bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Area Ratio Change Via Increased Hole Length for Shaped Film Cooling Holes With Constant Expansion Angles
Authors: Haydt Shane , Lynch Stephen , Lewis Scott
Published: January 2018

Shaped film cooling holes are used as a cooling technology in gas turbines to reduce metal temperatures and improve durability, and they generally consist of a small metering section connected to a diffuser that expands in one or more directions. The area ratio (AR) of these holes is defined as the area at the exit of the diffuser, divided by the area at the metering section. A larger AR increases the diffusion of the coolant momentum, leading to lower average momentum of the coolant jet at the exit of the hole and generally better cooling performance. Cooling holes with larger ARs are also more tolerant of high blowing ratio conditions, and the increased coolant diffusion typically better prevents jet lift-off from occurring. Higher ARs have traditionally been accomplished by increasing the expansion angle of the diffuser while keeping the overall length of the hole constant. The present study maintains the diffuser expansion angles and instead increases the length of the diffuser, which results in longer holes. Various ARs have been examined for two shaped holes: one with forward and lateral expansion angles of 7 deg (7-7-7 hole) and one with forward and lateral expansion angles of 12 deg (12-12-12 hole). Each hole shape was tested at numerous blowing ratios to capture trends across various flow rates. Adiabatic effectiveness measurements indicate that for the baseline 7-7-7 hole, a larger AR provides higher effectiveness, especially at higher blowing ratios. Measurements also indicate that for the 12-12-12 hole, a larger AR performs better at high blowing ratios but the hole experiences ingestion at low blowing ratios. Steady Reynolds-averaged Navier–Stokes simulations did not accurately predict the levels of adiabatic effectiveness, but did predict the trend of improving effectiveness with increasing AR for both hole shapes. Flowfield measurements with particle image velocimetry (PIV) were also performed at one downstream plane for a low and high AR case, and the results indicate an expected decrease in jet velocity due to a larger diffuser.
Stall Inception Analysis of Transonic Compressors With Chordwise and Axial Sweep
Authors: He Chen , Sun Dakun , Sun Xiaofeng
Published: January 2018

This paper concentrates on the stall inception analysis of transonic compressors with chordwise and axial sweep. A new prediction approach of stall inception is developed based on global stability analysis and immersed boundary theory, which makes it possible to take both the concrete blade geometry and the complicated base flow into consideration. The prediction of stall inception boils down to an eigenvalue problem. Spectral collocation method is adopted to discretize the eigenvalue equations and the eigenvalues are solved by using singular value decomposition method. The developed prediction approach is validated on two different typical transonic compressors, a single stage compressor and an isolated-rotor compressor, which shows a good agreement with the experimental data. The latter is adopted as a baseline rotor for the investigation of chordwise and axial sweep. By adjusting the stacking line of the baseline rotor, a series of swept rotors are modeled and the stall inception behavior of them is predicted by using the developed approach. The comparison of stall inception behaviors between these rotors is presented, and in combination with steady flow analyses, the effects of sweep features on the stall inception in transonic compressors are discussed.
Subpixel Temperature Measurements in Plasma Jet Environments Using High-Speed Multispectral Pyrometry
Authors: Fu Tairan , Liu Jiangfan , Duan Minghao , Li Sen
Published: January 2018

A high-speed (2 kHz) near-infrared (1.0–1.65 μm) multispectral pyrometer was used for noninvasive measurements of the subpixel temperature distribution near the sharp leading edge of a wing exposed to a supersonic plasma jet. The multispectral pyrometer operating in the field measurement mode was able to measure the spatial temperature distribution. Multiple spectra were used to determine the temperature distributions in the measurement region. The spatial resolution of the multispectral pyrometer was not restricted to one “pixel” but was extended to subpixel accuracy (the temperature distribution inside one pixel in the image space corresponding to the point region in the object space). Thus, this system gives high-speed, multichannel, and long working time spatial temperature measurements with a small data stream from high-speed multispectral pyrometers. The temperature distribution of the leading edge of a ceramic wing was investigated with the leading edge exposed to extreme convective heating from a high-enthalpy plasma flow. Simultaneous measurements with a multispectral pyrometer and an imaging pyrometer verify the measurement accuracy of the subpixel temperature distribution. Thus, this multispectral pyrometry can provide in situ noninvasive temperature diagnostics in supersonic plasma jet environments.
A New Approach for Centrifugal Impeller Preliminary Design and Aerothermal Analysis
Authors: Lou Fangyuan , Fabian John C. , Key Nicole L.
Published: January 2018

This paper introduces a new approach for the preliminary design and aerothermal analysis of centrifugal impellers using a relative diffusion effectiveness parameter. The relative diffusion effectiveness is defined as the ratio of the achieved diffusion to the maximum available diffusion in an impeller. It represents the quality of the relative diffusion process in an impeller. This parameter is used to evaluate impeller performance by correlating the relative diffusion effectiveness with the impeller isentropic efficiency using the experimental data acquired on a single-stage centrifugal compressor (SSCC). By including slip, which is appropriate considering it is an inviscid effect that should be included in the determination of maximum available diffusion in the impeller, a linear correlation between impeller efficiency and relative diffusion effectiveness resulted for all operating conditions. Additionally, a new method for impeller preliminary design was introduced using the relative diffusion effectiveness parameter, in which the optimal design is selected to maximize relative diffusion effectiveness. While traditional preliminary design methods are based on empirical loss models or empirical knowledge for selection of diffusion factor (DF) in the impeller, the new method does not require any such models, and it also provides an analytical approach for the selection of DF that gives optimal impeller performance. Validation of the method was performed using three classic impeller designs available in the open literature, and very good agreement was achieved. Furthermore, a sensitivity study shows that the method is robust in that the resulting flow angles at the impeller inlet and exit are insensitive to a wide range of blockage factors and various slip models.
A new species of Cosmolaelaps Berlese (Acari: Laelapidae) living in the nest of the ant Neoponera inversa (Smith) (Hymenoptera: Formicidae) in Brazil
Authors: Silva Virginia , Moreira Grazielle , Lopes Juliana , Delabie Jacques , Oliveira Anibal Ramadan
Published: January 2018

Until now the mite genus Cosmolaelps Berlese was represented in Brazil by eleven species. A new species, based on adults collected exclusively from the brood of the ponerine ant Neoponera inversa (Smith) (Hymenoptera: Formicidae) is described. Colonies of this ant were found in dried cocoa pods fallen on the floor of a cocoa tree plantation in southern Bahia. It is suggested that the mite uses the ant mainly for phoresy as these mostly arboreal ants, commonly change the site of their colony, quickly carrying the brood from one place to another.
Auditory-somatosensory bimodal stimulation desynchronizes brain circuitry to reduce tinnitus in guinea pigs and humans
Authors: Marks Kendra L. , Martel David T. , Wu Calvin , Basura Gregory J. , Roberts Larry E. , Schvartz-Leyzac Kara C. , Shore Susan E.
Published: January 2018

Noninvasive bimodal auditory stimulation targets the dorsal cochlear nucleus and reduces tinnitus in guinea pigs and humans.
Complete Genome Sequences of Two Multidrug-Resistant
Mycobacterium tuberculosis
Strains Isolated in Guiyang, China
Authors: Chen Zhenghong , Ou Weizheng , Fan Xiangyu , Cui Guzhen , Wang Qiong , Li Qiang , Sun Rong , Wu Xiaojuan , Qin Wan , Wang Yan
Published: January 2018

We identified the genome sequences of two
Mycobacterium tuberculosis
isolates. They were resistant to rifampin and isoniazid, as determined by the agar proportion method, but were susceptible to isoniazid, as determined by the DNA array method. The genome sequences showed that a
katG
deletion led to the false diagnosis of isoniazid resistance by DNA array.
Genome Sequence of the Bile Salt-Degrading Bacterium
Novosphingobium
sp. Strain Chol11, a Model Organism for Bacterial Steroid Catabolism
Authors: Yücel Onur , Wibberg Daniel , Philipp Bodo , Kalinowski Jörn
Published: January 2018

Many bacteria from different phylogenetic groups are able to degrade eukaryotic steroid compounds, but the underlying metabolic pathways are still not well understood.
Novosphingobium
sp. strain Chol11 is a steroid-degrading alphaproteobacterium. Its genome sequence reveals that it lacks several genes for steroid degradation known to exist in other model organisms.
Draft Genome Sequence of Singapore
Klebsiella pneumoniae
subsp.
pneumoniae
Isolate DS32358_14, Which Contains the Carbapenemase Gene
bla
VIM-1
Authors: Koh Tse H. , Abdul Rahman Nurdyana Binte , Teo Jeanette W. P. , La My-Van , Periaswamy Balamurugan , Chen Swaine L.
Published: January 2018

We sequenced the first
bla
VIM-1
-positive
Klebsiella pneumoniae
strain isolated in Singapore. The isolate belongs to multilocus sequence type 2542 (ST2542), and
bla
VIM-1
was the first gene in an integron that also contained
aacA4
,
aphA15
,
aadA1
,
catB2
,
qacEdelta1
, and
sul1
.
Draft Genome Sequences of Enterohemorrhagic and Enteropathogenic
Escherichia coli
Strains Isolated from Alpacas in Peru
Authors: Maturrano Lenin , Aleman Marjorie , Carhuaricra Dennis , Maximiliano Jorge , Siuce Juan , Luna Luis , Rosadio Raul
Published: January 2018

The draft genome sequences of two strains of
Escherichia coli
, isolated from alpacas in Peru, are reported here. ECA1 has been determined to be a strain of enterohemorrhagic
E. coli
and ECB1 a strain of enteropathogenic
E. coli
. These pathogens are responsible for hemolytic-uremic syndrome in humans and diarrhea in different mammals, respectively.
Draft Genome Sequence of
Streptomyces
sp. Strain JV178, a Producer of Clifednamide-Type Polycyclic Tetramate Macrolactams
Authors: Qi Yunci , D’Alessandro John M. , Blodgett Joshua A. V.
Published: January 2018

Here, we report the draft genome sequence of
Streptomyces
sp. JV178, a strain originating from Connecticut (USA) garden soil. This strain produces the polycyclic tetramate macrolactam compounds clifednamides A and B. The draft genome contains 10.65 Mb, 9,045 predicted protein coding sequences, and several natural product biosynthetic loci.
Draft Genome Sequences of
Pseudomonas putida
UV4 and UV4/95, Toluene Dioxygenase-Expressing Producers of
cis
-1,2-Dihydrodiols
Authors: Skvortsov Timofey , Hoering Patrick , Arkhipova Ksenia , Whitehead Roger C. , Boyd Derek R. , Allen Christopher C. R.
Published: January 2018

Here, we present draft genome sequences of
Pseudomonas putida
strains UV4 and UV4/95, which demonstrate an ability to conduct a wide range of industrially important biotransformations of arenes, alkenes, and phenols.
Draft Genome Sequence of
Rhodococcus
sp. Strain NCIMB 12038, a Naphthalene-Degrading Bacterium
Authors: Dandare Shamsudeen U. , Skvortsov Timofey , Arkhipova Ksenia , Allen Christopher C. R.
Published: January 2018

We report here the draft genome sequence of
Rhodococcus
sp. strain NCIMB 12038, an industrially important bacterium, possessing a large and diverse repertoire of genes involved in the biotransformation of various organic compounds, including naphthalene.
Draft Genome Sequence of a Violacein-Producing
Iodobacter
sp. from the Hudson Valley Watershed
Authors: Doing Georgia , Perron Gabriel G. , Jude Brooke A.
Published: January 2018

Iodobacter
species are among a number of freshwater Gram-negative violacein-producing bacteria.
Janthinobacterium lividum
and
Chromobacterium violaceum
have had their whole genomes sequenced and annotated. This is the first report of a draft whole-genome sequence of a violacein-producing
Iodobacter
strain that was isolated from the Hudson Valley watershed.
Genomic and Biochemical Characterization of Acinetobacter Podophage Petty Reveals a Novel Lysis Mechanism and Tail-Associated Depolymerase Activity
Authors: Hernandez-Morales A. C. , Lessor L. L. , Wood T. L. , Migl D. , Mijalis E. M. , Cahill J. , Russell W. K. , Young R. F. , Gill J. J.
Published: January 2018

The increased prevalence of drug-resistant, nosocomialAcinetobacterinfections, particularly from pathogenic members of theAcinetobacter calcoaceticus-baumanniicomplex, necessitates the exploration of novel treatments such as phage therapy. In the present study, we characterized phage Petty, a novel podophage that infects multidrug-resistantAcinetobacter nosocomialisandAcinetobacter baumannii. Genome analysis reveals that phage Petty is a 40,431-bp ϕKMV-like phage, with a coding density of 92.2% and a G+C content of 42.3%. Interestingly, the lysis cassette encodes a class I holin and a single-subunit endolysin, but it lacks canonical spanins to disrupt the outer membrane. Analysis of other ϕKMV-like genomes revealed that spaninless lysis cassettes are a feature of phages infectingAcinetobacterwithin this subfamily of bacteriophages. The observed halo surrounding Petty's large clear plaques indicated the presence of a phage-encoded depolymerase capable of degrading capsular exopolysaccharides (EPS). The product of gene 39, a putative tail fiber, was hypothesized to possess depolymerase activity based on weak homology to previously reported phage tail fibers. The 101.4-kDa protein gene product 39 (gp39) was cloned and expressed, and its activity againstAcinetobacterEPS in solution was determined. The enzyme degraded purified EPS from its host strainA. nosocomialisAU0783, reducing its viscosity, and generated reducing ends in solution, indicative of hydrolase activity. Given that the accessibility to cells within a biofilm is enhanced by degradation of EPS, phages with depolymerases may have enhanced diagnostic and therapeutic potential against drug-resistantAcinetobacterstrains.

IMPORTANCEBacteriophage therapy is being revisited as a treatment for difficult-to-treat infections. This is especially true forAcinetobacterinfections, which are notorious for being resistant to antimicrobials. Thus, sufficient data need to be generated with regard to phages with therapeutic potential, if they are to be successfully employed clinically. In this report, we describe the isolation and characterization of phage Petty, a novel lytic podophage, and its depolymerase. To our knowledge, it is the first phage reported to be able to infect bothA. baumanniiandA. nosocomialis. The lytic phage has potential as an alternative therapeutic agent, and the depolymerase could be used for modulating EPS both during infections and in biofilms on medical equipment, as well as for capsular typing. We also highlight the lack of predicted canonical spanins in the phage genome and confirm that, unlike the rounding of lambda lysogens lacking functional spanin genes,A. nosocomialiscells infected with phage Petty lyse by bursting. This suggests that phages like Petty employ a different mechanism to disrupt the outer membrane ofAcinetobacterhosts during lysis.
Recombinant Chimpanzee Adenovirus Vaccine AdC7-M/E Protects against Zika Virus Infection and Testis Damage
Authors: Xu Kun , Song Yufeng , Dai Lianpan , Zhang Yongli , Lu Xuancheng , Xie Yijia , Zhang Hangjie , Cheng Tao , Wang Qihui , Huang Qingrui , Bi Yuhai , Liu William J. , Liu Wenjun , Li Xiangdong , Qin Chuan , Shi Yi , Yan Jinghua , Zhou Dongming , Gao George F.
Published: January 2018

The recent outbreak of Zika virus (ZIKV) has emerged as a global health concern. ZIKV can persist in human semen and be transmitted by sexual contact, as well as by mosquitoes, as seen for classical arboviruses. We along with others have previously demonstrated that ZIKV infection leads to testis damage and infertility in mouse models. So far, no prophylactics or therapeutics are available; therefore, vaccine development is urgently demanded. Recombinant chimpanzee adenovirus has been explored as the preferred vaccine vector for many pathogens due to the low preexisting immunity against the vector among the human population. Here, we developed a ZIKV vaccine based on recombinant chimpanzee adenovirus type 7 (AdC7) expressing ZIKV M/E glycoproteins. A single vaccination of AdC7-M/E was sufficient to elicit potent neutralizing antibodies and protective immunity against ZIKV in both immunocompetent and immunodeficient mice. Moreover, vaccinated mice rapidly developed neutralizing antibody with high titers within 1 week postvaccination, and the elicited antiserum could cross-neutralize heterologous ZIKV strains. Additionally, ZIKV M- and E-specific T cell responses were robustly induced by AdC7-M/E. Moreover, one-dose inoculation of AdC7-M/E conferred mouse sterilizing immunity to eliminate viremia and viral burden in tissues against ZIKV challenge. Further investigations showed that vaccination with AdC7-M/E completely protected against ZIKV-induced testicular damage. These data demonstrate that AdC7-M/E is highly effective and represents a promising vaccine candidate for ZIKV control.

IMPORTANCE
Zika virus (ZIKV) is a pathogenic flavivirus that causes severe clinical consequences, including congenital malformations in fetuses and Guillain-Barré syndrome in adults. Vaccine development is a high priority for ZIKV control. In this study, to avoid preexisting anti-vector immunity in humans, a rare serotype chimpanzee adenovirus (AdC7) expressing the ZIKV M/E glycoproteins was used for ZIKV vaccine development. Impressively, AdC7-M/E exhibited exceptional performance as a ZIKV vaccine, as follows: (i) protective efficacy by a single vaccination, (ii) rapid development of a robust humoral response, (iii) durable immune responses, (iv) robust T cell responses, and (v) sterilizing immunity achieved by a single vaccination. These advantages of AdC7-M/E strongly support its potential application as a promising ZIKV vaccine in the clinic.
Cleavage of the C-Terminal Fragment of Reovirus μ1 Is Required for Optimal Infectivity
Authors: Snyder Anthony J. , Danthi Pranav
Published: January 2018

The mammalian orthoreovirus (reovirus) outer capsid, which is composed of 200 μ1/σ3 heterohexamers and a maximum of 12 σ1 trimers, contains all of the proteins that are necessary for attaching to and entering host cells. Following attachment, reovirus is internalized by receptor-mediated endocytosis and acid-dependent cathepsin proteases degrade the σ3 protein. This process generates a metastable intermediate, called infectious subviral particle (ISVP), in which the μ1 membrane penetration protein is exposed. ISVPs undergo a second structural rearrangement to deposit the genome-containing core into the host cytoplasm. The conformationally altered particle is called ISVP*. ISVP-to-ISVP* conversion culminates in the release of μ1 N- and C-terminal fragments, μ1N and Φ, respectively. Released μ1N is thought to facilitate core delivery by generating size-selective pores within the endosomal membrane, whereas the precise role of Φ, particularly in the context of viral entry, is undefined. In this report, we characterize a recombinant reovirus that fails to cleave Φ from μ1
in vitro
. Φ cleavage, which is not required for ISVP-to-ISVP* conversion, enhances the disruption of liposomal membranes and facilitates the recruitment of ISVP*s to the site of pore formation. Moreover, the Φ cleavage-deficient strain initiates infection of host cells less efficiently than the parental strain. These results indicate that μ1N and Φ contribute to reovirus pore forming activity.

IMPORTANCE
Host membranes represent a physical barrier that prevents infection. To overcome this barrier, viruses utilize diverse strategies, such as membrane fusion or membrane disruption, to access internal components of the cell. These strategies are characterized by discrete protein-protein and protein-lipid interactions. The mammalian orthoreovirus (reovirus) outer capsid undergoes a series of well-defined conformational changes, which conclude with pore formation and delivery of the viral genetic material. In this report, we characterize the role of the small, reovirus-derived Φ peptide in pore formation. Φ cleavage from the outer capsid enhances membrane disruption and facilitates the recruitment of virions to membrane-associated pores. Moreover, Φ cleavage promotes the initiation of infection. Together, these results reveal an additional component of the reovirus pore forming apparatus and highlight a strategy for penetrating host membranes.
Prevalence of keratoconus in paediatric patients in Riyadh, Saudi Arabia
Authors: Torres Netto Emilio Almeida , Al-Otaibi Wafa Majed , Hafezi Nikki L , Kling Sabine , Al-Farhan Haya M , Randleman J Bradley , Hafezi Farhad
Published: January 2018

Background/aim

Keratoconus (KC) is a ectatic corneal disorder with marked progression during childhood and puberty that may lead to severe visual loss. In addition to KC prevalence, estimate shows major geographical variations; recent studies using Scheimpflug technology are in contrast to the 1980s and 1990s literature. The present study aims to determine the prevalence of KC in paediatric patients in Riyadh, Saudi Arabia (KSA).

Methods

This prospective, cross-sectional, observational, multicentre study collected data from paediatric patients from 6 years and 21 years of age who were seen at multiple non-ophthalmic emergency departments within KSA. Bilateral corneal measurements were performed using a rotational Scheimpflug corneal tomography system. Two masked examiners established the diagnosis of KC using both objective and subjective screening criteria. Cohen’s kappa coefficient (κ) was used to qualitatively analyse the interexaminer agreement.

Results

There were 522 patients (1044 eyes) evaluated, with an average age of 16.8±4.2 years (range 6–21 years). KC prevalence was 5.56% for examiner 1 and 3.83% for examiner 2. The κ was 0.81 (almost perfect agreement), with discrepancy in nine cases, which were jointly evaluated and consensus obtained. Final KC prevalence was 4.79% (95% CI 2.96 to 6.62) or 1:21 patients.

Conclusions

The prevalence of KC among paediatric patients in the KSA is considerably higher than numbers reported from earlier studies and from similar studies in other countries. This increase might be due to geographical variations in disease prevalence or due to the ability of screening technology to detect undiagnosed KC with greater accuracy.
Compliance analysis of pedestrian facilities with accessibility requirements
Authors: Halabya Ayman , El-Rayes Khaled
Published: January 2018

State and local governments are required by law to provide and maintain accessibility on their pedestrian facilities. They need to conduct, document, and update self-evaluations to identify non-compliant pedestrian facilities. This paper presents the development of a novel model for analyzing the compliance of pedestrian facilities with accessibility requirements. The model provides original and unique capabilities that enable decision-makers to: (i) quantify the degree of non-compliance of all types of pedestrian facilities including transit stops, on-street parking, and passenger loading zones; (ii) estimate cost and labour-hours needed to achieve compliance; (iii) prioritize upgrade projects for pedestrian facility types; (iv) rank pedestrian facilities upgrade projects in multiple geographical regions based on their collective degree of non-compliance; and (v) classify pedestrian facilities based on the type of required upgrade. A case study that includes 1327 pedestrian facilities is analyzed to evaluate the performance of the developed model and illustrate its capabilities.
Factor-based target cost modelling for construction projects
Authors: Alwisy Aladdin , Bouferguene Ahmed , Al-Hussein Mohamed
Published: January 2018

Target value design (TVD) principles set the main guidelines for the design-estimate process that allow the efficient exploration of available construction alternatives, thereby helping construction companies to reduce cost-to-design, cost-to-build, and improve the quality of construction projects. The successful application of TVD requires a clear understanding of the interactions among construction components. The proposed target cost modelling approach introduces an algorithmic factor-based framework to advance TVD that supports the design-estimate process by examining the relationships among building components, their direct and indirect impact on project overall cost and value. Construction factors control compatibility and performance analysis among available construction alternatives. Costing factors contribute to the development of mathematical costing models capable of automatically calculating the cost of compatible alternatives. Finally, rule-based analysis, developed under an appropriate programming environment, executes alternative value analysis to develop a detailed estimate with an improved overall value for construction projects.
A Diagrammatic Representation of Phase Portraits and Bifurcation Diagrams of Two-Dimensional Dynamical Systems
Authors: Roulet Javier , Mindlin Gabriel B.
Published: January 2018

We treat the problem of characterizing in a systematic way the qualitative features of two-dimensional dynamical systems. To that end, we construct a representation of the topological features of phase portraits by means of diagrams that discard their quantitative information. All codimension 1 bifurcations are naturally embodied in the possible ways of transitioning smoothly between diagrams. We introduce a representation of bifurcation curves in parameter space that guides the proposition of bifurcation diagrams compatible with partial information about the system.
Bounding the Number of Zeros of Abelian Integral for a Class of Integrable non-Hamilton System
Authors: Sui Shiyou , Li Baoyi
Published: January 2018

This paper investigates the planar differential systems [Formula: see text], [Formula: see text] under the perturbations of polynomials of [Formula: see text] with degree [Formula: see text], where [Formula: see text] with [Formula: see text] and [Formula: see text]. The upper bound for the number of zeros of Abelian integral from the period annulus around the center is obtained.
Generating a Double-Scroll Attractor by Connecting a Pair of Mutual Mirror-Image Attractors via Planar Switching Control
Authors: Sun Changchun , Chen Zhongtang , Xu Qicheng
Published: January 2018

An original three-dimensional (3D) smooth continuous chaotic system and its mirror-image system with eight common parameters are constructed and a pair of symmetric chaotic attractors can be generated simultaneously. Basic dynamical behaviors of two 3D chaotic systems are investigated respectively. A double-scroll chaotic attractor by connecting the pair of mutual mirror-image attractors is generated via a novel planar switching control approach. Chaos can also be controlled to a fixed point, a periodic orbit and a divergent orbit respectively by switching between two chaotic systems. Finally, an equivalent 3D chaotic system by combining two 3D chaotic systems with a switching law is designed by utilizing a sign function. Two circuit diagrams for realizing the double-scroll attractor are depicted by employing an improved module-based design approach.
Analysis of Noise-Induced Bifurcations in the Stochastic Tritrophic Population System
Authors: Bashkirtseva Irina , Ryashko Lev , Ryazanova Tatyana
Published: January 2018

A problem on the analysis of the noise-induced transitions in stochastically forced tritrophic population systems is considered. We study this problem on the basis of the conceptual “prey–predator-top predator” model which possesses coexisting attractors (limit cycles) and exhibits noise-induced transitions between them. For the parametric analysis of noise-induced phenomena in this nonlinear 3D model, we suggest a constructive approach combining the stochastic sensitivity function technique and confidence domain method. We show how increasing noise causes stochastic bifurcations, generation of mixed-mode oscillations, and transitions from order to chaos.
Stability and Hopf Bifurcation of Fractional-Order Complex-Valued Single Neuron Model with Time Delay
Authors: Wang Zhen , Wang Xiaohong , Li Yuxia , Huang Xia
Published: January 2018

In this paper, the problems of stability and Hopf bifurcation in a class of fractional-order complex-valued single neuron model with time delay are addressed. With the help of the stability theory of fractional-order differential equations and Laplace transforms, several new sufficient conditions, which ensure the stability of the system are derived. Taking the time delay as the bifurcation parameter, Hopf bifurcation is investigated and the critical value of the time delay for the occurrence of Hopf bifurcation is determined. Finally, two representative numerical examples are given to show the effectiveness of the theoretical results.
MULTIFRACTAL CHARACTERISTICS OF AXISYMMETRIC JET TURBULENCE INTENSITY FROM RANS NUMERICAL SIMULATION
Authors: SEO YONGWON , KO HAENG SIK , SON SANGYOUNG
Published: January 2018

A turbulent jet bears diverse physical characteristics that have been unveiled yet. Of particular interest is to analyze the turbulent intensity, which has been a key factor to assess and determine turbulent jet performance since diffusive and mixing conditions are largely dependent on it. Multifractal measures are useful in terms of identifying characteristics of a physical quantity distributed over a spatial domain. This study examines the multifractal exponents of jet turbulence intensities obtained through numerical simulation. We acquired the turbulence intensities from numerical jet discharge experiments, where two types of nozzle geometry were tested based on a Reynolds-Averaged Navier–Stokes (RANS) equations. The [Formula: see text]-[Formula: see text] model and [Formula: see text]-[Formula: see text] model were used for turbulence closure models. The results showed that the RANS model successfully regenerates transversal velocity profile, which is almost identical to an analytical solution. The RANS model also shows the decay of turbulence intensity in the longitudinal direction but it depends on the outfall nozzle lengths. The result indicates the existence of a common multifractal spectrum for turbulence intensity obtained from numerical simulation. Although the transverse velocity profiles are similar for two different turbulence models, the minimum Lipschitz–Hölder exponent [Formula: see text] and entropy dimension [Formula: see text] are different. These results suggest that the multifractal exponents capture the difference in turbulence structures of hierarchical turbulence intensities produced by different turbulence models.
MULTIFRACTAL ANALYSIS OF SEISMICALLY INDUCED SOFT-SEDIMENT DEFORMATION STRUCTURES IMAGED BY X-RAY COMPUTED TOMOGRAPHY
Authors: NAKASHIMA YOSHITO , KOMATSUBARA JUNKO
Published: January 2018

Unconsolidated soft sediments deform and mix complexly by seismically induced fluidization. Such geological soft-sediment deformation structures (SSDSs) recorded in boring cores were imaged by X-ray computed tomography (CT), which enables visualization of the inhomogeneous spatial distribution of iron-bearing mineral grains as strong X-ray absorbers in the deformed strata. Multifractal analysis was applied to the two-dimensional (2D) CT images with various degrees of deformation and mixing. The results show that the distribution of the iron-bearing mineral grains is multifractal for less deformed/mixed strata and almost monofractal for fully mixed (i.e. almost homogenized) strata. Computer simulations of deformation of real and synthetic digital images were performed using the egg-beater flow model. The simulations successfully reproduced the transformation from the multifractal spectra into almost monofractal spectra (i.e. almost convergence on a single point) with an increase in deformation/mixing intensity. The present study demonstrates that multifractal analysis coupled with X-ray CT and the mixing flow model is useful to quantify the complexity of seismically induced SSDSs, standing as a novel method for the evaluation of cores for seismic risk assessment.
On Stress Concentration on Edges of Defect Holes in Plates and Critical Issues on Filling-in Repairs
Authors: Duan S. Y. , Zhang Z. M. , Han X. , Liu G. R.
Published: January 2018

Repair is now increasingly used for damaged structures due to its distinguished advantages in prolonging the service life of structures, substantial saving in materials, and preservation of related crucial resources. This work presents a novel filling-in repair procedure for localized damages in panel structures, and conducts a series of theory and numerical studies to examine the repair effects in terms of stress concentration. It aims providing some fundamental understandings important in the design of repairing procedures for effective filling-in repairs to mitigate stress concentrations. First, the damaged zone (or cracks) is “cut-off” by simply drilling a hole through the panel to remove possible stress singularity. The hole is then filled-in with a circular patch of slightly smaller diameter made of similar material of the panel using adhesives. Stress concentration is then investigated to reveal the possible ranges of the stress concentration factors (SCF), through both analytical and numerical means using finite element (FE) models. The repair effects are then examined for repaired plates with filled-in holes in terms of SCF reduction, comparing with plates with open-holes. Both aluminum and composite plates are studied, and the filling-in repairs are carried out using epoxy adhesives. It is found that the SCF increases with the adhesive thickness, decreases with hole radius and Young’s modulus of adhesives. Parametric studies are performed to produce two-stage curve-fitted formulae for SCF predictions from given hole radius, physical properties and thickness of the adhesive layer, which are useful for the design and assessment of the repairs, leading to a prolonged life of services of structures.
An Adaptive Orthogonal SSA Decomposition Algorithm for a Time Series
Authors: Kume Kenji , Nose-Togawa Naoko
Published: January 2018

Singular spectrum analysis (SSA) is a nonparametric spectral decomposition of a time series into arbitrary number of interpretable components. It involves a single parameter, window length [Formula: see text], which can be adjusted for the specific purpose of the analysis. After the decomposition of a time series, similar series are grouped to obtain the interpretable components by consulting with the [Formula: see text]-correlation matrix. To accomplish better resolution of the frequency spectrum, a larger window length [Formula: see text] is preferable and, in this case, the proper grouping is crucial for making the SSA decomposition. When the [Formula: see text]-correlation matrix does not have block-diagonal form, however, it is hard to adequately carry out the grouping. To avoid this, we propose a novel algorithm for the adaptive orthogonal decomposition of the time series based on the SSA scheme. The SSA decomposition sequences of the time series are recombined and the linear coefficients are determined so as to maximizing its squared norm. This results in an eigenvalue problem of the Gram matrix and we can obtain the orthonormal basis vectors for the [Formula: see text]-dimensional subspace. By the orthogonal projection of the original time series on these basis vectors, we can obtain adaptive orthogonal decomposition of the time series without the redundancy of the original SSA decomposition.
Mining Electronic Health Records (EHRs)
Authors: Yadav Pranjul , Steinbach Michael , Kumar Vipin , Simon Gyorgy
Published: January 2018

The continuously increasing cost of the US healthcare system has received significant attention. Central to the ideas aimed at curbing this trend is the use of technology in the form of the mandate to implement electronic health records (EHRs). EHRs consist of patient information such as demographics, medications, laboratory test results, diagnosis codes, and procedures. Mining EHRs could lead to improvement in patient health management as EHRs contain detailed information related to disease prognosis for large patient populations. In this article, we provide a structured and comprehensive overview of data mining techniques for modeling EHRs. We first provide a detailed understanding of the major application areas to which EHR mining has been applied and then discuss the nature of EHR data and its accompanying challenges. Next, we describe major approaches used for EHR mining, the metrics associated with EHRs, and the various study designs. With this foundation, we then provide a systematic and methodological organization of existing data mining techniques used to model EHRs and discuss ideas for future research.
Graph Processing on GPUs
Authors: Shi Xuanhua , Zheng Zhigao , Zhou Yongluan , Jin Hai , He Ligang , Liu Bo , Hua Qiang-Sheng
Published: January 2018

In the big data era, much real-world data can be naturally represented as graphs. Consequently, many application domains can be modeled as graph processing. Graph processing, especially the processing of the large-scale graphs with the number of vertices and edges in the order of billions or even hundreds of billions, has attracted much attention in both industry and academia. It still remains a great challenge to process such large-scale graphs. Researchers have been seeking for new possible solutions. Because of the massive degree of parallelism and the high memory access bandwidth in GPU, utilizing GPU to accelerate graph processing proves to be a promising solution. This article surveys the key issues of graph processing on GPUs, including data layout, memory access pattern, workload mapping, and specific GPU programming. In this article, we summarize the state-of-the-art research on GPU-based graph processing, analyze the existing challenges in detail, and explore the research opportunities for the future.
Constraint-Based Refactoring
Authors: Steimann Friedrich
Published: January 2018

Constraint-based refactoring generalizes constraint-based type refactoring as introduced by Tip et al. [61] by extending the coverage of change from types to names, locations, accessibilities, and other properties of program elements. Starting with a generic specification of refactoring tools, we systematically develop constraint-based refactoring as a generic solution to a certain class of refactoring problems and provide a condition under which constraint-based refactoring tools are proven correct for any given target language. Although compliance with this correctness condition is hard to prove for target languages whose semantics is not formally defined, we show how the condition gives rise to automated testing procedures. We present a novel algorithm based on constraint-logic programming for the generation of constraints from a program to be refactored, and demonstrate its time and space requirements by using it in the application of refactorings to open source programs. Summarizing earlier work, we show how the principles underlying constraint-based refactoring tools extend to ad hoc refactoring, cross-language refactoring, and model/code co-refactoring.
Conditioning in Probabilistic Programming
Authors: Olmedo Federico , Gretz Friedrich , Jansen Nils , Kaminski Benjamin Lucien , Katoen Joost-Pieter , Mciver Annabelle
Published: January 2018

This article investigates the semantic intricacies of conditioning, a main feature in probabilistic programming. Our study is based on an extension of the imperative probabilistic guarded command language pGCL with conditioning. We provide a weakest precondition (wp) semantics and an operational semantics. To deal with possibly diverging program behavior, we consider liberal preconditions. We show that diverging program behavior plays a key role when defining conditioning. We establish that weakest preconditions coincide with conditional expected rewards in Markov chains—the operational semantics—and that the wp-semantics conservatively extends the existing semantics of pGCL (without conditioning). An extension of these results with nondeterminism turns out to be problematic: although an operational semantics using Markov decision processes is rather straightforward, we show that providing an inductive wp-semantics in this setting is impossible. Finally, we present two program transformations that eliminate conditioning from any program. The first transformation hoists conditioning while updating the probabilistic choices in the program, while the second transformation replaces conditioning—in the same vein as rejection sampling—by a program with loops. In addition, we present a last program transformation that replaces an independent identically distributed loop with conditioning.
Improving Marine Ecosystem Models with Biochemical Tracers
Authors: Pethybridge Heidi R. , Choy C. Anela , Polovina Jeffrey J. , Fulton Elizabeth A.
Published: January 2018

Empirical data on food web dynamics and predator-prey interactions underpin ecosystem models, which are increasingly used to support strategic management of marine resources. These data have traditionally derived from stomach content analysis, but new and complementary forms of ecological data are increasingly available from biochemical tracer techniques. Extensive opportunities exist to improve the empirical robustness of ecosystem models through the incorporation of biochemical tracer data and derived indices, an area that is rapidly expanding because of advances in analytical developments and sophisticated statistical techniques. Here, we explore the trophic information required by ecosystem model frameworks (species, individual, and size based) and match them to the most commonly used biochemical tracers (bulk tissue and compound-specific stable isotopes, fatty acids, and trace elements). Key quantitative parameters derived from biochemical tracers include estimates of diet composition, niche width, and trophic position. Biochemical tracers also provide powerful insight into the spatial and temporal variability of food web structure and the characterization of dominant basal and microbial food web groups. A major challenge in incorporating biochemical tracer data into ecosystem models is scale and data type mismatches, which can be overcome with greater knowledge exchange and numerical approaches that transform, integrate, and visualize data.
The Bottom Boundary Layer
Authors: Trowbridge John H. , Lentz Steven J.
Published: January 2018

The oceanic bottom boundary layer extracts energy and momentum from the overlying flow, mediates the fate of near-bottom substances, and generates bedforms that retard the flow and affect benthic processes. The bottom boundary layer is forced by winds, waves, tides, and buoyancy and is influenced by surface waves, internal waves, and stratification by heat, salt, and suspended sediments. This review focuses on the coastal ocean. The main points are that (a) classical turbulence concepts and modern turbulence parameterizations provide accurate representations of the structure and turbulent fluxes under conditions in which the underlying assumptions hold, (b) modern sensors and analyses enable high-quality direct or near-direct measurements of the turbulent fluxes and dissipation rates, and (c) the remaining challenges include the interaction of waves and currents with the erodible seabed, the impact of layer-scale two- and three-dimensional instabilities, and the role of the bottom boundary layer in shelf-slope exchange.
A Time‐Domain Active Vibration Control Algorithm for Helicopter Based on a Prior Error Channel Identification Strategy
Authors: Lu Yang , Feng Jianbo
Published: January 2018

During the flight tests of Z‐11 helicopter, the previous method for active vibration control of helicopter suffered from the problems of slow convergence speed and big residual vibration. In order to mitigate these problems, a new method was proposed on the basis of the previous one. Here, a new error channel modeling method is used, which is named the prior error channel identification strategy. And the active control process and the error channel identification process are simplified to improve performance of the system. Besides, the complexity of the method is reduced. Active vibration control simulations were performed based on a simplified model of helicopter fuselage. The simulation results show that the proposed method has lower residual vibration, faster convergence speed, and better capacity for resisting disturbance compared with the previous method. Finally, an active control of structure response experiment was conducted on a free‐free beam, and good inhibitory effect of the vibration response of the free‐free beam was obtained. The results illustrate that the proposed method based on the prior error channel identification strategy is effective.
Effect of Riociguat and Sildenafil on Right Heart Remodeling and Function in Pressure Overload Induced Model of Pulmonary Arterial Banding
Authors: Rai Nabham , Veeroju Swathi , Schymura Yves , Janssen Wiebke , Wietelmann Astrid , Kojonazarov Baktybek , Weissmann Norbert , Stasch Johannes-Peter , Ghofrani Hossein Ardeschir , Seeger Werner , Schermuly Ralph Theo , Novoyatleva Tatyana
Published: January 2018

Pulmonary arterial hypertension (PAH) is a progressive disorder characterized by remodeling of the pulmonary vasculature and a rise in right ventricular (RV) afterload. The increased RV afterload leads to right ventricular failure (RVF) which is the reason for the high morbidity and mortality in PAH patients. The objective was to evaluate the therapeutic efficacy and antiremodeling potential of the phosphodiesterase type 5 (PDE5) inhibitor sildenafil and the soluble guanylate cyclase stimulator riociguat in a model of pressure overload RV hypertrophy induced by pulmonary artery banding (PAB). Mice subjected to PAB, one week after surgery, were treated with either sildenafil (100 mg/kg/d, n=5), riociguat (30 mg/kg/d, n=5), or vehicle (n=5) for 14 days. RV function and remodeling were assessed by right heart catheterization, magnetic resonance imaging (MRI), and histomorphometry. Both sildenafil and riociguat prevented the deterioration of RV function, as determined by a decrease in RV dilation and restoration of the RV ejection fraction (EF). Although both compounds did not decrease right heart mass and cellular hypertrophy, riociguat prevented RV fibrosis induced by PAB. Both compounds diminished TGF-beta1 induced collagen synthesis of RV cardiac fibroblasts in vitro. Treatment with either riociguat or sildenafil prevented the progression of pressure overload-induced RVF, representing a novel therapeutic approach.