bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation on Heat Transfer Characteristics of a Cooling Channel With Dense Array of Angled Rib Turbulators
Authors: Hagari Tomoko , Ishida Katsuhiko , Takeishi Ken-ichiro , Oda Yutaka , Kitada Hiroki 
Published: August 2013

Heat transfer characteristics of a cooling channel with densely arranged, angled rib turbulators were investigated experimentally and numerically. The dense arrangement of the ribs is one of the potential candidates to improve heat transfer performance because of its surface area enlargement effect.
The square test channel consisted of six square ribs, which were placed on one side. The ribs were arranged with a rib height to channel hydraulic diameter ratio (e/Dh) of 0.13, an angle of attack to the mainstream of 60deg, and rib pitch-to-height ratios (P/e) of 3, 6 and 10. Local heat transfer distribution on all surfaces of the rib and the floor surface between the ribs were measured by the naphthalene sublimation method. Channel Reynolds number ranges from 30,000 to 70,000. Measured data showed that the P/e of 3 provided the largest total heat transfer. It was found that 60% of heat flux was transferred through the rib surface.
Numerical simulations using a Reynolds-Averaged Navier-Stokes (RANS) method and a Large Eddy Simulation (LES) were carried out for the above test cases. The RANS underestimated the experimental heat transfer data by 40–50% for all rib surfaces with close rib arrangement. On the other hand, time-averaged heat transfer distribution obtained by LES showed better agreement with experimental data. Moreover, the LES predicted the periodic large vortex structure ranging over several rib pitches. Further investigation is expected on the periodic secondary flow and the application of LES to the prediction of heat transfer in the near future.
Computational Predictions of Aero-Thermal Performance of a Turbine Filleted Blade Cascade With Endwall Film Cooling
Authors: Barigozzi G. , Ravelli S. , Maritano M. , Abram R. 
Published: August 2013

In this study computational fluid dynamic simulations of a turbine blade with endwall film cooling were compared to measurements of both aerodynamic and thermal performance. The experimental data were collected at low Mach number (Ma2is = 0.3) in a linear cascade arrangement with 7 blades which geometry is typical of first stage high pressure turbine. A junction between the blade hub and the platform is provided by a 3D fillet. Coolant is injected through ten cylindrical holes distributed along the blade pressure side. Coolant to mainstream mass flow ratio was set to assure an inlet blowing ratio of M1 = 2.4 and M1 = 3.2. The simulations were carried out using the Shear Stress Transport (SST) k-ω turbulence model. Numerical predictions were compared against experimentally measured secondary flows and endwall film cooling effectiveness, at different injection conditions.
Simulation results agreed with the experiments for what concerns the general shape and the location of secondary flows. However, some limitations in the modeling were highlighted when going into the details of loss computation and vortex structure. Predictions overestimated both secondary and midspan blade wake losses. Moreover, the effect of the fillet on the aerodynamic flow features was not fully captured. Predicted film cooling results showed the sweeping of coolant across the passage in agreement with experiments even though jets persistency was higher than that measured. Levels of adiabatic effectiveness were generally well simulated.
Effects of Periodic Unsteady Inflow on Film Cooling and Heat Transfer on Highly Loaded High Pressure Turbine Blades With Flow Separation
Authors: Gomes Reinaldo A. , Niehuis Reinhard 
Published: August 2013

Film cooling experiments were run at the High-Speed Cascade Wind Tunnel of the University of the Federal Armed Forces Munich. The investigations were carried out on a linear cascade of highly loaded turbine blades. The main targets of the tests were to assess the film cooling effectiveness and the heat transfer in zones with main flow separation. The previous cascade was designed to have a large zone with flow separation on the pressure side starting at the leading edge and reaching up to approximately half of the axial chord. This cascade was changed for a new design with a larger pitch to chord ratio in order to set the focus on flow separation on the suction side. This increased pitch forces a massive separation on the suction side due to strong shocks. The flow separation is controlled with aid of vortex generating jets in order to reduce the total pressure loss caused by it. Film cooling is provided on the suction side upstream of the vortex generating jets.
The measurements comprise of blade loading, profile loss, adiabatic film cooling effectiveness and heat transfer coefficient under two Mach numbers at a Reynolds number of 390,000. In a previous publication detailed results with homogeneous inflow where shown. Now, the focus is set on the effects of periodic unsteady wakes resulting from bars moving upstream of the cascade. These moving bars create a periodic unsteady inflow similar to the interaction between stator and rotor in the machine. It is shown how these wakes have significant influence on the heat transfer in the acceleration region of the suction side and affect the adiabatic film cooling effectiveness upstream of the shock.
CFD Simulations of Unsteady Wakes on a Highly Loaded Low Pressure Turbine Airfoil (L1A)
Authors: Ibrahim Mounir B. , Vinci Samuel , Kartuzova Olga , Volino Ralph J. 
Published: August 2013

A study of a very high lift, low-pressure turbine airfoil in the presence of unsteady wakes was performed computationally and compared against experimental results. The experiments were conducted in a low speed wind tunnel under high (4.9%) and then low (0.6%) freestream turbulence intensity conditions with a flow coefficient (ζ) of 0.7. The experiments were done on a linear cascade with wakes that were produced from moving rods upstream of the cascade with the rod to blade spacing varied from 1 to 1.6 to 2. In the present study two different Reynolds numbers (25,000 and 50,000, based on the suction surface length and the nominal exit velocity from the cascade) were considered.
The experimental and computational data have shown that in cases without wakes, the boundary layer separated and did not reattach. The CFD was performed with Large Eddy Simulation (LES) and Unsteady Reynolds-Averaged Navier-Stokes (URANS), Transition-SST, utilizing the finite-volume code ANSYS FLUENT under the same freestream turbulence and Reynolds number conditions as the experiment but only at a rod to blade spacing of 1.
With wakes, separation was largely suppressed, particularly if the wake passing frequency was sufficiently high. Similar effect was predicted by 3D CFD simulations. Computational results for the pressure coefficients and velocity profiles were in a reasonable agreement with experimental ones for all cases examined. The 2D CFD efforts failed to capture the three dimensionality effects of the wake and thus were less consistent with the experimental data.
As a further computational study, cases were run to simulate higher wake passing frequencies which were not run experimentally. The results of these computational cases showed that an initial 25% increase from the experimental dimensionless wake passing frequency of F = 0.45 greatly reduced the size of the separation bubble, nearly completely suppressing it, however an additional 33% increase on top of this did not prove to have much of an effect.
Conjugate Heat Transfer Calculations on GT Rotor Blade for Industrial Applications: Part II—Improvement of External Flow Modeling
Authors: Andreini A. , Bonini A. , Da Soghe R. , Facchini B. , Ciani A. , Innocenti L. 
Published: August 2013

Gas turbine design has been characterized over the years by a continuous increase of the maximum cycle temperature, justified by a corresponding increase of cycle efficiency and power output. In such way turbine components heat load management has become a compulsory activity and then, a reliable procedure to evaluate the blades and vanes metal temperatures, is, nowadays, a crucial aspect for a safe components design.
This two part work presents a three-dimensional conjugate heat transfer procedure developed in the framework of an internal research project of GE Oil & Gas. The procedure, applied to the first rotor blade of the MS5002E gas turbine, consists in a decoupled analysis in which the internal cooling system was modeled by an in-house one dimensional thermo-fluid network solver, the external heat loads and pressure distribution have been evaluated through 3D CFD and the heat conduction in the solid is carried out through a 3D FEM solution.
The second part of this work is focused on the improvement of external heat loads prediction through the use of a full featured geometry of the blade. In particular a detailed representation of the rim seal is accounted for as well as the actual geometry of the squealer tip. A new set of conjugate results is compared with temperature obtained by metallographic analysis, pointing out the relevant effect of the actual endwall contour on the metal temperature distribution at low spans of the blade.
Aeroperformance Measurements for a Fully Cooled High-Pressure Turbine Stage
Authors: Haldeman Charles , Dunn Michael , Mathison Randall , Troha William , Vander Hoek Timothy , Riahi Ardeshir 
Published: August 2013

A detailed aero performance measurement program utilizing fully cooled engine hardware (high-pressure turbine stage) supplied by Honeywell Aerospace Advanced Technology Engines is described. The primary focus of this work was obtaining relevant aerodynamic data for a small turbine stage operating at a variety of conditions, including changes in operating conditions, geometry, and cooling parameters. The work extraction and the overall stage performance for each of these conditions can be determined using the measured acceleration rate of the turbine disk, the previously measured moment of inertia of the rotating system, and the mass flow through the turbine stage.
Measurements were performed for two different values of tip/shroud clearance and two different blade tip configurations. The vane and blade cooling mass flow could be adjusted independently and set to any desired value including totally off. A wide range of stage pressure ratios, coolant to freestream temperature ratios, and corrected speeds were used during the course of the investigation. A combustor emulator controlled the free stream inlet gas temperature, enabling variation of the temperature ratios and investigation of their effects on aero performance.
The influence of tip/shroud gap is clearly seen in this experiment. Improvements in specific work and efficiency achieved by reducing the tip/shroud clearance depend upon the specific values of stage pressure ratio and corrected speed. The maximum change of 3% to 4% occurs at a stage pressure ratio and corrected speed greater than the initial design point intent. The specific work extraction and efficiency for two different blade tip sets (one damaged from a rub and one original) were compared in detail. In general, the tip damage only had a very small effect on the work extraction for comparable conditions. The specific work extraction and efficiency were influenced by the presence of cooling gas and by the temperature of the cooling gas relative to the free stream gas temperature and the metal temperature. These same parameters were influenced by the magnitude of the vane inlet gas total temperature relative to the vane metal temperature and the coolant gas temperature.
Optimal Media for Use in Air Sampling To Detect Cultivable Bacteria and Fungi in the Pharmacy
Authors: Weissfeld Alice S. , Joseph Riya Augustin , Le Theresa V. , Trevino Ernest A. , Schaeffer M. Frances , Vance Paula H. 
Published: August 2013

ABSTRACT

Current guidelines for air sampling for bacteria and fungi in compounding pharmacies require the use of a medium for each type of organism. U.S. Pharmacopeia (USP) chapter <797> (
http://www.pbm.va.gov/linksotherresources/docs/USP797PharmaceuticalCompoundingSterileCompounding.pdf
) calls for tryptic soy agar with polysorbate and lecithin (TSApl) for bacteria and malt extract agar (MEA) for fungi. In contrast, the Controlled Environment Testing Association (CETA), the professional organization for individuals who certify hoods and clean rooms, states in its 2012 certification application guide (
http://www.cetainternational.org/reference/CAG-009v3.pdf?sid=1267
) that a single-plate method is acceptable, implying that it is not always necessary to use an additional medium specifically for fungi. In this study, we reviewed 5.5 years of data from our laboratory to determine the utility of TSApl versus yeast malt extract agar (YMEA) for the isolation of fungi. Our findings, from 2,073 air samples obtained from compounding pharmacies, demonstrated that the YMEA yielded >2.5 times more fungal isolates than TSApl.
Rombencephalitis Caused by Francisella tularensis
Authors: Barbaz M. , Piau C. , Tadie J. M. , Pelloux I. , Kayal S. , Tattevin P. , Le Tulzo Y. , Revest M. 
Published: August 2013

ABSTRACT

Common presentations of tularemia include pneumonia and ulceroglandular, oropharyngeal, or typhoidal disease. Neuromeningeal involvement is extremely rare. We report a case of a severe rhombencephalitis due to
Francisella tularensis
. Diagnosis was possible thanks to a very precise interview, and the patient dramatically improved after specific antibiotherapy.
Possible Involvement of Human Bocavirus 1 in the Death of a Middle-Aged Immunosuppressed Patient
Authors: Sadeghi Mohammadreza , Kantola Kalle , Finnegan Damian P. J. , McCaughey Conall , Hedman Lea , Söderlund-Venermo Maria , Hedman Klaus 
Published: August 2013

ABSTRACT
An immunosuppressed 61-year-old man went to the hospital with fever, nonproductive cough, and increasing shortness of breath. The subject died 8 days later of respiratory complications. PCR of respiratory samples as well as a blood sample revealed exceptionally high DNA levels of the emerging pathogen, human bocavirus 1 (HBoV1), a recently found pathogen associated with respiratory symptoms in young children. We describe the clinical progression of the case and discuss the potential role of HBoV1 in the outcome.
Clinical Significance and Molecular Characterization of Nonsporulating Molds Isolated from the Respiratory Tracts of Bronchopulmonary Mycosis Patients with Special Reference to Basidiomycetes
Authors: Singh Pradeep Kumar , Kathuria Shallu , Agarwal Kshitij , Gaur Shailendra Nath , Meis Jacques F. , Chowdhary Anuradha 
Published: August 2013

ABSTRACT

Nonsporulating molds (NSMs), especially basidiomycetes, have predominantly been reported as human pathogens responsible for allergic and invasive disease. Their conventional identification is problematic, as many isolates remain sterile in culture. Thus, inconclusive culture reports might adversely affect treatment decisions. The clinical significance of NSMs in pulmonary mycoses is poorly understood. We sequenced the internal transcribed spacer (ITS) region and D1/D2 domain of the larger subunit (LSU) of 52 NSMs isolated from respiratory specimens. The basidiomycetes were the predominant NSMs, of which
Schizophyllum commune
was the most common agent in allergic bronchopulmonary mycosis (ABPM), followed by
Ceriporia lacerata
in invasive fungal disease.
Porostereum spadiceum
,
Phanaerochaete stereoides
,
Neosartorya fischeri
, and
Marasmiellus palmivorus
were the other molds observed. Application of ITS and LSU region sequencing identified 92% of the isolates. The antifungal susceptibility data revealed that all basidiomycetes tested were susceptible to amphotericin B and resistant to caspofungin, fluconazole, and flucytosine. Except for 3 isolates of
S. commune
and a solitary isolate of
M. palmivorus
, all basidiomycetes had low MICs for itraconazole, posaconazole, and voriconazole. Basidiomycetes were isolated from patients with ABPM, invasive pulmonary mycosis/pneumonia, or fungal balls. In addition, the majority of the basidiomycetes were isolated from patients with chronic respiratory disorders who were sensitized to one of the basidiomycetous fungi and demonstrated precipitating antibodies against the incriminating fungi, indicating an indolent tissue reaction. Thus, isolation of basidiomycetes from the lower respiratory tract could be significant, and it is important to monitor these patients in order to prevent subsequent lung damage.
Combined Quantification of Pulmonary Pneumocystis jirovecii DNA and Serum (1→3)-β-
d
-Glucan for Differential Diagnosis of Pneumocystis Pneumonia and Pneumocystis Colonization
Authors: Damiani Céline , Le Gal Solène , Da Costa Cécilia , Virmaux Michèle , Nevez Gilles , Totet Anne 
Published: August 2013

ABSTRACT

This study assessed a quantitative PCR (qPCR) assay for
Pneumocystis jirovecii
quantification in bronchoalveolar lavage (BAL) fluid samples combined with serum (1→3)-β-
d
-glucan (BG) level detection to distinguish
Pneumocystis
pneumonia (PCP) from pulmonary colonization with
P. jirovecii
. Forty-six patients for whom
P. jirovecii
was initially detected in BAL fluid samples were retrospectively enrolled. Based on clinical data and results of
P. jirovecii
detection, 17 and 29 patients were diagnosed with PCP and colonization, respectively. BAL fluid samples were reassayed using a qPCR assay targeting the mitochondrial large subunit rRNA gene. qPCR results and serum BG levels (from a Fungitell kit) were analyzed conjointly.
P. jirovecii
DNA copy numbers were significantly higher in the PCP group than in the colonization group (1.3 × 10
7
versus 3.4 × 10
3
copies/μl,
P
< 0.05). A lower cutoff value (1.6 × 10
3
copies/μl) achieving 100% sensitivity for PCP diagnosis and an upper cutoff value (2 × 10
4
copies/μl) achieving 100% specificity were determined. Applying these two values, 13/17 PCP patients and 19/29 colonized patients were correctly assigned to their patient groups. For the remaining 14 patients with
P. jirovecii
DNA copy numbers between the cutoff values, PCP and colonization could not be distinguished on the basis of qPCR results. Four of these patients who were initially assigned to the PCP group presented BG levels of ≥100 pg/ml. The other 10 patients, who were initially assigned to the colonization group, presented BG levels of <100 pg/ml. These results suggest that the combination of the qPCR assay, applying cutoff values of 1.6 × 10
3
and 2 × 10
4
copies/μl, and serum BG detection, applying a 100 pg/ml threshold, can differentiate PCP and colonization diagnoses.
Glycoprotein B Cleavage Is Important for Murid Herpesvirus 4 To Infect Myeloid Cells
Authors: Glauser Daniel L. , Milho Ricardo , Frederico Bruno , May Janet S. , Kratz Anne-Sophie , Gillet Laurent , Stevenson Philip G. 
Published: August 2013

ABSTRACT

Glycoprotein B (gB) is a conserved herpesvirus virion component implicated in membrane fusion. As with many—but not all—herpesviruses, the gB of murid herpesvirus 4 (MuHV-4) is cleaved into disulfide-linked subunits, apparently by furin. Preventing gB cleavage for some herpesviruses causes minor infection deficits
in vitro
, but what the cleavage contributes to host colonization has been unclear. To address this, we mutated the furin cleavage site (R-R-K-R) of the MuHV-4 gB. Abolishing gB cleavage did not affect its expression levels, glycosylation, or antigenic conformation.
In vitro
, mutant viruses entered fibroblasts and epithelial cells normally but had a significant entry deficit in myeloid cells such as macrophages and bone marrow-derived dendritic cells. The deficit in myeloid cells was not due to reduced virion binding or endocytosis, suggesting that gB cleavage promotes infection at a postendocytic entry step, presumably viral membrane fusion.
In vivo
, viruses lacking gB cleavage showed reduced lytic spread in the lungs. Alveolar epithelial cell infection was normal, but alveolar macrophage infection was significantly reduced. Normal long-term latency in lymphoid tissue was established nonetheless.
Later Passages of Neural Progenitor Cells from Neonatal Brain Are More Permissive for Human Cytomegalovirus Infection
Authors: Pan Xing , Li Xiao-Jun , Liu Xi-Juan , Yuan Hui , Li Jia-Fu , Duan Ying-Liang , Ye Han-Qing , Fu Ya-Ru , Qiao Guan-Hua , Wu Cong-Cong , Yang Bo , Tian Xiao-Hui , Hu Kang-Hong , Miao Ling-Feng , Chen Xiao-Ling , Zheng Jun , Rayner Simon , Schwartz Philip H. , Britt William J. , Xu Jiang , Luo Min-Hua 
Published: August 2013

ABSTRACTCongenital human cytomegalovirus (HCMV) infection is the most frequent infectious cause of birth defects, primarily neurological disorders. Neural progenitor/stem cells (NPCs) are the major cell type in the subventricular zone and are susceptible to HCMV infection. In culture, the differentiation status of NPCs may change with passage, which in turn may alter susceptibility to virus infection. Previously, only early-passage (i.e., prior to passage 9) NPCs were studied and shown to be permissive to HCMV infection. In this study, NPC cultures derived at different gestational ages were evaluated after short (passages 3 to 6) and extended (passages 11 to 20)in vitropassages for biological and virological parameters (i.e., cell morphology, expression of NPC markers and HCMV receptors, viral entry efficiency, viral gene expression, virus-induced cytopathic effect, and release of infectious progeny). These parameters were not significantly influenced by the gestational age of the source tissues. However, extended-passage cultures showed evidence of initiation of differentiation, increased viral entry, and more efficient production of infectious progeny. These results confirm that NPCs are fully permissive for HCMV infection and that extended-passage NPCs initiate differentiation and are more permissive for HCMV infection. Later-passage NPCs being differentiated and more permissive for HCMV infection suggest that HCMV infection in fetal brain may cause more neural cell loss and give rise to severe neurological disabilities with advancing brain development.
Human Cytomegalovirus IE1 Protein Disrupts Interleukin-6 Signaling by Sequestering STAT3 in the Nucleus
Authors: Reitsma Justin M. , Sato Hiromi , Nevels Michael , Terhune Scott S. , Paulus Christina 
Published: August 2013

ABSTRACTIn the canonical STAT3 signaling pathway, binding of agonist to receptors activates Janus kinases that phosphorylate cytoplasmic STAT3 at tyrosine 705 (Y705). Phosphorylated STAT3 dimers accumulate in the nucleus and drive the expression of genes involved in inflammation, angiogenesis, invasion, and proliferation. Here, we demonstrate that human cytomegalovirus (HCMV) infection rapidly promotes nuclear localization of STAT3 in the absence of robust phosphorylation at Y705. Furthermore, infection disrupts interleukin-6 (IL-6)-induced phosphorylation of STAT3 and expression of a subset of IL-6-induced STAT3-regulated genes, including SOCS3. We show that the HCMV 72-kDa immediate-early 1 (IE1) protein associates with STAT3 and is necessary to localize STAT3 to the nucleus during infection. Furthermore, expression of IE1 is sufficient to disrupt IL-6-induced phosphorylation of STAT3, binding of STAT3 to the SOCS3 promoter, and SOCS3 gene expression. Finally, inhibition of STAT3 nuclear localization or STAT3 expression during infection is linked to diminished HCMV genome replication. Viral gene expression is also disrupted, with the greatest impact seen following viral DNA synthesis. Our study identifies IE1 as a new regulator of STAT3 intracellular localization and IL-6 signaling and points to an unanticipated role of STAT3 in HCMV infection.