Evaluation of the single-pass flow-through test to support a low-activity waste specification
International Nuclear Information System (INIS)
McGrail, B.P.; Peeler, D.K.
1995-09-01
A series of single-pass flow-through (SPFT) tests was performed on five reference low-activity waste glasses and a reference glass from the National Institute of Standards and Technology to support a product specification for low-activity waste (LAW) forms. The results showed that the SPFT test provides a means to quantitatively distinguish among LAW glass forms in terms of their forward reaction rate at a given temperature and solution pH. Two of the test glasses were also subjected to SPFT testing at Argonne National Laboratory (ANL). Forward reaction rate constants calculated from the ANL test data were 100 to over 1,000 times larger than the values obtained from the SPFT tests conducted at PNL. An analysis of the ANL results showed that they were inconsistent with independent measurements done on glasses of similar composition, the known pH-dependence of the forward rate, and with the results from low surface-area-to-volume, short duration product consistency tests. Because the data set obtained from the SPFT tests done at PNL was consistent with each of these same factors, a detailed examination of the test procedures used at both laboratories was performed to determine the cause(s) of the discrepancy. The omission of background subtraction in the data analysis procedure and the short-duration (on the order of hours) of the ANL tests are factors that may have significantly affected the calculated rates
American Society for Testing and Materials. Philadelphia
2010-01-01
1.1 This practice describes a single-pass flow-through (SPFT) test method that can be used to measure the dissolution rate of a homogeneous silicate glass, including nuclear waste glasses, in various test solutions at temperatures less than 100°C. Tests may be conducted under conditions in which the effects from dissolved species on the dissolution rate are minimized to measure the forward dissolution rate at specific values of temperature and pH, or to measure the dependence of the dissolution rate on the concentrations of various solute species. 1.2 Tests are conducted by pumping solutions in either a continuous or pulsed flow mode through a reaction cell that contains the test specimen. Tests must be conducted at several solution flow rates to evaluate the effect of the flow rate on the glass dissolution rate. 1.3 This practice excludes static test methods in which flow is simulated by manually removing solution from the reaction cell and replacing it with fresh solution. 1.4 Tests may be conducted wit...
International Nuclear Information System (INIS)
BP McGrail; HT Schaef; JP Icenhower; PF Martin; RD Orr; VL Legore
1999-01-01
This report summarizes our findings from pressurized unsaturated flow (PUF) and single-pass flow-through (SPFT) experiments to date. Results from the PUF test of a Pu-bearing ceramic with enclosing surrogate high-level waste glass show that the glass reacts rapidly to alteration products. Glass reaction causes variations in the solution pH in contact with the ceramic materials. We also document variable concentrations of Pu in solution, primarily in colloidal form, which appear to be related to secular variations in solution composition. The apparent dissolution rate of the ceramic waste form, based on Ba concentrations in the effluent, is estimated at le 10 -5 g/(m 2 · d). Pu-bearing colloids were recovered in the size range of 0.2 to 2 microm, but it is not clear that such entities would be transported in a system that is not advective-flow dominated. Results from SPFT experiments give information on the corrosion resistance of two surrogate Pu-ceramics (Ce-pyrochlore and Ce-zirconolite) at 90 C over a pH range of 2 to 12. The two ceramics were doped with minor quantities (approximately0.1 mass%) of MoO 3 , so that concentrations of Mo in the effluent solution could be used to monitor the reaction behavior of the materials. The data obtained thus far from experiments with durations up to 150 d do not conclusively prove that the solid-aqueous solution systems have reached steady-state conditions. Therefore, the dissolution mechanism cannot be determined. Apparent dissolution rates of the two ceramic materials based on Ce, Gd, and Mo concentrations in the effluent solutions from the SPFT are nearly identical and vary between 1.1 to 8.5 x 10 -4 g/(m 2 · d). In addition, the data reveal a slightly amphoteric dissolution behavior, with a minimum apparent rate at pH = 7 to 8, over the pH range examined. Results from two related ceramic samples suggest that radiation damage can have a measurable effect on the dissolution of titanium-based ceramics. The rare earth
Wang, Guohui; Um, Wooyong; Wang, Zheming; Reinoso-Maset, Estela; Washton, Nancy M; Mueller, Karl T; Perdrial, Nicolas; O'Day, Peggy A; Chorover, Jon
2017-10-03
The reaction of acidic radioactive waste with sediments can induce mineral transformation reactions that, in turn, control contaminant fate. Here, sediment weathering by synthetic uranium-containing acid solutions was investigated using bench-scale experiments to simulate waste disposal conditions at Hanford's cribs (Hanford, WA). During acid weathering, the presence of phosphate exerted a strong influence over uranium mineralogy and a rapidly precipitated, crystalline uranium phosphate phase (meta-ankoleite [K(UO 2 )(PO 4 )·3H 2 O]) was identified using spectroscopic and diffraction-based techniques. In phosphate-free system, uranium oxyhydroxide minerals such as K-compreignacite [K 2 (UO 2 ) 6 O 4 (OH) 6 ·7H 2 O] were formed. Single-pass flow-through (SPFT) and column leaching experiments using synthetic Hanford pore water showed that uranium precipitated as meta-ankoleite during acid weathering was strongly retained in the sediments, with an average release rate of 2.67 × 10 -12 mol g -1 s -1 . In the absence of phosphate, uranium release was controlled by dissolution of uranium oxyhydroxide (compreignacite-type) mineral with a release rate of 1.05-2.42 × 10 -10 mol g -1 s -1 . The uranium mineralogy and release rates determined for both systems in this study support the development of accurate U-release models for the prediction of contaminant transport. These results suggest that phosphate minerals may be a good candidate for uranium remediation approaches at contaminated sites.
Energy Technology Data Exchange (ETDEWEB)
Wang, Guohui [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Um, Wooyong [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Pohang University of Science and Technology (POSTECH), Pohang, South Korea; Wang, Zheming [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Reinoso-Maset, Estela [Sierra; Washton, Nancy M. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Mueller, Karl T. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Perdrial, Nicolas [Department; Department; O’Day, Peggy A. [Sierra; Chorover, Jon [Department
2017-09-21
The reaction of acidic radioactive waste with sediments can induce mineral transformation reactions that, in turn, control contaminant fate. Here, sediment weathering by synthetic uranium-containing acid solutions was investigated using bench-scale experiments to simulate waste disposal conditions at Hanford’s cribs, USA. During acid weathering, the presence of phosphate exerted a strong influence over uranium mineralogy and a rapidly precipitated, crystalline uranium phosphate phase (meta-ankoleite [K(UO2)(PO4)·3H2O]) was identified using spectroscopic and diffraction-based techniques. In phosphate-free system, uranium oxyhydroxide minerals such as K-compreignacite [K2(UO2)6O4(OH)6·7H2O] were formed. Single-pass flow-through (SPFT) and column leaching experiments using synthetic Hanford pore water showed that uranium precipitated as meta-ankoleite during acid weathering was strongly retained in the sediments, with an average release rate of 2.67E-12 mol g-1 s-1. In the absence of phosphate, uranium release was controlled by dissolution of uranium oxyhydroxide (compreignacite-type) mineral with a release rate of 1.05-2.42E-10 mol g-1 s-1. The uranium mineralogy and release rates determined for both systems in this study support the development of accurate U-release models for prediction of contaminant transport. These results suggest that phosphate minerals may be a good candidate for uranium remediation approaches at contaminated sites.
FY2016 ILAW Glass Corrosion Testing with the Single-Pass Flow-Through Method
Energy Technology Data Exchange (ETDEWEB)
Neeway, James J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Asmussen, Robert M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Parruzot, Benjamin PG [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cordova, Elsa [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Leavy, Ian I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephenson, John R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McElroy, Erin M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2017-04-21
The inventory of immobilized low-activity waste (ILAW) produced at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will be disposed of at the near-surface, on-site Integrated Disposal Facility (IDF). When groundwater comes into contact with the waste form, the glass will corrode and radionuclides will be released into the near-field environment. Because the release of the radionuclides is dependent on the dissolution rate of the glass, it is important that the performance assessment (PA) model accounts for the dissolution rate of the glass as a function of various chemical conditions. To accomplish this, an IDF PA model based on Transition State Theory (TST) can be employed. The model is able to account for changes in temperature, exposed surface area, and pH of the contacting solution as well as the effect of silicon concentrations in solution, specifically the activity of orthosilicic acid (H4SiO4), whose concentration is directly linked to the glass dissolution rate. In addition, the IDF PA model accounts for the alkali-ion exchange process as sodium is leached from the glass and into solution. The effect of temperature, pH, H4SiO4 activity, and the rate of ion-exchange can be parameterized and implemented directly into the PA rate law model. The rate law parameters are derived from laboratory tests with the single-pass flow-through (SPFT) method. To date, rate law parameters have been determined for seven ILAW glass compositions, thus additional rate law parameters on a wider range of compositions will supplement the existing body of data for PA maintenance activities. The data provided in this report can be used by ILAW glass scientists to further the understanding of ILAW glass behavior, by IDF PA modelers to use the rate law parameters in PA modeling efforts, and by Department of Energy (DOE) contractors and decision makers as they assess the IDF PA program.
Accidents and transients analyses of a super fast reactor with single flow pass core
International Nuclear Information System (INIS)
Sutanto,; Oka, Yoshiaki
2014-01-01
Highlights: • Safety analysis of a Super FR with single flow pass core is conducted. • Loss of feed water flow leads to a direct effect on the loss of fuel channel flow. • The core pressure is sensitive to LOCA accidents due to the direct effect. • Small LOCA introduces a critical break. • The safety criteria for all selected events are satisfied. - Abstract: The supercritical water cooled fast reactor with single flow pass core has been designed to simplify refueling and the structures of upper and lower mixing plenums. To evaluate the safety performance, safety analysis has been conducted with regard to LOCA and non-LOCA accidents including transient events. Safety analysis results show that the safety criteria are satisfied for all selected events. The total loss of feed water flow is the most important accident which the maximum cladding surface temperature (MCST) is high due to a direct effect of the accident on the total loss of flow in all fuel assemblies. However, actuation of the ADS can mitigate the accident. Small LOCA also introduces a critical break at 7.8% break which results high MCST at BOC because the scram and ADS are not actuated. Early ADS actuation is effective to mitigate the accident. In large LOCA, 100% break LOCA results a high MCST of flooding phase at BOC due to high power peaking at the bottom part. Use of high injection flow rate by 2 LPCI units is effective to decrease the MCST
ILAW Glass Testing for Disposal at IDF: Phase 1 Testing
Energy Technology Data Exchange (ETDEWEB)
Papathanassiu, Adonia [The Catholic Univ. of America, Washington, DC (United States). Virteous State Lab.; Muller, Isabelle S. [The Catholic Univ. of America, Washington, DC (United States). Virteous State Lab.; Brandys, Marek [The Catholic Univ. of America, Washington, DC (United States). Virteous State Lab.; Gilbo, Konstantin [The Catholic Univ. of America, Washington, DC (United States). Virteous State Lab.; Barkatt, Aaron [The Catholic Univ. of America, Washington, DC (United States). Virteous State Lab.; Joseph, Innocent [EnergySolutions Federal EPC, Inc., Columbia, MD (United States); The Catholic Univ. of America, Washington, DC (United States). Virteous State Lab.; Pegg, Ian L. [The Catholic Univ. of America, Washington, DC (United States). Virteous State Lab.; Brown, Elvie E. [Washington River Protection Solutions, LLC, Richland, WA (United States); Swanberg, David J. [Washington River Protection Solutions, LLC, Richland, WA (United States)
2011-04-11
This document reports the results of the testing of phase 1 ORP LAW (low activity waste) glasses, also identified as enhanced LAW glasses. Testing involved are SPFT (Single Pass Flow Through), VHT (Vapor Hydration Test), and PCT (Product Consistency Test), along with the analytical tests (XRD and SEM-EDS). This report contains the data of the high waste loading ORP LAW glasses that will be used for the performance assessment of the IDF (Integrated Disposal Facility).
ILAW Glass Testing for Disposal at IDF: Phase 1 Testing
International Nuclear Information System (INIS)
Papathanassiu, Adonia; Swanberg, David J.
2011-01-01
This document reports the results of the testing of phase 1 ORP LAW (low activity waste) glasses, also identified as enhanced LAW glasses. Testing involved are SPFT (Single Pass Flow Through), VHT (Vapor Hydration Test), and PCT (Product Consistency Test), along with the analytical tests (XRD and SEM-EDS). This report contains the data of the high waste loading ORP LAW glasses that will be used for the performance assessment of the IDF (Integrated Disposal Facility).
International Nuclear Information System (INIS)
Chang-Soon Koh; Byung Tae Kim; Myung Chul Lee; Bo Yeon Cho
1982-01-01
Pulmonary hypertension in mitral valvular cardiac disease has been evaluated in 122 patients by a modified upper lung/lower count ratio using single-pass radionuclide angiocardiography. The mean upper lung/lower lung radio correlates well with pulmonary artery mean (r=0.483) and wedge pressure (r=0.804). After correction surgery of the cardiac valve, the ratio decreases and returns to normal range in patients judged clinically to have good surgical benifit. This modified method using single-pass technique provides additional simple, reproducible and nontraumatic results of regional pulmonary blood flow and appears to be correlated with the degree of pulmonary hypertension in mitral heart disease
Single and double pass solar air heaters with wire mesh as packing bed
Energy Technology Data Exchange (ETDEWEB)
Aldabbagh, L.B.Y.; Egelioglu, F. [Mechanical Engineering Department, Eastern Mediterranean University, Magosa, Mersin 10 (Turkey); Ilkan, M. [School of Computing and Tecnology, Eastern Mediterranean University, Magosa, Mersin 10 (Turkey)
2010-09-15
The thermal performances of single and double pass solar air heaters with steel wire mesh layers are used instead of a flat absorber plate are investigated experimentally. The effects of mass flow rate of air on the outlet temperature and thermal efficiency were studied. The results indicate that the efficiency increases with increasing the mass flow rate for the range of the flow rate used in this work between 0.012 and 0.038 kg/s. For the same flow rate, the efficiency of the double pass is found to be higher than the single pass by 34-45%. Moreover, the maximum efficiencies obtained for the single and the double pass air collectors are 45.93 and 83.65% respectively for the mass flow rate of 0.038 kg/s. Comparison of the results of a packed bed collector with those of a conventional collector shows a substantial enhancement in the thermal efficiency. (author)
Single beam pass migmacell method and apparatus
International Nuclear Information System (INIS)
Maglich, B.C.; Nering, J.E.; Mazarakis, M.G.; Miller, R.A.
1976-01-01
The invention provides improvements in migmacell apparatus and method by dispensing with the need for metastable confinement of injected molecular ions for multiple precession periods. Injected molecular ions undergo a 'single pass' through the reaction volume. By preconditioning the injected beam such that it contains a population distribution of molecules in higher vibrational states than in the case of a normal distribution, injected molecules in the single pass exper-ience collisionless dissociation in the migmacell under magnetic influence, i.e., so-called Lorentz dissociation. Dissociationions then form atomic migma
Studies on water turbine runner which fish can pass through: In case of single stage axial runner
International Nuclear Information System (INIS)
Shimizu, Yukimari; Maeda, Takao; Nagoshi, Osamu; Ieda, Kazuma; Shinma, Hisako; Hagimoto, Michiko
1994-01-01
The relationship between water turbine runner design and operation and the safe passage of fish through the turbine is studied. The kinds of fish used in the tests are a dace, a sweet fish and a small salmon. A single stage axial runner is used. The velocity and pressure distributions were measured inside the turbine casing and along the casing wall. Many pictures showing fish passing through the rotating runner were taken and analyzed. The swimming speed of the fish was examined from video recordings. Fish pass through the runner more rapidly when they can determine and choose the easier path. Injury and mortality of fish are affected by the runner speed and the location of impact of the runner on the fish body
Flow characteristics through a single fracture of artificial fracture system
International Nuclear Information System (INIS)
Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Jeon, Seok Won
2001-04-01
Fracture flow in rock masses is one of the most important issues in petroleum engineering, geology, and hydrogeology. Especially, in case of the HLW disposal, groundwater flow in fractures is an important factor in the performance assessment of the repository because the radionuclides move along the flowing groundwater through fractures. Recently, the characterization of fractures and the modeling of fluid flow in fractures are studied by a great number of researchers. Among those studies, the hydraulic behavior in a single fracture is one of the basic issues for understanding of fracture flow in rockmass. In this study, a fluid flow test in the single fracture made of transparent epoxy replica was carried out to obtain the practical exponent values proposed from the Cubic law and to estimate the flow rates through a single fracture. Not only the relationship between flow rates and the geometry of fracture was studied, but also the various statistical parameters of fracture geometry were compared to the effective transmissivity data obtained from computer simulation.
Flow and clogging of a sheep herd passing through a bottleneck.
Garcimartín, A; Pastor, J M; Ferrer, L M; Ramos, J J; Martín-Gómez, C; Zuriguel, I
2015-02-01
We present an experimental study of a flock passing through a narrow door. Video monitoring of daily routines in a farm has enabled us to collect a sizable amount of data. By measuring the time lapse between the passage of consecutive animals, some features of the flow regime can be assessed. A quantitative definition of clogging is demonstrated based on the passage time statistics. These display broad tails, which can be fitted by power laws with a relatively large exponent. On the other hand, the distribution of burst sizes robustly evidences exponential behavior. Finally, borrowing concepts from granular physics and statistical mechanics, we evaluate the effect of increasing the door size and the performance of an obstacle placed in front of it. The success of these techniques opens new possibilities regarding their eventual extension to the management of human crowds.
INVESTIGATION OF SINGLE-PASS/DOUBLE-PASS TECHNIQUES ON FRICTION STIR WELDING OF ALUMINIUM
Directory of Open Access Journals (Sweden)
N.A.A. Sathari
2014-12-01
Full Text Available The aim of this research is to study the effects of single-pass/ double-pass techniques on friction stir welding of aluminium. Two pieces of AA1100 with a thickness of 6.0 mm were friction stir welded using a CNC milling machine at rotational speeds of 1400 rpm, 1600 rpm and 1800 rpm respectively for single-pass and double-pass. Microstructure observations of the welded area were studied using an optical microscope. The specimens were tested by using a tensile test and Vickers hardness test to evaluate their mechanical properties. The results indicated that, at low rotational speed, defects such as ‘surface lack of fill’ and tunnels in the welded area contributed to a decrease in mechanical properties. Welded specimens using double-pass techniques show increasing values of tensile strength and hardness. From this investigation it is found that the best parameters of FSW welded aluminium AA1100 plate were those using double-pass techniques that produce mechanically sound joints with a hardness of 56.38 HV and 108 MPa strength at 1800 rpm compared to the single-pass technique. Friction stir welding, single-pass/ double-pass techniques, AA1100, microstructure, mechanical properties.
Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results
International Nuclear Information System (INIS)
Coles, D.G.
1981-01-01
A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for 237 Np and 239 Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected the leach rate, but only slightly. Temperature effects were significant. Plutonium leach rate was lower at higher temperature suggesting that Pu sorption onto the beads was enhanced at the higher temperature. The range of leach rates for all analyzed elements (except Pu), at both temperatures, at all three flow rates, and with all three leachant compositions varied over only three orders of magnitude. The range of variables used in this experiment covered those expected in many proposed repository environments. The preliminary interpretation of the results aPPh 3 also reacted with Mn 2 (CO) 10 and Cp 2 Mo 2 (CO) 6 to give a variety of products at room temperature. A radical mechanism was suggested
High peak-power kilohertz laser system employing single-stage multi-pass amplification
Shan, Bing; Wang, Chun; Chang, Zenghu
2006-05-23
The present invention describes a technique for achieving high peak power output in a laser employing single-stage, multi-pass amplification. High gain is achieved by employing a very small "seed" beam diameter in gain medium, and maintaining the small beam diameter for multiple high-gain pre-amplification passes through a pumped gain medium, then leading the beam out of the amplifier cavity, changing the beam diameter and sending it back to the amplifier cavity for additional, high-power amplification passes through the gain medium. In these power amplification passes, the beam diameter in gain medium is increased and carefully matched to the pump laser's beam diameter for high efficiency extraction of energy from the pumped gain medium. A method of "grooming" the beam by means of a far-field spatial filter in the process of changing the beam size within the single-stage amplifier is also described.
Fuel-element failures in Hanford single-pass reactors 1944--1971
Energy Technology Data Exchange (ETDEWEB)
Gydesen, S.P.
1993-07-01
The primary objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of emissions since 1944 from the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. To estimate the doses, the staff of the Source Terms Task use operating information from historical documents to approximate the radioactive emissions. One source of radioactive emissions to the Columbia River came from leaks in the aluminum cladding of the uranium metal fuel elements in single-pass reactors. The purpose of this letter report is to provide photocopies of the documents that recorded these failures. The data from these documents will be used by the Source Terms Task to determine the contribution of single-pass reactor fuel-element failures to the radioactivity of the reactor effluent from 1944 through 1971. Each referenced fuel-element failure occurring in the Hanford single-pass reactors is addressed. The first recorded failure was in 1948, the last in 1970. No records of fuel-element failures were found in documents prior to 1948. Data on the approximately 2000 failures which occurred during the 28 years (1944--1971) of Hanford single-pass reactor operations are provided in this report.
An experimental evaluation of multi-pass solar air heaters
Energy Technology Data Exchange (ETDEWEB)
Satcunanathan, S.; Persad, P.
1980-12-01
Three collectors of identical dimensions but operating in the single-pass, two-pass and three-pass modes were tested simultaneously under ambient conditions. It was found that the two-pass air heater was consistently better than the single-pass air heater over the day for the range of mass flow rates considered. It was also found that at a mass flow rate of 0.0095 kg s/sup -1/ m/sup -2/, the thermal performances of the two-pass and three-pass collectors were identical, but at higher flow rates the two-pass collector was superior to the three-pass collector, the superiority decreasing with increasing mass flow rate.
DEFF Research Database (Denmark)
Jensen, Ole Bjarlin; Petersen, Paul Michael
2013-01-01
A generic approach for generation of tunable single frequency light is presented. 340 mW of near diffraction limited, single-frequency, and tunable blue light around 459 nm is generated by sum-frequency generation (SFG) between two tunable tapered diode lasers. One diode laser is operated in a ring...... cavity and another tapered diode laser is single-passed through a nonlinear crystal which is contained in the coupled ring cavity. Using this method, the single-pass conversion efficiency is more than 25%. In contrast to SFG in an external cavity, the system is entirely self-stabilized with no electronic...
Kist, David; Burns, A Jay; Sanner, Roth; Counters, Jeff; Zelickson, Brian
2006-02-01
The radio-frequency (RF) device is a system capable of volumetric heating of the mid to deep dermis and selective heating of the fibrous septa strands and fascia layer. Clinically, these effects promote dermal collagen production, and tightening of these deep subcutaneous structures. A new technique of using multiple low energy passes has been described which results in lower patient discomfort and fewer side effects. This technique has also been anecdotally described as giving more reproducible and reliable clinical results of tissue tightening and contouring. This study will compare ultrastructural changes in collagen between a single pass high energy versus up to five passes of a multiple pass lower energy treatment. Three subjects were consented and treated in the preauricular region with the RF device using single or multiple passes (three or five) in the same 1.5 cm(2) treatment area with a slight delay between passes to allow tissue cooling. Biopsies from each treatment region and a control biopsy were taken immediately, 24 hours or 6 months post treatment for electron microscopic examination of the 0-1 mm and 1-2 mm levels. Sections of tissue 1 mm x 1 mm x 80 nm were examined with an RCA EMU-4 Transmission Electron Microscope. Twenty sections from 6 blocks from each 1 mm depth were examined by 2 blinded observers. The morphology and degree of collagen change in relation to area examined was compared to the control tissue, and estimated using a quantitative scale. Ultrastructural examination of tissue showed that an increased amount of collagen fibril changes with increasing passes at energies of 97 J (three passes) and 122 J (five passes), respectively. The changes seen after five multiple passes were similar to those detected after much more painful single pass high-energy treatments. This ultrastructural study shows changes in collagen fibril morphology with an increased effect demonstrated at greater depths of the skin with multiple low-fluence passes
Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results
International Nuclear Information System (INIS)
Coles, D.G.
1981-01-01
A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for 237 Np and 239 Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected the leach rate, but only slightly. Temperature effects were significant. Plutonium leach rate was lower at higher temperature suggesting that Pu sorption onto the beads was enhanced at the higher temperature. The range of leach rates for all analyzed elements (except Pu), at both temperature, at all three flow rates, and with all three leachant compositions varied only three orders of magnitude. The range of variables used in this experiment covered those expected in many proposed repository environments. The preliminary interpretation of the results also indicated that matrix dissolution may be the dominant leaching mechanism, at least for Np in bicarbonate leachant. Regardless of the leaching mechanism the importance of this study is that it bounds the effects of repository environments when the ground water is oxidizing and when it doesn't reach the waste form until the waste has cooled to ambient rock temperature
Survival Rates of Juvenile Salmonids Passing Through the Bonneville Dam and Spillway in 2008
Energy Technology Data Exchange (ETDEWEB)
Ploskey, Gene R.; Weiland, Mark A.; Faber, Derrek M.; Deng, Zhiqun; Johnson, Gary E.; Hughes, James S.; Zimmerman, Shon A.; Monter, Tyrell J.; Cushing, Aaron W.; Wilberding, Matthew C.; Durham, Robin E.; Townsend, R. L.; Skalski, J. R.; Buchanan, Rebecca A.; Kim, Jina; Fischer, Eric S.; Meyer, Matthew M.; McComas, Roy L.; Everett, Jason
2009-12-28
This report describes a 2008 acoustic telemetry survival study conducted by the Pacific Northwest National Laboratory for the Portland District of the U.S. Army Corps of Engineers. The study estimated the survival of juvenile Chinook salmon and steelhead passing Bonneville Dam (BON) and its spillway. Of particular interest was the relative survival of smolts detected passing through end spill bays 1-3 and 16-18, which had deep flow deflectors immediately downstream of spill gates, versus survival of smolts passing middle spill bays 4-15, which had shallow flow deflectors.
Directory of Open Access Journals (Sweden)
Daniel W. Visscher
1998-01-01
Full Text Available Two-color, multiparametric synthesis phase fraction (SPF analysis of cytokeratin-labeled epithelial cells was flow cytometrically performed on both benign (SPFb and malignant tissue samples (if available, SPFt from 132 mastectomy/lumpectomy specimens. These data were then correlated with clinicopathologic features, including (1 tumor differentiation, (2 the proportion of tumor comprised of duct carcinoma-in situ (DCIS, and (3 the histology of accompanying benign breast tissue, classified by predominant microscopic pattern as intact, normal terminal duct lobular units (NTDLU, 34% of cases, atrophic (AT, 33% of cases, proliferative fibrocystic (PFC, 26% of cases, and non-proliferative fibrocystic (NPFC, 7% of cases. SPFt was inversely correlated with extent of DCIS (DCIS =0 – 20% tumor volume – 12.7% mean SPFt, vs. DCIS >20% tumor volume – 6.4% mean SPFt, p = 0.001. SPFt also correlated with the histology of background benign breast tissue (NTDLU – 14.8% mean SPFt vs. AT – 6.9% mean SPFt vs. PFC – 12.7% mean SPFt, p = 0.05 but it did not correlate with patient age or SPFb (overall mean =0.73%. SPFb was correlated with patient age (>56 yr – 0.59% mean SPFb vs. < yr – 0.84% mean SPFb, p = 0.02, with background histology (NTDLU – 1.1% mean SPFb vs. AT – 0.43% mean SPFb vs. PFC – 0.70% mean SPFb, p < 0.02 and with the grade of the neoplasm (well/moderate – 0.58% mean vs. poorly differentiated – 0.85% mean, p = 0.04. Patients having a background of PFC were significantly older than patients with a background of NTDLU (45.2 yr vs. 60.2 yr, p = 0.01.
Oil price pass-through into inflation
International Nuclear Information System (INIS)
Chen, Shiu-Sheng
2009-01-01
This paper uses data from 19 industrialized countries to investigate oil price pass-through into inflation across countries and over time. A time-varying pass-through coefficient is estimated and the determinants of the recent declining effects of oil shocks on inflation are investigated. The appreciation of the domestic currency, a more active monetary policy in response to inflation, and a higher degree of trade openness are found to explain the decline in oil price pass-through. (author)
In-situ characterization of symmetric dual-pass architecture of microfluidic co-laminar flow cells
International Nuclear Information System (INIS)
Ibrahim, Omar A.; Goulet, Marc-Antoni; Kjeang, Erik
2016-01-01
Highlights: • An analytical cell design is proposed for characterization of dual-pass flow cells • High power density up to 0.75 W cm −2 is demonstrated • The performance contributions of the inlet and outlet passes are of the same order • Downstream crossover is analyzed as a function of cell current and flow rate - Abstract: Microfluidic co-laminar flow cells with dual-pass architecture enable fuel recirculation and in-situ regeneration, and offer improvements in performance characteristics. In this work, a unique analytical cell design is proposed, with two split portions having flow-through porous electrodes. Each cell portion is first tested individually with vanadium redox species and the results are used to quantify the previously unknown crossover losses at the downstream portion of the cell, shown here to be a strong function of the flow rate. Moreover, the upstream cell portion demonstrates impressive room-temperature power density up to 0.75 W cm −2 at 1.0 A cm −2 , which is the highest performance reported to date for a microfluidic vanadium redox battery. Next, the two cell portions are connected in parallel to resemble a complete cell with dual-pass architecture, thereby enabling novel in-situ diagnostics of the inlet and outlet passes of the cell. For instance, the reactant utilization efficiency of the downstream cell portion is shown to be on the same order as that of the upstream portion at both low and high flow rates. Furthermore, in-situ regeneration is also demonstrated. Overall, the present results provide a deeper understanding of dual-pass reactant conversion and crossover which will be useful for future device optimization.
Endogenous trade participation with incomplete exchange rate pass-through
Imura, Yuko
2013-01-01
This paper investigates the implications of endogenous trade participation for international business cycles, trade flow dynamics and exchange rate pass-through when price adjustments are staggered across firms. I develop a two-country dynamic stochastic general equilibrium model wherein firms make state-dependent decisions on entry and exit in the export market and the frequency of price adjustment is time-dependent. Consistent with recent empirical findings, producers of traded goods in thi...
Retail Bank Interest Rate Pass-Through; Is Chile Atypical?
Alessandro Rebucci; Marco A Espinosa-Vega
2003-01-01
This paper investigates empirically the pass-through of money market interest rates to retail banking interest rates in Chile, the United States, Canada, Australia, New Zealand, and five European countries. Overall, Chile's pass-through does not appear atypical. Based on a standard error-correction model, we find that, as in most countries considered, Chile's measured pass-through is incomplete. But Chile's pass-through is also faster than in many other countries considered and is comparable ...
International Nuclear Information System (INIS)
Pierce, Eric M.; McGrail, B PETER.; Icenhower, J P.; Rodriguez, Elsa A.; Steele, Jackie L.; Baum, Steven R.
2004-01-01
The reaction kinetics of glass is controlled by matrix dissolution and ion exchange (IEX). Dissolution of an alkali-rich simulated borosilicate waste glass was investigated using single-pass flow-through (SPFT) experiments. Experiments were conducted as a function of temperature, pH, and solution composition by varying the SiO 2 (aq) activity in the influent solution. Results showed that under dilute conditions matrix dissolution increased with increasing pH and temperature, and decreased with increasing SiO 2 (aq) activity. IEX rates decreased with increasing pH and temperature, and increased with increasing SiO 2 (aq) activity. Over the solution composition range interrogated in this study the dominant dissolution mechanism changed from matrix dissolution to IEX. These results suggest that ''secondary'' reactions may become dominant under certain environmental conditions and emphasize the need to incorporate these reactions into dissolution rate models
12 CFR 560.32 - Pass-through investments.
2010-01-01
... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Pass-through investments. 560.32 Section 560.32 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY LENDING AND INVESTMENT Lending and Investment Powers for Federal Savings Associations § 560.32 Pass-through investments. (a) A...
An experimental investigation of flow around a vehicle passing through a tornado
Suzuki, Masahiro; Obara, Kouhei; Okura, Nobuyuki
2016-03-01
Flow around a vehicle running through a tornado was investigated experimentally. A tornado simulator was developed to generate a tornado-like swirl flow. PIV study confirmed that the simulator generates two-celled vortices which are observed in the natural tornadoes. A moving test rig was developed to run a 1/40 scaled train-shaped model vehicle under the tornado simulator. The car contained pressure sensors, a data logger with an AD converter to measure unsteady surface pressures during its run through the swirling flow. Aerodynamic forces acting on the vehicle were estimated from the pressure data. The results show that the aerodynamic forces change its magnitude and direction depending on the position of the car in the swirling flow. The asymmetry of the forces about the vortex centre suggests the vehicle itself may deform the flow field.
An experimental investigation of flow around a vehicle passing through a tornado
Directory of Open Access Journals (Sweden)
Suzuki Masahiro
2016-01-01
Full Text Available Flow around a vehicle running through a tornado was investigated experimentally. A tornado simulator was developed to generate a tornado-like swirl flow. PIV study confirmed that the simulator generates two-celled vortices which are observed in the natural tornadoes. A moving test rig was developed to run a 1/40 scaled train-shaped model vehicle under the tornado simulator. The car contained pressure sensors, a data logger with an AD converter to measure unsteady surface pressures during its run through the swirling flow. Aerodynamic forces acting on the vehicle were estimated from the pressure data. The results show that the aerodynamic forces change its magnitude and direction depending on the position of the car in the swirling flow. The asymmetry of the forces about the vortex centre suggests the vehicle itself may deform the flow field.
Pass-Through to Import Prices: Evidence from Developing Countries
Miguel Fuentes
2007-01-01
In this paper I study the pass-through of nominal exchange rate changes to the price of imported goods in four developing countries. The results indicate that 75% of changes in the exchange rate are passed-through to the domestic currency price of imported goods within one quarter. Complete pass-through is attained within one year. There is no evidence that exchange rate pass-through to the price of imported goods has declined over time even in those countries that have managed to reduce infl...
International Nuclear Information System (INIS)
Baek, Seung Man; Kim, Charn Jung; Jeon, Dong Hyup; Nam, Jin Hyun
2012-01-01
This study numerically investigates pressure drop and flow distribution characteristics of serpentine flow fields (SFFs) that are designed for polymer electrolyte membrane fuel cells, which consider the Poiseuille flow with secondary pressure drop in the gas channel (GC) and the Darcy flow in the porous gas diffusion layer (GDL). The numerical results for a conventional SFF agreed well with those obtained via computational fluid dynamics simulations, thus proving the validity of the present flow network model. This model is employed to characterize various single and parallel SFFs, including multi-pass serpentine flow fields (MPSFFs). Findings reveal that under rib convection (convective flow through GDL under an interconnector rib) is an important transport process for conventional SFFs, with its intensity being significantly enhanced as GDL permeability increases. The results also indicate that under rib convection can be significantly improved by employing MPSFFs as the reactant flow field, because of the closely interlaced structure of GC regions that have different path lengths from the inlet. However, reactant flow rate through GCs proportionally decreases as under rib convection intensity increases, suggesting that proper optimization is required between the flow velocity in GCs and the under rib convection intensity in GDLs
Single phase and two-phase flow pressure losses through restrictions, expansions and inserts
International Nuclear Information System (INIS)
Glenat, P.; Solignac, P.
1984-11-01
We give a selection of methods to predict pressure losses through retrictions, expansions and inserts. In single phase flow, we give the classical method based on the one-dimensional momentum and mass balances. In two-phase flow, we propose the method given by Harshe et al. and an empirical approach suggested by Chisholm. We notice the distinction between long and short inserts depends upon wether or not the vena contracta lies within insert. Finally, we propose three correlations to calculate void fraction through the singularities which have been considered [fr
Time-varying exchange rate pass-through: experiences of some industrial countries
Toshitaka Sekine
2006-01-01
This paper estimates exchange rate pass-through of six major industrial countries using a time-varying parameter with stochastic volatility model. Exchange rate pass-through is divided into impacts of exchange rate fluctuations to import prices (first-stage pass-through) and those of import price movements to consumer prices (second-stage pass-through). The paper finds that both stages of pass-through have declined over time for all the sample countries. The decline in second-stage pass-throu...
Marrone, Salvatore; Colagrossi, Andrea; Di Mascio, Andrea; Le Touzé, David
2016-05-01
The study of energetic free-surface flows is challenging because of the large range of interface scales involved due to multiple fragmentations and reconnections of the air-water interface with the formation of drops and bubbles. Because of their complexity the investigation of such phenomena through numerical simulation largely increased during recent years. Actually, in the last decades different numerical models have been developed to study these flows, especially in the context of particle methods. In the latter a single-phase approximation is usually adopted to reduce the computational costs and the model complexity. While it is well known that the role of air largely affects the local flow evolution, it is still not clear whether this single-phase approximation is able to predict global flow features like the evolution of the global mechanical energy dissipation. The present work is dedicated to this topic through the study of a selected problem simulated with both single-phase and two-phase models. It is shown that, interestingly, even though flow evolutions are different, energy evolutions can be similar when including or not the presence of air. This is remarkable since, in the problem considered, with the two-phase model about half of the energy is lost in the air phase while in the one-phase model the energy is mainly dissipated by cavity collapses.
LES of hypersonic flow over a 3D single-fin
Fang, J.; Yao, Y.; Lu, L.; Zheng, Y.
2015-01-01
LES of hypersonic flow passing a 3D single-fin at Mach 5 and Re∞=3.7×107/m was conducted using a newly developed 7th-order low-dissipation monotonicity-preserving NS solver with dynamic Smagorinsky subgrid model. The simulation captures salient flow phenome such as shock systems, flow separation structures, and turbulence characteristics. It was found that in the reverse flow region, the streamwise elongated coherent structures are regenerated beneath the main separation vortex, almost immedi...
Estimating the Exchange Rate Pass-Through to Prices in Mexico
Josué Fernando Cortés Espada
2013-01-01
This paper estimates the magnitude of the exchange rate pass-through to consumer prices in Mexico. Moreover, it analyzes if the pass-through dynamics have changed in recent years. In particular, it uses a methodology that generates results consistent with the hierarchy implicit in the cpi. The results suggest that the exchange rate pass-through to the general price level is low and not statistically significant. However, the pass-through is positive and significant for goods prices. Furthermo...
Directory of Open Access Journals (Sweden)
Minggao Tan
2018-01-01
Full Text Available As the key equipment in deep ocean mining, the slurry pump suffers from wear and blocking problems. In this paper, high-speed photography technique is applied to track the movement rule of single particle of the coarse particle solid–liquid two-phase flow in a double blade slurry pump. The influences of particle diameter and particle density on the pass-through and collision characteristics of particles are analyzed as well. The results show that the average of the passing pump time first decreases and then increases when the particle diameter increases. The average of the passing pump time decreases by 22.7%, when the particle density increases from 1.09 g/cm3 to 1.75 g/cm3. Besides, the particle density has great influence on the location where the particle hits the tongue. Most particles of 1.09 g/cm3 hit the tongue on the left side, while collision location of particles of 1.75 g/cm3 is mainly on the top and at the right side of the tongue. The research can provide a basis for the optimization design of slurry pump in deep ocean mining system.
An empirical study of exchange rate pass-through in China
Directory of Open Access Journals (Sweden)
Jin Xiaowen
2012-01-01
Full Text Available This paper seeks to estimate exchange rate pass-through in China and investigate its relationship with monetary policy. Linear and VAR models are applied to analyze robustness. The linear model shows that, over the long run, a 1% appreciation of NEER causes a decline in the CPI inflation rate of 0.132% and PPI inflation rate of 0.495%. The VAR model supports the results of the linear model, suggesting a fairly low CPI pass-through and relatively higher PPI pass-through. Furthermore, this paper finds that, with the fixed exchange rate regime, CPI pass-through remains higher. The exchange rate regimes influence on CPI pass through, combined with the fact that appreciation diminishes inflation, suggests that the Chinese government could pursue a more flexible exchange rate policy. In addition, reasons for low exchange rate pass-through for CPI are analyzed. The analysis considers price control, basket and weight of Chinese price indices, distribution cost, and imported and non-tradable share of inputs.
The Pass-Through of Exchange Rate Changes to Import Prices
Ketelsen, Uwe; Kortelainen, Mika
1996-01-01
In this paper we analyze the empirical relevance of exchange rate pass-through for Finland, Sweden and Denmark during the period 1980–1994. Further, we attempt to determine if there has been a structural change in the pass-through relationship in the1990s. We find that about half the changes in exchange rates and world prices are passed through to import prices within one year, and three-quarters of such changes are passed through to import prices in two years. Moreover, there are no major di...
Exchange rate pass-through in Switzerland: Evidence from vector autoregressions
Jonas Stulz
2007-01-01
This study investigates the pass-through of exchange rate and import price shocks to different aggregated prices in Switzerland. The baseline analysis is carried out with recursively identified vector autoregressive (VAR) models. The data set comprises monthly observations, and pass-through effects are quantified by means of impulse response functions. Evidence shows that the exchange rate pass-through to import prices is substantial (although incomplete), but only moderate to total consumer ...
Directory of Open Access Journals (Sweden)
Mateusz Hämmerling
2017-06-01
Full Text Available The article presents results of a field study of the fish pass located within the Skórka barrage on the Głomia river. The aim of the study was to identify water flow conditions in particular chambers of the fish pass. On the basis of results of the field study, the hydraulic conditions of water flow through the fish pass were determined and referred to the optimum performance parameters of the construction. The results obtained make a basis for discussion of possible problems related to construction and operation of the fish passes resembling „close to nature” structures.
Gain claming in single-pass and double-pass L-band erbium-doped fiber amplifiers
International Nuclear Information System (INIS)
Harun, S.W.; Ahmad, H.
2004-01-01
Gain clamping is demonstrated in single-pass and double-pass long wavelength band erbium-doped fiber amplifiers. A C/L-band wavelength division multiplexing coupler is used in single-pass system to generate a laser at 1566 nm. The gain for the amplifier is clamped at 15.5 dB with gain variation of less than 0.2 dB from input signal power of -40 to -14 dBm with almost negligible noise figure penalty. However, the flatness of gain spectrum is slightly degraded due to the un-optimisation of erbium-doped fiber length. The advantage of this configuration is that the oscillating light does not appear at the output of the amplifier. A highly efficient gain-clamped long wavelength band erbium-doped fiber amplifiers with improved noise figure characteristic is demonstrated by simply adding a broadband conventional band fiber Bragg grating in double pass system. The combination of the fiber Bragg grating and optical circulator has created laser in the cavity for gain clamping. By adjusting the power combination of pumps 1 and 2, the clamped gain level can be controlled. The amplifier gain is clamped at 28.1 dB from -40 to -25 dBm with gain variation of less than 0.5 dB by setting the pumps 1 and 2 at 59.5 and 50.6 mW, respectively. The gain is also flat from 1574 nm to 1604 nm with gain variation of less than 3 dB. The corresponding noise figure varies from 5.6 to 7.6 dB, which is 0.8 to 2.6 dB reduced compared to those of unclamped amplifier (Authors)
Pass-through of exchange rates and tariffs in Greek-US tobacco trade
Rezitis, Anthony N.; Brown, A. Blake
1999-01-01
The paper examines the extent to which exchange rate and unit tariff changes are passed-through in US import prices of unmanufactured Greek oriental tobacco. The results indicate partial pass-through of exchange rates and tariffs. Exchange rate pass-through is about 0.272 and tariff pass-through about 0.185. One possible reason for the partial pass-through is oligopoly in tobacco exporting. Oligopoly would imply that depreciation of the drachma relative to the US dollar benefits tobacco expor...
Time variation in European carbon pass-through rates in electricity futures prices
International Nuclear Information System (INIS)
Huisman, Ronald; Kiliç, Mehtap
2015-01-01
The European Union Emissions Trading Scheme is a means to price emission allowances. Electricity market prices should reflect these market prices of emission allowances as they are a cost factor for power producers. The pass-through rate is the fraction of the emission allowance price that is passed through to electricity market prices. It is often measured and presented as an average or a fixed estimate over some time period. However, we expect that the pass-through rates should actually vary over time as electricity supply curves reflect the marginal costs of different producers that differ in emission intensity. We apply a Kalman Filter approach to observe pass-through rates in Germany and U.K. and find strong support for time varying instead of fixed pass-through rates. Although policy makers are interested in the impact of a policy on average, our results indicate that one needs to be careful with the time-frame over which pass-through rates are measured for policy evaluation, as an incorrect chosen evaluation period could cause an under- or overestimation of the pass-through rate. In addition, our model helps to provide policy makers with insight in the development of pass-through rates when market circumstances change with respect to power production. - Highlights: • We analyse the time-variation of the emission pass-through rate in power prices. • We examine historical futures prices for Germany and the U.K. • We test the hypothesis by using the Kalman Filter methodology. • Strong support is found that pass-through rates vary over time. • The chosen time-frame for pass-through rates is important for policy evaluation.
Passing Current through Touching Molecules
DEFF Research Database (Denmark)
Schull, G.; Frederiksen, Thomas; Brandbyge, Mads
2009-01-01
The charge flow from a single C-60 molecule to another one has been probed. The conformation and electronic states of both molecules on the contacting electrodes have been characterized using a cryogenic scanning tunneling microscope. While the contact conductance of a single molecule between two...
Exchange rate pass-through and the role of international distribution channels
Desiraju, Ramarao; Shrikhande, Milind
1996-01-01
Manufacturers selling in foreign markets often do not completely pass on the effects of fluctuations in exchange rates to the prices of their products. Our paper addresses this puzzle and studies the effects of the international distribution channel on exchange rate pass-through. We develop an exchange rate pass-through model that takes into account the role of an intermediary between a domestic manufacturer and its consumers in a foreign market. We find that the magnitude of the pass-through...
Experimental and simulation studies on a single pass, double duct solar air heater
Energy Technology Data Exchange (ETDEWEB)
Forson, F.K. [Kwame Nkrumah Univ. of Science and Technology, Dept. of Mechanical Engineering, Kumasi (Ghana); Rajakaruna, H. [De Montfort Univ., School of Engineering and Technology, Leicester (United Kingdom)
2003-05-01
A mathematical model of a single pass, double duct solar air heater (SPDDSAH) is described. The model provides a design tool capable of predicting: incident solar radiation, heat transfer coefficients, mean air flow rates, mean air temperature and relative humidity at the exit. Results from the simulation are presented and compared with experimental ones obtained on a full scale air heater and a small scale laboratory one. Reasonable agreement between the predicted and measured values is demonstrated. Predicted results from a parametric study are also presented. It is shown that significant improvement in the SPDDSAH performance can be obtained with an appropriate choice of the collector parameters and the top to bottom channel depth ratio of the two ducts. The air mass flow rate is shown to be the dominant factor in determining the overall efficiency of the heater. (Author)
Highly efficient single-pass sum frequency generation by cascaded nonlinear crystals
DEFF Research Database (Denmark)
Hansen, Anders Kragh; Andersen, Peter E.; Jensen, Ole Bjarlin
2015-01-01
, despite differences in the phase relations of the involved fields. An unprecedented 5.5 W of continuous-wave diffraction-limited green light is generated from the single-pass sum frequency mixing of two diode lasers in two periodically poled nonlinear crystals (conversion efficiency 50%). The technique......The cascading of nonlinear crystals has been established as a simple method to greatly increase the conversion efficiency of single-pass second-harmonic generation compared to a single-crystal scheme. Here, we show for the first time that the technique can be extended to sum frequency generation...... is generally applicable and can be applied to any combination of fundamental wavelengths and nonlinear crystals....
Study of two-phase flow redistribution between two passes of a heat exchanger
International Nuclear Information System (INIS)
Mendes de Moura, L.F.
1989-04-01
The object of the present thesis deals with the study of two-phase flow redistribution between two passes of a heat exchanger. Mass flow rate measurements of each component performed at each channel outlet of the second pass allowed us to determine the influence of mass flow, gas quality, flow direction (upward or downward) and common header geometry upon flow redistribution. Local void fraction inside common header was measured with an optical probe. A two-dimensional two-phase flow computational code was developed from a two-fluid model. Modelling of interfacial momentum transfer was used in order to take into account twp-phase flow patterns in common headers. Numerical simulation results show qualitative agreement with experimental results. Present theoretical model limitations are analysed and future improvements are proposed [fr
An Empirical Study of Exchange Rate Pass-Through in China
Xiaowen Jin
2012-01-01
This paper seeks to estimate exchange rate pass-through in China and investigate its relationship with monetary policy. Linear and VAR models are applied to analyze robustness. The linear model shows that, over the long run, a 1% appreciation of NEER causes a decline in the CPI inflation rate of 0.132% and PPI inflation rate of 0.495%. The VAR model supports the results of the linear model, suggesting a fairly low CPI pass-through and relatively higher PPI pass-through. Furthermore, thi...
Own-Brand and Cross-Brand Retail Pass-Through
David Besanko; Jean-Pierre Dubé; Sachin Gupta
2005-01-01
In this paper we describe the pass-through behavior of a major U.S. supermarket chain for 78 products across 11 categories. Our data set includes retail prices and wholesale prices for stores in 15 retail price zones for a one-year period. For the empirical model, we use a reduced-form approach that focuses directly on equilibrium prices as a function of exogenous supply- and demand-shifting variables. The reduced-form approach enables us to identify the theoretical pass-through rate without ...
Vijayanand, V. D.; Vasudevan, M.; Ganesan, V.; Parameswaran, P.; Laha, K.; Bhaduri, A. K.
2016-06-01
Creep deformation and rupture behavior of single-pass and dual-pass 316LN stainless steel (SS) weld joints fabricated by an autogenous activated tungsten inert gas welding process have been assessed by performing metallography, hardness, and conventional and impression creep tests. The fusion zone of the single-pass joint consisted of columnar zones adjacent to base metals with a central equiaxed zone, which have been modified extensively by the thermal cycle of the second pass in the dual-pass joint. The equiaxed zone in the single-pass joint, as well as in the second pass of the dual-pass joint, displayed the lowest hardness in the joints. In the dual-pass joint, the equiaxed zone of the first pass had hardness comparable to the columnar zone. The hardness variations in the joints influenced the creep deformation. The equiaxed and columnar zone in the first pass of the dual-pass joint was more creep resistant than that of the second pass. Both joints possessed lower creep rupture life than the base metal. However, the creep rupture life of the dual-pass joint was about twofolds more than that of the single-pass joint. Creep failure in the single-pass joint occurred in the central equiaxed fusion zone, whereas creep cavitation that originated in the second pass was blocked at the weld pass interface. The additional interface and strength variation between two passes in the dual-pass joint provides more restraint to creep deformation and crack propagation in the fusion zone, resulting in an increase in the creep rupture life of the dual-pass joint over the single-pass joint. Furthermore, the differences in content, morphology, and distribution of delta ferrite in the fusion zone of the joints favors more creep cavitation resistance in the dual-pass joint over the single-pass joint with the enhancement of creep rupture life.
An estimation of the exchange rate pass-through to prices in Mexico
Josué Fernando Cortés Espada
2013-01-01
This paper estimates the magnitude of the exchange rate pass-through to consumer prices in Mexico. Moreover, it analyzes if the pass-through dynamics have changed in recent years. In particular, it uses a methodology that generates results consistent with the hierarchy implicit in the CPI. The results suggest that the exchange rate pass-through to the general price level is low and not statistically significant. However, the pass-through is positive and significant for goods prices. Furthermo...
Axioms for behavioural congruence of single-pass instruction sequences
Bergstra, J.A.; Middelburg, C.A.
2017-01-01
In program algebra, an algebraic theory of single-pass instruction sequences, three congruences on instruction sequences are paid attention to: instruction sequence congruence, structural congruence, and behavioural congruence. Sound and complete axiom systems for the first two congruences were
Delay Bound: Fractal Traffic Passes through Network Servers
Directory of Open Access Journals (Sweden)
Ming Li
2013-01-01
Full Text Available Delay analysis plays a role in real-time systems in computer communication networks. This paper gives our results in the aspect of delay analysis of fractal traffic passing through servers. There are three contributions presented in this paper. First, we will explain the reasons why conventional theory of queuing systems ceases in the general sense when arrival traffic is fractal. Then, we will propose a concise method of delay computation for hard real-time systems as shown in this paper. Finally, the delay computation of fractal traffic passing through severs is presented.
The structure of single-phase turbulent flows through closely spaced rod arrays
International Nuclear Information System (INIS)
Hooper, J.D.; Rehme, K.
1983-02-01
The axial and azimuthal turbulence intensity in the rod gap region has been shown, for developed single-phase turbulent flow through parallel rod arrays, to strongly increase with decreasing rod spacing. Two array geometries are reported, one constructed from a rectangular cross-section duct containing four rods and spaced at five p/d or w/d ratios. The second test section, constructed from six rods set in a regular square-pitch array, represented the interior flow region of a large array. The mean axial velocity, wall shear stress variation and axial pressure distribution were measured, together with hot-wire anemometer measurements of the Reynolds stresses. No significant non-zero secondary flow components were detected, using techniques capable of resolving secondary flow velocities to 1% of the local axial velocity. For the lowest p/d ratio of 1.036, cross-correlation measurements showed the presence of an energetic periodic azimuthal turbulent velocity component, correlated over a significant part of the flow area. The negligible contribution of secondary flows to the axial momentum balance, and the large azimuthal turbulent velocity component in the rod gap area, suggest a different mechanism than Reynolds stress gradient driven secondary flows for the turbulent transport process in the rod gap. (orig.) [de
Single Pass Albumin Dialysis in Hepatorenal Syndrome
Directory of Open Access Journals (Sweden)
Rahman Ebadur
2008-01-01
Full Text Available Hepatorenal syndrome (HRS is the most appalling complication of acute or chronic liver disease with 90% mortality rate. Single pass albumin dialysis (SPAD can be considered as a noble liver support technique in HRS. Here, we present a case of a young healthy patient who developed hyperacute fulminant liver failure that progressed to HRS. The patient was offered SPAD as a bridge to liver transplantation, however, it resulted in an excellent recovery.
Experimental analysis of humidification process by air passing through seawater
International Nuclear Information System (INIS)
El-Agouz, S.A.; Abugderah, M.
2008-01-01
An experimental investigation of humidification process by air passing through seawater is presented. The main objective of this work was to determine the humid air behaviour through single-stage of heating-humidifying processes. This experimental work studied the influence of the operating conditions such as the water temperature, the headwater difference, the air velocity and the inlet air temperature to evaporator chamber on the vapour content difference and humidification efficiency. Two cases of different inlet conditions of ambient and heated air cases are studied. The experimental results show that, the vapour content difference and the humidification efficiency of the system is strongly affected by the saline water temperature in the evaporator chamber, headwater difference and the air velocity. The inlet air temperature to evaporator chamber variation was found to have a small affect on the vapour content difference. The obtained maximum vapour content difference of the air was about 222 gr w /kg a at 75 deg. C for water and air. The obtained vapour content is high compared to that obtained in literature for single-stage and very similar for multi-stage
Flow through a very porous obstacle in a shallow channel.
Creed, M J; Draper, S; Nishino, T; Borthwick, A G L
2017-04-01
A theoretical model, informed by numerical simulations based on the shallow water equations, is developed to predict the flow passing through and around a uniform porous obstacle in a shallow channel, where background friction is important. This problem is relevant to a number of practical situations, including flow through aquatic vegetation, the performance of arrays of turbines in tidal channels and hydrodynamic forces on offshore structures. To demonstrate this relevance, the theoretical model is used to (i) reinterpret core flow velocities in existing laboratory-based data for an array of emergent cylinders in shallow water emulating aquatic vegetation and (ii) reassess the optimum arrangement of tidal turbines to generate power in a tidal channel. Comparison with laboratory-based data indicates a maximum obstacle resistance (or minimum porosity) for which the present theoretical model is valid. When the obstacle resistance is above this threshold the shallow water equations do not provide an adequate representation of the flow, and the theoretical model over-predicts the core flow passing through the obstacle. The second application of the model confirms that natural bed resistance increases the power extraction potential for a partial tidal fence in a shallow channel and alters the optimum arrangement of turbines within the fence.
International Nuclear Information System (INIS)
Alger, D.L.
1975-01-01
A neutron emitting target is described for use in neutron generating apparatus including a deuteron source and an accelerator vacuum chamber. The target consists of a tritium-containing target layer, a deuteron accumulation layer, and a target support containing passages providing communication between the accumulation layer and portions of the surface of the support exposed to the accelerator vacuum chamber. With this arrangement, deuterons passing through the target layer and implanting in and diffusing through the accumulation layer, diffuse into the communicating passages and are returned to the accelerator vacuum chamber. The invention allows the continuous removal of deuterons from the target in conventional water cooled neutron generating apparatus. Preferably, the target is provided with thin barrier layers to prevent undesirable tritium diffusion out of the target layer, as well as deuteron diffusion into the target layer
Pass-through of Change in Policy Interest Rate to Market Rates
M. Idrees Khawaja; Sajawal Khan
2008-01-01
This paper examines the pass through of the change in policy interest rate of the central bank of Pakistan to market interest rates. The market rates examined include KIBOR, six month deposit rate and weighted average lending rate. More or less complete pass-through of the change in policy rate to KIBOR is observed within one month. However, the magnitude of change in policy rate to deposit and lending rate is not only low but is slow as well. The pass-through to the weighted average lending ...
Pass-through of crude oil prices at different stages in Turkey
Directory of Open Access Journals (Sweden)
Fatih Akçelik
2016-03-01
Full Text Available This paper examines the degree of oil price pass-through to domestic prices at different stages of supply chain in Turkey. Our results, based on vector autoregressive models, point out that the pass-through to domestic motor fuel prices is considerably fast as expected and just one third of a change in crude oil prices is reflected to the motor fuel prices due to the high share of taxes on retail prices. On the other hand, it is shown that impact of oil prices on transport services takes a longer time compared to other domestic prices. Over the 2004–2014 period, estimates suggest that a 10% permanent change in the international crude oil prices is associated with a 0.42 percentage points change in consumer inflation at the end of one year. The final accumulated pass-through to consumer inflation reaches 0.50 percentage points. Moreover, the pass-through to producer prices is nearly twice as much as that to consumer prices. Findings also provide some evidence for a strengthening in oil price pass-through to consumer inflation over time, which might reflect the growing natural gas intensity of the economy.
Directory of Open Access Journals (Sweden)
Mateusz Hammerling
2016-04-01
Full Text Available The aim of the article is to analyse hydraulic conditions of water flow in a fish pass. The test facility is part of the Pomiłowo barrage in the commune of Sławno, Poland. The authors applied HEC-RAS software for modelling hydraulic parameters of the water flow in the fish pass. The data from field measurements was implemented in the software and calculations of changes in the water table in the fish pass were made. The results confirmed the usefulness of HEC-RAS software for estimating hydraulic parameters of water flow in a fish pass. HEC-RAS software enables to take into account the parameters responsible for the phenomena accompanying the flow through a fish pass. Selecting mathematical model parameters (coefficients should be preceded by a multidimensional analysis of the facility. More precise information on hydraulics, hydrology and biology of the test fish pass are also required.
Clogging and unclogging of many-particle systems passing through a bottleneck
Directory of Open Access Journals (Sweden)
Zuriguel Iker
2017-01-01
Full Text Available When a group of discrete particles pass through a narrowing, the flow may become arrested due to the development of structures that span over the size of the aperture. Then, it is said that the system is clogged. Here, we will discuss about the existence of a phase diagram for the clogged state that has been recently proposed, arguing on its usefulness to describe different systems of discrete bodies ranging from granular materials, to colloidal suspensions and live beings. This diagram is built based on the value of a flowing parameter which characterizes the intermittent flow observed in all these discrete systems provided that there is an external or internal energy supply. Such requirement, which is necessary to destabilize the clogging arches, is absent in a standard static silo, which is therefore examined as a particular case. This view will help to understand some a priori inconsistencies concerning the role of driving force in the clogging process that have been found in the last years.
Forest Analysis by Single-Pass Millimeterwave SAR Tomography
Schmitt, Michael; Zhu, Xiao Xiang
2016-01-01
Recent investigations show that millimeterwave SAR tomography provides an interesting means for the analysis of forested areas, especially if single-pass systems are employed. Providing very high resolutions in the decimeter domain and highly coherent data also for slightly windy conditions, even individual trees can be considered. Besides, it has been shown that a certain amount of canopy penetration is possible in spite of the short wavelength.
Numerical simulations of seepage flow in rough single rock fractures
Directory of Open Access Journals (Sweden)
Qingang Zhang
2015-09-01
Full Text Available To investigate the relationship between the structural characteristics and seepage flow behavior of rough single rock fractures, a set of single fracture physical models were produced using the Weierstrass–Mandelbrot functions to test the seepage flow performance. Six single fractures, with various surface roughnesses characterized by fractal dimensions, were built using COMSOL multiphysics software. The fluid flow behavior through the rough fractures and the influences of the rough surfaces on the fluid flow behavior was then monitored. The numerical simulation indicates that there is a linear relationship between the average flow velocity over the entire flow path and the fractal dimension of the rough surface. It is shown that there is good a agreement between the numerical results and the experimental data in terms of the properties of the fluid flowing through the rough single rock fractures.
Water flow in single rock joints
International Nuclear Information System (INIS)
Hakami, Eva
1989-05-01
To study the hydromechanical properties of single rock joints a technique to make transparent replicas of natural joint surfaces has been developed. Five different joint samples were replicated and studied. The aperture distribution of the joints were obtained through a measurement method provided by the transparent replicas. The principle behind the method is that a water drop with a known volume, which is placed inside a joint, will cover a certain area of the surface depending on the average size of aperture at the actual point. Flow tests were performed on the same joint replicas. The tortuousity of the flow and the velocity along single stream lines were measured using colour injections into the water flow through the joints. The equivalent hydraulic apertures determined from the flow tests where shown to be smaller than the average mechanical apertures. The velocity of the flow varies strongly between different paths over the joint depending on the spatial distribution of the apertures. The degree of matedness between the joint surfaces is an important factor influencing the channeling character of the joints. (author) (38 refs.)
Mechanism of falling water limitation in two-phase counter flow through single hole vertical channel
International Nuclear Information System (INIS)
Sudo, Yukio; Ohnuki, Akira
1983-01-01
In the safety evaluation at the time of loss coolant accident, which is a credible accident in LWRs, recently main effort has been concentrated to the optimum evaluation calculation, and the grasp of vapor-liquid two-phase flow phenomena has become important. As one of the important phenomena, there is the limitation of falling water in two-phase counter flow through a vertical channel. This phenomenon is divided into the limitation of falling water stored in an upper plenum to a core through an upper core-supporting plate and a tie plate at the time of reflooding, and the limitation of falling emergency core-cooling water in downcomer channels at the time of reflooding in PWRs, under the presence of rising steam flow. In both cases, the evaluation of the quantity of falling water is important, because it contributes directly to core cooling. In this research, in order to clarify the mechanism of limitation of falling water in two-phase vertical counter flow, first, two-phase flow of air-water system through a single-hole vertical channel was taken up, and the effect of main parameters was experimentally studied. At the same time, the theoretical investigation was performed, and the comparison with the experimental results obtained so far was carried out. The different mechanisms for short and long channels gave the good results. (Kako, I.)
Number of Migration Scenarios Passing through each HUC
U.S. Environmental Protection Agency — Forest dwelling neotropical migratory birds require intact forested stopovers during migration. The number of paths that pass through a HUC highlight that huc's...
International Nuclear Information System (INIS)
Stefanovsky, S.V.; Varlakova, G.A.; Burlaka, O.A.; Stefanovsky, O.I.; Nikonov, B.S.; Yudintsev, S.V.
2009-01-01
Two samples of murataite-based ceramics containing simulated Actinide/Rare Earth (An/RE) fraction of high level waste (HLW) produced by a cold crucible inductive melting (CCIM) were tested using a single-pass-flow-through (SPFT) procedure. As-prepared and leached samples were examined by X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive system (SEM/EDS). The as-prepared ceramics were composed of murataite, perovskite and crichtonite as well as minor zirconolite and rutile (in one sample). Elemental concentrations at pH=2 and T=90 deg. C were measured and leach rates were calculated. Perovskite concentrating Ca and Ce-group REs (La, Ce, Pr, Nd) was found to be the lowest durable phase. Leach rates of Ca and Ce-group REs (Ce, Nd) from the sample with higher perovskite content were found to be higher than those of U and Zr by one to three orders of magnitude. Elemental leach rates from the ceramic with lower perovskite content are lower by up to 10 times. (authors)
Photoacoustic Soot Spectrometer (PASS) Instrument Handbook
Energy Technology Data Exchange (ETDEWEB)
Dubey, M [Los Alamos National Laboratory; Springston, S [Brookhaven National Laboratory; Koontz, A [Pacific Northwest National Laboratory; Aiken, A [Los Alamos National Laboratory
2013-01-17
The photoacoustic soot spectrometer (PASS) measures light absorption by aerosol particles. As the particles pass through a laser beam, the absorbed energy heats the particles and in turn the surrounding air, which sets off a pressure wave that can be detected by a microphone. The PASS instruments deployed by ARM can also simultaneously measure the scattered laser light at three wavelengths and therefore provide a direct measure of the single-scattering albedo. The Operator Manual for the PASS-3100 is included here with the permission of Droplet Measurement Technologies, the instrument’s manufacturer.
Incentive Pass-through for Residential Solar Systems in California
Energy Technology Data Exchange (ETDEWEB)
Dong, C. G. [Univ. of Texas, Austin, TX (United States); Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rai, Varun [Univ. of Texas, Austin, TX (United States)
2014-10-01
The deployment of solar photovoltaic (PV) systems has grown rapidly over the last decade, partly because of various government incentives. In the United States, among the largest and longest-running incentives have been those established in California. Building on past research, this report addresses the still-unanswered question: to what degree have the direct PV incentives in California been passed through from installers to consumers? This report helps address this question by carefully examining the residential PV market in California (excluding a certain class of third-party-owned PV systems) and applying both a structural-modeling approach and a reduced-form regression analysis to estimate the incentive pass-through rate. The results suggest an average pass-through rate of direct incentives of nearly 100%, though with regional differences among California counties. While these results could have multiple explanations, they suggest a relatively competitive market and well-functioning subsidy program. Further analysis is required to determine whether similar results broadly apply to other states, to other customer segments, to all third-party-owned PV systems, or to all forms of financial incentives for solar (considering not only direct state subsidies, but also utility electric bill savings and federal tax incentives).
Message-Passing Receivers for Single Carrier Systems with Frequency-Domain Equalization
DEFF Research Database (Denmark)
Zhang, Chuanzong; Manchón, Carles Navarro; Wang, Zhongyong
2015-01-01
In this letter, we design iterative receiver algorithms for joint frequency-domain equalization and decoding in a single carrier system assuming perfect channel state information. Based on an approximate inference framework that combines belief propagation (BP) and the mean field (MF) approximation......, we propose two receiver algorithms with, respectively, parallel and sequential message-passing schedules in the MF part. A recently proposed receiver based on generalized approximate message passing (GAMP) is used as a benchmarking reference. The simulation results show that the BP-MF receiver...
BRANCH JUNCTIONS AND THE FLOW OF WATER THROUGH XYLEM IN DOUGLAS-FIR AND PONDEROSA PINE STEMS
Water flowing through the xylem of most plants from the roots to the leaves must pass through junctions where branches have developed from the main stem. These junctions have been studied as both flow constrictions and components of a hydraulic segmentation mechanism to protect ...
Regional Myocardial Blood Volume and Flow: First-Pass MR Imaging with Polylysine-Gd-DTPA
Wilke, Norbert; Kroll, Keith; Merkle, Hellmut; Wang, Ying; Ishibashi, Yukata; Xu, Ya; Zhang, Jiani; Jerosch-Herold, Michael; Mühler, Andreas; Stillman, Arthur E.; Bassingthwaighte, James B.; Bache, Robert; Ugurbil, Kamil
2010-01-01
The authors investigated the utility of an intravascular magnetic resonance (MR) contrast agent, poly-L-lysine-gadolinium diethylenetriaminepentaacetic acid (DTPA), for differentiating acutely ischemic from normally perfused myocardium with first-pass MR imaging. Hypoperfused regions, identified with microspheres, on the first-pass images displayed significantly decreased signal intensities compared with normally perfused myocardium (P < .0007). Estimates of regional myocardial blood content, obtained by measuring the ratio of areas under the signal intensity-versus-time curves in tissue regions and the left ventricular chamber, averaged 0.12 mL/g ± 0.04 (n = 35), compared with a value of 0.11 mL/g ± 0.05 measured with radiolabeled albumin in the same tissue regions. To obtain MR estimates of regional myocardial blood flow, in situ calibration curves were used to transform first-pass intensity-time curves into content-time curves for analysis with a multiple-pathway, axially distributed model. Flow estimates, obtained by automated parameter optimization, averaged 1.2 mL/min/g ± 0.5 [n = 29), compared with 1.3 mL/min/g ± 0.3 obtained with tracer microspheres in the same tissue specimens at the same time. The results represent a combination of T1-weighted first-pass imaging, intravascular relaxation agents, and a spatially distributed perfusion model to obtain absolute regional myocardial blood flow and volume. PMID:7766986
exchange rate pass-through to import and consumer prices
African Journals Online (AJOL)
Eyerusalem
degree of pass-through is estimated by the means of impulse response functions. ..... through from exchange rate fluctuations to each stage of the distribution chain ..... exclusion test (which is asymptotically chi-square distributed) and the results ...... Endogenous variables: DLWCPI YGap DLNEER DLMPI DLCPI DLM2. Root.
EXCHANGE RATE PASS-THROUGH, IMPORT PRICES AND INFLATION UNDER STRUCTURAL BREAKS
Directory of Open Access Journals (Sweden)
Arintoko Arintoko
2011-09-01
Full Text Available This research estimates the exchange rate pass-through (ERPT into import prices by applying an extension of the basic model of ERPT on Indonesia. It estimates models of cointegration and error-correction mechanism (ECM, with and without structural breaks. It uses the techniques of Zivot-Andrews and of Gregory-Hansen to test for structural breaks and cointegration with the structural breaks, respectively. The results show that with the control variables, inflation affects import prices and lower the pass-through for short term, in a condition of free floating exchange rate. In the short term, with the inclusion of structural breaks, significant inflation affects import prices and lowers the ERPT coefficient. Keywords: Exchange rate pass-through, inflation, structural breaks, cointegration, error-correction mechanismJEL classification numbers: C22, C32, E31, F41
Number of Migration Scenarios Passing through each HUC (future)
U.S. Environmental Protection Agency — Forest dwelling neotropical migratory birds require intact forested stopovers during migration. The number of paths that pass through a HUC highlight that huc's...
Pass-transistor asynchronous sequential circuits
Whitaker, Sterling R.; Maki, Gary K.
1989-01-01
Design methods for asynchronous sequential pass-transistor circuits, which result in circuits that are hazard- and critical-race-free and which have added degrees of freedom for the input signals, are discussed. The design procedures are straightforward and easy to implement. Two single-transition-time state assignment methods are presented, and hardware bounds for each are established. A surprising result is that the hardware realizations for each next state variable and output variable is identical for a given flow table. Thus, a state machine with N states and M outputs can be constructed using a single layout replicated N + M times.
Collective behavior of mice passing through an exit under panic
Zhang, Teng; Zhang, Xuelin; Huang, Shenshi; Li, Changhai; Lu, Shouxiang
2018-04-01
Collective movement of animal in emergency condition has attracted growing attentions among researchers. However, many rules still need to be confirmed with adequate explanation. Study of collective behavior of mice can improve our understanding about the dynamics of pedestrian movement. However, its rules still need to be confirmed with adequate explanation. In this paper, collective behavior of mice passing through an exit under panic was investigated. The results showed that the total evacuation time decreased with exit width increasing in a certain range. Based on the different tendency of the curve in temporal evolution, the process of mice flow was divided into three stages. The density of mice near the exit peaks at a certain horizontal offset and starts to decrease over time. With the increase of the exit width, the duration of the higher density state decreased. We found that the frequency of time intervals obeyed a lognormal distribution or an exponential decay for different exit widths. In addition, the relationship between the group size and the group flow rate in different scenarios was analyzed. The phenomena found in our experiments show the collective behavioral characteristic of mice under panic. Our analysis in this paper will deepen our understanding of crowd dynamics in emergency condition.
International Nuclear Information System (INIS)
Supa-Amornkul, S.; Lister, D.H.; Steward, F.R.
2005-01-01
'Full text:' In CANDU-6 reactors, the pressurized high-temperature coolant flows through 380 fuel channels passing horizontally through the core. Each end of a fuel channel has a stainless steel annular end-fitting connected to a carbon steel feeder pipe. The outlet coolant, which is at 310 o C with up to 0.30 steam voidage, turns through 90 o as it passes from flow in the annular end-fitting to pipe flow in the feeder via a Grayloc connector. Since 1996, several CANDU stations have reported excessive corrosion of their outlet feeder pipes; especially between the first metre, which consisted of single or double bends. Early studies related the attack to the hydrodynamics of the coolant and verified that it was a type of flow accelerated corrosion. In order to understand the hydrodynamics of the coolant in the outlet feeders by flow-visualization, a full-scale transparent test section simulating the geometry and orientation of an outlet feeder bend with its upstream annular end-fitting were fabricated. The feeder consisted of a 54 mm inside diameter acrylic pipe with a 73 o bend, connecting to an acrylic simulation of a Grayloc flanged fitting and annular end-fitting. The annular end-fitting consisted of an inner pipe, 110 mm outer diameter, and an outer pipe, 150 mm inner diameter, both 190.7 cm long in length. The tests were performed with water and air at atmospheric pressure and room temperature. The maximum water volumetric flow rate was 19 L/s and the volume fraction of air varied from 0.05 to 0.56. The phase distributions within the feeder pipe and along the length of the annulus were investigated with a digital video recorder. Size, concentration and velocity of the air bubbles at particular locations were studied with a high-speed digital still camera and a high-speed digital video camera. Phase distributions and variations in bubble size with velocity were determined. Particular attention was paid to the flow pattern at the inside of the bend, where a CFD
Energy Technology Data Exchange (ETDEWEB)
Supa-Amornkul, S.; Lister, D.H.; Steward, F.R. [Univ. of New Brunswick, Fredericton, New Brunswick (Canada)]. E-mail: h796e@unb.ca; dlister@unb.ca; fsteward@unb.ca
2005-07-01
'Full text:' In CANDU-6 reactors, the pressurized high-temperature coolant flows through 380 fuel channels passing horizontally through the core. Each end of a fuel channel has a stainless steel annular end-fitting connected to a carbon steel feeder pipe. The outlet coolant, which is at 310{sup o}C with up to 0.30 steam voidage, turns through 90{sup o} as it passes from flow in the annular end-fitting to pipe flow in the feeder via a Grayloc connector. Since 1996, several CANDU stations have reported excessive corrosion of their outlet feeder pipes; especially between the first metre, which consisted of single or double bends. Early studies related the attack to the hydrodynamics of the coolant and verified that it was a type of flow accelerated corrosion. In order to understand the hydrodynamics of the coolant in the outlet feeders by flow-visualization, a full-scale transparent test section simulating the geometry and orientation of an outlet feeder bend with its upstream annular end-fitting were fabricated. The feeder consisted of a 54 mm inside diameter acrylic pipe with a 73{sup o} bend, connecting to an acrylic simulation of a Grayloc flanged fitting and annular end-fitting. The annular end-fitting consisted of an inner pipe, 110 mm outer diameter, and an outer pipe, 150 mm inner diameter, both 190.7 cm long in length. The tests were performed with water and air at atmospheric pressure and room temperature. The maximum water volumetric flow rate was 19 L/s and the volume fraction of air varied from 0.05 to 0.56. The phase distributions within the feeder pipe and along the length of the annulus were investigated with a digital video recorder. Size, concentration and velocity of the air bubbles at particular locations were studied with a high-speed digital still camera and a high-speed digital video camera. Phase distributions and variations in bubble size with velocity were determined. Particular attention was paid to the flow pattern at the inside
The force on an object passing through a magnetic fluid seal
Morton, G
2002-01-01
Forces on solid objects passed through a magnetic liquid plug in a tube are measured. A simple one-dimensional model is developed based on hydrostatic and magnetic pressures. The results demonstrate its potential to be used to separate two fluids while allowing solids to pass from one fluid to the other.
Measurement of flow by-passing and turbulent mixing in a model of a fast-reactor steam generator
International Nuclear Information System (INIS)
Little, A.J.; Fallows, T.; Central Electricity Generating Board, Leatherhead
1989-01-01
A description is given of measurements of edge by-pass velocities and turbulent mixing in a model of a fast reactor steam generator. The velocity measurements were carried out using a DANTEC triple-split fibre probe which allowed both the speed and flow angle of a velocity vector to be measured in a plane normal to the axis of the probe. The measurements revealed the presence of reverse flows in the by-pass and adjacent in-bank channels downstream of a grid plate. The magnitude of the by-pass flow was reduced considerably by the insertion of a kicker grid at the mid point between grid plates. Turbulent mixing measurements revealed that circumferential mixing in channels near the by-pass channel was up to 5 times greater than the radial mixing. The level of radial mixing at the edge of the bank was similar to that measured near the centre of the bank. A method of transposing mass diffusion measurements in air to thermal diffusivities of sodium is discussed. (orig.)
Is a more stable exchange rate associated with reduced exchange rate pass-through?
Mark J. Holmes
2007-01-01
Pass-through from the nominal effective exchange rate to import prices is modelled within a regime-switching environment. Evidence suggests that exchange rate pass through can be characterised as regime-specific where the probability of switching between regimes is influenced by the extent of exchange rate volatility.
A mathematical model for turbulent incompressible flows through mixing grids
International Nuclear Information System (INIS)
Allaire, G.
1989-01-01
A mathematical model is proposed for the computation of turbulent incompressible flows through mixing grids. This model is obtained as follows: in a three-dimentional-domain we represent a mixing grid by small identical wings of size ε 2 periodically distributed at the nodes of a plane regular mesh of size ε, and we consider incompressible Navier-Stokes equations with a no-slip condition on the wings. Using an appropriate homogenization process we pass to the limit when ε tends to zero and we obtain a Brinkman equation, i.e. a Navier-Stokes equation plus a zero-order term for the velocity, in a homogeneous domain without anymore wings. The interest of this model is that the spatial discretization is simpler in a homogeneous domain, and, moreover, the new term, which expresses the grid's mixing effect, can be evaluated with a local computation around a single wing
Survival and Passage of Juvenile Chinook Salmon and Steelhead Passing through Bonneville Dam, 2010
Energy Technology Data Exchange (ETDEWEB)
Ploskey, Gene R.; Weiland, Mark A.; Hughes, James S.; Woodley, Christa M.; Deng, Zhiqun; Carlson, Thomas J.; Kim, Jin A.; Royer, Ida M.; Batten, George W.; Cushing, Aaron W.; Carpenter, Scott M.; Etherington, D. J.; Faber, Derrek M.; Fischer, Eric S.; Fu, Tao; Hennen, Matthew J.; Mitchell, Tyler; Monter, Tyrell J.; Skalski, John R.; Townsend, Richard L.; Zimmerman, Shon A.
2011-12-01
Pacific Northwest National Laboratory (PNNL) and subcontractors conducted an acoustic-telemetry study of juvenile salmonid fish passage and survival at Bonneville Dam in 2010. The study was conducted to assess the readiness of the monitoring system for official compliance studies under the 2008 Biological Opinion and Fish Accords and to assess performance measures including route-specific fish passage proportions, travel times, and survival based upon a single-release model. This also was the last year of evaluation of effects of a behavioral guidance device installed in the Powerhouse 2 forebay. The study relied on releases of live Juvenile Salmon Acoustic Telemetry System tagged smolts in the Columbia River and used acoustic telemetry to evaluate the approach, passage, and survival of passing juvenile salmon. This study supports the U.S. Army Corps of Engineers continual effort to improve conditions for juvenile anadromous fish passing through Columbia River dams.
Survival and Passage of Juvenile Chinook Salmon and Steelhead Passing Through Bonneville Dam, 2010
Energy Technology Data Exchange (ETDEWEB)
Ploskey, Gene R.; Weiland, Mark A.; Hughes, James S.; Woodley, Christa M.; Deng, Zhiqun; Carlson, Thomas J.; Kim, Jin A.; Royer, Ida M.; Batten, George W.; Cushing, Aaron W.; Carpenter, Scott M.; Etherington, D. J.; Faber, Derrek M.; Fischer, Eric S.; Fu, Tao; Hennen, Matthew J.; Mitchell, T. D.; Monter, Tyrell J.; Skalski, J. R.; Townsend, Richard L.; Zimmerman, Shon A.
2012-09-01
Pacific Northwest National Laboratory (PNNL) and subcontractors conducted an acoustic-telemetry study of juvenile salmonid fish passage and survival at Bonneville Dam in 2010. The study was conducted to assess the readiness of the monitoring system for official compliance studies under the 2008 Biological Opinion and Fish Accords and to assess performance measures including route-specific fish passage proportions, travel times, and survival based upon a single-release model. This also was the last year of evaluation of effects of a behavioral guidance device installed in the Powerhouse 2 forebay. The study relied on releases of live Juvenile Salmon Acoustic Telemetry System tagged smolts in the Columbia River and used acoustic telemetry to evaluate the approach, passage, and survival of passing juvenile salmon. This study supports the U.S. Army Corps of Engineers continual effort to improve conditions for juvenile anadromous fish passing through Columbia River dams.
A 3D Reconstruction Strategy of Vehicle Outline Based on Single-Pass Single-Polarization CSAR Data.
Leping Chen; Daoxiang An; Xiaotao Huang; Zhimin Zhou
2017-11-01
In the last few years, interest in circular synthetic aperture radar (CSAR) acquisitions has arisen as a consequence of the potential achievement of 3D reconstructions over 360° azimuth angle variation. In real-world scenarios, full 3D reconstructions of arbitrary targets need multi-pass data, which makes the processing complex, money-consuming, and time expending. In this paper, we propose a processing strategy for the 3D reconstruction of vehicle, which can avoid using multi-pass data by introducing a priori information of vehicle's shape. Besides, the proposed strategy just needs the single-pass single-polarization CSAR data to perform vehicle's 3D reconstruction, which makes the processing much more economic and efficient. First, an analysis of the distribution of attributed scattering centers from vehicle facet model is presented. And the analysis results show that a smooth and continuous basic outline of vehicle could be extracted from the peak curve of a noncoherent processing image. Second, the 3D location of vehicle roofline is inferred from layover with empirical insets of the basic outline. At last, the basic line and roofline of the vehicle are used to estimate the vehicle's 3D information and constitute the vehicle's 3D outline. The simulated and measured data processing results prove the correctness and effectiveness of our proposed strategy.
International Nuclear Information System (INIS)
Hayashi, Minoru; Kobayashi, Hidenori; Kawano, Hirokazu; Handa, Yuji; Noguchi, Yoshiyuki; Shirasaki, Naoki; Hirose, Satoshi
1986-01-01
The authors studied brain blood flow with single photon emission computed tomography (SPECT) in two patients with plateau waves. The intracranial pressure and blood pressure were also monitored continuously in these patients. They included one patient with brain-tumor (rt. sphenoid ridge meningioma) and another with hydrocephalus after subarachnoid hemorrhage due to rupture of lt. internal carotid aneurysm. The intracranial pressure was monitored through an indwelling ventricular catheter attached to a pressure transducer. The blood pressure was recorded through an intraarterial catheter placed in the dorsalis pedis artery. Brain blood flow was studied with Headtome SET-011 (manufactured by Shimazu Co., Ltd.). For this flow measurement study, an intravenous injection of Xenon-133 of about 30 mCi was given via an antecubital vein. The position of the slice for the SPECT was selected so as to obtain information not only from the cerebral hemisphere but also from the brain stem : a cross section 25 deg over the orbito-meatal line, passing through the inferior aspect of the frontal horn, the basal ganglia, the lower recessus of the third ventricle and the brain stem. The results indicated that, in the cerebral hemisphere, plateau waves were accompanied by a decrease in blood flow, whereas, in the brain stem, the blood flow showed little change during plateau waves as compared with the interval phase between two plateau waves. These observations may explain why there is no rise in the blood pressure and why patients are often alert during plateau waves. (author)
Single-pass BPM system of the Photon Factory storage ring.
Honda, T; Katoh, M; Mitsuhashi, T; Ueda, A; Tadano, M; Kobayashi, Y
1998-05-01
At the 2.5 GeV ring of the Photon Factory, a single-pass beam-position monitor (BPM) system is being prepared for the storage ring and the beam transport line. In the storage ring, the injected beam position during the first several turns can be measured with a single injection pulse. The BPM system has an adequate performance, useful for the commissioning of the new low-emittance lattice. Several stripline BPMs are being installed in the beam transport line. The continuous monitoring of the orbit in the beam transport line will be useful for the stabilization of the injection energy as well as the injection beam orbit.
Impact of carbon cost on wholesale electricity price: A note on price pass-through issues
Energy Technology Data Exchange (ETDEWEB)
Kim, Wook [Korea Southern Power Co., 167, Samsung-dong, Gangnam-gu, Seoul 135-791 (Korea); Chattopadhyay, Deb [Saha International, Level 26, 385 Bourke Street, Melbourne, VIC 3000 (Australia); Park, Jong-bae [Electrical Engineering Department, Konkuk University, 1 Hwayang-dong, Kwanggin-gu, Seoul 143-701 (Korea)
2010-08-15
Carbon costs - either in the form of a carbon tax or through permit prices in an emissions trading scheme - would ultimately be reflected in higher electricity prices. Carbon cost ''pass-through'' is critical to the survival of existing coal generation assets and has been discussed widely as a measure of business impact in the electricity industry. This paper sets out in a structured way the factors that determine price pass-through and why this may differ greatly across different systems. Although the basic concept of price pass-through is simple, a clear understanding of the underlying factors is critical to developing insights on how carbon cost would impact on existing coal generation businesses. It is shown that pass-through can vary drastically if the underlying dispatch potential of generators varies significantly across alternative emissions reduction scenarios. It can also vary depending on the availability of competing cleaner forms of generation. Pass-through as a measure of business performance is, therefore, hard to generalize across different circumstances and should be interpreted carefully. (author)
The use of air flow through water for water evaporation
International Nuclear Information System (INIS)
Lashin, A.A.
1996-01-01
In water desalination system the productivity rate is improved by increasing the rate of eater evaporation either by heating the water or by forcing air to carry more vapor before condensation. This paper describe an experimental investigation into the effect of forcing the air to flow through a hot water contained in a closed tank through a perforated end of inlet tube. When the air bubbles pass through the water, it increases the rate of vaporization. The effect of some operating parameters are investigated and the results are presented and discussed. 6 figs
Effect of pH on the dissolution kinetics of zero-valent iron in the presence of EDDHA and EDTA
International Nuclear Information System (INIS)
Lodge, Alexander M.; Pierce, Eric M.; Wellman, Dawn M.; Rodriguez, Elsa A.
2007-01-01
The effect of environmental factors (e.g., pH, solution composition, and temperature) that affect the longevity of Fe(0) barriers in the subsurface are difficult to quantify independently from changes that occur to the passivating layer. Therefore, to quantify the rate of Fe(0) dissolution under conditions which maintain the pO2 at a relatively constant level and minimize the formation of a passivating layer on the metal surface, a series of experiments have been conducted with the single-pass flow-through (SPFT) apparatus. These experiments were conducted over the pH range from 7.0 to 12.0 at 90 C in the presence of 5 mM EDDHA or 5 mM EDTA. The organic acids, EDDHA and EDTA, helped to maintain the aqueous Fe concentration below saturation with respect to Fe-bearing alteration phases and minimize the formation of a partially oxidized surface film. Results suggest the corrosion of Fe(0) is relatively insensitive to pH and the forward or maximum dissolution rate is 3 to 4 orders of magnitude higher than when a passive film and corrosion products are present
Peters, M. A. D.; van Drooge, A. M.; Wolkerstorfer, A.; van Gemert, M. J. C.; van der Veen, J. P. W.; Bos, J. D.; Beek, J. F.
2012-01-01
Background Pulsed dye laser (PDL) is the first choice for treatment of port wine stains (PWS). However, outcome is highly variable and only a few patients achieve complete clearance. The objective of the study was to compare efficacy and safety of single pass PDL with double pass PDL at a 6 minute
Interest Rate Pass-through in Sri Lanka
Amarasekara, Chandranath
2005-01-01
The Central Bank of Sri Lanka has increasingly been relying on interest rates as the instrument for conducting monetary policy. Changes to the key monetary policy variables, the Repo and the Reverse Repo rates, are initially expected to be reflected in the OMO rates and the call money market rates, before being passedthrough to commercial bank retail interest rates. It is important to obtain a good understanding of the speed and magnitude of the interest rate pass-through to make timely monet...
DEFF Research Database (Denmark)
Sigurdsson, Haftor Örn; Kær, Søren Knudsen
2011-01-01
Numerical and experimental study is performed to evaluate the reactant by-pass flow in a catalytic plate reactor with a coated wire mesh catalyst for steam reforming of methane for hydrogen generation. By-pass of unconverted methane is evaluated under different wire mesh catalyst width to reactor...
Single Pass Collider Memo: Gradient Perturbations of the SLC arc
Energy Technology Data Exchange (ETDEWEB)
Weng, W.T.; Sands, M.; /SLAC
2016-12-16
As the beam passes through the arcs, the gradient it encounters at each magnet differs from the design value. This deviation may be in part random and in part systematic. In this note we make estimates of the effects to be expected from both kinds of errors.
Model for Estimation of Thermal History Produced by a Single Pass Underwater Wet Weld
National Research Council Canada - National Science Library
Dill, Jay
1997-01-01
Thermal history calculations for single pass underwater wet weldments were made by solving the appropriate beat transfer equations using the three-dimensional Crank-Nicholson finite difference method...
International Nuclear Information System (INIS)
Feburie, V.; Giot, M.; Granger, S.; Seynhaeve, J.M.
1992-06-01
The leaks through steam-generator cracks are the subject of a research carried out in cooperation between EDF and UCL. A software called ECREVISSE to predict the mass flow rate has been developed and has been successfully validated. The purpose of the paper is to present the mathematical model used in ECREVISSE as well as some comparison between the results and the presently available data. The model takes into account the persistence of some metastable liquid in the crack and the special flow pattern which appears in such particular geometry. Although the model involves the use of several correlations (friction, heat transfer), no adjustment of parameters against the data has been needed, neither in the single-phase part of the flow, or in the two-phase part. (authors). 8 figs., 1 tab., 20 refs
Resolution of through tubing fluid flow and behind casing fluid flow in multiple completion wells
International Nuclear Information System (INIS)
Arnold, D.M.
1977-01-01
A method is provided for resolving undesired fluid flow in cement channels behind casing in one producing zone of a multi zone completion well operating on gas lift from the fluid flow from lower producing zones in the same well which is contained in production tubing passing through the producing zone being investigated. Gamma rays which are characteristic of the decay of the unstable isotope nitrogen 16 produced by activation of elemental oxygen nuclei comprising the molecular structure of both the tubing fluid flow and the undesired fluid flow are detected in at least two energy bonds at two longitudinally spaced detectors in a well borehole. By appropriately combining the four count rate signals so producing according to predetermined relationships the two fluid flow components in the same direction may be uniquely distinguished on the basis of their differing distances from the gamma ray detectors. 9 claims, 17 figures
A calculation technique of passing of a powerful relativistic beam through substance
International Nuclear Information System (INIS)
Pobitko, A.I.; Sal'nikov, L.I.; Sukhovitskij, E.Sh.
1995-01-01
The calculation algorithm of passing powerful relativistic beam through substance is developed. Algorithm of calculation is separated on the following problems: 1) a trial charge movement in electromagnetic field of the cylindrical geometry; 2) a computing of own electromagnetic field arising at movement of a particle heavy-current beam in a target; 3) accounting of an interaction of a beam with target atoms; 4) accounting of change of the target properties in a time; 5) geometry and construction of an iterative procedure of calculation. The calculation of passing heavy-current beams of charged particles for transient case is carried out by Monte Carlo method. A conclusion of equations of movement trial charge and technique of calculation own electromagnetic field of the powerful relativistic beam at passing through substance are resulted. 6 refs
Wibowo, Buddi; Lazuardi, Eduardo
2016-01-01
Empirical Evidence of Monetary Policy Transmission Mechanism: Indonesia Banking Sector Interest Rate Pass-throughRobust measurement of interest rates speed of adjustment to monetary policy changes is very important to obtain acomprehensive understanding on the monetary transmission process and the eectiveness of monetary policy. The speed of adjustment are determined by number of frictions that interfere with the transmission of monetary policy.We measure Indonesia interest rate pass-through ...
Flow-through biological conversion of lignocellulosic biomass
Herring, Christopher D.; Liu, Chaogang; Bardsley, John
2014-07-01
The present invention is directed to a process for biologically converting carbohydrates from lignocellulosic biomass comprising the steps of: suspending lignocellulosic biomass in a flow-through reactor, passing a reaction solution into the reactor, wherein the solution is absorbed into the biomass substrate and at least a portion of the solution migrates through said biomass substrate to a liquid reservoir, recirculating the reaction solution in the liquid reservoir at least once to be absorbed into and migrate through the biomass substrate again. The biological converting of the may involve hydrolyzing cellulose, hemicellulose, or a combination thereof to form oligosaccharides, monomelic sugars, or a combination thereof; fermenting oligosaccharides, monomelic sugars, or a combination thereof to produce ethanol, or a combination thereof. The process can further comprise removing the reaction solution and processing the solution to separate the ethanol produced from non-fermented solids.
Shah, Ajay; Darr, Matthew J; Dalluge, Dustin; Medic, Dorde; Webster, Keith; Brown, Robert C
2012-12-01
Short harvest window of corn (Zea mays) stover necessitates its storage before utilization; however, there is not enough work towards exploring the fast pyrolysis behavior of stored biomass. This study investigated the yields and the physicochemical properties (proximate and ultimate analyses, higher heating values and acidity) of the fast pyrolysis products obtained from single-pass stover and cobs stored either inside a metal building or anaerobically within plastic wraps. Biomass samples were pyrolyzed in a 183 cm long and 2.1cm inner diameter free-fall fast pyrolysis reactor. Yields of bio-oil, biochar and non-condensable gases from different biomass samples were in the ranges of 45-55, 25-37 and 11-17 wt.%, respectively, with the highest bio-oil yield from the ensiled single-pass stover. Bio-oils generated from ensiled single-pass cobs and ensiled single-pass stover were, respectively, the most and the least acidic with the modified acid numbers of 95.0 and 65.2 mg g(-1), respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Petenyi, V.; Klucarova, K.; Remis, J.
2003-01-01
The in core instrumentation of the WWER-440 reactors consists of the thermocouple system and the system of self powered detectors (SPD). The thermocouple systems are positioned about 50 cm above the fuel bundle upper flow-mixing grid. The usual assumption is that, the coolant is well mixed in the Tc location, i.e. the temperature is constant through the flow cross-section area. The present evaluations by using the FLUENT 5.5.14 code reveal that, this assumption is not fulfilled. There exists a temperature profile that depends on fuel assembly geometry and on inner power profile of the fuel assembly. The paper presents the estimation of this effect and its influence on the core power distribution and the core by-pass flow determination. Comparison with measurements in Mochovce NPP will also be a part of this presentation (Authors)
Interpretation of surface-water circulation, Aransas Pass, Texas, using Landsat imagery
Finley, R. J.; Baumgardner, R. W., Jr.
1980-01-01
The development of plumes of turbid surface water in the vicinity of Aransas Pass, Texas has been analyzed using Landsat imagery. The shape and extent of plumes present in the Gulf of Mexico is dependent on the wind regime and astronomical tide prior to and at the time of satellite overpass. The best developed plumes are evident when brisk northerly winds resuspend bay-bottom muds and flow through Aransas Pass is increased by wind stress. Seaward diversion of nearshore waters by the inlet jetties was also observed. A knowledge of surface-water circulation through Aransas Pass under various wind conditions is potentially valuable for monitoring suspended and surface pollutants
International Nuclear Information System (INIS)
Guo, Ruipeng; Tao, Zhengsu
2010-01-01
The optical characteristics of a laser beam passing through a fluid parallel layer are examined through a series of experimental tests in this project. The experimental apparatus consists of a bare surface quality measurement system and a fluid-supporting system. In the case of laser beam propagation through the static fluid layer, a modified Beckmann–Kirchhoff scattering model has been developed. Based on this model, the results of the surface quality in-process optical measurement can be amended. By extracting a ratio parameter from the image of the scattered light pattern to estimate surface roughness, the modified model can be verified quantitatively in the experimental system. As far as laser beam propagation through the flowing fluid layer is concerned, the deflection of the laser beam caused by fluid flow is small. The experiments are conducted to investigate the characteristics, and the results show that the resulting measurement error for surface quality optical measurement is in an acceptable range
Fluid mechanics relevant to flow through pretreatment of cellulosic biomass.
Archambault-Léger, Véronique; Lynd, Lee R
2014-04-01
The present study investigates fluid mechanical properties of cellulosic feedstocks relevant to flow through (FT) pretreatment for biological conversion of cellulosic biomass. The results inform identifying conditions for which FT pretreatment can be implemented in a practical context. Measurements of pressure drop across packed beds, viscous compaction and water absorption are reported for milled and not milled sugarcane bagasse, switchgrass and poplar, and important factors impacting viscous flow are deduced. Using biomass knife-milled to pass through a 2mm sieve, the observed pressure drop was highest for bagasse, intermediate for switchgrass and lowest for poplar. The highest pressure drop was associated with the presence of more fine particles, greater viscous compaction and the degree of water absorption. Using bagasse without particle size reduction, the instability of the reactor during pretreatment above 140kg/m(3) sets an upper bound on the allowable concentration for continuous stable flow. Copyright © 2014. Published by Elsevier Ltd.
Hydrodynamics of single- and two-phase flow in inclined rod arrays
International Nuclear Information System (INIS)
Todreas, N.E.
1984-01-01
Required inputs for thermal-hydraulic codes are constitutive relations for fluid-solid flow resistance, in single-phase flow, and interfacial momentum exchange (relative phase motion), in two-phase flow. An inclined rod array air-water experiment was constructed to study the hydrodynamics of multidimensional porous medium flow in rod arrays. Velocities, pressures, bubble distributions, and void fractions were measured in inline and rotational square rod arrays of P/d = 1.5, at 0, 30, 45, and 90 degree inclinations to the vertical flow direction. Constitutive models for single-phase flow resistance are reviewed, new comprehensive models developed, and an assessment with previously published and new data made. The principle of superimposing one-dimensional correlations proves successful for turbulent single-phase inclined flow. For bubbly two-phase yawed flow through incline rod arrays a new flow separation phenomena was observed and modeled. Bubbles of diameters significantly smaller than the rod diameter travel along the rod axis, while larger diameter bubbles move through the rod array gaps. The outcome is a flow separation not predictable with current interfacial momentum exchange models. This phenomenon was not observed in rotated square rod arrays. Current interfacial momentum exchange models were confirmed for this rod arrangement. Models for the two phase flow resistance multiplier for cross flow were reviewed and compared with data from cross and yawed flow rod arrays. Both drag and lift components of the multiplier were well predicted by the homogenous model. Other models reviewed overpredicted the data by a factor of two
Pressurized water reactor flow arrangement
International Nuclear Information System (INIS)
Gibbons, J.F.; Knapp, R.W.
1980-01-01
A flow path is provided for cooling the control rods of a pressurized water reactor. According to this scheme, a small amount of cooling water enters the control rod guide tubes from the top and passes downwards through the tubes before rejoining the main coolant flow and passing through the reactor core. (LL)
Just passing through --- high Hg deposition to Puerto Rico forest moves quickly off the landscape
Shanley, J. B.; Willenbring, J. K.; Kaste, J. M.; Occhi, M.; McDowell, W. H.
2012-12-01
Atmospheric mercury (Hg) in wet deposition at the Luquillo Experimental Forest in northeastern Puerto Rico, averages 28 μg m-2 yr-1, higher than any site in the USA Mercury Deposition Network. Despite the high deposition, Hg content of soils, vegetation, and biota are below global averages. The low Hg content of watershed surfaces, coupled with exceptionally high stream total Hg flux, suggest that most of the Hg passes through the watershed with minimal retention. We assessed Hg dynamics in two adjacent watersheds, Rio Icacos underlain by quartz diorite, and Rio Mameyes underlain by volcaniclastic rocks. At both sites, high-flow Hg concentrations approached 100 ng L-1, dominated by particulate Hg. In order to assess the apparent pass-through nature of Hg in this tropical forest, we measured 7Be and 10Be isotopes from natural, cosmogenic fallout adsorbed on stream suspended particles to constrain the Hg age /residence time and source (atmospheric vs. geogenic or legacy Hg from 19th century gold mining). Ubiquitous 7Be (half-life 53 days) and relatively high 7Be/10Be ratios on suspended particles suggest that stream Hg was dominated by erosion from exposed surfaces, supporting a short residence time. The low watershed retention of the high Hg throughput limits adverse biological effects in this tropical ecosystem.
Energy Technology Data Exchange (ETDEWEB)
Semchishen, A V; Seminogov, V N; Semchishen, V A [Institute of Laser and Information Technologies, Russian Academy of Sciences, Troitsk, Moscow Region (Russian Federation)
2012-04-30
Forward scattering of light passing through large-scale irregularities of the interface between two media having different refractive indices is considered. An analytical expression for the ratio of intensities of directional and diffusion components of scattered light in the far-field zone is derived. It is theoretically shown that the critical depth of possible interface relief irregularities, starting from which the intensity of the diffuse component in the passing light flow becomes comparable with the directional light component, responsible for the image formation on the eye retina, is 3 - 4 {mu}m, with the increase in the refractive index in the postoperational zone taken into account. These profile depth values agree with the experimentally measured ones and may affect the contrast sensitivity of vision.
International Nuclear Information System (INIS)
Semchishen, A V; Seminogov, V N; Semchishen, V A
2012-01-01
Forward scattering of light passing through large-scale irregularities of the interface between two media having different refractive indices is considered. An analytical expression for the ratio of intensities of directional and diffusion components of scattered light in the far-field zone is derived. It is theoretically shown that the critical depth of possible interface relief irregularities, starting from which the intensity of the diffuse component in the passing light flow becomes comparable with the directional light component, responsible for the image formation on the eye retina, is 3 - 4 μm, with the increase in the refractive index in the postoperational zone taken into account. These profile depth values agree with the experimentally measured ones and may affect the contrast sensitivity of vision.
CO2 cost pass-through and windfall profits in the power sector
International Nuclear Information System (INIS)
Sijm, Jos; Neuhoff, Karsten; Yihsu Chen
2006-01-01
In order to cover their CO 2 emissions, power companies receive most of the required EU ETS allowances for free. In line with economic theory, these companies pass on the costs of these allowances in the price of electricity. This article analyses the implications of the EU ETS for the power sector, notably the impact of free allocation of CO 2 emission allowances on the price of electricity and the profitability of power generation. As well as some theoretical reflections, the article presents empirical and model estimates of CO 2 cost pass-through for Germany and The Netherlands, indicating that pass-through rates vary between 60 and 100% of CO 2 costs, depending on the carbon intensity of the marginal production unit and various other market- or technology-specific factors. As a result, power companies realize substantial windfall profits, as indicated by the empirical and model estimates presented in the article. (Author)
International Nuclear Information System (INIS)
Mukhopadhyay, Swati; Arif, M. Golam; Pk M Wazed Ali
2013-01-01
The aim of this article is to present the effects of transpiration on the unsteady two-dimensional boundary layer flow of non-Newtonian fluid passing through a stretching sheet in the presence of a first order constructive/destructive chemical reaction. The upper-convected Maxwell (UCM) model is used here to characterize the non-Newtonian behavior of the fluid. Using similarity solutions, the governing nonlinear partial differential equations are transformed into ordinary ones and are then solved numerically by the shooting method. The flow fields and mass transfer are significantly influenced by the governing parameters. The fluid velocity initially decreases as the unsteadiness parameter increases and the concentration decreases significantly due to the increase in the unsteadiness. The effect of increasing values of transpiration (suction) and the Maxwell parameter is to suppress the velocity field; however, the concentration is enhanced as transpiration (suction) and the Maxwell parameter increase. Also, it is found that the fluid velocity decreases as the magnetic parameter increases; however, the concentration increases in this case. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Single-Sided Natural Ventilation through a Velux Roof Window
DEFF Research Database (Denmark)
Li, Zhigang; Nielsen, Peter Vilhelm; Fransson, J.
2004-01-01
This paper investigates the single-sided natural ventilation through a VELUX centre pivot roof window under natural weather conditions. The aim of the investigation is to develop an empirical formulation for air flow rate through a roof window based on CFD and tracer gas decay measurement methods...
Long life neutron generator target using deuterium pass-through structure
Alger, D. L.
1974-01-01
Target structure permits all deuterons, except the one-in-a-million that interacts with tritium atom to produce a neutron, to pass completely through target structure and be returned to vacuum system. Since tritium atoms are not displaced as in conventional targets, tritium population will remain unchanged while under deuteron bombardment.
Stopping dynamics of ions passing through correlated honeycomb clusters
Balzer, Karsten; Schlünzen, Niclas; Bonitz, Michael
2016-12-01
A combined nonequilibrium Green functions-Ehrenfest dynamics approach is developed that allows for a time-dependent study of the energy loss of a charged particle penetrating a strongly correlated system at zero and finite temperatures. Numerical results are presented for finite inhomogeneous two-dimensional Fermi-Hubbard models, where the many-electron dynamics in the target are treated fully quantum mechanically and the motion of the projectile is treated classically. The simulations are based on the solution of the two-time Dyson (Keldysh-Kadanoff-Baym) equations using the second-order Born, third-order, and T -matrix approximations of the self-energy. As application, we consider protons and helium nuclei with a kinetic energy between 1 and 500 keV/u passing through planar fragments of the two-dimensional honeycomb lattice and, in particular, examine the influence of electron-electron correlations on the energy exchange between projectile and electron system. We investigate the time dependence of the projectile's kinetic energy (stopping power), the electron density, the double occupancy, and the photoemission spectrum. Finally, we show that, for a suitable choice of the Hubbard model parameters, the results for the stopping power are in fair agreement with ab initio simulations for particle irradiation of single-layer graphene.
Two-phase flow through small branches in a horizontal pipe with stratified flow
International Nuclear Information System (INIS)
Smoglie, C.
1984-12-01
This report presents the description and results of experiments designed to determine the mass flow rate and quality through a small break at the bottom, the top or the side of a main pipe with stratified gas-liquid flow. If the interface level is far below (above) the branch, only single-phase gas (liquid) flow enters the branch. For smaller distances the interface is locally deformed because of the pressure decrease due to the fluid acceleration near the branch inlet (Bernoulli effect) and liquid (gas) can be entrained. This report contains photographs illustrating the flow phenomena as well as a general correlation to determine the beginning of entrainment. Results are presented on the branch mass flow rate and quality as a function of a normalized distance between the interface and the branch inlet. A model was developed which enables to predict the branch quality and mass flux. Results from air-water flow through horizontal branches, were extrapolated for steam water flow at high pressure with critical branch mass flux. (orig./HP) [de
Liu, Jinfeng; You, Yong; Zhang, Guangze; Wang, Dong; Chen, Jiangang; Chen, Huayong
2017-04-01
The Ranwu-Tongmai section of the Sichuan-Tibet Railway passes through the Palongzangbu River basin which locates in the southeast Qinghai-Tibetan Plateau. Due to widely distributed maritime glacier in this area, the huge glacier debris flows are very developed. Consequently, the disastrous glacier debris flows with huge scale (106-108 m3 for one debris flow event) and damage become one of the key influencing factors for the route alignment of the Sichuan-Tibet Railway. The research on disaster characteristics and mitigation measures of huge glacial debris flows in the study area were conducted by the remote sensing interpretation, field investigation, parameter calculation and numerical simulation. Firstly, the distribution of the glaciers, glacier lakes and glacier debris flows were identified and classified; and the disaster characteristics for the huge glacier debris flow were analyzed and summarized. Secondly, the dynamic parameters including the flood peak discharge, debris flow peak discharge, velocity, total volume of a single debris flow event were calculated. Based on the disaster characteristics and the spatial relation with the railway, some mitigation principles and measures were proposed. Finally, the Guxiang Gully, where a huge glacier debris flow with 2*108m3 in volume occurred in 1953, was selected as a typical case to analyze its disaster characteristics and mitigation measures. The interpretation results show that the glacier area is about 970 km2 which accounts for 19% of the total study area. 130 glacier lakes and 102 glacier debris flows were identified and classified. The Sichuan-Tibet Railway passes through 43 glacier debris flows in the study area. The specific disaster characteristics were analyzed and corresponding mitigation measures were proposed for the route selection of the railway. For the Guxiang Gully, a numerical simulation to simulate the deposition condition at the alluvial fan was conducted. the simulation results show that the
Prediction of critical flow rates through power-operated relief valves
International Nuclear Information System (INIS)
Abdollahian, D.; Singh, A.
1983-01-01
Existing single-phase and two-phase critical flow models are used to predict the flow rates through the power-operated relief valves tested in the EPRI Safety and Relief Valve test program. For liquid upstream conditions, Homogeneous Equilibrium Model, Moody, Henry-Fauske and Burnell two-phase critical flow models are used for comparison with data. Under steam upstream conditions, the flow rates are predicted either by the single-phase isentropic equations or the Homogeneous Equilibrium Model, depending on the thermodynamic condition of the fluid at the choking plane. The results of the comparisons are used to specify discharge coefficients for different valves under steam and liquid upstream conditions and evaluate the existing approximate critical flow relations for a wide range of subcooled water and steam conditions
45 CFR 303.52 - Pass-through of incentives to political subdivisions.
2010-10-01
... 45 Public Welfare 2 2010-10-01 2010-10-01 false Pass-through of incentives to political subdivisions. 303.52 Section 303.52 Public Welfare Regulations Relating to Public Welfare OFFICE OF CHILD SUPPORT ENFORCEMENT (CHILD SUPPORT ENFORCEMENT PROGRAM), ADMINISTRATION FOR CHILDREN AND FAMILIES...
By-pass flows and temperature distribution in a hot gas duct internally insulated by carbon stone
International Nuclear Information System (INIS)
Konuk, A.A.
1979-01-01
A mathematical model has been developed to calculate by-pass flows and temperature distribution in a hot gas duct internally insulated by carbon stone rings. The equations of conservation of mass and momentum are solved for a piping system to obtain axial and radial by-pass velocities. The energy equation is solved next by a marching method to obtain the radial temperature distribution along the duct. The results, although qualitative due to simplifications in the model, are useful to study the effects of duct geometry on its performance. (Author) [pt
Multi-pass spectroscopic ellipsometry
International Nuclear Information System (INIS)
Stehle, Jean-Louis; Samartzis, Peter C.; Stamataki, Katerina; Piel, Jean-Philippe; Katsoprinakis, George E.; Papadakis, Vassilis; Schimowski, Xavier; Rakitzis, T. Peter; Loppinet, Benoit
2014-01-01
Spectroscopic ellipsometry is an established technique, particularly useful for thickness measurements of thin films. It measures polarization rotation after a single reflection of a beam of light on the measured substrate at a given incidence angle. In this paper, we report the development of multi-pass spectroscopic ellipsometry where the light beam reflects multiple times on the sample. We have investigated both theoretically and experimentally the effect of sample reflectivity, number of reflections (passes), angles of incidence and detector dynamic range on ellipsometric observables tanΨ and cosΔ. The multiple pass approach provides increased sensitivity to small changes in Ψ and Δ, opening the way for single measurement determination of optical thickness T, refractive index n and absorption coefficient k of thin films, a significant improvement over the existing techniques. Based on our results, we discuss the strengths, the weaknesses and possible applications of this technique. - Highlights: • We present multi-pass spectroscopic ellipsometry (MPSE), a multi-pass approach to ellipsometry. • Different detectors, samples, angles of incidence and number of passes were tested. • N passes improve polarization ratio sensitivity to the power of N. • N reflections improve phase shift sensitivity by a factor of N. • MPSE can significantly improve thickness measurements in thin films
Kim, Ji-Woong; Phuong, Nguyen Lu; Aramaki, Shin-Ichiro; Ito, Kazuhide
2018-05-01
Studies concerning inhalation toxicology and respiratory drug-delivery systems require biological testing involving experiments performed on animals. Particle image velocimetry (PIV) is an effective in vitro technique that reveals detailed inhalation flow patterns, thereby assisting analyses of inhalation exposure to various substances. A realistic model of a rhesus-monkey upper airway was developed to investigate flow patterns in its oral and nasal cavities through PIV experiments performed under steady-state constant inhalation conditions at various flow rates-4, 10, and 20 L/min. Flow rate of the fluid passing through the inlet into the trachea was measured to obtain characteristic flow mechanisms, and flow phenomena in the model were confirmed via characterized flow fields. It was observed that increase in flow rate leads to constant velocity profiles in upper and lower trachea regions. It is expected that the results of this study would contribute to future validation of studies aimed at developing in silico models, especially those involving computational fluid dynamic (CFD) analysis. Copyright © 2018 Elsevier B.V. All rights reserved.
Wei, Cai-Jie; Wu, Wei-Zhong
2018-09-01
Two kinds of hybrid two-step multi-soil-layering (MSL) systems loaded with different filter medias (zeolite-ceramsite MSL-1 and ceramsite-red clay MSL-2) were set-up for the low-(C/N)-ratio polluted river water treatment. A long-term pollutant removal performance of these two kinds of MSL systems was evaluated for 214 days. By-pass was employed in MSL systems to evaluate its effect on nitrogen removal enhancement. Zeolite-ceramsite single-pass MSL-1 system owns outstanding ammonia removal capability (24 g NH 4 + -Nm -2 d -1 ), 3 times higher than MSL-2 without zeolite under low aeration rate condition (0.8 × 10 4 L m -2 .h -1 ). Aeration rate up to 1.6 × 10 4 L m -2 .h -1 well satisfied the requirement of complete nitrification in first unit of both two MSLs. However, weak denitrification in second unit was commonly observed. By-pass of 50% influent into second unit can improve about 20% TN removal rate for both MSL-1 and MSL-2. Complete nitrification and denitrification was achieved in by-pass MSL systems after addition of carbon source with the resulting C/N ratio up to 2.5. The characters of biofilms distributed in different sections inside MSL-1 system well illustrated the nitrogen removal mechanism inside MSL systems. Two kinds of MSLs are both promising as an appealing nitrifying biofilm reactor. Recirculation can be considered further for by-pass MSL-2 system to ensure a complete ammonia removal. Copyright © 2018 Elsevier Ltd. All rights reserved.
Simultaneous ultrasound and photoacoustics based flow cytometry
Gnyawali, Vaskar; Strohm, Eric M.; Tsai, Scott S. H.; Kolios, Michael C.
2018-04-01
We have developed a flow cytometer based on simultaneous detection of ultrasound and photoacoustic waves from individual particles/cells flowing in a microfluidic channel. Our polydimethylsiloxane (PDMS) based hydrodynamic 3-dimensional (3D) flow-focusing microfluidic device contains a cross-junction channel, a micro-needle (ID 100 μm and OD 200 μm) insert, and a 3D printed frame to hold and align a high frequency (center frequency 375 MHz) ultrasound transducer. The focused flow passes through a narrow focal zone with lateral and axial focal lengths of 6-8 μm and 15-20 μm, respectively. Both the lateral and axial alignments are achieved by screwing the transducer to the frame onto the PDMS device. Individual particles pass through an interrogation zone in the microfluidic channel with a collinearly aligned ultrasound transducer and a focused 532 nm wavelength laser beam. The particles are simultaneously insonified by high-frequency ultrasound and irradiated by a laser beam. The ultrasound backscatter and laser generated photoacoustic waves are detected for each passing particle. The backscattered ultrasound and photoacoustic signal are strongly dependent on the size, morphology, mechanical properties, and material properties of the flowing particles; these parameters can be extracted by analyzing unique features in the power spectrum of the signals. Frequencies less than 100 MHz do not have these unique spectral signatures. We show that we can reliably distinguish between different particles in a sample using the acoustic-based flow cytometer. This technique, when extended to biomedical applications, allows us to rapidly analyze the spectral signatures from individual single cells of a large cell population, with applications towards label-free detection and characterization of healthy and diseased cells.
Kawakami, Shuji; Hasegawa, Takuya; Imachi, Hiroyuki; Yamaguchi, Takashi; Harada, Hideki; Ohashi, Akiyoshi; Kubota, Kengo
2012-02-01
In situ detection of functional genes with single-cell resolution is currently of interest to microbiologists. Here, we developed a two-pass tyramide signal amplification (TSA)-fluorescence in situ hybridization (FISH) protocol with PCR-derived polynucleotide probes for the detection of single-copy genes in prokaryotic cells. The mcrA gene and the apsA gene in methanogens and sulfate-reducing bacteria, respectively, were targeted. The protocol showed bright fluorescence with a good signal-to-noise ratio and achieved a high efficiency of detection (>98%). The discrimination threshold was approximately 82-89% sequence identity. Microorganisms possessing the mcrA or apsA gene in anaerobic sludge samples were successfully detected by two-pass TSA-FISH with polynucleotide probes. The developed protocol is useful for identifying single microbial cells based on functional gene sequences. Copyright © 2011 Elsevier B.V. All rights reserved.
Martins Bitans
2004-01-01
The paper examines the exchange rate pass-through in a set of 13 East European countries during the period of 1993–2003. The pass-through estimates are derived from a recursive VAR model in first differences, and the impact of exchange rate changes on both producer and consumer prices is studied. The estimates obtained for two sub-sample periods generally show an incomplete pass-through over a two-year horizon. In addition, the results imply a considerable cross-country variation and suggest ...
Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device
International Nuclear Information System (INIS)
Papell, S.S.; Nyland, T.W.; Saiyed, N.H.
1992-07-01
Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomson devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1-X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band. 3 refs
Two-phase flow through small branches in a horizontal pipe with stratified flow
International Nuclear Information System (INIS)
Smoglie, C.
1985-02-01
In the field of reactor safety the occurrence of a small break in a horizontal primary coolant pipe is of great importance. This report presents the description and results of experiments designed to determine the mass flow rate and quality through a small break at the bottom, the top or the side of a main pipe with stratified gas-liquid flow. If the interface level is far below (above) the branch, only single-phase gas (liquid) flow enters the branch. For smaller distances the interface is locally deformed because of the pressure decrease due to the fluid acceleration near the branch inlet (Bernoulli effect) and liquid (gas) can be entrained. This report contains photographs illustrating the flow phenomena as well as a general correlation to determine the beginning of entrainment. Results are presented on the branch mass flow rate and quality as a function of a normalized distance between the interface and the branch inlet. A model was developed which enables to predict the branch quality and mass flux. Results from air-water flow through horizontal branches, were extrapolated for steam water flow at high pressure with critical branch mass flux. (orig./HS) [de
Hoque, Sazid Zamal; Anand, D. Vijay; Patnaik, B. S. V.
2017-11-01
The state of the red blood cell (either healthy or infected RBC) will influence its deformation dynamics. Since the pathological condition related to RBC, primarily originates from a single cell infection, therefore, it is important to relate the deformation dynamics to the mechanical properties (such as, bending rigidity and membrane elasticity). In the present study, numerical simulation of a healthy and malaria infected RBC in a constricted channel is analyzed. The flow simulations are carried out using finite sized dissipative particle dynamics (FDPD) method in conjunction with a discrete model that represents the membrane of the RBC. The numerical equivalent of optical tweezers test is validated against the experimental studies. Two different types of constrictions, viz., a converging-diverging type tapered channel and a stenosed microchannel are considered for the simulation. The effect of degree of constriction and the flow rate effect on the RBC is investigated. It was observed that, as the flow rate decreases, the infected RBC completely blocks the micro vessel. The transit time for infected cell drastically increases compared to healthy RBC. Our simulations indicate that, there is a critical flow rate below which infected RBC cannot pass through the micro capillary.
Stream capture to form Red Pass, northern Soda Mountains, California
Miller, David; Mahan, Shannon
2014-01-01
Red Pass, a narrow cut through the Soda Mountains important for prehistoric and early historic travelers, is quite young geologically. Its history of downcutting to capture streams west of the Soda Mountains, thereby draining much of eastern Fort Irwin, is told by the contrast in alluvial fan sediments on either side of the pass. Old alluvial fan deposits (>500 ka) were shed westward off an intact ridge of the Soda Mountains but by middle Pleistocene time, intermediate-age alluvial fan deposits (~100 ka) were laid down by streams flowing east through the pass into Silurian Valley. The pass was probably formed by stream capture driven by high levels of groundwater on the west side. This is evidenced by widespread wetland deposits west of the Soda Mountains. Sapping and spring discharge into Silurian Valley over millennia formed a low divide in the mountains that eventually was overtopped and incised by a stream. Lessons include the importance of groundwater levels for stream capture and the relatively youthful appearance of this ~100-200 ka feature in the slowly changing Mojave Desert landscape.
Directory of Open Access Journals (Sweden)
Arintoko Arintoko
2011-06-01
Full Text Available This study estimates the exchange rate pass-through into domestic prices in Indonesia in the two-stage approach. The study focuses on first step pass-through, i.e. ERPT into import prices and second step pass-through, i.e. into consumer prices, using cointegration and error-correction mechanism (ECM model. This research uses a Zivot-Andrews technique to test for structural breaks and Gregory-Hansen models to tests. The results show that the long run ERPT to import prices with structural breaks is relatively low compared to the results without them. The absolut error correction term values resulted from cointegration are decreased and the error-correction models need period lagged longer than one-period if the estimation included the estimated structural breaks. The main finding is that allowing for possible breaks around the crises in Indonesia, and a shift of the exchange rate management from managed to free floating in 1997 helps to restore a long run cointegration relationship estimation.
Vibrationally coupled electron transport through single-molecule junctions
Energy Technology Data Exchange (ETDEWEB)
Haertle, Rainer
2012-04-26
Single-molecule junctions are among the smallest electric circuits. They consist of a molecule that is bound to a left and a right electrode. With such a molecular nanocontact, the flow of electrical currents through a single molecule can be studied and controlled. Experiments on single-molecule junctions show that a single molecule carries electrical currents that can even be in the microampere regime. Thereby, a number of transport phenomena have been observed, such as, for example, diode- or transistor-like behavior, negative differential resistance and conductance switching. An objective of this field, which is commonly referred to as molecular electronics, is to relate these transport phenomena to the properties of the molecule in the contact. To this end, theoretical model calculations are employed, which facilitate an understanding of the underlying transport processes and mechanisms. Thereby, one has to take into account that molecules are flexible structures, which respond to a change of their charge state by a profound reorganization of their geometrical structure or may even dissociate. It is thus important to understand the interrelation between the vibrational degrees of freedom of a singlemolecule junction and the electrical current flowing through the contact. In this thesis, we investigate vibrational effects in electron transport through singlemolecule junctions. For these studies, we calculate and analyze transport characteristics of both generic and first-principles based model systems of a molecular contact. To this end, we employ a master equation and a nonequilibrium Green's function approach. Both methods are suitable to describe this nonequilibrium transport problem and treat the interactions of the tunneling electrons on the molecular bridge non-perturbatively. This is particularly important with respect to the vibrational degrees of freedom, which may strongly interact with the tunneling electrons. We show in detail that the resulting
Yamaguchi, H.; Takamori, K.; Perrier, P.; Graur, I.; Matsuda, Y.; Niimi, T.
2016-01-01
The viscous slip coefficient for helium-argon binary gas mixture is extracted from the experimental values of the mass flow rate through a microtube. The mass flow rate is measured by the constant-volume method. The viscous slip coefficient was obtained by identifying the measured mass flow rate through a microtube with the corresponding analytical expression, which is a function of the Knudsen number. The measurements were carried out in the slip flow regime where the first-order slip bounda...
Important remarks on the problem of neutrino passing through the matter
International Nuclear Information System (INIS)
Beshtoev, Kh.M.
2011-01-01
It is supposed that resonance enhancement of neutrino oscillations in the matter appears while a neutrino is passing through the matter. It is shown that Wolfenstein equation, for a neutrino passing through the matter, has a disadvantage (it does not take into account the law of momentum conservation; i.e., it is supposed that in the matter the neutrino energy changes, but its momentum does not). It leads, for example, to changing the effective mass of the neutrino by the value 0.87 · 10 -2 eV from a very small value of energy polarization of the matter caused by the neutrino, which is equal 5 · 10 -12 eV. After removing this disadvantage (i.e., taking into account that neutrino momentum also changes in matter) we have obtained a solution to this equation. In this solution a very small enhancement of neutrino oscillations in the solar matter appears due to the smallness of the energy polarization of the matter caused by the neutrino. Two possible solutions to this equation are also given for the limiting cases
Xuan, Chuang; Oda, Hirokuni
2015-11-01
The rapid accumulation of continuous paleomagnetic and rock magnetic records acquired from pass-through measurements on superconducting rock magnetometers (SRM) has greatly contributed to our understanding of the paleomagnetic field and paleo-environment. Pass-through measurements are inevitably smoothed and altered by the convolution effect of SRM sensor response, and deconvolution is needed to restore high-resolution paleomagnetic and environmental signals. Although various deconvolution algorithms have been developed, the lack of easy-to-use software has hindered the practical application of deconvolution. Here, we present standalone graphical software UDECON as a convenient tool to perform optimized deconvolution for pass-through paleomagnetic measurements using the algorithm recently developed by Oda and Xuan (Geochem Geophys Geosyst 15:3907-3924, 2014). With the preparation of a format file, UDECON can directly read pass-through paleomagnetic measurement files collected at different laboratories. After the SRM sensor response is determined and loaded to the software, optimized deconvolution can be conducted using two different approaches (i.e., "Grid search" and "Simplex method") with adjustable initial values or ranges for smoothness, corrections of sample length, and shifts in measurement position. UDECON provides a suite of tools to view conveniently and check various types of original measurement and deconvolution data. Multiple steps of measurement and/or deconvolution data can be compared simultaneously to check the consistency and to guide further deconvolution optimization. Deconvolved data together with the loaded original measurement and SRM sensor response data can be saved and reloaded for further treatment in UDECON. Users can also export the optimized deconvolution data to a text file for analysis in other software.
Directory of Open Access Journals (Sweden)
B Chaturvedi
2015-12-01
Full Text Available In this paper, a new voltage controlled first order all-pass filter is presented. The proposed circuit employs a single differential voltage dual-X second generation current conveyor (DV-DXCCII and a grounded capacitor only. The proposed all-pass filter provides both inverting and non inverting voltage-mode outputs from the same configuration simultaneously without any matching condition. Non-ideal analysis along with sensitivity analysis is also investigated. The proposed circuit has low active and passive sensitivities. As an application the proposed all-pass filter is connected in cascade to get higher order filter. The theoretical results are validated thorough PSPICE simulations using TSMC 0.18µm CMOS process parameters.
Chu V. Nguyen
2017-01-01
This study utilizes an Autoregressive Distributed Lag model to investigate the nature of crude oil futures price pass-through since 2006. The empirical results reveal a very high but incomplete short-run pass-through rate from the crude oil futures price to the gasoline futures price of 0.849298 with a corresponding negative long-run pass-through rate of -0.2440894. These empirical findings suggest that traders in the U.S. oil and gasoline futures markets overreact to fluctuations in the crud...
A facility for the experimental investigation of single substance two phase flow
International Nuclear Information System (INIS)
Maeder, P.F.; Dickinson, D.A.; Nikitopoulos, D.E.; DiPippo, R.
1985-01-01
The paper describes a research facility dedicated to single-substance two-phase flow. The working fluid is dichlorotetrafluoroethane (or refrigerant R-114), allowing both operation at manageable pressures, temperatures and flowrates, and application of results to practical situations through similarity. Operation is in the blowdown mode. The control and data acquisition systems are fully automated and computer controlled. A range of flow conditions from predominantly liquid flow to high velocity, high void fraction choked flow can be attained
Geometrical influences on multi-pass laser forming
International Nuclear Information System (INIS)
Edwardson, S P; Abed, E; Bartkowiak, K; Dearden, G; Watkins, K G
2006-01-01
Laser forming (LF) offers the industrial promise of controlled shaping of metallic and non-metallic components for prototyping, the correction of design shape or distortion and precision adjustment applications. The potential process advantages include precise incremental adjustment, flexibility of application and no mechanical 'spring-back' effect. To date there has been a considerable amount of work carried out on two-dimensional LF, using multi-pass straight line scan strategies to produce a reasonably controlled bend angle in a number of materials, including aerospace alloys. A key area, however, where there is a limited understanding, is the variation in bend angle per pass during multi-pass LF along a single irradiation track; in particular, the decrease in bend angle per pass after many irradiations for a given set of process parameters. Understanding this is essential if the process is to be fully controlled in a manufacturing environment. The research presented in this paper highlights the current theories as to why this occurs and proposes a further reason based on the geometrical effects of the component deformation, which in turn influences the process parameters per pass. This theory is confirmed through empirical analysis of the 2D LF process
Exchange Rate Pass-through and Monetary Policy in South Africa
Aron, Janine; Farrell, Greg; Muellbauer, John; Sinclair, Peter
2010-01-01
Understanding how import prices adjust to exchange rates helps anticipate inflation effects and monetary policy responses. This paper examines exchange rate passthrough to the monthly import price index in South Africa during 1980-2009. A methodological innovation allows various short-run pass-through estimates to be calculated simply without recourse to a full structural model, yet without neglecting the long-run relationships between prices or the effects of previous import price changes, a...
Heat Transfer Characteristics of the Supercritical CO2 Flowing in a Vertical Annular Channel
International Nuclear Information System (INIS)
Yoo, Tae Ho; Bae, Yoon Yeong; Kim, Hwan Yeol
2010-01-01
Heat transfer test facility, SPHINX(Supercritical Pressure Heat transfer Investigation for NeXt generation), has been operated at KAERI for an investigation of the thermal-hydraulic characteristics of supercritical CO 2 at several test sections with a different geometry. The loop uses CO 2 because it has much lower critical pressure and temperature than those of water. Experimental study of heat transfer to supercritical CO 2 in a vertical annular channel with and hydraulic diameter of 4.5 mm has been performed. CO 2 flows downward through the annular channel simulating the downward-flowing coolant in a multi-pass reactor or water rod moderator in a single pass reactor. The heat transfer characteristics in a downward flow were analyzed and compared with the upward flow test results performed previously with the same test section at KAERI
A novel concept of measuring mass flow rates using flow induced ...
Indian Academy of Sciences (India)
Measurement of mass flow rate is important for automatic control of the mass flow rate in .... mass flow rate. The details are as follows. ... Assuming a symmetry plane passing through the thickness of the plate, at the symmetry plane δu∗n,B = 0.
Soap-film flow induced by electric fields in asymmetric frames
Mollaei, S.; Nasiri, M.; Soltanmohammadi, N.; Shirsavar, R.; Ramos, A.; Amjadi, A.
2018-04-01
Net fluid flow of soap films induced by (ac or dc) electric fields in asymmetric frames is presented. Previous experiments of controllable soap film flow required the simultaneous use of an electrical current passing through the film and an external electric field or the use of nonuniform ac electric fields. Here a single voltage difference generates both the electrical current going through the film and the electric field that actuates on the charge induced on the film. The film is set into global motion due to the broken symmetry that appears by the use of asymmetric frames. If symmetric frames are used, the film flow is not steady but time dependent and irregular. Finally, we study numerically these film flows by employing the model of charge induction in ohmic liquids.
Flow through the nasal cavity of the spiny dogfish, Squalus acanthias
Timm-Davis, L. L.; Fish, F. E.
2015-12-01
The nasal cavity of spiny dogfish is a blind capsule with no internal connection to the oral cavity. Water is envisioned to flow through the cavity in a smooth, continuous flow pattern; however, this assumption is based on previous descriptions of the morphology of the olfactory cavity. No experimentation on the flow through the internal nasal cavity has been reported. Morphology of the head of the spiny dogfish ( Squalus acanthias) does not suggest a close external connection between the oral and nasal systems. However, dye visualization showed that there was flow through the nasal apparatus and from the excurrent nostril to the mouth when respiratory flows were simulated. The hydrodynamic flow through the nasal cavity was observed from flow tank experiments. The dorsum of the nasal cavity of shark heads from dead animals was exposed by dissection and a glass plate was glued over of the exposed cavity. When the head was placed in a flow, dye was observed to be drawn passively into the cavity showing a complex, three-dimensional hydrodynamic flow. Dye entered the incurrent nostril, flowed through the nasal lamellae, crossed over and under the nasal valve, and circulated around the nasal valve before exiting the excurrent nostril. When the nasal valve was removed, the dye became stagnant and back flowed out through the incurrent nostril. The single nasal valve has a hydrodynamic function that organizes a coherent flow of water through the cavity without disruption. The results suggest that the morphology of the nasal apparatus in concert with respiratory flow and ambient flows from active swimming can be used to draw water through the olfactory cavity of the shark.
Directory of Open Access Journals (Sweden)
Chun Sheng Lin
2013-03-01
Full Text Available The study of the heat transfer of solar air heaters with a new design using an absorbing plate with fins and baffles, which facilitate the recycling of flowing air, is reported. The mathematical formulation and analytical analysis for such a recyclic baffled double-pass solar air heater were developed theoretically. The performance of the device was studied experimentally as well. The theoretical predicted and experimental results were compared with another design, i.e., a downward-type single-pass solar air heater without recycle and double-pass operations reported in our previous work. Significant improvement in heat-transfer efficiency is achieved with the baffle and fin design due to the recycling heating and the extended heat transfer area. The effects of mass flow rate and recycle ratio on the heat-transfer efficiency enhancement as well as on the power consumption increment are also discussed.
Lattice gas automata simulations of flow through porous media
International Nuclear Information System (INIS)
Matsukuma, Yosuke; Abe, Yutaka; Adachi, Hiromichi; Takahashi, Ryoichi
1998-01-01
In the course of a severe accident, a debris bed may be formed from once- molten and fragmented fuel elements. In order to avoid further degradation of the reactor core, it is necessary to remove the heat from the debris bed since the debris bed still release the decay heat. So as to predict the coolability of the debris bed, it is important to precisely estimate flow patterns through complex geometry of debris bed in microscopic level. Lattice gas automata could be powerful tool to simulate such a complex geometry. As a first step of the study, fundamental numerical simulation were conducted in two dimensional systems by using the lattice gas automata method to clarify single phase flow patterns through porous media in mesoscopic level. Immiscible lattice gas model is one of the lattice gas automata method and utilized for spinodal decomposition simulation of binary fluids. This model was applied to generate the complex flow geometry simulating porous media. It was approved that the complex flow geometries were successfully generated by the present method. Flow concentration was observed in specified flow channels for lower Reynolds number. Two dimensional flow concentration was caused by the irregular flow geometry generated by the present method, since the flow selects the channels of lower friction. Two dimensional pressure distribution was observed relating to the concentrations of flow in specified channels. The simulating results of the flow through the porous media by the present method qualitatively agree with the Ergun's equation. Quantitatively, the present results approach to Ergun's equation in higher Reynolds number than 10, although concentration of the flow in a specified flow channels were observed in lower Reynolds number than 10. It can be concluded that this technique is useful is useful to simulate flow through complex geometry like porous media. (author)
Heat Transfer Characteristics of the Supercritical CO{sub 2} Flowing in a Vertical Annular Channel
Energy Technology Data Exchange (ETDEWEB)
Yoo, Tae Ho; Bae, Yoon Yeong; Kim, Hwan Yeol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2010-05-15
Heat transfer test facility, SPHINX(Supercritical Pressure Heat transfer Investigation for NeXt generation), has been operated at KAERI for an investigation of the thermal-hydraulic characteristics of supercritical CO{sub 2} at several test sections with a different geometry. The loop uses CO{sub 2} because it has much lower critical pressure and temperature than those of water. Experimental study of heat transfer to supercritical CO{sub 2} in a vertical annular channel with and hydraulic diameter of 4.5 mm has been performed. CO{sub 2} flows downward through the annular channel simulating the downward-flowing coolant in a multi-pass reactor or water rod moderator in a single pass reactor. The heat transfer characteristics in a downward flow were analyzed and compared with the upward flow test results performed previously with the same test section at KAERI
Milestone experiments for single pass UV/X-ray FELs
Ben-Zvi, Ilan
1995-04-01
In the past decade, significant advances have been made in the theory and technology of high brightness electron beams and single pass FELs. These developments facilitate the construction of practical UV and X-ray FELs and has prompted proposals to the DOE for the construction of such facilities. There are several important experiments to be performed before committing to the construction of dedicated user facilities. Two experiments are under construction in the IR, the UCLA self-amplified spontaneous emission experiment and the BNL laser seeded harmonic generation experiment. A multi-institution collaboration is being organized about a 210 MeV electron linac available at BNL and the 10 m long NISUS wiggler. This experiment will be done in the UV and will test various experimental aspects of electron beam dynamics, FEL exponential regime with gain guiding, start-up from noise, seeding and harmonic generation. These experiments will advance the state of FEL research and lead towards future dedicated users' facilities.
Milestone experiments for single pass UV/X-ray FELs
International Nuclear Information System (INIS)
Ben-Zvi, I.
1994-01-01
In the past decade, significant advances have been made in the theory and technology of high brightness electron beams and single pass FELS. These developments facilitate the construction of practical UV and X-ray FELs and has prompted proposals to the DOE for the construction of such facilities. There are several important experiments to be performed before committing to the construction of dedicated user facilities. Two experiments are under construction in the IR, the UCLA Self Amplified Spontaneous Emission experiment and the BNL laser seeded Harmonic Generation experiment. A multi-institution collaboration is being organized about a 210 MeV electron linac available at BNL and the 10 meter tong NISUS wiggler. This experiment will be done in the UV and will test various experimental aspects of electron beam dynamics, FEL exponential regime with gain guiding, start up from noise, seeding and harmonic generation. These experiments will advance the state of FEL research and lead towards future dedicated users' facilities
Directory of Open Access Journals (Sweden)
Tomohiro Hattori
2015-01-01
Full Text Available The continuous flow Suzuki-Miyaura reaction between various haloarenes and arylboronic acids was successfully achieved within only ca. 20 s during the single-pass through a cartridge filled with palladium on carbon (Pd/C. No palladium leaching was observed in the collected reaction solution by atomic absorption spectrometry (detection limit: 1 ppm.
Rates of Return on Flow-Through Shares: Investors and Governments Beware
Directory of Open Access Journals (Sweden)
Vijay Jog
2016-02-01
Full Text Available Canada’s tax code allows the use of flow-through shares for mining and oil and gas companies on the assumption that they are a good way to spur new productive exploration and are also beneficial to investors. In reality, it appears that flow-through shares are lousy for both. Flow-through shares are designed for corporations that cannot make good use of expense deductions from their taxes and so, through the use of these special type of shares, can pass along their expenses for shareholders to deduct from their own income taxes. This tax break is not insignificant: The amount of revenue foregone by the federal government due to flow-through shares and the related Mineral Exploration Tax Credit averaged $440 million every year between 2007 and 2012. But the steepest price has arguably been borne by investors, with returns on flow-through shares performing extraordinarily poorly. For small companies that issued these shares, the annualized absolute return was a nearly 100 per cent loss. For larger companies, the returns were not as bad — negative 14 per cent — but still a loss. And if adjusted for corresponding benchmarks, the returns were even worse. From the $2.5 billion raised from Canadians using flow-through shares, investors have lost $1.2 billion. Certainly these results would indicate that flow-through shares are hardly helping Canadian explorers strike lucrative new discoveries (it is impossible to say whether the limited success some larger companies had in locating productive assets, using flow-through shares, would not have occurred anyway. Meanwhile, these share issues, bearing the imprimatur of a special government right and the incentive of an investor tax benefit, have likely led to market distortions, luring capital that might have otherwise gone to more productive and rewarding investments. Compounding matters is the very real possibility that those projects that were funded by flow-through shares, but would have been
Estimates for the probability of survival of electrons in passing through a radiator
International Nuclear Information System (INIS)
Loos, J.
1977-01-01
Some calculations on the survival of electrons passing through various radiator thicknesses are tabulated. The results of these calculations should serve as a guide for expected attenuation of electrons in the beam when various Pb radiators are inserted
International Nuclear Information System (INIS)
Rivera-Sanfeliz, Gerant; Kinney, Thomas B.; Rose, Steven C.; Agha, Ayad K.M.; Valji, Karim; Miller, Franklin J.; Roberts, Anne C.
2005-01-01
Purpose: To describe our experience with ultrasound (US)-guided percutaneous liver biopsies using the INRAD 18G Express core needle biopsy system.Methods: One hundred and fifty-four consecutive percutaneous core liver biopsy procedures were performed in 153 men in a single institution over 37 months. The medical charts, pathology reports, and radiology files were retrospectively reviewed. The number of needle passes, type of guidance, change in hematocrit level, and adequacy of specimens for histologic analysis were evaluated.Results: All biopsies were performed for histologic staging of chronic liver diseases. The majority of patients had hepatitis C (134/153, 90.2%). All patients were discharged to home after 4 hr of postprocedural observation. In 145 of 154 (94%) biopsies, a single needle pass was sufficient for diagnosis. US guidance was utilized in all but one of the procedures (153/154, 99.4%). The mean hematocrit decrease was 1.2% (44.1-42.9%). Pain requiring narcotic analgesia, the most frequent complication, occurred in 28 of 154 procedures (18.2%). No major complications occurred. The specimens were diagnostic in 152 of 154 procedures (98.7%).Conclusions: Single-pass percutaneous US-guided liver biopsy with the INRAD 18G Express core needle biopsy system is safe and provides definitive pathologic diagnosis of chronic liver disease. It can be performed on an outpatient basis. Routine post-biopsy monitoring of hematocrit level in stable, asymptomatic patients is probably not warranted
Basic rules for various liquids passing through nuclear track membranes
International Nuclear Information System (INIS)
Guo Shilun; Hao Xiuhong; Wang Yulan; Fan Zhongjun; Zhao Yuhua; Zhao Chongde
1995-01-01
The authors describes the new understanding obtained from the studies of NTM for various liquid media, including: (1) basic rule of pure liquids passing through NTM; (2) various methods for the determination of viscosity of liquids by NTM; (3) determination of solute concentration in various solutions by NTM; (4) rapid separation of mixed liquids and chemical separation by NTM; (5) blocking phenomenon of NTM by solid particles in liquids and the blocking formula; and (6) basic rules of filtration of bacteria by NTM
Radiation of ultrarelativistic particles passing through ideal and mosaic crystals
International Nuclear Information System (INIS)
Afanas'ev, A.M.
1977-01-01
When a charged particle passes through an ideal crystal, then besides the transition radiation, a new kind of radiation, connected with the periodic structure of the crystal is produced. The influence of mosaic structure of a crystal on the intensity of this radiation is considered. Simple analytical expressions for the integral intensity of this radiation for the case of an ideal crystal are obtained. The results show, that the integral radiation intensity depends weakly on the degree of crystal perfection
Applicability estimation of flowmeter logging for detecting hydraulic pass
International Nuclear Information System (INIS)
Miyakawa, Kimio; Tanaka, Yasuji; Tanaka, Kazuhiro
1997-01-01
Estimation of the hydraulic pass governing hydrogeological structure contributes significantly to the siting HLW repository. Flowmeter logging can detect hydraulic passes by measuring vertical flow velocity of groundwater in the borehole. We reviewed application of this logging in situ. The hydraulic pass was detected with combination of ambient flow logging, with pumping and/or injecting induced flow logging. This application showed that the flowmeter logging detected hydraulic passes conveniently and accurately compared with other hydraulic tests. Hydraulic conductivity by using flowmeter logging was assessed above 10 -6 m/sec and within one order from comparison with injection packer tests. We suggest that appropriate application of the flowmeter logging for the siting is conducted before hydraulic tests because test sections and monitoring sections are decided rationally for procurement of quantitative hydraulic data. (author)
Equivalence of two models in single-phase multicomponent flow simulations
Wu, Yuanqing
2016-02-28
In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.
Equivalence of two models in single-phase multicomponent flow simulations
Wu, Yuanqing; Sun, Shuyu
2016-01-01
In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.
International Nuclear Information System (INIS)
Pickrell, P.W.
1985-10-01
A series of experiments has been performed in which UF 6 was released into flowing air in order to characterize the solid particulate material produced under non-static conditions. In two of the experiments, the aerosol was allowed to stagnate in a static chamber after release and examined further but in the other experiments characterization was done only on material collected a few seconds after release. Transmission electron microscopy and mass measurement by cascaded impactor were used to characterize the aerosol particles which were usually single spheroids with little agglomeration in evidence. The goal of the work is to determine the chemistry and physics of the UF 6 -atmospheric moisture reaction under a variety of conditions so that information about resulting species and product morphologies is available for containment and removal (knockdown) studies as well as for dispersion plume modeling and toxicology studies. This report completes the milestone for reporting the information obtained from releases of UF 6 into flowing rather than static air. 26 figs., 3 tabs
International Nuclear Information System (INIS)
Jang, E.S.; Goak, J.C.; Lee, H.S.; Lee, S.H.; Han, J.H.; Lee, C.S.; Sok, J.H.; Seo, Y.H.; Park, K.S.; Lee, N.S.
2010-01-01
In the conventional carbon nanotube backlight units (CNT-BLUs), light passes through the phosphor-coated anode glass plate, which thus faces closely the thin film transistor (TFT) backplate of a liquid crystal display panel. This configuration makes heat dissipation structurally difficult because light emission and heat generation occur simultaneously at the anode. We propose a novel configuration of a CNT-BLU where the cathode rather than the anode faces the TFT backplate by turning it upside down. In this design, light passes through the transparent cathode glass plate while heating occurs at the anode. We demonstrated a novel design of CNT-BLU by fabricating transparent single-walled CNT field emitters on the cathode and by coating a reflecting metal layer on the anode. This study hopefully provides a clue to solve the anode-heating problem which would be inevitably confronted for high-luminance and large-area CNT-BLUs.
Kriechbaumer, Thomas; Blackburn, Kim; Gill, Andrew; Breckon, Toby; Everard, Nick; Wright, Ros; Rivas Casado, Monica
2014-05-01
may distract fish away from fish pass entrances. The initial steps of the framework development have focused on the challenge of precise spatial data referencing in areas with limited sky view to navigation satellites. Platform tracking with a motorised Total Station, various satellite-based positioning solutions and simultaneous localisation and mapping (SLAM) based on stereo images have been tested. The effect of errors in spatial data referencing on ADCP-derived maps of flow features and bathymetry will be quantified through simultaneous deployment of these navigation technologies and the ADCP. This will inform the selection of a cost-effective platform positioning system in practice. Further steps will cover the quantification of uncertainties in ADCP data caused by highly turbulent flows and the identification of suitable ADCP data sampling strategies at fish passes. The final framework for fish pass assessment can contribute to an improved understanding of the interaction of fish and the complex hydraulic river environment.
Sticherling, Christian; Müller, Dirk; Schaer, Beat A; Krüger, Silke; Kolb, Christof
2018-03-27
Many patients receiving cardiac resynchronization therapy (CRT) suffer from permanent atrial fibrillation (AF). Knowledge of the atrial rhythm is important to direct pharmacological or interventional treatment as well as maintaining AV-synchronous biventricular pacing if sinus rhythm can be restored. A single pass single-coil defibrillator lead with a floating atrial bipole has been shown to obtain reliable information about the atrial rhythm but has never been employed in a CRT-system. The purpose of this study was to assess the feasibility of implanting a single coil right ventricular ICD lead with a floating atrial bipole and the signal quality of atrial electrograms (AEGM) in CRT-defibrillator recipients with permanent AF. Seventeen patients (16 males, mean age 73 ± 6 years, mean EF 25 ± 5%) with permanent AF and an indication for CRT-defibrillator placement were implanted with a designated CRT-D system comprising a single pass defibrillator lead with a atrial floating bipole. They were followed-up for 103 ± 22 days using remote monitoring for AEGM transmission. All patients had at last one AEGM suitable for atrial rhythm diagnosis and of 100 AEGM 99% were suitable for visual atrial rhythm assessment. Four patients were discharged in sinus rhythm and one reverted to AF during follow-up. Atrial electrograms retrieved from a single-pass defibrillator lead with a floating atrial bipole can be reliably used for atrial rhythm diagnosis in CRT recipients with permanent AF. Hence, a single pass ventricular defibrillator lead with a floating bipole can be considered in this population. Copyright © 2018 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Jeong, Chang Joon; Jo, Chang Keun; Noh, Jae Man
2012-01-01
A concept of a deep-burn (DB) of trans uranic (TRU) elements in a high temperature reactor (HTR) has been proposed and studied with a single irradiation pass. However, there is still a significant amount of TRU after burn in an HTR. Therefore, it is necessary to burn more TRU in a fast reactor (FR) with repeated reprocessing such as a pyro-process. In this study, the fuel cycle calculations are performed and the results are compared for a singlepass DB-HHR scenario and a dual-pass sodium-cooled fast reactor (SFR) scenario. For the analysis, front-end and back-end parameters are compared. The calculations were performed by the DANESS (Dynamic Analysis of Nuclear Energy System Strategies), which is an integrated system dynamic fuel cycle analysis code
Yu, Wenxin; Zhu, Jiafang; Wang, Lizhen; Qiu, Yajing; Chen, Yijie; Yang, Xi; Chang, Lei; Ma, Gang; Lin, Xiaoxi
2018-03-27
To compare the efficacy and safety of double-pass pulsed dye laser (DWL) and single-pass PDL (SWL) in treating virgin port wine stain (PWS). The increase in the extent of vascular damage attributed to the use of double-pass techniques for PWS remains inconclusive. A prospective, side-by-side comparison with a histological study for virgin PWS is still lacking. Twenty-one patients (11 flat PWS, 10 hypertrophic PWS) with untreated PWS underwent 3 treatments at 2-month intervals. Each PWS was divided into three treatment sites: SWL, DWL, and untreated control. Chromametric and visual evaluation of the efficacy and evaluation of side effects were conducted 3 months after final treatment. Biopsies were taken at the treated sites immediately posttreatment. Chromametric and visual evaluation suggested that DWL sites showed no significant improvement compared with SWL (p > 0.05) in treating PWS. The mean depth of photothermal damage to the vessels was limited to a maximum of 0.36-0.41 mm in both SWL and DWL sides. Permanent side effects were not observed in any patients. Double-pass PDL does not enhance PWS clearance. To improve the clearance of PWS lesions, either the depth of laser penetration should be increased or greater photothermal damage to vessels should be generated.
Single-strand DNA molecule translocation through nanoelectrode gaps
International Nuclear Information System (INIS)
Zhao Xiongce; Payne, Christina M; Cummings, Peter T; Lee, James W
2007-01-01
Molecular dynamics simulations were performed to investigate the translocation of single-strand DNA through nanoscale electrode gaps under the action of a constant driving force. The application behind this theoretical study is a proposal to use nanoelectrodes as a screening gap as part of a rapid genomic sequencing device. Preliminary results from a series of simulations using various gap widths and driving forces suggest that the narrowest electrode gap that a single-strand DNA can pass is ∼1.5 nm. The minimum force required to initiate the translocation within nanoseconds is ∼0.3 nN. Simulations using DNA segments of various lengths indicate that the minimum initiation force is insensitive to the length of DNA. However, the average threading velocity of DNA varies appreciably from short to long DNA segments. We attribute such variation to the different nature of drag force experienced by the short and long DNA segments in the environment. It is found that DNA molecules deform significantly to fit in the shape of the nanogap during the translocation
Critical flow rate in a single phase flow. Blocking concept
International Nuclear Information System (INIS)
Giot, Michel
1978-01-01
After referring to the phenomena accompanying the appearance of a critical flow rate in a nozzle and presenting equations governing single phase flows, the critical condition is defined. Several particular cases are then examined; the horizontal and vertical isentropic flow, Fanno's flow and Raleigh's and the isothermal flow. The entropy deviation is calculated on either side of a normal impact. To conclude, the link existing between the concepts of critical flow and the propagation rate of small perturbations is demonstrated. To do so, the method of perturbations, that of Prandtl and that of characteristic directions are applied in turn [fr
Spatial statistics for predicting flow through a rock fracture
International Nuclear Information System (INIS)
Coakley, K.J.
1989-03-01
Fluid flow through a single rock fracture depends on the shape of the space between the upper and lower pieces of rock which define the fracture. In this thesis, the normalized flow through a fracture, i.e. the equivalent permeability of a fracture, is predicted in terms of spatial statistics computed from the arrangement of voids, i.e. open spaces, and contact areas within the fracture. Patterns of voids and contact areas, with complexity typical of experimental data, are simulated by clipping a correlated Gaussian process defined on a N by N pixel square region. The voids have constant aperture; the distance between the upper and lower surfaces which define the fracture is either zero or a constant. Local flow is assumed to be proportional to local aperture cubed times local pressure gradient. The flow through a pattern of voids and contact areas is solved using a finite-difference method. After solving for the flow through simulated 10 by 10 by 30 pixel patterns of voids and contact areas, a model to predict equivalent permeability is developed. The first model is for patterns with 80% voids where all voids have the same aperture. The equivalent permeability of a pattern is predicted in terms of spatial statistics computed from the arrangement of voids and contact areas within the pattern. Four spatial statistics are examined. The change point statistic measures how often adjacent pixel alternate from void to contact area (or vice versa ) in the rows of the patterns which are parallel to the overall flow direction. 37 refs., 66 figs., 41 tabs
Nakamura, S.; Scott, J. N.
1993-01-01
A two-dimensional model to solve compressible Navier-Stokes equations for the flow through stator and rotor blades of a turbine is developed. The flow domains for the stator and rotor blades are coupled by the Chimera method that makes grid generation easy and enhances accuracy because the area of the grid that have high turning of grid lines or high skewness can be eliminated from the computational domain after the grids are generated. The results of flow computations show various important features of unsteady flows including the acoustic waves interacting with boundary layers, Karman vortex shedding from the trailing edge of the stator blades, pulsating incoming flow to a rotor blade from passing stator blades, and flow separation from both suction and pressure sides of the rotor blades.
Sutton, Steven C.; Rinaldi, M. T. S.; Vukovinsky, K. E.
2001-01-01
This study was undertaken to determine whether the gravimetric method provided an accurate measure of water flux correction and to compare the gravimetric method with methods that employ nonabsorbed markers (eg, phenol red and 14C-PEG-3350). Phenol red, 14C-PEG-3350, and 4-[2-[[2-(6-amino-3-pyridinyl)-2-hydroxyethyl]amino]ethoxy]-methyl ester, (R)-benzene acetic acid (Compound I) were co-perfused in situ through the jejunum of 9 anesthetized rats (single-pass intestinal perfusion [SPIP]). Wat...
A model of single and two-phase flow (critical or not) through cracks
International Nuclear Information System (INIS)
Seynhaeve, J.M.; Giot, M.; Granger, S.; Pages, D.
1995-07-01
The leaks through steam-generator cracks are the subject of research carried out in cooperation between EDF and UCL. A model to predict the mass flow rate with inlet subcooling has been developed, validated and published. The model takes into account the persistence of some metastable liquid in the crack. The present paper improves and extends the model, by making it applicable to all kinds of conditions prevailing in the S.G. tubes: not only subcooled water, but also saturated water, steam-water mixtures, saturated dry steam or superheated steam. Therefore, the flow at the crack inlet is analyzed and appropriate methods to initialize the numerical integration of the flow equations along the crack are proposed. The extensions of the model are still in the process of validation. However, a sensitivity analysis of its results has been made and is presented. (author)
Fluid flow through replicated microcellular materials in the Darcy-Forchheimer regime
International Nuclear Information System (INIS)
Weber, L.; Ingram, D.; Guardia, S.; Athanasiou-Ioannou, A.; Mortensen, A.
2017-01-01
We extend here a “bottleneck” flow model derived earlier for incompressible fluids flowing under creeping flow conditions [Despois, J. and Mortensen, A: Acta Materialia 53 (2005) 1381] to flow regimes where inertial losses are no longer negligible, causing the governing flow law to deviate from Darcy's law and become the Darcy-Forchheimer law. The proposed law is compared with measurements of the Darcian permeability K_D and of the Forchheimer coefficient C in forced-flow of air through microcellular aluminium made by the replication process. The geometrical features of the cellular medium are varied in terms of volume fraction of porosity (in the range of 0.66–0.86) and the average cell diameter from (108–425 μm). As found previously in measurements with water, the Darcy permeability of the foams for airflow is also reasonably well captured by the model. In the Forchheimer-regime the model gives good quantitative agreement with data if one assumes that the amount of air kinetic energy that is dissipated when passing across each bottleneck linking one pore to its neighbour along the fluid flow path corresponds to the difference, in a stream of constant cross-sectional area, between a uniform fluid velocity profile and the non-uniform profile that is created by the no-slip condition along the window boundary.
Janine Aron; Greg Farrell; John Muellbauer; Peter Sinclair
2012-01-01
Understanding how import prices adjust to exchange rates helps anticipate inflation effects and monetary policy responses. This paper examines exchange rate pass-through to the monthly import price index in South Africa during 1980–2009. Various short-run pass-through estimates are calculated simply without recourse to a full structural model, yet without neglecting the long-run relationships between prices or the effects of previous import price changes, and controlling for domestic and fore...
Single-sided natural ventilation through a centre-pivot roof window
DEFF Research Database (Denmark)
Iqbal, Ahsan; Nielsen, Peter V.; Gunner, Amalie
2014-01-01
The characteristics of centre pivot roof windows for wind driven single-sided ventilation has not been studied before. These types of windows are dominating roof windows in Europe. Knowledge of flow characteristics of this kind of window is essential for accurate designing of natural ventilation...... systems. In this study, numerical methods were used to characterise a centre-pivot roof window for wind-driven single-sided ventilation. A 1:20 scale model house of the Energy Flex House (Denmark) was used in this study. The roof slope was 36o. It was found that the single-sided ventilation through...
International Nuclear Information System (INIS)
Pivovarov, Yu.L.; Shirokov, A.A.; Vorobiev, S.A.
1990-01-01
The energy dependence of electromagnetic excitation and electromagnetic disintegration cross sections for relativistic nuclei passing through crystals is investigated both theoretically and by means of computer simulation. For electromagnetic excitation, resonant peaks are found at definite energy values. An increase of electromagnetic excitation and disintegration cross sections in crystals at very high energies is found to be due to coherent addition of amplitudes. Numerical results are presented for the electric dipole excitation of fluorine nuclei and electromagnetic deuteron disintegration. (orig.)
Static thermo-optic instability in double-pass fiber amplifiers
DEFF Research Database (Denmark)
Lægsgaard, Jesper
2016-01-01
A coupled-mode formalism, earlier used to describe transverse mode instabilities in single-pass optical fiber amplifiers, is extended to the case of double-pass amplifiers. Contrary to the single-pass case, it is shown that the thermo-optic nonlinearity can couple light at the same frequency...... between the LP01 and LP11 modes, leading to a static deformation of the output beam profile. This novel phenomenon is caused by the interaction of light propagating in either direction with thermo-optic index perturbations caused by light propagating in the opposite direction. The threshold power...... for the static deformation is found to be several times lower than what is typically found for the dynamic modal instabilities observed in single-pass amplifiers. (C) 2016 Optical Society of America...
Film boiling from spheres in single- and two-phase flow
International Nuclear Information System (INIS)
Liu, C.; Theofanous, T.G.; Yuen, W.W.
1992-01-01
Experimental data on film boiling heat transfer from single, inductively heated, spheres in single- and two-phase flow (saturated water and steam, respectively) are presented. In the single-phase-flow experiments water velocities ranged from 0.1 to 2.0 m/s; in the two-phase-flow experiments superficial water and steam velocities covered 0.1 to 0.6 m/s and 4 to 10 m/s, respectively. All experiments were run at atmospheric pressure and with sphere temperatures from 900C down to quenching. Limited interpretations of the single-phase- flow data are possible, but the two-phase-flow data are new and unique
Substance flows through the economy and environment of a region : Part I: Systems definition
Van Der Voet, Ester; Kleijn, René; Van Oers, Lauran; Heijungs, Reinout; Huele, Ruben; Mulder, Paul
1995-01-01
In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method is presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. This article is dedicated
Optical performance of multifocal soft contact lenses via a single-pass method.
Bakaraju, Ravi C; Ehrmann, Klaus; Falk, Darrin; Ho, Arthur; Papas, Eric
2012-08-01
A physical model eye capable of carrying soft contact lenses (CLs) was used as a platform to evaluate optical performance of several commercial multifocals (MFCLs) with high- and low-add powers and a single-vision control. Optical performance was evaluated at three pupil sizes, six target vergences, and five CL-correcting positions using a spatially filtered monochromatic (632.8 nm) light source. The various target vergences were achieved by using negative trial lenses. A photosensor in the retinal plane recorded the image point-spread that enabled the computation of visual Strehl ratios. The centration of CLs was monitored by an additional integrated en face camera. Hydration of the correcting lens was maintained using a humidity chamber and repeated instillations of rewetting saline drops. All the MFCLs reduced performance for distance but considerably improved performance along the range of distance to near target vergences, relative to the single-vision CL. Performance was dependent on add power, design, pupil, and centration of the correcting CLs. Proclear (D) design produced good performance for intermediate vision, whereas Proclear (N) design performed well at near vision (p 4 mm in diameter. Acuvue Oasys bifocal produced performance comparable with single-vision CL for most vergences. Direct measurement of single-pass images at the retinal plane of a physical model eye used in conjunction with various MFCLs is demonstrated. This method may have utility in evaluating the relative effectiveness of commercial and prototype designs.
Integral Transport Analysis Results for Ions Flowing Through Neutral Gas
Emmert, Gilbert; Santarius, John
2017-10-01
Results of a computational model for the flow of energetic ions and neutrals through a background neutral gas will be presented. The method models reactions as creating a new source of ions or neutrals if the energy or charge state of the resulting particle is changed. For a given source boundary condition, the creation and annihilation of the various species is formulated as a 1-D Volterra integral equation that can quickly be solved numerically by finite differences. The present work focuses on multiple-pass, 1-D ion flow through neutral gas and a nearly transparent, concentric anode and cathode pair in spherical, cylindrical, or linear geometry. This has been implemented as a computer code for atomic (3He, 3He +, 3He + +) and molecular (D, D2, D-, D +, D2 +, D3 +) ion and neutral species, and applied to modeling inertial-electrostatic connement (IEC) devices. The code yields detailed energy spectra of the various ions and energetic neutral species. Calculations for several University of Wisconsin IEC and ion implantation devices will be presented. Research supported by US Dept. of Homeland Security Grant 2015-DN-077-ARI095, Dept. of Energy Grant DE-FG02-04ER54745, and the Grainger Foundation.
Generation of coherent soft x-rays using a single-pass free-electron laser amplifier
International Nuclear Information System (INIS)
Wang, T.F.; Goldstein, J.C.; Newnam, B.E.; McVey, B.D.
1988-01-01
We consider a single-pass free-electron laser (FEL) amplifier, driven by an rf-linac followed by a damping ring for reduced emittance, for use in generating coherent light in the soft x-ray region. The dependence of the optical gain on electron-beam quality, studied with the three-dimensional FEL simulation code FELEX, is given and related to the expected power of self-amplified spontaneous emission. We discuss issues for the damping ring designed to achieve the required electron beam quality. The idea of a multipass regenerative amplifier is also presented
Marginal CO2 cost pass-through under imperfect competition in power markets
International Nuclear Information System (INIS)
Chernyavs'ka, Liliya; Gulli, Francesco
2008-01-01
In line with economic theory, carbon ETS determines a rise in marginal cost equal to the carbon opportunity cost regardless of whether carbon allowances are allocated free of charge or not. This paper aims at evaluating to what extent firms in imperfectly competitive markets will pass-through into electricity prices the increase in cost. By using the load duration curve approach and the dominant firm with competitive fringe model, we show that the result is ambiguous. The increase in price can be either lower or higher than the marginal CO 2 cost, depending on several structural factors: the degree of market concentration, the available capacity (whether there is excess capacity or not), the power plant mix in the market and the power demand level (peak vs. off-peak hours). The empirical analysis of the Italian context (an emblematic case of imperfectly competitive market), which can be split into four sub-markets with different structural features, provides a contribution supporting the model predictions. Market power, therefore, would determine a significant deviation from the 'full pass-through' rule but we cannot know the sign of this deviation, a priori, i.e. without before taking carefully into account the structural features of the power market. (author)
DeGraff, J.V.; Wagner, D.L.; Gallegos, A.J.; DeRose, M.; Shannon, C.; Ellsworth, T.
2011-01-01
On July 12, 2008, two convective cells about 155 km apart produced a brief period of intense rainfall triggering large debris flows in the southern Sierra Nevada. The northernmost cell was centered over Oak Creek Canyon, an east-flowing drainage, and its tributaries near Independence, CA, USA. About 5:00 P.M., debris flows passed down the South Fork and North Fork of Oak Creek to merge into a large single feature whose passage affected the historic Mt. Whitney Fish hatchery and blocked California State Highway 395. At about the same time, the southernmost cell was largely centered over Erskine Creek, a main tributary of the west-flowing Kern River. Debris flows issued from several branches to coalesce into a large debris flow that passed along Erskine Creek, through the town of Lake Isabella, CA, USA and into the Kern River. It was observed reaching Lake Isabella about 6:30 P.M. Both debris flows caused significant disruption and damage to local communities. ?? 2011 Springer-Verlag.
Mineral assemblage transformation of a metakaolin-based waste form after geopolymer encapsulation
Energy Technology Data Exchange (ETDEWEB)
Williams, Benjamin D., E-mail: Benjamin.Williams@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-54, Richland, WA 99352 (United States); Neeway, James J., E-mail: James.Neeway@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-54, Richland, WA 99352 (United States); Snyder, Michelle M.V., E-mail: Michelle.ValentaSnyder@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-54, Richland, WA 99352 (United States); Bowden, Mark E., E-mail: Mark.Bowden@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-54, Richland, WA 99352 (United States); Amonette, James E., E-mail: Jim.Amonette@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-54, Richland, WA 99352 (United States); Arey, Bruce W., E-mail: Bruce.Arey@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-54, Richland, WA 99352 (United States); Pierce, Eric M., E-mail: pierceem@ornl.gov [Oak Ridge National Laboratory, PO Box 2008, MS-6035, Room 372, Oak Ridge, TN 37831 (United States); Brown, Christopher F., E-mail: Christopher.Brown@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-54, Richland, WA 99352 (United States); Qafoku, Nikolla P., E-mail: Nik.Qafoku@pnnl.gov [Pacific Northwest National Laboratory, PO Box 999, MSIN P7-54, Richland, WA 99352 (United States)
2016-05-15
Mitigation of hazardous and radioactive waste can be improved through conversion of existing waste to a more chemically stable and physically robust waste form. One option for waste conversion is the fluidized bed steam reforming (FBSR) process. The resulting FBSR granular material was encapsulated in a geopolymer matrix referred to here as Geo-7. This provides mechanical strength for ease in transport and disposal. However, it is necessary to understand the phase assemblage evolution as a result of geopolymer encapsulation. In this study, we examine the mineral assemblages formed during the synthesis of the multiphase ceramic waste form. The FBSR granular samples were created from waste simulant that was chemically adjusted to resemble Hanford tank waste. Another set of samples was created using Savannah River Site Tank 50 waste simulant in order to mimic a blend of waste collected from 68 Hanford tank. Waste form performance tests were conducted using the product consistency test (PCT), the Toxicity Characteristic Leaching Procedure (TCLP), and the single-pass flow-through (SPFT) test. X-ray diffraction analyses revealed the structure of a previously unreported NAS phase and indicate that monolith creation may lead to a reduction in crystallinity as compared to the primary FBSR granular product. - Highlights: • Simulated Hanford waste was treated by the Fluidized Bed Steam Reformer (FBSR) process. • The FBSR granular product was encapsulated in a geopolymer monolith. • Leach tests were performed to examine waste form performance. • XRD revealed the structure of a previously unreported sodium aluminosilicate phase. • Monolithing of granular waste forms may lead to a reduction in crystallinity.
Discharge Coefficient Measurements for Flow Through Compound-Angle Conical Holes with Cross-Flow
Directory of Open Access Journals (Sweden)
M. E. Taslim
2004-01-01
Full Text Available Diffusion-shaped film holes with compound angles are currently being investigated for high temperature gas turbine airfoil film cooling. An accurate prediction of the coolant blowing rate through these film holes is essential in determining the film effectiveness. Therefore, the discharge coefficients associated with these film holes for a range of hole pressure ratios is essential in designing airfoil cooling circuits. Most of the available discharge coefficient data in open literature has been for cylindrical holes. The main objective of this experimental investigation was to measure the discharge coefficients for subsonic as well as supersonic pressure ratios through a single conical-diffusion hole. The conical hole has an exit-to-inlet area ratio of 4, a nominal flow length-to-inlet diameter ratio of 4, and an angle with respect to the exit plane (inclination angle of 0°, 30°, 45°, and 60°. Measurements were performed with and without a cross-flow. For the cases with a cross-flow, discharge coefficients were measured for each of the hole geometries and 5 angles between the projected conical hole axis and the cross-flow direction of 0°, 45°, 90°, 135°, and 180°. Results are compared with available data in open literature for cylindrical film holes as well as limited data for conical film holes.
Directory of Open Access Journals (Sweden)
Chii-Dong Ho
2016-01-01
Full Text Available The improvement of device performance of a recycling solar air heater featuring a wire mesh packing was investigated experimentally and theoretically. The application of the wire mesh packing and recycle-effect concept to the present study were proposed aiming to strengthen the convective heat-transfer coefficient due to increased turbulence. Comparisons were made among different designs, including the single-pass, flat-plate double-pass and recycling double-pass wire mesh packed operations. The collector efficiency of the recycling double-pass wire mesh packed solar air heater was much higher than that of the other configurations for various recycle ratios and mass flow rates scenarios. The power consumption increment due to implementing wire mesh in solar air heaters was also discussed considering the economic feasibility. A fairly good agreement between theoretical predictions and experimental measurements was achieved with an analyzed error of 1.07%–9.32%.
Single-phase flow and flow boiling of water in horizontal rectangular microchannels
Mirmanto
2013-01-01
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University The current study is part of a long term experimental project devoted to investigating single-phase flow pressure drop and heat transfer, flow boiling pressure drop and heat transfer, flow boiling instability and flow visualization of de-ionized water flow in microchannels. The experimental facility was first designed and constructed by S. Gedupudi (2009) and in the present study; ...
Wit, PJ; vanderMei, HC; Busscher, HJ
1997-01-01
By allowing an air-bubble to pass through a parallel plate flow chamber with negatively charged, colloidal polystyrene particles adhering to the bottom collector plate of the chamber, the detachment of adhering particles stimulated by surface tension forces induced by the passage of a liquid-air
Homogenization via the strong-permittivity-fluctuation theory with nonzero depolarization volume
Mackay, Tom G.
2004-08-01
The depolarization dyadic provides the scattering response of a single inclusion particle embedded within a homogenous background medium. These dyadics play a central role in formalisms used to estimate the effective constitutive parameters of homogenized composite mediums (HCMs). Conventionally, the inclusion particle is taken to be vanishingly small; this allows the pointwise singularity of the dyadic Green function associated with the background medium to be employed as the depolarization dyadic. A more accurate approach is pursued in this communication by taking into account the nonzero spatial extent of inclusion particles. Depolarization dyadics corresponding to inclusion particles of nonzero volume are incorporated within the strong-permittivity-fluctuation theory (SPFT). The linear dimensions of inclusion particles are assumed to be small relative to the electromagnetic wavelength(s) and the SPFT correlation length. The influence of the size of inclusion particles upon SPFT estimates of the HCM constitutive parameters is investigated for anisotropic dielectric HCMs.In particular, the interplay between correlation length and inclusion size is explored.
Ally, Abdallah K; Meng, Yang; Chakraborty, Ratula; Dobson, Paul W; Seaton, Jonathan S; Holmes, John; Angus, Colin; Guo, Yelan; Hill-McManus, Daniel; Brennan, Alan; Meier, Petra S
2014-12-01
Effective use of alcohol duty to reduce consumption and harm depends partly on retailers passing duty increases on to consumers via price increases, also known as 'pass-through'. The aim of this analysis is to provide evidence of UK excise duty and sales tax (VAT) pass-through rates for alcohol products at different price points. March 2008 to August 2011, United Kingdom. Panel data quantile regression estimating the effects of three duty changes, two VAT changes and one combined duty and VAT change on UK alcohol prices, using product-level supermarket price data for 254 alcohol products available weekly. Products were analysed in four categories: beers, ciders/ready to drink (RTDs), spirits and wines. Within all four categories there exists considerable heterogeneity in the level of duty pass-through for cheaper versus expensive products. Price increases for the cheapest 15% of products fall below duty rises (undershifting), while products sold above the median price are overshifted (price increases are higher than duty increases). The level of undershifting is greatest for beer [0.85 (0.79, 0.92)] and spirits [0.86 (0.83, 0.89)]. Undershifting affects approximately 67% of total beer sales and 38% of total spirits sales. Alcohol retailers in the United Kingdom appear to respond to increases in alcohol tax by undershifting their cheaper products (raising prices below the level of the tax increase) and overshifting their more expensive products (raising prices beyond the level of the tax increase). This is likely to impact negatively on tax policy effectiveness, because high-risk groups favour cheaper alcohol and undershifting is likely to produce smaller consumption reductions. © 2014 Society for the Study of Addiction.
Modeling groundwater flow to elliptical lakes and through multi-aquifer elliptical inhomogeneities
Bakker, Mark
2004-05-01
Two new analytic element solutions are presented for steady flow problems with elliptical boundaries. The first solution concerns groundwater flow to shallow elliptical lakes with leaky lake beds in a single-aquifer. The second solution concerns groundwater flow through elliptical cylinder inhomogeneities in a multi-aquifer system. Both the transmissivity of each aquifer and the resistance of each leaky layer may differ between the inside and the outside of an inhomogeneity. The elliptical inhomogeneity may be bounded on top by a shallow elliptical lake with a leaky lake bed. Analytic element solutions are obtained for both problems through separation of variables of the Laplace and modified-Helmholtz differential equations in elliptical coordinates. The resulting equations for the discharge potential consist of infinite sums of products of exponentials, trigonometric functions, and modified-Mathieu functions. The series are truncated but still fulfill the differential equation exactly; boundary conditions are met approximately, but up to machine accuracy provided enough terms are used. The head and flow may be computed analytically at any point in the aquifer. Examples are given of uniform flow through an elliptical lake, a well pumping near two elliptical lakes, and uniform flow through three elliptical inhomogeneities in a multi-aquifer system. Mathieu functions may be applied in a similar fashion to solve other groundwater flow problems in semi-confined aquifers and leaky aquifer systems with elliptical internal or external boundaries.
Yamaguchi, H.; Takamori, K.; Perrier, P.; Graur, I.; Matsuda, Y.; Niimi, T.
2016-09-01
The viscous slip coefficient for helium-argon binary gas mixture is extracted from the experimental values of the mass flow rate through a microtube. The mass flow rate is measured by the constant-volume method. The viscous slip coefficient was obtained by identifying the measured mass flow rate through a microtube with the corresponding analytical expression, which is a function of the Knudsen number. The measurements were carried out in the slip flow regime where the first-order slip boundary condition can be applied. The measured viscous slip coefficients of binary gas mixtures exhibit a concave function of the molar ratio of the mixture, showing a similar profile with numerical results. However, from the detailed comparison between the measured and numerical values with the complete and incomplete accommodation at a surface, it is inappropriate to estimate the viscous slip coefficient for the mixture numerically by employing separately measured tangential momentum accommodation coefficient for each component. The time variation of the molar ratio in the downstream chamber was measured by sampling the gas from the chamber using the quadrupole mass spectrometer. In our measurements, it is indicated that the volume flow rate of argon is larger than that of helium because of the difference in the tangential momentum accommodation coefficient.
EXPERIMENTAL STUDY ON DOUBLE PASS SOLAR AIR HEATER WITH MESH LAYERS AS ABSORBER PLATE
Directory of Open Access Journals (Sweden)
Raheleh Nowzaria
2014-01-01
Full Text Available The double pass solar air heater is constructed and tested for thermal efficiency at a geographic location of Cyprus in the city of Famagusta. The absorber plate was replaced by fourteen steel wire mesh layers, 0.2 × 0.2 cm in cross section opening, and they were fixed in the duct parallel to the glazing. The distance between each set of wire mesh layers is 0.5cm to reduce the pressure drop. The wire mesh layers were painted with black before installing them into the collector. The obtained results show that as the mass flow rate increases, the efficiency of the system also increases. The temperature difference (ΔT between the inlet and outlet air through the system increases as the mass flow rate decreases. The maximum ΔT (53°C is achieved at the flow rate of 0.011 kg/s. The range of the mass flow rate used in this work is between 0.011 and 0.037 kg/s. It is also found that the average efficiency obtained for the double pass air collector is 53.7% for the mass flow rate of 0.037 kg/s.
High-Accuracy Elevation Data at Large Scales from Airborne Single-Pass SAR Interferometry
Directory of Open Access Journals (Sweden)
Guy Jean-Pierre Schumann
2016-01-01
Full Text Available Digital elevation models (DEMs are essential data sets for disaster risk management and humanitarian relief services as well as many environmental process models. At present, on the hand, globally available DEMs only meet the basic requirements and for many services and modeling studies are not of high enough spatial resolution and lack accuracy in the vertical. On the other hand, LiDAR-DEMs are of very high spatial resolution and great vertical accuracy but acquisition operations can be very costly for spatial scales larger than a couple of hundred square km and also have severe limitations in wetland areas and under cloudy and rainy conditions. The ideal situation would thus be to have a DEM technology that allows larger spatial coverage than LiDAR but without compromising resolution and vertical accuracy and still performing under some adverse weather conditions and at a reasonable cost. In this paper, we present a novel single pass In-SAR technology for airborne vehicles that is cost-effective and can generate DEMs with a vertical error of around 0.3 m for an average spatial resolution of 3 m. To demonstrate this capability, we compare a sample single-pass In-SAR Ka-band DEM of the California Central Valley from the NASA/JPL airborne GLISTIN-A to a high-resolution LiDAR DEM. We also perform a simple sensitivity analysis to floodplain inundation. Based on the findings of our analysis, we argue that this type of technology can and should be used to replace large regions of globally available lower resolution DEMs, particularly in coastal, delta and floodplain areas where a high number of assets, habitats and lives are at risk from natural disasters. We conclude with a discussion on requirements, advantages and caveats in terms of instrument and data processing.
Polyphosphate Amendments for In-Situ Immobilization of Uranium Plumes
International Nuclear Information System (INIS)
Wellman, Dawn M.; Icenhower, Jonathan P.; Pierce, Eric M.; McNamara, Bruce K.; Burton, Sarah D.; Geiszler, Keith N.; Baum, Steven R.; Butler, Bart C.; R.F. Olfenbuttel; P.J. White
2005-01-01
A multi-faceted approach has been taken to address basic science questions with regards to the efficacy of utilizing phosphate amendments for subsurface immobilization of uranium plumes. Hydraulically saturated and unsaturated column tests demonstrate the ability of polyphosphate compounds to control the precipitation kinetics of insoluble phosphate minerals and optimize conditions for controlled application of phosphate amendments for subsurface remediation. X-Ray micro-focus tomography results illustrate long-term effects of phosphate mineralization on hydraulic conductivity. 31P NMR has been utilized to quantify the effect of sedimentary and aqueous components on the in-situ hydrolysis kinetics of condensed polyphosphates. Single-pass flow-through (SPFT) tests have been conducted to evaluate the longevity and quantify the effects of aqueous organic material on the dissolution kinetics of autunite minerals, X1-2[(UO2)(PO4)]2nH2O. Preliminary results indicate: (1) autunite minerals will precipitate within 1-2 months given a 0.05 M phosphate concentration and 10-6 M aqueous uranium concentration, under hydraulically saturated conditions; (2) polyphosphate chain lengths can be optimized for specific site conditions, given thorough knowledge of the subsurface environment; (3) the release of uranium from autunite minerals appears to be 6-7 order of magnitude slower than uranium (UO2) minerals formed by iron barrier reduction; and (4) understanding secondary uranyl-phase formation is necessary for predicting the long-term fate of uranium in the environment
A Novel Single Pass Authenticated Encryption Stream Cipher for Software Defined Radios
DEFF Research Database (Denmark)
Khajuria, Samant
2012-01-01
to propose cryptographic services such as confidentiality, integrity and authentication. Therefore, integration of security services into SDR devices is essential. Authenticated Encryption schemes donate the class of cryptographic algorithms that are designed for protecting both message confidentiality....... This makes authenticated encryption very attractive for low-cost low-power hardware implementations, as it allows for the substantial decrease in the circuit area and power consumed compared to the traditional schemes. In this thesis, an authenticated encryption scheme is proposed with the focus of achieving...... high throughput and low overhead for SDRs. The thesis is divided into two research topics. One topic is the design of a 1-pass authenticated encryption scheme that can accomplish both message secrecy and authenticity in a single cryptographic primitive. The other topic is the implementation...
Wang, Rongyang; Wei, Yikun; Wu, Chuanyu; Sun, Liang; Zheng, Wenguang
2018-01-01
The immersed boundary-lattice Boltzmann method (IB-LBM) was used to examine the motion and deformation of three elastic red blood cells (RBCs) during Poiseuille flow through constricted microchannels. The objective was to determine the effects of the degree of constriction and the Reynolds (Re) number of the flow on the physical characteristics of the RBCs. It was found that, with decreasing constriction ratio, the RBCs experienced greater forced deformation as they squeezed through the constriction area compared to at other parts of the microchannel. It was also observed that a longer time was required for the RBCs to squeeze through a narrower constriction. The RBCs subsequently regained a stable shape and gradually migrated toward the centerline of the flow beyond the constriction area. However, a sick RBC was observed to be incapable of passing through a constricted vessel with a constriction ratio ≤1/3 for Re numbers below 0.40.
International Nuclear Information System (INIS)
Damm, F.C.
1975-01-01
The unique gas dynamic laser provides outward radial supersonic flow from a toroidal shaped stacked array of a plurality of nozzles, through a diffuser having ring shaped and/or linear shaped vanes, and through a cavity which is cylindrical and concentric with the stacked array, with the resultant laser beam passing through the housing parallel to the central axis of the diffuser which is coincident with the axis of the gas dynamic laser. Therefore, greater beam extraction flexibility is attainable, because of fewer flow shock disturbances, as compared to the conventional unidirectional flow gas dynamic laser in which unidirectional supersonic flow sweeps through a rectangular cavity and is exhausted through a two-dimensional diffuser. (auth)
The Double Burden of Malnutrition in Countries Passing through the Economic Transition.
Prentice, Andrew M
2018-01-01
Undernutrition in both its acute and chronic forms (wasting and stunting) is strongly inversely correlated with the wealth of nations. Consequently, as many low- and middle-income countries (LMICs) achieve economic advancement and pass through the so-called "nutrition transition," their rates of undernutrition decline. Many countries successfully achieved the Millennium Development Goal of halving undernutrition and whole continents have been transformed in recent decades. The exception is Africa where the slower rates of decline in the prevalence of undernutrition has been overtaken by population growth so that the absolute number of stunted children is rising. In many regions, economic transition is causing a rapid increase in the number of overweight and obese people. The rapidity of this rise is such that many nations bear the simultaneous burdens of under- and overnutrition; termed the "double burden" of malnutrition. This double burden, accompanied as it is by the unfinished agenda of high levels of infectious diseases, is crippling the health systems of many LMICs and thus requires urgent attention. Although the prognosis looks threatening for many poor countries, they have the advantage of being able to learn from the mistakes made by other nations that have passed through the transition before them. Concerted action across many arms of government would achieve huge future dividends in health and wealth for any nations that can grasp the challenge. © 2018 S. Karger AG, Basel.
Hoberecht, Mark A.
2010-01-01
As part of the Exploration Technology Development Program (ETDP) under the auspices of the Exploration Systems Mission Directorate (ESMD), NASA is developing both primary fuel cell power systems and regenerative fuel cell (RFC) energy storage systems within the fuel cell portion of the Energy Storage Project. This effort is being led by the NASA Glenn Research Center (GRC) in partnership with the NASA Johnson Space Center (JSC), Jet Propulsion Laboratory (JPL), NASA Kennedy Space Center (KSC), and industrial partners. The development goals are to improve fuel cell and electrolysis stack electrical performance, reduce system mass, volume, and parasitic power requirements, and increase system life and reliability. A major focus of this effort has been the parallel development of both flow-through and non-flow-through proton exchange membrane (PEM) primary fuel cell power systems. The plan has been, at the appropriate time, to select a single primary fuel cell technology for eventual flight hardware development. Ideally, that appropriate time would occur after both technologies have achieved a technology readiness level (TRL) of six, which represents an engineering model fidelity PEM fuel cell system being successfully tested in a relevant environment. Budget constraints in fiscal year 2009 and beyond have prevented NASA from continuing to pursue the parallel development of both primary fuel cell options. Because very limited data exists for either system, a toplevel, qualitative assessment based on engineering judgement was performed expeditiously to provide guidance for a selection. At that time, the non-flow-through technology was selected for continued development because of potentially major advantages in terms of weight, volume, parasitic power, reliability, and life. This author believes that the advantages are significant enough, and the potential benefits great enough, to offset the higher state of technology readiness of flow-through technology. This paper
A single molecule DNA flow stretching microscope for undergraduates
Williams, Kelly; Grafe, Brendan; Burke, Kathryn M.; Tanner, Nathan; van Oijen, Antoine M.; Loparo, Joseph; Price, Allen C.
2011-01-01
The design of a simple, safe, and inexpensive single molecule flow stretching instrument is presented. The instrument uses a low cost upright microscope coupled to a webcam for imaging single DNA molecules that are tethered in an easy to construct microfluidic flow cell. The system requires no
On-line study of growth kinetics of single hyphae of Aspergillus oryzae in a flow-through cell
DEFF Research Database (Denmark)
Christiansen, Torben; Spohr, Anders Bendsen; Nielsen, Jens Bredal
1999-01-01
Using image analysis the growth kinetics of the single hyphae of the filamentous fungus Aspergillus oryzae has been determined on-line in a flow-through cell at different glucose concentrations in the range from 26 mg L-1 to 20 g L-1. The tip extension rate of the individual hyphae can be described...... with saturation type kinetics with respect to the length of the hyphae. The maximum tip extension rate is constant for all hyphae measured at the same glucose concentration, whereas the saturation constant for the hyphae varies significantly between the hyphae even within the same hyphal element. When apical...... branching occurs, it is observed that the tip extension rate decreases temporarily. The number of branches formed on a hypha is proportional to the length of the hypha that exceeds a certain minimum length required to support the growth of a new branch. The observed kinetics has been used to simulate...
Permeameter studies of water flow through cement and clay borehole seals in granite, basalt and tuff
International Nuclear Information System (INIS)
South, D.L.; Daemen, J.J.K.
1986-10-01
Boreholes near a repository must be sealed to prevent rapid migration of radionuclide-contaminated water to the accessible environment. The objective of this research is to assess the performance of borehole seals under laboratory conditions, particularly with regard to varying stress fields. Flow through a sealed borehole is compared with flow through intact rock. Cement or bentonite seals have been tested in granite, basalt, and welded tuff. The main conclusion is that under laboratory conditions, existing commercial materials can form high quality seals. Triaxial stress changes about a borehole do not significantly affect seal performance if the rock is stiffer than the seal. Temperature but especially moisture variations (drying) significantly degrade the quality of cement seals. Performance partially recovers upon resaturation. A skillfully sealed borehole may be as impermeable as the host rock. Analysis of the influence of relative seal-rock permeabilities shows that a plug with permeability one order of magnitude greater than that of the rock results in a flow increase through the hole and surrounding rock of only 1-1/2 times compared to the undisturbed rock. Since a borehole is only a small part of the total rock mass, the total effect is even less pronounced. The simplest and most effective way to decrease flow through a rock-seal system is to increase the seal length, assuming it can be guaranteed that no dominant by-pass flowpath through the rock exists
Permeameter studies of water flow through cement and clay borehole seals in granite, basalt and tuff
Energy Technology Data Exchange (ETDEWEB)
South, D.L.; Daemen, J.J.K.
1986-10-01
Boreholes near a repository must be sealed to prevent rapid migration of radionuclide-contaminated water to the accessible environment. The objective of this research is to assess the performance of borehole seals under laboratory conditions, particularly with regard to varying stress fields. Flow through a sealed borehole is compared with flow through intact rock. Cement or bentonite seals have been tested in granite, basalt, and welded tuff. The main conclusion is that under laboratory conditions, existing commercial materials can form high quality seals. Triaxial stress changes about a borehole do not significantly affect seal performance if the rock is stiffer than the seal. Temperature but especially moisture variations (drying) significantly degrade the quality of cement seals. Performance partially recovers upon resaturation. A skillfully sealed borehole may be as impermeable as the host rock. Analysis of the influence of relative seal-rock permeabilities shows that a plug with permeability one order of magnitude greater than that of the rock results in a flow increase through the hole and surrounding rock of only 1-1/2 times compared to the undisturbed rock. Since a borehole is only a small part of the total rock mass, the total effect is even less pronounced. The simplest and most effective way to decrease flow through a rock-seal system is to increase the seal length, assuming it can be guaranteed that no dominant by-pass flowpath through the rock exists.
Effects of multi-pass arc welding on mechanical properties of carbon steel C25 plate
International Nuclear Information System (INIS)
Adedayo, S.M.; Babatunde, A.S.
2013-01-01
The effects of multi-pass welding on mechanical properties of C25 carbon steel plate were examined. Mild steel plate workpieces of 90 x 55 mm 2 area and 10 mm thickness with a 30 degrees vee weld-grooves were subjected to single and multi-pass welding. Toughness, hardness and tensile tests of single and multi-pass welds were conducted. Toughness values of the welds under double pass welds were higher than both single pass and unwelded alloy, at respective maximum values of 2464, 2342 and 2170 kN/m. Hardness values were reduced under double pass relative to single pass welding with both being lower than the value for unwelded alloy; the values were 40.5, 43.2 and 48.5 Rs respectively at 12 mm from the weld line. The tensile strength of 347 N/mm 2 under multi-pass weld was higher than single pass weld with value of 314 N/mm 2 . Therefore, the temperature distribution and apparent pre-heating during multi-pass welding increased the toughness and tensile strength of the weldments, but reduced the hardness. (au)
Paull, C. K.; Talling, P.; Maier, K. L.; Parsons, D. R.; Xu, J.; Caress, D. W.; Gwiazda, R.; Lundsten, E. M.; Anderson, K.; Barry, J.; Chaffey, M. R.; O'Reilly, T. C.; Rosenberger, K. J.; Gales, J. A.; McGann, M.; McCann, M. P.; Simmons, S.; Sumner, E.
2017-12-01
Sediment density flows flushing through submarine canyons carry globally significant amounts of material into the deep sea to form many of the largest sediment accumulations on Earth. Despite their global significance, these flows remain poorly understood because they have rarely been directly measured. Here we provide an initial overview of the recently completed Coordinated Canyon Experiment (CCE), which was undertaken specifically to provide detailed measurements of sediment density flows and their impact on seafloor morphology and sedimentology. No previous study has deployed as extensive an array of monitoring sensors along a turbidity current pathway. During the 18 months of the CCE, at least 15 sediment density flows were recorded within the axis of Monterey Canyon. Because no external triggers (i.e., earthquakes or floods) correlate with these flows, they must have originated as failures in the canyon floor or canyon flanks. Three flows ignited and ran out for > 50 km from water depths of 1,860 m, reaching velocities up to 8.1 m/s. The rest of the flows died out within the array. During these events, large objects on or in the canyon floor were displaced substantial distances downslope, including a 7.1 km downslope movement of an entire mooring; a 4.6 km displacement of an 860 kg instrument frame followed by repeated down canyon displacements of this same frame after it was entombed in sediment; and multiple depth changes of man-made boulders containing acceleration and pressure sensors. During this same time interval the canyon floor was mapped six times with autonomous underwater vehicles covering the canyon thalweg at the upper and lower end of the instrument array (200-540 and 1350-1880 m water depths). The repeated mapping surveys reveal that flows caused +3 to -3 m bathymetric changes within a continuous clearly defined 200 m wide swath running along the canyon axis in 540 m water depth. This study shows that sediment density flows caused massive
Effect of gas temperature on flow rate characteristics of an averaging pitot tube type flow meter
Energy Technology Data Exchange (ETDEWEB)
Yeo, Seung Hwa; Lee, Su Ryong; Lee, Choong Hoon [Seoul National University of Science and Technology, Seoul (Korea, Republic of)
2015-01-15
The flow rate characteristics passing through an averaging Pitot tube (APT) while constantly controlling the flow temperature were studied through experiments and CFD simulations. At controlled temperatures of 25, 50, 75, and 100 .deg .C, the flow characteristics, in this case the upstream, downstream and static pressure at the APT flow meter probe, were measured as the flow rate was increased. The flow rate through the APT flow meter was represented using the H-parameter (hydraulic height) obtained by a combination of the differential pressure and the air density measured at the APT flow meter probe. Four types of H-parameters were defined depending on the specific combination. The flow rate and the upstream, downstream and static pressures measured at the APT flow meter while changing the H-parameters were simulated by means of CFD. The flow rate curves showed different features depending on which type of H-parameter was used. When using the constant air density value in a standard state to calculate the H-parameters, the flow rate increased linearly with the H-parameter and the slope of the flow rate curve according to the H-parameter increased as the controlled target air temperature was increased. When using different air density levels corresponding to each target air temperature to calculate the H-parameter, the slope of the flow rate curve according to the H-parameter was constant and the flow rate curve could be represented by a single line. The CFD simulation results were in good agreement with the experimental results. The CFD simulations were performed while increasing the air temperature to 1200 K. The CFD simulation results for high air temperatures were similar to those at the low temperature ranging from 25 to 100 .deg. C.
Effect of gas temperature on flow rate characteristics of an averaging pitot tube type flow meter
International Nuclear Information System (INIS)
Yeo, Seung Hwa; Lee, Su Ryong; Lee, Choong Hoon
2015-01-01
The flow rate characteristics passing through an averaging Pitot tube (APT) while constantly controlling the flow temperature were studied through experiments and CFD simulations. At controlled temperatures of 25, 50, 75, and 100 .deg .C, the flow characteristics, in this case the upstream, downstream and static pressure at the APT flow meter probe, were measured as the flow rate was increased. The flow rate through the APT flow meter was represented using the H-parameter (hydraulic height) obtained by a combination of the differential pressure and the air density measured at the APT flow meter probe. Four types of H-parameters were defined depending on the specific combination. The flow rate and the upstream, downstream and static pressures measured at the APT flow meter while changing the H-parameters were simulated by means of CFD. The flow rate curves showed different features depending on which type of H-parameter was used. When using the constant air density value in a standard state to calculate the H-parameters, the flow rate increased linearly with the H-parameter and the slope of the flow rate curve according to the H-parameter increased as the controlled target air temperature was increased. When using different air density levels corresponding to each target air temperature to calculate the H-parameter, the slope of the flow rate curve according to the H-parameter was constant and the flow rate curve could be represented by a single line. The CFD simulation results were in good agreement with the experimental results. The CFD simulations were performed while increasing the air temperature to 1200 K. The CFD simulation results for high air temperatures were similar to those at the low temperature ranging from 25 to 100 .deg. C.
Energy Technology Data Exchange (ETDEWEB)
Berry, R. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2017-08-14
In the literature, the abundance of pipe network junction models, as well as inclusion of dissipative losses between connected pipes with loss coefficients, has been treated using the incompressible flow assumption of constant density. This approach is fundamentally, physically wrong for compressible flow with density change. This report introduces a mathematical modeling approach for general junctions in piping network systems for which the transient flows are compressible and single-phase. The junction could be as simple as a 1-pipe input and 1-pipe output with differing pipe cross-sectional areas for which a dissipative loss is necessary, or it could include an active component, between an inlet pipe and an outlet pipe, such as a pump or turbine. In this report, discussion will be limited to the former. A more general branching junction connecting an arbitrary number of pipes with transient, 1-D compressible single-phase flows is also presented. These models will be developed in a manner consistent with the use of a general equation of state like, for example, the recent Spline-Based Table Look-up method [1] for incorporating the IAPWS-95 formulation [2] to give accurate and efficient calculations for properties for water and steam with RELAP-7 [3].
Wu, Jibing; Meng, Qinggang; Deng, Su; Huang, Hongbin; Wu, Yahui; Badii, Atta
2017-01-01
Heterogeneous information networks (e.g. bibliographic networks and social media networks) that consist of multiple interconnected objects are ubiquitous. Clustering analysis is an effective method to understand the semantic information and interpretable structure of the heterogeneous information networks, and it has attracted the attention of many researchers in recent years. However, most studies assume that heterogeneous information networks usually follow some simple schemas, such as bi-typed networks or star network schema, and they can only cluster one type of object in the network each time. In this paper, a novel clustering framework is proposed based on sparse tensor factorization for heterogeneous information networks, which can cluster multiple types of objects simultaneously in a single pass without any network schema information. The types of objects and the relations between them in the heterogeneous information networks are modeled as a sparse tensor. The clustering issue is modeled as an optimization problem, which is similar to the well-known Tucker decomposition. Then, an Alternating Least Squares (ALS) algorithm and a feasible initialization method are proposed to solve the optimization problem. Based on the tensor factorization, we simultaneously partition different types of objects into different clusters. The experimental results on both synthetic and real-world datasets have demonstrated that our proposed clustering framework, STFClus, can model heterogeneous information networks efficiently and can outperform state-of-the-art clustering algorithms as a generally applicable single-pass clustering method for heterogeneous network which is network schema agnostic.
Directory of Open Access Journals (Sweden)
Kaibo Nie
2018-01-01
Full Text Available In this study, SiC nanoparticles were added into matrix alloy through a combination of semisolid stirring and ultrasonic vibration while dynamic precipitation of second phases was obtained through multi-pass forging with varying temperatures. During single-pass forging of the present composite, as the deformation temperature increased, the extent of recrystallization increased, and grains were refined due to the inhibition effect of the increasing amount of dispersed SiC nanoparticles. A small amount of twins within the SiC nanoparticle dense zone could be found while the precipitated phases of Mg17Al12 in long strips and deformation bands with high density dislocations were formed in the particle sparse zone after single-pass forging at 350 °C. This indicated that the particle sparse zone was mainly deformed by dislocation slip while the nanoparticle dense zone may have been deformed by twinning. The yield strength and ultimate tensile strength of the composites were gradually enhanced through increasing the single-pass forging temperature from 300 °C to 400 °C, which demonstrated that initial high forging temperature contributed to the improvement of the mechanical properties. During multi-pass forging with varying temperatures, the grain size of the composite was gradually decreased while the grain size distribution tended to be uniform with reducing the deformation temperature and extending the forging passes. In addition, the amount of precipitated second phases was significantly increased compared with that after multi-pass forging under a constant temperature. The improvement in the yield strength of the developed composite was related to grain refinement strengthening and Orowan strengthening resulting from synergistical effect of the externally applied SiC nanoparticles and internally precipitated second phases.
Study of charge exchanges of heavy ions passing through solids
International Nuclear Information System (INIS)
Baron, Eric.
1975-01-01
The charge state distributions of 1 to 6MeV/nucleon heavy ions (from oxygen to krypton) passing through thin targets of various materials (C, Cu, Ag, Au) are studied. The variation of the average charge state and of the charge state fractions as a function of the thickness of carbon targets ranging from zero to the equilibrium thickness is measured; this allows the calculation of effective cross-sections of the charge changing process. It is also shown that the lower the target atomic number, the higher the average charge state, which is explained by a decrease of the capture cross sections. Finally, a semi-empirical formula predicting the average charge state is proposed, as an extension of Betz's and Nikolaev and Dmitriev's formula [fr
Even distribution/dividing of single-phase fluids by symmetric bifurcation of flow channels
International Nuclear Information System (INIS)
Liu, Hong; Li, Peiwen
2013-01-01
Highlights: ► We addressed an issue of distributing a flow to a number of flow channels uniformly. ► The flow distribution is accomplished through bifurcation of channels. ► Some key parameters to the flow distribution uniformity have been identified. ► Flow uniformity was studied for several versions of flow distributor designs. ► A novel fluid packaging device of high efficiency was provided. -- Abstract: This study addresses a fundamental issue of distributing a single-phase fluid flow into a number of flow channels uniformly. A basic mechanism of flow distribution is accomplished through bifurcation of channels that symmetrically split one flow channel into two downstream channels. Applying the basic mechanism, cascades flow distributions are designed to split one flow into a large number of downstream flows uniformly. Some key parameters decisive to the flow distribution uniformity in such a system have been identified, and the flow distribution uniformity of air was studied for several versions of flow distributor designs using CFD analysis. The effect of the key parameters of the flow channel designs to the flow distribution uniformity was investigated. As an example of industrial application, a novel fluid packaging device of high efficiency was proposed and some CFD analysis results for the device were provided. The optimized flow distributor makes a very good uniform flow distribution which will significantly improve the efficiency of fluid packaging. The technology is expected to be of great significance to many industrial devices that require high uniformity of flow distribution
Development of flow-through and dip-stick immunoassays for screening of sulfonamide residues.
Zhang, Hongyan; Zhang, Yan; Wang, Shuo
2008-08-20
Two formats of membrane-based competitive enzyme immunoassays (flow-through and dip-stick) have been developed for the screening of sulfonamide residues in pig muscle and milk. Membrane was coated with anti-sulfonamide antibody and a sulfonamide hapten D2-horseradish peroxidase (HRP) conjugant was used as the labeled antigen for competitive assay of sulfonamides. Visual detection limits of the flow-through or dip-stick assay were 1-5 microg L(-1) or 1-10 microg L(-1) in buffer for seven sulfonamides, respectively. Assay validation was performed using samples spiked with single sulfonamide, spiked samples were tested using the developed strip assays and results were compared with those obtained by a validated high-performance liquid chromatograph (HPLC) method. Results showed that the two strip assays were correlated well with HPLC, respectively. With assay times of 5 min (flow-through) and 15 min (dip-stick), these rapid tests could offer simple, rapid and cost-effective on-site screening tools to detect sulfonamides in pig muscle (flow-through or dip-stick) or milk (only dip-stick).
Asymmetric and nonlinear pass-through of crude oil prices to gasoline and natural gas prices
International Nuclear Information System (INIS)
Atil, Ahmed; Lahiani, Amine; Nguyen, Duc Khuong
2014-01-01
In this article, we use the recently developed nonlinear autoregressive distributed lags (NARDL) model to examine the pass-through of crude oil prices into gasoline and natural gas prices. Our approach allows us to simultaneously test the short- and long-run nonlinearities through positive and negative partial sum decompositions of the predetermined explanatory variables. It also offers the possibility to quantify the respective responses of gasoline and natural gas prices to positive and negative oil price shocks from the asymmetric dynamic multipliers. The obtained results indicate that oil prices affect gasoline prices and natural gas prices in an asymmetric and nonlinear manner, but the price transmission mechanism is not the same. Important policy implications can be learned from the empirical findings. - Highlights: • The pass-through of crude oil prices into gasoline and natural gas prices is examined. • We use a NARDL model to test for the long-run and short-run asymmetric reactions. • Both gasoline and natural gas prices significantly adjust to changes in the price of oil. • Negative oil shocks have greater effects than positive oil shocks. • Policy implications are discussed
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
Computed Flow Through An Artificial Heart Valve
Rogers, Stewart E.; Kwak, Dochan; Kiris, Cetin; Chang, I-Dee
1994-01-01
Report discusses computations of blood flow through prosthetic tilting disk valve. Computational procedure developed in simulation used to design better artificial hearts and valves by reducing or eliminating following adverse flow characteristics: large pressure losses, which prevent hearts from working efficiently; separated and secondary flows, which causes clotting; and high turbulent shear stresses, which damages red blood cells. Report reiterates and expands upon part of NASA technical memorandum "Computed Flow Through an Artificial Heart and Valve" (ARC-12983). Also based partly on research described in "Numerical Simulation of Flow Through an Artificial Heart" (ARC-12478).
Neeley, W E; Wardlaw, S C; Yates, T; Hollingsworth, W G; Swinnen, M E
1976-02-01
We describe a high-performance colorimeter with an electronic bubble gate for use with miniaturized continuous-flow analyzers. The colorimeter has a flow-through cuvette with optically flat quartz windows that allows a bubbled stream to pass freely without any breakup or retention of bubbles. The fluid volume in the light path is only 1.8 mul. The electronic bubble gate selectively removes that portion of the photodector signal produced by the air bubbles passing through the flow cell and allows that portion of the signal attributable to the fluid segment to pass to the recorder. The colorimeter is easy to use, rugged, inexpensive, and requires minimal adjustments.
Are snakes particles or waves? Scattering of a limbless locomotor through a single slit
Qian, Feifei; Dai, Jin; Gong, Chaohui; Choset, Howie; Goldman, Daniel
Droplets on vertically vibrated fluid surfaces can walk and diffract through a single slit by a pilot wave hydrodynamic interaction [Couder, 2006; Bush, 2015]. Inspired by the correspondence between emergent macroscale dynamics and phenomena in quantum systems, we tested if robotic snakes, which resemble wave packets, behave emergently like particles or waves when interacting with an obstacle. In lab experiments and numerical simulations we measured how a multi-module snake-like robot swam through a single slit. We controlled the snake undulation gait as a fixed serpenoid traveling wave pattern with varying amplitude and initial phase, and we examined the snake trajectory as it swam through a slit with width d. Robot trajectories were straight before interaction with the slit, then exited at different scattering angle θ after the interaction due to a complex interaction of the body wave with the slit. For fixed amplitude and large d, the snake passed through the slit with minimal interaction and theta was ~ 0 . For sufficiently small d, θ was finite and bimodally distributed, depending on the initial phase. For intermediate d, θ was sensitive to initial phase, and the width of the distribution of θ increased with decreasing d.
Flow enhancement of water flow through silica slit pores with graphene-coated walls
DEFF Research Database (Denmark)
Zambrano, Harvey; Wagemann, Enrique; Oyarzua, Elton
features a unparalleled combination of high specific surface area, chemical stability, mechanical strength and flexibility. Recently, the wettability of water droplets on multilayer graphene sheets deposited on a silica substrate has been investigated. In this study, we investigate the role of graphene......Nanofluidic devices such as Lab-On-a-Chip often are designed to transport water solutions through hydrophilic nano-conduits. In these systems with narrow confinement, the viscous forces dominate the flow and as a result, the hydrodynamic friction drag is very high. Moreover, the drag and the amount...... of energy required for pumping a fluid are directly related. Therefore, it is desirable to explore drag reduction strategies in nanoconfined flows. Liquids are known to slip past non-wetting surfaces. Graphene is a single-atom-thick sheet of carbon atoms arranged in a hexagonal honeycomb lattice, which...
A note on Fenchel cuts for the single-node flow problem
DEFF Research Database (Denmark)
Klose, Andreas
The single-node flow problem, which is also known as the single-sink fixed-charge transportation problem, consists in finding a minimum cost flow from a number of nodes to a single sink. The flow cost comprise an amount proportional to the quantity shipped as well as a fixed charge. In this note......, some structural properties of Fenchel cutting planes for this problem are described. Such cuts might then be applied for solving, e.g., fixed-charge transportation problems and more general fixed-charge network flow problems....
Yue, J; She, C-Y; Williams, B P; Vance, J D; Acott, P E; Kawahara, T D
2009-04-01
With two cw single-mode Nd:YAG lasers at 1064 and 1319 nm and a periodically poled lithium niobate crystal, 11 mW of 2 kHz/100 ms bandwidth single-mode tunable 589 nm cw radiation has been detected using single-pass sum-frequency generation. The demonstrated conversion efficiency is approximately 3.2%[W(-1) cm(-1)]. This compact solid-state light source has been used in a solid-state-dye laser hybrid sodium fluorescence lidar transmitter to measure temperatures and winds in the upper atmosphere (80-105 km); it is being implemented into the transmitter of a mobile all-solid-state sodium temperature and wind lidar under construction.
Hydrodynamics of single- and two-phase flow in inclined rod arrays
International Nuclear Information System (INIS)
Ebeling-Koning, D.B.; Todreas, N.E.
1983-09-01
Required inputs for thermal-hydraulic codes are constitutive relations for fluid-solid flow resistance, in single-phase flow, and interfacial momentum exchange (relative phase motion), in two-phase flow. An inclined rod array air-water experiment was constructed to study the hydrodynamics of multidimensional porous medium flow in rod arrays. Velocities, pressures, and bubble distributions were measured in square rod arrays of P/d = 1.5, at 0, 30, 45, and 90 degree inclinations to the vertical flow direction. Constitutive models for single-phase flow resistance are reviewed, new comprehensive models developed, and an assessment with previously published and new data made. The principle of superimposing one-dimensional correlations proves successful for turbulent single-phase inclined flow. For bubbly two-phase incline flow a new flow separation phenomena was observed and modeled. A two-region liquid velocity model is developed to explain the experimentally observed phenomena. Fundamental data for bubbles rising in rod arrays were also taken
Survival and Passage of Juvenile Chinook Salmon and Steelhead Passing through Bonneville Dam, 2011
Energy Technology Data Exchange (ETDEWEB)
Ploskey, Gene R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Batten, G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cushing, Aaron W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kim, Jin A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Gary E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Skalski, J. R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Townsend, Richard L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Seaburg, Adam [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Weiland, Mark A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Woodley, Christa M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hughes, James S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, Thomas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carpenter, Scott M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deng, Zhiqun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Etherington, D. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fischer, Eric S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fu, Tao [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Greiner, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hennen, Matthew J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Martinez, Jayson J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mitchell, T. D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rayamajhi, Bishes [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zimmerman, Shon A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2013-02-15
Pacific Northwest National Laboratory (PNNL) and subcontractors conducted an acoustic-telemetry study of juvenile salmonid fish passage and survival at Bonneville Dam in 2011. The study was conducted to assess the readiness of the monitoring system for official compliance studies under the 2008 Biological Opinion and Fish Accords and to assess performance measures including route-specific fish passage proportions, travel times, and survival based upon a virtual/paired-release model. The study relied on releases of live Juvenile Salmon Acoustic Telemetry System tagged smolts in the Columbia River and used acoustic telemetry to evaluate the approach, passage, and survival of passing juvenile salmon using a virtual release, paired reference release survival model. This study supports the U.S. Army Corps of Engineers’ continual effort to improve conditions for juvenile anadromous fish passing through Columbia River dams.
Flow-throttling orifice nozzle
International Nuclear Information System (INIS)
Sletten, H.L.
1975-01-01
A series-parallel-flow type throttling apparatus to restrict coolant flow to certain fuel assemblies of a nuclear reactor is comprised of an axial extension nozzle of the fuel assembly. The nozzle has a series of concentric tubes with parallel-flow orifice holes in each tube. Flow passes from a high pressure plenum chamber outside the nozzle through the holes in each tube in series to the inside of the innermost tube where the coolant, having dissipated most of its pressure, flows axially to the fuel element. (U.S.)
SECOND ROUND EFFECTS AND PASS-THROUGH OF FOOD PRICES TO INFLATION IN KENYA
Directory of Open Access Journals (Sweden)
Roseline Nyakerario Misati
2015-07-01
Full Text Available In the recent past, the Kenyan economy experienced persistent inflationary pressures, partly attributed to food price spikes. However, the quantitative role of food prices in inflation is not well understood or formally empirically analyzed in Kenya yet food occupies a weight of 36 percent in the consumer price index and contributes a monthly average of over 40 percent to overall inflation. Based on monthly data covering the period 1997-2012, this paper attempts to fill this gap by examining the relationship between food prices and inflation. The study used gap models and Phillips curve approaches to estimate the passthrough effects of food prices to both overall inflation and non-food non-fuel inflation. Based on gap models, the results confirm presence of second round effects from food prices to inflation while estimations of the Phillips curve suggest a domestic food price pass-through of 0.49 to overall inflation and 0.38 to non-food non-fuel inflation. The world food prices pass-through to overall inflation and non-food non-fuel inflation are estimated at 0.09 and 0.08, respectively. Thus this paper recommends usage of headline inflation to estimate trend inflation, enhanced communication to mitigate second round effects and that while monetary policy is very critical in anchoring inflationary expectations, there is mutual gain from a supportive fiscal policy in addressing supply side shocks.
Kim, Bryan; Chen, Jeff; Kron, Tomas; Battista, Jerry
2010-11-01
Gated radiotherapy of lung lesions is particularly complex for helical tomotherapy, due to the simultaneous motions of its three subsystems (gantry, couch and collimator). We propose a new way to implement gating for helical tomotherapy, namely multi-pass respiratory gating. In this method, gating is achieved by delivering only the beam projections that occur within a respiratory gating window, while blocking the rest of the beam projections by fully closing all collimator leaves. Due to the continuous couch motion, the planned beam projections must be delivered over multiple passes of radiation deliveries. After each pass, the patient couch is reset to its starting position, and the treatment recommences at a different phase of tumour motion to 'fill in' the previously blocked beam projections. The gating process may be repeated until the plan dose is delivered (full gating), or halted after a certain number of passes, with the entire remaining dose delivered in a final pass without gating (partial gating). The feasibility of the full gating approach was first tested for sinusoidal target motion, through experimental measurements with film and computer simulation. The optimal gating parameters for full and partial gating methods were then determined for various fractionation schemes through computer simulation, using a patient respiratory waveform. For sinusoidal motion, the PTV dose deviations of -29 to 5% observed without gating were reduced to range from -1 to 3% for a single fraction, with a 4 pass full gating. For a patient waveform, partial gating required fewer passes than full gating for all fractionation schemes. For a single fraction, the maximum allowed residual motion was only 4 mm, requiring large numbers of passes for both full (12) and partial (7 + 1) gating methods. The number of required passes decreased significantly for 3 and 30 fractions, allowing residual motion up to 7 mm. Overall, the multi-pass gating technique was shown to be a promising
Energy Technology Data Exchange (ETDEWEB)
Kim, Bryan; Chen, Jeff; Battista, Jerry [London Regional Cancer Program, London Health Sciences Centre, London, ON (Canada); Kron, Tomas, E-mail: bryan.kim@lhsc.on.c [Peter MacCallum Cancer Center, Melbourne (Australia)
2010-11-21
Gated radiotherapy of lung lesions is particularly complex for helical tomotherapy, due to the simultaneous motions of its three subsystems (gantry, couch and collimator). We propose a new way to implement gating for helical tomotherapy, namely multi-pass respiratory gating. In this method, gating is achieved by delivering only the beam projections that occur within a respiratory gating window, while blocking the rest of the beam projections by fully closing all collimator leaves. Due to the continuous couch motion, the planned beam projections must be delivered over multiple passes of radiation deliveries. After each pass, the patient couch is reset to its starting position, and the treatment recommences at a different phase of tumour motion to 'fill in' the previously blocked beam projections. The gating process may be repeated until the plan dose is delivered (full gating), or halted after a certain number of passes, with the entire remaining dose delivered in a final pass without gating (partial gating). The feasibility of the full gating approach was first tested for sinusoidal target motion, through experimental measurements with film and computer simulation. The optimal gating parameters for full and partial gating methods were then determined for various fractionation schemes through computer simulation, using a patient respiratory waveform. For sinusoidal motion, the PTV dose deviations of -29 to 5% observed without gating were reduced to range from -1 to 3% for a single fraction, with a 4 pass full gating. For a patient waveform, partial gating required fewer passes than full gating for all fractionation schemes. For a single fraction, the maximum allowed residual motion was only 4 mm, requiring large numbers of passes for both full (12) and partial (7 + 1) gating methods. The number of required passes decreased significantly for 3 and 30 fractions, allowing residual motion up to 7 mm. Overall, the multi-pass gating technique was shown to be a
Pulsatile turbulent flow through pipe bends at high Dean and Womersley numbers
Kalpakli, Athanasia; Örlü, Ramis; Tillmark, Nils; Alfredsson, P. Henrik
2011-12-01
Turbulent pulsatile flows through pipe bends are prevalent in internal combustion engine components which consist of bent pipe sections and branching conduits. Nonetheless, most of the studies related to pulsatile flows in pipe bends focus on incompressible, low Womersley and low Dean number flows, primarily because they aim in modeling blood flow, while internal combustion engine related flows have mainly been addressed in terms of integral quantities and consist of single point measurements. The present study aims at bridging the gap between these two fields by means of time-resolved stereoscopic particle image velocimetry measurements in a pipe bend with conditions that are close to those encountered in exhaust manifolds. The time/phase-resolved three-dimensional cross-sectional flow-field 3 pipe diameters downstream the pipe bend is captured and the interplay between different secondary motions throughout a pulse cycle is discussed.
Pulsatile turbulent flow through pipe bends at high Dean and Womersley numbers
International Nuclear Information System (INIS)
Kalpakli, Athanasia; Örlü, Ramis; Tillmark, Nils; Alfredsson, P Henrik
2011-01-01
Turbulent pulsatile flows through pipe bends are prevalent in internal combustion engine components which consist of bent pipe sections and branching conduits. Nonetheless, most of the studies related to pulsatile flows in pipe bends focus on incompressible, low Womersley and low Dean number flows, primarily because they aim in modeling blood flow, while internal combustion engine related flows have mainly been addressed in terms of integral quantities and consist of single point measurements. The present study aims at bridging the gap between these two fields by means of time-resolved stereoscopic particle image velocimetry measurements in a pipe bend with conditions that are close to those encountered in exhaust manifolds. The time/phase-resolved three-dimensional cross-sectional flow-field 3 pipe diameters downstream the pipe bend is captured and the interplay between different secondary motions throughout a pulse cycle is discussed.
Jenke, Christoph; Pallejà Rubio, Jaume; Kibler, Sebastian; Häfner, Johannes; Richter, Martin; Kutter, Christoph
2017-04-03
With the combination of micropumps and flow sensors, highly accurate and secure closed-loop controlled micro dosing systems for liquids are possible. Implementing a single stroke based control mode with piezoelectrically driven micro diaphragm pumps can provide a solution for dosing of volumes down to nanoliters or variable average flow rates in the range of nL/min to μL/min. However, sensor technologies feature a yet undetermined accuracy for measuring highly pulsatile micropump flow. Two miniaturizable in-line sensor types providing electrical readout-differential pressure based flow sensors and thermal calorimetric flow sensors-are evaluated for their suitability of combining them with mircopumps. Single stroke based calibration of the sensors was carried out with a new method, comparing displacement volumes and sensor flow volumes. Limitations of accuracy and performance for single stroke based flow control are described. Results showed that besides particle robustness of sensors, controlling resistive and capacitive damping are key aspects for setting up reproducible and reliable liquid dosing systems. Depending on the required average flow or defined volume, dosing systems with an accuracy of better than 5% for the differential pressure based sensor and better than 6.5% for the thermal calorimeter were achieved.
Single- and two-phase flow characterization using optical fiber bragg gratings.
Baroncini, Virgínia H V; Martelli, Cicero; da Silva, Marco José; Morales, Rigoberto E M
2015-03-17
Single- and two-phase flow characterization using optical fiber Bragg gratings (FBGs) is presented. The sensor unit consists of the optical fiber Bragg grating positioned transversely to the flow and fixed in the pipe walls. The hydrodynamic pressure applied by the liquid or air/liquid flow to the optical fiber induces deformation that can be detected by the FBG. Given that the applied pressure is directly related to the mass flow, it is possible to establish a relationship using the grating resonance wavelength shift to determine the mass flow when the flow velocity is well known. For two phase flows of air and liquid, there is a significant change in the force applied to the fiber that accounts for the very distinct densities of these substances. As a consequence, the optical fiber deformation and the correspondent grating wavelength shift as a function of the flow will be very different for an air bubble or a liquid slug, allowing their detection as they flow through the pipe. A quasi-distributed sensing tool with 18 sensors evenly spread along the pipe is developed and characterized, making possible the characterization of the flow, as well as the tracking of the bubbles over a large section of the test bed. Results show good agreement with standard measurement methods and open up plenty of opportunities to both laboratory measurement tools and field applications.
Friedrich, Sarah; Wang, Tza-Huei
Pressure-driven flow in micron-sized diameter capillaries can be used to separate DNA molecules by size in a technique called Free Solution Hydrodynamic Separation. By coupling this technique with Cylindrical Illumination Confocal Spectroscopy, we have developed a highly sensitive and quantitative platform capable of separating DNA molecules by length over a large dynamic range (25 bp to 48 kbp) in a single run using only picoliters or femtograms of a DNA sample. The optical detection volume completely spans the capillary cross section, enabling highly efficient single molecule detection for enhanced sensitivity and quantification accuracy via single molecule counting. Because each DNA molecule generates its own fluorescent burst, these burst profiles can be further analyzed to individually characterize each DNA molecule's shape as it passes through the detection region. We exploit these burst profiles to visualize fluctuations in conformation under shear flow in microcapillaries, and utilizing combined mobility shift analysis, explore the complex relationship between molecular properties including length and conformation, hydrodynamic mobility, solution conditions including ion species and concentrations, and separation conditions including flow rate and capillary diameter.
Directory of Open Access Journals (Sweden)
Sugantharaj Gnanadurai Sam Stanley
2016-01-01
Full Text Available Solar air heating is a technology in which the solar energy from the sun is captured by an absorbing medium and used to heat the air flowing through the heater. In this study, thermal performance of a double pass solar air heater has been investigated experimentally at different conditions. The experiments were conducted with different inclinations of the collector, with and without wire mesh vertically fixed at the second pass in transverse direction and with different mass flow rates. The effect of air mass flow rate, wire mesh pitch and collector inclination on temperature rise and thermal efficiency have been studied. Results show that efficiency increases with mass flow rate. For the same mass flow rate, the thermal efficiency increases with the decrease in the wire mesh pitch. The maximum daily average efficiency of air heater was 79.8% at 0.025 kg/s mass flow rate, 10 cm wire mesh gap and 9º collector inclination facing south. The highest collector efficiency was observed in solar air heaters with 10 cm wire mesh gap.
Magma flow through elastic-walled dikes
Bokhove, Onno; Woods, A.W.; de Boer, A
2005-01-01
A convection–diffusion model for the averaged flow of a viscous, incompressible magma through an elastic medium is considered. The magma flows through a dike from a magma reservoir to the Earth’s surface; only changes in dike width and velocity over large vertical length scales relative to the
A First-Order One-Pass CPS Transformation
DEFF Research Database (Denmark)
Danvy, Olivier; Nielsen, Lasse Reichstein
2002-01-01
We present a new transformation of call-by-value lambdaterms into continuation-passing style (CPS). This transformation operates in one pass and is both compositional and first-order. Because it operates in one pass, it directly yields compact CPS programs that are comparable to what one would...... write by hand. Because it is compositional, it allows proofs by structural induction. Because it is first-order, reasoning about it does not require the use of a logical relation. This new CPS transformation connects two separate lines of research. It has already been used to state a new and simpler...... correctness proof of a direct-style transformation, and to develop a new and simpler CPS transformation of control-flow information....
Helium-air exchange flow through an opening with a partition
International Nuclear Information System (INIS)
Kang, Tae-il; Okamoto, Koji; Madarame, Haruki; Fumizawa, Motoo.
1993-01-01
The helium-air exchange flow through a small vertical opening with a partition was experimentally investigated. The vertical partition was aligned with the center line of the small opening to evaluate the effects of the multiple openings. The dimensionless exchange flow rates, i.e., Froude numbers, were experimentally obtained with several opening ratios (H 1 /D f ), i.e., the ratio of the height to the effective diameter of the opening. In the case of low opening ratios (H 1 /D f 1 /D f ≥ 0.75), the measured Froude numbers for the multiple openings were larger than those for the single opening, because the upward and downward flows were separated by the vertical partition. Based on the balance between the pressure losses in the openings and the driving force due to density difference, the exchange flow rate was calculated, and found to agree qualitatively with the measured Froude numbers. The effect of the upward and downward flow interaction at the exit of the opening was found to play an important role in the prediction of the Froude number. (author)
International Nuclear Information System (INIS)
Herbert, P.
1995-02-01
For various reasons, extra by-passes are installed in district heating networks to ensure a high flow temperature when the water circulation is insufficient. By 'extra by-pass' we here mean a connection between the distribution pipe and the return pipe. This study mainly deals with extra by-passes to prevent freezing. The estimation of the extra by-pass costs is based on the district heating rates. Our assumption is that an extra by-pass can be regarded as a substation in the district heating network, with regard to the demand for the water flow, heat and power. The reason is the difficulty to obtain available facts to estimate the real costs concerning extra by-passes. Therefore, the method can not claim that the information about the costs is exact but gives an indication of the size of them. The valves in an extra by-pass can be set more or less open. We assume that manual valves in extra by-passes are wide open. Thermostatic valves are, however, assumed to be adjusted in order to cause a very small water flow. 2 refs, 16 figs, 9 tabs, 6 appendices
Directory of Open Access Journals (Sweden)
Christoph Jenke
2017-04-01
Full Text Available With the combination of micropumps and flow sensors, highly accurate and secure closed-loop controlled micro dosing systems for liquids are possible. Implementing a single stroke based control mode with piezoelectrically driven micro diaphragm pumps can provide a solution for dosing of volumes down to nanoliters or variable average flow rates in the range of nL/min to μL/min. However, sensor technologies feature a yet undetermined accuracy for measuring highly pulsatile micropump flow. Two miniaturizable in-line sensor types providing electrical readout—differential pressure based flow sensors and thermal calorimetric flow sensors—are evaluated for their suitability of combining them with mircopumps. Single stroke based calibration of the sensors was carried out with a new method, comparing displacement volumes and sensor flow volumes. Limitations of accuracy and performance for single stroke based flow control are described. Results showed that besides particle robustness of sensors, controlling resistive and capacitive damping are key aspects for setting up reproducible and reliable liquid dosing systems. Depending on the required average flow or defined volume, dosing systems with an accuracy of better than 5% for the differential pressure based sensor and better than 6.5% for the thermal calorimeter were achieved.
A stratified percolation model for saturated and unsaturated flow through natural fractures
International Nuclear Information System (INIS)
Pyrak-Nolte, L.J.
1990-01-01
The geometry of the asperities of contact between the two surfaces of a fracture and of the adjacent void spaces determines fluid flow through a fracture and the mechanical deformation across a fracture. Heuristically we have developed a stratified continuum percolation model to describe this geometry based on a fractal construction that includes scale invariance and correlation of void apertures. Deformation under stress is analyzed using conservation of rock volume to correct for asperity interpenetration. Single phase flow is analyzed using a critical path along which the principal resistance is a result of laminar flow across the critical neck in this path. Results show that flow decreases with apparent aperture raised to a variable power greater than cubic, as is observed in flow experiments on natural fractures. For two phases, flow of the non-wetting phase is likewise governed by the critical neck along the critical path of largest aperture but flow of the wetting phase is governed by tortuosity. 17 refs., 10 figs
Kothari, Darshan; Ketwaroo, Gyanprakash; Freedman, Steven D; Sheth, Sunil G
2017-08-01
The aim of this study was to determine the effect of established risk factors on the outcome of secretin pancreatic function testing (sPFT) in patients undergoing work-up for suspected chronic pancreatitis. We completed a retrospective review of patients who underwent sPFT for suspected chronic pancreatitis over 20 years. We compared peak bicarbonate concentrations between groups and completed univariate and multivariate analyses to determine associations between risk factors and positive sPFT results (peak bicarbonate pancreatitis (RAP) and with local complications from acute pancreatitis (AP) (P ≤ 0.05). The bicarbonate concentration in patients with and without other risk factors such as tobacco use, alcohol use, and family history of pancreatitis was not significantly different. Female sex, a history of AP, and a history of RAP were associated with positive sPFT results on univariate analysis (P ≤ 0.05). On multivariate analysis, sex and RAP remained significant. Our study demonstrates that female sex, history of AP and RAP, and AP with local complications are associated with positive sPFT results or lower peak bicarbonate concentration. However, other risk factors do not impact the results of sPFT.
Behaviour of neutrons passing through the Bloch wall
International Nuclear Information System (INIS)
Schaerpf, O.
1976-01-01
In part I of the present paper the pertinent knowledge about Bloch walls is presented and developed insofar as it appears necessary for the experiments with neutrons, that is to say the direction of magnetization within the domains, the calculation of the variation of magnetization in the wall, the wall thickness, and the zigzag structure of the Bloch wall. In part II it is first clarified why the Bloch wall can be treated as a continuum problem. It shows that this is possible far away from Laue reflexes. For angles far away from Laure-reflex angles the interaction of the periodic structure of the magnetization can be described with the aid of an averaged magnetic flux density. The consequence of it is the possibility of treating the problem by means of a Schroedinger equation with continous interaction. This leads to a law of refraction. The question of the possibilities for explaining the intensity behavior is treated in part III. This part, from different aspects, describes the fact, which already was pointed out in Schaerpf, O., Vehoff, H., Schwink, Ch. 1973, that the spin of the neutrons in passing through the wall is partly taken along by the magnetization gradually rotating in the wall. (orig./WBU) [de
Hydroxyl tagging velocimetry in a supersonic flow over a cavity
International Nuclear Information System (INIS)
Pitz, Robert W.; Lahr, Michael D.; Douglas, Zachary W.; Wehrmeyer, Joseph A.; Hu Shengteng; Carter, Campbell D.; Hsu, Kuang-Yu; Lum, Chee; Koochesfahani, Manoochehr M.
2005-01-01
Hydroxyl tagging velocimetry (HTV) measurements of velocity were made in a Mach 2 (M 2) flow with a wall cavity. In the HTV method, ArF excimer laser (193 nm) beams pass through a humid gas and dissociate H2O into H + OH to form a tagging grid of OH molecules. In this study, a 7x7 grid of hydroxyl (OH) molecules is tracked by planar laser-induced fluorescence. The grid motion over a fixed time delay yields about 50 velocity vectors of the two-dimensional flow in the plane of the laser sheets. Velocity precision is limited by the error in finding the crossing location of the OH lines written by the excimer tag laser. With a signal-to-noise ratio of about 10 for the OH lines, the determination of the crossing location is expected to be accurate within ±0.1 pixels. Velocity precision within the freestream, where the turbulence is low, is consistent with this error. Instantaneous, single-shot measurements of two-dimensional flow patterns were made in the nonreacting M 2 flow with a wall cavity under low- and high-pressure conditions. The single-shot profiles were analyzed to yield mean and rms velocity profiles in the M 2 nonreacting flow
Logtenberg, Hella; Lopez-Martinez, Maria J; Feringa, Ben L; Browne, Wesley R; Verpoorte, Elisabeth
2011-06-21
An approach to control two-phase flow systems in a poly(dimethylsiloxane) (PDMS) microfluidic device using spatially selective surface modification is demonstrated. Side-by-side flows of ethanol : water solutions containing different polymers are used to selectively modify both sides of a channel by laminar flow patterning. Introduction of air pockets during modification allows for control over the length of the channel section that is modified. This approach makes it possible to achieve slug flow and side-by-side flow of water : 1-octanol simultaneously within the same PDMS channel, without the need of additional structural elements. A key finding is that conditioning of the PDMS channels with 1-octanol before polymer deposition is crucial to achieving stable side-by-side flows.
Simulations of fluid flow through porous media based on cellular automata and non-linear dynamics
Energy Technology Data Exchange (ETDEWEB)
Paulson, K V
1992-05-15
A study is being carried out to apply cellular automata and non-linear dynamics in the construction of efficient and accurate computer simulations of multiphase fluid flow through porous media, with the objective of application to reservoir modelling for hydrocarbon recovery. An algorithm based on Boolean operations has been developed which transforms a PC clone into a highly efficient vector processor capable of cellular automata simulation of single fluid flow through two-dimensional rock matrix models of varying porosities. Macroscopic flow patterns have been established through spatial and temporal averaging with no floating point operations. Permeabilities of the different models have been calculated. Hardware allows the algorithm to function on dual processors on a PC platform using a video recording and editing facility. Very encouraging results have been obtained. 4 figs.
Energy analysis and improvement potential of finned double-pass solar collector
International Nuclear Information System (INIS)
Fudholi, Ahmad; Sopian, Kamaruzzaman; Othman, Mohd Yusof; Ruslan, Mohd Hafidz; Bakhtyar, B.
2013-01-01
Highlights: • The developed steady state model predicting the thermal performance of double-pass solar collectors is presented. • The main objective of this paper is to analyze the energy and exergy of finned double-pass solar collector. • A new mathematical model, solution procedure, and test results are presented. • The thermal performances and improvement potential of the double-pass solar collectors are discussed. - Abstract: Steady state energy balance equations for the finned double-pass solar collector have been developed. These equations were solved using the matrix inversion method. The predicted results were in agreement with the results obtained from the experiments. The predictions and experiments were observed at the mass flow rate ranging between 0.03 kg/s and 0.1 kg/s, and solar radiation ranging between 400 W/m 2 and 800 W/m 2 . The effects of mass flow rates and solar radiation levels on energy efficiency, exergy efficiency and the improvement potential have been observed. The optimum energy efficiency is approximately 77%, which was observed at the mass flow rate of 0.09 kg/s. The optical efficiency of the finned double-pass solar collector is approximately 70–80%. The exergy efficiency is approximately 15–28% and improvement potential of 740–1070 W for a solar radiation of 425–790 W/m 2
Directory of Open Access Journals (Sweden)
Yuncheng Bu
2018-03-01
Full Text Available The multi-baseline synthetic aperture radar (SAR tomography (TomoSAR system is employed in such applications as disaster remote sensing, urban 3-D reconstruction, and forest carbon storage estimation. This is because of its 3-D imaging capability in a single-pass platform. However, a high 3-D resolution of TomoSAR is based on the premise that the channel imbalance and antenna phase center (APC position are precisely known. If this is not the case, the 3-D resolution performance will be seriously degraded. In this paper, a unified algorithm for channel imbalance and APC position calibration of a single-pass multi-baseline TomoSAR system is proposed. Based on the maximum likelihood method, as well as the least squares and the damped Newton method, we can calibrate the channel imbalance and APC position. The algorithm is suitable for near-field conditions, and no phase unwrapping operation is required. The effectiveness of the proposed algorithm has been verified by simulation and experimental results.
Clogging arches in grains, colloids, and pedestrians flowing through constrictions
Zuriguel, Iker
When a group of particles pass through a narrow orifice, the flow might become intermittent due to the development of clogs that obstruct the constriction. This effect has been observed in many different fields such as mining transport, microbial growing, crowd dynamics, colloids, granular and active matter. In this work we introduce a general framework in which research in some of such scenarios can be encompassed. In particular, we analyze the statistical properties of the bottleneck flow in different experiments and simulations: granular media within vibrated silos, colloids, a flock of sheep and pedestrian evacuations. We reveal a common phenomenology that allows us to rigorously define a transition to a clogged state. Using this definition we explore the main variables involved, which are then grouped into three generic parameters. In addition, we will present results of the geometrical characteristics that the clogging arches have which are related with their stability against perturbations. We experimentally analyse the temporal evolution of the arches evidencing important differences among the structures that are easily destroyed and those that seem to resist forever (longer than the temporal window employed in our measurements). Ministerio de Economía y Competitividad (Spanish Government). Project No. FIS2014-57325.
Fogel, Mark A; Li, Christine; Wilson, Felice; Pawlowski, Tom; Nicolson, Susan C; Montenegro, Lisa M; Berenstein, Laura Diaz; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Keller, Marc S; Harris, Matthew A; Whitehead, Kevin K; Clancy, Robert; Elci, Okan; Bethel, Jim; Vossough, Arastoo; Licht, Daniel J
2016-01-01
Objective Patients with single ventricle can develop aortic-to-pulmonary collaterals (APCs). Along with systemic-to-pulmonary artery shunts, these structures represent a direct pathway from systemic to pulmonary circulations, and may limit cerebral blood flow (CBF). This study investigated the relationship between CBF and APC flow on room air and in hypercarbia, which increases CBF in patients with single ventricle. Methods 106 consecutive patients with single ventricle underwent 118 cardiac magnetic resonance (CMR) scans in this cross-sectional study; 34 prior to bidirectional Glenn (BDG) (0.50±0.30 years old), 50 prior to Fontan (3.19±1.03 years old) and 34 3–9 months after Fontan (3.98±1.39 years old). Velocity mapping measured flows in the aorta, cavae and jugular veins. Analysis of variance (ANOVA) and multiple linear regression were used. Significance was p<0.05. Results A strong inverse correlation was noted between CBF and APC/shunt both on room air and with hypercarbia whether CBF was indexed to aortic flow or body surface area, independent of age, cardiopulmonary bypass time, Po2 and Pco2 (R=−0.67–−0.70 for all patients on room air, p<0.01 and R=−0.49–−0.90 in hypercarbia, p<0.01). Correlations were not different between surgical stages. CBF was lower, and APCs/shunt flow was higher prior to BDG than in other stages. Conclusions There is a strong inverse relationship between CBF and APC/shunt flow in patients with single ventricle throughout surgical reconstruction on room air and in hypercarbia independent of other factors. We speculate that APC/shunt flow may have a negative impact on cerebral development and neurodevelopmental outcome. Interventions on APC may modify CBF, holding out the prospect for improving neurodevelopmental trajectory. Trial Registration Number NCT02135081. PMID:26048877
Effect of passing vessels on a moored ship
Energy Technology Data Exchange (ETDEWEB)
Lean, G H; Price, W A
1977-11-01
The effect of passing vessels on a moored ship was investigated by a series of model tests carried out at the Hydraulics Research Station for the Esso Petroleum Co. Ltd., transportation department in connection with their oil jetty at Milford Haven. A main conclusion was that the forces appeared to be due to the pressure gradients associated with the pattern of flow that accompanies the passing ship rather than with the wave system. Slack lines are to be avoided, and some relief in maximum line loads can be achieved by increasing the pretension. The results included the effects of passing vessel speed and ship clearance and draft.
FDM Analysis for Blood Flow through Stenosed Tapered Arteries
Directory of Open Access Journals (Sweden)
Sankar DS
2010-01-01
Full Text Available Abstract A computational model is developed to analyze the unsteady flow of blood through stenosed tapered narrow arteries, treating blood as a two-fluid model with the suspension of all the erythrocytes in the core region as Herschel-Bulkley fluid and the plasma in the peripheral layer as Newtonian fluid. The finite difference method is employed to solve the resulting system of nonlinear partial differential equations. The effects of stenosis height, peripheral layer thickness, yield stress, viscosity ratio, angle of tapering and power law index on the velocity, wall shear stress, flow rate and the longitudinal impedance are analyzed. It is found that the velocity and flow rate increase with the increase of the peripheral layer thickness and decrease with the increase of the angle of tapering and depth of the stenosis. It is observed that the flow rate decreases nonlinearly with the increase of the viscosity ratio and yield stress. The estimates of the increase in the longitudinal impedance to flow are considerably lower for the two-fluid Herschel-Bulkley model compared with those of the single-fluid Herschel-Bulkley model. Hence, it is concluded that the presence of the peripheral layer helps in the functioning of the diseased arterial system.
Energy Technology Data Exchange (ETDEWEB)
Zaitseva, E. V.; Markelov, A. S.; Trushin, V. N., E-mail: trushin@phys.unn.ru; Chuprunov, E. V. [Nizhni Novgorod State University (Russian Federation)
2013-12-15
The features of formation of thermal fields in potassium dihydrophosphate crystal doped with potassium permanganate under a 532-nm laser beam passing through it have been investigated. Data on the influence of birefringence on the temperature distribution in an anisotropic crystal whose surface is illuminated by a spatially modulated light beam are presented.
Jung, Seung-Ryoung; Han, Rui; Sun, Wei; Jiang, Yifei; Fujimoto, Bryant S; Yu, Jiangbo; Kuo, Chun-Ting; Rong, Yu; Zhou, Xing-Hua; Chiu, Daniel T
2018-05-15
We describe here a flow platform for quantifying the number of biomolecules on individual fluorescent nanoparticles. The platform combines line-confocal fluorescence detection with near nanoscale channels (1-2 μm in width and height) to achieve high single-molecule detection sensitivity and throughput. The number of biomolecules present on each nanoparticle was determined by deconvolving the fluorescence intensity distribution of single-nanoparticle-biomolecule complexes with the intensity distribution of single biomolecules. We demonstrate this approach by quantifying the number of streptavidins on individual semiconducting polymer dots (Pdots); streptavidin was rendered fluorescent using biotin-Alexa647. This flow platform has high-throughput (hundreds to thousands of nanoparticles detected per second) and requires minute amounts of sample (∼5 μL at a dilute concentration of 10 pM). This measurement method is an additional tool for characterizing synthetic or biological nanoparticles.
Investigation on the Flow in a Rotor-Stator Cavity with Centripetal Through-Flow
Directory of Open Access Journals (Sweden)
Bo Hu
2017-10-01
Full Text Available Daily and Nece distinguished four flow regimes in an enclosed rotor-stator cavity, which are dependent on the circumferential Reynolds number and dimensionless axial gap width. A diagram of the different flow regimes including the respective mean profiles for both tangential and radial velocity was developed. The coefficients for the different flow regimes have also been correlated. In centrifugal pumps and turbines, the centripetal through-flow is quite common from the outer radius of the impeller to the impeller eye, which has a strong influence on the radial pressure distribution, axial thrust and frictional torque. The influence of the centripetal through-flow on the cavity flow with different circumferential Reynolds numbers and dimensionless axial gap width is not sufficiently investigated. It is also quite important to convert the 2D Daily and Nece diagram into 3D by introducing the through-flow coefficient. In order to investigate the impact of the centripetal through-flow, a test rig is designed and built up at the University of Duisburg-Essen. The design of the test rig is described. The impact of the above mentioned parameters on the velocity profile, pressure distribution, axial thrust and frictional torque are presented and analyzed in this paper. The 3D Daily and Nece diagram introducing the through-flow coefficient is also organized in this paper.
Energy Technology Data Exchange (ETDEWEB)
Sadeghi-Goughari, Moslem [Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Hosseini, Mohammad [Sirjan University of Technology, Sirjan (Iran, Islamic Republic of)
2015-02-15
The vibrational behavior of a viscous nanoflow-conveying single-walled carbon nanotube (SWCNT) was investigated. The nonuniformity of the flow velocity distribution caused by the viscosity of fluid and the small-size effects on the flow field was considered. Euler-Bernoulli beam model was used to investigate flow-induced vibration of the nanotube, while the non-uniformity of the flow velocity and the small-size effects of the flow field were formulated through Knudsen number (Kn), as a discriminant parameter. For laminar flow in a circular nanotube, the momentum correction factor was developed as a function of Kn. For Kn = 0 (continuum flow), the momentum correction factor was found to be 1.33, which decreases by the increase in Kn may even reach near 1 for the transition flow regime. We observed that for passage of viscous flow through a nanotube with the non-uniform flow velocity, the critical continuum flow velocity for divergence decreased considerably as opposed to those for the uniform flow velocity, while by increasing Kn, the difference between the uniform and non-uniform flow models may be reduced. In the solution part, the differential transformation method (DTM) was used to solve the governing differential equations of motion.
International Nuclear Information System (INIS)
Sadeghi-Goughari, Moslem; Hosseini, Mohammad
2015-01-01
The vibrational behavior of a viscous nanoflow-conveying single-walled carbon nanotube (SWCNT) was investigated. The nonuniformity of the flow velocity distribution caused by the viscosity of fluid and the small-size effects on the flow field was considered. Euler-Bernoulli beam model was used to investigate flow-induced vibration of the nanotube, while the non-uniformity of the flow velocity and the small-size effects of the flow field were formulated through Knudsen number (Kn), as a discriminant parameter. For laminar flow in a circular nanotube, the momentum correction factor was developed as a function of Kn. For Kn = 0 (continuum flow), the momentum correction factor was found to be 1.33, which decreases by the increase in Kn may even reach near 1 for the transition flow regime. We observed that for passage of viscous flow through a nanotube with the non-uniform flow velocity, the critical continuum flow velocity for divergence decreased considerably as opposed to those for the uniform flow velocity, while by increasing Kn, the difference between the uniform and non-uniform flow models may be reduced. In the solution part, the differential transformation method (DTM) was used to solve the governing differential equations of motion.
The Dissolution Behavior of Borosilicate Glasses in Far-From Equilibrium Conditions
Energy Technology Data Exchange (ETDEWEB)
Neeway, James J.; Rieke, Peter C.; Parruzot, Benjamin PG; Ryan, Joseph V.; Asmussen, Robert M.
2018-02-10
In far-from-equilibrium conditions, the dissolution of borosilicate glasses used to immobilize nuclear waste is known to be a function of both temperature and pH. The aim of this paper is to study effects of these variables on three model waste glasses (SON68, ISG, AFCI). To do this, experiments were conducted at temperatures of 23, 40, 70, and 90 °C and pH(RT) values of 9, 10, 11, and 12 with the single-pass flow-through (SPFT) test method. The results from these tests were then used to parameterize a kinetic rate model based on transition state theory. Both the absolute dissolution rates and the rate model parameters are compared with previous results. Discrepancies in the absolute dissolution rates as compared to those obtained using other test methods are discussed. Rate model parameters for the three glasses studied here are nearly equivalent within error and in relative agreement with previous studies. The results were analyzed with a linear multivariate regression (LMR) and a nonlinear multivariate regression performed with the use of the Glass Corrosion Modeling Tool (GCMT), which is capable of providing a robust uncertainty analysis. This robust analysis highlights the high degree of correlation of various parameters in the kinetic rate model. As more data are obtained on borosilicate glasses with varying compositions, the effect of glass composition on the rate parameter values could possibly be obtained. This would allow for the possibility of predicting the forward dissolution rate of glass based solely on composition
DURABILITY TESTING OF FLUIDIZED BED STEAM REFORMER (FBSR) WASTE FORMS
International Nuclear Information System (INIS)
Jantzen, C
2006-01-01
Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of high sodium aqueous radioactive wastes. The addition of clay and a catalyst as co-reactants converts high sodium aqueous low activity wastes (LAW) such as those existing at the Hanford and Idaho DOE sites to a granular ''mineralized'' waste form that may be made into a monolith form if necessary. Simulant Hanford and Idaho high sodium wastes were processed in a pilot scale FBSR at Science Applications International Corporation (SAIC) Science and Technology Applications Research (STAR) facility in Idaho Falls, ID. Granular mineral waste forms were made from (1) a basic Hanford Envelope A low-activity waste (LAW) simulant and (2) an acidic INL simulant commonly referred to as sodium-bearing waste (SBW). The FBSR waste forms were characterized and the durability tested via ASTM C1285 (Product Consistency Test), the Environmental Protection Agency (EPA) Toxic Characteristic Leaching Procedure (TCLP), and the Single Pass Flow Through (SPFT) test. The durability of the FBSR waste form products was tested in order to compare the measured durability to previous FBSR waste form testing on Hanford Envelope C waste forms that were made by THOR Treatment Technologies (TTT) and to compare the FBSR durability to vitreous LAW waste forms, specifically the Hanford low activity waste (LAW) glass known as the Low-activity Reference Material (LRM). The durability of the FBSR waste form is comparable to that of the LRM glass for the test responses studied
Directory of Open Access Journals (Sweden)
Chu V. Nguyen
2017-04-01
Full Text Available This study utilizes an Autoregressive Distributed Lag model to investigate the nature of crude oil futures price pass-through since 2006. The empirical results reveal a very high but incomplete short-run pass-through rate from the crude oil futures price to the gasoline futures price of 0.849298 with a corresponding negative long-run pass-through rate of -0.2440894. These empirical findings suggest that traders in the U.S. oil and gasoline futures markets overreact to fluctuations in the crude oil futures price as evidenced by subsequent corrections made over the sample period. The result of the bounds test for a long-term relationship between these two futures prices is inconclusive. The empirical findings further suggest that U.S. futures market traders considered futures prices of gasoline three weeks earlier in determining the current trading price while taking only one week to respond completely to the shock in the crude oil futures price. The empirical findings of this investigation may address the core elements of the price dynamics of the crude oil and gasoline futures markets and advance inquiry into assessment tools that could manage a very complex market challenge, especially for policy makers in countries with transitional economies in Eastern Europe, Caucasus and Central Asia.
International Nuclear Information System (INIS)
2016-05-01
This report provides a Peer review of the study 'Ex-post Investigation of Cost Pass- Though in the EU ETS: an analysis of six sectors' produced by CE-Delft and Oeko Institut and published by the EU Commission in November 2015. The study of CE-Delft and Oeko Institut (2015) investigates carbon costs pass-through across iron and steel, refineries, cement, organic basic chemicals, fertilizer, and glass. It also provides estimates of these cost pass-through rates of roughly around 100% for petrochemicals, 80-100% for petrol above 100% for diesel and gas-oil. Our Peer review (on refineries and organic basic chemicals) concludes that the results of the study cannot be used as direct policy recommendations due to the following three main limitations. The robustness of the econometric results is not clearly grounded: the claims of the study are only supported at a low confidence level (the chosen confidence interval was 10% while sound econometric practice would require at least 5%). Moreover detailed analysis shows that the hypothesis of a cost pass-through is significant (at 10%) only for some products and for some EU countries. The results are heterogeneous and not representative of a conclusion at the EU level for either sector. The quantitative estimates on the cost pass-through rates are obtained through a simple accounting relationship between input costs and output prices. Economic practice would rather use an explicit price formation model allowing for such factors as trade intensity, market structure and concentration, heterogeneity of competitors, etc... Some of these factors are marginally analyzed in the study without providing clear conclusions. Indeed, without any in-depth statistical analysis, the study cannot establish a statistical significant relationship between market shares and cost pass-through rates. Other explanatory variables such as the role of EUA price volatility and the macro-economic environment should also have been considered
Brazed thermocouple pass-through for sodium service in a liquid-metal-cooled fast breeder reactor
International Nuclear Information System (INIS)
Walker, D.E.
1975-10-01
Sensors installed in special fuel elements for the EBR-II reactor had 30-ft-long leads that would pass from the sodium environment through a sealed bulkhead. A hydrogen-atmosphere, induction-heated brazing furnace was constructed to simultaneously braze 20-26 separate sensor leads at one time. The brazed seals were leak-tight, and the sheath wall has less than 10 percent interaction with the braze alloy
Turbulence generation through intense kinetic energy sources
Maqui, Agustin F.; Donzis, Diego A.
2016-06-01
Direct numerical simulations (DNS) are used to systematically study the development and establishment of turbulence when the flow is initialized with concentrated regions of intense kinetic energy. This resembles both active and passive grids which have been extensively used to generate and study turbulence in laboratories at different Reynolds numbers and with different characteristics, such as the degree of isotropy and homogeneity. A large DNS database was generated covering a wide range of initial conditions with a focus on perturbations with some directional preference, a condition found in active jet grids and passive grids passed through a contraction as well as a new type of active grid inspired by the experimental use of lasers to photo-excite the molecules that comprise the fluid. The DNS database is used to assert under what conditions the flow becomes turbulent and if so, the time required for this to occur. We identify a natural time scale of the problem which indicates the onset of turbulence and a single Reynolds number based exclusively on initial conditions which controls the evolution of the flow. It is found that a minimum Reynolds number is needed for the flow to evolve towards fully developed turbulence. An extensive analysis of single and two point statistics, velocity as well as spectral dynamics and anisotropy measures is presented to characterize the evolution of the flow towards realistic turbulence.
International Nuclear Information System (INIS)
Glass, R.J.; Tidwell, V.C.
1991-01-01
As part of the Yucca Mountain Project, our research program to develop and validate conceptual models for flow and transport through unsaturated fractured rock integrates fundamental physical experimentation with conceptual model formulation and mathematical modeling. Our research is directed toward developing and validating macroscopic, continuum-based models and supporting effective property models because of their widespread utility within the context of this project. Success relative to the development and validation of effective property models is predicated on a firm understanding of the basic physics governing flow through fractured media, specifically in the areas of unsaturated flow and transport in a single fracture and fracture-matrix interaction. 43 refs
International Nuclear Information System (INIS)
Glass, R.J.; Tidwell, V.C.
1991-09-01
As part of the Yucca Mountain Project, our research program to develop and validate conceptual models for flow and transport through unsaturated fractured rock integrates fundamental physical experimentation with conceptual model formulation and mathematical modeling. Our research is directed toward developing and validating macroscopic, continuum-based models and supporting effective property models because of their widespread utility within the context of this project. Success relative to the development and validation of effective property models is predicted on a firm understanding of the basic physics governing flow through fractured media, specifically in the areas of unsaturated flow and transport in a single fracture and fracture-matrix interaction
International Nuclear Information System (INIS)
Glass, R.J.; Tidwell, V.C.
1991-01-01
As part of the Yucca Mountain Project, our research program to develop and validate conceptual models for flow and transport through unsaturated fractured rock integrates fundamental physical experimentation with conceptual model formulation and mathematical modeling. Our research is directed toward developing and validating macroscopic, continuum-based models and supporting effective property models because of their widespread utility within the context of this project. Success relative to the development and validation of effective property models is predicted on a firm understanding of the basic physics governing flow through fractured media, specifically in the areas of unsaturated flow and transport in a single fracture and fracture-matrix interaction
International Nuclear Information System (INIS)
Monir, C.
1991-02-01
A two-dimensional procedure, VANTACY-II, describing the turbulent velocity and temperature fields for single phase flow in tight lattices is presented and validated. The flow is assumed to be steady, incrompressible and hydraulic and thermal fully developed. First, the state of art of turbulent momentum and heat transport in tight lattices is documented. It is shown that there is a necessity for experimental investigations in the field of turbulent heat transport. The presented new procedure is based on the turbulence model VELASCO-TUBS by NEELEN. The numerical solution of the balance equations is done by the finite element method code VANTACY by KAISER. The validation of the new procedure VANTACY-II is done by comparing the numerically calculated data for the velocity and temperature fields and for natural mixing with the experimental data of SEALE. The comparison shows a good agreement of experimental and numerically computed data. The observed differences can be mainly attributed to the model of the turbulent PRANDTL number used in the new procedure. (orig.) [de
Stationary velocity distributions in traffic flows
International Nuclear Information System (INIS)
1997-01-01
We introduce a traffic flow model that incorporates clustering and passing. We obtain analytically the steady state characteristics of the flow from a Boltzmann-like equation. A single dimensionless parameter, R=c 0 v 0 t 0 with c 0 the concentration, v 0 the velocity range, and t 0 -1 the passing rate, determines the nature of the steady state. When R 1, large clusters with average mass left-angle m right-angle ∼R α form, and the flux is J∼R -γ . The initial distribution of slow cars governs the statistics. When P 0 (v)∼v μ as v→0, the scaling exponents are γ=1/(μ+2), α=1/2 when μ>0, and α=(μ+1)/(μ+2) when μ<0. copyright 1997 The American Physical Society
Steam exit flow design for aft cavities of an airfoil
Storey, James Michael; Tesh, Stephen William
2002-01-01
Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.
Numerical Simulation of single-stage axial fan operation under dusty flow conditions
Minkov, L. L.; Pikushchak, E. V.
2017-11-01
Assessment of the aerodynamic efficiency of the single-stage axial flow fan under dusty flow conditions based on a numerical simulation using the computational package Ansys-Fluent is proposed. The influence of dust volume fraction on the dependences of the air volume flow rate and the pressure drop on the rotational speed of rotor is demonstrated. Matching functions for formulas describing a pressure drop and volume flow rate in dependence on the rotor speed and dust content are obtained by numerical simulation for the single-stage axial fan. It is shown that the aerodynamic efficiency of the single-stage axial flow fan decreases exponentially with increasing volume content of dust in the air.
Inflation environment and lower exchange rate pass-through in Brazil: is there a relationship?
Directory of Open Access Journals (Sweden)
Reginaldo Pinto Nogueira Junior
2010-03-01
Full Text Available Recent studies have suggested that the shift from a high to a low inflation environment induces a decline in the degree of exchange rate pass-through (ERPT into prices. In this paper we present empirical evidence on this matter for Brazil, applying a smooth transition regression model and testing lagged inflation as a potential transition variable. The results presented in this paper go in line with the literature, and suggest that the lower ERPT largely documented for Brazil in recent years may also be a corollary of low and stable inflation.A literatura recente sugere que a transição de um regime de alta para baixa inflação induz uma redução no pass-through cambial (ERPT. Neste artigo apresentamos evidência empírica sobre essa questão, utilizando um modelo não-linear com smooth transition, e testando defasagens da taxa de inflação como variável de transição. Os resultados encontrados corroboram com a literatura sobre o tema, sugerindo que a redução de ERPT amplamente documentada para o Brasil em períodos recentes pode ser também uma conseqüência de taxas mais baixas e estáveis de inflação.
Effect of a ballast zone on the hydraulic stability of a single-pass steam generator
International Nuclear Information System (INIS)
Belyakov, I.I.; Kvetnyj, M.A.; Loginov, D.A.
1985-01-01
A new mechanism of hydraulic instability of boiling channels with convection heating which reveals in the presence of a developed ballast zone at decreased loads of a counterflan steam generator operation is considered. It is shown that for the certain combinations of thermal and technical parameters pulsation regimes caused by the ballast zone displacement over the heating surface are possible. The parameter relation at which the ballast zone position becomes unstable is obtained. The effect of the ballast zone on the statis steam generator stability is established. A mechanism of whole-circuit pulsations revealed when developing start regimes of single-pass steam generator heated with liquid sodium is explained from the positions of the instability
Reddy, Kavitha K; Brauer, Jeremy A; Anolik, Robert; Bernstein, Leonard; Brightman, Lori; Hale, Elizabeth; Karen, Julie; Weiss, Elliot; Geronemus, Roy G
2013-02-01
Laser tattoo removal using multiple passes per session, with each pass delivered after spontaneous resolution of whitening, improves tattoo fading in a 60-minute treatment time. Our objective was to evaluate the safety and efficacy of topical perfluorodecalin (PFD) in facilitating rapid effective multiple-pass tattoo removal. In a randomized, controlled study using Q-switched ruby or Nd:YAG laser, 22 previously treated tattoos were treated with 3 passes using PFD to resolve whitening after each pass ("R0 method"). In previously untreated symmetric tattoos, seven were treated over half of the tattoo with the R20 method, and the opposite half with 4 passes using PFD (R0 method); two were treated over half with a single pass and the opposite half with 4 passes using PFD (R0 method); and six treated over half with a single pass followed by PFD and the opposite half with a single pass alone. Blinded dermatologists rated tattoo fading at 1-3 months. Optical coherence tomography (OCT) imaging of whitening was performed in two tattoos. Topical PFD clinically resolved immediate whitening reactions within a mean 5 seconds (range 3-10 seconds). Tattoos treated with the R0 method demonstrated excellent fading in an average total treatment time of 5 minutes. Tattoo areas treated with the R0 method demonstrated equal fading compared to the R20 method, and improved fading compared to a single pass method. OCT imaging of whitening demonstrated epidermal and dermal hyper-reflective "bubbles" that dissipated until absent at 9-10 minutes after PFD application, and at 20 minutes without intervention. Multiple-pass tattoo removal using PFD to deliver rapid sequential passes (R0 method) appears equally effective as the R20 method, in a total treatment time averaging 5 minutes, and more effective than single pass treatment. OCT-visualized whitening-associated "bubbles," upon treatment with PFD, resolve twice as rapidly as spontaneous resolution. Copyright © 2012 Wiley
Boundary control of fluid flow through porous media
DEFF Research Database (Denmark)
Hasan, Agus; Foss, Bjarne; Sagatun, Svein Ivar
2010-01-01
The flow of fluids through porous media can be described by the Boussinesq’s equation with mixed boundary conditions; a Neumann’s boundary condition and a nonlinear boundary condition. The nonlinear boundary condition provides a means to control the fluid flow through porous media. In this paper,......, some stabilizing controllers are constructed for various cases using Lyapunov design.......The flow of fluids through porous media can be described by the Boussinesq’s equation with mixed boundary conditions; a Neumann’s boundary condition and a nonlinear boundary condition. The nonlinear boundary condition provides a means to control the fluid flow through porous media. In this paper...
Mechanisms of temporal variation in single-nephron blood flow in rats
DEFF Research Database (Denmark)
Yip, K P; Holstein-Rathlou, N H; Marsh, D J
1993-01-01
Modified laser-Doppler velocimetry was used to determine the number of different mechanisms regulating single-nephron blood flow. Two oscillations were identified in star vessel blood flow, one at 20-50 mHz and another at 100-200 mHz. Tubuloglomerular feedback (TGF) mediates the slower oscillation......, and the faster one is probably myogenic in origin. Acute hypertension increased autospectral power in the 20-50 mHz and 100-200 mHz frequency bands to 282 +/- 50 and 248 +/- 64%, respectively, of control even though mean single-nephron blood flow was autoregulated. Mean blood flow increased 24.6 +/- 6.1% when...... components in efferent arteriole blood flow....
Directory of Open Access Journals (Sweden)
Teresa S. López
2012-12-01
Full Text Available This paper investigates exchange rate pass-through inflation, and the wage bargaining process, in a developing economy in which firms' market power is largely dependent on technical progress embodied in imported intermediates and capital goods. It develops a heterodox model of income distribution, based on theoretical contributions from Latin American structuralists, labor market segmentationists and post-Keynesian writers, and it presents supportive empirical evidence from the Mexican economy.
Water transport and desalination through double-layer graphyne membranes.
Akhavan, Mojdeh; Schofield, Jeremy; Jalili, Seifollah
2018-05-16
Non-equilibrium molecular dynamics simulations of water-salt solutions driven through single and double-layer graphyne membranes by a pressure difference created by rigid pistons are carried out to determine the relative performance of the membranes as filters in a reverse osmosis desalination process. It is found that the flow rate of water through a graphyne-4 membrane is twice that of a graphyne-3 membrane for both single and double-layer membranes. Although the addition of a second layer to a single-layer membrane reduces the membrane permeability, the double-layer graphyne membranes are still two or three orders of magnitude more permeable than commercial reverse osmosis membranes. The minimum reduction in flow rate for double-layer membranes occurs at a layer spacing of 0.35 nm with an AA stacking configuration, while at a spacing of 0.6 nm the flow rate is close to zero due to a high free energy barrier for permeation. This is caused by the difference in the environments on either side of the membrane sheets and the formation of a compact two-dimensional layer of water molecules in the interlayer space which slows down water permeation. The distribution of residence times of water molecules in the interlayer region suggests that at the critical layer spacing of 0.6 nm, a cross-over occurs in the mechanism of water flow from the collective movement of hydrogen-bonded water sheets to the permeation of individual water molecules. All membranes are demonstrated to have a high salt rejection fraction and the double-layered graphyne-4 membranes can further increase the salt rejection by trapping ions that have passed through the first membrane from the feed solution in the interlayer space.
Experimental study on local resistance of two-phase flow through spacer grid with rod bundle
International Nuclear Information System (INIS)
Yan Chaoxing; Yan Changqi; Sun Licheng; Tian Qiwei
2015-01-01
The experimental study on local resistance of single-phase and two-phase flows through a spacer grid in a vertical channel with 3 × 3 rod bundle was carried out under the normal temperature and pressure. For the case of single-phase flow, the liquid Reynolds number covered the range of 290-18 007. For the case of two-phase flow, the ranges of gas and liquid superficial velocities were 0.013-3.763 m/s and 0.076-1.792 m/s, respectively. A correlation for predicting local resistance of single-phase flow was given based on experimental results. Eight classical two-phase viscosity formulae for homogeneous model were evaluated against the experimental data of two-phase flow. The results show that Dukler model predicts the experimental data well in the range of Re 1 < 9000 while McAdams correlation is the best one for Re 1 ≥ 9000. For all experimental data, Dukler model provides the best prediction with the mean relative error of 29.03%. A new correlation is fitted for the range of Re 1 < 9000 by considering mass quality, two- phase Reynolds number and liquid and gas densities, resulting in a good agreement with the experimental data. (authors)
Directory of Open Access Journals (Sweden)
V. I. Nazarov
2013-01-01
Full Text Available The paper describes technical and economic evaluation of various methods pertaining to passing through failures of electric load at TPP which is operating in accordance with heating schedule.
Energy Technology Data Exchange (ETDEWEB)
Meyler, Aidan [European Central Bank, Frankfurt am Main (Germany)
2009-11-15
Crude and refined oil prices have been relatively high and volatile on a sustained basis since 1999. This paper considers the pass through of oil prices into consumer liquid (i.e. petrol, diesel and heating) fuel prices in such an environment. The pass through of oil prices into consumer liquid fuel prices has already been addressed extensively in the literature. Nonetheless much of this literature has either focused on the United States or on a time period when oil prices were relatively stable, or has used monthly data. The main contribution of this paper is a comprehensive combination of many features that have been considered before but rarely jointly. These features include: (1) the analysis of the euro area as an aggregate and a large number of countries (the initial 12 member states); (2) the consideration of different time periods; (3) the modelling of the data in raw levels rather than in log levels. This turns out to have important implications for our findings; (4) the use of high frequency (weekly) data, which, as results will suggest, are the lowest frequency one should consider; (5) the investigation of the different stages of the production chain from crude oil prices to retail distribution - refining costs and margins, distribution and retailing costs and margins; (6) the examination of prices including and excluding taxes - excise and value-added; (7) the modelling of prices for three fuel types - passenger car petrol and diesel separately and home heating fuel oil; (8) lastly we also address the issue of possible asymmetries, allowing for the pass through to vary according to (a) whether price are increasing or decreasing and (b) whether price levels are above or below their equilibrium level. The main findings are as follows: First, as distribution and retailing costs and margins have been broadly stable on average, the modelling of the relationship between consumer prices excluding taxes and upstream prices in raw levels rather than in
International Nuclear Information System (INIS)
Meyler, Aidan
2009-01-01
Crude and refined oil prices have been relatively high and volatile on a sustained basis since 1999. This paper considers the pass through of oil prices into consumer liquid (i.e. petrol, diesel and heating) fuel prices in such an environment. The pass through of oil prices into consumer liquid fuel prices has already been addressed extensively in the literature. Nonetheless much of this literature has either focused on the United States or on a time period when oil prices were relatively stable, or has used monthly data. The main contribution of this paper is a comprehensive combination of many features that have been considered before but rarely jointly. These features include: (1) the analysis of the euro area as an aggregate and a large number of countries (the initial 12 member states); (2) the consideration of different time periods; (3) the modelling of the data in raw levels rather than in log levels. This turns out to have important implications for our findings; (4) the use of high frequency (weekly) data, which, as results will suggest, are the lowest frequency one should consider; (5) the investigation of the different stages of the production chain from crude oil prices to retail distribution - refining costs and margins, distribution and retailing costs and margins; (6) the examination of prices including and excluding taxes - excise and value-added; (7) the modelling of prices for three fuel types - passenger car petrol and diesel separately and home heating fuel oil; (8) lastly we also address the issue of possible asymmetries, allowing for the pass through to vary according to (a) whether price are increasing or decreasing and (b) whether price levels are above or below their equilibrium level. The main findings are as follows: First, as distribution and retailing costs and margins have been broadly stable on average, the modelling of the relationship between consumer prices excluding taxes and upstream prices in raw levels rather than in
International Nuclear Information System (INIS)
Costa, Gustavo Koury
2004-11-01
Although incompressible fluid flows can be regarded as a particular case of a general problem, numerical methods and the mathematical formulation aimed to solve compressible and incompressible flows have their own peculiarities, in such a way, that it is generally not possible to attain both regimes with a single approach. In this work, we start from a typically compressible formulation, slightly modified to make use of pressure variables and, through augmenting the stabilising parameters, we end up with a simplified model which is able to deal with a wide range of flow regimes, from supersonic to low speed gas flows. The resulting methodology is flexible enough to allow for the simulation of liquid flows as well. Examples using conservative and pressure variables are shown and the results are compared to those published in the literature, in order to validate the method. (author)
Shapes and rising velocities of single bubbles rising through an inner subchannel
International Nuclear Information System (INIS)
Tomiyama, Akio; Nakahara, Yusuke; Adachi, Yoshihiro; Hosokawa, Shigeo
2003-01-01
Shapes and velocities of single air bubbles rising through stagnant and flowing waters in an inner subchannel are measured by making use of fluorocarbon tubes. It is confirmed that (1) bubble shapes and motions in the subchannel are by far different from those in simple geometry, and they depend on the ratio λ of the bubble diameter to the subchannel hydraulic diameter, (2) when λ > 0.9, a part of a bubble intrudes into neighboring subchannels, and thereby a kind of void drift takes place even with a single bubble, (3) the terminal velocity V T of a small bubble (λ T for cell-Taylor bubbles (λ > 0.9) is presented, and (5) the rising velocity V B in laminar an turbulent flow conditions are well evaluated by substituting the proposed V T models and the ratio of the maximum liquid velocity to the mean liquid velocity into the Nicklin correlation. (author)
Oda, Hirokuni; Xuan, Chuang
2014-10-01
development of pass-through superconducting rock magnetometers (SRM) has greatly promoted collection of paleomagnetic data from continuous long-core samples. The output of pass-through measurement is smoothed and distorted due to convolution of magnetization with the magnetometer sensor response. Although several studies could restore high-resolution paleomagnetic signal through deconvolution of pass-through measurement, difficulties in accurately measuring the magnetometer sensor response have hindered the application of deconvolution. We acquired reliable sensor response of an SRM at the Oregon State University based on repeated measurements of a precisely fabricated magnetic point source. In addition, we present an improved deconvolution algorithm based on Akaike's Bayesian Information Criterion (ABIC) minimization, incorporating new parameters to account for errors in sample measurement position and length. The new algorithm was tested using synthetic data constructed by convolving "true" paleomagnetic signal containing an "excursion" with the sensor response. Realistic noise was added to the synthetic measurement using Monte Carlo method based on measurement noise distribution acquired from 200 repeated measurements of a u-channel sample. Deconvolution of 1000 synthetic measurements with realistic noise closely resembles the "true" magnetization, and successfully restored fine-scale magnetization variations including the "excursion." Our analyses show that inaccuracy in sample measurement position and length significantly affects deconvolution estimation, and can be resolved using the new deconvolution algorithm. Optimized deconvolution of 20 repeated measurements of a u-channel sample yielded highly consistent deconvolution results and estimates of error in sample measurement position and length, demonstrating the reliability of the new deconvolution algorithm for real pass-through measurements.
Single-photon emission tomography and cerebral blood flow
International Nuclear Information System (INIS)
Celsis, P.; Chan, M.; Marc-Vergnes, J.P.; Sveinsdottir, E.; Goldman, T.G.; Henriksen, L.; Paulson, O.B.; Stokely, E.M.; Lassen, N.A.
1982-01-01
This paper illustrates the capabilities of single-photon emission tomography in imaging local cerebral blood flows in man. The results purport the conclusion that a fairly good improvement has been achieved when compared to stationary detectors and that single-photon emission tomography is a well-suited tool for studying cerebral hemodynamics, especially within the framework of clinical studies [fr
Liu, Yu; Catalan, Jean-Cédric
2017-09-01
This paper studies the influence of an external mean flow on the sound transmission through finite clamped double-wall sandwich panels lined with poroelastic materials. Biot's theory is employed to describe wave propagation in poroelastic materials and various configurations of coupling the poroelastic layer to the facing plates are considered. The clamped boundary of finite panels are dealt with by the modal superposition theory and the weighted residual (Garlekin) method, leading to a matrix equation solution for the sound transmission loss (STL) through the structure. The theoretical model is validated against existing theories of infinite sandwich panels with and without an external flow. The numerical results of a single incident wave show that the external mean flow has significant effects on the STL which are coupled with the clamped boundary effect dominating in the low-frequency range. The external mean flow also influences considerably the limiting incidence angle of the panel system and the effect of the incidence angle on the STL. However, the influences of the azimuthal angle and the external flow orientation are negligible.
Measurement of the single and two phase flow using newly developed average bidirectional flow tube
International Nuclear Information System (INIS)
Yun, Byong Jo; Euh, Dong Jin; Kang, Kyung Ho; Song, Chul Hwa; Baek, Won Pil
2005-01-01
A new instrument, an average BDFT (Birectional Flow Tube), was proposed to measure the flow rate in single and two phase flows. Its working principle is similar to that of the pitot tube, wherein the dynamic pressure is measured. In an average BDFT, the pressure measured at the front of the flow tube is equal to the total pressure, while that measured at the rear tube is slightly less than the static pressure of the flow field due to the suction effect downstream. The proposed instrument was tested in air/water vertical and horizontal test sections with an inner diameter of 0.08m. The tests were performed primarily in single phase water and air flow conditions to obtain the amplification factor(k) of the flow tube in the vertical and horizontal test sections. Tests were also performed in air/water vertical two phase flow conditions in which the flow regimes were bubbly, slug, and churn turbulent flows. In order to calculate the phasic mass flow rates from the measured differential pressure, the Chexal dirft-flux correlation and a momentum exchange factor between the two phases were introduced. The test results show that the proposed instrument with a combination of the measured void fraction, Chexal drift-flux correlation, and Bosio and Malnes' momentum exchange model could predict the phasic mass flow rates within a 15% error. A new momentum exchange model was also proposed from the present data and its implementation provides a 5% improvement to the measured mass flow rate when compared to that with the Bosio and Malnes' model
Parametric study of fluid flow manipulation with piezoelectric macrofiber composite flaps
Sadeghi, O.; Tarazaga, P.; Stremler, M.; Shahab, S.
2017-04-01
Active Fluid Flow Control (AFFC) has received great research attention due to its significant potential in engineering applications. It is known that drag reduction, turbulence management, flow separation delay and noise suppression through active control can result in significantly increased efficiency of future commercial transport vehicles and gas turbine engines. In microfluidics systems, AFFC has mainly been used to manipulate fluid passing through the microfluidic device. We put forward a conceptual approach for fluid flow manipulation by coupling multiple vibrating structures through flow interactions in an otherwise quiescent fluid. Previous investigations of piezoelectric flaps interacting with a fluid have focused on a single flap. In this work, arrays of closely-spaced, free-standing piezoelectric flaps are attached perpendicular to the bottom surface of a tank. The coupling of vibrating flaps due to their interacting with the surrounding fluid is investigated in air (for calibration) and under water. Actuated flaps are driven with a harmonic input voltage, which results in bending vibration of the flaps that can work with or against the flow-induced bending. The size and spatial distribution of the attached flaps, and the phase and frequency of the input actuation voltage are the key parameters to be investigated in this work. Our analysis will characterize the electrohydroelastic dynamics of active, interacting flaps and the fluid motion induced by the system.
Single Pass Stripline Beam Position Monitor Design, Fabrication and Commissioning
Directory of Open Access Journals (Sweden)
McKinlay J.
2012-10-01
Full Text Available To monitor the position of the electron beam during transport from the Booster Synchrotron to the Storage Ring at the Australian Synchrotron, a stripline Beam Position Monitor (BPM has been designed, fabricated and installed in-house. The design was based on an existing stripline in the Booster and modified for the transfer line with a particular emphasis on ensuring the line impedance is properly matched to the detector system. The initial bench tests of a prototype stripline showed that the fabrication of the four individual striplines in the BPM was made precisely, each with a measured standing wave ratio (SWR of 1.8 at 500 MHz. Further optimization for impedance matching will be done for new stripline BPMs. The linearity and gain factor was measured with the detector system. The detector system that digitizes the signals is an Instrumentation Technologies Brilliance Single Pass [1]. The results show an error of 1 mm at an offset (from the electrical centre of 10 mm when a linear gain factor is assumed and an RMS noise of ~150 um that decreases to < 10 um with increasing signal intensity. The results were under our requirements for the transport line. The commissioning results of the stripline will also be presented showing a strong signal for an electron beam with an estimated integrated charge of ~50 nC with a position stability of 28 um (horizontal and 75 um (vertical.
Single Pass Stripline Beam Position Monitor Design, Fabrication and Commissioning
Tan, Y.-R. E.; Wang, D.; Van Garderen, E.; McKinlay, J.
2012-10-01
To monitor the position of the electron beam during transport from the Booster Synchrotron to the Storage Ring at the Australian Synchrotron, a stripline Beam Position Monitor (BPM) has been designed, fabricated and installed in-house. The design was based on an existing stripline in the Booster and modified for the transfer line with a particular emphasis on ensuring the line impedance is properly matched to the detector system. The initial bench tests of a prototype stripline showed that the fabrication of the four individual striplines in the BPM was made precisely, each with a measured standing wave ratio (SWR) of 1.8 at 500 MHz. Further optimization for impedance matching will be done for new stripline BPMs. The linearity and gain factor was measured with the detector system. The detector system that digitizes the signals is an Instrumentation Technologies Brilliance Single Pass [1]. The results show an error of 1 mm at an offset (from the electrical centre) of 10 mm when a linear gain factor is assumed and an RMS noise of ~150 um that decreases to < 10 um with increasing signal intensity. The results were under our requirements for the transport line. The commissioning results of the stripline will also be presented showing a strong signal for an electron beam with an estimated integrated charge of ~50 nC with a position stability of 28 um (horizontal) and 75 um (vertical).
The thermal performance of the two-pass, two-glass-cover solar air heater
Energy Technology Data Exchange (ETDEWEB)
Persad, P.; Sateunanathan, S.
1983-08-01
Analytic models are developed for the performance prediction of a two-glass-cover solar air heater operated in both the single-pass and two-pass modes. It is shown that the two-pass mode of operation is superior to the single-pass mode of operation over the range of collector inlet temperatures considered. This is seen to be mainly due to the fact that, in the two-pass mode of operation, the outer glass cover is cooled by the working fluid, thereby reducing the top losses. It is also shown that the performance in the two-pass mode of operation is independent of length, over the range of collector lengths considered, and that a critical plate spacing, dependent on the temperature level of operation of the collector, is indicated. Predicted values of performance are in good agreement with experimental results.
Fogel, Mark A; Li, Christine; Wilson, Felice; Pawlowski, Tom; Nicolson, Susan C; Montenegro, Lisa M; Diaz Berenstein, Laura; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Keller, Marc S; Harris, Matthew A; Whitehead, Kevin K; Clancy, Robert; Elci, Okan; Bethel, Jim; Vossough, Arastoo; Licht, Daniel J
2015-08-01
Patients with single ventricle can develop aortic-to-pulmonary collaterals (APCs). Along with systemic-to-pulmonary artery shunts, these structures represent a direct pathway from systemic to pulmonary circulations, and may limit cerebral blood flow (CBF). This study investigated the relationship between CBF and APC flow on room air and in hypercarbia, which increases CBF in patients with single ventricle. 106 consecutive patients with single ventricle underwent 118 cardiac magnetic resonance (CMR) scans in this cross-sectional study; 34 prior to bidirectional Glenn (BDG) (0.50±0.30 years old), 50 prior to Fontan (3.19±1.03 years old) and 34 3-9 months after Fontan (3.98±1.39 years old). Velocity mapping measured flows in the aorta, cavae and jugular veins. Analysis of variance (ANOVA) and multiple linear regression were used. Significance was pflow or body surface area, independent of age, cardiopulmonary bypass time, Po2 and Pco2 (R=-0.67--0.70 for all patients on room air, pflow was higher prior to BDG than in other stages. There is a strong inverse relationship between CBF and APC/shunt flow in patients with single ventricle throughout surgical reconstruction on room air and in hypercarbia independent of other factors. We speculate that APC/shunt flow may have a negative impact on cerebral development and neurodevelopmental outcome. Interventions on APC may modify CBF, holding out the prospect for improving neurodevelopmental trajectory. NCT02135081. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
A compact active grid for stirring pipe flow
Verbeek, A.A.; Pos, R.C.; Stoffels, G.G.M.; Geurts, B.J.; Meer, van der Th.
2013-01-01
A compact active grid is developed with which a pipe flow can be stirred in order to enhance the turbulence. The active grid is composed of a stationary and a rotating disk with characteristic hole patterns. This active grid is placed inside the pipe, allowing flow to pass through it. With only one
A compact active grid for stirring pipe flow
Verbeek, Antonie Alex; Pos, R.C.; Stoffels, Genie G.M.; Geurts, Bernardus J.; van der Meer, Theodorus H.
A compact active grid is developed with which a pipe flow can be stirred in order to enhance the turbulence. The active grid is composed of a stationary and a rotating disk with characteristic hole patterns. This active grid is placed inside the pipe, allowing flow to pass through it. With only one
A First-Order One-Pass CPS Transformation
DEFF Research Database (Denmark)
Danvy, Olivier; Nielsen, Lasse Reichstein
2001-01-01
We present a new transformation of λ-terms into continuation-passing style (CPS). This transformation operates in one pass and is both compositional and first-order. Previous CPS transformations only enjoyed two out of the three properties of being first-order, one-pass, and compositional......, but the new transformation enjoys all three properties. It is proved correct directly by structural induction over source terms instead of indirectly with a colon translation, as in Plotkin's original proof. Similarly, it makes it possible to reason about CPS-transformed terms by structural induction over...... source terms, directly.The new CPS transformation connects separately published approaches to the CPS transformation. It has already been used to state a new and simpler correctness proof of a direct-style transformation, and to develop a new and simpler CPS transformation of control-flow information....
A First-Order One-Pass CPS Transformation
DEFF Research Database (Denmark)
Danvy, Olivier; Nielsen, Lasse Reichstein
2003-01-01
We present a new transformation of λ-terms into continuation-passing style (CPS). This transformation operates in one pass and is both compositional and first-order. Previous CPS transformations only enjoyed two out of the three properties of being first-order, one-pass, and compositional......, but the new transformation enjoys all three properties. It is proved correct directly by structural induction over source terms instead of indirectly with a colon translation, as in Plotkin's original proof. Similarly, it makes it possible to reason about CPS-transformed terms by structural induction over...... source terms, directly.The new CPS transformation connects separately published approaches to the CPS transformation. It has already been used to state a new and simpler correctness proof of a direct-style transformation, and to develop a new and simpler CPS transformation of control-flow information....
A self-regulating valve for single-phase liquid cooling of microelectronics
International Nuclear Information System (INIS)
Donose, Radu; De Volder, Michaël; Peirs, Jan; Reynaerts, Dominiek
2011-01-01
This paper reports on the design, optimization and testing of a self-regulating valve for single-phase liquid cooling of microelectronics. Its purpose is to maintain the integrated circuit (IC) at constant temperature and to reduce power consumption by diminishing flow generated by the pump as a function of the cooling requirements. It uses a thermopneumatic actuation principle that combines the advantages of zero power consumption and small size in combination with a high flow rate and low manufacturing costs. The valve actuation is provided by the thermal expansion of a liquid (actuation fluid) which, at the same time, actuates the valve and provides feed-back sensing. A maximum flow rate of 38 kg h −1 passes through the valve for a heat load up to 500 W. The valve is able to reduce the pumping power by up to 60% and it has the capability to maintain the IC at a more uniform temperature.
Bioaugmentation of flow-through sand filters
DEFF Research Database (Denmark)
Samuelsen, Elin Djurhuus
for degradation performances in flow-through sand columns, with the aim of identifying a suitable inoculant strain for future environmental applications. Another aim was to identify a suitable genetic marker to monitor phenoxy acid degradation in strain Sphingobium sp. PM2. We were not able to link motility...... and biofilm formation to the strains´ ability to adhere to sand. Nevertheless, a correlation was found between cell surface hydrophobicity and adhesion and overall degradation performances in flow-through sand columns. We identified S phingobium sp. PM2 as a promising inoculant strain, displaying efficient...... MCPA degradation for prolonged periods in flow-through sand columns. In an expression study of catabolic genes with putative roles in phenoxy acid degradation, we observed a marked upregulation of catabolic genes cadA and tfdC upon exposure to MCPA, 2,4-D, dichlorprop and mecoprop in strain PM2, which...
Computed Flow Through An Artificial Heart And Valve
Rogers, Stuart E.; Kwak, Dochan; Kiris, Cetin; Chang, I-Dee
1994-01-01
NASA technical memorandum discusses computations of flow of blood through artificial heart and through tilting-disk artificial heart valve. Represents further progress in research described in "Numerical Simulation of Flow Through an Artificial Heart" (ARC-12478). One purpose of research to exploit advanced techniques of computational fluid dynamics and capabilities of supercomputers to gain understanding of complicated internal flows of viscous, essentially incompressible fluids like blood. Another to use understanding to design better artificial hearts and valves.
Mouse myocardial first-pass perfusion MR imaging
Coolen, Bram F.; Moonen, Rik P. M.; Paulis, Leonie E. M.; Geelen, Tessa; Nicolay, Klaas; Strijkers, Gustav J.
2010-01-01
A first-pass myocardial perfusion sequence for mouse cardiac MRI is presented. A segmented ECG-triggered acquisition combined with parallel imaging acceleration was used to capture the first pass of a Gd-DTPA bolus through the mouse heart with a temporal resolution of 300-400 msec. The method was
Factors that affect the calibration of turbines in single-phase flow
International Nuclear Information System (INIS)
Piper, T.C.
1977-05-01
Basic turbine operation in single-phase flow is related. Causes and relative magnitudes of retarding torque are given for two sizes of turbines when used for water flow measurement. An equation for slip caused by retarding torques is given. Evaluation of turbine slip behavior at the turbine low flow region shows that bearing retarding torques, change in flow patterns, or other effects can predominate in the relatively large changes in the calibration ''constant'' that occurs there. Fluid lubricity is singled out as an important fluid property in certain types of bearings and flow. Temperature induced changes in turbine size are shown to cause calibration changes if a turbine is used at a temperature significantly different than that at which it was calibrated
Factors that affect the calibration of turbines in single-phase flow
Energy Technology Data Exchange (ETDEWEB)
Piper, T. C.
1977-05-01
Basic turbine operation in single-phase flow is related. Causes and relative magnitudes of retarding torque are given for two sizes of turbines when used for water flow measurement. An equation for slip caused by retarding torques is given. Evaluation of turbine slip behavior at the turbine low flow region shows that bearing retarding torques, change in flow patterns, or other effects can predominate in the relatively large changes in the calibration ''constant'' that occurs there. Fluid lubricity is singled out as an important fluid property in certain types of bearings and flow. Temperature induced changes in turbine size are shown to cause calibration changes if a turbine is used at a temperature significantly different than that at which it was calibrated.
Mouse myocardial first-pass perfusion MR imaging
Coolen, B.F.; Moonen, R.P.M.; Paulis, L.E.M.; Geelen, T.; Nicolay, K.; Strijkers, G.J.
2010-01-01
A first-pass myocardial perfusion sequence for mouse cardiac MRI is presented. A segmented ECG-triggered acquisition combined with parallel imaging acceleration was used to capture the first pass of a Gd-DTPA bolus through the mouse heart with a temporal resolution of 300–400 msec. The method was
Foam flows through a local constriction
Chevalier, T.; Koivisto, J.; Shmakova, N.; Alava, M. J.; Puisto, A.; Raufaste, C.; Santucci, S.
2017-11-01
We present an experimental study of the flow of a liquid foam, composed of a monolayer of millimetric bubbles, forced to invade an inhomogeneous medium at a constant flow rate. To model the simplest heterogeneous fracture medium, we use a Hele-Shaw cell consisting of two glass plates separated by a millimetric gap, with a local constriction. This single defect localized in the middle of the cell reduces locally its gap thickness, and thus its local permeability. We investigate here the influence of the geometrical property of the defect, specifically its height, on the average steady-state flow of the foam. In the frame of the flowing foam, we can observe a clear recirculation around the obstacle, characterized by a quadrupolar velocity field with a negative wake downstream the obstacle, which intensity evolves systematically with the obstacle height.
Evaluation of renal first pass blood flow with a functional image technique in hypertensive patients
International Nuclear Information System (INIS)
Ishibashi, Masatoshi; Morita, Seiichiro; Umezaki, Noriyoshi; Ohtake, Hisashi
1988-01-01
The renal circulation of patients with essential hypertension and renovascular hypertension was evaluated using 99m Tc-DTPA. The first renal peak count (the first C max ; FC max ), time phase distribution (the first T max ; FT max ), and blood velocity (the FC max /FT max ) were calculated by digital imaging. This yields a visual image of the renal circulation. We consider that the increase in the renal first pass blood flow in patients with essential hypertension is best observed pixel by pixel. The FC max and FC max /FT max images before and after treatment by percutaneous transluminal renal angioplasty in patients with renovascular hypertension clearly show its therapeutic effect. The FI technique, therefore, has the advantage that it can be performed at the same time as the conventional routine examinations of renal function. This makes it very useful clinically. (orig.)
International Nuclear Information System (INIS)
Seo, Jae Kwang; Choi, Ki Yong; Kang, Han Ok; Kim, Young In; Yoon, Ju Hyeon; Zee, Sung Qunn
2005-01-01
The design features of a once-through steam generator (OTSG) for an integral reactor are significantly different from the commercial U-tube type steam generator from several aspects such as the general arrangement, size, operation conditions, and so on. Therefore a sufficient understanding of the thermal-hydraulic characteristics of the OTSG is essential for the design of the nuclear steam supply system (NSSS) and the power conversion system (PCS). It is also necessary to develop operation procedures complying to the unique design features of the OTSG of interest. The OTSG is sized to produce a sufficiently superheated steam during a normal power operation and therefore the secondary system can be simple relative to that of the other types of steam generators. For the plant adopting the OTSG, the steam pressure in the secondary circuit (tube side of the OTSG) is controlled to be constant during a normal power operation. Constant steam pressure is realized by regulating the control valve on the main steam line dedicated for this purpose. However during a heatup operation, at which the fluid state at the exit of the OTSG is a single phase hot water or two phases, it is not proper to use the control valve on the main steam line due to a control problem at low and multi-phase flow conditions and possibly an erosion problem. For these reasons, another dedicated line called a startup cooling line is used during a heatup condition. There may be several operational conditions for the secondary fluid required to pass through during heatup operation, depending on the design of the PCS. In general, there are two conditions: One is a condition for a vacuum operation for the condenser and another is an entry condition for a steam pressure control operation for an auxiliary power system. In this study, the concept of using a simple startup cooling line with a fixed flow resistance and changing the feedwater flow for the pressure control of the PCS during a heatup period are
A Tunable CW Orange Laser Based on a Cascaded MgO:PPLN Single-Pass Sum-Frequency Generation Module
Dismas K. Choge; Huai-Xi Chen; Bao-Lu Tian; Yi-Bin Xu; Guang-Wei Li; Wan-Guo Liang
2018-01-01
We report an all-solid-state continuous wave (CW) tunable orange laser based on cascaded single-pass sum-frequency generation with fundamental wavelengths at 1545.7 and 975.2 nm using two quasi-phase-matched (QPM) MgO-doped periodically poled lithium niobate (MgO:PPLN) crystals. Up to 10 mW of orange laser is generated in the cascaded module corresponding to a 10.4%/W nonlinear conversion efficiency. The orange output showed a temperature tuning rate of ~0.05 nm/°C, and the beam quality (M2) ...
Investigation of the Taylor vortices in electrovortex flow
Vinogradov, D. A.; Ivochkin, Yu P.; Teplyakov, I. O.
2017-10-01
The structure of the electrovortex flow appearing when the electric current passing through the liquid metal interacts with own and external magnetic fields was investigated numerically. It was shown that axial external magnetic field leads to the rotation of the liquid and generates secondary flow similar to Taylor vortex. Calculations were carried out for various ratios of electrode sizes.
Notes on basis band-pass circuits; Notes sur les circuits de base passe-bande
Energy Technology Data Exchange (ETDEWEB)
Ailloud, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1959-07-01
Resistor load amplifier stages, basic band-pass RC networks, conventional single-tuned circuits, have the same transfer function. Common properties and differences because diverse magnitude of parameters with proposed problems are exposed. Next the case of several cascaded stages (or networks) is examined when there is no reaction ones to another. (author) [French] Les etages amplificateurs a resistances, les circuits passe-bande RC elementaires, le circuit resonnant classique possedent la meme fonction de transfert. On fait ressortir les proprietes communes et les differences de comportement dues aux ordres de grandeur qu'il est possible de donner aux parametres en fonction des problemes a resoudre. On examine ensuite le cas de plusieurs etages (ou de plusieurs circuits) en cascade lorsqu'ils ne reagissent pas les uns sur les autres. (auteur)
Yang, Guowei; You, Shengzui; Bi, Meihua; Fan, Bing; Lu, Yang; Zhou, Xuefang; Li, Jing; Geng, Hujun; Wang, Tianshu
2017-09-10
Free-space optical (FSO) communication utilizing a modulating retro-reflector (MRR) is an innovative way to convey information between the traditional optical transceiver and the semi-passive MRR unit that reflects optical signals. The reflected signals experience turbulence-induced fading in the double-pass channel, which is very different from that in the traditional single-pass FSO channel. In this paper, we consider the corner cube reflector (CCR) as the retro-reflective device in the MRR. A general geometrical model of the CCR is established based on the ray tracing method to describe the ray trajectory inside the CCR. This ray tracing model could treat the general case that the optical beam is obliquely incident on the hypotenuse surface of the CCR with the dihedral angle error and surface nonflatness. Then, we integrate this general CCR model into the wave-optics (WO) simulation to construct the double-pass beam propagation simulation. This double-pass simulation contains the forward propagation from the transceiver to the MRR through the atmosphere, the retro-reflection of the CCR, and the backward propagation from the MRR to the transceiver, which can be realized by a single-pass WO simulation, the ray tracing CCR model, and another single-pass WO simulation, respectively. To verify the proposed CCR model and double-pass WO simulation, the effective reflection area, the incremental phase, and the reflected beam spot on the transceiver plane of the CCR are analyzed, and the numerical results are in agreement with the previously published results. Finally, we use the double-pass WO simulation to investigate the double-pass channel in the MRR FSO systems. The histograms of the turbulence-induced fading in the forward and backward channels are obtained from the simulation data and are fitted by gamma-gamma (ΓΓ) distributions. As the two opposite channels are highly correlated, we model the double-pass channel fading by the product of two correlated
Umari, Amjad; Fahy, Michael F.; Earle, John D.; Tucci, Patrick
2008-01-01
To evaluate the potential for transport of radionuclides in ground water from the proposed high-level nuclear-waste repository at Yucca Mountain, Nevada, conservative (nonsorbing) tracer tests were conducted among three boreholes, known as the C-hole Complex, and values for transport (or flow) porosity, storage (or matrix) porosity, longitudinal dispersivity, and the extent of matrix diffusion were obtained. The C-holes are completed in a sequence of Miocene tuffaceous rock, consisting of nonwelded to densely welded ash-flow tuff with intervals of ash-fall tuff and volcaniclastic rocks, covered by Quaternary alluvium. The lower part of the tuffaceous-rock sequence includes the Prow Pass, Bullfrog, and Tram Tuffs of the Crater Flat Group. The rocks are pervaded by tectonic and cooling fractures. Paleozoic limestone and dolomite underlie the tuffaceous rocks. Four radially convergent and one partially recirculating conservative (nonsorbing) tracer tests were conducted at the C-hole Complex from 1996 to 1998 to establish values for flow porosity, storage porosity, longitudinal dispersivity, and extent of matrix diffusion in the Bullfrog and Tram Tuffs and the Prow Pass Tuff. Tracer tests included (1) injection of iodide into the combined Bullfrog-Tram interval; (2) injection of 2,6 difluorobenzoic acid into the Lower Bullfrog interval; (3) injection of 3-carbamoyl-2-pyridone into the Lower Bullfrog interval; and (4) injection of iodide and 2,4,5 trifluorobenzoic acid, followed by 2,3,4,5 tetrafluorobenzoic acid, into the Prow Pass Tuff. All tracer tests were analyzed by the Moench single- and dual-porosity analytical solutions to the advection-dispersion equation or by superposition of these solutions. Nonlinear regression techniques were used to corroborate tracer solution results, to obtain optimal parameter values from the solutions, and to quantify parameter uncertainty resulting from analyzing two of the three radially convergent conservative tracer tests
Pressure drop in flashing flow through obstructions
International Nuclear Information System (INIS)
Weinle, M.E.; Johnston, B.S.
1985-01-01
An experiment was designed to investigate the pressure drop for flashing flow across obstructions of different geometries at various flow rates. Tests were run using two different orifices to determine if the two-phase pressure drop could be characterized by the single phase loss coefficient and the general behavior of the two-phase multiplier. For the geometries studied, it was possible to correlate the multiplier in a geometry-independent fashion
Analysis of Biomechanical Structure and Passing Techniques in Basketball
Ricardo E. Izzo; Luca Russo
2011-01-01
The basketball is a complex sport, which these days has become increasingly linked to its’ psychophysical aspects rather than to the technical ones. Therefore, it is important to make a through study of the passing techniques from the point of view of the type of the pass and its’ biomechanics. From the point of view of the type of the used passes, the most used is the two-handed chest pass with a frequency of 39.9%. This is followed, in terms of frequency, by one-handed passes – the baseball...
Performance and cost benefits analysis of double-pass solar collector with and without fins
International Nuclear Information System (INIS)
Fudholi, Ahmad; Sopian, Kamaruzzaman; Ruslan, Mohd Hafidz; Othman, Mohd Yusof
2013-01-01
Highlights: • The thermal performances and cost analysis of the double-pass solar collector with and without fins absorber were discussed. • The theoretical and experimental study on the double-pass solar air collector with and without fins absorber was conducted. • The ratio of AC/AEG or the cost benefit ratio was presented. • The double-pass solar collector with fins absorber is more cost-effective compared to without fins absorber. - Abstract: The performance and cost benefit analysis of double-pass solar collector with and without fins have been conducted. The theoretical model using steady state analysis has been developed and compared with the experimental results. The performance curves of the double-pass solar collector with and without fins, which included the effects of mass flow rate and solar intensity on the thermal efficiency of the solar collector, were obtained. Results indicated that the thermal efficiency is proportional to the solar intensity at a specific mass flow rate. The thermal efficiency increased by 9% at a solar intensity of 425–790 W/m 2 and mass flow rate of 0.09 kg/s. The theoretical and experimental analysis showed a similar trend as well as close agreement. Moreover, a cost-effectiveness model has been developed examine the cost benefit ratio of double-pass solar collector with and without fins. Evaluation of the annual cost (AC) and the annual energy gain (AEG) of the collector were also performed. The results show that the double-pass solar collector with fins is more cost-effective compared to the double-pass solar collector without fins for mass flow rate of 0.01–0.07 kg/s. Also, simulations were obtained for the double-pass solar collector with fins at Nusselt number of 5.42–36.21. The energy efficiency of collector increases with the increase of Nusselt number. The results show that by increasing the Nusselt number simultaneously would drop the outlet temperature at any solar intensity. Increase in Nusselt number
Capacitive deionization of arsenic-contaminated groundwater in a single-pass mode.
Fan, Chen-Shiuan; Liou, Sofia Ya Hsuan; Hou, Chia-Hung
2017-10-01
A single-pass-mode capacitive deionization (CDI) reactor was used to remove arsenic from groundwater in the presence of multiple ions. The CDI reactor involved an applied voltage of 1.2 V and six cell pairs of activated carbon electrodes, each of which was 20 × 30 cm 2 . The results indicate that this method achieved an effluent arsenic concentration of 0.03 mg L -1 , which is lower than the arsenic concentration standard for drinking water and irrigation sources in Taiwan, during the charging stage. Additionally, the ability of the CDI to remove other coexisting ions was studied. The presence of other ions has a significant influence on the removal of arsenic from groundwater. From the analysis of the electrosorption selectivity, the preference for anion removal could be ordered as follows: NO 3 - > SO 4 2- > F - > Cl - >As. The electrosorption selectivity for cations could be ordered as follows: Ca 2+ > Mg 2+ > Na + ∼ K + . Moreover, monovalent cations can be replaced by divalent cations at the electrode surface in the later period of the electrosorption stage. Consequently, activated carbon-based capacitive deionization is demonstrated to be a high-potential technology for remediation of arsenic-contaminated groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.
Industrial pricing in Brazil in the 2010s: The pass-through effect
Directory of Open Access Journals (Sweden)
Felipe Câmara
2017-01-01
Full Text Available The aim of this paper is to discuss the impact of costs on industrial inflation in Brazil. Assuming that inflation is mainly cost-push, this paper estimates the exchange rate pass-through on industrial prices. Based on Kalecki’s price equation, the paper explores data from the producer price index from 2010 onward. One of the main findings is that more than 60% of the inflationary acceleration in the industrial prices can be explained by exchange rate devaluations. The econometric exercise also showed that when demand increases, even if labor unit costs do not change, firms increase their profit margin. Finally, the paper questions the effectiveness of the inflation targeting policy, when the diagnosis to the pressure on prices comes from the costs, and not from demand.
Parametric analysis of plastic strain and force distribution in single pass metal spinning
International Nuclear Information System (INIS)
Choudhary, Shashank; Tejesh, Chiruvolu Mohan; Regalla, Srinivasa Prakash; Suresh, Kurra
2013-01-01
Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India
Parametric analysis of plastic strain and force distribution in single pass metal spinning
Choudhary, Shashank; Tejesh, Chiruvolu Mohan; Regalla, Srinivasa Prakash; Suresh, Kurra
2013-12-01
Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India.
Parametric analysis of plastic strain and force distribution in single pass metal spinning
Energy Technology Data Exchange (ETDEWEB)
Choudhary, Shashank, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Tejesh, Chiruvolu Mohan, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Regalla, Srinivasa Prakash, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Suresh, Kurra, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in [Department of Mechanical Engineering, BITS-Pilani, Hyderabad Campus, Shamirpet, Hyderabad, 500078, Andhra Pradesh (India)
2013-12-16
Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India.
Trelles, Mario A; Vélez, Mariano; Mordon, Serge
2008-03-01
Ablative fractional resurfacing shows promise for skin resurfacing and tightening and also to improve treatment of epidermal and dermal pigmentary disorders. This study aimed at determining any correlation between epidermal ablation and effects on the dermis when using an Er:YAG laser in ablative fractional resurfacing mode. Ten female subjects participated in the study, mean age 52 years, Skin phototypes: 1 Fitzpatrick type II; 8 type III and 1 type IV. The degree of wrinkles (Glogau scale II or III) was similar in all cases. The laser used was the Pixel Er:YAG system (Alma Lasertrade mark, Israel) which delivers the laser beam via a hand-piece equipped with a beam splitter to divide the 2,940 nm beam into various microbeams of 850 microm in diameter in an 11 mmx11 mm treatment area. Using a constant energy of 1,400 mJ/cm(2), on a test area of 4 cmx2 cm. Two, 4, 6, and 8 passes on the preauricular area of the face were evaluated immediately after treatment. In all cases, the handpiece was kept in the same position, and rotated slightly around its perpendicular axis between passes, then moved on to the next spot. Biopsies were performed and tissue samples were routinely processed and stained with hematoxylin and eosin (H&E). No patient reported any noticeable discomfort, even at 8 passes. The histological findings revealed that, independent of the degree of the wrinkles, more laser passes produced more ablative removal of the epidermis. Residual thermal damage (RTD) with 2 laser passes was not observed but with 4 and 6 passes increased thermal effects and vacuole formation in the epidermal cells were noticed. With 8 laser passes, total epidermal removal was seen together with frank RTD-related changes in the upper part of the papillary dermis. In this study, we have demonstrated that high density fractional Er:YAG laser energy in a single session with multiple passes targeted not only the skin surface with elimination of the epidermis, but could also achieve heat
Structure of the gas-liquid annular two-phase flow in a nozzle section
International Nuclear Information System (INIS)
Yoshida, Kenji; Kataoka, Isao; Ohmori, Syuichi; Mori, Michitsugu
2006-01-01
Experimental studies on the flow behavior of gas-liquid annular two-phase flow passing through a nozzle section were carried out. This study is concerned with the central steam jet injector for a next generation nuclear reactor. In the central steam jet injector, steam/water annular two-phase flow is formed at the mixing nozzle. To make an appropriate design and to establish the high-performance steam injector system, it is very important to accumulate the fundamental data of the thermo-hydro dynamic characteristics of annular flow passing through a nozzle section. On the other hand, the transient behavior of multiphase flow, in which the interactions between two-phases occur, is one of the most interesting scientific issues and has attracted research attention. In this study, the transient gas-phase turbulence modification in annular flow due to the gas-liquid phase interaction is experimentally investigated. The annular flow passing through a throat section is under the transient state due to the changing cross sectional area of the channel and resultantly the superficial velocities of both phases are changed compared with a fully developed flow in a straight pipe. The measurements for the gas-phase turbulence were precisely performed by using a constant temperature hot-wire anemometer, and made clear the turbulence structure such as velocity profiles, fluctuation velocity profiles. The behavior of the interfacial waves in the liquid film flow such as the ripple or disturbance waves was also observed. The measurements for the liquid film thickness by the electrode needle method were also performed to measure the base film thickness, mean film thickness, maximum film thickness and wave height of the ripple or the disturbance waves. (author)
A novel SFG structure for C-T high-pass filters
Nielsen, Ivan Riis
1993-01-01
A signal flow graph (SFG) structure for simulating passive high-pass ladder filters, called the incremental integration structure, is proposed. The structure requires the use of integrators with nonintegrating inputs, and an implementation based on the MOSFET-C technique is discussed. The incremental integration structure is compared to the leapfrog and direct SFG simulation structures. Leapfrog high-pass filters are relatively simple and show good noise properties, but they are based on diff...
Sanni, O.; Bukuaghangin, O.; Huggan, M.; Kapur, N.; Charpentier, T.; Neville, A.
2017-10-01
There is a considerable interest to investigate surface crystallization in order to have a full mechanistic understanding of how layers of sparingly soluble salts (scale) build on component surfaces. Despite much recent attention, a suitable methodology to improve on the understanding of the precipitation/deposition systems to enable the construction of an accurate surface deposition kinetic model is still needed. In this work, an experimental flow rig and associated methodology to study mineral scale deposition is developed. The once-through flow rig allows us to follow mineral scale precipitation and surface deposition in situ and in real time. The rig enables us to assess the effects of various parameters such as brine chemistry and scaling indices, temperature, flow rates, and scale inhibitor concentrations on scaling kinetics. Calcium carbonate (CaCO3) scaling at different values of the saturation ratio (SR) is evaluated using image analysis procedures that enable the assessment of surface coverage, nucleation, and growth of the particles with time. The result for turbidity values measured in the flow cell is zero for all the SR considered. The residence time from the mixing point to the sample is shorter than the induction time for bulk precipitation; therefore, there are no crystals in the bulk solution as the flow passes through the sample. The study shows that surface scaling is not always a result of pre-precipitated crystals in the bulk solution. The technique enables both precipitation and surface deposition of scale to be decoupled and for the surface deposition process to be studied in real time and assessed under constant condition.
Fogel, Mark A; Li, Christine; Elci, Okan U; Pawlowski, Tom; Schwab, Peter J; Wilson, Felice; Nicolson, Susan C; Montenegro, Lisa M; Diaz, Laura; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Mascio, Christopher; Keller, Marc S; Harris, Matthew A; Whitehead, Kevin K; Bethel, Jim; Vossough, Arastoo; Licht, Daniel J
2017-02-14
Patients with a single ventricle experience a high rate of brain injury and adverse neurodevelopmental outcome; however, the incidence of brain abnormalities throughout surgical reconstruction and their relationship with cerebral blood flow, oxygen delivery, and carbon dioxide reactivity remain unknown. Patients with a single ventricle were studied with magnetic resonance imaging scans immediately prior to bidirectional Glenn (pre-BDG), before Fontan (BDG), and then 3 to 9 months after Fontan reconstruction. One hundred sixty-eight consecutive subjects recruited into the project underwent 235 scans: 63 pre-BDG (mean age, 4.8±1.7 months), 118 BDG (2.9±1.4 years), and 54 after Fontan (2.4±1.0 years). Nonacute ischemic white matter changes on T2-weighted imaging, focal tissue loss, and ventriculomegaly were all more commonly detected in BDG and Fontan compared with pre-BDG patients ( P <0.05). BDG patients had significantly higher cerebral blood flow than did Fontan patients. The odds of discovering brain injury with adjustment for surgical stage as well as ≥2 coexisting lesions within a patient decreased (63%-75% and 44%, respectively) with increasing amount of cerebral blood flow ( P <0.05). In general, there was no association of oxygen delivery (except for ventriculomegaly in the BDG group) or carbon dioxide reactivity with neurological injury. Significant brain abnormalities are commonly present in patients with a single ventricle, and detection of these lesions increases as children progress through staged surgical reconstruction, with multiple coexisting lesions more common earlier than later. In addition, this study demonstrated that BDG patients had greater cerebral blood flow than did Fontan patients and that an inverse association exists of various indexes of cerebral blood flow with these brain lesions. However, CO 2 reactivity and oxygen delivery (with 1 exception) were not associated with brain lesion development. URL: http
International Nuclear Information System (INIS)
Takemura, T.; Roko, K.; Shiraha, M.; Midoriyama, S.
1986-01-01
Experimental results are presented on the flow behavior, pressure drop characteristics, and dryout characteristics by joule heating for the gas-water flow through U-shaped and inverted U-shaped tubes invertical plane. The height of the vertical straight section of the test tube is 4100 mm, and two bend radii, 116 mm and 435 mm, are chosen for the experiments. The test tubes used are of transparent acrylic resin for the flow behavior test, and of stainless steel for the other tests, inside diameter being 18 mm for the former and 18.5 mm for the latter. Flow patterns in the vertical upflow and downflow sections are shown on the diagram of the superficial gas velocity versus liquid velocity. Further, the flow behavior in the bend section is made clear in relation to flow rates of gas and liquid. The pressure drop between inlet and outlet of the test tube for the made clear in relation to flow rates of gas and liquid. The pressure drop between inlet and outlet of the test tube for the two-phase flow is shown in comparison with that for the single-phase flow of water. The threshold conditions of dryout in the bend section by joule heatig are shown on the diagram of the superficial gas velocity versus liquid velocity. The location of the dryout in the bend section is also clarified. (orig.)
DEFF Research Database (Denmark)
Jensen, Kaare Hartvig; Valente, Andre X. C. N.; Stone, Howard A.
2014-01-01
We examine the fluid mechanics of viscous flow through filters consisting of perforated thin plates. We classify the effects that contribute to the hydraulic resistance of the filter. Classical analyses assume a single pore size and account only for filter thickness. We extend these results to ob...
Ramos, A.; Calas, H.; Diez, L.; Moreno, E.; Prohías, J.; Villar, A.; Carrillo, E.; Jiménez, A.; Pereira, W. C. A.; Von Krüger, M. A.
The cardio-pathology by ischemia is an important cause of death, but the re-vascularization of coronary arteries (by-pass operation) is an useful solution to reduce associated morbidity improving quality of life in patients. During these surgeries, the flow in coronary vessels must be measured, using non-invasive ultrasonic methods, known as transit time flow measurements (TTFM), which are the most accurate option nowadays. TTFM is a common intra-operative tool, in conjunction with classic Doppler velocimetry, to check the quality of these surgery processes for implanting grafts in parallel with the coronary arteries. This work shows important improvements achieved in flow-metering, obtained in our research laboratories (CSIC, ICIMAF, COPPE) and tested under real surgical conditions in Cardiocentro-HHA, for both narrowband NB and broadband BB regimes, by applying results of a CYTED multinational project (Ultrasonic & computational systems for cardiovascular diagnostics). mathematical models and phantoms were created to evaluate accurately flow measurements, in laboratory conditions, before our new electronic designs and low-cost implementations, improving previous ttfm systems, which include analogic detection, acquisition & post-processing, and a portable PC. Both regimes (NB and BB), with complementary performances for different conditions, were considered. Finally, specific software was developed to offer facilities to surgeons in their interventions.
Device for controlling a recirculation flow in a reactor
International Nuclear Information System (INIS)
Shida, Toichi; Tohei, Kazushige; Hirose, Masao; Nakamura, Hideo.
1976-01-01
Object: To provide an emergency cut-off valve in a recirculation system in a reactor to control the recirculation at the time of turbine trip or load cut-off, thereby relieving excessive increase in heat output of fuel. Structure: A recirculation pump is driven through a recirculation pump motor by an AC generator, which is driven by a driving motor through a fluid coupling, so that reactor water passes the emergency cut-off valve and recirculation flow stop valve and then passes a jet pump into the core. At the time of turbine trip or load cut-off, the emergency cut-off valve is closed by a hydraulic circuit, whereby core flow is merely decreased by 20 to 30% in a short period of time to restrain excessive increase in heat output. (Yoshino, Y.)
Theoretical and laboratory investigations of flow through fractures in crystalline rock
International Nuclear Information System (INIS)
Witherspoon, P.A.; Watkins, D.J.; Tsang, Y.W.
1981-01-01
A theoretical model developed for flow through a deformable fracture subject to stresses was successfully tested against laboratory experiments. The model contains no arbitrary parameters and can be used to predict flow rates through a single fracture if the fractional fracture contact area can be estimated and if stress-deformation data are available. These data can be obtained from laboratory or in situ tests. The model has considerable potential for practical application. The permeability of ultralarge samples of fractured crystalline rock as a function of stresses was measured. Results from tests on a pervasively fractured 1-m-diameter specimen of granitic rock showed that drastically simplifying assumptions must be used to apply theoretical models to this type of rock mass. Simple models successfully reproduce the trend of reduced permeability as stress is applied in a direction normal to the fracture plane. The tests also demonstrated how fracture conductivity increases as a result of dilatancy associated with shear displacements. The effect of specimen size on the hydraulic properties of fractured rock was also investigated. Permeability tests were performed on specimens of charcoal black granite containing a single fracture subjected to normal stress. Results are presented for tests performed on a 0.914-m-diameter specimen and on the same specimen after it had been reduced to 0.764 m in diameter. The data show that fracture conductivity is sensitive to stress history and sample disturbance
A novel SFG structure for C-T high-pass filters
DEFF Research Database (Denmark)
Nielsen, Ivan Riis
1993-01-01
A signal flow graph (SFG) structure for simulating passive high-pass ladder filters, called the incremental integration structure, is proposed. The structure requires the use of integrators with nonintegrating inputs, and an implementation based on the MOSFET-C technique is discussed. The increme......A signal flow graph (SFG) structure for simulating passive high-pass ladder filters, called the incremental integration structure, is proposed. The structure requires the use of integrators with nonintegrating inputs, and an implementation based on the MOSFET-C technique is discussed....... The incremental integration structure is compared to the leapfrog and direct SFG simulation structures. Leapfrog high-pass filters are relatively simple and show good noise properties, but they are based on differentiators and thus stability problems exist. The direct SFG simulation method is based on integrators...... and has good stability properties, but it leads to a relatively high circuit complexity and a high noise level. However, the incremental integration structure inherits the low-noise properties of the leapfrog structure and the good stability of the direct SFG simulation method. A sixth-order elliptic high...
SFG synthesis of general high-order all-pass and all-pole current transfer functions using CFTAs.
Tangsrirat, Worapong
2014-01-01
An approach of using the signal flow graph (SFG) technique to synthesize general high-order all-pass and all-pole current transfer functions with current follower transconductance amplifiers (CFTAs) and grounded capacitors has been presented. For general nth-order systems, the realized all-pass structure contains at most n + 1 CFTAs and n grounded capacitors, while the all-pole lowpass circuit requires only n CFTAs and n grounded capacitors. The resulting circuits obtained from the synthesis procedure are resistor-less structures and especially suitable for integration. They also exhibit low-input and high-output impedances and also convenient electronic controllability through the g m-value of the CFTA. Simulation results using real transistor model parameters ALA400 are also included to confirm the theory.
SFG Synthesis of General High-Order All-Pass and All-Pole Current Transfer Functions Using CFTAs
Directory of Open Access Journals (Sweden)
Worapong Tangsrirat
2014-01-01
Full Text Available An approach of using the signal flow graph (SFG technique to synthesize general high-order all-pass and all-pole current transfer functions with current follower transconductance amplifiers (CFTAs and grounded capacitors has been presented. For general nth-order systems, the realized all-pass structure contains at most n + 1 CFTAs and n grounded capacitors, while the all-pole lowpass circuit requires only n CFTAs and n grounded capacitors. The resulting circuits obtained from the synthesis procedure are resistor-less structures and especially suitable for integration. They also exhibit low-input and high-output impedances and also convenient electronic controllability through the gm-value of the CFTA. Simulation results using real transistor model parameters ALA400 are also included to confirm the theory.
Goff, J.; Swartz, J. M.; Gulick, S. P. S.
2017-12-01
Barrier islands provide critical support and protection for coastal communities and ecosystems, but are potentially vulnerable to net losses of sand during major storms. Evidence from satellite imagery, ground observations and tide stations indicates that Hurricane Harvey in 2017 caused a large outflow event of waters moving from the bays out towards the sea in the Port Aransas, Texas region. Rather than just an ebb of a storm surge, this event may have been driven by seaward-directed winds on the left side of storm. Less than a month after landfall, we conducted a swath mapping and sampling survey in Lydia Ann Channel and Aransas Pass, where we had earlier mapped in 2009 and 2012 as part of the UT marine geology and geophysical field course. These waterways are important conduits linking Corpus Christi and Aransas bays to the Gulf of Mexico. This multi-year record allows us to gauge the impact of the outflow event on these waterways in the context of "normal" coastal processes. Both satellite imagery and sonar mapping reveal that the outflow event caused significant erosion, both on land and beneath the water, along the edges of Lydia Ann Channel and Corpus Christi ship channel. It also caused seaward-directed flow and erosion through breaches in the foredunes along southern San Jose Island, from waters that overtopped Lydia Ann Channel. Much of the sand that was transported seaward settled in Lydia Ann Channel and Aransas Pass (up to 6.5 m accumulation), possibly during the waning stages of the event. However, a likely large (but unknown) quantity of barrier and estuarine sand could have been transported well out to sea, beyond the jetties, at the peak of the event. If so, it would have resulted in a net loss of sand from the barrier island system.
Intestinal permeability of forskolin by in situ single pass perfusion in rats.
Liu, Zhen-Jun; Jiang, Dong-bo; Tian, Lu-Lu; Yin, Jia-Jun; Huang, Jian-Ming; Weng, Wei-Yu
2012-05-01
The intestinal permeability of forskolin was investigated using a single pass intestinal perfusion (SPIP) technique in rats. SPIP was performed in different intestinal segments (duodenum, jejunum, ileum, and colon) with three concentrations of forskolin (11.90, 29.75, and 59.90 µg/mL). The investigations of adsorption and stability were performed to ensure that the disappearance of forskolin from the perfusate was due to intestinal absorption. The results of the SPIP study indicated that forskolin could be absorbed in all segments of the intestine. The effective permeability (P (eff)) of forskolin was in the range of drugs with high intestinal permeability. The P (eff) was highest in the duodenum as compared to other intestinal segments. The decreases of P (eff) in the duodenum and ileum at the highest forskolin concentration suggested a saturable transport process. The addition of verapamil, a P-glycoprotein inhibitor, significantly enhanced the permeability of forskolin across the rat jejunum. The absorbed fraction of dissolved forskolin after oral administration in humans was estimated to be 100 % calculated from rat P (eff). In conclusion, dissolved forskolin can be absorbed readily in the intestine. The low aqueous solubility of forskolin might be a crucial factor for its poor oral bioavailability. © Georg Thieme Verlag KG Stuttgart · New York.
Jay, Anne E.; Marsh, Julian S.; Fluteau, Frédéric; Courtillot, Vincent
2018-02-01
Physical volcanological features are presented for a 710-m-thick section, of the Naude's Nek Pass, within the lower part of the Lesotho remnant of the Karoo Large Igneous Province. The section consists of inflated pāhoehoe lava with thin, impersistent sedimentary interbeds towards the base. There are seven discreet packages of compound and hummocky pāhoehoe lobes containing flow-lobe tumuli, making up approximately 50% of the section. Approximately 45% of the sequence consists of 14 sheet lobes, between 10 and 52-m-thick. The majority of the sheet lobes are in two packages indicating prolonged periods of lava supply capable of producing thick sheet lobes. The other sheet lobes are as individual lobes or pairs, within compound flows, suggesting brief increases in lava supply rate. We suggest, contrary to current belief, that there is no evidence that compound flows are proximal to source and sheet lobes (simple flows) are distal to source and we propose that the presence of flow-lobe tumuli in compound flows could be an indicator that a flow is distal to source. We use detailed, previously published, studies of the Thakurvadi Formation (Deccan Traps) as an example. We show that the length of a lobe and therefore the sections that are `medial or distal to source' are specific to each individual lobe and are dependent on the lava supply of each eruptive event, and as such flow lobe tumuli can be used as an indicator of relative distance from source.
Single inclusive spectra, Hanburg–Brown–Twiss and elliptic flow: A ...
Indian Academy of Sciences (India)
The constraints due to the measurements of the single particle inclusive spectra, the ... flow and HBT vs. the reaction plane with a hydro-motivated blast wave model. .... different mass particles allows the extraction of the elliptic component of the transverse ... Moreover, the details of the dependence of elliptic flow on particle.
Three-dimensional numerical modeling of turbulent single-phase and two-phase flow in curved pipes
International Nuclear Information System (INIS)
Xin, R.C.; Dong, Z.F.; Ebadian, M.A.
1996-01-01
In this study, three-dimensional single-phase and two-phase flows in curved pipes have been investigated numerically. Two different pipe configurations were computed. When the results of the single-phase flow simulation were compared with the experimental data, a fairly good agreement was achieved. A flow-developing process has been suggested in single-phase flow, in which the turbulence is stronger near the outer tube wall than near the inner tube wall. For two-phase flow, the Eulerian multiphase model was used to simulate the phase distribution of a three-dimensional gas-liquid bubble flow in curved pipe. The RNG/κ-ε turbulence model was used to determine the turbulence field. An inlet gas void fraction of 5 percent was simulated. The gas phase effects on the liquid phase flow velocity have been examined by comparing the results of single-phase flow and two-phase flow. The findings show that for the downward flow in the U bend, the gas concentrates at the inner portion of the cross section at φ = π/18 - π/6 in most cases. The results of the phase distribution simulation are compared to experimental observations qualitatively and topologically
Numerical Simulation Of Flow Through An Artificial Heart
Rogers, Stuart; Kutler, Paul; Kwak, Dochan; Kiris, Centin
1991-01-01
Research in both artificial hearts and fluid dynamics benefits from computational studies. Algorithm that implements Navier-Stokes equations of flow extended to simulate flow of viscous, incompressible blood through articifial heart. Ability to compute details of such flow important for two reasons: internal flows with moving boundaries of academic interest in their own right, and many of deficiencies of artificial hearts attributable to dynamics of flow.
Reverse flow through a large scale multichannel nozzle
International Nuclear Information System (INIS)
Duignan, M.R.; Nash, C.A.
1992-01-01
A database was developed for the flow of water through a scaled nozzle of a Savannah River Site reactor inlet plenum. The water flow in the nozzle was such that it ranged from stratified to water solid conditions. Data on the entry of air into the nozzle and plenum as a function of water flow are of interest in loss-of-coolant studies. The scaled nozzle was 44 cm long, had an entrance diameter of 95 mm, an exit opening of 58 mm x 356 mm, and an exit hydraulic diameter approximately equal to that of the inlet. Within the nozzle were three flow-straightening vanes which divided the flow path into four channels. All data were taken at steady-state and isothermal (300 K ± 1.5 K) conditions. During the reverse flow of water through the nozzle the point at which air begins to enter was predicted within 90% by a critical weir-flow calculation. The point of air entry into the plenum itself was found to be a function of flow conditions
Energy and exergy analysis of a two pass photovoltaic –thermal (PV/T) air heater
Energy Technology Data Exchange (ETDEWEB)
Srinivas, M.; Jayaraj, S. [Department of Mechanical Engineering, National Institute of Technology, Calicut-673601 (India)
2013-07-01
A double pass hybrid solar air (PV/T) heater with slats is designed and fabricated to study elaborately its thermal and electrical performance corresponding to the warm and humid environment. Air as a heat removing fluid is made to flow through upper and lower channels of the collector. The collector is designed in such way that the absorber plate is partially covered by solar cells. Thin metallic strips (called slats) are attached longitudinally at the bottom side of the absorber plate to improve the overall system performance (by increasing the cooling rate of the absorber plate). Thermal and electrical performances of the whole system at different cooling rates are presented. The exergy analysis of double pass hybrid solar air (PV/T) heater with slats has also been carried out. The instantaneous overall energy and overall exergy efficiency of the double pass hybrid (PV/T) solar air heater varies between 29 – 37 percent and 14-17 percent respectively. These obtained values are comparable with that of published results.
Directory of Open Access Journals (Sweden)
Cheng-Ying Tsai
2018-06-01
Full Text Available It has been well known that the resonant interaction of an ultrarelativistic electron beam and the radiation field in the single-pass high-gain free electron laser (FEL amplifier leads to the optical gain guiding. The transverse Laplacian term of the slowly varying wave equation in the linear regime can be approximated as a constant detuning parameter, i.e., |∇_{⊥}^{2}|∼k_{R}/z_{R} where k_{R} is the resonant wave number and z_{R} is the Rayleigh range of the laser. In the post-saturation regime, the radiation power begins to oscillate about an equilibrium for the untapered case while continues to grow by undulator tapering. Moreover, in this regime the gain guiding decreases and the simple constant detune is no longer valid. In this paper we study the single-pass high-gain FEL performance in the post-saturation regime with inclusion of diffraction effect and undulator tapering. Our analysis relies upon two constants of motion, one from the energy conservation and the other from the adiabatic invariant of the action variable. By constructing a two-dimensional axisymmetric wave equation and the coupled one-dimensional electron dynamical equations, the performance of a tapered FEL in the postsaturation regime can be analyzed, including the fundamental mode profile, the power efficiency and the scaled energy spread. We begin the analytical investigation with two different axisymmetric electron beam profiles, the uniform and bounded parabolic ones. It is found that the tapered FEL power efficiency can be smaller but close to the taper ratio provided the resonant phase remains constant and the beam-wave is properly matched. Such a tapered efficiency is nearly independent of transverse electron beam size before significant electron detrapping occurs. This is essentially different from the untapered case, where the power extraction efficiency is around the essential FEL gain bandwidth (or ρ, the Pierce or FEL parameter and depends on the beam
Gabersek, Sasa.; Durran, Dale R.
2004-12-01
Gap winds produced by a uniform airstream flowing over an isolated flat-top ridge cut by a straight narrow gap are investigated by numerical simulation. On the scale of the entire barrier, the proportion of the oncoming flow that passes through the gap is relatively independent of the nondimensional mountain height , even over that range of for which there is the previously documented transition from a “flow over the ridge” regime to a “flow around” regime.The kinematics and dynamics of the gap flow itself were investigated by examining mass and momentum budgets for control volumes at the entrance, central, and exit regions of the gap. These analyses suggest three basic behaviors: the linear regime (small ) in which there is essentially no enhancement of the gap flow; the mountain wave regime ( 1.5) in which vertical mass and momentum fluxes play a crucial role in creating very strong winds near the exit of the gap; and the upstream-blocking regime ( 5) in which lateral convergence generates the strongest winds near the entrance of the gap.Trajectory analysis of the flow in the strongest events, the mountain wave events, confirms the importance of net subsidence in creating high wind speeds. Neglect of vertical motion in applications of Bernoulli's equation to gap flows is shown to lead to unreasonable wind speed predictions whenever the temperature at the gap exit exceeds that at the gap entrance. The distribution of the Bernoulli function on an isentropic surface shows a correspondence between regions of high Bernoulli function and high wind speeds in the gap-exit jet similar to that previously documented for shallow-water flow.
Effect of wall thickness and helium cooling channels on duct magnetohydrodynamic flows
International Nuclear Information System (INIS)
He, Qingyun; Feng, Jingchao; Chen, Hongli
2016-01-01
Highlights: • MHD flows in ducts of different wall thickness compared with wall uniform. • Study of velocity, pressure distribution in ducts MHD flows with single pass of helium cooling channels. • Comparison of three types of dual helium cooling channels and acquisition of an option for minimum pressure drop. • A single short duct MHD flow in blanket without FCI has been simulated for pressure gradient analysis. - Abstract: The concept of dual coolant liquid metal (LM) blanket has been proposed in different countries to demonstrate the technical feasibility of DEMO reactor. In the system, helium gas and PbLi eutectic, separated by structure grid, are used to cool main structure materials and to be self-cooled, respectively. The non-uniform wall thickness of structure materials gives rise to wall non-homogeneous conductance ratio. It will lead to electric current distribution changes, resulting in significant changes in the velocity distribution and pressure drop of magnetohydrodynamic (MHD) flows. In order to investigate the effect of helium channels on MHD flows, different methods of numerical simulations cases are carried out including the cases of different wall thicknesses, single pass of helium cooling channels, and three types of dual helium cooling channels. The results showed that helium tubes are able to affect the velocity distribution in the boundary layer by forming wave sharp which transfers from Hartmann boundary layer to the core area. In addition, the potential profile and pressure drop in the cases have been compared to these in the case of walls without cooling channel, and the pressure gradient of a simplified single short duct MHD flow in blanket shows small waver along the central axis in the helium channel position.
Effect of wall thickness and helium cooling channels on duct magnetohydrodynamic flows
Energy Technology Data Exchange (ETDEWEB)
He, Qingyun; Feng, Jingchao; Chen, Hongli, E-mail: hlchen1@ustc.edu.cn
2016-02-15
Highlights: • MHD flows in ducts of different wall thickness compared with wall uniform. • Study of velocity, pressure distribution in ducts MHD flows with single pass of helium cooling channels. • Comparison of three types of dual helium cooling channels and acquisition of an option for minimum pressure drop. • A single short duct MHD flow in blanket without FCI has been simulated for pressure gradient analysis. - Abstract: The concept of dual coolant liquid metal (LM) blanket has been proposed in different countries to demonstrate the technical feasibility of DEMO reactor. In the system, helium gas and PbLi eutectic, separated by structure grid, are used to cool main structure materials and to be self-cooled, respectively. The non-uniform wall thickness of structure materials gives rise to wall non-homogeneous conductance ratio. It will lead to electric current distribution changes, resulting in significant changes in the velocity distribution and pressure drop of magnetohydrodynamic (MHD) flows. In order to investigate the effect of helium channels on MHD flows, different methods of numerical simulations cases are carried out including the cases of different wall thicknesses, single pass of helium cooling channels, and three types of dual helium cooling channels. The results showed that helium tubes are able to affect the velocity distribution in the boundary layer by forming wave sharp which transfers from Hartmann boundary layer to the core area. In addition, the potential profile and pressure drop in the cases have been compared to these in the case of walls without cooling channel, and the pressure gradient of a simplified single short duct MHD flow in blanket shows small waver along the central axis in the helium channel position.
Message Passing Framework for Globally Interconnected Clusters
International Nuclear Information System (INIS)
Hafeez, M; Riaz, N; Asghar, S; Malik, U A; Rehman, A
2011-01-01
In prevailing technology trends it is apparent that the network requirements and technologies will advance in future. Therefore the need of High Performance Computing (HPC) based implementation for interconnecting clusters is comprehensible for scalability of clusters. Grid computing provides global infrastructure of interconnecting clusters consisting of dispersed computing resources over Internet. On the other hand the leading model for HPC programming is Message Passing Interface (MPI). As compared to Grid computing, MPI is better suited for solving most of the complex computational problems. MPI itself is restricted to a single cluster. It does not support message passing over the internet to use the computing resources of different clusters in an optimal way. We propose a model that provides message passing capabilities between parallel applications over the internet. The proposed model is based on Architecture for Java Universal Message Passing (A-JUMP) framework and Enterprise Service Bus (ESB) named as High Performance Computing Bus. The HPC Bus is built using ActiveMQ. HPC Bus is responsible for communication and message passing in an asynchronous manner. Asynchronous mode of communication offers an assurance for message delivery as well as a fault tolerance mechanism for message passing. The idea presented in this paper effectively utilizes wide-area intercluster networks. It also provides scheduling, dynamic resource discovery and allocation, and sub-clustering of resources for different jobs. Performance analysis and comparison study of the proposed framework with P2P-MPI are also presented in this paper.
Propagation of atmospheric pressure helium plasma jet into ambient air at laminar gas flow
Pinchuk, M.; Stepanova, O.; Kurakina, N.; Spodobin, V.
2017-05-01
The formation of an atmospheric pressure plasma jet (APPJ) in a gas flow passing through the discharge gap depends on both gas-dynamic properties and electrophysical parameters of the plasma jet generator. The paper presents the results of experimental and numerical study of the propagation of the APPJ in a laminar flow of helium. A dielectric-barrier discharge (DBD) generated inside a quartz tube equipped with a coaxial electrode system, which provided gas passing through it, served as a plasma source. The transition of the laminar regime of gas flow into turbulent one was controlled by the photography of a formed plasma jet. The corresponding gas outlet velocity and Reynolds numbers were revealed experimentally and were used to simulate gas dynamics with OpenFOAM software. The data of the numerical simulation suggest that the length of plasma jet at the unvarying electrophysical parameters of DBD strongly depends on the mole fraction of ambient air in a helium flow, which is established along the direction of gas flow.
Lim, Y.; Kim, W.
2015-12-01
Meandering rivers are extremely ubiquitous on Earth, yet it is only recently that single-thread experimental channels with low sinuosity have been created. In these recent experiments, as well as in natural rivers, vegetation plays a crucial role in maintaining a meandering pattern by adding cohesion to the bank and inhibiting erosion. The ancient, highly sinuous channels found on Mars are enigmatic because presumably vegetation did not exist on ancient Mars. Under the hypothesis that Martian meandering rivers formed by chemical precipitation on levees and flood plain deposits, we conducted carbonate flume experiments to investigate the formation and evolution of a single-thread meander pattern without vegetation. The flow recirculating in the flume is designed to accelerate chemical reactions - dissolution of limestone using CO2 gas to produce artificial spring water and precipitation of carbonates to increase cohesion- with precise control of water discharge, sediment discharge, and temperature. Preliminary experiments successfully created a single-thread meandering pattern through chemical processes. Carbonate deposits focused along the channel sides improved the bank stability and made them resistant to erosion, which led to a stream confined in a narrow path. The experimental channels showed lateral migration of the bend through cut bank and point bar deposits; intermittent floods created overbank flow and encouraged cut bank erosion, which enhanced lateral migration of the channel, while increase in sediment supply improved lateral point bar deposition, which balanced erosion and deposition rates. This mechanism may be applied to terrestrial single-thread and/or meandering rivers with little to no vegetation or before its introduction to Earth and also provide the link between meandering river records on Mars to changes in Martian surface conditions.
Sand transport in a two pass internal cooling duct with rib turbulators
International Nuclear Information System (INIS)
Singh, Sukhjinder; Tafti, Danesh; Reagle, Colin; Delimont, Jacob; Ng, Wing; Ekkad, Srinath
2014-01-01
Highlights: • Highest particle impingement observed in the bend and first quarter of 2nd pass. • Average particle impingement per pitch is 28% higher in the second pass. • Rib faces are by far the most susceptible to particle impingement. • Particle impingement is sensitive to particle size. • Particle impingement is sensitive to wall collision model used. - Abstract: Jet engines often operate under dirty conditions where large amounts of particulate matter can be ingested, especially, sand, ash and dirt. Particulate matter in different engine components can lead to degradation in performance. The focus of this study is to investigate the sand transport and deposition in the internal cooling passages of turbine blades. A two pass stationary square duct with rib turbulators subjected to sand ingestion is studied using Large Eddy Simulations (LES). Each pass has ribs on two opposite walls and aligned normal to the main flow direction. The rib pitch to rib height (P/e) is 9.28, the rib height to channel hydraulic diameter (e/D h ) is 0.0625 and calculations have been carried out for a bulk Reynolds number of 25,000. Particle sizes in the range 0.5–25 μm are considered, with the same size distribution as found in Arizona Road Dust (medium). Large Eddy Simulation (LES) with a wall-model is used to model the flow and sand particles are modeled using a discrete Lagrangian framework. Results quantify the distribution of particle impingement density on all surfaces. Highest particle impingement density is found in the first quarter section of the second pass after the 180° turn, where the recorded impingement is more than twice that of any other region. It is also found that the average particle impingement per pitch is 28% higher in the second pass than the first pass. Results show lower particle tendency to impact the region immediately behind the rib in the first pass compared to the second pass where particle impingement is more uniform in the region
Transport of synthetic colloids through single saturated fractures: A literature review
International Nuclear Information System (INIS)
Reimus, P.W.
1995-07-01
Colloids having the same surface charge sign as the bulk of the geologic media in a groundwater system may be able to travel through the system faster than soluble species because they will follow fluid streamlines more closely and they should have less tendency to diffuse into pores or dead spaces in the media than soluble species. Synthetic colloids with uniform, controlled properties may be ideal for serving as open-quotes worst-caseclose quotes tracers that provide lower-bound estimates of contaminant travel times in hydrologic systems. This report discusses a review of the literature pertaining to colloid transport in single saturated natural fractures. After a brief background discussion to put the literature review in perspective, the phenomenon of colloid transport in saturated fractures is divided into three major topics, each of which is reviewed in detail: (1) saturated fluid flow through fractures; (2) colloid transport by convection, diffusion, and force fields; and (3) colloid interactions with surfaces. It is suggested that these phenomena be accounted for in colloid transport models by using (1) lubrication theory to describe water flow through fractures, (2) particle tracking methods to describe colloid transport in fractures, and (3) a kinetic boundary layer approximation to describe colloid interactions with fracture walls. These methods offer better computational efficiency and better experimental accessibility to model parameters than rigorously solving the complete governing equations
2010-01-01
... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Carcasses of livestock condemned on... DISPOSAL OF CONDEMNED OR OTHER INEDIBLE PRODUCTS AT OFFICIAL ESTABLISHMENTS § 314.7 Carcasses of livestock condemned on ante-mortem inspection not to pass through edible product areas. Carcasses of livestock which...
Laser doppler anemometry in single- and two-phase flows
International Nuclear Information System (INIS)
Durst, F.
1976-01-01
The present report gives an introduction into laser-Doppler anemometry and tries to explain the basic physical principles of this measuring technique. Moire fringe patterns are used in order to visually model LDA-signals and to explain the basic difference in optical systems. It is pointed out that LDA measurements in highly turbulent flows and in two-phase flows should be attempted with direction sensitive instruments only. Some of the optical systems developed by the author and his collaborators are introduced and their functioning in measurements is demonstrated. These measurements embrace investigations in a number of single-phase flows including flames. (orig.) [de
Clogging transition of many-particle systems flowing through bottlenecks
Zuriguel, Iker; Parisi, Daniel Ricardo; Hidalgo, Raúl Cruz; Lozano, Celia; Janda, Alvaro; Gago, Paula Alejandra; Peralta, Juan Pablo; Ferrer, Luis Miguel; Pugnaloni, Luis Ariel; Clément, Eric; Maza, Diego; Pagonabarraga, Ignacio; Garcimartín, Angel
2014-12-01
When a large set of discrete bodies passes through a bottleneck, the flow may become intermittent due to the development of clogs that obstruct the constriction. Clogging is observed, for instance, in colloidal suspensions, granular materials and crowd swarming, where consequences may be dramatic. Despite its ubiquity, a general framework embracing research in such a wide variety of scenarios is still lacking. We show that in systems of very different nature and scale -including sheep herds, pedestrian crowds, assemblies of grains, and colloids- the probability distribution of time lapses between the passages of consecutive bodies exhibits a power-law tail with an exponent that depends on the system condition. Consequently, we identify the transition to clogging in terms of the divergence of the average time lapse. Such a unified description allows us to put forward a qualitative clogging state diagram whose most conspicuous feature is the presence of a length scale qualitatively related to the presence of a finite size orifice. This approach helps to understand paradoxical phenomena, such as the faster-is-slower effect predicted for pedestrians evacuating a room and might become a starting point for researchers working in a wide variety of situations where clogging represents a hindrance.
Calculation of incompressible fluid flow through cambered blades
Hsu, C. C.
1970-01-01
Conformal mapping technique yields linear, approximate solutions for calculating flow of an incompressible fluid through staggered array of cambered blades for the cases of flow with partial cavitation and supercavitation. Lift and drag coefficients, cavitation number, cavity shape, and exit flow conditions can be determined.
Trends in the use of flow-through shares
International Nuclear Information System (INIS)
Jennings, R. G.
1998-01-01
Flow-through shares financing is considered the most cost effective equity-based financing option for non-tax-paying exploration companies, a form of financing that has helped a very large number of resource-based companies start, stay alive and grow in a very competitive financial marketplace. This paper provides a brief historical review of the flow-though shares concept, outlines developments in recent legislation, changes in the Income Tax Act, and trends in financial structures, and reviews flow-through shares from a tax perspective of the investor and the issuer
A Study of Heat Transfer and Flow Characteristics of Rising Taylor Bubbles
Scammell, Alexander David
2016-01-01
Practical application of flow boiling to ground- and space-based thermal management systems hinges on the ability to predict the systems heat removal capabilities under expected operating conditions. Research in this field has shown that the heat transfer coefficient within two-phase heat exchangers can be largely dependent on the experienced flow regime. This finding has inspired an effort to develop mechanistic heat transfer models for each flow pattern which are likely to outperform traditional empirical correlations. As a contribution to the effort, this work aimed to identify the heat transfer mechanisms for the slug flow regime through analysis of individual Taylor bubbles.An experimental apparatus was developed to inject single vapor Taylor bubbles into co-currently flowing liquid HFE 7100. The heat transfer was measured as the bubble rose through a 6 mm inner diameter heated tube using an infrared thermography technique. High-speed flow visualization was obtained and the bubble film thickness measured in an adiabatic section. Experiments were conducted at various liquid mass fluxes (43-200 kgm2s) and gravity levels (0.01g-1.8g) to characterize the effect of bubble drift velocityon the heat transfer mechanisms. Variable gravity testing was conducted during a NASA parabolic flight campaign.Results from the experiments showed that the drift velocity strongly affects the hydrodynamics and heat transfer of single elongated bubbles. At low gravity levels, bubbles exhibited shapes characteristic of capillary flows and the heat transfer enhancement due to the bubble was dominated by conduction through the thin film. At moderate to high gravity, traditional Taylor bubbles provided small values of enhancement within the film, but large peaks in the wake heat transfer occurred due to turbulent vortices induced by the film plunging into the trailing liquid slug. Characteristics of the wake heat transfer profiles were analyzed and related to the predicted velocity field
Flow-through shares for power development
International Nuclear Information System (INIS)
Howie, K.D.
1999-01-01
Financial advantages will occur to power producers in Ontario provided that they are innovative in raising capital needed to take advantage of opportunities offered by the Energy Competition Act of 1998. In the new electricity regime, the availability of long term non-recourse debt financing supported by long term power purchasing from Ontario Hydro will probably decrease. The issuance of flow-through shares is a form of financing that could by available to them for certain projects, and there is the probability that greater equity financing will be needed. These flow-through shares can give investors immediate tax savings, a potential favorable return on their equity investment, and a means of financing certain kinds of power projects
Gas and Oil Flow through Wellbore Flaws
Hatambeigi, M.; Anwar, I.; Reda Taha, M.; Bettin, G.; Chojnicki, K. N.; Stormont, J.
2017-12-01
We have measured gas and oil flow through laboratory samples that represent two important potential flow paths in wellbores associated with the Strategic Petroleum Reserve (SPR): cement-steel interfaces (microannuli) and cement fractures. Cement fractures were created by tensile splitting of cement cores. Samples to represent microannuli were created by placing thin steel sheets within split cement cores so flow is channeled along the cement-steel interface. The test sequence included alternating gas and oil flow measurements. The test fluids were nitrogen and silicone oil with properties similar to a typical crude oil stored in the SPR. After correcting for non-linear (inertial) flow when necessary, flows were interpreted as effective permeability and hydraulic aperture using the cubic law. For both samples with cement fractures and those with cement-steel interfaces, initial gas and oil permeabilities were comparable. Once saturated with oil, a displacement pressure had to be overcome to establish gas flow through a sample, and the subsequent gas permeability were reduced by more than 50% compared to its initial value. Keywords: wellbore integrity, leakage, fracture, microannulus, SPR. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of NTESS/Honeywell, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2017-8168 A
Sustained-Paced Finger Tapping: A Novel Approach to Measure Internal Sustained Attention
Directory of Open Access Journals (Sweden)
Marco A. Petilli
2018-05-01
Full Text Available Sustained attention is a fundamental prerequisite for all cognitive functions and its impairment is a common aftermath of both developmental and acquired neurological disorders. To date, all the sustained attention tasks rely heavily on selective attention to external stimuli. The interaction between selective and sustained attention represents a limit in the field of assessment and may mislead researchers or distort conclusions. The aim of the present perspective study was to propose a sustained version of the Paced Finger Tapping (S-PFT test as a novel approach to measure sustained attention that does not leverage external stimuli. Here, we administered S-PFT and other attentional tasks (visual sustained attention, visuospatial attention capacity, selective attention, and divided attention tasks to 85 adolescents. Thus, we provide evidence suggesting that S-PFT is effective in causing performance decrement over time, an important trademark of sustained attention tasks. We also present descriptive statistics showing the relationship between S-PFT and the other attentional tasks. These analyses show that, unlike visual sustained attention tests, performances to our task of internal sustained attention were not correlated to measures of selective attention and visuospatial attention capacity. Our results suggest that S-PFT could represent a promising and alternative tool both for empirical research and clinical assessment of sustained attention.
Instrument for real-time pulse-shape analysis of slit-scan flow cytometry signals
van Oven, C.; Aten, J. A.
1990-01-01
An instrument is described which analyses shapes of fluorescence profiles generated by particles passing through the focussed laser beam of a flow cytometer. The output signal of this pulse-shape analyzer is used as input for the signal processing electronics of a commercial flow cytometer system.
Surface effects in the energy loss of ions passing through a thin foil
International Nuclear Information System (INIS)
Osma, J.; Garcia de Abajo, F.J.
1997-01-01
The role of surface plasmon excitation in the interaction of ions passing through thin films has been studied in both the Bloch hydrodynamic approximation and the local response approach for projectile velocities above the maximum of the stopping power curve. The effect of the surface is found to be much weaker when the dispersion of the modes is taken into consideration than in the case of nondispersive media, though qualitatively the main features of the hydrodynamic approach resemble those of the local one. A generalization of the Bothe-Landau convolution formula for the loss probability distribution is derived to take into account the scattering due to the surface. The effects of the surface in the energy-loss spectra are discussed. A comparison with experiment is given. copyright 1997 The American Physical Society
International Nuclear Information System (INIS)
Shcherbakov, S.; Sergeev, V.
2011-01-01
The results obtained using the TURBOFLOW computer code are presented for the numerical calculations of space distributions of coolant flow, heating and boiling characteristics in WWER fuel assemblies with regard to the effect of mixing grids of 'Swirler' and 'Run-through' types installed in FA on the above processes. The nature of the effect of these grids on coolant flow was demonstrated to be different. Thus, the relaxation length of cross flows after passing a 'Run-through' grid is five times as compared to a 'Swirler'-type grid, which correlates well with the experimental data. At the same time, accelerations occurring in the flow downstream of a 'Swirler'-type grid are by an order of magnitude greater than those after a 'Run-through' grid. As a result, the efficiency of one-phase coolant mixing is much higher for the grids of 'Run-through' type, while the efficiency of steam removal from fuel surface is much higher for 'Swirler'-type grids. To achieve optimal removal of steam from fuel surface it has been proposed to install into fuel assemblies two 'Swirler'-type grids in tandem at a distance of about 10 cm from each other with flow swirling in opposite directions. 'Run-through' grids would be appropriate for use for mixing in fuel assemblies with a high non-uniformity of fuel-by-fuel power generation. (authors)
Guneratne Banda Wickremasinghe; Param Silvapulle
2004-01-01
This paper investigates the effect of exchange rate volatility on the degree of exchange rate pass-through in Japan for the period January 1975 to June 1997. Although several studies put forward theoretical arguments for the volatility-domestic import price relationship, only a very few studies produced empirical evidence. The volatility of contractual currency based exchange rate index returns was modelled using GARCH-type processes with skewed student t-distribution, capturing the typical n...
The coma cluster after lunch: Has a galaxcy group passed through the cluster core?
Burns, Jack O.; Roettiger, Kurt; Ledlow, Michael; Klypin, Anatoly
1994-01-01
We propose that the Coma cluster has recently undergone a collision with the NGC 4839 galaxy group. The ROSAT X-ray morphology, the Coma radio halo, the presence of poststarburst galaxies in the bridge between Coma and NGC 4839, the usually high velocity dispersion for the NGC 4839 group, and the position of a large-scale galaxy filament to the NE of Coma are all used to argue that the NGC 4839 group passed through the core of Coma approximately 2 Gyr ago. We present a new Hydro/N-body simulation of the merger between a galaxy group and a rich cluster that reproduces many of the observed X-ray and optical properties of Coma/NGC 4839.
International Nuclear Information System (INIS)
Bourke, P.J.; Rae, J.
1981-01-01
A multi-packer technique was used to locate twelve discrete fractures in the lower half of a 200 m deep drill hole in Cornish granite. The resistances to water flows into these fractures both singly and together were measured. Geological explanations of the results obtained were sought by examination of core from the hole. Analysis of the results and the further data needed and now being sought to determine resistance to flow over long distances through the pattern of interconnected fractures are discussed. This information is required for the assessment of the safety of burial of radioactive wastes
International Nuclear Information System (INIS)
Yun, B.J.; Kang, K.H.; Euh, D.J.; Song, C.H.; Baek, W.P.
2005-01-01
Full text of publication follows: A new type instrumentation, average bidirectional flow tube, was suggested to apply to the single and two phase flow condition. Its working principle is similar to that of the Pitot tube. The pressure measured at the front of the flow tube is equal to the total pressure, while that measured at the rear tube is slightly less than static pressure of flow field due to the suction effect at the downstream. It gives an amplification effect of measured pressure difference at the flow tube. The proposed instrumentation has the characteristics that it could be applicable to low flow condition and measure bidirectional flow. It was tested in the air-water vertical and horizontal test sections which have 0.08 m inner diameter. The pressure difference across the average bidirectional flow tube, system pressure, average void fraction and injection phasic mass flow rates were measured on the measuring plane. Test was performed primarily in the single phase water and air flow condition to get the amplification factor k of the flow tube. The test was also performed in the air-water two phase flow condition and the covered flow regimes were bubbly, slug, churn turbulent flow in the vertical pipe and stratified flow in the horizontal pipe. In order to calculate the phasic and total mass flow rates from the measured differential pressure, Chexal drift-flux correlation and momentum exchange factor between the two phases were introduced. The test result shows that the suggested instrumentation with the measured void fraction, Chexal drift-flux correlation and Bosio and Malnes' momentum exchange model can predict the phasic mass flow rates within 15% error compared to the true values. A new momentum exchange model was also suggested and it gives up to 5% improvement of the measured mass flow rate compared to combination of Bosio and Malnes' momentum exchange model. (authors)
Kuznetsova, T. A.
2018-05-01
The methods for increasing gas-turbine aircraft engines' (GTE) adaptive properties to interference based on empowerment of automatic control systems (ACS) are analyzed. The flow pulsation in suction and a discharge line of the compressor, which may cause the stall, are considered as the interference. The algorithmic solution to the problem of GTE pre-stall modes’ control adapted to stability boundary is proposed. The aim of the study is to develop the band-pass filtering algorithms to provide the detection functions of the compressor pre-stall modes for ACS GTE. The characteristic feature of pre-stall effect is the increase of pressure pulsation amplitude over the impeller at the multiples of the rotor’ frequencies. The used method is based on a band-pass filter combining low-pass and high-pass digital filters. The impulse response of the high-pass filter is determined through a known low-pass filter impulse response by spectral inversion. The resulting transfer function of the second order band-pass filter (BPF) corresponds to a stable system. The two circuit implementations of BPF are synthesized. Designed band-pass filtering algorithms were tested in MATLAB environment. Comparative analysis of amplitude-frequency response of proposed implementation allows choosing the BPF scheme providing the best quality of filtration. The BPF reaction to the periodic sinusoidal signal, simulating the experimentally obtained pressure pulsation function in the pre-stall mode, was considered. The results of model experiment demonstrated the effectiveness of applying band-pass filtering algorithms as part of ACS to identify the pre-stall mode of the compressor for detection of pressure fluctuations’ peaks, characterizing the compressor’s approach to the stability boundary.
Saturation flow mathematical model based on multiple combinations of lane groups
Energy Technology Data Exchange (ETDEWEB)
Racila, L.
2016-07-01
The ideal value of the traffic stream that can pass through an intersection is known as the saturation flow rate per hour on vehicle green time. The saturation flow is important in the understanding of the traffic light cycle and from there the understanding the Level of Service. The paper wishes to evaluate through a series of applied mathematical methods the effect of different lane grouping and critical lane group concept on the saturation flow rate. The importance of this method is that it creates a base for a signalized intersections timing plan. (Author)
Percutaneous penetration of 2-phenoxyethanol through rat and human skin.
Roper, C S; Howes, D; Blain, P G; Williams, F M
1997-01-01
2-Phenoxyethanol applied in methanol was absorbed (64 +/- 4.4% at 24 hr) through unoccluded rat skin in vitro in the static diffusion cell with ethanol/water as receptor fluid. By comparison (43 +/- 3.7% in 24 hr) was absorbed in the flow-through diffusion system with tissue culture medium as receptor fluid. 2-Phenoxyethanol applied in methanol was absorbed (59.3 +/- 7.0% at 6 hr) through unoccluded human skin in vitro in the flow-through diffusion cell with tissue culture medium. With both unoccluded cells, 2-phenoxyethanol was lost by evaporation but occlusion of the static cell reduced evaporation and increased total absorption to 98.8 +/- 7.0%. Skin, post mitochondrial fraction, metabolized phenoxyethanol to phenoxyacetic acid at 5% of the rate for liver. Metabolism was inhibited by 1 mM pyrazole, suggesting involvement of alcohol dehydrogenase. However, first-pass metabolism of phenoxyethanol to phenoxyacetic acid was not detected during percutaneous penetration through viable rat skin in the flow-through system. First-pass metabolism in the skin does not therefore have an influence on systemic availability of dermally absorbed phenoxyethanol. These measures of phenoxyethanol absorption through rat and human skin in vitro agree well with those obtained previously in vivo.
Performance model of metallic concentric tube recuperator with counter flow arrangement
Energy Technology Data Exchange (ETDEWEB)
Sharma, Harshdeep [HIET, Department of Mechanical Engineering, Ghaziabad, Uttar Pradesh (India); Kumar, Anoop; Goel, Varun [NIT, Department of Mechanical Engineering, Hamirpur, Himachal Pradesh (India)
2010-03-15
A performance model for counter flow arrangement in concentric tube recuperator that can be used to utilize the waste heat in the temperature range of 900-1,400 C is presented. The arrangement consists of metallic tubular inner and outer concentric shell with a small annular gap between two concentric shells. Flue gases pass through the inner shell while air passes through the annular gap in the reverse direction (counter flow arrangement). The height of the recuperator is divided into elements and an energy balance is performed on each elemental height. Results give necessary information about surface, gas and air temperature distribution, and the influence of operating conditions on recuperator performance. The recuperative effectiveness is found to be increased with increasing inlet gas temperature and decreased with increasing fuel flow rate. The present model accounts for all heat transfer processes pertinent to a counterflow radiation recuperator and provide a valuable tool for performance considerations. (orig.)
Wind flow through shrouded wind turbines
2017-03-01
Aeroflow 5-hole probe, which took various measurements at multiple planes of each model. Flow visualization tests, including oil and tufts, were also...through an Aeroflow 5-hole probe, which took various measurements at multiple planes of each model. Flow visualization tests, including oil and tufts...facilities by 2025. This meets a larger DOD mandate, Title 10 USC § 2911, which directs at least 25 percent of any DOD facility’s energy consumption come
Study on flow rate measurement and visualization of helium-air exchange flow through a small opening
International Nuclear Information System (INIS)
Fumizawa, Motoo
1992-01-01
This paper deals with an experimental investigation on buoyancy-driven exchange flows through horizontal and inclined openings. The method of the mass increment was developed to measure the flow rate in helium-air system and a displacement fringe technique was adopted in Mach-Zehnder interferometer to visualize the flow. As the result, the followings were obtained: Flow visualization results indicate that the upward and downward plumes of helium and air break through the opening intermittently, and they swing in the lateral direction through the horizontal opening. It is clearly visualized that the exchange flows through the inclined openings take place smoothly and stably in the separated passages. The inclination angle for the maximum Froude number decreases with increasing length-to-diameter ratio in the helium-air system, on the contrary to Mercer's experimental results in the water-brine system indicating that the angle remains almost constant. (author)
Effects of water-channel attractions on single-file water permeation through nanochannels
International Nuclear Information System (INIS)
Xu, Yousheng; Zheng, Youqu; Tian, Xingling; Lv, Mei; He, Bing; Deng, Maolin; Xiu, Peng; Tu, Yusong
2016-01-01
Single-file transportation of water across narrow nanochannels such as carbon nanotubes has attracted much attention in recent years. Such permeation can be greatly affected by the water-channel interactions; despite some progress, this issue has not been fully explored. Herein we use molecular dynamics simulations to investigate the effects of water-channel attractions on occupancy, translational (transportation) and orientational dynamics of water inside narrow single-walled carbon nanotubes (SWNTs). We use SWNTs as the model nanochannels and change the strength of water-nanotube attractions to mimic the changes in the hydrophobicity/polarity of the nanochannel. We investigate the dependence of water occupancy inside SWNTs on the water-channel attraction and identify the corresponding threshold values for drying states, wetting-drying transition states, and stably wetting states. As the strength of water-channel attractions increases, water flow increases rapidly first, and then decreases gradually; the maximal flow occurs in the case where the nanochannel is predominately filled with the 1D water wire but with a small fraction of ‘empty states’, indicating that appropriate empty-filling (drying-wetting) switching can promote water permeation. This maximal flow is unexpected, since in traditional view, the stable and tight hydrogen-bonding network of the water wire is the prerequisite for high permeability of water. The underlying mechanism is discussed from an energetic perspective. In addition, the effect of water-channel attractions on reorientational dynamics of the water wire is studied, and a negative correlation between the flipping frequency of water wire and the water-channel attraction is observed. The underlying mechanism is interpreted in term of the axial total dipole moment of inner water molecules. This work would help to better understand the effects of water-channel attractions on wetting properties of narrow nanochannels, and on single
Evaluation of Core Bypass Flow in the Prismatic VHTR with a Multi-block Experiment
International Nuclear Information System (INIS)
Lee, Jeong Hun; Yoon, Su Jong; Park, Goon Cherl; Kim, Min Hwan
2010-01-01
The core of Prismatic Modular Reactor (PMR) consists of assemblies of hexagonal graphite fuel and reflector elements. The core bypass flow of Very High Temperature Reactor (VHTR) is defined as the core flow that does not pass through the coolant channels but passes through the bypass gap between fuel elements. The increase in bypass flow makes the decrease in effective coolant flow. Since the core bypass flow has a negative impact on safety and efficiency of VHTR, core bypass phenomena have to be investigated to improve the core thermal margin of VHTR. For this purpose, the international project, I-NERI project, has been carried out since 2008. I-NERI project is collaborative project that KAERI and SNU of Korea side and INL, ANL and TAMU of U.S side are involved. In order to evaluate the core bypass flow, the multicolumn and multi-layer experimental facility is designed by SNU. In this experiment, the effect of cross-flow and local variation of bypass gap on the bypass flow distribution is investigated. Furthermore, the experimental data will be used for validation of CFD code or thermal hydraulic analysis codes such as GAMMA or GAS-NET
Modelling of flow and contaminant migration in single rock fractures
International Nuclear Information System (INIS)
Dahlblom, P.; Joensson, L.
1990-03-01
The report deals with flow and hydrodynamic dispersion of a nonreactive contaminant in a single, irregularly shaped fracture. The main purpose of the report is to describe the basis and development of a computational 'tool' for simulating the aperture geometry of a single fracture and the detailed flow in it. On the basis of this flow information further properties of the fracture can be studied. Some initial application to dispersion of a nonreactive contaminant are thus discussed. The spatial pattern of variation of the fracture aperture is considered as a two-dimensional stochastic process. A method for simulation of such a process is described. The stochastic properties can be chosen arbitrarily. It is assumed that the fracture aperture belongs to a log-normal distribution. For calculation of the flow pattern, the Navier-Stokes equations are simplified to describe low velocity and steady-state flow. These equations, and the continuity equation are integrated in the direction across the fracture plane. A stream function, which describes the integrated flow in the fracture, is defined. A second order partial differential equation, with respect to the stream function, is established and solved by the finite difference method. Isolines for the stream function define boundaries between channels with equal flow rates. The travel time for each channel can be calculated to achieve a measure of the dispersion. The impact of the aperture distribution on the ratio between the mass balance fracture aperture and the cubic law fracture aperture is shown by simple examples. (28 figs., 1 tab., 22 refs.)
Brede, Jens; Atodiresei, Nicolae; Kuck, Stefan; Lazić, Predrag; Caciuc, Vasile; Morikawa, Yoshitada; Hoffmann, Germar; Blügel, Stefan; Wiesendanger, Roland
2010-07-23
We investigate the spin- and energy-dependent tunneling through a single organic molecule (CoPc) adsorbed on a ferromagnetic Fe thin film, spatially resolved by low-temperature spin-polarized scanning tunneling microscopy. Interestingly, the metal ion as well as the organic ligand show a significant spin dependence of tunneling current flow. State-of-the-art ab initio calculations including also van der Waals interactions reveal a strong hybridization of molecular orbitals and substrate 3d states. The molecule is anionic due to a transfer of one electron, resulting in a nonmagnetic (S=0) state. Nevertheless, tunneling through the molecule exhibits a pronounced spin dependence due to spin-split molecule-surface hybrid states.
Oil-in-water emulsions flow through constricted micro-capillarities
Energy Technology Data Exchange (ETDEWEB)
Castillo, Oswaldo Robles; Carvalho, Marcio da Silveira [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. of Mechanical Engineering
2010-07-01
The effect of the oil concentration and the drop size distribution on the characteristics of the flow of an emulsion through a constricted capillary was experimentally analyzed and quantified by the ratio of the pressure drop of the continuous phase flow to the pressure drop of the emulsion flow, at the same flow rate. The results confirm that the ratio between the capillary constriction diameter and the oil drop size is one of the most important parameters for this flow. For large oil drop size emulsions, the deformation of the drop as it flows through the constriction leads to a high extra pressure drop at low capillary numbers. For small oil drop size emulsions, the extra pressure drop is a function of the viscosity ratio and the disperse phase concentration. (author)
Energy Technology Data Exchange (ETDEWEB)
Beek, W. J.; De Ridder, H. J. [Technische Hogeschool, Delft (Netherlands); Houtman, J. P.W.; Kuiper, D. [Reactor Instituut, Delft (Netherlands)
1967-06-15
Data on residence-time distributions are important in the design of apparatus for the chemical industry. Radioactive tracers can be useful in many cases, e.g. where a pulse technique is desired. Two examples are given in which a pulse of radioactive tracer is used. The first example deals with the residence-time distribution of a laminar, Newtonian flow in an annulus. This problem arises especially in the extrusion and injection moulding of polymers and in the coating of wires with plastics. In these cases the fractions of polymer with long residence times may have other properties than the polymer that flows fastest, because the polymerization reaction or the degradation reactions go on during the process. Two difficulties are to be considered: (a) the tracer pulse (a radioactive Au-sol suspended in the liquid used) cannot be distributed over the cross-section in proportion to the local flow velocity, and (b) the outflowing liquid must be sampled discontinuously. Both effects have been studied and corrections are indicated. When these corrections are applied to the measured distribution curve, the result is in fair agreement with the calculated residence-time distribution. The second example considers the residence-time distribution in a granular solid (sand) passing through a rotary kiln. The response was measured at the outlet to a pulse at the inlet of radioactive material (sand impregnated with a solution of radioactive AuCl{sub 3}). When calculating the residence-time distribution from the experimental data, difficulties were encountered because the duration of the pulse was of the same order of magnitude as the average residence time. Considering this, it was found that the axial dispersion of the flow of sand could be described by an effective dispersion coefficient. This dispersion coefficient proved to be very low (order of magnitude 10{sup -5} m{sup 2}/s); hence, in practical situations, the flow of granular material through a rotary kiln may often be
The Single Pass RF Driver: Final beam compression
Energy Technology Data Exchange (ETDEWEB)
Burke, Robert, E-mail: rjburke@fusionpowercorporation.com
2014-01-01
The Single Pass RF Driver (SPRFD) compacts the beam from the linac without storage rings by manipulations that take advantage of the multiplicity of isotopes (16), the preserved µbunch structure, and increased total linac current. Magnetic switches on a first set of delay lines rearrange the internal structure of the various isotopic beams. A second set of delay lines sets the relative timing of the 16 isotopic beam sections so they will telescope at the pellet, in one of multiple fusion chambers, e.g. 10. Shortening each isotopic beam section uses preservation of the µbunch structure up to the final ∼2 km drift before final focus. Just before the final drift, differential acceleration of the µbunches in each isotopic beam section (128 total) launches an axial collapse, referred to as the “Slick”. The µbunches interpenetrate as their centers of mass move toward each other and individual µbunches lengthen due to their momentum spread. In longitudinal phase space they slide over one another as they lengthen in time and slim down in instantaneous energy spread. The permissible amount of µbunch lengthening is set by the design pulse shape at the pellet, which varies for different groups of isotopes. In narrow bands of ranges according to the role for each isotope group in the pellet, the ranges extend from 1 to 10 g/cm{sup 2} to drive the cylinder barrel and thin hemispherical end caps, to heat the ∼0.5 g/cm{sup 2}ρR fast ignition zone, and to improve the quasi-sphericity of the compression of the fast ignition zones at the pellet's ends. Because the µbunch–µbunch momentum differences are correlated, time-ramped beamline transport elements close after the differential accelerator are used to correct the associated shifts of focal point. Beam neutralization is needed after the differential acceleration until adjacent bunches begin to overlap. Concurrent collapse of each isotope and telescoping of the 16 isotopes cause the current in each beamline
The Single Pass RF Driver: Final beam compression
International Nuclear Information System (INIS)
Burke, Robert
2014-01-01
The Single Pass RF Driver (SPRFD) compacts the beam from the linac without storage rings by manipulations that take advantage of the multiplicity of isotopes (16), the preserved µbunch structure, and increased total linac current. Magnetic switches on a first set of delay lines rearrange the internal structure of the various isotopic beams. A second set of delay lines sets the relative timing of the 16 isotopic beam sections so they will telescope at the pellet, in one of multiple fusion chambers, e.g. 10. Shortening each isotopic beam section uses preservation of the µbunch structure up to the final ∼2 km drift before final focus. Just before the final drift, differential acceleration of the µbunches in each isotopic beam section (128 total) launches an axial collapse, referred to as the “Slick”. The µbunches interpenetrate as their centers of mass move toward each other and individual µbunches lengthen due to their momentum spread. In longitudinal phase space they slide over one another as they lengthen in time and slim down in instantaneous energy spread. The permissible amount of µbunch lengthening is set by the design pulse shape at the pellet, which varies for different groups of isotopes. In narrow bands of ranges according to the role for each isotope group in the pellet, the ranges extend from 1 to 10 g/cm 2 to drive the cylinder barrel and thin hemispherical end caps, to heat the ∼0.5 g/cm 2 ρR fast ignition zone, and to improve the quasi-sphericity of the compression of the fast ignition zones at the pellet's ends. Because the µbunch–µbunch momentum differences are correlated, time-ramped beamline transport elements close after the differential accelerator are used to correct the associated shifts of focal point. Beam neutralization is needed after the differential acceleration until adjacent bunches begin to overlap. Concurrent collapse of each isotope and telescoping of the 16 isotopes cause the current in each beamline to rise
Flow of two stratified fluids in an open channel with addition of fluids along the channel length
International Nuclear Information System (INIS)
Gardner, G.C.
1980-01-01
It is shown that two stably stratified fluids flowing in an open channel have two critical flow conditions. The one at higher flowrates is equivalent to the choked flow condition of a single fluid over a broad-crested weir, when the Froude number is unity. The lower critical condition imposes restrictions, which define the system if fluids are added progressively along the channel length and the flowrates increase from low to high values. However, if the flowrate does not become sufficiently large to pass through the lower critical condition, this condition will then define a form of choking, which again determines the system. It is shown that an important special case, with the proportional flowrates of the two fluids kept constant, has an analytical solution in which the relative depths of the fluids is a constant along the channel. Other systems must be solved numerically. (orig.)
Transient gas flow through layered porous media
International Nuclear Information System (INIS)
Morrison, F.A. Jr.
1975-01-01
Low Reynolds number isothermal flow of an ideal gas through layered porous material was investigated analytically. Relations governing the transient flow in one dimension are obtained. An implicit, iterative, unconditionally stable finite difference scheme is developed for calculation of such flows. A computer code, SIROCCO, employing this technique has been written and implemented on the LLL computer system. A listing of the code is included. This code may be effectively applied to the evaluation of stemming plans for underground nuclear experiments. (U.S.)
Feaster, Toby D.; Lee, Kathyrn G.
2017-08-28
Low-flow statistics are needed by water-resource engineers, planners, and managers to protect and manage the water resources of Alabama. The accuracy of these statistics is influenced by such factors as length of record and specific hydrologic conditions measured in those records. As such, it is generally recommended that flow statistics be updated about every 10 years to provide improved and representative low-flow characteristics. The previous investigation of low-flow characteristics for Alabama included data through September 1990. Since that time, Alabama has experienced several historic droughts highlighting the need to update the low-flow characteristics at U.S. Geological Survey streamgaging stations. Consequently, this investigation was undertaken in cooperation with a number of State and local agencies to update low-flow frequency and flow-duration statistics at 210 continuous-record streamgaging stations in Alabama and 67 stations from basins that are shared with surrounding States. The flow characteristics were computed on the basis of available data through March 2014.
TR-PIV Performance Test for a Flow Field Measurement in a Single Rod Test Section
International Nuclear Information System (INIS)
Park, Ju Yong; Shin, Chang Hwan; Lee, Chi Young; Oh, Dong Seok; In, Wang Kee
2011-01-01
For large enhancement of performance of Pressurized Water Reactor(PWR), dual-cooled fuel is being developed in Korea Atomic Energy Research Institute(KAERI). This nuclear fuel is a ring shape fuel which is different from conventional cylindrical nuclear fuel and cooling water flows both inner and outer channel. For this fuel, it widens the surface area. But it is bigger outer diameter of fuel rods. So, interval between fuel rods narrows. This because of outer channel flow is unstable. So, measurement of turbulence flow and perturbation that influence in heat transfer elevation is important.. To understand heat transfer characteristics by turbulence, measurement of flow perturbation element is necessary. To measure these turbulence characteristics, hot wire anemometer is widely used. However, it has many disadvantages such as low durability of prove, and big probe size. For these reasons, TR-PIV(Time-Resolved Particle Image Velocimetry) system is employed for better flow measurement in our research institute. TR-PIV system is consisted of laser system and high-speed camera that have high frequency. So, was judged that can measurement complicated turbulence flow and perturbation. In this paper, introduce TR-PIV system, and with results acquiring in single rod flow through this system, and wish to introduce about after this practical use plan
Buoyancy flow in fractures intersecting a nuclear waste repository
International Nuclear Information System (INIS)
Wang, J.S.Y.; Tsang, C.F.
1980-07-01
The thermally induced buoyancy flow in fractured rocks around a nuclear waste repository is of major concern in the evaluation of the regional, long-term impact of nuclear waste disposal in geological formation. In this study, buoyancy flow and the development of convective cells are calculated in vertical fractures passing through or positioned near a repository. Interaction between buoyancy flow and regional hydraulic gradient is studied as a function of time, and the interference of intersecting fractures with each other is also discussed
International Nuclear Information System (INIS)
Hamel, W.R.
1984-01-01
This invention relates to a new method and new apparatus for determining fluid mass flow rate and density. In one aspect of the invention, the fluid is passed through a straight cantilevered tube in which transient oscillation has been induced, thus generating Coriolis damping forces on the tube. The decay rate and frequency of the resulting damped oscillation are measured, and the fluid mass flow rate and density are determined therefrom. In another aspect of the invention, the fluid is passed through the cantilevered tube while an electrically powered device imparts steady-state harmonic excitation to the tube. This generates Coriolis tube-damping forces which are dependent on the mass flow rate of the fluid. Means are provided to respond to incipient flow-induced changes in the amplitude of vibration by changing the power input to the excitation device as required to sustain the original amplitude of vibration. The fluid mass flow rate and density are determined from the required change in power input. The invention provides stable, rapid, and accurate measurements. It does not require bending of the fluid flow
International Nuclear Information System (INIS)
Sijm, J.; Chen, Y.; Hobbs, B.F.
2012-01-01
We present a theoretical analysis of the impact of power market structure on the pass-through rate (PTR) of CO2 emissions trading (ET) costs on electricity prices. Market structure refers in particular to the number of firms active in the market and the intensity of oligopolistic competition as measured by the conjectural variation, as well as to the functional form of the power demand and supply curves. In addition, we analyse briefly the impact of other power market-related factors on the PTR of carbon costs to electricity prices. These include in particular the impact of ET-induced changes in the merit order of power generation technologies and the impact of pursuing other market strategies besides maximising generator profit, such as maximising market shares or sales revenues of power companies. Each of these factors can have a significant impact on the rate of passing-through carbon costs to electricity prices.
Flow sorting in the study of teratocarcinoma cell differentiation
G.H. Schaap (Gerard Hendrik)
1984-01-01
textabstractFlow cytometry is a technique by which particles (cells, subcellular fragments, bacteria) in aqueous suspension are passed one by one through a sensing region where optical (or electrical) signals are generated. These signals for each individual cell are collected and processed, and may
Low-pass sequencing for microbial comparative genomics
Directory of Open Access Journals (Sweden)
Kennedy Sean
2004-01-01
Full Text Available Abstract Background We studied four extremely halophilic archaea by low-pass shotgun sequencing: (1 the metabolically versatile Haloarcula marismortui; (2 the non-pigmented Natrialba asiatica; (3 the psychrophile Halorubrum lacusprofundi and (4 the Dead Sea isolate Halobaculum gomorrense. Approximately one thousand single pass genomic sequences per genome were obtained. The data were analyzed by comparative genomic analyses using the completed Halobacterium sp. NRC-1 genome as a reference. Low-pass shotgun sequencing is a simple, inexpensive, and rapid approach that can readily be performed on any cultured microbe. Results As expected, the four archaeal halophiles analyzed exhibit both bacterial and eukaryotic characteristics as well as uniquely archaeal traits. All five halophiles exhibit greater than sixty percent GC content and low isoelectric points (pI for their predicted proteins. Multiple insertion sequence (IS elements, often involved in genome rearrangements, were identified in H. lacusprofundi and H. marismortui. The core biological functions that govern cellular and genetic mechanisms of H. sp. NRC-1 appear to be conserved in these four other halophiles. Multiple TATA box binding protein (TBP and transcription factor IIB (TFB homologs were identified from most of the four shotgunned halophiles. The reconstructed molecular tree of all five halophiles shows a large divergence between these species, but with the closest relationship being between H. sp. NRC-1 and H. lacusprofundi. Conclusion Despite the diverse habitats of these species, all five halophiles share (1 high GC content and (2 low protein isoelectric points, which are characteristics associated with environmental exposure to UV radiation and hypersalinity, respectively. Identification of multiple IS elements in the genome of H. lacusprofundi and H. marismortui suggest that genome structure and dynamic genome reorganization might be similar to that previously observed in the
Fiber optic liquid mass flow sensor and method
Korman, Valentin (Inventor); Gregory, Don Allen (Inventor); Wiley, John T. (Inventor); Pedersen, Kevin W. (Inventor)
2010-01-01
A method and apparatus are provided for sensing the mass flow rate of a fluid flowing through a pipe. A light beam containing plural individual wavelengths is projected from one side of the pipe across the width of the pipe so as to pass through the fluid under test. Fiber optic couplers located at least two positions on the opposite side of the pipe are used to detect the light beam. A determination is then made of the relative strengths of the light beam for each wavelength at the at least two positions and based at least in part on these relative strengths, the mass flow rate of the fluid is determined.
High Viscosity Liquid Flow through the Round Orifices at Small Reynold’s Numbe rs
Directory of Open Access Journals (Sweden)
V. N. Pil'gunov
2015-01-01
Full Text Available The paper presents research results of the mineral oil flow process with viscosity of 30 cSt through a round orifice with the sharp inlet edge of 0.9 mm in diameter. Pilot studies were conducted using a module from the transparent plexiglas that allowed to visualize hydrodynamic processes. The intake and off-take channels of the module with their sufficient extension had diameter of 20 mm (24 diameters of an orifice that allows us to consider compression of a stream as perfect. Drawing the enameled nichrome wire with a mark as a stripping isolation of 0.1 mm width enabled sounding of electric processes in the stream sections. Intensive high- frequency electric processes were revealed in cavitation stream. The paper gives experimental values of coefficientsof volumetric and mass flow at low (150
Beyond Illinois Brick: The Law and Economics of Cost Pass-Through in the ADM Price Fixing Case
Ronald W. Cotterill; Leonard Egan; William Buckhold
1998-01-01
This article reviews the legal standards and the economics of indirect purchaser cases. Drawn from recent cases on behalf of consumers in the ADM price fixing case, it presents cost pass through models for high fructose corn syrup (HFCS), one of the alleged price fixes in the wet corn milling industry. If soft drink bottlers, a primary user of HFCS, have fixed proportion production, constant returns to scale, and if other bottlers input prices are unaffected by variations in soft drink output...
Introduction: Mirrors of Passing
DEFF Research Database (Denmark)
Seebach, Sophie Hooge; Willerslev, Rane
How is death, time, and materiality interconnected? How to approach an understanding of the world of the dead? In this introduction, we seek to understand how the experience of material decay, of the death of those around us, makes us aware of the passing of time. Through the literary lens of Neil...... Gaiman’s The Graveyard Book, we explore how the world of the dead and the world of the living can intersect; how time and materiality shifts and changes depending on who experiences it. These revelations, based on fiction, provide a mirror through which the reader can experience the varied chapters...
Dipolar flow theory of the universe in relation to astronomical observations and universe axis
International Nuclear Information System (INIS)
Mullick, U.P.
1975-01-01
An attempt has been made to establish Dipolar continuous flow theory of the universe through corroborations from astronomical observations of the positions of nebulae made earlier by astronomers. It is shown that the line through groups of nebulae in Nubecula Major in Southern Sky Region 5, passing through Earth points towards the near side pole A of the universe. Also the angles the plane parallel to universe polar plane x-x and passing through Earth, makes with the Milky Way disc is about 70 0 towards universe pole B, and about 110 0 towards nearside universe pole A. It is also shown that the two nebulae M 31 and M 33 and the groups of nebulae in Megallenic clouds, in Nebecula Major are between planes passing through universe equatorial axis y-y and plant Ysub(E)-Ysub(E) passing through Earth and parallel to universe equatorial plane Y-Y. Besides, the huge red star Betelgeux and the great Nebula in Orion in sky Region 9 are also between these two planes. These observations the author claims accord with his Dipolar Theory. (author)
Theoretical Investigations Regarding Single Molecules
DEFF Research Database (Denmark)
Pedersen, Kim Georg Lind
Neoclassical Valence Bond Theory, Quantum Transport, Quantum Interference, Kondo Effect, and Electron Pumping. Trap a single organic molecule between two electrodes and apply a bias voltage across this "molecular junction". When electrons pass through the molecule, the different electron paths can...... interfere destructively or constructively. Destructive interference effects in electron transport could potentially improve thermo-electrics, organic logic circuits and energy harvesting. We have investigated destructive interference in off-resonant transport through organic molecules, and have found a set...
Propagation of atmospheric pressure helium plasma jet into ambient air at laminar gas flow
International Nuclear Information System (INIS)
Pinchuk, M; Kurakina, N; Spodobin, V; Stepanova, O
2017-01-01
The formation of an atmospheric pressure plasma jet (APPJ) in a gas flow passing through the discharge gap depends on both gas-dynamic properties and electrophysical parameters of the plasma jet generator. The paper presents the results of experimental and numerical study of the propagation of the APPJ in a laminar flow of helium. A dielectric-barrier discharge (DBD) generated inside a quartz tube equipped with a coaxial electrode system, which provided gas passing through it, served as a plasma source. The transition of the laminar regime of gas flow into turbulent one was controlled by the photography of a formed plasma jet. The corresponding gas outlet velocity and Reynolds numbers were revealed experimentally and were used to simulate gas dynamics with OpenFOAM software. The data of the numerical simulation suggest that the length of plasma jet at the unvarying electrophysical parameters of DBD strongly depends on the mole fraction of ambient air in a helium flow, which is established along the direction of gas flow. (paper)
International Nuclear Information System (INIS)
Munmuangsaen, Buncha; Srisuchinwong, Banlue
2011-01-01
Highlights: → Five new elementary chaotic snap flows and a generalization of an existing chaotic snap flow have been presented. → Three of all are conservative systems whilst three others are dissipative systems. → Four cases need only a single control parameter and a single nonlinearity. → A cubic case in a jerk representation requires only two terms and a single nonlinearity. - Abstract: Hyperjerk systems with 4th-order derivative of the form x .... =f(x ... ,x .. ,x . ,x) have been referred to as snap systems. Five new elementary chaotic snap flows and a generalization of an existing flow are presented through an extensive numerical search. Four of these flows demonstrate elegant simplicity of a single control parameter based on a single nonlinearity of a quadratic, a piecewise-linear or an exponential type. Two others demonstrate elegant simplicity of all unity-in-magnitude parameters based on either a single cubic nonlinearity or three cubic nonlinearities. The chaotic snap flow with a single cubic nonlinearity requires only two terms and can be transformed to its equivalent dynamical form of only five terms which have a single nonlinearity. An advantage is that such a chaotic flow offers only five terms even though the (four) dimension is high. Three of the chaotic snap flows are characterized as conservative systems whilst three others are dissipative systems. Basic dynamical properties are described.
DYNAM, Once Through Boiling Flow with Steam Superheat, Laplace Transformation
International Nuclear Information System (INIS)
Schlueter, G.; Efferding, L.E.
1973-01-01
1 - Description of problem or function: DYNAM performs a dynamic analysis of once-through boiling flow oscillations with steam superheat. The model describing the superheat regime (single- phase, variable density fluid) for subcritical pressure operation is also applicable to the study of once-through operation using supercritical pressure water. 2 - Method of solution: Linearized partial differential conservation equations are solved using Laplace transformation of the temporal terms and integration of the spatial variations. DYNAM is written in complex variable notation. 3 - Restrictions on the complexity of the problem - Maxima of: 30 intervals used to describe the power distribution in the non-boiling and boiling regions, 29 boiling nodes, 7 intervals and corresponding friction multipliers read in per case, 14 exit qualities read in per case, 40 superheat nodes, 10 coefficients read in for the phi 2 vs, x-polynomial fit, 48 frequencies at which open-loop frequency response is desired, 48 frequencies at which signal output is desired
Double-Sided Single-Pass Submerged Arc Welding for 2205 Duplex Stainless Steel
Luo, Jian; Yuan, Yi; Wang, Xiaoming; Yao, Zongxiang
2013-09-01
The duplex stainless steel (DSS), which combines the characteristics of ferritic steel and austenitic steel, is used widely. The submerged arc welding (SAW) method is usually applied to join thick plates of DSS. However, an effective welding procedure is needed in order to obtain ideal DSS welds with an appropriate proportion of ferrite (δ) and austenite (γ) in the weld zone, particularly in the melted zone and heat-affected zone. This study evaluated the effectiveness of a high efficiency double-sided single-pass (DSSP) SAW joining method for thick DSS plates. The effectiveness of the converse welding procedure, characterizations of weld zone, and mechanical properties of welded joint are analyzed. The results show an increasing appearance and continuous distribution feature of the σ phase in the fusion zone of the leading welded seam. The converse welding procedure promotes the σ phase to precipitate in the fusion zone of leading welded side. The microhardness appears to significantly increase in the center of leading welded side. Ductile fracture mode is observed in the weld zone. A mixture fracture feature appears with a shear lip and tears in the fusion zone near the fusion line. The ductility, plasticity, and microhardness of the joints have a significant relationship with σ phase and heat treatment effect influenced by the converse welding step. An available heat input controlling technology of the DSSP formation method is discussed for SAW of thick DSS plates.
Energy Technology Data Exchange (ETDEWEB)
Neretnieks, Ivars [Dept. of Chemical Engineering and Technology, Royal Institute of Technology, Stockholm (Sweden)
2006-12-15
The compacted bentonite buffer that surrounds the canister with spent fuel is designed not to allow water to flow through it in any appreciable quantities. Should the buffer be severely damaged water could flow to the canister and bring with it corrosive agent such as sulphide. This could speed up the rate of copper corrosion. Should the canister have a damage or be corroded so that the spent fuel inside the canister comes in contact with the water radionuclides could dissolve in the water and be carried away. Two modes of canister damage and their consequences for solute transport are explored in this report. In one case the buffer can potentially be eroded by the water seeping in the fractures in the surrounding rock and attain a high hydraulic conductivity allowing water to flow through it, at least locally. In another case it is conjectured that the buffer is cemented and becomes brittle. Then a crack could conceivably form in the cemented buffer allowing water to flow through it directly to the canister surface. Both cases are hypothetical although in the erosion case the erosion rate could possibly be quantified. The cases studied are to be seen as exploratory calculations for 'what if' cases. Some worst case assumptions have been used to explore bounding scenarios. Thus for the erosion case it is assumed that the hydraulic conductivity is so high that the buffer exerts negligible resistance to water flow. This implies that all the water that can flow through the fractures intersecting the deposition hole can reach the canister. Similarly for the cemented buffer case it is assumed that the crack in the buffer directly connects the rock fracture to the canister surface. For these circumstances it is found that the flowrate that can enter the deposition hole will be approximately two times as large as the water flow that would pass a projected area equal to that of the deposition hole. Thus if the flux in the rock some distance from the deposition
International Nuclear Information System (INIS)
Neretnieks, Ivars
2006-12-01
The compacted bentonite buffer that surrounds the canister with spent fuel is designed not to allow water to flow through it in any appreciable quantities. Should the buffer be severely damaged water could flow to the canister and bring with it corrosive agent such as sulphide. This could speed up the rate of copper corrosion. Should the canister have a damage or be corroded so that the spent fuel inside the canister comes in contact with the water radionuclides could dissolve in the water and be carried away. Two modes of canister damage and their consequences for solute transport are explored in this report. In one case the buffer can potentially be eroded by the water seeping in the fractures in the surrounding rock and attain a high hydraulic conductivity allowing water to flow through it, at least locally. In another case it is conjectured that the buffer is cemented and becomes brittle. Then a crack could conceivably form in the cemented buffer allowing water to flow through it directly to the canister surface. Both cases are hypothetical although in the erosion case the erosion rate could possibly be quantified. The cases studied are to be seen as exploratory calculations for 'what if' cases. Some worst case assumptions have been used to explore bounding scenarios. Thus for the erosion case it is assumed that the hydraulic conductivity is so high that the buffer exerts negligible resistance to water flow. This implies that all the water that can flow through the fractures intersecting the deposition hole can reach the canister. Similarly for the cemented buffer case it is assumed that the crack in the buffer directly connects the rock fracture to the canister surface. For these circumstances it is found that the flowrate that can enter the deposition hole will be approximately two times as large as the water flow that would pass a projected area equal to that of the deposition hole. Thus if the flux in the rock some distance from the deposition hole is 1
Brook trout passage performance through culverts
Goerig, Elsa; Castro-Santos, Theodore R.; Bergeron, Normand
2016-01-01
Culverts can restrict access to habitat for stream-dwelling fishes. We used passive integrated transponder telemetry to quantify passage performance of >1000 wild brook trout (Salvelinus fontinalis) attempting to pass 13 culverts in Quebec under a range of hydraulic and environmental conditions. Several variables influenced passage success, including complex interactions between physiology and behavior, hydraulics, and structural characteristics. The probability of successful passage was greater through corrugated metal culverts than through smooth ones, particularly among smaller fish. Trout were also more likely to pass at warmer temperatures, but this effect diminished above 15 °C. Passage was impeded at higher flows, through culverts with steep slopes, and those with deep downstream pools. This study provides insight on factors influencing brook trout capacity to pass culverts as well as a model to estimate passage success under various conditions, with an improved resolution and accuracy over existing approaches. It also presents methods that could be used to investigate passage success of other species, with implications for connectivity of the riverscape.
Upaya Meningkatkan Kemampuan Passing Bawah Bola Voli Pada
Irawan, Dedi
2017-01-01
This research uses research "Classroom Action Research" (Classroom Action Research) with variables: Improved Passing Down volleyball through media modified rubber ball. Subjects in this study were fifth grade students of State Elementary School 23 Palus Hulu subdistrict Belimbing Melawi totaling 28 students. This research technique using test and measurement, a test with a grating instrument measuring learning outcomes passing down the volleyball game. Analysis of data using percentages. Thes...
Experimental Study of Cavitation in Laminar Flow
Croci , Kilian; Ravelet , Florent; ROBINET , Jean-Christophe; Danlos , Amélie
2017-01-01
An experimental setup has been especially developed in order to observe cavitation in laminar flows. Experiments have been carried out with a silicon oil of viscosity υ = 100cSt passing through a Venturi-type geometry with 18°/8° convergent/divergent angles respectively. The range of Reynolds numbers at the inlet section is between 350 and 1000. Two dynamic regimes are identified. They are characterized by two critical Reynolds numbers, induced by major hydrodynamic changes in the flow, in ad...
International Nuclear Information System (INIS)
Takahashi, Minoru; Momozaki, Yoichi
2000-01-01
For the reduction of a large magneto-hydrodynamic (MHD) pressure drop of a liquid metal single-phase flow, a liquid metal two-phase flow cooling system has been proposed. As a fundamental study, MHD pressure drops and heat transfer characteristics of a mercury single-phase flow and an air-mercury two-phase flow were experimentally investigated. A strong transverse magnetic field relevant to the fusion reactor conditions was applied to the mercury single-phase flow and the air-mercury two-phase flow in a helically coiled tube that was inserted in the vertical bore of a solenoidal superconducting magnet. It was found that MHD pressure drops of a mercury single-phase flow in the helically coiled tube were nearly equal to those in a straight tube. The Nusselt number at an outside wall was higher than that at an inside wall both in the mercury single-phase flow in the absence and presence of a magnetic field. The Nusselt number of the mercury single-phase flow decreased, increased and again decreased with an increase in the magnetic flux density. MHD pressure drops did not decrease appreciably by injecting air into a mercury flow and changing the mercury flow into the air-mercury two-phase flow. Remarkable heat transfer enhancement did not appear by the air injection. The injection of air into the mercury flow enhanced heat transfer in the ranges of high mercury flow rate and low magnetic flux density, possibly due to the agitation effect of air bubbles. The air injection deteriorated heat transfer in the range of low mercury flow rates possibly because of the occupation of air near heating wall
2D model for melt progression through rods and debris
International Nuclear Information System (INIS)
Fichot, F.
2001-01-01
During the degradation of a nuclear core in a severe accident scenario, the high temperatures reached lead to the melting of materials. The formation of liquid mixtures at various elevations is followed by the flow of molten materials through the core. Liquid mixture may flow under several configurations: axial relocation along the rods, horizontal motion over a plane surface such as the core support plate or a blockage of material, 2D relocation through a debris bed, etc.. The two-dimensional relocation of molten material through a porous debris bed, implemented for the simulation of late degradation phases, has opened a new way to the elaboration of the relocation model for the flow of liquid mixture along the rods. It is based on a volume averaging method, where wall friction and capillary effects are taken into account by introducing effective coefficients to characterize the solid matrix (rods, grids, debris, etc.). A local description of the liquid flow is necessary to derive the effective coefficients. Heat transfers are modelled in a similar way. The derivation of the conservation equations for the liquid mixture falling flow (momentum) in two directions (axial and radial-horizontal) and for the heat exchanges (energy) are the main points of this new model for simulating melt progression. In this presentation, the full model for the relocation and solidification of liquid materials through a rod bundle or a debris bed is described. It is implemented in the ICARE/CATHARE code, developed by IPSN in Cadarache. The main improvements and advantages of the new model are: A single formulation for liquid mixture relocation, in 2D, either through a rod bundle or a porous debris bed, Extensions to complex structures (grids, by-pass, etc..), The modeling of relocation of a liquid mixture over plane surfaces. (author)
Organic compounds generated after the flow of water through micro-orifices: Were they synthesized?
Directory of Open Access Journals (Sweden)
Tomiichi Hasegawa
2017-08-01
Full Text Available Micro-fluid mechanics is an important area of research in modern fluid mechanics because of its many potential industrial and biological applications. However, the field is not fully understood yet. In previous work, when passing ultrapure water (UPW in which air was dissolved (UPW* through micro-orifices, we found that the flow velocity decreased and stopped over time, and membranes were frequently formed in the orifice when the flow stopped. The membrane came from the dissolved air in UPW*, and membrane formation was closely related to electric charges generated in orifices by the flow. In the present paper, we clarified the components of the membrane and suggested a mechanism for membrane formation. We examined the effect of contaminants on the membrane formation and confirmed our previous results. We identified the chemical components of the membrane and those present in the UPW* itself by using an electron probe microanalyzer and found that the proportion of each element differed between the membrane and UPW*. Raman and infrared (IR spectroscopy showed that the membrane consisted of organic substances such as carotenoids, amides, esters, and sugars. We irradiated UPW* with ultraviolet light to cut organic chains that may be left in UPW* as contaminants. We found a similar membrane and organic compounds as in nonirradiated UPW*. Furthermore, although the UPW that was kept from contact with air after it was supplied from the UPW maker (UPW0 and bubbled with Ar gas (UPW0 bubbled with Ar formed no membrane, the UPW0 bubbled with CO2 formed thin membranes, and Raman and IR analysis showed that this membrane contained carboxylic acid salts, carotenoids, or a mixture of both. We found that electric grounding of the orifice reduces the probability of membrane formation and that the jets issuing from an aperture bear negative charges, and we assumed that the micro-orifices possess positive charges generated by flows. Consequently, we suggest that
Effectiveness-ntu computation with a mathematical model for cross-flow heat exchangers
Directory of Open Access Journals (Sweden)
H. A. Navarro
2007-12-01
Full Text Available Due to the wide range of design possibilities, simple manufactured, low maintenance and low cost, cross-flow heat exchangers are extensively used in the petroleum, petrochemical, air conditioning, food storage, and others industries. In this paper a mathematical model for cross-flow heat exchangers with complex flow arrangements for determining epsilon -NTU relations is presented. The model is based on the tube element approach, according to which the heat exchanger outlet temperatures are obtained by discretizing the coil along the tube fluid path. In each cross section of the element, tube-side fluid temperature is assumed to be constant because the heat capacity rate ratio C*=Cmin/Cmax tends toward zero in the element. Thus temperature is controlled by effectiveness of a local element corresponding to an evaporator or a condenser-type element. The model is validated through comparison with theoretical algebraic relations for single-pass cross-flow arrangements with one or more rows. Very small relative errors are obtained showing the accuracy of the present model. epsilon -NTU curves for several complex circuit arrangements are presented. The model developed represents a useful research tool for theoretical and experimental studies on heat exchangers performance.
Effect of pass schedule and groove design on the metal deformation ...
Indian Academy of Sciences (India)
c Indian Academy of Sciences. Effect of pass schedule and ... metal flow behaviour in a hot rolling process is a complex phenomenon, which is ... Computer based FEM simulations incorporating deformation mod- els can be used to develop ...
Buck Creek River Flow Analysis
Dhanapala, Yasas; George, Elizabeth; Ritter, John
2009-04-01
Buck Creek flowing through Springfield Ohio has a number of low-head dams currently in place that cause safety issues and sometimes make it impossible for recreational boaters to pass through. The safety issues include the back eddies created by the dams that are known as drowning machines and the hydraulic jumps. In this study we are modeling the flow of Buck Creek using topographical and flow data provided by the Geology Department of Wittenberg University. The flow is analyzed using Hydraulic Engineering Center - River Analysis System software (HEC-RAS). As the first step a model of the river near Snyder Park has been created with the current structure in place for validation purposes. Afterwards the low-head dam is replaced with four drop structures with V-notch overflow gates. The river bed is altered to reflect plunge pools after each drop structure. This analysis will provide insight to how the flow is going to behave after the changes are made. In addition a sediment transport analysis is also being conducted to provide information about the stability of these structures.
3D characterization of a Great Basin geothermal system: Astor Pass, NV
Siler, D. L.; Mayhew, B.; Faulds, J. E.
2012-12-01
The Great Basin exhibits both anomalously high heat flow (~75±5 mWm-2) and active faulting and extension resulting in robust geothermal activity. There are ~430 known geothermal systems in the Great Basin, with evidence suggesting that undiscovered blind geothermal systems may actually represent the majority of geothermal activity. These systems employ discrete fault intersection/interaction areas as conduits for geothermal circulation. Recent studies show that steeply dipping normal faults with step-overs, fault intersections, accommodation zones, horse-tailing fault terminations and transtensional pull-aparts are the most prominent structural controls of Great Basin geothermal systems. These fault geometries produce sub-vertical zones of high fault and fracture density that act as fluid flow conduits. Structurally controlled fluid flow conduits are further enhanced when critically stressed with respect to the ambient stress conditions. The Astor Pass blind geothermal system, northwestern Nevada, lies along the boundary between the Basin and Range to the east and the Walker Lane to the west. Along this boundary, strain is transferred from dextral shear in the Walker Lane to west-northwest directed extension in the Basin and Range. As such, the Astor Pass area lies in a transtensional setting consisting of both northwest-striking, left-stepping dextral faults and more northerly striking normal faults. The Astor Pass tufa tower implies the presence of a blind geothermal system. Previous studies suggest that deposition of the Astor Pass tufa was controlled by the intersection of a northwest-striking dextral normal fault and north-northwest striking normal fault. Subsequent drilling (to ~1200 m) has revealed fluid temperatures of ~94°C, confirming the presence of a blind geothermal system at Astor Pass. Expanding upon previous work and employing additional detailed geologic mapping, interpretation of 2D seismic reflection data and analysis of well cuttings, a 3
Charge-equilibrium and radiation of low-energy cosmic rays passing through interstellar medium
Rule, D. W.; Omidvar, K.
1977-01-01
The charge equilibrium and radiation of an oxygen and an iron beam in the MeV per nucleon energy range, representing a typical beam of low-energy cosmic rays passing through the interstellar medium, is considered. Electron loss of the beam has been taken into account by means of the First Born approximation allowing for the target atom to remain unexcited, or to be excited to all possible states. Electron capture cross sections have been calculated by means of the scaled Oppenheimer-Brinkman-Kramers approximation, taking into account all atomic shells of the target atoms. Radiation of the beam due to electron capture into the excited states of the ion, collisional excitation and collisional inner-shell ionization of the ions has been considered. Effective X-ray production cross sections and multiplicities for the most energetic X-ray lines emitted by the Fe and O beams have been calculated.
Investor Behavior and Flow-Through Capability in the US Stock Market
Directory of Open Access Journals (Sweden)
Carlos eCano
2016-05-01
Full Text Available This paper analyzes investor behavior depending on the flow-through capability in the US stock market, because investors seek protection from inflation rate changes, and the flow-through capability (a firm’s ability to transmit inflation shocks to the prices of its products and services is a key factor in investment decisions. Our estimates of the flow-through capability of firms listed on the US stock exchange at the sector level are significantly different among industries, and we demonstrate a direct relationship between changes in stock prices (at the sector level and flow-through capability. These results would be relevant because they have important implications on investor behavior.
International Nuclear Information System (INIS)
Bennett, D.L.; Schwarz, A.; Thorogood, R.M.
1987-01-01
This patent describes a process for boiling flowing liquids in a heat exchanger wherein the flowing liquids is heated in a single heat exchanger to vaporize the liquid. The improvement described here comprises: (a) passing the boiling flowing liquid through a first heat transfer zone of the heat exchanger comprising a surface with a high-convective-heat-transfer characteristic and a higher pressure drop characteristic; and then (b) passing the boiling flowing liquid through a second heat transfer zone of the heat exchanger comprising an essentially open channel with only minor obstructions by secondary surfaces, with an enhanced nucleate boiling heat transfer surface and a lower pressure drop characteristic
A numerical investigation on the unstable flow in a single stage of an axial compressors
Farhanieh, B; Ghorbanian, K
2003-01-01
An unsteady two-dimensional finite-volume solver was developed based on Van Leer's flux splitting algorithm in conjunction with sup M onotonic Upstream Scheme for Conservation Laws sup l imiters to improve the order of accuracy and the two-layer Baldwin-Lomax turbulence model was also implemented. Two test cases were prepared to validate the solver. The computed results were compared with the experimental data and a good agreement validated the solver. Finally, the solver was used for the flow through a multi-blade stage of an axial compressor in its off-design condition. The computed results showed a rotating stall-like instability with a periodic behavior. To investigate the flow properties during the instability condition, the flow pattern, vortex properties and the axial velocity were studied. It was concluded that the instability vortices in the multi-blade cascade do not have the same generation history of the separated vortices over a single body.
Do cold, low salinity waters pass through the Indo-Sri Lanka Channel during winter?
Digital Repository Service at National Institute of Oceanography (India)
Rao, R.R.; Girishkumar, M.S.; Ravichandran, M.; Gopalakrishna, V.V.; Pankajakshan, T.
cooler, low-salinity waters from the head Bay of Bengal (BoB) into the south-eastern AS. But due to a lack of any direct in situ measurements, it is not clear whether any part of this current that flows through the Indo-Sri Lanka Channel (ISLC...
Controlled generation and use of CO in flow
DEFF Research Database (Denmark)
Hansen, Steffen V. F.; Wilson, Zoe E.; Ulven, Trond
2016-01-01
A method for the generation and use of carbon monoxide in flow chemistry has been developed. By using a tube-in-tube reactor, oxalyl chloride can be conveniently and safely hydrolyzed using a NaOH solution to generate CO in the outer stream, which then passes through AF-2400 semi-permeable inner...
Pressure Drop Correlations of Single-Phase and Two-Phase Flow in Rolling Tubes
International Nuclear Information System (INIS)
Xia-xin Cao; Chang-qi Yan; Pu-zhen Gao; Zhong-ning Sun
2006-01-01
A series of experimental studies of frictional pressure drop for single phase and two-phase bubble flow in smooth rolling tubes were carried out. The tube inside diameters were 15 mm, 25 mm and 34.5 mm respectively, the rolling angles of tubes could be set as 10 deg. and 20 deg., and the rolling periods could be set as 5 s, 10 s and 15 s. Combining with the analysis of single-phase water motion, it was found that the traditional correlations for calculating single-phase frictional coefficient were not suitable for the rolling condition. Based on the experimental data, a new correlation for calculating single-phase frictional coefficient under rolling condition was presented, and the calculations not only agreed well with the experimental data, but also could display the periodically dynamic characteristics of frictional coefficients. Applying the new correlation to homogeneous flow model, two-phase frictional pressure drop of bubble flow in rolling tubes could be calculated, the results showed that the relative error between calculation and experimental data was less than ± 25%. (authors)
IN-VITRO EVALUATION OF BLOOD-FLOW THROUGH AUTOPERFUSION BALLOON CATHETERS
DEMUINCK, ED; ANGELINI, P; DOUGHERTY, K; VERKERKE, BJ; RAKHORST, G; VANDIJK, RB; LIE, KI
The effective flow rates with human blood through an autoperfusion catheter cannot be monitored in vivo and have not been experimentally determined in vitro. The manufacturers (Advanced Cardiovascular Systems [ACS], Temecula, CA) have suggested that ''the flow rate'' through the Stack(TM) over the
International Nuclear Information System (INIS)
Sijm, J.; Chen, Yihsu; Hobbs, B.F.
2009-06-01
This paper analyses the impact of power market structure on the pass-through rate (PTR) of CO2 emissions trading costs on electricity prices from a theoretical point of view, including graphical illustrations and mathematical proofs. Market structure refers in particular to the number of firms active in the market as well as to the shape of the power demand and supply curves. In addition, it analyses the impact of other power market related factors on the PTR of carbon costs to electricity prices, notably the impact of ET-induced changes in the merit order of power generation technologies or the impact of pursuing other market strategies besides maximising generators' profits, such as maximising market shares or sales revenues of power companies. It shows that each of these factors can have a significant impact on the rate of passing-through carbon costs to electricity prices
Energy Technology Data Exchange (ETDEWEB)
Sijm, J. [ECN Policy Studies, Petten (Netherlands); Chen, Yihsu [Merced School of Engineering, University of California, Merced, CA (United States); Hobbs, B.F. [Department of Geography and Environmental Engineering, Johns Hopkins University, Baltimore, Maryland (United States)
2009-06-15
This paper analyses the impact of power market structure on the pass-through rate (PTR) of CO2 emissions trading costs on electricity prices from a theoretical point of view, including graphical illustrations and mathematical proofs. Market structure refers in particular to the number of firms active in the market as well as to the shape of the power demand and supply curves. In addition, it analyses the impact of other power market related factors on the PTR of carbon costs to electricity prices, notably the impact of ET-induced changes in the merit order of power generation technologies or the impact of pursuing other market strategies besides maximising generators' profits, such as maximising market shares or sales revenues of power companies. It shows that each of these factors can have a significant impact on the rate of passing-through carbon costs to electricity prices.
International Nuclear Information System (INIS)
Ding Yinfeng; Zhang Zhibin; Ke Xuezhi; Zhu Zhiyuan; Zhu Dezhang; Wang Zhenxia; Xu Hongjie
2005-01-01
The single carbon atom transporting through the single-walled carbon nanotube has been studied by molecular-dynamics (MD) simulation. We got different trajectories of the carbon atom by changing the input parameters. The simulation results indicate that the single carbon atom with low energy can transport through the carbon nanotube under some input conditions and result in different trajectories being straight line or 'rosette' or circular. (authors)
International Nuclear Information System (INIS)
Kipper, S.L.; Ashburn, W.L.; Norris, S.L.; Rimkus, D.S.; Dillon, W.A.
1985-01-01
Graded, sequential, rest/exercise, gold-195m, first-pass ventriculography and thallium-201 (Tl-201) single-photon emission computed tomography (SPECT) were performed simultaneously during a single, electrocardiograph-monitored, bicycle stress test in 24 individuals. The technical aspects and logistics involved in performing this combined radionuclide study are stressed in this preliminary report. Fourteen healthy volunteers each had a normal left ventricular ejection fraction and wall-motion response, along with normal T1-201 perfusion and washout, as determined by both visual and quantitative analysis of the tomographic sections. Each of ten patients with coronary artery disease had at least one abnormality of these parameters. The authors suggest that it is technically feasible to evaluate both cardiac function and myocardial perfusion simultaneously by combing Au-195m ventriculography and Tl-201 SPECT imaging into a single, noninvasive, diagnostic package
Koval, L. R.
1975-01-01
In the context of sound transmission through aircraft fuselage panels, equations for the field-incidence transmission loss (TL) of a single-walled panel are derived that include the effects of external air flow, panel curvature, and internal fuselage pressurization. These effects are incorporated into the classical equations for the TL of single panels, and the resulting double integral for field-incidence TL is numerically evaluated for a specific set of parameters.
Donaldsson, Snorri; Falk, Markus; Jonsson, Baldvin; Drevhammar, Thomas
2015-01-01
The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.
Plastic Flow Induced by Single Ion Impacts on Gold
International Nuclear Information System (INIS)
Birtcher, R.C.; Donnelly, S.E.
1996-01-01
The formation of holes in thin gold foils as a result of single ion impacts by 200keV Xe ions has been followed using transmission electron microscopy. Video recording provided details of microstructure evolution with a time resolution of 1/30th sec. Hole formation involves the movement by plastic flow of massive amounts of material, on the order of tens of thousands of Au atoms per ion impact. Plastic flow, as a consequence of individual ion impacts, results in a continual filling of both holes and craters as well as a thickening of the gold foil. Changes in morphology during irradiation is attributed to a localized, thermal-spike induced melting, coupled with plastic flow of effected material under the influence of surface forces. copyright 1996 The American Physical Society
Hopf, H-B; Hochscherf, M; Jehmlich, M; Leischik, M; Ritter, J
2007-07-01
This paper describes the introduction of a single-pass batch hemodialysis system for renal replacement therapy in a 14 bed intensive care unit. The goals were to reduce the workload of intensive care unit physicians using an alternative and simpler method compared to continuous veno-venous hemodiafiltration (CVVHDF) and to reduce the costs of hemofiltrate solutions (80,650 EUR per year in our clinic in 2005). We describe and evaluate the process of implementation of the system as well as the achieved and prospective savings. We conclude that a close cooperation of all participants (physicians, nurses, economists, technicians) of a hospital can achieve substantial benefits for patients and employees as well as reduce the economic burden of a hospital.
Magnetic resonance of rubidium atoms passing through a multi-layered transmission magnetic grating
International Nuclear Information System (INIS)
Nagata, Y; Kurokawa, S; Hatakeyama, A
2017-01-01
We measured the magnetic resonance of rubidium atoms passing through periodic magnetic fields generated by two types of multi-layered transmission magnetic grating. One of the gratings reported here was assembled by stacking four layers of magnetic films so that the direction of magnetization alternated at each level. The other grating was assembled so that the magnetization at each level was aligned. For both types of grating, the experimental results were in good agreement with our calculations. We studied the feasibility of extending the frequency band of the grating and narrowing its resonance linewidth by performing calculations. For magnetic resonance precision spectroscopy, we conclude that the multi-layered transmission magnetic grating can generate periodic fields with narrower linewidths at higher frequencies when a larger number of layers are assembled at a shorter period length. Moreover, the frequency band of this type of grating can potentially achieve frequencies of up to hundreds of PHz. (paper)
A Computer Program for Flow-Log Analysis of Single Holes (FLASH)
Day-Lewis, F. D.; Johnson, C.D.; Paillet, Frederick L.; Halford, K.J.
2011-01-01
A new computer program, FLASH (Flow-Log Analysis of Single Holes), is presented for the analysis of borehole vertical flow logs. The code is based on an analytical solution for steady-state multilayer radial flow to a borehole. The code includes options for (1) discrete fractures and (2) multilayer aquifers. Given vertical flow profiles collected under both ambient and stressed (pumping or injection) conditions, the user can estimate fracture (or layer) transmissivities and far-field hydraulic heads. FLASH is coded in Microsoft Excel with Visual Basic for Applications routines. The code supports manual and automated model calibration. ?? 2011, The Author(s). Ground Water ?? 2011, National Ground Water Association.
International Nuclear Information System (INIS)
Nguyen, S.N.; Weed, H.C.; Leider, H.R.; Stout, R.B.
1991-10-01
The modelling of radionuclide release from waste forms is an important part of the performance assessment of a potential, high-level radioactive waste repository. Since spent fuel consists of UO 2 containing actinide elements and other fission products, it is necessary to determine the principal parameters affecting UO 2 dissolution and quantify their effects on the dissolution rate before any prediction of long term release rates of radionuclides from the spent fuel can be made. As part of a complex matrix to determine the dissolution kinetics of UO 2 as a function of time, pH, carbonate/bicarbonate concentration and oxygen activity, we have measured the dissolution rates at 25 degrees C of: (1) UO 2 pellets; (2) UO 2.00 powder and (3) synthetic dehydrated schoepite, UO 3 .H 2 O using a single-pass flow through system in an argon-atmosphere glove box. Carbonate, carbonate/bicarbonate, and bicarbonate buffers with concentrations ranging from 0.0002 M to 0.02 M and pH values form 8 to 11 have been used. Argon gas mixtures containing oxygen (from 0.002 to 0.2 atm) and carbon dioxide (from 0 to 0.011 atm) were bubbled through the buffers to stabilize their pH values. 12 refs., 2 tabs
Preparation and initial characterization of fluidized bed steam reforming pure-phase standards
Energy Technology Data Exchange (ETDEWEB)
Missimer, D. M.; Rutherford, R. L.
2013-03-21
Hanford is investigating the Fluidized Bed Steam Reforming (FBSR) process for their Low Activity Waste. The FBSR process offers a low-temperature continuous method by which liquid waste can be processed with the addition of clay into a sodium aluminosilicate (NAS) waste form. The NAS waste form is mainly comprised of nepheline (NaAlSiO{sub 4}), sodalite (Na{sub 8}[AlSiO{sub 4}]{sub 6}Cl{sub 2}), and nosean (Na{sub 8}[AlSiO{sub 4}]{sub 6}SO{sub 4}). Anions such as perrhenate (ReO{sub 4}{sup -}), pertechnetate (TcO{sub 4}{sup -}), and iodine (I{sup -}) are expected to replace sulfate in the nosean structure and/or chloride in the sodalite mineral structure (atomically bonded inside the aluminosilicate cages that these mineral structures possess). In the FBSR waste form, each of these phases can exist in a variety of solid solutions that differ from the idealized forms observed in single crystals in nature. The lack of understanding of the durability of these stoichiometric or idealized mineral phases complicates the ability to deconvolute the durability of the mixed phase FBSR product since it is a combination of different NAS phases. To better understand the behavior, fabrication and testing of the individual phases of the FBSR product is required. Analytical Development (AD) of the Science and Technology directorate of the Savannah River National Laboratory (SRNL) was requested to prepare the series of phase-pure standards, consisting of nepheline, nosean, and Cl, Re, and I sodalite. Once prepared, X-ray Diffraction (XRD) analyses were used to confirm the products were phase pure. These standards are being used for subsequent characterization studies consisting of the following: single-pass flow-through (SPFT) testing, development of thermodynamic data, and x-ray diffraction (XRD) calibration curves. In addition to the above mentioned phase-pure standards, AD was tasked with fabricating a mixed Tc-Re sodalite.
Choked flow mechanism of HFC-134a flowing through short-tube orifices
Energy Technology Data Exchange (ETDEWEB)
Nilpueng, Kitti; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok (Thailand)
2011-02-15
This paper is a continuation of the author's previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube orifices under choked flow condition are presented. Short-tube orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a miniature vapour-compression refrigeration system are examined. The experimental results indicated that the occurrence of choked flow phenomena inside short-tube orifices is different from that obtained from short-tube orifice diameters of greater than 1 mm, which are typically used in air-conditioner. The beginning of choked flow is dependent on the downstream pressure, degree of subcooling, and length-to-diameter ratio. Under choked flow condition, the mass flow rate is greatly varied with the short-tube orifice dimension, but it is slightly affected by the operating conditions. A correlation of mass flow rate through short-tube orifices is proposed in terms of the dimensionless parameters. The predicted results show good agreement with experimental data with a mean deviation of 4.69%. (author) transfer coefficient was also proposed. (author)
Energy Technology Data Exchange (ETDEWEB)
Herbert, P. [AaF-Energikonsult Stockholm AB, (Sweden)
1995-02-01
For various reasons, extra by-passes are installed in district heating networks to ensure a high flow temperature when the water circulation is insufficient. By `extra by-pass` we here mean a connection between the distribution pipe and the return pipe. This study mainly deals with extra by-passes to prevent freezing. The estimation of the extra by-pass costs is based on the district heating rates. Our assumption is that an extra by-pass can be regarded as a substation in the district heating network, with regard to the demand for the water flow, heat and power. The reason is the difficulty to obtain available facts to estimate the real costs concerning extra by-passes. Therefore, the method can not claim that the information about the costs is exact but gives an indication of the size of them. The valves in an extra by-pass can be set more or less open. We assume that manual valves in extra by-passes are wide open. Thermostatic valves are, however, assumed to be adjusted in order to cause a very small water flow. 2 refs, 16 figs, 9 tabs, 6 appendices
Energy recovery from air flow in underground railway systems
Energy Technology Data Exchange (ETDEWEB)
Morrone, B.; Mariani, A. [Seconda Univ. degli studi di Napoli, Aversa (Italy). Dept. of Aerospace and Mechanical Engineering; Costanzo, M.L. [Tecnosistem spa, Napoli (Italy)
2010-07-01
The 20-20-20 energy policy of the European Union commits members to reduce carbon dioxide (CO{sub 2}) emissions by 20 per cent by 2020, and stipulates that 20 per cent of final-use energy is to be supplied by renewable energy sources. This paper proposed the concept of recovering energy from underground trains by using the air flow inside tunnels to drive energy conversion systems such as turbines to generate electricity. Underground trains use much of their power to overcome the aerodynamic resistance moving the air in front of the train, creating a piston effect when travelling inside tunnels at relatively low speed. Numerical simulations were used in this study to determine how much electricity could be produced. A one-dimensional numerical analysis of a specific subway train track was used to evaluate the air flow magnitude inside the tunnel. Once the air flow features were detected, the potential electricity production was evaluated by considering the characteristics of a Wells turbine. Two types of 3-dimensional models of the tunnel and train were presented. One considered a long straight tunnel with a train running in it, and a small portion of a bypass tunnel. The other considered a large part of an opposite tunnel connected to the main one through the by-pass tunnel. Both the 3D models revealed a maximum flow rate of 2.5 x 105 m{sup 3}/h, while the 1D model showed an air flow of 1.5 x 105 m{sup 3}/h. The difference was due primarily to the presence of fans in the 1D Model and different modelling assumptions. It was concluded that one single Wells type turbine placed in a by-pass tunnel can produce 32.6 kWh per day, or about 10 MWh per year, resulting in a CO{sub 2} savings of about 5.5 tons per year. 8 refs., 1 tab., 11 figs.
Single-molecule electron tunnelling through multiple redox levels with environmental relaxation
DEFF Research Database (Denmark)
Kuznetsov, A.M.; Ulstrup, Jens
2004-01-01
represent the substrate and tip in electrochemical in situ scanning tunnelling microscopy. An equivalent three-electrode configuration represents a molecular single-electron transistor in which the enclosing electrodes constitute source and drain, and the reference electrode the gate. Current-bias voltage...... relations at fixed electrochemical overpotential or gate voltage, and current-overpotential or current-gate voltage relations at fixed bias voltage are equivalent in the two systems. Due to the activation-less nature of the processes, electron flow between the electrodes through the molecular redox levels...... level(s) subsequent to electron transfer. Several physical mechanisms can be distinguished and distinctive current-overpotential/gate voltage or current-bias voltage relations obtained. These reflect electronic level separation, environmental nuclear reorganisation, and coherent or incoherent multi...
Helping Students with Difficult First Year Subjects through the PASS Program
Sultan, Fauziah K. P. D.; Narayansany, Kannaki S.; Kee, Hooi Ling; Kuan, Chin Hoay; Palaniappa Manickam, M. Kamala; Tee, Meng Yew
2013-01-01
The purpose of this action research was to find out if participants of a pilot PASS program found it to be helpful. The program was implemented for the first time in an institute of higher learning in Malaysia. An action research design guided the study, with surveys, documents, and reflections as primary data sources. The findings were largely…
Measurement of flow fluctuations in single longitudinal mode pulsed ...
Indian Academy of Sciences (India)
2014-02-12
Feb 12, 2014 ... Page 1 ... Keywords. Dye lasers; single longitudinal mode; flow fluctuations. PACS Nos 42.55.Mv; 42.60.Mi; 42.60.By. 1. Introduction. Narrow-band dye lasers offer ... stabilized tunable laser source plays an important role for many applications as mentioned above [1]. For tight wavelength control, the ...
A new approach to sum frequency generation of single-frequency blue light in a coupled ring cavity
DEFF Research Database (Denmark)
Jensen, Ole Bjarlin; Petersen, Paul Michael
2014-01-01
We present a generic approach for the generation of tunable single-frequency light and demonstrate generation of more than 300 mW tunable light around 460 nm. One tapered diode laser is operated in a coupled ring cavity containing the nonlinear crystal and another tapered diode laser is sent thro...... through the nonlinear crystal in a single pass. A high conversion efficiency of more than 25 % of the single-pass laser is enabled by the high circulating power in the coupled cavity. The system is entirely self-stabilized with no need for electronic locking....
Compartment in vertical flow reactor for ferruginous mine water
Hur, Won; Cheong, Young-Wook; Yim, Gil-Jae; Ji, Sang-Woo; Hong, Ji-Hye
2014-05-01
Mine effluents contain varying concentrations of ferrous ion along with other metal ions. Fe(II) that quickly oxidizes to form precipitates in the presence of oxygen under net alkaline or neutral conditions. Thus, passive treatment methods are designed for the mine water to reside in an open containment area so as to allow simultaneous oxidation and precipitation of Fe(II), such as in a lagoon or an oxidation pond. A vertical flow reactor (VFR) was also suggested to remediate ferruginous mine drainage passing down through an accreting bed of ochre. However, VFR has a limited operation time until the system begins to overflow. It was also demonstrated that two-compartment VFR has a longer operation time than single compartment VFR of same size. In this study, a mathematical model was developed as a part of efforts to explore the operation of VFR, showing dynamic changes in head differences, ochre depth and Fe(II)/Fe(III) concentration in the effluent flow. The analysis shows that Fe(II) oxidation and ochre formation should be balanced with permeability of ochre bed to maximize VFR operation time and minimize residual Fe(II) in the effluent. The model demonstrates that two compartment VFR can have a longer operation time than a single-compartment VFR and that an optimum compartment ratio exists that maximize VFR operation time. Accelerated Fe(II) oxidation significantly affects the optimum ratio of compartment area and reduced residual Fe(II) in the effluent. VFR operation time can be significantly prolonged by increasing the rate of ochre formation not by accelerated Fe(II) oxidation. Taken together, ochre forms largely in the first compartment while overflowed mine water with reduced iron contents is efficiently filtered in the second compartment. These results provide us a better understanding of VFR operation and optimum design criteria for maximum operation time in a two-compartment VFR. Rapid ochre accretion in the first compartment maintains constant hydraulic
Gao, B.; Smits, K. M.
2017-12-01
Evaporation is a strongly coupled exchange process of mass, momentum and energy between the atmosphere and the soil. Several mechanisms influence evaporation, such as the atmospheric conditions, the structure of the soil surface, and the physical properties of the soil. Among the previous studies associated with evaporation modeling, most efforts use uncoupled models which simplify the influences of the atmosphere and soil through the use of resistance terms. Those that do consider the coupling between the free flow and porous media flow mainly consider flat terrain with grain-scale roughness. However, larger obstacles, which may form drags or ridges allowing normal convective air flow through the soil, are common in nature and may affect the evaporation significantly. Therefore, the goal of this work is to study the influence of large obstacles such as wavy surfaces on the flow behavior within the soil and exchange processes to the atmosphere under turbulent free-flow conditions. For simplicity, the soil surface with large obstacles are represented by a simple wavy surface. To do this, we modified a previously developed theory for two-phase two-component porous-medium flow, coupling it to single-phase two-component turbulent flow to simulate and analyze the evaporation from wavy soil surfaces. Detailed laboratory scale experiments using a wind tunnel interfaced with a porous media tank were carried out to test the modeling results. The characteristics of turbulent flow across a permeable wavy surface are discussed. Results demonstrate that there is an obvious recirculation zone formed at the surface, which is special because of the accumulation of water vapor and the thicker boundary layer in this area. In addition, the influences of both the free flow and porous medium on the evaporation are also analyzed. The porous medium affects the evaporation through the amount of water it can provide to the soil surface; while the atmosphere influences the evaporation
Directory of Open Access Journals (Sweden)
Snorri Donaldsson
Full Text Available The ability to determine airflow during nasal CPAP (NCPAP treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing.Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically.The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance.The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.
Intracardiac flow patterns studied by cine MR flow imaging
International Nuclear Information System (INIS)
Underwood, S.R.; Firmin, D.N.; Klipstein, R.H.; Rees, R.S.O.; Longmore, D.B.
1986-01-01
Velocity mapping by means of cine-MR imaging allows accurate measurement of velocity and flow within the cardiovascular system. A cine display and color coding simplify interpretation. The author have used the technique in a variety of patients to illustrate its potential. Velocity mapping in coronary artery by pass grafts in six patients provided a measure of graft function. Coronary artery velocities were measured in three subjects. Flow was measured through defects in the atrial septum, the ventricular septum, and a Gerbode defect. Velocity was reduced distal to coarctation of the aorta and was increased at the level of a partial venous occlusion by thrombosis. In a patient with isomerism, velocity mapping in the central vessels aided interpretation. Cine-MR imaging velocity mapping combined with conventional imaging yields important functional information on the cardiovascular system
An experimental investigation of turbulent flow heat transfer through ...
African Journals Online (AJOL)
An experimental investigation has been carried out to study the turbulent flow heat transfer and to determine the pressure drop characteristics of air, flowing through a tube with insert. An insert of special geometry is used inside the tube. The test section is electrically heated, and air is allowed to flow as the working fluid ...
Three mechanisms model of shale gas in real state transport through a single nanopore
Li, Dongdong; Zhang, Yanyu; Sun, Xiaofei; Li, Peng; Zhao, Fengkai
2018-02-01
At present, the apparent permeability models of shale gas consider only the viscous flow and Knudsen diffusion of free gas, but do not take into account the influence of surface diffusion. Moreover, it is assumed that shale gas is in ideal state. In this paper, shale gas is assumed in real state, a new apparent permeability model for shale gas transport through a single nanopore is developed that captures many important migration mechanisms, such as viscous flow and Knudsen diffusion of free gas, surface diffusion of adsorbed gas. According to experimental data, the accuracy of apparent permeability model was verified. What’s more, the effects of pressure and pore radius on apparent permeability, and the effects on the permeability fraction of viscous flow, Knudsen diffusion and surface diffusion were analysed, separately. Finally, the results indicate that the error of the developed model in this paper was 3.02%, which is less than the existing models. Pressure and pore radius seriously affect the apparent permeability of shale gas. When the pore radius is small or pressure is low, the surface diffusion cannot be ignored. When the pressure and the pore radius is big, the viscous flow occupies the main position.
International Nuclear Information System (INIS)
Nagel, H.
1986-01-01
The flow induced valve operation is calculated for single and two-phase flow conditions by the fluid dynamic computer code DYVRO and results are compared to experimental data. The analysis show that the operational behaviour of the valves is not only dependent on the condition of the induced flow, but also the pipe flow can cause a feedback as a result of the induced pressure waves. For the calculation of pressure wave propagation in pipes of which the operation of flow induced valves has a considerable influence it is therefore necessary to have a coupled analysis of the pressure wave propagation and the operational behaviour of the valves. The analyses of the fast transient transfer from steam to two-phase flow show a good agreement with experimental data. Hence even these very high loads on pipes resulting from such fluid dynamic transients can be calculated realistically. (orig.)
Analysis of Biomechanical Structure and Passing Techniques in Basketball
Directory of Open Access Journals (Sweden)
Ricardo E. Izzo
2011-06-01
Full Text Available The basketball is a complex sport, which these days has become increasingly linked to its’ psychophysical aspects rather than to the technical ones. Therefore, it is important to make a through study of the passing techniques from the point of view of the type of the pass and its’ biomechanics. From the point of view of the type of the used passes, the most used is the two-handed chest pass with a frequency of 39.9%. This is followed, in terms of frequency, by one-handed passes – the baseball, with 20.9 % – and by the two-handed over the head pass, with 18.2 %, and finally, one- or two-handed indirect passes (bounces, with 11.2 % and 9.8 %. Considering the most used pass in basketball, from the biomechanical point of view, the muscles involved in the correct movement consider all the muscles of the upper extremity, adding also the shoulder muscles as well as the body fixators (abdominals, hip flexors, knee extensors, and dorsal flexors of the foot. The technical and conditional analysis considers the throwing speed, the throw height and the air resistance. In conclusion, the aim of this study is to give some guidelines to improve the mechanical execution of the movements in training, without neglecting the importance of the harmony of the movements themselves.
Spanish validation of the Premorbid Adjustment Scale (PAS-S).
Barajas, Ana; Ochoa, Susana; Baños, Iris; Dolz, Montse; Villalta-Gil, Victoria; Vilaplana, Miriam; Autonell, Jaume; Sánchez, Bernardo; Cervilla, Jorge A; Foix, Alexandrina; Obiols, Jordi E; Haro, Josep Maria; Usall, Judith
2013-02-01
The Premorbid Adjustment Scale (PAS) has been the most widely used scale to quantify premorbid status in schizophrenia, coming to be regarded as the gold standard of retrospective assessment instruments. To examine the psychometric properties of the Spanish version of the PAS (PAS-S). Retrospective study of 140 individuals experiencing a first episode of psychosis (n=77) and individuals who have schizophrenia (n=63), both adult and adolescent patients. Data were collected through a socio-demographic questionnaire and a battery of instruments which includes the following scales: PAS-S, PANSS, LSP, GAF and DAS-sv. The Cronbach's alpha was performed to assess the internal consistency of PAS-S. Pearson's correlations were performed to assess the convergent and discriminant validity. The Cronbach's alpha of the PAS-S scale was 0.85. The correlation between social PAS-S and total PAS-S was 0.85 (p<0.001); while for academic PAS-S and total PAS-S it was 0.53 (p<0.001). Significant correlations were observed between all the scores of each age period evaluated across the PAS-S scale, with a significance value less than 0.001. There was a relationship between negative symptoms and social PAS-S (0.20, p<0.05) and total PAS-S (0.22, p<0.05), but not with academic PAS-S. However, there was a correlation between academic PAS-S and general subscale of the PANSS (0.19, p<0.05). Social PAS-S was related to disability measures (DAS-sv); and academic PAS-S showed discriminant validity with most of the variables of social functioning. PAS-S did not show association with the total LSP scale (discriminant validity). The Spanish version of the Premorbid Adjustment Scale showed appropriate psychometric properties in patients experiencing a first episode of psychosis and who have a chronic evolution of the illness. Moreover, each domain of the PAS-S (social and academic premorbid functioning) showed a differential relationship to other characteristics such as psychotic symptoms, disability
International Nuclear Information System (INIS)
Kim, Jeong Hun; Kim, Jin Hyoung; Yu, Young Suk; Kim, Kyu-Won; Kim, Myung Hun
2009-01-01
The retina maintains homeostasis through the blood-retinal barrier (BRB). Although it is ideal to deliver the drug to the retina via systemic administration, it is still challenging due to the BRB strictly regulating permeation from blood to the retina. Herein, we demonstrated that intravenously administered gold nanoparticles could pass through the BRB and are distributed in all retinal layers without cytotoxicity. After intravenous injection of gold nanoparticles into C57BL/6 mice, 100 nm nanoparticles were not detected in the retina whereas 20 nm nanoparticles passed through the BRB and were distributed in all retinal layers. 20 nm nanoparticles in the retina were observed in neurons (75 ± 5%), endothelial cells (17 ± 6%) and peri-endothelial glial cells (8 ± 3%), where nanoparticles were bound on the membrane. In the retina, cells containing nanoparticles did not show any structural abnormality and increase of cell death compared to cells without nanoparticles. Gold nanoparticles never affected the viability of retinal endothelial cells, astrocytes and retinoblastoma cells. Furthermore, gold nanoparticles never led to any change in expression of representative biological molecules including zonula occludens-1 and glut-1 in retinal endothelial cells, neurofilaments in differentiated retinoblastoma cells and glial fibrillary acidic protein in astrocytes. Therefore, our data suggests that small gold nanoparticles (20 nm) could be an alternative for drug delivery across the BRB, which could be safely applied in vivo.
Energy Technology Data Exchange (ETDEWEB)
Kim, Jeong Hun; Kim, Jin Hyoung; Yu, Young Suk [Department of Ophthalmology, Seoul National University College of Medicine and Seoul Artificial Eye Center, Clinical Research Institute, Seoul National University Hospital, Seoul 151744 (Korea, Republic of); Kim, Kyu-Won [NeuroVascular Coordination Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151742 (Korea, Republic of); Kim, Myung Hun, E-mail: hunin315@paran.com, E-mail: ysyu@snu.ac.kr [Department of Chemistry, Yonsei University, 134 Shinchon-dong, Seodaemun-ku, Seoul 120749 (Korea, Republic of)
2009-12-16
The retina maintains homeostasis through the blood-retinal barrier (BRB). Although it is ideal to deliver the drug to the retina via systemic administration, it is still challenging due to the BRB strictly regulating permeation from blood to the retina. Herein, we demonstrated that intravenously administered gold nanoparticles could pass through the BRB and are distributed in all retinal layers without cytotoxicity. After intravenous injection of gold nanoparticles into C57BL/6 mice, 100 nm nanoparticles were not detected in the retina whereas 20 nm nanoparticles passed through the BRB and were distributed in all retinal layers. 20 nm nanoparticles in the retina were observed in neurons (75 {+-} 5%), endothelial cells (17 {+-} 6%) and peri-endothelial glial cells (8 {+-} 3%), where nanoparticles were bound on the membrane. In the retina, cells containing nanoparticles did not show any structural abnormality and increase of cell death compared to cells without nanoparticles. Gold nanoparticles never affected the viability of retinal endothelial cells, astrocytes and retinoblastoma cells. Furthermore, gold nanoparticles never led to any change in expression of representative biological molecules including zonula occludens-1 and glut-1 in retinal endothelial cells, neurofilaments in differentiated retinoblastoma cells and glial fibrillary acidic protein in astrocytes. Therefore, our data suggests that small gold nanoparticles (20 nm) could be an alternative for drug delivery across the BRB, which could be safely applied in vivo.
Zhu, Chen-Xi; Wang, Chi-Chuan
2018-01-01
This study proposes a numerical model for plate heat exchanger that is capable of handling supercritical CO2 fluid. The plate heat exchangers under investigation include Z-type (1-pass), U-type (1-pass), and 1-2 pass configurations. The plate spacing is 2.9 mm with a plate thickness of 0.8 mm, and the size of the plate is 600 mm wide and 218 mm in height with 60 degrees chevron angle. The proposed model takes into account the influence of gigantic change of CO2 properties. The simulation is first compared with some existing data for water-to-water plate heat exchangers with good agreements. The flow distribution, pressure drop, and heat transfer performance subject to the supercritical CO2 in plate heat exchangers are then investigated. It is found that the flow velocity increases consecutively from the entrance plate toward the last plate for the Z-type arrangement, and this is applicable for either water side or CO2 side. However, the flow distribution of the U-type arrangement in the water side shows opposite trend. Conversely, the flow distribution for U-type arrangement of CO2 depends on the specific flow ratio (C*). A lower C* like 0.1 may reverse the distribution, i.e. the flow velocity increases moderately alongside the plate channel like Z-type while a large C* of 1 would resemble the typical distribution in water channel. The flow distribution of CO2 side at the first and last plate shows a pronounced drop/surge phenomenon while the channels in water side does not reveal this kind of behavior. The performance of 2-pass plate heat exchanger, in terms of heat transfer rate, is better than that of 1-pass design only when C* is comparatively small (C* < 0.5). Multi-pass design is more effective when the dominant thermal resistance falls in the CO2 side.
Vye-Brown, C.; Gannoun, A.; Barry, T. L.; Self, S.; Burton, K. W.
2013-04-01
Geochemical interpretations of continental flood basalts usually assume that individual lava flows represent compositionally homogenous and rapidly erupted products of large well-mixed magma reservoirs. However, inflated pāhoehoe lavas may develop over considerable periods of time and preserve chemical variations that can be temporally linked through flow formation to eruption sequence thus providing an understanding of magma evolution over the timescale of a single eruption. This study presents comprehensive major, trace element and Re-Os isotope data for a single eruption that formed the 2660 km3 Sand Hollow flow field in the Columbia River Basalt Province, USA. Major and trace element variations accompanying flow emplacement (e.g. MgO 3.09-4.55 wt%, Ni 17.5-25.6 ppm) are consistent with fractional crystallisation, but other petrogenetic processes or variable sources cannot be distinguished. However, there is a systematic shift in the initial 187Os/188Os isotope composition of the magma (age corrected to 15.27 Ma), from 0.174 (lava core) to 1.444 (lava crust) within a single 35 m thick sheet lobe. Lava crust values are more radiogenic than any known mantle source, consistent with previous data indicating that neither an enriched reservoir nor the sub-continental lithospheric mantle are likely to have sourced these basalts. Rather, these data indicate that lavas emplaced during the earliest stages of eruption have higher degrees of crustal contamination. These results highlight the limitations of applying chemostratigraphic correlation across continental flood basalt provinces, the use of single data points to define melt sources and magmatic processes, and the dangers of using conventional isochron techniques in such basalt sequences for absolute chronology.
Passing and Catching in Rugby.
Namudu, Mike M.
This booklet contains the fundamentals for rugby at the primary school level. It deals primarily with passing and catching the ball. It contains instructions on (1) holding the ball for passing, (2) passing the ball to the left--standing, (3) passing the ball to the left--running, (4) making a switch pass, (5) the scrum half's normal pass, (6) the…
Gorelick, Marc H; Stevens, Molly W; Schultz, Theresa R; Scribano, Philip V
2004-01-01
To evaluate the reliability, validity, and responsiveness of a new clinical asthma score, the Pediatric Asthma Severity Score (PASS), in children aged 1 through 18 years in an acute clinical setting. This was a prospective cohort study of children treated for acute asthma at two urban pediatric emergency departments (EDs). A total of 852 patients were enrolled at one site and 369 at the second site. Clinical findings were assessed at the start of the ED visit, after one hour of treatment, and at the time of disposition. Peak expiratory flow rate (PEFR) (for patients aged 6 years and older) and pulse oximetry were also measured. Composite scores including three, four, or five clinical findings were evaluated, and the three-item score (wheezing, prolonged expiration, and work of breathing) was selected as the PASS. Interobserver reliability for the PASS was good to excellent (kappa = 0.72 to 0.83). There was a significant correlation between PASS and PEFR (r = 0.27 to 0.37) and pulse oximetry (r = 0.29 to 0.41) at various time points. The PASS was able to discriminate between those patients who did and did not require hospitalization, with area under the receiver operating characteristic curve of 0.82. Finally, the PASS was shown to be responsive, with a 48% relative increase in score from start to end of treatment and an overall effect size of 0.62, indicating a moderate to large effect. This clinical score, the PASS, based on three clinical findings, is a reliable and valid measure of asthma severity in children and shows both discriminative and responsive properties. The PASS may be a useful tool to assess acute asthma severity for clinical and research purposes.
Flow visualization through metal enclosures with neutron radiography
International Nuclear Information System (INIS)
Cimbala, J.M.; Sathianathan, D.; Cosgrove, S.A.
1989-01-01
Many practical fluid flow problems involve flow inside metal shrouds (valves, combustors, boilers, turbomachinery, etc.) where visual access is not available. For flows under extreme pressure or heat, glass or transparent plastic can not be used; a flow visualization technique which permits visualization through metal containers is needed in these cases. Since neutrons can penetrate metal casings, neutron radiography has been developed for application to fluid flow visualization. This technique involves imaging of neutron opaque tracer materials, such as solid or fluid particles or streaklines, as they convect in neutron transparent ambient fluids. Surface flow visualization is also possible by using neutron opaque tufts. An extension of the surface tuft technique has also been developed, enabling the visualization of flow a patterns away from solid surfaces. This paper presents a summary of the various flow visualization techniques developed in the authors' laboratory, along with examples which illustrate how these techniques may be applied to practical fluid flow problems. These include flow over a circular cylinder, the recirculation pattern formed by a jet exhausting into a tank, and the flow pattern inside a rotating automotive torque converter
Simulation of blood flow through an artificial heart
Kiris, Cetin; Chang, I-Dee; Rogers, Stuart E.; Kwak, Dochan
1991-01-01
A numerical simulation of the incompressible viscous flow through a prosthetic tilting disk heart valve is presented in order to demonstrate the current capability to model unsteady flows with moving boundaries. Both steady state and unsteady flow calculations are done by solving the incompressible Navier-Stokes equations in 3-D generalized curvilinear coordinates. In order to handle the moving boundary problems, the chimera grid embedding scheme which decomposes a complex computational domain into several simple subdomains is used. An algebraic turbulence model for internal flows is incorporated to reach the physiological values of Reynolds number. Good agreement is obtained between the numerical results and experimental measurements. It is found that the tilting disk valve causes large regions of separated flow, and regions of high shear.
Soltani, M; Chen, P
2013-01-01
Modeling of interstitial fluid flow involves processes such as fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. To date, majority of microvascular flow modeling has been done at different levels and scales mostly on simple tumor shapes with their capillaries. However, with our proposed numerical model, more complex and realistic tumor shapes and capillary networks can be studied. Both blood flow through a capillary network, which is induced by a solid tumor, and fluid flow in tumor's surrounding tissue are formulated. First, governing equations of angiogenesis are implemented to specify the different domains for the network and interstitium. Then, governing equations for flow modeling are introduced for different domains. The conservation laws for mass and momentum (including continuity equation, Darcy's law for tissue, and simplified Navier-Stokes equation for blood flow through capillaries) are used for simulating interstitial and intravascular flows and Starling's law is used for closing this system of equations and coupling the intravascular and extravascular flows. This is the first study of flow modeling in solid tumors to naturalistically couple intravascular and extravascular flow through a network. This network is generated by sprouting angiogenesis and consisting of one parent vessel connected to the network while taking into account the non-continuous behavior of blood, adaptability of capillary diameter to hemodynamics and metabolic stimuli, non-Newtonian blood flow, and phase separation of blood flow in capillary bifurcation. The incorporation of the outlined components beyond the previous models provides a more realistic prediction of interstitial fluid flow pattern in solid tumors and surrounding tissues. Results predict higher interstitial pressure, almost two times, for realistic model compared to the simplified model.
Directory of Open Access Journals (Sweden)
M Soltani
Full Text Available Modeling of interstitial fluid flow involves processes such as fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. To date, majority of microvascular flow modeling has been done at different levels and scales mostly on simple tumor shapes with their capillaries. However, with our proposed numerical model, more complex and realistic tumor shapes and capillary networks can be studied. Both blood flow through a capillary network, which is induced by a solid tumor, and fluid flow in tumor's surrounding tissue are formulated. First, governing equations of angiogenesis are implemented to specify the different domains for the network and interstitium. Then, governing equations for flow modeling are introduced for different domains. The conservation laws for mass and momentum (including continuity equation, Darcy's law for tissue, and simplified Navier-Stokes equation for blood flow through capillaries are used for simulating interstitial and intravascular flows and Starling's law is used for closing this system of equations and coupling the intravascular and extravascular flows. This is the first study of flow modeling in solid tumors to naturalistically couple intravascular and extravascular flow through a network. This network is generated by sprouting angiogenesis and consisting of one parent vessel connected to the network while taking into account the non-continuous behavior of blood, adaptability of capillary diameter to hemodynamics and metabolic stimuli, non-Newtonian blood flow, and phase separation of blood flow in capillary bifurcation. The incorporation of the outlined components beyond the previous models provides a more realistic prediction of interstitial fluid flow pattern in solid tumors and surrounding tissues. Results predict higher interstitial pressure, almost two times, for realistic model compared to the simplified model.
A double-pass interferometer for measurement of dimensional changes
International Nuclear Information System (INIS)
Ren, Dongmei; Lawton, K M; Miller, J A
2008-01-01
A double-pass interferometer was developed for measuring dimensional changes of materials in a nanoscale absolute interferometric dilatometer. This interferometer realized the double-ended measurement of a sample using a single-detection double-pass interference system. The nearly balanced design, in which the measurement beam and the reference beam have equal optical path lengths except for the path difference caused by the sample itself, makes this interferometer have high stability, which is verified by the measurement of a quasi-zero-length sample. The preliminary experiments and uncertainty analysis show that this interferometer should be able to measure dimensional changes with characteristic uncertainty at the nanometer level
POD-Galerkin Model for Incompressible Single-Phase Flow in Porous Media
Wang, Yi; Yu, Bo; Sun, Shuyu
2017-01-01
Fast prediction modeling via proper orthogonal decomposition method combined with Galerkin projection is applied to incompressible single-phase fluid flow in porous media. Cases for different configurations of porous media, boundary conditions
Common pass decentered annular ring resonator
Energy Technology Data Exchange (ETDEWEB)
Holmes, D. A.; Waite, T. R.
1985-04-30
An optical resonator having an annular cylindrical gain region for use in a chemical laser or the like in which two ring-shaped mirrors having substantially conical reflecting surfaces are spaced apart along a common axis of revolution of the respective conical surfaces. A central conical mirror reflects incident light directed along said axis radially outwardly to the reflecting surface of a first one of the ring-shaped mirrors. The radial light rays are reflected by the first ring mirror to the second ring mirror within an annular cylindrical volume concentric with said common axis and forming a gain region. Light rays impinging on the second ring mirror are reflected to diametrically opposite points on the same conical mirror surfaces and back to the first ring mirror through the same annular cylindrical volume. The return rays are then reflected by the conical mirror surface of the first ring mirror back to the central conical mirror. The mirror surfaces are angled such that the return rays are reflected back along the common axis by the central mirror in a concentric annular cylindrical volume. A scraper mirror having a central opening centered on said axis and an offset opening reflects all but the rays passing through the two openings in an output beam. The rays passing through the second opening are reflected back through the first opening to provide feedback.
Comparative study of Newtonian physiological blood flow through normal and stenosed carotid artery
Rahman, Mohammad Matiur; Hossain, Md. Anwar; Mamun, Khairuzzaman; Akhter, Most. Nasrin
2017-06-01
A numerical simulation is performed to investigate Newtonian physiological flows behavior on three dimensional idealized carotid artery (CA) and single stenosed (75% by area) carotid artery(SCA). The wall vessel is set as rigid during simulation. Bifurcated blood vessel are simulated by using three-dimensional flow analysis. Physiological and parabolic velocity profiles are set out to fix the conditions of inlet boundaries of artery. In other hand, physiological waveform is an important part of compilation and it is successfully done by utilization of Fourier series having sixteen harmonics. The investigation has a Reynolds number range of 94 to 1120. Low Reynolds number k — ω model has been used as governing equation. The investigation has been carried out to characterize the flow behavior of blood in two geometry, namely, (i) Normal carotid artery (CA) and (ii) Stenosed carotid artery (SCA). The Newtonian model has been used to study the physics of fluid. The findings of the two models are thoroughly compared in order to observe there behavioral sequence of flows. The numerical results were presented in terms of velocity, pressure, wall shear stress distributions and cross sectional velocities as well as the streamlines contour. Stenosis disturbs the normal pattern of blood flow through the artery as reduced area. At stenosis region velocity and peak Reynolds number rapidly increase and Reynolds number reach transitional and turbulent region. These flow fluctuation and turbulence have bad effect to the blood vessel which makes to accelerate the progress of stenosis.
Schenker, M C; Pourquié, M J B M; Eskin, D G; Boersma, B J
2013-01-01
The flow in a confined container induced by an ultrasonic horn is measured by Particle Image Velocimetry (PIV). This flow is caused by acoustic streaming and highly influenced by the presence of cavitation. The jet-like experimentally observed flow is compared with the available theoretical solution for a turbulent free round jet. The similarity between both flows enables a simplified numerical model to be made, whilst the phenomenon is very difficult to simulate otherwise. The numerical model requires only two parameters, i.e. the flow momentum and turbulent kinetic energy at the position of the horn tip. The simulated flow is used as a basis for the calculation of the time required for the entire liquid volume to pass through the active cavitation region. Copyright © 2012 Elsevier B.V. All rights reserved.
Zhan, Yi; Fu, Guo; Zhou, Xiang; He, Bo; Yan, Li-Wei; Zhu, Qing-Tang; Gu, Li-Qiang; Liu, Xiao-Lin; Qi, Jian
2017-12-01
Complex extremity trauma commonly involves both soft tissue and vascular injuries. Traditional two-stage surgical repair may delay rehabilitation and functional recovery, as well as increase the risk of infections. We report a single-stage reconstructive surgical method that repairs soft tissue defects and vascular injuries with flow-through free flaps to improve functional outcomes. Between March 2010 and December 2016 in our hospital, 5 patients with severe upper extremity trauma received single-stage reconstructive surgery, in which a flow-through anterolateral thigh free flap was applied to repair soft tissue defects and vascular injuries simultaneously. Cases of injured artery were reconstructed with the distal trunk of the descending branch of the lateral circumflex femoral artery. A segment of adjacent vein was used if there was a second artery injury. Patients were followed to evaluate their functional recoveries, and received computed tomography angiography examinations to assess peripheral circulation. Two patients had post-operative thumb necrosis; one required amputation, and the other was healed after debridement and abdominal pedicle flap repair. The other 3 patients had no major complications (infection, necrosis) to the recipient or donor sites after surgery. All the patients had achieved satisfactory functional recovery by the end of the follow-up period. Computed tomography angiography showed adequate circulation in the peripheral vessels. The success of these cases shows that one-step reconstructive surgery with flow-through anterolateral thigh free flaps can be a safe and effective treatment option for patients with complex upper extremity trauma with soft tissue defects and vascular injuries. Copyright © 2017. Published by Elsevier Ltd.
Sea ice local surface topography from single-pass satellite InSAR measurements: a feasibility study
Directory of Open Access Journals (Sweden)
W. Dierking
2017-08-01
Full Text Available Quantitative parameters characterizing the sea ice surface topography are needed in geophysical investigations such as studies on atmosphere–ice interactions or sea ice mechanics. Recently, the use of space-borne single-pass interferometric synthetic aperture radar (InSAR for retrieving the ice surface topography has attracted notice among geophysicists. In this paper the potential of InSAR measurements is examined for several satellite configurations and radar frequencies, considering statistics of heights and widths of ice ridges as well as possible magnitudes of ice drift. It is shown that, theoretically, surface height variations can be retrieved with relative errors ≤ 0.5 m. In practice, however, the sea ice drift and open water leads may contribute significantly to the measured interferometric phase. Another essential factor is the dependence of the achievable interferometric baseline on the satellite orbit configurations. Possibilities to assess the influence of different factors on the measurement accuracy are demonstrated: signal-to-noise ratio, presence of a snow layer, and the penetration depth into the ice. Practical examples of sea surface height retrievals from bistatic SAR images collected during the TanDEM-X Science Phase are presented.
Contaminant flow and transport simulation in cracked porous media using locally conservative schemes
Song, Pu; Sun, Shuyu
2012-01-01
The purpose of this paper is to analyze some features of contaminant flow passing through cracked porous medium, such as the influence of fracture network on the advection and diffusion of contaminant species, the impact of adsorption on the overall
Radiation hardness tests of double-sided 3D strip sensors with passing-through columns
Energy Technology Data Exchange (ETDEWEB)
Dalla Betta, Gian-Franco, E-mail: gianfranco.dallabetta@unitn.it [Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, Via Sommarive 9, I-38123 Trento (Italy); INFN TIFPA, Via Sommarive 14, I-38123 Trento (Italy); Betancourt, Christopher [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Boscardin, Maurizio; Giacomini, Gabriele [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive 18, I-38123 Trento (Italy); Jakobs, Karl; Kühn, Susanne [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Lecini, Besnik [Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, Via Sommarive 9, I-38123 Trento (Italy); Mendicino, Roberto [Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, Via Sommarive 9, I-38123 Trento (Italy); INFN TIFPA, Via Sommarive 14, I-38123 Trento (Italy); Mori, Riccardo; Parzefall, Ulrich [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Povoli, Marco [Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, Via Sommarive 9, I-38123 Trento (Italy); Thomas, Maira [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Zorzi, Nicola [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive 18, I-38123 Trento (Italy)
2014-11-21
This paper deals with a radiation hardness study performed on double-sided 3D strip sensors with passing-through columns. Selected results from the characterization of the irradiated sensors with a beta source and a laser setup are reported and compared to pre-irradiation results and to TCAD simulations. The sensor performance in terms of signal efficiency is found to be in good agreement with that of other 3D sensors irradiated at the same fluences and tested under similar experimental conditions. - Highlights: • We report results from 3D silicon strip detectors irradiated up to HL-LHC fluences. • I–V curves, noise, charge collection measurements and laser scans are shown. • In all sensors, signals are distinguished from the noise already at low voltage. • Signal efficiency is in agreement with values expected from the electrode geometry. • Efficiency and spatial uniformity would benefit from higher operation voltages.
Integral benchmark for the attenuation of 14 MeV neutrons passing through lead layers
International Nuclear Information System (INIS)
Antonov, S.; Vojkov, G.; Ilieva, K.; Jordanova, J.
1987-01-01
The attenuation has been studied of the total 14 MeV neutron flux passing through an iron collimator and directly located behind lead slabs with thicknesses 2.5, 5.0, 7.5, 10.0 and 12.5 cm. A comparison is made between the calculated data and results from a benchmark experiment. The experiment is analysed with an one-dimensional model based on ANISN-code and a tree-dimentional model based on MORSE-code (Monte Carlo method). The energy dependences of the cross-sections and neutron fluxes are represented by a 25-group approximation based on the SUPERTOG program and the files ENDL and ENDF/B-4. The mean deviation of MORSE calculated data from experimental ones is 6.4% for ENDL-data and 8.5% for EDDF-data. ANISN-calculated data show practically full coincidence with experimental ones both for ENDL and ENDF
Radiation hardness tests of double-sided 3D strip sensors with passing-through columns
International Nuclear Information System (INIS)
Dalla Betta, Gian-Franco; Betancourt, Christopher; Boscardin, Maurizio; Giacomini, Gabriele; Jakobs, Karl; Kühn, Susanne; Lecini, Besnik; Mendicino, Roberto; Mori, Riccardo; Parzefall, Ulrich; Povoli, Marco; Thomas, Maira; Zorzi, Nicola
2014-01-01
This paper deals with a radiation hardness study performed on double-sided 3D strip sensors with passing-through columns. Selected results from the characterization of the irradiated sensors with a beta source and a laser setup are reported and compared to pre-irradiation results and to TCAD simulations. The sensor performance in terms of signal efficiency is found to be in good agreement with that of other 3D sensors irradiated at the same fluences and tested under similar experimental conditions. - Highlights: • We report results from 3D silicon strip detectors irradiated up to HL-LHC fluences. • I–V curves, noise, charge collection measurements and laser scans are shown. • In all sensors, signals are distinguished from the noise already at low voltage. • Signal efficiency is in agreement with values expected from the electrode geometry. • Efficiency and spatial uniformity would benefit from higher operation voltages
Modeling of air flow through a narrow crack
International Nuclear Information System (INIS)
Trojek, T.; Cechak, T.; Moucka, L.; Fronka, A.
2004-01-01
Radon transport in dwellings is governed to a significant extent by pressure differences and properties of transport pathways. A model of air flow through narrow cracks was created in order to facilitate prediction of air velocity and air flow. Theoretical calculations, based on numerical solution of a system of differential equations, were compared with measurements carried out on a window crack. (P.A.)
Flow through a Two-Scale Porosity Material
Directory of Open Access Journals (Sweden)
A. G. Andersson
2009-01-01
Full Text Available Flow through a two-scale porous medium is here investigated by a unique comparison between simulations performed with computational fluid dynamics and the boundary element method with microparticle image velocimetry in model geometries.
Directory of Open Access Journals (Sweden)
Andrey V. Tyukhtin
2007-05-01
Full Text Available The wakefields of a relativistic electron beam passing through a waveguide loaded with an active medium with weak resonant dispersion are considered. For the calculations in this paper, the parameters of the medium are those of a solution of fullerene (C_{60} in a nematic liquid crystal that exhibits activity in the X-band. It is shown that several of the TM accelerating modes can be amplified for the geometries under consideration; structures in which higher order modes are amplified exhibit essential advantages as PASERs. In particular, the amplification of the highest mode occurs in a structure loaded with a rather thick active medium layer that maximizes the energy stored by the active medium.
Numerical investigation of over expanded flow behavior in a single expansion ramp nozzle
Mousavi, Seyed Mahmood; Pourabidi, Reza; Goshtasbi-Rad, Ebrahim
2018-05-01
The single expansion ramp nozzle is severely over-expanded when the vehicle is at low speed, which hinders its ability to provide optimal configurations for combined cycle engines. The over-expansion leads to flow separation as a result of shock wave/boundary-layer interaction. Flow separation, and the presence of shocks themselves, result in a performance loss in the single expansion ramp nozzle, leading to reduced thrust and increased pressure losses. In the present work, the unsteady two dimensional compressible flow in an over expanded single expansion ramp nozzle has been investigated using finite volume code. To achieve this purpose, the Reynolds stress turbulence model and full multigrid initialization, in addition to the Smirnov's method for examining the errors accumulation, have been employed and the results are compared with available experimental data. The results show that the numerical code is capable of predicting the experimental data with high accuracy. Afterward, the effect of discontinuity jump in wall temperature as well as the length of straight ramp on flow behavior have been studied. It is concluded that variations in wall temperature and length of straight ramp change the shock wave boundary layer interaction, shock structure, shock strength as well as the distance between Lambda shocks.
The attenuation of temperature oscillations in passing through liquid metal boundary layers
International Nuclear Information System (INIS)
Lawn, C.J.
1975-08-01
One aspect of predicting the endurance of components subject to thermal fatigue in liquid metal cooled reactors is the extent to which oscillations in fluid temperature are transmitted to metal surfaces, such as the above-core structure. The first geometry considered is that of a solid plate in contact with a layer of stagnant fluid, in which temperature oscillations are imposed at a given distance from the plate. Transmission through a laminar boundary layer developing over the plate surface is then considered. An approximate calculation based on the slug-flow analysis of Sucec (1975) is developed. (U.K.)
International Nuclear Information System (INIS)
Imai, M.; Sataka, M.; Matsuda, M.; Okayasu, S.; Kawatsura, K.; Takahiro, K.; Komaki, K.; Shibata, H.; Nishio, K.
2015-01-01
Both equilibrium and non-equilibrium charge-state distributions were studied experimentally for 2.0 MeV/u carbon ions after passing through carbon foils. Measured charge-state distribution established the equilibrium at a target thickness of 10 μg/cm 2 and this remained unchanged until a maximum target thickness of 98 μg/cm 2 . The equilibrium charge-state distribution, the equilibrium mean charge-state, and the width and skewness of the equilibrium distribution were compared with predictions using existing semi-empirical formulae as well as simulation results, including the ETACHA code. It was found that charge-state distributions, mean charge states, and distribution widths for C 2+ , C 3+ , and C 4+ incident ions merged into quasi-equilibrium values at a target thickness of 5.7 μg/cm 2 in the pre-equilibrium region and evolved simultaneously to the ‘real equilibrium’ values for all of the initial charge states, including C 5+ and C 6+ ions, as previously demonstrated for sulfur projectile ions at the same velocity (Imai et al., 2009). Two kinds of simulation, ETACHA and solution of rate equations taking only single electron transfers into account, were used, and both of them reproduced the measured charge evolution qualitatively. The quasi-equilibrium behavior could be reproduced with the ETACHA code, but not with solution of elementary rate equations
International Nuclear Information System (INIS)
Obrutsky, L.; Cantin, M.; Renaud, J.; Cecco, V.; Lakhan, R.; Sullivan, S.
2000-01-01
A new generation of transmit-receive single-pass probes, denoted as C6 or X probe, was field tested during the Gentilly II, 2000 steam generator tube inspection. This probe has a performance equivalent to rotating probes and can be used for tubesheet and full-length inspection at an inspection speed equivalent to that of bobbin probes. Existing C3 transmit-receive probes have been demonstrated to be effective in detecting circumferential cracks. The C5 probe can detect both circumferential and axial cracks and volumetric defects but cannot discriminate between them. The C6 probe expands on the capabilities of both probes in a single probe head. It can simultaneously detect and discriminate between circumferential and axial cracks to satisfy different plugging criteria. It has excellent coverage, good defect detectability, and improved sizing and characterization. Probe data is displayed in C-scan format so that the amount of data to be analyzed is similar to rotating probes. The C6 probe will significantly decrease inspection time and the need for re-inspection and tube pulling. This paper describes the advantages of the probe and demonstrates its capabilities employing signals from tube samples with calibration flaws and laboratory induced cracks. It shows the results from the field trial of the probe at Gentilly II and describes the instrumentation, hardware and software used for the inspection. (author)
International Nuclear Information System (INIS)
Obrutsky, L.; Cantin, M.; Renaud, J.; Cecco, V.; Lakhan, R.; Sullivan, S.
2000-01-01
A new generation of transmit-receive single-pass probes, denoted as C6 or X probe, was field-tested during the Gentilly II, 2000 steam generator tube inspection. This probe has a performance equivalent to rotating probes and can be used for tubesheet and full-length inspection at an inspection speed equivalent to that of bobbin probes. Existing C3 transmit-receive probes have been demonstrated to be effective in detecting circumferential cracks. The C5 probe can detect both circumferential and axial cracks and volumetric defects but cannot discriminate between them. The C6 probe expands on the capabilities of both probes in a single probe head. It can simultaneously detect and discriminate between circumferential and axial cracks to satisfy different plugging criteria. It has excellent coverage, good defect detectability, and improved sizing and characterization. Probe data is displayed in C-scan format so that the amount of data to be analyzed is similar to rotating probes. The C6 probe will significantly decrease inspection time and the need for re-inspection and tube pulling. This paper describes the advantages of the probe and demonstrates its capabilities employing signals from tube samples with calibration flaws and laboratory induced cracks. It shows the results from the field trial of the probe at Gentilly II and describes the instrumentation, hardware and software used for the inspection. (author)
Buffels (Wes), Elsies, Sir Lowry's pass, Steenbras and Buffels (Oos)
CSIR Research Space (South Africa)
Heinecken, TJE
1982-06-01
Full Text Available This report is a synthesis of all available information on five of the smaller rivers discharging in to False bay combined as a single volume. The rivers dealt with are the Buffels (Wes), Elsies, Sir Lowry' Pass, Steenbras and Buffels (Oos). False...
Flooding Mechanism in Vertical Flow
International Nuclear Information System (INIS)
Ronny-Dwi Agussulistyo; Indarto
2000-01-01
This research was carried out to investigate the mechanism of flooding ina vertical liquid-gas counter current flow, along two meter length of thetube. The tube use both circular and square tube, a cross section of squaretube was made the same as a cross section of circular tube with one inchdiameter tube. The liquid enters the tube, passes through a porous wall inletand a groove inlet in a distributor and it flows downwards through a liquidoutlet in a collector. The gas is being introduced at the bottom of the tube,it flows upwards through nozzle in the collector. The results of researchshowed that the flooding occurs earlier in the circular tube than in thesquare tube, either uses a porous wall inlet or a groove inlet. In the squaretube , onset of the flooding occurs at the top of the tube, in front ofliquid injection, it is related to the formation of a film wave, just belowthe liquid feed. Whereas in the circular tube, onset of the flooding occursfrom the bottom of the tube, at the liquid outlet, it is related to theexpand of the film wave. However, in the circular tube with the groove inlet,for the higher liquid flow rate, onset of the flooding from the top, like inthe square tube. (author)
Thomas, D.; Garing, C.; Zahasky, C.; Harrison, A. L.; Bird, D. K.; Benson, S. M.; Oelkers, E. H.; Maher, K.
2017-12-01
Predicting the timing and magnitude of CO2 storage in basaltic rocks relies partly on quantifying the dependence of reactivity on flow path and mineral distribution. Flow-through experiments that use intact cores are advantageous because the spatial heterogeneity of pore space and reactive phases is preserved. Combining aqueous geochemical analyses and petrologic characterization with non-destructive imaging techniques (e.g. micro-computed tomography) constrains the relationship between irreversible reactions, pore connectivity and accessible surface area. Our work enhances these capabilities by dynamically imaging flow through vesicular basalts with Positron Emission Tomography (PET) scanning. PET highlights the path a fluid takes by detecting photons produced during radioactive decay of an injected radiotracer (FDG). We have performed single-phase, CO2-saturated flow-through experiments with basaltic core from Iceland at CO2 sequestration conditions (50 °C; 76-90 bar Ptot). Constant flow rate and continuous pressure measurements at the inlet and outlet of the core constrain permeability. We monitor geochemical evolution through cation and anion analysis of outlet fluid sampled periodically. Before and after reaction, we perform PET scans and characterize the core using micro-CT. The PET scans indicate a discrete, localized flow path that appears to be a micro-crack connecting vesicles, suggesting that vesicle-lining minerals are immediately accessible and important reactants. Rapid increases in aqueous cation concentration, pH and HCO3- indicate that the rock reacts nearly immediately after CO2 injection. After 24 hours the solute release decreases, which may reflect a transition to reaction with phases with slower kinetic dissolution rates (e.g. zeolites and glasses to feldspar), a decrease in available reactive surface area or precipitation. We have performed batch experiments using crushed material of the same rock to elucidate the effect of flow path
Characterization of bead trajectories through the draft tube of a turbine physical model
Energy Technology Data Exchange (ETDEWEB)
Weiland, M. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mueller, R. P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, T. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deng, Z. D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McKinstry, C. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2005-02-01
The U.S. Army Corps of Engineers (USACE) makes extensive use of 1:25 scale Plexiglass models of hydroelectric turbines along the Columbia River to study turbine hydraulic performance and to identify potential hazards for fish passing through the turbines. Plastic beads are sent through the models and imaging has been done with laser Doppler velocimetry and high-speed videography to measure flow field variables and to study the probable paths of fish through the turbine units. Understanding has been limited by the lack of data showing actual bead trajectories in three dimensions (3-D) and the lack of quantified velocity, acceleration, and other kinematics describing the trajectories of beads as they pass through the physical models.
Steel slag carbonation in a flow-through reactor system: the role of fluid-flux.
Berryman, Eleanor J; Williams-Jones, Anthony E; Migdisov, Artashes A
2015-01-01
Steel production is currently the largest industrial source of atmospheric CO2. As annual steel production continues to grow, the need for effective methods of reducing its carbon footprint increases correspondingly. The carbonation of the calcium-bearing phases in steel slag generated during basic oxygen furnace (BOF) steel production, in particular its major constituent, larnite {Ca2SiO4}, which is a structural analogue of olivine {(MgFe)2SiO4}, the main mineral subjected to natural carbonation in peridotites, offers the potential to offset some of these emissions. However, the controls on the nature and efficiency of steel slag carbonation are yet to be completely understood. Experiments were conducted exposing steel slag grains to a CO2-H2O mixture in both batch and flow-through reactors to investigate the impact of temperature, fluid flux, and reaction gradient on the dissolution and carbonation of steel slag. The results of these experiments show that dissolution and carbonation of BOF steel slag are more efficient in a flow-through reactor than in the batch reactors used in most previous studies. Moreover, they show that fluid flux needs to be optimized in addition to grain size, pressure, and temperature, in order to maximize the efficiency of carbonation. Based on these results, a two-stage reactor consisting of a high and a low fluid-flux chamber is proposed for CO2 sequestration by steel slag carbonation, allowing dissolution of the slag and precipitation of calcium carbonate to occur within a single flow-through system. Copyright © 2014. Published by Elsevier B.V.
Hyperspectral imaging flow cytometer
Sinclair, Michael B.; Jones, Howland D. T.
2017-10-25
A hyperspectral imaging flow cytometer can acquire high-resolution hyperspectral images of particles, such as biological cells, flowing through a microfluidic system. The hyperspectral imaging flow cytometer can provide detailed spatial maps of multiple emitting species, cell morphology information, and state of health. An optimized system can image about 20 cells per second. The hyperspectral imaging flow cytometer enables many thousands of cells to be characterized in a single session.
International Nuclear Information System (INIS)
Prindle, R.W.; Hopkins, P.L.
1990-10-01
The Hydrologic Code Intercomparison Project (HYDROCOIN) was formed to evaluate hydrogeologic models and computer codes and their use in performance assessment for high-level radioactive-waste repositories. This report describes the results of a study for HYDROCOIN of model sensitivity for isothermal, unsaturated flow through layered, fractured tuffs. We investigated both the types of flow behavior that dominate the performance measures and the conditions and model parameters that control flow behavior. We also examined the effect of different conceptual models and modeling approaches on our understanding of system behavior. The analyses included single- and multiple-parameter variations about base cases in one-dimensional steady and transient flow and in two-dimensional steady flow. The flow behavior is complex even for the highly simplified and constrained system modeled here. The response of the performance measures is both nonlinear and nonmonotonic. System behavior is dominated by abrupt transitions from matrix to fracture flow and by lateral diversion of flow. The observed behaviors are strongly influenced by the imposed boundary conditions and model constraints. Applied flux plays a critical role in determining the flow type but interacts strongly with the composite-conductivity curves of individual hydrologic units and with the stratigraphy. One-dimensional modeling yields conservative estimates of distributions of groundwater travel time only under very limited conditions. This study demonstrates that it is wrong to equate the shortest possible water-travel path with the fastest path from the repository to the water table. 20 refs., 234 figs., 10 tabs
Single-photon tomographic determination of regional cerebral blood flow in epilepsy
International Nuclear Information System (INIS)
Bonte, F.J.; Devous, M.D. Sr.; Stokely, E.M.; Homan, R.W.
1983-01-01
Using a single-photon emission computed tomographic scanner (SPECT) the authors determined regional cerebral blood flow (rCBF) with inhaled xenon-133, a noninvasive procedure. Studies were performed in 40 normal individuals, and these were compared with rCBF determinations in 51 patients with seizure disorders. Although positive results were obtained in 15 of 16 patients with mass lesions, the group of principal interest comprised 25 patients suffering from ''temporal lobe'' epilepsy. Only one of these had a positive x-ray computed tomogram, but 16 had positive findings on rCBF study. These findings included increased local blood flow in the ictal state and reduced flow interictally
Computer aided approximation of flow rate through systemic-pulmonary arterial shunts (SPAS).
Vennemann, Peter; Montag, Michael; Peters, Franz; Merzkirch, Wolfgang
2012-02-22
The discrimination of flow rates through bronchial arteries that are affected by pathological SPAS today still happens solely qualitatively. A reproducible quantification of flow rates, however, would enable the comprehension of phenomena like the intensified shunt perfusion seen in cases of chronic inflammations or the characterization of SPAS that may cause cardiovascular problems. A computational program is developed, that allows the modeling of individual bronchial arteries on the basis of the information provided by angiography. Angiographic images are available from the standard clinical assessment of SPAS. The flow through continuous and geometrically measurable vessel segments and SPAS is given by the law of Hagen-Poiseuille. The discharge through healthy branches is calculated by means of allometric scaling laws. The simulation results are verified by flow experiments in artificial vessel networks made of glass and PE tubing. The experimental set-up mimics realistic, pulsating pressure and flow conditions. When applied to the artificial vessel networks, the model described herein provides results for the volumetric flow rate that differ from values measured in laboratory experiments by volumetric flow through individual SPAS fairly independently from his experience and without the need of measurements additional to the mandatory angiography.
Fogel, Mark A.; Li, Christine; Elci, Okan U.; Pawlowski, Tom; Schwab, Peter J.; Wilson, Felice; Nicolson, Susan C.; Montenegro, Lisa M.; Diaz, Laura; Spray, Thomas L.; Gaynor, J William; Fuller, Stephanie; Mascio, Christopher; Keller, Marc S.; Harris, Matthew A.; Whitehead, Kevin K.; Bethel, Jim; Vossough, Arastoo; Licht, Daniel J.
2017-01-01
Background Single ventricle patients experience a high rate of brain injury and adverse neurodevelopmental outcome, however, the incidence of brain abnormalities throughout surgical reconstruction and its relationship with cerebral blood flow, oxygen delivery and carbon dioxide reactivity remains unknown. Methods Single ventricle patients were studied with MRI scans immediately prior to bidirectional Glenn (pre-BDG), prior to Fontan and then 3–9 months after Fontan reconstruction. Results One hundred and sixty eight consecutive subjects recruited into the project underwent 235 scans: 63 pre-BDG (mean age 4.8+1.7 months), 118 BDG (2.9+1.4 years) and 54 after Fontan (2.4+1.0 years). Non-acute ischemic white matter changes on T2 weighted imaging, focal tissue loss, and ventriculomegaly were all more commonly detected in BDG and Fontans compared to pre-BDG (P<0.05). BDG patients has significantly higher CBF than Fontan patients. The odds of discovering brain injury adjusting for surgical stage as well as 2 or more co-existing lesions within a patient all decreased (63–75% and 44% respectively) with increasing amount of cerebral blood flow (P<0.05). In general, there was no association of oxygen delivery (with the exception of ventriculomegaly in the BDG group) or carbon dioxide reactivity with neurological injury. Conclusion Significant brain abnormalities are commonly present in single ventricle patients and detection of these lesions increase as children progress through staged surgical reconstruction with multiple co-existing lesions more common earlier than later. In addition, this study demonstrated that BDG patients had greater CBF than Fontan patients and that there exists an inverse association of various indices of CBF with these brain lesions, however, CO2 reactivity, oxygen delivery (with one exception) were not associated with brain lesion development. PMID:28031423
International Nuclear Information System (INIS)
Lad, N; Adebayo, D; Aroussi, A
2011-01-01
Particle image velocimetry (PIV) is a successful flow mapping technique which can optically quantify large portions of a flow regime. This enables the method to be completely non-intrusive. The ability to be non-intrusive to any flow has allowed PIV to be used in a large range of industrial sectors for many applications. However, a fundamental disadvantage of the conventional PIV technique is that it cannot easily be used with flows which have no or limited optical access. Flows which have limited optical access for PIV measurement have been addressed using endoscopic PIV techniques. This system uses two separate probes which relay a light sheet and imaging optics to a planar position within the desired flow regime. This system is effective in medical and engineering applications. The present study has been involved in the development of a new endoscopic PIV system which integrates the illumination and imaging optics into one rigid probe. This paper focuses on the validation of the images taken from the novel single stem endoscopic PIV system. The probe is used within atomized spray flow and is compared with conventional PIV measurement and also pitot-static data. The endoscopic PIV system provides images which create localized velocity maps that are comparable with the global measurement of the conventional PIV system. The velocity information for both systems clearly show similar results for the spray characterization and are also validated using the pitot-static data
Realisation of low-voltage square-root-domain all-pass filters
Directory of Open Access Journals (Sweden)
Farooq A. Khanday
2013-10-01
Full Text Available Novel l ow-voltage first-order and second-order square-root-domain all-pass filters derived systematically by means of transfer function decomposition and state -space synthesis techniques are proposed. The employment of only a few geometric-mean cells and grounded capacitors permits the circuits to absorb shunt parasitic capacitances, which is desirable for production in monolithic form . The circuits enjoy the features of electronic adjustment of frequency characteristics, wider dynamic range and low-voltage environment operation. The filters are employed to design high-order all-pass filters using cascade approach. First-order low-pass and second-order band-pass filters, being the inherited building blocks of the proposed low-order all-pass filters are also discussed. The behaviour of the filters is evaluated through simulations using Taiwan semiconductor manufacturing company 0.25 μm level-3 complementary metal oxide semiconductor process parameters, where the most important performance factors are considered.
D'Sa, E. J.; Goes, J. I.; Mouw, C. B.
2016-02-01
Flow through the Aleutian Passes connects the North Pacific to the Bering Sea with the Unimak Pass forming an important conduit for the flow of Gulf of Alaska water to the southeastern Bering shelf. While the biophysical properties have been studied for this region, little is known about the dissolved organic matter (DOM) and its optically active chromophoric component (CDOM) which play key roles in ocean color and several biogeochemical and photochemical processes. Dissolved organic carbon (DOC), and CDOM absorption and fluorescence properties were measured at locations in the western Gulf of Alaska, Unimak Pass and the southeastern Bering Sea in spring 2012, a relatively cold year as indicated by hydrographic field and satellite sea surface temperature data. DOC concentrations were on average higher in the western Gulf of Alaska (112.21 ± 20.05 µM) and Unimak Pass (106.14 ± 16.10 µM), than the southeastern Bering Sea shelf (73.28 ± 11.71 µM) suggesting Gulf of Alaska shelf water to be an important source of DOM to the eastern Bering Sea. Overall, CDOM absorption was relatively low while parallel factor (PARAFAC) analysis of DOM fluorescence identified two humic-like (terrestrial and marine) and one protein-like (tryptophan-like) component in the DOM pool. Relationships between the DOM optical properties and the physical regime will be further examined in this study.
Magnetohydraulic flow through a packed bed of electrically conducting spheres
International Nuclear Information System (INIS)
Sanders, T.L.
1985-01-01
The flow of an electrically conducting fluid through a packed bed of electrically conducting spheres in the presence of a strong magnetic field constitutes a very complex flow situation due to the constant turning of the fluid in and out of magnetic field lines. The interaction of the orthogonal components of the velocity and magnetic field will induce electric fields that are orthogonal to both and the electric fields in turn can cause currents that interact with the magnetic field to generate forces against the direction of flow. The strengths of these generated forces depend primarily upon the closure paths taken by the induced currents which, in turn, depend upon the relative ratio of the electrical resistance of the solid spheres to that of the fluid. Both experimental and analytical analyses of the slow flow of a eutectic mixture of sodium and potassium (NaK) through packed cylinders containing stainless steel spheres in the presence of a strong transverse magnetic field were completed. A theory of magnetohydraulic flow is developed by analogy with the development of hydraulic radius theories of flow through porous media. An exact regional analysis is successfully applied to an infinite bed of electrically conducting spheres with a conducting or non-conducting constraining wall on one side. The equations derived are solved for many different combinations of flowrate, magnetic field strength, porosity, and electrical resistance ratio
Directory of Open Access Journals (Sweden)
Liou Tong-Miin
2005-01-01
Full Text Available The local turbulent fluid flow and heat transfer in a rotating two-pass square duct with 19 pairs of in-line 90 ∘ ribs have been investigated computationally. A Reynolds-averaged Navier-Stokes equation (RANS with a two-layer k − ϵ turbulence model was solved. The in-line 90 ∘ ribs were arranged on the leading and trailing walls with rib height-to-hydraulic diameter ratio and pitch-to-height ratio of 0.136 and 10, respectively. The Reynolds number, based on duct hydraulic diameter and bulk mean velocity, was fixed at 1.0 × 10 4 whereas the rotational number varied from 0 to 0.2 . Results are validated with previous measured velocity field and heat transfer coefficient distributions. The validation shows that the effect of rotation on the passage-averaged Nusselt number ratio can be predicted reasonably well; nevertheless, the transverse mean velocity and, in turn, the distribution of regional-averaged Nusselt number ratio are markedly underpredicted in the regions toward which the Coriolis force is directed. Further CFD studies are needed.
Simple cellular automaton model for traffic breakdown, highway capacity, and synchronized flow
Kerner, Boris S.; Klenov, Sergey L.; Schreckenberg, Michael
2011-10-01
We present a simple cellular automaton (CA) model for two-lane roads explaining the physics of traffic breakdown, highway capacity, and synchronized flow. The model consists of the rules “acceleration,” “deceleration,” “randomization,” and “motion” of the Nagel-Schreckenberg CA model as well as “overacceleration through lane changing to the faster lane,” “comparison of vehicle gap with the synchronization gap,” and “speed adaptation within the synchronization gap” of Kerner's three-phase traffic theory. We show that these few rules of the CA model can appropriately simulate fundamental empirical features of traffic breakdown and highway capacity found in traffic data measured over years in different countries, like characteristics of synchronized flow, the existence of the spontaneous and induced breakdowns at the same bottleneck, and associated probabilistic features of traffic breakdown and highway capacity. Single-vehicle data derived in model simulations show that synchronized flow first occurs and then self-maintains due to a spatiotemporal competition between speed adaptation to a slower speed of the preceding vehicle and passing of this slower vehicle. We find that the application of simple dependences of randomization probability and synchronization gap on driving situation allows us to explain the physics of moving synchronized flow patterns and the pinch effect in synchronized flow as observed in real traffic data.
Two-phase flow experiments through intergranular stress corrosion cracks
International Nuclear Information System (INIS)
Collier, R.P.; Norris, D.M.
1984-01-01
Experimental studies of critical two-phase water flow, through simulated and actual intergranular stress corrosion cracks, were performed to obtain data to evaluate a leak flow rate model and investigate acoustic transducer effectiveness in detecting and sizing leaks. The experimental program included a parametric study of the effects of crack geometry, fluid stagnation pressure and temperature, and crack surface roughness on leak flow rate. In addition, leak detection, location, and leak size estimation capabilities of several different acoustic transducers were evaluated as functions of leak rate and transducer position. This paper presents flow rate data for several different cracks and fluid conditions. It also presents the minimum flows rate detected with the acoustic sensors and a relationship between acoustic signal strength and leak flow rate
Estimation of flow rates through intergranular stress corrosion cracks
International Nuclear Information System (INIS)
Collier, R.P.; Norris, D.M.
1984-01-01
Experimental studies of critical two-phase water flow, through simulated and actual intergranular stress corrosion cracks, were performed to obtain data to evaluate a leak flow rate model and investigate acoustic transducer effectiveness in detecting and sizing leaks. The experimental program included a parametric study of the effects of crack geometry, fluid stagnation pressure and temperature, and crack surface roughness on leak flow rate. In addition, leak detection, location, and leak size estimation capabilities of several different acoustic transducers were evaluated as functions of leak rate and transducer position. This paper presents flow rate data for several different cracks and fluid conditions. It also presents the minimum flow rate detected with the acoustic sensors and a relationship between acoustic signal strength and leak flow rate
Simulation of uncompressible fluid flow through a porous media
International Nuclear Information System (INIS)
Ramirez, A.; Gonzalez, J.L.; Carrillo, F.; Lopez, S.
2009-01-01
Recently, a great interest has been focused for investigations about transport phenomena in disordered systems. One of the most treated topics is fluid flow through anisotropic materials due to the importance in many industrial processes like fluid flow in filters, membranes, walls, oil reservoirs, etc. In this work is described the formulation of a 2D mathematical model to simulate the fluid flow behavior through a porous media (PM) based on the solution of the continuity equation as a function of the Darcy's law for a percolation system; which was reproduced using computational techniques reproduced using a random distribution of the porous media properties (porosity, permeability and saturation). The model displays the filling of a partially saturated porous media with a new injected fluid showing the non-defined advance front and dispersion of fluids phenomena.