poisson two-fluid system
Authors: Xu Jiang , Kawashima Shuichi
Published: April 2015

In this paper, we are concerned with the optimal decay estimates for the Euler–Poisson two-fluid system. It is first revealed that the irrotationality of the coupled electronic field plays a key role such that the two-fluid system has the same dissipative structure as generally hyperbolic systems satisfying the Shizuta–Kawashima condition. This fact inspires us to obtain decay properties for linearized systems in the framework of Besov spaces. Furthermore, various decay estimates of solution and its derivatives of fractional order are deduced by time-weighted energy approaches in terms of low-frequency and high-frequency decompositions. As the direct consequence, the optimal decay rates of Lp(ℝ3)-L2 (ℝ3) (1 ≤ p < 2) type for the Euler–Poisson two-fluid system are also shown. Compared with previous works in Sobolev spaces, a new observation is that the difference of variables exactly consists of a one-fluid Euler–Poisson equations, which leads to the sharp decay estimates for velocities.
State sum construction of two-dimensional topological quantum field theories on spin surfaces
Authors: Novak S. , Runkel I.
Published: April 2015

We provide a combinatorial model for spin surfaces. Given a triangulation of an oriented surface, a spin structure is encoded by assigning to each triangle a preferred edge, and to each edge an orientation and a sign, subject to certain admissibility conditions. The behavior of this data under Pachner moves is then used to define a state sum topological field theory on spin surfaces. The algebraic data is a Δ-separable Frobenius algebra whose Nakayama automorphism is an involution. We find that a simple extra condition on the algebra guarantees that the amplitude is zero unless the combinatorial data satisfies the admissibility condition required for the reconstruction of the spin structure.
Flexural Vibration of an Atomic Force Microscope Cantilever Based on Modified Couple Stress Theory
Authors: Liang Li-Na , Ke Liao-Liang , Wang Yue-Sheng , Yang Jie , Kitipornchai Sritawat
Published: April 2015

This paper is concerned with the flexural vibration of an atomic force microscope (AFM) cantilever. The cantilever problem is formulated on the basis of the modified couple stress theory and the Timoshenko beam theory. The modified couple stress theory is a nonclassical continuum theory that includes one additional material parameter to describe the size effect. By using the Hamilton's principle, the governing equation of motion and the boundary conditions are derived for the AFM cantilevers. The equation is solved using the differential quadrature method for the natural frequencies and mode shapes. The effects of the sample surface contact stiffness, length scale parameter and location of the sensor tip on the flexural vibration characteristics of AFM cantilevers are discussed. Results show that the size effect on the frequency is significant when the thickness of the microcantilever has a similar value to the material length scale parameter.
Time Integration Method Based on Discrete Transfer Function
Authors: Rezaiee-Pajand M. , Hashemian M.
Published: April 2015

Complex structural dynamic problems are normally analyzed by finite element and numerical integration techniques. An explicit time integration algorithm with second-order accuracy and unconditional stability is presented for dynamic analysis. Utilizing weighted factors, the current displacement and velocity relations are defined in terms of the accelerations of two previous time steps. The concept of discrete transfer function and the pole mapping rule from the control theory are exploited to develop the new algorithm. Several linear and nonlinear dynamic analyses are performed to verify the efficiency of the method compared with the well-known Newmark method.
Building a Framework of Metadata Change to Support Knowledge Management
Authors: Zavalina Oksana L. , Kizhakkethil Priya , Alemneh Daniel Gelaw , Phillips Mark E. , Tarver Hannah
Published: April 2015

Evolving user needs and relevance require continuous change and reform. A good digital collection has mechanisms to accommodate the differing uses being made of the digital library system. In a metadata management context, change could mean to transform, substitute, or make the content of a metadata record different from what it is or from what it would be if left alone. In light of the evolving compliance requirements, this paper analyses the three most common types of change within metadata records as well as their subcategories and discusses the possible implications of such changes within and beyond the metadata records.
Construction of all cubic function fields of a given square-free discriminant
Authors: Jacobson M. J. , Lee Y. , Scheidler R. , Williams H. C.
Published: April 2015

For any square-free polynomial D over a finite field of characteristic at least 5, we present an algorithm for generating all cubic function fields of discriminant D. We also provide a count of all these fields according to their splitting at infinity. When D′ = D/(-3) has even degree and a leading coefficient that is a square, i.e. D′ is the discriminant of a real quadratic function field, this method makes use of the infrastructures of this field. This infrastructure method was first proposed by Shanks for cubic number fields in an unpublished manuscript from the late 1980s. While the mathematical ingredients of our construction are largely classical, our algorithm has the major computational advantage of finding very small minimal polynomials for the fields in question.
Solvothermal Synthesis of TiO2/CNFs Heterostructures with Photocatalytic Activity
Authors: Yu Dandan , Bai Jie , Gu Yulong , Li Chunping
Published: April 2015

Titanium dioxide nanoparticles ( TiO 2 NPs ) embedded carbon nanofibers (CNFs) have been successfully prepared by electrospinning technique, solvothermal synthesis and high-temperature calcination processes. The as-obtained products were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis diffuse reflectance spectra (DRS) and Fourier transform infrared (FTIR) spectra. The results of characterization revealed that solvothermal treatment and high-temperature calcination were beneficial to the synthesis of anatase TiO 2. Compared to the as-fabricated TiO 2 powder, TiO 2 NPs contained in the TiO 2/CNFs were successfully grown on the surface of CNFs without aggregation. The photocatalytic activities of the TiO 2/CNFs heterostructures were evaluated by the degradation of methyl orange (MO) under UV light irradiation for 14h. The TiO 2/CNFs exhibited higher photocatalytic activities than pure TiO 2 powder, which were attributed to the small size of TiO 2 NPs, electron transfer, high adsorption properties of CNFs and the formation of heterostructures between TiO 2 and CNFs. Moreover, in aqueous solution, the as-prepared TiO 2/CNFs could be easily recycled for the application of CNFs.
An Experimental Investigation on the Airside Performance of Fin-and-Tube Heat Exchangers Having Nonsymmetrical Slit Fins
Authors: Kim Nae-Hyun , Kwon Mi-Hye , Go Min-Geon
Published: April 2015

In this study, the heat transfer and friction characteristics of nonsymmetric slit-finned heat exchangers are experimentally investigated. Louver-finned heat exchangers are also tested for comparison purpose. The effect of fin pitch on j and f factors is negligible. Considering the small variation of the fin pitch (from 1.3 mm to 1.5 mm), the foregoing argument should hold true for the present samples. Louver fin samples yield higher j and f factors than slit fin samples. Both j and f factors increase as the number of tube rows decreases. The row effect is true for both slit and louver fin samples. For one-row configuration, j/f ratios of louver fin samples are larger than those of slit fin samples. The trend is, however, reversed for three-row configuration. Data are compared with available correlations.
Experimental and Numerical Investigations of the Double-Barrel Distributor for Air Conditioner
Authors: Zhang Chi , Wang Dandong , Chen Jiangping , Sun Xihui
Published: April 2015

Flow mal-distribution of refrigerant in small diameter tube heat exchangers is a great concern, which may lead to a 25% efficiency loss. Two-phase refrigerant distributors are set before evaporators to separate refrigerant into parallel paths uniformly. In this paper, a new type of distributor with two barrels is proposed. Experimental test and numerical simulation were both carried out to evaluate the performance and to understand internal hydrodynamic flow behavior. Compared with the previous distributor, it is found that the double-barrel distributor with proper parameters performs better. The relative error between experimental and simulation results is less than 15%, which proves the reliability of the established simulation model. Computation fluid dynamics (CFD) calculation indicates that the distribution performance is improved with properly larger bottom and top barrel diameters. With the increase of the bottom barrel diameter, beneficial reflux of refrigerant occurs in bottom barrel and when top barrel diameter is larger, little refrigerant flows directly into outlet capillary tubes without mixture or reflux. In addition, parameters such as top barrel diameter, top barrel height, bottom barrel diameter, bottom barrel height, mass flow rate and quality are studied by Taguchi Method to analyze the parameter sensitivity. The effect of the parameters listed below ranges from biggest to smallest: mass flow rate, bottom barrel height, quality, top barrel height, bottom barrel diameter and independent top barrel diameter. An optimized two-barrel distributor is achieved with proper top and bottom barrel diameters and larger bottom and top barrel heights.
Classification Framework of MapReduce Scheduling Algorithms
Authors: Tiwari Nidhi , Sarkar Santonu , Bellur Umesh , Indrawan Maria
Published: April 2015

A MapReduce scheduling algorithm plays a critical role in managing large clusters of hardware nodes and meeting multiple quality requirements by controlling the order and distribution of users, jobs, and tasks execution. A comprehensive and structured survey of the scheduling algorithms proposed so far is presented here using a novel multidimensional classification framework. These dimensions are (i) meeting quality requirements, (ii) scheduling entities, and (iii) adapting to dynamic environments; each dimension has its own taxonomy. An empirical evaluation framework for these algorithms is recommended. This survey identifies various open issues and directions for future research.
AIR
Authors: Wang Jingjing , Abu-Ghazaleh Nael , Ponomarev Dmitry
Published: April 2015

Parallel discrete event simulation (PDES) harnesses parallel processing to improve the performance and capacity of simulation, supporting bigger and more detailed models simulated for more scenarios. The presence of interference from other users can lead to dramatic slowdown in the performance of the simulation. Interference is typically managed using operating system scheduling support (e.g., gang scheduling), a heavyweight approach with some drawbacks. We propose an application-level approach to interference resilience through alternative simulation scheduling and mapping algorithms. More precisely, the most resilient simulators allow dynamic mapping of simulation event execution to processing resources (a work pool model). However, this model has significant scheduling overhead and poor cache locality. Thus, we investigate using application-level interference mitigation where the application detects the presence of interference and reacts by changing the thread task allocation. Specifically, we propose a locality-aware adaptive dynamic mapping (LADM) algorithm that adjusts the number of active threads on the fly by detecting the presence of interference. LADM avoids having the application stall when threads are inactive due to context switching. We investigate different mechanisms for monitoring the level of interference and different approaches for remapping tasks. We show that LADM can substantially reduce the impact of interference while maintaining memory locality.
Overlapping Batches for the Assessment of Solution Quality in Stochastic Programs
Authors: Love David , Bayraksan Güzin
Published: April 2015

Overlapping Batch Means (OBM) has long been used in simulation as a method of reusing data to generate variance estimators with asymptotically lower variance. In this article, we apply the OBM method to stochastic programming by formulating a variant of the multiple replications procedure used for assessing solution quality. We give conditions under which the resulting optimality gap point estimators are strongly consistent, the optimality gap interval estimators are asymptotically valid, and the OBM variance estimators for optimality gap have asymptotically lower variances relative to their nonoverlapping counterparts [Meketon and Schmeiser 1984; Welch 1987]. We investigate computational efficiency, a combined measure of variance and computation time, providing guidelines on the degree of overlap. Numerical experiments on several test problems are presented, examining the small-sample behavior and the empirical computational efficiency of the overlapping batches method in this context.
A Tutorial on Multilabel Learning
Authors: Gibaja Eva , Ventura Sebastián
Published: April 2015

Multilabel learning has become a relevant learning paradigm in the past years due to the increasing number of fields where it can be applied and also to the emerging number of techniques that are being developed. This article presents an up-to-date tutorial about multilabel learning that introduces the paradigm and describes the main contributions developed. Evaluation measures, fields of application, trending topics, and resources are also presented.
CERE
Authors: Castro Pablo De Oliveira , Akel Chadi , Petit Eric , Popov Mihail , Jalby William
Published: April 2015

This article presents Codelet Extractor and REplayer (CERE), an open-source framework for code isolation. CERE finds and extracts the hotspots of an application as isolated fragments of code, called
codelets
. Codelets can be modified, compiled, run, and measured independently from the original application. Code isolation reduces benchmarking cost and allows piecewise optimization of an application. Unlike previous approaches, CERE isolates codes at the compiler Intermediate Representation (IR) level. Therefore CERE is language agnostic and supports many input languages such as C, C++, Fortran, and D. CERE automatically detects codelets invocations that have the same performance behavior. Then, it selects a reduced set of representative codelets and invocations, much faster to replay, which still captures accurately the original application. In addition, CERE supports recompiling and retargeting the extracted codelets. Therefore, CERE can be used for cross-architecture performance prediction or piecewise code optimization. On the SPEC 2006 FP benchmarks, CERE codelets cover 90.9% and accurately replay 66.3% of the execution time. We use CERE codelets in a realistic study to evaluate three different architectures on the NAS benchmarks. CERE accurately estimates each architecture performance and is 7.3 × to 46.6 × cheaper than running the full benchmark.
Teaching Recommender Systems at Large Scale
Authors: Konstan Joseph A. , Walker J. D. , Brooks D. Christopher , Brown Keith , Ekstrand Michael D.
Published: April 2015

In the fall of 2013, we offered an open online Introduction to Recommender Systems through Coursera, while simultaneously offering a for-credit version of the course on-campus using the Coursera platform and a flipped classroom instruction model. As the goal of offering this course was to experiment with this type of instruction, we performed extensive evaluation including surveys of demographics, self-assessed skills, and learning intent; we also designed a knowledge-assessment tool specifically for the subject matter in this course, administering it before and after the course to measure learning, and again 5 months later to measure retention. We also tracked students through the course, including separating out students enrolled for credit from those enrolled only for the free, open course.

Students had significant knowledge gains across all levels of prior knowledge and across all demographic categories. The main predictor of knowledge gain was effort expended in the course. Students also had significant knowledge retention after the course. Both of these results are limited to the sample of students who chose to complete our knowledge tests. Student completion of the course was hard to predict, with few factors contributing predictive power; the main predictor of completion was intent to complete. Students who chose a concepts-only track with hand exercises achieved the same level of knowledge of recommender systems concepts as those who chose a programming track and its added assignments, though the programming students gained additional programming knowledge. Based on the limited data we were able to gather, face-to-face students performed as well as the online-only students or better; they preferred this format to traditional lecture for reasons ranging from pure convenience to the desire to watch videos at a different pace (slower for English language learners; faster for some native English speakers). This article also includes our qualitative observations, lessons learned, and future directions.
Human Norovirus as a Foodborne Pathogen: Challenges and Developments
Authors: Moore Matthew D. , Goulter Rebecca M. , Jaykus Lee-Ann
Published: April 2015

Human noroviruses (NoVs) are the leading cause of foodborne illness in the United States, and they exact a considerable human and economic burden worldwide. In fact, the many challenging aspects of human NoV have caused some to call it the nearly perfect foodborne pathogen. In this review, a brief overview of NoVs and their genetic structure is provided. Additionally, the challenges and recent developments related to human NoVs regarding viral evolution, transmission, epidemiology, outbreak identification, cultivation, animal and human models, and detection are presented.
Diet-Based Strategies for Cancer Chemoprevention: The Role of Combination Regimens Using Dietary Bioactive Components
Authors: DiMarco-Crook Christina , Xiao Hang
Published: April 2015

Chemopreventive agents that the general population can consume for prolonged periods of time with minimal risk of any side effects are of great interest to all in search of a solution to the pervasive incidence of cancer. Dietary bioactive components have been found to modulate many deregulated molecular pathways associated with the initiation and progression of different types of cancer. Combination regimens with dietary bioactive components are a promising strategy for cancer chemoprevention because they may offer enhanced protective effects against cancer development but cause little or no adverse effects. This article provides an overview of studies examining the combination of dietary bioactive components for the chemoprevention of major types of cancer. A better understanding of existing research on the combination of dietary bioactive components will provide an important basis for the rational design of future combination studies and the successful development of cancer chemoprevention strategies.
Probabilistic Record Linkage in Astronomy: Directional Cross-Identification and Beyond
Authors: Budavári Tamás , Loredo Thomas J.
Published: April 2015

Modern astronomy increasingly relies upon systematic surveys, whose dedicated telescopes continuously observe the sky across varied wavelength ranges of the electromagnetic spectrum; some surveys also observe nonelectromagnetic messengers, such as high-energy particles or gravitational waves. Stars and galaxies look different through the eyes of different instruments, and their independent measurements have to be carefully combined to provide a complete, sound picture of the multicolor and eventful universe. The association of an object's independent detections is, however, a difficult problem scientifically, computationally, and statistically, raising varied challenges across diverse astronomical applications. The fundamental problem is finding records in survey databases with directions that match to within the direction uncertainties. Such astronomical versions of the record linkage problem are known by various terms in astronomy: cross-matching; cross-identification; and directional, positional, or spatiotemporal coincidence assessment. Astronomers have developed several statistical approaches for such problems, largely independent of related developments in other disciplines. Here, we review emerging approaches that compute (Bayesian) probabilities for the hypotheses of interest: possible associations or demographic properties of a cosmic population that depend on identifying associations. Many cross-identification tasks can be formulated within a hierarchical Bayesian partition model framework, with components that explicitly account for astrophysical effects (e.g., source brightness versus wavelength, source motion, or source extent), selection effects, and measurement error. We survey recent developments and highlight important open areas for future research.
Nasal high flow clears anatomical dead space in upper airway models
Authors: Möller Winfried , Celik Gülnaz , Feng Sheng , Bartenstein Peter , Meyer Gabriele , Eickelberg Oliver , Schmid Otmar , Tatkov Stanislav
Published: April 2015

Recent studies showed that nasal high flow (NHF) with or without supplemental oxygen can assist ventilation of patients with chronic respiratory and sleep disorders. The hypothesis of this study was to test whether NHF can clear dead space in two different models of the upper nasal airways. The first was a simple tube model consisting of a nozzle to simulate the nasal valve area, connected to a cylindrical tube to simulate the nasal cavity. The second was a more complex anatomically representative upper airway model, constructed from segmented CT-scan images of a healthy volunteer. After filling the models with tracer gases, NHF was delivered at rates of 15, 30, and 45 l/min. The tracer gas clearance was determined using dynamic infrared CO2 spectroscopy and 81mKr-gas radioactive gamma camera imaging. There was a similar tracer-gas clearance characteristic in the tube model and the upper airway model: clearance half-times were below 1.0 s and decreased with increasing NHF rates. For both models, the anterior compartments demonstrated faster clearance levels (half-times < 0.5 s) and the posterior sections showed slower clearance (half-times < 1.0 s). Both imaging methods showed similar flow-dependent tracer-gas clearance in the models. For the anatomically based model, there was complete tracer-gas removal from the nasal cavities within 1.0 s. The level of clearance in the nasal cavities increased by 1.8 ml/s for every 1.0 l/min increase in the rate of NHF. The study has demonstrated the fast-occurring clearance of nasal cavities by NHF therapy, which is capable of reducing of dead space rebreathing.
Risk Factors for Delayed Inpatient Functional Recovery after Total Knee Arthroplasty
Authors: Hoogeboom Thomas J. , van Meeteren Nico L. U. , Schank Kristin , Kim Raymond H. , Miner Todd , Stevens-Lapsley Jennifer E.
Published: April 2015

Purpose. To determine the predictive value of surgery-related variables for delayed inpatient functional recovery (i.e., ≥3 days to reach functional independence) after TKA.Method. 193 consecutive people undergoing TKA were included in this prospective cohort study. Inpatient functional recovery was measured daily using the Iowa Level of Assistance scale (ILAS). Two persons reviewed medical records to extract patient characteristics (i.e., age, sex, and BMI) and surgical factors (i.e., blood loss, tourniquet time, postoperative morphine use, and surgical experience). Odds ratios (OR) and area under the curves (AUC) were calculated to determine the predictive value of the putative factors and of the model on delayed functional recovery, respectively.Results. Delayed functional recovery was apparent in 76 (39%) people. Higher age, female sex, and higher BMI were all independent risk factors for delayed functional recovery (AUC (95%-CI); 0.72 (0.65–0.80)), whereas blood loss (OR (95%-CI); 1.00 (0.99–1.01)), tourniquet time (OR = 1.00 (0.98–1.02)), and postoperative morphine use (OR = 0.88 (0.37–2.06)) did not statistically improve the predictive value of the model, while surgical experience did (OR = 0.31 (0.16–0.64); AUC = 0.76 (0.69–83)).Conclusions. Surgery-related factors contribute little to the patient-related characteristics in a predictive model explaining delayed functional recovery after TKA in daily orthopaedic practice.
Biomarker Identification and Pathway Analysis by Serum Metabolomics of Lung Cancer
Authors: Chen Yingrong , Ma Zhihong , Min Lishan , Li Hongwei , Wang Bin , Zhong Jing , Dai Licheng
Published: April 2015

Lung cancer is one of the most common causes of cancer death, for which no validated tumor biomarker is sufficiently accurate to be useful for diagnosis. Additionally, the metabolic alterations associated with the disease are unclear. In this study, we investigated the construction, interaction, and pathways of potential lung cancer biomarkers using metabolomics pathway analysis based on the Kyoto Encyclopedia of Genes and Genomes database and the Human Metabolome Database to identify the top altered pathways for analysis and visualization. We constructed a diagnostic model using potential serum biomarkers from patients with lung cancer. We assessed their specificity and sensitivity according to the area under the curve of the receiver operator characteristic (ROC) curves, which could be used to distinguish patients with lung cancer from normal subjects. The pathway analysis indicated that sphingolipid metabolism was the top altered pathway in lung cancer. ROC curve analysis indicated that glycerophospho-N-arachidonoyl ethanolamine (GpAEA) and sphingosine were potential sensitive and specific biomarkers for lung cancer diagnosis and prognosis. Compared with the traditional lung cancer diagnostic biomarkers carcinoembryonic antigen and cytokeratin 19 fragment, GpAEA and sphingosine were as good or more appropriate for detecting lung cancer. We report our identification of potential metabolic diagnostic and prognostic biomarkers of lung cancer and clarify the metabolic alterations in lung cancer.
Survival Rate of Short, Locking Taper Implants with a Plateau Design: A 5-Year Retrospective Study
Authors: Demiralp Kemal Özgür , Akbulut Nihat , Kursun Sebnem , Argun Didem , Bagis Nilsun , Orhan Kaan
Published: April 2015

Background. Short implants have become popular in the reconstruction of jaws, especially in cases with limited bone height. Shorter implants, those with locking tapers and plateau root shapes, tend to have longer survival times. We retrospectively investigated the cumulative survival rates of Bicon short implants (<8 mm) according to patient variables over a 5-year period.Materials and Methods. This study included 111 consecutively treated patients with 371 implants supporting fixed or removable prosthetics. Data were evaluated to acquire cumulative survival rates according to gender, age, tobacco use, surgical procedure, bone quality, and restoration type. Statistics were performed using chi-square, Mann-Whitney, and Kruskal Wallis H tests.Results. The survival rate was 97.3% with, on average, 22.8 months of follow-up. Patients older than 60 years had higher failure rate than the other age groups (P<0.05). Placed region, age, and bone quality had adverse effects on survival rate in the <8 mm implant group with statistically significant difference (P<0.05).Conclusions. Approximately 23-month follow-up data indicate that short implants with locking tapers and plateau-type roots have comparable survival rates as other types of dental implants. However, due to limitations of study, these issues remain to be further investigated in future randomized controlled clinical trials.