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Sample records for abnormally high flow

  1. Abnormal high surface heat flow caused by the Emeishan mantle plume

    NASA Astrophysics Data System (ADS)

    Jiang, Qiang; Qiu, Nansheng; Zhu, Chuanqing

    2016-04-01

    It is commonly believed that increase of heat flow caused by a mantle plume is small and transient. Seafloor heat flow data near the Hawaiian hotspot and the Iceland are comparable to that for oceanic lithosphere elsewhere. Numerical modeling of the thermal effect of the Parana large igneous province shows that the added heat flow at the surface caused by the magmatic underplating is less than 5mW/m2. However, the thermal effect of Emeishan mantle plume (EMP) may cause the surface hear-flow abnormally high. The Middle-Late Emeishan mantle plume is located in the western Yangtze Craton. The Sichuan basin, to the northeast of the EMP, is a superimposed basin composed of Paleozoic marine carbonate rocks and Mesozoic-Cenozoic terrestrial clastic rocks. The vitrinite reflectance (Ro) data as a paleogeothermal indicator records an apparent change of thermal regime of the Sichuan basin. The Ro profiles from boreholes and outcrops which are close to the center of the basalt province exhibit a 'dog-leg' style at the unconformity between the Middle and Upper Permian, and they show significantly higher gradients in the lower subsection (pre-Middle Permian) than the Upper subsection (Upper Permian to Mesozoic). Thermal history inversion based on these Ro data shows that the lower subsection experienced a heat flow peak much higher than that of the upper subsection. The abnormal heat flow in the Sichuan basin is consistent with the EMP in temporal and spatial distribution. The high-temperature magmas from deep mantle brought heat to the base of the lithosphere, and then large amount of heat was conducted upwards, resulting in the abnormal high surface heat flow.

  2. Abnormally high formation pressures, Potwar Plateau, Pakistan

    USGS Publications Warehouse

    Law, B.E.; Shah, S.H.A.; Malik, M.A.

    1998-01-01

    Abnormally high formation pressures in the Potwar Plateau of north-central Pakistan are major obstacles to oil and gas exploration. Severe drilling problems associated with high pressures have, in some cases, prevented adequate evaluation of reservoirs and significantly increased drilling costs. Previous investigations of abnormal pressure in the Potwar Plateau have only identified abnormal pressures in Neogene rocks. We have identified two distinct pressure regimes in this Himalayan foreland fold and thrust belt basin: one in Neogene rocks and another in pre-Neogene rocks. Pore pressures in Neogene rocks are as high as lithostatic and are interpreted to be due to tectonic compression and compaction disequilibrium associated with high rates of sedimentation. Pore pressure gradients in pre-Neogene rocks are generally less than those in Neogene rocks, commonly ranging from 0.5 to 0.7 psi/ft (11.3 to 15.8 kPa/m) and are most likely due to a combination of tectonic compression and hydrocarbon generation. The top of abnormally high pressure is highly variable and doesn't appear to be related to any specific lithologic seal. Consequently, attempts to predict the depth to the top of overpressure prior to drilling are precluded.

  3. Detection of abnormal events via optical flow feature analysis.

    PubMed

    Wang, Tian; Snoussi, Hichem

    2015-03-24

    In this paper, a novel algorithm is proposed to detect abnormal events in video streams. The algorithm is based on the histogram of the optical flow orientation descriptor and the classification method. The details of the histogram of the optical flow orientation descriptor are illustrated for describing movement information of the global video frame or foreground frame. By combining one-class support vector machine and kernel principal component analysis methods, the abnormal events in the current frame can be detected after a learning period characterizing normal behaviors. The difference abnormal detection results are analyzed and explained. The proposed detection method is tested on benchmark datasets, then the experimental results show the effectiveness of the algorithm.

  4. Detection of Abnormal Events via Optical Flow Feature Analysis

    PubMed Central

    Wang, Tian; Snoussi, Hichem

    2015-01-01

    In this paper, a novel algorithm is proposed to detect abnormal events in video streams. The algorithm is based on the histogram of the optical flow orientation descriptor and the classification method. The details of the histogram of the optical flow orientation descriptor are illustrated for describing movement information of the global video frame or foreground frame. By combining one-class support vector machine and kernel principal component analysis methods, the abnormal events in the current frame can be detected after a learning period characterizing normal behaviors. The difference abnormal detection results are analyzed and explained. The proposed detection method is tested on benchmark datasets, then the experimental results show the effectiveness of the algorithm. PMID:25811227

  5. Viscous Energy Loss in the Presence of Abnormal Aortic Flow

    PubMed Central

    Barker, A.J.; van Ooij, P.; Bandi, K.; Garcia, J.; Albaghdadi, M.; McCarthy, P.; Bonow, R. O.; Carr, J.; Collins, J.; Malaisrie, C.; Markl, M.

    2014-01-01

    Purpose To present a theoretical basis for noninvasively characterizing in vivo fluid-mechanical energy losses, and to apply it in a pilot study of patients known to express abnormal aortic flow patterns. Methods 4D flow MRI was used to characterize laminar viscous energy losses in the aorta of normal controls (n=12, age=37±10), patients with aortic dilation (n=16, age=52±8), and patients with aortic valve stenosis matched for age and aortic size (n=14, age=46±15), using a relationship between the 3D velocity field and viscous energy dissipation. Results Viscous energy loss was significantly elevated in the thoracic aorta for patients with dilated aorta (3.6±1.3 mW, p=0.024) and patients with aortic stenosis (14.3±8.2 mW, p<0.001) compared to healthy volunteers (2.3±0.9 mW). The same pattern of significant differences were seen in the ascending aorta, where viscous energy losses in patients with dilated aortas (2.2±1.1 mW, p=0.021) and patients with aortic stenosis (10.9±6.8 mW, p<0.001) were elevated compared to healthy volunteers (1.2±0.6 mW). Conclusion This technique provides a capability to quantify the contribution of abnormal laminar blood flow to increased ventricular afterload. In this pilot study, viscous energy loss in patient cohorts was significantly elevated and indicates that cardiac afterload is increased due to abnormal flow. PMID:24122967

  6. Abnormal high density lipoproteins in cerebrotendinous xanthomatosis

    SciTech Connect

    Shore, V.; Salen, G.; Cheng, F.W.; Forte, T.; Shefer, S.; Tint, G.S.

    1981-11-01

    The plasma lipoprotein profiles and high density lipoproteins (HDL) were characterized in patients with the genetic disease cerebrotendinous xanthomatosis (CTX). The mean HDL-cholesterol concentration in the CTX plasmas was 14.5 +/- 3.2 mg/dl, about one-third the normal value. The low HDL-cholesterol reflects a low concentration and an abnormal lipid composition of the plasma HDL. Relative to normal HDL, the cholesteryl esters are low, free cholesterol and phospholipids essentially normal, and triglycerides increased. The ratio of apoprotein (apo) to total cholesterol in the HDL of CTX was two to three times greater than normal. In the CTX HDL, the ratio of apoAI to apoAII was high, the proportion of apoC low, and a normally minor form of apoAI increased relative to other forms. The HDL in electron micrographs appeared normal morphologically and in particle size. The adnormalities in lipoprotein distribution profiles and composition of the plasma HDL result from metabolic defects that are not understood but may be linked to the genetic defect in bile acid synthesis in CTX. As a consequence, it is probable that the normal functions of the HDL, possibly including modulation of LDL-cholesterol uptake and the removal of excess cholesterol from peripheral tissues, are perturbed significantly in this disease.

  7. Detector for flow abnormalities in gaseous diffusion plant compressors

    DOEpatents

    Smith, Stephen F.; Castleberry, Kim N.

    1998-01-01

    A detector detects a flow abnormality in a plant compressor which outputs a motor current signal. The detector includes a demodulator/lowpass filter demodulating and filtering the motor current signal producing a demodulated signal, and first, second, third and fourth bandpass filters connected to the demodulator/lowpass filter, and filtering the demodulated signal in accordance with first, second, third and fourth bandpass frequencies generating first, second, third and fourth filtered signals having first, second, third and fourth amplitudes. The detector also includes first, second, third and fourth amplitude detectors connected to the first, second, third and fourth bandpass filters respectively, and detecting the first, second, third and fourth amplitudes, and first and second adders connected to the first and fourth amplitude detectors and the second and third amplitude detectors respectively, and adding the first and fourth amplitudes and the second and third amplitudes respectively generating first and second added signals. Finally, the detector includes a comparator, connected to the first and second adders, and comparing the first and second added signals and detecting the abnormal condition in the plant compressor when the second added signal exceeds the first added signal by a predetermined value.

  8. Detector for flow abnormalities in gaseous diffusion plant compressors

    DOEpatents

    Smith, S.F.; Castleberry, K.N.

    1998-06-16

    A detector detects a flow abnormality in a plant compressor which outputs a motor current signal. The detector includes a demodulator/lowpass filter demodulating and filtering the motor current signal producing a demodulated signal, and first, second, third and fourth bandpass filters connected to the demodulator/lowpass filter, and filtering the demodulated signal in accordance with first, second, third and fourth bandpass frequencies generating first, second, third and fourth filtered signals having first, second, third and fourth amplitudes. The detector also includes first, second, third and fourth amplitude detectors connected to the first, second, third and fourth bandpass filters respectively, and detecting the first, second, third and fourth amplitudes, and first and second adders connected to the first and fourth amplitude detectors and the second and third amplitude detectors respectively, and adding the first and fourth amplitudes and the second and third amplitudes respectively generating first and second added signals. Finally, the detector includes a comparator, connected to the first and second adders, and comparing the first and second added signals and detecting the abnormal condition in the plant compressor when the second added signal exceeds the first added signal by a predetermined value. 6 figs.

  9. Regional cerebral blood flow abnormalities in Alzheimer's Disease

    SciTech Connect

    Rezai, K.; Damasio, H.; Graff-Radford, N.; Eslinger, P.; Kirchner, P.

    1985-05-01

    In 37 patients (ages 58-81) with senile dementia of Alzheimer type (SDAT), regional cerebral blood flow (rCBF) was studied utilizing a dedicated SPECT system (Tomomatic-64) that produces rCBF images from 4-minute clearance of Xenon-133 in the brain. The authors have modified the device to acquire 5 continuous tomographic slices simultaneously. A consistent pattern of diminished blood flow was seen in 33 patients in the posterior-temporal and lower-parietal brain regions. Computer programs were developed to quantitate the size of the affected brain tissue in the posterolateral brain areas (confined to the posterior 40% and the lateral 25% of the major and minor brain axes respectively). They have previously reported normal rCBF in 25 volunteers to be greater than 45 ml/min/100g with less than 10% regional variation. Hence, an area was considered abnormal if rCBF measured less than 40 ml/min/100g or was less than 70% of the mean rCBF value in the anterior temporal-frontal regions.

  10. Abnormalities in the flow-volume loop in obstructive sleep apnoea sitting and supine.

    PubMed Central

    Shore, E T; Millman, R P

    1984-01-01

    We evaluated the effect of posture on the sensitivity and specificity of abnormalities in the flow-volume loop in 30 patients with suspected obstructive sleep apnoea. Flow-volume loops were judged as abnormal if the FEF50/FIF50 ratio was greater than 1 or if the sawtooth sign was judged to be present by at least two of three chest physicians. Detailed nocturnal recordings confirmed the presence of obstructive sleep apnoea in 17 of the 30 patients. Our results showed that both the sensitivity and the specificity of each of the flow-volume criteria for the diagnosis of obstructive sleep apnoea were higher when the loops were recorded in the supine than when they were recorded in the sitting position. The sensitivities were low, however, even with the supine posture--sawtoothing 41% and FEF50/FIF50 ratio greater than 1 47%. The highest sensitivity (71%) was obtained by considering a positive result as being the presence of either of the abnormalities in either the sitting or the supine posture. This sensitivity of the flow-volume loop was too low to recommend it as a routine screening test for the diagnosis of obstructive sleep apnoea but the presence of the sawtooth sign had a high specificity (92%) for the diagnosis of obstructive sleep apnoea. Furthermore, there was a greater fall in oxygen saturation in patients with apnoea who had sawtoothing than in those without sawtoothing. The presence of the sawtooth sign should increase the suspicion of sleep apnoea and suggest the need for further investigation. The effect of posture on the occurrence of abnormalities in the flow-volume loop suggests that position alters the configuration of the upper airway. PMID:6495246

  11. Investigation of Abnormal Heat Transfer and Flow in a VHTR Reactor Core

    SciTech Connect

    Kawaji, Masahiro; Valentin, Francisco I.; Artoun, Narbeh; Banerjee, Sanjoy; Sohal, Manohar; Schultz, Richard; McEligot, Donald M.

    2015-12-21

    The main objective of this project was to identify and characterize the conditions under which abnormal heat transfer phenomena would occur in a Very High Temperature Reactor (VHTR) with a prismatic core. High pressure/high temperature experiments have been conducted to obtain data that could be used for validation of VHTR design and safety analysis codes. The focus of these experiments was on the generation of benchmark data for design and off-design heat transfer for forced, mixed and natural circulation in a VHTR core. In particular, a flow laminarization phenomenon was intensely investigated since it could give rise to hot spots in the VHTR core.

  12. Cerebral blood flow in normal and abnormal sleep and dreaming

    SciTech Connect

    Meyer, J.S.; Ishikawa, Y.; Hata, T.; Karacan, I.

    1987-07-01

    Measurements of regional or local cerebral blood flow (CBF) by the xenon-133 inhalation method and stable xenon computerized tomography CBF (CTCBF) method were made during relaxed wakefulness and different stages of REM and non-REM sleep in normal age-matched volunteers, narcoleptics, and sleep apneics. In the awake state, CBF values were reduced in both narcoleptics and sleep apneics in the brainstem and cerebellar regions. During sleep onset, whether REM or stage I-II, CBF values were paradoxically increased in narcoleptics but decreased severely in sleep apneics, while in normal volunteers they became diffusely but more moderately decreased. In REM sleep and dreaming CBF values greatly increased, particularly in right temporo-parietal regions in subjects experiencing both visual and auditory dreaming.

  13. High Speed Vortex Flows

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Wilcox, Floyd J., Jr.; Bauer, Steven X. S.; Allen, Jerry M.

    2000-01-01

    A review of the research conducted at the National Aeronautics and Space Administration (NASA), Langley Research Center (LaRC) into high-speed vortex flows during the 1970s, 1980s, and 1990s is presented. The data reviewed is for flat plates, cavities, bodies, missiles, wings, and aircraft. These data are presented and discussed relative to the design of future vehicles. Also presented is a brief historical review of the extensive body of high-speed vortex flow research from the 1940s to the present in order to provide perspective of the NASA LaRC's high-speed research results. Data are presented which show the types of vortex structures which occur at supersonic speeds and the impact of these flow structures to vehicle performance and control is discussed. The data presented shows the presence of both small- and large scale vortex structures for a variety of vehicles, from missiles to transports. For cavities, the data show very complex multiple vortex structures exist at all combinations of cavity depth to length ratios and Mach number. The data for missiles show the existence of very strong interference effects between body and/or fin vortices and the downstream fins. It was shown that these vortex flow interference effects could be both positive and negative. Data are shown which highlights the effect that leading-edge sweep, leading-edge bluntness, wing thickness, location of maximum thickness, and camber has on the aerodynamics of and flow over delta wings. The observed flow fields for delta wings (i.e. separation bubble, classical vortex, vortex with shock, etc.) are discussed in the context of' aircraft design. And data have been shown that indicate that aerodynamic performance improvements are available by considering vortex flows as a primary design feature. Finally a discussing of a design approach for wings which utilize vortex flows for improved aerodynamic performance at supersonic speed is presented.

  14. [High frequency of thyroid abnormalities in polycystic ovary syndrome].

    PubMed

    Calvar, Cecilia E; Bengolea, Sonia V; Deutsch, Susana I; Hermes, Ricardo; Ramos, Gustavo; Loyato, Marcelo

    2015-01-01

    The prevalence of thyroid abnormalities (TA) has not been sufficiently assessed in polycystic ovary syndrome (PCOS). Our aim was to evaluate this relationship. In this prospective study 194 women were included. The PCOS group consisted of 142 patients (diagnosed by Rotterdam 2003 criteria) and the control group included 52 age-matched healthy women. Fasting blood samples were drawn for free T4, thyrotropin, thyroperoxidase antibodies (TPOAb), fasting insulin, glucose and HOMA-IR were calculated. A total of 52 PCOS patients had either autoimmune thyroiditis (AIT+) and/or subclinical hypothyroidism (HSC) (36.6%) (thyroid abnormalities:TA+) compared with 7 women of the control group (13.5%), accounting for more than a five fold higher prevalence of TA in PCOS patients, compared with the age-matched controls (adjusted odds ratio: 5.6; CI 95%: 2.1 -14.9; p<0.001). TA+ patients had significantly higher FI and HOMA-IR values than patients without thyroid abnormalities (p<0.05). These results demonstrate a high rate of TA in young PCOS women, associated with higher levels of FI and HOMA-IR. As PCOS, hypothyroidism and thyroid autoimmunity may have a profound impact on reproductive health, our data indicate that PCOS patients should be screened for TA. PMID:26339875

  15. Extended 3D Approach for Quantification of Abnormal Ascending Aortic Flow

    PubMed Central

    Sigovan, Monica; Dyverfeldt, Petter; Wrenn, Jarrett; Tseng, Elaine E.; Saloner, David; Hope, Michael D.

    2015-01-01

    Background Flow displacement quantifies eccentric flow, a potential risk factor for aneurysms in the ascending aorta, but only at a single anatomic location. The aim of this study is to extend flow displacement analysis to 3D in patients with aortic and aortic valve pathologies. Methods 43 individuals were studied with 4DFlow MRI in 6 groups: healthy, tricuspid aortic valve (TAV) with aortic stenosis (AS) but no dilatation, TAV with dilatation but no AS, and TAV with both AS and dilatation, BAV without AS or dilatation, BAV without AS but with dilation. The protocol was approved by our institutional review board, and informed consent was obtained. Flow displacement was calculated for multiple planes along the ascending aorta, and 2D and 3D analyses were compared. Results Good correlation was found between 2D flow displacement and both maximum and average 3D values (r>0.8). Healthy controls had significantly lower flow displacement values with all approaches (p<0.05). The highest flow displacement was seen with stenotic TAV and aortic dilation (0.24±0.02 with maximum flow displacement). The 2D approach underestimated the maximum flow displacement by more than 20% in 13 out of 36 patients (36%). Conclusions The extended 3D flow displacement analysis offers a more comprehensive quantitative evaluation of abnormal systolic flow in the ascending aorta than 2D analysis. Differences between patient subgroups are better demonstrated, and maximum flow displacement is more reliable assessed. PMID:25721998

  16. High Prevalence of Prothrombotic Abnormalities in Multifocal Osteonecrosis

    PubMed Central

    Peris, Pilar; Reverter, Joan Carles; Espinosa, Gerard; Martinez-Ferrer, Angeles; Monegal, Ana; Monteagudo, Juan; Tàssies, Dolors; Guañabens, Nuria

    2013-01-01

    Abstract Multifocal or multiple osteonecrosis (ON), defined by the involvement of 3 or more anatomic sites, is unusual, being observed in only 3%–10% of patients diagnosed with ON. We report the clinical characteristics of a cohort of 29 patients with multifocal ON from a single center and evaluate the prevalence of associated prothrombotic abnormalities in 26 of these patients. We conducted a retrospective study of all patients diagnosed with multifocal ON evaluated in our institution during the last 20 years. We recorded clinical manifestations and underlying diagnoses. A wide thrombophilic profile was performed, including antithrombin, protein C, protein S, lupus anticoagulant, anticardiolipin antibodies, activated protein C resistance, factor V Leiden, mutation G-20210-A of the prothrombin gene, and factor VIII. Coagulation test results were compared with those in a healthy control group and a group of patients with history of lower-extremity deep venous thrombosis. The mean age of the patients was 49.2 ± 15 years (range, 28–81 yr). The mean number of ON localizations per patient was 5.2 ± 2.3 (range, 3–11). Hips were the most commonly affected joint (82%), followed by knees (58%), shoulders (37%), and ankles (13%). Most patients had an underlying disease process, and 12 of 25 (48%) patients had coagulation test abnormalities. The most common alterations were high factor VIII levels and antiphospholipid antibody (aPL) positivity in 24% and 20% of cases, respectively. These abnormalities were more prevalent in patients with multifocal ON compared with patients in the control groups. Sixty-one percent of patients had a history of corticosteroid treatment. Patients with coagulation abnormalities had a higher number of ON localizations per patient (6.5 ± 2.7 vs. 3.88 ± 0.8; p = 0.002) and a higher prevalence of atypical ON localizations (25% vs. 0%; p = 0.05). In conclusion, in the present cohort of patients with multifocal ON, 48% of the patients had at

  17. 14 CFR 91.144 - Temporary restriction on flight operations during abnormally high barometric pressure conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... during abnormally high barometric pressure conditions. 91.144 Section 91.144 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL... flight operations during abnormally high barometric pressure conditions. (a) Special flight...

  18. Cerebrospinal fluid flow abnormalities in patients with neoplastic meningitis. An evaluation using /sup 111/In-DTPA ventriculography

    SciTech Connect

    Grossman, S.A.; Trump, D.L.; Chen, D.C.; Thompson, G.; Camargo, E.E.

    1982-11-01

    Cerebrospinal fluid flow dynamics were evaluated by /sup 111/In-diethylenetriamine pentaacetic acid (/sup 111/In-DTPA) ventriculography in 27 patients with neoplastic meningitis. Nineteen patients (70 percent) had evidence of cerebrospinal fluid flow disturbances. These occurred as ventricular outlet obstructions, abnormalities of flow in the spinal canal, or flow distrubances over the cortical convexities. Tumor histology, physical examination, cerebrospinal fluid analysis, myelograms, and computerized axial tomographic scans were not sufficient to predict cerebrospinal fluid flow patterns. These data indicate that cerebrospinal fluid flow abnormalities are common in patients with neoplastic meningitis and that /sup 111/In-DTPA cerebrospinal fluid flow imaging is useful in characterizing these abnormalities. This technique provides insight into the distribution of intraventricularly administered chemotherapy and may provide explanations for treatment failure and drug-induced neurotoxicity in patients with neoplastic meningitis.

  19. Abnormal elastic and vibrational behaviors of magnetite at high pressures.

    PubMed

    Lin, Jung-Fu; Wu, Junjie; Zhu, Jie; Mao, Zhu; Said, Ayman H; Leu, Bogdan M; Cheng, Jinguang; Uwatoko, Yoshiya; Jin, Changqing; Zhou, Jianshi

    2014-01-01

    Magnetite exhibits unique electronic, magnetic, and structural properties in extreme conditions that are of great research interest. Previous studies have suggested a number of transitional models, although the nature of magnetite at high pressure remains elusive. We have studied a highly stoichiometric magnetite using inelastic X-ray scattering, X-ray diffraction and emission, and Raman spectroscopies in diamond anvil cells up to ~20 GPa, while complementary electrical conductivity measurements were conducted in a cubic anvil cell up to 8.5 GPa. We have observed an elastic softening in the diagonal elastic constants (C11 and C44) and a hardening in the off-diagonal constant (C12) at ~8 GPa where significant elastic anisotropies in longitudinal and transverse acoustic waves occur, especially along the [110] direction. An additional vibrational Raman band between the A1g and T2g modes was also detected at the transition pressure. These abnormal elastic and vibrational behaviors of magnetite are attributed to the occurrence of the octahedrally-coordinated Fe(2+)-Fe(3+)-Fe(2+) ions charge-ordering along the [110] direction in the inverse spinel structure. We propose a new phase diagram of magnetite in which the temperature for the metal-insulator and distorted structural transitions decreases with increasing pressure while the charge-ordering transition occurs at ~8 GPa and room temperature. PMID:25186916

  20. Abnormal Elastic and Vibrational Behaviors of Magnetite at High Pressures

    PubMed Central

    Lin, Jung-Fu; Wu, Junjie; Zhu, Jie; Mao, Zhu; Said, Ayman H.; Leu, Bogdan M.; Cheng, Jinguang; Uwatoko, Yoshiya; Jin, Changqing; Zhou, Jianshi

    2014-01-01

    Magnetite exhibits unique electronic, magnetic, and structural properties in extreme conditions that are of great research interest. Previous studies have suggested a number of transitional models, although the nature of magnetite at high pressure remains elusive. We have studied a highly stoichiometric magnetite using inelastic X-ray scattering, X-ray diffraction and emission, and Raman spectroscopies in diamond anvil cells up to ~20 GPa, while complementary electrical conductivity measurements were conducted in a cubic anvil cell up to 8.5 GPa. We have observed an elastic softening in the diagonal elastic constants (C11 and C44) and a hardening in the off-diagonal constant (C12) at ~8 GPa where significant elastic anisotropies in longitudinal and transverse acoustic waves occur, especially along the [110] direction. An additional vibrational Raman band between the A1g and T2g modes was also detected at the transition pressure. These abnormal elastic and vibrational behaviors of magnetite are attributed to the occurrence of the octahedrally-coordinated Fe2+-Fe3+-Fe2+ ions charge-ordering along the [110] direction in the inverse spinel structure. We propose a new phase diagram of magnetite in which the temperature for the metal-insulator and distorted structural transitions decreases with increasing pressure while the charge-ordering transition occurs at ~8 GPa and room temperature. PMID:25186916

  1. High prevalence of thyroid ultrasonographic abnormalities in primary aldosteronism.

    PubMed

    Armanini, Decio; Nacamulli, Davide; Scaroni, Carla; Lumachi, Franco; Selice, Riccardo; Fiore, Cristina; Favia, Gennaro; Mantero, Franco

    2003-11-01

    The study was performed to evaluate the prevalence of thyroid abnormalities detected by ultrasonography and, in particular, of multinodular nontoxic goiter in primary aldosteronism. We analyzed 80 consecutive of patients with primary hyperaldosteronism (40 with unilateral adenoma and 40 with idiopathic hyperaldosteronism) and 80 normotensive healthy controls, comparable for age, sex, iodine intake, and geographical area. Blood pressure, thyroid palpation, thyroid function, and ultrasonography were evaluated. The prevalence of ultrasonographic thyroid abnormalities was 60% in primary aldosteronism and 27% in controls (p < 0.0001). There was a statistically significant difference in prevalence of these abnormalities in unilateral adenoma and idiopathic hyperaldosteronism with respect to controls (p < 0.05 and p < 0.0001, respectively). The prevalence of multinodular nontoxic goiter in idiopathic hyperaldosteronism was higher than in controls (p < 0.001) and, in particular, in female patients. From these data it seems to be worth considering the existence of primary hyperaldosteronism in patients with multinodular goiter and hypertension. PMID:14665720

  2. Characterization of abnormal wall shear stress using 4D flow MRI in human bicuspid aortopathy

    PubMed Central

    van Ooij, Pim; Potters, Wouter V.; Collins, Jeremy; Carr, Maria; Carr, James; Malaisrie, S. Chris; Fedak, Paul W.M.; McCarthy, Patrick M.; Markl, Michael; Barker, Alex J.

    2014-01-01

    There exists considerable controversy surrounding the timing and extent of aortic resection for patients with BAV disease. Since abnormal wall shear stress (WSS) is potentially associated with tissue remodeling in BAV-related aortopathy, we propose a methodology that creates patient-specific ‘heat maps’ of abnormal WSS, based on 4D flow MRI. The heat maps were created by detecting outlier measurements from a volumetric 3D map of ensemble-averaged WSS in healthy controls. 4D flow MRI was performed in 13 BAV patients, referred for aortic resection and 10 age-matched controls. Systolic WSS was calculated from this data, and an ensemble-average and standard deviation (SD) WSS map of the controls was created. Regions of the individual WSS maps of the BAV patients that showed a higher WSS than the mean+1.96SD of the ensemble-average control WSS map were highlighted. Elevated WSS was found on the greater ascending aorta (35% ± 15 of the surface area), which correlated significantly with peak systolic velocity (R2=0.5, P=0.01) and showed good agreement with the resected aortic regions. This novel approach to characterize regional aortic WSS may allow clinicians to gain unique insights regarding the heterogeneous expression of aortopathy and may be leveraged to guide patient-specific resection strategies for aorta repair. PMID:25118671

  3. Characterization of abnormal wall shear stress using 4D flow MRI in human bicuspid aortopathy.

    PubMed

    van Ooij, Pim; Potters, Wouter V; Collins, Jeremy; Carr, Maria; Carr, James; Malaisrie, S Chris; Fedak, Paul W M; McCarthy, Patrick M; Markl, Michael; Barker, Alex J

    2015-06-01

    There exists considerable controversy surrounding the timing and extent of aortic resection for patients with BAV disease. Since abnormal wall shear stress (WSS) is potentially associated with tissue remodeling in BAV-related aortopathy, we propose a methodology that creates patient-specific 'heat maps' of abnormal WSS, based on 4D flow MRI. The heat maps were created by detecting outlier measurements from a volumetric 3D map of ensemble-averaged WSS in healthy controls. 4D flow MRI was performed in 13 BAV patients, referred for aortic resection and 10 age-matched controls. Systolic WSS was calculated from this data, and an ensemble-average and standard deviation (SD) WSS map of the controls was created. Regions of the individual WSS maps of the BAV patients that showed a higher WSS than the mean + 1.96SD of the ensemble-average control WSS map were highlighted. Elevated WSS was found on the greater ascending aorta (35% ± 15 of the surface area), which correlated significantly with peak systolic velocity (R (2) = 0.5, p = 0.01) and showed good agreement with the resected aortic regions. This novel approach to characterize regional aortic WSS may allow clinicians to gain unique insights regarding the heterogeneous expression of aortopathy and may be leveraged to guide patient-specific resection strategies for aorta repair. PMID:25118671

  4. 14 CFR 91.144 - Temporary restriction on flight operations during abnormally high barometric pressure conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... during abnormally high barometric pressure conditions. 91.144 Section 91.144 Aeronautics and Space... flight operations during abnormally high barometric pressure conditions. (a) Special flight restrictions. When any information indicates that barometric pressure on the route of flight currently exceeds...

  5. 14 CFR 91.144 - Temporary restriction on flight operations during abnormally high barometric pressure conditions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... during abnormally high barometric pressure conditions. 91.144 Section 91.144 Aeronautics and Space... flight operations during abnormally high barometric pressure conditions. (a) Special flight restrictions. When any information indicates that barometric pressure on the route of flight currently exceeds...

  6. 14 CFR 91.144 - Temporary restriction on flight operations during abnormally high barometric pressure conditions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... during abnormally high barometric pressure conditions. 91.144 Section 91.144 Aeronautics and Space... flight operations during abnormally high barometric pressure conditions. (a) Special flight restrictions. When any information indicates that barometric pressure on the route of flight currently exceeds...

  7. 14 CFR 91.144 - Temporary restriction on flight operations during abnormally high barometric pressure conditions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... during abnormally high barometric pressure conditions. 91.144 Section 91.144 Aeronautics and Space... flight operations during abnormally high barometric pressure conditions. (a) Special flight restrictions. When any information indicates that barometric pressure on the route of flight currently exceeds...

  8. Grain Flow at High Stresses

    NASA Astrophysics Data System (ADS)

    McSaveney, M. J.

    2015-12-01

    The transport mechanism of rapid long-runout rock avalanches was a hotly debated topic when I came on the scene in 1967. So how come it is still debated today? My explanation is that it is the expected outcome of peer review, poor comprehension, and technological advances outpacing intellectual advances. Why think about the problem when we can model it! So let us think about the problem. Shreve thought that rock avalanches fell upon and trapped a layer of air. What physics was he thinking about? It is how feathers and tissue papers fall. When my rock avalanches fly, they fly like unlubricated bricks using the physics of projectiles and ballistics. But the main transport mechanism is not flight. The dominant impression from watching a rock avalanche in motion is of fluid flow, as Heim described it in 1882. A rock avalanche is a very large grain flow. Bagnold studied dispersive grain flows, but why should one assume that rock avalanches are dispersive grain flows as many do. The more common grain flow type is a dense grain flow and rock avalanches are dense grain flows in which the weight can and does generate very high stresses at grain contacts. Brittle rock deforms elastically up to its compressive strength, whereupon it breaks, releasing elastic strain as transient elastic strain (seismic energy to a seismologist, acoustic energy to a physicist). Melosh and others have shown that acoustic energy can fluidize a grain mass. There is no exotic physics behind grain flow at high stress. When grains break, the released elastic strain has to go somewhere, and it goes somewhere principally by transmission though grain contacts. Depending on the state of stress at the grain contact, the contact will pass the stress or will slip at conventional values of Coulomb friction. Enough thinking! A physical model of the entire process is too big for any laboratory. So whose numerical model will do it?

  9. High gas flow alpha detector

    DOEpatents

    Bolton, Richard D.; Bounds, John A.; Rawool-Sullivan, Mohini W.

    1996-01-01

    An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors.

  10. High gas flow alpha detector

    DOEpatents

    Bolton, R.D.; Bounds, J.A.; Rawool-Sullivan, M.W.

    1996-05-07

    An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors. 4 figs.

  11. High Interstitial Fluid Pressure Is Associated with Tumor-Line Specific Vascular Abnormalities in Human Melanoma Xenografts

    PubMed Central

    Simonsen, Trude G.; Gaustad, Jon-Vidar; Leinaas, Marit N.; Rofstad, Einar K.

    2012-01-01

    Purpose Interstitial fluid pressure (IFP) is highly elevated in many solid tumors. High IFP has been associated with low radiocurability and high metastatic frequency in human melanoma xenografts and with poor survival after radiation therapy in cervical cancer patients. Abnormalities in tumor vascular networks have been identified as an important cause of elevated tumor IFP. The aim of this study was to investigate the relationship between tumor IFP and the functional and morphological properties of tumor vascular networks. Materials and Methods A-07-GFP and R-18-GFP human melanomas growing in dorsal window chambers in BALB/c nu/nu mice were used as preclinical tumor models. Functional and morphological parameters of the vascular network were assessed from first-pass imaging movies and vascular maps recorded after intravenous bolus injection of 155-kDa tetramethylrhodamine isothiocyanate-labeled dextran. IFP was measured in the center of the tumors using a Millar catheter. Angiogenic profiles of A-07-GFP and R-18-GFP cells were obtained with a quantitative PCR array. Results High IFP was associated with low growth rate and low vascular density in A-07-GFP tumors, and with high growth rate and high vascular density in R-18-GFP tumors. A-07-GFP tumors showed chaotic and highly disorganized vascular networks, while R-18-GFP tumors showed more organized vascular networks with supplying arterioles in the tumor center and draining venules in the tumor periphery. Furthermore, A-07-GFP and R-18-GFP cells differed substantially in angiogenic profiles. A-07-GFP tumors with high IFP showed high geometric resistance to blood flow due to high vessel tortuosity. R-18-GFP tumors with high IFP showed high geometric resistance to blood flow due to a large number of narrow tumor capillaries. Conclusions High IFP in A-07-GFP and R-18-GFP human melanoma xenografts was primarily a consequence of high blood flow resistance caused by tumor-line specific vascular abnormalities. PMID

  12. Management of non-high-density lipoprotein abnormalities.

    PubMed

    Rosenson, Robert S

    2009-12-01

    Epidemiological evidence supports the use of non-high-density lipoprotein cholesterol (non-HDL-C), apolipoprotein B-100 (apoB), and low-density lipoprotein particles as markers of atherogenic risk. Treatment guidelines also identify these as additional targets of lipid-modifying intervention in patients with elevated triglycerides (TG). Even when TG are only moderately elevated, many patients on statin monotherapy who have achieved targets for low-density lipoprotein cholesterol (LDL-C) fail to reach non-HDL-C treatment goals, and even fewer reach apoB goals. Combination lipid-modifying therapy is therefore indicated for comprehensive lipid management, particularly in patients with type 2 diabetes and metabolic syndrome in whom LDL-C levels are often considered 'optimal'. Of the available options, adding either a niacin, fibrate or omega-3 fatty acids provides greater opportunity to achieve non-HDL-C and apoB targets, given complementary profiles of lipid-modifying activity and supported by evidence from clinical studies. Improvement in lipid control and reduction in atherogenic risk could be anticipated to translate to benefits in clinical outcomes. PMID:19545870

  13. Abnormally high serum ferritin levels among professional road cyclists

    PubMed Central

    Zotter, H; Robinson, N; Zorzoli, M; Schattenberg, L; Saugy, M; Mangin, P

    2004-01-01

    Background: An international, longitudinal medical follow up examination of male professional road cyclists revealed excessively elevated serum ferritin levels. Objective: To evaluate the importance of elevated ferritin values among professional cyclists, their relationship with age and nationality, and their evolution over 3 years. Methods: Over 1000 serum ferritin values were collected. Other parameters were included in order to exclude conditions which might have increased ferritin levels without changing body iron stores. Results: In 1999, over 45% of riders displayed ferritin values above 300 ng/ml and one fourth levels over 500 ng/ml. These percentages had decreased to 27% and 9%, respectively, 3 years later, while the overall average, which was above the normal limits in 1999, had decreased by 33% in 3 years. Older cyclists had higher ferritin values than younger cyclists. There was also a relationship between ferritin levels and the nationality of the cyclists. Analysis of 714 riders in 2000 and 2002 showed only a slight and insignificant decrease in the mean ferritin value although those with initially elevated iron stores had a much greater decrease. Conclusion: Professional road cyclists used excessive iron supplementation leading to high serum ferritin levels correlating with increased body iron stores. Although the situation progressively improved over 3 years, it remains worrying as increased body iron stores are related to health complications. Therefore, prevention in addition to the fight against doping should be a main goal of the UCI. Aggressive therapy for athletes with excessive ferritin values should be carried out at or before the end of their careers. PMID:15562163

  14. Abnormal Pap Smear and Diagnosis of High-Grade Vaginal Intraepithelial Neoplasia

    PubMed Central

    Sopracordevole, Francesco; Mancioli, Francesca; Clemente, Nicolò; De Piero, Giovanni; Buttignol, Monica; Giorda, Giorgio; Ciavattini, Andrea

    2015-01-01

    Abstract The aim of this study was to analyze the correlation between the first diagnosis of high-grade Vaginal Intraepithelial Neoplasia (HG-VaIN: VaIN 2–VaIN 3) and the cytological abnormalities on the referral pap smear. All the women with histological diagnosis of HG-VaIN consecutively referred to the Gynecological Oncology Unit of the Aviano National Cancer Institute (Aviano, Italy) from January 1991 to April 2014 and with a pap smear performed in the 3 months before the diagnosis were considered, and an observational cohort study was performed. A total of 87 women with diagnosis of HG-VaIN were identified. Major cytological abnormalities (HSIL and ASC-H) on the referral pap smear were significantly more frequent than lesser abnormalities (ASC-US and LSIL) in postmenopausal women (64.9% vs 36.7%, P = 0.02) and in women with a previous diagnosis of HPV-related cervical preinvasive or invasive lesions (70.5% vs 39.5%, P = 0.01). Diagnosis of VaIN 3 was preceded by major cytological abnormalities in most of the cases (72.7% vs 27.3%, P < 0.001). The diagnosis of HG-VaIN can be preceded by different abnormalities on referral pap smear. Major abnormalities are usually reported in postmenopausal women and in women with previous cervical HPV-related disease. However, ASC-US or LSIL do not exclude HG-VaIN, especially VaIN2. An accurate examination of the whole vaginal walls (or vaginal vault) must be performed in all the women who underwent colposcopy for an abnormal pap smear, and a biopsy of all suspicious areas is mandatory. PMID:26496321

  15. Abnormal Pap Smear and Diagnosis of High-Grade Vaginal Intraepithelial Neoplasia: A Retrospective Cohort Study.

    PubMed

    Sopracordevole, Francesco; Mancioli, Francesca; Clemente, Nicolò; De Piero, Giovanni; Buttignol, Monica; Giorda, Giorgio; Ciavattini, Andrea

    2015-10-01

    The aim of this study was to analyze the correlation between the first diagnosis of high-grade Vaginal Intraepithelial Neoplasia (HG-VaIN: VaIN 2-VaIN 3) and the cytological abnormalities on the referral pap smear.All the women with histological diagnosis of HG-VaIN consecutively referred to the Gynecological Oncology Unit of the Aviano National Cancer Institute (Aviano, Italy) from January 1991 to April 2014 and with a pap smear performed in the 3 months before the diagnosis were considered, and an observational cohort study was performed.A total of 87 women with diagnosis of HG-VaIN were identified. Major cytological abnormalities (HSIL and ASC-H) on the referral pap smear were significantly more frequent than lesser abnormalities (ASC-US and LSIL) in postmenopausal women (64.9% vs 36.7%, P = 0.02) and in women with a previous diagnosis of HPV-related cervical preinvasive or invasive lesions (70.5% vs 39.5%, P = 0.01). Diagnosis of VaIN 3 was preceded by major cytological abnormalities in most of the cases (72.7% vs 27.3%, P < 0.001).The diagnosis of HG-VaIN can be preceded by different abnormalities on referral pap smear. Major abnormalities are usually reported in postmenopausal women and in women with previous cervical HPV-related disease. However, ASC-US or LSIL do not exclude HG-VaIN, especially VaIN2. An accurate examination of the whole vaginal walls (or vaginal vault) must be performed in all the women who underwent colposcopy for an abnormal pap smear, and a biopsy of all suspicious areas is mandatory. PMID:26496321

  16. A simulation of three-dimensional systolic flow dynamics in a spherical ventricle: effects of abnormal wall motion.

    PubMed

    Gonzalez, E; Schoephoerster, R T

    1996-01-01

    Alterations in left ventricle (LV) wall motion induced by ischemia will affect flow dynamics, and these altered flow fields can be used to evaluate LV pumping efficiency. LV chamber flow fields were obtained in this study by solving the discretized three-dimensional Navier-Stokes equations for viscous, incompressible unsteady flow by using the finite analytic method. Several cases of abnormal wall motion (AWM) were simulated by a manipulation of the boundary conditions to produce regions of hypokinesis, akinesis, and dyskinesis. These solutions were used to determine the central ejection region (CER), defined as the region of flow domain in which the obtained velocity field vectors are aligned +/- 3 degrees from the LV long axis. A CER coefficient was computed from information on the location and orientation of the CER within the LV cavity. Contraction of the spherical ventricle produced a vector field that was symmetric with respect to the long axis. For the simulations of AWM, an asymmetrical flow pattern developed, became more pronounced with increasing severity of AWM, and resulted in a shorter CER that shifted toward the ischemic region. The CER coefficients decreased monotonically with increased severity in AWM from 0.948 in the normal case to a low of 0.164 for the most severe case of AWM. The CER coefficient quantitatively displayed the sensitivity of the flow patterns to even moderate degrees of hypokinesis. In addition, visualization of the three-dimensional flow field reinforced the necessity of three-dimensional simulations to capture aspects of the flow that existing methods of two-dimensional flow imaging that use ultrasound may miss. PMID:8669717

  17. On a problem of abnormal high local tsunami run-up

    NASA Astrophysics Data System (ADS)

    Kaystrenko, Victor

    2010-05-01

    Analysis of tsunami height distributions along the coast shows that far tsunami sources give a rather homogeneous and smoothed distributions. On the contrary, we have many examples of abnormal high tsunami run-ups produced by the source near the coast. There are Urup tsunami at 20 October 1963, Nihonkai-Chubu tsunami 26 May 1983, Okushiri tsunami 12 July 1993, Indonesia tsunami 26 December 2004 and others. Investigation of Go (1993) showed that mechanism of its forming looks random. The term 'abnormal high' means abnormal high local tsunami run-up comparatively to the one on the nearest part of coast. There are several possible mechanisms of forming of abnormal tsunami height. It can be done by focusing bottom topography or non-linear interaction and other. All of these mechanisms are not investigated to the end. Additionally to it there is one smoothing mechanism which makes tsunami height distributions more homogeneous. We can show that homogeneous shelf is working as smoothing mechanism fir wave field. Tsunami propagation in the shelf zone except area near the coast can be described by linear wave equation ν tt=div(gh grad ν) where ν describes the disturbance of the sea level, g is the gravity acceleration and h is the sea depth.. Investigations of the amplitude-frequency characteristic of the shelf can give a result: there are no abnormal high local tsunami run-ups if tsunami source is locating out of homogeneous shelf zone. The work was supported by Russian foundation for basic research, grant 08-05-01096. REFERENCES Ch.N.Go. The limitation of tsunami wave height. TSUNAMI'93. Proceedings of the International Tsunami Symposium. Wakayama, Japan, August 23-27, 1993, pp. 87-93.

  18. Embolization Treatment of High-Flow Priapism.

    PubMed

    Kim, Kyung Rae

    2016-09-01

    Priapism is prolonged erection that persists beyond or is unrelated to sexual stimulation. There are two main types of priapism: high flow and low flow. The treatment of priapism will differ depending on the diagnosis of these two different types. In particular, interventional radiology plays a key role in treating patients with high-flow priapism. This article will review the diagnosis and treatment of the high-flow priapism. PMID:27582604

  19. Cerebral blood flow is an earlier indicator of perfusion abnormalities than cerebral blood volume in Alzheimer's disease.

    PubMed

    Lacalle-Aurioles, María; Mateos-Pérez, José M; Guzmán-De-Villoria, Juan A; Olazarán, Javier; Cruz-Orduña, Isabel; Alemán-Gómez, Yasser; Martino, María-Elena; Desco, Manuel

    2014-04-01

    The purpose of this study was to elucidate whether cerebral blood flow (CBF) can better characterize perfusion abnormalities in predementia stages of Alzheimer's disease (AD) than cerebral blood volume (CBV) and whether cortical atrophy is more associated with decreased CBV or with decreased CBF. We compared measurements of CBV, CBF, and mean cortical thickness obtained from magnetic resonance images in a group of healthy controls, patients with mild cognitive impairment (MCI) who converted to AD after 2 years of clinical follow-up (MCI-c), and patients with mild AD. A significant decrease in perfusion was detected in the parietal lobes of the MCI-c patients with CBF parametric maps but not with CBV maps. In the MCI-c group, a negative correlation between CBF values and cortical thickness in the right parahippocampal gyrus suggests an increase in CBF that depends on cortical atrophy in predementia stages of AD. Our study also suggests that CBF deficits appear before CBV deficits in the progression of AD, as CBV abnormalities were only detected at the AD stage, whereas CBF changes were already detected in the MCI stage. These results confirm the hypothesis that CBF is a more sensitive parameter than CBV for perfusion abnormalities in MCI-c patients.

  20. Cerebral blood flow is an earlier indicator of perfusion abnormalities than cerebral blood volume in Alzheimer's disease

    PubMed Central

    Lacalle-Aurioles, María; Mateos-Pérez, José M; Guzmán-De-Villoria, Juan A; Olazarán, Javier; Cruz-Orduña, Isabel; Alemán-Gómez, Yasser; Martino, María-Elena; Desco, Manuel

    2014-01-01

    The purpose of this study was to elucidate whether cerebral blood flow (CBF) can better characterize perfusion abnormalities in predementia stages of Alzheimer's disease (AD) than cerebral blood volume (CBV) and whether cortical atrophy is more associated with decreased CBV or with decreased CBF. We compared measurements of CBV, CBF, and mean cortical thickness obtained from magnetic resonance images in a group of healthy controls, patients with mild cognitive impairment (MCI) who converted to AD after 2 years of clinical follow-up (MCI-c), and patients with mild AD. A significant decrease in perfusion was detected in the parietal lobes of the MCI-c patients with CBF parametric maps but not with CBV maps. In the MCI-c group, a negative correlation between CBF values and cortical thickness in the right parahippocampal gyrus suggests an increase in CBF that depends on cortical atrophy in predementia stages of AD. Our study also suggests that CBF deficits appear before CBV deficits in the progression of AD, as CBV abnormalities were only detected at the AD stage, whereas CBF changes were already detected in the MCI stage. These results confirm the hypothesis that CBF is a more sensitive parameter than CBV for perfusion abnormalities in MCI-c patients. PMID:24424381

  1. Abnormal resting regional cerebral blood flow patterns and their correlates in schizophrenia

    SciTech Connect

    Mathew, R.J.; Wilson, W.H.; Tant, S.R.; Robinson, L.; Prakash, R.

    1988-06-01

    Regional cerebral blood flow (CBF) was measured under resting conditions in 108 right-handed schizophrenic inpatients and a matched group of normal controls with the xenon 133 inhalation technique. Forty-six patients were free of all medication for two weeks. There were no significant differences in CBF to the two hemispheres. The patients showed a comparatively reduced anteroposterior (AP) gradient for CBF. Though there were no differences in frontal flow, the patients had higher flow to several postcentral brain regions, bilaterally. Cerebral blood flow in the patients correlated inversely with age and positively with carbon dioxide level. Women had higher flow than men. Duration of the illness was the only significant predictor of the reduced AP gradient in patients. Higher left temporal and right parietal flow were found to be the best discriminators between patients and controls. Mean hemispheric flow to both hemispheres and several brain regions correlated with the total score and the item, unusual thought content, of the Brief Psychiatric Rating Scale. There were no differences in regional CBF between medicated and unmedicated patients.

  2. Chromothripsis Is a Recurrent Genomic Abnormality in High-Risk Myelodysplastic Syndromes

    PubMed Central

    Abáigar, María; Robledo, Cristina; Benito, Rocío; Ramos, Fernando; Díez-Campelo, María; Hermosín, Lourdes; Sánchez-del-Real, Javier; Alonso, Jose M.; Cuello, Rebeca; Megido, Marta; Rodríguez, Juan N.; Martín-Núñez, Guillermo; Aguilar, Carlos; Vargas, Manuel; Martín, Ana A.; García, Juan L.; Kohlmann, Alexander; del Cañizo, M. Consuelo; Hernández-Rivas, Jesús M.

    2016-01-01

    To explore novel genetic abnormalities occurring in myelodysplastic syndromes (MDS) through an integrative study combining array-based comparative genomic hybridization (aCGH) and next-generation sequencing (NGS) in a series of MDS and MDS/myeloproliferative neoplasms (MPN) patients. 301 patients diagnosed with MDS (n = 240) or MDS/MPN (n = 61) were studied at the time of diagnosis. A genome-wide analysis of DNA copy number abnormalities was performed. In addition, a mutational analysis of DNMT3A, TET2, RUNX1, TP53 and BCOR genes was performed by NGS in selected cases. 285 abnormalities were identified in 71 patients (23.6%). Three high-risk MDS cases (1.2%) displayed chromothripsis involving exclusively chromosome 13 and affecting some cancer genes: FLT3, BRCA2 and RB1. All three cases carried TP53 mutations as revealed by NGS. Moreover, in the whole series, the integrative analysis of aCGH and NGS enabled the identification of cryptic recurrent deletions in 2p23.3 (DNMT3A; n = 2.8%), 4q24 (TET2; n = 10%) 17p13 (TP53; n = 8.5%), 21q22 (RUNX1; n = 7%), and Xp11.4 (BCOR; n = 2.8%), while mutations in the non-deleted allele where found only in DNMT3A (n = 1), TET2 (n = 3), and TP53 (n = 4). These cryptic abnormalities were detected mainly in patients with normal (45%) or non-informative (15%) karyotype by conventional cytogenetics, except for those with TP53 deletion and mutation (15%), which had a complex karyotype. In addition to well-known copy number defects, the presence of chromothripsis involving chromosome 13 was a novel recurrent change in high-risk MDS patients. Array CGH analysis revealed the presence of cryptic abnormalities in genomic regions where MDS-related genes, such as TET2, DNMT3A, RUNX1 and BCOR, are located. PMID:27741277

  3. Positive reinforcement training moderates only high levels of abnormal behavior in singly housed rhesus macaques.

    PubMed

    Baker, Kate C; Bloomsmith, Mollie; Neu, Kimberly; Griffis, Caroline; Maloney, Margaret; Oettinger, Brooke; Schoof, Valerie A M; Martinez, Marni

    2009-01-01

    This study evaluated the application of positive reinforcement training (PRT) as an intervention for abnormal behaviors in singly housed laboratory rhesus macaques at 2 large primate facilities. Training involved basic control behaviors and body-part presentation. The study compared baseline behavioral data on 30 adult males and 33 adult females compared with 3 treatment phases presented in counterbalanced order: 6 min per week of PRT, 20 or 40 min per week of PRT, and 6 min per week of unstructured human interaction (HI). Within-subject parametric tests detected no main or interaction effects involving experimental phase. However, among a subset of subjects with levels of abnormal in the top quartile of the range (n = 15), abnormal behavior was reduced from 35% to 25% of samples with PRT but not with HI. These results suggest that short durations of PRT applied as enrichment for this species and in this context may not in itself be sufficient intervention for abnormal behavior because levels remained high. However, it may be appropriate as an adjunct to other interventions and may be best targeted to the most severely affected individuals.

  4. Positive Reinforcement Training Moderates Only High Levels of Abnormal Behavior in Singly Housed Rhesus Macaques

    PubMed Central

    Baker, Kate C.; Bloomsmith, Mollie; Neu, Kimberly; Griffis, Caroline; Maloney, Margaret; Oettinger, Brooke; Schoof, Valérie A. M.; Martinez, Marni

    2010-01-01

    This study evaluated the application of positive reinforcement training (PRT) as an intervention for abnormal behaviors in singly housed laboratory rhesus macaques at 2 large primate facilities. Training involved basic control behaviors and body-part presentation. The study compared baseline behavioral data on 30 adult males and 33 adult females compared with 3 treatment phases presented in counterbalanced order: 6 min per week of PRT, 20 or 40 min per week of PRT, and 6 min per week of unstructured human interaction (HI). Within-subject parametric tests detected no main or interaction effects involving experimental phase. However, among a subset of subjects with levels of abnormal in the top quartile of the range (n = 15), abnormal behavior was reduced from 35% to 25% of samples with PRT but not with HI. These results suggest that short durations of PRT applied as enrichment for this species and in this context may not in itself be sufficient intervention for abnormal behavior because levels remained high. However, it may be appropriate as an adjunct to other interventions and may be best targeted to the most severely affected individuals. PMID:20183477

  5. Studying ventricular abnormalities in mild cognitive impairment with hyperbolic Ricci flow and tensor-based morphometry.

    PubMed

    Shi, Jie; Stonnington, Cynthia M; Thompson, Paul M; Chen, Kewei; Gutman, Boris; Reschke, Cole; Baxter, Leslie C; Reiman, Eric M; Caselli, Richard J; Wang, Yalin

    2015-01-01

    Mild Cognitive Impairment (MCI) is a transitional stage between normal aging and dementia and people with MCI are at high risk of progression to dementia. MCI is attracting increasing attention, as it offers an opportunity to target the disease process during an early symptomatic stage. Structural magnetic resonance imaging (MRI) measures have been the mainstay of Alzheimer's disease (AD) imaging research, however, ventricular morphometry analysis remains challenging because of its complicated topological structure. Here we describe a novel ventricular morphometry system based on the hyperbolic Ricci flow method and tensor-based morphometry (TBM) statistics. Unlike prior ventricular surface parameterization methods, hyperbolic conformal parameterization is angle-preserving and does not have any singularities. Our system generates a one-to-one diffeomorphic mapping between ventricular surfaces with consistent boundary matching conditions. The TBM statistics encode a great deal of surface deformation information that could be inaccessible or overlooked by other methods. We applied our system to the baseline MRI scans of a set of MCI subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI: 71 MCI converters vs. 62 MCI stable). Although the combined ventricular area and volume features did not differ between the two groups, our fine-grained surface analysis revealed significant differences in the ventricular regions close to the temporal lobe and posterior cingulate, structures that are affected early in AD. Significant correlations were also detected between ventricular morphometry, neuropsychological measures, and a previously described imaging index based on fluorodeoxyglucose positron emission tomography (FDG-PET) scans. This novel ventricular morphometry method may offer a new and more sensitive approach to study preclinical and early symptomatic stage AD.

  6. STUDYING VENTRICULAR ABNORMALITIES IN MILD COGNITIVE IMPAIRMENT WITH HYPERBOLIC RICCI FLOW AND TENSOR-BASED MORPHOMETRY

    PubMed Central

    Shi, Jie; Stonnington, Cynthia M.; Thompson, Paul M.; Chen, Kewei; Gutman, Boris; Reschke, Cole; Baxter, Leslie C.; Reiman, Eric M.; Caselli, Richard J.; Wang, Yalin

    2014-01-01

    Mild Cognitive Impairment (MCI) is a transitional stage between normal aging and dementia and people with MCI are at high risk of progression to dementia. MCI is attracting increasing attention, as it offers an opportunity to target the disease process during an early symptomatic stage. Structural magnetic resonance imaging (MRI) measures have been the mainstay of Alzheimer’s disease (AD) imaging research, however, ventricular morphometry analysis remains challenging because of its complicated topological structure. Here we describe a novel ventricular morphometry system based on the hyperbolic Ricci flow method and tensor-based morphometry (TBM) statistics. Unlike prior ventricular surface parameterization methods, hyperbolic conformal parameterization is angle-preserving and does not have any singularities. Our system generates a one-to-one diffeomorphic mapping between ventricular surfaces with consistent boundary matching conditions. The TBM statistics encode a great deal of surface deformation information that could be inaccessible or overlooked by other methods. We applied our system to the baseline MRI scans of a set of MCI subjects from the Alzheimer’s Disease Neuroimaging Initiative (ADNI: 71 MCI converters vs. 62 MCI stable). Although the combined ventricular area and volume features did not differ between the two groups, our fine-grained surface analysis revealed significant differences in the ventricular regions close to the temporal lobe and posterior cingulate, structures that are affected early in AD. Significant correlations were also detected between ventricular morphometry, neuropsychological measures, and a previously described imaging index based on fluorodeoxyglucose positron emission tomography (FDG-PET) scans. This novel ventricular morphometry method may offer a new and more sensitive approach to study preclinical and early symptomatic stage AD. PMID:25285374

  7. High speed flow past wings

    NASA Technical Reports Server (NTRS)

    Norstrud, H.

    1973-01-01

    The analytical solution to the transonic small perturbation equation which describes steady compressible flow past finite wings at subsonic speeds can be expressed as a nonlinear integral equation with the perturbation velocity potential as the unknown function. This known formulation is substituted by a system of nonlinear algebraic equations to which various methods are applicable for its solution. Due to the presence of mathematical discontinuities in the flow solutions, however, a main computational difficulty was to ensure uniqueness of the solutions when local velocities on the wing exceeded the speed of sound. For continuous solutions this was achieved by embedding the algebraic system in an one-parameter operator homotopy in order to apply the method of parametric differentiation. The solution to the initial system of equations appears then as a solution to a Cauchy problem where the initial condition is related to the accompanying incompressible flow solution. In using this technique, however, a continuous dependence of the solution development on the initial data is lost when the solution reaches the minimum bifurcation point. A steepest descent iteration technique was therefore, added to the computational scheme for the calculation of discontinuous flow solutions. Results for purely subsonic flows and supersonic flows with and without compression shocks are given and compared with other available theoretical solutions.

  8. Phenotyping structural abnormalities in mouse embryos using high-resolution episcopic microscopy

    PubMed Central

    Weninger, Wolfgang J.; Geyer, Stefan H.; Martineau, Alexandrine; Galli, Antonella; Adams, David J.; Wilson, Robert; Mohun, Timothy J.

    2014-01-01

    The arrival of simple and reliable methods for 3D imaging of mouse embryos has opened the possibility of analysing normal and abnormal development in a far more systematic and comprehensive manner than has hitherto been possible. This will not only help to extend our understanding of normal tissue and organ development but, by applying the same approach to embryos from genetically modified mouse lines, such imaging studies could also transform our knowledge of gene function in embryogenesis and the aetiology of developmental disorders. The International Mouse Phenotyping Consortium is coordinating efforts to phenotype single gene knockouts covering the entire mouse genome, including characterising developmental defects for those knockout lines that prove to be embryonic lethal. Here, we present a pilot study of 34 such lines, utilising high-resolution episcopic microscopy (HREM) for comprehensive 2D and 3D imaging of homozygous null embryos and their wild-type littermates. We present a simple phenotyping protocol that has been developed to take advantage of the high-resolution images obtained by HREM and that can be used to score tissue and organ abnormalities in a reliable manner. Using this approach with embryos at embryonic day 14.5, we show the wide range of structural abnormalities that are likely to be detected in such studies and the variability in phenotypes between sibling homozygous null embryos. PMID:25256713

  9. High precision high flow range control valve

    DOEpatents

    McCray, John A.

    1999-01-01

    A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90.degree. turn. In the preferred embodiment only one of the two fluid passageways contains a 90.degree. turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings.

  10. High precision high flow range control valve

    DOEpatents

    McCray, J.A.

    1999-07-13

    A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90 [degree] turn. In the preferred embodiment only one of the two fluid passageways contains a 90[degree] turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings. 12 figs.

  11. Flow simulation and analysis of high-power flow batteries

    NASA Astrophysics Data System (ADS)

    Knudsen, E.; Albertus, P.; Cho, K. T.; Weber, A. Z.; Kojic, A.

    2015-12-01

    The cost of a flow battery system can be reduced by increasing its power density and thereby reducing its stack area. If per-pass utilizations are held constant, higher battery power densities can only be achieved using higher flow rates. Here, a 3D computational fluid dynamics model of a flow battery flow field and electrode is used to analyze the implications of increasing flow rates to high power density operating conditions. Interdigitated and serpentine designs, and cell sizes ranging from 10 cm2 to 400 cm2, are simulated. The results quantify the dependence of pressure loss on cell size and design, demonstrating that the details of the passages that distribute flow between individual channels and the inlet and outlet have a major impact on pressure losses in larger cells. Additionally, in-cell flow behavior is analyzed as a function of cell size and design. Flow structures are interrogated to show how and where electrode parameters influence pressure drops, and how regions where transport is slow are correlated with the presence of experimentally observed cell degradation.

  12. Abnormal fluid pressures at ODP Site 1251: Implications for fluid flow and hydrate concentration

    NASA Astrophysics Data System (ADS)

    Weinberger, J. L.; Brown, K. M.

    2005-12-01

    Consolidation test results from whole round samples collected at Ocean Drilling Program (ODP) Site 1251 were combined with geophysical logging-while-drilling (LWD) data to create a continuous down-hole record of fluid pressure in the slope basin to the east of Hydrate Ridge, OR. Underconsolidation of the sediment is documented in the void ratio vs. effective stress relationships from the consolidation studies in the upper 140 mbsf of the section. This interval corresponds with a zone of consistently elevated fluid pressure that reaches ~90% of the lithostatic overburden stress. Models of one dimensional sedimentation and consolidation show that the observed degree of overpressuring can be accounted for by the combined effect of rapid sedimentation (60 to 160 cm/k.y.) and low permeability (1x10-16 to 1x10-17 m2). Between 140 and 300 mbsf the fluid pressure varies from 90% of lithostatic to sub-hydrostatic in 5 distinct horizons. This variation may be linked to mechanical consolidation of the sediment related to pore fluid drainage along more permeable horizons, or changes in sedimentation rate related to either glacial/ interglacial cycles or the uplift history of the ridge. The derived pressure gradient and permeability measurements predict Darcy flow rates on the order of 1 mm/yr at this site, but a lack of laterally continuous permeable conduits likely prevents the flow generated by basin overpressures in the interval from 0 to 140 mbsf from contributing to flow at the crest of the ridge. Using an average methane concentration of 100 mM and the determined flow rate, the methane flux through the system is calculated to be ~5 x 10-11 kg s-1 m-2. These data can be used to examine the maximum theoretical percentage of the pore space that can be filled with hydrate given the time of deposition in the basin. At a depth of 50 mbsf, we find that the maximum concentration of hydrate in the pore space is expected to be 0.1 to 0.3%, agreeing with the lack of concentrated

  13. Abnormally high level of CA-19-9 in a benign ovarian cyst

    PubMed Central

    Pyeon, Seung-Yeon; Park, Ji Young; Lee, Jong-Min

    2015-01-01

    CA-19-9 antigen is mainly elevated in cases of gastrointestinal tract malignancy, including of the pancreas, colorectum, and biliary tract. CA 19-9 antigen can also be elevated in ovarian mucinous neoplasms, however, as well as in many benign conditions. Markedly raised levels of more than 10,000 U/mL were almost observed in advanced stage of malignancy. We report herein the case of a 37-year-old woman who presented with an abnormally high level of CA 19-9 antigen associated with benign mucinous cystadenoma. PMID:26623421

  14. Abnormally high level of CA-19-9 in a benign ovarian cyst.

    PubMed

    Pyeon, Seung-Yeon; Park, Ji Young; Ki, Kyung-Do; Lee, Jong-Min

    2015-11-01

    CA-19-9 antigen is mainly elevated in cases of gastrointestinal tract malignancy, including of the pancreas, colorectum, and biliary tract. CA 19-9 antigen can also be elevated in ovarian mucinous neoplasms, however, as well as in many benign conditions. Markedly raised levels of more than 10,000 U/mL were almost observed in advanced stage of malignancy. We report herein the case of a 37-year-old woman who presented with an abnormally high level of CA 19-9 antigen associated with benign mucinous cystadenoma.

  15. ACE Reduces Metabolic Abnormalities in a High-Fat Diet Mouse Model

    PubMed Central

    Lee, Seong-Jong; Han, Jong-Min; Lee, Jin-Seok; Son, Chang-Gue; Im, Hwi-Jin; Jo, Hyun-Kyung; Yoo, Ho-Ryong; Kim, Yoon-Sik; Seol, In-Chan

    2015-01-01

    The medicinal plants Artemisia iwayomogi (A. iwayomogi) and Curcuma longa (C. longa) radix have been used to treat metabolic abnormalities in traditional Korean medicine and traditional Chinese medicine (TKM and TCM). In this study we evaluated the effect of the water extract of a mixture of A. iwayomogi and C. longa (ACE) on high-fat diet-induced metabolic syndrome in a mouse model. Four groups of C57BL/6N male mice (except for the naive group) were fed a high-fat diet freely for 10 weeks. Among these, three groups (except the control group) were administered a high-fat diet supplemented with ACE (100 or 200 mg/kg) or curcumin (50 mg/kg). Body weight, accumulation of adipose tissues in abdomen and size of adipocytes, serum lipid profiles, hepatic steatosis, and oxidative stress markers were analyzed. ACE significantly reduced the body and peritoneal adipose tissue weights, serum lipid profiles (total cholesterol and triglycerides), glucose levels, hepatic lipid accumulation, and oxidative stress markers. ACE normalized lipid synthesis-associated gene expressions (peroxisome proliferator-activated receptor gamma, PPARγ; fatty acid synthase, FAS; sterol regulatory element-binding transcription factor-1c, SREBP-1c; and peroxisome proliferator-activated receptor alpha, PPARα). The results from this study suggest that ACE has the pharmaceutical potential reducing the metabolic abnormalities in an animal model. PMID:26508977

  16. Abnormal High-Frequency Burst Firing of Cerebellar Neurons in Rapid-Onset Dystonia-Parkinsonism

    PubMed Central

    Fremont, Rachel; Calderon, D. Paola; Maleki, Sara

    2014-01-01

    Loss-of-function mutations in the α3 isoform of the Na+/K+ ATPase (sodium pump) are responsible for rapid-onset dystonia parkinsonism (DYT12). Recently, a pharmacological model of DYT12 was generated implicating both the cerebellum and basal ganglia in the disorder. Notably, partially blocking sodium pumps in the cerebellum was necessary and sufficient for induction of dystonia. Thus, a key question that remains is how partially blocking sodium pumps in the cerebellum induces dystonia. In vivo recordings from dystonic mice revealed abnormal high-frequency bursting activity in neurons of the deep cerebellar nuclei (DCN), which comprise the bulk of cerebellar output. In the same mice, Purkinje cells, which provide strong inhibitory drive to DCN cells, also fired in a similarly erratic manner. In vitro studies demonstrated that Purkinje cells are highly sensitive to sodium pump dysfunction that alters the intrinsic pacemaking of these neurons, resulting in erratic burst firing similar to that identified in vivo. This abnormal firing abates when sodium pump function is restored and dystonia caused by partial block of sodium pumps can be similarly alleviated. These findings suggest that persistent high-frequency burst firing of cerebellar neurons caused by sodium pump dysfunction underlies dystonia in this model of DYT12. PMID:25164667

  17. High-Speed Granular Chute Flows

    NASA Astrophysics Data System (ADS)

    McElwaine, J.

    2014-12-01

    Accurate models for high speed granular flows are critical for understanding long runout landslides and rockfalls. However reproducible experimental data is extremely limited and is mostly only available for steady state flows on moderate inclinations. We report on experiments over a much greater range of slope angles 30-50 degrees and flow depths 4-130 particle diameters with upto 20kg/s of sand flowing steadily. The data suggests that friction can be much larger than the μ(I)mu(I) rheology or kinetic theories predict and suggest and that there may be constant velocity states above the angle of vanishing hstop. We show similar high speed steady flows at angles up to 50 degress in Discrete Element Simuations and discuss how these can be understood theoretically.

  18. Normal and abnormal evolution of argon metastable density in high-density plasmas

    SciTech Connect

    Seo, B. H.; Kim, J. H.; You, S. J.

    2015-05-15

    A controversial problem on the evolution of Ar metastable density as a function of electron density (increasing trend versus decreasing trend) was resolved by discovering the anomalous evolution of the argon metastable density with increasing electron density (discharge power), including both trends of the metastable density [Daltrini et al., Appl. Phys. Lett. 92, 061504 (2008)]. Later, by virtue of an adequate physical explanation based on a simple global model, both evolutions of the metastable density were comprehensively understood as part of the abnormal evolution occurring at low- and high-density regimes, respectively, and thus the physics behind the metastable evolution has seemed to be clearly disclosed. In this study, however, a remarkable result for the metastable density behavior with increasing electron density was observed: even in the same electron density regime, there are both normal and abnormal evolutions of metastable-state density with electron density depending on the measurement position: The metastable density increases with increasing electron density at a position far from the inductively coupled plasma antenna but decreases at a position close to the antenna. The effect of electron temperature, which is spatially nonuniform in the plasma, on the electron population and depopulation processes of Argon metastable atoms with increasing electron density is a clue to understanding the results. The calculated results of the global model, including multistep ionization for the argon metastable state and measured electron temperature, are in a good agreement with the experimental results.

  19. High quality topic extraction from business news explains abnormal financial market volatility.

    PubMed

    Hisano, Ryohei; Sornette, Didier; Mizuno, Takayuki; Ohnishi, Takaaki; Watanabe, Tsutomu

    2013-01-01

    Understanding the mutual relationships between information flows and social activity in society today is one of the cornerstones of the social sciences. In financial economics, the key issue in this regard is understanding and quantifying how news of all possible types (geopolitical, environmental, social, financial, economic, etc.) affects trading and the pricing of firms in organized stock markets. In this article, we seek to address this issue by performing an analysis of more than 24 million news records provided by Thompson Reuters and of their relationship with trading activity for 206 major stocks in the S&P US stock index. We show that the whole landscape of news that affects stock price movements can be automatically summarized via simple regularized regressions between trading activity and news information pieces decomposed, with the help of simple topic modeling techniques, into their "thematic" features. Using these methods, we are able to estimate and quantify the impacts of news on trading. We introduce network-based visualization techniques to represent the whole landscape of news information associated with a basket of stocks. The examination of the words that are representative of the topic distributions confirms that our method is able to extract the significant pieces of information influencing the stock market. Our results show that one of the most puzzling stylized facts in financial economies, namely that at certain times trading volumes appear to be "abnormally large," can be partially explained by the flow of news. In this sense, our results prove that there is no "excess trading," when restricting to times when news is genuinely novel and provides relevant financial information.

  20. High Quality Topic Extraction from Business News Explains Abnormal Financial Market Volatility

    PubMed Central

    Hisano, Ryohei; Sornette, Didier; Mizuno, Takayuki; Ohnishi, Takaaki; Watanabe, Tsutomu

    2013-01-01

    Understanding the mutual relationships between information flows and social activity in society today is one of the cornerstones of the social sciences. In financial economics, the key issue in this regard is understanding and quantifying how news of all possible types (geopolitical, environmental, social, financial, economic, etc.) affects trading and the pricing of firms in organized stock markets. In this article, we seek to address this issue by performing an analysis of more than 24 million news records provided by Thompson Reuters and of their relationship with trading activity for 206 major stocks in the S&P US stock index. We show that the whole landscape of news that affects stock price movements can be automatically summarized via simple regularized regressions between trading activity and news information pieces decomposed, with the help of simple topic modeling techniques, into their “thematic” features. Using these methods, we are able to estimate and quantify the impacts of news on trading. We introduce network-based visualization techniques to represent the whole landscape of news information associated with a basket of stocks. The examination of the words that are representative of the topic distributions confirms that our method is able to extract the significant pieces of information influencing the stock market. Our results show that one of the most puzzling stylized facts in financial economies, namely that at certain times trading volumes appear to be “abnormally large,” can be partially explained by the flow of news. In this sense, our results prove that there is no “excess trading,” when restricting to times when news is genuinely novel and provides relevant financial information. PMID:23762258

  1. Pipe flow of highly concentrated sludge.

    PubMed

    Slatter, Paul

    2008-11-01

    Industries that pump sludges experience pressure to operate at higher concentrations with sludges that have high mechanical strength properties. The viscous character of the sludge becomes increasingly non-Newtonian and yield stress in nature. The two principal problems are regime determination and laminar flow settling, which ultimately results in pipe blockage. In facing the diversities that sludge management currently presents, it is important to resolve these issues and develop solutions for engineering practice. The approaches developed at the Flow Process Research Centre to deal with these problems are introduced. The objectives of this paper are to introduce experimental data of the phenomena associated with the pipe flow of highly concentrated sludge, and use these to develop and evaluate predictive modeling approaches suitable for engineering design purposes. For the prediction of transitional flow, a new general approach for visco-plastic fluids in industrially relevant pipe sizes is presented, based on dimensional analysis of the flow problem. Settled bed behavior is modeled using an adapted two-layer model approach, in all flow regimes. The modeling approaches are evaluated using the experimental results obtained. The analysis shows that the present work provides a workable solution for the prediction of the pipe flow of highly concentrated sludges, for engineering design purposes.

  2. High energy density redox flow device

    SciTech Connect

    Chiang, Yet-Ming; Carter, W. Craig; Ho, Bryan Y; Duduta, Mihai; Limthongkul, Pimpa

    2014-05-13

    Redox flow devices are described in which at least one of the positive electrode or negative electrode-active materials is a semi-solid or is a condensed ion-storing electroactive material, and in which at least one of the electrode-active materials is transported to and from an assembly at which the electrochemical reaction occurs, producing electrical energy. The electronic conductivity of the semi-solid is increased by the addition of conductive particles to suspensions and/or via the surface modification of the solid in semi-solids (e.g., by coating the solid with a more electron conductive coating material to increase the power of the device). High energy density and high power redox flow devices are disclosed. The redox flow devices described herein can also include one or more inventive design features. In addition, inventive chemistries for use in redox flow devices are also described.

  3. A high flow turbine CPAP system.

    PubMed

    Moran, J L; Jackson, M P; Cameron, D M; Peisach, A R; Cunningham, D N; O'Fathartaigh, M S

    1988-01-01

    A continuous high flow CPAP system incorporating a turbine blower is described. The system achieves inspiratory flow rates of 150 l/min or more by means of reticulated gas flow and inspired oxygen fractions of 0.21-0.95. Positive airway pressure is provided by weighted disc valves and a modified aviation-type CPAP face mask provides electronic communication with the patient. The mobility of the system also enables its use as an intermittent physiotherapy aid. Work of breathing of the system, as assessed by total pressure fluctuations is at a minimum.

  4. Abnormalities of CSF flow patterns in the cerebral aqueduct in treatment-resistant late-life depression: a potential biomarker of microvascular angiopathy.

    PubMed

    Naish, Josephine H; Baldwin, Robert C; Patankar, Tufail; Jeffries, Suzanne; Burns, Alistair S; Taylor, Christopher J; Waterton, John C; Jackson, Alan

    2006-09-01

    There is growing evidence that microvascular angiopathy (MVA) plays an important role in the development of dementia and affective disorders in older people. At currently available image resolutions it is not possible to image directly the vascular changes associated with MVA, but the effects on blood and cerebrospinal fluid (CSF) flow may be detectable. The aim of this study was to investigate a potential biomarker for MVA based on MRI of abnormalities in CSF flow. Since there is considerable indirect evidence that treatment resistance in late-onset depressive disorder is related to MVA, we assessed the method in a group of 22 normal volunteers and 29 patients with responsive (N=21) or treatment-resistant (N=8) late-onset depressive disorder. Single-slice quantified phase-contrast (PC) images of cerebral blood and CSF flow were collected at 15 points over a cardiac cycle, and the resulting flow curves were parameterized. Significant differences in the CSF flow (width of systolic flow peak and diastolic flow volume, both P<0.01) through the cerebral aqueduct were observed for the group of treatment-resistant patients when compared to age matched controls. No significant difference was observed for a group of 21 patients with treatment-responsive depression. The findings support the hypothesis that MR measurement of CSF flow abnormalities provides a biomarker of MVA, and thus could have application in a wide range of age-related diseases.

  5. Digital valve for high pressure high flow applications

    NASA Astrophysics Data System (ADS)

    Badescu, Mircea; Sherrit, Stewart; Lewis, Derek; Bao, Xiaoqi; Bar-Cohen, Yoseph; Hall, Jeffery L.

    2016-04-01

    To address the challenges, which are involved with the development of flow control valves that can meet high demand requirements such as high pressure, high flow rate, limited power and limited space, the authors have conceived a novel design configuration. This design consists of a digitalized flow control valve with multipath and multistage pressure reduction structures. Specifically, the valve is configured as a set of parallel flow paths from the inlet to the outlet. A choke valve controls the total flow rate by digitally opening different paths or different combination of the paths. Each path is controlled by a poppet cap valve basically operated in on-off states. The number of flow states is 2N where N is the number of flow paths. To avoid erosion from sand in the fluid and high speed flow, the seal area of the poppet cap valve is located at a distance from the flow inlet away from the high speed flow and the speed is controlled to stay below a predefined erosion safe limit. The path is a multistage structure composed of a set of serial nozzles-expansion chambers that equally distribute the total pressure drop to each stage. The pressure drop of each stage and, therefore, the flow speed at the nozzles and expansion chambers is controlled by the number of stages. The paths have relatively small cross section and could be relatively long for large number of stages and still fit in a strict annular space limit. The paper will present the design configuration, analysis and preliminary test results.

  6. High frequency of p53/MDM2/p14ARF pathway abnormalities in relapsed neuroblastoma

    PubMed Central

    Carr-Wilkinson, Jane; O' Toole, Kieran; Wood, Katrina M.; Challen, Christine C.; Baker, Angela G.; Board, Julian R.; Evans, Laura; Cole, Michael; Cheung, Nai-Kong V.; Boos, Joachim; Köhler, Gabriele; Leuschner, Ivo; Pearson, Andrew D.J.; Lunec, John; Tweddle, Deborah A.

    2010-01-01

    Purpose: Most neuroblastomas initially respond to therapy but many relapse with chemoresistant disease. p53 mutations are rare in diagnostic neuroblastomas, but we have previously reported inactivation of the p53/MDM2/p14ARF pathway in 9/17 (53%) neuroblastoma cell lines established at relapse. Hypothesis: Inactivation of the p53/MDM2/p14ARF pathway develops during treatment and contributes to neuroblastoma relapse. Methods: Eighty-four neuroblastomas were studied from 41 patients with relapsed neuroblastoma including 38 paired neuroblastomas at different stages of therapy. p53 mutations were detected by automated sequencing, p14ARF methylation and deletion by methylation-specific PCR and duplex PCR respectively, and MDM2 amplification by fluorescent in-situ hybridisation. Results: Abnormalities in the p53 pathway were identified in 20/41(49%) cases. Downstream defects due to inactivating missense p53 mutations were identified in 6/41 (15%) cases, 5 following chemotherapy and/or at relapse and 1 at diagnosis, post chemotherapy and relapse. The presence of a p53 mutation was independently prognostic for overall survival (hazard ratio 3.4, 95% confidence interval 1.2, 9.9; p = 0.02). Upstream defects were present in 35% cases: MDM2 amplification in 3 cases, all at diagnosis & relapse and p14ARF inactivation in 12/41 (29%) cases: 3 had p14ARF methylation, 2 after chemotherapy, and 9 had homozygous deletions, 8 at diagnosis and relapse. Conclusions: These results show that a high proportion of neuroblastomas which relapse have an abnormality in the p53 pathway. The majority have upstream defects suggesting that agents which reactivate wild-type p53 would be beneficial, in contrast to those with downstream defects where p53 independent therapies are indicated. PMID:20145180

  7. Chaotic behaviour of high Mach number flows

    NASA Technical Reports Server (NTRS)

    Varvoglis, H.; Ghosh, S.

    1985-01-01

    The stability of the super-Alfvenic flow of a two-fluid plasma model with respect to the Mach number and the angle between the flow direction and the magnetic field is investigated. It is found that, in general, a large scale chaotic region develops around the initial equilibrium of the laminar flow when the Mach number exceeds a certain threshold value. After reaching a maximum the size of this region begins shrinking and goes to zero as the Mach number tends to infinity. As a result high Mach number flows in time independent astrophysical plasmas may lead to the formation of 'quasi-shocks' in the presence of little or no dissipation.

  8. High prevalence of hypertriglyceridaemia and apolipoprotein abnormalities in coronary artery disease.

    PubMed Central

    Barbir, M; Wile, D; Trayner, I; Aber, V R; Thompson, G R

    1988-01-01

    Serum lipids and apolipoproteins A-I and B were measured in 174 men aged less than 60 with angiographically confirmed coronary artery disease and in 572 healthy control men. Two thirds of the patients had raised age-corrected values of fasting serum cholesterol and/or triglyceride and/or a low high density lipoprotein (HDL) cholesterol compared with the controls. Eighteen (30%) of the 61 normolipidaemic patients had a concentration of serum apolipoprotein A-I below the 5th percentile of 233 controls. In normolipidaemic patients on beta blockers the relative prevalence of serum low density lipoprotein (LDL)-apolipoprotein B values above the 95th percentile of 339 controls was significantly increased. Discriminant function analysis showed that a raised concentration of serum triglyceride was the best discriminant between patients and controls, with raised LDL-apolipoprotein B and reduced apolipoprotein A-I coming second only to triglyceride in analyses where each was separately compared with all the lipid variables. These associations were highly significant and were independent of other influences, including beta blockade. These findings re-emphasise the importance of hypertriglyceridaemia as a risk factor and confirm that apolipoprotein abnormalities occur frequently in coronary disease, even in normolipidaemic patients. PMID:3203033

  9. Abnormalities of Neuronal Oscillations and Temporal Integration to Low and High Frequency Auditory Stimulation in Schizophrenia

    PubMed Central

    Hamm, Jordan P.; Gilmore, Casey S.; Picchetti, Natalie A.M.; Sponheim, Scott R.; Clementz, Brett A.

    2011-01-01

    Background Electro- and magneto-encephalography (E/MEG) studies indicate among schizophrenia patients (SZ) abnormal, often reduced, entrained (steady-state; aSSR) and transient (N100/M100) neural responses to auditory stimuli. We complement this literature by focusing analyses on auditory cortices, assessing a wide range of stimulation frequencies with long driving periods, and evaluating relationships between aSSR and M100 reductions in SZ. Method Seventeen SZ and 17 healthy subjects (H) participated. Stimuli were 1500ms binaural broadband noise sequences modulated at 5, 20, 40, 80 or 160-Hz. MEG data were collected and co-registered with structural magnetic resonance images. aSSRs and M100s projected into brain space were analyzed as a function of hemisphere, stimulus density, and time. Results aSSR: At low (5-Hz) and high (80-Hz) modulation frequencies, SZ displayed weaker entrainment bilaterally. To 40-Hz stimuli, SZ showed weaker entrainment only in right auditory cortex. M100: While responses for H increased linearly with stimulus density, this effect was weaker or absent in SZ. Relationship: A principal components analysis of SZ deficits identified low (5-Hz entrainment and M100) and high (40–80-Hz entrainment) frequency components. Discriminant analysis indicated that the low frequency component uniquely differentiated SZ from H. The high frequency component correlated with negative symptoms among SZ. Conclusions SZ auditory cortices were unable to (i) generate healthy levels of theta- and high gamma-band (80Hz) entrainment (aSSR) and (ii) augment transient responses (M100s) to rapidly presented auditory information (an index of temporal integration). Only the latter was most apparent in left hemisphere, and may reflect a prominent neurophysiological deficit in schizophrenia. PMID:21216392

  10. Early-stage visual processing abnormalities in high-functioning autism spectrum disorder (ASD).

    PubMed

    Baruth, Joshua M; Casanova, Manuel F; Sears, Lonnie; Sokhadze, Estate

    2010-06-01

    It has been reported that individuals with autism spectrum disorder (ASD) have abnormal responses to the sensory environment. For these individuals sensory overload can impair functioning, raise physiological stress, and adversely affect social interaction. Early-stage (i.e. within 200ms of stimulus onset) auditory processing abnormalities have been widely examined in ASD using event-related potentials (ERP), while ERP studies investigating early-stage visual processing in ASD are less frequent. We wanted to test the hypothesis of early-stage visual processing abnormalities in ASD by investigating ERPs elicited in a visual oddball task using illusory figures. Our results indicate that individuals with ASD have abnormally large cortical responses to task irrelevant stimuli over both parieto-occipital and frontal regions-of-interest (ROI) during early stages of visual processing compared to the control group. Furthermore, ASD patients showed signs of an overall disruption in stimulus discrimination, and had a significantly higher rate of motor response errors.

  11. Flow Interaction With Highly Flexible Structures

    NASA Astrophysics Data System (ADS)

    Shoele, Kourosh

    Studying the interaction between fluid and structure is an essential step towards the understanding of many engineering and physical problems, from the flow instability of structures to the biolocomotion of insects, birds and fishes. The simulation of such problems is computationally challenging. This justifies the attempts to develop more sophisticated and more efficient numerical models of fluid-solid interactions. In this dissertation, we proposed numerical models both in potential flow and fully viscous flow for the interaction of immersed structure with a strongly unsteady flow. In particular we have developed efficient approaches to study two groups of problems, the flow interaction with skeleton-reinforced fish fins and flow interaction with highly flexible bluff bodies. Fins of bony fishes are characterized by a skeleton-reinforced membrane structure consisting of a soft collagen membrane strengthened by embedded flexible rays. Morphologically, each ray is connected to a group of muscles so that the fish can control the rotational motion of each ray individually, enabling multi-degree of freedom control over the fin motion and deformation. We have developed fluid-structure interaction models to simulate the kinematics and dynamic performance of a structurally idealized fin. The first method includes a boundary-element model of the fluid motion and a fully-nonlinear Euler-Bernoulli beam model of the embedded rays. In the second method, we use an improved immersed boundary approach. Using these models, we study thrust generation and propulsion efficiency of the fin at different combinations of parameters at both high-Re and intermediate-Re flow. Effects of kinematic as well as structural properties are examined. It has been illustrated that the fish's capacity to control the motion of each individual ray, as well as the anisotropic deformability of the fin determined by distribution of the rays (especially the detailed distribution of ray stiffness), is

  12. Abnormal high-energy phosphate molecule metabolism during regional brain activation in patients with bipolar disorder.

    PubMed

    Yuksel, C; Du, F; Ravichandran, C; Goldbach, J R; Thida, T; Lin, P; Dora, B; Gelda, J; O'Connor, L; Sehovic, S; Gruber, S; Ongur, D; Cohen, B M

    2015-09-01

    Converging evidence suggests bioenergetic abnormalities in bipolar disorder (BD). In the brain, phosphocreatine (PCr) acts a reservoir of high-energy phosphate (HEP) bonds, and creatine kinases (CK) catalyze the transfer of HEP from adenosine triphosphate (ATP) to PCr and from PCr back to ATP, at times of increased need. This study examined the activity of this mechanism in BD by measuring the levels of HEP molecules during a stimulus paradigm that increased local energy demand. Twenty-three patients diagnosed with BD-I and 22 healthy controls (HC) were included. Levels of phosphorus metabolites were measured at baseline and during visual stimulation in the occipital lobe using (31)P magnetic resonance spectroscopy at 4T. Changes in metabolite levels showed different patterns between the groups. During stimulation, HC had significant reductions in PCr but not in ATP, as expected. In contrast, BD patients had significant reductions in ATP but not in PCr. In addition, PCr/ATP ratio was lower at baseline in patients, and there was a higher change in this measure during stimulation. This pattern suggests a disease-related failure to replenish ATP from PCr through CK enzyme catalysis during tissue activation. Further studies measuring the CK flux in BD are required to confirm and extend this finding.

  13. High phosphate feeding promotes mineral and bone abnormalities in mice with chronic kidney disease

    PubMed Central

    Lau, Wei Ling; Linnes, Michael; Chu, Emily Y.; Foster, Brian L.; Bartley, Bryan A.; Somerman, Martha J.; Giachelli, Cecilia M.

    2013-01-01

    Background Chronic kidney disease-mineral bone disorder (CKD-MBD) is a systemic syndrome characterized by imbalances in mineral homeostasis, renal osteodystrophy (ROD) and ectopic calcification. The mechanisms underlying this syndrome in individuals with chronic kidney disease (CKD) are not yet clear. Methods We examined the effect of normal phosphate (NP) or high phosphate (HP) feeding in the setting of CKD on bone pathology, serum biochemistry and vascular calcification in calcification-prone dilute brown non-agouti (DBA/2) mice. Results In both NP and HP-fed CKD mice, elevated serum parathyroid hormone and alkaline phosphatase (ALP) levels were observed, but serum phosphorus levels were equivalent compared with sham controls. CKD mice on NP diet showed trabecular alterations in the long bone consistent with high–turnover ROD, including increased trabecular number with abundant osteoblasts and osteoclasts. Despite trabecular bone and serum biochemical changes, CKD/NP mice did not develop vascular calcification. In contrast, CKD/HP mice developed arterial medial calcification (AMC), more severe trabecular bone alterations and cortical bone abnormalities that included decreased cortical thickness and density, and increased cortical porosity. Cortical bone porosity and trabecular number strongly correlated with the degree of aortic calcification. Conclusions HP feeding was required to induce the full spectrum of CKD-MBD symptoms in CKD mice. PMID:23045434

  14. Reproductive and behavioral abnormalities in tree swallows with high levels of PCB contamination

    SciTech Connect

    McCarty, J. |; Secord, A.; Tillitt, D.

    1995-12-31

    Tree Swallows (Tachycineta bicolor) breeding along the Hudson River forage extensively on PCB contaminated insects that emerge from the river. The authors studied the reproductive ecology and behavior of tree swallows breeding at several sites along the Hudson River. These sites vary in the severity of PCB contamination. PCB levels in both eggs and chicks were found to be among the highest ever reported in this species, with concentrations comparable to those found in aquatic organisms in the Hudson River. In 1994 reproductive success at PCB contaminated sites was significantly impaired, relative to other sites in New York. Reduced reproductive success was largely attributed to high levels of nest abandonment during incubation and reduced hatchability of eggs. Growth and development of nestlings was not significantly impaired. Abnormal nest building behavior was also noted in 1994, and this was studied in detail in 1995. Nests from contaminated areas are significantly smaller than those at a nearby reference site and at other sites in New York. The authors suggest that the reduced reproductive outputs at these sites are, in large part, a result of effects on the behavior of incubating females. The population-level implications of these patterns are unknown.

  15. Numerical models for high beta magnetohydrodynamic flow

    SciTech Connect

    Brackbill, J.U.

    1987-01-01

    The fundamentals of numerical magnetohydrodynamics for highly conducting, high-beta plasmas are outlined. The discussions emphasize the physical properties of the flow, and how elementary concepts in numerical analysis can be applied to the construction of finite difference approximations that capture these features. The linear and nonlinear stability of explicit and implicit differencing in time is examined, the origin and effect of numerical diffusion in the calculation of convective transport is described, and a technique for maintaining solenoidality in the magnetic field is developed. Many of the points are illustrated by numerical examples. The techniques described are applicable to the time-dependent, high-beta flows normally encountered in magnetically confined plasmas, plasma switches, and space and astrophysical plasmas. 40 refs.

  16. Abnormally high thromboxane biosynthesis in homozygous homocystinuria. Evidence for platelet involvement and probucol-sensitive mechanism.

    PubMed Central

    Di Minno, G; Davì, G; Margaglione, M; Cirillo, F; Grandone, E; Ciabattoni, G; Catalano, I; Strisciuglio, P; Andria, G; Patrono, C

    1993-01-01

    Homocystinuria due to homozygous cystathionine beta-synthase deficiency is an inborn error of metabolism characterized by a high incidence of thrombosis and premature atherosclerosis. We evaluated TXA2 biosynthesis in vivo and several in vitro tests of platelet function in 11 homocystinuric patients and 12 healthy controls. In vitro, patients' platelet aggregation was within control values as were TXB2 formation, fibrinogen binding, and ATP secretion in response to thrombin. In contrast, the urinary excretion of 11-dehydro-TXB2, a major enzymatic derivative of TXA2, was > 2 SD of controls in all patients (1,724 +/- 828 pg/mg creatinine, mean +/- SD, in patients vs. 345 +/- 136 in controls, P < 0.001). The administration to four patients of low-dose aspirin (50 mg/d for 1 wk) reduced metabolite excretion by > 80%. The recovery of 11-dehydro-TXB2 excretion over the 10 d that followed aspirin cessation occurred with a pattern consistent with the entry into the circulation of platelets with intact cyclooxygenase activity. Prolonged partial reduction in the abnormally high excretion of both 11-dehydro-TXB2 and 2,3-dinor-TXB2, was also observed in seven patients who ingested 500 mg daily for 3 wk of the antioxidant drug probucol. These results provide evidence for enhanced thromboxane biosynthesis in homocystinuria and for its partial dependence on probucol-sensitive mechanisms. Furthermore, the elevated TXA2 formation in homocystinuria is likely to reflect, at least in part, in vivo platelet activation. PMID:8376592

  17. Abnormal pressures as hydrodynamic phenomena

    USGS Publications Warehouse

    Neuzil, C.E.

    1995-01-01

    So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

  18. Deletion of PTH rescues skeletal abnormalities and high osteopontin levels in Klotho-/- mice.

    PubMed

    Yuan, Quan; Sato, Tadatoshi; Densmore, Michael; Saito, Hiroaki; Schüler, Christiane; Erben, Reinhold G; Lanske, Beate

    2012-01-01

    Maintenance of normal mineral ion homeostasis is crucial for many biological activities, including proper mineralization of the skeleton. Parathyroid hormone (PTH), Klotho, and FGF23 have been shown to act as key regulators of serum calcium and phosphate homeostasis through a complex feedback mechanism. The phenotypes of Fgf23(-/-) and Klotho(-/-) (Kl(-/-)) mice are very similar and include hypercalcemia, hyperphosphatemia, hypervitaminosis D, suppressed PTH levels, and severe osteomalacia/osteoidosis. We recently reported that complete ablation of PTH from Fgf23(-/-) mice ameliorated the phenotype in Fgf23(-/-)/PTH(-/-) mice by suppressing serum vitamin D and calcium levels. The severe osteomalacia in Fgf23(-/-) mice, however, persisted, suggesting that a different mechanism is responsible for this mineralization defect. In the current study, we demonstrate that deletion of PTH from Kl(-/-) (Kl(-/-)/PTH(-/-) or DKO) mice corrects the abnormal skeletal phenotype. Bone turnover markers are restored to wild-type levels; and, more importantly, the skeletal mineralization defect is completely rescued in Kl(-/-)/PTH(-/-) mice. Interestingly, the correction of the osteomalacia is accompanied by a reduction in the high levels of osteopontin (Opn) in bone and serum. Such a reduction in Opn levels could not be observed in Fgf23(-/-)/PTH(-/-) mice, and these mice showed sustained osteomalacia. This significant in vivo finding is corroborated by in vitro studies using calvarial osteoblast cultures that show normalized Opn expression and rescued mineralization in Kl(-/-)/PTH(-/-) mice. Moreover, continuous PTH infusion of Kl(-/-) mice significantly increased Opn levels and osteoid volume, and decreased trabecular bone volume. In summary, our results demonstrate for the first time that PTH directly impacts the mineralization disorders and skeletal deformities of Kl(-/-), but not of Fgf23(-/-) mice, possibly by regulating Opn expression. These are significant new perceptions

  19. Computation of high-speed reacting flows

    NASA Astrophysics Data System (ADS)

    Clutter, James Keith

    A computational study has been conducted for high-speed reacting flows relevant to munition problems, including shock-induced combustion and gun muzzle blast. The theoretical model considers inviscid and viscous flows, multi-species, finite rate chemical reaction schemes, and turbulence. Both the physical and numerical aspects are investigated to determine their impact on simulation accuracy. A range of hydrogen and oxygen reaction mechanisms are evaluated for the shock-induced combustion flow scenario. Characteristics of the mechanisms such as the induction time, heat release rate, and second explosion limit are found to impact the accuracy of the computation. On the numerical side, reaction source term treatments, including logarithmic weighting and scaling modifications, are investigated to determine their effectiveness in addressing numerical errors caused by disparate length scales between chemical reactions and fluid dynamics. It is demonstrated that these techniques can enhance solution accuracy. Computations of shock-induced combustion have also been performed using a κ-ɛ model to account for the turbulent transport of species and heat. An algebraic model of the temperature fluctuations has been used to estimate the impact of the turbulent effect on the chemical reaction source terms. The turbulence effects when represented with the current models are found to be minimal in the shock-induced combustion flow investigated in the present work. For the gun system simulations, computations for both a large caliber howitzer and small caliber firearms are carried out. A reduced kinetic scheme and an algebraic turbulence model are employed. The present approach, which accounts for the chemical reaction aspects of the gun muzzle blast problem, is found to improve the prediction of peak overpressures and can capture the effects produced by small caliber firearm sound suppressors. The present study has established the numerical and physical requirements for

  20. High-End Computing for Incompressible Flows

    NASA Technical Reports Server (NTRS)

    Kwak, Dochan; Kiris, Cetin

    2001-01-01

    The objective of the First MIT Conference on Computational Fluid and Solid Mechanics (June 12-14, 2001) is to bring together industry and academia (and government) to nurture the next generation in computational mechanics. The objective of the current talk, 'High-End Computing for Incompressible Flows', is to discuss some of the current issues in large scale computing for mission-oriented tasks.

  1. Implications of perennial saline springs for abnormally high fluid pressures and active thrusting in western California

    SciTech Connect

    Unruh, J.R.; Davisson, M.L.; Criss, R.E.; Moores, E.M. )

    1992-05-01

    Perennial saline springs in the Rumsey Hills area, southwestern Sacramento Valley, California, locally discharge at high elevations and near ridgetops. The springs are cold, are commonly associated with natural gas seeps, and typically emerge along west-vergent thrust faults. Stable isotope analyses indicate that the spring waters are similar to oil-field formation fluids and they have had a significant residence time in the subsurface at moderate temperatures. The nonmeteoric character of the springs demonstrates that they are not being fed by perched water tables. The authors propose that these subsurface formation waters are being forced to the surface by anomalously high porefluid pressures. The Rumsey Hills area is one of Quaternary uplift, thrusting, and crustal shortening, and prospect wells drilled there have encountered anomalously high fluid pressures at shallow depths. They attribute these high fluid pressures to active tectonic compression and shortening of Cretaceous marine sedimentary rocks. The widespread occurrence of anomalously high pore-fluid pressures and perennial saline springs in the Coast Ranges and western Great Valley suggests that much of western California may be characterized as a seismically active, overpressured thrust belt. The emergence of formation waters along thrust faults further suggests that patterns of subsurface fluid flow in western California may be similar to those in overpressured accretionary prisms, and that excess fluid pressures may also play a role in the distribution of seismicity.

  2. High enthalpy hypersonic boundary layer flow

    NASA Technical Reports Server (NTRS)

    Yanow, G.

    1972-01-01

    A theoretical and experimental study of an ionizing laminar boundary layer formed by a very high enthalpy flow (in excess of 12 eV per atom or 7000 cal/gm) with allowance for the presence of helium driver gas is described. The theoretical investigation has shown that the use of variable transport properties and their respective derivatives is very important in the solution of equilibrium boundary layer equations of high enthalpy flow. The effect of low level helium contamination on the surface heat transfer rate is minimal. The variation of ionization is much smaller in a chemically frozen boundary layer solution than in an equilibrium boundary layer calculation and consequently, the variation of the transport properties in the case of the former was not essential in the integration. The experiments have been conducted in a free piston shock tunnel, and a detailed study of its nozzle operation, including the effects of low levels of helium driver gas contamination has been made. Neither the extreme solutions of an equilibrium nor of a frozen boundary layer will adequately predict surface heat transfer rate in very high enthalpy flows.

  3. The mass mortality of blue mussels (Mytilus spp.) from the Atlantic coast of France is associated with heavy genomic abnormalities as evidenced by flow cytometry.

    PubMed

    Benabdelmouna, Abdellah; Ledu, Christophe

    2016-07-01

    Since 2014, France's blue mussel industry has been facing heavy mortality outbreaks (90-100%) affecting both juveniles and adults. This report presents evidence of heavy genomic abnormalities associated with mortality outbreaks in blue mussels, Mytilus edulis-galloprovincialis, from the Atlantic coast of France. In this study, ploidy characteristics of hemic cells were investigated using Flow CytoMetry (FCM), revealing an unusual, broad continuum of ploidy distribution from hypodiploidy to tetraploidy. FCM was additionally used to evaluate, at individual and populations levels, different thresholds of genomic abnormality (GA%) using the percentage of non-diploid nuclei. Individual mussels were considered to be abnormal when more than 10% of hemocytes in S-G2/M phase were present. At the population level, a threshold of 6% for the mean intensity of the abnormality is proposed, which means in the population, more than 6% of individual mussels have to present with more than 10% of their hemocytes in S-G2/M phase. GA% was found to be significantly predictive of the final mortality. Based on the established thresholds, only two mussel stocks analyzed in this study were considered to have good cytogenetic quality, while all other stocks appeared to be affected. FCM offers a very powerful tool to help manage current blue mussel mortality in France. We also believe that annual and extensive determination of cytogenetic quality of wild and cultivated mussel beds along with exclusive use of FCM-qualified mussel seeds should be a priority. PMID:27264803

  4. Early-stage visual processing abnormalities in high-functioning autism spectrum disorder (ASD)

    PubMed Central

    Baruth, Joshua M.; Casanova, Manuel F.; Sears, Lonnie; Sokhadze, Estate

    2012-01-01

    It has been reported that individuals with autism spectrum disorder (ASD) have abnormal responses to the sensory environment. For these individuals sensory overload can impair functioning, raise physiological stress, and adversely affect social interaction. Early-stage (i.e. within 200ms of stimulus onset) auditory processing abnormalities have been widely examined in ASD using event-related potentials (ERP), while ERP studies investigating early-stage visual processing in ASD are less frequent. We wanted to test the hypothesis of early-stage visual processing abnormalities in ASD by investigating ERPs elicited in a visual oddball task using illusory figures. Our results indicate that individuals with ASD have abnormally large cortical responses to task irrelevant stimuli over both parieto-occipital and frontal regions-of-interest (ROI) during early stages of visual processing compared to the control group. Furthermore, ASD patients showed signs of an overall disruption in stimulus discrimination, and had a significantly higher rate of motor response errors. PMID:22563527

  5. Analytical Investigation of Flow Through High-speed Mixed-flow Turbine

    NASA Technical Reports Server (NTRS)

    Stewart, Warner L

    1951-01-01

    An analysis was made of the flow trough a high-speed mixed-flow turbine based on axially symmetric conditions. The calculated weight flow was lower than that used in the two-dimensional design. The rotor could be redesigned to increase the weight flow and a flow and alleviate undesirable pressure gradients at the expense of increased rotor blade stresses.

  6. Turbulence modeling for high speed compressible flows

    NASA Technical Reports Server (NTRS)

    Chandra, Suresh

    1993-01-01

    The following grant objectives were delineated in the proposal to NASA: to offer course work in computational fluid dynamics (CFD) and related areas to enable mechanical engineering students at North Carolina A&T State University (N.C. A&TSU) to pursue M.S. studies in CFD, and to enable students and faculty to engage in research in high speed compressible flows. Since no CFD-related activity existed at N.C. A&TSU before the start of the NASA grant period, training of students in the CFD area and initiation of research in high speed compressible flows were proposed as the key aspects of the project. To that end, graduate level courses in CFD, boundary layer theory, and fluid dynamics were offered. This effort included initiating a CFD course for graduate students. Also, research work was performed on studying compressibility effects in high speed flows. Specifically, a modified compressible dissipation model, which included a fourth order turbulent Mach number term, was incorporated into the SPARK code and verified for the air-air mixing layer case. The results obtained for this case were compared with a wide variety of experimental data to discern the trends in the mixing layer growth rates with varying convective Mach numbers. Comparison of the predictions of the study with the results of several analytical models was also carried out. The details of the research study are described in the publication entitled 'Compressibility Effects in Modeling Turbulent High Speed Mixing Layers,' which is attached to this report.

  7. Turbulence modeling for high speed compressible flows

    NASA Astrophysics Data System (ADS)

    Chandra, Suresh

    1993-08-01

    The following grant objectives were delineated in the proposal to NASA: to offer course work in computational fluid dynamics (CFD) and related areas to enable mechanical engineering students at North Carolina A&T State University (N.C. A&TSU) to pursue M.S. studies in CFD, and to enable students and faculty to engage in research in high speed compressible flows. Since no CFD-related activity existed at N.C. A&TSU before the start of the NASA grant period, training of students in the CFD area and initiation of research in high speed compressible flows were proposed as the key aspects of the project. To that end, graduate level courses in CFD, boundary layer theory, and fluid dynamics were offered. This effort included initiating a CFD course for graduate students. Also, research work was performed on studying compressibility effects in high speed flows. Specifically, a modified compressible dissipation model, which included a fourth order turbulent Mach number term, was incorporated into the SPARK code and verified for the air-air mixing layer case. The results obtained for this case were compared with a wide variety of experimental data to discern the trends in the mixing layer growth rates with varying convective Mach numbers. Comparison of the predictions of the study with the results of several analytical models was also carried out. The details of the research study are described in the publication entitled 'Compressibility Effects in Modeling Turbulent High Speed Mixing Layers,' which is attached to this report.

  8. Flow cytometric differentiation of abnormal and normal plasma cells in the bone marrow in patients with multiple myeloma and its precursor diseases.

    PubMed

    Tembhare, Prashant R; Yuan, Constance M; Venzon, David; Braylan, Raul; Korde, Neha; Manasanch, Elisabet; Zuchlinsky, Diamond; Calvo, Katherine; Kurlander, Roger; Bhutani, Manisha; Tageja, Nishant; Maric, Irina; Mulquin, Marcia; Roschewski, Mark; Kwok, Mary; Liewehr, David; Landgren, Ola; Stetler-Stevenson, Maryalice

    2014-03-01

    Flow cytometric (FC) enumeration of abnormal plasma cells (APCs) for diagnosis and prognostication of plasma cell dyscrasias (PCD) is challenging. We studied antigen expression in normal plasma cells (NPC) (N = 34) and APC in a series of unselected PCD (N = 59). NPC subpopulations often demonstrated CD19(-), CD20(+), CD45(-) or dim and CD56(+), an immunophenotype observed in PCD. However abnormal CD81 was only observed in APCs (APC detection sensitivity 95%; specificity 100%). We evaluated differences in antigen expression patterns among MGUS (N = 14), SMM (N = 35) and MM (N = 10), finding the combination of CD45 and CD56 helpful in differentiating MGUS from SMM and MM (p = 0.0002). PMID:24462038

  9. Sultan - forced flow, high field test facility

    SciTech Connect

    Horvath, I.; Vecsey, G.; Weymuth, P.; Zellweger, J.

    1981-09-01

    Three European laboratories: CNEN (Frascati, I) ECN (Petten, NL) and SIN (Villigen, CH) decided to coordinate their development efforts and to install a common high field forced flow test facility at Villigen Switzerland. The test facility SULTAN (Supraleiter Testanlage) is presently under construction. As a first step, an 8T/1m bore solenoid with cryogenic periphery will be ready in 1981. The cryogenic system, data acquisition system and power supplies which are contributed by SIN are described. Experimental feasibilities, including cooling, and instrumentation are reviewed. Progress of components and facility construction is described. Planned extension of the background field up to 12T by insert coils is outlined. 5 refs.

  10. Abnormal monsoon years and their control on erosion and sediment flux in the high, arid northwest Himalaya

    NASA Astrophysics Data System (ADS)

    Bookhagen, Bodo; Thiede, Rasmus C.; Strecker, Manfred R.

    2005-02-01

    The interplay between topography and Indian summer monsoon circulation profoundly controls precipitation distribution, sediment transport, and river discharge along the Southern Himalayan Mountain Front (SHF). The Higher Himalayas form a major orographic barrier that separates humid sectors to the south and arid regions to the north. During the Indian summer monsoon, vortices transport moisture from the Bay of Bengal, swirl along the SHF to the northwest, and cause heavy rainfall when colliding with the mountain front. In the eastern and central parts of the Himalaya, precipitation measurements derived from passive microwave analysis (SSM/I) show a strong gradient, with high values at medium elevations and extensive penetration of moisture along major river valleys into the orogen. The end of the monsoonal conveyer belt is near the Sutlej Valley in the NW Himalaya, where precipitation is lower and rainfall maxima move to lower elevations. This region thus comprises a climatic transition zone that is very sensitive to changes in Indian summer monsoon strength. To constrain magnitude, temporal, and spatial distribution of precipitation, we analyzed high-resolution passive microwave data from the last decade and identified an abnormal monsoon year (AMY) in 2002. During the 2002 AMY, violent rainstorms conquered orographic barriers and penetrated far into otherwise arid regions in the northwest Himalaya at elevations in excess of 3 km asl. While precipitation in these regions was significantly increased and triggered extensive erosional processes (i.e., debris flows) on sparsely vegetated, steep hillslopes, mean rainfall along the low to medium elevations was not significantly greater in magnitude. This shift may thus play an important role in the overall sediment flux toward the Himalayan foreland. Using extended precipitation and sediment flux records for the last century, we show that these events have a decadal recurrence interval during the present-day monsoon

  11. Abnormal aortic fatty acid composition and small artery function in offspring of rats fed a high fat diet in pregnancy

    PubMed Central

    Ghosh, P; Bitsanis, D; Ghebremeskel, K; Crawford, M A; Poston, L

    2001-01-01

    Disturbances of the in utero environment are associated with an increased risk of cardiovascular disease in adulthood. In this study we have determined whether abnormal vascular function in the adult offspring of rats fed a high saturated fat diet in pregnancy is associated with altered plasma lipids or vascular fatty acid content. Female Sprague-Dawley rats were fed a breeding diet (4 % fat) or a diet high in saturated fat (20 % fat) for 10 days prior to and throughout pregnancy, and during weaning. Female offspring were then fed a maintenance diet (3 % fat) until 160 days of age. Endothelium-dependent relaxation induced by acetylcholine was blunted in isolated branches of the femoral artery from 160-day-old female offspring of dams fed the saturated fat diet when compared with female offspring of dams fed the breeding diet. These offspring exhibited elevated plasma triglyceride and reduced plasma high density lipoprotein cholesterol concentrations. The fatty acid composition of the aortas was abnormal, with a marked reduction in the content of arachidonic and docosahexaenoic acids. This study demonstrates that a high fat diet in pregnant rats produces abnormal vascular function, plasma lipid disturbances and altered vascular fatty acid content in their female offspring during adulthood. PMID:11410637

  12. Do high blood folate concentrations exacerbate metabolic abnormalities in people with low vitamin B-12 status?123

    PubMed Central

    Mills, James L; Carter, Tonia C; Scott, John M; Troendle, James F; Gibney, Eileen R; Shane, Barry; Kirke, Peadar N; Ueland, Per M; Brody, Lawrence C; Molloy, Anne M

    2011-01-01

    Background: In elderly individuals with low serum vitamin B-12, those who have high serum folate have been reported to have greater abnormalities in the following biomarkers for vitamin B-12 deficiency: low hemoglobin and elevated total homocysteine (tHcy) and methylmalonic acid (MMA). This suggests that folate exacerbates vitamin B-12–related metabolic abnormalities. Objective: We determined whether high serum folate in individuals with low serum vitamin B-12 increases the deleterious effects of low vitamin B-12 on biomarkers of vitamin B-12 cellular function. Design: In this cross-sectional study, 2507 university students provided data on medical history and exposure to folic acid and vitamin B-12 supplements. Blood was collected to measure serum and red blood cell folate (RCF), hemoglobin, plasma tHcy, and MMA, holotranscobalamin, and ferritin in serum. Results: In subjects with low vitamin B-12 concentrations (<148 pmol/L), those who had high folate concentrations (>30 nmol/L; group 1) did not show greater abnormalities in vitamin B-12 cellular function in any area than did those with lower folate concentrations (≤30 nmol/L; group 2). Group 1 had significantly higher holotranscobalamin and RCF, significantly lower tHcy, and nonsignificantly lower (P = 0.057) MMA concentrations than did group 2. The groups did not differ significantly in hemoglobin or ferritin. Compared with group 2, group 1 had significantly higher mean intakes of folic acid and vitamin B-12 from supplements and fortified food. Conclusions: In this young adult population, high folate concentrations did not exacerbate the biochemical abnormalities related to vitamin B-12 deficiency. These results provide reassurance that folic acid in fortified foods and supplements does not interfere with vitamin B-12 metabolism at the cellular level in a healthy population. PMID:21653798

  13. Relationships (II) of International Classification of High-resolution Computed Tomography for Occupational and Environmental Respiratory Diseases with ventilatory functions indices for parenchymal abnormalities

    PubMed Central

    TAMURA, Taro; SUGANUMA, Narufumi; HERING, Kurt G.; VEHMAS, Tapio; ITOH, Harumi; AKIRA, Masanori; TAKASHIMA, Yoshihiro; HIRANO, Harukazu; KUSAKA, Yukinori

    2015-01-01

    The International Classification of High-Resolution Computed Tomography (HRCT) for Occupational and Environmental Respiratory Diseases (ICOERD) is used to screen and diagnose respiratory illnesses. Using univariate and multivariate analysis, we investigated the relationship between subject characteristics and parenchymal abnormalities according to ICOERD, and the results of ventilatory function tests (VFT). Thirty-five patients with and 27 controls without mineral-dust exposure underwent VFT and HRCT. We recorded all subjects’ occupational history for mineral dust exposure and smoking history. Experts independently assessed HRCT using the ICOERD parenchymal abnormalities (Items) grades for well-defined rounded opacities (RO), linear and/or irregular opacities (IR), and emphysema (EM). High-resolution computed tomography showed that 11 patients had RO; 15 patients, IR; and 19 patients, EM. According to the multiple regression model, age and height had significant associations with many indices ventilatory functions such as vital capacity, forced vital capacity, and forced expiratory volume in 1 s (FEV1). The EM summed grades on the upper, middle, and lower zones of the right and left lungs also had significant associations with FEV1 and the maximum mid-expiratory flow rate. The results suggest the ICOERD notation is adequate based on the good and significant multiple regression modeling of ventilatory function with the EM summed grades. PMID:25810443

  14. High prevalence of abnormal adrenal response in girls with central precocious puberty at early pubertal stages.

    PubMed

    Lazar, L; Kauli, R; Bruchis, C; Nordenberg, J; Galatzer, A; Pertzelan, A

    1995-10-01

    Abnormal adrenal response is often observed in girls with precocious adrenarche (1). We studied the adrenal response in 112 girls with idiopathic true central precocious puberty (CPP) at early stages of puberty compared to that in 21 girls with normal puberty (controls). The aims of this study were to determine the prevalence of abnormal adrenal response at early stages of puberty, the possible correlation of abnormal adrenal response with pubertal signs at onset of puberty and with plasma androgen levels, and a possible association with the activity of the hypothalamic-pituitary-gonadal (HPG) axis. All participants underwent a combined i.v. adrenocorticotropic hormone (ACTH)-gonadotropin-releasing hormone (GnRH) test at Tanner stage 2-3: 62 of the CPP girls before and 50 during treatment with GnRH analog. The stimulated levels of 17-hydroxypregnenolone (17OHPreg) and the stimulated 17OHPreg/17-hydroxyprogesterone ratio were analyzed and compared to previously reported norms. The result revealed three patterns of adrenal response: normal (17OHPreg < or = 24 nmol/l and 17OHPreg/17OHP ratio < or = 7) in 50/112 (44.6%) CPP patients and 17/21 (80.9%) controls; exaggerated (17OHPreg > 24 nmol/l, 17OHPreg/17OHP ratio < or = 7) in 50/112 (44.6%) CPP patients and 3/21 (14.3%) controls; and non-classical 3 beta-hydroxysteroid dehydrogenase deficiency (17OHPreg > 24 nmol/l and 17OHPreg/17OHP ratio > 7) in 12/112 (10.8%) CPP patients and 1/21 (4.8%) controls. The clinical features at onset of puberty were comparable in all girls with the CPP in spite of the different adrenal response patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. A functional Magnetic Resonance Imaging study of neurohemodynamic abnormalities during emotion processing in subjects at high risk for schizophrenia

    PubMed Central

    Venkatasubramanian, Ganesan; Puthumana, Dawn Thomas K.; Jayakumar, Peruvumba N.; Gangadhar, B. N.

    2010-01-01

    Background: Emotion processing abnormalities are considered among the core deficits in schizophrenia. Subjects at high risk (HR) for schizophrenia also show these deficits. Structural neuroimaging studies examining unaffected relatives at high risk for schizophrenia have demonstrated neuroanatomical abnormalities involving neo-cortical and sub-cortical brain regions related to emotion processing. The brain functional correlates of emotion processing in these HR subjects in the context of ecologically valid, real-life dynamic images using functional Magnetic Resonance Imaging (fMRI) has not been examined previously. Aim: To examine the neurohemodynamic abnormalities during emotion processing in unaffected subjects at high risk for schizophrenia in comparison with age-, sex-, handedness- and education-matched healthy controls, using fMRI. Materials and Methods: HR subjects for schizophrenia (n=17) and matched healthy controls (n=16) were examined. The emotion processing of fearful facial expression was examined using a culturally appropriate and valid tool for Indian subjects. The fMRI was performed in a 1.5-T scanner during an implicit emotion processing paradigm. The fMRI analyses were performed using the Statistical Parametric Mapping 2 (SPM2) software. Results: HR subjects had significantly reduced brain activations in left insula, left medial frontal gyrus, left inferior frontal gyrus, right cingulate gyrus, right precentral gyrus and right inferior parietal lobule. Hypothesis-driven region-of-interest analysis revealed hypoactivation of right amygdala in HR subjects. Conclusions: Study findings suggest that neurohemodynamic abnormalities involving limbic and frontal cortices could be potential indicators for increased vulnerability toward schizophrenia. The clinical utility of these novel findings in predicting the development of psychosis needs to be evaluated. PMID:21267363

  16. Meiotic abnormalities

    SciTech Connect

    1993-12-31

    Chapter 19, describes meiotic abnormalities. These include nondisjunction of autosomes and sex chromosomes, genetic and environmental causes of nondisjunction, misdivision of the centromere, chromosomally abnormal human sperm, male infertility, parental age, and origin of diploid gametes. 57 refs., 2 figs., 1 tab.

  17. Respiratory symptoms in rheumatoid arthritis: relation to pulmonary abnormalities detected by high-resolution CT and pulmonary functional testing.

    PubMed

    Youssef, Amir A; Machaly, Shereen A; El-Dosoky, Mohammed E; El-Maghraby, Nermeen M

    2012-07-01

    Pulmonary disease is the most frequent and among the most severe extra-articular manifestation of rheumatoid arthritis (RA). However, this issue has not been sufficiently studied in Egyptian patients. The objectives of the present study are to investigate the prevalence and types of pulmonary involvement using high-resolution computed tomography scan (HRCT) and pulmonary function tests (PFT) and evaluate the association between respiratory symptoms and RA-lung disease in a group of Egyptian RA patients. Thirty-six RA patients were recruited; 34 females (94.4%) and 2 males (5.6%) with median age of 48.5 years, and none of them was smoker. Detailed medical and drug histories were obtained. PFT, plain X-ray of the chest, and HRCT were performed to all subjects involved. Nearly 64% of RA patients demonstrated abnormalities in PFT and 47% in HRCT. Mixed restrictive and obstructive pattern was the commonest. Nearly two-thirds of our patients reported one or more pulmonary symptom whether dyspnea, cough, wheezing, or phlegm. Dyspnea was the most frequent symptom. Respiratory symptoms were statistically more common in patients with lung disease. The advanced age, high radiological score, and severity of rheumatoid disease were found to be predictive of lung involvement. Among respiratory symptoms, dyspnea and cough were associated with any pulmonary abnormalities. When specific pulmonary abnormalities were considered, only dyspnea was identified as predictor for restriction. For obstructive abnormality, both cough and wheezing provided valid prediction. We conclude that pulmonary involvement is a common manifestation in Egyptian RA patients, and the pattern of involvement is generally consistent with other studies that were performed worldwide. Specific respiratory symptoms could be used as practical, easy, and cost-effective method, especially in older and with more severe RA patients, to discriminate patients in need of subsequent PFT and HRCT imaging.

  18. Ethylene Trace-gas Techniques for High-speed Flows

    NASA Technical Reports Server (NTRS)

    Davis, David O.; Reichert, Bruce A.

    1994-01-01

    Three applications of the ethylene trace-gas technique to high-speed flows are described: flow-field tracking, air-to-air mixing, and bleed mass-flow measurement. The technique involves injecting a non-reacting gas (ethylene) into the flow field and measuring the concentration distribution in a downstream plane. From the distributions, information about flow development, mixing, and mass-flow rates can be dtermined. The trace-gas apparatus and special considerations for use in high-speed flow are discussed. A description of each application, including uncertainty estimates is followed by a demonstrative example.

  19. Abnormally Low or High Ankle-Brachial Index Is Associated with Proliferative Diabetic Retinopathy in Type 2 Diabetic Mellitus Patients

    PubMed Central

    Chen, Szu-Chia; Hsiao, Pi-Jung; Huang, Jiun-Chi; Lin, Kun-Der; Hsu, Wei-Hao; Lee, Yu-Li; Lee, Mei-Yueh; Chang, Jer-Ming; Shin, Shyi–Jang

    2015-01-01

    Although some studies have reported that low ankle-brachial index (ABI) is associated with diabetic retinopathy (DR) in diabetic patients, it remains controversial as to which stage of DR. The aim of this study is to assess whether peripheral artery disease (PAD), indicated by abnormally low or high ABI, is associated with different stages of DR in patients with type 2 diabetes mellitus (DM), and further evaluate the risk factors. A total of 2001 (858 men and 1143 women) patients with type 2 DM who underwent ABI measurement in an outpatient clinic were enrolled. PAD was defined as ABI < 0.9 or ≧ 1.3 in either leg. DR was classified as non-DR, nonproliferative DR and proliferative DR stages. The clinical data were analyzed and the risk factors for abnormal ABI were determined by multivariate logistic regression analysis. The prevalence of ABI < 0.9 or ≧ 1.3 was 3.0%. Multivariate forward logistic regression analysis identified proliferative DR (vs. non-DR) was associated with abnormal ABI (odds ratio, 1.718; 95% confidence interval, 1.152 to 2.562; p = 0.008), but nonproliferative DR was not. Furthermore, the presence of coronary artery disease, cerebrovascular disease, declining renal function and patients without diuretics use were associated with abnormal ABI in patients with proliferative DR. Our study in patients of type 2 DM demonstrated that PAD was associated with proliferative DR. We emphasize the recommendation of performing the ABI test in this population at risk. PMID:26230390

  20. Highly Inclined Jets in Cross Flow

    NASA Technical Reports Server (NTRS)

    Milanovic, I. M.; Zaman, K. B. M. Q.

    2003-01-01

    Results from an experimental investigation of flow field generated by pitched and yawed jets discharging from a flat plate into a cross-flow are presented. The circular jet was pitched at alpha = 20deg and 45deg and yawed between Beta = 0deg and 90deg in increments of 15deg. The measurements were performed with two ×-wires providing all three components of velocity and turbulent stresses. These data were obtained at downstream locations of x = 3, 5, 10 and 20, where the distance x, normalized by the jet diameter, is measured from the center of the orifice. Data for all configurations were acquired at a momentum-flux ratio J = 8. Additionally, for selected angles and locations, surveys were conducted for J = 1.5, 4, and 20. As expected, the jet penetration is found to be higher at larger alpha. With increasing beta the jet spreads more. The rate of reduction of peak streamwise vorticity, ? max, with the downstream distance is significantly less at higher Beta but is found to be practically independent of alpha. Thus, at the farthest measurement station x = 20, ?xmax is about five times larger for Beta = 75deg compared to the levels at Beta = 0deg. Streamwise velocity within the jet-vortex structure is found to depend on the parameter J. At J = 1.5 and 4, 'wake-like' velocity profiles are observed. In comparison, a 'jet-like' overshoot is present at higher J. Distributions of turbulent stresses for various cases are documented. Peak normal stresses are found to occur within the core of the streamwise vortices. With yaw, at lower values of J, high turbulence is also observed in the boundary layer underneath the jet-vortex structure

  1. High-Speed Granular Chute Flows

    NASA Astrophysics Data System (ADS)

    McElwaine, Jim

    2014-05-01

    Nearly all granular flow models have a maximum value for the friction and therefore predict that flows on steep slopes will accelerate at a constant rate until the interaction with the ambient fluid becomes important. This prediction has not been tested by previous work, which has focused on relatively low slope angles where steady, fully developed flows occur after short distances. We report on experiments where we investigating flows over a much greater range of slope angles 30-50 degrees and flow depths 4-130 particle diameters with up to 20kg/s of sand flowing steadily. The data suggests that friction can be much larger than the mu(I) rheology or kinetic theories predict and suggest and that there may be constant velocity states above the angle of vanishing hstop.

  2. Simulating Pressure Effects of High-Flow Volumes

    NASA Technical Reports Server (NTRS)

    Kaufman, M.

    1985-01-01

    Dynamic test stresses realized without high-volume pumps. Assembled in Sections in gas-flow passage, contoured mandrel restricts flow rate to valve convenient for testing and spatially varies pressure on passage walls to simulate operating-pressure profile. Realistic test pressures thereby achieved without extremely high flow volumes.

  3. Assessment of abnormal blood flow and efficacy of treatment in patients with systemic sclerosis using a newly developed microwireless laser Doppler flowmeter and arm-raising test.

    PubMed

    Kido, M; Takeuchi, S; Hayashida, S; Urabe, K; Sawada, R; Furue, M

    2007-10-01

    Background Patients with systemic sclerosis (SSc) frequently suffer from recalcitrant digital ulceration because of impaired cutaneous blood flow (CBF). A simple and accurate CBF measurement would be helpful to evaluate the disease status and efficacy of treatment in such patients. Objectives To examine the feasibility of a newly developed, micromachined integrated laser blood flowmeter (MILBF) for evaluation of abnormal CBF responses in patients with SSc. Methods CBF of finger pulp was measured in eight patients with SSc and in six healthy controls using MILBF. CBF in the steady state and the responses to the arm-raising test and cold provocation were assessed. The therapeutic efficacy of a single and an intensive prostaglandin E(1) (PGE(1)) infusion treatment was also evaluated in some of the SSc patients. Results The patients with SSc showed significantly lower steady-state CBF than controls. The rate of blood flow with cold provocation and the velocity of blood flow recovery after cold provocation (VR-CP) tended to be lower in patients with SSc. Augmentation of amplitude of the digital pulse wave by arm raising (AA-AR) was observed in controls, but not in patients with SSc. We also found that VR-CP and AA-AR may be good markers for evaluating the efficacy of vasodilatory treatment. It should be noted that the examined patients did not complain of any pain and/or distress during the arm-raising test, as opposed to during cold provocation. Conclusions CBF assessment using MILBF and an arm-raising test is accurate, noninvasive and well tolerated and thus the combination may be a better alternative method to evaluate abnormal CBF and efficacy of treatment in patients with SSc.

  4. Craniofacial Abnormalities

    MedlinePlus

    ... of the skull and face. Craniofacial abnormalities are birth defects of the face or head. Some, like cleft ... palate, are among the most common of all birth defects. Others are very rare. Most of them affect ...

  5. Chromosome Abnormalities

    MedlinePlus

    ... decade, newer techniques have been developed that allow scientists and doctors to screen for chromosomal abnormalities without using a microscope. These newer methods compare the patient's DNA to a normal DNA ...

  6. Walking abnormalities

    MedlinePlus

    ... include: Arthritis of the leg or foot joints Conversion disorder (a psychological disorder) Foot problems (such as a ... injuries. For an abnormal gait that occurs with conversion disorder, counseling and support from family members are strongly ...

  7. Nail abnormalities

    MedlinePlus

    Beau's lines; Fingernail abnormalities; Spoon nails; Onycholysis; Leukonychia; Koilonychia; Brittle nails ... Just like the skin, the fingernails tell a lot about your health: ... the fingernail. These lines can occur after illness, injury to ...

  8. The “Little AVM”: A New Entity in High-flow versus Low-flow Vascular Malformations

    PubMed Central

    Stein, Michael; Guilfoyle, Regan; Courtemanche, Douglas J.; Moss, Wendy; Bucevska, Marija

    2014-01-01

    Background: Arteriovenous malformations (AVMs) are high-flow lesions with abnormal connections between arteries and veins without an intervening capillary bed. Infrequently, the radiographic diagnosis of a vascular lesion will not support the clinical diagnosis of an AVM. These “discrepant” lesions are not adequately captured within the current classification system and represent a treatment dilemma. The purpose of this study is to review our center’s experience with vascular malformations where incongruity in a patient’s clinical and radiographic presentation produces a diagnostic and therapeutic challenge. Methods: A retrospective chart review of patients with atypical AVM pre sen ta tions was performed. Parameters reviewed included patient history and demogra phics, clinical presentation, radiological imaging, and treatment modalities. Results: Over a 15-year period, we identified 7 cases of vascular malformations with discrepant clinical and radiological findings concerning flow characteristics. All patients were treated based on their radiological diagnosis and most were managed with sclerotherapy. No lesions evolved into a high-flow process, and there was no recurrence at a minimum of 24 months of follow-up. Conclusions: We have identified and described a unique subcategory of vascular malformations that have clinical features of high-flow malformations but radiological features of low-flow malformations. These lesions behave like low-flow malformations and should be treated as such. We propose that complex vascular malformations are best evaluated by both clinical and specialized diagnostic radiological means; the radiologic diagnoses should supplant what is found clinically, and ultimately treatment should be preferentially based on a radiological diagnosis. PMID:25426370

  9. High frequency stimulation of the STN restored the abnormal high-voltage spindles in the cortex and the globus pallidus of 6-OHDA lesioned rats.

    PubMed

    Yang, Chen; Zhang, Jia-Rui; Chen, Lei; Ge, Shun-Nan; Wang, Jue-Lei; Yan, Zhi-Qiang; Jia, Dong; Zhu, Jun-Ling; Gao, Guo-Dong

    2015-05-19

    Many studies showed that abnormal oscillations in the cortical-basal ganglia loop is involved in the pathophysiology of Parkinson's disease (PD). In contrast to the well-studied beta synchronization, high-voltage spindles (HVSs), another type of abnormal oscillation observed in PD, are neglected. To explore the role of subthalamic nucleus-deep brain stimulation (STN-DBS) in HVSs regulation, we simultaneously recorded the local field potential (LFP) in the globus pallidus (GP) and electrocorticogram (ECoG) in the primary motor cortex(M1) in freely moving 6-hydroxydopamine (6-OHDA) lesioned or control rats before, during, and after STN-DBS. Consistent with our previous study, HVSs occurrence, duration, and relative power and coherence between the M1 cortex and GP increased in 6-OHDA lesioned rats. We found that high but not low frequency stimulation restored the abnormal HVSs activity and motor deficit. These results suggest that the STN is involved in the abnormal oscillation between the M1 cortex and GP.

  10. High speed flow cytometric separation of viable cells

    DOEpatents

    Sasaki, D.T.; Van den Engh, G.J.; Buckie, A.M.

    1995-11-14

    Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

  11. High speed flow cytometric separation of viable cells

    DOEpatents

    Sasaki, Dennis T.; Van den Engh, Gerrit J.; Buckie, Anne-Marie

    1995-01-01

    Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

  12. Flow “Fine” Synthesis: High Yielding and Selective Organic Synthesis by Flow Methods

    PubMed Central

    2015-01-01

    Abstract The concept of flow “fine” synthesis, that is, high yielding and selective organic synthesis by flow methods, is described. Some examples of flow “fine” synthesis of natural products and APIs are discussed. Flow methods have several advantages over batch methods in terms of environmental compatibility, efficiency, and safety. However, synthesis by flow methods is more difficult than synthesis by batch methods. Indeed, it has been considered that synthesis by flow methods can be applicable for the production of simple gasses but that it is difficult to apply to the synthesis of complex molecules such as natural products and APIs. Therefore, organic synthesis of such complex molecules has been conducted by batch methods. On the other hand, syntheses and reactions that attain high yields and high selectivities by flow methods are increasingly reported. Flow methods are leading candidates for the next generation of manufacturing methods that can mitigate environmental concerns toward sustainable society. PMID:26337828

  13. Flow "Fine" Synthesis: High Yielding and Selective Organic Synthesis by Flow Methods.

    PubMed

    Kobayashi, Shū

    2016-02-18

    The concept of flow "fine" synthesis, that is, high yielding and selective organic synthesis by flow methods, is described. Some examples of flow "fine" synthesis of natural products and APIs are discussed. Flow methods have several advantages over batch methods in terms of environmental compatibility, efficiency, and safety. However, synthesis by flow methods is more difficult than synthesis by batch methods. Indeed, it has been considered that synthesis by flow methods can be applicable for the production of simple gasses but that it is difficult to apply to the synthesis of complex molecules such as natural products and APIs. Therefore, organic synthesis of such complex molecules has been conducted by batch methods. On the other hand, syntheses and reactions that attain high yields and high selectivities by flow methods are increasingly reported. Flow methods are leading candidates for the next generation of manufacturing methods that can mitigate environmental concerns toward sustainable society.

  14. Criterion for Identifying Vortices in High-Pressure Flows

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Okong'o, Nora

    2007-01-01

    A study of four previously published computational criteria for identifying vortices in high-pressure flows has led to the selection of one of them as the best. This development can be expected to contribute to understanding of high-pressure flows, which occur in diverse settings, including diesel, gas turbine, and rocket engines and the atmospheres of Jupiter and other large gaseous planets. Information on the atmospheres of gaseous planets consists mainly of visual and thermal images of the flows over the planets. Also, validation of recently proposed computational models of high-pressure flows entails comparison with measurements, which are mainly of visual nature. Heretofore, the interpretation of images of high-pressure flows to identify vortices has been based on experience with low-pressure flows. However, high-pressure flows have features distinct from those of low-pressure flows, particularly in regions of high pressure gradient magnitude caused by dynamic turbulent effects and by thermodynamic mixing of chemical species. Therefore, interpretations based on low-pressure behavior may lead to misidentification of vortices and other flow structures in high-pressure flows. The study reported here was performed in recognition of the need for one or more quantitative criteria for identifying coherent flow structures - especially vortices - from previously generated flow-field data, to complement or supersede the determination of flow structures by visual inspection of instantaneous fields or flow animations. The focus in the study was on correlating visible images of flow features with various quantities computed from flow-field data.

  15. EUROarray human papillomavirus (HPV) assay is highly concordant with other commercial assays for detection of high-risk HPV genotypes in women with high grade cervical abnormalities.

    PubMed

    Cornall, A M; Poljak, M; Garland, S M; Phillips, S; Machalek, D A; Tan, J H; Quinn, M A; Tabrizi, S N

    2016-06-01

    The purpose of this study was to evaluate the performance of the EUROIMMUN EUROArray HPV genotyping assay against the Roche Cobas 4800, Roche HPV Amplicor, Roche Linear Array and Qiagen Hybrid Capture 2 assays in the detection of high-risk HPV (HR-HPV) from liquid based cervical cytology samples collected from women undergoing follow-up for abnormal cervical cytology results. Cervical specimens from 404 women undergoing management of high-grade cytological abnormality were evaluated by EUROarray HPV for detection of HR-HPV genotypes and prediction of histologically-confirmed cervical intraepithelial neoplasia grade 2 or higher (≥CIN2). The results were compared to Hybrid Capture 2, Cobas 4800 HPV, Amplicor and Linear Array HPV. Positivity for 14 HR-HPV types was 80.0 % for EUROarray (95 % CI; 75.7-83.8 %). Agreement (κ, 95 % CI) between the EUROarray and other HPV tests for detection of HR-HPV was good to very good [Hybrid Capture κ = 0.62 (0.54-0.71); Cobas κ = 0.81 (0.74-0.88); Amplicor κ = 0.68 (0.60-0.77); Linear Array κ = 0.77 (0.70-0.85)]. For detection of HR-HPV, agreement with EUROarray was 87.90 % (Hybrid Capture), 93.58 % (Cobas), 92.84 % (Amplicor) and 92.59 % (Linear Array). Detection of HR-HPV was not significantly different between EUROarray and any other test (p < 0.001). EUROarray was concordant with other assays evaluated for detection of high-risk HPV and showed sensitivity and specificity for detection of ≥ CIN2 of 86 % and 71 %, respectively. PMID:27048314

  16. Addressing the Uncertainty in Prescribing High Flows for River Restoration

    NASA Astrophysics Data System (ADS)

    Downs, P. W.; Sklar, L.; Braudrick, C. A.

    2002-12-01

    Flow prescriptions for environmental benefit in regulated rivers are commonly focused on the provision of minimum flow depths to achieve fish passage and holding habitat objectives. Assessment of these flows can be achieved readily and with reasonable confidence by using low-flow hydrological records and channel morphology data in combination with one dimensional hydraulic modeling. More recently, as understanding has increased of the critical role played by high flows in maintaining a wide range of habitats for instream and riparian flora and fauna, attention has turned to prescribing high flows to invoke the geomorphic processes that maintain suitable habitat niches. Prediction of the effects of these flows may require high-flow discharge and sediment transport data, high resolution topographic data, hydraulic and sediment transport modeling (often in two or three spatial dimensions), knowledge of the watershed historical context, and an understanding of the thresholds for channel morphological change. Not surprisingly, the associated level of uncertainty in this analysis increases tremendously. High flows are defined by a combination of magnitude, frequency, timing and duration parameters and their impact varies according to antecedent events. High flow bedload sediment transport records are rare, sediment transport equations are reliable usually to only an order of magnitude, practical applications of two and three-dimensional sediment transport models are in their infancy, the watershed historical record may be patchy with the link between cause and effect difficult to ascertain, and thresholds of channel morphological change are poorly understood. As the first step in reducing uncertainty, it is essential to state precisely the ecological target objectives of prescribed high flows, and to link these objectives to the hydraulic and geomorphic thresholds to be achieved or exceeded. Such thresholds provide the basis for a systematic classification of high flows

  17. [History of high-flow priapism: 1960-2005].

    PubMed

    Engel, O; Bartsch, G; Küfer, R; Braun, C; Hautmann, R E; Volkmer, B G

    2006-03-01

    High-flow priapism caused by a pathological arterial influx to the cavernous bodies was first described by F.B. Burt in 1960. The pathophysiological differentiation of high- and low-flow priapism was developed in 1983. The development of diagnostic tools for differentiation of different forms of priapism and the progress in the therapy of high-flow priapism from arterial ligation to supraselective embolization is presented. PMID:16307222

  18. High-density turbidity currents: Are they sandy debris flows?

    SciTech Connect

    Shanmugam, G.

    1996-01-01

    Conventionally, turbidity currents are considered as fluidal flows in which sediment is supported by fluid turbulence, whereas debris flows are plastic flows in which sediment is supported by matrix strength, dispersive pressure, and buoyant lift. The concept of high-density turbidity current refers to high-concentration, commonly non-turbulent, flows of fluids in which sediment is supported mainly by matrix strength, dispersive pressure, and buoyant lift. The conventional wisdom that traction carpets with entrained turbulent clouds on top represent high-density turbidity currents is a misnomer because traction carpets are neither fluidal nor turbulent. Debris flows may also have entrained turbulent clouds on top. The traction carpet/debris flow and the overriding turbulent clouds are two separate entities in terms of flow rheology and sediment-support mechanism. In experimental and theoretical studies, which has linked massive sands and floating clasts to high-density turbidity currents, the term high-density turbidity current has actually been used for laminar flows. In alleviating this conceptual problem, sandy debris flow is suggested as a substitute for high-density turbidity current. Sandy debris flows represent a continuous spectrum of processes between cohesive and cohesionless debris flows. Commonly they are rheologically plastic. They may occur with or without entrained turbulent clouds on top. Their sediment-support mechanisms include matrix strength, dispersive pressure, and buoyant lift. They are characterized by laminar flow conditions, a moderate to high grain concentration, and a low to moderate mud content. Although flows evolve and transform during the course of transport in density-stratified flows, the preserved features in a deposit are useful to decipher only the final stages of deposition. At present, there are no established criteria to decipher transport mechanism from the depositional record.

  19. 'Abnormal' angle response curves of TW/Rs for near zero tilt and high tilt channeling implants

    SciTech Connect

    Guo Baonian; Gossmann, Hans-Joachim; Toh, Terry; Colombeau, Benjamin; Todorov, Stan; Sinclair, Frank; Shim, Kyu-Ha; Henry, Todd

    2012-11-06

    Angle control has been widely accepted as the key requirement for ion implantation in semiconductor device processing. From an ion implanter point of view, the incident ion direction should be measured and corrected by suitable techniques, such as XP-VPS for the VIISta implanter platform, to ensure precision ion placement in device structures. So called V-curves have been adopted to generate the wafer-based calibration using channeling effects as the Si lattice steer ions into a channeling direction. Thermal Wave (TW) or sheet resistance (Rs) can be used to determine the minimum of the angle response curve. Normally it is expected that the TW and Rs have their respective minima at identical angles. However, the TW and Rs response to the angle variations does depend on factors such as implant species, dose, and wafer temperature. Implant damage accumulation effects have to be considered for data interpretation especially for some 'abnormal' V-curve data. In this paper we will discuss some observed 'abnormal' angle responses, such as a) TW/Rs reverse trend for Arsenic beam, 2) 'W' shape of Rs Boron, and 3) apparent TW/Rs minimum difference for high tilt characterization, along with experimental data and TCAD simulations.

  20. Distinct Patterns of Grey Matter Abnormality in High-Functioning Autism and Asperger's Syndrome

    ERIC Educational Resources Information Center

    McAlonan, Grainne M.; Suckling, John; Wong, Naikei; Cheung, Vinci; Lienenkaemper, Nina; Cheung, Charlton; Chua, Siew E.

    2008-01-01

    Background: Autism exists across a wide spectrum and there is considerable debate as to whether children with Asperger's syndrome, who have normal language milestones, should be considered to comprise a subgroup distinct other from high-functioning children with autism (HFA), who have a history of delayed language development. Magnetic resonance…

  1. Chromium (D-phenylalanine)3 alleviates high fat-induced insulin resistance and lipid abnormalities.

    PubMed

    Kandadi, Machender Reddy; Unnikrishnan, M K; Warrier, Ajaya Kumar Sankara; Du, Min; Ren, Jun; Sreejayan, Nair

    2011-01-01

    High-fat diet has been implicated as a major cause of insulin resistance and dyslipidemia. The objective of this study was to evaluate the impact of dietary-supplementation of chromium (D-phenylalanine)(3) [Cr(D-Phe)(3)] on glucose and insulin tolerance in high-fat diet fed mice. C57BL/6-mice were randomly assigned to orally receive vehicle or Cr(D-Phe)(3) (45 μg of elemental chromium/kg/day) for 8-weeks. High-fat-fed mice exhibited impaired whole-body-glucose and -insulin tolerance and elevated serum triglyceride levels compared to normal chow-fed mice. Insulin-stimulated glucose up-take in the gastrocnemius muscles, assessed as 2-[(3)H-deoxyglucose] incorporation was markedly diminished in high-fat fed mice compared to control mice. Treatment with chromium reconciled the high-fat diet-induced alterations in carbohydrate and lipid metabolism. Treatment of cultured, differentiated myotubes with palmitic acid evoked insulin resistance as evidenced by lower levels of insulin-stimulated Akt-phosphorylation, elevated JNK-phosphorylation, (assessed by Western blotting), attenuation of phosphoinositol-3-kinase activity (determined in the insulin-receptor substrate-1-immunoprecipitates by measuring the extent of phosphorylation of phosphatidylinositol by γ-(32)P-ATP), and impairment in cellular glucose up-take, all of which were inhibited by Cr(d-Phe)(3). These results suggest a beneficial effect of chromium-supplementation in insulin resistant conditions. It is likely that these effects of chromium may be mediated by augmenting downstream insulin signaling.

  2. 5. GORGE HIGH DAM; LOOKING TOWARD INTAKE WITH WATER FLOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. GORGE HIGH DAM; LOOKING TOWARD INTAKE WITH WATER FLOWING OVER THE TOP OF THE SPILLGATE, 1989. - Skagit Power Development, Gorge High Dam, On Skagit River, 2.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  3. Behavioral and neurochemical abnormalities after exposure to low doses of high-energy iron particles

    NASA Astrophysics Data System (ADS)

    Hunt, Walter A.; Joseph, James A.; Rabin, Bernard M.

    Exposure of rats to high-energy iron particles (600 MeV/amu) has been found to alter behavior after doses as low as 10 rads. The performance of a task that measures upper body strength was significantly degraded after irradiation. In addition, an impairment in the regulation of dopamine release in the caudate nucleus (a motor center in the brain), lasting at least 6 months, was also found and correlated with the performance deficits. A general indication of behavioral toxicity and an index of nausea and emesis, the conditioned taste aversion, was also evident. The sensitivity to iron particles was 10-600 times greater than to gamma photons. These results suggest that behavioral and neurobiological damage may be a consequence of exposure to low doses of heavy particles and that this possibility should be extensively studied.

  4. Behavioral and neurochemical abnormalities after exposure to low doses of high-energy iron particles

    SciTech Connect

    Hunt, W.A.; Joseph, J.A.; Rabin, B.M.

    1989-01-01

    Exposure of rats to high-energy iron particles (600 MeV/amu) has been found to alter behavior after doses as low as 10 rads. The performance of a task that measures upper body strength was significantly degraded after irradiation. In addition, an impairment in the regulation of dopamine release in the caudate nucleus (a motor center in the brain), lasting at least 6 months, was also found and correlated with the performance deficits. A general indication of behavioral toxicity and an index of nausea and emesis, the conditioned taste aversion, was also evident. The sensitivity to iron particles was 10-600 times greater than to gamma photons. These results suggest that behavioral and neurobiological damage may be a consequence of exposure to low doses of heavy particles and that this possibility should be extensively studied.

  5. Case Report: Conversion of a Low-Flow to High-Flow Priapism.

    PubMed

    Cahn, David; Courter, Elliot; Diorio, Gregory; Metro, Michael; Ginsberg, Phillip

    2015-07-01

    Priapism is defined as an erection lasting for more than 4 hours and can be grouped into 3 distinct subtypes: ischemic (low-flow), stuttering and non-ischemic (high-flow). Herein, we present an interesting case of conversion from a low-flow to high-flow priapism after a distal shunting procedure. This is a rare phenomenon that has a paucity of documented cases. Diagnosis requires prompt clinical suspicion and confirmatory testing including penile cavernosal blood gases and Doppler ultrasound. PMID:26889126

  6. Sasa quelpaertensis leaf extract improves high fat diet-induced lipid abnormalities and regulation of lipid metabolism genes in rats.

    PubMed

    Kim, Jina; Kim, Yoo-Sun; Lee, Hyun Ah; Lim, Ji Ye; Kim, Mina; Kwon, Oran; Ko, Hee-Chul; Kim, Se-Jae; Shin, Jae-Ho; Kim, Yuri

    2014-05-01

    Sasa quelpaertensis is a bamboo leaf that is only grown on Jeju Island in South Korea. It is used as a bamboo tea that is consumed for therapeutic purposes, particularly for its anti-diabetic, diuretic, and anti-inflammatory effects. This study investigated the effect of S. quelpaertensis leaf extract (SQE) on high fat-induced lipid abnormalities and regulation of lipid metabolism-related gene expressions in rats. SQE supplementation significantly decreased the levels of plasma triglycerides, total cholesterol, and low-density lipoprotein cholesterol as well as the atherogenic index. SQE restored levels of plasma high-density lipoprotein cholesterol, which were lowered by a high fat diet. Plasma and cardiac resistin levels were also significantly decreased by SQE supplementation. In adipose tissue, mRNA levels of CAAT/enhancer-binding protein β (C/EBPβ) were suppressed in the SQE group. SQE supplementation decreased the accumulation of lipid droplets, inflammatory cell infiltrations, levels of triglycerides, and total lipids in the liver and effectively down-regulated expression of sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthetase (FAS), and uncoupling protein 2 (UCP-2). These results suggest that SQE may be a potential treatment for high fat-related disorders by improving lipid profiles and modulating lipid metabolism.

  7. Reversible Brain Abnormalities in People Without Signs of Mountain Sickness During High-Altitude Exposure

    PubMed Central

    Fan, Cunxiu; Zhao, Yuhua; Yu, Qian; Yin, Wu; Liu, Haipeng; Lin, Jianzhong; Yang, Tianhe; Fan, Ming; Gesang, Luobu; Zhang, Jiaxing

    2016-01-01

    A large proportion of lowlanders ascending to high-altitude (HA) show no signs of mountain sickness. Whether their brains have indeed suffered from HA environment and the persistent sequelae after return to lowland remain unknown. Thirty-one sea-level college students, who had a 30-day teaching on Qinghai-Tibet plateau underwent MRI scans before, during, and two months after HA exposure. Brain volume, cortical structures, and white matter microstructure were measured. Besides, serum neuron-specific enolase (NSE), C-reactive protein, and interleukin-6 and neuropsychiatric behaviors were tested. After 30-day HA exposure, the gray and white matter volumes and cortical surface areas significantly increased, with cortical thicknesses and curvatures changed in a wide spread regions; Anisotropy decreased with diffusivities increased in multiple sites of white matter tracts. Two months after HA exposure, cortical measurements returned to basal level. However, increased anisotropy with decreased diffusivities was observed. Behaviors and serum inflammatory factor did not significant changed during three time-point tests. NSE significantly decreased during HA but increased after HA exposure. Results suggest brain swelling occurred in people without neurological signs at HA, but no negative sequelae in cortical structures and neuropsychiatric functions were left after the return to lowlands. Reoxygenation changed white matter microstructure. PMID:27633944

  8. A tyrosinase with an abnormally high tyrosine hydroxylase/dopa oxidase ratio.

    PubMed

    Hernández-Romero, Diana; Sanchez-Amat, Antonio; Solano, Francisco

    2006-01-01

    The sequencing of the genome of Ralstonia solanacearum[Salanoubat M, Genin S, Artiguenave F, et al. (2002) Nature 415, 497-502] revealed several genes that putatively code for polyphenol oxidases (PPOs). This soil-borne pathogenic bacterium withers a wide range of plants. We detected the expression of two PPO genes (accession numbers NP_518458 and NP_519622) with high similarity to tyrosinases, both containing the six conserved histidines required to bind the pair of type-3 copper ions at the active site. Generation of null mutants in those genes by homologous recombination mutagenesis and protein purification allowed us to correlate each gene with its enzymatic activity. In contrast with all tyrosinases so far studied, the enzyme NP_518458 shows higher monophenolase than o-diphenolase activity and its initial activity does not depend on the presence of l-dopa cofactor. On the other hand, protein NP_519622 is an enzyme with a clear preference to oxidize o-diphenols and only residual monophenolase activity, behaving as a catechol oxidase. These catalytic characteristics are discussed in relation to two other characteristics apart from the six conserved histidines. One is the putative presence of a seventh histidine which interacts with the carboxy group on the substrate and controls the preference for carboxylated and decarboxylated substrates. The second is the size of the residue isosteric with the aromatic F261 reported in sweet potato catechol oxidase which acts as a gate to control accessibility to CuA at the active site. PMID:16403014

  9. Reversible Brain Abnormalities in People Without Signs of Mountain Sickness During High-Altitude Exposure.

    PubMed

    Fan, Cunxiu; Zhao, Yuhua; Yu, Qian; Yin, Wu; Liu, Haipeng; Lin, Jianzhong; Yang, Tianhe; Fan, Ming; Gesang, Luobu; Zhang, Jiaxing

    2016-01-01

    A large proportion of lowlanders ascending to high-altitude (HA) show no signs of mountain sickness. Whether their brains have indeed suffered from HA environment and the persistent sequelae after return to lowland remain unknown. Thirty-one sea-level college students, who had a 30-day teaching on Qinghai-Tibet plateau underwent MRI scans before, during, and two months after HA exposure. Brain volume, cortical structures, and white matter microstructure were measured. Besides, serum neuron-specific enolase (NSE), C-reactive protein, and interleukin-6 and neuropsychiatric behaviors were tested. After 30-day HA exposure, the gray and white matter volumes and cortical surface areas significantly increased, with cortical thicknesses and curvatures changed in a wide spread regions; Anisotropy decreased with diffusivities increased in multiple sites of white matter tracts. Two months after HA exposure, cortical measurements returned to basal level. However, increased anisotropy with decreased diffusivities was observed. Behaviors and serum inflammatory factor did not significant changed during three time-point tests. NSE significantly decreased during HA but increased after HA exposure. Results suggest brain swelling occurred in people without neurological signs at HA, but no negative sequelae in cortical structures and neuropsychiatric functions were left after the return to lowlands. Reoxygenation changed white matter microstructure. PMID:27633944

  10. Importance of considering intraborehole flow in solute transport modeling under highly dynamic flow conditions.

    PubMed

    Ma, Rui; Zheng, Chunmiao; Tonkin, Matt; Zachara, John M

    2011-04-01

    Correct interpretation of tracer test data is critical for understanding transport processes in the subsurface. This task can be greatly complicated by the presence of intraborehole flows in a highly dynamic flow environment. At a new tracer test site (Hanford IFRC) a dynamic flow field created by changes in the stage of the adjacent Columbia River, coupled with a heterogeneous hydraulic conductivity distribution, leads to considerable variations in vertical hydraulic gradients. These variations, in turn, create intraborehole flows in fully-screened (6.5m) observation wells with frequently alternating upward and downward movement. This phenomenon, in conjunction with a highly permeable aquifer formation and small horizontal hydraulic gradients, makes modeling analysis and model calibration a formidable challenge. Groundwater head data alone were insufficient to define the flow model boundary conditions, and the movement of the tracer was highly sensitive to the dynamics of the flow field. This study shows that model calibration can be significantly improved by explicitly considering (a) dynamic flow model boundary conditions and (b) intraborehole flow. The findings from this study underscore the difficulties in interpreting tracer tests and understanding solute transport under highly dynamic flow conditions. PMID:21216023

  11. Importance of considering intraborehole flow in solute transport modeling under highly dynamic flow conditions

    SciTech Connect

    Ma, Rui; Zheng, Chunmiao; Tonkin, Matthew J.; Zachara, John M.

    2011-04-01

    Correct interpretation of tracer test data is critical for understanding transport processes in the subsurface. This task can be greatly complicated by the presence of intraborehole flows in a highly dynamic flow environment. At a new tracer test site (Hanford IFRC) a dynamic flow field created by changes in the stage of the adjacent Columbia River, coupled with a heterogeneous hydraulic conductivity distribution, leads to considerable variations in vertical hydraulic gradients. These variations, in turn, create intraborehole flows in fully-screened (6.5 m) observation wells with frequently alternating upward and downward movement. This phenomenon, in conjunction with a highly permeable aquifer formation and small horizontal hydraulic gradients, makes modeling analysis and model calibration a formidable challenge. Groundwater head data alone were insufficient to define the flow model boundary conditions, and the movement of the tracer was highly sensitive to the dynamics of the flow field. This study shows that model calibration can be significantly improved by explicitly considering (a) dynamic flow model boundary conditions and (b) intraborehole flow. The findings from this study underscore the difficulties in interpreting tracer tests and understanding solute transport under highly dynamic flow conditions.

  12. Influence of abnormally high leptin levels during pregnancy on metabolic phenotypes in progeny mice.

    PubMed

    Makarova, Elena N; Chepeleva, Elena V; Panchenko, Polina E; Bazhan, Nadezhda M

    2013-12-01

    Maternal obesity increases the risk of obesity in offspring, and obesity is accompanied by an increase in blood leptin levels. The "yellow" mutation at the mouse agouti locus (A(y)) increases blood leptin levels in C57BL preobese pregnant mice without affecting other metabolic characteristics. We investigated the influence of the A(y) mutation or leptin injection at the end of pregnancy in C57BL mice on metabolic phenotypes and the susceptibility to diet-induced obesity (DIO) in offspring. In both C57BL-A(y) and leptin-treated mice, the maternal effect was more pronounced in male offspring. Compared with males born to control mothers, males born to A(y) mothers displayed equal food intake (FI) but decreased body weight (BW) gain after weaning, equal glucose tolerance, and enhanced FI-to-BW ratios on the standard diet but the same FI and BW on the high-fat diet. Males born to A(y) mothers were less responsive to the anorectic effect of exogenous leptin and less resistant to fasting (were not hyperphagic and gained less weight during refeeding after food deprivation) compared with males born to control mothers. However, all progeny displayed equal hypothalamic expression of Agouti gene-related protein (AgRP), neuropeptide Y (NPY), and proopiomelanocortin (POMC) and equal plasma leptin and glucose levels after food deprivation. Leptin injections in C57BL mice on day 17 of pregnancy decreased BW in both male and female offspring but inhibited FI and DIO only in male offspring. Our results show that hyperleptinemia during pregnancy has sex-specific long-term effects on energy balance regulation in progeny and does not predispose offspring to developing obesity.

  13. Highly simplified lateral flow-based nucleic acid sample preparation and passive fluid flow control

    DOEpatents

    Cary, Robert E.

    2015-12-08

    Highly simplified lateral flow chromatographic nucleic acid sample preparation methods, devices, and integrated systems are provided for the efficient concentration of trace samples and the removal of nucleic acid amplification inhibitors. Methods for capturing and reducing inhibitors of nucleic acid amplification reactions, such as humic acid, using polyvinylpyrrolidone treated elements of the lateral flow device are also provided. Further provided are passive fluid control methods and systems for use in lateral flow assays.

  14. High speed digital holographic interferometry for hypersonic flow visualization

    NASA Astrophysics Data System (ADS)

    Hegde, G. M.; Jagdeesh, G.; Reddy, K. P. J.

    2013-06-01

    Optical imaging techniques have played a major role in understanding the flow dynamics of varieties of fluid flows, particularly in the study of hypersonic flows. Schlieren and shadowgraph techniques have been the flow diagnostic tools for the investigation of compressible flows since more than a century. However these techniques provide only the qualitative information about the flow field. Other optical techniques such as holographic interferometry and laser induced fluorescence (LIF) have been used extensively for extracting quantitative information about the high speed flows. In this paper we present the application of digital holographic interferometry (DHI) technique integrated with short duration hypersonic shock tunnel facility having 1 ms test time, for quantitative flow visualization. Dynamics of the flow fields in hypersonic/supersonic speeds around different test models is visualized with DHI using a high-speed digital camera (0.2 million fps). These visualization results are compared with schlieren visualization and CFD simulation results. Fringe analysis is carried out to estimate the density of the flow field.

  15. High energy density redox flow device

    DOEpatents

    Chiang, Yet -Ming; Carter, W. Craig; Duduta, Mihai; Limthongkul, Pimpa

    2015-10-06

    Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.

  16. High energy density redox flow device

    DOEpatents

    Chiang, Yet-Ming; Carter, William Craig; Duduta, Mihai; Limthongkul, Pimpa

    2014-05-13

    Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.

  17. High Fidelity Simulations of Unsteady Flow through Turbopumps and Flowliners

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin C.; Kwak, dochan; Chan, William; Housman, Jeff

    2006-01-01

    High fidelity computations were carried out to analyze the orbiter LH2 feedline flowliner. Computations were performed on the Columbia platform which is a 10,240-processor supercluster consisting of 20 Altix nodes with 512 processor each. Various computational models were used to characterize the unsteady flow features in the turbopump, including the orbiter Low-Pressure-Fuel-Turbopump (LPFTP) inducer, the orbiter manifold and a test article used to represent the manifold. Unsteady flow originating from the orbiter LPFTP inducer is one of the major contributors to the high frequency cyclic loading that results in high cycle fatigue damage to the gimbal flowliners just upstream of the LPFTP. The flow fields for the orbiter manifold and representative test article are computed and analyzed for similarities and differences. The incompressible Navier-Stokes flow solver INS3D, based on the artificial compressibility method, was used to compute the flow of liquid hydrogen in each test article.

  18. A Methodology to Detect Abnormal Relative Wall Shear Stress on the Full Surface of the Thoracic Aorta Using 4D Flow MRI

    PubMed Central

    van Ooij, Pim; Potters, Wouter V.; Nederveen, Aart J.; Allen, Bradley D.; Collins, Jeremy; Carr, James; Malaisrie, S. Chris; Markl, Michael; Barker, Alex J.

    2014-01-01

    Purpose To compute cohort-averaged wall shear stress (WSS) maps in the thoracic aorta of patients with aortic dilatation or valvular stenosis and to detect abnormal regional WSS. Methods Systolic WSS vectors, estimated from 4D flow MRI data, were calculated along the thoracic aorta lumen in 10 controls, 10 patients with dilated aortas and 10 patients with aortic valve stenosis. 3D segmentations of each aorta were co-registered by group and used to create a cohort-specific aortic geometry. The WSS vectors of each subject were interpolated onto the corresponding cohort-specific geometry to create cohort-averaged WSS maps. A Wilcoxon rank sum test was used to generate aortic P-value maps (P<0.05) representing regional relative WSS differences between groups. Results Cohort-averaged systolic WSS maps and P-value maps were successfully created for all cohorts and comparisons. The dilation cohort showed significantly lower WSS on 7% of the ascending aorta surface, whereas the stenosis cohort showed significantly higher WSS aorta on 34% the ascending aorta surface. Conclusions The findings of this study demonstrated the feasibility of generating cohort-averaged WSS maps for the visualization and identification of regionally altered WSS in the presence of disease, as compared to healthy controls. PMID:24753241

  19. Superselective Embolization with Coils in High-Flow Priapism

    SciTech Connect

    Kress, Oliver; Heidenreich, A.; Klose, Klaus Jochen; Wagner, Hans-Joachim; Alfke, Heiko

    2002-08-15

    Priapism can be divided into 'low-flow' veno-occlusive priapism and, especially in children, rare 'high-flow' arterial priapism. We report a 5-year-old boy who developed arterial priapism after blunt perineal trauma that was successfully treated by superselective embolization with microcoils.

  20. Numerical Simulation of High-Speed Turbulent Reacting Flows

    NASA Technical Reports Server (NTRS)

    Givi, P.; Taulbee, D. B.; Madnia, C. K.; Jaberi, F. A.; Colucci, P. J.; Gicquel, L. Y. M.; Adumitroaie, V.; James, S.

    1999-01-01

    The objectives of this research are: (1) to develop and implement a new methodology for large eddy simulation of (LES) of high-speed reacting turbulent flows. (2) To develop algebraic turbulence closures for statistical description of chemically reacting turbulent flows.

  1. Analysis of high speed flow, thermal and structural interactions

    NASA Technical Reports Server (NTRS)

    Thornton, Earl A.

    1994-01-01

    Research for this grant focused on the following tasks: (1) the prediction of severe, localized aerodynamic heating for complex, high speed flows; (2) finite element adaptive refinement methodology for multi-disciplinary analyses; (3) the prediction of thermoviscoplastic structural response with rate-dependent effects and large deformations; (4) thermoviscoplastic constitutive models for metals; and (5) coolant flow/structural heat transfer analyses.

  2. Collapse in High-Grade Stenosis during Pulsatile Flow Experiments

    NASA Astrophysics Data System (ADS)

    Kobayashi, Shunichi; Tang, Dalin; Ku, David N.

    It has been hypothesized that blood flow through high grade stenotic arteries may produce conditions in which elastic flow choking may occur. The development of atherosclerotic plaque fracture may be exacerbated by the compressive stresses during collapse. This study explored the effects of pulsatile flow on stenotic flow collapse. Pulsatile flow was produced using a gear pump controlled by a digitized physiologic waveform. Upstream and downstream mean pressures and pulsatile flow rates were measured and digitized. An improved model of arterial stenosis was created using an elastomer with an incremental modulus of elasticity matched to a bovine carotid artery in the relevant range of collapse. Additionally, the model retained a very thick wall in the stenotic region similar to arterial disease. Flow choking was observed for pulsatile pressure drops close to those previously reported for steady flow. The phase difference between flow rate and pressure between upstream and downstream of the stenosis occurred by the compliance of tube and stenosis resistance. For 80% nominal stenosis by diameter and 100+/-30mmHg upstream pressure, collapse occurred for average pulsatile pressure drops of 93mmHg. Pulsatile flow experiments in this model revealed the range of conditions for the flow choking and the paradoxical collapse of the stenosis during systole with expansion during diastole. The stenosis severity was dynamic through the pulse cycle and was significantly greater under flow than the nominal severity. The results indicate that flow choking and stenotic compression may be significant in thick-walled arterial stenoses subjected to pulsatile flow.

  3. Prevalence of abnormal ECGs in male soccer players decreases with the Seattle criteria, but is still high.

    PubMed

    Berge, H M; Gjesdal, K; Andersen, T E; Solberg, E E; Steine, K

    2015-08-01

    Electrocardiogram (ECG) and echocardiography are mandatory in preparticipation cardiac screening in soccer players. Abnormal ECG findings usually require follow-up investigations. The main aim of this study was to compare the prevalence of abnormal ECG findings in male professional soccer players according to European Society of Cardiology's (ESC) recommendations and the Seattle criteria, and to assess the need for echocardiography. ECGs from 587 of 595 (99%) players were recorded with ClickECG, and measurements were derived with visually adjusted on-screen calipers on the computer-based averaged PQRST complex. Echocardiographic recordings were performed with Vivid 7/i and categorized according to reference values for athlete's heart. After the initial screening, 32 (5.5%) players were recommended for follow-up. The prevalence of abnormal ECGs was 29.3% vs 11.2% according to the ESC's recommendations and the Seattle criteria, respectively. None of the players with abnormal ECGs only according to the ESC's recommendations had abnormal echocardiograms. Echocardiography alone detected one player with abnormalities (athlete's heart). The Seattle criteria reduced the number of athletes with abnormal ECGs considerably compared with the ESC recommendations. Based on echocardiographic evaluations, this increased the specificity of the Seattle criteria, without increasing the number of false-negative ECGs. The need for mandatory echocardiography in soccer players seems limited.

  4. Flow mechanism of Forchheimer's cubic equation in high-velocity radial gas flow through porous media

    SciTech Connect

    Ezeudembah, A.S.; Dranchuk, P.M.

    1982-01-01

    Formal derivation of Forchheimer's cubic equation is made by considering the kinetic energy equation of mean flow and dimensional relations for one-dimensional, linear, incompressible fluid flow. By the addition of the cubic term, this equation is regarded as a modified Forchheimer's quadratic equation which accounts for the flow rates obtained beyond the laminar flow condition. The cubic equation spans a wide range of flow rates and regimes. For suitable use in gas flow studies, this equation has been adapted, modified, and corrected for the gas slippage effect. The physical basis of the cubic term has been established by using boundary layer theory to explain the high-velocity, high-pressure flow behavior through a porous path. Gamma, the main parameter in the cubic term, is related directly to a characteristic, dimensionless shape factor which is significant at higher flow rates. It is inversely related to viscosity, but has no dependence on the gas slippage coefficient in the higher flow regime. 25 references.

  5. Stereoscopic PIV measurements of flow in the nasal cavity with high flow therapy

    NASA Astrophysics Data System (ADS)

    Spence, C. J. T.; Buchmann, N. A.; Jermy, M. C.; Moore, S. M.

    2011-04-01

    Knowledge of the airflow characteristics within the nasal cavity with nasal high flow (NHF) therapy and during unassisted breathing is essential to understand the treatment's efficacy. The distribution and velocity of the airflow in the nasal cavity with and without NHF cannula flow has been investigated using stereoscopic particle image velocimetry at steady peak expiration and inspiration. In vivo breathing flows were measured and dimensionally scaled to reproduce physiological conditions in vitro. A scaled model of the complete nasal cavity was constructed in transparent silicone and airflow simulated with an aqueous glycerine solution. NHF modifies nasal cavity flow patterns significantly, altering the proportion of inspiration and expiration through each passageway and producing jets with in vivo velocities up to 17.0 ms-1 for 30 l/min cannula flow. Velocity magnitudes differed appreciably between the left and right sides of the nasal cavity. The importance of using a three-component measurement technique when investigating nasal flows has been highlighted.

  6. High Pressure Reverse Flow APS Engine

    NASA Technical Reports Server (NTRS)

    Senneff, J. M.

    1972-01-01

    A design and test demonstration effort was undertaken to evaluate the concept of the reverse flow engine for the APS engine application. The 1500 lb (6672 N) thrust engine was designed to operate on gaseous hydrogen and gaseous oxygen propellants at a mixture ratio of 4 and to achieve the objective performance of 435 sec (4266 Nsec/kg) specific impulse. Superimposed durability requirements called for a million-cycle capability with 50 hours duration. The program was undertaken as a series of tasks including the initial preliminary design, design of critical test components and finally, the design and demonstration of an altitude engine which could be used interchangeably to examine operating parameters as well as to demonstrate the capability of the concept. The program results are reported with data to indicate that all of the program objectives were met or exceeded within the course of testing on the program. The analysis effort undertaken is also reported in detail and supplemented with test data in some cases where prior definitions could not be made. The results are contained of these analyses as well as the test results conducted throughout the course of the program. Finally, the test data and analytical results were combined to allow recommendations for a flight weight design. This preliminary design effort is also detailed.

  7. Diagnostic accuracy of myocardial deformation indices for detecting high risk coronary artery disease in patients without regional wall motion abnormality

    PubMed Central

    Rostamzadeh, Alireza; Shojaeifard, Maryam; Rezaei, Yousef; Dehghan, Kasra

    2015-01-01

    Background: The prediction of coronary artery disease (CAD) by conventional echocardiographic measurements is principally based on the estimation of ejection fraction and regional wall motion abnormality (RWMA). This study aimed to determine whether strain echocardiography of left ventricle measured by velocity vector imaging (VVI) method could detect patients with a high-risk CAD. Methods: In a prospective study, a total of 119 consecutive patients who were assessed for eligibility were categorized into three groups: (1) without CAD as normal (n=59), (2) 1- or 2-vessel disease as low-risk (n=29), and (3) left main and/or 3-vessel disease as high-risk (n=31). The peaks of systolic strain and strain rate from 18 curves of apical views were averaged as global longitudinal strain and strain rate (GLS and GLSR), respectively; the 6 systolic peaks of strain and strain rate at base- and mid-ventricular of short axis views were averaged as mean radial strain rate (MRSR). Results: GLS, GLSR, and basal MRSR of left ventricle were significantly lower in the high-risk group (P=0.047, P=0.004 and P=0.030, respectively). Receiver operating characteristics curve showed that the optimal values of GLS, GLSR, and basal MRSR for detecting the severe CAD were -17%, -1 s-1, and 1.45 s-1 with the sensitivities of 77%, 71%, and 71% and the specificities of 63%, 67%, and 62%, respectively. Conclusion: Decrements in the GLS, GLSR, and basal MRSR of the left ventricle can detect the high-risk CAD cases among patients without RWMA at rest. PMID:26309603

  8. Computational analysis of high-throughput flow cytometry data

    PubMed Central

    Robinson, J Paul; Rajwa, Bartek; Patsekin, Valery; Davisson, Vincent Jo

    2015-01-01

    Introduction Flow cytometry has been around for over 40 years, but only recently has the opportunity arisen to move into the high-throughput domain. The technology is now available and is highly competitive with imaging tools under the right conditions. Flow cytometry has, however, been a technology that has focused on its unique ability to study single cells and appropriate analytical tools are readily available to handle this traditional role of the technology. Areas covered Expansion of flow cytometry to a high-throughput (HT) and high-content technology requires both advances in hardware and analytical tools. The historical perspective of flow cytometry operation as well as how the field has changed and what the key changes have been discussed. The authors provide a background and compelling arguments for moving toward HT flow, where there are many innovative opportunities. With alternative approaches now available for flow cytometry, there will be a considerable number of new applications. These opportunities show strong capability for drug screening and functional studies with cells in suspension. Expert opinion There is no doubt that HT flow is a rich technology awaiting acceptance by the pharmaceutical community. It can provide a powerful phenotypic analytical toolset that has the capacity to change many current approaches to HT screening. The previous restrictions on the technology, based on its reduced capacity for sample throughput, are no longer a major issue. Overcoming this barrier has transformed a mature technology into one that can focus on systems biology questions not previously considered possible. PMID:22708834

  9. Lipid metabolism abnormalities in alcohol-treated rabbits: a morphometric and haematologic study comparing high and low alcohol doses

    PubMed Central

    Ikemura, Satoshi; Yamamoto, Takuaki; Motomura, Goro; Iwasaki, Kenyu; Yamaguchi, Ryosuke; Zhao, Garida; Iwamoto, Yukihide

    2011-01-01

    The pathogenesis of alcohol-induced osteonecrosis remains unclear. The purpose of the present study was to evaluate the morphological changes in bone marrow fat cells and the changes in the serum lipid levels in alcohol-treated rabbits. Fifteen rabbits were randomly assigned into three groups: Four rabbits intragastrically received low-dose alcohol (LDA) (15 ml/kg per day) containing 15% ethanol for 4 weeks, five rabbits received high-dose alcohol (HDA) (30 ml/kg per day) for 4 weeks and six rabbits received physiologic saline for 4 weeks as a control group. Six weeks after the initial alcohol administration, all rabbits were sacrificed. The mean size of the bone marrow fat cells in rabbits treated with HDA was significantly larger than that in the control group (P = 0.0001). Haematologically, the levels of triglycerides and free fatty acids in the rabbits treated with both low-dose and HDA were significantly higher than those in the control group (P = 0.001 for both comparisons). The results of this study are that there are lipid metabolism abnormalities, both morphologically and haematologically, after alcohol administration. Also these findings were more apparent in rabbits treated with HDA than those treated with LDA. PMID:21645143

  10. Abnormal functional specialization within medial prefrontal cortex in high-functioning autism: a multi-voxel similarity analysis

    PubMed Central

    Meuwese, Julia D.I.; Towgood, Karren J.; Frith, Christopher D.; Burgess, Paul W.

    2009-01-01

    Multi-voxel pattern analyses have proved successful in ‘decoding’ mental states from fMRI data, but have not been used to examine brain differences associated with atypical populations. We investigated a group of 16 (14 males) high-functioning participants with autism spectrum disorder (ASD) and 16 non-autistic control participants (12 males) performing two tasks (spatial/verbal) previously shown to activate medial rostral prefrontal cortex (mrPFC). Each task manipulated: (i) attention towards perceptual versus self-generated information and (ii) reflection on another person's mental state (‘mentalizing'versus ‘non-mentalizing’) in a 2 × 2 design. Behavioral performance and group-level fMRI results were similar between groups. However, multi-voxel similarity analyses revealed strong differences. In control participants, the spatial distribution of activity generalized significantly between task contexts (spatial/verbal) when examining the same function (attention/mentalizing) but not when comparing different functions. This pattern was disrupted in the ASD group, indicating abnormal functional specialization within mrPFC, and demonstrating the applicability of multi-voxel pattern analysis to investigations of atypical populations. PMID:19174370

  11. Onset of turbulence in accelerated high-Reynolds-number flow.

    PubMed

    Zhou, Ye; Robey, Harry F; Buckingham, Alfred C

    2003-05-01

    A new criterion, flow drive time, is identified here as a necessary condition for transition to turbulence in accelerated, unsteady flows. Compressible, high-Reynolds-number flows initiated, for example, in shock tubes, supersonic wind tunnels with practical limitations on dimensions or reservoir capacity, and high energy density pulsed laser target vaporization experimental facilities may not provide flow duration adequate for turbulence development. In addition, for critical periods of the overall flow development, the driving background flow is often unsteady in the experiments as well as in the physical flow situations they are designed to mimic. In these situations transition to fully developed turbulence may not be realized despite achievement of flow Reynolds numbers associated with or exceeding stationary flow transitional criteria. Basically our transitional criterion and prediction procedure extends to accelerated, unsteady background flow situations the remarkably universal mixing transition criterion proposed by Dimotakis [P. E. Dimotakis, J. Fluid Mech. 409, 69 (2000)] for stationary flows. This provides a basis for the requisite space and time scaling. The emphasis here is placed on variable density flow instabilities initiated by constant acceleration Rayleigh-Taylor instability (RTI) or impulsive (shock) acceleration Richtmyer-Meshkov instability (RMI) or combinations of both. The significant influences of compressibility on these developing transitional flows are discussed with their implications on the procedural model development. A fresh perspective for predictive modeling and design of experiments for the instability growth and turbulent mixing transitional interval is provided using an analogy between the well-established buoyancy-drag model with applications of a hierarchy of single point turbulent transport closure models. Experimental comparisons with the procedural results are presented where use is made of three distinctly different types

  12. High-Throughput Continuous Flow Production of Nanoscale Liposomes by Microfluidic Vertical Flow Focusing.

    PubMed

    Hood, Renee R; DeVoe, Don L

    2015-11-18

    Liposomes represent a leading class of nanoparticles for drug delivery. While a variety of techniques for liposome synthesis have been reported that take advantage of microfluidic flow elements to achieve precise control over the size and polydispersity of nanoscale liposomes, with important implications for nanomedicine applications, these methods suffer from extremely limited throughput, making them impractical for large-scale nanoparticle synthesis. High aspect ratio microfluidic vertical flow focusing is investigated here as a new approach to overcoming the throughput limits of established microfluidic nanoparticle synthesis techniques. Here the vertical flow focusing technique is utilized to generate populations of small, unilamellar, and nearly monodisperse liposomal nanoparticles with exceptionally high production rates and remarkable sample homogeneity. By leveraging this platform, liposomes with modal diameters ranging from 80 to 200 nm are prepared at production rates as high as 1.6 mg min(-1) in a simple flow-through process.

  13. Turbulent behaviour of non-cohesive sediment gravity flows at unexpectedly high flow density

    NASA Astrophysics Data System (ADS)

    Baker, Megan; Baas, Jaco H.; Malarkey, Jonathan; Kane, Ian

    2016-04-01

    Experimental lock exchange-type turbidity currents laden with non-cohesive silica-flour were found to be highly dynamic at remarkably high suspended sediment concentrations. These experiments were conducted to produce sediment gravity flows of volumetric concentrations ranging from 1% to 52%, to study how changes in suspended sediment concentration affects the head velocities and run-out distances of these flows, in natural seawater. Increasing the volumetric concentration of suspended silica-flour, C, up to C = 46%, within the flows led to a progressive increase in the maximum head velocity. This relationship suggests that suspended sediment concentration intensifies the density difference between the turbulent suspension and the ambient water, which drives the flow, even if almost half of the available space is occupied by sediment particles. However, from C = 46% to C = 52% a rapid reduction in the maximum head velocity was measured. It is inferred that at C = 46%, friction from grain-to-grain interactions begins to attenuate turbulence within the flows. At C > 46%, the frictional stresses become progressively more dominant over the turbulent forces and excess density, thus producing lower maximum head velocities. This grain interaction process started to rapidly reduce the run-out distance of the silica-flour flows at equally high concentrations of C ≥ 47%. All flows with C < 47% reflected off the end of the 5-m long tank, but the head velocities gradually reduced along the tank. Bagnold (1954, 1963) estimated that, for sand flows, grain-to-grain interactions start to become important in modulating turbulence at C > 9%. Yet, the critical flow concentration at which turbulence modulation commenced for these silica-flour laden flows appeared to be much higher. We suggest that Bagnold's 9% criterion cannot be applied to flows that carry fine-grained sediment, because turbulent forces are more important than dispersive forces, and frictional forces start to

  14. Reduction of low- and high-grade cervical abnormalities associated with high uptake of the HPV bivalent vaccine in Scotland

    PubMed Central

    Pollock, K G J; Kavanagh, K; Potts, A; Love, J; Cuschieri, K; Cubie, H; Robertson, C; Cruickshank, M; Palmer, T J; Nicoll, S; Donaghy, M

    2014-01-01

    Background: In Scotland, a national HPV immunisation programme began in 2008 for 12- to 13-year olds, with a catch-up campaign from 2008 to 2011 for those under the age of 18. To monitor the impact of HPV immunisation on cervical disease at the population level, a programme of national surveillance was established. Methods: We analysed colposcopy data from a cohort of women born between 1988 and 1992 who entered the Scottish Cervical Screening Programme (SCSP) and were aged 20–21 in 2008–2012. Results: By linking datasets from the SCSP and colposcopy services, we observed a significant reduction in diagnoses of cervical intraepithelial neoplasia 1 (CIN 1; RR 0.71, 95% CI 0.58 to 0.87; P=0.0008), CIN 2 (RR 0.5, 95% CI 0.4 to 0.63; P<0.0001) and CIN 3 (RR 0.45, 95% CI 0.35 to 0.58; P<0.0001) for women who received three doses of vaccine compared with unvaccinated women. Conclusions: To our knowledge, this is one of the first studies to show a reduction of low- and high-grade CIN associated with high uptake of the HPV bivalent vaccine at the population level. These data are very encouraging for countries that have achieved high HPV vaccine uptake. PMID:25180766

  15. Abnormal White Matter Integrity Related to Head Impact Exposure in a Season of High School Varsity Football

    PubMed Central

    Davenport, Elizabeth M.; Urban, Jillian E.; Espeland, Mark A.; Jung, Youngkyoo; Rosenbaum, Daryl A.; Gioia, Gerard A.; Powers, Alexander K.; Stitzel, Joel D.; Maldjian, Joseph A.

    2014-01-01

    Abstract The aim of this study was to determine whether the cumulative effects of head impacts from a season of high school football produce magnetic resonance imaging (MRI) measureable changes in the brain in the absence of clinically diagnosed concussion. Players from a local high school football team were instrumented with the Head Impact Telemetry System (HITS™) during all practices and games. All players received pre- and postseason MRI, including diffusion tensor imaging (DTI). Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) was also conducted. Total impacts and risk-weighted cumulative exposure (RWE), including linear (RWELinear), rotational (RWERotational), and combined components (RWECP), were computed from the sensor data. Fractional, linear, planar, and spherical anisotropies (FA, CL, CP, and CS, respectively), as well as mean diffusivity (MD), were used to determine total number of abnormal white matter voxels defined as 2 standard deviations above or below the group mean. Delta (post-preseason) ImPACT scores for each individual were computed and compared to the DTI measures using Spearman's rank correlation coefficient. None of the players analyzed experienced clinical concussion (N=24). Regression analysis revealed a statistically significant linear relationship between RWECP and FA. Secondary analyses demonstrated additional statistically significant linear associations between RWE (RWECP and RWELinear) and all DTI measures. There was also a strong correlation between DTI measures and change in Verbal Memory subscore of the ImPACT. We demonstrate that a single season of football can produce brain MRI changes in the absence of clinical concussion. Similar brain MRI changes have been previously associated with mild traumatic brain injury. PMID:24786802

  16. Abnormal white matter integrity related to head impact exposure in a season of high school varsity football.

    PubMed

    Davenport, Elizabeth M; Whitlow, Christopher T; Urban, Jillian E; Espeland, Mark A; Jung, Youngkyoo; Rosenbaum, Daryl A; Gioia, Gerard A; Powers, Alexander K; Stitzel, Joel D; Maldjian, Joseph A

    2014-10-01

    The aim of this study was to determine whether the cumulative effects of head impacts from a season of high school football produce magnetic resonance imaging (MRI) measureable changes in the brain in the absence of clinically diagnosed concussion. Players from a local high school football team were instrumented with the Head Impact Telemetry System (HITS™) during all practices and games. All players received pre- and postseason MRI, including diffusion tensor imaging (DTI). Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) was also conducted. Total impacts and risk-weighted cumulative exposure (RWE), including linear (RWELinear), rotational (RWERotational), and combined components (RWECP), were computed from the sensor data. Fractional, linear, planar, and spherical anisotropies (FA, CL, CP, and CS, respectively), as well as mean diffusivity (MD), were used to determine total number of abnormal white matter voxels defined as 2 standard deviations above or below the group mean. Delta (post-preseason) ImPACT scores for each individual were computed and compared to the DTI measures using Spearman's rank correlation coefficient. None of the players analyzed experienced clinical concussion (N=24). Regression analysis revealed a statistically significant linear relationship between RWECP and FA. Secondary analyses demonstrated additional statistically significant linear associations between RWE (RWECP and RWELinear) and all DTI measures. There was also a strong correlation between DTI measures and change in Verbal Memory subscore of the ImPACT. We demonstrate that a single season of football can produce brain MRI changes in the absence of clinical concussion. Similar brain MRI changes have been previously associated with mild traumatic brain injury.

  17. Deployable Emergency Shutoff Device Blocks High-Velocity Fluid Flows

    NASA Technical Reports Server (NTRS)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center has developed a device and method for blocking the flow of fluid from an open pipe. Motivated by the sea-bed oil-drilling catastrophe in the Gulf of Mexico in 2010, NASA innovators designed the device to plug, control, and meter the flow of gases and liquids. Anchored with friction fittings, spikes, or explosively activated fasteners, the device is well-suited for harsh environments and high fluid velocities and pressures. With the addition of instrumentation, it can also be used as a variable area flow metering valve that can be set based upon flow conditions. With robotic additions, this patent-pending innovation can be configured to crawl into a pipe then anchor and activate itself to block or control fluid flow.

  18. Laser velocimetry in highly three-dimensional and vortical flows

    NASA Technical Reports Server (NTRS)

    Novak, C. J.; Huie, C. R.; Cornelius, K. C.

    1986-01-01

    The need for experimentally determined 3-D velocity information is crucial to the understanding of highly 3-dimensional and vortical flow fields. In addition to gaining an understanding of the physics of flow fields, a correlation of velocity data is needed for advanced computational modelling. A double pass method for acquiring 3-D flow field information using a 2-D laser velocimeter (LV) is described. The design and implementation of a 3-D LV with expanded capabilities to acquire real-time 3-D flow field information are also described. Finally, the use of such an instrument in a wind tunnel study of a generic fighter configuration is described. The results of the wind tunnel study highlight the complexities of 3-D flow fields, particularly when the vortex behavior is examined over a range of angles of attack.

  19. Investigation Flow Uniformity in a Supersonic Duct with High Enthalpy Flows

    NASA Technical Reports Server (NTRS)

    Balboni, John; Atler, Doug; Gokcen, Tahir; Hartman, G. Joseph (Technical Monitor)

    1995-01-01

    Flow uniformity in a high enthalpy facility is investigated. The scramjet research facility is composed of a rectangular combustor duct connected to a 100 MW electric arc air heater. The Mach 3.3 flow is accelerated through a two-dimensional contoured nozzle. Instream measurements were made with water-cooled Pitot probes and stagnation point heat flux gages at stream enthalpy levels ranging from 4 to 7 Mj/kg. Flow surveys were made on the flow centerline and off centerline in order to measure the three dimensional uniformity of the flow in the rectangular duct. Measurements indicated that although the flow in the aspect ratio 6:1 duct was relatively uniform on the centerline, three dimensional viscous effects were apparent near the corners. Flow through the nozzle and constant area duct was modeled computationally using a two dimensional, Navier-Stokes, reacting gas code. The computations predict that the flow in the test section is in vibrational equilibrium. The computed and measured Pitot pressure and heat flux profiles are in reasonable agreement with the experimental data.

  20. Troxerutin suppresses lipid abnormalities in the heart of high-fat-high-fructose diet-fed mice.

    PubMed

    Geetha, Rajagopalan; Yogalakshmi, Baskaran; Sreeja, S; Bhavani, K; Anuradha, Carani Venkatraman

    2014-02-01

    The reversal effect of troxerutin (TX) on obesity, insulin resistance, lipid accumulation, oxidative damage, and hypertension induced in the high-fat-high-fructose diet (HFFD)-fed mice model of metabolic syndrome was investigated. Adult male Mus musculus mice of body weight 25-30 g were fed either control diet or HFFD. Each group was divided into two and treated or untreated with TX (150 mg/kg bw, p.o.) from the 16th day. Assays were done in plasma and heart after 30 and 60 days of the experimental period. Significant increase in the levels of glucose and insulin, blood pressure (BP), and oxidative stress were observed after 30 days of HFFD feeding as compared to control. Animals fed HFFD for 60 days developed more severe changes in the above parameters compared to those fed for 30 days. Hearts of HFFD-fed mice registered downregulation of peroxisome proliferator-activated receptor-α and peroxisome proliferator-activated receptor gamma coactivator-1α, carnitine palmitoyl transferse-1b and AMP-activated protein kinase; and upregulation of cluster of differentiation 36, fatty acid-binding protein-1, and sterol regulatory element-binding protein-1c after 60 days. TX administration restricted obesity (as seen by Lee's index); improved whole body insulin sensitivity; reduced BP, lipid accumulation, and oxidative damage; upregulated fatty acid (FA) oxidation; and downregulated FA transport and lipogenesis. Histology of heart revealed that TX diminishes inflammatory cell infiltration and fatty degeneration in HFFD-fed mice. The antioxidant property of TX and its ability to influence lipid regulatory genes could be the underlying mechanisms for its beneficial effects. PMID:24173620

  1. Troxerutin suppresses lipid abnormalities in the heart of high-fat-high-fructose diet-fed mice.

    PubMed

    Geetha, Rajagopalan; Yogalakshmi, Baskaran; Sreeja, S; Bhavani, K; Anuradha, Carani Venkatraman

    2014-02-01

    The reversal effect of troxerutin (TX) on obesity, insulin resistance, lipid accumulation, oxidative damage, and hypertension induced in the high-fat-high-fructose diet (HFFD)-fed mice model of metabolic syndrome was investigated. Adult male Mus musculus mice of body weight 25-30 g were fed either control diet or HFFD. Each group was divided into two and treated or untreated with TX (150 mg/kg bw, p.o.) from the 16th day. Assays were done in plasma and heart after 30 and 60 days of the experimental period. Significant increase in the levels of glucose and insulin, blood pressure (BP), and oxidative stress were observed after 30 days of HFFD feeding as compared to control. Animals fed HFFD for 60 days developed more severe changes in the above parameters compared to those fed for 30 days. Hearts of HFFD-fed mice registered downregulation of peroxisome proliferator-activated receptor-α and peroxisome proliferator-activated receptor gamma coactivator-1α, carnitine palmitoyl transferse-1b and AMP-activated protein kinase; and upregulation of cluster of differentiation 36, fatty acid-binding protein-1, and sterol regulatory element-binding protein-1c after 60 days. TX administration restricted obesity (as seen by Lee's index); improved whole body insulin sensitivity; reduced BP, lipid accumulation, and oxidative damage; upregulated fatty acid (FA) oxidation; and downregulated FA transport and lipogenesis. Histology of heart revealed that TX diminishes inflammatory cell infiltration and fatty degeneration in HFFD-fed mice. The antioxidant property of TX and its ability to influence lipid regulatory genes could be the underlying mechanisms for its beneficial effects.

  2. Numerical Simulation of High-Speed Turbulent Reacting Flows

    NASA Technical Reports Server (NTRS)

    Givi, P.; Taulbee, D. B.; Madnia, C. K.; Jaberi, F. A.; Colucci, P. J.; Gicquel, L. Y. M.; Adumitroaie, V.; James, S.

    1999-01-01

    The objectives of this research are: (1) to develop and implement a new methodology for large eddy simulation of (LES) of high-speed reacting turbulent flows. (2) To develop algebraic turbulence closures for statistical description of chemically reacting turbulent flows. We have just completed the third year of Phase III of this research. This is the Final Report of our activities on this research sponsored by the NASA LaRC.

  3. Modeling high flow speeds in the inner corona

    SciTech Connect

    Esser, Ruth; Habbal, Shadia Rifai

    1996-07-20

    Following recent observations which indicate the possibility of extremely high flow speeds in the inner corona, 700-800 km s{sup -1} below 10 R{sub S}, and the possibility of very high proton temperatures, T{sub p}{<=}8.5x10{sup 6} K, we present a new approach to solar wind modeling. In this approach we show that if the high proton temperatures in the inner corona are genuine, then flow speeds of 700 to 800 km s{sup -1} can readily be achieved at 10 R{sub S} or even closer to the coronal base.

  4. Unsteady flow in the nasal cavity with high flow therapy measured by stereoscopic PIV

    NASA Astrophysics Data System (ADS)

    Spence, C. J. T.; Buchmann, N. A.; Jermy, M. C.

    2012-03-01

    Nasal high flow (NHF) cannulae are used to deliver heated and humidified air to patients at steady flows ranging from 5 to 50 l/min. In this study, the flow velocities in the nasal cavity across the complete respiratory cycle during natural breathing and with NHF has been mapped in vitro using time-resolved stereoscopic particle image velocimetry (SPIV). An anatomically accurate silicone resin model of a complete human nasal cavity was constructed using CT scan data and rapid prototyping. Physiological breathing waveforms were reproduced in vitro using Reynolds and Womersley number matching and a piston pump driven by a ball screw and stepper motor. The flow pattern in the nasal cavity with NHF was found to differ significantly from natural breathing. Velocities of 2.4 and 3.3 ms-1 occurred in the nasal valve during natural breathing at peak expiration and inspiration, respectively; however, on expiration, the maximum velocity of 3.8 ms-1 occurred in the nasopharynx. At a cannula flow rate of 30 l/min, maximal velocities of 13.6 and 16.5 ms-1 at peak expiration and inspiration, respectively, were both located in the cannula jet within the nasal valve. Results are presented that suggest the quasi-steady flow assumption is invalid in the nasal cavity during natural breathing; however, it was valid with NHF. Cannula flow has been found to continuously flush the nasopharyngeal dead space, which may enhance carbon dioxide removal and increase oxygen fraction.

  5. The Steady Flow Resistance of Perforated Sheet Materials in High Speed Grazing Flows

    NASA Technical Reports Server (NTRS)

    Syed, Asif A.; Yu, Jia; Kwan, H. W.; Chien, E.; Jones, Michael G. (Technical Monitor)

    2002-01-01

    A study was conducted to determine the effects of high speed grazing air flow on the acoustic resistance of perforated sheet materials used in the construction of acoustically absorptive liners placed in commercial aircraft engine nacelles. Since DC flow resistance of porous sheet materials is known to be a major component of the acoustic resistance of sound suppression liners, the DC flow resistance of a set of perforated face-sheets and linear 'wiremesh' face-sheets was measured in a flow duct apparatus (up to Mach 0.8). Samples were fabricated to cover typical variations in perforated face-sheet parameters, such as hole diameter, porosity and sheet thickness, as well as those due to different manufacturing processes. The DC flow resistance data from perforated sheets were found to correlate strongly with the grazing flow Mach number and the face-sheet porosity. The data also show correlation against the boundary layer displacement thickness to hole-diameter ratio. The increase in resistance with grazing flow for punched aluminum sheets is in good agreement with published results up to Mach 0.4, but is significantly larger than expected above Mach 0.4. Finally, the tests demonstrated that there is a significant increase in the resistance of linear 'wiremesh' type face-sheet materials.

  6. Sulphur-impregnated flow cathode to enable high-energy-density lithium flow batteries

    NASA Astrophysics Data System (ADS)

    Chen, Hongning; Zou, Qingli; Liang, Zhuojian; Liu, Hao; Li, Quan; Lu, Yi-Chun

    2015-01-01

    Redox flow batteries are promising technologies for large-scale electricity storage, but have been suffering from low energy density and low volumetric capacity. Here we report a flow cathode that exploits highly concentrated sulphur-impregnated carbon composite, to achieve a catholyte volumetric capacity 294 Ah l-1 with long cycle life (>100 cycles), high columbic efficiency (>90%, 100 cycles) and high energy efficiency (>80%, 100 cycles). The demonstrated catholyte volumetric capacity is five times higher than the all-vanadium flow batteries (60 Ah l-1) and 3-6 times higher than the demonstrated lithium-polysulphide approaches (50-117 Ah l-1). Pseudo-in situ impedance and microscopy characterizations reveal superior electrochemical and morphological reversibility of the sulphur redox reactions. Our approach of exploiting sulphur-impregnated carbon composite in the flow cathode creates effective interfaces between the insulating sulphur and conductive carbon-percolating network and offers a promising direction to develop high-energy-density flow batteries.

  7. Enhancement of USM3D Unstructured Flow Solver for High-Speed High-Temperature Shear Flows

    NASA Technical Reports Server (NTRS)

    Pandya, Mohagna J.; Abdol-Hamid, Khaled S.; Frink, Neal T.

    2009-01-01

    Large temperature and pressure fluctuations have a profound effect on turbulence development in transonic and supersonic jets. For high-speed, high-temperature jet flows, standard turbulence models lack the ability to predict the observed mixing rate of a shear layer. Several proposals to address this deficiency have been advanced in the literature to modify the turbulence transport equations in a variety of ways. In the present study, some of the most proven and simple modifications to two-equation turbulence models have been selected and implemented in NASA's USM3D tetrahedral Navier-Stokes flow solver. The modifications include the addition of compressibility correction and pressure dilatation terms in the turbulence transport equations for high-speed flows, and the addition of a simple modification to the Boussinesq's closure model coefficient for high-temperature jets. The efficacy of the extended models is demonstrated by comparison with experimental data for two supersonic axisymmetric jet test cases at design pressure ratio.

  8. Abnormally high ammonium of natural origin in a coastal aquifer-aquitard system in the Pearl River Delta, China.

    PubMed

    Jiao, Jiu Jimmy; Wang, Ya; Cherry, John A; Wang, Xusheng; Zhi, Bingfa; Du, Haiyan; Wen, Dongguang

    2010-10-01

    High-nitrogen loadings of rivers and aquifers systems are a major concern because of potential effects on human health and water quality impacts such as eutrophication of lakes and coastal zones. This nitrogen enrichment is commonly attributed to anthropogenic sources such as sewage and agricultural and industrial wastes. The aims of this study were to delineate spatial distribution of groundwater ammonium in the coastal aquifer system in Pearl River Delta (PRD), China and to identify the origin of the abnormally high ammonium. A total of 40 boreholes were drilled to collect core samples of the aquitard and groundwater samples in the basal aquifer. The core samples were used for extraction of pore water for centrifugation and bulk chemical analyses in laboratory. Unlike previous studies which focused mainly on the aquifer, this study treated the aquifer-aquitard system as a hydrogeochemical continuum. The results show that the aquifer-aquitard system contains an exceptionally large total ammonium mass. Ammonium occurred at concentrations up to 390 mg/L in the basal sand Pleistocene aquifer 20-50 m deep, the largest concentration reported for groundwater globally. This ammonium was natural, areally extensive (1600 km(2)) and originated in the overlying Holocene-Pleistocene aquitard and entered the aquifer by groundwater transport and diffusion. Total ammonium in the aquifer (190 × 10(6) kg) was exceeded by total ammonium in the aquitard (8600 × 10(6) kg) by a factor of 45. Much organic nitrogen remained in the aquitard available for conversion to ammonium. This natural ammonium in the aquifer was slowly transported into the PRD river channels and the estuary of the South China Sea. The rate of this contribution will likely be greatly increased by sand dredging in the river channels and estuary. Although the ammonium in PRD groundwater occurred in the largest concentrations and mass reported globally, the literature shows no reports of other delta aquitards having

  9. Channel Geometry and Flood Flows: Quantifying over-bank flow dynamics during high-flow events in North Carolina's floodplains

    NASA Astrophysics Data System (ADS)

    Lovette, J. P.; Duncan, J. M.; Vimal, S.; Band, L. E.

    2015-12-01

    Natural riparian areas play numerous roles in the maintenance and improvement of stream water quality. Both restoration of riparian areas and improvement of hydrologic connectivity to the stream are often key goals of river restoration projects. These management actions are designed to improve nutrient removal by slowing and treating overland flow delivered from uplands and by storing, treating, and slowly releasing streamwater from overbank inundation during flood events. A major question is how effective this storage of overbank flow is at treating streamwater based on the cumulative time stream discharge at a downstream location has spent in shallower, slower overbank flow. The North Carolina Floodplain Mapping Program maintains a detailed statewide Flood Risk Information System (FRIS) using HEC-RAS modeling, lidar, and detailed surveyed river cross-sections. FRIS provides extensive information regarding channel geometry on approximately 39,000 stream reaches (a slightly coarser spatial resolution than the NHD+v2 dataset) with tens of cross-sections for each reach. We use this FRIS data to calculate volume and discharge from floodplain riparian areas separately from in-channel flow during overbank events. Preliminary results suggest that a small percentage of total annual discharge interacts with the full floodplain extent along a stream reach due to the infrequency of overbank flow events. However, with the significantly different physical characteristics of the riparian area when compared to the channel itself, this overbank flow can provide unique services to water quality. Our project aims to use this information in conjunction with data from the USGS SPARROW program to target non-point source hotspots of Nitrogen and Phosphorus addition and removal. By better understanding the flow dynamics within riparian areas during high flow events, riparian restoration projects can be carried out with improved efficacy.

  10. Multiple states in highly turbulent Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    Huisman, Sander G.; van der Veen, Roeland C. A.; Sun, Chao; Lohse, Detlef

    2014-05-01

    The ubiquity of turbulent flows in nature and technology makes it of utmost importance to fundamentally understand turbulence. Kolmogorov’s 1941 paradigm suggests that for strongly turbulent flows with many degrees of freedom and large fluctuations, there would only be one turbulent state as the large fluctuations would explore the entire higher dimensional phase space. Here we report the first conclusive evidence of multiple turbulent states for large Reynolds number, Re(106) (Taylor number Ta(1012)) Taylor-Couette flow in the regime of ultimate turbulence, by probing the phase space spanned by the rotation rates of the inner and outer cylinder. The manifestation of multiple turbulent states is exemplified by providing combined global torque- and local-velocity measurements. This result verifies the notion that bifurcations can occur in high-dimensional flows (that is, very large Re) and questions Kolmogorov’s paradigm.

  11. Multiple states in highly turbulent Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    Huisman, Sander; van der Veen, Roeland; Sun, Chao; Lohse, Detlef

    2014-11-01

    The ubiquity of turbulent flows in nature and technology makes it of utmost importance to fundamentally understand turbulence. Kolmogorov's 1941 paradigm suggests that for strongly turbulent flows with many degrees of freedom and its large fluctuations, there would only be one turbulent state as the large fluctuations would explore the entire higher-dimensional phase space. Here we report the first conclusive evidence of multiple turbulent states for large Reynolds number Re = O (106) (Taylor number Ta = O (1012) Taylor-Couette flow in the regime of ultimate turbulence, by probing the phase space spanned by the rotation rates of the inner and outer cylinder. The manifestation of multiple turbulent states is exemplified by providing combined global torque and local velocity measurements. This result verifies the notion that bifurcations can occur in high-dimensional flows (i.e. very large Re) and questions Kolmogorov's paradigm.

  12. High-bandwidth continuous-flow arc furnace

    DOEpatents

    Hardt, David E.; Lee, Steven G.

    1996-01-01

    A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics.

  13. High-bandwidth continuous-flow arc furnace

    DOEpatents

    Hardt, D.E.; Lee, S.G.

    1996-08-06

    A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics. 4 figs.

  14. Vortex shedding flowmeters for liquids at high flow velocities

    NASA Technical Reports Server (NTRS)

    Siegwarth, J. D.

    1985-01-01

    A number of vortex shedding flowmeter designs for flow measurements in liquid oxygen ducts on the space shuttle main engines have been tested in a high head water flow test facility. The results have shown that a vortex shedding element or vane spanning the duct can give a linear response to an average flow velocity of 46 m/s (150 ft/s) in a 1 1/2 inch nominal (41 mm actual) diameter duct while a vane partially spanning the duct can give a linear response to velocities exceeding 55 m/s (180 ft/s). The maximum pressure drops across the flow sensing elements extrapolate to less than 0.7 MPa (100 psi) at 56 m/s (184 ft/s) for liquid oxygen. The test results indicate that the vanes probably cannot be scaled up with pipe size, at least not linearly.

  15. Skin friction measurements in high temperature high speed flows

    NASA Technical Reports Server (NTRS)

    Schetz, J. A.; Diller, Thomas E.; Wicks, A. L.

    1992-01-01

    An experimental investigation was conducted to measure skin friction along the chamber walls of supersonic combustors. A direct force measurement device was used to simultaneously measure an axial and transverse component of the small tangential shear force passing over a non-intrusive floating element. The floating head is mounted to a stiff cantilever beam arrangement with deflection due to the flow on the order of 0.00254 mm (0.0001 in.). This allowed the instrument to be a non-nulling type. A second gauge was designed with active cooling of the floating sensor head to eliminate non-uniform temperature effects between the sensor head and the surrounding wall. Samples of measurements made in combustor test facilities at NASA Langley Research Center and at the General Applied Science Laboratory (GASL) are presented. Skin friction coefficients between 0.001 - 0.005 were measured dependent on the facility and measurement location. Analysis of the measurement uncertainties indicate an accuracy to within +/- 10-15 percent of the streamwise component.

  16. Rarefied flow diagnostics using pulsed high-current electron beams

    NASA Technical Reports Server (NTRS)

    Wojcik, Radoslaw M.; Schilling, John H.; Erwin, Daniel A.

    1990-01-01

    The use of high-current short-pulse electron beams in low-density gas flow diagnostics is introduced. Efficient beam propagation is demonstrated for pressure up to 300 microns. The beams, generated by low-pressure pseudospark discharges in helium, provide extremely high fluorescence levels, allowing time-resolved visualization in high-background environments. The fluorescence signal frequency is species-dependent, allowing instantaneous visualization of mixing flowfields.

  17. A high-performance flow-field structured iron-chromium redox flow battery

    NASA Astrophysics Data System (ADS)

    Zeng, Y. K.; Zhou, X. L.; An, L.; Wei, L.; Zhao, T. S.

    2016-08-01

    Unlike conventional iron-chromium redox flow batteries (ICRFBs) with a flow-through cell structure, in this work a high-performance ICRFB featuring a flow-field cell structure is developed. It is found that the present flow-field structured ICRFB reaches an energy efficiency of 76.3% with a current density of 120 mA cm-2 at 25 °C. The energy efficiency can be as high as 79.6% with an elevated current density of 200 mA cm-2 at 65 °C, a record performance of the ICRFB in the existing literature. In addition, it is demonstrated that the energy efficiency of the battery is stable during the cycle test, and that the capacity decay rate of the battery is 0.6% per cycle. More excitingly, the high performance of the flow-field structured battery significantly lowers the capital cost at 137.6 kWh-1, which is 28.2% lower than that of the conventional ICRFB for 8-h energy storage.

  18. A high-performance flow-field structured iron-chromium redox flow battery

    NASA Astrophysics Data System (ADS)

    Zeng, Y. K.; Zhou, X. L.; An, L.; Wei, L.; Zhao, T. S.

    2016-08-01

    Unlike conventional iron-chromium redox flow batteries (ICRFBs) with a flow-through cell structure, in this work a high-performance ICRFB featuring a flow-field cell structure is developed. It is found that the present flow-field structured ICRFB reaches an energy efficiency of 76.3% with a current density of 120 mA cm-2 at 25 °C. The energy efficiency can be as high as 79.6% with an elevated current density of 200 mA cm-2 at 65 °C, a record performance of the ICRFB in the existing literature. In addition, it is demonstrated that the energy efficiency of the battery is stable during the cycle test, and that the capacity decay rate of the battery is 0.6% per cycle. More excitingly, the high performance of the flow-field structured battery significantly lowers the capital cost at 137.6 kWh-1, which is 28.2% lower than that of the conventional ICRFB for 8-h energy storage.

  19. High frequency flow-structural interaction in dense subsonic fluids

    NASA Technical Reports Server (NTRS)

    Liu, Baw-Lin; Ofarrell, J. M.

    1995-01-01

    Prediction of the detailed dynamic behavior in rocket propellant feed systems and engines and other such high-energy fluid systems requires precise analysis to assure structural performance. Designs sometimes require placement of bluff bodies in a flow passage. Additionally, there are flexibilities in ducts, liners, and piping systems. A design handbook and interactive data base have been developed for assessing flow/structural interactions to be used as a tool in design and development, to evaluate applicable geometries before problems develop, or to eliminate or minimize problems with existing hardware. This is a compilation of analytical/empirical data and techniques to evaluate detailed dynamic characteristics of both the fluid and structures. These techniques have direct applicability to rocket engine internal flow passages, hot gas drive systems, and vehicle propellant feed systems. Organization of the handbook is by basic geometries for estimating Strouhal numbers, added mass effects, mode shapes for various end constraints, critical onset flow conditions, and possible structural response amplitudes. Emphasis is on dense fluids and high structural loading potential for fatigue at low subsonic flow speeds where high-frequency excitations are possible. Avoidance and corrective measure illustrations are presented together with analytical curve fits for predictions compiled from a comprehensive data base.

  20. Associations between sexually transmitted infections, high-risk human papillomavirus infection, and abnormal cervical Pap smear results in OB/GYN outpatients

    PubMed Central

    Kim, Tae Jin

    2016-01-01

    Objective This study aimed to examine the meaning and usefulness of sexually transmitted infection (STI) test when caring for patients who have abnormal cervical cytology and/or positive high-risk human papillomavirus (HPV) DNA test results. Methods Among patients who underwent liquid-based cervical cytology and HPV DNA tests at the Obstetrics and Gynecology outpatient clinic, 800 patients who showed abnormal cervical cytology were compared with 200 patients in the control group. Both groups were simultaneously tested via multiplex real-time polymerase chain reaction for seven types of STI-causative microorganisms. Results The positive rate of high-risk HPV infection in total STIs positive group was 1.47 times higher than that of total STIs negative group. The probability of a cytological diagnosis of a grade equal to or higher than atypical squamous cells-cannot exclude high grade squamous intraepithelial lesion (ASC-H) was significantly higher in patients testing positive for total STIs (1.46 times), Chlamydia trachomatis (3.21 times), or Mycoplasma genitalicum (3.58 times) than in those testing negative. The total STIs positive rate was significantly higher for those having a cytological diagnosis of a grade equal to or higher than atypical squamous cells of undetermined significance (ASC-US) when high-risk HPV test result was negative. Conclusion Correlations were present not only between STIs and high-risk HPV infection but also between abnormal cervical cytology and STIs. Therefore, additional evaluation of STIs will be helpful to appropriately diagnose and treat patients with abnormal cervical cytology, positive results on high-risk HPV DNA test, or a cytological diagnosis of ASC-US despite negative high-risk HPV DNA test result. PMID:27329197

  1. High energy density Z-pinch plasmas using flow stabilization

    SciTech Connect

    Shumlak, U. Golingo, R. P. Nelson, B. A. Bowers, C. A. Doty, S. A. Forbes, E. G. Hughes, M. C. Kim, B. Knecht, S. D. Lambert, K. K. Lowrie, W. Ross, M. P. Weed, J. R.

    2014-12-15

    The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes – Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and

  2. Intensity fluctuations of ultrasonic scattering in a highly turbulent flow.

    PubMed

    Shen, C; Lemmin, U

    2000-05-01

    Aspects of ultrasound intensity fluctuations backscattered from additive microstructures in a turbulent flow have been investigated theoretically and experimentally for the conditions of a small insonified volume, a high sound frequency and strong turbulence. These conditions are typically found in high resolution Doppler sonar applications. An easily applicable expression for the auto-correlation of scattering intensity fluctuations is obtained by introducing open-channel turbulence theory, a semi-empirical scalar spectrum (including a Batchelor spectrum) and a Gaussian window function. Experiments carried out in a laboratory-clear water, open-channel flow for different turbulence levels verify the underlying assumptions. A good agreement is found with the predictions made with the above-derived expression. The feasibility of extracting flow information from the backscattered intensity fluctuations is discussed.

  3. Measurements of granular flow dynamics with high speed digital images

    SciTech Connect

    Lee, J.

    1994-12-31

    The flow of granular materials is common to many industrial processes. This dissertation suggests and validates image processing algorithms applied to high speed digital images to measure the dynamics (velocity, temperature and volume fraction) of dry granular solids flowing down an inclined chute under the action of gravity. Glass and acrylic particles have been used as granular solids in the experiment. One technique utilizes block matching for spatially averaged velocity measurements of the glass particles. This technique is compared with the velocity measurement using an optic probe which is a conventional granular flow velocity measurement device. The other technique for measuring the velocities of individual acrylic particles is developed with correspondence using a Hopfield network. This technique first locates the positions of particles with pattern recognition techniques, followed by a clustering technique, which produces point patterns. Also, several techniques are compared for particle recognition: synthetic discriminant function (SDF), minimum average correlation energy (MACE) filter, modified minimum average correlation energy (MMACE) filter and variance normalized correlation. The author proposes an MMACE filter which improves generalization of the MACE filter by adjusting the amount of averaged spectrum of training images in the spectrum whitening stages of the MACE filter. Variance normalized correlation is applied to measure the velocity and temperature of flowing glass particles down the inclined chute. The measurements are taken for the steady and wavy flow and qualitatively compared with a theoretical model of granular flow.

  4. Characterization of non equilibrium effects on high quality critical flows

    SciTech Connect

    Camelo, E.; Lemonnier, H.; Ochterbeck, J.

    1995-09-01

    The appropriate design of various pieces of safety equipment such as relief systems, relies on the accurate description of critical flow phenomena. Most of the systems of industrial interest are willing to be described by one-dimensional area-averaged models and a large fraction of them involves multi-component high gas quality flows. Within these circumstances, the flow is very likely to be of an annular dispersed nature and its description by two-fluid models requires various closure relations. Among the most sensitive closures, there is the interfacial area and the liquid entrained fraction. The critical flowrate depends tremendously on the accurate description of the non equilibrium which results from the correctness of the closure equations. In this study, two-component flows are emphasized and non equilibrium results mainly form the differences in the phase velocities. It is therefore of the utmost importance to have reliable data to characterize non equilibrium phenomena and to assess the validity of the closure models. A comprehensive description of air-water nozzle flows, with emphasis on the effect of the nozzle geometry, has been undertaken and some of the results are presented here which helps understanding the overall flow dynamics. Besides the critical flowrate, the presented material includes pressure profiles, droplet size and velocity, liquid film flowrate and liquid film thickness.

  5. Do sleep abnormalities and misaligned sleep/circadian rhythm patterns represent early clinical characteristics for developing psychosis in high risk populations?

    PubMed

    Zanini, Marcio; Castro, Juliana; Coelho, Fernando Morgadinho; Bittencourt, Lia; Bressan, Rodrigo A; Tufik, Sergio; Brietzke, Elisa

    2013-12-01

    Sleep architecture changes, such as slow-wave sleep (SWS) percentage variations and reductions in latency and density of rapid eye movement (REM), are found in most patients with schizophrenia and are considered to be an important part of the pathophysiology of the disorder. In addition to these sleep parameters changes, disruptions in sleep homeostasis and the sleep/circadian rhythm also occur in these patients. Sleep/circadian rhythm abnormalities negatively affect neocortical plasticity and cognition and often precede the diagnosis of the illness. Thus, it has been suggested that the sleep/circadian rhythm might be involved in the pathophysiology of psychosis. Recent advances in the identification of individuals at a high risk for developing schizophrenia allow us to investigate several neurobiological processes involved in the development of psychosis. In this article, we review the current evidence of the effects of sleep parameter abnormalities, disruptions in sleep homeostasis and misalignments of sleep circadian rhythm on the early stages of schizophrenia. In addition, we discuss the preliminary evidence of sleep and circadian rhythm abnormalities during the prodromal stages of psychosis and propose that these abnormalities can be explored as potential predictors, as an adjunct to clinical diagnosis, of developing a psychotic disorder in at risk populations.

  6. Results of high-dose therapy for 1000 patients with multiple myeloma: durable complete remissions and superior survival in the absence of chromosome 13 abnormalities.

    PubMed

    Desikan, R; Barlogie, B; Sawyer, J; Ayers, D; Tricot, G; Badros, A; Zangari, M; Munshi, N C; Anaissie, E; Spoon, D; Siegel, D; Jagannath, S; Vesole, D; Epstein, J; Shaughnessy, J; Fassas, A; Lim, S; Roberson, P; Crowley, J

    2000-06-15

    High-dose therapy (HDT) has increased complete remission (CR) rates and survival in multiple myeloma (MM). We now report on continuous CR (CCR) and associated prognostic factors in 1000 consecutive patients receiving melphalan-based tandem HDT. Five-year CCR was 52% among 112 CR patients without chromosome 13 (triangle up13) abnormalities and with beta-2-microglobulin abnormalities, 35% enjoyed 5-year CCR but none of 54 with triangle up13 abnormalities. triangle up13 abnormalities, present in overall 16%, reduced 5-year event-free survival from 20% to 0% and overall survival from 44% to 16% (both P <.0001). CR and a second HDT cycle applied within 6 months both extended event-free and overall survival significantly, justifying further pursuit of HDT, especially toward curing non-triangle up13 MM. (Blood. 2000;95:4008-4010)

  7. Flow-ejecta Crater in Icaria Planum - High Resolution Image

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Mars Global Surveyor Orbiter Camera (MOC) acquired this high resolution image of a flow ejecta crater on November 19, 1997, at 8:26 PM PST, about 18 minutes after the start the 45th orbit of Mars. The area shown is roughly 6.5 by 40.2 kilometers (4 by 25 miles), and is located near 40 degrees South latitude, 120 degrees West longitude. Features as small as 15-18 m (50-60 feet) across are visible in the picture.

    Flow ejecta craters are so named because the material blasted out of the crater during the impact process appears to have flowed across the surface of Mars. First seen in Mariner 9 images in 1973, and described in detail using Viking Orbiter images acquired in 1976-78, flow-ejecta craters are considered by many scientists to be evidence that liquid water could be found in the near-subsurface at the time the craters formed. This image, a factor of two better than any previous view of such features (and a factor of 33 better than the best Viking frame of the specific crater, 056A61), shows two smaller, pre-existing craters and the interaction of the flowing ejecta with these craters. The uppermost small crater has been over-topped and partly buried by the flow, while the flow has been diverted around the lower crater. Ridges formed where the flow 'stacked up' behind obstacles, or came to rest.

    Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  8. Numerical Simulation of High-Speed Turbulent Reacting Flows

    NASA Technical Reports Server (NTRS)

    Jaberi, F. A.; Colucci, P. J.; James, S.; Givi, P.

    1996-01-01

    The purpose of this research is to continue our efforts in advancing the state of knowledge in large eddy simulation (LES) methods for computational analysis of high-speed reacting turbulent flows. We have just completed the first year of Phase 3 of this research.

  9. Flow Analysis By High Speed Photography And Pictures

    NASA Astrophysics Data System (ADS)

    Werle, H.

    1985-02-01

    At the ONERA hydrodynamic visualization laboratory, high-speed photography and cinematography are used for analysing flow-phenomena around fixed or mobile models in the test section of three vertical water tunnels, operating by gravity draining. These studies in water are based on the hydraulic analogy of aerodynamic incompressible flows. Flow visualization is archieved by liquid tracers (dye emissions) or gaseous tracers (fine air bubbles in suspension in water). In many cases, the pictures at normal speed or long exposure time are insufficient, for they do not permit to distinguish all the details of the phenomena, due to an averaging or motion effect. Furthermore they must be completed with high speed pictures. This is illustrated by a few visua-lization examples recently obtained on following themes - two dimensional flow around a fixed cylinder, first at the start of the flow (symmetrical vortex), then in steady regime (periodic vortex street) ; - laminar-turbulent transition in a boundary layer along a cylindrical body at zero angle of attack ; - flow separation around a sphere and wake in steady regime at small and high Reynolds numbers; - flow separation around a profile, first with fixed incidence, then with harmonic oscillations in pitch ; - core structure of a longitudinal vortex issued from a wing first organized, then disintegrated under the effect of a lengthwise pressure gradient (vortex breakdown) ; - mixing zone around a turbulent axisymmetric jet, characterized by the formation of large vortex struc-tures ; - hovering tests of an helicopter rotor, first at the start of the rotation, then in established regime, finally in cruise flight ; - case of a complete helicopter model in cruise-flight, with air-intake simulation, gas exhaust and tail rotor ; - flow around a complete delta-wing aircraft model at mean or high angle of attack, first in steady regime, then with harmonic oscillations in yaw or pitch. These results illustrate the contribution of

  10. High-resolution DEM Effects on Geophysical Flow Models

    NASA Astrophysics Data System (ADS)

    Williams, M. R.; Bursik, M. I.; Stefanescu, R. E. R.; Patra, A. K.

    2014-12-01

    Geophysical mass flow models are numerical models that approximate pyroclastic flow events and can be used to assess the volcanic hazards certain areas may face. One such model, TITAN2D, approximates granular-flow physics based on a depth-averaged analytical model using inputs of basal and internal friction, material volume at a coordinate point, and a GIS in the form of a digital elevation model (DEM). The volume of modeled material propagates over the DEM in a way that is governed by the slope and curvature of the DEM surface and the basal and internal friction angles. Results from TITAN2D are highly dependent upon the inputs to the model. Here we focus on a single input: the DEM, which can vary in resolution. High resolution DEMs are advantageous in that they contain more surface details than lower-resolution models, presumably allowing modeled flows to propagate in a way more true to the real surface. However, very high resolution DEMs can create undesirable artifacts in the slope and curvature that corrupt flow calculations. With high-resolution DEMs becoming more widely available and preferable for use, determining the point at which high resolution data is less advantageous compared to lower resolution data becomes important. We find that in cases of high resolution, integer-valued DEMs, very high-resolution is detrimental to good model outputs when moderate-to-low (<10-15°) slope angles are involved. At these slope angles, multiple adjacent DEM cell elevation values are equal due to the need for the DEM to approximate the low slope with a limited set of integer values for elevation. The first derivative of the elevation surface thus becomes zero. In these cases, flow propagation is inhibited by these spurious zero-slope conditions. Here we present evidence for this "terracing effect" from 1) a mathematically defined simulated elevation model, to demonstrate the terracing effects of integer valued data, and 2) a real-world DEM where terracing must be

  11. Numerical Simulations of High-Speed Flows Over Complex Geometries

    NASA Astrophysics Data System (ADS)

    Greene, Patrick Timothy

    The effects of surface roughness on the stability of hypersonic flow are of great importance to hypersonic vehicles. Surface roughness can greatly alter boundary-layer flow and cause transition to turbulence to occur much earlier compared to a smooth wall, which will result in a significant increase of wall heating and skin friction drag. The work presented in this dissertation was motivated by a desire to study the effects of isolated roughness elements on the stability of hypersonic boundary layers. A new code was developed which can perform high-order direct numerical simulations of high-speed flows over arbitrary geometries. A fifth-order hybrid weighted essentially non-oscillatory scheme was implemented to capture any steep gradients in the flow created by the geometries. The simulations are carried out on Cartesian grids with the geometries imposed by a third-order cut-cell method. A multi-zone refinement method is also implemented to provide extra resolution at locations with expected complex physics. The combination results in a globally fourth-order scheme. Results for two-dimensional and three-dimensional test cases show good agreement with previous results and will be presented. Results confirming the code's high order of convergence will also be shown. Two-dimensional simulations of flow over complex geometries will be presented to demonstrate the code's capabilities. Results for Mach 6 flow over a three-dimensional cylindrical roughness element will also be presented. The results will show that the code is a promising tool for the study of hypersonic roughness-induced transition.

  12. Flow lasers. [fluid mechanics of high power continuous output operations

    NASA Technical Reports Server (NTRS)

    Christiansen, W. H.; Russell, D. A.; Hertzberg, A.

    1975-01-01

    The present work reviews the fluid-mechanical aspects of high-power continuous-wave (CW) lasers. The flow characteristics of these devices appear as classical fluid-mechanical phenomena recast in a complicated interactive environment. The fundamentals of high-power lasers are reviewed, followed by a discussion of the N2-CO2 gas dynamic laser. Next, the HF/DF supersonic diffusion laser is described, and finally the CO electrical-discharge laser is discussed.

  13. Computation of high Reynolds number internal/external flows

    NASA Technical Reports Server (NTRS)

    Cline, M. C.; Wilmoth, R. G.

    1981-01-01

    A general, user oriented computer program, called VNAF2, developed to calculate high Reynolds number internal/external flows is described. The program solves the two dimensional, time dependent Navier-Stokes equations. Turbulence is modeled with either a mixing length, a one transport equation, or a two transport equation model. Interior grid points are computed using the explicit MacCormack scheme with special procedures to speed up the calculation in the fine grid. All boundary conditions are calculated using a reference plane characteristic scheme with the viscous terms treated as source terms. Several internal, external, and internal/external flow calculations are presented.

  14. High speed optical holography of retinal blood flow

    NASA Astrophysics Data System (ADS)

    Pellizzari, M.; Simonutti, M.; Degardin, J.; Sahel, J.-A.; Fink, M.; Paques, M.; Atlan, M.

    2016-08-01

    We performed non-invasive video imaging of retinal blood flow in a pigmented rat by holographic interferometry of near-infrared laser light backscattered by retinal tissue, beating against an off-axis reference beam sampled at a frame rate of 39 kHz with a high throughput camera. Local Doppler contrasts emerged from the envelopes of short-time Fourier transforms and the phase of autocorrelation functions of holograms rendered by Fresnel transformation. This approach permitted imaging of blood flow in large retinal vessels (30 microns diameter) over 400 by 400 pixels with a spatial resolution of 8 microns and a temporal resolution of 6.5 ms.

  15. Flux-flow resistivity of three high-temperature superconductors

    SciTech Connect

    Cha, Y.S.; Evans, D.J.; Hull, J.R.; Seol, S.Y.

    1996-10-01

    Results of experiments on flux-flow resistivity (the relationship of voltage to current) of three high-temperature superconductors are described. The superconductors are a melt-cast BSCCO 2212 rod, a single filament BSCCO powder-in-tube (PIT) tape, and a multifilament PIT tape. The flux-flow resistivity of these superconductors was measured at three temperatures: 77 K (saturated liquid nitrogen), 87 K (saturated liquid argon), and 67 K (subcooled liquid nitrogen). Implications of the present results for practical applications are discussed.

  16. Hypertension, abnormal cholesterol, and high body mass index among non-Hispanic Asian adults: United States, 2011-2012.

    PubMed

    Aoki, Yutaka; Yoon, Sung Sug; Chong, Yinong; Carroll, Margaret D

    2014-01-01

    Non-Hispanic Asian adults constituted 4.9% of the U.S. population in 2012, corresponding to 15.4 million people (2). This group primarily comprises persons of Chinese, Asian Indian, Korean, Filipino, Vietnamese, and Japanese descent. The prevalence of hypertension (defined as having blood pressure greater than or equal to 140/90 mm Hg or taking blood pressure-lowering medications) among non-Hispanic Asian adults aged 20 and over was 25.6%. As previously reported, this prevalence is similar to that of non-Hispanic white adults and Hispanic adults but lower than that of non-Hispanic black adults (3). Among non-Hispanic Asian adults, the prevalence of hypertension was higher among those who were older or had less education, similar to findings in U.S. adults overall (4,5). The prevalence of high total cholesterol (measured as cholesterol of at least 240 mg/dL) among non-Hispanic Asian adults was similar to that among adults of other race and Hispanic origin groups (6). Non-Hispanic Asian adults had a lower prevalence of low HDL cholesterol (measured as HDL less than 40 mg/dL) than Hispanic persons (6). Non-Hispanic Asian adult men were almost five times more likely than non-Hispanic Asian adult women to have low HDL cholesterol. While adult men in general are known to have a higher prevalence of low HDL cholesterol than adult women (7), the sex difference was larger than in other race and Hispanic origin groups (6). The prevalence of high BMI among non-Hispanic Asian adults (38.6%) was much lower than that previously reported for non-Hispanic white adults (66.7%), non-Hispanic black adults (76.7%), and Hispanic adults (78.8%) (8). BMI is widely used as a measure of body fat. However, at a given BMI level, body fat may vary by sex, age, and race and Hispanic origin. In particular, at a given BMI, Asian adults may have more body fat than white adults (9). Also, morbidity and mortality risk may be influenced by body composition and fat distribution in a manner that is

  17. SHARP simulation of discontinuities in highly convective steady flow

    NASA Technical Reports Server (NTRS)

    Leonard, B. P.

    1987-01-01

    For steady multidimesional convection, the Quadratic Upstream Interpolation for Convective Kinematics (QUICK) scheme has several attractive properties. However, for highly convective simulation of step profiles, QUICK produces unphysical overshoots and a few oscillations, and this may cause serious problems in nonlinear flows. Fortunately, it is possible to modify the convective flux by writing the normalized convected control-volume face value as a function of the normalized adjacent upstream node value, developing criteria for monotonic resolution without sacrificing formal accuracy. This results in a nonlinear functional relationship between the normalized variables, whereas standard methods are all linear in this sense. The resulting Simple High Accuracy Resolution Program (SHARP) can be applied to steady multidimensional flows containing thin shear or mixing layers, shock waves, and other frontal phenomena. This represents a significant advance in modeling highly convective flows of engineering and geophysical importance. SHARP is based on an explicit, conservative, control-volume flux formation, equally applicable to one, two, or three dimensional elliptic, parabolic, hyperbolic, or mixed-flow regimes. Results are given for the bench-mark purely convective first-order results and the nonmonotonic predictions of second- and third-order upwinding.

  18. High speed turbulent reacting flows: DNS and LES

    NASA Technical Reports Server (NTRS)

    Givi, Peyman

    1990-01-01

    Work on understanding the mechanisms of mixing and reaction in high speed turbulent reacting flows was continued. Efforts, in particular, were concentrated on taking advantage of modern computational methods to simulate high speed turbulent flows. In doing so, two methodologies were used: large eddy simulations (LES) and direct numerical simulations (DNS). In the work related with LES the objective is to study the behavior of the probability density functions (pdfs) of scalar properties within the subgrid in reacting turbulent flows. The data base obtained by DNS for a detailed study of the pdf characteristics within the subgrid was used. Simulations are performed for flows under various initializations to include the effects of compressibility on mixing and chemical reactions. In the work related with DNS, a two-dimensional temporally developing high speed mixing layer under the influence of a second-order non-equilibrium chemical reaction of the type A + B yields products + heat was considered. Simulations were performed with different magnitudes of the convective Mach numbers and with different chemical kinetic parameters for the purpose of examining the isolated effects of the compressibility and the heat released by the chemical reactions on the structure of the layer. A full compressible code was developed and utilized, so that the coupling between mixing and chemical reactions is captured in a realistic manner.

  19. Abnormally high body mass index and tobacco use are associated with poor sperm quality as revealed by reduced sperm binding to hyaluronan-coated slides.

    PubMed

    Wegner, Carole C; Clifford, Alicia L; Jilbert, Patricia M; Henry, Michael A; Gentry, William L

    2010-01-01

    Responses on a lifestyle questionnaire were correlated with results from traditional semen analysis and a newer functional sperm assay, namely, the ability of sperm to bind to a hyaluronan-coated slide. Increased percent normal morphology and motile sperm concentration were positively correlated with increased HA-binding score, whereas tobacco use (either current or previous history) and abnormally high body mass index were associated with lower binding scores.

  20. Experimental investigations of He II flows at high Reynolds number

    NASA Technical Reports Server (NTRS)

    Van Sciver, Steve W.

    1991-01-01

    Fluid dynamics studies of He II at high Reynolds number (Re(d) greater than 10 exp 6) reveal characteristics which are best interpreted in terms of classical scaling relationships. In particular, the smooth tube friction factor is seen to correlate with the Von Karman-Nikuradse formulation. Also, the performance of a centrifugal pump is unchanged whether being used with He I or He II. These effects are expected to result provided the He II possesses a viscous sublayer and that the drag is determined by laminar flow within this layer. On the other hand, heat transfer in He II is substantially different from that of He I because of the unique internal convection mechanism present in this quantum fluid. These experiments are performed in the University of Wisconsin liquid helium flow facility which has unique capabilities of He II temperature, pressure and flow.

  1. Human papillomavirus genotyping as a predictor of high-grade cervical dysplasia in women with mildly cytologic abnormalities: a two-year follow-up report.

    PubMed

    Huang, Lee-Wen; Lin, Yu-Hung; Pan, Hun-Shan; Seow, Kok-Min; Lin, Ching-Yu

    2012-08-01

    High-risk human papillomavirus (HR-HPV) DNA testing has emerged as another testing modality for women with mildly cytologic abnormalities. We conducted a two-year follow-up study of 108 women with mildly abnormal cervical cytology for detection of CIN 2/3. A cervical swab sample was obtained for HPV genotyping by a HPV blot and histologic follow-up results were correlated with HR-HPV types. Of the 108 cases, 93 (86.1%) were positive for HR-HPV DNA. HPV-16 was detected in 45.1% of patients. CIN grade 2 or 3 was confirmed in 25 (23.1%) of the 108 women during the two-year follow-up period. The two-year cumulative incidence rates of CIN 2/3 were 38.6% (17/44) among HPV-16- positive women, but only 5.6% among HR-HPV-positive women without HPV-16 or HPV-18. The sensitivity of a positive HPV-16 test for CIN 2/3 was 68.0%, the specificity was 67.5%. Our results demonstrated that the type-specific HPV-16 test increased sensitivity of detecting high-grade cervical dysplasia for women who have mildly cytologic abnormalities. The implication of the present findings is that HPV genotyping may identify women with the greatest risk of high-grade CIN.

  2. Water Flow in the High Plains Aquifer in Northwestern Oklahoma

    USGS Publications Warehouse

    Luckey, Richard R.; Osborn, Noel I.; Becker, Mark F.; Andrews, William J.

    2000-01-01

    The High Plains is a major agricultural area, supported primarily by water from the High Plains aquifer, which is used to irrigate wheat and corn and to raise cattle and swine. The U.S. Geological Survey (USGS) and the Oklahoma Water Resources Board (OWRB) began a study of the High Plains aquifer in 1996. One purpose of the study was to develop a ground-water flow model that the OWRB could use to allocate the amount of water withdrawn from the a aquifer. The study area in Oklahoma covers all or parts of Beaver, Cimarron, Dewey, Ellis, Harper, Texas, and Woodward Counties. To provide appropriate hydrologic boundaries for the ground-water flow model, the study area was expanded to include parts of Colorado, Kansas, New Mexico, and Texas.

  3. High-flaps for natural laminar flow airfoils

    NASA Technical Reports Server (NTRS)

    Morgan, Harry L.

    1986-01-01

    A review of the NACA and NASA low-drag airfoil research is presented with particular emphasis given to the development of mechanical high-lift flap systems and their application to general aviation aircraft. These flap systems include split, plain, single-slotted, and double-slotted trailing-edge flaps plus slat and Krueger leading-edge devices. The recently developed continuous variable-camber high-lift mechanism is also described. The state-of-the-art of theoretical methods for the design and analysis of multi-component airfoils in two-dimensional subsonic flow is discussed, and a detailed description of the Langley MCARF (Multi-Component Airfoil Analysis Program) computer code is presented. The results of a recent effort to design a single- and double-slotted flap system for the NASA high speed natural laminar flow (HSNLF) (1)-0213 airfoil using the MCARF code are presented to demonstrate the capabilities and limitations of the code.

  4. Rotating plane Couette flow at high rotation number

    NASA Astrophysics Data System (ADS)

    Suryadi, A.; Tillmark, N.; Alfredsson, P. H.

    2012-11-01

    Flow structures in the rotating plane Couette flow facility at KTH (described in Tsukahara, et al. J. Fluid Mech. vol. 648) have been studied at high rotation numbers. The test section is 20 mm wide with a length of 1500 mm in the streamwise (x) and 360 mm in the spanwise (z) directions and can be rotated in the spanwise direction up to angular velocities of Ωz ~ 0 . 6 rad/s. The flow is characterised by: (1) the Reynolds number Re based on the test section's half-width (h) and half of the velocity difference between the moving walls, (2) the rotation number Ω = 2Ωzh2 / ν . For low rotation numbers the primary instability consists of streamwise-oriented roll cells, but Tsukahara, et al. showed the secondary instability in the form of wavy streamwise oriented roll-cells at Re = 100 and Ω = 3 - 12 , whereas for higher Ω, the flow structures again stabilize to streamwise-oriented roll cells. Here we find that at even higher Ω in the range 40 - 70 , a new type of secondary instability develops in the form of counter-rotating helical roll-cells. The structure of this instability, as well as other instabilities, are investigated by flow visualization as well as two-dimensional PIV-measurements in several xz -planes.

  5. Label-free high-throughput imaging flow cytometry

    NASA Astrophysics Data System (ADS)

    Mahjoubfar, A.; Chen, C.; Niazi, K. R.; Rabizadeh, S.; Jalali, B.

    2014-03-01

    Flow cytometry is an optical method for studying cells based on their individual physical and chemical characteristics. It is widely used in clinical diagnosis, medical research, and biotechnology for analysis of blood cells and other cells in suspension. Conventional flow cytometers aim a laser beam at a stream of cells and measure the elastic scattering of light at forward and side angles. They also perform single-point measurements of fluorescent emissions from labeled cells. However, many reagents used in cell labeling reduce cellular viability or change the behavior of the target cells through the activation of undesired cellular processes or inhibition of normal cellular activity. Therefore, labeled cells are not completely representative of their unaltered form nor are they fully reliable for downstream studies. To remove the requirement of cell labeling in flow cytometry, while still meeting the classification sensitivity and specificity goals, measurement of additional biophysical parameters is essential. Here, we introduce an interferometric imaging flow cytometer based on the world's fastest continuous-time camera. Our system simultaneously measures cellular size, scattering, and protein concentration as supplementary biophysical parameters for label-free cell classification. It exploits the wide bandwidth of ultrafast laser pulses to perform blur-free quantitative phase and intensity imaging at flow speeds as high as 10 meters per second and achieves nanometer-scale optical path length resolution for precise measurements of cellular protein concentration.

  6. Modeling the interaction between flow and highly flexible aquatic vegetation

    NASA Astrophysics Data System (ADS)

    Dijkstra, J. T.; Uittenbogaard, R. E.

    2010-12-01

    Aquatic vegetation has an important role in estuaries and rivers by acting as bed stabilizer, filter, food source, and nursing area. However, macrophyte populations worldwide are under high anthropogenic pressure. Protection and restoration efforts will benefit from more insight into the interaction between vegetation, currents, waves, and sediment transport. Most aquatic plants are very flexible, implying that their shape and hence their drag and turbulence production depend on the flow conditions. We have developed a numerical simulation model that describes this dynamic interaction between very flexible vegetation and a time-varying flow, using the sea grass Zostera marina as an example. The model consists of two parts: an existing 1DV k-ɛ turbulence model simulating the flow combined with a new model simulating the bending of the plants, based on a force balance that takes account of both vegetation position and buoyancy. We validated this model using observations of positions of flexible plastic strips and of the forces they are subjected to, as well as hydrodynamic measurements. The model predicts important properties like the forces on plants, flow velocity profiles, and turbulence characteristics well. Although the validation data are limited, the results are sufficiently encouraging to consider our model to be of generic value in studying flow processes in fields of flexible vegetation.

  7. Laminated metal composite formed from low flow stress layers and high flow stress layers using flow constraining elements and making same

    DOEpatents

    Syn, Chol K.; Lesuer, Donald R.

    1995-01-01

    A laminated metal composite of low flow stress layers and high flow stress layers is described which is formed using flow constraining elements, preferably in the shape of rings, individually placed around each of the low flow stress layers while pressure is applied to the stack to bond the layers of the composite together, to thereby restrain the flow of the low flow stress layers from the stack during the bonding. The laminated metal composite of the invention is made by the steps of forming a stack of alternate layers of low flow stress layers and high flow stress layers with each layer of low flow stress material surrounded by an individual flow constraining element, such as a ring, and then applying pressure to the top and bottom surfaces of the resulting stack to bond the dissimilar layers together, for example, by compression rolling the stack. In a preferred embodiment, the individual flow constraining elements surrounding the layers of low flow stress material are formed of a material which may either be the same material as the material comprising the high flow stress layers, or have similar flow stress characteristics to the material comprising the high flow stress layers. Additional sacrificial layers may be added to the top and bottom of the stack to avoid damage to the stack during the bonding step; and these additional layers may then be removed after the bonding step.

  8. Laminated metal composite formed from low flow stress layers and high flow stress layers using flow constraining elements and making same

    DOEpatents

    Syn, C.K.; Lesuer, D.R.

    1995-07-04

    A laminated metal composite of low flow stress layers and high flow stress layers is described which is formed using flow constraining elements, preferably in the shape of rings, individually placed around each of the low flow stress layers while pressure is applied to the stack to bond the layers of the composite together, to thereby restrain the flow of the low flow stress layers from the stack during the bonding. The laminated metal composite of the invention is made by the steps of forming a stack of alternate layers of low flow stress layers and high flow stress layers with each layer of low flow stress material surrounded by an individual flow constraining element, such as a ring, and then applying pressure to the top and bottom surfaces of the resulting stack to bond the dissimilar layers together, for example, by compression rolling the stack. In a preferred embodiment, the individual flow constraining elements surrounding the layers of low flow stress material are formed of a material which may either be the same material as the material comprising the high flow stress layers, or have similar flow stress characteristics to the material comprising the high flow stress layers. Additional sacrificial layers may be added to the top and bottom of the stack to avoid damage to the stack during the bonding step; and these additional layers may then be removed after the bonding step. 5 figs.

  9. Morphological abnormalities in elasmobranchs.

    PubMed

    Moore, A B M

    2015-08-01

    A total of 10 abnormal free-swimming (i.e., post-birth) elasmobranchs are reported from The (Persian-Arabian) Gulf, encompassing five species and including deformed heads, snouts, caudal fins and claspers. The complete absence of pelvic fins in a milk shark Rhizoprionodon acutus may be the first record in any elasmobranch. Possible causes, including the extreme environmental conditions and the high level of anthropogenic pollution particular to The Gulf, are briefly discussed.

  10. The high Reynolds number flow through an axial-flow pump

    NASA Astrophysics Data System (ADS)

    Zierke, W. C.; Straka, W. A.; Taylor, P. D.

    1993-11-01

    The high Reynolds number pump (HIREP) facility at ARL Penn State has been used to perform a low-speed, large-scale experiment of the incompressible flow of water through a two-blade-row turbomachine. HIREP can involve blade chord Reynolds numbers as high as 6,000,000 and can accommodate a variety of instrumentation in both a stationary and a rotating frame of reference. The objectives of this experiment were as follows: to provide a database for comparison with three-dimensional, viscous (turbulent) flow computations; to evaluate the engineering models; and to improve our physical understanding of many of the phenomena involved in this complex flow field. The experimental results include a large quantity of data acquired throughout HIREP. A five-hole probe survey of the inlet flow 37.0 percent chord upstream of the inlet guide vane (IGV) leading edge is sufficient to give information for the inflow boundary conditions, while some static-pressure information is available to help establish an outflow boundary condition.

  11. Numerical Simulation of a High Mach Number Jet Flow

    NASA Technical Reports Server (NTRS)

    Hayder, M. Ehtesham; Turkel, Eli; Mankbadi, Reda R.

    1993-01-01

    The recent efforts to develop accurate numerical schemes for transition and turbulent flows are motivated, among other factors, by the need for accurate prediction of flow noise. The success of developing high speed civil transport plane (HSCT) is contingent upon our understanding and suppression of the jet exhaust noise. The radiated sound can be directly obtained by solving the full (time-dependent) compressible Navier-Stokes equations. However, this requires computational storage that is beyond currently available machines. This difficulty can be overcome by limiting the solution domain to the near field where the jet is nonlinear and then use acoustic analogy (e.g., Lighthill) to relate the far-field noise to the near-field sources. The later requires obtaining the time-dependent flow field. The other difficulty in aeroacoustics computations is that at high Reynolds numbers the turbulent flow has a large range of scales. Direct numerical simulations (DNS) cannot obtain all the scales of motion at high Reynolds number of technological interest. However, it is believed that the large scale structure is more efficient than the small-scale structure in radiating noise. Thus, one can model the small scales and calculate the acoustically active scales. The large scale structure in the noise-producing initial region of the jet can be viewed as a wavelike nature, the net radiated sound is the net cancellation after integration over space. As such, aeroacoustics computations are highly sensitive to errors in computing the sound sources. It is therefore essential to use a high-order numerical scheme to predict the flow field. The present paper presents the first step in a ongoing effort to predict jet noise. The emphasis here is in accurate prediction of the unsteady flow field. We solve the full time-dependent Navier-Stokes equations by a high order finite difference method. Time accurate spatial simulations of both plane and axisymmetric jet are presented. Jet Mach

  12. Secondary flow effects in high tip speed free convection

    SciTech Connect

    Eckels, P.W.; Parker, J.H. Jr.; Patterson, A. )

    1987-02-01

    Experimental analyses of the effects of secondary flows on heat transfer in high tip speed rotating apparatus are not readily available. This paper provides data on the heat transfer within two different test modules which were rotated at high speed with the heat transfer surfaces perpendicular and parallel to the Coriolis acceleration. One module contained a heated wall and another a parallel plate free convection experiment. Uniform heat fluxes were maintained. Rayeigh numbers in excess of 10{sup 15} were achieved with liquid helium as the transfer medium. Some of the findings are that secondary flows can reduce heat transfer by as much as 60% in single-phase heat transfer, the transitions to fully turbulent flow are in agreement with existing prediction methods, the critical heat flux in two-phase flow boiling is significantly increased, forced convection correlations underpredict single-phase thermosyphon performance, and the usual nondimensional parameters of free convection establish similitude between various fluids and speeds. These results suggest that techniques used to enhance heat transfer in the rotating frame should be verified by tests in the rotating frame.

  13. High-order filtering for control volume flow simulation

    NASA Astrophysics Data System (ADS)

    de Stefano, G.; Denaro, F. M.; Riccardi, G.

    2001-12-01

    A general methodology is presented in order to obtain a hierarchy of high-order filter functions, starting from the standard top-hat filter, naturally linked to control volumes flow simulations. The goal is to have a new filtered variable better represented in its high resolved wavenumber components by using a suitable deconvolution. The proposed formulation is applied to the integral momentum equation, that is the evolution equation for the top-hat filtered variable, by performing a spatial reconstruction based on the approximate inversion of the averaging operator. A theoretical analysis for the Burgers' model equation is presented, demonstrating that the local de-averaging is an effective tool to obtain a higher-order accuracy. It is also shown that the subgrid-scale term, to be modeled in the deconvolved balance equation, has a smaller absolute importance in the resolved wavenumber range for increasing deconvolution order. A numerical analysis of the procedure is presented, based on high-order upwind and central fluxes reconstruction, leading to congruent control volume schemes. Finally, the features of the present high-order conservative formulation are tested in the numerical simulation of a sample turbulent flow: the flow behind a backward-facing step. Copyright

  14. Genotype Distribution of Human Papillomavirus among Women with Cervical Cytological Abnormalities or Invasive Squamous Cell Carcinoma in a High-Incidence Area of Esophageal Carcinoma in China.

    PubMed

    Wang, Yuanyuan; Wang, Shaohong; Shen, Jinhui; Peng, Yanyan; Chen, Lechuan; Mai, Ruiqin; Zhang, Guohong

    2016-01-01

    Data of HPV genotype including 16 high-risk HPV (HR-HPV) and 4 low-risk HPV from 38,397 women with normal cytology, 1341 women with cervical cytology abnormalities, and 223 women with ISCC were retrospectively evaluated by a hospital-based study. The prevalence of high-risk HPV (HR-HPV) was 6.51%, 41.83%, and 96.86% in women with normal cytology, cervical cytology abnormalities, and ISCC, respectively. The three most common HPV types were HPV-52 (1.76%), HPV-16 (1.28%), and HPV-58 (0.97%) in women with normal cytology, whereas the most prevalent HPV type was HPV-16 (16.85%), followed by HPV-52 (9.55%) and HPV-58 (7.83%) in women with cervical cytology abnormalities. Specifically, HPV-16 had the highest frequency in ASC-H (24.16%, 36/149) and HSIL (35.71%, 110/308), while HPV-52 was the most common type in ASC-US (8.28%, 53/640) and LSIL (16.80%, 41/244). HPV-16 (75.78%), HPV18 (10.31%), and HPV58 (9.87%) were the most common types in women with ISCC. These data might contribute to increasing the knowledge of HPV epidemiology and providing the guide for vaccine selection for women in Shantou. PMID:27610364

  15. Genotype Distribution of Human Papillomavirus among Women with Cervical Cytological Abnormalities or Invasive Squamous Cell Carcinoma in a High-Incidence Area of Esophageal Carcinoma in China

    PubMed Central

    Wang, Yuanyuan; Wang, Shaohong; Shen, Jinhui; Peng, Yanyan; Chen, Lechuan; Mai, Ruiqin

    2016-01-01

    Data of HPV genotype including 16 high-risk HPV (HR-HPV) and 4 low-risk HPV from 38,397 women with normal cytology, 1341 women with cervical cytology abnormalities, and 223 women with ISCC were retrospectively evaluated by a hospital-based study. The prevalence of high-risk HPV (HR-HPV) was 6.51%, 41.83%, and 96.86% in women with normal cytology, cervical cytology abnormalities, and ISCC, respectively. The three most common HPV types were HPV-52 (1.76%), HPV-16 (1.28%), and HPV-58 (0.97%) in women with normal cytology, whereas the most prevalent HPV type was HPV-16 (16.85%), followed by HPV-52 (9.55%) and HPV-58 (7.83%) in women with cervical cytology abnormalities. Specifically, HPV-16 had the highest frequency in ASC-H (24.16%, 36/149) and HSIL (35.71%, 110/308), while HPV-52 was the most common type in ASC-US (8.28%, 53/640) and LSIL (16.80%, 41/244). HPV-16 (75.78%), HPV18 (10.31%), and HPV58 (9.87%) were the most common types in women with ISCC. These data might contribute to increasing the knowledge of HPV epidemiology and providing the guide for vaccine selection for women in Shantou. PMID:27610364

  16. Genotype Distribution of Human Papillomavirus among Women with Cervical Cytological Abnormalities or Invasive Squamous Cell Carcinoma in a High-Incidence Area of Esophageal Carcinoma in China

    PubMed Central

    Wang, Yuanyuan; Wang, Shaohong; Shen, Jinhui; Peng, Yanyan; Chen, Lechuan; Mai, Ruiqin

    2016-01-01

    Data of HPV genotype including 16 high-risk HPV (HR-HPV) and 4 low-risk HPV from 38,397 women with normal cytology, 1341 women with cervical cytology abnormalities, and 223 women with ISCC were retrospectively evaluated by a hospital-based study. The prevalence of high-risk HPV (HR-HPV) was 6.51%, 41.83%, and 96.86% in women with normal cytology, cervical cytology abnormalities, and ISCC, respectively. The three most common HPV types were HPV-52 (1.76%), HPV-16 (1.28%), and HPV-58 (0.97%) in women with normal cytology, whereas the most prevalent HPV type was HPV-16 (16.85%), followed by HPV-52 (9.55%) and HPV-58 (7.83%) in women with cervical cytology abnormalities. Specifically, HPV-16 had the highest frequency in ASC-H (24.16%, 36/149) and HSIL (35.71%, 110/308), while HPV-52 was the most common type in ASC-US (8.28%, 53/640) and LSIL (16.80%, 41/244). HPV-16 (75.78%), HPV18 (10.31%), and HPV58 (9.87%) were the most common types in women with ISCC. These data might contribute to increasing the knowledge of HPV epidemiology and providing the guide for vaccine selection for women in Shantou.

  17. High geothermal heat flow, Basal melt, and the origin of rapid ice flow in central Greenland.

    PubMed

    Fahnestock, M; Abdalati, W; Joughin, I; Brozena, J; Gogineni, P

    2001-12-14

    Age-depth relations from internal layering reveal a large region of rapid basal melting in Greenland. Melt is localized at the onset of rapid ice flow in the large ice stream that drains north off the summit dome and other areas in the northeast quadrant of the ice sheet. Locally, high melt rates indicate geothermal fluxes 15 to 30 times continental background. The southern limit of melt coincides with magnetic anomalies and topography that suggest a volcanic origin. PMID:11743197

  18. Post traumatic prepubertal high-flow priapism: a rare occurrence.

    PubMed

    Chung, Eric; McKnight, John; Hosken, Bruce

    2008-03-01

    High-flow or arterial priapism is an uncommon condition resulting from perineal or penile trauma. The classical features are a painless erection of the cavernous bodies while the corpus spongiosum stays flaccid. This case highlights a 11-year-old boy who presented with painless semi rigid erection of 3 days duration following a blunt skateboard injury to his perineum. Following failed conservative treatment, the patient underwent bilateral internal pudendal angiography with localization and embolization. Follow up in 1 month showed patient to have normal nocturnal and reflexogenic erections. Medical and surgical treatments for high-flow priapism have been described in literature with varying degree of success and complications. The current accepted standard of care is pelvic angiography and super-selective embolization of internal pudendal artery.

  19. Lithium-Based High Energy Density Flow Batteries

    NASA Technical Reports Server (NTRS)

    Bugga, Ratnakumar V. (Inventor); West, William C. (Inventor); Kindler, Andrew (Inventor); Smart, Marshall C. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement a lithium-based high energy density flow battery. In one embodiment, a lithium-based high energy density flow battery includes a first anodic conductive solution that includes a lithium polyaromatic hydrocarbon complex dissolved in a solvent, a second cathodic conductive solution that includes a cathodic complex dissolved in a solvent, a solid lithium ion conductor disposed so as to separate the first solution from the second solution, such that the first conductive solution, the second conductive solution, and the solid lithium ionic conductor define a circuit, where when the circuit is closed, lithium from the lithium polyaromatic hydrocarbon complex in the first conductive solution dissociates from the lithium polyaromatic hydrocarbon complex, migrates through the solid lithium ionic conductor, and associates with the cathodic complex of the second conductive solution, and a current is generated.

  20. High-throughput flow cytometry for drug discovery.

    PubMed

    Edwards, Bruce S; Young, Susan M; Saunders, Matthew J; Bologa, Cristian; Oprea, Tudor I; Ye, Richard D; Prossnitz, Eric R; Graves, Steven W; Sklar, Larry A

    2007-05-01

    High-throughput flow cytometry exploits a novel many-samples/one-file approach to dramatically speed data acquisition, limit aspirated sample volume to as little as 2 μl/well and produce multisample data sets that facilitate automated analysis of samples in groups as well as individually. It has been successfully applied to both cell- and microsphere-based bioassays in 96- and 384-well formats, to screen tens-of-thousands of compounds and identify novel bioactive structures. High-content multiparametric analysis capabilities have been exploited for assay multiplexing, allowing the assessment of biologic selectivity and specificity to be an integral component of primary screens. These and other advances in the last decade have contributed to the application of flow cytometry as a uniquely powerful tool for probing biologic and chemical diversity and complex systems biology.

  1. Abnormal pressure in hydrocarbon environments

    USGS Publications Warehouse

    Law, B.E.; Spencer, C.W.

    1998-01-01

    Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

  2. Calibration of high flow rate thoracic-size selective samplers

    PubMed Central

    Lee, Taekhee; Thorpe, Andrew; Cauda, Emanuele; Harper, Martin

    2016-01-01

    High flow rate respirable size selective samplers, GK4.126 and FSP10 cyclones, were calibrated for thoracic-size selective sampling in two different laboratories. The National Institute for Occupational Safety and Health (NIOSH) utilized monodisperse ammonium fluorescein particles and scanning electron microscopy to determine the aerodynamic particle size of the monodisperse aerosol. Fluorescein intensity was measured to determine sampling efficiencies of the cyclones. The Health Safety and Laboratory (HSL) utilized a real time particle sizing instrument (Aerodynamic Particle Sizer) and poly-disperse glass sphere particles and particle size distributions between the cyclone and reference sampler were compared. Sampling efficiency of the cyclones were compared to the thoracic convention defined by the American Conference of Governmental Industrial Hygienists (ACGIH)/Comité Européen de Normalisation (CEN)/International Standards Organization (ISO). The GK4.126 cyclone showed minimum bias compared to the thoracic convention at flow rates of 3.5 l min−1 (NIOSH) and 2.7–3.3 l min−1 (HSL) and the difference may be from the use of different test systems. In order to collect the most dust and reduce the limit of detection, HSL suggested using the upper end in range (3.3 l min−1). A flow rate of 3.4 l min−1 would be a reasonable compromise, pending confirmation in other laboratories. The FSP10 cyclone showed minimum bias at the flow rate of 4.0 l min−1 in the NIOSH laboratory test. The high flow rate thoracic-size selective samplers might be used for higher sample mass collection in order to meet analytical limits of quantification. PMID:26891196

  3. Calibration of high flow rate thoracic-size selective samplers.

    PubMed

    Lee, Taekhee; Thorpe, Andrew; Cauda, Emanuele; Harper, Martin

    2016-01-01

    High flow rate respirable size selective samplers, GK4.126 and FSP10 cyclones, were calibrated for thoracic-size selective sampling in two different laboratories. The National Institute for Occupational Safety and Health (NIOSH) utilized monodisperse ammonium fluorescein particles and scanning electron microscopy to determine the aerodynamic particle size of the monodisperse aerosol. Fluorescein intensity was measured to determine sampling efficiencies of the cyclones. The Health Safety and Laboratory (HSL) utilized a real time particle sizing instrument (Aerodynamic Particle Sizer) and polydisperse glass sphere particles and particle size distributions between the cyclone and reference sampler were compared. Sampling efficiency of the cyclones were compared to the thoracic convention defined by the American Conference of Governmental Industrial Hygienists (ACGIH)/Comité Européen de Normalisation (CEN)/International Standards Organization (ISO). The GK4.126 cyclone showed minimum bias compared to the thoracic convention at flow rates of 3.5 l min(-1) (NIOSH) and 2.7-3.3 l min(-1) (HSL) and the difference may be from the use of different test systems. In order to collect the most dust and reduce the limit of detection, HSL suggested using the upper end in range (3.3 l min(-1)). A flow rate of 3.4 l min(-1) would be a reasonable compromise, pending confirmation in other laboratories. The FSP10 cyclone showed minimum bias at the flow rate of 4.0 l min(-1) in the NIOSH laboratory test. The high flow rate thoracic-size selective samplers might be used for higher sample mass collection in order to meet analytical limits of quantification. PMID:26891196

  4. Stability of boundary layers within high-speed viscous flows

    NASA Astrophysics Data System (ADS)

    Lyttle, Ian John

    2003-10-01

    A numerical study was undertaken to predict the stability of a variety of high-speed boundary-layer flows. Using a finite-volume code, the Navier-Stokes equations were solved for a series of flows around spherically blunted cones. These solutions were used to perform linear-stability analyses for second-mode disturbances. Two investigations were undertaken using an ideal-gas model: the Stetson experiment and a recent experiment conducted at the Institute of Theoretical and Applied Mechanics in Russia. Comparisons were made with both basic-state and disturbance state quantities. For both cases, linear-growth regions have been identified. For the Stetson case, using an experimentally determined wall-temperature distribution for the basic-state appeared to give better agreement with the experimentally measured growth than does the classical adiabatic-wall boundary condition. For the Russian experiment, initial comparisons were made in order to continue a careful collaboration. A third investigation was made which used a chemical non-equilibrium model, considering a Mach 13.5 flow in upper-atmospheric conditions. The goal of this investigation was to evaluate the sensitivity of second-mode growth predictions to changes (within accepted uncertainties) in thermodynamic, reaction-rate; and transport models. The magnitude of change in the stability results correlated strongly with changes in the basic-state thermal boundary-layer profile, consistent with second-mode theory. The largest change in the stability behavior was observed for the case where the transport model was changed. For high-speed flows, the development of computational techniques is in some ways ahead of the experimental community's ability to verify the results. As these techniques are applied to flows in thermochemical non-equilibrium, the fidelity of the constitutive relationships should be considered.

  5. Very High Resolution Simulations of Compressible, Turbulent Flows

    SciTech Connect

    Woodward, P R; Porter, D H; Sytine, I; Anderson, S E; Mirin, A A; Curtis, B C; Cohen, R H; Dannevik, W P; Dimits, A M; Eliason, D E; Winkler, K-H; Hodson, S W

    2001-04-26

    The steadily increasing power of supercomputing systems is enabling very high resolution simulations of compressible, turbulent flows in the high Reynolds number limit, which is of interest in astrophysics as well as in several other fluid dynamical applications. This paper discusses two such simulations, using grids of up to 8 billion cells. In each type of flow, convergence in a statistical sense is observed as the mesh is refined. The behavior of the convergent sequences indicates how a subgrid-scale model of turbulence could improve the treatment of these flows by high-resolution Euler schemes like PPM. The best resolved case, a simulation of a Richtmyer-Meshkov mixing layer in a shock tube experiment, also points the way toward such a subgrid-scale model. Analysis of the results of that simulation indicates a proportionality relationship between the energy transfer rate from large to small motions and the determinant of the deviatoric symmetric strain as well as the divergence of the velocity for the large-scale field.

  6. Refraction of high frequency noise in an arbitrary jet flow

    NASA Technical Reports Server (NTRS)

    Khavaran, Abbas; Krejsa, Eugene A.

    1994-01-01

    Refraction of high frequency noise by mean flow gradients in a jet is studied using the ray-tracing methods of geometrical acoustics. Both the two-dimensional (2D) and three-dimensional (3D) formulations are considered. In the former case, the mean flow is assumed parallel and the governing propagation equations are described by a system of four first order ordinary differential equations. The 3D formulation, on the other hand, accounts for the jet spreading as well as the axial flow development. In this case, a system of six first order differential equations are solved to trace a ray from its source location to an observer in the far field. For subsonic jets with a small spreading angle both methods lead to similar results outside the zone of silence. However, with increasing jet speed the two prediction models diverge to the point where the parallel flow assumption is no longer justified. The Doppler factor of supersonic jets as influenced by the refraction effects is discussed and compared with the conventional modified Doppler factor.

  7. Development and Application of Plasma Actuators for Active Control of High-Speed and High Reynolds Number Flows

    NASA Technical Reports Server (NTRS)

    Sammy, Mo

    2010-01-01

    Active flow control is often used to manipulate flow instabilities to achieve a desired goal (e.g. prevent separation, enhance mixing, reduce noise, etc.). Instability frequencies normally scale with flow velocity scale and inversely with flow length scale (U/l). In a laboratory setting for such flow experiments, U is high, but l is low, resulting in high instability frequency. In addition, high momentum and high background noise & turbulence in the flow necessitate high amplitude actuation. Developing a high amplitude and high frequency actuator is a major challenge. Ironically, these requirements ease up in application (but other issues arise).

  8. Left globus pallidus abnormality in never-medicated patients with schizophrenia

    SciTech Connect

    Early, T.S.; Reiman, E.M.; Raichle, M.E.; Spitznagel, E.L.

    1987-01-01

    Schizophrenia is a severe psychiatric disorder characterized by onset in young adulthood, the occurrence of hallucinations and delusions, and the development of enduring psychosocial disability. The pathophysiology of this disorder remains unknown. Studies of cerebral blood flow and metabolism designed to identify brain abnormalities in schizophrenia have been limited by inadequate methods of anatomical localization and the possibility of persistent medication effects. The authors have now used positron emission tomography and a validated method of anatomical localization in an attempt to identify abnormalities of regional cerebral blood flow in newly diagnosed never-medicated patients with schizophrenia. An exploratory study of 5 patients and 10 normal control subjects identified abnormally high blood flow in the left globus pallidus of patients with schizophrenia. A replication study of 5 additional patients and 10 additional control subjects confirmed this finding. No other abnormalities were found.

  9. Modeling Compressibility Effects in High-Speed Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Sarkar, S.

    2004-01-01

    Man has strived to make objects fly faster, first from subsonic to supersonic and then to hypersonic speeds. Spacecraft and high-speed missiles routinely fly at hypersonic Mach numbers, M greater than 5. In defense applications, aircraft reach hypersonic speeds at high altitude and so may civilian aircraft in the future. Hypersonic flight, while presenting opportunities, has formidable challenges that have spurred vigorous research and development, mainly by NASA and the Air Force in the USA. Although NASP, the premier hypersonic concept of the eighties and early nineties, did not lead to flight demonstration, much basic research and technology development was possible. There is renewed interest in supersonic and hypersonic flight with the HyTech program of the Air Force and the Hyper-X program at NASA being examples of current thrusts in the field. At high-subsonic to supersonic speeds, fluid compressibility becomes increasingly important in the turbulent boundary layers and shear layers associated with the flow around aerospace vehicles. Changes in thermodynamic variables: density, temperature and pressure, interact strongly with the underlying vortical, turbulent flow. The ensuing changes to the flow may be qualitative such as shocks which have no incompressible counterpart, or quantitative such as the reduction of skin friction with Mach number, large heat transfer rates due to viscous heating, and the dramatic reduction of fuel/oxidant mixing at high convective Mach number. The peculiarities of compressible turbulence, so-called compressibility effects, have been reviewed by Fernholz and Finley. Predictions of aerodynamic performance in high-speed applications require accurate computational modeling of these "compressibility effects" on turbulence. During the course of the project we have made fundamental advances in modeling the pressure-strain correlation and developed a code to evaluate alternate turbulence models in the compressible shear layer.

  10. Treatment of High-Flow Vascular Malformations by Venous Embolization Aided by Flow Occlusion Techniques

    SciTech Connect

    Jackson, James E.; Mansfield, Averil O.; Allison, David J.

    1996-09-15

    Purpose: Transvenous embolization techniques may be helpful as alternatives to the arterial route when treating high-flow vascular malformations. We present our experience using these techniques in four patients. Methods: In one patient the venous portion of the arteriovenous malformation (AVM) was punctured directly; in the other three patients it was catheterized via a retrograde venous approach. Flow occlusion techniques were utilized in all patients during embolization, which was performed with absolute alcohol or N-butyl-2-cyanoacrylate.Results: Excellent clinical and angiographic results were obtained, with obliteration of arteriovenous shunting in all patients. There were no complications.Conclusion: The embolization of certain AVMs using a venous approach is a safe and effective treatment.

  11. Transient flow characteristics of a high speed rotary valve

    NASA Astrophysics Data System (ADS)

    Browning, Patrick H.

    were experimentally mapped as a function of valve speed, inter-cylinder pressure ratios and volume ratios and the results were compared to compressible flow theoretical models. Specifically, the transient behavior suggested a short-lived loss-mode initiation closely resembled by shock tube theory followed by a quasi-steady flow regime resembling choked flow behavior. An empirical model was then employed to determine the useful range of the CCV design as applied to a four-stroke CIBAI engine cycle modeled using a 1-D quasi-steady numerical method, with particular emphasis on the cyclic timing of the CCV opening. Finally, a brief discussion of a high-temperature version of the CCV design is presented.

  12. High speed optical holography of retinal blood flow.

    PubMed

    Pellizzari, M; Simonutti, M; Degardin, J; Sahel, J-A; Fink, M; Paques, M; Atlan, M

    2016-08-01

    We performed noninvasive video imaging of retinal blood flow in a pigmented rat by holographic interferometry of near-infrared laser light backscattered by retinal tissue, beating against an off-axis reference beam sampled at a frame rate of 39 kHz with a high throughput camera. Local Doppler contrasts emerged from the envelopes of short-time Fourier transforms and the phase of autocorrelation functions of holograms rendered by Fresnel transformation. This approach permitted imaging of blood flow in large retinal vessels (∼30 microns diameter) over 400×400  pixels with a spatial resolution of ∼8 microns and a temporal resolution of ∼6.5  ms. PMID:27472604

  13. High Reynolds number decay of turbulent Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    Verschoof, Ruben A.; Huisman, Sander G.; van der Veen, Roeland C. A.; Sun, Chao; Lohse, Detlef

    2015-11-01

    We study the decay of high-Reynolds number turbulence in a Taylor-Couette facility for pure inner cylinder rotation. The rotation of the inner cylinder (Rei = 2 ×106) is suddenly decelerated as fast as possible, thus removing the energy input within seconds. Local velocity measurements show that the decay in this wall-bounded inhomogeneous flow is faster than observed for homogeneous isotropic turbulent flows, due to the strong viscous drag applied by the inner and outer cylinder surfaces. We found that the decay over time can be described with the differential equation Re . (t) =cf (Re)Re2 , where the effects of the walls are included through the friction coefficient. A self-similar behavior of the azimuthal velocity is found: its normalized velocity profile as a function of the radius collapses over time during the decay process.

  14. Highly efficient electroosmotic flow through functionalized carbon nanotube membranes

    NASA Astrophysics Data System (ADS)

    Wu, Ji; Gerstandt, Karen; Majumder, Mainak; Zhan, Xin; Hinds, Bruce J.

    2011-08-01

    Carbon nanotube membranes with inner diameter ranging from 1.5-7 nm were examined for enhanced electroosmotic flow. After functionalization via electrochemical diazonium grafting and carbodiimide coupling reaction, it was found that neutral caffeine molecules can be efficiently pumped via electroosmosis. An electroosmotic velocity as high as 0.16 cm s-1 V-1 has been observed. Power efficiencies were 25-110 fold improved compared to related nanoporous materials, which has important applications in chemical separations and compact medical devices. Nearly ideal electroosmotic flow was seen in the case where the mobile cation diameter nearly matched the inner diameter of the single-walled carbon nanotube resulting in a condition of using one ion is to pump one neutral molecule at equivalent concentrations.

  15. High speed optical holography of retinal blood flow.

    PubMed

    Pellizzari, M; Simonutti, M; Degardin, J; Sahel, J-A; Fink, M; Paques, M; Atlan, M

    2016-08-01

    We performed noninvasive video imaging of retinal blood flow in a pigmented rat by holographic interferometry of near-infrared laser light backscattered by retinal tissue, beating against an off-axis reference beam sampled at a frame rate of 39 kHz with a high throughput camera. Local Doppler contrasts emerged from the envelopes of short-time Fourier transforms and the phase of autocorrelation functions of holograms rendered by Fresnel transformation. This approach permitted imaging of blood flow in large retinal vessels (∼30 microns diameter) over 400×400  pixels with a spatial resolution of ∼8 microns and a temporal resolution of ∼6.5  ms.

  16. Turbulence and transition modeling for high-speed flows

    NASA Technical Reports Server (NTRS)

    Wilcox, David C.

    1993-01-01

    Research conducted during the past three and a half years aimed at developing and testing a turbulence/transition model applicable to high-speed turbulent flows is summarized. The first two years of the project focused on fully turbulent flows, while emphasis shifted to boundary-layer development in the transition region during the final year and a half. A brief summary of research accomplished during the first three years is included and publications that describe research results in greater detail are cited. Research conducted during the final six months of the period of performance is summarized. The primary results of the last six months of the project are elimination of the k-omega model's sensitivity to the freestream value of omega and development of a method for triggering transition at a specified location, independent of the freestream turbulence level.

  17. Modeling and simulation of high-speed wake flows

    NASA Astrophysics Data System (ADS)

    Barnhardt, Michael Daniel

    High-speed, unsteady flows represent a unique challenge in computational hypersonics research. They are found in nearly all applications of interest, including the wakes of reentry vehicles, RCS jet interactions, and scramjet combustors. In each of these examples, accurate modeling of the flow dynamics plays a critical role in design performance. Nevertheless, literature surveys reveal that very little modern research effort has been made toward understanding these problems. The objective of this work is to synthesize current computational methods for high-speed flows with ideas commonly used to model low-speed, turbulent flows in order to create a framework by which we may reliably predict unsteady, hypersonic flows. In particular, we wish to validate the new methodology for the case of a turbulent wake flow at reentry conditions. Currently, heat shield designs incur significant mass penalties due to the large margins applied to vehicle afterbodies in lieu of a thorough understanding of the wake aerothermodynamics. Comprehensive validation studies are required to accurately quantify these modeling uncertainties. To this end, we select three candidate experiments against which we evaluate the accuracy of our methodology. The first set of experiments concern the Mars Science Laboratory (MSL) parachute system and serve to demonstrate that our implementation produces results consistent with prior studies at supersonic conditions. Second, we use the Reentry-F flight test to expand the application envelope to realistic flight conditions. Finally, in the last set of experiments, we examine a spherical capsule wind tunnel configuration in order to perform a more detailed analysis of a realistic flight geometry. In each case, we find that current 1st order in time, 2nd order in space upwind numerical methods are sufficiently accurate to predict statistical measurements: mean, RMS, standard deviation, and so forth. Further potential gains in numerical accuracy are

  18. Assessment of transmitral flow after mitral valve edge-to-edge repair using High-speed particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Jeyhani, Morteza; Shahriari, Shahrokh; Labrosse, Michel; Kadem, Lyes

    2013-11-01

    Approximately 500,000 people in North America suffer from mitral valve regurgitation (MR). MR is a disorder of the heart in which the mitral valve (MV) leaflets do not close securely during systole. Edge-to-edge repair (EtER) technique can be used to surgically treat MR. This technique produces a double-orifice configuration for the MV. Under these un-physiological conditions, flow downstream of the MV forms a double jet structure that may disturb the intraventricular hemodynamics. Abnormal flow patterns following EtER are mainly characterized by high-shear stress and stagnation zones in the left ventricle (LV), which increase the potential of blood component damage. In this study, a custom-made prosthetic bicuspid MV was used to analyze the LV flow patterns after EtER by means of digital particle image velocimetry (PIV). Although the repair of a MV using EtER technique is an effective approach, this study confirms that EtER leads to changes in the LV flow field, including the generation of a double mitral jet flow and high shear stress regions.

  19. High-Speed Unsteady Flows around Concave Axisymmetric Bodies: Flow Instabilities and their Suppression

    NASA Astrophysics Data System (ADS)

    Panaras, A.; Drikakis, D.

    2009-01-01

    The axisymmetric concave body, i.e. a body in which the normals to its surface intersect, is a typical configuration about which shock/shock interactions appear. Various shapes of axisymmetric concave bodies are used in a variety of applications in aeronautics. For exampe: axisymmetric jet inlets with conical centerbody, ballistic missiles drag reduction by spike, plasma or hot gas injection, parachutes for pilot-ejection capsules. However, it is well known that two distinct modes of instability appear around a concave body in the high-speed flow regime, for a certain range of geometric parameters. These instabilities can cause undesirable effects such as severe vibration of the structure, heating and pressure loads. According to the experimental evidence, the unsteady flow is characterized by periodic radial inflation and collapse of the conical separation bubble formed around the forebody (pulsation). Various explanations have been given for the driving mechanism of the instabilities. They are based on interpretation of experimental results or on numerical simulation of the related flows. A merging of the leading explanations is done, and basic rules for the passive suppression of the instabilities are applied, in order to enforce the proposed driving mechanism of the instabilities. Most of the analysis is based on numerical simulations.

  20. Turbulence measurements in high-speed flows by resonant fluoresence

    NASA Technical Reports Server (NTRS)

    Miles, R. B.

    1982-01-01

    Both mean flow and turbulence measurements were investigated using the resonant Doppler velocimeter in a Mach 3.2 nitrogen flow. Data are presented showing velocity, temperature and pressure measured point by point across the flow field. This data is compared with conventional pitot and temperature surveys. Turbulence was induced by a small metal tab in the flow and observed by both hot wire and RDV techniques. Photographs of the flow field demonstrate the utility of the RDV for quantitative flow field visualization.

  1. Interaction of upstream flow distortions with high Mach number cascades

    NASA Technical Reports Server (NTRS)

    Englert, G. W.

    1981-01-01

    Features of the interaction of flow distortions, such as gusts and wakes with blade rows of advance type fans and compressors having high tip Mach numbers are modeled. A typical disturbance was assumed to have harmonic time dependence and was described, at a far upstream location, in three orthogonal spatial coordinates by a double Fourier series. It was convected at supersonic relative to a linear cascade described as an unrolled annulus. Conditions were selected so that the component of this velocity parallel to the axis of the turbomachine was subsonic, permitting interaction between blades through the upstream as well as downstream flow media. A strong, nearly normal shock was considered in the blade passages which was allowed curvature and displacement. The flows before and after the shock were linearized relative to uniform mean velocities in their respective regions. Solution of the descriptive equations was by adaption of the Wiener-Hopf technique, enabling a determination of distortion patterns through and downstream of the cascade as well as pressure distributions on the blade and surfaces. Details of interaction of the disturbance with the in-passage shock were discussed. Infuences of amplitude, wave length, and phase of the disturbance on lifts and moments of cascade configurations are presented. Numerical results are clarified by reference to an especially orderly pattern of upstream vertical motion in relation to the cascade parameters.

  2. Topology and grid adaption for high-speed flow computations

    NASA Technical Reports Server (NTRS)

    Abolhassani, Jamshid S.; Tiwari, Surendra N.

    1989-01-01

    This study investigates the effects of grid topology and grid adaptation on numerical solutions of the Navier-Stokes equations. In the first part of this study, a general procedure is presented for computation of high-speed flow over complex three-dimensional configurations. The flow field is simulated on the surface of a Butler wing in a uniform stream. Results are presented for Mach number 3.5 and a Reynolds number of 2,000,000. The O-type and H-type grids have been used for this study, and the results are compared together and with other theoretical and experimental results. The results demonstrate that while the H-type grid is suitable for the leading and trailing edges, a more accurate solution can be obtained for the middle part of the wing with an O-type grid. In the second part of this study, methods of grid adaption are reviewed and a method is developed with the capability of adapting to several variables. This method is based on a variational approach and is an algebraic method. Also, the method has been formulated in such a way that there is no need for any matrix inversion. This method is used in conjunction with the calculation of hypersonic flow over a blunt-nose body. A movie has been produced which shows simultaneously the transient behavior of the solution and the grid adaption.

  3. Experimental study of highly turbulent isothermal opposed-jet flows

    NASA Astrophysics Data System (ADS)

    Coppola, Gianfilippo; Gomez, Alessandro

    2010-10-01

    Opposed-jet flows have been shown to provide a valuable means to study a variety of combustion problems, but have been limited to either laminar or modestly turbulent conditions. With the ultimate goal of developing a burner for laboratory flames reaching turbulence regimes of relevance to practical systems, we characterized highly turbulent, strained, isothermal, opposed-jet flows using particle image velocimetry (PIV). The bulk strain rate was kept at 1250 s-1 and specially designed and properly positioned turbulence generation plates in the incoming streams boosted the turbulence intensity to well above 20%, under conditions that are amenable to flame stabilization. The data were analyzed with proper orthogonal decomposition (POD) and a novel statistical analysis conditioned to the instantaneous position of the stagnation surface. Both POD and the conditional analysis were found to be valuable tools allowing for the separation of the truly turbulent fluctuations from potential artifacts introduced by relatively low-frequency, large-scale instabilities that would otherwise partly mask the turbulence. These instabilities cause the stagnation surface to wobble with both an axial oscillation and a precession motion about the system axis of symmetry. Once these artifacts are removed, the longitudinal integral length scales are found to decrease as one approaches the stagnation line, as a consequence of the strained flow field, with the corresponding outer scale turbulent Reynolds number following a similar trend. The Taylor scale Reynolds number is found to be roughly constant throughout the flow field at about 200, with a value virtually independent of the data analysis technique. The novel conditional statistics allowed for the identification of highly convoluted stagnation lines and, in some cases, of strong three-dimensional effects, that can be screened, as they typically yield more than one stagnation line in the flow field. The ability to lock on the

  4. Numerical solution of compressible viscous flows at high Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Maccormack, R. W.

    1981-01-01

    A new numerical method which was used to reduce the computation time required in fluid dynamics to solve the Navier-Stokes equations at flight Reynolds numbers is described. The method is the implicit analogue of the explicit finite different method. It uses this as its first stage, while the second stage removes the restrictive stability condition by recasting the difference equations in an implicit form. The resulting matrix equations to be solved are either upper or lower block bidiagonal equations. The new method makes it possible and practical to calculate many important three dimensional, high Reynolds number flow fields on computers.

  5. Local isotropy in high Reynolds number turbulent shear flows

    NASA Technical Reports Server (NTRS)

    Saddoughi, Seyed G.

    1993-01-01

    This is a report on the continuation of experiments, which Dr. Srinivas Veeravalli and the present author started in 1991, to investigate the hypothesis of local isotropy in shear flows. This hypothesis, which states that at sufficiently high Reynolds numbers the small-scale structures of turbulent motions are independent of large-scale structures and mean deformations, has been used in theoretical studies of turbulence and computational methods like large-eddy simulation. The importance of Kolmogorov's ideas arises from the fact that they create a foundation for turbulence theory.

  6. High Prevalence of Chronic Pituitary and Target-Organ Hormone Abnormalities after Blast-Related Mild Traumatic Brain Injury

    PubMed Central

    Wilkinson, Charles W.; Pagulayan, Kathleen F.; Petrie, Eric C.; Mayer, Cynthia L.; Colasurdo, Elizabeth A.; Shofer, Jane B.; Hart, Kim L.; Hoff, David; Tarabochia, Matthew A.; Peskind, Elaine R.

    2011-01-01

    Studies of traumatic brain injury from all causes have found evidence of chronic hypopituitarism, defined by deficient production of one or more pituitary hormones at least 1 year after injury, in 25–50% of cases. Most studies found the occurrence of posttraumatic hypopituitarism (PTHP) to be unrelated to injury severity. Growth hormone deficiency (GHD) and hypogonadism were reported most frequently. Hypopituitarism, and in particular adult GHD, is associated with symptoms that resemble those of PTSD, including fatigue, anxiety, depression, irritability, insomnia, sexual dysfunction, cognitive deficiencies, and decreased quality of life. However, the prevalence of PTHP after blast-related mild TBI (mTBI), an extremely common injury in modern military operations, has not been characterized. We measured concentrations of 12 pituitary and target-organ hormones in two groups of male US Veterans of combat in Iraq or Afghanistan. One group consisted of participants with blast-related mTBI whose last blast exposure was at least 1 year prior to the study. The other consisted of Veterans with similar military deployment histories but without blast exposure. Eleven of 26, or 42% of participants with blast concussions were found to have abnormal hormone levels in one or more pituitary axes, a prevalence similar to that found in other forms of TBI. Five members of the mTBI group were found with markedly low age-adjusted insulin-like growth factor-I (IGF-I) levels indicative of probable GHD, and three had testosterone and gonadotropin concentrations consistent with hypogonadism. If symptoms characteristic of both PTHP and PTSD can be linked to pituitary dysfunction, they may be amenable to treatment with hormone replacement. Routine screening for chronic hypopituitarism after blast concussion shows promise for appropriately directing diagnostic and therapeutic decisions that otherwise may remain unconsidered and for markedly facilitating recovery and rehabilitation. PMID

  7. Probe measures gas and liquid mass flux in high mass flow ratio two-phase flows

    NASA Technical Reports Server (NTRS)

    Burick, R. J.

    1972-01-01

    Deceleration probe constructed of two concentric tubes with separator inlet operates successfully in flow fields where ratio of droplet flow rate to gas flow rate ranges from 1.0 to 20, and eliminates problems of local flow field disturbances and flooding. Probe is effective tool for characterization of liquid droplet/gas spray fields.

  8. CPAP and High-Flow Nasal Cannula Oxygen in Bronchiolitis.

    PubMed

    Sinha, Ian P; McBride, Antonia K S; Smith, Rachel; Fernandes, Ricardo M

    2015-09-01

    Severe respiratory failure develops in some infants with bronchiolitis because of a complex pathophysiologic process involving increased airways resistance, alveolar atelectasis, muscle fatigue, and hypoxemia due to mismatch between ventilation and perfusion. Nasal CPAP and high-flow nasal cannula (HFNC) oxygen may improve the work of breathing and oxygenation. Although the mechanisms behind these noninvasive modalities of respiratory support are not well understood, they may help infants by way of distending pressure and delivery of high concentrations of warmed and humidified oxygen. Observational studies of varying quality have suggested that CPAP and HFNC may confer direct physiologic benefits to infants with bronchiolitis and that their use has reduced the need for intubation. No trials to our knowledge, however, have compared CPAP with HFNC in bronchiolitis. Two randomized trials compared CPAP with oxygen delivered by low-flow nasal cannula or face mask and found some improvements in blood gas results and some physiologic parameters, but these trials were unable to demonstrate a reduction in the need for intubation. Two trials evaluated HFNC in bronchiolitis (one comparing it with headbox oxygen, the other with nebulized hypertonic saline), with the results not seeming to suggest important clinical or physiologic benefits. In this article, we review the pathophysiology of respiratory failure in bronchiolitis, discuss these trials in detail, and consider how future research studies may be designed to best evaluate CPAP and HFNC in bronchiolitis.

  9. High speed flow cytometer droplet formation system and method

    DOEpatents

    Van den Engh, Ger

    2000-01-01

    A droplet forming flow cytometer system allows high speed processing without the need for high oscillator drive powers through the inclusion of an oscillator or piezoelectric crystal such as within the nozzle volume or otherwise unidirectionally coupled to the sheath fluid. The nozzle container continuously converges so as to amplify unidirectional oscillations which are transmitted as pressure waves through the nozzle volume to the nozzle exit so as to form droplets from the fluid jet. The oscillator is directionally isolated so as to avoid moving the entire nozzle container so as to create only pressure waves within the sheath fluid. A variation in substance concentration is achieved through a movable substance introduction port which is positioned within a convergence zone to vary the relative concentration of substance to sheath fluid while still maintaining optimal laminar flow conditions. This variation may be automatically controlled through a sensor and controller configuration. A replaceable tip design is also provided whereby the ceramic nozzle tip is positioned within an edge insert in the nozzle body so as to smoothly transition from nozzle body to nozzle tip. The nozzle tip is sealed against its outer surface to the nozzle body so it may be removable for cleaning or replacement.

  10. CPAP and High-Flow Nasal Cannula Oxygen in Bronchiolitis.

    PubMed

    Sinha, Ian P; McBride, Antonia K S; Smith, Rachel; Fernandes, Ricardo M

    2015-09-01

    Severe respiratory failure develops in some infants with bronchiolitis because of a complex pathophysiologic process involving increased airways resistance, alveolar atelectasis, muscle fatigue, and hypoxemia due to mismatch between ventilation and perfusion. Nasal CPAP and high-flow nasal cannula (HFNC) oxygen may improve the work of breathing and oxygenation. Although the mechanisms behind these noninvasive modalities of respiratory support are not well understood, they may help infants by way of distending pressure and delivery of high concentrations of warmed and humidified oxygen. Observational studies of varying quality have suggested that CPAP and HFNC may confer direct physiologic benefits to infants with bronchiolitis and that their use has reduced the need for intubation. No trials to our knowledge, however, have compared CPAP with HFNC in bronchiolitis. Two randomized trials compared CPAP with oxygen delivered by low-flow nasal cannula or face mask and found some improvements in blood gas results and some physiologic parameters, but these trials were unable to demonstrate a reduction in the need for intubation. Two trials evaluated HFNC in bronchiolitis (one comparing it with headbox oxygen, the other with nebulized hypertonic saline), with the results not seeming to suggest important clinical or physiologic benefits. In this article, we review the pathophysiology of respiratory failure in bronchiolitis, discuss these trials in detail, and consider how future research studies may be designed to best evaluate CPAP and HFNC in bronchiolitis. PMID:25836649

  11. High-order Finite Element Analysis of Boundary Layer Flows

    NASA Astrophysics Data System (ADS)

    Zhang, Alvin; Sahni, Onkar

    2014-11-01

    Numerical analysis of boundary layer flows requires careful approximations, specifically the use of a mesh with layered and graded elements near the (viscous) walls. This is referred to as a boundary layer mesh, which for complex geometries is composed of triangular elements on the walls that are inflated or extruded into the volume along the wall-normal direction up to a desired height while the rest of the domain is filled with unstructured tetrahedral elements. Linear elements with C0 inter-element continuity are employed and in some situations higher order C0 elements are also used. However, these elements only enforce continuity whereas high-order smoothness is not attained as will be the case with C1 inter-element continuity and higher. As a result, C0 elements result in a poor approximation of the high-order boundary layer behavior. To achieve greater inter-element continuity in boundary layer region, we employ B-spline basis functions along the wall-normal direction (i.e., only in the layered portion of the mesh). In the rest of the fully unstructured mesh, linear or higher order C0 elements are used as appropriate. In this study we demonstrate the benefits of finite-element analysis based on such higher order and continuity basis functions for boundary layer flows.

  12. Hypertension, Abnormal Cholesterol, and High Body Mass Index among Non-Hispanic Asian Adults: United States, 2011-2012

    MedlinePlus

    ... high total cholesterol among non-Hispanic Asian adults did not differ by sex, age, education, or foreign- ... Figure 3 ). The prevalence of high total cholesterol did not differ significantly by sex, age, education, or ...

  13. High-redshift supermassive black holes: accretion through cold flows

    NASA Astrophysics Data System (ADS)

    Feng, Yu; Di Matteo, Tiziana; Croft, Rupert; Khandai, Nishikanta

    2014-05-01

    We use zoom-in techniques to re-simulate three high-redshift (z ≥ 5.5) haloes which host 109 M⊙ black holes from the ˜Gpc volume, MassiveBlack cosmological hydrodynamic simulation. We examine a number of factors potentially affecting supermassive black hole growth at high redshift in cosmological simulations. We find insignificant differences in the black hole accretion history by (i) varying the region over which feedback energy is deposited directly, (ii) changing mass resolution by factors of up to 64, (iii) changing the black hole seed mass by a factor of 100. Switching from the density-entropy formulation to the pressure-entropy formulation of smoothed particle hydrodynamics slightly increases the accretion rate. In general numerical details/model parameters appear to have small effects on the main fuelling mechanism for black holes at these high redshifts. The insensitivity to simulation technique seems to be a hallmark of the cold flow feeding picture of these high-z supermassive black holes. We show that the gas that participates in critical accretion phases in these massive objects at z > 6-7 is in all cases colder, denser and forms more coherent streams than the average gas in the halo. This is also mostly the case when the black hole accretion is feedback regulated (z < 6), however, the distinction is less prominent. For our resimulated haloes, cold flows appear to be a viable mechanism for forming the most massive black holes in the early universe, occurring naturally in Λ cold dark matter models of structure formation, without requiring fine-tuning of numerical parameters.

  14. Compressive high speed flow microscopy with motion contrast (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Bosworth, Bryan; Stroud, Jasper R.; Tran, Dung N.; Tran, Trac D.; Chin, Sang; Foster, Mark A.

    2016-03-01

    High-speed continuous imaging systems are constrained by analog-to-digital conversion, storage, and transmission. However, real video signals of objects such as microscopic cells and particles require only a few percent or less of the full video bandwidth for high fidelity representation by modern compression algorithms. Compressed Sensing (CS) is a recent influential paradigm in signal processing that builds real-time compression into the acquisition step by computing inner products between the signal of interest and known random waveforms and then applying a nonlinear reconstruction algorithm. Here, we extend the continuous high-rate photonically-enabled compressed sensing (CHiRP-CS) framework to acquire motion contrast video of microscopic flowing objects. We employ chirp processing in optical fiber and high-speed electro-optic modulation to produce ultrashort pulses each with a unique pseudorandom binary sequence (PRBS) spectral pattern with 325 features per pulse at the full laser repetition rate (90 MHz). These PRBS-patterned pulses serve as random structured illumination inside a one-dimensional (1D) spatial disperser. By multiplexing the PRBS patterns with a user-defined repetition period, the difference signal y_i=&phi_i (x_i - x_{i-tau}) can be computed optically with balanced detection, where x is the image signal, phi_i is the PRBS pattern, and tau is the repetition period of the patterns. Two-dimensional (2D) image reconstruction via iterative alternating minimization to find the best locally-sparse representation yields an image of the edges in the flow direction, corresponding to the spatial and temporal 1D derivative. This provides both a favorable representation for image segmentation and a sparser representation for many objects that can improve image compression.

  15. High risk human papillomavirus type 16 and 18 infection in the cervical lesions of women with epithelial cell abnormality in Pap smear: A cytohistomorphologic association in Bangladeshi women

    PubMed Central

    Banik, Urmila; Ahamad, M. Shahab Uddin; Bhattacharjee, Pradip; Adhikary, Arun Kumar; Rahman, Zillur

    2013-01-01

    Background: The aim of this study was to find out the extent of high-risk human papillomavirus (hrHPV) type 16/18 infection in the cervical tissue of women with epithelial cell abnormality in Pap smear and to establish an association between hrHPV type 16/18 infection and cytohistomorphology. Materials and Methods: A cross-sectional descriptive study was carried out in 1699 patients who went through Pap smear examination. Prevalence of epithelial cell abnormality was calculated. Forty eight of these women underwent routine histopathology and 47 were evaluated for human papillomavirus (HPV) type 16/18 by polymerase chain reaction assay. Results: Total 139 women revealed epithelial cell abnormality. Histopathology showed simple inflammation to malignancy. HPV type 16/18 infection was detected in 40.42% (19/47) of the patients. Individually type 16 and 18 were positive in 7 (14.9%) cases each and dual infection with type 16 and 18 were seen in 5 (10.6%) cases. While cervical intraepithelial neoplasia grade 1 (CIN 1) and < CIN 1 lesions showed 18.75% (3 out of 16) and 35% (7 out of 20) positivity respectively, ≥CIN 2 lesions revealed positivity of 81.82% (9 out of 11). Eighty percent HPV 16/18 positivity was seen in women of < 30 years of age. Conclusion: The findings of this study will contribute to HPV 16/18 knowledge in Bangladesh that will be useful in assessing the success of current vaccines with limited type spectra and augmenting cervical cancer screening strategies. PMID:23976895

  16. Decreased HCN2 expression in STN contributes to abnormal high-voltage spindles in the cortex and globus pallidus of freely moving rats.

    PubMed

    Yang, Chen; Zhang, Jia-Rui; Chen, Lei; Ge, Shun-Nan; Wang, Ju-Lei; Yan, Zhi-Qiang; Jia, Dong; Zhu, Jun-Ling; Gao, Guo-Dong

    2015-08-27

    Abnormal oscillation in the cortical-basal ganglia loop is involved in the pathophysiology of parkinsonism. High-voltage spindles (HVSs), one of the main type abnormal oscillations in Parkinson's disease, are regulated by dopamine D2-like receptors but not D1-like receptors. However, little is known about how dopamine D2-like receptors regulate HVSs and the role of hyperpolarization-activated cyclic nucleotide-gated2 (HCN2) in HVSs regulation. We simultaneously recorded the local field potential (LFP) in globus pallidus (GP) and electrocorticogram (ECoG) in primary motor cortex (M1) in freely moving 6-hydroxydopamine (6-OHDA) lesioned or control rats. The expression of HCN2 and dopamine D2 receptor in the subthalamic nucleus (STN) was examined by immunochemical staining and Western blotting. We also tested the role of HCN2 in HVSs regulation by using pharmacological and shRNA methodology. We found that dopamine D2-like receptor agonists suppressed the increased HVSs in 6-OHDA lesioned rats. HCN2 was co-expressed with dopamine D2 receptor in the STN, and dopamine depletion decreased the expression of HCN2 as well as dopamine D2 receptor which contribute to the regulation of HVSs. HCN2 was down regulated by HCN2 shRNA, which thereby led to an increase in the HVSs in naïve rats while HCN2 agonist reduced the HVSs in 6-OHDA lesioned rats. These results suggest that HCN2 in the STN is involved in abnormal oscillation regulation between M1 cortex and GP.

  17. Flow cytometry

    NASA Astrophysics Data System (ADS)

    Steinkamp, John A.

    1984-09-01

    Flow cytometry instrumentation developed from early efforts to count cells and particles in liquid suspension as they passed through a sensing device. Since the mid-1960's sophisticated instruments have been designed for analyzing cells based on various cytological, biochemical, and functional properties. These instruments have revolutionized automated cell analysis methods in that measurements are made at high speed, multiparameter data is correlated on each cell, statistical precision is high, and cells are separated in high purity from heterogeneous mixtures for identification and functional analysis. Advanced instruments capable of measuring cell volume, surface area, multicolor fluorescence, fluorescence polarization, light scatter within various angular regions, and axial light loss (extinction) at different wavelengths are being used in biomedical research for analyzing and sorting normal and abnormal cell populations. This article reviews the development of flow cytometers, the conceptual basis of flow measurements, and discusses some of the numerous applications of the technology in biology and medicine.

  18. High throughput analysis of samples in flowing liquid

    DOEpatents

    Ambrose, W. Patrick; Grace, W. Kevin; Goodwin, Peter M.; Jett, James H.; Orden, Alan Van; Keller, Richard A.

    2001-01-01

    Apparatus and method enable imaging multiple fluorescent sample particles in a single flow channel. A flow channel defines a flow direction for samples in a flow stream and has a viewing plane perpendicular to the flow direction. A laser beam is formed as a ribbon having a width effective to cover the viewing plane. Imaging optics are arranged to view the viewing plane to form an image of the fluorescent sample particles in the flow stream, and a camera records the image formed by the imaging optics.

  19. Modeling the pharyngeal pressure during adult nasal high flow therapy.

    PubMed

    Kumar, Haribalan; Spence, Callum J T; Tawhai, Merryn H

    2015-12-01

    Subjects receiving nasal high flow (NHF) via wide-bore nasal cannula may experience different levels of positive pressure depending on the individual response to NHF. In this study, airflow in the nasal airway during NHF-assisted breathing is simulated and nasopharyngeal airway pressure numerically computed, to determine whether the relationship between NHF and pressure can be described by a simple equation. Two geometric models are used for analysis. In the first, 3D airway geometry is reconstructed from computed tomography images of an adult nasal airway. For the second, a simplified geometric model is derived that has the same cross-sectional area as the complex model, but is more readily amenable to analysis. Peak airway pressure is correlated as a function of nasal valve area, nostril area and cannula flow rate, for NHF rates of 20, 40 and 60 L/min. Results show that airway pressure is related by a power law to NHF rate, valve area, and nostril area.

  20. High heat flux burnout in subcooled flow boiling

    NASA Astrophysics Data System (ADS)

    Celata, G. P.; Cumo, M.; Mariani, A.

    1995-09-01

    The paper reports the results of an experimental research carried out at the Heat Transfer Division of the Energy Department, C.R. Casaccia, on the thermal hydraulic characterization of subcooled flow boiling CHF under typical conditions of thermonuclear fusion reactors, i.e. high liquid velocity and subcooling. The experiment was carried out exploring the following parameters: channel diameter (from 2.5 to 8.0 mm), heated length (10 and 15 cm), liquid velocity (from 2 to 40 m/s), exit pressure (from atmospheric to 5.0 MPa), inlet temperature (from 30 to 80 °C), channel orientation (vertical and horizontal). A maximum CHF value of 60.6 MW/m2 has been obtained under the following conditions: T in=30°, p=2.5 MPa, u=40 m/s, D=2.5 mm (smooth channel) Turbulence promoters (helically coiled wires) have been employed to further enhance the CHF attainable with subcooled flow boiling. Helically coiled wires allow an increase of 50% of the maximum CHF obtained with smooth channels.

  1. Efficient simulation of detached flows at high Reynolds number

    NASA Astrophysics Data System (ADS)

    Vega, Jose M.; Asensio, Victor; Herrero, Raul; Varas, Fernando

    2014-11-01

    A method is presented for the computationally efficient simulation of quasi-periodic detached flows in multi-parameter problems at very large Reynolds numbers, keeping in mind a variety of applications, including helicopter flight simulators, control and certification of unmanned aerial vehicles, control of wind turbines, conceptual design in aeronautics, and civil aerodynamics. In many of these applications, the large scale flows (ignoring the smaller turbulent scales) are at most quasi-periodic, namely the Fourier transform exhibits a finite set of concentrated peaks resulting from the nonlinear passive interaction of periodic wakes. The method consists in an offline preprocess and the online operation. In the preprocess, a standard CFD solver (such as URANS) is used in combination with several ingredients such as an iterative combination proper orthogonal decomposition and fast Fourier transform. The online operation is made with a combination of high order singular value decomposition and interpolation. The performance of the method is tested considering the ow over a fairly complex urban topography, for various free stream intensities and orientations, seeking real time online simulations.

  2. Experimental Analysis of Flow over a Highly Maneuverable Airframe

    NASA Astrophysics Data System (ADS)

    Spirnak, Jonathan; Benson, Michael; van Poppel, Bret; Elkins, Christopher; Eaton, John; Team HMA Team

    2015-11-01

    One way to reduce the collateral damage in war is by increasing the accuracy of indirect fire weapons. The Army Research Laboratory is currently developing a Highly Maneuverable Airframe (HMA) consisting of four deflecting canards to provide in-flight maneuverability while fins maintain short duration aerodynamic stability. An experiment was conducted using Magnetic Resonance Velocimetry (MRV) techniques to gather three dimensional, three-component velocity data for fluid flow over a scaled down HMA model. Tests were performed at an angle of attack of 2.3° and canard deflection angles of 0° and 2°. The resulting data serve to both validate computational fluid dynamics (CFD) simulations and understand the flow over this complex geometry. Particular interest is given to the development of the tip and inboard vortices that originate at the canard/body junction and the canard tips to determine their effects on airframe stability. Results show the development of a strong tip vortex and four weaker inboard vortices off each canard. Although the weaker inboard vortices dissipate rapidly downstream of the canard trailing edges, the stronger tip vortices persist until reaching the fins approximately six chord lengths downstream of the canard trailing edges. Team HMA designed and built the water channel and airframe for this experiment.

  3. Cytogenetic abnormalities in multiple myeloma: poor prognosis linked to concomitant detection in random and focal lesion bone marrow samples and associated with high-risk gene expression profile.

    PubMed

    Zhou, Yiming; Nair, Bijay; Shaughnessy, John D; Cartron, Marie-Astrid; Haessler, Jeff; Anaissie, Elias; van Rhee, Frits; Crowley, John; Barlogie, Bart

    2009-06-01

    The clinical significance of cytogenetic abnormalities (CA) present in randomly sampled (RS) or focal lesion (FL) bone marrow sites was examined in 419 untreated myeloma patients. Among 290 patients with gene expression profiling (GEP) data generated from RS sites, GEP-defined high-risk was present in 52% of the RS+/FL+ group but in only 9% of the remainder (P < 0.001). The RS+/FL+ constellation (18%) was an independent predictor of poor survival, also after adjusting for GEP-derived risk and TP53 status (Hazard ratio = 2.42, P = 0.004). The prevalence of high-risk myeloma in the RS+/FL+ group may reflect a dissemination-prone condition not shared by the other three groups. PMID:19344415

  4. High flow nasal cannula in children: a literature review.

    PubMed

    Mikalsen, Ingvild Bruun; Davis, Peter; Øymar, Knut

    2016-01-01

    High flow nasal cannula (HFNC) is a relatively new non-invasive ventilation therapy that seems to be well tolerated in children. Recently a marked increase in the use of HFNC has been seen both in paediatric and adult care settings. The aim of this study was to review the current knowledge of HFNC regarding mechanisms of action, safety, clinical effects and tolerance in children beyond the newborn period.We performed a systematic search of the databases PubMed, Medline, EMBASE and Cochrane up to 12th of May 2016. Twenty-six clinical studies including children on HFNC beyond the newborn period with various respiratory diseases hospitalised in an emergency department, paediatric intensive care unit or general ward were included. Five of these studies were interventional studies and 21 were observational studies. Thirteen studies included only children with bronchiolitis, while the other studies included children with various respiratory conditions. Studies including infants hospitalised in a neonatal ward, or adults over 18 years of age, as well as expert reviews, were not systematically evaluated, but discussed if appropriate.The available studies suggest that HFNC is a relatively safe, well-tolerated and feasible method for delivering oxygen to children with few adverse events having been reported. Different mechanisms including washout of nasopharyngeal dead space, increased pulmonary compliance and some degree of distending airway pressure may be responsible for the effect. A positive clinical effect on various respiratory parameters has been observed and studies suggest that HFNC may reduce the work of breathing. Studies including children beyond the newborn period have found that HFNC may reduce the need of continuous positive airway pressure (CPAP) and invasive ventilation, but these studies are observational and have a low level of evidence. There are no international guidelines regarding flow rates and the optimal maximal flow for HFNC is not known, but few

  5. High-Resolution Flow Logging for Hydraulic Characterization of Boreholes and Aquifer Flow Zones at Contaminated Bedrock Sites

    NASA Astrophysics Data System (ADS)

    Williams, J. H.; Johnson, C. D.; Paillet, F. L.

    2004-05-01

    In the past, flow logging was largely restricted to the application of spinner flowmeters to determine flow-zone contributions in large-diameter production wells screened in highly transmissive aquifers. Development and refinement of tool-measurement technology, field methods, and analysis techniques has greatly extended and enhanced flow logging to include the hydraulic characterization of boreholes and aquifer flow zones at contaminated bedrock sites. State-of-the-art in flow logging will be reviewed, and its application to bedrock-contamination investigations will be presented. In open bedrock boreholes, vertical flows are measured with high-resolution flowmeters equipped with flexible rubber-disk diverters fitted to the nominal borehole diameters to concentrate flow through the measurement throat of the tools. Heat-pulse flowmeters measure flows in the range of 0.05 to 5 liters per minute, and electromagnetic flowmeters measure flows in the range of 0.3 to 30 liters per minute. Under ambient and low-rate stressed (either extraction or injection) conditions, stationary flowmeter measurements are collected in competent sections of the borehole between fracture zones identified on borehole-wall images. Continuous flow, fluid-resistivity, and temperature logs are collected under both sets of conditions while trolling with a combination electromagnetic flowmeter and fluid tool. Electromagnetic flowmeters are used with underfit diverters to measure flow rates greater than 30 liters per minute and suppress effects of diameter variations while trolling. A series of corrections are applied to the flow-log data to account for the zero-flow response, bypass, trolling, and borehole-diameter biases and effects. The flow logs are quantitatively analyzed by matching simulated flows computed with a numerical model to measured flows by varying the hydraulic properties (transmissivity and hydraulic head) of the flow zones. Several case studies will be presented that demonstrate

  6. High frequency of rare structural chromosome abnormalities at relapse of cytogenetically normal acute myeloid leukemia with FLT3 internal tandem duplication.

    PubMed

    Gourdin, Theodore S; Zou, Ying; Ning, Yi; Emadi, Ashkan; Duong, Vu H; Tidwell, Michael L; Chen, Ching; Rassool, Feyruz V; Baer, Maria R

    2014-01-01

    FLT3 internal tandem duplication (ITD) mutations are present in acute myeloid leukemia (AML) in 30% of patients with acute myeloid leukemia (AML), most commonly in those with a normal karyotype, and are associated with short relapse-free survival. Both in vitro and in vivo studies of FLT3-ITD cell lines have demonstrated reactive oxygen species-mediated DNA double-strand breaks and associated error-prone DNA repair as a mechanism of genomic instability, and we hypothesized that genomic instability might be manifested by cytogenetic changes at relapse of FLT3-ITD AML. We retrospectively reviewed charts of patients with cytogenetically normal (CN) FLT3-ITD AML treated at the University of Maryland Greenebaum Cancer Center, with attention to metaphase analysis results at relapse. Cytogenetic data were available from first and, when applicable, subsequent relapses for 15 patients diagnosed with CN FLT3-ITD AML. Among 12 patients with documented FLT3-ITD at first and, when applicable, subsequent relapse, 10 had cytogenetic changes, including nine with rare structural abnormalities. The high frequency of rare structural chromosome abnormalities at relapse in our case series supports a role of genomic instability in the genesis of relapse, and suggests that reactive oxygen species-generating and DNA repair pathways might be therapeutic targets in FLT3-ITD AML. PMID:25441683

  7. Seed particle response and size characterization in high speed flows

    NASA Technical Reports Server (NTRS)

    Rudoff, Roger C.; Bachalo, William D.

    1991-01-01

    The response of seed particles ranging between 0.7 and 8.7 micron is determined using a phase Doppler particle analyzer which simultaneously measures particle size and velocity. The stagnant seed particles are entrained into a high speed free jet at velocities ranging from 40 to 300 m/s. The size-mean axial velocity correlation and size-rms velocity correlations are used to determine the particle response to the sudden acceleration. It was determined that at the lower speeds, seed particles up to approximately 5 microns are adequate, but as velocities approach 300 m/s only particles on the order of one micron are suitable. The ability to determine size and velocity simultaneously is essential if seeding with polydispersions is used since it allows the rejection of data which will not accurately represent the flow field.

  8. Uncertainty quantification for flow in highly heterogeneous porous media

    SciTech Connect

    Tartakovsky, D. M.; Xiu, D.

    2004-01-01

    Natural porous media are highly heterogeneous and characterized by parameters that are often uncertain due to the lack of sufficient data. This uncertainty (randomness) occurs on a multiplicity of scales. We focus on geologic formations with the two dominant scales of uncertainty: a large-scale uncertainty in the spatial arrangement of geologic facies and a small-scale uncertainty in the parameters within each facies. We propose an approach that combines random domain decompositions (RDD) and polynomial chaos expansions (PCE) to account for the large- and small-scales of uncertainty, respectively. We present a general framework and use a one-dimensional flow example to demonstrate that our combined approach provides robust, non-perturbative approximations for the statistics of the system states.

  9. Nonequilibrium viscous flow over Jovian entry probes at high altitudes

    NASA Technical Reports Server (NTRS)

    Kumar, A.; Szema, K. Y.; Tiwari, S. N.

    1979-01-01

    The viscous chemical nonequilibrium flow around a Jovian entry body is investigated at high altitudes using two different methods. First method is only for the stagnation region and integrates the full Navier-Stokes equations from the body surface to the freestream. The second method uses viscous shock layer equations between the body surface and the shock. Due to low Reynolds numbers, both methods use surface slip boundary conditions and the second method also uses shock slip boundary conditions. The results of the two methods are compared at the stagnation point. It is found that the entire shock layer is under chemical nonequilibrium at higher altitudes and that the slip boundary conditions are important at these altitudes.

  10. Heat flux measurement in a high enthalpy plasma flow

    NASA Astrophysics Data System (ADS)

    Löhle, Stefan; Battaglia, Jean-Luc; Gardarein, Jean-Laurent; Jullien, Pierre; van Ootegem, Bruno

    2008-11-01

    It is a widely used approach to measure heat flux in harsh environments like high enthalpy plasma flows, fusion plasma and rocket motor combustion chambers based on solving the inverse heat conduction problem in a semi-infinite environment. This approach strongly depends on model parameters and geometrical aspects of the sensor design. In this work the surface heat flux is determined by solving the inverse heat conduction problem using an identified system as a direct model. The identification of the system is performed using calibration measurements with modern laser technique and advanced data handling. The results of the identified thermo-physical system show that a non-integer model appears most adapted to this particular problem. It is concluded that the new method improves the heat flux sensor significantly and furthermore extend its application to very short measurement times.

  11. Flow of High Internal Phase Ratio Emulsions through Pipes

    NASA Astrophysics Data System (ADS)

    Kostak, K.; Özsaygı, R.; Gündüz, I.; Yorgancıoǧlu, E.; Tekden, E.; Güzel, O.; Sadıklar, D.; Peker, S.; Helvacı, Ş. Ş.

    2015-04-01

    The flow behavior of W/O type of HIPRE stabilized by hydrogen bonds with a sugar (sorbitol) in the aqueous phase, was studied. Two groups of experiments were done in this work: The effect of wall shear stresses were investigated in flow through pipes of different diameters. For this end, HIPREs prestirred at constant rate for the same duration were used to obtain similar drop size distributions. Existence and extent of elongational viscosity were used as a probe to elucidate the effect of drop size distribution on the flow behavior: HIPREs prestirred for the same duration at different rates were subjected to flow through converging pipes. The experimental flow curves for flow through small cylindrical pipes indicated four different stages: 1) initial increase in the flow rate at low pressure difference, 2) subsequent decrease in the flow rate due to capillary flow, 3) pressure increase after reaching the minimum flow rate and 4) slip flow after a critical pressure difference. HIPREs with sufficient external liquid phase in the plateau borders can elongate during passage through converging pipes. In the absence of liquid stored in the plateau borders, the drops rupture during extension and slip flow takes place without elongation.

  12. High speed magnetized flows in the quiet Sun

    NASA Astrophysics Data System (ADS)

    Quintero Noda, C.; Borrero, J. M.; Orozco Suárez, D.; Ruiz Cobo, B.

    2014-09-01

    Context. We analyzed spectropolarimetric data recorded with Hinode/SP in quiet-Sun regions located at the disk center. We found single-lobed Stokes V profiles showing highly blue- and red-shifted signals. Oftentimes both types of events appear to be related to each other. Aims: We aim to set constraints on the nature and physical causes of these highly Doppler-shifted signals, as well as to study their spatial distribution, spectropolarimetric properties, size, and rate of occurrence. Also, we plan to retrieve the variation of the physical parameters with optical depth through the photosphere. Methods: We have examined the spatial and polarimetric properties of these events using a variety of data from the Hinode spacecraft. We have also inferred the atmospheric stratification of the physical parameters by means of the inversion of the observed Stokes profiles employing the Stokes Inversion based on Response functions (SIR) code. Finally, we analyzed their evolution using a time series from the same instrument. Results: Blue-shifted events tend to appear over bright regions at the edge of granules, while red-shifted events are seen predominantly over dark regions on intergranular lanes. Large linear polarization signals can be seen in the region that connects them. The magnetic structure inferred from the time series revealed that the structure corresponds to a Ω-loop, with one footpoint always over the edge of a granule and the other inside an intergranular lane. The physical parameters obtained from the inversions of the observed Stokes profiles in both events show an increase with respect to the Harvard-Smithonian reference atmosphere in the temperature at log τ500 ∈ (-1, -3) and a strong magnetic field, B ≥ 1 kG, at the bottom of the atmosphere that quickly decreases upward until vanishing at log τ500 ≈ -2. In the blue-shifted events, the LOS velocities change from upflows at the bottom to downflows at the top of the atmosphere. Red-shifted events

  13. Transmissivity and head covariances for flow in highly heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Dagan, G.; Fiori, A.; Janković, I.

    2004-07-01

    Spatially variable transmissivity T of aquifers is modeled as random. Analysis of field data [Water Resour. Res. 21 (1985) 563] indicate that the logtransmissivity Y= ln T is normal and its covariance can be characterized by three parameters: the variance σYc2 and the integral scale IY of correlated residuals and a nugget σYn2, representing variability of small support. The equation of flow is stochastic and the head H is also random. The head-logtransmissivity cross-covariance CHY and the head variogram ΓH can be used conveniently to solve the direct and inverse problems. These covariances are derived for an unbounded domain and for mean uniform flow of constant head gradient - J. Under these conditions, analytical expressions were determined in the past by first-order approximation in σYc2, pertinent to weak heterogeneity. The aim of the present study is to derive CHY and ΓH for highly heterogeneous aquifers of total variance σY2≤4. This goal is achieved by adopting a multi-indicator model of the aquifer consisting of circular inclusions of radius R and of normal logtransmissivity of variance σY2, submerged in a matrix of effective transmissivity TG (geometric mean). The system is characterized by σY2, the integral scale IY=8 R/(3π) and the volume fraction of inclusions n, which are simply related to the aquifer parameters σYc2, σYn2 and IY. The flow problem is solved numerically at high accuracy by the analytic element method. The medium is modeled by 50,000 inclusions and parameters values are σY2=0.1, 1, 2, 4 and n=0.4, 0.65, 0.9. Analytical solutions are derived by the effective medium approximation (EMA), in which each inclusion is regarded as submerged in a medium of effective transmissivity, and by first-order approximation (FAO in σY2). Comparison between the numerical and analytical solutions shows that CYH is overestimated by FOA and is in agreement with the EMA. The head variogram is in agreement with EMA for n≤0.65, but underestimated

  14. High energy sodium based room temperature flow batteries

    NASA Astrophysics Data System (ADS)

    Shamie, Jack

    As novel energy sources such as solar, wind and tidal energies are explored it becomes necessary to build energy storage facilities to load level the intermittent nature of these energy sources. Energy storage is achieved by converting electrical energy into another form of energy. Batteries have many properties that are attractive for energy storage including high energy and power. Among many different types of batteries, redox flow batteries (RFBs) offer many advantages. Unlike conventional batteries, RFBs store energy in a liquid medium rather than solid active materials. This method of storage allows for the separation of energy and power unlike conventional batteries. Additionally flow batteries may have long lifetimes because there is no expansion or contraction of electrodes. A major disadvantage of RFB's is its lower energy density when compared to traditional batteries. In this Thesis, a novel hybrid Na-based redox flow battery (HNFB) is explored, which utilizes a room temperature molten sodium based anode, a sodium ion conducting solid electrolyte and liquid catholytes. The sodium electrode leads to high voltages and energy and allows for the possibility of multi-electron transfer per molecule. Vanadium acetylacetonate (acac) and TEMPO have been investigated for their use as catholytes. In the vanadium system, 2 electrons transfers per vanadium atom were found leading to a doubling of capacity. In addition, degradation of the charged state was found to be reversible within the voltage range of the cell. Contamination by water leads to the formation of vanadyl acetylacetonate. Although it is believed that vanadyl complex need to be taken to low voltages to be reduced back to vanadium acac, a new mechanism is shown that begins at higher voltages (2.1V). Vanadyl complexes react with excess ligand and protons to reform the vanadium complex. During this reaction, water is reformed leading to the continuous cycle in which vanadyl is formed and then reduced back

  15. Solid rocket booster internal flow analysis by highly accurate adaptive computational methods

    NASA Technical Reports Server (NTRS)

    Huang, C. Y.; Tworzydlo, W.; Oden, J. T.; Bass, J. M.; Cullen, C.; Vadaketh, S.

    1991-01-01

    The primary objective of this project was to develop an adaptive finite element flow solver for simulating internal flows in the solid rocket booster. Described here is a unique flow simulator code for analyzing highly complex flow phenomena in the solid rocket booster. New methodologies and features incorporated into this analysis tool are described.

  16. Action plan for responses to abnormal conditions in Hanford Site radioactive waste tanks with high organic content. Revision 1

    SciTech Connect

    Fowler, K.D.

    1993-07-01

    This action plan describes the criteria and the organizational responsibilities required for ensuring that waste storage tanks with high organic contents are maintained in a safe condition at the Hanford Site. In addition, response actions are outlined for (1) prevention or mitigation of excessive temperatures; or (2) a material release from any waste tank with high organic content. Other response actions may be defined by Westinghouse Hanford Company Systems Engineering if a waste tank parameter goes out of specification. Trend analysis indicates the waste tank parameters have seasonal variations, but are otherwise stable.

  17. Low flow and high flow responses to converting natural grassland into bluegum ( Eucalyptus globulus) in Nilgiris watersheds of South India

    NASA Astrophysics Data System (ADS)

    Sikka, A. K.; Samra, J. S.; Sharda, V. N.; Samraj, P.; Lakshmanan, V.

    2003-01-01

    A concern has been raised in many parts of the world over the effect of large scale planting of Eucalyptus on hydrological behaviour of small watersheds. Hydrological response of watersheds due to conversion of natural grasslands into bluegum ( Eucalyptus globulus) plantations on low flows and high flows has been presented in this paper. The concept of using low flow index (LFI) as a tool to study and quantify the effects of bluegum plantation on low flow regime has been demonstrated. Conversion of natural grasslands into bluegum plantations has resulted in decreased low flow volume as well as peak flow, which in turn increased the soil moisture losses. These effects were more pronounced during the second rotation (i.e. first coppiced growth) as compared to the first rotation. Significant reduction in low flow as a result of decline in base flow could be predicted with LFI decreasing by 2.0 and 3.75 times, in the first and second rotation, respectively. Moderation in peak discharge rates was also observed as a result of bluegum plantation. Probability plots of peak discharge tend to suggest that the effect of bluegum plantation on peak flows become insignificant for the floods with higher return periods. These results clearly suggest that caution need to be exercised while planning large scale conversion of natural grasslands into bluegum plantations in the catchments of hydro-electric reservoirs in the Nilgiris which adversely affects water availability especially during lean flow period.

  18. Abnormal Functional Specialization within Medial Prefrontal Cortex in High-Functioning Autism: A Multi-Voxel Similarity Analysis

    ERIC Educational Resources Information Center

    Gilbert, Sam J.; Meuwese, Julia D. I.; Towgood, Karren J.; Frith, Christopher D.; Burgess, Paul W.

    2009-01-01

    Multi-voxel pattern analyses have proved successful in "decoding" mental states from fMRI data, but have not been used to examine brain differences associated with atypical populations. We investigated a group of 16 (14 males) high-functioning participants with autism spectrum disorder (ASD) and 16 non-autistic control participants (12 males)…

  19. Normalisation of a severely abnormal ductus venosus Doppler flow velocity waveform in a growth-retarded fetus with absent end-diastolic flow in the umbilical artery and congenital anomalies.

    PubMed

    Müller, T; Rehn, M; Girschick, G; Kristen, P; Dietl, J

    2001-01-01

    Doppler recordings of fetal venous blood flow seem to be superior to arterial velocimetry and CTG concerning the prediction of fetal outcome and optimal time of delivery in pregnancies with fetal growth retardation and AREDV. An improvement of arterial Doppler flow velocities has been described. We report the reappearance of a normal end-diastolic flow velocity in a ductus venosus temporarily showing reversed end-diastolic flow in a growth-retarded fetus with congenital anomalies. This normalization was accompanied by an improvement of the CTG, a loss of umbilical vein pulsations, a reappearance of umbilical diastolic flow and a progressive return of cerebral and venous blood flow into the 'normal' range. Improvement of fetal condition may be the explanation for our observation.

  20. Prevalence of High-Risk Human Papillomavirus (HR-HPV) Genotypes and Multiple Infections in Cervical Abnormalities from Northern Xinjiang, China

    PubMed Central

    Du, Jingyun; Jiang, Jianjun; Jia, Xuesong; Chen, Chuangfu; Wang, Yuanzhi

    2016-01-01

    Multiple human papillomavirus (HPV) genotypes often coexist within the cervical epithelia and are frequently detected together in various grades of the cervical neoplasia. To date, only a few reports exist on multiple HPV infections of HPV in Xinjiang Uygur Autonomous Region (XUAR). In the present study, we investigated the prevalence of High-Risk HPV (HR-HPV) genotypes and multiple infections. Cervical cytology samples were collected from 428 women who presented cervical abnormalities. Genotyping of HPV was performed by polymerase chain reaction–sequencing based typing (PCR-SBT) using consensus primers and specific primers. Of them, 166 samples were positive for HPV according to PCR results using the consensus primers. These samples contained cervical abnormalities enriched with inflammation (n = 107), cervical intraepithelial neoplasia (CIN) I (n = 19), CINII-III (n = 9) and cervical cancer (n = 31). Of the 166 HPV positive samples as determined by PCR analysis, 151 were further typed by PCR-SBT using 19 pairs of genotype-specific primers. Using this method, 17 different HR-HPV genotypes were identified. The most frequently observed HPV genotypes were HPV16 (44.0%, 73/166), 53 (28.9%, 48/166), 52 (25.3%, 42/166), 58 (22.3%, 37/166) and 35 (17.5%, 29/166). The proportions of single and multiple infections in the HPV-positive specimens were 34.9% and 65.1%, respectively. Multiple HPV types were most prevalent in the inflammatory state (63.0%), followed by cervical cancer (24.1%), CINI (11.1%), and CINII-III (1.9%). The results of our data analyses suggested that i) multiple HPV infection is not necessarily correlated with the severity of cervical abnormalities; and ii) among the multiple HPV infections, double infections combined with HPV16 is the most common. In addition, L1 full-length sequences of the top five high-risk HPV genotypes were amplified and sequenced. According to the L1 sequence of the epidemic genotypes that were amplified, we found that these

  1. Vescalagin from Pink Wax Apple [Syzygium samarangense (Blume) Merrill and Perry] Alleviates Hepatic Insulin Resistance and Ameliorates Glycemic Metabolism Abnormality in Rats Fed a High-Fructose Diet.

    PubMed

    Huang, Da-Wei; Chang, Wen-Chang; Wu, James Swi-Bea; Shih, Rui-Wen; Shen, Szu-Chuan

    2016-02-10

    This study investigates the ameliorative effect of vescalagin (VES) isolated from Pink wax apple fruit on hepatic insulin resistance and abnormal carbohydrate metabolism in high-fructose diet (HFD)-induced hyperglycemic rats. The results show that in HFD rats, VES significantly reduced the values of the area under the curve for glucose in an oral glucose tolerance test and the homeostasis model assessment of insulin resistance index. VES significantly enhanced the activity of hepatic antioxidant enzymes while reducing thiobarbituric acid-reactive substances in HFD rats. Western blot assay revealed that VES reduced hepatic protein expression involved in inflammation pathways while up-regulating expression of hepatic insulin signaling-related proteins. Moreover, VES up-regulated the expression of hepatic glycogen synthase and hepatic glycolysis-related proteins while down-regulating hepatic gluconeogenesis-related proteins in HFD rats. This study suggests some therapeutic potential of VES in preventing the progression of diabetes mellitus. PMID:26800576

  2. Vescalagin from Pink Wax Apple [Syzygium samarangense (Blume) Merrill and Perry] Alleviates Hepatic Insulin Resistance and Ameliorates Glycemic Metabolism Abnormality in Rats Fed a High-Fructose Diet.

    PubMed

    Huang, Da-Wei; Chang, Wen-Chang; Wu, James Swi-Bea; Shih, Rui-Wen; Shen, Szu-Chuan

    2016-02-10

    This study investigates the ameliorative effect of vescalagin (VES) isolated from Pink wax apple fruit on hepatic insulin resistance and abnormal carbohydrate metabolism in high-fructose diet (HFD)-induced hyperglycemic rats. The results show that in HFD rats, VES significantly reduced the values of the area under the curve for glucose in an oral glucose tolerance test and the homeostasis model assessment of insulin resistance index. VES significantly enhanced the activity of hepatic antioxidant enzymes while reducing thiobarbituric acid-reactive substances in HFD rats. Western blot assay revealed that VES reduced hepatic protein expression involved in inflammation pathways while up-regulating expression of hepatic insulin signaling-related proteins. Moreover, VES up-regulated the expression of hepatic glycogen synthase and hepatic glycolysis-related proteins while down-regulating hepatic gluconeogenesis-related proteins in HFD rats. This study suggests some therapeutic potential of VES in preventing the progression of diabetes mellitus.

  3. Characteristics of high gradient insulators for accelerator and high power flow applications

    SciTech Connect

    Elizondo, J.M.; Krogh, M.L.; Smith, D.

    1997-07-01

    The high gradient insulator has been demonstrated to operate at levels comparable or better than special geometry or coated insulators. Some patented insulator configurations allow for sophisticated accelerator structures, high power flow interfaces, and microwave applications not previously possible. Sophisticated manufacturing techniques available at AlliedSignal FM and T made this development possible. Bipolar and high power flow applications are specially suited for present insulator designs. The insulator shows a beneficial effect when used under RF fields or RF structures. These insulators can be designed, to a first approximation, from simple electron flight path equations. With a recently developed model of surface flashover physics the authors completed a set of design calculations that include effects such as layer density and dielectric/metal thickness. Experimental data, obtained in the last few years of development, is presented and reviewed. Several insulator fabrication characteristics, indicating critical design parameters, are also presented.

  4. A Rare Stapes Abnormality

    PubMed Central

    Kanona, Hala; Virk, Jagdeep Singh; Kumar, Gaurav; Chawda, Sanjiv; Khalil, Sherif

    2015-01-01

    The aim of this study is to increase awareness of rare presentations, diagnostic difficulties alongside management of conductive hearing loss and ossicular abnormalities. We report the case of a 13-year-old female reporting progressive left-sided hearing loss and high resolution computed tomography was initially reported as normal. Exploratory tympanotomy revealed an absent stapedius tendon and lack of connection between the stapes superstructure and footplate. The footplate was fixed. Stapedotomy and stapes prosthesis insertion resulted in closure of the air-bone gap by 50 dB. A review of world literature was performed using MedLine. Middle ear ossicular discontinuity can result in significant conductive hearing loss. This can be managed effectively with surgery to help restore hearing. However, some patients may not be suitable or decline surgical intervention and can be managed safely conservatively. PMID:25628909

  5. Salivary abnormalities in Prader-Willi Syndrome

    SciTech Connect

    Hart, S.; Poshva, C.

    1994-09-01

    Although abnormal saliva is a well documented finding in PWS, little is known about the saliva in these individuals. We have recently undertaken a study to characterize the salivary composition from PW patients and to see if there is any correlation with their underlying molecular diagnosis (deletion vs. disomy). We have collected whole saliva on 3 patients; 2 had normal high-resolution karyotype analysis (Cases 1 & 3) and 1 had a deletion of 15q11q13 (Case 3). For all parameters, Case 3`s values were notably different from those of his unaffected sibling. The salivary flow rates and concentrations for all 3 PW patients are similar and are significantly different from normal controls (mean {plus_minus} SE) (p<0.05). Although this data is from only 3 PW patients, it provides valuable information. First, decreased flow appears to be due to an effect of PWS and not medications since Cases 2 & 3 are not on any medications. Second, decreased flow appears to be present in younger as well as older individuals. Third, deviations from normal in the salivary composition are evident. It is possible that these alterations are concentration effects relative to a decrease in flow rate. We are currently obtaining saliva from more PW individuals to see if these alterations are present in all PW patients and whether they can be applied as a screening test.

  6. High Resolution Continuous Flow Analysis System for Polar Ice Cores

    NASA Astrophysics Data System (ADS)

    Dallmayr, Remi; Azuma, Kumiko; Yamada, Hironobu; Kjær, Helle Astrid; Vallelonga, Paul; Azuma, Nobuhiko; Takata, Morimasa

    2014-05-01

    In the last decades, Continuous Flow Analysis (CFA) technology for ice core analyses has been developed to reconstruct the past changes of the climate system 1), 2). Compared with traditional analyses of discrete samples, a CFA system offers much faster and higher depth resolution analyses. It also generates a decontaminated sample stream without time-consuming sample processing procedure by using the inner area of an ice-core sample.. The CFA system that we have been developing is currently able to continuously measure stable water isotopes 3) and electrolytic conductivity, as well as to collect discrete samples for the both inner and outer areas with variable depth resolutions. Chemistry analyses4) and methane-gas analysis 5) are planned to be added using the continuous water stream system 5). In order to optimize the resolution of the current system with minimal sample volumes necessary for different analyses, our CFA system typically melts an ice core at 1.6 cm/min. Instead of using a wire position encoder with typical 1mm positioning resolution 6), we decided to use a high-accuracy CCD Laser displacement sensor (LKG-G505, Keyence). At the 1.6 cm/min melt rate, the positioning resolution was increased to 0.27mm. Also, the mixing volume that occurs in our open split debubbler is regulated using its weight. The overflow pumping rate is smoothly PID controlled to maintain the weight as low as possible, while keeping a safety buffer of water to avoid air bubbles downstream. To evaluate the system's depth-resolution, we will present the preliminary data of electrolytic conductivity obtained by melting 12 bags of the North Greenland Eemian Ice Drilling (NEEM) ice core. The samples correspond to different climate intervals (Greenland Stadial 21, 22, Greenland Stadial 5, Greenland Interstadial 5, Greenland Interstadial 7, Greenland Stadial 8). We will present results for the Greenland Stadial -8, whose depths and ages are between 1723.7 and 1724.8 meters, and 35.520 to

  7. Low Dissipative High Order Numerical Simulations of Supersonic Reactive Flows

    NASA Technical Reports Server (NTRS)

    Sjoegreen, B.; Yee, H. C.; Mansour, Nagi (Technical Monitor)

    2001-01-01

    The objective of this paper is to evaluate the performance of a newly developed low dissipative sixth-order spatial and fourth-order temporal scheme for viscous reactive flows interacting with shock waves that contain fine scale flow structures. The accuracy and efficiency of the scheme, and to what degree the scheme can capture the correct physical wave speeds of stiff reactive flows will be included.

  8. Neuroanatomic and cognitive abnormalities in attention-deficit/hyperactivity disorder in the era of 'high definition' neuroimaging.

    PubMed

    Baroni, Argelinda; Castellanos, F Xavier

    2015-02-01

    The ongoing release of the Human Connectome Project (HCP) data is a watershed event in clinical neuroscience. By attaining a quantum leap in spatial and temporal resolution within the framework of a twin/sibling design, this open science resource provides the basis for delineating brain-behavior relationships across the neuropsychiatric landscape. Here we focus on attention-deficit/hyperactivity disorder (ADHD), which is at least partly continuous across the population, highlighting constructs that have been proposed for ADHD and which are included in the HCP phenotypic battery. We review constructs implicated in ADHD (reward-related processing, inhibition, vigilant attention, reaction time variability, timing and emotional lability) which can be examined in the HCP data and in future 'high definition' clinical datasets.

  9. Abnormally High Content of Free Glucosamine Residues Identified in a Preparation of Commercially Available Porcine Intestinal Heparan Sulfate

    PubMed Central

    2016-01-01

    Heparan sulfate (HS) polysaccharides are ubiquitous in animal tissues as components of proteoglycans, and they participate in many important biological processes. HS carbohydrate chains are complex and can contain rare structural components such as N-unsubstituted glucosamine (GlcN). Commercially available HS preparations have been invaluable in many types of research activities. In the course of preparing microarrays to include probes derived from HS oligosaccharides, we found an unusually high content of GlcN residue in a recently purchased batch of porcine intestinal mucosal HS. Composition and sequence analysis by mass spectrometry of the oligosaccharides obtained after heparin lyase III digestion of the polysaccharide indicated two and three GlcN in the tetrasaccharide and hexasaccharide fractions, respectively. 1H NMR of the intact polysaccharide showed that this unusual batch differed strikingly from other HS preparations obtained from bovine kidney and porcine intestine. The very high content of GlcN (30%) and low content of GlcNAc (4.2%) determined by disaccharide composition analysis indicated that N-deacetylation and/or N-desulfation may have taken place. HS is widely used by the scientific community to investigate HS structures and activities. Great care has to be taken in drawing conclusions from investigations of structural features of HS and specificities of HS interaction with proteins when commercial HS is used without further analysis. Pending the availability of a validated commercial HS reference preparation, our data may be useful to members of the scientific community who have used the present preparation in their studies. PMID:27295282

  10. Flow separation in rocket nozzles under high altitude condition

    NASA Astrophysics Data System (ADS)

    Stark, R.; Génin, C.

    2016-03-01

    The knowledge of flow separation in rocket nozzles is crucial for rocket engine design and optimum performance. Typically, flow separation is studied under sea-level conditions. However, this disregards the change of the ambient density during ascent of a launcher. The ambient flow properties are an important factor concerning the design of altitude-adaptive rocket nozzles like the dual bell nozzle. For this reason an experimental study was carried out to study the influence of the ambient density on flow separation within conventional nozzles.

  11. Hot-wire coil probe for high-speed flows

    NASA Technical Reports Server (NTRS)

    Weinstein, L. M.

    1973-01-01

    Small-diameter-wire coil probes developed for use in a hypersonic helium tunnel are discussed. The springlike properties of the coil minimize strain-gauge effects, and allow to use a higher length-to-diameter ratio for a given flow. In addition, the coil is more rugged for sudden flow changes, and since it can be mounted straight across the support tips, there is less support interference in cross flows. In addition to measuring fluctuating quantities in a boundary layer, the probes were used with a constant temperature anemometer for measuring mean mass flow profiles, and with a constant current anemometer for measuring mean total temperature profiles.

  12. PDF methods for combustion in high-speed turbulent flows

    NASA Technical Reports Server (NTRS)

    Pope, Stephen B.

    1995-01-01

    This report describes the research performed during the second year of this three-year project. The ultimate objective of the project is extend the applicability of probability density function (pdf) methods from incompressible to compressible turbulent reactive flows. As described in subsequent sections, progress has been made on: (1) formulation and modelling of pdf equations for compressible turbulence, in both homogeneous and inhomogeneous inert flows; and (2) implementation of the compressible model in various flow configurations, namely decaying isotropic turbulence, homogeneous shear flow and plane mixing layer.

  13. Stratified wakes, the high Froude number approximation, and potential flow

    NASA Astrophysics Data System (ADS)

    Vasholz, David P.

    2011-12-01

    Properties of a steady wake generated by a body moving uniformly at constant depth through a stratified fluid are studied as a function of two parameters inserted into the linearized equations of motion. The first parameter, μ, multiplies the along-track gradient term in the source equation. When formal solutions for an arbitrary buoyancy frequency profile are written as eigenfunction expansions, one finds that the limit μ → 0 corresponds to a high Froude number approximation accompanied by a substantial reduction in the complexity of the calculation. For μ = 1, upstream effects are present and the eigenvalues correspond to critical speeds above which transverse waves disappear for any given mode. For sufficiently high modes, the high Froude number approximation is valid. The second tracer multiplies the square of the buoyancy frequency term in the linearized conservation of mass equation and enables direct comparisons with the limit of potential flow. Detailed results are given for the simplest possible profile, in which the buoyancy frequency is independent of depth; emphasis is placed upon quantities that can, in principle, be experimentally measured in a laboratory experiment. The vertical displacement field is written in terms of a stratified wake form factor {{H}} , which is the sum of a wavelike contribution that is non-zero downstream and an evanescent contribution that appears symmetrically upstream and downstream. First- and second-order cross-track moments of {{H}} are analyzed. First-order results predict enhanced upstream vertical displacements. Second-order results expand upon previous predictions of wavelike resonances and also predict evanescent resonance effects.

  14. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

  15. Brain abnormalities in high-risk violent offenders and their association with psychopathic traits and criminal recidivism.

    PubMed

    Leutgeb, V; Leitner, M; Wabnegger, A; Klug, D; Scharmüller, W; Zussner, T; Schienle, A

    2015-11-12

    Measures of psychopathy have been proved to be valuable for risk assessment in violent criminals. However, the neuronal basis of psychopathy and its contribution to the prediction of criminal recidivism is still poorly understood. We compared structural imaging data from 40 male high-risk violent offenders and 37 non-delinquent healthy controls via voxel-based morphometry. Psychopathic traits and risk of violence recidivism were correlated with gray matter volume (GMV) of regions of interest previously shown relevant for criminal behavior. Relative to controls, criminals showed less GMV in the prefrontal cortex (PFC) and more GMV in cerebellar regions and basal ganglia structures. Within criminals, we found a negative correlation between prefrontal GMV and psychopathy. Additionally, there was a positive correlation between cerebellar GMV and psychopathy as well as risk of recidivism for violence. Moreover, GMVs of the basal ganglia and supplementary motor area (SMA) were positively correlated with anti-sociality. GMV of the amygdala was negatively correlated with dynamic risk for violence recidivism. In contrast, GMV of (para)limbic areas (orbitofrontal cortex, insula) was positively correlated with anti-sociality and risk of violence recidivism. The current investigation revealed that in violent offenders deviations in GMV of the PFC as well as areas involved in the motor component of impulse control (cerebellum, basal ganglia, SMA) are differentially related to psychopathic traits and the risk of violence recidivism. The results might be valuable for improving existing risk assessment tools.

  16. Voluntary exercise contributed to an amelioration of abnormal feeding behavior, locomotor activity and ghrelin production concomitantly with a weight reduction in high fat diet-induced obese rats.

    PubMed

    Mifune, Hiroharu; Tajiri, Yuji; Nishi, Yoshihiro; Hara, Kento; Iwata, Shimpei; Tokubuchi, Ichiro; Mitsuzono, Ryouichi; Yamada, Kentaro; Kojima, Masayasu

    2015-09-01

    In the present study, effects of voluntary exercise in an obese animal model were investigated in relation to the rhythm of daily activity and ghrelin production. Male Sprague-Dawley rats were fed either a high fat diet (HFD) or a chow diet (CD) from four to 16 weeks old. They were further subdivided into either an exercise group (HFD-Ex, CD-Ex) with a running wheel for three days of every other week or sedentary group (HFD-Se, CD-Se). At 16 weeks old, marked increases in body weight and visceral fat were observed in the HFD-Se group, together with disrupted rhythms of feeding and locomotor activity. The induction of voluntary exercise brought about an effective reduction of weight and fat, and ameliorated abnormal rhythms of activity and feeding in the HFD-Ex rats. Wheel counts as voluntary exercise was greater in HFD-Ex rats than those in CD-Ex rats. The HFD-obese had exhibited a deterioration of ghrelin production, which was restored by the induction of voluntary exercise. These findings demonstrated that abnormal rhythms of feeding and locomotor activity in HFD-obese rats were restored by infrequent voluntary exercise with a concomitant amelioration of the ghrelin production and weight reduction. Because ghrelin is related to food anticipatory activity, it is plausible that ghrelin participates in the circadian rhythm of daily activity including eating behavior. A beneficial effect of voluntary exercise has now been confirmed in terms of the amelioration of the daily rhythms in eating behavior and physical activity in an animal model of obesity.

  17. Abnormalities in myo-inositol metabolism associated with type 2 diabetes in mice fed a high-fat diet: benefits of a dietary myo-inositol supplementation.

    PubMed

    Croze, Marine L; Géloën, Alain; Soulage, Christophe O

    2015-06-28

    We previously reported that a chronic supplementation with myo-inositol (MI) improved insulin sensitivity and reduced fat accretion in mice. We then tested the potency of such dietary intervention in the prevention of insulin resistance in C57BL/6 male mouse fed a high-fat diet (HFD). In addition, some abnormalities in inositol metabolism were reported to be associated with insulin resistance in several animal and human studies. We then investigated the presence of such anomalies (i.e. inosituria and an inositol intra-tissue depletion) in this diet-induced obesity (DIO) mouse model, as well as the potential benefit of a MI supplementation for inositol intra-tissue deficiency correction. HFD (60 % energy from fat) feeding was associated with inosituria and inositol intra-tissue depletion in the liver and kidneys. MI supplementation (0·58 mg/g per d) restored inositol pools in kidneys (partially) and liver (fully). HFD feeding for 4 months induced ectopic lipid redistribution to liver and muscles, fasting hyperglycaemia and hyperinsulinaemia, insulin resistance and obesity that were not prevented by MI supplementation, despite a significant improvement in insulin sensitivity parameter K insulin tolerance test and a reduction in white adipose tissue (WAT) mass ( - 17 %, P< 0·05). MI supplementation significantly reduced fatty acid synthase activity in epididymal WAT, which might explain its beneficial, but modest, effect on WAT accretion in HFD-fed mice. Finally, we found some abnormalities in inositol metabolism in association with a diabetic phenotype (i.e. insulin resistance and fasting hyperglycaemia) in a DIO mouse model. Dietary MI supplementation was efficient in the prevention of inositol intra-tissue depletion, but did not prevent insulin resistance or obesity efficiently in this mouse model. PMID:25990651

  18. Abnormalities in myo-inositol metabolism associated with type 2 diabetes in mice fed a high-fat diet: benefits of a dietary myo-inositol supplementation.

    PubMed

    Croze, Marine L; Géloën, Alain; Soulage, Christophe O

    2015-06-28

    We previously reported that a chronic supplementation with myo-inositol (MI) improved insulin sensitivity and reduced fat accretion in mice. We then tested the potency of such dietary intervention in the prevention of insulin resistance in C57BL/6 male mouse fed a high-fat diet (HFD). In addition, some abnormalities in inositol metabolism were reported to be associated with insulin resistance in several animal and human studies. We then investigated the presence of such anomalies (i.e. inosituria and an inositol intra-tissue depletion) in this diet-induced obesity (DIO) mouse model, as well as the potential benefit of a MI supplementation for inositol intra-tissue deficiency correction. HFD (60 % energy from fat) feeding was associated with inosituria and inositol intra-tissue depletion in the liver and kidneys. MI supplementation (0·58 mg/g per d) restored inositol pools in kidneys (partially) and liver (fully). HFD feeding for 4 months induced ectopic lipid redistribution to liver and muscles, fasting hyperglycaemia and hyperinsulinaemia, insulin resistance and obesity that were not prevented by MI supplementation, despite a significant improvement in insulin sensitivity parameter K insulin tolerance test and a reduction in white adipose tissue (WAT) mass ( - 17 %, P< 0·05). MI supplementation significantly reduced fatty acid synthase activity in epididymal WAT, which might explain its beneficial, but modest, effect on WAT accretion in HFD-fed mice. Finally, we found some abnormalities in inositol metabolism in association with a diabetic phenotype (i.e. insulin resistance and fasting hyperglycaemia) in a DIO mouse model. Dietary MI supplementation was efficient in the prevention of inositol intra-tissue depletion, but did not prevent insulin resistance or obesity efficiently in this mouse model.

  19. Highly sensitive flow-injection chemiluminescence determination of pyrogallol compounds

    NASA Astrophysics Data System (ADS)

    Kanwal, Shamsa; Fu, Xiaohong; Su, Xingguang

    2009-12-01

    A highly sensitive flow-injection chemiluminescent method for the direct determination of pyrogallol compounds has been developed. Proposed method is based on the enhanced effect of pyrogallol compounds on the chemiluminescence signals of KMnO 4-H 2O 2 system in slightly alkaline medium. Three important pyrogallol compounds, pyrogallic acid, gallic acid and tannic acid, have been detected by this method, and the possible mechanism of the CL reaction is also discussed. The proposed method is simple, convenient, rapid (60 samples h -1), and sensitive, has a linear range of 8 × 10 -10 mol L -1 to 1 × 10 -5 mol L -1, for pyrogallic acid, with a detection limit of 6 × 10 -11 mol L -1, 4 × 10 -8 mol L -1 to 5 × 10 -3 mol L -1 for gallic acid with a detection limit of 9 × 10 -10 mol L -1, and 8 × 10 -8 mol L -1 to 5 × 10 -2 mol L -1 for tannic acid, with a detection limit of 2 × 10 -9 mol L -1, respectively. The relative standard deviation (RSD, n = 15) was 0.8, 1.1 and 1.3% for 5 × 10 -6 mol L -1 pyrogallic acid, gallic acid and tannic acid, respectively. The proposed method was successfully applied to the determination of pyrogallol compounds in tea and coffee samples.

  20. Two-dimensional, high flow, precisely controlled monodisperse drop source

    NASA Astrophysics Data System (ADS)

    Dressler, John L.

    1993-03-01

    A versatile acoustically-driven fluid atomizer was designed and operated that creates precise monodisperse sprays by Rayleigh breakup or polydisperse sprays by the acoustic driving of amplitude dependent instabilities. The atomizer forms a cylindrical, conical, or flat (sheet) liquid jet by means of a photofabricated nozzle. The spray pattern and spray volume are altered by changing the nozzle. A piezoelectric driver, constructed to efficiently couple energy to the liquid, modulates the fluid velocity. When operated at low power, the drop generator can produce arrays of monodisperse drops as small as 15 microns in diameter. Operating the piezoelectric driver at high power produces perturbations with sufficient energy to break the liquid jets into drops, with a net increase in surface energy. The resulting drop sizes are influenced by the frequency and amplitude of the driving signal and nozzle size. The spatial distribution of the spray is controlled by the spacing and geometry of the holes in the nozzle plate, the amplitude of the acoustic signal, and the swirl in the fluid manifold. This device is more robust than the typical acoustic drop generator because small drops can be made from large holes, reducing the plugging problem. No air flow is used.

  1. Vitiated ethane oxidation in a high-pressure flow reactor

    SciTech Connect

    Walters, K.M.; Bowman, C.T.

    2009-10-15

    Vitiated combustion processes offer the potential to improve the thermodynamic efficiency in hydrocarbon-fueled combustion systems, providing a subsequent decrease in energy-specific CO{sub 2} emissions along with a decrease in the emission levels of nitrogen oxides (NO{sub x}) and particulate matter. The present work comprises an experimental and modeling study of vitiated ethane oxidation in a high-pressure flow reactor, with pressures of 1-6 bar, O{sub 2} mole fractions of 3.5-7.0%, temperatures of 1075-1100 K and 15-18 mole.% H{sub 2}O. Time-history measurements of species are used to characterize the overall rate of reaction and track the fuel-carbon through intermediate and product species. A one-dimensional mixing-reacting model that accounts for partial oxidation during reactant mixing is used in conjunction with a detailed kinetic mechanism. Changes in competing pathways due to variations in pressure and O{sub 2} mole fraction give rise to the complex pressure dependence seen in the experiments. (author)

  2. Capillary flow of amorphous metal for high performance electrode.

    PubMed

    Kim, Se Yun; Kim, Suk Jun; Jee, Sang Soo; Park, Jin Man; Park, Keum Hwan; Park, Sung Chan; Cho, Eun Ae; Lee, Jun Ho; Song, In Yong; Lee, Sang Mock; Han, In Taek; Lim, Ka Ram; Kim, Won Tae; Park, Ju Cheol; Eckert, Jürgen; Kim, Do Hyang; Lee, Eun-Sung

    2013-01-01

    Metallic glass (MG) assists electrical contact of screen-printed silver electrodes and leads to comparable electrode performance to that of electroplated electrodes. For high electrode performance, MG needs to be infiltrated into nanometer-scale cavities between Ag particles and reacts with them. Here, we show that the MG in the supercooled state can fill the gap between Ag particles within a remarkably short time due to capillary effect. The flow behavior of the MG is revealed by computational fluid dynamics and density funtional theory simulation. Also, we suggest the formation mechanism of the Ag electrodes, and demonstrate the criteria of MG for higher electrode performance. Consequently, when Al85Ni5Y8Co2 MG is added in the Ag electrodes, cell efficiency is enhanced up to 20.30% which is the highest efficiency reported so far for screen-printed interdigitated back contact solar cells. These results show the possibility for the replacement of electroplating process to screen-printing process.

  3. EXPLORING A 'FLOW' OF HIGHLY ECCENTRIC BINARIES WITH KEPLER

    SciTech Connect

    Dong Subo; Katz, Boaz; Socrates, Aristotle

    2013-01-20

    With 16-month of Kepler data, 15 long-period (40-265 days) eclipsing binaries on highly eccentric orbits (minimum e between 0.5 and 0.85) are identified from their closely separated primary and secondary eclipses ({Delta}t{sub I,II} = 3-10 days). These systems confirm the existence of a previously hinted binary population situated near a constant angular momentum track at P(1 - e {sup 2}){sup 3/2} {approx} 15 days, close to the tidal circularization period P{sub circ}. They may be presently migrating due to tidal dissipation and form a steady-state 'flow' ({approx}1% of stars) feeding the close-binary population (few % of stars). If so, future Kepler data releases will reveal a growing number (dozens) of systems at longer periods, following dN/dlgP {proportional_to} P {sup 1/3} with increasing eccentricities reaching e {yields} 0.98 for P {yields} 1000 days. Radial-velocity follow-up of long-period eclipsing binaries with no secondary eclipses could offer a significantly larger sample. Orders of magnitude more (hundreds) may reveal their presence from periodic 'eccentricity pulses', such as tidal ellipsoidal variations near pericenter passages. Several new few-day-long eccentricity-pulse candidates with long periods (P = 25-80 days) are reported.

  4. [Abnormal cerebral blood flow distributions during the post-ictal phase of febrile status epilepticus in three pediatric patients measured by arterial spin labeling perfusion MRI].

    PubMed

    Hirano, Keiko; Fukuda, Tokiko

    2016-05-01

    The ability to visualize brain perfusion is important for identifying epileptic foci. We present three pediatric cases showing asymmetrical cerebral blood flow (CBF) distributions during the post-ictal phase of febrile status epilepticus measured by arterial spin labeling (ASL) perfusion MRI. During the acute phase, regional CBF measurements in the areas considered including epileptic foci were higher than in the corresponding area of the contralateral hemisphere, though the exact quantitative value varied between cases. We could not identify the correct epileptogenic foci, because those ASL images were taken after the prolonged and extraordinary activation of neurons in the affected area. During the recovery phase, the differences reduced and the average regional CBF measurement was 54.6 ± 6.1 ml/100 g per minute, which was a little less than the number of previous ASL studies. ASL perfusion MRI imaging provides a method for evaluating regional CBF by using magnetically labeled arterial blood water as an endogenous tracer. With this technique, we can repeatedly evaluate both the brain structure and the level of perfusion at the same time. ASL is noninvasive and easily accessible, and therefore it could become a routine tool for assessment of perfusion in daily practice of pediatric neurology. PMID:27349086

  5. Structurally abnormal human autosomes

    SciTech Connect

    1993-12-31

    Chapter 25, discusses structurally abnormal human autosomes. This discussion includes: structurally abnormal chromosomes, chromosomal polymorphisms, pericentric inversions, paracentric inversions, deletions or partial monosomies, cri du chat (cat cry) syndrome, ring chromosomes, insertions, duplication or pure partial trisomy and mosaicism. 71 refs., 8 figs.

  6. Voxel-wise meta-analyses of brain blood flow and local synchrony abnormalities in medication-free patients with major depressive disorder

    PubMed Central

    Chen, Zi-Qi; Du, Ming-Ying; Zhao, You-Jin; Huang, Xiao-Qi; Li, Jing; Lui, Su; Hu, Jun-Mei; Sun, Huai-Qiang; Liu, Jia; Kemp, Graham J.; Gong, Qi-Yong

    2015-01-01

    Background Published meta-analyses of resting-state regional cerebral blood flow (rCBF) studies of major depressive disorder (MDD) have included patients receiving antidepressants, which might affect brain activity and thus bias the results. To our knowledge, no meta-analysis has investigated regional homogeneity changes in medication-free patients with MDD. Moreover, an association between regional homogeneity and rCBF has been demonstrated in some brain regions in healthy controls. We sought to explore to what extent resting-state rCBF and regional homogeneity changes co-occur in the depressed brain without the potential confound of medication. Methods Using the effect-size signed differential mapping method, we conducted 2 meta-analyses of rCBF and regional homogeneity studies of medication-free patients with MDD. Results Our systematic search identified 14 rCBF studies and 9 regional homogeneity studies. We identified conjoint decreases in resting-state rCBF and regional homogeneity in the insula and superior temporal gyrus in medication-free patients with MDD compared with controls. Other changes included altered resting-state rCBF in the precuneus and in the frontal–limbic–thalamic–striatal neural circuit as well as altered regional homogeneity in the uncus and parahippocampal gyrus. Meta-regression revealed that the percentage of female patients with MDD was negatively associated with resting-state rCBF in the right anterior cingulate cortex and that the age of patients with MDD was negatively associated with rCBF in the left insula and with regional homogeneity in the left uncus. Limitations The analysis techniques, patient characteristics and clinical variables of the included studies were heterogeneous. Conclusion The conjoint alterations of rCBF and regional homogeneity in the insula and superior temporal gyrus may be core neuropathological changes in medication-free patients with MDD and serve as a specific region of interest for further studies

  7. Morphological abnormalities among lampreys

    USGS Publications Warehouse

    Manion, Patrick J.

    1967-01-01

    The experimental control of the sea lamprey (Petromyzon marinus) in the Great Lakes has required the collection of thousands of lampreys. Representatives of each life stage of the four species of the Lake Superior basin were examined for structural abnormalities. The most common aberration was the presence of additional tails. The accessory tails were always postanal and smaller than the normal tail. The point of origin varied; the extra tails occurred on dorsal, ventral, or lateral surfaces. Some of the extra tails were misshaped and curled, but others were normal in shape and pigment pattern. Other abnormalities in larval sea lampreys were malformed or twisted tails and bodies. The cause of the structural abnormalities is unknown. The presence of extra caudal fins could be genetically controlled, or be due to partial amputation or injury followed by abnormal regeneration. Few if any lampreys with structural abnormalities live to sexual maturity.

  8. Percutaneous Direct Puncture Embolization with N-butyl-cyanoacrylate for High-flow Priapism.

    PubMed

    Tokue, Hiroyuki; Shibuya, Kei; Ueno, Hiroyuki; Tokue, Azusa; Tsushima, Yoshito

    2016-09-01

    There are many treatment options in high-flow priapism. Those mentioned most often are watchful waiting, Doppler-guided compression, endovascular highly selective embolization, and surgery. We present a case of high-flow priapism in a 57-year-old man treated by percutaneous direct puncture embolization of a post-traumatic left cavernosal arteriovenous fistula using N-butyl-cyanoacrylate. Erectile function was preserved during a 12-month follow-up. No patients with percutaneous direct puncture embolization for high-flow priapism have been reported previously. Percutaneous direct puncture embolization is a potentially useful and safe method for management of high-flow priapism.

  9. Tailoring Inlet Flow to Enable High Accuracy Compressor Performance Measurements

    NASA Astrophysics Data System (ADS)

    Brossman, John R.; Smith, Natalie R.; Talalayev, Anton; Key, Nicole L.

    2011-12-01

    To accomplish the research goals of capturing the effects of blade row interactions on compressor performance, small changes in performance must be measurable. This also requires axi-symmetric flow so that measuring one passage accurately captures the phenomena occurring in all passages. Thus, uniform inlet flow is a necessity. The original front-driven compressor had non-uniform temperature at the inlet. Additional challenges in controlling shaft speed to within tight tolerances were associated with the use of a viscous fluid coupling. Thus, a new electric motor, with variable frequency drive speed control was implemented. To address the issues with the inlet flow, the compressor is now driven from the rear resulting in improved inlet flow uniformity. This paper presents the design choices of the new layout in addition to the preliminary performance data of the compressor and an uncertainty analysis.

  10. The Impact of High-Risk HPV Genotypes Other Than HPV 16/18 on the Natural Course of Abnormal Cervical Cytology: A Korean HPV Cohort Study

    PubMed Central

    So, Kyeong A; Kim, Mi Jung; Lee, Ki-Heon; Lee, In-Ho; Kim, Mi Kyung; Lee, Yoo Kyung; Hwang, Chang-Sun; Jeong, Mi Seon; Kee, Mee-Kyung; Kang, Chun; Cho, Chi Heum; Kim, Seok Mo; Hong, Sung Ran; Kim, Ki Tae; Lee, Won-Chul; Park, Jong Sup; Kim, Tae Jin

    2016-01-01

    Purpose The purpose of this study is to evaluate the impact of high-risk human papillomaviruses (HPVs) other than HPV 16/18 on the natural course of atypical squamous cells of undetermined significance (ASC-US) or low-grade squamous intraepithelial lesion (LSIL). Materials and Methods The study population was derived from the Korean HPV cohort (2010-2014). Women aged 20 to 60 who satisfied the criteria of having both HPV infection and abnormal cervical cytology of either ASC-US or LSIL were recruited from five institutions nationwide. Enrolled patients underwent cervical cytology and HPV DNA testing every 6 months. Results A total of 1,158 patients were enrolled. The 10 most common HPV types were HPV 16 (12.3%), 58 (10.0%), 56 (8.8%), 53 (8.4%), 52 (7.7%), 39 (6.2%), 18 (6.0%), 51 (5.7%), 68 (5.1%), and 66 (4.6%). Among these patients, 636 women were positive for high-risk HPVs other than HPV 16 or 18, and 429 women were followed for more than 6 months. Cytology evaluations showed progression in 15.3% of women, no change in 22.6%, and regression in 62.1% of women at 12 months. In cases of HPV 58 single infection, a more highly significant progression rate, compared to other high-risk types, was observed at 6 months (relative risk [RR], 3.3; 95% confidence interval [CI], 2.04 to 5.30; p < 0.001) and 12 months (RR, 5.03; 95% CI, 2.56 to 9.91; p < 0.001). Conclusion HPV genotypes numbered in the 50s were frequent in Korean women with ASC-US and LSIL. HPV 58 was the second most common type, with a high progression rate of cervical cytology. PMID:26987394

  11. Microfluidic Impedance Flow Cytometry Enabling High-Throughput Single-Cell Electrical Property Characterization

    PubMed Central

    Chen, Jian; Xue, Chengcheng; Zhao, Yang; Chen, Deyong; Wu, Min-Hsien; Wang, Junbo

    2015-01-01

    This article reviews recent developments in microfluidic impedance flow cytometry for high-throughput electrical property characterization of single cells. Four major perspectives of microfluidic impedance flow cytometry for single-cell characterization are included in this review: (1) early developments of microfluidic impedance flow cytometry for single-cell electrical property characterization; (2) microfluidic impedance flow cytometry with enhanced sensitivity; (3) microfluidic impedance and optical flow cytometry for single-cell analysis and (4) integrated point of care system based on microfluidic impedance flow cytometry. We examine the advantages and limitations of each technique and discuss future research opportunities from the perspectives of both technical innovation and clinical applications. PMID:25938973

  12. Numerical simulation of high speed chemically reacting flows

    NASA Astrophysics Data System (ADS)

    Schuricht, Scott Richard

    A single step second-order accurate flux-difference-splitting method has been developed for solving unsteady quasi-one-dimensional and two-dimensional flows of multispecies fluids with finite rate chemistry. A systematic method for incorporating the source term effects into the wave strength parameters of Roe's linearized approximate Riemann solver is presented that is consistent with characteristic theory. The point implicit technique is utilized to achieve second-order time accuracy of the local area source term The stiffness associated with the chemical reactions is removed by implicitly integrating the kinetics system using the LSODE package. From the implicit integration, values of the species production rates are developed and incorporated into the flux-difference-splitting framework using a source term projection and splitting technique that preserves the upwind nature of source terms. Numerous validation studies are presented to illustrate the capability of the numerical method. Shock tube and converging-diverging nozzle cases show the method is second order accurate in space and time for one-dimensional flows. A supersonic source flow case and a subsonic sink flow case show the method is second order spatially accurate for two-dimensional flows. Static combustion and steady supersonic combustion cases illustrate the ability of the method to accurately capture the ignition delay for hydrogen-air mixtures. Demonstration studies are presented to illustrate the capabilities of the method. One-dimensional flow in a shock tube predicts species dissociation behind the main shock wave. One-dimension flow in supersonic nozzles predicts the well-known chemical freezing effect in an expanding flow. Two-dimensional cases consisted of a model of a scramjet combustor and a rocket motor nozzle. A parametric study was performed on a model of a scramjet combustor. The parameters studied were; wall angle, inlet Mach number, inlet temperature, and inlet equivalence ratio

  13. High-Flow, High-Molecular-Weight, Addition-Curing Polyimides

    NASA Technical Reports Server (NTRS)

    Chuang, Kathy C.; Vannucci, Raymond D.

    1993-01-01

    In developed series of high-flow PMR-type polyimide resins, 2, 2'-bis(trifluoromethyl)-4, 4'-diaminobiphenyl (BTDB) substituted for 1, 4-pheylenediamine in PMR-II formulation. Polyimides designated either as PMR-12F when nadic ester (NE) end caps used, or as V-CAP-12F when p-aminostyrene end caps used. High-molecular-weight, addition-curing polyimides based on BTBD and HFDE highly processable high-temperature matrix resins used to make composite materials with excellent retention of properties during long-term exposure to air at 650 degrees F or higher temperature. Furthermore, 12F addition-curing polyimides useful for electronic applications; fluorinated rigid-rod polyimides known to exhibit low thermal expansion coefficients as well as low absorption of moisture.

  14. Vortex design of a diagonal flow impeller with high specific speed

    NASA Astrophysics Data System (ADS)

    Kamada, Yoshihisa; Yamaguchi, Sumio; Sasaki, Kazuto; Inoue, Masahiro

    1986-09-01

    The 'vortex design' method applied to an axial flow compressor stage has been extended to a diagonal flow impeller with high specific speed. For a given type of vortex flow, the through flow problem is solved by the streamline curvature method, and a blade element is determined on the basis of this solution. However, for any vortex type except free vortex, the exit flow condition changes due to a secondary flow induced by vortices shed from the trailing edges. The given vortex type can be obtained by correcting this effect with a so-called secondary flow theory.The validity of this method has been examined in experiments on three kinds of vortex flows: free vortex type, and constant tangential velocity types with or without correction of the secondary flow effects.

  15. TEMPO-based catholyte for high-energy density nonaqueous redox flow batteries.

    PubMed

    Wei, Xiaoliang; Xu, Wu; Vijayakumar, Murugesan; Cosimbescu, Lelia; Liu, Tianbiao; Sprenkle, Vincent; Wang, Wei

    2014-12-01

    A TEMPO-based non-aqueous electrolyte with the TEMPO concentration as high as 2.0 m is demonstrated as a high-energy-density catholyte for redox flow battery applications. With a hybrid anode, Li|TEMPO flow cells using this electrolyte deliver an energy efficiency of ca. 70% and an impressively high energy density of 126 W h L(-1) .

  16. Large eddy simulations and direct numerical simulations of high speed turbulent reacting flows

    NASA Technical Reports Server (NTRS)

    Givi, Peyman; Madnia, Cyrus K.; Steinberger, Craig J.

    1990-01-01

    This research is involved with the implementation of advanced computational schemes based on large eddy simulations (LES) and direct numerical simulations (DNS) to study the phenomenon of mixing and its coupling with chemical reactions in compressible turbulent flows. In the efforts related to LES, a research program to extend the present capabilities of this method was initiated for the treatment of chemically reacting flows. In the DNS efforts, the focus is on detailed investigations of the effects of compressibility, heat release, and non-equilibrium kinetics modelings in high speed reacting flows. Emphasis was on the simulations of simple flows, namely homogeneous compressible flows, and temporally developing high speed mixing layers.

  17. Adapting high-level language programs for parallel processing using data flow

    NASA Technical Reports Server (NTRS)

    Standley, Hilda M.

    1988-01-01

    EASY-FLOW, a very high-level data flow language, is introduced for the purpose of adapting programs written in a conventional high-level language to a parallel environment. The level of parallelism provided is of the large-grained variety in which parallel activities take place between subprograms or processes. A program written in EASY-FLOW is a set of subprogram calls as units, structured by iteration, branching, and distribution constructs. A data flow graph may be deduced from an EASY-FLOW program.

  18. Characterization of medium and high flow series 1500 LARC-TPI

    NASA Technical Reports Server (NTRS)

    Burks, H. D.; St. Clair, T. L.; Gautreaux, C. R.

    1990-01-01

    An imidized version of LARC-TPI was developed on NASA's request for use by both aerospace and electronic industries. Two batches of LARC-TPI 1500 Series, consisting of medium-flow and high-flow pellets with different inherent viscosities, are characterized for their dynamic and isothermal melt flow properties at 340 C, mechanical properties of extrudates, extrudate porosity, and degree of crystallinity. The Series shows significantly better melt flow properties than previosly examimed forms of this polymer.

  19. Abnormal uterine bleeding.

    PubMed

    Jennings, J C

    1995-11-01

    Physicians who care for female patients cannot avoid the frequent complaint of abnormal uterine bleeding. Knowledge of the disorders that cause this problem can prevent serious consequences in many patients and improve the quality of life for many others. The availability of noninvasive and minimally invasive diagnostic studies and minimally invasive surgical treatment has revolutionized management of abnormal uterine bleeding. Similar to any other disorder, the extent to which a physician manages abnormal uterine bleeding depends on his or her own level of comfort. When limitations of either diagnostic or therapeutic capability are encountered, consultation and referral should be used to the best interest of patients.

  20. Blood flow measurement using a highly filled carbon polymer sandwich sensor and an elasto-pseudo compressible vascular flow.

    PubMed

    Mehdian, M; Rahnejat, H

    1996-01-01

    Vascular grafts are widely employed in clinical practice and still pose significant problems of compatibility and longevity, particularly when the prosthesis is to replace arteries of small diameter. Once a graft has been implanted in the vascular tree, there is no easy way of assessing its interactions with the surrounding tissue. Doppler flow probes or some imaging techniques are commonly used to monitor flow velocity in vascular prostheses. It is, however, difficult to monitor a patient's recovery on a continuous basis. Continuous means of measurement can be quite invaluable. This paper presents a high-carbon filled polymer (HCFP) sensor that is developed for blood flow measurement in vascular grafts. Furthermore, a computational fluid dynamics model of incompressible blood flow in elastic blood vessels is presented. PMID:9046189

  1. High resolution solutions of the Euler equations for vortex flows

    NASA Technical Reports Server (NTRS)

    Murman, E. M.; Powell, K. G.; Rizzi, A.

    1985-01-01

    Solutions of the Euler equations are presented for M = 1.5 flow past a 70-degree-swept delta wing. At an angle of attack of 10 degrees, strong leading-edge vortices are produced. Two computational approaches are taken, based upon fully three-dimensional and conical flow theory. Both methods utilize a finite-volume discretization solved by a pseudounsteady multistage scheme. Results from the two approaches are in good agreement. Computations have been done on a 16-million-word CYBER 205 using 196 x 56 x 96 and 128 x 128 cells for the two methods. A sizable data base is generated, and some of the practical aspects of manipulating it are mentioned. The results reveal many interesting physical features of the compressible vortical flow field and also suggest new areas needing research.

  2. Flow and diffusion of high-stakes test scores

    NASA Astrophysics Data System (ADS)

    Marder, M.; Bansal, D.

    2009-10-01

    We apply visualization and modeling methods for convective and diffusive flows to public school mathematics test scores from Texas. We obtain plots that show the most likely future and past scores of students, the effects of random processes such as guessing, and the rate at which students appear in and disappear from schools. We show that student outcomes depend strongly upon economic class, and identify the grade levels where flows of different groups diverge most strongly. Changing the effectiveness of instruction in one grade naturally leads to strongly nonlinear effects on student outcomes in subsequent grades.

  3. Long-Term Administration of High-Fat Diet Corrects Abnormal Bone Remodeling in the Tibiae of Interleukin-6-Deficient Mice.

    PubMed

    Feng, Wei; Liu, Bo; Liu, Di; Hasegawa, Tomoka; Wang, Wei; Han, Xiuchun; Cui, Jian; Yimin; Oda, Kimimitsu; Amizuka, Norio; Li, Minqi

    2016-01-01

    In this study, we aimed to evaluate the influence of diet-induced obesity on IL-6 deficiency-induced bone remodeling abnormality. Seven-week-old IL-6(-/-) mice and their wild type (WT) littermates were fed a standard diet (SD) or high-fat diet (HFD) for 25 weeks. Lipid formation and bone metabolism in mice tibiae were investigated by histochemical analysis. Both IL-6(-/-) and WT mice fed the HFD showed notable body weight gain, thickened cortical bones, and adipose accumulation in the bone marrow. Notably, the HFD normalized the bone phenotype of IL-6(-/-) mice to that of their WT counterpart, as characterized by a decrease in bone mass and the presence of an obliquely arranged, plate-like morphology in the trabecular bone. Alkaline phosphatase and osteocalcin expressions were attenuated in both genotypes after HFD feeding, especially for the IL-6(-/-) mice. Meanwhile, tartrate-resistant acid phosphatase staining was inhibited, osteoclast apoptosis rate down-regulated (revealed by TUNEL assay), and the proportion of cathepsin K (CK)-positive osteoclasts significantly increased in IL-6(-/-) mice on a HFD as compared with IL-6(-/-) mice on standard chow. Our results demonstrate that HFD-induced obesity reverses IL-6 deficiency-associated bone metabolic disorders by suppressing osteoblast activity, upregulating osteoclastic activity, and inhibiting osteoclast apoptosis. PMID:26416243

  4. Development and validation of an high-performance liquid chromatography-diode array detector method for the simultaneous determination of six phenolic compounds in abnormal savda munziq decoction

    PubMed Central

    Tian, Shuge; Liu, Wenxian; Liu, Feng; Zhang, Xuejia; Upur, Halmuart

    2015-01-01

    Aims: Given the high-effectiveness and low-toxicity of abnormal savda munziq (ASMQ), its herbal formulation has long been used in traditional Uyghur medicine to treat complex diseases, such as cancer, diabetes, and cardiovascular diseases. Settings and Design: ASMQ decoction by reversed-phase high-performance liquid chromatography coupled with a diode array detector was successfully developed for the simultaneous quality assessment of gallic acid, protocatechuic acid, caffeic acid, rutin, rosmarinic acid, and luteolin. The six phenolic compounds were separated on an Agilent TC-C18 reversed-phase analytical column (4.6 × 250 mm, 5 μm) by gradient elution using 0.3% aqueous formic acid (v/v) and 0.3% methanol formic acid (v/v) at 1.0 mL/min. Materials and Methods: The plant material was separately ground and mixed at the following ratios (10): Cordia dichotoma (10.6), Anchusa italic (10.6), Euphorbia humifusa (4.9), Adiantum capillus-veneris (4.9), Ziziphus jujube (4.9), Glycyrrhiza uralensis (7.1), Foeniculum vulgare (4.9), Lavandula angustifolia (4.9), Dracocephalum moldavica L. (4.9), and Alhagi pseudoalhagi (42.3). Statistical Analysis Used: The precisions of all six compounds were <0.60%, and the average recoveries ranged from 99.39% to 104.85%. Highly significant linear correlations were found between component concentrations and specific chromatographic peak areas (R2 > 0.999). Results: The proposed method was successfully applied to determine the levels of six active components in ASMQ. Conclusions: Given the simplicity, precision, specificity, and sensitivity of the method, it can be utilized as a quality control approach to simultaneously determining the six phenolic compounds in AMSQ. PMID:25709227

  5. "Jeopardy" in Abnormal Psychology.

    ERIC Educational Resources Information Center

    Keutzer, Carolin S.

    1993-01-01

    Describes the use of the board game, Jeopardy, in a college level abnormal psychology course. Finds increased student interaction and improved application of information. Reports generally favorable student evaluation of the technique. (CFR)

  6. Abnormal Uterine Bleeding

    MedlinePlus

    ... Abnormal uterine bleeding is any bleeding from the uterus (through your vagina) other than your normal monthly ... or fibroids (small and large growths) in the uterus can also cause bleeding. Rarely, a thyroid problem, ...

  7. Abnormal Uterine Bleeding FAQ

    MedlinePlus

    ... as cancer of the uterus, cervix, or vagina • Polycystic ovary syndrome How is abnormal bleeding diagnosed? Your health care ... before the fetus can survive outside the uterus. Polycystic Ovary Syndrome: A condition characterized by two of the following ...

  8. Molecular cloud formation in high-shear, magnetized colliding flows

    NASA Astrophysics Data System (ADS)

    Fogerty, E.; Frank, A.; Heitsch, F.; Carroll-Nellenback, J.; Haig, C.; Adams, M.

    2016-08-01

    The colliding flows (CF) model is a well-supported mechanism for generating molecular clouds. However, to-date most CF simulations have focused on the formation of clouds in the normal-shock layer between head-on colliding flows. We performed simulations of magnetized colliding flows that instead meet at an oblique-shock layer. Oblique shocks generate shear in the post-shock environment, and this shear creates inhospitable environments for star formation. As the degree of shear increases (i.e. the obliquity of the shock increases), we find that it takes longer for sink particles to form, they form in lower numbers, and they tend to be less massive. With regard to magnetic fields, we find that even a weak field stalls gravitational collapse within forming clouds. Additionally, an initially oblique collision interface tends to reorient over time in the presence of a magnetic field, so that it becomes normal to the oncoming flows. This was demonstrated by our most oblique shock interface, which became fully normal by the end of the simulation.

  9. Absorption Filter Based Optical Diagnostics in High Speed Flows

    NASA Technical Reports Server (NTRS)

    Samimy, Mo; Elliott, Gregory; Arnette, Stephen

    1996-01-01

    Two major regimes where laser light scattered by molecules or particles in a flow contains significant information about the flow are Mie scattering and Rayleigh scattering. Mie scattering is used to obtain only velocity information, while Rayleigh scattering can be used to measure both the velocity and the thermodynamic properties of the flow. Now, recently introduced (1990, 1991) absorption filter based diagnostic techniques have started a new era in flow visualization, simultaneous velocity and thermodynamic measurements, and planar velocity measurements. Using a filtered planar velocimetry (FPV) technique, we have modified the optically thick iodine filter profile of Miles, et al., and used it in the pressure-broaden regime which accommodates measurements in a wide range of velocity applications. Measuring velocity and thermodynamic properties simultaneously, using absorption filtered based Rayleigh scattering, involves not only the measurement of the Doppler shift, but also the spectral profile of the Rayleigh scattering signal. Using multiple observation angles, simultaneous measurement of one component velocity and thermodynamic properties in a supersonic jet were measured. Presently, the technique is being extended for simultaneous measurements of all three components of velocity and thermodynamic properties.

  10. High speed viscous flow calculations about complex configurations

    NASA Technical Reports Server (NTRS)

    Chaussee, D. S.

    1986-01-01

    Applications of the NASA Ames Parabolized Navier-Stokes (PNS) code to a variety of complex generic configurations is presented. The algorithm, boundary conditions, initial conditions, and grid generators are discussed as applied to these configurations. The PNS code was used as the mainline procedure to numerically simulate the viscous supersonic flow over these generic configurations. The turbulence model that was used in this study is the Baldwin-Lomax model. The boundary conditions are the usual viscous no slip at the wall, and a characteristic procedure is used to fit the bow shock wave which is the outermost boundary. An elliptic grid generator is employed to discretize the flow domain. In addition, an equilibrium air capability has been incorporated into the code. It uses the curve fits of Tannehill, et al. The flow regimes vary from a Mach number of 2 up to 25. Both laminar and turbulent flow are considered. Varying angles of attack have also been computed. Configurations vary from simple cone-type bodies to lifting winged bodies, such as the space shuttle or the generic supersonic cruise fighter.

  11. High speed viscous flow calculations about complex configurations

    NASA Astrophysics Data System (ADS)

    Chaussee, D. S.

    1986-04-01

    Applications of the NASA Ames Parabolized Navier-Stokes (PNS) code to a variety of complex generic configurations is presented. The algorithm, boundary conditions, initial conditions, and grid generators are discussed as applied to these configurations. The PNS code was used as the mainline procedure to numerically simulate the viscous supersonic flow over these generic configurations. The turbulence model that was used in this study is the Baldwin-Lomax model. The boundary conditions are the usual viscous no slip at the wall, and a characteristic procedure is used to fit the bow shock wave which is the outermost boundary. An elliptic grid generator is employed to discretize the flow domain. In addition, an equilibrium air capability has been incorporated into the code. It uses the curve fits of Tannehill, et al. The flow regimes vary from a Mach number of 2 up to 25. Both laminar and turbulent flow are considered. Varying angles of attack have also been computed. Configurations vary from simple cone-type bodies to lifting winged bodies, such as the space shuttle or the generic supersonic cruise fighter.

  12. Abnormal uterine bleeding.

    PubMed

    Whitaker, Lucy; Critchley, Hilary O D

    2016-07-01

    Abnormal uterine bleeding (AUB) is a common and debilitating condition with high direct and indirect costs. AUB frequently co-exists with fibroids, but the relationship between the two remains incompletely understood and in many women the identification of fibroids may be incidental to a menstrual bleeding complaint. A structured approach for establishing the cause using the Fédération International de Gynécologie et d'Obstétrique (FIGO) PALM-COEIN (Polyp, Adenomyosis, Leiomyoma, Malignancy (and hyperplasia), Coagulopathy, Ovulatory disorders, Endometrial, Iatrogenic and Not otherwise classified) classification system will facilitate accurate diagnosis and inform treatment options. Office hysteroscopy and increasing sophisticated imaging will assist provision of robust evidence for the underlying cause. Increased availability of medical options has expanded the choice for women and many will no longer need to recourse to potentially complicated surgery. Treatment must remain individualised and encompass the impact of pressure symptoms, desire for retention of fertility and contraceptive needs, as well as address the management of AUB in order to achieve improved quality of life. PMID:26803558

  13. N95 and p100 respirator filter efficiency under high constant and cyclic flow.

    PubMed

    Eshbaugh, Jonathan P; Gardner, Paul D; Richardson, Aaron W; Hofacre, Kent C

    2009-01-01

    This study investigated the effect of high flow conditions on aerosol penetration and the relationship between penetration at constant and cyclic flow conditions. National Institute for Occupational Safety and Health (NIOSH)-approved N95 and P100 filtering facepiece respirators and cartridges were challenged with inert solid and oil aerosols. A combination of monodisperse aerosol and size-specific aerosol measurement equipment allowed count-based penetration measurement of particles with nominal diameters ranging from 0.02 to 2.9 microm. Three constant flow conditions (85, 270, and 360 L/min) were selected to match the minute, inhalation mean, and inhalation peak flows of the four cyclic flow conditions (40, 85, 115, and 135 L/min) tested. As expected, penetration was found to increase under increased constant and cyclic flow conditions. The most penetrating particle size (MPPS) generally ranged from 0.05 to 0.2 microm for P100 filters and was approximately 0.05 microm for N95 filters. Although penetration increased at the high flow conditions, the MPPS was relatively unaffected by flow. Of the constant flows tested, the flows equivalent to cyclic inhalation mean and peak flows best approximated the penetration measurements of the corresponding cyclic flows. PMID:19012163

  14. High resolution characterization of aquifers to improve flow and transport models of highly heterogeneous media

    NASA Astrophysics Data System (ADS)

    Dogan Diker, Mine

    Aquifers are the primary sources of clean drinking water. Pollution in aquifers is one of the most challenging and important environmental problems. It is not only extremely complex to map but also difficult to remediate. Flow and transport of water and pollutants in porous media requires detailed characterization of the properties of the media. The main property which controls the flow and transport is hydraulic conductivity (K), which can be defined as the ability of the media to let the water flow through. Intensive studies to map the distribution of hydraulic conductivity are necessary to model the plume migration. Conventional in-situ aquifer characterization techniques are invasive and lack the necessary high resolution. Therefore, novel methods are required to improve the methods to monitor and simulate the flow and transport through aquifers. This study introduces a combination of novel techniques to provide the necessary information related to porous media. The proposed method was tested at a highly heterogeneous site called the Macro Dispersion Experiment (MADE) site in Mississippi. The MADE site is a very well studied site where several large scale tracer tests were conducted in the 1980s and 1990s. The tracers used for these tests were monitored using more than 300 multi-level sampler (MLS) wells. Concentration measurements showed that the majority of the mass stayed near the injection area, whereas minute concentrations were measured further down-gradient. This behavior is significantly different from the simulations created using models based on the Advection-Dispersion Equation (ADE). This behavior and the inability to explain this using most models has led to a major debate in the hydrologic science community. The hypothesis of this study is that the ADE based models can reproduce simulations of the measured transport when the models are parameterized with sufficient high-resolution hydraulic conductivity data. Two novel high resolution

  15. High-Temperature Boc Deprotection in Flow and Its Application in Multistep Reaction Sequences.

    PubMed

    Bogdan, Andrew R; Charaschanya, Manwika; Dombrowski, Amanda W; Wang, Ying; Djuric, Stevan W

    2016-04-15

    A simplified Boc deprotection using a high-temperature flow reactor is described. The system afforded the qualitative yield of a wide variety of deprotected substrates within minutes using acetonitrile as the solvent and without the use of acidic conditions or additional workups. Highly efficient, multistep reaction sequences in flow are also demonstrated wherein no extraction or isolation was required between steps.

  16. High Flow Priapism in a Pediatric Patient after Circumcision with Dorsal Penile Nerve Block.

    PubMed

    Granieri, Michael A; Fantony, Joseph J; Routh, Jonathan C

    2016-01-01

    We report the first documented case of high flow priapism after circumcision with dorsal penile nerve block. A 7-year-old male who had undergone circumcision three years before presented to our institution with a 3-year history of persistent nonpainful erections. Workup revealed a high flow priapism and, after discussion of the management options, the patient's family elected continued observation. PMID:27648333

  17. High Flow Priapism in a Pediatric Patient after Circumcision with Dorsal Penile Nerve Block

    PubMed Central

    Fantony, Joseph J.; Routh, Jonathan C.

    2016-01-01

    We report the first documented case of high flow priapism after circumcision with dorsal penile nerve block. A 7-year-old male who had undergone circumcision three years before presented to our institution with a 3-year history of persistent nonpainful erections. Workup revealed a high flow priapism and, after discussion of the management options, the patient's family elected continued observation. PMID:27648333

  18. General purpose versus special algorithms for high-speed flows with shocks

    NASA Astrophysics Data System (ADS)

    Sai, B. V. K. Satya; Zienkiewicz, O. C.; Manzari, M. T.; Lyra, P. R. M.; Morgan, K.

    1998-01-01

    In this paper we compare the performance of a new general algorithm developed recently in application to problems of high Mach number flows with the performance of specialised algorithms applicable only to such flows. It appears that the results for most examples compare well, the biggest difference occurring in that of high Mach number compression corner.

  19. High Flow Priapism in a Pediatric Patient after Circumcision with Dorsal Penile Nerve Block

    PubMed Central

    Fantony, Joseph J.; Routh, Jonathan C.

    2016-01-01

    We report the first documented case of high flow priapism after circumcision with dorsal penile nerve block. A 7-year-old male who had undergone circumcision three years before presented to our institution with a 3-year history of persistent nonpainful erections. Workup revealed a high flow priapism and, after discussion of the management options, the patient's family elected continued observation.

  20. Posttraumatic High-Flow Priapism Treated byN-Butyl-Cyanoacrylate Embolization

    SciTech Connect

    Numan, Fueruzan; Cakirer, Sinan; Islak, Civan; Oabguet, Guenduez; Kadioabglu, Ates; Cayan, Selahittin; Tellaloabglu, Sedat

    1996-04-15

    A patient with high-flow priapism was treated by transcatheter embolization of a posttraumatic left cavernosal arteriovenous fistula using N-butyl-cyanoacrylate (NBCA), resulting in complete detumescence. Erectile function has been preserved during a 3-month follow-up. Only two patients with NBCA embolization for high-flow priapism have been reported previously.

  1. Nonintrusive fast response oxygen monitoring system for high temperature flows

    NASA Technical Reports Server (NTRS)

    Oh, Daniel B.; Stanton, Alan C.

    1993-01-01

    A new technique has been developed for nonintrusive in situ measurement of oxygen concentration, gas temperature, and flow velocity of the test media in hypersonic wind tunnels. It is based on absorption of near-infrared radiation from inexpensive GaAlAs laser diodes used in optoelectronics industry. It is designed for simultaneous measurements along multiple lines of sight accessed by fiber optics. Molecular oxygen concentration is measured from the magnitude of absorption signals; rotational gas temperature is measured from the intensity ratio of two oxygen absorption lines; and the flow velocity is measured from the Doppler shift of the absorption line positions. This report describes the results of an extensive series of tests of the prototype instrument in laboratory flames emphasizing assessment of the instruments capabilities for quantitative measurement of O2 concentration (mole fraction) and gas temperature.

  2. Detailed design of a quiet high flow fan

    NASA Technical Reports Server (NTRS)

    Soltau, J. D.; Orelup, M. J.; Beguhn, A. A.; Wiles, F. M.; Anderson, M. J.

    1977-01-01

    A single stage fan was designed to demonstrate the noise abatement properties of near-sonic inlet flow and long-chord stator vanes for the reduction of both upstream and downstream propagated fan source noise. It is designed to produce a pressure ratio of 1.653:1 with an adiabatic efficiency of 83.9%. The fan has a 508 mm inlet diameter with a hub/tip ratio of 0.426 and a design tip speed of 533.4 m/sec. The design inlet specific flow rate is 219.71 kg/sec sq m and there are 10 tandem stator vanes with a combined aspect ratio of 0.54.

  3. High flow, low mobile weight quick disconnect system

    NASA Technical Reports Server (NTRS)

    Smith, Ronn G. (Inventor); Nagy, Jr., Zoltan Frank (Inventor); Moszczienski, Joseph Roch (Inventor)

    2010-01-01

    A fluid coupling device and coupling system that may start and stop the flow of a fluid is disclosed. In some embodiments, first and second couplings are provided having an actuator coupled with each of the couplings. The couplings and actuators may be detachable to provide quick disconnect features and, in some embodiments, provide unitary actuation for the actuators of the coupling device to facilitate connection in mobile applications. Actuation may occur as the two couplings and actuators are engaged and disengaged and may occur by rotational actuation of the actuators. Rotational actuation can be provided to ensure flow through the coupling device, which in some embodiments may further provide an offset venturi feature. Upon disengagement, a compression element such as a compression spring can be provided to return the actuators to a closed position. Some embodiments further provide a seal external to the actuators and provided at incipient engagement of the couplings.

  4. Particle deposition in low-speed, high-turbulence flows

    NASA Astrophysics Data System (ADS)

    Reck, Mads; Larsen, Poul S.; Ullum, Ulrik

    The experimental and numerical study considers the concentration of airborne particulate contaminants, such as spores of spoilage fungi, and their deposition on a surface, in a Petri dish, and on a warm box-shaped product placed in a food-processing environment. Field measurements by standard, active and passive samplers provide typical values of airborne concentrations and specific deposition fluxes. Velocity and turbulence data from field studies are used as input in large eddy simulations of the process, and estimates of deposition fluxes are of the same order of magnitude as those deduced from field measurements. Particle deposition is shown to be associated with near-wall coherent structures. Flow reversal, simulated by impulsive start, is shown to give higher deposition rates than steady mean flows.

  5. F-14A aircraft high-speed flow simulations

    NASA Technical Reports Server (NTRS)

    Boppe, C. W.; Rosen, B. S.

    1985-01-01

    A model of the Grumman/Navy F-14A aircraft was developed for analyses using the NASA/Grumman Transonic Wing-Body Code. Computations were performed for isolated wing and wing fuselage glove arrangements to determine the extent of aerodynamic interference effects which propagate outward onto the main wing outer panel. Additional studies were conducted using the full potential analysis, FLO 22, to calibrate any inaccuracies that might accrue because of small disturbance code limitations. Comparisons indicate that the NASA/Grumman code provides excellent flow simulations for the range of wing sweep angles and flow conditions that will be of interest for the upcoming F-14 Variable Sweep Flight Transition Experiment.

  6. Paths for current flow in polycrystalline high temperature superconductors

    SciTech Connect

    Kroeger, D.M.; Goyal, A.; Specht, E.D.

    1995-12-01

    Determinations from x-ray and electron microdiffraction studies of the populations and geometrical arrangements of small angle grain boundaries in Bi-2223 and Bi-2212 conductors and Tl-1223 deposits suggest that current flow in these polycrystalline materials is percolative in character. Comparison of measured misorientation angle distributions to calculated distributions suggest that not only texture but also grain boundary energy is important in increasing the number of small angle grain boundaries.

  7. High speed inviscid compressible flow by the finite element method

    NASA Technical Reports Server (NTRS)

    Zienkiewicz, O. C.; Loehner, R.; Morgan, K.

    1984-01-01

    The finite element method and an explicit time stepping algorithm which is based on Taylor-Galerkin schemes with an appropriate artificial viscosity is combined with an automatic mesh refinement process which is designed to produce accurate steady state solutions to problems of inviscid compressible flow in two dimensions. The results of two test problems are included which demonstrate the excellent performance characteristics of the proposed procedures.

  8. A high performance magnetorheological valve with a meandering flow path

    NASA Astrophysics Data System (ADS)

    Imaduddin, Fitrian; Amri Mazlan, Saiful; Rahman, Mohd Azizi Abdul; Zamzuri, Hairi; Ubaidillah; Ichwan, Burhanuddin

    2014-06-01

    The huge developments in the field of magnetorheological (MR) fluid-based devices will have a great influence on the future of mechatronic applications due to the ease of interfacing between electronic controls and the mechanical components that they provide. Among various MR fluid-based devices, an MR valve would be particularly significant for the development of other devices, if it could be successfully achieved. One of the most challenging obstacles to MR valve development is the difficulty of achieving device miniaturization while, at the same time, improving the achievable performance. This study demonstrates a novel design for an MR valve, using the meandering flow path approach in order to increase the effective area so that the MR fluid can be regulated within a small-sized valve. The meandering flow path is formed by combining multiple annular, radial and orifice flow channels. In order to analyze the valve performance, a mathematical model of the proposed MR valve is derived and combined with numerical simulation using the finite element method, with the intention of predicting the achievable pressure drop that can be generated by the valve. The predicted MR valve performances are then experimentally evaluated using an oscillation-disturbed bypass hydraulic cylinder. The simulation results show that the proposed MR valve design could yield substantial pressure drop improvement, which is confirmed by the experiment.

  9. 3-D High-Lift Flow-Physics Experiment - Transition Measurements

    NASA Technical Reports Server (NTRS)

    McGinley, Catherine B.; Jenkins, Luther N.; Watson, Ralph D.; Bertelrud, Arild

    2005-01-01

    An analysis of the flow state on a trapezoidal wing model from the NASA 3-D High Lift Flow Physics Experiment is presented. The objective of the experiment was to characterize the flow over a non-proprietary semi-span three-element high-lift configuration to aid in assessing the state of the art in the computation of three-dimensional high-lift flows. Surface pressures and hot-film sensors are used to determine the flow conditions on the slat, main, and flap. The locations of the attachments lines and the values of the attachment line Reynolds number are estimated based on the model surface pressures. Data from the hot-films are used to determine if the flow is laminar, transitional, or turbulent by examining the hot-film time histories, statistics, and frequency spectra.

  10. Locally adapted traits maintained in the face of high gene flow.

    PubMed

    Fitzpatrick, S W; Gerberich, J C; Kronenberger, J A; Angeloni, L M; Funk, W C

    2015-01-01

    Gene flow between phenotypically divergent populations can disrupt local adaptation or, alternatively, may stimulate adaptive evolution by increasing genetic variation. We capitalised on historical Trinidadian guppy transplant experiments to test the phenotypic effects of increased gene flow caused by replicated introductions of adaptively divergent guppies, which were translocated from high- to low-predation environments. We sampled two native populations prior to the onset of gene flow, six historic introduction sites, introduction sources and multiple downstream points in each basin. Extensive gene flow from introductions occurred in all streams, yet adaptive phenotypic divergence across a gradient in predation level was maintained. Descendants of guppies from a high-predation source site showed high phenotypic similarity with native low-predation guppies in as few as ~12 generations after gene flow, likely through a combination of adaptive evolution and phenotypic plasticity. Our results demonstrate that locally adapted phenotypes can be maintained despite extensive gene flow from divergent populations. PMID:25363522

  11. Post-translationally Abnormal Collagens of Prolyl 3-Hydroxylase-2 Null Mice Offer a Pathobiological Mechanism for the High Myopia Linked to Human LEPREL1 Mutations*

    PubMed Central

    Hudson, David M.; Joeng, Kyu Sang; Werther, Rachel; Rajagopal, Abbhirami; Weis, MaryAnn; Lee, Brendan H.; Eyre, David R.

    2015-01-01

    Myopia, the leading cause of visual impairment worldwide, results from an increase in the axial length of the eyeball. Mutations in LEPREL1, the gene encoding prolyl 3-hydroxylase-2 (P3H2), have recently been identified in individuals with recessively inherited nonsyndromic severe myopia. P3H2 is a member of a family of genes that includes three isoenzymes of prolyl 3-hydroxylase (P3H), P3H1, P3H2, and P3H3. Fundamentally, it is understood that P3H1 is responsible for converting proline to 3-hydroxyproline. This limited additional knowledge also suggests that each isoenzyme has evolved different collagen sequence-preferred substrate specificities. In this study, differences in prolyl 3-hydroxylation were screened in eye tissues from P3h2-null (P3h2n/n) and wild-type mice to seek tissue-specific effects due the lack of P3H2 activity on post-translational collagen chemistry that could explain myopia. The mice were viable and had no gross musculoskeletal phenotypes. Tissues from sclera and cornea (type I collagen) and lens capsule (type IV collagen) were dissected from mouse eyes, and multiple sites of prolyl 3-hydroxylation were identified by mass spectrometry. The level of prolyl 3-hydroxylation at multiple substrate sites from type I collagen chains was high in sclera, similar to tendon. Almost every known site of prolyl 3-hydroxylation in types I and IV collagen from P3h2n/n mouse eye tissues was significantly under-hydroxylated compared with their wild-type littermates. We conclude that altered collagen prolyl 3-hydroxylation is caused by loss of P3H2. We hypothesize that this leads to structural abnormalities in multiple eye tissues, but particularly sclera, causing progressive myopia. PMID:25645914

  12. High prevalence of cardiovascular and respiratory abnormalities in advanced, intensively treated (transplanted) myeloma: The case for ‘late effects’ screening and preventive strategies

    PubMed Central

    Samuelson, Clare; O'Toole, Laurence; Boland, Elaine; Greenfield, Diana; Ezaydi, Yousef; Ahmedzai, Sam H.; Snowden, John A.

    2016-01-01

    Objectives: Modern management of myeloma has significantly improved survival, with increasing numbers of patients living beyond a decade. However, little is known about the long-term cardiovascular and respiratory status of intensively treated and multiply relapsed survivors. Methods: We performed detailed cardiovascular and respiratory evaluations in patients with intensively treated, advanced but stable myeloma. All patients had received at least two lines of treatment, including at least one haematopoietic stem cell transplantation procedure, but had stable, controlled disease and were off active treatment at the time of evaluation. Results: Thirty-two patients with a median duration of 6 years (range 2–12) from original diagnosis of myeloma and three lines (range 2–6) of treatment were evaluated. Despite normal physical examination in the majority, there was a high prevalence of sub-clinical cardiac and respiratory dysfunction, reflected by abnormalities of electrocardiography (45%), echocardiography (50%), serum N-terminal pro-B-type natriuretic peptide level (NT-pro-BNP, 50%), and pulmonary function testing (45%). NT-pro-BNP level correlated negatively with quality of life (P = 0.012) and positively with serum ferritin (P = 0.027). Dyspnoea score correlated with BMI (P = 0.001). Risk factors for cardiovascular disease (obesity, hypertension, hyperlipidaemia, and hyperinsulinaemia) were common. Discussion: Even in the absence of overt clinical features, the majority of intensively treated long-term survivors of myeloma have established cardiovascular and/or respiratory dysfunction, above levels expected in the general population of a similar age. Conclusion: This study supports routine screening and lifestyle modification combined with primary and secondary preventive strategies to reduce cardiovascular and respiratory disease and to preserve quality of life in transplanted myeloma patients. PMID:27077780

  13. Non-Darcian flow in low-permeability media: key issues related to geological disposal of high-level nuclear waste in shale formations

    NASA Astrophysics Data System (ADS)

    Liu, Hui-Hai

    2014-05-01

    In clay or other low-permeability media, water flow becomes non-Darcian and characterized by the non-linear relationship between water flux and hydraulic gradient. This work is devoted to addressing a number of key issues related to geological disposal of high-level nuclear waste in clay/shale formations. It is demonstrated that water flow velocity in the damaged zone (often considered as a potential preferential advection paths in a repository) surrounding the tunnel is extremely small, as a result of non-Darcian flow behavior, such that solute transport is dominated by diffusion, rather than advection. The finding is also consistent with the often-observed existence of persistent abnormal pressures in shale formations. While relative permeability is the key parameter for modeling the unsaturated flow process, without incorporating non-Darcian flow behavior, significant errors can occur in the determination of relative permeability values from traditional measurement methods. An approach for dealing with temperature impact on non-Darcian flow and a formulation to calculate non-Darcian water flux in an anisotropic medium are presented, taking into consideration that a geological repository is subject to temperature evolution in the near field as a result of heat generated by nuclear waste, and that shale formations are generally anisotropic.

  14. High-resolution Digital Mapping of Historical Lava Flows as a Test-bed for Lava Flow Models

    NASA Astrophysics Data System (ADS)

    Pyle, D. M.; Parks, M.; Nomikou, P.; Mather, T. A.; Simou, E.; Kalnins, L. M.; Paulatto, M.; Watts, A. B.

    2013-12-01

    Quantitative analysis of high-resolution lava flow morphology can improve our understanding of past effusive eruptions by providing insight into eruptive processes and the rheological properties of erupted magmas. We report the results of an ongoing investigation into the young dacite lava flows of the Kameni islands, Santorini volcano, Greece, which were emplaced during both subaerial and shallow submarine eruptions over the past 3000 years. Historical eruptions of the Kameni islands since 1866 have been very carefully documented in contemporaneous scientific reports. Eruptions since 1573 appear to be time-predictable, with a close relationship between eruption length, the size of extruded lava domes, and the time elapsed since the previous eruption. A new NERC - Airborne Survey and Research Facility LiDAR survey of the Kameni islands was completed in May 2012, using a Leica ALS50 Airborne Laser Scanner mounted on a Dornier 228 aircraft. The topographic surface was mapped at an average point density of 2.1 points per square metre, and covers the entire extent of the youngest subaerial lava flow fields on Santorini. A 2-m DEM derived from the 2012 LiDAR dataset was merged with a 5-m resolution bathymetric grid, based on multibeam surveys carried out by the Hellenic Centre for Marine Research, during cruises in 2001 and 2006, using a SEABEAM 2120 hull-mounted swath system. The resultant grid provides the first high resolution map of both subaerial and submarine historic lava flows emplaced in the centre of the Santorini caldera, and includes several previously unidentified submarine flows and cones. Attribute maps were used to delineate and identify discrete lava flows both onshore and offshore; and morphometric profiles were used to compute accurate volumetric estimates for each of the historic flows, and to determine bulk rheological properties of the lavas, assuming a Bingham rheology. This ongoing work will improve our analysis of the relationship between

  15. Genetic Counseling for a Prenatal Diagnosis of Structural Chromosomal Abnormality with High-Resolution Analysis Using a Single Nucleotide Polymorphism Microarray

    PubMed Central

    Takashima, Akiko; Takeshita, Naoki; Kinoshita, Toshihiko

    2016-01-01

    A 41-year old pregnant woman underwent amniocentesis to conduct a conventional karyotyping analysis; the analysis reported an abnormal karyotype: 46, XY, add(9)(p24). Chromosomal microarray analysis (CMA) is utilized in prenatal diagnoses. A single nucleotide polymorphism microarray revealed a male fetus with balanced chromosomal translocations on 9p and balanced chromosomal rearrangements, but another chromosomal abnormality was detected. The fetus had microduplication. The child was born as a phenotypically normal male. CMA is a simple and informative procedure for prenatal genetic diagnosis. CMA is the detection of chromosomal variants of unknown clinical significance; therefore, genetic counseling is important during prenatal genetic testing. PMID:27777709

  16. High-frequency, resonance-enhanced microactuators with active structures for high-speed flow control

    NASA Astrophysics Data System (ADS)

    Kreth, Phillip Andrew

    The need for actuators that are adaptable for use in a wide array of applications has been the motivation behind actuator development research over the past few years. Recent developments at the Advanced Aero-Propulsion Laboratory (AAPL) at Florida State University have produced a microactuator that uses the unsteadiness of a small-scale impinging jet to produce pulsed, supersonic microjets -- this is referred to as the Resonance-Enhanced Microjet (REM) actuator. Prior studies on these actuators at AAPL have been somewhat limited in that the actuator response has only been characterized through pressure/acoustic measurements and qualitative flow visualizations. Highly-magnified particle image velocimetry (PIV) measurements were performed to measure the velocity fields of both a 1 mm underexpanded jet and an REM actuator. The results demonstrate that this type of microactuator is capable of producing pulsed, supersonic microjets that have velocities of approximately 400 m/s that are sustained for significant portions of their cycles (> 60 %). These are the first direct velocity measurements of these flowfields, and they allow for a greater understanding of the flow physics associated with this microactuator. The previous studies on the REM actuators have shown that the microactuator volume is among the principal parameters in determining the actuator's maximum-amplitude frequency component. In order to use this actuator in a closed-loop, feedback control system, a modified design that incorporates smart materials is studied. The smart materials (specifically piezoelectric ceramic stack actuators) have been implemented into the microactuator to actively change its geometry, thus permitting controllable changes in the microactuator's resonant frequency. The distinct feature of this design is that the smart materials are not used to produce the primary perturbation or flow from the actuator (which has in the past limited the control authority of other designs) but to

  17. High-NaCl diet impairs dynamic renal blood flow autoregulation in rats with adenine-induced chronic renal failure.

    PubMed

    Saeed, Aso; DiBona, Gerald F; Grimberg, Elisabeth; Nguy, Lisa; Mikkelsen, Minne Line Nedergaard; Marcussen, Niels; Guron, Gregor

    2014-03-15

    This study examined the effects of 2 wk of high-NaCl diet on kidney function and dynamic renal blood flow autoregulation (RBFA) in rats with adenine-induced chronic renal failure (ACRF). Male Sprague-Dawley rats received either chow containing adenine or were pair-fed an identical diet without adenine (controls). After 10 wk, rats were randomized to either remain on the same diet (0.6% NaCl) or to be switched to high 4% NaCl chow. Two weeks after randomization, renal clearance experiments were performed under isoflurane anesthesia and dynamic RBFA, baroreflex sensitivity (BRS), systolic arterial pressure variability (SAPV), and heart rate variability were assessed by spectral analytical techniques. Rats with ACRF showed marked reductions in glomerular filtration rate and renal blood flow (RBF), whereas mean arterial pressure and SAPV were significantly elevated. In addition, spontaneous BRS was reduced by ∼50% in ACRF animals. High-NaCl diet significantly increased transfer function fractional gain values between arterial pressure and RBF in the frequency range of the myogenic response (0.06-0.09 Hz) only in ACRF animals (0.3 ± 4.0 vs. -4.4 ± 3.8 dB; P < 0.05). Similarly, a high-NaCl diet significantly increased SAPV in the low-frequency range only in ACRF animals. To conclude, a 2-wk period of a high-NaCl diet in ACRF rats significantly impaired dynamic RBFA in the frequency range of the myogenic response and increased SAPV in the low-frequency range. These abnormalities may increase the susceptibility to hypertensive end-organ injury and progressive renal failure by facilitating pressure transmission to the microvasculature.

  18. G6PD deficiency, absence of alpha-thalassemia, and hemolytic rate at baseline are significant independent risk factors for abnormally high cerebral velocities in patients with sickle cell anemia.

    PubMed

    Bernaudin, Françoise; Verlhac, Suzanne; Chevret, Sylvie; Torres, Martine; Coic, Lena; Arnaud, Cécile; Kamdem, Annie; Hau, Isabelle; Grazia Neonato, Maria; Delacourt, Christophe

    2008-11-15

    Stroke is predicted by abnormally high cerebral velocities by transcranial doppler (TCD). This study aimed at defining predictive factors for abnormally high velocities (>/= 2 m/sec) based on the Créteil pediatric sickle cell anemia (SCA) cohort composed of 373 stroke-free SCA children. alpha genes and beta-globin haplotypes were determined. Biologic parameters were obtained at baseline. alpha-thalassemia was present in 155 of 325 and G6PD deficiency in 36 of 325 evaluated patients. TCD was abnormal in 62 of 373 patients. Multivariate logistic regression analysis showed that G6PD deficiency (odds ratio [OR] = 3.36, 95% confidence interval [CI] 1.10-10.33; P = .034), absence of alpha-thalassemia (OR = 6.45, 95% CI 2.21-18.87; P = .001), hemoglobin (OR per g/dL = 0.63, 95% CI 0.41-0.97; P = .038), and lactate dehydrogenase (LDH) levels (OR per IU/L = 1.001, 95% CI 1.000-1.002; P = .047) were independent risk factors for abnormally high velocities. This study confirms the protective effect of alpha-thalassemia and shows for the first time that G6PD deficiency and hemolysis independently increase the risk of cerebral vasculopathy.

  19. CFD simulations of the flow control performance applied for inlet of low drag high-bypass turbofan engine at cross flow regimes

    NASA Astrophysics Data System (ADS)

    Kursakov, I. A.; Kazhan, E. V.; Lysenkov, A. V.; Savelyev, A. A.

    2016-10-01

    Paper describes the optimization procedure for low cruise drag inlet of high-bypass ratio turbofan engine (HBRE). The critical cross-flow velocity when the flow separation on the lee side of the inlet channel occurs is determined. The effciency of different flow control devices used to improve the flow parameters at inlet section cross flow regime is analyzed. Boundary layer suction, bypass slot and vortex generators are considered. It is shown that flow control devices enlarge the stability range of inlet performance at cross flow regimes.

  20. Determining the frequency, depth and velocity of preferential flow by high frequency soil moisture monitoring.

    PubMed

    Hardie, Marcus; Lisson, Shaun; Doyle, Richard; Cotching, William

    2013-01-01

    Preferential flow in agricultural soils has been demonstrated to result in agrochemical mobilisation to shallow ground water. Land managers and environmental regulators need simple cost effective techniques for identifying soil - land use combinations in which preferential flow occurs. Existing techniques for identifying preferential flow have a range of limitations including; often being destructive, non in situ, small sampling volumes, or are subject to artificial boundary conditions. This study demonstrated that high frequency soil moisture monitoring using a multi-sensory capacitance probe mounted within a vertically rammed access tube, was able to determine the occurrence, depth, and wetting front velocity of preferential flow events following rainfall. Occurrence of preferential flow was not related to either rainfall intensity or rainfall amount, rather preferential flow occurred when antecedent soil moisture content was below 226 mm soil moisture storage (0-70 cm). Results indicate that high temporal frequency soil moisture monitoring may be used to identify soil type - land use combinations in which the presence of preferential flow increases the risk of shallow groundwater contamination by rapid transport of agrochemicals through the soil profile. However use of high frequency based soil moisture monitoring to determine agrochemical mobilisation risk may be limited by, inability to determine the volume of preferential flow, difficulty observing macropore flow at high antecedent soil moisture content, and creation of artificial voids during installation of access tubes in stony soils. PMID:23159761

  1. Acute Portal Hypertension Models in Dogs: Low- and High-Flow Approaches

    PubMed Central

    Dave, Jaydev K; Liu, Ji-Bin; Halldorsdottir, Valgerdur G; Eisenbrey, John R; Merton, Daniel A; Machado, Priscilla; Zhao, Hongjia; Altemus, Joseph; Needleman, Laurence; Brown, Daniel B; Forsberg, Flemming

    2012-01-01

    Effective animal models are needed to evaluate the feasibility of new techniques to assess portal hypertension (PH). Here we developed 2 canine models of acute PH by increasing intrasinusoidal resistance and by increasing the portal vein (PV) flow volume to test the efficacy of a noninvasive technique to evaluate PH. The acute low-flow PH model was based on embolization of liver circulation by using a gelatin sponge material. The acute high-flow PH model was based on increasing the PV flow volume by using an arteriovenous (A-V) shunt from the femoral artery and saline infusion. PV pressures and diameters were assessed before and after inducing PH. Pressure values and diameters were obtained from the inferior vena cava in 3 unmanipulated controls. The low-flow model of PH was repeatable and successfully increased PV pressure by an average of 16.5 mm Hg within 15 min. The high-flow model of PH failed to achieve increased PV pressures. However, saline supplementation of the portal circulation in the high-flow model led to mean increases in PV pressures of 12.8 mm Hg within 20 min. Pulsatility in the PV was decreased in the low-flow model and increased in the high-flow model relative to baseline. No changes in PV diameter were noted in either model. These acute PH models are relatively straightforward to implement and may facilitate the evaluation of new techniques to assess PH. PMID:23114046

  2. Flow-Electrode Capacitive Deionization Using an Aqueous Electrolyte with a High Salt Concentration.

    PubMed

    Yang, SeungCheol; Choi, Jiyeon; Yeo, Jeong-Gu; Jeon, Sung-Il; Park, Hong-Ran; Kim, Dong Kook

    2016-06-01

    Flow-electrode capacitive deionization (FCDI) is novel capacitive deionization (CDI) technology that exhibits continuous deionization and a high desalting efficiency. A flow-electrode with high capacitance and low resistance is required for achieving an efficient FCDI system with low energy consumption. For developing high-performance flow-electrode, studies should be conducted considering porous materials, conductive additives, and electrolytes constituting the flow-electrode. Here, we evaluated the desalting performances of flow-electrodes with spherical activated carbon and aqueous electrolytes containing various concentrations of NaCl in the FCDI unit cell for confirming the effect of salt concentration on the electrolyte of a flow-electrode on desalting efficiency. We verified the necessity of a moderate amount of salt in the flow-electrode for compensating for the reduction in the performance of the flow-electrode, attributed to the resistance of water used as the electrolyte. Simultaneously, we confirmed the potential use of salt water with a high salt concentration, such as seawater, as an aqueous electrolyte for the flow-electrode. PMID:27162028

  3. Determining the frequency, depth and velocity of preferential flow by high frequency soil moisture monitoring.

    PubMed

    Hardie, Marcus; Lisson, Shaun; Doyle, Richard; Cotching, William

    2013-01-01

    Preferential flow in agricultural soils has been demonstrated to result in agrochemical mobilisation to shallow ground water. Land managers and environmental regulators need simple cost effective techniques for identifying soil - land use combinations in which preferential flow occurs. Existing techniques for identifying preferential flow have a range of limitations including; often being destructive, non in situ, small sampling volumes, or are subject to artificial boundary conditions. This study demonstrated that high frequency soil moisture monitoring using a multi-sensory capacitance probe mounted within a vertically rammed access tube, was able to determine the occurrence, depth, and wetting front velocity of preferential flow events following rainfall. Occurrence of preferential flow was not related to either rainfall intensity or rainfall amount, rather preferential flow occurred when antecedent soil moisture content was below 226 mm soil moisture storage (0-70 cm). Results indicate that high temporal frequency soil moisture monitoring may be used to identify soil type - land use combinations in which the presence of preferential flow increases the risk of shallow groundwater contamination by rapid transport of agrochemicals through the soil profile. However use of high frequency based soil moisture monitoring to determine agrochemical mobilisation risk may be limited by, inability to determine the volume of preferential flow, difficulty observing macropore flow at high antecedent soil moisture content, and creation of artificial voids during installation of access tubes in stony soils.

  4. Numerical Simulations of High-Speed Chemically Reacting Flow

    NASA Technical Reports Server (NTRS)

    Ton, V. T.; Karagozian, A. R.; Marble, F. E.; Osher, S. J.; Engquist, B. E.

    1994-01-01

    The essentially nonoscillatory (ENO) shock-capturing scheme for the solution of hyperbolic equations is extended to solve a system of coupled conservation equations governing two-dimensional, time-dependent, compressible chemically reacting flow with full chemistry. The thermodynamic properties of the mixture are modeled accurately, and stiff kinetic terms are separated from the fluid motion by a fractional step algorithm. The methodology is used to study the concept of shock-induced mixing and combustion, a process by which the interaction of a shock wave with a jet of low-density hydrogen fuel enhances mixing through streamwise vorticity generation. Test cases with and without chemical reaction are explored here. Our results indicate that, in the temperature range examined, vorticity generation as well as the distribution of atomic species do not change significantly with the introduction of a chemical reaction and subsequent heat release. The actual diffusion of hydrogen is also relatively unaffected by the reaction process. This suggests that the fluid mechanics of this problem may be successfully decoupled from the combustion processes, and that computation of the mixing problem (without combustion chemistry) can elucidate much of the important physical features of the flow.

  5. Numerical Simulations of High-Speed Chemically Reacting Flow

    NASA Technical Reports Server (NTRS)

    Ton, V. T.; Karagozin, A. R.; Marble, F. E.; Osher, S. J.; Engquist, B. E.

    1994-01-01

    The Essentially NonOscillatory (ENO) shock-capturing scheme for the solution of hyperbolic equations is extended to solve a system of coupled conservation equations governing two-dimensional, time-dependent, compressible chemically reacting flow with full chemistry. The thermodynamic properties of the mixture are modeled accurately, and stiff kinetic terms are separated from the fluid motion by a fractional step algorithm. The methodology is used to study the concept of shock-induced mixing and combustion, a process by which the interaction of a shock wave with a jet of low-density hydrogen fuel enhances mixing through streamwise vorticity generation. Test cases with and without chemical reaction are explored here. Our results indicate that, in the temperature range examined, vorticity generation as well as the distribution of atomic species do not change significantly with the introduction of a chemical reaction and subsequent heat release. The actual diffusion of hydrogen is also relatively unaffected by the reaction process. This suggests that the fluid mechanics of this problem may be successfully decoupled from the combustion processes, and that computation of the mixing problem (without combustion chemistry) can elucidate much of the important physical features of the flow.

  6. Multiscale Modeling of Particles Embedded in High Speed Flows

    NASA Astrophysics Data System (ADS)

    Davis, Sean; Sen, Oishik; Jacobs, Gustaaf; Udaykumar, H. S.

    2015-06-01

    Problems involving propagation of shock waves through a cloud of particles are inherently multiscale. The system scale is governed by macro-scale conservation equations, which average over solid and fluid phases. The averaging process results in source terms that represent the unresolved momentum exchange between the solid phase and the fluid phase. Typically, such source terms are modeled using empirical correlations derived from physical experiments conducted in a limited parameter space. The focus of the current research is to advance the multiscale modeling of shocked particle-laden gas flows; particle- (i.e. meso-)scale computations are performed to resolve the dynamics of ensembles of particles and closure laws are obtained from the meso-scale for use in the macro-scale equations. Closure models are constructed from meso-scale simulations using the Dynamic Kriging method. The presentation will demonstrate the multiscale approach by connecting meso-scale simulations to an Eulerian-Lagrangian macro-scale model of particle laden flows. The technique is applied to study shock interactions with particle curtains in shock tubes and the results are compared with experimental data in such systems. We gratefully acknowledge the financial support by the Air Force Office of Scientific Research under Grant Number FA9550-12-1-0115 and the National Science Foundation under grant number DMS-115631.

  7. Thermal and pressure diffusion effects in high altitude flows

    NASA Technical Reports Server (NTRS)

    Bird, G. A.

    1988-01-01

    An apparently anomalous change in composition adjacent to a non-catalytic surface in an earlier DSMC calculation of a non-reacting gas mixture is shown to have been due to thermal diffusion. Both thermal and pressure diffusion can lead to species separation effects in the flow of gas mixtures, but are not generally included in Navier-Stokes formulations. Additional DSMC calculations are made for blunt-body and plume expansion flows using both a simple gas and an otherwise identical gas mixture. These test calculations indicate that the pressure distribution on the forward face of a blunt body is largely unaffected by the species separation in the stagnation region. The gas density in this region is significantly affected and there is a slight change in the heat transfer to the surface. The pressure distribution around the shoulder of the body is affected. Very large separations occur in the plume expansion of the gas mixtures and there is an order of magnitude increase in density in the backflow region for the mixture.

  8. Interpretation of high-speed flows in the plasma sheet

    NASA Technical Reports Server (NTRS)

    Chen, C. X.; Wolf, R. A.

    1993-01-01

    Pursuing an idea suggested by Pontius and Wolf (1990), we propose that the `bursty bulk flows' observed by Baumjohann et al. (1990) and Angelopoulos et al. (1992) are `bubbles' in the Earth's plasma sheet. Specifically, they are flux tubes that have lower values of pV(exp 5/3) than their neighbors, where p is the thermal pressure of the particles and V is the volume of a tube containing one unit of magnetic flux. Whether they are created by reconnection or some other mechanism, the bubbles are propelled earthward by a magnetic buoyancy force, which is related to the interchange instability. Most of the major observed characteristics of the bursty bulk flows can be interpreted naturally in terms of the bubble picture. We propose a new `stratified fluid' picture of the plasma sheet, based on the idea that bubbles constitute the crucial transport mechanism. Results from simple mathematical models of plasma sheet transport support the idea that bubbles can resolve the pressure balance inconsistency, particularly in cases where plasma sheet ions are lost by gradient/curvature drift out the sides of the tail or bubbles are generated by reconnection in the middle of plasma sheet.

  9. Low temperature high current ion beams and laminar flows

    NASA Astrophysics Data System (ADS)

    Cavenago, Marco

    2014-07-01

    Self-consistent Vlasov-Poisson equilibria for the extraction of ions with low temperature Ti are discussed, with comparison to the laminar flow case Ti = 0, in two dimensional diodes. Curvilinear coordinates aligned with laminar beam flow lines are extended to the low ion temperature case, with a reduced current density jd, expressed with cathode integrals. This generalizes one-dimensional interpolation between rays along the cathode coordinate to multidimensional integrations, including also the momentum components, so that jd is free from the granularity defect and noise, typical of standard ray tracing approach. A robust numerical solution procedure is developed, which allows studying current saturated extraction and drift tube effects. A discussion of particle initial conditions determines the emission angles and shows that temperature effect at beam edge is partly balanced by the focus electrode inclination. Results for a typical diode are described, with detail about normalized emittance, here taken strictly proportional to the x - px phase space area, for a beam with non uniform velocities. Contribution to the Topical Issue "Theory and Applications of the Vlasov Equation", edited by Francesco Pegoraro, Francesco Califano, Giovanni Manfredi and Philip J. Morrison.

  10. [Hair shaft abnormalities].

    PubMed

    Itin, P H; Düggelin, M

    2002-05-01

    Hair shaft disorders may lead to brittleness and uncombable hair. In general the hair feels dry and lusterless. Hair shaft abnormalities may occur as localized or generalized disorders. Genetic predisposition or exogenous factors are able to produce and maintain hair shaft abnormalities. In addition to an extensive history and physical examination the most important diagnostic examination to analyze a hair shaft problem is light microscopy. Therapy of hair shaft disorders should focus to the cause. In addition, minimizing traumatic influences to hair shafts, such as dry hair with an electric dryer, permanent waves and dyes is important. A short hair style is more suitable for such patients with hair shaft disorders.

  11. The numerical simulation of a high-speed axial flow compressor

    NASA Technical Reports Server (NTRS)

    Mulac, Richard A.; Adamczyk, John J.

    1991-01-01

    The advancement of high-speed axial-flow multistage compressors is impeded by a lack of detailed flow-field information. Recent development in compressor flow modeling and numerical simulation have the potential to provide needed information in a timely manner. The development of a computer program is described to solve the viscous form of the average-passage equation system for multistage turbomachinery. Programming issues such as in-core versus out-of-core data storage and CPU utilization (parallelization, vectorization, and chaining) are addressed. Code performance is evaluated through the simulation of the first four stages of a five-stage, high-speed, axial-flow compressor. The second part addresses the flow physics which can be obtained from the numerical simulation. In particular, an examination of the endwall flow structure is made, and its impact on blockage distribution assessed.

  12. Numerical dissipation control in high order shock-capturing schemes for LES of low speed flows

    NASA Astrophysics Data System (ADS)

    Kotov, D. V.; Yee, H. C.; Wray, A. A.; Sjögreen, B.; Kritsuk, A. G.

    2016-02-01

    The Yee & Sjögreen adaptive numerical dissipation control in high order scheme (High Order Filter Methods for Wide Range of Compressible Flow Speeds, ICOSAHOM 09, 2009) is further improved for DNS and LES of shock-free turbulence and low speed turbulence with shocklets. There are vastly different requirements in the minimization of numerical dissipation for accurate turbulence simulations of different compressible flow types and flow speeds. Traditionally, the method of choice for shock-free turbulence and low speed turbulence are by spectral, high order central or high order compact schemes with high order linear filters. With a proper control of a local flow sensor, appropriate amount of numerical dissipation in high order shock-capturing schemes can have spectral-like accuracy for compressible low speed turbulent flows. The development of the method includes an adaptive flow sensor with automatic selection on the amount of numerical dissipation needed at each flow location for more accurate DNS and LES simulations with less tuning of parameters for flows with a wide range of flow speed regime during the time-accurate evolution, e.g., time varying random forcing. An automatic selection of the different flow sensors catered to the different flow types is constructed. A Mach curve and high-frequency oscillation indicators are used to reduce the tuning of parameters in controlling the amount of shock-capturing numerical dissipation to be employed for shock-free turbulence, low speed turbulence and turbulence with strong shocks. In Kotov et al. (High Order Numerical Methods for LES of Turbulent Flows with Shocks, ICCFD8, Chengdu, Sichuan, China, July 14-18, 2014) the LES of a turbulent flow with a strong shock by the Yee & Sjögreen scheme indicated a good agreement with the filtered DNS data. A work in progress for the application of the adaptive flow sensor for compressible turbulence with time-varying random forcing is forthcoming. The present study examines the

  13. High-speed visualization of disturbed pathlines in axial flow ventricular assist device under pulsatile conditions

    PubMed Central

    Yang, Fang; Kormos, Robert L.; Antaki, James F.

    2015-01-01

    Objective: To investigate potentially pro-thrombotic flow patterns within an axial flow ventricular assist device under clinically relevant pulsatile hemodynamic conditions. Methods A transparent replica of the HeartMate-II was visualized using a high speed camera at both low and high frame rates (125 and 3000 fps). Three steady-state conditions were studied: nominal (4.5 lpm), low flow (3.0 lpm) and high flow (6.0 lpm). Time-varying conditions were introduced with external pulsatile pump which modulated the flow rate by approximately +/−50% of the mean, corresponding to a pulsatility index of 1.0. Results At nominal and high flow rates, the path lines within the upstream region were generally stable, well attached, and streamlined. As the flow rate was reduced below 3.8 lpm, a rapid transition to a chaotic velocity field occurred exhibiting a large toroidal vortex adjacent to the upstream bearing. The pathlines in the downstream stator section were consistently chaotic for all hemodynamic conditions investigated. It was common to observe tracer particles trapped within recirculation bubbles and drawn retrograde, causing repeated contact with the bearing surfaces. The addition of pulsatility caused the flow field to become periodically chaotic during the diastolic portion of the cardiac cycle depending on the instantaneous flow rate and acceleration. Conclusion The contribution of pulsatility by the native heart may induce a periodic disturbance to an otherwise stable flow field within an axial flow VAD, particularly during the diastolic and decelerating portion of the cardiac cycle. Potentially pro-thrombotic flow features were found to occur periodically in the region of the upstream bearing. PMID:26208892

  14. Navier-Stokes flow field analysis of compressible flow in a high pressure safety relief valve

    NASA Astrophysics Data System (ADS)

    Vu, Bruce; Wang, Ten-See; Shih, Ming-Hsin; Soni, Bharat

    1993-12-01

    The objective of this study is to investigate the complex three-dimensional flowfield of an oxygen safety pressure relieve valve during an incident, with a computational fluid dynamic (CFD) analysis. Specifically, the analysis will provide a flow pattern that would lead to the expansion of the eventual erosion pattern of the hardware, so as to combine it with other findings to piece together a most likely scenario for the investigation. The CFD model is a pressure based solver. An adaptive upwind difference scheme is employed for the spatial discretization, and a predictor, multiple corrector method is used for the velocity-pressure coupling. The computational result indicated vortices formation near the opening of the valve which matched the erosion pattern of the damaged hardware.

  15. Navier-Stokes flow field analysis of compressible flow in a high pressure safety relief valve

    NASA Technical Reports Server (NTRS)

    Vu, Bruce; Wang, Ten-See; Shih, Ming-Hsin; Soni, Bharat

    1993-01-01

    The objective of this study is to investigate the complex three-dimensional flowfield of an oxygen safety pressure relieve valve during an incident, with a computational fluid dynamic (CFD) analysis. Specifically, the analysis will provide a flow pattern that would lead to the expansion of the eventual erosion pattern of the hardware, so as to combine it with other findings to piece together a most likely scenario for the investigation. The CFD model is a pressure based solver. An adaptive upwind difference scheme is employed for the spatial discretization, and a predictor, multiple corrector method is used for the velocity-pressure coupling. The computational result indicated vortices formation near the opening of the valve which matched the erosion pattern of the damaged hardware.

  16. Non-darcy flow behavior mean high-flux injection wells in porous and fractured formations

    SciTech Connect

    Wu, Yu-Shu

    2003-04-25

    This paper presents a study of non-Darcy fluid flow through porous and fractured rock, which may occur near wells during high-flux injection of waste fluids into underground formations. Both numerical and analytical models are used in this study. General non-Darcy flow is described using the Forchheimer equation, implemented in a three-dimensional, multiphase flow reservoir simulator. The non-Darcy flow through a fractured reservoir is handled using a general dual continuum approach, covering commonly used conceptual models, such as double porosity, dual permeability, explicit fracture, etc. Under single-phase flow conditions, an approximate analytical solution, as an extension of the Warren-Root solution, is discussed. The objectives of this study are (1) to obtain insights into the effect of non-Darcy flow on transient pressure behavior through porous and fractured reservoirs and (2) to provide type curves for well test analyses of non-Darcy flow wells. The type curves generated include various types of drawdown, injection, and buildup tests with non-Darcy flow occurring in porous and fractured reservoirs. In addition, non-Darcy flow into partially penetrating wells is also considered. The transient-pressure type curves for flow in fractured reservoirs are based on the double-porosity model. Type curves provided in this work for non-Darcy flow in porous and fractured reservoirs will find their applications in well test interpretation using a type-curve matching technique.

  17. Universal intermittent properties of particle trajectories in highly turbulent flows.

    PubMed

    Arnèodo, A; Benzi, R; Berg, J; Biferale, L; Bodenschatz, E; Busse, A; Calzavarini, E; Castaing, B; Cencini, M; Chevillard, L; Fisher, R T; Grauer, R; Homann, H; Lamb, D; Lanotte, A S; Lévèque, E; Lüthi, B; Mann, J; Mordant, N; Müller, W-C; Ott, S; Ouellette, N T; Pinton, J-F; Pope, S B; Roux, S G; Toschi, F; Xu, H; Yeung, P K

    2008-06-27

    We present a collection of eight data sets from state-of-the-art experiments and numerical simulations on turbulent velocity statistics along particle trajectories obtained in different flows with Reynolds numbers in the range R{lambda}in[120:740]. Lagrangian structure functions from all data sets are found to collapse onto each other on a wide range of time lags, pointing towards the existence of a universal behavior, within present statistical convergence, and calling for a unified theoretical description. Parisi-Frisch multifractal theory, suitably extended to the dissipative scales and to the Lagrangian domain, is found to capture the intermittency of velocity statistics over the whole three decades of temporal scales investigated here.

  18. An experimental study of highly transient squeeze-film flows

    NASA Astrophysics Data System (ADS)

    Krassnokutski, A.; Moss, E. A.; Skews, B. W.

    2013-06-01

    The aim of this work was to extend a previous investigation of the flow between two parallel disks (one of which was stationary) that have been subjected to a constant energy impact arising from a falling mass onto the upper disk assembly. Whereas the previous work considered the measurement of centreline pressures and distance between the plates only, for a single case, the current work in addition entailed monitoring of pressures at 45% and 90% of disk radius, under 28 combinations of drop height (100 to 1000 mm), drop mass (10 to 55 kg), and initial disk separation (3 to 10 mm), each with 5 repeat tests. Over the duration of the phenomenon (about 3.5 to 10 ms), four basic features were identified: (1) during initial impact under the dominance of temporal inertia, a preliminary pressure spike with peak pressures occurring at a displacement change of less than 0.25 mm from the initial disk separation; (2) an intermediate region with lower pressures; (3) pressure changes arising from a succession of elastic momentum exchanges (bounces) between the colliding masses; and (4) the final largest pressure spike towards the end of the phenomenon, where viscous effects dominate. Regions (1) and (4) became merged for smaller values of initial disk separation, with region (2) being obscured. A previously developed quasi-steady linear (QSL) model conformed satisfactorily with pressures measured at the centre of the lower disk; however, substantial deviations from radially parabolic pressure distributions were encountered over a range of operating parameters during the preliminary pressure phenomenon, unexpected because they implicitly conflict with the generally accepted concept of parallel flows and radially self-similar velocity profiles in such systems. Measurements of maximum pressures encountered during the preliminary and final pressure events agreed satisfactorily, both with the QSL model and with a simple but effective scaling analysis.

  19. TEMPO-based catholyte for high-energy density nonaqueous redox flow batteries.

    PubMed

    Wei, Xiaoliang; Xu, Wu; Vijayakumar, Murugesan; Cosimbescu, Lelia; Liu, Tianbiao; Sprenkle, Vincent; Wang, Wei

    2014-12-01

    A TEMPO-based non-aqueous electrolyte with the TEMPO concentration as high as 2.0 m is demonstrated as a high-energy-density catholyte for redox flow battery applications. With a hybrid anode, Li|TEMPO flow cells using this electrolyte deliver an energy efficiency of ca. 70% and an impressively high energy density of 126 W h L(-1) . PMID:25327755

  20. Hepatic perfusion abnormalities during CT angiography: Detection and interpretation

    SciTech Connect

    Freeny, P.C.; Marks, W.M.

    1986-06-01

    Twenty-seven perfusion abnormalities were detected in 17 of 50 patients who underwent computed tomographic angiography (CTA) of the liver. All but one of the perfusion abnormalities occurred in patients with primary or metastatic liver tumors. Perfusion abnormalities were lobar in nine cases, segmental in 11, and subsegmental in seven; 14 were hypoperfusion and 13 were hyperperfusion abnormalities. The causes for the abnormalities included nonperfusion of a replaced hepatic artery (n = 11), cirrhosis and nodular regeneration (n = 3), altered hepatic hemodynamics (e.g., siphoning, laminar flow) caused by tumor (n = 7), contrast media washout from a nonperfused vessel (n = 1), compression of adjacent hepatic parenchyma (n = 1), and unknown (n = 4). Differentiation of perfusion abnormalities from tumor usually can be made by comparing the morphology of the known tumor with the suspected perfusion abnormality, changes of each on delayed CTA scans, and review of initial angiograms and other imaging studies.

  1. Use of high-resolution upwind scheme for vortical flow simulations

    NASA Technical Reports Server (NTRS)

    Fujii, Kozo; Obayashi, Shigeru

    1988-01-01

    For vortical flow simulations at high Reynolds numbers, it is important to keep the artificial dissipation as small as possible since it induces unphysical decay of the vortex strength. One way to accomplish this is to decrease the grid spacing. Another way is to use computational schemes having little dissipation. Here, one of the high-resolution upwind schemes called MUSCL with Roe's average is applied to vortical flow fields. Two examples are considered. One is the leading-edge separation-vortex flow over a strake-delta wing. The other is a high-angle of attack supersonic flow over a spaceplane-like geometry. Comparison with the central difference solutions indicates that the present upwind scheme is less dissipative and thus has better resolution for the vortical flows.

  2. High Fidelity Simulations for Unsteady Flow Through the Orbiter LH2 Feedline Flowliner

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin C.; Kwak, Dochan; Chan, William; Housman, Jeffrey

    2005-01-01

    High fidelity computations were carried out to analyze the orbiter M2 feedline flowliner. Various computational models were used to characterize the unsteady flow features in the turbopump, including the orbiter Low-Pressure-Fuel-Turbopump (LPFTP) inducer, the orbiter manifold and a test article used to represent the manifold. Unsteady flow originating from the orbiter LPFTP inducer is one of the major contributors to the high frequency cyclic loading that results in high cycle fatigue damage to the gimbal flowliners just upstream of the LPFTP. The flow fields for the orbiter manifold and representative test article are computed and analyzed for similarities and differences. An incompressible Navier-Stokes flow solver INS3D, based on the artificial compressibility method, was used to compute the flow of liquid hydrogen in each test article.

  3. Flow Control Research at NASA Langley in Support of High-Lift Augmentation

    NASA Technical Reports Server (NTRS)

    Sellers, William L., III; Jones, Gregory S.; Moore, Mark D.

    2002-01-01

    The paper describes the efforts at NASA Langley to apply active and passive flow control techniques for improved high-lift systems, and advanced vehicle concepts utilizing powered high-lift techniques. The development of simplified high-lift systems utilizing active flow control is shown to provide significant weight and drag reduction benefits based on system studies. Active flow control that focuses on separation, and the development of advanced circulation control wings (CCW) utilizing unsteady excitation techniques will be discussed. The advanced CCW airfoils can provide multifunctional controls throughout the flight envelope. Computational and experimental data are shown to illustrate the benefits and issues with implementation of the technology.

  4. TanDEM-X high resolution DEMs and their applications to flow modeling

    NASA Astrophysics Data System (ADS)

    Wooten, Kelly M.

    Lava flow modeling can be a powerful tool in hazard assessments; however, the ability to produce accurate models is usually limited by a lack of high resolution, up-to-date Digital Elevation Models (DEMs). This is especially obvious in places such as Kilauea Volcano (Hawaii), where active lava flows frequently alter the terrain. In this study, we use a new technique to create high resolution DEMs on Kilauea using synthetic aperture radar (SAR) data from the TanDEM-X (TDX) satellite. We convert raw TDX SAR data into a geocoded DEM using GAMMA software [Werner et al., 2000]. This process can be completed in several hours and permits creation of updated DEMs as soon as new TDX data are available. To test the DEMs, we use the Harris and Rowland [2001] FLOWGO lava flow model combined with the Favalli et al. [2005] DOWNFLOW model to simulate the 3-15 August 2011 eruption on Kilauea's East Rift Zone. Results were compared with simulations using the older, lower resolution 2000 SRTM DEM of Hawaii. Effusion rates used in the model are derived from MODIS thermal infrared satellite imagery. FLOWGO simulations using the TDX DEM produced a single flow line that matched the August 2011 flow almost perfectly, but could not recreate the entire flow field due to the relatively high DEM noise level. The issues with short model flow lengths can be resolved by filtering noise from the DEM. Model simulations using the outdated SRTM DEM produced a flow field that followed a different trajectory to that observed. Numerous lava flows have been emplaced at Kilauea since the creation of the SRTM DEM, leading the model to project flow lines in areas that have since been covered by fresh lava flows. These results show that DEMs can quickly become outdated on active volcanoes, but our new technique offers the potential to produce accurate, updated DEMs for modeling lava flow hazards.

  5. Blood Flow in Arteries

    NASA Astrophysics Data System (ADS)

    Ku, David N.

    Blood flow in arteries is dominated by unsteady flow phenomena. The cardiovascular system is an internal flow loop with multiple branches in which a complex liquid circulates. A nondimensional frequency parameter, the Womersley number, governs the relationship between the unsteady and viscous forces. Normal arterial flow is laminar with secondary flows generated at curves and branches. The arteries are living organs that can adapt to and change with the varying hemodynamic conditions. In certain circumstances, unusual hemodynamic conditions create an abnormal biological response. Velocity profile skewing can create pockets in which the direction of the wall shear stress oscillates. Atherosclerotic disease tends to be localized in these sites and results in a narrowing of the artery lumena stenosis. The stenosis can cause turbulence and reduce flow by means of viscous head losses and flow choking. Very high shear stresses near the throat of the stenosis can activate platelets and thereby induce thrombosis, which can totally block blood flow to the heart or brain. Detection and quantification of stenosis serve as the basis for surgical intervention. In the future, the study of arterial blood flow will lead to the prediction of individual hemodynamic flows in any patient, the development of diagnostic tools to quantify disease, and the design of devices that mimic or alter blood flow. This field is rich with challenging problems in fluid mechanics involving three-dimensional, pulsatile flows at the edge of turbulence.

  6. Analysis of electrode system for generation of high-power electrodynamic flow

    NASA Astrophysics Data System (ADS)

    Rebrov, I. E.; Khomich, V. Yu.; Yamshchikov, V. A.

    2016-08-01

    A high-power electrodynamic flow in atmospheric air is numerically simulated and experimentally studied. An electrode system consisting of a cylindrical plasma emitter and a plane metal grid collector of ions is used to generate a flow with a speed of 2 m/s and a volume rate of 15 L/s.

  7. Porcine Vitreous Flow Behavior During High-Speed Vitrectomy up to 7500 Cuts per Minute

    PubMed Central

    Abulon, Dina Joy K.; Buboltz, David C.

    2016-01-01

    Purpose To evaluate the impact of high-speed cut rates (up to 7500 cuts per minute [cpm]) on vitreous flow through various gauge probes. Methods An open-sky vitrectomy technique was performed on porcine eyes using the CONSTELLATION Vision System with three different gauges of dual-pneumatic probes (27+-, 25+-, and 23-gauge UltraVit probes; n = 5 for each gauge). Flow rate was calculated by LabVIEW software that converted real-time mass measurements from an electronic scale into flow rate. Results Average vitreous flow rate increased slightly with increased cut rate in all probes with 50/50 duty cycle; more dramatic flow rate increases were observed for all probes with biased closed duty cycle. Under both conditions, maximum flow rate was observed at 7500 cpm for all gauges. Under the biased open duty cycle, average flow rate was inversely associated with cut rate. Conclusion High-speed cut rate improved efficiency of vitreous aspiration. Translational Relevance Increased vitreous aspiration of dual-pneumatic, high-speed vitrectomy probes may improve the efficiency of current vitrectomy techniques, allowing surgeons to take advantage of the benefits of high cut rates without sacrificing flow rate. PMID:26933520

  8. Effects of Aspect Ratio on Air Flow at High Subsonic Mach Numbers

    NASA Technical Reports Server (NTRS)

    Lindsey, W F; Humphreys, Milton D

    1952-01-01

    Schlieren photographs were used in an investigation to determine the effects of changing the aspect ratio from infinity to 2 on the air flow past a wing at high subsonic Mach numbers. The results indicated that the decreased effects of compressibility on drag coefficients for the finite wing are produced by a reduction in the compression shock and flow separation.

  9. Medical management of abnormal pregnancy.

    PubMed

    Ratnam, S S; Prasad, R N

    1990-06-01

    Medical termination of abnormal pregnancy requires specific techniques since some conditions make therapy more effective, e.g., missed abortion intrauterine death and molar pregnancy, and others less so, e.g. anencephalic pregnancy. In all cases it is best to terminate the pregnancy as soon as possible to reduce anguish and risks of complications such as consumptive coagulopathy. Oxytocin is not consistently effective, but intraamniotic rivanol has oxytocic properties, and prostaglandins (PGs) are effective by several routes. Surgical methods are more popular in Japan and the US. A diagnostic flow chart is included and described. For missed abortion and fetal death vacuum aspiration or dilatation and evacuation are appropriate for early pregnancy, or PGs are used for later pregnancy, unless there are medical contraindications. Anencephalic pregnancy, usually diagnoses in 2nd or 3rd trimester, is resistant to medical therapy and must often be terminated by cesarean section. Molar pregnancy can be managed with vacuum aspiration at any length of gestation, but must be completed by curettage. Intraamniotic PGs are not advised for mole or fetal death. PG analogs can be administered intramuscularly, or vaginally in gel form. Other types of abnormal pregnancy that can be managed with PGs are spina bifida, hydrocephalus, hydrops fetalis, Dandy-Walker syndrome and Down's syndrome. Tubal pregnancy can be evacuated with intratubally administered PGs under laparoscopic control, thereby preserving tubal integrity. PMID:2225605

  10. Use of a Novel High-Resolution Magnetic Resonance Neurography Protocol to Detect Abnormal Dorsal Root Ganglia in Sjögren Patients With Neuropathic Pain

    PubMed Central

    Birnbaum, Julius; Duncan, Trisha; Owoyemi, Kristie; Wang, Kenneth C.; Carrino, John; Chhabra, Avneesh

    2014-01-01

    Abstract The diagnosis and treatment of patients with Sjögren syndrome (SS) with neuropathic pain pose several challenges. Patients with SS may experience unorthodox patterns of burning pain not conforming to a traditional “stocking-and-glove” distribution, which can affect the face, torso, and proximal extremities. This distribution of neuropathic pain may reflect mechanisms targeting the proximal-most element of the peripheral nervous system—the dorsal root ganglia (DRG). Skin biopsy can diagnose such a small-fiber neuropathy and is a surrogate marker of DRG neuronal cell loss. However, SS patients have been reported who have similar patterns of proximal neuropathic pain, despite having normal skin biopsy studies. In such cases, DRGs may be targeted by mechanisms not associated with neuronal cell loss. Therefore, alternative approaches are warranted to help characterize abnormal DRGs in SS patients with proximal neuropathic pain. We performed a systematic review of the literature to define the frequency and spectrum of SS peripheral neuropathies, and to better understand the attribution of SS neuropathic pain to peripheral neuropathies. We found that the frequency of SS neuropathic pain exceeded the prevalence of peripheral neuropathies, and that painful peripheral neuropathies occurred less frequently than neuropathies not always associated with pain. We developed a novel magnetic resonance neurography (MRN) protocol to evaluate DRG abnormalities. Ten SS patients with proximal neuropathic pain were evaluated by this MRN protocol, as well as by punch skin biopsies evaluating for intraepidermal nerve fiber density (IENFD) of unmyelinated nerves. Five patients had radiographic evidence of DRG abnormalities. Patients with MRN DRG abnormalities had increased IENFD of unmyelinated nerves compared to patients without MRN DRG abnormalities (30.2 [interquartile range, 4.4] fibers/mm vs. 11.0 [4.1] fibers/mm, respectively; p = 0.03). Two of these 5 SS patients

  11. Nanedi Vallis: Sustained Water Flow? - High Resolution Image

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This picture of a canyon on the Martian surface was obtained a few minutes after 10 PM PST, January 8, 1998 by the Mars Orbiter Camera (MOC), during the 87th orbit around Mars of the Mars Global Surveyor spacecraft. It shows the canyon of Nanedi Vallis, one of the Martian valley systems cutting through cratered plains in the Xanthe Terra region of Mars. The picture covers an area 9.8 km by 18.5 km (6.1 mi by 11.5 mi), and features as small as 12 m (39 ft) can be seen. The canyon is about 2.5 km (1.6 mi) wide. Rocky outcrops are found along the upper canyon walls; weathered debris found on the lower canyon slopes and along the canyon floor. The origin of this canyon is enigmatic: some features, such as terraces within the canyon (as seen near the top of the frame) and the small 200 m (660 ft) wide channel (also seen near the top of the frame) suggest continual fluid flow and downcutting. Other features, such as the lack of a contributing pattern of smaller channels on the surface surrounding the canyon, box-headed tributaries, and the size and tightness of the apparent meanders (as seen, for example, in the Viking image 89A32), suggest formation by collapse. It is likely that both continual flow and collapse have been responsible for the canyon as it now appears. Further observations, especially in areas west of the present image, will be used to help separate the relative effects of these and other potential formation and modification processes.

    Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  12. Control of High-Speed Spray Flows Using a Steady, Parallel Control Flow Under the Influence of the Coanda Effect

    NASA Astrophysics Data System (ADS)

    Allen, Dustin; Smith, Barton

    2007-11-01

    An experimental demonstration of a jet vectoring technique used in our novel spray device called a Coanda-assisted Spray Manipulation (CSM) nozzle is presented. The CSM makes use of a Coanda-like effect on axisymmetric geometries through the interaction of a high volume-flow primary jet flowing through the center of a collar and a secondary high-momentum jet parallel to the first and adjacent to a convex collar. The control jet attaches to the convex wall and vectors due to the Coanda effect, entraining and vectoring the primary jet, resulting in controllable r-theta directional spraying. Various annular secondary exit holes and curved wall radii were tested over a range of momentum flux ratios to study the effects of these variables on the vectored jet angle. Particle Image Velocimetry (PIV) was used to determine the vectoring angle and the profile of the primary jet in each experiment. The experiments show that the secondary exit hole size and curve wall radius, along with the momentum ratios of the two jets predominantly affect the vectoring angle of the primary jet. Also, the jet profile is largely unchanged with vectoring for high velocity flows, which is important for the thermal spray applications for which CSM will be used.

  13. Hemorheological abnormalities in human arterial hypertension

    NASA Astrophysics Data System (ADS)

    Lo Presti, Rosalia; Hopps, Eugenia; Caimi, Gregorio

    2014-05-01

    Blood rheology is impaired in hypertensive patients. The alteration involves blood and plasma viscosity, and the erythrocyte behaviour is often abnormal. The hemorheological pattern appears to be related to some pathophysiological mechanisms of hypertension and to organ damage, in particular left ventricular hypertrophy and myocardial ischemia. Abnormalities have been observed in erythrocyte membrane fluidity, explored by fluorescence spectroscopy and electron spin resonance. This may be relevant for red cell flow in microvessels and oxygen delivery to tissues. Although blood viscosity is not a direct target of antihypertensive therapy, the rheological properties of blood play a role in the pathophysiology of arterial hypertension and its vascular complications.

  14. Investigation of the jet-wake flow of a highly loaded centrifugal compressor impeller

    NASA Technical Reports Server (NTRS)

    Eckardt, D.

    1978-01-01

    Investigations, aimed at developing a better understanding of the complex flow field in high performance centrifugal compressors were performed. Newly developed measuring techniques for unsteady static and total pressures as well as flow directions, and a digital data analysis system for fluctuating signals were thoroughly tested. The loss-affected mixing process of the distorted impeller discharge flow was investigated in detail, in the absolute and relative system, at impeller tip speeds up to 380 m/s. A theoretical analysis proved good coincidence of the test results with the DEAN-SENOO theory, which was extended to compressible flows.

  15. Nonperiodicity of the flow within the gap of a thermoacoustic couple at high amplitudes.

    PubMed

    Berson, Arganthaël; Blanc-Benon, Philippe

    2007-10-01

    The flow inside a thermoacoustic couple is investigated experimentally using particle image velocimetry. Measurements show the oscillation of the shear layers flowing out of a single stack, thus forming an asymmetric vortex street at high driving amplitudes. Development of vortices is also observed within the gap of a thermoacoustic couple. It causes the flow not to repeat from one acoustic period to another. The nonperiodicity of the flow will lead to unsteady heat transfer between the stack and heat exchangers and to the oscillation of the cooling load. PMID:17902740

  16. High Average Power Laser Gain Medium With Low Optical Distortion Using A Transverse Flowing Liquid Host

    DOEpatents

    Comaskey, Brian J.; Ault, Earl R.; Kuklo, Thomas C.

    2005-07-05

    A high average power, low optical distortion laser gain media is based on a flowing liquid media. A diode laser pumping device with tailored irradiance excites the laser active atom, ion or molecule within the liquid media. A laser active component of the liquid media exhibits energy storage times longer than or comparable to the thermal optical response time of the liquid. A circulation system that provides a closed loop for mixing and circulating the lasing liquid into and out of the optical cavity includes a pump, a diffuser, and a heat exchanger. A liquid flow gain cell includes flow straighteners and flow channel compression.

  17. Red-backed vole brain promotes highly efficient in vitro amplification of abnormal prion protein from macaque and human brains infected with variant Creutzfeldt-Jakob disease agent.

    USGS Publications Warehouse

    Nemecek, Julie; Nag, Nabanita; Carlson, Christina M.; Schneider, Jay R.; Heisey, Dennis M.; Johnson, Christopher J.; Asher, David M.; Gregori, Luisa

    2013-01-01

    Rapid antemortem tests to detect individuals with transmissible spongiform encephalopathies (TSE) would contribute to public health. We investigated a technique known as protein misfolding cyclic amplification (PMCA) to amplify abnormal prion protein (PrPTSE) from highly diluted variant Creutzfeldt-Jakob disease (vCJD)-infected human and macaque brain homogenates, seeking to improve the rapid detection of PrPTSE in tissues and blood. Macaque vCJD PrPTSE did not amplify using normal macaque brain homogenate as substrate (intraspecies PMCA). Next, we tested interspecies PMCA with normal brain homogenate of the southern red-backed vole (RBV), a close relative of the bank vole, seeded with macaque vCJD PrPTSE. The RBV has a natural polymorphism at residue 170 of the PrP-encoding gene (N/N, S/S, and S/N). We investigated the effect of this polymorphism on amplification of human and macaque vCJD PrPTSE. Meadow vole brain (170N/N PrP genotype) was also included in the panel of substrates tested. Both humans and macaques have the same 170S/S PrP genotype. Macaque PrPTSE was best amplified with RBV 170S/S brain, although 170N/N and 170S/N were also competent substrates, while meadow vole brain was a poor substrate. In contrast, human PrPTSE demonstrated a striking narrow selectivity for PMCA substrate and was successfully amplified only with RBV 170S/S brain. These observations suggest that macaque PrPTSE was more permissive than human PrPTSE in selecting the competent RBV substrate. RBV 170S/S brain was used to assess the sensitivity of PMCA with PrPTSE from brains of humans and macaques with vCJD. PrPTSE signals were reproducibly detected by Western blot in dilutions through 10-12 of vCJD-infected 10% brain homogenates. This is the first report showing PrPTSE from vCJD-infected human and macaque brains efficiently amplified with RBV brain as the substrate. Based on our estimates, PMCA showed a sensitivity that might be sufficient to detect PrPTSE in v

  18. Red-backed vole brain promotes highly efficient in vitro amplification of abnormal prion protein from macaque and human brains infected with variant Creutzfeldt-Jakob disease agent.

    PubMed

    Nemecek, Julie; Nag, Nabanita; Carlson, Christina M; Schneider, Jay R; Heisey, Dennis M; Johnson, Christopher J; Asher, David M; Gregori, Luisa

    2013-01-01

    Rapid antemortem tests to detect individuals with transmissible spongiform encephalopathies (TSE) would contribute to public health. We investigated a technique known as protein misfolding cyclic amplification (PMCA) to amplify abnormal prion protein (PrP(TSE)) from highly diluted variant Creutzfeldt-Jakob disease (vCJD)-infected human and macaque brain homogenates, seeking to improve the rapid detection of PrP(TSE) in tissues and blood. Macaque vCJD PrP(TSE) did not amplify using normal macaque brain homogenate as substrate (intraspecies PMCA). Next, we tested interspecies PMCA with normal brain homogenate of the southern red-backed vole (RBV), a close relative of the bank vole, seeded with macaque vCJD PrP(TSE). The RBV has a natural polymorphism at residue 170 of the PrP-encoding gene (N/N, S/S, and S/N). We investigated the effect of this polymorphism on amplification of human and macaque vCJD PrP(TSE). Meadow vole brain (170N/N PrP genotype) was also included in the panel of substrates tested. Both humans and macaques have the same 170S/S PrP genotype. Macaque PrP(TSE) was best amplified with RBV 170S/S brain, although 170N/N and 170S/N were also competent substrates, while meadow vole brain was a poor substrate. In contrast, human PrP(TSE) demonstrated a striking narrow selectivity for PMCA substrate and was successfully amplified only with RBV 170S/S brain. These observations suggest that macaque PrP(TSE) was more permissive than human PrP(TSE) in selecting the competent RBV substrate. RBV 170S/S brain was used to assess the sensitivity of PMCA with PrP(TSE) from brains of humans and macaques with vCJD. PrP(TSE) signals were reproducibly detected by Western blot in dilutions through 10⁻¹² of vCJD-infected 10% brain homogenates. This is the first report showing PrP(TSE) from vCJD-infected human and macaque brains efficiently amplified with RBV brain as the substrate. Based on our estimates, PMCA showed a sensitivity that might be sufficient to detect Pr

  19. High-order ALE schemes for incompressible capillary flows

    NASA Astrophysics Data System (ADS)

    Montefuscolo, Felipe; Sousa, Fabricio S.; Buscaglia, Gustavo C.

    2014-12-01

    The spatial discretization of problems with moving boundaries is considered, incorporating the temporal evolution of not just the mechanical variables, but also of the nodal positions of the moving mesh. The outcome is a system of Differential-Algebraic Equations (DAE) of index 2 or, in the case of inertialess flow, just 1. From the DAE formulation it its possible to define strategies to build schemes of arbitrary accuracy. We introduce here several schemes of order 2 and 3 that avoid the solution of a nonlinear system involving simultaneously the mechanical variables and the geometrical ones. This class of schemes has been the one adopted by the majority of practitioners of Computational Fluid Dynamics up to now. The proposed schemes indeed achieve the design accuracy, and further show stability restrictions that are not significantly more severe than those of popular first order schemes. The numerical experimentation is performed on capillary problems, discretized by both div-stable (P2/P1, P1+/P1) and equal-order (P1/P1, stabilized) finite elements, and incorporating surface tension and triple (contact) line effects.

  20. High Reynolds number effects on a localized stratified turbulent flow

    NASA Astrophysics Data System (ADS)

    Zhou, Qi; Diamessis, Peter

    2015-11-01

    We report large-eddy simulations (LES) of the turbulent flow behind a sphere of diameter D translating at speed U in a linearly stratified Boussinesq fluid with buoyancy frequency N. These simulations are performed using a spectral-multidomain-penalty incompressible Navier-Stokes solver, at Reynolds numbers Re ≡ UD / ν ∈ { 5 ×103 , 105 , 4 ×105 } and Froude numbers Fr ≡ 2 U / (ND) ∈ { 4 , 16 , 64 } . An increasingly richer turbulent fine-structure is observed within the larger-scale quasi-horizontal vortices at later times. Turbulent transport of momentum is examined during the non-equilibrium (NEQ) regime of the turbulent life cycle, with an emphasis on the vertical transport that occurs after the establishment of local buoyancy control. The turbulent viscosities in both horizontal and vertical directions are estimated through the LES data; possible parameterization of the vertical turbulent viscosity with the buoyancy Reynolds number Reb = ɛ / (νN2) (or its easy-to-obtain surrogates) is discussed. The dynamical role of the buoyancy Reynolds number in choosing the vertical turbulence length scales is also investigated. ONR grant N00014-13-1-0665 (managed by Dr. R. Joslin); HPCMP Frontier Project FP-CFD-FY14-007 (P.I.: Dr. S. de Bruyn Kops).

  1. Summary of in-flight flow visualization obtained from the NASA high alpha research vehicle

    NASA Technical Reports Server (NTRS)

    Fisher, David F.; Delfrate, John H.; Zuniga, Fanny A.

    1991-01-01

    A summary of the surface and off-surface flow visualization results obtained in flight on the F-18 high alpha research vehicle (HARV) is presented, highlighting the extensive 3-D vortical flow on the aircraft at angles of attack up to 50 degs. The emitted fluid technique, as well as tufts and flow cones, were used to document the surface flow. A smoke generator system injected smoke into the vortex cores generated by the forebody and leading edge extensions (LEXs). Documentation was provided by onboard still and video, by air-to-air, and by postflight photography. The surface flow visualization techniques revealed laminar separation bubbles near the forebody apex, lines of separation on the forebody and LEX, and regions of attached and separated flow on the wings and fins. The off-surface flow visualization techniques showed the path of the vortex cores on the forebody and LEX as well as the LEX vortex core breakdown location. An interaction between the forebody and LEX vortices was noted. The flow over the surfaces of the vertical tail was categorized into regions of attached, unsteady, or separated flow using flow tufts.

  2. Measurements of mean flow and turbulence characteristics in high-Reynolds number counter-rotating Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    van Hout, R.; Katz, J.

    2011-10-01

    Particle image velocimetry was used for measuring the velocity and Reynolds stress distributions in the latitudinal plane of counter-rotating Taylor-Couette flow at high Reynolds numbers (Re). The ratio of outer to inner cylinder angular velocity, μ, varied between -10.79 and -0.68, and Rei based on the inner cylinder velocity ranged between 2635 and 40 446, substantially extending previously available data. The results were used for examining scaling trends, especially the effects of Re and μ on the mean flow and turbulence statistics. We showed that using a kind of "inner wall" scaling, μ was the primary parameter controlling the normalized profiles of mean velocity, Reynolds stresses, TKE production and dissipation rates. Re effects on the scaled profiles were much smaller. Increasing μ flattened the mean azimuthal velocity profiles in the center of the annulus, increased the radial velocity gradients near the walls, and moved the radial point at which the velocity changed sign towards the outer cylinder. The flow also became more turbulent and a log layer with increasing extent developed near the inner wall. All the Reynolds stress components, along with the TKE production and dissipation rates peaked near the inner wall. Raising μ extended the high turbulence levels deeper into the annulus. At low μ, the stabilizing effect of the outer cylinder kept the flow in the outer regions laminar. Only when the magnitude of the inner cylinder angular velocity equaled or exceeded that of the outer one, the Reynolds stresses remained significant across the entire measurement range, and started increasing also near the outer cylinder. The azimuthal energy spectra confirmed these trends and showed that the changes to turbulence levels occurred at a broad range of scales. Furthermore, for low μ, the instantaneous vorticity fields were dominated by nearly parallel, elongated, counter-rotating vorticity contours, reminiscent of inclined counter-rotating vortex pairs. At

  3. Development of a FBG vortex flow sensor for high-temperature applications

    NASA Astrophysics Data System (ADS)

    Cheng, L. K.; Schiferli, W.; Nieuwland, R. A.; Franzen, A.; den Boer, J. J.; Jansen, T. H.

    2011-05-01

    A robust fibre optic flow sensor has been developed to measure liquid or gas flows at ambient temperatures up to 300 ºC and pressures up to 100 bar. While such environmental conditions are typical in pressurized steam systems in the oil and gas industry (downhole and surface), wider applications are envisaged. The flow sensor uses a specially-designed bluff body to generate vortex-induced pressure fluctuations as a function of flow. The pressure fluctuations result in mechanical strain fluctuations in the sensor plate which is attached to the bluff-body. This is detected by means of a Fibre Bragg Grating (FBG). The frequency of the pressure fluctuations is proportional to the flow velocity and is measured by analyzing the spectrum of the FBG sensor signal. Flow velocity measurements ranging from ~1 m/s to ~25 m/s have been demonstrated. Special mechanical design, gluing and packaging processes have been developed to enable applications at high temperatures and high pressures (HPHT). Although the working principle is the same as for conventional vortex flow meters, this flow sensor does not require electronics, which is a great advantage at high temperatures.

  4. Experimental study of forced convection heat transfer during upward and downward flow of helium at high pressure and high temperature

    SciTech Connect

    Francisco Valentin; Narbeh Artoun; Masahiro Kawaji; Donald M. McEligot

    2015-08-01

    Fundamental high pressure/high temperature forced convection experiments have been conducted in support of the development of a Very High Temperature Reactor (VHTR) with a prismatic core. The experiments utilize a high temperature/high pressure gas flow test facility constructed for forced convection and natural circulation experiments. The test section has a single 16.8 mm ID flow channel in a 2.7 m long, 108 mm OD graphite column with four 2.3kW electric heater rods placed symmetrically around the flow channel. This experimental study presents the role of buoyancy forces in enhancing or reducing convection heat transfer for helium at high pressures up to 70 bar and high temperatures up to 873 degrees K. Wall temperatures have been compared among 10 cases covering the inlet Re numbers ranging from 500 to 3,000. Downward flows display higher and lower wall temperatures in the upstream and downstream regions, respectively, than the upward flow cases due to the influence of buoyancy forces. In the entrance region, convection heat transfer is reduced due to buoyancy leading to higher wall temperatures, while in the downstream region, buoyancyinduced mixing causes higher convection heat transfer and lower wall temperatures. However, their influences are reduced as the Reynolds number increases. This experimental study is of specific interest to VHTR design and validation of safety analysis codes.

  5. Method For Enhanced Gas Monitoring In High Density Flow Streams

    DOEpatents

    Von Drasek, William A.; Mulderink, Kenneth A.; Marin, Ovidiu

    2005-09-13

    A method for conducting laser absorption measurements in high temperature process streams having high levels of particulate matter is disclosed. An impinger is positioned substantially parallel to a laser beam propagation path and at upstream position relative to the laser beam. Beam shielding pipes shield the beam from the surrounding environment. Measurement is conducted only in the gap between the two shielding pipes where the beam propagates through the process gas. The impinger facilitates reduced particle presence in the measurement beam, resulting in improved SNR (signal-to-noise) and improved sensitivity and dynamic range of the measurement.

  6. Cyclic variations of high-frequency ultrasonic backscattering from blood under pulsatile flow.

    PubMed

    Huang, Chih-Chung

    2009-08-01

    It was shown previously that ultrasonic scattering from whole blood varies during the flow cycle under pulsatile flow both in vitro and in vivo. It has been postulated that the cyclic variations of the backscattering signal are associated with red blood cell (RBC) aggregation in flowing whole blood. To obtain a better understanding of the relationship between blood backscattering and RBC aggregation behavior for pulsatile flowing blood, the present study used high-frequency ultrasound to characterize blood properties. The backscattering signals from both whole blood and an RBC suspension at different peak flow velocities (from 10 to 30 cm/s) and hematocrits (20% and 40%) under pulsatile flow (stroke rate of 20 beats/min) were measured with 3 single-element transducers at frequencies of 10, 35, and 50 MHz in a mock flow loop. To avoid the frequency response problem of a Doppler flowmeter, the integrated backscatter (IB) and flow velocity as functions of time were calculated directly using RF signals from flowing blood. The experimental results showed that cyclic variations of the IB curve were clearly observed at a low flow velocity and a hematocrit of 40% when using 50 MHz ultrasound, and that these variations became weaker as the peak flow velocity increased. However, these cyclic variations were detected only at 10 cm/s when using 10 MHz ultrasound. These results demonstrate that a high flow velocity can stop the formation of rouleaux and that a high hematocrit can promote RBC aggregation to produce cyclic variations of the backscattering signal under pulsatile flow. In addition, slight cyclic variations of the IB curve for an RBC suspension were observed at 35 and 50 MHz. Furthermore, the peak of the IB curve from whole blood led the peak of the velocity waveform when using high-frequency ultrasound, which could be explained by the assumption that a rapid flow can promote RBC aggregation under pulsatile flow. Together, the experimental results showed that the

  7. Preliminary design study of a quiet, high flow fan (QHF) stage. [turbofans - quiet engine program

    NASA Technical Reports Server (NTRS)

    Walker, C. L.; Kisner, L. S.; Delaney, R. A.; Beguhn, A. A.; Frye, D. E.

    1974-01-01

    Concepts selected to reduce fan generated noise in a turbofan are presented. Near-sonic flow at the fan inlet to reduce upstream propagated noise and the use of long-chord vanes to reduce downstream noise is discussed. The near-sonic condition at the rotor inlet plane was achieved by designing for high specific mass flow and by maintaining the high flow at reduced power by variable stators and variable fan exhaust nozzle. The long-chord vanes reduce response to unsteady flow. The acoustic design showed that long-chord stators would significantly reduce turbofan source noise and that other stator design parameters have no appreciable effect on noise for the spacing and chord length of the turbofan design. Four rig flow paths studied in the aerodynamic preliminary design are discussed. Noise prediction results indicate that a turbofan powered aircraft would be under federal air regulations levels without any acoustic treatment.

  8. The Lag Model Applied to High Speed Flows

    NASA Technical Reports Server (NTRS)

    Olsen, Michael E.; Coakley, Thomas J.; Lillard, Randolph P.

    2005-01-01

    The Lag model has shown great promise in prediction of low speed and transonic separations. The predictions of the model, along with other models (Spalart-Allmaras and Menter SST) are assessed for various high speed flowfields. In addition to skin friction and separation predictions, the prediction of heat transfer are compared among these models, and some fundamental building block flowfields, are investigated.

  9. Energy flow in high speed perforation and cutting

    SciTech Connect

    van Thiel, M.

    1980-10-07

    It is demonstrated that effects of long rod penetrators on targets can be modeled by introducing a high pressure (energy) column on the penetration path in place of the projectile. This energy can be obtained from the kinetic energy of the penetrator; the equations of state of the materials used and a Bernoulli penetration condition. The model is supported by detailed hydro calculations.

  10. Spontaneous closure of posttraumatic high-flow carotid-cavernous fistula following cerebral angiography

    PubMed Central

    Meena, Ugan Singh; Gupta, Pankaj; Shrivastava, Trilochan; Purohit, Devendra

    2016-01-01

    Traumatic carotid-cavernous fistula (TCCF) is a direct communication between cavernous portion of the internal carotid artery (ICA) and cavernous sinus due to tear in ICA. Most of the cases are treated by endovascular embolization. Spontaneous resolution of high-flow TCCFs is extremely rare. We report a case of posttraumatic, direct, high-flow carotid cavernous fistula (Barrow type A) that resolved spontaneously after cerebral angiography. PMID:27057229

  11. On the peculiarities of LDA method in two-phase flows with high concentrations of particles

    NASA Astrophysics Data System (ADS)

    Poplavski, S. V.; Boiko, V. M.; Nesterov, A. U.

    2016-10-01

    Popular applications of laser Doppler anemometry (LDA) in gas dynamics are reviewed. It is shown that the most popular method cannot be used in supersonic flows and two-phase flows with high concentrations of particles. A new approach to implementation of the known LDA method based on direct spectral analysis, which offers better prospects for such problems, is presented. It is demonstrated that the method is suitable for gas-liquid jets. Owing to the progress in laser engineering, digital recording of spectra, and computer processing of data, the method is implemented at a higher technical level and provides new prospects of diagnostics of high-velocity dense two-phase flows.

  12. High-order discontinuous Galerkin methods for coupled thermoconvective flows under gravity modulation

    NASA Astrophysics Data System (ADS)

    Papanicolaou, N. C.; Aristotelous, A. C.

    2015-10-01

    In this work, we develop a High-Order Symmetric Interior Penalty (SIP) Discontinuous Galerkin (DG) Finite Element Method (FEM) to investigate convective flows in a rectangular cavity subject to both vertical and horizontal temperature gradients. The whole cavity is subject to gravity modulation (g-jitter), simulating a microgravity environment. The sensitivity of the bifurcation problem makes the use of a high-order accurate and efficient technique essential. Our method is validated by solving the plane-parallel flow problem and the results were found to be in good agreement with published results. The numerical method was designed to be easily extendable to even more complex flows.

  13. CFD Simulation of Contaminant Decay for High Reynolds Flow in a Controlled Environment

    PubMed Central

    Lambert, Andrew R.; Lin, Ching-Long; Mardorf, Eunice; O'shaughnessy, Patrick

    2010-01-01

    This study examines the usage of computational fluid dynamics (CFDs) for estimating the time-elapsed decay of contaminants within a chamber experiencing high Reynolds flow. CFD results were compared with measurements taken at a controlled facility. In addition, parameters of the CFD simulation were examined; namely the effects of turbulence and inertial transport at high Reynolds number ventilating flows, as well as inlet duct configuration and its effect on the inlet velocity profile. The agreement between the computational and experimental clearance times was quite good, with percent errors as low as −5.32% at high flow rate and −11.8% at the lower flow rate. This study determined that for high Reynolds flow, diffusive transport effects may be ignored as the majority of mass is transported via the bulk stream, i.e. momentum transport. In addition, resolving the inlet velocity profile was of prime importance for accurate simulation of ventilating flows and prediction of contaminant washout. This was done by including the inlet duct geometry in the computational domain. In addition, it was found that despite different flow rates, the predicted contaminant washout took ∼12–13% longer than predicted assuming instantaneous mixing. Furthermore, percent error between computational and experimental data as low as −5.32% shows that CFD is a useful tool for studying ventilation phenomena. PMID:19671796

  14. The microwave-to-flow paradigm: translating high-temperature batch microwave chemistry to scalable continuous-flow processes.

    PubMed

    Glasnov, Toma N; Kappe, C Oliver

    2011-10-17

    The popularity of dedicated microwave reactors in many academic and industrial laboratories has produced a plethora of synthetic protocols that are based on this enabling technology. In the majority of examples, transformations that require several hours when performed using conventional heating under reflux conditions reach completion in a few minutes or even seconds in sealed-vessel, autoclave-type, microwave reactors. However, one severe drawback of microwave chemistry is the difficulty in scaling this technology to a production-scale level. This Concept article demonstrates that this limitation can be overcome by translating batch microwave chemistry to scalable continuous-flow processes. For this purpose, conventionally heated micro- or mesofluidic flow devices fitted with a back-pressure regulator are employed, in which the high temperatures and pressures attainable in a sealed-vessel microwave chemistry batch experiment can be mimicked.

  15. Chromosome abnormalities in glioma

    SciTech Connect

    Li, Y.S.; Ramsay, D.A.; Fan, Y.S.

    1994-09-01

    Cytogenetic studies were performed in 25 patients with gliomas. An interesting finding was a seemingly identical abnormality, an extra band on the tip of the short arm of chromosome 1, add(1)(p36), in two cases. The abnormality was present in all cells from a patient with a glioblastoma and in 27% of the tumor cells from a patient with a recurrent irradiated anaplastic astrocytoma; in the latter case, 7 unrelated abnormal clones were identified except 4 of those clones shared a common change, -Y. Three similar cases have been described previously. In a patient with pleomorphic astrocytoma, the band 1q42 in both homologues of chromosome 1 was involved in two different rearrangements. A review of the literature revealed that deletion of the long arm of chromosome 1 including 1q42 often occurs in glioma. This may indicate a possible tumor suppressor gene in this region. Cytogenetic follow-up studies were carried out in two patients and emergence of unrelated clones were noted in both. A total of 124 clonal breakpoints were identified in the 25 patients. The breakpoints which occurred three times or more were: 1p36, 1p22, 1q21, 1q25, 3q21, 7q32, 8q22, 9q22, 16q22, and 22q13.

  16. [Congenital foot abnormalities].

    PubMed

    Delpont, M; Lafosse, T; Bachy, M; Mary, P; Alves, A; Vialle, R

    2015-03-01

    The foot may be the site of birth defects. These abnormalities are sometimes suspected prenatally. Final diagnosis depends on clinical examination at birth. These deformations can be simple malpositions: metatarsus adductus, talipes calcaneovalgus and pes supinatus. The prognosis is excellent spontaneously or with a simple orthopedic treatment. Surgery remains outstanding. The use of a pediatric orthopedist will be considered if malposition does not relax after several weeks. Malformations (clubfoot, vertical talus and skew foot) require specialized care early. Clubfoot is characterized by an equine and varus hindfoot, an adducted and supine forefoot, not reducible. Vertical talus combines equine hindfoot and dorsiflexion of the forefoot, which is performed in the midfoot instead of the ankle. Skew foot is suspected when a metatarsus adductus is resistant to conservative treatment. Early treatment is primarily orthopedic at birth. Surgical treatment begins to be considered after walking age. Keep in mind that an abnormality of the foot may be associated with other conditions: malposition with congenital hip, malformations with syndromes, neurological and genetic abnormalities. PMID:25524290

  17. High-resolution mapping of the 1998 lava flows at Axial Seamount

    NASA Astrophysics Data System (ADS)

    Chadwick, B.; Clague, D. A.; Embley, R. W.; Caress, D. W.; Paduan, J. B.; Sasnett, P.

    2011-12-01

    Axial Seamount (an active hotspot volcano on the Juan de Fuca Ridge) last erupted in 1998 and produced two lava flows (a "northern" and a "southern" flow) along the upper south rift zone separated by a distance of 4 km. Geologic mapping of the 1998 lava flows has been carried out with a combination of visual observations from multiple submersible dives since 1998, and with high-resolution bathymetry, most recently collected with the MBARI mapping AUV (the D. Allan B.) since 2007. The new mapping results revise and update the previous preliminary flow outlines, areas, and volumes. The high-resolution bathymetry (1-m grid cell size) allows eruptive fissures fine-scale morphologic features to be resolved with new and remarkable clarity. The morphology of both lava flows can be interpreted as a consequence of a specific sequence of events during their emplacement. The northern sheet flow is long (4.6 km) and narrow (500 m), and erupted in the SE part of Axial caldera, where it temporarily ponded and inflated on relatively flat terrain before draining out southward toward steeper slopes. The inflation and drain-out of this sheet flow by ~ 3.5 m over 2.5 hours was previously documented by a monitoring instrument that was caught in the lava flow. Our geologic mapping shows that the morphology of the northern sheet flow varies along its length primarily due to gradients in the underlying slope and processes active during flow emplacement. The original morphology of the sheet flow where it ponded is lobate, with pillows near the margins, whereas the central axis of drain-out and collapse is floored with lineated, ropy, and jumbled lava morphologies. The southern lava flow, in contrast, is mostly pillow lava where it cascaded down the steep slope on the east flank of the south rift zone, but also has a major area of collapse where lava ponded temporarily near the rift axis. These results show that submarine lava flows have more subsurface hydraulic connectivity than has

  18. In-flight flow visualization characteristics of the NASA F-18 high alpha research vehicle at high angles of attack

    NASA Technical Reports Server (NTRS)

    Fisher, David F.; Delfrate, John H.; Richwine, David M.

    1991-01-01

    Surface and off-surface flow visualization techniques were used to visualize the 3-D separated flows on the NASA F-18 high alpha research vehicle at high angles of attack. Results near the alpha = 25 to 26 deg and alpha = 45 to 49 deg are presented. Both the forebody and leading edge extension (LEX) vortex cores and breakdown locations were visualized using smoke. Forebody and LEX vortex separation lines on the surface were defined using an emitted fluid technique. A laminar separation bubble was also detected on the nose cone using the emitted fluid technique and was similar to that observed in the wind tunnel test, but not as extensive. Regions of attached, separated, and vortical flow were noted on the wing and the leading edge flap using tufts and flow cones, and compared well with limited wind tunnel results.

  19. Technical Evaluation Report, Part A - Vortex Flow and High Angle of Attack

    NASA Technical Reports Server (NTRS)

    Luckring, James M.

    2003-01-01

    A symposium entitled Vortex Flow and High Angle of Attack was held in Loen, Norway, from May 7 through May 11, 2001. The Applied Vehicle Technology (AVT) panel, under the auspices of the Research and Technology Organization (RTO), sponsored this symposium. Forty-eight papers, organized into nine sessions, addressed computational and experimental studies of vortex flows pertinent to both aircraft and maritime applications. The studies also ranged from fundamental fluids investigations to flight test results, and significant results were contributed from a broad range of countries. The principal emphasis of this symposium was on "the understanding and prediction of separation-induced vortex flows and their effects on military vehicle performance, stability, control, and structural design loads." It was further observed by the program committee that "separation- induced vortex flows are an important part of the design and off-design performance of conventional fighter aircraft and new conventional or unconventional manned or unmanned advanced vehicle designs (UAVs, manned aircraft, missiles, space planes, ground-based vehicles, and ships)." The nine sessions addressed the following topics: vortical flows on wings and bodies, experimental techniques for vortical flows, numerical simulations of vortical flows, vortex stability and breakdown, vortex flows in maritime applications, vortex interactions and control, vortex dynamics, flight testing, and vehicle design. The purpose of this paper is to provide brief reviews of these papers along with some synthesizing perspectives toward future vortex flow research opportunities. The paper includes the symposium program. (15 refs.)

  20. High-Resolution Simulations of Gas-Solids Jet Penetration Into a High Density Riser Flow

    SciTech Connect

    Li, Tingwen

    2011-05-01

    High-resolution simulations of a gas-solids jet in a 0.3 m diameter and 15.9 m tall circulating fluidized bed (CFB) riser were conducted with the open source software-MFIX. In the numerical simulations, both gas and solids injected through a 1.6 cm diameter radial-directed tube 4.3 m above the bottom distributor were tracked as tracers, which enable the analysis of the characteristics of a two-phase jet. Two jetting gas velocities of 16.6 and 37.2 m/s were studied with the other operating conditions fixed. Reasonable flow hydrodynamics with respect to overall pressure drop, voidage, and solids velocity distributions were predicted. Due to the different dynamic responses of gas and particles to the crossflow, a significant separation of gas and solids within the jet region was predicted for both cases. In addition, the jet characteristics based on tracer concentration and tracer mass fraction profiles at different downstream levels are discussed. Overall, the numerical predictions compare favorably to the experimental measurements made at NETL.

  1. High Latitude Meridional Flow on the Sun May Explain North-South Polar Field Asymmetry

    NASA Technical Reports Server (NTRS)

    Kosak, Katie; Upton, Lisa; Hathaway, David

    2012-01-01

    We measured the flows of magnetic elements on the Sun at very high latitudes by analyzing magnetic images from the Helioseismic and Magnetic Imager (HMI) on the NASA Solar Dynamics Observatory (SDO) Mission. Magnetic maps constructed using a fixed, and north-south symmetric, meridional flow profile give weaker than observed polar fields in the North and stronger than observed polar fields in the South during the decline of Cycle 23 and rise of Cycle 24. Our measurements of the meridional flow at high latitudes indicate systematic north-south differences. In the fall of 2010 (when the North Pole was most visible), there was a strong flow in the North while in the spring of 2011 (when the South Pole was most visible) the flow there was weaker. With these results, we have a possible solution to this polar field asymmetry. The weaker flow in the South should keep the polar fields from becoming too strong while the stronger flow in the North should strengthen the field there. In order to gain a better understanding of the Solar Cycle and magnetic flux transport on the Sun, we need further observations and analyses of the Sun s polar regions in general and the polar meridional flow in particular.

  2. High Latitude Meridional Flow on the Sun May Explain North-South Polar Field Asymmetry

    NASA Technical Reports Server (NTRS)

    Kosak, Katie; Upton, Lisa; Hathaway, David

    2012-01-01

    We measured the flows of magnetic elements on the Sun at very high latitudes by analyzing magnetic images from the Helioseismic and Magnetic Imager (HMI) on the NASA Solar Dynamics Observatory (SDO) Mission. Magnetic maps constructed using a fixed, and north-south symmetric, meridional flow profile give weaker than observed polar fields in the North and stronger than observed polar fields in the South during the decline of Cycle 23 and rise of Cycle 24. Our measurements of the meridional flow at high latitudes indicate systematic north-south differences. There was a strong flow in the North while the flow in the South was weaker. With these results, we have a possible solution to the polar field asymmetry. The weaker flow in the South should keep the polar fields from becoming too strong while the stronger flow in the North should strengthen the field there. In order to gain a better understanding of the Solar Cycle and magnetic flux transport on the Sun, we need further observations and analyses of the Sun's polar regions in general and the polar meridonal flow in particular.

  3. High Latitude Meridional Flow on the Sun May Explain North-South Polar Field Asymmetry

    NASA Technical Reports Server (NTRS)

    Kosak, Katie; Upton, Lisa; Hathaway, David

    2012-01-01

    We measured the flows of magnetic elements on the Sun at very high latitudes by analyzing magnetic images from the Helioseismic and Magnetic Imager (HMI) on the NASA Solar Dynamics Observatory (SDO) Mission. Magnetic maps constructed using a fixed, and north ]south symmetric, meridional flow profile give weaker than observed polar fields in the North and stronger than observed polar fields in the South during the decline of Cycle 23 and rise of Cycle 24. Our measurements of the meridional flow at high latitudes indicate systematic north ]south differences. There was a strong flow in the North while the flow in the South was weaker. With these results, we have a possible solution to the polar field asymmetry. The weaker flow in the South should keep the polar fields from becoming too strong while the stronger flow in the North should strengthen the field there. In order to gain a better understanding of the Solar Cycle and magnetic flux transport on the Sun, we need further observations and analyses of the Sun fs polar regions in general and the polar meridional flow in particular

  4. Numerical aspects in modeling high Deborah number flow and elastic instability

    NASA Astrophysics Data System (ADS)

    Kwon, Youngdon

    2014-05-01

    Investigating highly nonlinear viscoelastic flow in 2D domain, we explore problem as well as property possibly inherent in the streamline upwinding technique (SUPG) and then present various results of elastic instability. The mathematically stable Leonov model written in tensor-logarithmic formulation is employed in the framework of finite element method for spatial discretization of several representative problem domains. For enhancement of computation speed, decoupled integration scheme is applied for shear thinning and Boger-type fluids. From the analysis of 4:1 contraction flow at low and moderate values of the Deborah number (De) the solution with SUPG method does not show noticeable difference from the one by the computation without upwinding. On the other hand, in the flow regime of high De, especially in the state of elastic instability the SUPG significantly distorts the flow field and the result differs considerably from the solution acquired straightforwardly. When the strength of elastic flow and thus the nonlinearity further increase, the computational scheme with upwinding fails to converge and evolutionary solution does not become available any more. All this result suggests that extreme care has to be taken on occasions where upwinding is applied, and one has to first of all prove validity of this algorithm in the case of high nonlinearity. On the contrary, the straightforward computation with no upwinding can efficiently model representative phenomena of elastic instability in such benchmark problems as 4:1 contraction flow, flow over a circular cylinder and flow over asymmetric array of cylinders. Asymmetry of the flow field occurring in the symmetric domain, enhanced spatial and temporal fluctuation of dynamic variables and flow effects caused by extension hardening are properly described in this study.

  5. MICROSCALE FLOW INJECTION AND MICROBORE HIGH-PERFORMANCE LIQUID CHROMATORGRAPHY COUPLED WITH INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY VIA A HIGH-EFFICIENCY NEBULIZER

    EPA Science Inventory

    A high-effeciency nebulizer has been used for coupling microscale flow injection and microbore high-performance liquid chromatography with inductively coupled plasma mass spectrometry (ICPMS). The microscale flow injection system was configured to minimize band broadening between...

  6. Liquid fuel spray processes in high-pressure gas flow

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.

    1986-01-01

    Atomization of single liquid jets injected downstream in high pressure and high velocity airflow was investigated to determine the effect of airstream pressure on mean drop size as measured with a scanning radiometer. For aerodynamic - wave breakup of liquid jets, the ratio of orifice diameter D sub o to measured mean drop diameter D sub m which is assumed equal to D sub 32 or Sauter mean diameter, was correlated with the product of the Weber and Reynolds numbers WeRe and the dimensionless group G1/square root of c, where G is the gravitational acceleration, 1 the mean free molecular path, and square root of C the root mean square velocity, as follows; D sub o/D sub 32 = 1.2 (WeRe) to the 0.4 (G1/square root of c) to the 0.15 for values of WeRe 1 million and an airstream pressure range of 0.10 to 2.10 MPa.

  7. Liquid fuel spray processes in high-pressure gas flow

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.

    1985-01-01

    Atomization of single liquid jets injected downstream in high pressure and high velocity airflow was investigated to determine the effect of airstream pressure on mean drop size as measured with a scanning radiometer. For aerodynamic - wave breakup of liquid jets, the ratio of orifice diameter D sub o to measured mean drop diameter D sub m which is assumed equal to D sub 32 or Sauter mean diameter, was correlated with the product of the Weber and Reynolds numbers WeRe and the dimensionless group G1/square root of c, where G is the gravitational acceleration, 1 the mean free molecular path, and square root of C the root mean square velocity, as follows; D sub o/D sub 32 = 1.2 (WeRe) to the 0.4 (G1/square root of c) to the 0.15 for values of WeRe 1 million and an airstream pressure range of 0.10 to 2.10 MPa.

  8. High-altitude gas releases - Transition from collisionless flow to diffusive flow in a nonuniform atmosphere

    NASA Technical Reports Server (NTRS)

    Bernhardt, P. A.

    1979-01-01

    The paper is motivated by a need for describing high-altitude gas releases from rockets or the Space Shuttle. In the tenuous upper atmosphere, the injected gases expand from a collisionless to a collision-dominated state. The analysis presented extends the efforts of Baum (1973-1974) to include the effects of a nonuniform background atmosphere and a velocity-dependent collision frequency. The unsteady expansion of gas releases is analyzed using gas kinetic theory. The Boltzmann equation with the Krook collision integral is solved numerically. At late times (after many collisions with the background atmosphere) the solution is identical to the one given by diffusion in a nonuniform atmosphere (Bernhardt, 1979). The theoretical model predicts elongation and heating of the vapor trails due to collisions.

  9. Flow and Noise Control in High Speed and High Reynolds Number Jets Using Plasma Actuators

    NASA Technical Reports Server (NTRS)

    Samimy, M.; Kastner, J.; Kim, J.-H.; Utkin, Y.; Adamovich, I.; Brown, C. A.

    2006-01-01

    The idea of manipulating flow to change its characteristics is over a century old. Manipulating instabilities of a jet to increase its mixing and to reduce its radiated noise started in the 1970s. While the effort has been successful in low-speed and low Reynolds number jets, available actuators capabilities in terms of their amplitude, bandwidth, and phasing have fallen short in control of high-speed and high Reynolds number jets of practical interest. Localized arc filament plasma actuators have recently been developed and extensively used at Gas Dynamics and Turbulence Laboratory (GDTL) for control of highspeed and high Reynolds number jets. While the technique has been quite successful and is very promising, all the work up to this point had been carried out using small high subsonic and low supersonic jets from a 2.54 cm diameter nozzle exit with a Reynolds number of about a million. The preliminary work reported in this paper is a first attempt to evaluate the scalability of the technique. The power supply/plasma generator was designed and built in-house at GDTL to operate 8 actuators simultaneously over a large frequency range (0 to 200 kHz) with independent control over phase and duty cycle of each actuator. This allowed forcing the small jet at GDTL with azimuthal modes m = 0, 1, 2, 3, plus or minus 1, plus or minus 2, and plus or minus 4 over a large range of frequencies. This power supply was taken to and used, with minor modifications, at the NASA Nozzle Acoustic Test Rig (NATR). At NATR, 32 actuators were distributed around the 7.5 in. nozzle (a linear increase with nozzle exit diameter would require 60 actuators). With this arrangement only 8 actuators could operate simultaneously, thus limiting the forcing of the jet at NATR to only three azimuthal modes m = plus or minus 1, 4, and 8. Very preliminary results at NATR indicate that the trends observed in the larger NASA facility in terms of the effects of actuation frequency and azimuthal modes are

  10. Quartz measurement in coal dust with high-flow rate samplers: laboratory study.

    PubMed

    Lee, Taekhee; Lee, Eun Gyung; Kim, Seung Won; Chisholm, William P; Kashon, Michael; Harper, Martin

    2012-05-01

    A laboratory study was performed to measure quartz in coal dust using high-flow rate samplers (CIP10-R, GK2.69 cyclone, and FSP10 cyclone) and low-flow rate samplers [10-mm nylon and Higgins-Dewell type (BGI4L) cyclones] and to determine whether an increased mass collection from high-flow rate samplers would affect the subsequent quartz measurement by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analytical procedures. Two different sizes of coal dusts, mass median aerodynamic diameter 4.48 μm (Coal Dust A) and 2.33 μm (Coal Dust B), were aerosolized in a calm air chamber. The mass of coal dust collected by the samplers was measured gravimetrically, while the mass of quartz collected by the samplers was determined by FTIR (NIOSH Manual of Analytical Method 7603) and XRD (NIOSH Manual of Analytical Method 7500) after one of two different indirect preparations. Comparisons between high-flow rate samplers and low-flow rate samplers were made by calculating mass concentration ratios of coal dusts, net mass ratios of coal dusts, and quartz net mass. Mass concentrations of coal dust from the FSP10 cyclone were significantly higher than those from other samplers and mass concentrations of coal dust from 10-mm nylon cyclone were significantly lower than those from other samplers, while the CIP10-R, GK2.69, and BGI4L samplers did not show significant difference in the comparison of mass concentration of coal dusts. The BGI4L cyclone showed larger mass concentration of ∼9% compared to the 10-mm nylon cyclone. All cyclones provided dust mass concentrations that can be used in complying with the International Standard Organization standard for the determination of respirable dust concentration. The amount of coal dust collected from the high-flow rate samplers was found to be higher with a factor of 2-8 compared to the low-flow rate samplers but not in direct proportion of increased flow rates. The high-flow rate samplers collected more quartz compared to

  11. High-Performance data flows using analytical models and measurements

    SciTech Connect

    Rao, Nageswara S; Towlsey, D.; Vardoyan, G.; Kettimuthu, R.; Foster, I.; Settlemyer, Bradley

    2016-01-01

    The combination of analytical models and measurements provide practical configurations and parameters to achieve high data transport rates: (a) buffer sizes and number of parallel streams for improved memory and file transfer rates, (b) Hamilton and Scalable TCP congestion control modules for memory transfers in place of default CUBIC, and (c) direct IO mode for Lustre file systems for wide-area transfers. Conventional parameter selection using full sweeps is impractical in many cases since it takes months. By exploiting the unimodality of throughput profiles, we developed the d-w method that significantly reduces the number of measurements needed for parameter identification. This heuristic method was effective in practice in reducing the measurements by about 90% for Lustre and XFS file transfers.

  12. A high order accurate difference scheme for complex flow fields

    SciTech Connect

    Dexun Fu; Yanwen Ma

    1997-06-01

    A high order accurate finite difference method for direct numerical simulation of coherent structure in the mixing layers is presented. The reason for oscillation production in numerical solutions is analyzed. It is caused by a nonuniform group velocity of wavepackets. A method of group velocity control for the improvement of the shock resolution is presented. In numerical simulation the fifth-order accurate upwind compact difference relation is used to approximate the derivatives in the convection terms of the compressible N-S equations, a sixth-order accurate symmetric compact difference relation is used to approximate the viscous terms, and a three-stage R-K method is used to advance in time. In order to improve the shock resolution the scheme is reconstructed with the method of diffusion analogy which is used to control the group velocity of wavepackets. 18 refs., 12 figs., 1 tab.

  13. [Identification and quantitation of purine derivatives in urinary calculi as markers of abnormal purine metabolism by using high-performance liquid chromatography (HPLC)].

    PubMed

    Safranow, K

    2000-01-01

    The objective of this study was to develop a practical method for the analysis of purine derivatives in urinary calculi using high-performance liquid chromatography (HPLC). The method presented herein includes extraction of purine derivatives from urinary stones, followed by chromatography on a reversed-phase column with UV detection. A simpler isocratic method was applied to quantitate 6 purines known to be components of urinary stones, namely uric acid, xanthine, hypoxanthine, 2,8-dihydroxyadenine, oxypurinol and allopurinol. Gradient method separated 10 additional peaks representing methyl derivatives of uric acid or xanthine (1-, 3-, 7-, and 9-methyluric acid, 1,3-,1,7-, and 3,7-dimethyluric acid, and 1-, 3-, and 7-methylxanthine) (Fig. 1). Detection limits for individual compounds ranged from 25 to 140 micrograms purine per g stone weight and precision (RSD%) was 0.5-2.4%. Both methods were next used to analyze purine derivatives in urinary calculi from 48 residents of Western Pomerania. Uric acid was the main component of 9 stones. All of the uric acid stones showed admixtures of 9 other purine derivatives: natural metabolites (hypoxanthine, xanthine, 2,8-dihydroxyadenine) and methyl derivatives of uric acid (1-,3-, and 7-methyluric acid, 1,3-dimethyluric acid, 3-, and 7-methylxanthine) originating from the metabolism of exogenous methylxanthines (caffeine, theophylline and theobromine) (Tab. 1,2). Methyl derivatives of uric acid and xanthine, with a maximal content in stones of 1.7%, have hitherto not been considered constituents of urinary calculi. Statistical analysis of the results revealed strong positive correlations between the level of uric acid and of other purine derivatives in stones (Fig. 2). Correlations were also found between levels of some purines and inorganic compounds (Tab. 3). The sensitivity and specificity of HPLC with UV detection satisfy the requirements of a reference method for the analysis of purines in urinary stones. Isocratic

  14. Feeling Abnormal: Simulation of Deviancy in Abnormal and Exceptionality Courses.

    ERIC Educational Resources Information Center

    Fernald, Charles D.

    1980-01-01

    Describes activity in which student in abnormal psychology and psychology of exceptional children classes personally experience being judged abnormal. The experience allows the students to remember relevant research, become sensitized to the feelings of individuals classified as deviant, and use caution in classifying individuals as abnormal.…

  15. Large eddy simulations and direct numerical simulations of high speed turbulent reacting flows

    NASA Technical Reports Server (NTRS)

    Givi, P.; Madnia, C. K.; Steinberger, C. J.; Frankel, S. H.; Vidoni, T. J.

    1991-01-01

    The main objective is to extend the boundaries within which large eddy simulations (LES) and direct numerical simulations (DNS) can be applied in computational analyses of high speed reacting flows. In the efforts related to LES, we were concerned with developing reliable subgrid closures for modeling of the fluctuation correlations of scalar quantities in reacting turbulent flows. In the work on DNS, we focused our attention to further investigation of the effects of exothermicity in compressible turbulent flows. In our previous work, in the first year of this research, we have considered only 'simple' flows. Currently, we are in the process of extending our analyses for the purpose of modeling more practical flows of current interest at LaRC. A summary of our accomplishments during the third six months of the research is presented.

  16. Some Experiences with High Order Discretization Schemes for Compressible Fluid Flow

    NASA Technical Reports Server (NTRS)

    Barth, Timothy J.; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    It is widely recognized that the structure and complexity of compressible fluid flow places high demands on numerical discretization techniques for the fluid flow equations. Fluid flows arising in external aerodynamics often contain both flow field discontinuities and fluid boundary-layers. Both must be accurately resolved to provide useful information to aerodynamic design and analysis engineers. These accuracy requirements motivated the present author to examine a class of finite-volume techniques on arbitrary triangulated domains based on linear or quadratic reconstruction of integral-averaged data followed by upwind flux function evaluation and small time evolution. More recently, we have considered some new upwind techniques which yield compact discretizations while maintaining higher order accuracy. In the mini-symposium talk we will discuss both of these techniques as well as demonstrate the relative merits of each method by computing a number of aerodynamic flows containing shock waves and boundary-layers.

  17. Applications of an adaptive unstructured solution algorithm to the analysis of high speed flows

    NASA Technical Reports Server (NTRS)

    Thareja, R. R.; Prabhu, R. K.; Morgan, K.; Peraire, J.; Peiro, J.

    1990-01-01

    An upwind cell-centered scheme for the solution of steady laminar viscous high-speed flows is implemented on unstructured two-dimensional meshes. The first-order implementation employs Roe's (1981) approximate Riemann solver, and a higher-order extension is produced by using linear reconstruction with limiting. The procedure is applied to the solution of inviscid subsonic flow over an airfoil, inviscid supersonic flow past a cylinder, and viscous hypersonic flow past a double ellipse. A detailed study is then made of a hypersonic laminar viscous flow on a 24-deg compression corner. It is shown that good agreement is achieved with previous predictions using finite-difference and finite-volume schemes. However, these predictions do not agree with experimental observations. With refinement of the structured grid at the leading edge, good agreement with experimental observations for the distributions of wall pressure, heating rate and skin friction is obtained.

  18. Pressure driven flow studies of superfluid helium-4 through single, high aspect ratio nanopipes

    NASA Astrophysics Data System (ADS)

    Botimer, Jeffrey; Taborek, Peter

    We have measured flow rates of helium-4 through high aspect ratio (>10,000) single glass nanopipes and etched nanopores under the influence of a pressure drop. The initial diameter of the glass pipes is 200nm while the initial diameter of the nanopores is approximately 80nm; the diameter of both types of nanopipe were reduced using atomic layer deposition(ALD) of Al2O3. Flow rates were measured for a wide range of temperatures (0.8K to 3.0K), pressures (up to 40 atm), and pipe lengths (0.8 mm to 30 mm). We observed flow velocities in the range of 1-6 m/s which has a power law dependence on pressure. Flow appears to be governed by turbulence at low temperatures. We have found evidence for a critical pressure above which turbulent flow is eliminated. This critical pressure appears to depend on temperature.

  19. Large eddy simulations and direct numerical simulations of high speed turbulent reacting flows

    NASA Technical Reports Server (NTRS)

    Givi, Peyman; Madnia, C. K.; Steinberger, C. J.; Tsai, A.

    1991-01-01

    This research is involved with the implementations of advanced computational schemes based on large eddy simulations (LES) and direct numerical simulations (DNS) to study the phenomenon of mixing and its coupling with chemical reactions in compressible turbulent flows. In the efforts related to LES, a research program was initiated to extend the present capabilities of this method for the treatment of chemically reacting flows, whereas in the DNS efforts, focus was on detailed investigations of the effects of compressibility, heat release, and nonequilibrium kinetics modeling in high speed reacting flows. The efforts to date were primarily focussed on simulations of simple flows, namely, homogeneous compressible flows and temporally developing hign speed mixing layers. A summary of the accomplishments is provided.

  20. Power flow in long MITLs with high-inductance loads

    SciTech Connect

    Poukey, J.W.; Mazarkis, M.G.

    1994-12-31

    The authors are using the 2-D TWOQUICK simulation code to study a system consisting of a voltage adder, a long magnetically-insulated transmission line (MITL), and a large-inductance load which includes a conducting foil (short circuit). The object of this work is to produce a voltage pulse of typically 10 MV and several hundred ns which travels down a MITL of about 10 meters length and 5--10 ohms vacuum impedance, and then couples efficiently to a load of a few hundred nH inductance. They discuss modeling issues such as the use of simple transmission lines for parts of the system, and methods for representing the load. Important physics issues include voltage-pulse erosion in long MITLs, effects of reflected waves from the highly overmatched load impedance, and energy fraction delivered to the load. They calculate electron losses in all parts of the system. Parameter variations of interest include input voltage waveform, adder geometry, MITL length and impedance, and loaded configuration and inductance. Comparisons with circuit models (SCREAMER) will be shown.

  1. Abnormal human sex chromosome constitutions

    SciTech Connect

    1993-12-31

    Chapter 22, discusses abnormal human sex chromosome constitution. Aneuploidy of X chromosomes with a female phenotype, sex chromosome aneuploidy with a male phenotype, and various abnormalities in X chromosome behavior are described. 31 refs., 2 figs.

  2. Exercises to Improve Gait Abnormalities

    MedlinePlus

    ... Home About iChip Articles Directories Videos Resources Contact Exercises to Improve Gait Abnormalities Home » Article Categories » Exercise and Fitness Font Size: A A A A Exercises to Improve Gait Abnormalities Next Page The manner ...

  3. Nasal High-Flow Therapy for Primary Respiratory Support in Preterm Infants.

    PubMed

    Roberts, Calum T; Owen, Louise S; Manley, Brett J; Frøisland, Dag H; Donath, Susan M; Dalziel, Kim M; Pritchard, Margo A; Cartwright, David W; Collins, Clare L; Malhotra, Atul; Davis, Peter G

    2016-09-22

    Background Treatment with nasal high-flow therapy has efficacy similar to that of nasal continuous positive airway pressure (CPAP) when used as postextubation support in neonates. The efficacy of high-flow therapy as the primary means of respiratory support for preterm infants with respiratory distress has not been proved. Methods In this international, multicenter, randomized, noninferiority trial, we assigned 564 preterm infants (gestational age, ≥28 weeks 0 days) with early respiratory distress who had not received surfactant replacement to treatment with either nasal high-flow therapy or nasal CPAP. The primary outcome was treatment failure within 72 hours after randomization. Noninferiority was determined by calculating the absolute difference in the risk of the primary outcome; the chosen margin of noninferiority was 10 percentage points. Infants in whom high-flow therapy failed could receive rescue CPAP; infants in whom CPAP failed were intubated and mechanically ventilated. Results Trial recruitment stopped early at the recommendation of the independent data and safety monitoring committee because of a significant difference in the primary outcome between treatment groups. Treatment failure occurred in 71 of 278 infants (25.5%) in the high-flow group and in 38 of 286 infants (13.3%) in the CPAP group (risk difference, 12.3 percentage points; 95% confidence interval [CI], 5.8 to 18.7; P<0.001). The rate of intubation within 72 hours did not differ significantly between the high-flow and CPAP groups (15.5% and 11.5%, respectively; risk difference, 3.9 percentage points; 95% CI, -1.7 to 9.6; P=0.17), nor did the rate of adverse events. Conclusions When used as primary support for preterm infants with respiratory distress, high-flow therapy resulted in a significantly higher rate of treatment failure than did CPAP. (Funded by the National Health and Medical Research Council and others; Australian New Zealand Clinical Trials Registry number, ACTRN

  4. Nasal High-Flow Therapy for Primary Respiratory Support in Preterm Infants.

    PubMed

    Roberts, Calum T; Owen, Louise S; Manley, Brett J; Frøisland, Dag H; Donath, Susan M; Dalziel, Kim M; Pritchard, Margo A; Cartwright, David W; Collins, Clare L; Malhotra, Atul; Davis, Peter G

    2016-09-22

    Background Treatment with nasal high-flow therapy has efficacy similar to that of nasal continuous positive airway pressure (CPAP) when used as postextubation support in neonates. The efficacy of high-flow therapy as the primary means of respiratory support for preterm infants with respiratory distress has not been proved. Methods In this international, multicenter, randomized, noninferiority trial, we assigned 564 preterm infants (gestational age, ≥28 weeks 0 days) with early respiratory distress who had not received surfactant replacement to treatment with either nasal high-flow therapy or nasal CPAP. The primary outcome was treatment failure within 72 hours after randomization. Noninferiority was determined by calculating the absolute difference in the risk of the primary outcome; the chosen margin of noninferiority was 10 percentage points. Infants in whom high-flow therapy failed could receive rescue CPAP; infants in whom CPAP failed were intubated and mechanically ventilated. Results Trial recruitment stopped early at the recommendation of the independent data and safety monitoring committee because of a significant difference in the primary outcome between treatment groups. Treatment failure occurred in 71 of 278 infants (25.5%) in the high-flow group and in 38 of 286 infants (13.3%) in the CPAP group (risk difference, 12.3 percentage points; 95% confidence interval [CI], 5.8 to 18.7; P<0.001). The rate of intubation within 72 hours did not differ significantly between the high-flow and CPAP groups (15.5% and 11.5%, respectively; risk difference, 3.9 percentage points; 95% CI, -1.7 to 9.6; P=0.17), nor did the rate of adverse events. Conclusions When used as primary support for preterm infants with respiratory distress, high-flow therapy resulted in a significantly higher rate of treatment failure than did CPAP. (Funded by the National Health and Medical Research Council and others; Australian New Zealand Clinical Trials Registry number, ACTRN

  5. Review of numerical simulations for high-speed, turbulent cavity flows

    NASA Astrophysics Data System (ADS)

    Lawson, S. J.; Barakos, G. N.

    2011-04-01

    High speed flows inside cavities are encountered in many aerospace applications including weapon bays of combat aircraft as well as landing gear. The flow field inside these cavities is associated with strong acoustic effects, unsteadiness and turbulence. With increasing emphasis on stealth operation of unmanned combat air vehicles and noise concerns near airports, cavity flows attracted the interest of many researchers in aerodynamics and aeroacoustics. Several attempts were made using wind tunnel experimentation and computational fluid dynamics analyses to understand the complex flow physics associated with cavity flows and alleviate their adverse effects via flow control. The problem proved to be complex, and current research revealed a very complex flow with several flow phenomena taking place. With the aid of experiments, CFD methods were validated and then used for simulations of several cavity configurations. The detached-eddy and large-eddy simulation methods proved invaluable for these studies and their application highlights the need for advanced turbulence simulation techniques in aerospace. The success of these methods and a summary of the current status of the experimental and computational progress over the past twenty years is summarised in this paper.

  6. Simulation of three-dimensional shear flow around a nozzle-afterbody at high speeds

    SciTech Connect

    Baysal, O.; Hoffman, W.B. )

    1992-06-01

    In this paper, turbulent shear flows at supersonic and hypersonic speeds around a nozzle-afterbody are simulated. The three-dimensional, Reynolds-averaged Navier-Stokes equations are solved by a finite-volume and implicit method. The convective and the pressure terms are differenced by an upwind-biased algorithm. The effect of turbulence is incorporated by a modified Baldwin-Lomax eddy viscosity model. The success of the standard Baldwin-Lomax model for this flow type is shown by comparing it to a laminar case. These modifications made to the model are also shown to improve flow prediction when compared to the standard Baldwin-Lomax model. These modifications to the model reflect the effects of high compressibility, multiple walls, vortices near walls, and turbulent memory effects in the shear layer. This numerically simulated complex flowfield includes a supersonic duct flow, a hypersonic flow over an external double corner, a flow through a non-axisymmetric, internal-external nozzle, and a three-dimensional shear layer. The specific application is for the flow around the nozzle-afterbody of a generic hypersonic vehicle powered by a scramjet engine. The computed pressure distributions compared favorably with the experimentally obtained surface and off-surface flow surveys.

  7. High-resolution Impedance Manometry Measurement of Bolus Flow Time in Achalasia and its Correlation with Dysphagia

    PubMed Central

    Lin, Zhiyue; Carlson, Dusty; Dykstra, Kristina; Sternbach, Joel; Hungness, Eric; Kahrilas, Peter J.; Ciolino, Jody D.; Pandolfino, John E.

    2015-01-01

    Background We assessed whether a high-resolution impedance manometry (HRIM) metric, bolus flow time (BFT) across the esophagogastric junction (EGJ), was abnormal in achalasia patients subtyped by the Chicago Classification and compared BFT to other HRM metrics. Methods HRIM studies were performed in 60 achalasia patients (14 type I, 36 type II and 10 type III) and 15 healthy controls. Studies were analyzed with a MATLAB program to calculate BFT using a virtual HRIM sleeve. Integrated relaxation pressure (IRP) and basal end-expiratory EGJ pressure were also calculated. The relationship between BFT and dysphagia symptom scores was assessed using the impaction dysphagia questionnaire (IDQ). Key Results Median BFT was significantly lower in achalasia patients (0.5 s, range 0.0 to 3.5 s) compared to controls (3.5 s, range 2.0 to 5.0 s) (P<0.05). BFT was significantly lower in types I and II than in type III achalasia in both the supine and upright positions (p<0.0001). BFT was the only HRIM metric significantly associated with IDQ score in both the supine (R2 =0.20, p=0.0046) and upright positions (R2 =0.27, p=0.0002). Conclusions & Inferences BFT was significantly reduced in all subtypes of achalasia and complementary to the IRP as a diagnostic discriminant in equivocal achalasia cases. Additionally, BFT had a more robust correlation with dysphagia severity compared to other metrics of EGJ function. PMID:26088614

  8. Investigation on the Core Bypass Flow in a Very High Temperature Reactor

    SciTech Connect

    Hassan, Yassin

    2013-10-22

    Uncertainties associated with the core bypass flow are some of the key issues that directly influence the coolant mass flow distribution and magnitude, and thus the operational core temperature profiles, in the very high-temperature reactor (VHTR). Designers will attempt to configure the core geometry so the core cooling flow rate magnitude and distribution conform to the design values. The objective of this project is to study the bypass flow both experimentally and computationally. Researchers will develop experimental data using state-of-the-art particle image velocimetry in a small test facility. The team will attempt to obtain full field temperature distribution using racks of thermocouples. The experimental data are intended to benchmark computational fluid dynamics (CFD) codes by providing detailed information. These experimental data are urgently needed for validation of the CFD codes. The following are the project tasks: • Construct a small-scale bench-top experiment to resemble the bypass flow between the graphite blocks, varying parameters to address their impact on bypass flow. Wall roughness of the graphite block walls, spacing between the blocks, and temperature of the blocks are some of the parameters to be tested. • Perform CFD to evaluate pre- and post-test calculations and turbulence models, including sensitivity studies to achieve high accuracy. • Develop the state-of-the art large eddy simulation (LES) using appropriate subgrid modeling. • Develop models to be used in systems thermal hydraulics codes to account and estimate the bypass flows. These computer programs include, among others, RELAP3D, MELCOR, GAMMA, and GAS-NET. Actual core bypass flow rate may vary considerably from the design value. Although the uncertainty of the bypass flow rate is not known, some sources have stated that the bypass flow rates in the Fort St. Vrain reactor were between 8 and 25 percent of the total reactor mass flow rate. If bypass flow rates are on the

  9. Abnormal ionization in sonoluminescence

    NASA Astrophysics Data System (ADS)

    Zhang, Wen-Juan; An, Yu

    2015-04-01

    Sonoluminescence is a complex phenomenon, the mechanism of which remains unclear. The present study reveals that an abnormal ionization process is likely to be present in the sonoluminescing bubble. To fit the experimental data of previous studies, we assume that the ionization energies of the molecules and atoms in the bubble decrease as the gas density increases and that the decrease of the ionization energy reaches about 60%-70% as the bubble flashes, which is difficult to explain by using previous models. Project supported by the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120002110031) and the National Natural Science Foundation of China (Grant No. 11334005).

  10. Design and Implementation of a Characterization Test Rig for Evaluating High Bandwidth Liquid Fuel Flow Modulators

    NASA Technical Reports Server (NTRS)

    Saus, Joseph R.; Chang, Clarence T.; DeLaat, John C.; Vrnak, Daniel R.

    2010-01-01

    A test rig was designed and developed at the NASA Glenn Research Center (GRC) for the purpose of characterizing high bandwidth liquid fuel flow modulator candidates to determine their suitability for combustion instability control research. The test rig is capable of testing flow modulators at up to 600 psia supply pressure and flows of up to 2 gpm. The rig is designed to provide a quiescent flow into the test section in order to isolate the dynamic flow modulations produced by the test article. Both the fuel injector orifice downstream of the test article and the combustor are emulated. The effect of fuel delivery line lengths on modulator dynamic performance can be observed and modified to replicate actual fuel delivery systems. For simplicity, water is currently used as the working fluid, although future plans are to use jet fuel. The rig is instrumented for dynamic pressures and flows and a high-speed data system is used for dynamic data acquisition. Preliminary results have been obtained for one candidate flow modulator.

  11. Mathematical modeling of jet interaction with a high-enthalpy flow in an expanding channel

    NASA Astrophysics Data System (ADS)

    Fedorova, N. N.; Fedorchenko, I. A.; Fedorov, A. V.

    2013-03-01

    Results of modeling the interaction of a plane supersonic jet with a supersonic turbulent high-enthalpy flow in a channel are reported. The problem is solved in a two-dimensional formulation at external flow Mach numbers M∞ = 2.6 and 2.8 and at high values of the total temperature of the flow T 0 = 1800-2000 K. The mathematical model includes full averaged Navier-Stokes equations supplemented with a two-equation turbulence model and an equation that describes the transportation of the injected substance. The computations are performed by using the ANSYS Fluent 12.1 software package. Verification of the computational technique is performed against available experimental results on transverse injection of nitrogen and helium jets. The computed and experimental results are demonstrated to agree well. For the examined problems, in addition to surface distributions of characteristics, fields of flow parameters are obtained, which allow one to reproduce specific features that can be hardly captured in experiments. Parametric studies show that an increase in the angle of inclination and the mass flow rate of the jet leads to an increase in the depth of jet penetration into the flow, but more intense separated flows and shock waves are observed in this case.

  12. ZaP-HD: High Energy Density Z-Pinch Plasmas using Sheared Flow Stabilization

    NASA Astrophysics Data System (ADS)

    Golingo, R. P.; Shumlak, U.; Nelson, B. A.; Claveau, E. L.; Doty, S. A.; Forbes, E. G.; Hughes, M. C.; Kim, B.; Ross, M. P.; Weed, J. R.

    2015-11-01

    The ZaP-HD flow Z-pinch project investigates scaling the flow Z-pinch to High Energy Density Plasma, HEDP, conditions by using sheared flow stabilization. ZaP used a single power supply to produce 100 cm long Z-pinches that were quiescent for many radial Alfven times and axial flow-through times. The flow Z-pinch concept provides an approach to achieve HED plasmas, which are dimensionally large and persist for extended durations. The ZaP-HD device replaces the single power supply from ZaP with two separate power supplies to independently control the plasma flow and current in the Z-pinch. Equilibrium is determined by diagnostic measurements of the density with interferometry and digital holography, the plasma flow and temperature with passive spectroscopy, the magnetic field with surface magnetic probes, and plasma emission with optical imaging. The diagnostics fully characterize the plasma from its initiation in the coaxial accelerator, through the pinch, and exhaust from the assembly region. The plasma evolution is modeled with high resolution codes: Mach2, WARPX, and NIMROD. Experimental results and scaling analyses are presented. This work is supported by grants from the U.S. Department of Energy and the U.S. National Nuclear Security Administration.

  13. Depressurization and two-phase flow of water containing high levels of dissolved nitrogen gas

    NASA Technical Reports Server (NTRS)

    Simoneau, R. J.

    1981-01-01

    Depressurization of water containing various concentrations of dissolved nitrogen gas was studied. In a nonflow depressurization experiment, water with very high nitrogen content was depressurized at rates from 0.09 to 0.50 MPa per second and a metastable behavior which was a strong function of the depressurization rate was observed. Flow experiments were performed in an axisymmetric, converging diverging nozzle, a two dimensional, converging nozzle with glass sidewalls, and a sharp edge orifice. The converging diverging nozzle exhibited choked flow behavior even at nitrogen concentration levels as low as 4 percent of the saturation level. The flow rates were independent of concentration level. Flow in the two dimensional, converging, visual nozzle appeared to have a sufficient pressure drop at the throat to cause nitrogen to come out of solution, but choking occurred further downstream. The orifice flow motion pictures showed considerable oscillation downstream of the orifice and parallel to the flow. Nitrogen bubbles appeared in the flow at back pressures as high as 3.28 MPa, and the level at which bubbles were no longer visible was a function of nitrogen concentration.

  14. Synergistic effect of high-affinity binding and flow preconditioning on endothelial cell adhesion.

    PubMed

    Mathur, Anshu B; Truskey, George A; Reichert, William M

    2003-01-01

    The current study examined whether the combined introduction of high-affinity avidin-biotin bonds and fibronectin-integrin bonds (i.e., dual ligand treatment) would further augment the adhesion of flow-preconditioned endothelial cells to model substrates via contributions to the actin cytoskeleton and the formation of focal contacts. Human umbilical vein endothelial cells (HUVEC) were grown under static conditions or exposed to a flow-preconditioning regimen for 24 h. Cell retention was determined by exposure to 75 dynes/cm(2). The combination of flow preconditioning and the dual ligand treatment yielded higher cell retention under flow compared to the cells adherent via fibronectin-integrin bonds only. This increase in adhesion strength correlated with a greater focal contact area. Elongation of the HUVEC occurred after exposure to flow preconditioning; however, orientation of dual ligand adherent cells was restricted due to the presence of the high-affinity ligand. Flow-preconditioned cells showed increased stress fiber formation compared to nonconditioned cells although the stress fibers per cell for flow-preconditioned cells were the same on both the ligand systems employed. The results indicate that enhanced adhesion strength is due to a combination of increased focal contact area, stress fiber formation, and cell alignment. PMID:12483708

  15. Discrete vortex model of a Helmholtz resonator subjected to high-intensity sound and grazing flow.

    PubMed

    Dai, Xiwen; Jing, Xiaodong; Sun, Xiaofeng

    2012-11-01

    In this paper, a theoretical model is developed to study the acoustical response of a Helmholtz resonator as a duct-branched acoustic absorber subjected to both high-intensity sound and grazing flow. The present model is comprised of a discrete vortex model in combination with a one-dimensional duct sound propagation model. The present work is to study the overall effect of incident sound interacting with grazing flow but putting emphasis on the nonlinear or intermediate regime where the sound intensity has a marked or non-negligible influence on the acoustic behavior of the Helmholtz resonator. The numerical results reveal that the flow field around the orifice is dominated by the evolution of the vortex sheet and the flow pattern is influenced by the ratio of the orifice flow velocity to the grazing flow velocity. When the incident sound pressure is high or the resonance occurs, the resonator shows nonlinearity, i.e., the acoustic impedance and absorption coefficient vary not only with duct flow Mach number buy also with incident frequency and incident sound pressure level.

  16. Visualization of Secondary Flow Development in High Aspect Ratio Channels with Curvature

    NASA Technical Reports Server (NTRS)

    Meyer, Michael L.; Giuliani, James E.

    1994-01-01

    The results of an experimental project to visually examine the secondary flow structure that develops in curved, high aspect-ratio rectangular channels are presented. The results provide insight into the fluid dynamics within high aspect ratio channels. A water flow test rig constructed out of plexiglass, with an adjustable aspect ratio, was used for these experiments. Results were obtained for a channel geometry with a hydraulic diameter of 10.6 mm (0.417 in.), an aspect ratio of 5.0, and a hydraulic radius to curvature radius ratio of 0.0417. Flow conditions were varied to achieve Reynolds numbers up to 5,100. A new particle imaging velocimetry technique was developed which could resolve velocity information from particles entering and leaving the field of view. Time averaged secondary flow velocity vectors, obtained using this velocimetry technique, are presented for 30 degrees, 60 degrees, and 90 degrees into a 180 degrees bend and at a Reynolds number of 5,100. The secondary flow results suggest the coexistence of both the classical curvature induced vortex pair flow structure and the eddies seen in straight turbulent channel flow.

  17. Lack of Evidence for Regional Brain Volume or Cortical Thickness Abnormalities in Youths at Clinical High Risk for Psychosis: Findings From the Longitudinal Youth at Risk Study.

    PubMed

    Klauser, Paul; Zhou, Juan; Lim, Joseph K W; Poh, Joann S; Zheng, Hui; Tng, Han Ying; Krishnan, Ranga; Lee, Jimmy; Keefe, Richard S E; Adcock, R Alison; Wood, Stephen J; Fornito, Alex; Chee, Michael W L

    2015-11-01

    There is cumulative evidence that young people in an "at-risk mental state" (ARMS) for psychosis show structural brain abnormalities in frontolimbic areas, comparable to, but less extensive than those reported in established schizophrenia. However, most available data come from ARMS samples from Australia, Europe, and North America while large studies from other populations are missing. We conducted a structural brain magnetic resonance imaging study from a relatively large sample of 69 ARMS individuals and 32 matched healthy controls (HC) recruited from Singapore as part of the Longitudinal Youth At-Risk Study (LYRIKS). We used 2 complementary approaches: a voxel-based morphometry and a surface-based morphometry analysis to extract regional gray and white matter volumes (GMV and WMV) and cortical thickness (CT). At the whole-brain level, we did not find any statistically significant difference between ARMS and HC groups concerning total GMV and WMV or regional GMV, WMV, and CT. The additional comparison of 2 regions of interest, hippocampal, and ventricular volumes, did not return any significant difference either. Several characteristics of the LYRIKS sample like Asian origins or the absence of current illicit drug use could explain, alone or in conjunction, the negative findings and suggest that there may be no dramatic volumetric or CT abnormalities in ARMS. PMID:25745033

  18. Multichannel readout ASIC design flow for high energy physics and cosmic rays experiments

    NASA Astrophysics Data System (ADS)

    Voronin, A.; Malankin, E.

    2016-02-01

    In the large-scale high energy physics and astrophysics experiments multi-channel readout application specific integrated circuits (ASICs) are widely used. The ASICs for such experiments are complicated systems, which usually include both analog and digital building blocks. The complexity and large number of channels in such ASICs require the proper methodological approach to their design. The paper represents the mixed-signal design flow of the ASICs for high energy physics and cosmic rays experiments. This flow was successfully embedded to the development of the read-out ASIC prototype for the muon chambers of the CBM experiment. The approach was approved in UMC CMOS MMRF 180 nm process. The design flow enable to analyse the mixed-signal system operation on the different levels: functional, behavioural, schematic and post layout including parasitic elements. The proposed design flow allows reducing the simulation period and eliminating the functionality mismatches on the very early stage of the design.

  19. Effects of High-Intensity Blood Flow Restriction Exercise on Muscle Fatigue

    PubMed Central

    Neto, Gabriel R.; Santos, Heleodório H.; Sousa, Juliana B. C.; Júnior, Adenilson T. A.; Araújo, Joamira P.; Aniceto, Rodrigo R.; Sousa, Maria S. C.

    2014-01-01

    Strength training combined with blood flow restriction (BFR) have been used to improve the levels of muscle adaptation. The aim of this paper was to investigate the acute effect of high intensity squats with and without blood flow restriction on muscular fatigue levels. Twelve athletes (aged 25.95 ± 0.84 years) were randomized into two groups: without Blood Flow Restriction (NFR, n = 6) and With Blood Flow Restriction (WFR, n = 6) that performed a series of free weight squats with 80% 1-RM until concentric failure. The strength of the quadriceps extensors was assessed in a maximum voluntary isometric contraction integrated to signals from the surface electromyogram. The average frequency showed significant reductions in the WFR group for the vastus lateralis and vastus medialis muscles, and intergroup only for the vastus medialis. In conclusion, a set of squats at high intensity with BFR could compromise muscle strength immediately after exercise, however, differences were not significant between groups. PMID:25114743

  20. Modeling highly transient flow, mass, and heat transport in the Chattahoochee River near Atlanta, Georgia

    USGS Publications Warehouse

    Jobson, Harvey E.; Keefer, Thomas N.

    1979-01-01

    A coupled flow-temperature model has been developed and verified for a 27.9-km reach of the Chattahoochee River between Buford Dam and Norcross, Ga. Flow in this reach of the Chattahoochee is continuous but highly regulated by Buford Dam, a flood-control and hydroelectric facility located near Buford, Ga. Calibration and verification utilized two sets of data collected under highly unsteady discharge conditions. Existing solution techniques, with certain minor improvements, were applied to verify the existing technology of flow and transport modeling. A linear, implicit finite-difference flow model was coupled with implicit, finite-difference transport and temperature models. Both the conservative and nonconservative forms of the transport equation were solved, and the difference in the predicted concentrations of dye were found to be insignificant. The temperature model, therefore, was based on the simpler nonconservative form of the transport equation. (Woodard-USGS)

  1. Aerodynamic study on supersonic flows in high-velocity oxy-fuel thermal spray process

    NASA Astrophysics Data System (ADS)

    Katanoda, Hiroshi; Matsuoka, Takeshi; Kuroda, Seiji; Kawakita, Jin; Fukanuma, Hirotaka; Matsuo, Kazuyasu

    2005-06-01

    To clarify the characteristics of gas flow in high velocity oxy-fuel (HVOF) thermal spray gun, aerodynamic research is performed using a special gun. The gun has rectangular cross-sectional area and sidewalls of optical glass to visualize the internal flow. The gun consists of a supersonic nozzle with the design Mach number of 2.0 followed by a straight passage called barrel. Compressed dry air up to 0.78 MPa is used as a process gas instead of combustion gas which is used in a commercial HVOF gun. The high-speed gas flows with shock waves in the gun and jets are visualized by schlieren technique. Complicated internal and external flow-fields containing various types of shock wave as well as expansion wave are visualized.

  2. Hydrodynamic chromatography using flow of a highly concentrated dextran solution through a coiled tube.

    PubMed

    Miyagawa, Yoichi; Morisada, Shintaro; Ohto, Keisuke; Hidetaka, Kawakita

    2016-08-01

    Separation of colloidal particles in non-Newtonian fluid is important in food engineering. Using hydrodynamic chromatography, colloidal particles and starch granules originating from corn were individually injected into dextran solutions (Mw 2,000,000g/mol) flowing through a coiled tube for efficient size separation. Rheological properties of dextran solutions ranging from 50 to 250g/L were determined, revealing pseudoplastic fluid behavior. Velocity profiles for dextran solution flow in coiled tubes were obtained from rheological power law parameters. Suspensions of colloidal particles of diameters 1.0 and 20μm were individually injected into the dextran flows, demonstrating that dextran solutions at high concentration separated colloidal particles. Starch granules were separated by size using a dextran solution flow (250g/L). Thus, we expect to obtain efficient separation of colloidal particles in foods using highly concentrated dextran solutions. PMID:27112856

  3. A numerical study of the controlled flow tunnel for a high lift model

    NASA Technical Reports Server (NTRS)

    Parikh, P. C.

    1984-01-01

    A controlled flow tunnel employs active control of flow through the walls of the wind tunnel so that the model is in approximately free air conditions during the test. This improves the wind tunnel test environment, enhancing the validity of the experimentally obtained test data. This concept is applied to a three dimensional jet flapped wing with full span jet flap. It is shown that a special treatment is required for the high energy wake associated with this and other V/STOL models. An iterative numerical scheme is developed to describe the working of an actual controlled flow tunnel and comparisons are shown with other available results. It is shown that control need be exerted over only part of the tunnel walls to closely approximate free air flow conditions. It is concluded that such a tunnel is able to produce a nearly interference free test environment even with a high lift model in the tunnel.

  4. Nearly Interactive Parabolized Navier-Stokes Solver for High Speed Forebody and Inlet Flows

    NASA Technical Reports Server (NTRS)

    Benson, Thomas J.; Liou, May-Fun; Jones, William H.; Trefny, Charles J.

    2009-01-01

    A system of computer programs is being developed for the preliminary design of high speed inlets and forebodies. The system comprises four functions: geometry definition, flow grid generation, flow solver, and graphics post-processor. The system runs on a dedicated personal computer using the Windows operating system and is controlled by graphical user interfaces written in MATLAB (The Mathworks, Inc.). The flow solver uses the Parabolized Navier-Stokes equations to compute millions of mesh points in several minutes. Sample two-dimensional and three-dimensional calculations are demonstrated in the paper.

  5. Theoretical analysis of the ultrasonic Doppler flowmeter for measurements of high flow velocities

    NASA Astrophysics Data System (ADS)

    Tabin, Jozef

    1987-07-01

    A geometric approach is used to analyze the ultrasonic Doppler flowmeter for measurements of flow velocities that are high but yet much smaller than the ultrasound velocity. The approach is based on the calculation of the transit time difference between the ultrasonic waves that are reflected from a moving particle at its various positions. Beam divergence is taken into account, and each path of the ultrasonic wave propagation is approximated by two rectilinear components. It is shown that the Doppler frequency shift is influenced not only by the suspended particle velocity, but also by the mean flow velocity of the fluid. This influence is of second order in the flow velocity.

  6. Rapid, high-order accurate calculation of flows due to free source or vortex distributions

    NASA Technical Reports Server (NTRS)

    Halsey, D.

    1981-01-01

    Fast Fourier transform (FFT) techniques are applied to the problem of finding the flow due to source or vortex distributions in the field outside an airfoil or other two-dimensional body. Either the complex potential or the complex velocity may be obtained to a high order of accuracy, with computational effort similar to that required by second-order fast Poisson solvers. These techniques are applicable to general flow problems with compressibility and rotation. An example is given of their use for inviscid compressible flow.

  7. LES, DNS and RANS for the analysis of high-speed turbulent reacting flows

    NASA Technical Reports Server (NTRS)

    Adumitroaie, V.; Colucci, P. J.; Taulbee, D. B.; Givi, P.

    1995-01-01

    The purpose of this research is to continue our efforts in advancing the state of knowledge in large eddy simulation (LES), direct numerical simulation (DNS), and Reynolds averaged Navier Stokes (RANS) methods for the computational analysis of high-speed reacting turbulent flows. In the second phase of this work, covering the period 1 Aug. 1994 - 31 Jul. 1995, we have focused our efforts on two programs: (1) developments of explicit algebraic moment closures for statistical descriptions of compressible reacting flows and (2) development of Monte Carlo numerical methods for LES of chemically reacting flows.

  8. Computation of Space Shuttle high-pressure cryogenic turbopump ball bearing two-phase coolant flow

    NASA Technical Reports Server (NTRS)

    Chen, Yen-Sen

    1990-01-01

    A homogeneous two-phase fluid flow model, implemented in a three-dimensional Navier-Stokes solver using computational fluid dynamics methodology is described. The application of the model to the analysis of the pump-end bearing coolant flow of the high-pressure oxygen turbopump of the Space Shuttle main engine is studied. Results indicate large boiling zones and hot spots near the ball/race contact points. The extent of the phase change of the liquid oxygen coolant flow due to the frictional and viscous heat fluxes near the contact areas has been investigated for the given inlet conditions of the coolant.

  9. High-speed holocinematographic velocimeter for studying turbulent flow control physics

    NASA Technical Reports Server (NTRS)

    Weinstein, L. M.; Beeler, G. B.; Lindemann, A. M.

    1985-01-01

    Use of a dual view, high speed, holographic movie technique is examined for studying turbulent flow control physics. This approach, which eliminates some of the limitations of previous holographic techniques, is termed a holocinematographic velocimeter (HCV). The data from this system can be used to check theoretical turbulence modeling and numerical simulations, visualize and measure coherent structures in 'non-simple' turbulent flows, and examine the mechanisms operative in various turbulent control/drag reduction concepts. This system shows promise for giving the most complete experimental characterization of turbulent flows yet available.

  10. Abnormal hematological indices in cirrhosis

    PubMed Central

    Qamar, Amir A; Grace, Norman D

    2009-01-01

    Abnormalities in hematological indices are frequently encountered in cirrhosis. Multiple causes contribute to the occurrence of hematological abnormalities. Recent studies suggest that the presence of hematological cytopenias is associated with a poor prognosis in cirrhosis. The present article reviews the pathogenesis, incidence, prevalence, clinical significance and treatment of abnormal hematological indices in cirrhosis. PMID:19543577

  11. Abnormalities of polymorphonuclear leukocyte function associated with a heritable deficiency of high molecular weight surface glycoproteins (GP138): common relationship to diminished cell adherence.

    PubMed Central

    Anderson, D C; Schmalstieg, F C; Arnaout, M A; Kohl, S; Tosi, M F; Dana, N; Buffone, G J; Hughes, B J; Brinkley, B R; Dickey, W D

    1984-01-01

    Investigations of polymorphonuclear leukocyte (PMN) function were performed in a 5-yr-old white female with delayed umbilical cord separation, impaired pus formation, and a severe defect of PMN chemotaxis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated an almost total deficiency of a high molecular weight glycoprotein(s) (GP138) in the granule and membrane fractions of the patient's cells, and NaB3H4-galactose oxidase labeling demonstrated the absence of a major glycoprotein complex on the surface of her PMNs. Monoclonal antibodies (MAb) were employed in flow cytometry experiments to demonstrate that two previously characterized glycoproteins (Mo1 and LFA1) were undetectable on the surface of the patient's PMNs and monocytes. Immunoprecipitation of 125I-labeled patient cells with subunit specific MAbs confirmed that the alpha-subunits of Mo1 (155 kD) and LFA1 (177 kD) and their common beta-subunit (94 kD) were totally deficient. Functional analyses of patient PMNs demonstrated severe impairment of adherence- and adhesion-dependent cell functions including spreading, aggregation, orientation in chemotactic gradients, antibody-dependent cellular cytotoxicity, and phagocytosis of particles (Oil-Red-0-paraffin, zymosan) selectively opsonized with C3-derived ligands. Patient PMNs demonstrated a normal capacity to rosette with IgG or C3b-coated sheep erythrocytes, but rosette formation with C3bi-coated erythrocytes was profoundly diminished. Adhesion-independent functions including shape change, N-formyl-methionyl-leucyl-3H-phenylalanine binding, and O-2 generation or secretion elicited by soluble stimuli were normal. Membrane fluidity, surface charge, and microtubule assembly were also normal. These findings provide new evidence that critical PMN surface glycoproteins are required to facilitate multiple adhesion-dependent cellular functions of the inflammatory response. Images PMID:6746906

  12. Application of PIV to the Measurement of High Speed Jet Flows

    NASA Technical Reports Server (NTRS)

    Lourenco, L.

    1999-01-01

    The Particle Image Velocimetry, PIV, has been implemented for the investigation of high-speed jet flows at the NASA Langley Research Center. In this approach the velocity (displacement) is found as the location of a peak in the correlation map of particle images acquired in quick succession. In the study, the technique for the correct seeding of the flow field were developed and implemented and the operational parameters influencing the accuracy of the measurement have been optimized.

  13. Performance of Improved High-Order Filter Schemes for Turbulent Flows with Shocks

    NASA Technical Reports Server (NTRS)

    Kotov, Dmitry Vladimirovich; Yee, Helen M C.

    2013-01-01

    The performance of the filter scheme with improved dissipation control ? has been demonstrated for different flow types. The scheme with local ? is shown to obtain more accurate results than its counterparts with global or constant ?. At the same time no additional tuning is needed to achieve high accuracy of the method when using the local ? technique. However, further improvement of the method might be needed for even more complex and/or extreme flows.

  14. High-flow priapism: a novel way of lateralizing the lesion in radiologically inapparent cases.

    PubMed

    Ankem, M K; Gazi, M A; Ferlise, V J; Hartanto, V H; Doshi, N M; Diamond, S M

    2001-04-01

    High-flow priapism is a rare entity, which is typically diagnosed with the help of either color flow Doppler ultrasound or arteriogram. In the case presented, both of these diagnostic modalities were unsuccessful in uncovering a vascular lesion. The patient underwent an empiric selective embolization of the left pudendal artery followed by a repeat angiogram of the right because of persistent tumescence. This procedure uncovered a previously unseen arteriolacunar fistula, which was treated successfully with a second selective embolization.

  15. Study and application of a high-pressure water jet multi-functional flow test system.

    PubMed

    Shi, Huaizhong; Li, Gensheng; Huang, Zhongwei; Li, Jingbin; Zhang, Yi

    2015-12-01

    As the exploration and development of oil and gas focus more and more on deeper formation, hydraulic issues such as high-pressure water jet rock breaking, wellbore multiphase flow law, cuttings carrying efficiency, and hydraulic fracturing technique during the drilling and completion process have become the key points. To accomplish related researches, a high-pressure water jet multi-functional flow test system was designed. The following novel researches are carried out: study of high-pressure water jet characteristics under confining pressure, wellbore multiphase flow regime, hydraulic pressure properties of down hole tools during jet fracturing and pulsed cavitation jet drilling, and deflector's friction in radial jet drilling. The validity and feasibility of the experimental results provided by the system with various test modules have proved its importance in the research of the high-pressure water jet and well completion technology. PMID:26724077

  16. Unstructured and adaptive mesh generation for high Reynolds number viscous flows

    NASA Technical Reports Server (NTRS)

    Mavriplis, Dimitri J.

    1991-01-01

    A method for generating and adaptively refining a highly stretched unstructured mesh suitable for the computation of high-Reynolds-number viscous flows about arbitrary two-dimensional geometries was developed. The method is based on the Delaunay triangulation of a predetermined set of points and employs a local mapping in order to achieve the high stretching rates required in the boundary-layer and wake regions. The initial mesh-point distribution is determined in a geometry-adaptive manner which clusters points in regions of high curvature and sharp corners. Adaptive mesh refinement is achieved by adding new points in regions of large flow gradients, and locally retriangulating; thus, obviating the need for global mesh regeneration. Initial and adapted meshes about complex multi-element airfoil geometries are shown and compressible flow solutions are computed on these meshes.

  17. Study and application of a high-pressure water jet multi-functional flow test system.

    PubMed

    Shi, Huaizhong; Li, Gensheng; Huang, Zhongwei; Li, Jingbin; Zhang, Yi

    2015-12-01

    As the exploration and development of oil and gas focus more and more on deeper formation, hydraulic issues such as high-pressure water jet rock breaking, wellbore multiphase flow law, cuttings carrying efficiency, and hydraulic fracturing technique during the drilling and completion process have become the key points. To accomplish related researches, a high-pressure water jet multi-functional flow test system was designed. The following novel researches are carried out: study of high-pressure water jet characteristics under confining pressure, wellbore multiphase flow regime, hydraulic pressure properties of down hole tools during jet fracturing and pulsed cavitation jet drilling, and deflector's friction in radial jet drilling. The validity and feasibility of the experimental results provided by the system with various test modules have proved its importance in the research of the high-pressure water jet and well completion technology.

  18. Study and application of a high-pressure water jet multi-functional flow test system

    NASA Astrophysics Data System (ADS)

    Shi, Huaizhong; Li, Gensheng; Huang, Zhongwei; Li, Jingbin; Zhang, Yi

    2015-12-01

    As the exploration and development of oil and gas focus more and more on deeper formation, hydraulic issues such as high-pressure water jet rock breaking, wellbore multiphase flow law, cuttings carrying efficiency, and hydraulic fracturing technique during the drilling and completion process have become the key points. To accomplish related researches, a high-pressure water jet multi-functional flow test system was designed. The following novel researches are carried out: study of high-pressure water jet characteristics under confining pressure, wellbore multiphase flow regime, hydraulic pressure properties of down hole tools during jet fracturing and pulsed cavitation jet drilling, and deflector's friction in radial jet drilling. The validity and feasibility of the experimental results provided by the system with various test modules have proved its importance in the research of the high-pressure water jet and well completion technology.

  19. Effects of Unsteady Flow Interactions on the Performance of a Highly-Loaded Transonic Compressor Stage

    NASA Technical Reports Server (NTRS)

    Hah, Chunill

    2015-01-01

    Effects of unsteady flow interactions on the aerodynamic performance of a highly-loaded transonic axial compressor are investigated in the present study. The primary focus of the study is to investigate how unsteady flow interactions between blade rows affect the aerodynamic performance of a highly-loaded transonic axial compressor. Recent experimental and numerical studies of current highly-loaded axial compressor performance indicated that predicting calculating the loss generation is very challenging with various analysis tools. In the present study, the effects of generation and transport of shock induced vortices on the compressor performance is investigated in detail.

  20. High-order lattice Boltzmann models for wall-bounded flows at finite Knudsen numbers.

    PubMed

    Feuchter, C; Schleifenbaum, W

    2016-07-01

    We analyze a large number of high-order discrete velocity models for solving the Boltzmann-Bhatnagar-Gross-Krook equation for finite Knudsen number flows. Using the Chapman-Enskog formalism, we prove for isothermal flows a relation identifying the resolved flow regimes for low Mach numbers. Although high-order lattice Boltzmann models recover flow regimes beyond the Navier-Stokes level, we observe for several models significant deviations from reference results. We found this to be caused by their inability to recover the Maxwell boundary condition exactly. By using supplementary conditions for the gas-surface interaction it is shown how to systematically generate discrete velocity models of any order with the inherent ability to fulfill the diffuse Maxwell boundary condition accurately. Both high-order quadratures and an exact representation of the boundary condition turn out to be crucial for achieving reliable results. For Poiseuille flow, we can reproduce the mass flow and slip velocity up to the Knudsen number of 1. Moreover, for small Knudsen numbers, the Knudsen layer behavior is recovered. PMID:27575233

  1. True color blood flow imaging using a high-speed laser photography system

    NASA Astrophysics Data System (ADS)

    Liu, Chien-Sheng; Lin, Cheng-Hsien; Sun, Yung-Nien; Ho, Chung-Liang; Hsu, Chung-Chi

    2012-10-01

    Physiological changes in the retinal vasculature are commonly indicative of such disorders as diabetic retinopathy, glaucoma, and age-related macular degeneration. Thus, various methods have been developed for noninvasive clinical evaluation of ocular hemodynamics. However, to the best of our knowledge, current ophthalmic instruments do not provide a true color blood flow imaging capability. Accordingly, we propose a new method for the true color imaging of blood flow using a high-speed pulsed laser photography system. In the proposed approach, monochromatic images of the blood flow are acquired using a system of three cameras and three color lasers (red, green, and blue). A high-quality true color image of the blood flow is obtained by assembling the monochromatic images by means of image realignment and color calibration processes. The effectiveness of the proposed approach is demonstrated by imaging the flow of mouse blood within a microfluidic channel device. The experimental results confirm the proposed system provides a high-quality true color blood flow imaging capability, and therefore has potential for noninvasive clinical evaluation of ocular hemodynamics.

  2. Hemodynamic Study of Flow Remodeling Stent Graft for the Treatment of Highly Angulated Abdominal Aortic Aneurysm

    PubMed Central

    Yeow, Siang Lin; Leo, Hwa Liang

    2016-01-01

    This study investigates the effect of a novel flow remodeling stent graft (FRSG) on the hemodynamic characteristics in highly angulated abdominal aortic aneurysm based on computational fluid dynamics (CFD) approach. An idealized aortic aneurysm with varying aortic neck angulations was constructed and CFD simulations were performed on nonstented models and stented models with FRSG. The influence of FRSG intervention on the hemodynamic performance is analyzed and compared in terms of flow patterns, wall shear stress (WSS), and pressure distribution in the aneurysm. The findings showed that aortic neck angulations significantly influence the velocity flow field in nonstented models, with larger angulations shifting the mainstream blood flow towards the center of the aorta. By introducing FRSG treatment into the aneurysm, erratic flow recirculation pattern in the aneurysm sac diminishes while the average velocity magnitude in the aneurysm sac was reduced in the range of 39% to 53%. FRSG intervention protects the aneurysm against the impacts of high velocity concentrated flow and decreases wall shear stress by more than 50%. The simulation results highlighted that FRSG may effectively treat aneurysm with high aortic neck angulations via the mechanism of promoting thrombus formation and subsequently led to the resorption of the aneurysm. PMID:27247612

  3. High-order lattice Boltzmann models for wall-bounded flows at finite Knudsen numbers

    NASA Astrophysics Data System (ADS)

    Feuchter, C.; Schleifenbaum, W.

    2016-07-01

    We analyze a large number of high-order discrete velocity models for solving the Boltzmann-Bhatnagar-Gross-Krook equation for finite Knudsen number flows. Using the Chapman-Enskog formalism, we prove for isothermal flows a relation identifying the resolved flow regimes for low Mach numbers. Although high-order lattice Boltzmann models recover flow regimes beyond the Navier-Stokes level, we observe for several models significant deviations from reference results. We found this to be caused by their inability to recover the Maxwell boundary condition exactly. By using supplementary conditions for the gas-surface interaction it is shown how to systematically generate discrete velocity models of any order with the inherent ability to fulfill the diffuse Maxwell boundary condition accurately. Both high-order quadratures and an exact representation of the boundary condition turn out to be crucial for achieving reliable results. For Poiseuille flow, we can reproduce the mass flow and slip velocity up to the Knudsen number of 1. Moreover, for small Knudsen numbers, the Knudsen layer behavior is recovered.

  4. Spirometric abnormalities among welders

    SciTech Connect

    Rastogi, S.K.; Gupta, B.N.; Husain, T.; Mathur, N.; Srivastava, S. )

    1991-10-01

    A group of manual welders age group 13-60 years having a mean exposure period of 12.4 {plus minus} 1.12 years were subjected to spirometry to evaluate the prevalence of spirometric abnormalities. The welders showed a significantly higher prevalence of respiratory impairment than that observed among the unexposed controls as a result of exposure to welding gases which comprised fine particles of lead, zinc, chromium, and manganese. This occurred despite the lower concentration of the pollutants at the work place. In the expose group, the smoking welders showed a prevalence of respiratory impairment significantly higher than that observed in the nonsmoking welders. The results of the pulmonary function tests showed a predominantly restrictive type of pulmonary impairment followed by a mixed ventilatory defect among the welders. The effect of age on pulmonary impairment was not discernible. Welders exposed for over 10 years showed a prevalence of respiratory abnormalities significantly higher than those exposed for less than 10 years. Smoking also had a contributory role.

  5. Flow-Visualization Techniques Used at High Speed by Configuration Aerodynamics Wind-Tunnel-Test Team

    NASA Technical Reports Server (NTRS)

    Lamar, John E. (Editor)

    2001-01-01

    This paper summarizes a variety of optically based flow-visualization techniques used for high-speed research by the Configuration Aerodynamics Wind-Tunnel Test Team of the High-Speed Research Program during its tenure. The work of other national experts is included for completeness. Details of each technique with applications and status in various national wind tunnels are given.

  6. High School Physical Education: What Contributes to the Experience of Flow?

    ERIC Educational Resources Information Center

    Stormoen, Sidsel; Urke, Helga Bjørnøy; Tjomsland, Hege Eikeland; Wold, Bente; Diseth, Åge

    2016-01-01

    This study seeks to identify factors that promote positive experiences in high school physical education (PE). The study combines elements of Self-determination Theory (SDT) with the theory of "flow". Special attention is given to gender differences. The study sample consisted of 167 Norwegian senior high school students (78 females and…

  7. High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

    NASA Astrophysics Data System (ADS)

    Villagómez-Hoyos, Carlos A.; Stuart, Matthias B.; Bechsgaard, Thor; Nielsen, Michael Bachmann; Jensen, Jørgen Arendt

    2016-04-01

    This work presents the first in vivo results of 2-D high frame rate vector velocity imaging for transthoracic cardiac imaging. Measurements are made on a healthy volunteer using the SARUS experimental ultrasound scanner connected to an intercostal phased-array probe. Two parasternal long-axis view (PLAX) are obtained, one centred at the aortic valve and another centred at the left ventricle. The acquisition sequence was composed of 3 diverging waves for high frame rate synthetic aperture flow imaging. For verification a phantom measurement is performed on a transverse straight 5 mm diameter vessel at a depth of 100 mm in a tissue-mimicking phantom. A flow pump produced a 2 ml/s constant flow with a peak velocity of 0.2 m/s. The average estimated flow angle in the ROI was 86.22° +/- 6.66° with a true flow angle of 90°. A relative velocity bias of -39% with a standard deviation of 13% was found. In-vivo acquisitions show complex flow patterns in the heart. In the aortic valve view, blood is seen exiting the left ventricle cavity through the aortic valve into the aorta during the systolic phase of the cardiac cycle. In the left ventricle view, blood flow is seen entering the left ventricle cavity through the mitral valve and splitting in two ways when approximating the left ventricle wall. The work presents 2-D velocity estimates on the heart from a non-invasive transthoracic scan. The ability of the method detecting flow regardless of the beam angle could potentially reveal a more complete view of the flow patterns presented on the heart.

  8. High Intracranial Pressure Effects on Cerebral Cortical Microvascular Flow in Rats

    PubMed Central

    Bush, Rachel C.; Müller, Wolfgang S.; Nemoto, Edwin M.

    2011-01-01

    Abstract To manage patients with high intracranial pressure (ICP), clinicians need to know the critical cerebral perfusion pressure (CPP) required to maintain cerebral blood flow (CBF). Historically, the critical CPP obtained by decreasing mean arterial pressure (MAP) to lower CPP was 60 mm Hg, which fell to 30 mm Hg when CPP was reduced by increasing ICP. We examined whether this decrease in critical CPP was due to a pathological shift from capillary (CAP) to high-velocity microvessel flow or thoroughfare channel (TFC) shunt flow. Cortical microvessel red blood cell velocity and NADH fluorescence were measured by in vivo two-photon laser scanning microscopy in rats at CPP of 70, 50, and 30 mm Hg by increasing ICP or decreasing MAP. Water content was measured by wet/dry weight, and cortical perfusion by laser Doppler flux. Reduction of CPP by raising ICP increased TFC shunt flow from 30.4±2.3% to 51.2±5.2% (mean±SEM, p<0.001), NADH increased by 20.3±6.8% and 58.1±8.2% (p<0.01), and brain water content from 72.9±0.47% to 77.8±2.42% (p<0.01). Decreasing CPP by MAP decreased TFC shunt flow with a smaller rise in NADH and no edema. Doppler flux decreased less with increasing ICP than decreasing MAP. The decrease seen in the critical CPP with increased ICP is likely due to a redistribution of microvascular flow from capillary to microvascular shunt flow or TFC shunt flow, resulting in a pathologically elevated CBF associated with tissue hypoxia and brain edema, characteristic of non-nutritive shunt flow. PMID:21395499

  9. Final results of bilateral comparison between NIST and PTB for flows of high pressure natural gas

    NASA Astrophysics Data System (ADS)

    Mickan, B.; Toebben, H.; Johnson, A.; Kegel, T.

    2013-01-01

    In 2009 NIST developed a US national flow standard to provide traceability for flow meters used for custody transfer of pipeline quality natural gas. NIST disseminates the SI unit of flow by calibrating a customer flow meter against a parallel array of turbine meter working standards, which in turn are traceable to a pressure-volume-temperature-time (PVTt) primary standard. The calibration flow range extends from 0.125 actual m3/s to 9 actual m3/s with an expanded uncertainty as low as 0.22% at high flows, and increasing to almost 0.40% at the lowest flows. Details regarding the traceability chain and uncertainty analysis are documented in prior publications. The current manuscript verifies NIST's calibration uncertainty via a bilateral comparison with the German National Metrology Institute PTB. The results of the bilateral are linked to the 2006 key comparison results between three EURAMET national metrology institutes (i.e., PTB, VSL and LNE). Linkage is accomplished in spite of using a different transfer standard in the bilateral versus the key comparison. A mathematical proof is included that demonstrates that the relative difference between a laboratory's measured flow and the key comparison reference value is independent of the transfer package for most flow measurement applications. The bilateral results demonstrate that NIST's natural gas flow measurements are within their specified uncertainties and are equivalent to those of the EURAMET National Metrology Institutes. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  10. Ultra high bypass Nacelle aerodynamics inlet flow-through high angle of attack distortion test

    NASA Technical Reports Server (NTRS)

    Larkin, Michael J.; Schweiger, Paul S.

    1992-01-01

    A flow-through inlet test program was conducted to evaluate inlet test methods and determine the impact of the fan on inlet separation when operating at large angles of attack. A total of 16 model configurations of approximately 1/6 scale were tested. A comparison of these flow-through results with powered data indicates the presence of the fan increased separation operation 3 degrees to 4 degrees over the flow through inlet. Rods and screens located at the fan face station, that redistribute the flow, achieved simulation of the powered-fan results for separation angle of attack. Concepts to reduce inlet distortion and increase angle of attack capability were also evaluated. Vortex generators located on the inlet surface increased inlet angle of attack capability up to 2 degrees and reduced inlet distortion in the separated region. Finally, a method of simulating the fan/inlet aerodynamic interaction using blockage sizing method has been defined. With this method, a static blockage device used with a flow-through model will approximate the same inlet onset of separation angle of attack and distortion pattern that would be obtained with an inlet model containing a powered fan.

  11. Fifty probands with extra structurally abnormal chromosomes characterized by fluorescence in situ hybridization

    SciTech Connect

    Blennow, E.; Telenius, H.; Nordenskjoeld, M.

    1995-01-02

    Extra structurally abnormal chromosomes (ESACs) are small supernumerary chromosomes often associated with developmental abnormalities and malformations. We present 50 probands with ESACs characterized by fluorescence in situ hybridization using centromere-specific probes and chromosome-specific libraries. ESAC-specific libraries were constructed by flow sorting and subsequent amplification by DOP-PCR. Using such ESAC-specific libraries we were able to outline the chromosome regions involved. Twenty-three of the 50 ESACs were inverted duplications of chromosome 15 (inv dup(15)), including patients with normal phenotypes and others with similar clinical symptoms. These 2 groups differed in size and shape of the inv dup(15). Patients with a large inv dup(15), which included the Prader-Willi region, had a high risk of abnormality, whereas patients with a small inv dup(15), not including the Prader-Willi region, were normal. ESACs derived from chromosomes 13 or 21 appeared to have a low risk of abnormality, while one out of 3 patients with an ESAC derived from chromosome 14 had discrete symptoms. One out of 3 patients with an ESAC derived from chromosome 22 had severe anomalies, corresponding to some of the manifestations of the cat eye syndrome. Small extra ring chromosomes of autosomal origin and ESACs identified as i(12p) or i(18p) were all associated with a high risk of abnormality. 42 refs., 2 figs., 2 tabs.

  12. Comparison of PapType to Digene Hybrid Capture 2, Roche linear array, and Amplicor for detection of high-risk human papillomavirus genotypes in women with previous abnormal pap smears.

    PubMed

    Tabrizi, Sepehr N; Stevens, Matthew P; Khan, Zaheer A; Chow, Conan; Devitt, Martin A; Garland, Suzanne M

    2012-08-01

    PapType human papillomavirus (HPV) assay was compared to Hybrid Capture 2 (HC2), Amplicor (Amp), and Linear Array (LA) HPV tests in 894 women undergoing management for a high-grade Pap smear abnormality. The sensitivity in detection of underlying high-grade histological diagnosis by PapType was 90.3% and by HC2 was 79.8%, while by Amp and LA it was 92.4% and 91.6%, respectively. The specificities were 52.5%, 55.3%, 49.4%, and 51.7% for PapType, HC2, Amp, and LA, respectively.

  13. Prevalence of asymptomatic urinary abnormalities among adolescents.

    PubMed

    Fouad, Mohamed; Boraie, Maher

    2016-05-01

    To determine the prevalence of asymptomatic urinary abnormalities in adolescents, first morning clean mid-stream urine specimens were obtained from 2500 individuals and examined by dipstick and light microscopy. Adolescents with abnormal screening results were reexamined after two weeks and those who had abnormal results twice were subjected to systemic clinical examination and further clinical and laboratory investigations. Eight hundred and three (32.1%) individuals had urinary abnormalities at the first screening, which significantly decreased to 345 (13.8%) at the second screening, (P <0.001). Hematuria was the most common urinary abnormalities detected in 245 (9.8%) adolescents who had persistent urine abnormalities; 228 (9.1%) individuals had non glomerular hematuria. The hematuria was isolated in 150 (6%) individuals, combined with leukocyturia in 83 (3.3%) individuals, and combined with proteinuria in 12 (0.5%) individuals. Leukocyturia was detected in 150 (6%) of all studied adolescents; it was isolated in 39 (1.6%) individuals and combined with proteinuria in 28 (1.1%) of them. Asymptomatic bacteriuria was detected in 23 (0.9%) of all studied adolescents; all the cases were females. Proteinuria was detected in 65 (2.6%) of all the studied adolescents; 45 (1.8%) individuals had <0.5 g/day and twenty (0.8%) individuals had 0.5-3 g/day. Asymptomatic urinary abnormalities were more common in males than females and adolescents from rural than urban areas (P <0.01) and (P <0.001), respectively. The present study found a high prevalence of asymptomatic urinary abnormalities among adolescents in our population.

  14. Use of high-flow nasal cannula oxygenation in ICU adults: a narrative review.

    PubMed

    Papazian, Laurent; Corley, Amanda; Hess, Dean; Fraser, John F; Frat, Jean-Pierre; Guitton, Christophe; Jaber, Samir; Maggiore, Salvatore M; Nava, Stefano; Rello, Jordi; Ricard, Jean-Damien; Stephan, François; Trisolini, Rocco; Azoulay, Elie

    2016-09-01

    Oxygen therapy can be delivered using low-flow, intermediate-flow (air entrainment mask), or high-flow devices. Low/intermediate-flow oxygen devices have several drawbacks that cause critically ill patients discomfort and translate into suboptimal clinical results. These include limitation of the FiO2 (due to the high inspiratory flow often observed in patients with respiratory failure), and insufficient humidification and warming of the inspired gas. High-flow nasal cannula oxygenation (HFNCO) delivers oxygen flow rates of up to 60 L/min and over the last decade its effect on clinical outcomes has widely been evaluated, such as in the improvement of respiratory distress, the need for intubation, and mortality. Mechanisms of action of HFNCO are complex and not limited to the increased oxygen flow rate. The main aim of this review is to guide clinicians towards evidence-based clinical practice guidelines. It summarizes current knowledge about HFNCO use in ICU patients and the potential areas of uncertainties. For instance, it has been recently suggested that HFNCO could improve the outcome of patients with hypoxemic acute respiratory failure. In other settings, research is ongoing and additional evidence is needed. For instance, if intubation is required, studies suggest that HFNCO may help to improve preoxygenation and can be used after extubation. Likewise, HFNCO might be used in obese patients, or to prevent respiratory deterioration in hypoxemic patients requiring bronchoscopy, or for the delivery of aerosol therapy. However, areas for which conclusive data exist are limited and interventions using standardized HFNCO protocols, comparators, and relevant clinical outcomes are warranted. PMID:26969671

  15. Modeling highly transient flow, mass, and heat transport in the Chattahoochee River near Atlanta, Georgia

    USGS Publications Warehouse

    Jobson, Harvey E.; Keefer, Thomas N.

    1979-01-01

    A coupled flow-temperature model has been developed and verified for a 27.9-km reach of the Chattahoochee River between Buford Dam and Norcross, Ga. Flow in this reach of the Chattahoochee is continuous but highly regulated by Buford Dam, a flood-control and hydroelectric facility located near Buford, Ga. Calibration and verification utilized two sets of data collected under highly unsteady discharge conditions. Existing solution techniques, with certain minor improvements, were applied to verify the existing technology of flow and transport modeling. The linear, implicit finite-difference flow model was calibrated by use of a depth profile obtained at steady low flow and unsteady flow data obtained in March 1976. During the calibration period, the model was generally able to reproduce observed stages to within 0.15 m and discharges at less than 100 m 3 /s, to within 5 percent. Peak discharges of about 200 m 3 /s were under-estimated by about 20 percent. During the verification period, October 1975, the flow model reproduced observed stage changes to within about 0.15 m, and its timing and over-all performance was considered to be very good. Dye was added to the upstream end of the river reach at a constant rate while the river flow was highly unsteady. The numerical solution of either the conservative or nonconservative form of the mass-transport equation did an excellent job of simulating the observed concentrations of dye in the river. The temperature model was capable of predicting temperature changes through this reach of as large as 5.8?C with a RMS (root-mean-square) error of 0.32?C in October 1975 and 0.20?C in March 1976. Hydropulsation has a significant effect on the water temperature below Buford Dam. These effects are very complicated because they are quite dependent on the timing of the release with respect to both the time of day and past releases.

  16. Controlling secondary flows in very highly-loaded low-pressure turbine cascades

    NASA Astrophysics Data System (ADS)

    Knezevici, Daniel C.

    This thesis documents experimental and computational results of a research program investigating the aerodynamic losses generated by extremely highly loaded low-pressure turbine blades, with particular focus on the three-dimensional flow near the endwall. The study identifies the physical mechanisms associated with loss generation and documents changes in the flow field that result from the application of passive flow control techniques. The experimental study was conducted in Carleton University's low-speed, linear cascade wind tunnel. Quantitative results include seven-hole pneumatic probe pressure measurements downstream of the cascade to assess blade row losses, as well as detailed measurements within the blade passage to track the development of flow structures. Qualitative results in the form of oil surface flow visualization on the endwall and blade suction surface are used to assist in the interpretation of the physics. The complementary computational studies were performed using Reynolds-averaged Navier-Stokes (RANS) simulations, providing detailed resolution of the various vortical structures comprising the endwall flow. The work examined two passive flow control techniques for mitigating endwall loss. The techniques were applied to very high-lift, low-pressure turbine airfoils with the goal of expanding the design space. The airfoils and both flow control techniques were designed by Pratt & Whitney Aircraft (PWA) using proprietary tools. It was found that endwall loss could be significantly reduced and the mechanisms of loss reduction were identified. The loss measurements have allowed plausible limits to be defined for a high-lift replacement of the baseline airfoil used in the study.

  17. Transient analysis of counterflowing jet over highly blunt cone in hypersonic flow

    NASA Astrophysics Data System (ADS)

    Barzegar Gerdroodbary, M.; Bishehsari, Shervin; Hosseinalipour, S. M.; Sedighi, K.

    2012-04-01

    Understanding the characteristics of various Counterflowing jets exiting from a nose cone is crucial for determining heat load reduction and usage of this device in various conditions. Such jets can undergo several flow regimes during venting, from initial supersonic flow, to transonic, to subsonic flow regimes as the pressure of jet decreases. A bow shock wave is a characteristic flow structure during the initial stage of the jet development, and this paper focuses on the development of the bow shock wave and the jet structure behind it. The transient behavior of a sonic counterflow jet is investigated using unsteady, axisymmetric Navier-Stokes solved with SST turbulence model at free stream Mach number of 5.75. The coolant gas (Carbon Dioxide and Helium) is chosen to inject into the hypersonic air flow at the nose of the model. The gases are considered to be ideal, and the computational domain is axisymmetric. The jet structure, including the shock wave and flow separation due to an adverse pressure gradient at the nose is investigated with a focus on the differences between high diffusivity coolant jet (Helium) and low diffusivity coolant jet (CO2) flow scenarios.

  18. A High-Resolution Godunov Method for Compressible Multi-Material Flow on Overlapping Grids

    SciTech Connect

    Banks, J W; Schwendeman, D W; Kapila, A K; Henshaw, W D

    2006-02-13

    A numerical method is described for inviscid, compressible, multi-material flow in two space dimensions. The flow is governed by the multi-material Euler equations with a general mixture equation of state. Composite overlapping grids are used to handle complex flow geometry and block-structured adaptive mesh refinement (AMR) is used to locally increase grid resolution near shocks and material interfaces. The discretization of the governing equations is based on a high-resolution Godunov method, but includes an energy correction designed to suppress numerical errors that develop near a material interface for standard, conservative shock-capturing schemes. The energy correction is constructed based on a uniform pressure-velocity flow and is significant only near the captured interface. A variety of two-material flows are presented to verify the accuracy of the numerical approach and to illustrate its use. These flows assume an equation of state for the mixture based on Jones-Wilkins-Lee (JWL) forms for the components. This equation of state includes a mixture of ideal gases as a special case. Flow problems considered include unsteady one-dimensional shock-interface collision, steady interaction of an planar interface and an oblique shock, planar shock interaction with a collection of gas-filled cylindrical inhomogeneities, and the impulsive motion of the two-component mixture in a rigid cylindrical vessel.

  19. High-resolution AUV mapping and lava flow ages at Axial Seamount

    NASA Astrophysics Data System (ADS)

    Clague, D. A.; Paduan, J. B.; Dreyer, B. M.; Caress, D. W.; Martin, J.

    2011-12-01

    Mapping along mid-ocean ridges, as on land, requires identification of flow boundaries and sequence, and ages of some flows to understand eruption history. Multibeam sonars on autonomous underwater vehicles (AUV) now generate 1-m resolution maps that resolve lava pillars, internal flow structures and boundaries, and lava flow emplacement sequences using crosscutting relations and abundance of fissures. MBARI has now mapped the summit caldera floor and rims and the upper south rift zone on Axial Seamount on the Juan de Fuca Ridge. With the advent of the high-resolution bathymetry and the ability to observe flow contacts to determine superposition using ROVs and submersibles, the missing component has been determining absolute ages of the flows. We used the MBARI ROV Doc Ricketts to collect short push cores (<30 cm) of the thin sediment nestled between pillow lava lobes and sieve and then hand-pick planktic foraminifera from the base of the cores to date by AMS 14C. Ages of planktic foraminifera are marine-calibrated in years before present, and provide minimum ages for the underlying flows, as there is probably some basal sediment that is not recovered. 14C ages have been determined for 10 cores near the summit of Axial Seamount and for 6 from the lowermost south rift. Ages of nearby samples commonly yield statistically identical ages, and 2 cores near the center of the caldera had multiple layers dated. These ages systematically increase with depth, indicating that redistribution of sediment by bottom currents does not significantly affect the stratigraphy. We will expand these collections in summer 2011. The coring is accompanied by collection of flow samples for chemistry and video observations to confirm contact locations and flow superposition inferred from the mapping data. Six ages from the lowermost part of the south rift of Axial Seamount include samples on a cone with deep summit crater that is ~16,580 aBP and on 5 flows between 950 and 1510 aBP. Two

  20. An arrayable flow-through microcentrifuge for high-throughput instrumentation

    PubMed Central

    Marziali, Andre; Willis, Thomas D.; Davis, Ronald W.

    1999-01-01

    A compact, flow-through centrifugation system has been developed specifically for high-throughput centrifugation of large numbers of samples. The instrument is based on multiple high-speed rotors that also serve as sample holders. The small size of the rotors allows them to be arrayed in a standard 96-well microtiter plate spacing, making this device ideal for highly parallel automated instrumentation. Though initially designed for cell separation in DNA sequencing protocols, the flow-through centrifuge can be used to replace conventional centrifugation in most processes involving small samples. Techniques for recovery of both the supernatant and the pellet have been developed, as well as techniques for sample mixing, and cleaning of the reusable rotors. This paper discusses the design and performance of the flow-through centrifuge applied to cell separation and resuspension and to DNA purification and concentration. PMID:9874772