Science.gov

Sample records for commodity flow study

  1. Constellation Commodities Studies Summary

    NASA Technical Reports Server (NTRS)

    Dirschka, Eric

    2011-01-01

    Constellation program was NASA's long-term program for space exploration. The goal of the commodities studies was to solicit industry expertise in production, storage, and transportation required for future use and to improve efficiency and life cycle cost over legacy methods. Objectives were to consolidate KSC, CCAFS and other requirements; extract available industry expertise; identify commercial opportunities; and establish synergy with State of Florida partnerships. Study results are reviewed.

  2. Overview of flow studies for recycling metal commodities in the United States

    USGS Publications Warehouse

    Sibley, Scott F.

    2011-01-01

    Metal supply consists of primary material from a mining operation and secondary material, which is composed of new and old scrap. Recycling, which is the use of secondary material, can contribute significantly to metal production, sometimes accounting for more than 50 percent of raw material supply. From 2001 to 2011, U.S. Geological Survey (USGS) scientists studied 26 metals to ascertain the status and magnitude of their recycling industries. The results were published in chapters A-Z of USGS Circular 1196, entitled, "Flow Studies for Recycling Metal Commodities in the United States." These metals were aluminum (chapter W), antimony (Q), beryllium (P), cadmium (O), chromium (C), cobalt (M), columbium (niobium) (I), copper (X), germanium (V), gold (A), iron and steel (G), lead (F), magnesium (E), manganese (H), mercury (U), molybdenum (L), nickel (Z), platinum (B), selenium (T), silver (N), tantalum (J), tin (K), titanium (Y), tungsten (R), vanadium (S), and zinc (D). Each metal commodity was assigned to a single year: chapters A-M have recycling data for 1998; chapters N-R and U-W have data for 2000, and chapters S, T, and X-Z have data for 2004. This 27th chapter of Circular 1196 is called AA; it includes salient data from each study described in chapters A-Z, along with an analysis of overall trends of metals recycling in the United States during 1998 through 2004 and additional up-to-date reviews of selected metal recycling industries from 1991 through 2008. In the United States for these metals in 1998, 2000, and 2004 (each metal commodity assigned to a single year), 84 million metric tons (Mt) of old scrap was generated. Unrecovered old scrap totaled 43 Mt (about 51 percent of old scrap generated, OSG), old scrap consumed was 38 Mt (about 45 percent of OSG), and net old scrap exports were 3.3 Mt (about 4 percent of OSG). Therefore, there was significant potential for increased recovery from scrap. The total old scrap supply was 88 Mt, and the overall new

  3. Flow studies for recycling metal commodities in the United States [Chapters A-M : gold, platinum, chromium, zinc, magnesium, lead, iron, manganese, columbium (niobium), tantalum, tin, molybdenum, and cobalt

    USGS Publications Warehouse

    Sibley, Scott F., (Edited By)

    2004-01-01

    USGS Circular 1196, 'Flow Studies for Recycling Metal Commodities in the United States,' presents the results of flow studies for recycling 26 metal commodities, from aluminum to zinc. These metals are a key component of the U.S. economy. Overall, recycling accounts for more than half of the U.S. metal supply by weight and roughly 40 percent by value.

  4. Titanium recycling in the United States in 2004, chap. Y of Sibley, S.F., ed., Flow studies for recycling metal commodities in the United States

    USGS Publications Warehouse

    Goonan, Thomas G.

    2010-01-01

    As one of a series of reports that describe the recycling of metal commodities in the United States, this report discusses the titanium metal fraction of the titanium economy, which generates and uses titanium metal scrap in its operations. Data for 2004 were selected to demonstrate the titanium flows associated with these operations. This report includes a description of titanium metal supply and demand in the United States to illustrate the extent of titanium recycling and to identify recycling trends. In 2004, U.S. apparent consumption of titanium metal (contained in various titanium-bearing products) was 45,000 metric tons (t) of titanium, which was distributed as follows: 25,000 t of titanium recovered as new scrap, 9,000 t of titanium as titanium metal and titanium alloy products delivered to the U.S. titanium products reservoir, 7,000 t of titanium consumed by steelmaking and other industries, and 4,000 t of titanium contained in unwrought and wrought products exported. Titanium recycling is concentrated within the titanium metals sector of the total titanium market. The titanium market is otherwise dominated by pigment (titanium oxide) products, which generate dissipative losses instead of recyclable scrap. In 2004, scrap (predominantly new scrap) was the source of roughly 54 percent of the titanium metal content of U.S.-produced titanium metal products.

  5. 76 FR 23539 - Proposed Information Collection; Comment Request; Commodity Flow Survey

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-27

    ... Commodity Flow Survey is co-sponsored by the Bureau of Transportation Statistics, Research and Innovative Technology Administration, Department of Transportation. The survey provides data on the movement of... Census Bureau Proposed Information Collection; Comment Request; Commodity Flow Survey AGENCY: U.S....

  6. Estimation and validation of mode distances for the 1993 Commodity Flow Survey

    SciTech Connect

    Middendorf, D.P.; Bronzini, M. S.; Peterson, B.; Liu, Cheng; Chin, Shih-Miao

    1995-09-01

    The 1993 Commodity Flow Survey (CFS) collected shipment data from a sample of approximately 200,000 domestic business establishments. Each selected establishment provided information on origin, destination, commodity, shipment weight and value, and modes of transport for a sample of its outbound shipments. One data item not reported by CFS participants was shipment distance. This important piece of information was estimated by simulating probable routes using computer models of the highway, rail, air, waterway, and pipeline networks and their interconnections. This paper describes the nature of the shipment distance estimation problem, the procedures used to estimate mode-specific distances between origin and destination ZIP codes, and the techniques used to validate the results.

  7. A Study on Market Efficiency of Selected Commodity Derivatives Traded on NCDEX During 2011

    NASA Astrophysics Data System (ADS)

    Sajipriya, N.

    2012-10-01

    The study aims at testing the weak form of Efficient Market Hypothesis in the context of an emerging commodity market - National Commodity Derivatives Exchange (NCDEX), which is considered as the prime commodity derivatives market in India. The study considered daily spot and futures prices of five selected commodities traded on NCDEX over 12 month period (the futures contracts originating and expiring during the period January 2011 to December 2011) The five commodities chosen are Pepper, Crude palm Oil, steel silver and Chana as they account for almost two-thirds of the value of agricultural commodity derivatives traded on NCDEX. The results of Run test indicate that both spot and futures prices are weak form efficient

  8. We're Studying Ways to Improve Commodity Distribution to Schools.

    ERIC Educational Resources Information Center

    Cromack, Theodore; Lloyd, Nancy

    1983-01-01

    Presents procedures and findings of a Virginia Tech-conducted study-in-process of two alternatives to the United States Department of Agriculture's school lunch commodity surplus distribution program. Both alternatives--the direct cash subsidy and the commodity letter of credit--offer added flexibility to the existing system. (JBM)

  9. Substance flow analysis of parabens in Denmark complemented with a survey of presence and frequency in various commodities.

    PubMed

    Eriksson, E; Andersen, H R; Ledin, A

    2008-08-15

    Parabens are commonly used as preservatives due to anti-bactericidal and anti-fungicidal properties and they are ubiquitously present in personal care products, pharmaceuticals, food, industrial and domestic commodities. They are suspected of causing endocrine disrupting effects to aquatic organisms and adverse effects in humans and, thus, it is highly relevant to identify and quantify their sources and transportation pathways in the urban environment. Here a substance flow analysis (SFA) was performed in order to map and comprehend the substances' flow on a national basis. Many household commodities were found to contain parabens; cleaning detergents, slimy toys, and water-based paint. The presence and concentration of parabens are regulated in cosmetics and food. Use of parabens in pharmaceuticals as excipients is documented in Denmark. The import of parabens is increasing; although the number of industrial parabens containing commodities is decreasing and manufacturer reports phase-out of parabens. The vast majority of the paraben containing commodities has a durability of 18-30 months, thus the average lifetime of the paraben stock is perceived to be limited. The inflow was ca. 154 tonnes via pure chemicals and 7.2-73 tonnes via commodities in 2004. This corresponds to an average wastewater concentration of 640-900 microg/L, when excluding discharge to solid waste, soil, biodegradation and metabolism. This is in the same order of magnitudes as can be found in industrial wastewater but higher than that seen in domestic wastewater. The data needed for the SFA is sparse, dispersed, and difficult to access and associated with a great deal of uncertainty. PMID:18243542

  10. (Alaskan commodities irradiation project: An options analysis study)

    SciTech Connect

    Zarling, J.P.; Swanson, R.B.; Logan, R.R.; Das, D.K.; Lewis, C.E.; Workman, W.G.; Tumeo, M.A.; Hok, C.I.; Birklind, C.A.; Bennett, F.L. . Inst. of Northern Engineering)

    1989-09-01

    The ninety-ninth US Congress commissioned a six-state food irradiation research and development program to evaluate the commercial potential of this technology. Hawaii, Washington, Iowa, Oklahoma and Florida as well as Alaska have participated in the national program; various food products including fishery products, red meats, tropical and citrus fruits and vegetables have been studied. The purpose of the Alaskan study was to review and evaluate those factors related to the technical and economic feasibility of an irradiator in Alaska. This options analysis study will serve as a basis for determining the state's further involvement in the development of food irradiation technology.

  11. Delay discounting of different commodities.

    PubMed

    Weatherly, Jeffrey N; Terrell, Heather K; Derenne, Adam

    2010-01-01

    When outcomes are delayed, their value is decreased. Delay discounting is a much-studied topic because it is correlated with certain disorders (e.g., pathological gambling). The present study attempts to determine how people would delay discount a number of different commodities, ranging from money to dating partners to federal education legislation. Participants completed delay discounting tasks pertaining to 5 different commodities, with a different set of 5 commodities for 2 groups. Results showed that different commodities were often discounted differently. Both data sets were also subjected to factor analysis. A 2-factor solution was found for both, suggesting that there are multiple "domains" of commodities. This finding is of interest because it suggests that measuring delay discounting for one commodity within a particular domain of commodities will be predictive of how people discount other commodities within that domain but will not be predictive of how they discount commodities within another domain. PMID:20718227

  12. Commodities Oddities.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1995-01-01

    Officials at the U.S. Department of Agriculture (USDA) have been offering schools more fresh fruits and vegetables through the commodities program. Despite problems in delivering perishable food in good condition, food directors are supporting the program. However, two new free-trade agreements and the Republican-led Congress may change the…

  13. An efficient and robust design optimisation of multi-state flow network for multiple commodities using generalised reliability evaluation algorithm and edge reduction method

    NASA Astrophysics Data System (ADS)

    Chou, Yu-Cheng; Lin, Po Ting

    2015-10-01

    The network of delivering commodities has been an important design problem in our daily lives and many transportation applications. The reliability of delivering commodities from a source node to a sink node in the network is maximised to find the optimal routing. However, the design problem is not simple due to randomly distributed attributes in each path, multiple commodities with variable path capacities and the allowable time constraints for delivery. This paper presents the design optimisation of the multi-state flow network (MSFN) for multiple commodities. We propose an efficient and robust approach to evaluate the system reliability in the MSFN with respect to randomly distributed path attributes and to find the optimal routing subject to the allowable time constraints. The delivery rates of the path segments are evaluated and the minimal-speed arcs are eliminated to reduce the complexity of the MSFN. Accordingly, the correct optimal routing is found and the worst-case reliability is evaluated. The reliability of the optimal routing is at least higher than worst-case measure. Three benchmark examples are utilised to demonstrate the proposed method. The comparisons between the original and the reduced networks show that the proposed method is very efficient.

  14. Towards more spatially explicit assessments of virtual water flows: linking local water use and scarcity to global demand of Brazilian farming commodities

    NASA Astrophysics Data System (ADS)

    Flach, Rafaela; Ran, Ylva; Godar, Javier; Karlberg, Louise; Suavet, Clement

    2016-07-01

    Global consumption of farming commodities is an important driver of water demand in regions of production. This is the case in Brazil, which has emerged as one of the main producers of globally traded farming commodities. Traditional methods to assess environmental implications of this demand rely on international trade material flows at country resolution; we argue for the need of finer scales that capture spatial heterogeneity in environmental variables in the regions of production, and that account for differential sourcing within the borders of a country of production. To illustrate this, we obtain virtual water flows from Brazilian municipalities to countries of consumption, by allocating high-resolution water footprints of sugarcane and soy production to spatially-explicit material trade flows. We found that this approach results in differences of virtual water use estimations of over 20% when compared to approaches that disregard spatial heterogeneity in sourcing patterns, for three of the main consumers of the analysed crops. This discrepancy against methods using national resolution in trade flows is determined by national heterogeneity in water resources, and differential sourcing. To illustrate the practical implications of this approach, we relate virtual water flows to water stress, identifying where global demand for water coincides with high levels of water stress. For instance, the virtual water flows for Brazilian sugarcane sourced by China were disproportionally less associated to areas with higher water stress when compared to those of the EU, due to EU’s much higher reliance on sugarcane from water scarce areas in Northeast Brazil. Our findings indicate that the policy relevance of current assessments of virtual water flows that rely on trade data aggregated at the national level may be hampered, as they do not capture the spatial heterogeneity in water resources, water use and water management options.

  15. Historical statistics for mineral and material commodities in the United States

    USGS Publications Warehouse

    Kelly, Thomas; Matos, Grecia; with Buckingham, David; DiFrancesco, Carl; Porter, Kenneth; Berry, Cyrus; Crane, Melissa; Goonan, Thomas; Sznopek, John

    2005-01-01

    The USGS makes this information available through published products, including monthly, quarterly, and annual Mineral Industry Surveys, the annual Minerals Yearbook (MYB), the annual Mineral Commodity Summaries (MCS), and special mineral commodity studies, including the history of metal prices and materials flow studies

  16. Commodity-Free Calibration

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Commodity-free calibration is a reaction rate calibration technique that does not require the addition of any commodities. This technique is a specific form of the reaction rate technique, where all of the necessary reactants, other than the sample being analyzed, are either inherent in the analyzing system or specifically added or provided to the system for a reason other than calibration. After introduction, the component of interest is exposed to other reactants or flow paths already present in the system. The instrument detector records one of the following to determine the rate of reaction: the increase in the response of the reaction product, a decrease in the signal of the analyte response, or a decrease in the signal from the inherent reactant. With this data, the initial concentration of the analyte is calculated. This type of system can analyze and calibrate simultaneously, reduce the risk of false positives and exposure to toxic vapors, and improve accuracy. Moreover, having an excess of the reactant already present in the system eliminates the need to add commodities, which further reduces cost, logistic problems, and potential contamination. Also, the calculations involved can be simplified by comparison to those of the reaction rate technique. We conducted tests with hypergols as an initial investigation into the feasiblility of the technique.

  17. Bypass Flow Study

    SciTech Connect

    Richard Schultz

    2011-09-01

    The purpose of the fluid dynamics experiments in the MIR (Matched Index of-Refraction) flow system at Idaho National Laboratory (INL) is to develop benchmark databases for the assessment of Computational Fluid Dynamics (CFD) solutions of the momentum equations, scalar mixing, and turbulence models for the flow ratios between coolant channels and bypass gaps in the interstitial regions of typical prismatic standard fuel element (SFE) or upper reflector block geometries of typical Modular High-temperature Gas-cooled Reactors (MHTGR) in the limiting case of negligible buoyancy and constant fluid properties. The experiments use Particle Image Velocimetry (PIV) to measure the velocity fields that will populate the bypass flow study database.

  18. Micromodel foam flow study

    SciTech Connect

    Chambers, K.T.; Radke, C.J.

    1990-10-01

    Foams are often utilized as part of enhanced oil recovery techniques. This report presents the results of a micromodel foam flow study. Micromodels are valuable tools in uncovering capillary phenomena responsible for lamellae generation and coalescence during foam flow in porous media. Among the mechanisms observed are snap-off, weeping-flow breakup, and lamella division and leave behind. Coalescence mechanisms include dynamic capillary-pressure-induced lamella drainage and gas diffusion. These phenomena are sensitive to the mode of injection, the local capillary environment, and the geometry of the pore structure. An important consideration in presenting a tractable model of foam flow behavior is the ability to identify the pore-level mechanisms having the greatest impact on foam texture. The predominant mechanisms will vary depending upon the application for foam as an enhanced oil recovery (EOR) fluid. Both simultaneous gas and surfactant injection and surfactant alternating with gas injection (SAG) have been used to create foam for mobility control in EOR projects. The model developed is based on simultaneous gas and surfactant injection during steady-state conditions into a Berea sandstone core. The lamellae generation and coalescence mechanisms included in this model are snap-off, lamella division, and dynamic capillary-pressure-induced lamella drainage. This simplified steady-state model serves as a foundation for developing more complete rate expressions and for extending the population balance to handle transient foam flow behavior. 70 refs., 30 figs.

  19. Broilers, Beans, and Bellies: Teaching Commodity Futures.

    ERIC Educational Resources Information Center

    Dunham, Loren J.

    1983-01-01

    People should understand what the commodity futures market is and who uses it. The commodity futures market should be studied in a high school economics course so a one-week unit was developed for students that involved them in a simulation as hedgers and speculators. (AM)

  20. TV News Flow Studies Revisited.

    ERIC Educational Resources Information Center

    Hjarvard, Stig

    1995-01-01

    Compares different theoretical approaches to the study of international news. Finds many comparative studies of the foreign news output of national broadcasters and few studies analyzing the actual flow of television news between actors at the wholesale level and the flow between wholesale and retail level. Suggests a better framework for the…

  1. An empirical performance analysis of commodity memories in commodity servers

    SciTech Connect

    Kerbyson, D. J.; Lang, M. K.; Patino, G.

    2004-01-01

    This work details a performance study of six different commodity memories in two commodity server nodes on a number of microbenchmarks, that measure low-level performance characteristics, as well as on two applications representative of the ASCI workload. Thc memories vary both in terms of performance, including latency and bandwidths, and also in terms of their physical properties and manufacturer. Two server nodes were used; one Itanium-II Madison based system, and one Xeon based system. All the memories examined can be used within both processing nodes. This allows the performance of the memories to be directly examined while keeping all other factors within a processing node the same (processor, motherboard, operating system etc.). The results of this study show that there can be a significant difference in application performance from the different memories - by as much as 20%. Thus, by choosing the most appropriate memory for a processing node at a minimal cost differential, significant improved performance may be achievable.

  2. Basic studies of baroclinic flows

    NASA Technical Reports Server (NTRS)

    Miller, Tim L.; Chou, S.-H.; Leslie, Fred W.; Lu, H.-I.; Butler, K. A.

    1991-01-01

    Computations were completed of transition curves in the conventional annulus, including hysteresis effect. The model GEOSIM was used to compute the transition between axisymmetric flow and baroclinic wave flow in the conventional annulus experiments. Thorough testing and documentation of the GEOSIM code were also completed. The Spacelab 3 results from the Geophysical Fluid Flow Cell (GFFC) were reviewed and numerical modeling was performed of many of the cases with horizontal temperature gradients as well as heating from below, with different rates of rotation. A numerical study of the lower transition to axisymmetric flow in the baroclinic annulus was performed using GEOSIM.

  3. Mineral Commodity Summaries 2011

    USGS Publications Warehouse

    U.S. Geological Survey

    2011-01-01

    Each chapter of the 2011 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2010 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses. For mineral commodities for which there is a Government stockpile, detailed information concerning the stockpile status is included in the two-page synopsis. Mineral Commodity Summaries 2011 contains new chapters on iron oxide pigments, wollastonite, and zeolites. The chapters on mica (natural), scrap and flake and mica (natural), sheet have been combined into a single chapter - mica (natural). Abbreviations and units of measure, and definitions of selected terms used in the report, are in Appendix A and Appendix B, respectively. "Appendix C - Reserves and Resources" has been divided into "Part A - Resource/Reserve Classification for Minerals" and "Part B - Sources of Reserves Data," including some information that was previously in this introduction. A directory of USGS minerals information country specialists and their responsibilities is Appendix D. The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the MCS 2011 are welcomed.

  4. Equity in Whom Gets Studied: A Systematic Review Examining Geographical Region, Gender, Commodity, and Employment Context in Research of Low Back Disorders in Farmers.

    PubMed

    Trask, Catherine; Khan, Muhammad Idress; Adebayo, Olugbenga; Boden, Catherine; Bath, Brenna

    2015-01-01

    Farmers are at high risk of having low back disorders (LBDs). Agriculture employs half the global workforce, but it is unclear whether all farming populations are represented equitably in the LBD literature. This systematic review quantifies the number and quality of research studies by geographical region, agricultural commodity, and farmer characteristics. MEDLINE, Web of Science, CINAHL, Scopus, and Embase databases were searched using conceptual groups of search terms: "farming" and "LBD." Screening and extraction were performed by two researchers in parallel, then reconciled through discussion. Extracted study characteristics included location of study; commodity produced; worker sex, ethnicity, and migration status; type of employment; and study quality. These were compared with agricultural employment statistics from the International Labour Organization and World Bank. From 125 articles, roughly half (67) did not specify the employment context of the participants in terms of migration status or subsistence versus commercial farming. Although in many regions worldwide women make up the bulk of the workforce, only a minority of low back disorder studies focus on women. Despite the predominance of the agricultural workforce in developing nations, 91% of included studies were conducted in developed nations. There was no significant difference in study quality by geographic region. The nature of the world's agricultural workforce is poorly represented by the literature when it comes to LBD research. If developing nations, female sex, and migrant work are related to increased vulnerability, then these groups need more representation to achieve equitable occupational health study. PMID:26237717

  5. Mineral commodity summaries 2013

    USGS Publications Warehouse

    U.S. Geological Survey

    2013-01-01

    Each chapter of the 2013 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2012 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses. For mineral commodities for which there is a Government stockpile, detailed information concerning the stockpile status is included in the two-page synopsis. Abbreviations and units of measure, and definitions of selected terms used in the report, are in Appendix A and Appendix B, respectively. “Appendix C—Reserves and Resources” includes “Part A—Resource/Reserve Classification for Minerals” and “Part B—Sources of Reserves Data.” A directory of USGS minerals information country specialists and their responsibilities is Appendix D. The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the MCS 2013 are welcomed.

  6. Mineral commodity summaries 2014

    USGS Publications Warehouse

    U.S. Geological Survey

    2014-01-01

    Each chapter of the 2014 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2013 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses. For mineral commodities for which there is a Government stockpile, detailed information concerning the stockpile status is included in the two-page synopsis. Abbreviations and units of measure, and definitions of selected terms used in the report, are in Appendix A and Appendix B, respectively. “Appendix C—Reserves and Resources” includes “Part A—Resource/Reserve Classification for Minerals” and “Part B—Sources of Reserves Data.” A directory of USGS minerals information country specialists and their responsibilities is Appendix D. The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the MCS 2014 are welcomed.

  7. DNS studies of bubbly flows

    NASA Astrophysics Data System (ADS)

    Tryggvason, Gretar; Esmaeeli, Asghar; Biswas, Souvik

    2004-11-01

    Recent stuies of bubbly flows, using direct numerical simulations, are discussed. The goal of this study is to examine the collective behavior of many bubbles as the rise Reynolds number is increased and and a single bubble rises unsteadily, as well as to examine the motion of bubbles in channels. A front-tracking/finite volume method is used to fully resolve all flow scales, including the bubbles and the flow around them. Two cases are simulated, for one the bubbles remain nearly spherical and for the other case the bubbles are deformable and wobble. The wobbly bubbles remains relatively uniformly distributed and are not susceptible to the streaming instability found by Bunner and Tryggvason (2003) for deformable bubbles at lower rise Reynolds numbers. The more spherical bubbles, on the other hand, form transients ``rafts'' somewhat similar to those seen in potential flow simulation of many bubbles. For channel flow we compare results from direct numerical simulations of bubbly flow with prediction of the steady-state two-fluid model of Antal, Lahey, and Flaherty (1991). The simulations are done assuming a two-dimensional system and the model coefficients are adjusted slightly to match the data for upflow. The results generally agree reasonably well, even though the simulated void fraction is considerably higher than the one assumed in the derivation of the model. Research supported by DOE.

  8. Bleed Hole Flow Phenomena Studied

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Boundary-layer bleed is an invaluable tool for controlling the airflow in supersonic aircraft engine inlets. Incoming air is decelerated to subsonic speeds prior to entering the compressor via a series of oblique shocks. The low momentum flow in the boundary layer interacts with these shocks, growing in thickness and, under some conditions, leading to flow separation. To remedy this, bleed holes are strategically located to remove mass from the boundary layer, reducing its thickness and helping to maintain uniform flow to the compressor. The bleed requirements for any inlet design are unique and must be validated by extensive wind tunnel testing to optimize performance and efficiency. To accelerate this process and reduce cost, researchers at the NASA Lewis Research Center initiated an experimental program to study the flow phenomena associated with bleed holes. Knowledge of these flow properties will be incorporated into computational fluid dynamics (CFD) models that will aid engine inlet designers in optimizing bleed configurations before any hardware is fabricated. This ongoing investigation is currently examining two hole geometries, 90 and 20 (both with 5-mm diameters), and various flow features.

  9. Kinetic market models with single commodity having price fluctuations

    NASA Astrophysics Data System (ADS)

    Chatterjee, A.; Chakrabarti, B. K.

    2006-12-01

    We study here numerically the behavior of an ideal gas like model of markets having only one non-consumable commodity. We investigate the behavior of the steady-state distributions of money, commodity and total wealth, as the dynamics of trading or exchange of money and commodity proceeds, with local (in time) fluctuations in the price of the commodity. These distributions are studied in markets with agents having uniform and random saving factors. The self-organizing features in money distribution are similar to the cases without any commodity (or with consumable commodities), while the commodity distribution shows an exponential decay. The wealth distribution shows interesting behavior: gamma like distribution for uniform saving propensity and has the same power-law tail, as that of the money distribution, for a market with agents having random saving propensity.

  10. Debris flow study in Malaysia

    NASA Astrophysics Data System (ADS)

    Bahrin Jaafar, Kamal

    2016-04-01

    The phenomenon of debris flow occurs in Malaysia occasionally. The topography of Peningsular Malysia is characterized by the central mountain ranges running from south to north. Several parts of hilly areas with steep slopes, combined with high saturation of soil strata that deliberately increase the pore water pressure underneath the hill slope. As a tropical country Malaysia has very high intensity rainfall which is triggered the landslide. In the study area where the debris flow are bound to occur, there are a few factors that contribute to this phenomenon such as high rainfall intensity, very steep slope which an inclination more than 35 degree and sandy clay soil type which is easily change to liquidity soil. This paper will discuss the study of rainfall, mechanism, modeling and design of mitigation measure to avoid repeated failure in future in same area.

  11. Swan falls instream flow study

    SciTech Connect

    Anglin, D.R.; Cummings, T.R.; Ecklund, A.E.

    1992-10-01

    The purpose of the Swan Falls Instream Flow Study was to define the relationship between streamflows and instream habitat for resident fish species and to assess the relative impact of several different hydrographs on resident fish habitat. Specific objectives included the following: (1) Conduct a literature search to compile life history, distribution, and habitat requirements for species of interest. Physical and hydrologic characteristics of the Snake River were also compiled. (2) Determine physical habitat versus discharge relationships and conduct habitat time series analysis for each species/lifestage using the Instream Flow Incremental Methodology (IFIM) developed by the U.S. Fish and Wildlife Service. (3) Examine the impacts on resident fish habitat of proposed hydrographs, including Swan Falls Agreement flows, relative to current conditions. (4) Characterize water quality conditions, including water temperature and dissolved oxygen, in the vicinity of the study area and determine the implications of those conditions for the resident species of interest. (5) Determine streamflows necessary to protect and maintain resident fish habitat in the study area.

  12. Mineral commodity profiles: Silver

    USGS Publications Warehouse

    Butterman, W.C.; Hilliard, Henry E.

    2005-01-01

    United States, about 30 companies accounted for more than 90 percent of the silver fabricated. The consumption of silver for all fabrication uses is expected to grow slowly through the decade ending in 2010 at about 1.3 percent per year for the world and 2.4 percent per year for the United States. World and U.S. reserves and reserve bases are more than adequate to satisfy the demand for newly mined silver through 2010. The other components of supply will be silver recovered from scrap, silver from industrial stocks, and silver bullion that is sold into the market from commodity exchange and private stocks.

  13. Studies of two phase flow

    NASA Technical Reports Server (NTRS)

    Witte, Larry C.

    1994-01-01

    The development of instrumentation for the support of research in two-phase flow in simulated microgravity conditions was performed. The funds were expended in the development of a technique for characterizing the motion and size distribution of small liquid droplets dispersed in a flowing gas. Phenomena like this occur in both microgravity and normal earth gravity situations inside of conduits that are carrying liquid-vapor mixtures at high flow rates. Some effort to develop a conductance probe for the measurement of liquid film thickness was also expended.

  14. Online Learner's "Flow" Experience: An Empirical Study

    ERIC Educational Resources Information Center

    Shin, Namin

    2006-01-01

    This study is concerned with online learners' "low" experiences. On the basis of Csikszentmihalyi's theory of flow, flow was conceptualised as a complex, multimentional, reflective construct composing of "enjoyment", "telepresence", "focused attention", "engagement" and "time distortion" on the part of learners. A flow model was put forward with…

  15. Multinetwork of international trade: A commodity-specific analysis

    NASA Astrophysics Data System (ADS)

    Barigozzi, Matteo; Fagiolo, Giorgio; Garlaschelli, Diego

    2010-04-01

    We study the topological properties of the multinetwork of commodity-specific trade relations among world countries over the 1992-2003 period, comparing them with those of the aggregate-trade network, known in the literature as the international-trade network (ITN). We show that link-weight distributions of commodity-specific networks are extremely heterogeneous and (quasi) log normality of aggregate link-weight distribution is generated as a sheer outcome of aggregation. Commodity-specific networks also display average connectivity, clustering, and centrality levels very different from their aggregate counterpart. We also find that ITN complete connectivity is mainly achieved through the presence of many weak links that keep commodity-specific networks together and that the correlation structure existing between topological statistics within each single network is fairly robust and mimics that of the aggregate network. Finally, we employ cross-commodity correlations between link weights to build hierarchies of commodities. Our results suggest that on the top of a relatively time-invariant “intrinsic” taxonomy (based on inherent between-commodity similarities), the roles played by different commodities in the ITN have become more and more dissimilar, possibly as the result of an increased trade specialization. Our approach is general and can be used to characterize any multinetwork emerging as a nontrivial aggregation of several interdependent layers.

  16. 48 CFR 8.715 - Replacement commodities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Replacement commodities. 8... Are Blind or Severely Disabled 8.715 Replacement commodities. When a commodity on the Procurement List is replaced by another commodity which has not been previously acquired, and a qualified...

  17. Hybrid laminar flow control study

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Hybrid laminar flow control (HLFC) in which leading edge suction is used in conjunction with wing pressure distribution tailoring to postpone boundary layer transition and reduce friction drag was examined. Airfoil design characteristics required for laminar flow control (LFC) were determined. The aerodynamic design of the HLFC wing for a 178 passenger commercial turbofan transport was developed, and a drag was estimated. Systems changes required to install HLFC were defined, and weights and fuel economy were estimated. The potential for 9% fuel reduction for a 3926-km (2120-nmi) mission is identified.

  18. 76 FR 77670 - Retail Commodity Transactions Under Commodity Exchange Act

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... FR 39188 (Sept. 25, 1990) (``Brent Interpretation''). II. Commission Interpretation of ``Actual... ``actual delivery'' as set forth in section 2(c)(2)(D)(ii)(III)(aa) of the Commodity Exchange Act (``CEA... application. In particular, new CEA section 2(c)(2)(D)(ii)(III)(aa) \\18\\ excepts a contract of sale...

  19. 78 FR 52426 - Retail Commodity Transactions Under Commodity Exchange Act

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ... Transactions Under Commodity Exchange Act, 76 FR 77670 (Dec. 14, 2011). II. Summary of Comments A. Comments... factors set forth in the Interpretation. \\19\\ 76 FR 77670, 77672 (Dec. 14, 2011). \\20\\ Id. 2. When the 28...)(ii). \\24\\ See, e.g., Statutory Interpretation Concerning Forward Transactions, 55 FR 39188 (Sept....

  20. FlowSim/FlowRisk: A code system for studying risk associated with material process flows

    SciTech Connect

    Kaufman, A.M.

    1993-10-01

    The need to study and assess life-cycle risks of Pu release by nuclear warheads during peace time lead to the development of a code suite which could model day to day operations involving nuclear weapons and calculate the associated risk involved in these proceedings. The life-cycle study called LIONSHARE is described in Reference 1. The code that models the flow is called FlowSim. The code that evaluates the associated risk is called FlowRisk. We shall concentrate here on the methodology used by FlowSim in modeling material flows. FlowRisk, mainly a postprocessor of FlowSim runs, will be dealt with in less detail.

  1. Alaskan Commodities Irradiation Project

    SciTech Connect

    Zarling, J.P.; Swanson, R.B.; Logan, R.R.; Das, D.K.; Lewis, C.E.; Workman, W.G.; Tumeo, M.A.; Hok, C.I.; Birklid, C.A.; Bennett, F.L.

    1988-12-01

    The ninety-ninth US Congress commissioned a six-state food irradiation research and development program to evaluate the commercial potential of this technology. Hawaii, Washington, Iowa, Oklahoma and Florida as well as Alaska have participated in the national program; various food products including fishery products, red meats, tropical and citrus fruits and vegetables have been studied. The purpose of the Alaskan study was to review and evaluate those factors related to the technical and economic feasibility of an irradiator in Alaska. This options analysis study will serve as a basis for determining the state's further involvement in the development of food irradiation technology. 40 refs., 50 figs., 53 tabs.

  2. 77 FR 25319 - Commodity Options

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    ... Recordkeeping, 76 FR 29818, May 23, 2011 (``Product Definitions NPRM''). The final rule and interpretations that... not applicable. \\7\\ Commodity Options and Agricultural Swaps, 76 FR 6095, Feb. 3, 2011. Note that in... 10, 2011 and are not addressed herein. See Agricultural Swaps, 76 FR 49291, Aug. 10, 2011...

  3. Aflatoxins in selected Thai commodities.

    PubMed

    Tansakul, Natthasit; Limsuwan, Sasithorn; Böhm, Josef; Hollmann, Manfred; Razzazi-Fazeli, Ebrahim

    2013-01-01

    Aflatoxin (AF) B1, B2, G1 and G2 were determined in 120 samples of selected Thai commodities including unpolished rice, unpolished glutinous rice, chilli powder, whole dried chilli pods and raw peanut. The mean concentrations of the total AFs for analysed samples were 0.16, 25.43, 14.18, 6.62 and 1.43 µg kg(-1) with positive incidences of 4%, 20%, 97%, 37% and 30%, respectively. Quantitative analysis was performed using HPLC equipped with post-column derivatisation and fluorescence detection. Sample clean-up was carried out using immunoaffinity columns for selective enrichment of AFs. The method was validated by using certified reference material, which showed recoveries over 85%. The limit of detections (LODs) and limit of quantifications (LOQs) were in a range between 0.01-0.11 µg kg(-1) and 0.03-0.38 µg kg(-1), respectively. The results clearly demonstrated that AFs were detectable in different matrices. Chilli powder was found to have the highest level of AFs contamination followed by chilli pods, peanut and rice, respectively. However, among the selected commodities, unpolished rice contained only trace levels of AFB1 and AFB2. With regard to the fact that AFs are a natural contaminant in commodities, this report calls to attention the regular monitoring and effective control of food commodities to prevent health hazards. PMID:24779933

  4. Aflatoxin contamination in food commodities in Bangladesh.

    PubMed

    Roy, Monika; Harris, Julie; Afreen, Sadia; Deak, Eszter; Gade, Lalitha; Balajee, S Arunmozhi; Park, Benjamin; Chiller, Tom; Luby, Stephen

    2013-01-01

    During September 2009, we performed a rapid cross-sectional study to investigate the extent of aflatoxin contamination among common Bangladeshi foods. We collected eight common human food commodities (rice, lentils, wheat flour, dates, betelnut, red chili powder, ginger and groundnuts) and poultry feed samples from two large markets in each of three cities in Bangladesh. We quantified aflatoxin levels from pooled subsamples using fluorescence high-performance liquid chromatography. Aflatoxin levels were highest in dates and groundnuts (maximum 623 and 423 ng/g), respectively. Samples of betelnut (mean 30.6 ng/g), lentils (mean 21.2 ng/g) and red chili powder (>20 ng/g) also had elevated levels. The mean aflatoxin level among poultry feed samples was 73.0 ng/g. Aflatoxin levels were above the US maximum regulatory levels of 20 ng/g in five of eight commonly ingested human food commodities tested. PMID:24786620

  5. Multiple pathways of commodity crop expansion in tropical forest landscapes

    NASA Astrophysics Data System (ADS)

    Meyfroidt, Patrick; Carlson, Kimberly M.; Fagan, Matthew E.; Gutiérrez-Vélez, Victor H.; Macedo, Marcia N.; Curran, Lisa M.; DeFries, Ruth S.; Dyer, George A.; Gibbs, Holly K.; Lambin, Eric F.; Morton, Douglas C.; Robiglio, Valentina

    2014-07-01

    Commodity crop expansion, for both global and domestic urban markets, follows multiple land change pathways entailing direct and indirect deforestation, and results in various social and environmental impacts. Here we compare six published case studies of rapid commodity crop expansion within forested tropical regions. Across cases, between 1.7% and 89.5% of new commodity cropland was sourced from forestlands. Four main factors controlled pathways of commodity crop expansion: (i) the availability of suitable forestland, which is determined by forest area, agroecological or accessibility constraints, and land use policies, (ii) economic and technical characteristics of agricultural systems, (iii) differences in constraints and strategies between small-scale and large-scale actors, and (iv) variable costs and benefits of forest clearing. When remaining forests were unsuitable for agriculture and/or policies restricted forest encroachment, a larger share of commodity crop expansion occurred by conversion of existing agricultural lands, and land use displacement was smaller. Expansion strategies of large-scale actors emerge from context-specific balances between the search for suitable lands; transaction costs or conflicts associated with expanding into forests or other state-owned lands versus smallholder lands; net benefits of forest clearing; and greater access to infrastructure in already-cleared lands. We propose five hypotheses to be tested in further studies: (i) land availability mediates expansion pathways and the likelihood that land use is displaced to distant, rather than to local places; (ii) use of already-cleared lands is favored when commodity crops require access to infrastructure; (iii) in proportion to total agricultural expansion, large-scale actors generate more clearing of mature forests than smallholders; (iv) property rights and land tenure security influence the actors participating in commodity crop expansion, the form of land use displacement

  6. Navier-Stokes Computations on Commodity Computers

    NASA Technical Reports Server (NTRS)

    Vatsa, Veer N.; Faulkner, Thomas R.

    1998-01-01

    In this paper we discuss and demonstrate the feasibility of solving high-fidelity, nonlinear computational fluid dynamics (CFD) problems of practical interest on commodity machines, namely Pentium Pro PC's. Such calculations have now become possible due to the progress in computational power and memory of the off-the-shelf commodity computers, along with the growth in bandwidth and communication speeds of networks. A widely used CFD code known as TLNS3D, which was developed originally on large shared memory computers was selected for this effort. This code has recently been ported to massively parallel processor (MPP) type machines, where natural partitioning along grid blocks is adopted in which one or more blocks are distributed to each of the available processors. In this paper, a similar approach is adapted to port this code to a cluster of Pentium Pro computers. The message passing among the processors is accomplished through the use of standard message passing interface (MPI) libraries. Scaling studies indicate fairly high level of parallelism on such clusters of commodity machines, thus making solutions to Navier-Stokes equations for practical problems more affordable.

  7. Figuring Home: The Role of Commodities in the Transnational Experience

    ERIC Educational Resources Information Center

    Penman, Christine; Omar, Maktoba

    2011-01-01

    This article proposes to investigate the role played by material goods in the transnational experience. Previous research has shown that the movement of people across the world comes with a corollary of cultural flows which find their expression in multiple ways. This article looks more specifically at the kind of commodities that international…

  8. Is women's labor a commodity?

    PubMed

    Anderson, Elizabeth S

    1990-01-01

    ...A commercial surrogate mother is anyone who is paid money to bear a child for other people and terminate her parental rights, so that the others may raise the child as exclusively their own. The growth of commercial surrogacy has raised with new urgency a class of concerns regarding the proper scope of the market. Some critics have objected to commercial surrogacy on the ground that it improperly treats children and women's reproductive capacities as commodities. The prospect of reducing children to consumer durables and women to baby factories surely inspires revulsion. But are there good reasons behind the revulsion? And is this an accurate description of what commercial surrogacy implies? This article offers a theory about what things are properly regarded as commodities which supports the claim that commercial surrogacy constitutes an unconscionable commodification of children and of women's reproductive capacities. PMID:11651966

  9. Numerical study of flow turning phenomenon

    NASA Astrophysics Data System (ADS)

    Baum, J. D.; Levine, J. N.

    1986-01-01

    A research project is currently being conducted that is to provide an understanding of the physical mechanisms by which energy is exchanged between the mean and acoustic flowfields in resonant combustion chambers, giving particular attention to solid rocket motors. The present paper is concerned with progress which has been made toward the understanding of the 'flow turning' phenomenon. This term is used to describe the loss of acoustic energy by the acoustic field in the combustor resulting from the inflow of combustion products through the lateral boundary of a combustion chamber containing longitudinal acoustic waves. Attention is given to the modeling of flow turning, acoustic refraction, the numerical solution, numerical results, acoustic wave propagation with no mean flow, and a flow turning study. The discussed research verifies the existence of the flow turning loss phenomenon.

  10. 49 CFR 173.167 - Consumer commodities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Consumer commodities. 173.167 Section 173.167... Consumer commodities. (a) Effective January 1, 2013, a “consumer commodity” (see § 171.8 of this subchapter... kPa) prescribed in § 173.27(c) of this part. Consumer commodities are excepted from...

  11. 49 CFR 173.167 - Consumer commodities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Consumer commodities. 173.167 Section 173.167... Consumer commodities. (a) Effective January 1, 2013, a “consumer commodity” (see § 171.8 of this subchapter... kPa) prescribed in § 173.27(c) of this part. Consumer commodities are excepted from...

  12. 22 CFR 228.51 - Commodities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Commodities. 228.51 Section 228.51 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES ON SOURCE, ORIGIN AND NATIONALITY FOR COMMODITIES AND SERVICES FINANCED BY USAID Waivers § 228.51 Commodities. (a) Waiver criteria. Any waiver must be based upon one of the criteria listed in...

  13. 22 CFR 228.51 - Commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Commodities. 228.51 Section 228.51 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES ON SOURCE, ORIGIN AND NATIONALITY FOR COMMODITIES AND... agricultural commodities, motor vehicles, or pharmaceuticals (see § 228.13, “Special source rules...

  14. 22 CFR 120.4 - Commodity jurisdiction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Commodity jurisdiction. 120.4 Section 120.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.4 Commodity jurisdiction. (a) The commodity jurisdiction procedure is used with the U.S. Government if doubt exists as to whether an article...

  15. 7 CFR 1405.9 - Commodity assessments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Commodity assessments. 1405.9 Section 1405.9 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Commodity assessments. (a) CCC will deduct from the proceeds of a marketing assistance loan an amount...

  16. 22 CFR 120.4 - Commodity jurisdiction.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Commodity jurisdiction. 120.4 Section 120.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.4 Commodity jurisdiction. (a) The commodity jurisdiction procedure is used with the...

  17. 22 CFR 120.4 - Commodity jurisdiction.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Commodity jurisdiction. 120.4 Section 120.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.4 Commodity jurisdiction. (a) The commodity jurisdiction procedure is used with the...

  18. 22 CFR 120.4 - Commodity jurisdiction.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Commodity jurisdiction. 120.4 Section 120.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.4 Commodity jurisdiction. (a) The commodity jurisdiction procedure is used with the...

  19. 7 CFR 1401.4 - Commodity certificates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Commodity certificates. 1401.4 Section 1401.4 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES COMMODITY CERTIFICATES, IN KIND PAYMENTS, AND OTHER FORMS OF PAYMENT § 1401.4...

  20. 22 CFR 120.4 - Commodity jurisdiction.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Commodity jurisdiction. 120.4 Section 120.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.4 Commodity jurisdiction. (a) The commodity jurisdiction procedure is used with the...

  1. Delay discounting of different commodities II: confirmatory analyses.

    PubMed

    Weatherly, Jeffrey N; Terrell, Heather K

    2011-01-01

    Delay discounting occurs when individuals are increasingly willing to accept less than the full amount of something to receive it immediately as the delay to the full amount increases. Previous research has reported different "domains" of commodities, with discounting in one domain not being informative about discounting in another. In the present study, 283 participants completed a delay-discounting task with 1 of 2 sets of 5 commodities identical to those used in previous research (Weatherly, Terrell, & Derenne, 2010). Confirmatory factor analyses determined that the observed discounting conformed to previously reported domains. Also replicated was finding that discounting differs both as a function of commodity and how the commodity is framed. These results provide strong support for the idea that temporal decisions made about certain consequences may not necessarily be informative about how an individual will make decisions about other consequences. Also, the framing of the decision can significantly influence observed levels of discounting, potentially clouding interpretation. PMID:21404948

  2. Statistical microeconomics and commodity prices: theory and empirical results.

    PubMed

    Baaquie, Belal E

    2016-01-13

    A review is made of the statistical generalization of microeconomics by Baaquie (Baaquie 2013 Phys. A 392, 4400-4416. (doi:10.1016/j.physa.2013.05.008)), where the market price of every traded commodity, at each instant of time, is considered to be an independent random variable. The dynamics of commodity market prices is given by the unequal time correlation function and is modelled by the Feynman path integral based on an action functional. The correlation functions of the model are defined using the path integral. The existence of the action functional for commodity prices that was postulated to exist in Baaquie (Baaquie 2013 Phys. A 392, 4400-4416. (doi:10.1016/j.physa.2013.05.008)) has been empirically ascertained in Baaquie et al. (Baaquie et al. 2015 Phys. A 428, 19-37. (doi:10.1016/j.physa.2015.02.030)). The model's action functionals for different commodities has been empirically determined and calibrated using the unequal time correlation functions of the market commodity prices using a perturbation expansion (Baaquie et al. 2015 Phys. A 428, 19-37. (doi:10.1016/j.physa.2015.02.030)). Nine commodities drawn from the energy, metal and grain sectors are empirically studied and their auto-correlation for up to 300 days is described by the model to an accuracy of R(2)>0.90-using only six parameters. PMID:26621991

  3. From Commodity Polymers to Functional Polymers

    PubMed Central

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications. PMID:24710333

  4. A study of thin liquid sheet flows

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Calfo, Frederick D.; Mcconley, Marc W.; Mcmaster, Matthew S.; Afjeh, Abdollah A.

    1993-01-01

    This study was a theoretical and experimental investigation of thin liquid sheet flows in vacuum. A sheet flow created by a narrow slit of width, W, coalesces to a point at a distance, L, as a result of surface tension forces acting at the sheet edges. As the flow coalesces, the fluid accumulates in the sheet edges. The observed triangular shape of the sheet agrees with the calculated triangular result. Experimental results for L/W as a function of Weber number, We, agree with the calculated result, L/W = the sq. root of 8We. The edge cross sectional shape is found to oscillate from elliptic to 'cigar' like to 'peanut' like and then back to elliptic in the flow direction. A theoretical one-dimensional model was developed that yielded only elliptic solutions for the edge cross section. At the points where the elliptic shapes occur, there is agreement between theory and experiment.

  5. Comparative Study of Airfoil Flow Separation Criteria

    NASA Astrophysics Data System (ADS)

    Laws, Nick; Kahouli, Waad; Epps, Brenden

    2015-11-01

    Airfoil flow separation impacts a multitude of applications including turbomachinery, wind turbines, and bio-inspired micro-aerial vehicles. In order to achieve maximum performance, some devices operate near the edge of flow separation, and others use dynamic flow separation advantageously. Numerous criteria exist for predicting the onset of airfoil flow separation. This talk presents a comparative study of a number of such criteria, with emphasis paid to speed and accuracy of the calculations. We evaluate the criteria using a two-dimensional unsteady vortex lattice method, which allows for rapid analysis (on the order of seconds instead of days for a full Navier-Stokes solution) and design of optimal airfoil geometry and kinematics. Furthermore, dynamic analyses permit evaluation of dynamic stall conditions for enhanced lift via leading edge vortex shedding, commonly present in small flapping-wing flyers such as the bumblebee and hummingbird.

  6. Lower Three Runs Instream Flow Study

    SciTech Connect

    del Carmen, B.R.; Paller, M.H.

    1993-12-31

    An Instream Flow Study was conducted to identify the minimum discharge from PAR Pond that will support a balanced biological fish community in Lower Three Runs. Hydraulic and habitat models of the Physical Habitat simulation System (PHABSIM), the major component of the US Fish and Wildlife Service`s Instream Flow Incremental Methodology (IFIM) were applied. Following calibration of the Water Surface Profile (WSP)Model for three study reaches, hydraulic data was input to the AVDEPTH habitat model to develop relationships between discharge and reaches, hydraulic data was input to the AVDEPTH habitat model to development relationship between discharge and available habitat.

  7. 75 FR 27338 - NASDAQ OMX Commodities Clearing-Contract Merchant LLC; NASDAQ OMX Commodities Clearing-Delivery...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-14

    ... Commodities Clearing--Delivery LLC; NASDAQ OMX Commodities Clearing--Finance LLC; Notice of Filing May 6, 2010... Commodities Clearing--Delivery LLC, and NASDAQ OMX Commodities Clearing--Finance LLC filed a supplement to...

  8. 17 CFR 33.3 - Unlawful commodity option transactions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Unlawful commodity option transactions. 33.3 Section 33.3 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF DOMESTIC EXCHANGE-TRADED COMMODITY OPTION TRANSACTIONS § 33.3 Unlawful commodity...

  9. 17 CFR 32.3 - Unlawful commodity option transactions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Unlawful commodity option transactions. 32.3 Section 32.3 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.3 Unlawful commodity option transactions. (a) On and...

  10. 17 CFR 32.11 - Suspension of commodity option transactions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Suspension of commodity option transactions. 32.11 Section 32.11 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.11 Suspension of commodity option transactions....

  11. Vortex dynamics studies in supersonic flow

    NASA Astrophysics Data System (ADS)

    Vergine, Fabrizio

    This dissertation covers the study of selected vortex interaction scenarios both in cold and high enthalpy reacting flows. Specifically, the experimental results and the analysis of the flowfields resulting from two selected supersonic vortex interaction modes in a Mach 2.5 cold flow are presented. Additionally, the experiment design, based on vortex dynamics concepts, and the reacting plume survey of two pylon injectors in a Mach 2.4 high enthalpy flow are shown. All the cold flow experiments were conducted in the supersonic wind tunnel of the Aerodynamics Research Center at the University of Texas at Arlington. A strut injector equipped with specified ramp configurations was designed and used to produce the flowfields of interest. The reacting flow experiments were conducted in the the Expansion Tube Facility located in the High Temperature Gasdynamics Laboratory of Stanford University. A detailed description of the supersonic wind tunnel, the instrumentation, the strut injector and the supersonic wake flow downstream is shown as part of the characterization of the facility. As Stereoscopic Particle Image Velocimetry was the principal flow measurement technique used in this work to probe the streamwise vortices shed from ramps mounted on the strut, this dissertation provides a deep overview of the challenges and the application of the aforementioned technique to the survey of vortical flows. Moreover, the dissertation provides the comprehensive analysis of the mean and fluctuating velocity flowfields associated with two distinct vortex dynamics scenarios, as chosen by means of the outcomes of the simulations of a reduced order model developed in the research group. Specifically, the same streamwise vortices (strength, size and Reynolds number) were used experimentally to investigate both a case in which the resulting dynamics evolve in a vortex merging scenario and a case where the merging process is voluntarily avoided in order to focus the analysis on the

  12. Parallel supercomputing with commodity components

    SciTech Connect

    Warren, M.S.; Goda, M.P.; Becker, D.J.

    1997-09-01

    We have implemented a parallel computer architecture based entirely upon commodity personal computer components. Using 16 Intel Pentium Pro microprocessors and switched fast ethernet as a communication fabric, we have obtained sustained performance on scientific applications in excess of one Gigaflop. During one production astrophysics treecode simulation, we performed 1.2 x 10{sup 15} floating point operations (1.2 Petaflops) over a three week period, with one phase of that simulation running continuously for two weeks without interruption. We report on a variety of disk, memory and network benchmarks. We also present results from the NAS parallel benchmark suite, which indicate that this architecture is competitive with current commercial architectures. In addition, we describe some software written to support efficient message passing, as well as a Linux device driver interface to the Pentium hardware performance monitoring registers.

  13. Parallel supercomputing with commodity components

    NASA Technical Reports Server (NTRS)

    Warren, M. S.; Goda, M. P.; Becker, D. J.

    1997-01-01

    We have implemented a parallel computer architecture based entirely upon commodity personal computer components. Using 16 Intel Pentium Pro microprocessors and switched fast ethernet as a communication fabric, we have obtained sustained performance on scientific applications in excess of one Gigaflop. During one production astrophysics treecode simulation, we performed 1.2 x 10(sup 15) floating point operations (1.2 Petaflops) over a three week period, with one phase of that simulation running continuously for two weeks without interruption. We report on a variety of disk, memory and network benchmarks. We also present results from the NAS parallel benchmark suite, which indicate that this architecture is competitive with current commercial architectures. In addition, we describe some software written to support efficient message passing, as well as a Linux device driver interface to the Pentium hardware performance monitoring registers.

  14. Development of a flow visualization apparatus. [to study convection flow patterns

    NASA Technical Reports Server (NTRS)

    Spradley, L. W.

    1975-01-01

    The use of an optical flow visualization device for studying convection flow patterns was investigated. The investigation considered use of a shadowgraph, schlieren and other means for visualizing the flow. A laboratory model was set up to provide data on the proper optics and photography procedures to best visualize the flow. A preliminary design of a flow visualization system is provided as a result of the study. Recommendations are given for a flight test program utilizing the flow visualization apparatus.

  15. Budget Constraints Affect Male Rats’ Choices between Differently Priced Commodities

    PubMed Central

    Kalenscher, Tobias

    2015-01-01

    Demand theory can be applied to analyse how a human or animal consumer changes her selection of commodities within a certain budget in response to changes in price of those commodities. This change in consumption assessed over a range of prices is defined as demand elasticity. Previously, income-compensated and income-uncompensated price changes have been investigated using human and animal consumers, as demand theory predicts different elasticities for both conditions. However, in these studies, demand elasticity was only evaluated over the entirety of choices made from a budget. As compensating budgets changes the number of attainable commodities relative to uncompensated conditions, and thus the number of choices, it remained unclear whether budget compensation has a trivial effect on demand elasticity by simply sampling from a different total number of choices or has a direct effect on consumers’ sequential choice structure. If the budget context independently changes choices between commodities over and above price effects, this should become apparent when demand elasticity is assessed over choice sets of any reasonable size that are matched in choice opportunities between budget conditions. To gain more detailed insight in the sequential choice dynamics underlying differences in demand elasticity between budget conditions, we trained N=8 rat consumers to spend a daily budget by making a number of nosepokes to obtain two liquid commodities under different price regimes, in sessions with and without budget compensation. We confirmed that demand elasticity for both commodities differed between compensated and uncompensated budget conditions, also when the number of choices considered was matched, and showed that these elasticity differences emerge early in the sessions. These differences in demand elasticity were driven by a higher choice rate and an increased reselection bias for the preferred commodity in compensated compared to uncompensated budget

  16. Budget Constraints Affect Male Rats' Choices between Differently Priced Commodities.

    PubMed

    van Wingerden, Marijn; Marx, Christine; Kalenscher, Tobias

    2015-01-01

    Demand theory can be applied to analyse how a human or animal consumer changes her selection of commodities within a certain budget in response to changes in price of those commodities. This change in consumption assessed over a range of prices is defined as demand elasticity. Previously, income-compensated and income-uncompensated price changes have been investigated using human and animal consumers, as demand theory predicts different elasticities for both conditions. However, in these studies, demand elasticity was only evaluated over the entirety of choices made from a budget. As compensating budgets changes the number of attainable commodities relative to uncompensated conditions, and thus the number of choices, it remained unclear whether budget compensation has a trivial effect on demand elasticity by simply sampling from a different total number of choices or has a direct effect on consumers' sequential choice structure. If the budget context independently changes choices between commodities over and above price effects, this should become apparent when demand elasticity is assessed over choice sets of any reasonable size that are matched in choice opportunities between budget conditions. To gain more detailed insight in the sequential choice dynamics underlying differences in demand elasticity between budget conditions, we trained N=8 rat consumers to spend a daily budget by making a number of nosepokes to obtain two liquid commodities under different price regimes, in sessions with and without budget compensation. We confirmed that demand elasticity for both commodities differed between compensated and uncompensated budget conditions, also when the number of choices considered was matched, and showed that these elasticity differences emerge early in the sessions. These differences in demand elasticity were driven by a higher choice rate and an increased reselection bias for the preferred commodity in compensated compared to uncompensated budget conditions

  17. Numerical Study of Tip Vortex Flows

    NASA Technical Reports Server (NTRS)

    Dacles-Mariani, Jennifer; Hafez, Mohamed

    1998-01-01

    This paper presents an overview and summary of the many different research work related to tip vortex flows and wake/trailing vortices as applied to practical engineering problems. As a literature survey paper, it outlines relevant analytical, theoretical, experimental and computational study found in literature. It also discusses in brief some of the fundamental aspects of the physics and its complexities. An appendix is also included. The topics included in this paper are: 1) Analytical Vortices; 2) Experimental Studies; 3) Computational Studies; 4) Wake Vortex Control and Management; 5) Wake Modeling; 6) High-Lift Systems; 7) Issues in Numerical Studies; 8) Instabilities; 9) Related Topics; 10) Visualization Tools for Vertical Flows; 11) Further Work Needed; 12) Acknowledgements; 13) References; and 14) Appendix.

  18. Experimental studies of rotating exchange flow

    NASA Astrophysics Data System (ADS)

    Rabe, B.; Smeed, D. A.; Dalziel, S. B.; Lane-Serff, G. F.

    2007-02-01

    Ocean basins are connected by straits and passages, geometrically limiting important heat and salt exchanges which in turn influence the global thermohaline circulation and climate. Such exchange can be modeled in an idealized way by taking into consideration the density-driven two-layer flow along a strait under the influence of rotation. We use a laboratory model of a lock exchange between two reservoirs of different density through a flat-bottom channel with a horizontal narrows, set up on two different platforms: a 1 m diameter turntable, where density interface position was measured by dye attenuation, and the 14 m diameter turntable at Coriolis/LEGI (Grenoble, France), where correlation imaging velocimetry, a particle imaging technique, allowed us to obtain for the first time detailed measurements of the velocity fields in these flows. The influence of rotation is studied by varying a parameter, Bu, a type of Burger number given by the ratio of the Rossby radius to the channel width at the narrows. In addition, a two-layer version of the Miami Isopycnic Coordinate Model (MICOM) is used, to study the cases with low Burger number. Results from experiments by Dalziel [1988. Two-layer hydraulics: maximal exchange flows. Ph.D. Thesis, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, see also ] are also included for comparison. Time-mean exchange fluxes for any Bu are in close agreement with the inviscid zero-potential vorticity theory of Dalziel [1990. Rotating two-layer sill flows. In: Pratt, L.J. (Ed.), The Physical Oceanography of Sea Straits. Kluwer Academic, Dordrecht, pp. 343-371] and Whitehead et al. [1974. Rotating hydraulics of strait and sill flows. Geophysical Fluid Dynamics 6, 101-125], who found that fluxes for Bu>1 mainly vary with channel width, similar to non-rotating flow, but for Bu<1 are only limited by the Rossby radius. We also show

  19. Comparative study of pressure-flow parameters.

    PubMed

    Eri, Lars M; Wessel, Nicolai; Tysland, Ole; Berge, Viktor

    2002-01-01

    Methods for quantification of bladder outlet obstruction (BOO) are still controversial. Parameters such as detrusor opening pressure (p(det.open)), maximum detrusor pressure (p(det.max)), minimum voiding pressure (p(det.min.void)), and detrusor pressure at maximum flow rate (P(det.Qmax)) separate obstructed from nonobstructed patients to some extent, but two nomograms, the Abrams-Griffiths nomogram and the linearized passive urethral resistance relation (LinPURR), are more accepted for this purpose, along with the urethral resistance algorithm. In this retrospective, methodologic study, we evaluated the properties of these parameters with regard to test-retest reproducibility and ability to detect a moderate (pharmacologic) and a pronounced (surgical) relief of bladder outlet obstruction. We studied the pressure-flow charts of 42 patients who underwent 24 weeks of androgen suppressive therapy, 42 corresponding patients who received placebo, and 30 patients who had prostate surgery. The patients performed repeat void pressure-flow examinations before and after treatment or placebo. The various parameters were compared. Among the bladder pressure parameters, P(det.Qmax) seemed to have some advantages, supporting the belief that it is the most relevant detrusor pressure parameter to include in nomograms to quantify BOO. In assessment of a large decrease in urethral resistance, such as after TURp, resistance parameters that are based on maximum flow rate as well as detrusor pressure are preferable. PMID:11948710

  20. Visual study of the effect of grazing flow on the oscillatory flow in a resonator orifice

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Rice, E. J.

    1975-01-01

    Grazing flow and oscillatory flow in an orifice were studied in a plexiglass flow channel with a single side branch Helmholtz resonator using water as the fluid medium. An oscillatory flow was applied to the resonatory cavity, and color dyes were injected in both the orifice and the grazing flow field to record the motion of the fluid. The flow regimes associated with linear and nonlinear (high sound pressure level) impedances with and without grazing flows were recorded by a high-speed motion-picture camera. Appreciable differences in the oscillatory flow field were seen in the various flow regimes. With high grazing flows, the outflow and inflow from the resonator cavity are found to be asymmetric. The visual study confirms that jet energy loss during flow into a resonator cavity is much larger than the loss for ejection from the cavity into the grazing flow. For inflow into the resonator cavity, the effective orifice area was significantly reduced.

  1. Performance study of a data flow architecture

    NASA Technical Reports Server (NTRS)

    Adams, George

    1985-01-01

    Teams of scientists studied data flow concepts, static data flow machine architecture, and the VAL language. Each team mapped its application onto the machine and coded it in VAL. The principal findings of the study were: (1) Five of the seven applications used the full power of the target machine. The galactic simulation and multigrid fluid flow teams found that a significantly smaller version of the machine (16 processing elements) would suffice. (2) A number of machine design parameters including processing element (PE) function unit numbers, array memory size and bandwidth, and routing network capability were found to be crucial for optimal machine performance. (3) The study participants readily acquired VAL programming skills. (4) Participants learned that application-based performance evaluation is a sound method of evaluating new computer architectures, even those that are not fully specified. During the course of the study, participants developed models for using computers to solve numerical problems and for evaluating new architectures. These models form the bases for future evaluation studies.

  2. Supply of and demand for selected energy related mineral commodities

    USGS Publications Warehouse

    Sibley, Scott F.

    2010-01-01

    In this report, subjects discussed include components of mineral supply, production, and consumption data, and information on selected mineral commodities in which the Energy Critical Elements Study Group has an interest, and U.S. Geological Survey (USGS) recycling studies, with some results of these studies.

  3. Axial compressor middle stage secondary flow study

    NASA Technical Reports Server (NTRS)

    Wagner, J. H.; Dring, R. P.; Joslyn, H. D.

    1983-01-01

    This report describes an experimental investigation of the secondary flow within and aft of an axial compressor model with thick endwall boundary layers. The objective of the study was to obtain detailed aerodynamic and trace gas concentration traverse data aft of a well documented isolated rotor for the ultimate purpose of improving the design phases of compressor development based on an improved physical understanding of secondary flow. It was determined from the flow visualization, aerodynamic, and trace gas concentration results that the relative unloading of the midspan region of the airfoil inhibitied a fullspan separation at high loading preventing the massive radial displacement of the hub corner stall to the tip. Radial distribution of high and low total pressure fluid influenced the magnitude of the spanwise distribution of loss, such that, there was a general decreases in loss near the hub to the extent that for the least loaded case a negative loss (increase in total pressure) was observed. The ability to determine the spanwise distribution of blockage was demonstrated. Large blockage was present in the endwall regions due to the corner stall and tip leakage with little blockage in the core flow region. Hub blockage was found to increase rapidly with loading.

  4. Experimental Study of Flow in a Bifurcation

    NASA Astrophysics Data System (ADS)

    Fresconi, Frank; Prasad, Ajay

    2003-11-01

    An instability known as the Dean vortex occurs in curved pipes with a longitudinal pressure gradient. A similar effect is manifest in the flow in a converging or diverging bifurcation, such as those found in the human respiratory airways. The goal of this study is to characterize secondary flows in a bifurcation. Particle image velocimetry (PIV) and laser-induced fluorescence (LIF) experiments were performed in a clear, plastic model. Results show the strength and migration of secondary vortices. Primary velocity features are also presented along with dispersion patterns from dye visualization. Unsteadiness, associated with a hairpin vortex, was also found at higher Re. This work can be used to assess the dispersion of particles in the lung. Medical delivery systems and pollution effect studies would profit from such an understanding.

  5. 44 CFR 206.151 - Food commodities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Food commodities. 206.151... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Other Individual Assistance § 206.151 Food commodities. (a) The Administrator will assure that adequate stocks of food will be ready...

  6. 44 CFR 206.151 - Food commodities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Food commodities. 206.151... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Other Individual Assistance § 206.151 Food commodities. (a) The Administrator will assure that adequate stocks of food will be ready...

  7. 44 CFR 206.151 - Food commodities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Food commodities. 206.151 Section 206.151 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Other Individual Assistance § 206.151 Food commodities. (a) The Administrator...

  8. 44 CFR 206.151 - Food commodities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Food commodities. 206.151... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Other Individual Assistance § 206.151 Food commodities. (a) The Administrator will assure that adequate stocks of food will be ready...

  9. 44 CFR 206.151 - Food commodities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false Food commodities. 206.151... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Other Individual Assistance § 206.151 Food commodities. (a) The Administrator will assure that adequate stocks of food will be ready...

  10. 7 CFR 65.135 - Covered commodity.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... OF BEEF, PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS... means: (1) Muscle cuts of beef, lamb, chicken, goat, and pork; (2) Ground beef, ground lamb, ground chicken, ground goat, and ground pork; (3) Perishable agricultural commodities; (4) Peanuts; (5)...

  11. 7 CFR 65.135 - Covered commodity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... OF BEEF, PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS... means: (1) Muscle cuts of beef, lamb, chicken, goat, and pork; (2) Ground beef, ground lamb, ground chicken, ground goat, and ground pork; (3) Perishable agricultural commodities; (4) Peanuts; (5)...

  12. 7 CFR 65.135 - Covered commodity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... OF BEEF, PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS... means: (1) Muscle cuts of beef, lamb, chicken, goat, and pork; (2) Ground beef, ground lamb, ground chicken, ground goat, and ground pork; (3) Perishable agricultural commodities; (4) Peanuts; (5)...

  13. 7 CFR 65.135 - Covered commodity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... OF BEEF, PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS... means: (1) Muscle cuts of beef, lamb, chicken, goat, and pork; (2) Ground beef, ground lamb, ground chicken, ground goat, and ground pork; (3) Perishable agricultural commodities; (4) Peanuts; (5)...

  14. 7 CFR 65.135 - Covered commodity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... OF BEEF, PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS... means: (1) Muscle cuts of beef, lamb, chicken, goat, and pork; (2) Ground beef, ground lamb, ground chicken, ground goat, and ground pork; (3) Perishable agricultural commodities; (4) Peanuts; (5)...

  15. 7 CFR 1405.9 - Commodity assessments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Commodity assessments. 1405.9 Section 1405.9... Commodity assessments. (a) CCC will deduct from the proceeds of a marketing assistance loan an amount equal to the amount of an assessment otherwise required to be remitted to a State agency under a...

  16. 7 CFR 60.105 - Covered commodity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... FOR FISH AND SHELLFISH General Provisions Definitions § 60.105 Covered commodity. (a) Covered commodity means: (1)-(2) (3) Farm-raised fish and shellfish (including fillets, steaks, nuggets, and any other flesh); (4) Wild fish and shellfish (including fillets, steaks, nuggets, and any other flesh);...

  17. 7 CFR 60.105 - Covered commodity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FOR FISH AND SHELLFISH General Provisions Definitions § 60.105 Covered commodity. (a) Covered commodity means: (1)-(2) (3) Farm-raised fish and shellfish (including fillets, steaks, nuggets, and any other flesh); (4) Wild fish and shellfish (including fillets, steaks, nuggets, and any other flesh);...

  18. 7 CFR 60.105 - Covered commodity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... FOR FISH AND SHELLFISH General Provisions Definitions § 60.105 Covered commodity. (a) Covered commodity means: (1)-(2) (3) Farm-raised fish and shellfish (including fillets, steaks, nuggets, and any other flesh); (4) Wild fish and shellfish (including fillets, steaks, nuggets, and any other flesh);...

  19. 7 CFR 60.105 - Covered commodity.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... FOR FISH AND SHELLFISH General Provisions Definitions § 60.105 Covered commodity. (a) Covered commodity means: (1)-(2) (3) Farm-raised fish and shellfish (including fillets, steaks, nuggets, and any other flesh); (4) Wild fish and shellfish (including fillets, steaks, nuggets, and any other flesh);...

  20. 7 CFR 1401.4 - Commodity certificates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Federal statute. (3) The provisions of this paragraph (b) shall apply without regard to the identity of... available for exchange and the procedure for exchange from Kansas City Commodity Office, FSA-USDA, Kansas City, MO 64141-0205. (2) Minimum quantities. A holder of an amount of commodity certificates...

  1. 7 CFR 1405.9 - Commodity assessments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Commodity assessments. 1405.9 Section 1405.9... Commodity assessments. (a) CCC will deduct from the proceeds of a marketing assistance loan an amount equal to the amount of an assessment otherwise required to be remitted to a State agency under a...

  2. 7 CFR 1401.4 - Commodity certificates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... FORMS OF PAYMENT § 1401.4 Commodity certificates. (a) General. CCC may issue commodity certificates as a... transferred, exchanged for the inventory of CCC (including the receipt in accordance with paragraph (e) of... and the date of the transfer, and signed by the transferor. CCC will not honor any certificate...

  3. 7 CFR 1401.4 - Commodity certificates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FORMS OF PAYMENT § 1401.4 Commodity certificates. (a) General. CCC may issue commodity certificates as a... transferred, exchanged for the inventory of CCC (including the receipt in accordance with paragraph (e) of... and the date of the transfer, and signed by the transferor. CCC will not honor any certificate...

  4. 7 CFR 1401.4 - Commodity certificates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... FORMS OF PAYMENT § 1401.4 Commodity certificates. (a) General. CCC may issue commodity certificates as a... transferred, exchanged for the inventory of CCC (including the receipt in accordance with paragraph (e) of... and the date of the transfer, and signed by the transferor. CCC will not honor any certificate...

  5. Mycotoxin contamination of commercially important agricultural commodities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungal toxins, called aflatoxins and other mold toxins, are a serious problem in US agricultural commodities. Due to aflatoxins resilience to industrial processes contaminated crops (corn, cotton, peanuts, and tree nuts) cannot be used. The loss of these commodities results in serious economic impa...

  6. Transient studies of capillary-induced flow

    NASA Technical Reports Server (NTRS)

    Reagan, M. K.; Bowman, W. J.

    1993-01-01

    This paper presents the numerical and experimental results of a study performed on the transient rise of fluid in a capillary tube. The capillary tube problem provides an excellent mechanism from which to launch an investigation into the transient flow of a fluid in a porous wick structure where capillary forces must balance both adverse gravitational effects and frictional losses. For the study, a capillary tube, initially charged with a small volume of water, was lowered into a pool of water. The behavior of the column of fluid during the transient that followed as more water entered the tube from the pool was both numerically and experimentally studied.

  7. Scientific Research: Commodities or Commons?

    NASA Astrophysics Data System (ADS)

    Vermeir, Koen

    2013-10-01

    Truth is for sale today, some critics claim. The increased commodification of science corrupts it, scientific fraud is rampant and the age-old trust in science is shattered. This cynical view, although gaining in prominence, does not explain very well the surprising motivation and integrity that is still central to the scientific life. Although scientific knowledge becomes more and more treated as a commodity or as a product that is for sale, a central part of academic scientific practice is still organized according to different principles. In this paper, I critically analyze alternative models for understanding the organization of knowledge, such as the idea of the scientific commons and the gift economy of science. After weighing the diverse positive and negative aspects of free market economies of science and gift economies of science, a commons structured as a gift economy seems best suited to preserve and take advantage of the specific character of scientific knowledge. Furthermore, commons and gift economies promote the rich social texture that is important for supporting central norms of science. Some of these basic norms might break down if the gift character of science is lost. To conclude, I consider the possibility and desirability of hybrid economies of academic science, which combine aspects of gift economies and free market economies. The aim of this paper is to gain a better understanding of these deeper structural challenges faced by science policy. Such theoretical reflections should eventually assist us in formulating new policy guidelines.

  8. A Java commodity grid kit.

    SciTech Connect

    von Laszewski, G.; Foster, I.; Gawor, J.; Lane, P.; Mathematics and Computer Science

    2001-07-01

    In this paper we report on the features of the Java Commodity Grid Kit. The Java CoG Kit provides middleware for accessing Grid functionality from the Java framework. Java CoG Kit middleware is general enough to design a variety of advanced Grid applications with quite different user requirements. Access to the Grid is established via Globus protocols, allowing the Java CoG Kit to communicate also with the C Globus reference implementation. Thus, the Java CoG Kit provides Grid developers with the ability to utilize the Grid, as well as numerous additional libraries and frameworks developed by the Java community to enable network, Internet, enterprise, and peer-to peer computing. A variety of projects have successfully used the client libraries of the Java CoG Kit to access Grids driven by the C Globus software. In this paper we also report on the efforts to develop server side Java CoG Kit components. As part of this research we have implemented a prototype pure Java resource management system that enables one to run Globus jobs on platforms on which a Java virtual machine is supported, including Windows NT machines.

  9. Study of argon–oxygen flowing afterglow

    NASA Astrophysics Data System (ADS)

    Mazánková, V.; Trunec, D.; Navrátil, Z.; Raud, J.; Krčma, F.

    2016-06-01

    The reaction kinetics in argon–oxygen flowing afterglow (post-discharge) was studied using NO titration and optical emission spectroscopy. The flowing DC post-discharge in argon–oxygen mixture was created in a quartz tube at the total gas pressure of 1000 Pa and discharge power of 90 W. The O(3P) atom concentration was determined by NO titration at different places along the flow tube. The optical emission spectra were also measured along the flow tube. Argon spectral lines, oxygen lines at 777 nm and 844.6 nm and atmospheric A-band of {{\\text{O}}2} were identified in the spectra. Rotational temperature of {{\\text{O}}2} was determined from the oxygen atmospheric A-band and also the outer wall temperature of the flow tube was measured by a thermocouple and by an IR thermometer. A zero-dimensional kinetic model for the reactions in the afterglow was developed. This model allows the time dependencies of particle concentrations and of gas temperature to be calculated. The wall recombination probability for O(3P) atoms {γ\\text{O≤ft(\\text{P}\\right)}}=≤ft(1.63+/- 0.06\\right)× {{10}-3} and wall deactivation probability for {{\\text{O}}2} (b {{}1}Σ\\text{g}+ ) molecules {γ{{\\text{O}2}≤ft(\\text{b}\\right)}}=≤ft(1.7+/- 0.1\\right)× {{10}-3} were determined from the fit of model results to experimental data. Sensitivity analysis was applied for the analysis of kinetic model in order to reveal the most important reactions in the model. The calculated gas temperature increases in the afterglow and then decreases at later afterglow times after reaching the maximum. This behavior is in good agreement with the spatial rotational temperature dependence. A similar trend was also observed at outer wall temperature measurement.

  10. Effects of Regulation and Technology on End Uses of Nonfuel Mineral Commodities in the United States

    USGS Publications Warehouse

    Matos, Grecia R.

    2007-01-01

    The regulatory system and advancement of technologies have shaped the end-use patterns of nonfuel minerals used in the United States. These factors affected the quantities and types of materials used by society. Environmental concerns and awareness of possible negative effects on public health prompted numerous regulations that have dramatically altered the use of commodities like arsenic, asbestos, lead, and mercury. While the selected commodities represent only a small portion of overall U.S. materials use, they have the potential for harmful effects on human health or the environment, which other commodities, like construction aggregates, do not normally have. The advancement of technology allowed for new uses of mineral materials in products like high-performance computers, telecommunications equipment, plasma and liquid-crystal display televisions and computer monitors, mobile telephones, and electronic devices, which have become mainstream products. These technologies altered the end-use pattern of mineral commodities like gallium, germanium, indium, and strontium. Human ingenuity and people?s demand for different and creative services increase the demand for new materials and industries while shifting the pattern of use of mineral commodities. The mineral commodities? end-use data are critical for the understanding of the magnitude and character of these flows, assessing their impact on the environment, and providing an early warning of potential problems in waste management of products containing these commodities. The knowledge of final disposition of the mineral commodity allows better decisions as to how regulation should be tailored.

  11. Trading forests: land-use change and carbon emissions embodied in production and exports of forest-risk commodities

    NASA Astrophysics Data System (ADS)

    Henders, Sabine; Persson, U. Martin; Kastner, Thomas

    2015-12-01

    Production of commercial agricultural commodities for domestic and foreign markets is increasingly driving land clearing in tropical regions, creating links and feedback effects between geographically separated consumption and production locations. Such teleconnections are commonly studied through calculating consumption footprints and quantifying environmental impacts embodied in trade flows, e.g., virtual water and land, biomass, or greenhouse gas emissions. The extent to which land-use change (LUC) and associated carbon emissions are embodied in the production and export of agricultural commodities has been less studied. Here we quantify tropical deforestation area and carbon emissions from LUC induced by the production and the export of four commodities (beef, soybeans, palm oil, and wood products) in seven countries with high deforestation rates (Argentina, Bolivia, Brazil, Paraguay, Indonesia, Malaysia, and Papua New Guinea). We show that in the period 2000-2011, the production of the four analyzed commodities in our seven case countries was responsible for 40% of total tropical deforestation and resulting carbon losses. Over a third of these impacts was embodied in exports in 2011, up from a fifth in 2000. This trend highlights the growing influence of global markets in deforestation dynamics. Main flows of embodied LUC are Latin American beef and soybean exports to markets in Europe, China, the former Soviet bloc, the Middle East and Northern Africa, whereas embodied emission flows are dominated by Southeast Asian exports of palm oil and wood products to consumers in China, India and the rest of Asia, as well as to the European Union. Our findings illustrate the growing role that global consumers play in tropical LUC trajectories and highlight the need for demand-side policies covering whole supply chains. We also discuss the limitations of such demand-side measures and call for a combination of supply- and demand-side policies to effectively limit tropical

  12. 17 CFR 31.6 - Registration of leverage commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Registration of leverage commodities. 31.6 Section 31.6 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION LEVERAGE TRANSACTIONS § 31.6 Registration of leverage commodities. (a) Registration of leverage...

  13. 17 CFR 37.3 - Requirements for underlying commodities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... commodities. 37.3 Section 37.3 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION DERIVATIVES TRANSACTION EXECUTION FACILITIES § 37.3 Requirements for underlying commodities. (a) Trading... 5a(b)(3) of the Act, may trade any contract of sale of a commodity for future delivery (or option...

  14. Fan Stall Flutter Flow Mechanism Studied

    NASA Technical Reports Server (NTRS)

    Lepicovsky, Jan

    2002-01-01

    Modern turbofan engines employ a highly loaded fan stage with transonic or low-supersonic velocities in the blade-tip region. The fan blades are often prone to flutter at off-design conditions. Flutter is a highly undesirable and dangerous self-excited mode of blade oscillations that can result in high-cycle fatigue blade failure. The origins of blade flutter are not fully understood yet. Experimental data that can be used to clarify the origins of blade flutter in modern transonic fan designs are very limited. The Transonic Flutter Cascade Facility at the NASA Glenn Research Center was developed to experimentally study the details of flow mechanisms associated with fan flutter. The cascade airfoils are instrumented to measure high-frequency unsteady flow variations in addition to the steady flow data normally recorded in cascade tests. The test program measures the variation in surface pressure in response to the oscillation of one or more of the cascade airfoils. However, during the initial phases of the program when all airfoils were in fixed positions, conditions were found where significant time variations in the pressures near the airfoil leading edges could be observed.

  15. Space shuttle orbiter flow visualization study. [water tunnel study of vortex flow during atmospheric entry

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1980-01-01

    The vortex flows generated at subsonic speed during the final portion of atmospheric reentry were defined using a 0.01 scale model of the orbiter in a diagnostic water tunnel. Flow visualization photographs were obtained over an angle-of-attack range to 40 deg and sideslip angles up to 10 deg. The vortex flow field development, vortex path, and vortex breakdown characteristics were determined as a function of angle-of-attack at zero sideslip. Vortex flows were found to develop on the highly swept glove, on the wing, and on the upper surface of the fuselage. No significant asymmetries were observed at zero sideslip in the water tunnel tests. The sensitivity of the upper surface vortex flow fields to variations in sideslip angle was also studied. The vortex formed on the glove remained very stable in position above the wing up through the 10 deg of sideslip tested. There was a change in the vortex lifts under sideslip due to effective change in leading-edge sweep angles. Asymmetric flow separation occurred on the upper surface of the fuselage at small sideslip angles. The influence of vortex flow fields in sideslip on the lateral/ directional characteristics of the orbiter is discussed.

  16. Gold recycling; a materials flow study

    USGS Publications Warehouse

    Amey, Earle B.

    2000-01-01

    This materials flow study includes a description of trends in consumption, loss, and recycling of gold-containing materials in the United States in 1998 in order to illustrate the extent to which gold is presently being recycled and to identify recycling trends. The quantity of gold recycled, as a percent of the apparent supply of gold, was estimated to be about 30 percent. Of the approximately 446 metric tons of gold refined in the United States in 1998, the fabricating and industrial use losses were 3 percent.

  17. A study of grout flow pattern analysis

    SciTech Connect

    Lee, S. Y.; Hyun, S.

    2013-01-10

    A new disposal unit, designated as Salt Disposal Unit no. 6 (SDU6), is being designed for support of site accelerated closure goals and salt nuclear waste projections identified in the new Liquid Waste System plan. The unit is cylindrical disposal vault of 380 ft diameter and 43 ft in height, and it has about 30 million gallons of capacity. Primary objective was to develop the computational model and to perform the evaluations for the flow patterns of grout material in SDU6 as function of elevation of grout discharge port, and slurry rheology. A Bingham plastic model was basically used to represent the grout flow behavior. A two-phase modeling approach was taken to achieve the objective. This approach assumes that the air-grout interface determines the shape of the accumulation mound. The results of this study were used to develop the design guidelines for the discharge ports of the Saltstone feed materials in the SDU6 facility. The focusing areas of the modeling study are to estimate the domain size of the grout materials radially spread on the facility floor under the baseline modeling conditions, to perform the sensitivity analysis with respect to the baseline design and operating conditions such as elevation of discharge port, discharge pipe diameter, and grout properties, and to determine the changes in grout density as it is related to grout drop height. An axi-symmetric two-phase modeling method was used for computational efficiency. Based on the nominal design and operating conditions, a transient computational approach was taken to compute flow fields mainly driven by pumping inertia and natural gravity. Detailed solution methodology and analysis results are discussed here.

  18. 29 CFR 780.114 - Wild commodities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... animals, or the appropriation of minerals and other uncultivated products from the soil are not employed... horticultural commodities.” Transplanted branches which were cut from plants growing wild in the field or...

  19. 44 CFR 402.2 - Restricted commodities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Positive List (15 CFR part 399) (as amended from time to time) of the Comprehensive Export Schedule of the... T-2 which applies to all commodities destined to Communist China. Order T-1 does not relax or...

  20. 44 CFR 402.2 - Restricted commodities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Positive List (15 CFR part 399) (as amended from time to time) of the Comprehensive Export Schedule of the... T-2 which applies to all commodities destined to Communist China. Order T-1 does not relax or...

  1. 44 CFR 402.2 - Restricted commodities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Positive List (15 CFR part 399) (as amended from time to time) of the Comprehensive Export Schedule of the... T-2 which applies to all commodities destined to Communist China. Order T-1 does not relax or...

  2. 44 CFR 402.2 - Restricted commodities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Positive List (15 CFR part 399) (as amended from time to time) of the Comprehensive Export Schedule of the... T-2 which applies to all commodities destined to Communist China. Order T-1 does not relax or...

  3. 44 CFR 402.2 - Restricted commodities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Positive List (15 CFR part 399) (as amended from time to time) of the Comprehensive Export Schedule of the... T-2 which applies to all commodities destined to Communist China. Order T-1 does not relax or...

  4. 29 CFR 780.114 - Wild commodities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... harvesting of wild commodities such as mosses, wild rice, burls and laurel plants, the trapping of wild... in “the production, cultivation, growing, and harvesting of agricultural or horticultural...

  5. Accelerating semantic graph databases on commodity clusters

    SciTech Connect

    Morari, Alessandro; Castellana, Vito G.; Haglin, David J.; Feo, John T.; Weaver, Jesse R.; Tumeo, Antonino; Villa, Oreste

    2013-10-06

    We are developing a full software system for accelerating semantic graph databases on commodity cluster that scales to hundreds of nodes while maintaining constant query throughput. Our framework comprises a SPARQL to C++ compiler, a library of parallel graph methods and a custom multithreaded runtime layer, which provides a Partitioned Global Address Space (PGAS) programming model with fork/join parallelism and automatic load balancing over a commodity clusters. We present preliminary results for the compiler and for the runtime.

  6. A study of temporal estaurine flow dynamics

    NASA Technical Reports Server (NTRS)

    Mairs, R. L.; Clark, D. K.

    1972-01-01

    Multispectral photography,infrared imagery, image enhancement, and oceanographic, radiometric, and meteorological data were used in the study of temporal estuarine flow dynamics, nearshore circulation, and the resulting dispersal of suspended and dissolved substances introduced from the continent. Repetitive multispectral photography, IR imagery, total radiance and irradiance, water surface temperatures, salinity, total suspended solids, visibility, current velocity, winds, dye implants, and high contrast image enhancement were used to observe and describe water mass boundaries in the nearshore zone and to attempt to establish on what repetitive scale these coastal features should be observed to better understand their behavior. Water mass variability patterns, seen naturally and with the use of dyes, along the North Carolina coast and in the Chesapeake Bay are being studied as synoptic data on the basic dynamics of circulation, flushing, and mixing in coastal waters.

  7. 7 CFR 1421.110 - Commodity certificate exchanges.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... COMMODITIES-MARKETING ASSISTANCE LOANS AND LOAN DEFICIENCY PAYMENTS FOR 2008 THROUGH 2012 Marketing Assistance... assistance loan collateral. (3) Immediately exchanging the purchased commodity certificate for...

  8. 7 CFR 1421.110 - Commodity certificate exchanges.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... COMMODITIES-MARKETING ASSISTANCE LOANS AND LOAN DEFICIENCY PAYMENTS FOR 2008 THROUGH 2012 Marketing Assistance... assistance loan collateral. (3) Immediately exchanging the purchased commodity certificate for...

  9. Recent Development in Hot Flow Anomaly Studies

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Wang, S.; Zong, Q.

    2013-05-01

    Hot flow anomalies (HFAs) are events observed near the bow shock that are characterized by greatly heated solar wind plasmas and substantial flow deflection from the Sun-Earth direction, with duration of a few minutes and scale size of the order of a few Re. HFAs are thought to be produced by the interaction of some very special interplanetary current sheets that satisfy several strict conditions with planetary bow shocks. When the current sheet (discontinuity) is connected to the bow shock and the motional electric fields point towards the discontinuity, ions reflected from the bow shock are trapped in the current sheet. The relative streaming energy of the original solar wind beam and the reflected beam is converted to the thermal energy. However, we found recently that HFAs can be generated spontaneously (in the absence of any current sheets) at quasi-parallel bow shocks where the interplanetary magnetic field lies nearly parallel to the shock normal. Statistical studies show that 60% of the HFAs are not associated with clear discontinuities. In addition, there are 13% of the HFAs with the motional electric fields on neither leading nor trailing edge pointing towards the discontinuity. These new results indicate that this phenomenon is still not well understood although it was discovered almost 30 years ago.

  10. Recent Development in Hot Flow Anomaly Studies

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Wang, S.; Zong, Q.

    2013-12-01

    Hot flow anomalies (HFAs) are events observed near the bow shock that are characterized by greatly heated solar wind plasmas and substantial flow deflection from the Sun-Earth direction, with duration of a few minutes and scale size of the order of a few RE. HFAs are thought to be produced by the interaction of some very special interplanetary current sheets that satisfy several strict conditions with planetary bow shocks. When the current sheet (discontinuity) is connected to the bow shock and the motional electric fields point towards the discontinuity, ions reflected from the bow shock are trapped in the current sheet. The relative streaming energy of the original solar wind beam and the reflected beam is converted to the thermal energy. However, we found recently that HFAs can be generated spontaneously (in the absence of any current sheets) at quasi-parallel bow shocks where the interplanetary magnetic field lies nearly parallel to the shock normal. Statistical studies show that 60% of the HFAs are not associated with clear discontinuities. In addition, there are 13% of the HFAs with the motional electric fields on neither leading nor trailing edge pointing towards the discontinuity. These new results indicate that this phenomenon is still not well understood although it was discovered almost 30 years ago.

  11. Performance Mapping Studies in Redox Flow Cells

    NASA Technical Reports Server (NTRS)

    Hoberecht, M. A.; Thaller, L. H.

    1981-01-01

    Pumping power requirements in any flow battery system constitute a direct parasitic energy loss. It is therefore useful to determine the practical lower limit for reactant flow rates. Through the use of a theoretical framework based on electrochemical first principles, two different experimental flow mapping techniques were developed to evaluate and compare electrodes as a function of flow rate. For the carbon felt electrodes presently used in NASA-Lewis Redox cells, a flow rate 1.5 times greater than the stoichiometric rate seems to be the required minimum.

  12. Effect of blood flow parameters on flow patterns at arterial bifurcations--studies in models.

    PubMed

    Liepsch, D W

    1990-01-01

    Atherosclerotic lesions are found primarily at arterial bends and bifurcations. Flow disturbances at these anatomic sites play a major role in atherogenesis. How hemodynamic factors such as vessel geometry, the pulsatile nature of blood flow, vessel wall elasticity and the non-Newtonian flow behavior of blood influence the flow field at these sites must be clarified. We have performed fundamental studies using a birefringent solution in a simplified rigid 90 degree T-bifurcation and pulsatile flow. The velocity distribution was measured with a laser Doppler anemometer. Flow in an elastic abdominal aorta model has been visualized using magnetic resonance imaging. In both flow studies, zones with negative velocity were found. These model measurements demonstrate that no flow parameter can be neglected. Further detailed studies are necessary to examine the interaction between fluid dynamic and cellular surface properties. PMID:2404201

  13. Advances in turbulence studies. [Magnetohydrodynamic flows

    SciTech Connect

    Branover, H.; Unger, Y.

    1993-01-01

    Important contemporary trends in both experimental and theoretical turbulence research are reported. Particular attention is given to vortex reconnection, cascade, and mixing in turbulent flows; intermittent turbulence from closures; tearing instabilities in 2D MHD turbulence; axisymmetric hydromagnetic dynamo; bifurcations in MHD flow generated by electric current discharge; renormalization group analysis of MHD turbulence with low magnetic Reynolds number; Solution for turbulent primary azimuthal velocity in liquid-metal flows in sliding electric contacts; analogies between geophysical and hydromagnetic flows; turbulent electrically-induced vortical flows; dissipation length scale dynamics; two-phase grid turbulence; abridged octave wavenumber ring models for 2D turbulence; rag theory of magnetic fluctuations in turbulent flow; and instabilities of the nonuniform flows of a low-temperature plasma in MHD channels.

  14. Numerical study of subcritical flow with fluid injection

    NASA Technical Reports Server (NTRS)

    Balasubramanian, R.

    1990-01-01

    It is suggested that the study of synthetic flows, where controlled experiments can be performed, is useful in understanding turbulent flow structures. The early states of formation of hairpin structures in shear flows and the subsequent evolution of these structures is studied in shear flows and the subsequent evolution of these structures is studied through numerical simulations, by developing full-time dependent three-dimensional flow solution of an initially laminar (subcritical) flow in which injection of fluid through a narrow streamwise slot from the bottom wall of a plate is carried out. Details of the numerical approach and significance of the present findings are reported in this work.

  15. Flow studies and particulate collection measurements

    SciTech Connect

    Greiner, G.P.; Furlong, D.A.; Bahner, M.A.

    1990-04-01

    This report describes testing of a Reduced Entrainment electrostatic Precipitator (REP) that has a portion of the main precipitator flow drawn through a porous (fabric) collecting surface. Tests investigated effects of flow through the collecting surface (side flow) on precipitator turbulence and particulate removal efficiency. Testing focused on these effects as being significant to the collection of fine (less than 10 microns) particulate. 17 refs., 41 figs., 10 tabs.

  16. Flow visualization studies of the internal flow characteristics in a simulated mixed flow vectored thrust ASTOVL engine configuration

    NASA Technical Reports Server (NTRS)

    Saripalli, K. R.; Ferraro, P. J.; Flood, J. D.; Grey, R. E.; Wazyniak, J. A.

    1991-01-01

    The characteristics of internal flowfields in a Mixed Flow Vectored Thrust (MFVT) propulsion system for Short Take Off and Vertical Landing (STOVL) fighter aircraft were investigated using flow visualization techniques. A highly parametric 14 percent scale transparent model was used to simulate the MFVT propulsion system. The working medium was water. The mixing between the fan and core flow was studied using flow visualization for a variety of geometrical and flow parameters including three bypass ratio variations. The flow visualization technique involves the use of laser light sheet for illumination and fluorescent dye or air bubbles as tracers. Results indicate the existence of a strong vortex flowfield in the hover mode of operation that is responsible for good mixing between the fan and core flows.

  17. Studies of fluid instabilities in flows of lava and debris

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan H.

    1987-01-01

    At least two instabilities have been identified and utilized in lava flow studies: surface folding and gravity instability. Both lead to the development of regularly spaced structures on the surfaces of lava flows. The geometry of surface folds have been used to estimate the rheology of lava flows on other planets. One investigation's analysis assumed that lava flows have a temperature-dependent Newtonian rheology, and that the lava's viscosity decreased exponentially inward from the upper surface. The author reviews studies by other investigators on the analysis of surface folding, the analysis of Taylor instability in lava flows, and the effect of surface folding on debris flows.

  18. Applications of GARCH models to energy commodities

    NASA Astrophysics Data System (ADS)

    Humphreys, H. Brett

    This thesis uses GARCH methods to examine different aspects of the energy markets. The first part of the thesis examines seasonality in the variance. This study modifies the standard univariate GARCH models to test for seasonal components in both the constant and the persistence in natural gas, heating oil and soybeans. These commodities exhibit seasonal price movements and, therefore, may exhibit seasonal variances. In addition, the heating oil model is tested for a structural change in variance during the Gulf War. The results indicate the presence of an annual seasonal component in the persistence for all commodities. Out-of-sample volatility forecasting for natural gas outperforms standard forecasts. The second part of this thesis uses a multivariate GARCH model to examine volatility spillovers within the crude oil forward curve and between the London and New York crude oil futures markets. Using these results the effect of spillovers on dynamic hedging is examined. In addition, this research examines cointegration within the oil markets using investable returns rather than fixed prices. The results indicate the presence of strong volatility spillovers between both markets, weak spillovers from the front of the forward curve to the rest of the curve, and cointegration between the long term oil price on the two markets. The spillover dynamic hedge models lead to a marginal benefit in terms of variance reduction, but a substantial decrease in the variability of the dynamic hedge; thereby decreasing the transactions costs associated with the hedge. The final portion of the thesis uses portfolio theory to demonstrate how the energy mix consumed in the United States could be chosen given a national goal to reduce the risks to the domestic macroeconomy of unanticipated energy price shocks. An efficient portfolio frontier of U.S. energy consumption is constructed using a covariance matrix estimated with GARCH models. The results indicate that while the electric

  19. Retail food commodity intakes: Mean amounts of retail commodities per individual, 1994-1998

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The table set includes national estimates of the amounts of retail-level commodities per person estimated from day 1 dietary intake data of 19,017 individuals, ages 2 years and over, in the Continuing Survey of Food Intakes by Individuals 1994-1998 and Food Intakes Converted to Retail Commodities Da...

  20. Retail food commodity intakes: Mean amounts of retail commodities per individual, 1999-2000

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Table sets of national estimates of the amounts of retail commodities per person were estimated from day 1 dietary intake data of 8,074 individuals, ages 2 years and over, in the National Health and Nutrition Examination Survey 1999-2000 using the Food Intakes Converted to Retail Commodities Databas...

  1. 49 CFR 1248.100 - Commodity classification designated.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... STATISTICS Commodity Code § 1248.100 Commodity classification designated. Commencing with reports for the..., reports of commodity statistics required to be made to the Board, shall be based on the commodity codes... Statistics, 1963, issued by the Bureau of the Budget, and on additional codes 411 through 462 shown in §...

  2. 22 CFR 201.63 - Maximum prices for commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Maximum prices for commodities. 201.63 Section... COMMODITY TRANSACTIONS FINANCED BY USAID Price Provisions § 201.63 Maximum prices for commodities. (a) U.S. prevailing market price—U.S. source. The purchase price for a commodity, the source of which is the...

  3. 7 CFR 868.32 - Who shall inspect commodities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Who shall inspect commodities. 868.32 Section 868.32... FOR CERTAIN AGRICULTURAL COMMODITIES Regulations Inspection Methods and Procedures § 868.32 Who shall inspect commodities. Official commodity inspections shall be performed only by official personnel....

  4. 41 CFR 51-6.13 - Replacement and similar commodities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... commodities. 51-6.13 Section 51-6.13 Public Contracts and Property Management Other Provisions Relating to... PROCEDURES § 51-6.13 Replacement and similar commodities. (a) When a commodity on the Procurement List is replaced by another commodity which has not been recently procured, and a nonprofit agency can furnish...

  5. 17 CFR 14.4 - Violation of Commodity Exchange Act.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Violation of Commodity Exchange Act. 14.4 Section 14.4 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION RULES RELATING TO SUSPENSION OR DISBARMENT FROM APPEARANCE AND PRACTICE § 14.4 Violation of...

  6. 49 CFR 1248.100 - Commodity classification designated.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... STATISTICS Commodity Code § 1248.100 Commodity classification designated. Commencing with reports for the..., reports of commodity statistics required to be made to the Board, shall be based on the commodity codes... Statistics, 1963, issued by the Bureau of the Budget, and on additional codes 411 through 462 shown in §...

  7. 49 CFR 1248.101 - Commodity codes required.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Commodity codes required. 1248.101 Section 1248.101 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION (CONTINUED) ACCOUNTS, RECORDS AND REPORTS FREIGHT COMMODITY STATISTICS Commodity Code § 1248.101 Commodity...

  8. 17 CFR 20.11 - Diversified commodity indices.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Diversified commodity indices... TRADER REPORTING FOR PHYSICAL COMMODITY SWAPS § 20.11 Diversified commodity indices. For the purpose of... commonly known diversified indices with publicly available weightings may be reported as if such...

  9. 17 CFR 20.11 - Diversified commodity indices.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 1 2012-04-01 2012-04-01 false Diversified commodity indices... TRADER REPORTING FOR PHYSICAL COMMODITY SWAPS § 20.11 Diversified commodity indices. For the purpose of... commonly known diversified indices with publicly available weightings may be reported as if such...

  10. 17 CFR 20.11 - Diversified commodity indices.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Diversified commodity indices... TRADER REPORTING FOR PHYSICAL COMMODITY SWAPS § 20.11 Diversified commodity indices. For the purpose of... commonly known diversified indices with publicly available weightings may be reported as if such...

  11. Experimental study of time-dependent flows in laboratory atmospheric flow models

    NASA Technical Reports Server (NTRS)

    Rush, J. E.

    1982-01-01

    Baroclinic waves in a rotating, differentially-heated annulus of liquid were studied in support of the Atmospheric General Circulation Experiment. Specific objectives were to determine: (1) the nature of the flow at shallow depths, (2) the effect of a rigid lid vs. free surface, and (3) the nature of fluctuations in the waves as a function of rotation rate, depth, and type of surface. It is found that flows with a rigid lid are basically the same as those with a free surface, except for a decrease in flow rate. At shallow depths steady flows are found in essentially the same form, but the incidence of unsteady flows is greatly diminished.

  12. Basic studies of microstructure of combusting turbulent flows

    NASA Astrophysics Data System (ADS)

    Hussain, Fazle

    1991-03-01

    The goal is to develop a state-of-the-art measurement technique, Holographic Particle Displacement Velocimetry (HPV), which can provide instantaneous velocities everywhere in the flow field simultaneously. Another goal is to use the power of supercomputers to simulate 3D flows with heat release to study the physics of combusting turbulent flows. Computations suffer from limited flow times and Reynolds number but can provide flow properties in more detail than possible by any existing experimental techniques. Moreover, numerical simulations can provide quantities almost impossible to measure experimentally. This article discusses efforts to develop the holographic particle displacement velocimetry system and results of direct numerical numerical simulations of combusting flows.

  13. Ultrasonic flow imaging system: A feasibility study

    SciTech Connect

    Sheen, S.H.; Lawrence, W.P.; Chien, H.T.; Raptis, A.C.

    1991-09-01

    This report examines the feasibility and potential problems in developing a real-time ultrasonic flow imaging instrument for on-line monitoring of mixed-phased flows such as coal slurries. State-of-the-art ultrasonic imaging techniques are assessed for this application. Reflection and diffraction tomographies are proposed for further development, including image-reconstruction algorithms and parallel processing systems. A conventional ultrasonic C-scan technique is used to demonstrate the feasibility of imaging the particle motion in a solid/water flow. 13 refs., 11 figs.

  14. The normal mycoflora of commodities from Thailand. 2. Beans, rice, small grains and other commodities.

    PubMed

    Pitt, J I; Hocking, A D; Bhudhasamai, K; Miscamble, B F; Wheeler, K A; Tanboon-Ek, P

    1994-09-01

    Part of a comprehensive study of fungi occurring in commodities in Thailand, this paper reports results from 276 samples of mung beans, rice, sorghum and soybeans as well as other minor crops. Samples for major commodities were taken from farmers' stocks, middlemen and retail outlets, while those for minor crops were mostly from retail. Each sample was divided into two portions, one being examined in Bangkok and the second at North Ryde. Mycological examinations were carried out by direct plating after surface disinfection in chlorine. Media used were dichloran rose bengal chloramphenicol agar, dichloran 18% glycerol agar, Aspergillus flavus and parasiticus agar and dichloran chloramphenicol peptone agar. Fungi were identified to species level and percentage infection of samples calculated. The dominant fungus found in mung beans was Fusarium semitectum, which was present in 40% of samples and at a high level (18% of all seeds) overall. Aspergillus flavus was also found in 40% of samples, but only in 2% of seeds overall. Lasiodiplodia theobromae was the only other fungus exceeding 1% total infection. The major fungi found in soybeans were A. flavus (67% of samples; 6% overall) and Cladosporium cladosporioides (49% of samples; 9% overall). Storage fungi were more common in soybeans than the other commodities, indicating longer or adverse storage. Paddy rice contained high levels of a wide variety of field fungi, notably Fusarium semitectum, Bipolaris oryzae, and Curvularia, Phoma and Colletotrichum species. However, probably due to the heat generated by milling, milled rice contained very few fungi, which were mostly of storage origin. Only 3% of particles examined contained internal fungi. Infection in sorghum was typical of oilseeds, dominated by Aspergillus flavus, which was present in 86% of samples, with an overall infection rate of 12%. Beans other than soybeans were infected by a wide range of field fungi, but at low levels, with less than half of seeds

  15. 17 CFR 4.41 - Advertising by commodity pool operators, commodity trading advisors, and the principals thereof.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Advertising by commodity pool operators, commodity trading advisors, and the principals thereof. 4.41 Section 4.41 Commodity and... advertise in a manner which: (1) Employs any device, scheme or artifice to defraud any participant or...

  16. Two-phase flow studies. Final report

    SciTech Connect

    Kestin, J.; Maeder, P.F.

    1980-08-01

    Progress on the following is reported: literature survey, design of two-phase flow testing facility, design of nozzle loop, thermophysical properties, design manual, and advanced energy conversion systems. (MHR)

  17. Prospects of Elliptic Flow Studies at NICA/MPD

    NASA Astrophysics Data System (ADS)

    Geraksiev, Nikolay

    2016-01-01

    As a key observable, anisotropic flow presents a unique insight into heavy ion collision physics. The presented poster reveals the prospects of studying elliptic flow at the NICA/MPD facility through the UrQMD model. Here, results for the elliptic flow of simulated and reconstructed hadrons at the planned NICA energy range are presented.

  18. The art and science of flow control - case studies using flow visualization methods

    NASA Astrophysics Data System (ADS)

    Alvi, F. S.; Cattafesta, L. N., III

    2010-04-01

    Active flow control (AFC) has been the focus of significant research in the last decade. This is mainly due to the potentially substantial benefits it affords. AFC applications range from the subsonic to the supersonic (and beyond) regime for both internal and external flows. These applications are wide and varied, such as controlling flow transition and separation over various external components of the aircraft to active management of separation and flow distortion in engine components and over turbine and compressor blades. High-speed AFC applications include control of flow oscillations in cavity flows, supersonic jet screech, impinging jets, and jet-noise control. In this paper we review some of our recent applications of AFC through a number of case studies that illustrate the typical benefits as well as limitations of present AFC methods. The case studies include subsonic and supersonic canonical flowfields such as separation control over airfoils, control of supersonic cavity flows and impinging jets. In addition, properties of zero-net mass-flux (ZNMF) actuators are also discussed as they represent one of the most widely studied actuators used for AFC. In keeping with the theme of this special issue, the flowfield properties and their response to actuation are examined through the use of various qualitative and quantitative flow visualization methods, such as smoke, shadowgraph, schlieren, planar-laser scattering, and Particle image velocimetry (PIV). The results presented here clearly illustrate the merits of using flow visualization to gain significant insight into the flow and its response to AFC.

  19. Numerical study of transient flow phenomena in shock tunnels

    NASA Technical Reports Server (NTRS)

    Tokarcik-Polsky, Susan; Cambier, Jean-Luc

    1994-01-01

    Computational fluid dynamics (CFD) was used to study some transient flow features that can occur during the startup process of a shoch tunnel. The investigation concentrated on two areas: (1) the flow near the endwall of the driven tube during shock reflection and (2) the transient flow in the nozzle. The driven tube calculations were inviscid and focused on the study of a vortex system that was seen to form at the driven tube's axis of symmetry. The nozzle flow calculations examined viscous and inviscid effects during nozzle startup. The CFD solutions of the nozzle flows were compared with experimental data to demonstrate the effectiveness of the numerical analysis.

  20. Acceptance of two US Department of Agriculture commodity whole-grain products: a school-based study in Texas and Minnesota.

    PubMed

    Chu, Yen Li; Warren, Cynthia A; Sceets, Christine E; Murano, Peter; Marquart, Len; Reicks, Marla

    2011-09-01

    Whole-grain intake among children and adolescents is below national recommendations, prompting efforts to increase intake in schools. The purpose of this study was to compare the acceptance of whole-grain pancakes and tortillas to refined grain counterparts when served as part of the school meal. Data were collected at 10 schools in Minnesota and seven schools in Texas during the Spring and Fall semesters of 2009. Three pancake and two tortilla products of varying red or white whole-wheat flour content were each served an average of four times per school. Aggregate plate waste was collected and percent consumption used to assess acceptance. Students rated each product on overall liking, taste, color, and softness on 5-point (elementary schools) or 9-point hedonic scales (middle and high schools). Analysis of covariance was used to compare intake and rating scores of all products. For all children, intake of whole-grain products was substantial (percent consumption ranging from 67% to 75%). No differences were noted in consumption of whole-wheat pancakes compared to refined wheat pancakes, while consumption of whole-wheat tortillas was lower than refined products. In elementary schools, overall liking scores of pancakes made with red whole-wheat and both types of whole-wheat tortillas were lower than refined products. However, in middle and high schools, overall liking scores of 100% red whole-wheat pancakes and 66% white whole-wheat tortillas were similar to refined products. Substituting refined grain with whole-grain options represents a viable approach to increasing consumption of whole-grain products in schools. PMID:21872702

  1. Integrated Electrochemical Processes for CO2 Capture and Conversion to Commodity Chemicals

    SciTech Connect

    Hatton, T. Alan; Jamison, Timothy

    2013-09-30

    The Massachusetts Institute of Technology (MIT) and Siemens Corporations (SCR) are developing new chemical synthesis processes for commodity chemicals from CO2. The process is assessed as a novel chemical sequestration technology that utilizes CO2 from dilute gas streams generated at industrial carbon emitters as a raw material to produce useful commodity chemicals. Work at Massachusetts Institute of Technology (MIT) commenced on October 1st, 2010, and finished on September 30th, 2013. During this period, we have investigated and accomplished five objectives that mainly focused on converting CO2 into high-value chemicals: 1) Electrochemical assessment of catalytic transformation of CO2 and epoxides to cyclic carbonates; 2) Investigation of organocatalytic routes to convert CO2 and epoxide to cyclic carbonates; 3) Investigation of CO2 Capture and conversion using simple olefins under continuous flow; 4) Microwave assisted synthesis of cyclic carbonates from olefins using sodium bicarbonates in a green pathway; 5) Life cycle analyses of integrated chemical sequestration process. In this final report, we will describe the detailed study performed during the three year period and findings and conclusions drawn from our research.

  2. CFD Validation Studies for Hypersonic Flow Prediction

    NASA Technical Reports Server (NTRS)

    Gnoffo, Peter A.

    2001-01-01

    A series of experiments to measure pressure and heating for code validation involving hypersonic, laminar, separated flows was conducted at the Calspan-University at Buffalo Research Center (CUBRC) in the Large Energy National Shock (LENS) tunnel. The experimental data serves as a focus for a code validation session but are not available to the authors until the conclusion of this session. The first set of experiments considered here involve Mach 9.5 and Mach 11.3 N, flow over a hollow cylinder-flare with 30 deg flare angle at several Reynolds numbers sustaining laminar, separated flow. Truncated and extended flare configurations are considered. The second set of experiments, at similar conditions, involves flow over a sharp, double cone with fore-cone angle of 25 deg and aft-cone angle of 55 deg. Both sets of experiments involve 30 deg compressions. Location of the separation point in the numerical simulation is extremely sensitive to the level of grid refinement in the numerical predictions. The numerical simulations also show a significant influence of Reynolds number on extent of separation. Flow unsteadiness was easily introduced into the double cone simulations using aggressive relaxation parameters that normally promote convergence.

  3. CFD Validation Studies for Hypersonic Flow Prediction

    NASA Technical Reports Server (NTRS)

    Gnoffo, Peter A.

    2001-01-01

    A series of experiments to measure pressure and heating for code validation involving hypersonic, laminar, separated flows was conducted at the Calspan-University at Buffalo Research Center (CUBRC) in the Large Energy National Shock (LENS) tunnel. The experimental data serves as a focus for a code validation session but are not available to the authors until the conclusion of this session. The first set of experiments considered here involve Mach 9.5 and Mach 11.3 N2 flow over a hollow cylinder-flare with 30 degree flare angle at several Reynolds numbers sustaining laminar, separated flow. Truncated and extended flare configurations are considered. The second set of experiments, at similar conditions, involves flow over a sharp, double cone with fore-cone angle of 25 degrees and aft-cone angle of 55 degrees. Both sets of experiments involve 30 degree compressions. Location of the separation point in the numerical simulation is extremely sensitive to the level of grid refinement in the numerical predictions. The numerical simulations also show a significant influence of Reynolds number on extent of separation. Flow unsteadiness was easily introduced into the double cone simulations using aggressive relaxation parameters that normally promote convergence.

  4. Large eddy simulation study of spanwise spacing effects on secondary flows in turbulent channel flow

    NASA Astrophysics Data System (ADS)

    Aliakbarimiyanmahaleh, Mohammad; Anderson, William

    2015-11-01

    The structure of turbulent flow over a complex topography composed of streamwise-aligned rows of cones with varying spanwise spacing, s is studied with large-eddy simulation (LES). Similar to the experimental study of Vanderwel and Ganapathisubramani, 2015: J. Fluid Mech., we investigate the relationship between secondary flow and s, for 0 . 25 <= s / δ <= 5 . For cases with s / δ > 2 , domain-scale rollers freely exist. These had previously been called ``turbulent secondary flows'' (Willingham et al., 2014: Phys. Fluids; Barros and Christensen, 2014: J. Fluid Mech.; Anderson et al., 2015: J. Fluid Mech.), but closer inspection of the statistics indicates these are a turbulent tertiary flow: they only remain ``anchored'' to the conical roughness elements for s / δ > 2 . For s / δ < 2 , turbulent tertiary flows are prevented from occupying the domain by virtue of proximity to adjacent, counter-rotating tertiary flows. Turbulent secondary flows are associated with the conical roughness elements. These turbulent secondary flows emanate from individual conical topographic elements and set the roughness sublayer depth. The turbulent secondary flows remain intact for large and small spacing. For s / δ < 1 , a mean tertiary flow is not present. This work was supported by the Air Force Office of Sci. Research, Young Inv. Program (PM: Dr. R. Ponnoppan and Ms. E. Montomery) under Grant # FA9550-14-1-0394. Computational resources were provided by the Texas Adv. Comp. Center at the Univ. of Texas.

  5. 76 FR 41048 - Agricultural Commodity Definition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-13

    ... FR 65586, Oct. 26, 2010. \\5\\ Those comments are available on the Commission's Web site at: http... to the term agricultural commodity, please review the NPRM at 75 FR 65586-65587. 2. The Dodd-Frank..., please review the NPRM at 75 FR 65588-65589. Under current regulations, the term agricultural...

  6. 75 FR 65586 - Agricultural Commodity Definition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... more commodities.'' (See 72 FR 66099, note 7 (November 27, 2007)). See new CEA Sec. 1a(47) for the... 58 FR 5587 (Jan. 22, 1993). Note that because Part 35 was implemented pursuant to a Sec. 4(c... Associated Property To Be Commingled With Other Property Held in Segregated Accounts, 73 FR 77015 (Dec....

  7. Commodities Trading: An Essential Economic Tool.

    ERIC Educational Resources Information Center

    Welch, Mary A., Ed.

    1989-01-01

    This issue focuses on commodities trading as an essential economic tool. Activities include critical thinking about marketing decisions and discussion on how futures markets and options are used as important economic tools. Discussion questions and a special student project are included. (EH)

  8. 49 CFR 173.167 - Consumer commodities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Consumer commodities. 173.167 Section 173.167 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Non-bulk...

  9. 48 CFR 8.715 - Replacement commodities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Replacement commodities. 8.715 Section 8.715 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition From Nonprofit Agencies Employing People...

  10. Coffee: The Most Teachable Commodity?

    ERIC Educational Resources Information Center

    Kenworthy, Eldon; Schaeffer, Eric

    2000-01-01

    Discusses one result of globalization that more of what people consume comes from distant regions through complex transitions hidden from ordinary view. Outlines the advantages of studying the coffee chain to understand its relationship to consumer choice and environmental issues. (Author/ASK)

  11. TANK MIXING STUDY WITH FLOW RECIRCULATION

    SciTech Connect

    Lee, S.

    2014-06-25

    The primary objective of this work is to quantify the mixing time when two miscible fluids are mixed by one recirculation pump and to evaluate adequacy of 2.5 hours of pump recirculation to be considered well mixed in SRS tanks, JT-71/72. The work scope described here consists of two modeling analyses. They are the steady state flow pattern analysis during pump recirculation operation of the tank liquid and transient species transport calculations based on the initial steady state flow patterns. The modeling calculations for the mixing time are performed by using the 99% homogeneity criterion for the entire domain of the tank contents.

  12. Numerical studies of 2-dimensional flows

    NASA Technical Reports Server (NTRS)

    Moretti, G.

    1985-01-01

    A formulation of the lambda scheme for the analysis of two dimensional inviscid, compressible, unsteady transonic flows is presented. The scheme uses generalized Riemann variables to determine the appropriate two point, one sided finite difference approximation for each derivative in the unsteady Euler equations. These finite differences are applied at the predictor and corrector levels with shock updating at each level. The weaker oblique shocks are captured, but strong near normal shocks are fitted into the flow using the Rankine-Hugoniot relations. This code is demonstrated with a numerical example of a duct flow problem with developing normal and oblique shock waves. The technique is implemented in a code which has been made efficient by streamlining to a minimal number of operations and by eliminating branch statements. The scheme is shown to provide an accurate analysis of the flow, including formation, motions, and interactions of shocks; the results obtained on a relatively coarse mesh are comparable to those obtained by other methods on much finer meshes.

  13. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study.

    PubMed

    Pennell, Thomas; Yi, Juneyoung L; Kaufman, Bruce A; Krishnamurthy, Satish

    2016-03-01

    OBJECT Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure CSF flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data. To address these needs, this preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drains (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor's capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor's ability to identify these changes. METHODS A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient's neurological status and their time points were noted. RESULTS The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow. CONCLUSIONS The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml

  14. An experimental study of flow around submerged grass vegetation

    NASA Astrophysics Data System (ADS)

    Lee, Julia; Mandre, Shreyas; Singh, Ravi

    2014-11-01

    Mixing of fluids through submerged vegetation caused by tidal currents facilitate various environmental and ecological transport processes. This fluid-vegetation interaction is believed to result from a Kelvin-Helmholtz instability from an inflection point in the flow profile. Recent studies suggest that flow in presence of grass can also become unstable due to shear instability of flow above the grass. We devise a two-dimensional lab scale analog of the fluid-vegetation interaction using ABS plastic filaments immersed in a soap film. We employ PIV of the surrounding flow to gain an understanding of the role of instabilities in the flow.

  15. Ex-situ experimental studies on serpentine flow field design for redox flow battery systems

    NASA Astrophysics Data System (ADS)

    Jyothi Latha, T.; Jayanti, S.

    2014-02-01

    Electrolyte distribution using parallel flow field for redox flow battery (RFB) applications shows severe non-uniformity, while the conventional design of using the carbon felt itself as the flow distributor gives too high pressure drop. An optimized flow field design for uniform flow distribution at a minimal parasitic power loss is therefore needed for RFB systems. Since the materials and geometrical dimensions in RFBs are very different from those used in fuel cells, the hydrodynamics of the flow fields in RFBs is likely to be very different. In the present paper, we report on a fundamental study of the hydrodynamics of a serpentine flow field relevant to RFB applications. The permeability of the porous medium has been measured under different compression ratios and this is found to be in the range of 5-8 × 10-11 m2. The pressure drop in two serpentine flow fields of different geometric characteristics has been measured over a range of Reynolds numbers. Further analysis using computational fluid dynamics simulations brings out the importance of the compression of the porous medium as an additional parameter in determining the flow distribution and pressure drop in these flow fields.

  16. Theoretical and experimental study of flow through turbine cascades with coolant flow injection

    NASA Technical Reports Server (NTRS)

    Tabakoff, W.; Hamed, A.

    1975-01-01

    An analytical study is presented which deals with the change in the outlet flow conditions from a turbine blade row due to coolant air injection through slots. The analysis applies to small secondary to primary mass flow ratios, taking into consideration the change in boundary layer development resulting from injection. The effects of injection location, injection flow angle and injected air momentum flux are investigated. The results of the present analysis are compared with the values obtained using the mixing theory method and experimental data from cold flow tests in a turbine cascade tunnel.

  17. Study on turbulence in interior ballistics flows

    NASA Astrophysics Data System (ADS)

    Heiser, R.; Garloff, J.

    1992-02-01

    The compressible, viscous, turbulent gas expansion flow behind an accelerating projectile moving in a gun tube is investigated by solving the Navier-Stokes equations. For future theoretical investigations of the heat transfer from the hot gases to the walls, a reliable modeling of the turbulence is needed. Turbulence is described by two algebraic models, namely, the models by Cebeci-Smith-Mosinskis and Baldwin-Lomax, as well as by a one-equation model for the turbulent kinetic energy. Computational results obtained by application of these models are compared to experimental data obtained with two low-pressure gun simulators. Also, numerical predictions are reported for the flow behind a projectile under more realistic interior ballistic conditions.

  18. NMR studies of multiphase flows II

    SciTech Connect

    Altobelli, S.A.; Caprihan, A.; Fukushima, E.

    1995-12-31

    NMR techniques for measurements of spatial distribution of material phase, velocity and velocity fluctuation are being developed and refined. Versions of these techniques which provide time average liquid fraction and fluid phase velocity have been applied to several concentrated suspension systems which will not be discussed extensively here. Technical developments required to further extend the use of NMR to the multi-phase flow arena and to provide measurements of previously unobtainable parameters are the focus of this report.

  19. Online recognition of the multiphase flow regime and study of slug flow in pipeline

    NASA Astrophysics Data System (ADS)

    Liejin, Guo; Bofeng, Bai; Liang, Zhao; Xin, Wang; Hanyang, Gu

    2009-02-01

    single sensor performance. Among various flow patterns of gas-liquid flow, slug flow occurs frequently in the petroleum, chemical, civil and nuclear industries. In the offshore oil and gas field, the maximum slug length and its statistical distribution are very important for the design of separator and downstream processing facility at steady state operations. However transient conditions may be encountered in the production, such as operational upsets, start-up, shut-down, pigging and blowdown, which are key operational and safety issues related to oil field development. So it is necessary to have an understanding the flow parameters under transient conditions. In this paper, the evolution of slug length along a horizontal pipe in gas-liquid flow is also studied in details and then an experimental study of flowrate transients in slug flow is provided. Also, the special gas-liquid flow phenomena easily encountered in the life span of offshore oil fields, called severe slugging, is studied experimentally and some results are presented.

  20. The Principles and the Specifics of Trading in Commodities

    NASA Astrophysics Data System (ADS)

    Baran, Dušan; Herbacsková, Anita

    2012-12-01

    In the present period of instability on financial markets, investments in commodities are the solution for elimination of the consequences of inflation and ensure the yield. When investing in commodities, the use of specifics of commodities compared to other assets. The distribution of commodities we can interpret for agricultural commodities, commodities of energy, precious and other metals, and weather. Therefore, in the framework of the investment portfolio are the commodities. This is the reason why one of the most popular types of investment assets now become commodities. In the interpretation of particular commodities we talk about commodity futures. The reason is that the spot market with commodities is limited storage facilities. The growth of the popularity, which allows a wide range of commodities, has caused that in addition to from institutional investors and speculators for trade may involve even small investors. This development will be supplemented by interpretation of the charts and figers, which will be commented and used for generalization of knowledge. Finally, the article will be interpreted by the further development of the market for commodities as it by article assumes from the results of research.

  1. Validation studies for brain blood flow assessment by radioxenon tomography

    SciTech Connect

    Rezai, K.; Kirchner, P.T.; Armstrong, C.; Ehrhardt, J.C.; Heistad, D.

    1988-03-01

    A tomographic technique has been used recently for cerebral blood flow measurements with inhaled radioxenon. Based on experiments in a specially developed dynamic phantom and on studies in primates in vivo, we have analyzed the validity of this method for measurements of both regional and total blood flow in the brain. We have also examined the errors introduced into flow computations as a function of changes in such parameters as: rate of xenon input, size of region of interest, magnitude of regional flow rates, and inter-regional flow differences. Our findings indicate a reasonable degree of accuracy for flow measurements in gray matter regions that are 3 cm in diameter or larger, while white matter blood flow is generally overestimated. The accuracy for regional flow assessments degrades as a function of: diminishing region size, increasing inter-regional flow differences, and flow rates in excess of 100 ml/100 g/min. Measurements for brain regions 2 cm or smaller in diameter can be in error by 25-50% as a result of partial volume averaging. Although the technique is not ideal for accurate flow measurements in small regions of the brain, it nevertheless provides a convenient means of assessing perfusion in major vascular territories of the brain in routine clinical applications.

  2. International Trade Modelling Using Open Flow Networks: A Flow-Distance Based Analysis

    PubMed Central

    Shen, Bin; Zhang, Jiang; Li, Yixiao; Zheng, Qiuhua; Li, Xingsen

    2015-01-01

    This paper models and analyzes international trade flows using open flow networks (OFNs) with the approaches of flow distances, which provide a novel perspective and effective tools for the study of international trade. We discuss the establishment of OFNs of international trade from two coupled viewpoints: the viewpoint of trading commodity flow and that of money flow. Based on the novel model with flow distance approaches, meaningful insights are gained. First, by introducing the concepts of trade trophic levels and niches, countries’ roles and positions in the global supply chains (or value-added chains) can be evaluated quantitatively. We find that the distributions of trading “trophic levels” have the similar clustering pattern for different types of commodities, and summarize some regularities between money flow and commodity flow viewpoints. Second, we find that active and competitive countries trade a wide spectrum of products, while inactive and underdeveloped countries trade a limited variety of products. Besides, some abnormal countries import many types of goods, which the vast majority of countries do not need to import. Third, harmonic node centrality is proposed and we find the phenomenon of centrality stratification. All the results illustrate the usefulness of the model of OFNs with its network approaches for investigating international trade flows. PMID:26569618

  3. International Trade Modelling Using Open Flow Networks: A Flow-Distance Based Analysis.

    PubMed

    Shen, Bin; Zhang, Jiang; Li, Yixiao; Zheng, Qiuhua; Li, Xingsen

    2015-01-01

    This paper models and analyzes international trade flows using open flow networks (OFNs) with the approaches of flow distances, which provide a novel perspective and effective tools for the study of international trade. We discuss the establishment of OFNs of international trade from two coupled viewpoints: the viewpoint of trading commodity flow and that of money flow. Based on the novel model with flow distance approaches, meaningful insights are gained. First, by introducing the concepts of trade trophic levels and niches, countries' roles and positions in the global supply chains (or value-added chains) can be evaluated quantitatively. We find that the distributions of trading "trophic levels" have the similar clustering pattern for different types of commodities, and summarize some regularities between money flow and commodity flow viewpoints. Second, we find that active and competitive countries trade a wide spectrum of products, while inactive and underdeveloped countries trade a limited variety of products. Besides, some abnormal countries import many types of goods, which the vast majority of countries do not need to import. Third, harmonic node centrality is proposed and we find the phenomenon of centrality stratification. All the results illustrate the usefulness of the model of OFNs with its network approaches for investigating international trade flows. PMID:26569618

  4. Valuing embryos as both commodities and singularities.

    PubMed

    Legge, Michael; Fitzgerald, Ruth

    2016-03-11

    An argument put forward against gamete and embryo donation, sale and research, is that to do so would treat the gametes or embryos as objects with no intrinsic value as human. Instead, gametes and embryos created and used for donation, sale or research, can be considered more like a commodity created and traded for economic exchange--something that is valuable only for the amount of money or other goods and services that others are willing to exchange. While Kant asserts that humans have dignity rather than object worth, the provision of human gametes and embryos are progressively becoming utilities for resolving childlessness and for certain research investigations. In this paper we discuss the commodity market and the relationship to human reproduction material. PMID:27005877

  5. Asymmetric energy flow in liquid alkylbenzenes: A computational study

    SciTech Connect

    Leitner, David M.; Pandey, Hari Datt

    2015-10-14

    Ultrafast IR-Raman experiments on substituted benzenes [B. C. Pein et al., J. Phys. Chem. B 117, 10898–10904 (2013)] reveal that energy can flow more efficiently in one direction along a molecule than in others. We carry out a computational study of energy flow in the three alkyl benzenes, toluene, isopropylbenzene, and t-butylbenzene, studied in these experiments, and find an asymmetry in the flow of vibrational energy between the two chemical groups of the molecule due to quantum mechanical vibrational relaxation bottlenecks, which give rise to a preferred direction of energy flow. We compare energy flow computed for all modes of the three alkylbenzenes over the relaxation time into the liquid with energy flow through the subset of modes monitored in the time-resolved Raman experiments and find qualitatively similar results when using the subset compared to all the modes.

  6. Computational studies of lobed forced mixer flows

    NASA Astrophysics Data System (ADS)

    Hu, H.; Wu, S. S.; Yu, S. C. M.

    1998-03-01

    Full Navier-Stokes Analyses have been conducted for the flows behind the trailing edge of a lobed forced mixer. The governing equations are derived from the time-dependent compressible Navier-Stokes equations and discretized in the finite-difference form. A simple two-layer eddy viscosity model has also been used to account for the turbulence. Computed results are compared with some of the velocity measurements using a laser-Doppler anemometer (Yu and Yip (1997)). In general, good agreement can be obtained in the streamwise mean velocity distribution but the decay of the streamwise circulation is underpredicted. Some suggestions to the discrepancy are proposed.

  7. Pricing commodity outpatient procedures assessing the impact.

    PubMed

    Cleverley, William O

    2015-10-01

    Hospitals should carefully consider all relevant factors before choosing to lower prices and payments for certain outpatient commodity services in an effort to remain competitive in their market. Key steps to take in the evaluation process include: Determining current profitability. Assessing profitability by payer class. Understanding overall cost positions. Assessing the relative payment terms of current commercial contracts. Determining the net revenue effect of proposed changes. PMID:26595979

  8. Studies in Transition and Time Varying Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Grosch, Chester E.

    2004-01-01

    The research focused on two areas: (a) the dynamics of forced turbulent flows and (b) time filtered Large Eddy Simulations (TLES). The dynamics of turbulent flows arising from external forcing of the turbulence are poorly understood. In particular, here are many unanswered questions relating the basic dynamical balances and the existence or nonexistence of statistical equilibrium of forced turbulent flows. The research used direct numerical simulations to explore these questions. The properties of the temporally filtered Navier-Stokes equations were also studied.

  9. Schlieren System For Flow Studies In Round Glass Pipes

    NASA Technical Reports Server (NTRS)

    Costen, Robert C.; Rhodes, David B.; Jones, Stephen B.

    1990-01-01

    In schlieren system for studying flow of gas in transparent pipe of circular cross section, cylindrical lenses placed on opposite sides of pipe compensate for refraction caused by wall of pipe. Enables direct visualization of such phenomena as laminar or turbulent flow, shock waves, vortexes, and flow separations in systems having inherently cylindrical geometry; potentially unreliable extrapolations from results in flat-sided test cells no longer necessary.

  10. Study of unsteady flow conditions for slurry fuels

    SciTech Connect

    Ekmann, J.M.; Wildman, D.J.; Klinzing, G.E.

    1985-01-01

    During the past three years, transport characteristics of coal-water mixtures (CWMs) have been studied at the Pittsburgh Energy Technology Center. The effort has concentrated predominantly on studying flow conditions in straight horizontal and vertical sections, and to a lesser extent on studying the flow patterns around elbows of a one-inch-diameter loop and a two-inch-diameter loop. Steady-state flow was characterized for in-house prepared slurries and commercially prepared slurries. For lower concentrated slurries (55 wt % to 60 wt %) and coarse particle size distributions (50% finer than 75 microns), nonhomogeneous flow conditions were encountered across horizontal test sections. Since nonhomogeneous conditions existed in straight sections during steady-state flow, it was decided to further investigate flow conditions during changes in velocity (magnitude and direction). This paper concentrates on nonuniform flow conditions of two types. The first nonuniform flow condition arises from sudden increases in the magnitude of the flow velocity. Pressure measurements recorded at a fixed position in the vertical section of the two-inch-diameter loop during sudden changes in velocity can be analyzed via classic control theory to evaluate the dynamic properties of the CWM. The second nonuniform flow condition occurs as the CWM passes through a bend. Both long-radius bends and 90-degree elbows made of glass and steel have been studied. Pressure-loss data around the long-radius bends and elbows were analyzed with a modified version of the model developed by Ito for single-phase flow around bends. Flow patterns around glass bends and elbows were observed for slurries prepared of vinyl coating powder and water. They are described in an effort to increase understanding of the pressure-loss data. 8 refs., 11 figs., 1 tab.

  11. Incorporating agroforestry approaches into commodity value chains.

    PubMed

    Millard, Edward

    2011-08-01

    The productivity of tropical agricultural commodities is affected by the health of the ecosystem. Shade tolerant crops such as coffee and cocoa benefit from environmental services provided by forested landscapes, enabling landscape design that meets biodiversity conservation and economic needs. What can motivate farmers to apply and maintain such landscape approaches? Rather than rely on a proliferation of externally funded projects new opportunities are emerging through the international market that buys these commodities. As part of their growing commitment to sustainable supply chains, major companies are supporting agroforestry approaches and requiring producers and traders to demonstrate that the source of their commodities complies with a set of principles that conserves forested landscapes and improves local livelihoods. The paper presents examples of international companies that are moving in this direction, analyzes why and how they are doing it and discusses the impact that has been measured in coffee and cocoa communities in Latin America and Africa. It particularly considers the role of standards and certification systems as a driver of this commitment to promote profitable operations, environmental conservation and social responsibility throughout the coffee and cocoa value chains. Such approaches are already being taken to scale and are no longer operating only in small niches of the market but the paper also considers the limitations to growth in this market-based approach. PMID:21556936

  12. Incorporating Agroforestry Approaches into Commodity Value Chains

    NASA Astrophysics Data System (ADS)

    Millard, Edward

    2011-08-01

    The productivity of tropical agricultural commodities is affected by the health of the ecosystem. Shade tolerant crops such as coffee and cocoa benefit from environmental services provided by forested landscapes, enabling landscape design that meets biodiversity conservation and economic needs. What can motivate farmers to apply and maintain such landscape approaches? Rather than rely on a proliferation of externally funded projects new opportunities are emerging through the international market that buys these commodities. As part of their growing commitment to sustainable supply chains, major companies are supporting agroforestry approaches and requiring producers and traders to demonstrate that the source of their commodities complies with a set of principles that conserves forested landscapes and improves local livelihoods. The paper presents examples of international companies that are moving in this direction, analyzes why and how they are doing it and discusses the impact that has been measured in coffee and cocoa communities in Latin America and Africa. It particularly considers the role of standards and certification systems as a driver of this commitment to promote profitable operations, environmental conservation and social responsibility throughout the coffee and cocoa value chains. Such approaches are already being taken to scale and are no longer operating only in small niches of the market but the paper also considers the limitations to growth in this market-based approach.

  13. Endoscopic metrology for cardiovascular flows studies

    NASA Astrophysics Data System (ADS)

    Arévalo, Laura; Roche, Eva; Palero, Virginia; Andrés, Nieves; Lobera, Julia; Martínez, Miguel Ángel; Arroyo, M. Pilar

    2014-07-01

    The complete measurement of the blood velocity and the vein wall deformation is important in order to obtain the wall shear stress distribution in blood vessels. This information would facilitate the diagnosis and treatment of some cardiovascular diseases. In this work, endoscopy has been combined with high speed Particle Image Velocimetry (PIV) to obtain the flow velocity inside a transparent vessel model and with digital holography to measure the vessel wall deformation. The use of endoscopes presents different advantages: they allow the simultaneous illumination and imaging of the object under inspection; the endoscopes can be moved as close as required and can be located anywhere to observe different regions. They can be used for observing inside opaque vessels in an oblique way, where the image perspective distortion can be corrected numerically. High speed PIV and endoscopic PIV have been applied to evaluate the influence of an antithrombotic filter in the velocity field inside an inferior vena cava (IVC) model. Endoscopic digital holography has been developed to measure the wall deformation in vessel models with steady and pulsatile flows. The models present different flexibility and opacity grades. Both the vessel model and the endoscope end are immersed in a refractive index matching liquid in order to avoid distortions.

  14. Evaluation of uncertainties due to hydrogeological modeling and groundwater flow analysis: Steady flow, transient flow, and thermal studies

    SciTech Connect

    Doughty, Christine; Karasaki, Kenzi

    2002-12-11

    Starting with regional geographic, geologic, surface and subsurface hydrologic, and geophysical data for the Tono area in Gifu, Japan, we develop an effective continuum model to simulate subsurface flow and transport in a 4 km by 6 km by 3 km thick fractured granite rock mass overlain by sedimentary layers. Individual fractures are not modeled explicitly. Rather, continuum permeability and porosity distributions are assigned stochastically, based on well-test data and fracture density measurements. Lithologic layering and one major fault, the Tsukiyoshi Fault, are assigned deterministically. We conduct three different studies: (1) the so-called base case, in which the model simulates the steady-state groundwater flow through the site, and then stream trace analysis is used to calculate travel times to the model boundary from specified release points; (2) simulations of transient flow during long term pump tests (LTPT) using the base-case model; and (3) thermal studies in which coupled heat flow and fluid flow are modeled, to examine the effects of the geothermal gradient on groundwater flow. The base-case study indicates that the choice of open or closed lateral boundaries has a strong influence on the regional groundwater flow patterns produced by the models, but no field data exist that can be used to determine which boundary conditions are more realistic. The LTPT study cannot be used to distinguish between the alternative boundary conditions, because the pumping rate is too small to produce an analyzable pressure response at the model boundaries. In contrast, the thermal study shows that the temperature distributions produced by the open and closed models differ greatly. Comparison with borehole temperature data may be used to eliminate the closed model from further consideration.

  15. Computational flow study of the continuous flow ventricular assist device, prototype number 3 blood pump.

    PubMed

    Anderson, J B; Wood, H G; Allaire, P E; Bearnson, G; Khanwilkar, P

    2000-05-01

    A computational fluid dynamics study of blood flow in the continuous flow ventricular assist device, Prototype No. 3 (CFVAD3), which consists of a 4 blade shrouded impeller fully supported in magnetic bearings, was performed. This study focused on the regions within the pump where return flow occurs to the pump inlet, and where potentially damaging shear stresses and flow stagnation might occur: the impeller blade passages and the narrow gap clearance regions between the impeller-rotor and pump housing. Two separate geometry models define the spacing between the pump housing and the impeller's hub and shroud, and a third geometry model defines the pump's impeller and curved blades. The flow fields in these regions were calculated for various operating conditions of the pump. Pump performance curves were calculated, which compare well with experimentally obtained data. For all pump operating conditions, the flow rates within the gap regions were predicted to be toward the inlet of the pump, thus recirculating a portion of the impeller flow. Two smaller gap clearance regions were numerically examined to reduce the recirculation and to improve pump efficiency. The computational and geometry models will be used in future studies of a smaller pump to determine increased pump efficiency and the risk of hemolysis due to shear stress, and to insure the washing of blood through the clearance regions to prevent thrombosis. PMID:10848679

  16. 15 CFR 740.18 - Agricultural commodities (AGR).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... permits the export of agricultural commodities to Cuba, as well as the reexport of U.S. origin... EAR99. You must have an official commodity classification of EAR99 from BIS for fertilizers, western red... commodity containing more than 10% U.S.-origin content. Such U.S.-owned or controlled foreign firms...

  17. 49 CFR 1248.1 - Freight commodity statistics.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Freight commodity statistics. 1248.1 Section 1248... STATISTICS § 1248.1 Freight commodity statistics. All class I railroads, as described in § 1240.1 of this... statistics on the basis of the commodity codes named in § 1248.101. Carriers shall report quarterly on...

  18. 49 CFR 1248.1 - Freight commodity statistics.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 9 2012-10-01 2012-10-01 false Freight commodity statistics. 1248.1 Section 1248... STATISTICS § 1248.1 Freight commodity statistics. All class I railroads, as described in § 1240.1 of this... statistics on the basis of the commodity codes named in § 1248.101. Carriers shall report quarterly on...

  19. 49 CFR 1248.1 - Freight commodity statistics.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 9 2013-10-01 2013-10-01 false Freight commodity statistics. 1248.1 Section 1248... STATISTICS § 1248.1 Freight commodity statistics. All class I railroads, as described in § 1240.1 of this... statistics on the basis of the commodity codes named in § 1248.101. Carriers shall report quarterly on...

  20. Botswana's Beef Global Commodity Chain: Explaining the Resistance to Change

    ERIC Educational Resources Information Center

    Ransom, Elizabeth

    2011-01-01

    In an era of increasing global agricultural trade, many firms and farms seek to upgrade their agricultural commodity chains to become better integrated into global markets. Utilizing a global commodity chain (GCC) approach, this analysis unravels the challenges to and the potential consequences of upgrading Botswana's beef commodity chain.…

  1. 22 CFR 211.6 - Processing, repackaging, and labeling commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... commodities. 211.6 Section 211.6 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT TRANSFER OF FOOD COMMODITIES FOR FOOD USE IN DISASTER RELIEF, ECONOMIC DEVELOPMENT AND OTHER ASSISTANCE § 211.6 Processing..., with the following information in the language of the country in which the commodities are to...

  2. 22 CFR 211.4 - Availability and shipment of commodities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Availability and shipment of commodities. 211.4 Section 211.4 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT TRANSFER OF FOOD COMMODITIES FOR FOOD USE IN DISASTER RELIEF, ECONOMIC DEVELOPMENT AND OTHER ASSISTANCE § 211.4 Availability and shipment of commodities. (a) Shipment,...

  3. 7 CFR 1499.8 - Entry and handling of commodities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Entry and handling of commodities. 1499.8 Section 1499.8 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE EXPORT PROGRAMS FOOD FOR PROGRESS PROGRAM § 1499.8 Entry and handling of commodities. (a) The participant shall make...

  4. 7 CFR 1421.110 - Commodity certificate exchanges.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Commodity certificate exchanges. 1421.110 Section 1421.110 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT... COMMODITIES-MARKETING ASSISTANCE LOANS AND LOAN DEFICIENCY PAYMENTS FOR 2008 THROUGH 2012 Marketing...

  5. 7 CFR 1427.22 - Commodity certificate exchanges.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Commodity certificate exchanges. 1427.22 Section 1427.22 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION... Deficiency Payments § 1427.22 Commodity certificate exchanges. (a) For any outstanding marketing...

  6. 7 CFR 226.5 - Donation of commodities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Donation of commodities. 226.5 Section 226.5... of commodities. (a) USDA foods available under section 6 of this Act, section 416 of the Agricultural... the Department shall be made available to each State. (b) The value of such commodities donated...

  7. 7 CFR 46.39 - Inspection of commodities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Inspection of commodities. 46.39 Section 46.39..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE MARKETING OF PERISHABLE AGRICULTURAL COMMODITIES REGULATIONS (OTHER THAN RULES OF PRACTICE) UNDER THE PERISHABLE AGRICULTURAL COMMODITIES ACT, 1930...

  8. 49 CFR 1248.1 - Freight commodity statistics.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Freight commodity statistics. 1248.1 Section 1248... STATISTICS § 1248.1 Freight commodity statistics. All class I railroads, as described in § 1240.1 of this... statistics on the basis of the commodity codes named in § 1248.101. Carriers shall report quarterly on...

  9. 49 CFR 1248.1 - Freight commodity statistics.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Freight commodity statistics. 1248.1 Section 1248... STATISTICS § 1248.1 Freight commodity statistics. All class I railroads, as described in § 1240.1 of this... statistics on the basis of the commodity codes named in § 1248.101. Carriers shall report quarterly on...

  10. 22 CFR 201.31 - Suppliers of commodities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Suppliers of commodities. 201.31 Section 201.31 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE TO COMMODITY TRANSACTIONS FINANCED BY USAID Responsibilities of Suppliers § 201.31 Suppliers of commodities. (a) Performance of the sales contract. The...

  11. 17 CFR 37.3 - Requirements for underlying commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... facilities limited to eligible commercial entities. Any commodity, other than the agricultural commodities... 5a(b)(3) of the Act, may trade any contract of sale of a commodity for future delivery (or option on... the self-regulatory record and capacity of the facility, that trading in the contract (or...

  12. 22 CFR 201.31 - Suppliers of commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Suppliers of commodities. 201.31 Section 201.31 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE TO COMMODITY TRANSACTIONS FINANCED BY USAID Responsibilities of Suppliers § 201.31 Suppliers of commodities. (a) Performance of the sales contract. The...

  13. The Pilot Training Study: Personnel Flow and the PILOT Model.

    ERIC Educational Resources Information Center

    Mooz, W. E.

    The results of the Rand study of pilot flows and the computer-operated decision model, called the PILOT model, are described. The flows of pilots within the Air Force are caused by policies that require the career-development rotation of pilots from cockpit jobs to desk jobs, the maintenance of a supplement of pilots in excess of cockpit-related…

  14. Using Discrete Event Simulation to Model Integrated Commodities Consumption for a Launch Campaign of the Space Launch System

    NASA Technical Reports Server (NTRS)

    Leonard, Daniel; Parsons, Jeremy W.; Cates, Grant

    2014-01-01

    In May 2013, NASA's GSDO Program requested a study to develop a discrete event simulation (DES) model that analyzes the launch campaign process of the Space Launch System (SLS) from an integrated commodities perspective. The scope of the study includes launch countdown and scrub turnaround and focuses on four core launch commodities: hydrogen, oxygen, nitrogen, and helium. Previously, the commodities were only analyzed individually and deterministically for their launch support capability, but this study was the first to integrate them to examine the impact of their interactions on a launch campaign as well as the effects of process variability on commodity availability. The study produced a validated DES model with Rockwell Arena that showed that Kennedy Space Center's ground systems were capable of supporting a 48-hour scrub turnaround for the SLS. The model will be maintained and updated to provide commodity consumption analysis of future ground system and SLS configurations.

  15. Numerical Study of Unsteady Flow in Centrifugal Cold Compressor

    NASA Astrophysics Data System (ADS)

    Zhang, Ning; Zhang, Peng; Wu, Jihao; Li, Qing

    In helium refrigeration system, high-speed centrifugal cold compressor is utilized to pumped gaseous helium from saturated liquid helium tank at low temperature and low pressure for producing superfluid helium or sub-cooled helium. Stall and surge are common unsteady flow phenomena in centrifugal cold compressors which severely limit operation range and impact efficiency reliability. In order to obtain the installed range of cold compressor, unsteady flow in the case of low mass flow or high pressure ratio is investigated by the CFD. From the results of the numerical analysis, it can be deduced that the pressure ratio increases with the decrease in reduced mass flow. With the decrease of the reduced mass flow, backflow and vortex are intensified near the shroud of impeller. The unsteady flow will not only increase the flow loss, but also damage the compressor. It provided a numerical foundation of analyzing the effect of unsteady flow field and reducing the flow loss, and it is helpful for the further study and able to instruct the designing.

  16. Study of flow patterns in fume hood enclosures

    SciTech Connect

    Pathanjali, C.; Rahman, M.M.

    1996-12-31

    A three-dimensional model for flow inside a fume hood enclosure was developed and numerical computations were carried out to explore the flow pattern and possible path of contaminant transport under different operating conditions of the hood. Equations for the conservation of mass and momentum were solved for different flow rate and opening conditions in the hood. The face velocity was maintained constant at its rated value of 0.4 m/s. The flow was assumed to enter through the front window opening (positive x-direction) and leave the cupboard through an opening on the top of the hood (positive z-direction). The flow was assumed to be fully turbulent. The {kappa}-{var_epsilon} model was used for the prediction of turbulence. The flow pattern for different sash openings were studied. The flow patterns around an object located at the bottom of the hood was studied for different locations of the object. In addition, the effect of a person standing in front of the hood on the flow pattern was investigated. It was found that air entering the hood proceeds directly to the back wall, impinges it and turns upward toward the top wall and exits through the outlet. The flow finds its way around any object forming a recirculating region at its trailing surface. With an increase in the sash opening, the velocity becomes higher and the fluid traces the path to the outlet more quickly. The volume occupied by recirculating flow decreases with increase in sash opening. The computed flow patterns will be very useful to design experiments with optimum sash opening providing adequate disposal of contaminants with minimum use of conditioned air from inside the room.

  17. Experimental Studies of Low-Pressure Turbine Flows and Flow Control

    NASA Technical Reports Server (NTRS)

    Volino, Ralph J.

    2012-01-01

    This report summarizes research performed in support of the NASA Glenn Research Center (GRC) Low-Pressure Turbine (LPT) Flow Physics Program. The work was performed experimentally at the U.S. Naval Academy faculties. The geometry corresponded to "Pak B" LPT airfoil. The test section simulated LPT flow in a passage. Three experimental studies were performed: (a) Boundary layer measurements for ten baseline cases under high and low freestream turbulence conditions at five Reynolds numbers of 25,000, 50,000, 100,000, 200,000, and 300,000, based on passage exit velocity and suction surface wetted length; (b) Passive flow control studies with three thicknesses of two-dimensional bars, and two heights of three-dimensional circular cylinders with different spanwise separations, at same flow conditions as the 10 baseline cases; (c) Active flow control with oscillating synthetic (zero net mass flow) vortex generator jets, for one case with low freestream turbulence and a low Reynolds number of 25,000. The Passive flow control was successful at controlling the separation problem at low Reynolds numbers, with varying degrees of success from case to case and varying levels of impact at higher Reynolds numbers. The active flow control successfully eliminated the large separation problem for the low Reynolds number case. Very detailed data was acquired using hot-wire anemometry, including single and two velocity components, integral boundary layer quantities, turbulence statistics and spectra, turbulent shear stresses and their spectra, and intermittency, documenting transition, separation and reattachment. Models were constructed to correlate the results. The report includes a summary of the work performed and reprints of the publications describing the various studies.

  18. Some specific features of the NMR study of fluid flows

    NASA Astrophysics Data System (ADS)

    Davydov, V. V.

    2016-07-01

    Some specific features of studying fluid flows with a NMR spectrometer are considered. The consideration of these features in the NMR spectrometer design makes it possible to determine the relative concentrations of paramagnetic ions and measure the longitudinal and transverse relaxation times ( T 1 and T 2, respectively) in fluid flows with an error no larger than 0.5%. This approach allows one to completely avoid errors in determining the state of a fluid from measured relaxation constants T 1 and T 2, which is especially urgent when working with medical suspensions and biological solutions. The results of an experimental study of fluid flows are presented.

  19. Numerical studies of transverse curvature effects on transonic flow stability

    NASA Technical Reports Server (NTRS)

    Macaraeg, M. G.; Daudpota, Q. I.

    1992-01-01

    A numerical study of transverse curvature effects on compressible flow temporal stability for transonic to low supersonic Mach numbers is presented for axisymmetric modes. The mean flows studied include a similar boundary-layer profile and a nonsimilar axisymmetric boundary-layer solution. The effect of neglecting curvature in the mean flow produces only small quantitative changes in the disturbance growth rate. For transonic Mach numbers (1-1.4) and aerodynamically relevant Reynolds numbers (5000-10,000 based on displacement thickness), the maximum growth rate is found to increase with curvature - the maximum occurring at a nondimensional radius (based on displacement thickness) between 30 and 100.

  20. Knowledge-based commodity distribution planning

    NASA Technical Reports Server (NTRS)

    Saks, Victor; Johnson, Ivan

    1994-01-01

    This paper presents an overview of a Decision Support System (DSS) that incorporates Knowledge-Based (KB) and commercial off the shelf (COTS) technology components. The Knowledge-Based Logistics Planning Shell (KBLPS) is a state-of-the-art DSS with an interactive map-oriented graphics user interface and powerful underlying planning algorithms. KBLPS was designed and implemented to support skilled Army logisticians to prepare and evaluate logistics plans rapidly, in order to support corps-level battle scenarios. KBLPS represents a substantial advance in graphical interactive planning tools, with the inclusion of intelligent planning algorithms that provide a powerful adjunct to the planning skills of commodity distribution planners.

  1. Airships for transporting highly volatile commodities

    NASA Technical Reports Server (NTRS)

    Sonstegaard, M.

    1975-01-01

    Large airships may prove feasible as carriers of commodities that move as gases or cryogenic liquids; buoyant gaseous cargo could be ballasted with liquid cargo. Airships are compact in shape, operate in a rarified medium, and hence can be fast and perhaps economic carriers of costly cryogenic tanks. The high-pressure gas pipeline has excessive surface area when carrying hydrogen and excessive fluid density when carrying natural gas, while the cryogenic ocean tanker runs in a dense medium and makes gravity waves. But the airship, despite its fluid dynamic advantages, faces problems of safety, weather, and altitude control.

  2. Computational studies of flow through cross flow fans - effect of blade geometry

    NASA Astrophysics Data System (ADS)

    Govardhan, M.; Sampat, D. Lakshmana

    2005-09-01

    This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFD) software code CFX was used for the computation. RNG k-ɛ two equation turbulence model was used to simulate the model with unstructured mesh. Sliding mesh interface was used at the interface between the rotating and stationary domains to capture the unsteady interactions. An accurate assessment of the present investigation is made by comparing various parameters with the available experimental data. Three impeller geometries with different blade angles and radius ratio are used in the present study. Maximum energy transfer through the impeller takes place in the region where the flow follows the blade curvature. Radial velocity is not uniform through blade channels. Some blades work in turbine mode at very low flow coefficients. Static pressure is always negative in and around the impeller region.

  3. Comparison of leading parallel NAS file systems on commodity hardware

    SciTech Connect

    Hedges, R; Fitzgerald, K; Gary, M; Stearman, D M

    2010-11-08

    High performance computing has experienced tremendous gains in system performance over the past 20 years. Unfortunately other system capabilities, such as file I/O, have not grown commensurately. In this activity, we present the results of our tests of two leading file systems (GPFS and Lustre) on the same physical hardware. This hardware is the standard commodity storage solution in use at LLNL and, while much smaller in size, is intended to enable us to learn about differences between the two systems in terms of performance, ease of use and resilience. This work represents the first hardware consistent study of the two leading file systems that the authors are aware of.

  4. Case for Deploying Complex Systems Utilizing Commodity Components

    NASA Technical Reports Server (NTRS)

    Bryant, Barry S.; Pitts, R. Lee; Ritter, George

    2003-01-01

    This viewgraph representation presents a study of the transition of computer networks and software engineering at the Huntsville Operations Support Center (HOSC) from a client/server UNIX based system to a client/server system based on commodity priced and open system components. Topics covered include: an overview of HOSC ground support systems, an analysis for changes to the existing ground support system, an analysis of options considered for the transition to a new system, and a consideration of goals for a new system.

  5. Two-Phase Flow within Geological Flow Analogies--A Computational Study

    SciTech Connect

    Crandall, D.M.; Ahmadi, G.; Smith, D.H.; Ferer, M.V.; Richards, M.; Bromhal, G.S.

    2006-10-01

    Displacement of a viscous fluid in heterogeneous geological media by a less viscous one does not evacuate 100% of the defending fluid due to capillary and viscous fingering. This is of importance in geological flows that are encountered in secondary oil recovery and carbon dioxide sequestration in saturated brine fields. Hele-Shaw and pore/throat cells are commonly used to study this in the labratory. Numerical simulations of this flow phenomenon with pore-throat models have been prevalent for over two decades. This current work solves the full Navier-Stokes equations of conservation within random pore-throat geometries with varying properties to study the resulting flow properties. Verification of the solution method is performed by comparison of the model predictions with the available experimental data in the literature. Experimental flows in a pore-throat cell with a known geometrical structure are shown to be in good agreement with the model. Dynamic comparisons to a computational pore-throat model have been shown to be in good agreement as well. There are also additional two-phase immiscible flow patterns that can be identified from the current solutions for which the corresponding laboratory counter part or the pore-throat model predictions are not available. The identification of these flow patterns may allow more accurate modeling of fluid displacement on the reservoir scale.

  6. Study on flow instability and countermeasure in a draft tube with swirling flow

    NASA Astrophysics Data System (ADS)

    Nakashima, T.; Matsuzaka, R.; Miyagawa, K.; Yonezawa, K.; Tsujimoto, Y.

    2014-03-01

    The swirling flow in the draft tube of a Francis turbine can cause the flow instability and the cavitation surge and has a larger influence on hydraulic power operating system. In this paper, the cavitating flow with swirling flow in the diffuser was studied by the draft tube component experiment, the model Francis turbine experiment and the numerical simulation. In the component experiment, several types of fluctuations were observed, including the cavitation surge and the vortex rope behaviour by the swirling flow. While the cavitation surge and the vortex rope behaviour were suppressed by the aeration into the diffuser, the loss coefficient in the diffuser increased by the aeration. In the model turbine test the aeration decreased the efficiency of the model turbine by several percent. In the numerical simulation, the cavitating flow was studied using Scale-Adaptive Simulation (SAS) with particular emphasis on understanding the unsteady characteristics of the vortex rope structure. The generation and evolution of the vortex rope structures have been investigated throughout the diffuser using the iso-surface of vapor volume fraction. The pressure fluctuation in the diffuser by numerical simulation confirmed the cavitation surge observed in the experiment. Finally, this pressure fluctuation of the cavitation surge was examined and interpreted by CFD.

  7. Analytical studies of hypersonic viscous dissociated flows

    NASA Technical Reports Server (NTRS)

    Inger, George R.

    1995-01-01

    This project primarily dealt with integral boundary-layer solution techniques that are directly applicable to the problem of determining aerodynamic heating rates of hypersonic vehicles like X-33 in the vicinity of stagnation points, windward centerlines, and swept-wing leading edges. The analyses include effects of finite-rate gas chemistry across the boundary layer and finite-rate catalysis of atom recombination at the surface. A new approach for combining the insight afforded by integral boundary-layer analysis with comprehensive (and expensive) computational fluid dynamic (CFD) flowfield solutions of the thin-layer Navier-Stokes equations was developed. The approach extracts CFD derived quantities at the wall and at the boundary layer edge for inclusion in a post-processing boundary-layer analysis. The post-processed data base allows a designer at a workstation to ask and answer the following questions: (1) How much does the heating change if one uses a thermal protection system (TPS) with different catalytic properties than was used in the original CFD solution? (2) How does the heating change when one moves the interface of two different TPS materials with different catalytic efficiencies for the purpose of reducing vehicle weight and expense? The answer to the second question is particularly critical, because abrupt changes from low catalytic efficiency to high catalytic efficiency can lead to localized increase in heating which exceeds the usually conservative estimate provided by a fully catalytic wall assumption. A secondary issue that was addressed involves the prediction of heating levels in the vicinity of sharp corners that are transverse to or aligned with the flow. An example of the first case is heating at the edge of the COMET reentry module. An example of the second case is heating along the side edge of a deflected body flap on an SSV. The difficulty of putting grids in the vicinity of such corners with continuously varying metric coefficients

  8. Ground Based Studies of Thermocapillary Flows in Levitated Drops

    NASA Technical Reports Server (NTRS)

    Sadhal, Satwindar Singh; Trinh, Eugene H.

    1996-01-01

    Ground-based experiments together with analytical studies are presently being conducted for levitated drops. Both acoustic and electrostatic techniques are being employed to achieve levitation of drops in a gaseous environment. The scientific effort is principally on the thermal and the fluid phenomena associated with the local heating of levitated drops, both at 1-g and at low-g. In particular, the thermocapillary flow associated with local spot heating is being studied. Fairly stable acoustic levitation of drops has been achieved with some exceptions when random rotational motion of the drop persists. The flow visualization has been carried out by light scattering from smoke particles for the exterior flow and fluorescent tracer particles in the drop. The results indicate a lack of axial symmetry in the internal flow even though the apparatus and the heating are symmetric. The theoretical studies for the past year have included fundamental analyses of acoustically levitated spherical drops. The flow associated with a particle near the velocity antinode is being investigated by the singular perturbation technique. As a first step towards understanding the effect of the particle displacement from the antinode, the flow field about the node has been calculated for the first time. The effect of the acoustic field on the interior of a liquid drop has also been investigated. The results predict that the internal flow field is very weak.

  9. Theoretical study on the constricted flow phenomena in arteries

    NASA Astrophysics Data System (ADS)

    Sen, S.; Chakravarty, S.

    2012-12-01

    The present study is dealt with the constricted flow characteristics of blood in arteries by making use of an appropriate mathematical model. The constricted artery experiences the generated wall shear stress due to flow disturbances in the presence of constriction. The disturbed flow in the stenosed arterial segment causes malfunction of the cardiovascular system leading to serious health problems in the form of heart attack and stroke. The flowing blood contained in the stenosed artery is considered to be non-Newtonian while the flow is treated to be two-dimensional. The present pursuit also accounts for the motion of the arterial wall and its effect on local fluid mechanics. The flow analysis applies the time-dependent, two-dimensional incompressible nonlinear Navier-Stokes equations for non-Newtonian fluid representing blood. An extensive quantitative analysis presented at the end of the paper based on large scale numerical computations of the quantities of major physiological significance enables one to estimate the constricted flow characteristics in the arterial system under consideration which deviates significantly from that of normal physiological flow conditions.

  10. Will Commodity Properties Affect Seller's Creditworthy: Evidence in C2C E-commerce Market in China

    NASA Astrophysics Data System (ADS)

    Peng, Hui; Ling, Min

    This paper finds out that the credit rating level shows significant difference among different sub-commodity markets in E-commerce, which provides room for sellers to get higher credit rating by entering businesses with higher average credit level before fraud. In order to study the influence of commodity properties on credit rating, this paper analyzes how commodity properties affect average crediting rating through the degree of information asymmetry, returns and costs of fraud, credibility perception and fraud tolerance. Empirical study shows that Delivery, average trading volume, average price and complaint possibility have decisive impacts on credit performance; brand market share, the degree of standardization and the degree of imitation also have a relatively less significant effect on credit rating. Finally, this paper suggests that important commodity properties should be introduced to modify reputation system, for preventing credit rating arbitrage behavior where sellers move into low-rating commodity after being assigned high credit rating.

  11. Nuclear mgnetic resonance study of granular flows. Final report

    SciTech Connect

    1995-03-01

    We have demonstrated the efficacy of NMRI to granular flow studies of objects that yield NMR signals (seeds, pharmaceutical pills) in confined spaces (rotating cylinders, shaking boxes). Excellent results for velocity and concentration of flowing and colliding particles have been obtained non-invasively. We studied flows in geometries that are otherwise impossible to study because of the optical opacity of the materials. In addition, we obtained data for diffusion and collisional losses which must be related to granular temperature. We also measured the global collisional and frictional energy loss for a rotating cylinder containing granular material and compared it to that obtained from the NMRI velocity and acceleration data. We used the same NMR technique to study the interplay between radial and axial segregation of heterogeneous particles in a partially filled rotating cylinder. We also measured flow and diffusion of vibrating particles in the NMRI apparatus to ascertain that such experiments are, indeed, possible. Some theoretical studies were initiated to explain some of the velocity profiles and free surface shapes of rotating drum flow. A direct numerical simulation of the drum flow successfully predicted a number of features, including velocity, concentration, and dissipation profiles in rotating cylinders.

  12. Computer-generated mineral commodity deposit maps

    USGS Publications Warehouse

    Schruben, Paul G.; Hanley, J. Thomas

    1983-01-01

    This report describes an automated method of generating deposit maps of mineral commodity information. In addition, it serves as a user's manual for the authors' mapping system. Procedures were developed which allow commodity specialists to enter deposit information, retrieve selected data, and plot deposit symbols in any geographic area within the conterminous United States. The mapping system uses both micro- and mainframe computers. The microcomputer is used to input and retrieve information, thus minimizing computing charges. The mainframe computer is used to generate map plots which are printed by a Calcomp plotter. Selector V data base system is employed for input and retrieval on the microcomputer. A general mapping program (Genmap) was written in FORTRAN for use on the mainframe computer. Genmap can plot fifteen symbol types (for point locations) in three sizes. The user can assign symbol types to data items interactively. Individual map symbols can be labeled with a number or the deposit name. Genmap also provides several geographic boundary file and window options.

  13. Flow Liner Slot Edge Replication Feasibility Study

    NASA Technical Reports Server (NTRS)

    Newman, John A.; Willard, Scott A.; Smith, Stephen W.; Piascik, Robert S.

    2006-01-01

    Surface replication has been proposed as a method for crack detection in space shuttle main engine flowliner slots. The results of a feasibility study show that examination of surface replicas with a scanning electron microscope can result in the detection of cracks as small as 0.005 inch, and surface flaws as small as 0.001 inch, for the flowliner material.

  14. A novel planar flow cell for studies of biofilm heterogeneity and flow-biofilm interactions

    PubMed Central

    Zhang, Wei; Sileika, Tadas S.; Chen, Cheng; Liu, Yang; Lee, Jisun; Packman, Aaron I.

    2012-01-01

    Biofilms are microbial communities growing on surfaces, and are ubiquitous in nature, in bioreactors, and in human infection. Coupling between physical, chemical, and biological processes is known to regulate the development of biofilms; however, current experimental systems do not provide sufficient control of environmental conditions to enable detailed investigations of these complex interactions. We developed a novel planar flow cell that supports biofilm growth under complex two-dimensional fluid flow conditions. This device provides precise control of flow conditions and can be used to create well-defined physical and chemical gradients that significantly affect biofilm heterogeneity. Moreover, the top and bottom of the flow chamber are transparent, so biofilm growth and flow conditions are fully observable using non-invasive confocal microscopy and high-resolution video imaging. To demonstrate the capability of the device, we observed the growth of Pseudomonas aeruginosa biofilms under imposed flow gradients. We found a positive relationship between patterns of fluid velocity and biofilm biomass because of faster microbial growth under conditions of greater local nutrient influx, but this relationship eventually reversed because high hydrodynamic shear leads to the detachment of cells from the surface. These results reveal that flow gradients play a critical role in the development of biofilm communities. By providing new capability for observing biofilm growth, solute and particle transport, and net chemical transformations under user-specified environmental gradients, this new planar flow cell system has broad utility for studies of environmental biotechnology and basic biofilm microbiology, as well as applications in bioreactor design, environmental engineering, biogeochemistry, geomicrobiology, and biomedical research. PMID:21656713

  15. Simulation and study of stratified flows around finite bodies

    NASA Astrophysics Data System (ADS)

    Gushchin, V. A.; Matyushin, P. V.

    2016-06-01

    The flows past a sphere and a square cylinder of diameter d moving horizontally at the velocity U in a linearly density-stratified viscous incompressible fluid are studied. The flows are described by the Navier-Stokes equations in the Boussinesq approximation. Variations in the spatial vortex structure of the flows are analyzed in detail in a wide range of dimensionless parameters (such as the Reynolds number Re = Ud/ ν and the internal Froude number Fr = U/( Nd), where ν is the kinematic viscosity and N is the buoyancy frequency) by applying mathematical simulation (on supercomputers of Joint Supercomputer Center of the Russian Academy of Sciences) and three-dimensional flow visualization. At 0.005 < Fr < 100, the classification of flow regimes for the sphere (for 1 < Re < 500) and for the cylinder (for 1 < Re < 200) is improved. At Fr = 0 (i.e., at U = 0), the problem of diffusion-induced flow past a sphere leading to the formation of horizontal density layers near the sphere's upper and lower poles is considered. At Fr = 0.1 and Re = 50, the formation of a steady flow past a square cylinder with wavy hanging density layers in the wake is studied in detail.

  16. Study of two-phase flows in reduced gravity

    NASA Astrophysics Data System (ADS)

    Roy, Tirthankar

    Study of gas-liquid two-phase flows under reduced gravity conditions is extremely important. One of the major applications of gas-liquid two-phase flows under reduced gravity conditions is in the design of active thermal control systems for future space applications. Previous space crafts were characterized by low heat generation within the spacecraft which needed to be redistributed within the craft or rejected to space. This task could easily have been accomplished by pumped single-phase loops or passive systems such as heat pipes and so on. However with increase in heat generation within the space craft as predicted for future missions, pumped boiling two-phase flows are being considered. This is because of higher heat transfer co-efficients associated with boiling heat transfer among other advantages. Two-phase flows under reduced gravity conditions also find important applications in space propulsion as in space nuclear power reactors as well as in many other life support systems of space crafts. Two-fluid model along with Interfacial Area Transport Equation (IATE) is a useful tool available to predict the behavior of gas-liquid two-phase flows under reduced gravity conditions. It should be noted that considerable differences exist between two-phase flows under reduced and normal gravity conditions especially for low inertia flows. This is because due to suppression of the gravity field the gas-liquid two-phase flows take a considerable time to develop under reduced gravity conditions as compared to normal gravity conditions. Hence other common methods of analysis applicable for fully developed gas-liquid two-phase flows under normal gravity conditions, like flow regimes and flow regime transition criteria, will not be applicable to gas-liquid two-phase flows under reduced gravity conditions. However the two-fluid model and the IATE need to be evaluated first against detailed experimental data obtained under reduced gravity conditions. Although lot of studies

  17. Storage Methods for Food Commodities. Food Commodities Lesson Plan No. 1.

    ERIC Educational Resources Information Center

    Li, Anita

    Designed as part of a 15-hour community college course in food commodities, this lesson plan was developed to teach students about the proper storage of food. The lesson plan begins with information about the course for which the lesson plan was designed; equipment and audiovisual aids needed; requirements for student materials; course objectives;…

  18. 76 FR 11701 - Amendments to Commodity Pool Operator and Commodity Trading Advisor Regulations Resulting From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-03

    ... would establish business conduct standards for swap dealers and major swap participants. See 75 FR 80638... and Commodity Trading Advisors: Amendments to Compliance Obligations, 76 FR 7976 (Feb. 11, 2011); and Swap Data Recordkeeping and Reporting Requirements; Proposed Rule, 75 FR 76574 (Dec. 8, 2010). II....

  19. Retail Commodity Intakes: Mean Amounts of Retail Commodities per Individual, 2003-04

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The table set includes national estimates in terms of mean gram amounts of retail commodities consumed per person estimated from the day 1 dietary intake data of 8,272 individuals, ages 2 years and over, in What We Eat In America, National Health and Nutrition Examination Survey, 2003-2004 and Food ...

  20. Retail Commodity Intakes: Mean Amounts of Retail Commodities per Individual, 2005-06

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The table set includes national estimates in terms of mean gram amounts of retail commodities consumed per person estimated from the day 1 dietary intake data of 8,549 individuals, ages 2 years and over, in What We Eat In America, National Health and Nutrition Examination Survey, 2005-2006 and Food ...

  1. Retail food commodity intakes: Mean amounts of retail commodities per individual, 2001-2002

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The table sets of national estimates of the amounts of retail commodities per person were estimated from the day 1 dietary intake data of 9,033 individuals, ages 2 years and over, in What We Eat In America, National Health and Nutrition Examination Survey 2001-2002 using the Food Intakes Converted t...

  2. Retail Commodity Intakes: Mean Amounts of Retail Commodities per Individual, 2007-08

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The table set includes national estimates in terms of mean gram amounts of retail commodities consumed per person estimated from the day 1 dietary intake data of 8,528 individuals, ages 2 years and over, in What We Eat In America, National Health and Nutrition Examination Survey, 2007-2008 and Food ...

  3. A study of vapor-liquid flow in porous media

    SciTech Connect

    Satik, Cengiz; Yortsos, Yanis C.

    1994-01-20

    We study the heat transfer-driven liquid-to-vapor phase change in single-component systems in porous media by using pore network models and flow visualization experiments. Experiments using glass micromodels were conducted. The flow visualization allowed us to define the rules for the numerical pore network model. A numerical pore network model is developed for vapor-liquid displacement where fluid flow, heat transfer and capillarity are included at the pore level. We examine the growth process at two different boundary conditions.

  4. Studies in Forced and Time Varying Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Grosch, Chester E.

    2005-01-01

    The reasearch focused on two areas; (a) the dynamics of forced turbulent flows and (b) time filtered Large Eddy Simulations (TLES). The dynamics of turbulent flows arising from external forcing of the turbulence are poorly understood. In particular, here are many unanswered questions relating the basic dynamical balances and the existence or nonexistence of statistical equilibrium of forced turbulent flows. This research used rapid distortion theory and direct numerical simulations to explore these questions. The properties of the temporally filtered Navier-Stokes equations were also studied.

  5. Concentrated Flow through a Riparian Buffer: A Case Study

    NASA Astrophysics Data System (ADS)

    Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

    2005-05-01

    Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extent to which flow concentration affects buffer efficiency. Recommendations are presented for the design of adaptive-width buffers.

  6. Concentrated Flow through a Riparian Buffer: A Case Study

    NASA Astrophysics Data System (ADS)

    Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

    2004-05-01

    Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extend to which flow concentration affects buffer efficiency.

  7. Orbital transfer vehicle launch operations study. Processing flows. Volume 3

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The Orbit Transfer Vehicle (OTV) processing flow and Resource Identification Sheets (RISs) for the ground based orbit transfer vehicle and for the space based orbit transfer vehicle are the primary source of information for the rest of the Kennedy Space Center (KSC) OTV Launch Operations Study. Work is presented which identifies KSC facility requirements for the OTV Program, simplifies or automates either flow though the application technology, revises test practices and identifies crew sizes or skills used. These flows were used as the primary point of departure from current operations and practices. Analyses results were documented by revising the appropriate RIS page.

  8. Experimental studies of unsteady flow through compliant vessels

    NASA Astrophysics Data System (ADS)

    Sturgeon, Victoria; Saloner, David; Savas, Omer

    2003-11-01

    Hemodynamic forces are a significant cause of device failure when stent-grafts are used to treat abdominal aortic aneurysms and even have a strong causative relationship with the very formation and rupture of atherosclerosis. A better comprehension of the forces at play in this environment is highly desirable in furthering the understanding and treatment of aneurysmal diseases. The purpose of this experimental study is to characterize the behavior of physiologically correct pulsatile input flow in a straight compliant vessel as an analog for the behavior in an abdominal aorta. Flow visualization and particle image velocimetry are used to study the flow in simplified geometries replicating healthy and diseased segments of human abdominal aorta. The effects of external pressure are examined to shed light on the interactions between pressure differential across the vessel wall, blood flow, and vessel deformation.

  9. Low-level atmospheric flows studied by pulsed Doppler lidar

    NASA Technical Reports Server (NTRS)

    Banta, Robert M.; Olivier, Lisa D.; Hardesty, R. Michael

    1992-01-01

    A pulsed Doppler radar gains a tremendous advantage in studying atmospheric flows when it has the ability to scan. The Wave Propagation Laboratory (WPL) has been operating a scanning, 10.59 micron CO2 system for over 10 years. Recently, the WPL lidar has been a featured instrument in several investigations of mesoscale wind fields in the lowest 3-4 km of the atmosphere. These include four experiments: a study of the initiation and growth of the sea breeze off the coast of California, a study of the snake column of a prescribed forest fire, a study of the nighttime flow over the complex terrain near Rocky Flats, Colorado as it affects the dispersion of atmospheric contaminants, and a study of the wind flow in the Grand Canyon. We have analyzed much data from these experiments, and we have found that the lidar provides new insight into the structure of these flows. Many of these studies took place in rugged or mountainous terrain, thus using one of the major benefits of the lidar: the narrow, 90 microrad beam of the lidar makes it an ideal instrument for studying flow close to topography.

  10. Study of the Transition Flow Regime using Monte Carlo Methods

    NASA Technical Reports Server (NTRS)

    Hassan, H. A.

    1999-01-01

    This NASA Cooperative Agreement presents a study of the Transition Flow Regime Using Monte Carlo Methods. The topics included in this final report are: 1) New Direct Simulation Monte Carlo (DSMC) procedures; 2) The DS3W and DS2A Programs; 3) Papers presented; 4) Miscellaneous Applications and Program Modifications; 5) Solution of Transitional Wake Flows at Mach 10; and 6) Turbulence Modeling of Shock-Dominated Fows with a k-Enstrophy Formulation.

  11. Education: Commodity, Come-On, or Commitment?

    NASA Astrophysics Data System (ADS)

    Moore, John W.

    2000-07-01

    July 4, and the glass art shown on pages 812-816, remind us that freedom is fragile. Through their governments, citizens of democracies have traditionally made strong commitments to education on grounds that without it individuals would not be able to act responsibly and to make wise decisions in voting booths and public meetings. All citizens have a stake in everyone's education, because a better-educated citizenry benefits all of society. In this country such a commitment has produced a system of public schools and public universities that offers opportunities to many who otherwise could not afford a level of education commensurate with their talents. But there are signs that this commitment to public education is flagging. Many students, teachers, and administrators view education as merely a way to enhance personal prosperity. How often have you heard the statistic that a college education pays for itself through increased earning power, even if it costs $20,000-30,000 per year? Investing in education pays off just as investing in the stock market does, provided you wait long enough. Attending a better school gets you a better job and a better income. In other words, a certified level of education is a commodity-something that is useful and can be turned to commercial advantage. Viewing education as a commodity has several consequences. First, if education is a means to better employment rather than better citizenship, why should anyone pay for it other than the person who benefits? Why should I pay taxes to help someone else get a better job when I could be spending the money for my own benefit? Education as a commodity makes such attitudes reasonable, though not commendable, and the result is lessened support for public education. Second, those who supply education as an economic good should be rewarded, and those who are much better at educating should be rewarded much more. Hence the fear of Arthur Levine, president of Teachers College, Columbia University

  12. Ground based studies of thermocapillary flows in levitated drops

    NASA Technical Reports Server (NTRS)

    Sadhal, Satwindar Singh; Trinh, Eugene H.

    1994-01-01

    Analytical studies along with ground-based experiments are presently being carried out in connection with thermocapillary phenomena associated with drops and bubbles in a containerless environment. The effort here focuses on the thermal and the fluid phenomena associated with the local heating of acoustically levitated drops, both at 1-g and at low-g. In particular, the Marangoni effect on drops under conditions of local spot-heating and other types of heating are being studied. With the experiments conducted to date, fairly stable acoustic levitation of drops has been achieved and successful flow visualization by light scattering from smoke particles has been carried out. The results include situations with and without heating. As a preliminary qualitative interpretation of these experimental results, we consider the external flow pattern as a superposition of three discrete circulation cells operating on different spatial scales. The observations of the flow fields also indicate the existence of a steady state torque induced by the streaming flows. The theoretical studies have been concentrated on the analysis of streaming flows in a gaseous medium with the presence of a spherical particle undergoing periodic heating. A matched asymptotic analysis was carried out for small parameters derived from approximations in the high frequency range. The heating frequency being 'in tune' with the acoustic frequency results in a nonzero time-averaged thermal field. This leads to a steady heat flow across the equatorial plane of the sphere.

  13. A preliminary study to Assess Model Uncertainties in Fluid Flows

    SciTech Connect

    Marc Oliver Delchini; Jean C. Ragusa

    2009-09-01

    The goal of this study is to assess the impact of various flow models for a simplified primary coolant loop of a light water nuclear reactor. The various fluid flow models are based on the Euler equations with an additional friction term, gravity term, momentum source, and energy source. The geometric model is purposefully chosen simple and consists of a one-dimensional (1D) loop system in order to focus the study on the validity of various fluid flow approximations. The 1D loop system is represented by a rectangle; the fluid is heated up along one of the vertical legs and cooled down along the opposite leg. A pressurizer and a pump are included in the horizontal legs. The amount of energy transferred and removed from the system is equal in absolute value along the two vertical legs. The various fluid flow approximations are compressible vs. incompressible, and complete momentum equation vs. Darcy’s approximation. The ultimate goal is to compute the fluid flow models’ uncertainties and, if possible, to generate validity ranges for these models when applied to reactor analysis. We also limit this study to single phase flows with low-Mach numbers. As a result, sound waves carry a very small amount of energy in this particular case. A standard finite volume method is used for the spatial discretization of the system.

  14. A water tunnel flow visualization study of the F-15

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1978-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the F-15 aircraft. Two lengthened forebodies, one with a modified cross-sectional shape, were tested in addition to the basic forebody. Particular emphasis was placed on defining vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop diagnostic water tunnel using a 1/48-scale model of the F-15. Flow visualization pictures were obtained over an angle-of-attack range to 55 deg and sideslip angles up to 10 deg. The basic aircraft configuration was investigated in detail to determine the vortex flow field development, vortex path, and vortex breakdown characteristics as a function of angle of attack and sideslip. Additional tests showed that the wing upper surface vortex flow fields were sensitive to variations in inlet mass flow ratio and inlet cowl deflection angle. Asymmetries in the vortex systems generated by each of the three forebodies were observed in the water tunnel at zero sideslip and high angles of attack.

  15. 17 CFR 4.14 - Exemption from registration as a commodity trading advisor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... a commodity trading advisor. 4.14 Section 4.14 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION COMMODITY POOL OPERATORS AND COMMODITY TRADING ADVISORS General Provisions, Definitions and Exemptions § 4.14 Exemption from registration as a commodity trading advisor. This section...

  16. 17 CFR 33.10 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Fraud in connection with commodity option transactions. 33.10 Section 33.10 Commodity and Securities Exchanges COMMODITY FUTURES... COMMODITY FOR FUTURE DELIVERY § 33.10 Fraud in connection with commodity option transactions. It shall...

  17. 17 CFR 33.10 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Fraud in connection with commodity option transactions. 33.10 Section 33.10 Commodity and Securities Exchanges COMMODITY FUTURES... COMMODITY FOR FUTURE DELIVERY § 33.10 Fraud in connection with commodity option transactions. It shall...

  18. 17 CFR 32.12 - Exemption from suspension of commodity option transactions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 1 2011-04-01 2011-04-01 false Exemption from suspension of commodity option transactions. 32.12 Section 32.12 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.12 Exemption from suspension of commodity option transactions. (a)...

  19. 17 CFR 4.14 - Exemption from registration as a commodity trading advisor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... a commodity trading advisor. 4.14 Section 4.14 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION COMMODITY POOL OPERATORS AND COMMODITY TRADING ADVISORS General Provisions, Definitions and Exemptions § 4.14 Exemption from registration as a commodity trading advisor. This section...

  20. 17 CFR 4.14 - Exemption from registration as a commodity trading advisor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... a commodity trading advisor. 4.14 Section 4.14 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION COMMODITY POOL OPERATORS AND COMMODITY TRADING ADVISORS General Provisions, Definitions and Exemptions § 4.14 Exemption from registration as a commodity trading advisor. This section...

  1. 17 CFR 4.14 - Exemption from registration as a commodity trading advisor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... a commodity trading advisor. 4.14 Section 4.14 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION COMMODITY POOL OPERATORS AND COMMODITY TRADING ADVISORS General Provisions, Definitions and Exemptions § 4.14 Exemption from registration as a commodity trading advisor. This section...

  2. 17 CFR Appendix D to Part 43 - Other Commodity Swap Categories

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 2 2014-04-01 2014-04-01 false Other Commodity Swap Categories D Appendix D to Part 43 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION (CONTINUED) REAL-TIME PUBLIC REPORTING Pt. 43, App. D Appendix D to Part 43—Other Commodity Swap Categories Other Commodity Group Individual...

  3. Study of the velocity gradient tensor in turbulent flow

    NASA Technical Reports Server (NTRS)

    Cheng, Wei-Ping; Cantwell, Brian

    1996-01-01

    The behavior of the velocity gradient tensor, A(ij)=delta u(i)/delta x(j), was studied using three turbulent flows obtained from direct numerical simulation The flows studies were: an inviscid calculation of the interaction between two vortex tubes, a homogeneous isotropic flow, and a temporally evolving planar wake. Self-similar behavior for each flow was obtained when A(ij) was normalized with the mean strain rate. The case of the interaction between two vortex tubes revealed a finite sized coherent structure with topological characteristics predictable by a restricted Euler model. This structure was found to evolve with the peak vorticity as the flow approached singularity. Invariants of A(ij) within this structure followed a straight line relationship of the form: gamma(sup 3)+gammaQ+R=0, where Q and R are the second and third invariants of A(ij), and the eigenvalue gamma is nearly constant over the volume of this structure. Data within this structure have local strain topology of unstable-node/saddle/saddle. The characteristics of the velocity gradient tensor and the anisotropic part of a related acceleration gradient tensor H(ij) were also studied for a homogeneous isotropic flow and a temporally evolving planar wake. It was found that the intermediate principal eigenvalue of the rate-of-strain tensor of H(ij) tended to be negative, with local strain topology of the type stable-node/saddle/saddle. There was also a preferential eigenvalue direction. The magnitude of H(ij) in the wake flow was found to be very small when data were conditioned at high local dissipation regions. This result was not observed in the relatively low Reynolds number simulation of homogeneous isotropic flow. A restricted Euler model of the evolution of A(ij) was found to reproduce many of the topological features identified in the simulations.

  4. Numerical study of free surface flow around large obstacles

    NASA Astrophysics Data System (ADS)

    Zhang, Yanming

    In this thesis a numerical model was developed to study three-dimensional turbulent flows around large obstacles in an open channel. With this numerical model, a series of numerical tests was carried out, and the properties of turbulent flows around a single obstacle or a cluster of obstacles were investigated. The origin of this study was to study the flow properties around fish habitat structures. Actually, the numerical model can be applied to the study of general turbulent flows under free surfaces. In the numerical model the three-dimensional Reynolds-averaged Navier-Stokes equations in conjunction with k-epsilon turbulence model were solved in a free surface fitted coordinate system. First, different forms of governing equations for turbulent flow were investigated, and a concise form of fully transformed governing equations in a general curvilinear coordinate system was derived. In the numerical solution the FAVOR (Fractional Area/Volume Obstacle Representation) technique was extended into the free surface fitted coordinate system. With this feature the problem of complex turbulent flow with a free surface and general shaped obstacles could be solved efficiently. To locate the free surface, a method based on integrating the momentum equation in the vertical direction was developed. After study and tests of several popular difference schemes, a QUICK scheme with UMIST limiter was adopted in this numerical model. Several test cases were presented to demonstrate the present numerical model. The first test case was to simulate a submerged hydraulic jump. The calculated velocity, free surface profile and turbulence properties of the flow showed a close match with the experimental data. The second test was a submerged hydraulic jump with a baffle sill. The comparison between numerical and experimental data indicated that the current numerical model could catch the general flow structures of the submerged hydraulic jumps. The last two test cases were flows around a

  5. Systematic study of source mask optimization and verification flows

    NASA Astrophysics Data System (ADS)

    Ben, Yu; Latypov, Azat; Chua, Gek Soon; Zou, Yi

    2012-06-01

    Source mask optimization (SMO) emerged as powerful resolution enhancement technique (RET) for advanced technology nodes. However, there is a plethora of flow and verification metrics in the field, confounding the end user of the technique. Systemic study of different flows and the possible unification thereof is missing. This contribution is intended to reveal the pros and cons of different SMO approaches and verification metrics, understand the commonality and difference, and provide a generic guideline for RET selection via SMO. The paper discusses 3 different type of variations commonly arise in SMO, namely pattern preparation & selection, availability of relevant OPC recipe for freeform source and finally the metrics used in source verification. Several pattern selection algorithms are compared and advantages of systematic pattern selection algorithms are discussed. In the absence of a full resist model for SMO, alternative SMO flow without full resist model is reviewed. Preferred verification flow with quality metrics of DOF and MEEF is examined.

  6. Experimental and numerical study on condensation in transonic steam flow

    NASA Astrophysics Data System (ADS)

    Majkut, Mirosław; Dykas, Sławomir; Strozik, Michał; Smołka, Krystian

    2015-09-01

    The present paper describes an experimental and numerical study of steam condensing flow in a linear cascade of turbine stator blades. The experimental research was performed on the facility of a small scale steam power plant located at Silesian University of Technology in Gliwice, Poland. The test rig of the facility allows us to perform the tests of steam transonic flows for the conditions corresponding to these which prevail in the low-pressure (LP) condensing steam turbine stages. The experimental data of steam condensing flow through the blade-to- blade stator channel were compared with numerical results obtained using the in-house CFD numerical code TraCoFlow. Obtained results confirmed a good quality of the performed experiment and numerical calculations.

  7. Experimental study of periodic flow effects on spanwise vortex

    NASA Astrophysics Data System (ADS)

    Garcia Molina, Cruz Daniel; Lopez Sanchez, Erick Javier; Ruiz Chavarria, Gerardo; Medina Ovando, Abraham

    2014-11-01

    We present an experimental study about the spanwise vortex produced in a flow going out of a channel in shallow waters. This vortex travels in front of the dipole. The velocity field measurement was done using the PIV technique, and DPIVsoft (https://www.irphe.fr/ ~meunier/) was used for data processing. In this case the flow has a periodic forcing to simulate ocean tides. The experiment was conducted in a channel with variable width and the measurements were made using three different values of the aspect ratio width-depth. We present results of the position, circulation of this spanwise vortex and the flow inversion effect. The change of flow direction modify the intensity of the vortex, but it does not destroy it. The vertical components of the velocity field contributes particle transport. G. Ruiz Chavarria, E. J. Lopez Sanchez and C. D. Garcia Molina acknowledge DGAPA-UNAM by support under project IN 116312 (Vorticidad y ondas no lineales en fluidos).

  8. Experimental Study on Swirl Flow in an ECR Plasma

    NASA Astrophysics Data System (ADS)

    Terasaka, Kenichiro; Yoshimura, Shinji; Furuta, Kanshi; Yamada, Takuya; Tanaka, Masayoshi

    2015-11-01

    Swirl plasma flow plays an important role to clarify astrophysical phenomena, such as astrophysical jets and solar dynamo, and in the development of plasma propulsion systems. We have studied the effect of plasma rotation on flow structure formation in a cylindrical ECR plasma with the HYPER-II device at Kyushu University, Japan. The HYPER-II device consists of two cylindrical chambers with different diameters: one is the plasma production chamber with 0.3 m in diameter and 0.95 m in axial length, and the other is the diffusion chamber with 0.76 m in diameter and 1.3 m in axial length. An electron cyclotron resonance (ECR) plasma is produced by a 2.45 GHz microwave in the magnetic beach configuration. The azimuthal plasma rotation due to E × B drift is generated by a set of cylindrical electrodes, and the swirl plasma flow with various kinetic helicity is produced in a diverging magnetic field. An axially revers flow structure has been found near the center axis, in which the radial density profile exhibits a density build-up in the flow reversal region. The axial flow structure of rotating plasma shows an interesting behavior compared with non-rotating plasmas. This study was supported by JSPS KAKENHI grant number 15K05365.

  9. Nutrition and food commodities in the 20th century.

    PubMed

    Martini, Sharon A; Phillips, Marshall

    2009-09-23

    Nutrition in the 20th century is examined with respect to changes in the American diet due to changes in the economy and evolution from an agrarian to an industrialized society. The American farm family diet from two regions of the United States during the 1930s is studied on the basis of overall availability of food commodities. A discussion of the diet staples and differences in farm family health is presented and related to nutritional deficiencies. Beginning in the 1920s through the early 1930s dietary deficiencies became a major focus of public health officials in the United States. Identification of the cause of these human nutritional deficiencies prompted significant research by government agencies such as the U.S. Department of Agriculture, Food and Drug Administration, and National Institutes of Health. Medical schools, universities, pharmaceutical corporations, and private institutions directed their resources into basic chemical research and clinical trials to assess the role of vitamins, minerals, proteins, lipids, carbohydrates, and nutrients for improving human health and nutrition. Chemists played an important role in the discovery of vitamins, minerals, and essential nutrients, validating the efficacy through tedious clinical trials. They developed synthetic vitamins affording food manufacturers and pharmaceutical companies the opportunity to capitalize upon fortifying foods for consumers. The American chemist was also responsible for the development of commodities to maximize crop yield through pesticides and fertilizers. PMID:19719130

  10. Education: Commodity, Come-On, or Commitment?

    NASA Astrophysics Data System (ADS)

    Moore, John W.

    2000-07-01

    July 4, and the glass art shown on pages 812-816, remind us that freedom is fragile. Through their governments, citizens of democracies have traditionally made strong commitments to education on grounds that without it individuals would not be able to act responsibly and to make wise decisions in voting booths and public meetings. All citizens have a stake in everyone's education, because a better-educated citizenry benefits all of society. In this country such a commitment has produced a system of public schools and public universities that offers opportunities to many who otherwise could not afford a level of education commensurate with their talents. But there are signs that this commitment to public education is flagging. Many students, teachers, and administrators view education as merely a way to enhance personal prosperity. How often have you heard the statistic that a college education pays for itself through increased earning power, even if it costs $20,000-30,000 per year? Investing in education pays off just as investing in the stock market does, provided you wait long enough. Attending a better school gets you a better job and a better income. In other words, a certified level of education is a commodity-something that is useful and can be turned to commercial advantage. Viewing education as a commodity has several consequences. First, if education is a means to better employment rather than better citizenship, why should anyone pay for it other than the person who benefits? Why should I pay taxes to help someone else get a better job when I could be spending the money for my own benefit? Education as a commodity makes such attitudes reasonable, though not commendable, and the result is lessened support for public education. Second, those who supply education as an economic good should be rewarded, and those who are much better at educating should be rewarded much more. Hence the fear of Arthur Levine, president of Teachers College, Columbia University

  11. Theoretical and numerical studies of plume flows in vacuum chambers

    NASA Astrophysics Data System (ADS)

    Cai, Chunpei

    This thesis consists of three parts: a study of facility effects on the background flow in large vacuum chambers; an analytical study of free molecular flows out of exits with different shape representing thruster plumes; and particle simulations of plasma plume flows from a cluster of Hall thrusters. The first part of this thesis discusses the facility effects on large vacuum chambers, which is quite important to the Electric Propulsion (EP) community. Based on the fact that the background flows in large vacuum chambers equipped with cryogenic pumps are free molecular, five models are proposed to study the average background pressure and flow velocity and their relation to several facility effects, such as pump sticking coefficient, pump size, wall and pump temperatures, and chamber sidewall length. The analysis are based on the mass flow rates into and out of the chamber, the fluxes along two directions and various number density relations at various stations such as chamber ends and vacuum pumps. The second part of the thesis develops several sets of analytical solutions to free molecular flows out of exits with different shapes. It is demonstrated that the plasma plume flows expanding into vacuum can be studied analytically as a combination of several free molecular flows, if the electric field and collision effects are omitted. There exists a unique relation of velocity and positions. The last part of the thesis presents several three-dimensional particle simulations of plasma plume flows from a cluster of Hall thrusters. A detailed electron fluid model is used to solve important electron properties such as plasma potential and electron temperature. A finite element solver is developed to solve the equations of the electron properties on unstructured meshes. Several important implementation issues are discussed and one significant finding is that the class of particle-to-node weighting schemes based on areas or volumes on an unstructured mesh is inaccurate

  12. Computational Study of Separating Flow in a Planar Subsonic Diffuser

    NASA Technical Reports Server (NTRS)

    DalBello, Teryn; Dippold, Vance, III; Georgiadis, Nicholas J.

    2005-01-01

    A computational study of the separated flow through a 2-D asymmetric subsonic diffuser has been performed. The Wind Computational Fluid Dynamics code is used to predict the separation and reattachment behavior for an incompressible diffuser flow. The diffuser inlet flow is a two-dimensional, turbulent, and fully-developed channel flow with a Reynolds number of 20,000 based on the centerline velocity and the channel height. Wind solutions computed with the Menter SST, Chien k-epsilon, Spalart-Allmaras and Explicit Algebraic Reynolds Stress turbulence models are compared with experimentally measured velocity profiles and skin friction along the upper and lower walls. In addition to the turbulence model study, the effects of grid resolution and use of wall functions were investigated. The grid studies varied the number of grid points across the diffuser and varied the initial wall spacing from y(sup +) = 0.2 to 60. The wall function study assessed the applicability of wall functions for analysis of separated flow. The SST and Explicit Algebraic Stress models provide the best agreement with experimental data, and it is recommended wall functions should only be used with a high level of caution.

  13. Idea Cards for Water Flow. Elementary Science Study.

    ERIC Educational Resources Information Center

    Elementary Science Study, Newton, MA.

    Presented are 29 activity cards designed for use with the Elementary Science Study (ESS) program. Each card describes an experiment on one aspect of water flow such as siphoning, methods of removing water from a container, aspirators, floats, and water behavior in various tubing linkups. Activities are intended for individual or small group study;…

  14. 7 CFR 1493.5 - Criteria for agricultural commodity allocations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE EXPORT PROGRAMS CCC EXPORT CREDIT GUARANTEE PROGRAMS... allocations. The criteria considered by CCC in reviewing proposals for specific U.S. commodity...

  15. 7 CFR 1493.5 - Criteria for agricultural commodity allocations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE EXPORT PROGRAMS CCC EXPORT CREDIT GUARANTEE PROGRAMS... allocations. The criteria considered by CCC in reviewing proposals for specific U.S. commodity...

  16. 7 CFR 1493.5 - Criteria for agricultural commodity allocations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE EXPORT PROGRAMS CCC EXPORT CREDIT GUARANTEE PROGRAMS... allocations. The criteria considered by CCC in reviewing proposals for specific U.S. commodity...

  17. Analytical studies on the instabilities of heterogeneous intelligent traffic flow

    NASA Astrophysics Data System (ADS)

    Ngoduy, D.

    2013-10-01

    It has been widely reported in literature that a small perturbation in traffic flow such as a sudden deceleration of a vehicle could lead to the formation of traffic jams without a clear bottleneck. These traffic jams are usually related to instabilities in traffic flow. The applications of intelligent traffic systems are a potential solution to reduce the amplitude or to eliminate the formation of such traffic instabilities. A lot of research has been conducted to theoretically study the effect of intelligent vehicles, for example adaptive cruise control vehicles, using either computer simulation or analytical method. However, most current analytical research has only applied to single class traffic flow. To this end, the main topic of this paper is to perform a linear stability analysis to find the stability threshold of heterogeneous traffic flow using microscopic models, particularly the effect of intelligent vehicles on heterogeneous (or multi-class) traffic flow instabilities. The analytical results will show how intelligent vehicle percentages affect the stability of multi-class traffic flow.

  18. Flow Visualization Study of the F-14 Fighter Aircraft Configuration

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1980-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the F-14. Particular emphasis was placed on defining the vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop water tunnel using a 1/72 scale model of the F-14 with a wing leading-edge sweep of 20 deg. Flow visualization photographs were obtained for angles of attack up to 55 deg and sideslip angles up to 10 deg. The F-14 model was investigated to determine the vortex flow field development, vortex path, and vortex breakdown characteristics as a function of angle of attack and sideslip. Vortex flows were found to develop on the highly swept glove and on the upper surface of the forebody. At 10 deg of sideslip, the windward glove vortex shifted inboard and broke down farther forward than the leeward glove vortex. This asymmetric breakdown of the vortices in sideslip contributes to a reduction in the lateral stability above 20 deg angle of attack. The initial loss of directional stability is a consequence of the adverse sidewash from the windward vortex and the reduced dynamic pressure at the vertical tails.

  19. Performance and Flow Dynamics Studies of Polymeric Optofluidic SERS Sensors

    NASA Astrophysics Data System (ADS)

    Uusitalo, S.; Hiltunen, J.; Karioja, P.; Siitonen, S.; Kontturi, V.; Myllylä, R.; Kinnunen, M.; Meglinski, I.

    2015-09-01

    We present a polymer-based optofluidic surface enhanced Raman scattering chip for biomolecule detection, serving as a disposable sensor choice with cost-effective production. The SERS substrate is fabricated by using industrial roll-to-roll UV-nanoimprinting equipment and integrated with adhesive-based polymeric microfluidics. The functioning of the SERS detection on-chip is confirmed and the effect of the polymer lid on the obtainable Raman spectra is analysed. Rhodamine 6G is used as a model analyte to demonstrate continuous flow measurements on a planar SERS substrate in a microchannel. The relation between the temporal response of the sensors and sample flow dynamics is studied with varied flow velocities, using SERS and fluorescence detection. The response time of the surface-dependent SERS signal is longer than the response time of the fluorescence signal of the bulk flow. This observation revealed the effect of convection on the temporal SERS responses at 25 μl/min to 1000 µl/min flow velocities. The diffusion of analyte molecules from the bulk concentration into the sensing surface induces about a 40-second lag time in the SERS detection. This lag time, and its rising trend with slower flow velocities, has to be taken into account in future trials of the optofluidic SERS sensor, with active analyte binding on the sensing surface.

  20. Flow visualization study of the HiMAT RPRV

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1980-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the highly maneuverable aircraft technology remotely piloted research vehicle (HiMAT RPRV). Particular emphasis was placed on defining the vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop water tunnel using a 1/15 scale model of the HiMAT RPRV. Flow visualization photographs were obtained for angles of attack up to 40 deg and sideslip angles up to 5 deg. The HiMAT model was investigated in detail to determine the canard and wing vortex flow field development, vortex paths, and vortex breakdown characteristics as a function of angle of attack and sideslip. The presence of the canard caused the wing vortex to form further outboard and delayed the breakdown of the wing vortex to higher angles of attack. An increase in leading edge camber of the maneuver configuration delayed both the formation and the breakdown of the wing and canard vortices. Additional tests showed that the canard vortex was sensitive to variations in inlet mass flow ratio and canard flap deflection angle.

  1. Flow regime study of a light material in an industrial scale cold flow circulating fluidized bed

    SciTech Connect

    Mei, J.S.; Monazam, E.R.; Shadle, L.J.

    2006-06-15

    A series of experiments was conducted in the 0.3 meter diameter circulating fluidized bed test facility at the National Energy Technology Laboratory (NETL) of the U. S. Department of Energy. The particle used in this study was a coarse, light material, cork, which has a particle density of 189 kg/m{sup 3} and a mean diameter of 812 {mu}m. Fluidizing this material in ambient air approximates the same gas-solids density ratio as coal and coal char in a pressurized gasifier. The purpose of this study is twofold. First, this study is to provide a better understanding on the fundamentals of flow regimes and their transitions. The second purpose of this study is to generate reliable data to validate the mathematical models, which are currently under development at NETL. This paper presents and discusses the data, which covered operating flow regime from dilute phase, fast fluidization, and to dense phase transport by varying the solid flux, G{sub s}. at a constant gas velocity, U{sub g}. Data are presented by mapping the flow regime for coarse cork particles in a {Delta}P/{Delta} L-G{sub s}-U{sub g} plot. A stable operation can be obtained at a fixed riser gas velocity higher than the transport velocity e.g., at U{sub g} = 3.2 m/s, even though the riser is operated within the fast fluidization flow regime. Depending upon the solids influx, the riser can also be operated at dilute phase or dense phase flow regimes. Experimental data were compared to empirical correlations in published literature for flow regime boundaries as well as solids, fractions in the upper dilute and the lower dense regions for fast fluidization flow regime. Comparisons of measured data with these empirical correlations show rather poor agreements. These discrepancies, however, are not surprising since the correlations for these transitions were derived from experimental data of comparative heavier materials such as sands, FCC, iron ore etc.

  2. Quantifying Blood Flow in the DIEP Flap: An Ultrasonographic Study

    PubMed Central

    Pennington, David G.

    2014-01-01

    Background: The maximum weight of tissue that a single perforator can perfuse remains an important question in reconstructive microsurgery. An empirically based equation, known as the flap viability index (FVI), has been established to determine what weight of tissue will survive on one or more perforators. The equation is FVI = Sum d(n)^4/W, where d is the internal diameter of each perforator and W is the final weight of the flap. It has been shown that if FVI exceeds 10, total flap survival is likely, but if under 10, partial flap necrosis is probable. The aim of this study was to measure absolute flow rates in deep inferior epigastric perforator (DIEP) flap pedicles and assess correlation with the determinants of the FVI, perforator diameter and flap weight. Methods: Color Doppler ultrasound was used to quantify arterial flow in 10 consecutive DIEP flap pedicles 24 hours after anastomosis. Results: In single-perforator DIEP flaps, flow rate was highly correlated with perforator diameter (r = 0.82, P = 0.01). Mean arterial flow rate was significantly reduced in DIEP flaps with 2 or more perforators (6 vs 38 cm3/min; P < 0.05). Conclusions: This study confirms that perforator size is a critical factor in optimizing blood flow in perforator-based free tissue transfer. Further research is required to understand the flow dynamics of perforator flaps based on multiple perforators. However, surgeons should be cognizant that a single large perforator may have substantially higher flow rates than multiple small perforators. Routine FVI calculation is recommended to ensure complete flap survival. PMID:25426345

  3. A numerical study of blood flow using mixture theory

    PubMed Central

    Wu, Wei-Tao; Aubry, Nadine; Massoudi, Mehrdad; Kim, Jeongho; Antaki, James F.

    2014-01-01

    In this paper, we consider the two dimensional flow of blood in a rectangular microfluidic channel. We use Mixture Theory to treat this problem as a two-component system: One component is the red blood cells (RBCs) modeled as a generalized Reiner–Rivlin type fluid, which considers the effects of volume fraction (hematocrit) and influence of shear rate upon viscosity. The other component, plasma, is assumed to behave as a linear viscous fluid. A CFD solver based on OpenFOAM® was developed and employed to simulate a specific problem, namely blood flow in a two dimensional micro-channel, is studied. Finally to better understand this two-component flow system and the effects of the different parameters, the equations are made dimensionless and a parametric study is performed. PMID:24791016

  4. A numerical study of blood flow using mixture theory.

    PubMed

    Wu, Wei-Tao; Aubry, Nadine; Massoudi, Mehrdad; Kim, Jeongho; Antaki, James F

    2014-03-01

    In this paper, we consider the two dimensional flow of blood in a rectangular microfluidic channel. We use Mixture Theory to treat this problem as a two-component system: One component is the red blood cells (RBCs) modeled as a generalized Reiner-Rivlin type fluid, which considers the effects of volume fraction (hematocrit) and influence of shear rate upon viscosity. The other component, plasma, is assumed to behave as a linear viscous fluid. A CFD solver based on OpenFOAM(®) was developed and employed to simulate a specific problem, namely blood flow in a two dimensional micro-channel, is studied. Finally to better understand this two-component flow system and the effects of the different parameters, the equations are made dimensionless and a parametric study is performed. PMID:24791016

  5. Numerical Studies of a Fluidic Diverter for Flow Control

    NASA Technical Reports Server (NTRS)

    Gokoglu, Suleyman A.; Kuczmarski, Maria A.; Culley, Dennis E.; Raghu, Surya

    2009-01-01

    The internal flow structure in a specific fluidic diverter is studied over a range from low subsonic to sonic inlet conditions by a time-dependent numerical analysis. The understanding will aid in the development of fluidic diverters with minimum pressure losses and advanced designs of flow control actuators. The velocity, temperature and pressure fields are calculated for subsonic conditions and the self-induced oscillatory behavior of the flow is successfully predicted. The results of our numerical studies have excellent agreement with our experimental measurements of oscillation frequencies. The acoustic speed in the gaseous medium is determined to be a key factor for up to sonic conditions in governing the mechanism of initiating the oscillations as well as determining its frequency. The feasibility of employing plasma actuation with a minimal perturbation level is demonstrated in steady-state calculations to also produce oscillation frequencies of our own choosing instead of being dependent on the fixed-geometry fluidic device.

  6. SPECT study of regional cerebral blood flow in Alzheimer disease

    SciTech Connect

    Bonte, F.J.; Ross, E.D.; Chehabi, H.H.; Devous, M.D. Sr.

    1986-07-01

    A common cause of dementia in late midlife and old age is Alzheimer disease (AD), which affects more than one in 20 individuals over the age of 65. Past studies of regional cerebral blood flow (rCBF) in patients with AD here suggested blood flow abnormalities, but findings have differed. We have studied 37 patients diagnosed as having AD with inhalation and washout of /sup 133/Xe and single-photon emission computed tomography (SPECT), obtaining evidence of abnormal rCBF patterns in 19. Flow reductions were most common in the temporoparietal regions and were occasionally found in the frontal areas. Investigators using positron-emission tomography (PET) have identified similar findings with respect to rCBF and regional oxygen, glucose, and protein metabolism. The SPECT determination of rCBF, which gives information similar to that provided by PET, may assume importance in the diagnosis of AD and in the differential diagnosis of the dementias.

  7. Study on the numerical schemes for hypersonic flow simulation

    NASA Astrophysics Data System (ADS)

    Nagdewe, S. P.; Shevare, G. R.; Kim, Heuy-Dong

    2009-10-01

    Hypersonic flow is full of complex physical and chemical processes, hence its investigation needs careful analysis of existing schemes and choosing a suitable scheme or designing a brand new scheme. The present study deals with two numerical schemes Harten, Lax, and van Leer with Contact (HLLC) and advection upstream splitting method (AUSM) to effectively simulate hypersonic flow fields, and accurately predict shock waves with minimal diffusion. In present computations, hypersonic flows have been modeled as a system of hyperbolic equations with one additional equation for non-equilibrium energy and relaxing source terms. Real gas effects, which appear typically in hypersonic flows, have been simulated through energy relaxation method. HLLC and AUSM methods are modified to incorporate the conservation laws for non-equilibrium energy. Numerical implementation have shown that non-equilibrium energy convect with mass, and hence has no bearing on the basic numerical scheme. The numerical simulation carried out shows good comparison with experimental data available in literature. Both numerical schemes have shown identical results at equilibrium. Present study has demonstrated that real gas effects in hypersonic flows can be modeled through energy relaxation method along with either AUSM or HLLC numerical scheme.

  8. Studies on nonequilibrium phenomena in supersonic chemically reacting flows

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Chandrasekhar, Rajnish

    1993-01-01

    This study deals with a systematic investigation of nonequilibrium processes in supersonic combustion. The two-dimensional, elliptic Navier-Stokes equations are used to investigate supersonic flows with nonequilibrium chemistry and thermodynamics, coupled with radiation, for hydrogen-air systems. The explicit, unsplit MacCormack finite-difference scheme is used to advance the governing equations in time, until convergence is achieved. For a basic understanding of the flow physics, premixed flows undergoing finite rate chemical reactions are investigated. Results obtained for specific conditions indicate that the radiative interactions vary substantially, depending on reactions involving HO2 and NO species, and that this can have a noticeable influence on the flowfield. The second part of this study deals with premixed reacting flows under thermal nonequilibrium conditions. Here, the critical problem is coupling of the vibrational relaxation process with the radiative heat transfer. The specific problem considered is a premixed expanding flow in a supersonic nozzle. Results indicate the presence of nonequilibrium conditions in the expansion region of the nozzle. This results in reduction of the radiative interactions in the flowfield. Next, the present study focuses on investigation of non-premixed flows under chemical nonequilibrium conditions. In this case, the main problem is the coupled turbulence-chemistry interaction. The resulting formulation is validated by comparison with experimental data on reacting supersonic coflowing jets. Results indicate that the effect of heat release is to lower the turbulent shear stress and the mean density. The last part of this study proposes a new theoretical formulation for the coupled turbulence-radiation interactions. Results obtained for the coflowing jets experiment indicate that the effect of turbulence is to enhance the radiative interactions.

  9. Experimental flow-through study of artificial diagenesis in sandstones

    SciTech Connect

    Donahoe, R.J.; Leard, L.E.

    1986-05-01

    During petroleum reservoir development and production, various fluids are injected into well bores. Because these fluids differ compositionally from the reservoir rock pore fluids, induced fluid/rock interactions can range from none to extreme in their effect on reservoir rock properties. These induced reactions, considered artificial diagenesis, can be studied using a new low-temperature flow-through hydrothermal apparatus. The flow-through apparatus is presented as an alternative to conventional high-temperature, high-pressure permeameters for studying water/rock interactions. This equipment is designed to study water/rock interactions under variable fluid-flow rate (0.0005-10 ml/min), temperature (50/sup 0/-300/sup 0/C), and pressure (50-500 bar) conditions; to allow in-situ measurements of permeability; and to accommodate packed column or 1-in. diameter core samples. An experimental and computational study was conducted at 250/sup 0/C to investigate the effects of fluid flow rate, fluid composition, and sandstone mineralogy on disaggregated sandstone sample alteration mineralogy and permeability. Three series of flow-through experiments were conducted with the following variables: (1) sandstone composition (quartzarenite, 2 arkose); (2) fluid composition (distilled, deionized water and aqueous solutions of HF/HCl and NaOH); and (3) fluid-flow rate (0.001-1 ml/min). Preliminary results from these experiments are presented. The variables listed above are discussed in terms of their effect on sandstone alteration mineralogy and permeability. In addition, computer chemical-equilibrium programs used to model these man-made diagenetic systems are evaluated.

  10. Studies of granular flow down an inclined chute. Final technical report

    SciTech Connect

    Hanes, D.M.

    1996-06-01

    An inclined chute facility and its associated diagnostics has been developed and utilized to study the flow of granular materials. A variety of flow regimes and flow phenomena were observed. Fully developed flows were observed over a bumpy base for a range of slopes. Under some conditions, these flows were dominated by friction and under other conditions, collisions played a dominant role. A variety of unsteady flows were also observed. These include decelerating flows, accelerating flows, and wavy (periodic) flows. The characteristics of the base strongly influenced the flow regime and flow dynamics.

  11. Monitoring Particulate Matter with Commodity Hardware

    NASA Astrophysics Data System (ADS)

    Holstius, David

    Health effects attributed to outdoor fine particulate matter (PM 2.5) rank it among the risk factors with the highest health burdens in the world, annually accounting for over 3.2 million premature deaths and over 76 million lost disability-adjusted life years. Existing PM2.5 monitoring infrastructure cannot, however, be used to resolve variations in ambient PM2.5 concentrations with adequate spatial and temporal density, or with adequate coverage of human time-activity patterns, such that the needs of modern exposure science and control can be met. Small, inexpensive, and portable devices, relying on newly available off-the-shelf sensors, may facilitate the creation of PM2.5 datasets with improved resolution and coverage, especially if many such devices can be deployed concurrently with low system cost. Datasets generated with such technology could be used to overcome many important problems associated with exposure misclassification in air pollution epidemiology. Chapter 2 presents an epidemiological study of PM2.5 that used data from ambient monitoring stations in the Los Angeles basin to observe a decrease of 6.1 g (95% CI: 3.5, 8.7) in population mean birthweight following in utero exposure to the Southern California wildfires of 2003, but was otherwise limited by the sparsity of the empirical basis for exposure assessment. Chapter 3 demonstrates technical potential for remedying PM2.5 monitoring deficiencies, beginning with the generation of low-cost yet useful estimates of hourly and daily PM2.5 concentrations at a regulatory monitoring site. The context (an urban neighborhood proximate to a major goods-movement corridor) and the method (an off-the-shelf sensor costing approximately USD $10, combined with other low-cost, open-source, readily available hardware) were selected to have special significance among researchers and practitioners affiliated with contemporary communities of practice in public health and citizen science. As operationalized by

  12. Study of flow through a bowl mill model

    SciTech Connect

    Murty, G.V.R.; Babu, U.S.

    1998-07-01

    Bowl Mills are used in Thermal Power plants for pulverizing the raw coal, while drying, to the required fineness and achieve the desired combustion efficiency in the boiler. The Indian coals contain high ash content (some times as high as 60%) and as such the primary air has to handle media of different density namely the coal and the quartz. In this context, the distribution of air in the mill plays a significant role in the lifting of particles from the mill. The wear on the rotating components is increased through repetitive grinding because of improper distribution of air within the mill. Reduction of wear and enhancement of life of mill internals including the rotating components is a continuing goal and few more studies have been carried out in this direction. One such study is the replacement of rotating vane wheel and deflector in the separator body with an air guide ring and air diversion plate. Model studies have been carried out by traversing a five hole prove at different locations within the mill to study the distribution of flow as a result of this modification. The variation of absolute velocity and the associated flow direction has been calculated to describe the flow structure within the mill. The results are presented in non dimensional form to draw suitable conclusions. The present study indicated the possibility of improvement in the distribution of flow within the mill with increased magnitude of velocity at different locations.

  13. Determine the optimal carrier selection for a logistics network based on multi-commodity reliability criterion

    NASA Astrophysics Data System (ADS)

    Lin, Yi-Kuei; Yeh, Cheng-Ta

    2013-05-01

    From the perspective of supply chain management, the selected carrier plays an important role in freight delivery. This article proposes a new criterion of multi-commodity reliability and optimises the carrier selection based on such a criterion for logistics networks with routes and nodes, over which multiple commodities are delivered. Carrier selection concerns the selection of exactly one carrier to deliver freight on each route. The capacity of each carrier has several available values associated with a probability distribution, since some of a carrier's capacity may be reserved for various orders. Therefore, the logistics network, given any carrier selection, is a multi-commodity multi-state logistics network. Multi-commodity reliability is defined as a probability that the logistics network can satisfy a customer's demand for various commodities, and is a performance indicator for freight delivery. To solve this problem, this study proposes an optimisation algorithm that integrates genetic algorithm, minimal paths and Recursive Sum of Disjoint Products. A practical example in which multi-sized LCD monitors are delivered from China to Germany is considered to illustrate the solution procedure.

  14. Ultrasonic Studies and Microchannel Flow Behavior of Copper Oxide Nanofluid

    NASA Astrophysics Data System (ADS)

    Rashin, M. Nabeel; Hemalatha, J.; Nalini, R. Pratibha; Ramya, A. V.

    2011-07-01

    Stable suspensions of nanosized copper oxide nanoparticles in Ethylene glycol are prepared at various concentrations through ultrasonically assisted sol gel method. The structural studies are made through X-ray diffraction technique and the nanoparticle-fluid interaction studies are made through acoustical technique. The molecular interaction is studied as a function of concentration and temperature. The flow behaviors of nanofluids of various concentrations are investigated using the circular and rectangular microchannels of various diameters.

  15. Grid resolution study of ground water flow and transport.

    PubMed

    Bower, Kathleen M; Gable, Carl W; Zyvoloski, George A

    2005-01-01

    Three-dimensional grids representing a heterogeneous, ground water system are generated at 10 different resolutions in support of a site-scale flow and transport modeling effort. These grids represent hydrostratigraphy near Yucca Mountain, Nevada, consisting of 18 stratigraphic units with contrasting fluid flow and transport properties. The grid generation method allows the stratigraphy to be modeled by numerical grids of different resolution so that comparison studies can be performed to test for grid quality and determine the resolution required to resolve geologic structure and physical processes such as fluid flow and solute transport. The process of generating numerical grids with appropriate property distributions from geologic conceptual models is automated, thus making the entire process easy to implement with fewer user-induced errors. The series of grids of various resolutions are used to assess the level at which increasing resolution no longer influences the flow and solute transport results. Grid resolution is found to be a critical issue for ground water flow and solute transport. The resolution required in a particular instance is a function of the feature size of the model, the intrinsic properties of materials, the specific physics of the problem, and boundary conditions. The asymptotic nature of results related to flow and transport indicate that for a hydrologic model of the heterogeneous hydrostratigraphy under Yucca Mountain, a horizontal grid spacing of 600 m and vertical grid spacing of 40 m resolve the hydrostratigraphic model with sufficient precision to accurately model the hypothetical flow and solute transport to within 5% of the value that would be obtained with much higher resolution. PMID:15726930

  16. Experimental study of vortex breakdown in a cylindrical, swirling flow

    NASA Technical Reports Server (NTRS)

    Stevens, J. L.; Celik, Z. Z.; Cantwell, B. J.; Lopez, J. M.

    1996-01-01

    The stability of a steady, vortical flow in a cylindrical container with one rotating endwall has been experimentally examined to gain insight into the process of vortex breakdowwn. The dynamics of the flow are governed by the Reynolds number (Re) and the aspect ratio of the cylinder. Re is given by Omega R(sup 2)/nu, where Omega is the speed of rotation of the endwall, R is the cylinder radius, and nu is the kinematic viscosity of the fluid filling the cylinder. The aspect ratio is H/R, where H is the height of the cylinder. Numerical simulation studies disagree whether or not the steady breakdown is stable beyond a critical Reynolds number, Re(sub c). Previous experimental researches have considered the steady and unsteady flows near Re(sub c), but have not explored the stability of the steady breakdown structures beyond this value. In this investigation, laser induced fluorescence was utilized to observe both steady and unsteady vortex breakdown at a fixed H/R of 2.5 with Re varying around Re(sub c). When the Re of a steady flow was slowly increased beyond Re(sub c), the breakdown structure remained steady even though unsteadiness was possible. In addition, a number of hysteresis events involving the oscillation periods of the unsteady flow were noted. The results show that both steady and unsteady vortex breakdown occur for a limited range of Re above Re(sub c). Also, with increasing Re, complex flow transformations take place that alter the period at which the unsteady flow oscillates.

  17. 5 CFR 1315.13 - Commodity Credit Corporation payments.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 3 2013-01-01 2013-01-01 false Commodity Credit Corporation payments... PAYMENT § 1315.13 Commodity Credit Corporation payments. As provided in § 1315.1(d), the provisions of... Credit Corporation (CCC) pursuant to Section 4(h) of the Act of June 29, 1948 (15 U.S.C. 714b(h))...

  18. 5 CFR 1315.13 - Commodity Credit Corporation payments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 3 2012-01-01 2012-01-01 false Commodity Credit Corporation payments... PAYMENT § 1315.13 Commodity Credit Corporation payments. As provided in § 1315.1(d), the provisions of... Credit Corporation (CCC) pursuant to Section 4(h) of the Act of June 29, 1948 (15 U.S.C. 714b(h))...

  19. 46 CFR 531.10 - Excepted and exempted commodities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... NSAs for the movement of the following, as defined in section 3 of the Act (46 U.S.C. 40102) and § 530... filing NSAs which exclusively concern the commodities or services listed in paragraph (a) or (b) of this section. (2) NSAs filed with the Commission may include the commodities or services listed in paragraph...

  20. 46 CFR 531.10 - Excepted and exempted commodities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... NSAs for the movement of the following, as defined in section 3 of the Act (46 U.S.C. 40102) and § 530... filing NSAs which exclusively concern the commodities or services listed in paragraph (a) or (b) of this section. (2) NSAs filed with the Commission may include the commodities or services listed in paragraph...

  1. 46 CFR 531.10 - Excepted and exempted commodities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    .... NSAs for the movement of the following, as defined in section 3 of the Act (46 U.S.C. 40102) and § 530... filing NSAs which exclusively concern the commodities or services listed in paragraph (a) or (b) of this section. (2) NSAs filed with the Commission may include the commodities or services listed in paragraph...

  2. 46 CFR 531.10 - Excepted and exempted commodities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... NSAs for the movement of the following, as defined in section 3 of the Act (46 U.S.C. 40102) and § 530... filing NSAs which exclusively concern the commodities or services listed in paragraph (a) or (b) of this section. (2) NSAs filed with the Commission may include the commodities or services listed in paragraph...

  3. 46 CFR 531.10 - Excepted and exempted commodities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    .... NSAs for the movement of the following, as defined in section 3 of the Act (46 U.S.C. 40102) and § 530... filing NSAs which exclusively concern the commodities or services listed in paragraph (a) or (b) of this section. (2) NSAs filed with the Commission may include the commodities or services listed in paragraph...

  4. 5 CFR 1315.13 - Commodity Credit Corporation payments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 3 2011-01-01 2011-01-01 false Commodity Credit Corporation payments... PAYMENT § 1315.13 Commodity Credit Corporation payments. As provided in § 1315.1(d), the provisions of... Credit Corporation (CCC) pursuant to Section 4(h) of the Act of June 29, 1948 (15 U.S.C. 714b(h))...

  5. 7 CFR 1493.5 - Criteria for agricultural commodity allocations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Criteria for agricultural commodity allocations. 1493... agricultural commodity allocations. The criteria considered by CCC in reviewing proposals for specific U.S... development, expansion or maintenance of the market in the importing country for the particular...

  6. 7 CFR 1493.5 - Criteria for agricultural commodity allocations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Criteria for agricultural commodity allocations. 1493.5 Section 1493.5 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS CCC EXPORT CREDIT GUARANTEE PROGRAMS Restrictions and Criteria...

  7. 31 CFR 560.526 - Commodities trading and related transactions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Commodities trading and related transactions. 560.526 Section 560.526 Money and Finance: Treasury Regulations Relating to Money and Finance... Licenses, Authorizations and Statements of Licensing Policy § 560.526 Commodities trading and...

  8. 31 CFR 560.526 - Commodities trading and related transactions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Commodities trading and related transactions. 560.526 Section 560.526 Money and Finance: Treasury Regulations Relating to Money and Finance... Licenses, Authorizations and Statements of Licensing Policy § 560.526 Commodities trading and...

  9. 7 CFR 1599.8 - Entry and handling of commodities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Entry and handling of commodities. 1599.8 Section 1599.8 Agriculture Regulations of the Department of Agriculture (Continued) FOREIGN AGRICULTURAL SERVICE, DEPARTMENT OF AGRICULTURE McGOVERN-DOLE INTERNATIONAL FOOD FOR EDUCATION AND CHILD NUTRITION PROGRAM § 1599.8 Entry and handling of commodities....

  10. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... commodities. 51-6.4 Section 51-6.4 Public Contracts and Property Management Other Provisions Relating to... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale... overseas, to designated depots at ports of embarkation. Zone pricing is used for delivery to Alaska...

  11. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... commodities. 51-6.4 Section 51-6.4 Public Contracts and Property Management Other Provisions Relating to... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale... overseas, to designated depots at ports of embarkation. Zone pricing is used for delivery to Alaska...

  12. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... commodities. 51-6.4 Section 51-6.4 Public Contracts and Property Management Other Provisions Relating to... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale... overseas, to designated depots at ports of embarkation. Zone pricing is used for delivery to Alaska...

  13. 5 CFR 1315.13 - Commodity Credit Corporation payments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Commodity Credit Corporation payments... PAYMENT § 1315.13 Commodity Credit Corporation payments. As provided in § 1315.1(d), the provisions of this part apply to payments relating to the procurement of property and services made by the...

  14. 12 CFR 211.603 - Commodity swap transactions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Commodity swap transactions. 211.603 Section 211.603 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM... Commodity swap transactions. For text of interpretation relating to this subject, see § 208.128 of...

  15. 7 CFR 253.10 - Commodity control, storage and distribution.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Section 253.10 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION...-condition commodities. The State agency shall immediately notify the appropriate Food and Nutrition Service... commodities are declared unfit for human consumption in accordance with § 250.13(f) of this chapter,...

  16. 7 CFR 1425.17 - Eligible commodity and pooling.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS COOPERATIVE MARKETING ASSOCIATIONS § 1425.17... marketing proceeds from the commodity in accordance with § 1425.18; and (5) Members agreed to accept a... the CMA for the quantity of a farm-stored commodity that is, pursuant to such CMA marketing...

  17. 22 CFR 211.6 - Processing, repackaging, and labeling commodities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Processing, repackaging, and labeling commodities. 211.6 Section 211.6 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT TRANSFER OF FOOD COMMODITIES FOR FOOD USE IN DISASTER RELIEF, ECONOMIC DEVELOPMENT AND OTHER ASSISTANCE § 211.6...

  18. 22 CFR 211.6 - Processing, repackaging, and labeling commodities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Processing, repackaging, and labeling commodities. 211.6 Section 211.6 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT TRANSFER OF FOOD COMMODITIES FOR FOOD USE IN DISASTER RELIEF, ECONOMIC DEVELOPMENT AND OTHER ASSISTANCE § 211.6...

  19. 22 CFR 211.6 - Processing, repackaging, and labeling commodities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Processing, repackaging, and labeling commodities. 211.6 Section 211.6 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT TRANSFER OF FOOD COMMODITIES FOR FOOD USE IN DISASTER RELIEF, ECONOMIC DEVELOPMENT AND OTHER ASSISTANCE § 211.6...

  20. 7 CFR 247.28 - Storage and inventory of commodities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 247.28 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS COMMODITY SUPPLEMENTAL FOOD PROGRAM § 247.28 Storage and... must provide for storage of commodities that protects them from theft, spoilage, damage or...

  1. 7 CFR 247.28 - Storage and inventory of commodities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 247.28 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS COMMODITY SUPPLEMENTAL FOOD PROGRAM § 247.28 Storage and... must provide for storage of commodities that protects them from theft, spoilage, damage or...

  2. 15 CFR 740.18 - Agricultural commodities (AGR).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 2 2013-01-01 2013-01-01 false Agricultural commodities (AGR). 740.18 Section 740.18 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS LICENSE EXCEPTIONS § 740.18 Agricultural commodities...

  3. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Military resale... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale commodities are available from the central nonprofit agencies. Authorized resale outlets (military...

  4. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Military resale... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale commodities are available from the central nonprofit agencies. Authorized resale outlets (military...

  5. 15 CFR 740.18 - Agricultural commodities (AGR).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false Agricultural commodities (AGR). 740.18 Section 740.18 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS LICENSE EXCEPTIONS § 740.18 Agricultural commodities...

  6. 15 CFR 740.18 - Agricultural commodities (AGR).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Agricultural commodities (AGR). 740.18 Section 740.18 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS LICENSE EXCEPTIONS § 740.18 Agricultural commodities...

  7. 31 CFR 560.526 - Commodities trading and related transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... by United States persons in commodities of U.S. or third-country origin destined for Iran or the... transactions. (a) Trading in Iranian-origin commodities. With respect to § 560.206, specific licenses may be... Iranian-origin goods, or transactions incidental to such trading, where: (1) No party to the...

  8. 22 CFR 228.11 - Source and origin of commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... source and origin of a commodity as defined in § 228.01 shall be a country or countries authorized in the... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Source and origin of commodities. 228.11 Section 228.11 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES ON SOURCE, ORIGIN...

  9. 7 CFR 253.10 - Commodity control, storage and distribution.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 4 2013-01-01 2013-01-01 false Commodity control, storage and distribution. 253.10... THE FOOD DISTRIBUTION PROGRAM FOR HOUSEHOLDS ON INDIAN RESERVATIONS § 253.10 Commodity control, storage and distribution. (a) Control and accountability. The State agency shall be responsible for...

  10. Study of Unsteady Flows with Concave Wall Effect

    NASA Technical Reports Server (NTRS)

    Wang, Chi R.

    2003-01-01

    This paper presents computational fluid dynamic studies of the inlet turbulence and wall curvature effects on the flow steadiness at near wall surface locations in boundary layer flows. The time-stepping RANS numerical solver of the NASA Glenn-HT RANS code and a one-equation turbulence model, with a uniform inlet turbulence modeling level of the order of 10 percent of molecular viscosity, were used to perform the numerical computations. The approach was first calibrated for its predictabilities of friction factor, velocity, and temperature at near surface locations within a transitional boundary layer over concave wall. The approach was then used to predict the velocity and friction factor variations in a boundary layer recovering from concave curvature. As time iteration proceeded in the computations, the computed friction factors converged to their values from existing experiments. The computed friction factors, velocity, and static temperatures at near wall surface locations oscillated periodically in terms of time iteration steps and physical locations along the span-wise direction. At the upstream stations, the relationship among the normal and tangential velocities showed vortices effects on the velocity variations. Coherent vortices effect on the velocity components broke down at downstream stations. The computations also predicted the vortices effects on the velocity variations within a boundary layer flow developed along a concave wall surface with a downstream recovery flat wall surface. It was concluded that the computational approach might have the potential to analyze the flow steadiness in a turbine blade flow.

  11. Experimental study of fluid flows in a precessing cylindrical annulus

    NASA Astrophysics Data System (ADS)

    Lin, Yufeng; Noir, Jerome; Jackson, Andrew

    2014-04-01

    The flow inside a precessing fluid cavity has been given particular attention since the end of the 19th century in geophysical and industrial contexts. The present study aims at shedding light on the underlying mechanism by which the flow inside a precessing cylindrical annulus transitions from laminar to multiple scale complex structures. We address this problem experimentally using ultrasonic Doppler velocimetry to diagnose the fluid velocity in a rotating and precessing cylindrical annulus. When precession is weak, the flow can be described as a superposition of forced inertial modes. Above a critical value of the precession rate, the forced flow couples with two free inertial modes satisfying triadic resonance conditions, leading to the classical growth and collapse. Using a Bayesian approach, we extract the wavenumber, frequency, growth rate, and amplitude of each mode involved in the instability. In some cases, we observe for the first time ever experimentally two pairs of free modes coexisting with the forced flow. At larger precession rates, we do not observe triadic resonance any more, instead we observe several harmonics whose frequencies are integer multiples of the rotation frequency.

  12. Fluid flow and heat convection studies for actively cooled airframes

    NASA Technical Reports Server (NTRS)

    Mills, A. F.

    1992-01-01

    The work done during the progress report period from May-October 1992 is summarized. The effect of wall thermal boundary conditions on flows over a step or rib when repeated rib roughness is used for heating augmentation is examined. In numerical investigations of various such laminar and turbulent flows, the local heat transfer coefficients on a forward-facing step or on a rib were found to be very sensitive to the wall thermal boundary condition. For the computation of constant property laminar flow, the wall thermal boundary conditions were either a uniform heat flux or a uniform temperature. Results (Nusselt number and isotherms) of the studies are included. The second part of the work consisted of using PHOENICS to solve the conjugate heat transfer problem of flow over a rib in channel. Finally, the algebraic stress model in the TEAM (Turbulent Elliptic Algorithm-Manchester) code was tested for jet impingement flow, but there needs to be an addition of the energy equation to the code.

  13. Duct flow nonuniformities study for space shuttle main engine

    NASA Technical Reports Server (NTRS)

    Thoenes, J.

    1985-01-01

    To improve the Space Shuttle Main Engine (SSME) design and for future use in the development of generation rocket engines, a combined experimental/analytical study was undertaken with the goals of first, establishing an experimental data base for the flow conditions in the SSME high pressure fuel turbopump (HPFTP) hot gas manifold (HGM) and, second, setting up a computer model of the SSME HGM flow field. Using the test data to verify the computer model it should be possible in the future to computationally scan contemplated advanced design configurations and limit costly testing to the most promising design. The effort of establishing and using the computer model is detailed. The comparison of computational results and experimental data observed clearly demonstrate that computational fluid mechanics (CFD) techniques can be used successfully to predict the gross features of three dimensional fluid flow through configurations as intricate as the SSME turbopump hot gas manifold.

  14. Systematic study of plasma flow during plasma sheet thinnings

    NASA Technical Reports Server (NTRS)

    Lui, A. T. Y.; Frank, L. A.; Ackerson, K. L.; Meng, C.-I.; Akasofu, S.-I.

    1977-01-01

    On the basis of a study of Imp 6 measurements of plasma flow, it is concluded that there is no clear indication of a predominance of tailward plasma flow beyond about X = -15 R sub E in the midnight sector of the plasma sheet during the expansive phase of a substorm. In fact, it is shown statistically that sunward plasma flow is more frequently observed in the midnight sector within about 30 R sub E from the earth than in any other direction during plasma sheet thinning at the substorm expansion. This result supports the conclusion that there is no definite evidence for the formation of a reconnection neutral line in the near-earth plasma sheet during most substorms.

  15. Low Reynolds Number Nozzle Flow Study. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Whalen, Margaret V.

    1987-01-01

    An experimental study of low Reynolds number nozzle flow was performed. A brief comparison was made between some of the experimental performance data and performance predicted by a viscous flow code. The performance of 15, 20, and 25 deg conical nozzles, bell nozzles, and trumpet nozzles was evaluated with unheated nitrogen and hydrogen. The numerical analysis was applied to the conical nozzles only, using an existing viscous flow code that was based on a slender-channel approximation. Although the trumpet and 25 deg conical nozzles had slightly better performance at lower Reynolds numbers, it is unclear which nozzle is superior as all fell within the experimental error band. The numerical rssults were found to agree with experimental results for nitrogen and for some of the hydrogen data. Some code modification is recommended to improve confidence in the performance prediction.

  16. Commodity-Based Computing Clusters at PPPL.

    NASA Astrophysics Data System (ADS)

    Wah, Darren; Davis, Steven L.; Johansson, Marques; Klasky, Scott; Tang, William; Valeo, Ernest

    2002-11-01

    In order to cost-effectively facilitate mid-scale serial and parallel computations and code development, a number of commodity-based clusters have been built at PPPL. A recent addition is the PETREL cluster, consisting of 100 dual-processor machines, both Intel and AMD, interconnected by a 100Mbit switch. Sixteen machines have an additional Myrinet 2000 interconnect. Also underway is the implementation of a Prototype Topical Computing Facility which will explore the effectiveness and scaling of cluster computing for larger scale fusion codes, specifically including those being developed under the SCIDAC auspices. This facility will consist of two parts: a 64 dual-processor node cluster, with high speed interconnect, and a 16 dual-processor node cluster, utilizing gigabit networking, built for the purpose of exploring grid-enabled computing. The initial grid explorations will be in collaboration with the Princeton University Institute for Computational Science and Engineering (PICSciE), where a 16 processor cluster dedicated to investigation of grid computing is being built. The initial objectives are to (1) grid-enable the GTC code and an MHD code, making use of MPICH-G2 and (2) implement grid-enabled interactive visualization using DXMPI and the Chromium API.

  17. Live HDR video streaming on commodity hardware

    NASA Astrophysics Data System (ADS)

    McNamee, Joshua; Hatchett, Jonathan; Debattista, Kurt; Chalmers, Alan

    2015-09-01

    High Dynamic Range (HDR) video provides a step change in viewing experience, for example the ability to clearly see the soccer ball when it is kicked from the shadow of the stadium into sunshine. To achieve the full potential of HDR video, so-called true HDR, it is crucial that all the dynamic range that was captured is delivered to the display device and tone mapping is confined only to the display. Furthermore, to ensure widespread uptake of HDR imaging, it should be low cost and available on commodity hardware. This paper describes an end-to-end HDR pipeline for capturing, encoding and streaming high-definition HDR video in real-time using off-the-shelf components. All the lighting that is captured by HDR-enabled consumer cameras is delivered via the pipeline to any display, including HDR displays and even mobile devices with minimum latency. The system thus provides an integrated HDR video pipeline that includes everything from capture to post-production, archival and storage, compression, transmission, and display.

  18. Commodity chemical growth to slow in 1993

    SciTech Connect

    Plishner, E.S.

    1992-12-09

    In their latest chemical outlook, DRI/McGraw-Hill economists characterize 1992 as a peak year for U.S. commodity chemical demand growth, at 4.2%, tapering off to a compound 2.2% between 1993 and 1995. Just as operating rates begin to reach higher levels in 1995, however, DRI forecasts slowing GNP growth. DRI's Ramunas J. Svarcas expects a decline in exports. Those plastics promising the rosiest consumption outlook include melamine-formaldehyde resin, up 9.9% in 1992, from 155 million lbs in 1991, and projected to grow 8.6%/year through 1995; styrene acrylonitrile resin, up 23% this year, from 58 million lbs last year, and growing 8.2%/year through 1995; and unsaturated polyester, up 11.7% this year, from 1.07 billion lbs in 1991, and increasing at 6.5%/year. Methanol is a bright spot, with consumption growing 4.7%, from 11.2 billion lbs in 1991 and 12%/year thereafter. Ortho-xylene managed an impressive 21% rebound from a depressed 1991 level of 783 million lbs, and is expected to continue its recovery at 7.7%/year.

  19. Features of the Java commodity grid kit.

    SciTech Connect

    von Laszewski, G.; Gawor, J.; Lane, P.; Rehn, N.; Russell, M.; Mathematics and Computer Science

    2002-11-01

    In this paper we report on the features of the Java Commodity Grid Kit (Java CoG Kit). The Java CoG Kit provides middleware for accessing Grid functionality from the Java framework. Java CoG Kit middleware is general enough to design a variety of advanced Grid applications with quite different user requirements. Access to the Grid is established via Globus Toolkit protocols, allowing the Java CoG Kit to also communicate with the services distributed as part of the C Globus Toolkit reference implementation. Thus, the Java CoG Kit provides Grid developers with the ability to utilize the Grid, as well as numerous additional libraries and frameworks developed by the Java community to enable network, Internet, enterprise and peer-to-peer computing. A variety of projects have successfully used the client libraries of the Java CoG Kit to access Grids driven by the C Globus Toolkit software. In this paper we also report on the efforts to develop serverside Java CoG Kit components. As part of this research we have implemented a prototype pure Java resource management system that enables one to run Grid jobs on platforms on which a Java virtual machine is supported, including Windows NT machines.

  20. Experimental study of the influence of flow passage subtle variation on mixed-flow pump performance

    NASA Astrophysics Data System (ADS)

    Bing, Hao; Cao, Shuliang

    2014-05-01

    In the mixed-flow pump design, the shape of the flow passage can directly affect the flow capacity and the internal flow, thus influencing hydraulic performance, cavitation performance and operation stability of the mixed-flow pump. However, there is currently a lack of experimental research on the influence mechanism. Therefore, in order to analyze the effects of subtle variations of the flow passage on the mixed-flow pump performance, the frustum cone surface of the end part of inlet contraction flow passage of the mixed-flow pump is processed into a cylindrical surface and a test rig is built to carry out the hydraulic performance experiment. In this experiment, parameters, such as the head, the efficiency, and the shaft power, are measured, and the pressure fluctuation and the noise signal are also collected. The research results suggest that after processing the inlet flow passage, the head of the mixed-flow pump significantly goes down; the best efficiency of the mixed-flow pump drops by approximately 1.5%, the efficiency decreases more significantly under the large flow rate; the shaft power slightly increases under the large flow rate, slightly decreases under the small flow rate. In addition, the pressure fluctuation amplitudes on both the impeller inlet and the diffuser outlet increase significantly with more drastic pressure fluctuations and significantly lower stability of the internal flow of the mixed-flow pump. At the same time, the noise dramatically increases. Overall speaking, the subtle variation of the inlet flow passage leads to a significant change of the mixed-flow pump performance, thus suggesting a special attention to the optimization of flow passage. This paper investigates the influence of the flow passage variation on the mixed-flow pump performance by experiment, which will benefit the optimal design of the flow passage of the mixed-flow pump.

  1. Experimental Study of the Flow in a Rotating CVD Reactor

    NASA Astrophysics Data System (ADS)

    Wong, Sun; Meng, Jiandong; Jaluria, Yogesh

    2013-11-01

    An experimental model is developed to study the rotating, vertical, impinging chemical vapor deposition reactor. Deposition occurs only when the system has enough thermal energy. Therefore, understanding the fluid flow and thermal characteristics of the system would provide a good basis to model the thin film deposition process. The growth rate and the uniformity of the film are the two most important factors in the CVD process and these depend strongly on the flow and the thermal transport within the system. Operating parameters, such as inflow velocity, susceptor temperature and rotational speed, are used to create different design simulations. Fluid velocities and temperature distributions are recorded to obtain the effects of different operating parameters. Velocities are recorded by using a rotameter and a hot wire anemometer. The temperatures are recorded by using thermocouples and an infrared thermometer. The effects of buoyancy and rotation are examined. The expermental study is also coupled with a numerical study for validation of the numerical model and to expand the domain. Comparisons between the two models are presented, indicating fair agreement. The numerical model also includes simulation of Gallium Nitride (GaN) thin film deposition. This simulation thus includes mass transport and gas kinetics, along with the flow and heat transfer within the system. A three dimensional simulation is needed due to the rotation of the susceptor. The results obtained as well as the underlying fluid flow phenomena are discussed.

  2. A detailed study of mean-flow solutions for stability analysis of transitional flows

    NASA Technical Reports Server (NTRS)

    Ramakrishnan, R.; Vatsa, V.; Otto, J.; Kumar, A.

    1993-01-01

    A finite-volume upwind-difference parabolized Navier-Stokes code is utilized to obtain laminar mean-flow solutions at Mach 3.5 on a half-angle cone of 5 deg at an angle-of-attack of 2 deg. A detailed study is conducted on this configuration; the main focus is the velocity profiles in the leeward and windward symmetry planes at various axial locations. Comparisons of the solution profiles are made with both a central-difference code that incorporates scalar and matrix dissipation models and another state-of-the-art upwind-difference finitevolume code. The results obtained emphasize the importance of using matrix dissipation models for schemes that require explicit artificial dissipation. These results also illustrate the accuracy and efficiency of the planeby-plane marching procedure for computing mean-flow solutions for predicting the onset of transition with linear instability.

  3. Doppler study of the peripheral flows in early gestation.

    PubMed

    Wloch, A; Sodowski, K; Rozmus-Warcholinska, W; Wloch, S; Bodzek, P; Czuba, B; Borowski, D; Cnota, W; Kuka, D; Szaflik, K; Huhta, J

    2008-09-01

    The aim of this study was to determine the first trimester human peripheral arterial and venous blood flow between 5 - 10 weeks of gestation. Two hundred twenty four women with singleton, uncomplicated pregnancies were prospectively studied with transvaginal ultrasound. Ductus venosus, umbilical artery waveforms and pulsatility indexes (PI) were assessed as well as the waveform of the umbilical vein and the mean velocity (V(mean)) of the umbilical artery flow. The heart rate was also obtained and analyzed. The fetal heart rate showed a positive correlation with increasing gestational age R=0.76 (p<0.000001). Recordings from the umbilical artery, umbilical vein and ductus venosus were obtained starting from 7 weeks of gestation. The signal from the ductus venosus presented always as antegrade flow during atrial contractions. The pulsatility index (PI) of DV as well as PI of the umbilical artery remained unchanged during the study (statistically non-significant). The umbilical artery, using Doppler tracing was investigated and an absent diastolic flow was documented in every case. Umbilical artery V(mean) increased from 3.8 + 0.32 cm/s to 9.0 + 0.21 cm/s from 7 to 10 weeks of gestation (p< 0.005). Recordings from the umbilical vein showed the pulsation during atrial contractions. Ductus venosus blood velocity and waveform patterns did not change significantly during the study period. Pulsation in the umbilical vein is a typical Doppler finding at the embryonic time. Placental volume blood flow increased significantly with no change in the placental vascular impedance. PMID:18955756

  4. Couette flows of a granular monolayer: An experimental study

    SciTech Connect

    Elliott, K.E.; Ahmadi, G.; Kvasnak, W.

    1995-03-01

    An experimental study concerning rapid flows of granular materials in a two dimensional planar granular Couette flow apparatus is performed. The device is capable of generating particulate flows in grain-inertia regime at different shearing rates and solid volume fractions. Multi-color spherical glass particles are sheared across an annular test-section for several wall angular velocities. A video recorder is used to record the motion of particles, and consecutive images are stored and analyzed by an image processing technique for evaluating individual grain velocities. Experimental data for the mean velocity, the root mean-square fluctuation velocity components and the solid volume fraction profile are obtained. The resulting mean velocity profiles have a roughly linear variation for the range of solid volume fractions and shear rates studied. The solid volume fraction profiles exhibit nonuniform variations with the highest concentration occuring near the center of the shearing cell. The RMS-fluctuation velocities are roughly constant, with the streamwise fluctuation being somewhat larger than the cross-stream direction. The experimentally measured flow properties are in reasonable agreement with the earlier theoretical and simulation results.

  5. Fundamental Study of Material Flow in Friction Stir Welds

    NASA Technical Reports Server (NTRS)

    Reynolds, Anthony P.

    1999-01-01

    The presented research project consists of two major parts. First, the material flow in solid-state, friction stir, butt-welds as been investigated using a marker insert technique. Changes in material flow due to welding parameter as well as tool geometry variations have been examined for different materials. The method provides a semi-quantitative, three-dimensional view of the material transport in the welded zone. Second, a FSW process model has been developed. The fully coupled model is based on fluid mechanics; the solid-state material transport during welding is treated as a laminar, viscous flow of a non-Newtonian fluid past a rotating circular cylinder. The heat necessary for the material softening is generated by deformation of the material. As a first step, a two-dimensional model, which contains only the pin of the FSW tool, has been created to test the suitability of the modeling approach and to perform parametric studies of the boundary conditions. The material flow visualization experiments agree very well with the predicted flow field. Accordingly, material within the pin diameter is transported only in the rotation direction around the pin. Due to the simplifying assumptions inherent in the 2-D model, other experimental data such as forces on the pin, torque, and weld energy cannot be directly used for validation. However, the 2-D model predicts the same trends as shown in the experiments. The model also predicts a deviation from the "normal" material flow at certain combinations of welding parameters, suggesting a possible mechanism for the occurrence of some typical FSW defects. The next step has been the development of a three-dimensional process model. The simplified FSW tool has been designed as a flat shoulder rotating on the top of the workpiece and a rotating, cylindrical pin, which extends throughout the total height of the flow domain. The thermal boundary conditions at the tool and at the contact area to the backing plate have been varied

  6. 17 CFR 32.4 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Fraud in connection with commodity option transactions. 32.4 Section 32.4 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.4 Fraud in connection with...

  7. 17 CFR 32.4 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Fraud in connection with commodity option transactions. 32.4 Section 32.4 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.4 Fraud in connection with...

  8. 17 CFR 33.10 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 1 2012-04-01 2012-04-01 false Fraud in connection with commodity option transactions. 33.10 Section 33.10 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF DOMESTIC EXCHANGE-TRADED COMMODITY OPTION TRANSACTIONS § 33.10 Fraud...

  9. 17 CFR 32.9 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 1 2012-04-01 2012-04-01 false Fraud in connection with commodity option transactions. 32.9 Section 32.9 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.9 Fraud in connection with...

  10. 17 CFR 3.10 - Registration of futures commission merchants, introducing brokers, commodity trading advisors...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Registration of futures commission merchants, introducing brokers, commodity trading advisors, commodity pool operators and leverage transaction merchants. 3.10 Section 3.10 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGISTRATION Registration §...

  11. 17 CFR 32.12 - Exemption from suspension of commodity option transactions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Exemption from suspension of commodity option transactions. 32.12 Section 32.12 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.12 Exemption from suspension...

  12. 22 CFR 201.42 - Reexport of USAID-financed commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Reexport of USAID-financed commodities. 201.42... COMMODITY TRANSACTIONS FINANCED BY USAID General Provisions Relating to USAID Financing of Commodities and Commodity-Related Services § 201.42 Reexport of USAID-financed commodities. Unless specifically...

  13. 17 CFR 37.4 - Election to trade excluded and exempt commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Election to trade excluded and exempt commodities. 37.4 Section 37.4 Commodity and Securities Exchanges COMMODITY FUTURES TRADING... commodities. A board of trade that is or elects to become a registered derivatives transaction...

  14. 17 CFR 33.10 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Fraud in connection with commodity option transactions. 33.10 Section 33.10 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF DOMESTIC EXCHANGE-TRADED COMMODITY OPTION TRANSACTIONS § 33.10 Fraud...

  15. 17 CFR 32.9 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 1 2011-04-01 2011-04-01 false Fraud in connection with commodity option transactions. 32.9 Section 32.9 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.9 Fraud in connection with...

  16. 17 CFR 32.9 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Fraud in connection with commodity option transactions. 32.9 Section 32.9 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF COMMODITY OPTION TRANSACTIONS § 32.9 Fraud in connection with...

  17. 17 CFR 33.10 - Fraud in connection with commodity option transactions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 1 2011-04-01 2011-04-01 false Fraud in connection with commodity option transactions. 33.10 Section 33.10 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF DOMESTIC EXCHANGE-TRADED COMMODITY OPTION TRANSACTIONS § 33.10 Fraud...

  18. Dynamics of Diffusion Flames in von Karman Swirling Flows Studied

    NASA Technical Reports Server (NTRS)

    Nayagam, Vedha; Williams, Forman A.

    2002-01-01

    Von Karman swirling flow is generated by the viscous pumping action of a solid disk spinning in a quiescent fluid media. When this spinning disk is ignited in an oxidizing environment, a flat diffusion flame is established adjacent to the disk, embedded in the boundary layer (see the preceding illustration). For this geometry, the conservation equations reduce to a system of ordinary differential equations, enabling researchers to carry out detailed theoretical models to study the effects of varying strain on the dynamics of diffusion flames. Experimentally, the spinning disk burner provides an ideal configuration to precisely control the strain rates over a wide range. Our original motivation at the NASA Glenn Research Center to study these flames arose from a need to understand the flammability characteristics of solid fuels in microgravity where slow, subbuoyant flows can exist, producing very small strain rates. In a recent work (ref. 1), we showed that the flammability boundaries are wider and the minimum oxygen index (below which flames cannot be sustained) is lower for the von Karman flow configuration in comparison to a stagnation-point flow. Adding a small forced convection to the swirling flow pushes the flame into regions of higher strain and, thereby, decreases the range of flammable strain rates. Experiments using downward facing, polymethylmethacrylate (PMMA) disks spinning in air revealed that, close to the extinction boundaries, the flat diffusion flame breaks up into rotating spiral flames (refs. 2 and 3). Remarkably, the dynamics of these spiral flame edges exhibit a number of similarities to spirals observed in biological systems, such as the electric pulses in cardiac muscles and the aggregation of slime-mold amoeba. The tail of the spiral rotates rigidly while the tip executes a compound, meandering motion sometimes observed in Belousov-Zhabotinskii reactions.

  19. Numerical simulation studies of unsteady low Reynolds number separated flows

    NASA Astrophysics Data System (ADS)

    Tatineni, Mahidhar

    Numerical simulations were used to study unsteady low-Reynolds-number separated flows. The studies were focused on the instability of the separation bubbles, the associated vortex shedding, and the response to imposed disturbances. The simulations were performed for separation bubbles in both low Mach number compressible and incompressible flow regimes. The compressible study consisted of unsteady simulations of flows over the Eppler 387 airfoil and the APEX airfoil. For a sufficiently high Reynolds number the simulations showed that the flow over the airfoils is inherently unsteady, with associated vortex shedding. A Fourier analysis of the unsteady flowfield revealed the presence of a dominant frequency in the flow. The dominant frequency from the numerical solution was found to agree with the most unstable frequency calculated using linear stability theory. The vortex shedding was shown to be caused by the growth of the disturbance waves corresponding to the dominant mode calculated from the linear stability analysis. In order to study the separation bubble and the vortex shedding in detail, a simpler two-dimensional (2-D) and three-dimensional (3-D) incompressible flow over a flat plate was considered. The onset of self excited vortex shedding, and the response of the separation bubble to 2-D and 3-D disturbances was studied in detail through numerical simulations. The incompressible Navier-Stokes equations were solved using a fifth order finite difference scheme for spatial discretization and a fourth order Runge-Kutta scheme for time advancement. A new high-order nonuniform grid finite difference scheme was also developed for the simulations. The incompressible simulation results showed that it was possible to induce vortex shedding by imposing disturbances upstream of the separation bubble. For a sufficiently large freestream velocity gradient the separation bubble was globally unstable, leading to a growth in the size of the separation bubble and the

  20. Global flows of critical metals necessary for low-carbon technologies: the case of neodymium, cobalt, and platinum.

    PubMed

    Nansai, Keisuke; Nakajima, Kenichi; Kagawa, Shigemi; Kondo, Yasushi; Suh, Sangwon; Shigetomi, Yosuke; Oshita, Yuko

    2014-01-01

    This study, encompassing 231 countries and regions, quantifies the global transfer of three critical metals (neodymium, cobalt, and platinum) considered vital for low-carbon technologies by means of material flow analysis (MFA), using trade data (BACI) and the metal contents of trade commodities, resolving the optimization problem to ensure the material balance of the metals within each country and region. The study shows that in 2005 international trade led to global flows of 18.6 kt of neodymium, 154 kt of cobalt, and 402 t of platinum and identifies the main commodities and top 50 bilateral trade links embodying these metals. To explore the issue of consumption efficiency, the flows were characterized according to the technological level of each country or region and divided into three types: green ("efficient use"), yellow ("moderately efficient use"), and red ("inefficient use"). On this basis, the shares of green, yellow, and red flows in the aggregate global flow of Nd were found to be 1.2%, 98%, and 1.2%, respectively. For Co, the respective figures are 53%, 28%, and 19%, and for Pt 15%, 84%, and 0.87%. Furthermore, a simple indicator focusing on the composition of the three colored flows for each commodity was developed to identify trade commodities that should be prioritized for urgent technical improvement to reduce wasteful use of the metals. Based on the indicator, we discuss logical, strategic identification of the responsibilities and roles of the countries involved in the global flows. PMID:24387330

  1. Study of the crevicular fluid flow rate in smokers.

    PubMed

    Rosa, G M; Lucas, G Q; Lucas, O N

    2000-01-01

    The purpose of this study was to investigate if smoking--a risk factor in periodontal disease-affects the crevicular fluid (CF) flow rate. Twenty-nine dental students were included in the control group--non-smokers- (NS) and 34 in the experimental group--smokers- (S). All subjects were enrolled in a rigorous dental hygiene program (RDHP). The Greene-Vermillion plaque index, and Löe-Silness gingival index (GI) were recorded. CF was obtained and measured with the Periotron 8000. These recordings were made before and after the RDHP. The results show that the CF mean flow rate was slightly lower in the S group than in the NS group, for both recordings. The analysis of the relation between the CF flow rate and the GI recorded in the dental surfaces, revealed a significantly lower flow rate in the S group for GI 1 (p < 0.01) and GI 3 (p < 0.05). The difference observed between the S and NS groups, may be due to the vasoconstrictor action of the cigarette components (nicotine and/or metabolites) on the gingival vasculature. PMID:11885468

  2. Aspect ratio effects in turbulent duct flows studied with DNS

    NASA Astrophysics Data System (ADS)

    Vinuesa, R.; Noorani, A.; Lozano-Durán, A.; Schlatter, P.; Fischer, P.; Nagib, H.

    2012-11-01

    Three-dimensional effects present in turbulent duct flows, i.e., side-wall boundary layers and secondary motions, are studied by means of direct numerical simulations (DNS). The spectral element code Nek5000, developed by Fischer et. al. (2008), is used to compute turbulent duct flows with aspect ratios 1 and 3 in streamwise-periodic boxes of length 25 h (long enough to capture the longest streamwise structures). The total number of grid points is 28 and 62 million respectively, and the inflow conditions were adjusted iteratively in order to keep the same bulk Reynolds number at the centerplane (Reb , c = 2800) in both cases. Spanwise variations in wall shear, mean-flow profiles and turbulence statistics were analyzed with aspect ratio, and also compared with the 2D channel. The simulations were started from a laminar duct profile, and transition to turbulence was triggered by means of trip-forcing in the wall-normal direction, applied at the two horizontal walls. In addition, we developed a convergence criterion aimed at assessing the necessary averaging time TA for converged statistics. We find that econdary motions present in duct flows require longer averaging times and the total shear-stress profile is not necessarily linear.

  3. An analytical study of reduced-gravity flow dynamics

    NASA Technical Reports Server (NTRS)

    Bradshaw, R. D.; Kramer, J. L.; Zich, J. L.

    1976-01-01

    Addition of surface tension forces to a marker-and-cell code and the performance of four incompressible fluid simulations in reduced gravity, were studied. This marker-and-cell code has a variable grid capability with arbitrary curved boundaries and time dependent acceleration fields. The surface tension logic includes a spline fit of surface marker particles as well as contact angle logic for straight and curved wall boundaries. Three types of flow motion were simulated with the improved code: impulsive settling in a model Centaur LH2 tank, continuous settling in a model and full scale Centaur LO2 tank and mixing in a Centaur LH2 tank. The impulsive settling case confirmed a drop tower analysis which indicated more orderly fluid collection flow patterns with this method providing a potential savings in settling propellants. In the LO2 tank, fluid collection and flow simulation into the thrust barrel were achieved. The mixing simulation produced good results indicating both the development of the flow field and fluid interface behavior.

  4. Study of blood flow sensing with microwave radiometry

    NASA Technical Reports Server (NTRS)

    Porter, R. A.; Wentz, F. J., III

    1973-01-01

    A study and experimental investigation has been performed to determine the feasibility of measuring regional blood flow and volume in man by means of microwave radiometry. An indication was expected of regional blood flow from measurement of surface and subsurface temperatures with a sensitive radiometer. Following theoretical modeling of biological tissue, to determine the optimum operating frequency for adequate sensing depth, a sensitive microwave radiometer was designed for operation at 793 MHz. A temperature sensitivity of of 0.06 K rms was realized in this equipment. Measurements performed on phantom tissue models, consisting of beef fat and lean beefsteak showed that the radiometer was capable of sensing temperatures from a depth between 3.8 and 5.1 cm. Radiometric and thermodynamic temperature measurements were also performed on the hind thighs of large dogs. These showed that the radiometer could sense subsurface temperatures from a depth of, at least, 1.3 cm. Delays caused by externally-generated RF interference, coupled with the lack of reliable blood flow measurement equipment, prevented correlation of radiometer readings with reginal blood flow. For the same reasons, it was not possible to extend the radiometric observations to human subjects.

  5. Numerical study of chemically reacting flows using an LU scheme

    NASA Technical Reports Server (NTRS)

    Shuen, Jian Shun; Yoon, Seokkwan

    1988-01-01

    A new computational fluid dynamic code has been developed for the study of mixing and chemical reactions in the flow fields of ramjets and scramjets. The code employs an implicit finite volume, lower-upper symmetric successive overrelaxation scheme for solving the complete two-dimensional Navier-Stokes equations and species transport equations in a fully-coupled and very efficient manner. The combustion processes are modeled by an 8-species, 14-step finite rate chemistry model whereas turbulence is simulated by a Baldwin-Lomax algebraic model. The validity of the code is demonstrated by comparing the numerical calculations with both experimental data and previous calculations of a cold flow helium injection into a straight channel and premixed hydrogen-air reacting flows in a ramped duct. The code is then used to calculate the mixing and chemical reactions of a hydrogen jet transversely injected into a supersonic airstream. Results are presented describing the flow field, the recirculation regions in front and behind the injector, and the chemical reactions.

  6. Integration of flow studies for robust selection of mechanoresponsive genes.

    PubMed

    Maimari, Nataly; Pedrigi, Ryan M; Russo, Alessandra; Broda, Krysia; Krams, Rob

    2016-03-01

    Blood flow is an essential contributor to plaque growth, composition and initiation. It is sensed by endothelial cells, which react to blood flow by expressing > 1000 genes. The sheer number of genes implies that one needs genomic techniques to unravel their response in disease. Individual genomic studies have been performed but lack sufficient power to identify subtle changes in gene expression. In this study, we investigated whether a systematic meta-analysis of available microarray studies can improve their consistency. We identified 17 studies using microarrays, of which six were performed in vivo and 11 in vitro. The in vivo studies were disregarded due to the lack of the shear profile. Of the in vitro studies, a cross-platform integration of human studies (HUVECs in flow cells) showed high concordance (> 90 %). The human data set identified > 1600 genes to be shear responsive, more than any other study and in this gene set all known mechanosensitive genes and pathways were present. A detailed network analysis indicated a power distribution (e. g. the presence of hubs), without a hierarchical organisation. The average cluster coefficient was high and further analysis indicated an aggregation of 3 and 4 element motifs, indicating a high prevalence of feedback and feed forward loops, similar to prokaryotic cells. In conclusion, this initial study presented a novel method to integrate human-based mechanosensitive studies to increase its power. The robust network was large, contained all known mechanosensitive pathways and its structure revealed hubs, and a large aggregate of feedback and feed forward loops. PMID:26842798

  7. Exploratory study of the effects of injection configurations and inlet flow conditions on the characteristics of flow in spherical chambers

    NASA Technical Reports Server (NTRS)

    Johnson, B. V.

    1972-01-01

    Flow visualization studies were conducted to evaluate techniques for injecting simulated-fuel and simulated-propellant gases into a spherical cavity for application to open-cycle gaseous-core nuclear rockets. Preliminary studies were conducted with six simulated-fuel injectors and eight simulated-propellant injection configurations. Additional tests were conducted with the best configuration to determine the effect of weight-flow ratio, gas density ratio, injector location, and flow distribution on the simulated-fuel containment characteristics.

  8. Study of Subsonic Flow Over a TOW 2B Missile

    NASA Astrophysics Data System (ADS)

    Goudarzi, Koorosh; Jamali, Mehdi

    2016-01-01

    The objective of this investigation is to study the subsonic flow over a missile. In this paper, a model of TOW 2B missile is studied. Two computational approaches are being explored, namely solutions based on the Reynolds-averaged compressible Navier-Stokes equations and solutions based on the inviscid flow (small disturbance theory). The simulations are performed at the Mach number of 0.6, 0.7, 0.8, 0.9 and 1.0 at four angles of attack of 2, 4, 6 and 8 degree. Results obtained from analytical simulation are compared with numerical data. It is found that lift and drag coefficients would go up by increasing of the angle of attack and the Mach number. Trend of changes of the results that obtained from the small disturbance theory is roughly as same as the numeric solution.

  9. A static data flow simulation study at Ames Research Center

    NASA Technical Reports Server (NTRS)

    Barszcz, Eric; Howard, Lauri S.

    1987-01-01

    Demands in computational power, particularly in the area of computational fluid dynamics (CFD), led NASA Ames Research Center to study advanced computer architectures. One architecture being studied is the static data flow architecture based on research done by Jack B. Dennis at MIT. To improve understanding of this architecture, a static data flow simulator, written in Pascal, has been implemented for use on a Cray X-MP/48. A matrix multiply and a two-dimensional fast Fourier transform (FFT), two algorithms used in CFD work at Ames, have been run on the simulator. Execution times can vary by a factor of more than 2 depending on the partitioning method used to assign instructions to processing elements. Service time for matching tokens has proved to be a major bottleneck. Loop control and array address calculation overhead can double the execution time. The best sustained MFLOPS rates were less than 50% of the maximum capability of the machine.

  10. A Study on the Air flow outside Ambient Vaporizer Fin

    NASA Astrophysics Data System (ADS)

    Oh, G.; Lee, T.; Jeong, H.; Chung, H.

    2015-09-01

    In this study, we interpreted Fog's Fluid that appear in the Ambient Vaporizer and predict the point of change Air to Fog. We interpreted using Analysis working fluid was applied to LNG and Air. We predict air flow when there is chill of LNG in the air Temperature and that makes fog. Also, we interpreted based on Summer and Winter criteria in the air temperature respectively. Finally, we can check the speed of the fog when fog excreted.

  11. Numerical study of Reynolds stress in compressible flows

    NASA Technical Reports Server (NTRS)

    Vandromme, D.; Hamin, H.

    1985-01-01

    A second order closure has been implemented in an implicit Navier-Stokes solver to study the behavior of the Reynolds stresses under the influence of severe pressure gradients. In the boundary layer zone, the strongly sheared character of the mean flow dominates the turbulence generation mechanisms. However, the pressure gradients also play a very important role for these processes, but at different locations within the boundary layer.

  12. Fundamental Study on the Segmented Flow Injection - Multiphase Flow Formation Towards Microchip-Based Multi-Ion Sensing

    NASA Astrophysics Data System (ADS)

    Hisamoto, Hideaki; Horiuchi, Takayuki; Hibara, Akihide; Tokeshi, Manabu; Kitamori, Takehiko

    A new fluid flow inside the microchannel was successfully developed. The flow created here involves segmented flow injection of plural organic phases into a microchannel followed by contact with a single aqueous phase to form stable organic-aqueous two-layer flow inside the microchannel. Fundamental study on the developed flow inside the microchannel was performed by monitoring the dye-doped segmented organic phases by thermal lens microscopy (TLM). Excellent repeatability and very small injection volume in developing segmented flow were realized. The new fluid flow created here is expected to allow us multi-ion sensing, which is not easily demonstrated by conventional ion sensor technology using a solvent polymeric membrane, by combining with neutral ionophore-based ion pair extraction using plural numbers of organic phases containing different ionophore molecules.

  13. Voluntary Medical Male Circumcision: Logistics, Commodities, and Waste Management Requirements for Scale-Up of Services

    PubMed Central

    Edgil, Dianna; Stankard, Petra; Forsythe, Steven; Rech, Dino; Chrouser, Kristin; Adamu, Tigistu; Sakallah, Sameer; Thomas, Anne Goldzier; Albertini, Jennifer; Stanton, David; Dickson, Kim Eva; Njeuhmeli, Emmanuel

    2011-01-01

    Background The global HIV prevention community is implementing voluntary medical male circumcision (VMMC) programs across eastern and southern Africa, with a goal of reaching 80% coverage in adult males by 2015. Successful implementation will depend on the accessibility of commodities essential for VMMC programming and the appropriate allocation of resources to support the VMMC supply chain. For this, the United States President’s Emergency Plan for AIDS Relief, in collaboration with the World Health Organization and the Joint United Nations Programme on HIV/AIDS, has developed a standard list of commodities for VMMC programs. Methods and Findings This list of commodities was used to inform program planning for a 1-y program to circumcise 152,000 adult men in Swaziland. During this process, additional key commodities were identified, expanding the standard list to include commodities for waste management, HIV counseling and testing, and the treatment of sexually transmitted infections. The approximate costs for the procurement of commodities, management of a supply chain, and waste disposal, were determined for the VMMC program in Swaziland using current market prices of goods and services. Previous costing studies of VMMC programs did not capture supply chain costs, nor the full range of commodities needed for VMMC program implementation or waste management. Our calculations indicate that depending upon the volume of services provided, supply chain and waste management, including commodities and associated labor, contribute between US$58.92 and US$73.57 to the cost of performing one adult male circumcision in Swaziland. Conclusions Experience with the VMMC program in Swaziland indicates that supply chain and waste management add approximately US$60 per circumcision, nearly doubling the total per procedure cost estimated previously; these additional costs are used to inform the estimate of per procedure costs modeled by Njeuhmeli et al. in “Voluntary Medical

  14. Program Evaluation: Food Stamps and Commodity Distribution in Rural Areas of Central Pennsylvania.

    ERIC Educational Resources Information Center

    Madden J. Patrick; Yoder, Marion D.

    Since one primary goal of the Commodity Distribution (CD) Program and the Food Stamp (FS) Program is to improve diets of low-income families, this 1969-70 study focused on whether the adequacy of a low-income family's dietary intake was improved by their participation in a food-assistance program. As stated, the adequacy of a family's dietary…

  15. Delay Discounting of Self-Determined and Experimenter-Determined Commodities

    ERIC Educational Resources Information Center

    Weatherly, Jeffrey N.; Gudding, Jennifer; Derenne, Adam

    2010-01-01

    Research suggests that individuals prefer self-determined reinforcers over experimenter-determined ones. The present study had 518 college students complete a delay-discounting task in which the commodity was cigarettes, a grocery store gift card, casino tokens, cash, or the choice of the four. The least amount of delay discounting was observed…

  16. FEASIBILITY OF PRODUCING COMMODITIES AND ELECTRICITY FOR SPACE SHUTTLE OPERATIONS AT VANDENBERG AIR FORCE BASE

    EPA Science Inventory

    The report gives results of a preliminary screening study of the technical and economic feasibility of the on-site production of commodities (liquid propellant and gases) and electricity to support space shuttle launch activities at Vandenberg Air Force Base (VAFB). Both commerci...

  17. Experimental study of choking flow of water at supercritical conditions

    NASA Astrophysics Data System (ADS)

    Muftuoglu, Altan

    Future nuclear reactors will operate at a coolant pressure close to 25 MPa and at outlet temperatures ranging from 500°C to 625°C. As a result, the outlet flow enthalpy in future Supercritical Water-Cooled Reactors (SCWR) will be much higher than those of actual ones which can increase overall nuclear plant efficiencies up to 48%. However, under such flow conditions, the thermal-hydraulic behavior of supercritical water is not fully known, e.g., pressure drop, forced convection and heat transfer deterioration, critical and blowdown flow rate, etc. Up to now, only a very limited number of studies have been performed under supercritical conditions. Moreover, these studies are conducted at conditions that are not representative of future SCWRs. In addition, existing choked flow data have been collected from experiments at atmospheric discharge pressure conditions and in most cases by using working fluids different than water which constrain researchers to analyze the data correctly. In particular, the knowledge of critical (choked) discharge of supercritical fluids is mandatory to perform nuclear reactor safety analyses and to design key mechanical components (e.g., control and safety relief valves, etc.). Hence, an experimental supercritical water facility has been built at Ecole Polytechnique de Montreal which allows researchers to perform choking flow experiments under supercritical conditions. The facility can also be used to carry out heat transfer and pressure drop experiments under supercritical conditions. In this thesis, we present the results obtained at this facility using a test section that contains a 1 mm inside diameter, 3.17 mm long orifice plate with sharp edges. Thus, 545 choking flow of water data points are obtained under supercritical conditions for flow pressures ranging from 22.1 MPa to 32.1 MPa, flow temperatures ranging from 50°C to 502°C and for discharge pressures from 0.1 MPa to 3.6 MPa. Obtained data are compared with the data given in

  18. Flow distribution and maximum current density studies in redox flow batteries with a single passage of the serpentine flow channel

    NASA Astrophysics Data System (ADS)

    Ke, Xinyou; Alexander, J. Iwan D.; Prahl, Joseph M.; Savinell, Robert F.

    2014-12-01

    Flow batteries show promise for very large-scale stationary energy storage such as needed for the grid and renewable energy implementation. In recent years, researchers and developers of redox flow batteries (RFBs) have found that electrode and flow field designs of PEM fuel cell (PEMFC) technology can increase the power density and consequently push down the cost of flow battery stacks. In this paper we present a macroscopic model of a typical PEMFC-like RFB electrode-flow field design. The model is a layered system comprised of a single passage of a serpentine flow channel and a parallel underlying porous electrode (or porous layer). The effects of the inlet volumetric flow rate, permeability of the porous layer, thickness of the porous layer and thickness of the flow channel on the flow penetration into the porous layer are investigated. The maximum current density corresponding to stoichiometry is estimated to be 377 mA cm-2 and 724 mA cm-2, which compares favorably with experiments of ∼400 mA cm-2 and ∼750 mA cm-2, for a single layer and three layers of the carbon fiber paper, respectively.

  19. 76 FR 12072 - Public Availability of Commodity Futures Trading Commission FY 2010 Service Contract Inventory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-04

    ... From the Federal Register Online via the Government Publishing Office COMMODITY FUTURES TRADING COMMISSION Public Availability of Commodity Futures Trading Commission FY 2010 Service Contract Inventory AGENCY: Commodity Futures Trading Commission. ACTION: Notice of Public Availability of FY 2010...

  20. 77 FR 7138 - Public Availability of Commodity Futures Trading Commission FY 2011 Service Contract Inventory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ... From the Federal Register Online via the Government Publishing Office COMMODITY FUTURES TRADING COMMISSION Public Availability of Commodity Futures Trading Commission FY 2011 Service Contract Inventory AGENCY: Commodity Futures Trading Commission. ACTION: Notice of Public Availability of FY 2011...

  1. Study of vortex flows of dust particles in a plasma

    NASA Astrophysics Data System (ADS)

    Chai, Kil-Byoung; Marshall, Ryan; Bellan, Paul

    2015-11-01

    Vortex motion of dust particles in a plasma has been studied both theoretically and experimentally. In the theoretical study, the ion drag force acting on the dust particle is found to be non-conservative and to have a finite curl because the gradient of |ui|and the gradient of ni are not parallel. The finite curl of the ion drag force acts as a source of vorticity; kinematic viscosity dissipates the generated vorticity. We confirm that vortex flows of micron size dust grains are observed where finite curls of the ion drag force are expected to exist in the Caltech ice dusty plasma experiment. The direction and velocity of the vortex flows are in good agreement with the values predicted by our model. We also found that vortex motion is only observed when the ion density exceeds a threshold value. Above the threshold value, the observed vorticity increases as the ion density increases as predicted by the theory. These observations support the conclusion that the vortex flows in the experiment result from the finite curl of the ion drag force (i.e., non-conservative force).

  2. Study of He II boiling flow field around a heater

    NASA Astrophysics Data System (ADS)

    Murakami, M.; Takada, S.; Nozawa, M.

    2015-12-01

    We studied boiling phenomena in He II based on the flow velocity measurement data by using a PIV (Particle Image Velocimeter). Noisy and silent film boiling modes together with non-boiling state were generated on/around a horizontal planar or a cylindrical heater. For PIV tracer particles, we used H2-D2 solid particles that were neutrally buoyant in He II. Video images showing the development and collapse of vapour bubble or film and the motions of tracer particles were PIV-analysed. We found the PIV velocity field was composed of AC and DC velocity components of the normal fluid. The AC component follows the dynamic behaviour of vapour, and the DC results primarily from the thermal counter flow and secondarily is induced by the asymmetric vapour bubble motion. We also investigated unsteady velocity component. The objective of this series of study is to compare the characteristic features of the flow field of He II film boiling states and peculiar He I boiling state in He II and to make clear the difference in the heat transfer performance of each boiling mode.

  3. Experimental study of phase separation in dividing two phase flow

    SciTech Connect

    Qian Yong; Yang Zhilin; Xu Jijun

    1996-12-31

    Experimental study of phase separation of air-water two phase bubbly, slug flow in the horizontal T-junction is carried out. The influences of the inlet mass quality X1, mass extraction rate G3/G1, and fraction of extracted liquid QL3/QL1 on phase separation characteristics are analyzed. For the first time, the authors have found and defined pulsating run effect by the visual experiments, which show that under certain conditions, the down stream flow of the T-junction has strangely affected the phase redistribution of the junction, and firstly point out that the downstream geometric condition is very important to the study of phase separation phenomenon of two-phase flow in a T-junction. This kind of phenomenon has many applications in the field of energy, power, petroleum and chemical industries, such as the loss of coolant accident (LOCA) caused by a small break in a horizontal coolant pipe in nuclear reactor, and the flip-flop effect in the natural gas transportation pipeline system, etc.

  4. Numerical and experimental study of rotating jet flows

    NASA Astrophysics Data System (ADS)

    Shin, Seungwon; Che, Zhizhao; Kahouadji, Lyes; Matar, Omar; Chergui, Jalel; Juric, Damir

    2015-11-01

    Rotating jets are investigated through experimental measurements and numerical simulations. The experiments are performed on a rotating jet rig and the effects of a range of parameters controlling the liquid jet are investigated, e.g. jet flow rate, rotation speed, jet diameter, etc. Different regimes of the jet morphology are identified, and the dependence on several dimensionless numbers is studied, e.g. Reynolds number, Weber number, etc. The breakup process of droplets is visualized through high speed imaging. Full three-dimensional direct numerical simulations are performed using BLUE, a massively parallel two-phase flow code. The novel interface algorithms in BLUE track the gas-liquid interface through a wide dynamic range including ligament formation, break up and rupture. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  5. Theoretical study of aerodynamic characteristics of wings having vortex flow

    NASA Technical Reports Server (NTRS)

    Reddy, C. S.

    1979-01-01

    The aerodynamic characteristics of slender wings having separation induced vortex flows are investigated by employing three different computer codes--free vortex sheet, quasi vortex lattice, and suction analogy methods. Their capabilities and limitations are examined, and modifications are discussed. Flat wings of different configurations: arrow, delta, and diamond shapes, as well as cambered delta wings, are studied. The effect of notch ratio on the load distributions and the longitudinal characteristics of a family of arrow and diamond wings is explored. The sectional lift coefficients and the accumulated span loadings are determined for an arrow wing and are seen to be unusual in comparison with the attached flow results. The theoretically predicted results are compared with the existing experimental values.

  6. Study of fractal aperture distribution and flow in fractures

    SciTech Connect

    Kumar, S.; Zimmerman, R.W.; Bodvarsson, G.S.

    1990-01-01

    This study examines the roughness profiles and aperture distributions of fractures and faults by using concepts from fractal geometry. Simple models of flow of fluid in rough fractures are also discussed. A deterministic fractal representation of the roughness profile is presented which is shown to have many distinct advantages over other numerical methods, such as information compression, uniqueness and repeatability of surface simulation, retention of statistical information, and self-similarity over many scales. Also the fractal representation enables an isotropic surface and an aperture distribution to be simulated by examining a measured profile. Saturated fluid flow in fractures is then computed using a combined Navier-Stokes and Darcy equation. 14 refs., 5 figs.

  7. A study of two phase flow in fracture networks

    SciTech Connect

    Karasaki, K.; Pruess, K.; Vomvoris, S.; Segan, S.

    1994-12-31

    Accurate characterization of the two-phase flow behavior of the fractured rock mass is vital to the safety of a potential high level nuclear waste repository in the unsaturated, fractured welded tuff at Yucca Mountain, NV. A tool for studying the two-phase flow properties of a fracture networks was developed. It is based on a simple mechanistic model in which the capillary pressure of a fracture is a unique function of the aperture. Whether a particular fracture element is occupied by wetting fluid or non-wetting fluid is determined by allowability and accessibility criteria. Relative permeability characteristics of a simulated fracture network were investigated using the model. Different assumptions are examined regarding the interactions between phases. In all cases, strong phase interference was observed. Hysteresis effects and irreducible saturation were also explained based on the model.

  8. Basic study on hot-wire flow meter in forced flow of liquid hydrogen

    NASA Astrophysics Data System (ADS)

    Oura, Y.; Shirai, Y.; Shiotsu, M.; Murakami, K.; Tatsumoto, H.; Naruo, Y.; Nonaka, S.; Kobayashi, H.; Inatani, Y.; Narita, N.

    2014-01-01

    Liquid hydrogen (LH2) is a key issue in a carbon-free energy infrastructure at the energy storage and transportation stage. The typical features of LH2 are low viscosity, large latent heat and small density, compared with other general liquids. It is necessary to measure a mass flow of liquid hydrogen with a simple and compact method, especially in a two phase separate flow condition. We have proposed applying a hot-wire type flow meter, which is usually used a for gas flow meter, to LH2 flow due to the quite low viscosity and density. A test model of a compact LH2 hot-wire flow meter to measure local flow velocities near and around an inside perimeter of a horizontal tube by resistance thermometry was designed and made. The model flow meter consists of two thin heater wires made of manganin fixed in a 10 mm-diameter and 40 mm-length tube flow path made of GFRP. Each rigid heater wire was set twisted by 90 degrees from the inlet to the outlet along the inner wall. In other words, the wires were aslant with regard to the LH2 stream line. The heated wire was cooled by flowing LH2, and the flow velocity was obtained by means of the difference of the cooling characteristic in response to the flow velocity. In this report, we show results on the basic experiments with the model LH2 hot-wire flow meter. First, the heat transfer characteristics of the two heater wires for several LH2 flow velocities were measured. Second, the heating current was controlled to keep the wire temperature constant for various flow velocities. The relations between the flow velocity and the heating current were measured. The feasibility of the proposed model was confirmed.

  9. Study of asymmetric supersonic jet flow for ejectors

    SciTech Connect

    Ho, C.M. . Dept. of Aerospace Engineering); Knoke, G.S. ); Geller, E.W.; Liu, H.T. ); Jou, W.H. ); Chen, F.C.; Murphy, R.W. )

    1990-01-01

    An asymmetric subsonic jet nozzle with a small aspect ratio can entrain a mass several times higher than a circular jet can entrain in a low subsonic flow. In this study, we extend the Mach number of the jet to 2.5. The advantage an asymmetric jet has over a circular jet in enhancing mass transfer still exists in the supersonic range. The main objective of this study is to explore the possibility of applying the asymmetric jet to a supersonic ejector with pressure build-up. The wall confinement was found to have a strong effect on the entrainment.

  10. Aircraft energy efficiency laminar flow control wing design study

    NASA Technical Reports Server (NTRS)

    Bonner, T. F., Jr.; Pride, J. D., Jr.; Fernald, W. W.

    1977-01-01

    An engineering design study was performed in which laminar flow control (LFC) was integrated into the wing of a commercial passenger transport aircraft. A baseline aircraft configuration was selected and the wing geometry was defined. The LFC system, with suction slots, ducting, and suction pumps was integrated with the wing structure. The use of standard aluminum technology and advanced superplastic formed diffusion bonded titanium technology was evaluated. The results of the design study show that the LFC system can be integrated with the wing structure to provide a structurally and aerodynamically efficient wing for a commercial transport aircraft.

  11. Flow visualization study of the MOD-2 wind turbine wake

    SciTech Connect

    Liu H.T.; Waite, J.W.; Hiester, T.R.; Tacheron, P.H.; Srnsky, R.A.

    1983-06-01

    The specific objectives of the study reported were: to determine the geometry of the MOD-2 wind turbine wake in terms of wake height and width as a function of downstream distance under two conditions of atmospheric stability; to estimate the mean velocity deficit at several downstream stations in the turbine wake; and to investigate the behavior of the rotor-generated vortices, particularly their configuration and persistence. The background of the wake problem is briefly examined, including a discussion of the critical issues that the flow visualization study addresses. Experimental techniques and data analysis methods are described in detail. (LEW)

  12. U.S. Agricultural Commodity Statistics--Current Series.

    ERIC Educational Resources Information Center

    Murdock, J. Larry

    1988-01-01

    The author lists 43 current series produced by the United States Department of Agriculture. These publications contain information on agriculture commodity statistics and many can be borrowed from Regional Depository Libraries. (CH)

  13. Ambient flow studies and particulate collection measurements: A laminar flow, reduced entrainment electrostatic precipitator

    SciTech Connect

    Greiner, G.P.; Furlong, D.A.; Bahner, M.A.

    1989-05-01

    This report describes ambient temperature testing of an electrostatic precipitator having a portion of the main precipitator flow drawn through porous (fabric) plates. The effects of flow through the plates (side flow) on precipitator turbulence and particulate removal efficiency are investigated. Ambient temperature particulate removal efficiency measurements are conducted on both indoor air dust, and on injected coal fly ash. 24 figs., 10 tabs.

  14. Ranking and selection of motor carrier safety performance by commodity.

    PubMed

    Horrace, William C; Keane, Thomas P

    2004-11-01

    We use recent safety performance data to rank US motor carrier commodity segments (e.g., Tank segment or Produce segment) in terms of several driver-related, vehicle-related, and crash-related safety measures. Ranking and selection inference techniques are used to determine the best and worst performing commodity segments at the 95% confidence level. The results are mixed, however the Passenger segment is generally best, while the Produce, Intermodal, and Refrigerated segments tend to be worst. PMID:15350872

  15. Experimental study of static flow instability in subcooled flow boiling in parallel channels

    SciTech Connect

    Siman-Tov, M.; Felde, D.K.; McDuffee, J.L.; Yoder, G.L.

    1995-12-31

    Experimental data for static flow instability or flow excursion (FE) at conditions applicable to the Advanced Neutron Source Reactor are very limited. A series of FE tests with light water flowing vertically upward was completed covering a local exit heat flux range of 0.7--18 MW/m{sup 2}, exit velocity range of 2.8--28.4 m/s, exit pressure range of 0.117--1.7 MPa, and inlet temperature range of 40-- 50{degrees}C. Most of the tests were performed in a ``stiff`` (constant flow) system where the instability threshold was detected through the minimum of the pressure-drop curve. A few tests were also conducted using as ``soft`` (constant pressure drop) a system as possible to secure a true FE phenomenon (actual secondary burnout). True critical heat flux experiments under similar conditions were also conducted using a stiff system. The FE data reported in this study considerably extend the velocity range of data presently available worldwide, most of which were obtained at velocities below 10 m/s. The Saha and Zuber correlation had the best fit with the data out of the three correlations compared. However, a modification was necessary to take into account the demonstrated dependence of the St and Nu numbers on subcooling levels, especially in the low subcooling regime. Comparison of Thermal Hydraulic Test Loop (THTL) data, as well as extensive data from other investigators, led to a proposed modification to the Saha and Zuber correlation for onset of significant void, applied to FE prediction. The mean and standard deviation of the THTL data were 0.95 and 15%, respectively, when comparing the THTL data with the original Saha and Zuber correlation, and 0.93 and 10% when comparing them with the modification. Comparison with the worldwide database showed a mean and standard deviation of 1.37 and 53%, respectively, for the original Saha and Zuber correlation and 1.0 and 27% for the modification.

  16. Depolymerization study of sodium hyaluronate by flow field-flow fractionation/multiangle light scattering.

    PubMed

    Kwon, Ji Hye; Hwang, Euijin; Cho, Il-Hwan; Moon, Myeong Hee

    2009-09-01

    Thermal depolymerization of ultrahigh-molecular-weight (UHMW) sodium hyaluronate (NaHA) was studied systematically by using frit-inlet asymmetrical flow field-flow fractionation/multiangle light scattering/differential refractive index (FI-AFlFFF/MALS/DRI). FI-AFlFFF was utilized for the size separation of NaHA samples which had been thermally degraded for varied treatment times, followed by light-scattering detection to determine MW and structural information of degraded NaHA products. Analysis of NaHA products showed time-dependent depolymerization of raw molecules into smaller-MW components, as well as unfolding of compact structures of UHMW NaHA. To determine whether the observed decrease in MW of sodium hyaluronate originated from the chain degradation of UHMW molecules or from dissociation of entangled complex particles that may have been formed by intermolecular association, narrow size fractions (1 x 10(7)-6 x 10(7) and >6 x 10(7) MW) of NaHA molecules were collected during FlFFF separation and followed by thermal treatment. Subsequent FI-AFlFFF/MALS analysis of collected fractions after thermal treatment suggested that the ultrahigh-MW region (>10(7) Da) of NaHA is likely to result from supermolecular structures formed by aggregation of large molecules. PMID:19649622

  17. New and classical applications of heat flow studies

    NASA Astrophysics Data System (ADS)

    Clauser, C.

    2005-12-01

    This special issue of Journal of Geophysics and Engineering is dedicated to a collection of papers which resulted from an international workshop held in Aachen, Germany, on 4-7 October 2004, called 'New and Classical Applications of Heat Flow Studies'. This was the third in a series of topical geothermal workshops arranged by the Geothermal Working Group of the German Geophysical Society (DGG) and was organized by the Institute of Applied Geophysics at RWTH Aachen University under the auspices of the International Heat Flow Commission of the International Association of Seismology and Physics (IASPEI). The meeting was attended by some 60 scientists from 14 countries and three continents. Financial assistance, granted by DGG and IASPEI, allowed us to provide partial support for a total of eight students, young scientists and eminent researchers from eastern Europe and overseas. The convenors of the meeting were Christoph Clauser (Aachen), Thomas Kohl (Zürich) and Makoto Taniguchi (Kyoto). The main local organizers were Volker Rath (scientific programme) and Ute Kreutz (accommodation and financial affairs). The topics addressed in more than 50 oral and poster presentations indicated that today intriguing new applications of heat flow studies have emerged, complementing the classical topics of heat flow mapping and the tectonic implications of heat flow. In classical applications, for instance, thermal signatures of water flow or downward diffusion of variations in the Earth's mean temperature are considered as noise which needs to be corrected prior to further use of the data. In contrast, in several new applications it is exactly the information contained in these signatures which has been extracted and interpreted. For instance, over the past two decades, work on the most prominent of these new applications has been devoted to inverting the variation of the Earth's past mean ground surface temperature (GST). As of today, GST provided by the geothermal method has

  18. A comparative flow visualization study of thermocapillary flow in drops in liquid-liquid systems

    NASA Technical Reports Server (NTRS)

    Balasubramaniam, R.; Rashidnia, N.

    1991-01-01

    Experiments are performed to visualize thermocapillary flow in drops in an immiscible host liquid. The host liquid used is silicone oil. Drops of three different liquids are used, viz, vegetable oil, water-methanol mixture anad pure methanol. Clear evidence of thermocapillary flow is seen in vegetable oil drops. For a mixture of water and methanol (approximately 50-50 by weight), natural convection is seen to dominate the flow outside the drop. Pure methanol drops exhibit thermocapillary flow, but dissolve in silicone oil. A small amount of water added to pure methanol significantly reduces the dissolution. Flow oscillations occur in this system for both isothermal and non-isothermal conditions.

  19. Study of subcritical flow through multiple-orifice valves

    SciTech Connect

    Surbey, D.W.; Kelkar, B.G.; Brill, J.P.

    1988-02-01

    Increased oil and gas production from offshore areas and hostile environments has led to a greater use of multiple-orifice-valve (MOV) wellhead chokes. Unlike conventional wellhead chokes, MOV's can be adjusted to any given choke area while under pressure, allowing wells in remote locations to be controlled from a central site. Data on the behavior of multiphase flow through MOV chokes have not been available in the past. This study investigated high-pressure (400 to 800 psia (2.8 to 5.5 MPa)), two-phase air/water flow through a 2-in. (5.1-cm) MOV choke. Single-phase air and water data were obtained to determine the valve-sizing coefficient, C/sub v/. A correlating parameter was determined with two-phase data to predict the subcritical two-phase pressure drop. This parameter was found to be a function of the gas/liquid ratio, upstream pressure, and choke opening. A mathematical model based on experimental observations was developed to predict the subcritical pressure drop across the choke for single-phase liquid flow.

  20. Laboratory study of the underground sound generated by debris flows

    NASA Astrophysics Data System (ADS)

    Huang, Ching-Jer; Shieh, Chieng-Lun; Yin, Hsiao-Yuan

    2004-03-01

    This experimental study investigates the underground sound generated by different kinds of rock motions that occur in debris flows. The experiments were divided into two parts. The first part consisted of measuring the main characteristics of the underground sound caused by friction of a rock rubbed against a bed of gravel and of that caused by a free-falling rock hitting a similar bed of gravel. In the second part a hydrophone was installed at the bottom of a laboratory channel to measure the underground sound of debris flows in that channel. The sound signals were analyzed using both the fast Fourier transform and the Gabor transform to represent the signals in both the frequency and time-frequency domains. The measurement results reveal that the frequency of the sound generated by the rock-gravel bed friction is relatively low, being mostly between 20 and 80 Hz. In contrast, the frequency range of the collision sound is relatively higher, between 10 and 500 Hz. Finally, the frequency of the underground sound caused by the debris flows in the flume is in the range of 20-300 Hz.

  1. Numerical study of sink-flow boundary layers

    NASA Technical Reports Server (NTRS)

    Spalart, Philippe R.

    1986-01-01

    Direct numerical simulations of sink-flow boundary layers, with acceleration parameters K between 1.5 x 10 to the -6th and 3.0 x 10 to the -6th, are presented. The three-dimensional, time-dependent Navier-Stokes equations are solved numerically, using a spectral method, with about one million degrees of freedom. The flow is assumed to be statistically steady, and self-similar. A multiple-scale approximation and periodic conditions are applied to the fluctuations. The turbulence is studied using instantaneous and statistical results. Good agreement with the experiments of Jones and Launder (1972) is observed. The two effects of the favorable pressure gradient are to extend the logarithmic layer, and to alter the energy balance of the turbulence near the edge of the boundary layer. At low Reynolds number the logarithmic layer is shortened and slightly displaced, but wall-layer streaks are present even at the lowest values of R(theta) for which turbulence can be sustained. Large quiescent patches appear in the flow. Relaminarization occurs at K = 3.0 x 10 to the -6th, corresponding to a Reynolds number R(theta) of about 330.

  2. Study of argon flowing afterglow with nitrogen injection

    SciTech Connect

    Mazánková, V.; Krčma, F.; Trunec, D.

    2013-10-28

    In this work, the reaction kinetics in argon flowing afterglow with nitrogen addition was studied by optical emission spectroscopy. The DC flowing post-discharge in pure argon was created in quartz tube at the total gas pressure of 1000 Pa and discharge power of 60 W. The nitrogen was added into the afterglow at the distance of 9 cm behind the active discharge. The optical emission spectra were measured along the flow tube. The argon spectral lines and after nitrogen addition also nitrogen second positive system (SPS) were identified in the spectra. The measurement of spatial dependence of SPS intensity showed a very slow decay of the intensity and the decay rate did not depend on the nitrogen concentration. In order to explain this behavior a kinetic model for reaction in afterglow was developed. This model showed that C {sup 3}Π{sub u} state of molecular nitrogen, which is the upper state of SPS emission, is produced by excitation transfer from argon metastables to nitrogen molecules. However, the argon metastables are also produced at Ar{sub 2}{sup +} ion recombination with electrons and this limits the decay of argon metastable concentration and it results in very slow decay of SPS intensity.

  3. 40 CFR 414.60 - Applicability; description of the commodity organic chemicals subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the manufacture of the following SIC 2865 and 2869 commodity organic chemicals and commodity organic... Ethanol Ethylene Ethylene Glycol Ethylene Oxide Formaldehyde Isopropanol Methanol Polyoxypropylene...

  4. 7 CFR 917.20 - Designation of members of commodity committees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE FRESH PEARS... of members of commodity committees. There is hereby established a Pear Commodity Committee...

  5. 7 CFR 917.20 - Designation of members of commodity committees.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS... of members of commodity committees. There is hereby established a Pear Commodity Committee...

  6. 7 CFR 917.20 - Designation of members of commodity committees.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE FRESH PEARS... of members of commodity committees. There is hereby established a Pear Commodity Committee...

  7. Damping parameter study of a perforated plate with bias flow

    NASA Astrophysics Data System (ADS)

    Mazdeh, Alireza

    One of the main impediments to successful operation of combustion systems in industrial and aerospace applications including gas turbines, ramjets, rocket motors, afterburners (augmenters) and even large heaters/boilers is the dynamic instability also known as thermo-acoustic instability. Concerns with this ongoing problem have grown with the introduction of Lean Premixed Combustion (LPC) systems developed to address the environmental concerns associated with the conventional combustion systems. The most common way to mitigate thermo-acoustic instability is adding acoustic damping to the combustor using acoustic liners. Recently damping properties of bias flow initially introduced to liners only for cooling purposes have been recognized and proven to be an asset in enhancing the damping effectiveness of liners. Acoustic liners are currently being designed using empirical design rules followed by build-test-improve steps; basically by trial and error. There is growing concerns on the lack of reliability associated with the experimental evaluation of the acoustic liners with small size apertures. The development of physics-based tools in assisting the design of such liners has become of great interest to practitioners recently. This dissertation focuses primarily on how Large-Eddy Simulations (LES) or similar techniques such as Scaled Adaptive Simulation (SAS) can be used to characterize damping properties of bias flow. The dissertation also reviews assumptions made in the existing analytical, semi-empirical, and numerical models, provides a criteria to rank order the existing models, and identifies the best existing theoretical model. Flow field calculations by LES provide good insight into the mechanisms that led to acoustic damping. Comparison of simulation results with empirical and analytical studies shows that LES simulation is a viable alternative to the empirical and analytical methods and can accurately predict the damping behavior of liners. Currently the

  8. Parametric Studies of Flow Separation using Air Injection

    NASA Technical Reports Server (NTRS)

    Zhang, Wei

    2004-01-01

    Boundary Layer separation causes the airfoil to stall and therefore imposes dramatic performance degradation on the airfoil. In recent years, flow separation control has been one of the active research areas in the field of aerodynamics due to its promising performance improvements on the lifting device. These active flow separation control techniques include steady and unsteady air injection as well as suction on the airfoil surface etc. This paper will be focusing on the steady and unsteady air injection on the airfoil. Although wind tunnel experiments revealed that the performance improvements on the airfoil using injection techniques, the details of how the key variables such as air injection slot geometry and air injection angle etc impact the effectiveness of flow separation control via air injection has not been studied. A parametric study of both steady and unsteady air injection active flow control will be the main objective for this summer. For steady injection, the key variables include the slot geometry, orientation, spacing, air injection velocity as well as the injection angle. For unsteady injection, the injection frequency will also be investigated. Key metrics such as lift coefficient, drag coefficient, total pressure loss and total injection mass will be used to measure the effectiveness of the control technique. A design of experiments using the Box-Behnken Design is set up in order to determine how each of the variables affects each of the key metrics. Design of experiment is used so that the number of experimental runs will be at minimum and still be able to predict which variables are the key contributors to the responses. The experiments will then be conducted in the 1ft by 1ft wind tunnel according to the design of experiment settings. The data obtained from the experiments will be imported into JMP, statistical software, to generate sets of response surface equations which represent the statistical empirical model for each of the metrics as

  9. Parallelisation study of a three-dimensional environmental flow model

    NASA Astrophysics Data System (ADS)

    O'Donncha, Fearghal; Ragnoli, Emanuele; Suits, Frank

    2014-03-01

    There are many simulation codes in the geosciences that are serial and cannot take advantage of the parallel computational resources commonly available today. One model important for our work in coastal ocean current modelling is EFDC, a Fortran 77 code configured for optimal deployment on vector computers. In order to take advantage of our cache-based, blade computing system we restructured EFDC from serial to parallel, thereby allowing us to run existing models more quickly, and to simulate larger and more detailed models that were previously impractical. Since the source code for EFDC is extensive and involves detailed computation, it is important to do such a port in a manner that limits changes to the files, while achieving the desired speedup. We describe a parallelisation strategy involving surgical changes to the source files to minimise error-prone alteration of the underlying computations, while allowing load-balanced domain decomposition for efficient execution on a commodity cluster. The use of conjugate gradient posed particular challenges due to implicit non-local communication posing a hindrance to standard domain partitioning schemes; a number of techniques are discussed to address this in a feasible, computationally efficient manner. The parallel implementation demonstrates good scalability in combination with a novel domain partitioning scheme that specifically handles mixed water/land regions commonly found in coastal simulations. The approach presented here represents a practical methodology to rejuvenate legacy code on a commodity blade cluster with reasonable effort; our solution has direct application to other similar codes in the geosciences.

  10. Evaluation of chlorpyrifos transferred from contaminated feed to duck commodities and dietary risks to Chinese consumers.

    PubMed

    Li, Rui; Ji, Xiaofeng; He, Liang; Liu, Zhiqiang; Wei, Wei; Qiang, Mingrong; Wang, Qiang; Yuan, Yuwei

    2015-06-01

    The present study describes chlorpyrifos residues in duck commodities through the duck food chain, transfer factors, and dietary risks to Chinese consumers. After duck feeding experiments with pellet feed that lasted for 42 days, chlorpyrifos residues found in all samples collected from the ducks on maximum estimated dose group (3.20 mg/kg level) were from <0.0005 to 0.019 mg/kg. The residue levels of the fat, intestine, and tongue were obviously higher than those of the meat and other edible tissues. The transfer factors of all duck commodities were from 0.0001 to 0.0049 among different contamination levels, which indicated that chlorpyrifos had a low persistency in duck meat and metabolism organs. The chronic exposure assessment revealed that only 0.034-0.150% of the acceptable daily intake (ADI; 0-0.01 mg/kg/bw/day) of chlorpyrifos was consumed via the duck commodities for different age and gender groups in China. The acute exposure assessments of different age and gender groups were only 0.019-0.082% of the acute reference dose (ARfD; 0-0.1 mg/kg/bw). The results show that the single dietary exposure risk of chlorpyrifos raised by the intake of duck commodities was quite low in China. PMID:25946472

  11. Revisiting Maxwell’s accommodation coefficient: A study of nitrogen flow in a silica microtube across all flow regimes

    SciTech Connect

    Lei, Wenwen McKenzie, David R.

    2014-12-15

    Gas flows have been studied quantitatively for more than a hundred years and have relevance in modern fields such as the control of gas inputs to processes, the measurement of leak rates and the separation of gaseous species. Cha and McCoy have derived a convenient formula for the flow of an ideal gas applicable across a wide range of Knudsen numbers (Kn) that approaches the Navier–Stokes equations at small Kn and the Smoluchowski extension of the Knudsen flow equation at large Kn. Smoluchowski’s result relies on the Maxwell definition of the tangential momentum accommodation coefficient α, recently challenged by Arya et al. We measure the flow rate of nitrogen gas in a smooth walled silica tube across a wide range of Knudsen numbers from 0.0048 to 12.4583. We find that the nitrogen flow obeys the Cha and McCoy equation with a large value of α, unlike carbon nanotubes which show flows consistent with a small value of α. Silica capillaries are therefore not atomically smooth. The flow at small Kn has α=0.91 and at large Kn has α close to one, consistent with the redefinition of accommodation coefficient by Arya et al., which also resolves a problem in the literature where there are many observations of α of less than one at small Kn and many equal to one at large Kn. Silica capillaries are an excellent choice for an accurate flow control system. - Highlights: • First experimental study on flow rate across all flow regimes in a well-defined microtube. • Extend Cha and McCoy theory for molecular flow regime. • Demonstrate the Maxwell accommodation coefficient is different in the slip and molecular flow regimes.

  12. Studies on pressure losses and flow rate optimization in vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Tang, Ao; Bao, Jie; Skyllas-Kazacos, Maria

    2014-02-01

    Premature voltage cut-off in the operation of the vanadium redox flow battery is largely associated with the rise in concentration overpotential at high state-of-charge (SOC) or state-of-discharge (SOD). The use of high constant volumetric flow rate will reduce concentration overpotential, although potentially at the cost of consuming excessive pumping energy which in turn lowers system efficiency. On the other hand, any improper reduction in flow rate will also limit the operating SOC and lead to deterioration in battery efficiency. Pressure drop losses are further exacerbated by the need to reduce shunt currents in flow battery stacks that requires the use of long, narrow channels and manifolds. In this paper, the concentration overpotential is modelled as a function of flow rate in an effort to determine an appropriate variable flow rate that can yield high system efficiency, along with the analysis of pressure losses and total pumping energy. Simulation results for a 40-cell stack under pre-set voltage cut-off limits have shown that variable flow rates are superior to constant flow rates for the given system design and the use of a flow factor of 7.5 with respect to the theoretical flow rate can reach overall high system efficiencies for different charge-discharge operations.

  13. Experimental and numerical study of patterns in laryngeal flow

    NASA Astrophysics Data System (ADS)

    Chisari, N. E.; Artana, G.; Sciamarella, D.

    2009-05-01

    Unsteady airflow is investigated in a channel with a geometry approximating that of the human larynx. The laryngeal flow is simulated by solving the Navier-Stokes equations for an incompressible two-dimensional viscous fluid, and visualized using the Schlieren technique in an experimental setup consisting of a rigid replica of the larynx, with and without ventricular bands. This study shows the spontaneous formation of vortex couples in several regions of the laryngeal profile, and at different stages of the evolution of the starting glottal jet.

  14. Transverse flow reactor studies of the dynamics of radical reactions

    SciTech Connect

    Macdonald, R.G.

    1993-12-01

    Radical reactions are in important in combustion chemistry; however, little state-specific information is available for these reactions. A new apparatus has been constructed to measure the dynamics of radical reactions. The unique feature of this apparatus is a transverse flow reactor in which an atom or radical of known concentration will be produced by pulsed laser photolysis of an appropriate precursor molecule. The time dependence of individual quantum states or products and/or reactants will be followed by rapid infrared laser absorption spectroscopy. The reaction H + O{sub 2} {yields} OH + O will be studied.

  15. Colloidal Suspensions in Shear Flow : a Real Space Study

    NASA Astrophysics Data System (ADS)

    Derks, D.

    2006-09-01

    We investigate the effect of shear flow on the microstructure of colloidal suspensions by means of microscopy. Systems of nearly equally sized particles are used, whose interactions and phase behavior are predominantly determined by their size and shape, and can further be tuned by the addition of polymers. Recently, a new type of shear cell was developed to study flowing suspensions in real space. The key property of this setup is the counter-rotating principle of the cone and plate, opening up the possibility to create a stationary layer in the bulk of the cell. In Chapter 2, we elaborate on the details of this setup and its performance. Fluorescence confocal microscopy is used to visualize the sheared suspension, and allows imaging of individual particles in the bulk in the stationary plane for a prolonged time. This way, the particle positions in a layer of, for example, a sheared colloidal crystal can be tracked. The particle dynamics in colloidal crystals in shear flow are the subject of Chapter 3. Here, the particles interact through a (nearly) hard sphere potential. Apart from the alignment of the crystal in the shear field and the collective zigzag motion, which had also been deduced from early scattering experiments, we find that random particle displacements increase with shear rate. Those increased fluctuations result in shear induced melting when their mean square displacement has reached about 13 % of the particle separation. Apart from hard spheres, we investigate mixtures of colloids and polymers in shear flow. The polymers cause an effective attraction between the spheres, leading to phase separation into a colloid rich (polymer poor) and a colloid poor (polymer rich) phase at sufficiently high colloid and polymer concentration. In Chapter 4, we study the demixing process in the (spinodal) two-phase region of the phase diagram. The system is quenched from an initially almost homogeneous state at very high shear rate to a low shear rate. A spinodal

  16. Flow around fishlike shapes studied using multiparticle collision dynamics.

    PubMed

    Reid, Daniel A P; Hildenbrandt, H; Padding, J T; Hemelrijk, C K

    2009-04-01

    Empirical measurements of hydrodynamics of swimming fish are very difficult. Therefore, modeling studies may be of great benefit. Here, we investigate the suitability for such a study of a recently developed mesoscale method, namely, multiparticle collision dynamics. As a first step, we confine ourselves to investigations at intermediate Reynolds numbers of objects that are stiff. Due to the lack of empirical data on the hydrodynamics of stiff fishlike shapes we use a previously published numerical simulation of the shapes of a fish and a tadpole for comparison. Because the shape of a tadpole resembles that of a circle with an attached splitter plate, we exploit the knowledge on hydrodynamic consequences of such an attachment to test the model further and study the effects of splitter plates for objects of several shapes at several Reynolds numbers. Further, we measure the angles of separation of flow around a circular cylinder and make small adjustments to the boundary condition and the method to drive the flow. Our results correspond with empirical data and with results from other models. PMID:19518339

  17. Experimental study of mixing enhancement using pylon in supersonic flow

    NASA Astrophysics Data System (ADS)

    Vishwakarma, Manmohan; Vaidyanathan, Aravind

    2016-01-01

    The Supersonic Combustion Ramjet (SCRAMJET) engine has been recognized as one of the most promising air breathing propulsion system for the supersonic/hypersonic flight mission requirements. Mixing and combustion of fuel inside scramjet engine is one of the major challenging tasks. In the current study the main focus has been to increase the penetration and mixing of the secondary jet inside the test chamber at supersonic speeds. In view of this, experiments are conducted to evaluate the effect of pylon on the mixing of secondary jet injection into supersonic mainstream flow at Mach 1.65. Two different pylons are investigated and the results are compared with those obtained by normal injection from a flat plate. The mixing studies are performed by varying the height of the pylon while keeping all other parameters the same. The study mainly focused on analyzing the area of spread and penetration depth achieved by different injection schemes based on the respective parameters. The measurements involved Mie scattering visualization and the flow features are analyzed using Schlieren images. The penetration height and spread area are the two parameters that are used for analyzing and comparing the performance of the pylons. It is observed that the secondary jet injection carried out from behind the big pylon resulted in maximum penetration and spread area of the jet as compared to the small pylon geometry. Moreover it is also evident that for obtaining maximum spreading and penetration of the jet, the same needs to be achieved at the injection location.

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

    NASA Astrophysics Data System (ADS)

    Coppola, Gianfilippo; Gomez, Alessandro

    2010-10-01

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

  19. Development, testing and application of DrainFlow: A fully distributed integrated surface-subsurface flow model for drainage study

    NASA Astrophysics Data System (ADS)

    Shokri, Ali; Bardsley, William Earl

    2016-06-01

    Hydrological and hydrogeological investigation of drained land is a complex and integrated procedure. The scale of drainage studies may vary from a high-resolution small scale project through to comprehensive catchment or regional scale investigations. This wide range of scales and integrated system behaviour poses a significant challenge for the development of suitable drainage models. Toward meeting these requirements, a fully distributed coupled surface-subsurface flow model titled DrainFlow has been developed and is described. DrainFlow includes both the diffusive wave equation for surface flow components (overland flow, open drain, tile drain) and Richard's equation for saturated/unsaturated zones. To overcome the non-linearity problem created from switching between wet and dry boundaries, a smooth transitioning technique is introduced to buffer the model at tile drains and at interfaces between surface and subsurface flow boundaries. This gives a continuous transition between Dirichlet and Neumann boundary conditions. DrainFlow is tested against five well-known integrated surface-subsurface flow benchmarks. DrainFlow as applied to some synthetic drainage study examples is quite flexible for changing all or part of the model dimensions as required by problem complexity, problem scale, and data availability. This flexibility enables DrainFlow to be modified to allow for changes in both scale and boundary conditions, as often encountered in real-world drainage studies. Compared to existing drainage models, DrainFlow has the advantage of estimating actual infiltration directly from the partial differential form of Richard's equation rather than through analytical or empirical infiltration approaches like the Green and Ampt equation.

  20. Comparison of production-phase environmental impact metrics derived at the farm- and national-scale for United States agricultural commodities

    NASA Astrophysics Data System (ADS)

    Costello, Christine; Xue, Xiaobo; Howarth, Robert W.

    2015-11-01

    Agricultural production is critical for human survival and simultaneously contributes to ecosystem degradation. There is a need for transparent, rapid methods for evaluating the environmental impacts of agricultural production at the system-level in order to develop sustainable food supplies. We have developed a method for estimating the greenhouse gas (GHG), land use and reactive nitrogen inputs associated with the agricultural production phase of major crop and livestock commodities produced in the United States (US). Materials flow analysis (MFA) and life cycle assessment (LCA) techniques were applied to national inventory datasets. The net anthropogenic nitrogen inputs (NANI) toolbox served as the primary accounting tool for LCA and MFA. NANI was updated to create links between nitrogen fertilizer and nitrogen fixation associated with feed crops and animal food commodities. Results for the functional units kilogram (kg) of product and kg of protein for 2002 data fall within ranges of published LCA results from farm-scale studies across most metrics. Exceptions include eutrophication potential for milk and GHGs for chicken and eggs, these exceptions arise due to differing methods and boundary assumptions; suggestions for increasing agreement are identified. Land use for livestock commodities are generally higher than reported by other LCA studies due to the inclusion of all land identified as pasture or grazing land in the US in this study and given that most of the estimates from other LCAs were completed in Europe where land is less abundant. The method provides a view of the entire US agricultural system and could be applied to any year using publically available data. Additionally, utilizing a top-down approach reduces data collection and processing time making it possible to develop environmental inventory metrics rapidly for system-level decision-making.

  1. Drainage flows: A mountain-plains interface numerical case study

    SciTech Connect

    Poulos, G.S.; Bossert, J.E.

    1992-01-01

    In January/February, 1991 an intensive set of measurements was taken around Rocky Flats near Denver, CO, USA under the auspices of the Atmospheric Studies in Complex Terrain (ASCOT) program. This region of the country is known as the Front Range, and is characterized by a transition from the relatively flat terrain of the Great Plains to the highly varied terrain of the Rocky Mountains. The mountains are oriented north-south and rise from 1800m above mean sea level (MSL) to 3600m MSL at the Continental Divide. Numerous east-west oriented valleys begin in the mountains and end at the plains interface. This terrain makes the Front Range a challenging region to model. One of the more important flows created by this severe terrain are the highly-varying drainage flows found during stagnant, wintertime conditions. These flows can interact with larger-scale mountain and synoptic winds. One goal of the ASCOT 1991 program was to gain insight into multi-scale meteorological interaction by observing wintertime drainage conditions at the mountain-valley-plains interface. ASCOT data included surface and upper air measurements on approximately a 50km{sup 2} scale. Simultaneously, an SF{sub 6} tracer release study was being conducted around Rocky Flats, a nuclear materials production facility. Detailed surface concentration measurements were completed for the SF{sub 6} plume. This combination of meteorological and tracer concentration data provided a unique data set for comparisons of mesoscale and dispersion modeling results with observations and for evaluating our capability to predict pollutant transport. Our approach is to use the Regional Atmospheric Modeling System (RAMS) mesoscale model to simulate atmospheric conditions and the Lagrangian Particle Dispersion Model (LPDM) to model the dispersion of the SF{sub 6}.

  2. Drainage flows: A mountain-plains interface numerical case study

    SciTech Connect

    Poulos, G.S.; Bossert, J.E.

    1992-09-01

    In January/February, 1991 an intensive set of measurements was taken around Rocky Flats near Denver, CO, USA under the auspices of the Atmospheric Studies in Complex Terrain (ASCOT) program. This region of the country is known as the Front Range, and is characterized by a transition from the relatively flat terrain of the Great Plains to the highly varied terrain of the Rocky Mountains. The mountains are oriented north-south and rise from 1800m above mean sea level (MSL) to 3600m MSL at the Continental Divide. Numerous east-west oriented valleys begin in the mountains and end at the plains interface. This terrain makes the Front Range a challenging region to model. One of the more important flows created by this severe terrain are the highly-varying drainage flows found during stagnant, wintertime conditions. These flows can interact with larger-scale mountain and synoptic winds. One goal of the ASCOT 1991 program was to gain insight into multi-scale meteorological interaction by observing wintertime drainage conditions at the mountain-valley-plains interface. ASCOT data included surface and upper air measurements on approximately a 50km{sup 2} scale. Simultaneously, an SF{sub 6} tracer release study was being conducted around Rocky Flats, a nuclear materials production facility. Detailed surface concentration measurements were completed for the SF{sub 6} plume. This combination of meteorological and tracer concentration data provided a unique data set for comparisons of mesoscale and dispersion modeling results with observations and for evaluating our capability to predict pollutant transport. Our approach is to use the Regional Atmospheric Modeling System (RAMS) mesoscale model to simulate atmospheric conditions and the Lagrangian Particle Dispersion Model (LPDM) to model the dispersion of the SF{sub 6}.

  3. Balancing detail and scale in assessing transparency to improve the governance of agricultural commodity supply chains

    NASA Astrophysics Data System (ADS)

    Godar, Javier; Suavet, Clément; Gardner, Toby A.; Dawkins, Elena; Meyfroidt, Patrick

    2016-03-01

    To date, assessments of the sustainability of agricultural commodity supply chains have largely relied on some combination of macro-scale footprint accounts, detailed life-cycle analyses and fine-scale traceability systems. Yet these approaches are limited in their ability to support the sustainability governance of agricultural supply chains, whether because they are intended for coarser-grained analyses, do not identify individual actors, or are too costly to be implemented in a consistent manner for an entire region of production. Here we illustrate some of the advantages of a complementary middle-ground approach that balances detail and scale of supply chain transparency information by combining consistent country-wide data on commodity production at the sub-national (e.g. municipal) level with per shipment customs data to describe trade flows of a given commodity covering all companies and production regions within that country. This approach can support supply chain governance in two key ways. First, enhanced spatial resolution of the production regions that connect to individual supply chains allows for a more accurate consideration of geographic variability in measures of risk and performance that are associated with different production practices. Second, identification of key actors that operate within a specific supply chain, including producers, traders, shippers and consumers can help discriminate coalitions of actors that have shared stake in a particular region, and that together are capable of delivering more cost-effective and coordinated interventions. We illustrate the potential of this approach with examples from Brazil, Indonesia and Colombia. We discuss how transparency information can deepen understanding of the environmental and social impacts of commodity production systems, how benefits are distributed among actors, and some of the trade-offs involved in efforts to improve supply chain sustainability. We then discuss the challenges and

  4. Computational wing design studies relating to natural laminar flow

    NASA Technical Reports Server (NTRS)

    Waggoner, Edgar G.

    1986-01-01

    Two research studies are described which directly relate to the application of natural laminar flow (NLF) technology to transonic transport-type wing planforms. Each involved using state-of-the-art computational methods to design three-dimensional wing contours which generate significant runs of favorable pressure gradients. The first study supported the Variable Sweep Transition Flight Experiment and involves design of a full-span glove which extends from the leading edge to the spoiler hinge line on the upper surface of an F-14 outer wing panel. A wing was designed computationally for a corporate transport aircraft in the second study. The resulting wing design generated favorable pressure gradients from the leading edge aft to the mid-chord on both upper and lower surfaces at the cruise design point. Detailed descriptions of the computational design approach are presented along with the various constraints imposed on each of the designs.

  5. A visual study of radial inward choked flow of liquid nitrogen

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Simoneau, R. J.; Hsu, Y. Y.

    1973-01-01

    A visual study of the radial inward choked flow of liquid nitrogen was conducted. Data and high speed moving pictures were obtained. The study indicated the following: (1) steady radial inward choked flow seems equivalent to steady choked flow through axisymmetric nozzles, (2) transient choked flows through the radial gap are not uniform and the discharge pattern appears as nonuniform impinging jets, and (3) the critical mass flow rate data for the transient case appear different from those of the steady case.

  6. Comparative study of heat transfer and pressure drop during flow boiling and flow condensation in minichannels

    NASA Astrophysics Data System (ADS)

    Mikielewicz, Dariusz; Andrzejczyk, Rafał; Jakubowska, Blanka; Mikielewicz, Jarosław

    2014-09-01

    In the paper a method developed earlier by authors is applied to calculations of pressure drop and heat transfer coefficient for flow boiling and also flow condensation for some recent data collected from literature for such fluids as R404a, R600a, R290, R32,R134a, R1234yf and other. The modification of interface shear stresses between flow boiling and flow condensation in annular flow structure are considered through incorporation of the so called blowing parameter. The shear stress between vapor phase and liquid phase is generally a function of nonisothermal effects. The mechanism of modification of shear stresses at the vapor-liquid interface has been presented in detail. In case of annular flow it contributes to thickening and thinning of the liquid film, which corresponds to condensation and boiling respectively. There is also a different influence of heat flux on the modification of shear stress in the bubbly flow structure, where it affects bubble nucleation. In that case the effect of applied heat flux is considered. As a result a modified form of the two-phase flow multiplier is obtained, in which the nonadiabatic effect is clearly pronounced.

  7. NMR and protein folding: equilibrium and stopped-flow studies.

    PubMed Central

    Frieden, C.; Hoeltzli, S. D.; Ropson, I. J.

    1993-01-01

    NMR studies are now unraveling the structure of intermediates of protein folding using hydrogen-deuterium exchange methodologies. These studies provide information about the time dependence of formation of secondary structure. They require the ability to assign specific resonances in the NMR spectra to specific amide protons of a protein followed by experiments involving competition between folding and exchange reactions. Another approach is to use 19F-substituted amino acids to follow changes in side-chain environment upon folding. Current techniques of molecular biology allow assignments of 19F resonances to specific amino acids by site-directed mutagenesis. It is possible to follow changes and to analyze results from 19F spectra in real time using a stopped-flow device incorporated into the NMR spectrometer. PMID:8298453

  8. Entrainment of granular substrate by pyroclastic flows: an experimental study and its implications for flow dynamics

    NASA Astrophysics Data System (ADS)

    Roche, O.; Niño, Y.; Mangeney, A.; Brand, B. D.; Valentine, G. A.

    2012-12-01

    Pyroclastic flows deposits may contain lithics entrained from an unconsolidated granular substrate on which the flows emplaced. In order to address this issue, analog experiments on dense gas-particle flows propagating on a horizontal granular layer were carried out to elucidate the entrainment mechanisms and to infer the dynamics of pyroclastic flows. The experimental flows were generated from the release of gas-fluidized columns of fine (80 μm) particles in a horizontal channel whose base was made of an unconsolidated granular layer. The flows consisted of a fluidized air-particles mixture, and the small hydraulic permeability of the material allowed for long-lived high interstitial pore fluid pressure during emplacement. Basal pore pressure measurements in preliminary experiments involving a rigid substrate revealed that the sliding head of the flows generated a dynamic underpressure (relative to atmosphere) proportional to the square of the front velocity. As such underpressure at the flow base was likely to promote an upward pressure gradient that could cause uplift of particles of a granular substrate, we did a theoretical analysis in order to determine the critical underpressure and the corresponding flow velocity (Uc) at which uplift could occur. This analysis showed that Uc~(dρpg/Cρ)1/2 for spherical particles, where d and ρp are the particle diameter and density, respectively, C is an empirical constant, and is ρ is the bulk flow density. It was validated with experiments on flows propagating on 3 cm-thick substrates of steel beads of diameter d=1.6 mm. The beads were first dragged horizontally individually due to basal shear, and onset of uplift did occur at Uc~0.9 m/s. The beads uplifted were incorporated within the flow base, to a height that increased up to 6-8 mm at flow velocities up to 2.5-3 m/s, and were entrained over distances of several tens of cm representing a significant part of the flow runout. The flow deposits hence had a well

  9. Modeling study of terminal transients of blood flow

    NASA Astrophysics Data System (ADS)

    Stiukhina, Elena S.; Postnov, Dmitry E.

    2016-04-01

    In spite of growing body of experimental and theoretical results on blood flow (BF) patterns under the continuously sustained circulation, much less is known about BF dynamics under the exceptional, but still important cases of venous or arterial occlusion used in medical probes. Since these conditions finally lead to complete or nearly complete stop of red blood cells (RBC) motion, we term it as TTBF, being the Terminal Transients of Blood Flow. An extreme case of such transients is the ultimate extinction of BF after the stopping of heart contractions, during which it is governed by gravitation, some vascular-originated propulsion mechanisms, and, possibly, by RBC aggregation. Quite little is known about this process, while reports the detectable post-mortal motion of mice RBC during at least 2 hours. In our work we present the modeling study of TTBF patterns due to gravitational forces. We present the minimalistic model configuration of vasculature in order to simulate what happens immediately after the pumping of blood has been stopped. Our main findings are concerned to reversal of arterial BF, as well as to duration and non-monotonicity of transients.

  10. Study of Spray Disintegration in Accelerating Flow Fields

    NASA Technical Reports Server (NTRS)

    Nurick, W. H.

    1972-01-01

    An analytical and experimental investigation was conducted to perform "proof of principlem experiments to establish the effects of propellant combustion gas velocity on propella'nt atomization characteristics. The propellants were gaseous oxygen (GOX) and Shell Wax 270. The fuel was thus the same fluid used in earlier primary cold-flow atomization studies using the frozen wax method. Experiments were conducted over a range in L* (30 to 160 inches) at two contraction ratios (2 and 6). Characteristic exhaust velocity (c*) efficiencies varied from SO to 90 percent. The hot fire experimental performance characteristics at a contraction ratio of 6.0 in conjunction with analytical predictions from the drovlet heat-up version of the Distributed Energy Release (DER) combustion computer proDam showed that the apparent initial dropsize compared well with cold-flow predictions (if adjusted for the gas velocity effects). The results also compared very well with the trend in perfomnce as predicted with the model. significant propellant wall impingement at the contraction ratio of 2.0 precluded complete evaluation of the effect of gross changes in combustion gas velocity on spray dropsize.

  11. Automatic differentiation for PDES: Unsaturated flow case study

    SciTech Connect

    Corliss, G.F.; Bischof, C.; Griewank, A.; Wright, S.J.; Robey, T.

    1992-07-01

    The techniques of automatic differentiation are applied to an example partial differential equation arising from the modeling of unsaturated flow. One common paradigm for the numerical solution to some classes of two-, three-, or higher-dimensional partial differential equations is as follows: Given a PDE and boundary conditions, apply finite difference or finite element approximations on some appropriate (frequently nonuniform) grid, and enforce an approximate solution by solving a nonlinear system F(u)=0 for the residual by Newton`s method. The dimension of the nonlinear system F(u)=0 is proportional to the number of grid points. In current algorithms, the Jacobian J required by Newton`s method is computed by some combination of hand coding, divided differences, matrix coloring, and partial separability. We present a case study documenting the steps we took in analyzing a code provided by Robey for modeling unsaturated flow in porous media. Our purpose was to compute J by automatic differentiation using ADOL-C, a tool for automatic differentiation using overloaded operators in C++.

  12. Automatic differentiation for PDES: Unsaturated flow case study

    SciTech Connect

    Corliss, G.F.; Bischof, C.; Griewank, A.; Wright, S.J. ); Robey, T. )

    1992-01-01

    The techniques of automatic differentiation are applied to an example partial differential equation arising from the modeling of unsaturated flow. One common paradigm for the numerical solution to some classes of two-, three-, or higher-dimensional partial differential equations is as follows: Given a PDE and boundary conditions, apply finite difference or finite element approximations on some appropriate (frequently nonuniform) grid, and enforce an approximate solution by solving a nonlinear system F(u)=0 for the residual by Newton's method. The dimension of the nonlinear system F(u)=0 is proportional to the number of grid points. In current algorithms, the Jacobian J required by Newton's method is computed by some combination of hand coding, divided differences, matrix coloring, and partial separability. We present a case study documenting the steps we took in analyzing a code provided by Robey for modeling unsaturated flow in porous media. Our purpose was to compute J by automatic differentiation using ADOL-C, a tool for automatic differentiation using overloaded operators in C++.

  13. Studying enzymatic bioreactions in a millisecond microfluidic flow mixer

    PubMed Central

    Buchegger, Wolfgang; Haller, Anna; van den Driesche, Sander; Kraft, Martin; Lendl, Bernhard; Vellekoop, Michael

    2012-01-01

    In this study, the pre-steady state development of enzymatic bioreactions using a microfluidic mixer is presented. To follow such reactions fast mixing of reagents (enzyme and substrate) is crucial. By using a highly efficient passive micromixer based on multilaminar flow, mixing times in the low millisecond range are reached. Four lamination layers in a shallow channel reduce the diffusion lengths to a few micrometers only, enabling very fast mixing. This was proven by confocal fluorescence measurements in the channel’s cross sectional area. Adjusting the overall flow rate in the 200 μm wide and 900 μm long mixing and observation channel makes it possible to investigate enzyme reactions over several seconds. Further, the device enables changing the enzyme/substrate ratio from 1:1 up to 3:1, while still providing high mixing efficiency, as shown for the enzymatic hydrolysis using β-galactosidase. This way, the early kinetics of the enzyme reaction at multiple enzyme/substrate concentrations can be collected in a very short time (minutes). The fast and easy handling of the mixing device makes it a very powerful and convenient instrument for millisecond temporal analysis of bioreactions. PMID:22662071

  14. An experimental study of separated flow on a finite wing

    NASA Technical Reports Server (NTRS)

    Winkelmann, A. E.

    1981-01-01

    The flow field associated with the formation of a mushroom shaped trailing edge stall cell on a low-aspect-ratio (AR = 4.0) wing was investigated in a series of low speed wind tunnel tests (Reynolds number based on 15.2 cm chord = 480,000). Flow field surveys of the separation bubble and wake of a partially stalled and fully stalled wing were completed using a hot-wire probe, a split-film probe, and a directional sensitive pressure probe. A new color video display technique was developed to display the flow field survey data. Photographs were obtained of surface oil flow patterns and smoke flow visualization

  15. 17 CFR 33.4 - Designation as a contract market for the trading of commodity options.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Register citations affecting § 33.4, see the List of CFR Sections Affected, which appears in the Finding... market for the trading of commodity options. 33.4 Section 33.4 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGULATION OF DOMESTIC EXCHANGE-TRADED COMMODITY OPTION...

  16. 7 CFR 1599.9 - Damage to or loss of commodities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Damage to or loss of commodities. 1599.9 Section 1599... Damage to or loss of commodities. (a) FAS will be responsible for the donated commodities prior to the... time period set forth in the agreement, of any damage to or loss of the donated commodities that...

  17. 7 CFR 1599.9 - Damage to or loss of commodities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Damage to or loss of commodities. 1599.9 Section 1599... Damage to or loss of commodities. (a) FAS will be responsible for the donated commodities prior to the... time period set forth in the agreement, of any damage to or loss of the donated commodities that...

  18. 7 CFR 1599.9 - Damage to or loss of commodities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Damage to or loss of commodities. 1599.9 Section 1599... Damage to or loss of commodities. (a) FAS will be responsible for the donated commodities prior to the... time period set forth in the agreement, of any damage to or loss of the donated commodities that...

  19. 7 CFR 1599.9 - Damage to or loss of commodities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Damage to or loss of commodities. 1599.9 Section 1599... Damage to or loss of commodities. (a) FAS will be responsible for the donated commodities prior to the... time period set forth in the agreement, of any damage to or loss of the donated commodities that...

  20. 7 CFR 1499.9 - Damage to or loss of commodities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Damage to or loss of commodities. 1499.9 Section 1499... or loss of commodities. (a) FAS will be responsible for the donated commodities prior to the transfer... forth in the agreement, of any damage to or loss of the donated commodities that occurs following...

  1. 7 CFR 1499.9 - Damage to or loss of commodities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Damage to or loss of commodities. 1499.9 Section 1499... or loss of commodities. (a) FAS will be responsible for the donated commodities prior to the transfer... forth in the agreement, of any damage to or loss of the donated commodities that occurs following...

  2. 17 CFR Appendix A to Part 31 - Schedule of Fees for Registration of Leverage Commodities

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Schedule of Fees for Registration of Leverage Commodities A Appendix A to Part 31 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION LEVERAGE TRANSACTIONS Pt. 31, App. A Appendix A to Part 31—Schedule of Fees...

  3. 22 CFR 201.68 - Maximum prices for commodity-related services.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Maximum prices for commodity-related services... APPLICABLE TO COMMODITY TRANSACTIONS FINANCED BY USAID Price Provisions § 201.68 Maximum prices for commodity-related services. (a) The price for an USAID-financed commodity-related service, other than ocean or...

  4. 44 CFR 402.3 - Addition of commodities to the Positive List.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Addition of commodities to... commodities to the Positive List. Order T-1 applies to the transportation or discharge of commodities which are restricted at the time of transportation or discharge. Accordingly, if a commodity is added to...

  5. 17 CFR 32.12 - Exemption from suspension of commodity option transactions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) By commodity, call or put, and expiration month: (A) The total quantity of the underlying commodity... month. (ii) By commodity and call or put; (A) The total quantity of the underlying commodity on which... business day of the month. (C) The bid and ask option premiums available to option customers through...

  6. 17 CFR 4.27 - Additional reporting by advisors of certain large commodity pools.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... section 4.10(f); (4) Net asset value or NAV has the same meaning as net asset value as defined in section... advisors of certain large commodity pools. 4.27 Section 4.27 Commodity and Securities Exchanges COMMODITY... Operators § 4.27 Additional reporting by advisors of certain large commodity pools. (a) General...

  7. 17 CFR 4.27 - Additional reporting by advisors of certain large commodity pools.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... section 4.10(f); (4) Net asset value or NAV has the same meaning as net asset value as defined in section... advisors of certain large commodity pools. 4.27 Section 4.27 Commodity and Securities Exchanges COMMODITY... Operators § 4.27 Additional reporting by advisors of certain large commodity pools. (a) General...

  8. Standardization as a Means for Globalizing a Commodity: The Case of Rapeseed in China

    ERIC Educational Resources Information Center

    Tanaka, Keiko; Busch, Lawrence

    2003-01-01

    Not all commodities are things, nor are all things available in society commodities. Then, what are commodities? Using the case of rapeseed and its products in China, this paper examines the role of grades and standards (G&S) in simultaneously determining the life of things as commodities and the position of humans as market participants. In the…

  9. Revisiting Maxwell's accommodation coefficient: A study of nitrogen flow in a silica microtube across all flow regimes

    NASA Astrophysics Data System (ADS)

    Lei, Wenwen; McKenzie, David R.

    2014-12-01

    Gas flows have been studied quantitatively for more than a hundred years and have relevance in modern fields such as the control of gas inputs to processes, the measurement of leak rates and the separation of gaseous species. Cha and McCoy have derived a convenient formula for the flow of an ideal gas applicable across a wide range of Knudsen numbers (Kn) that approaches the Navier-Stokes equations at small Kn and the Smoluchowski extension of the Knudsen flow equation at large Kn. Smoluchowski's result relies on the Maxwell definition of the tangential momentum accommodation coefficient α, recently challenged by Arya et al. We measure the flow rate of nitrogen gas in a smooth walled silica tube across a wide range of Knudsen numbers from 0.0048 to 12.4583. We find that the nitrogen flow obeys the Cha and McCoy equation with a large value of α, unlike carbon nanotubes which show flows consistent with a small value of α. Silica capillaries are therefore not atomically smooth. The flow at small Kn has α = 0.91 and at large Kn has α close to one, consistent with the redefinition of accommodation coefficient by Arya et al., which also resolves a problem in the literature where there are many observations of α of less than one at small Kn and many equal to one at large Kn. Silica capillaries are an excellent choice for an accurate flow control system.

  10. A study of Hot Flow Anomalies and their internal structure

    NASA Astrophysics Data System (ADS)

    Shestakov, Artyom; Vaisberg, Oleg

    Hot Flow Anomalies (HFAs) were studied for long time. Here we attempt to study internal structure of HFAs. Our study is based on the Interball Tail Probe data. We used data from ion-spectrometer SCA-1, magnetic field measurements from MIF and ELECTRON spectrometer measurements. We have chosen five anomalies for our investigation on the basis of well resolved structure. We calculated displacement velocity along bow shock, flow velocities within HFA and compared convection patterns within them. We checked the main criteria of HFA formation: motional electric field direction was directed toward current sheet at least at one side of it (except one case), bow shock was quasi-perpendicular at least at one side of HFA, and angle between current sheet normal and solar wind velocity was large. Convection velocities of plasma within HFA were calculated by subtracting average velocity from measured ion velocities along spacecraft trajectory through anomaly. These convection velocities, viewed in coordinate system determined by shock normal and calculated IMF current sheet normal, clearly show separation of HFA region in 3 parts: leading part, narrow central part, and trailing part. HFAs we analyzed can be separated in two groups according to pattern of convection velocities. First type of HFAs have velocities directed from central region and circulation in leading and trailing parts. Second type of HFAs show predominant motion along the current sheet. There also other differences between these two types of HFA that are discussed in presentation. Judging from plasma convection pattern within HFAs received additional evidence that central region is the source of energy and momentum near interplanetary current sheet crossing location. We calculated balance of energy within HFA using momentum equation to estimate what amount of reflected particles is needed for central region to be the energy source.

  11. Modelling volatility recurrence intervals in the Chinese commodity futures market

    NASA Astrophysics Data System (ADS)

    Zhou, Weijie; Wang, Zhengxin; Guo, Haiming

    2016-09-01

    The law of extreme event occurrence attracts much research. The volatility recurrence intervals of Chinese commodity futures market prices are studied: the results show that the probability distributions of the scaled volatility recurrence intervals have a uniform scaling curve for different thresholds q. So we can deduce the probability distribution of extreme events from normal events. The tail of a scaling curve can be well fitted by a Weibull form, which is significance-tested by KS measures. Both short-term and long-term memories are present in the recurrence intervals with different thresholds q, which denotes that the recurrence intervals can be predicted. In addition, similar to volatility, volatility recurrence intervals also have clustering features. Through Monte Carlo simulation, we artificially synthesise ARMA, GARCH-class sequences similar to the original data, and find out the reason behind the clustering. The larger the parameter d of the FIGARCH model, the stronger the clustering effect is. Finally, we use the Fractionally Integrated Autoregressive Conditional Duration model (FIACD) to analyse the recurrence interval characteristics. The results indicated that the FIACD model may provide a method to analyse volatility recurrence intervals.

  12. Quantifying Domestic Used Electronics Flows using a Combination of Material Flow Methodologies: A US Case Study.

    PubMed

    Miller, T Reed; Duan, Huabo; Gregory, Jeremy; Kahhat, Ramzy; Kirchain, Randolph

    2016-06-01

    This paper describes the scope, methods, data, and results of a comprehensive quantitative analysis of generation, stock, and collection of used computers and monitors in the United States , specifically desktops, laptops, CRT monitors, and flat panel monitors in the decade leading up to 2010. Generation refers to used electronics coming directly out of use or postuse storage destined for disposal or collection, which encompasses a variety of organizations gathering used electronics for recycling or reuse. Given the lack of actual statistics on flows of used electronics, two separate approaches, the sales obsolescence method (SOM) and the survey scale-up method (SSUM), were used in order to compare the results attained and provide a range for estimated quantities. This study intentionally sought to capture the uncertainty in the estimates. To do so, uncertainty in each data set was incorporated at each stage using Monte Carlo simulations for SOM and establishing scenarios for SSUM. Considering the average results across both methods, we estimate that in 2010 the U.S. generated 130-164 thousand metric tons of used computers and 128-153 thousand tons of used monitors, of which 110-116 thousand tons of used computers and 105-106 thousand tons of used monitors were collected for further reuse, recycling, or export. While each approach has its strengths and weaknesses, both the SOM and the SSUM appear to be capable of producing reasonable ranges of estimates for the generation and collection of used electronics. PMID:27134153

  13. Numerical study of librationally driven Flow in planetary interiors

    NASA Astrophysics Data System (ADS)

    Laguerre, Raphael; Karatekin, Ozgur; Noir, Jérôme

    2010-05-01

    Forced librations are observed for many planetary bodies. In the case of interior fluid layers, i.e. liquid cores or subsurface oceans, the resulting librational response could be different compared to that of a solid body. The coupling between the fluid layer and mantle depends strongly on the interior properties of the planet. Here we study numerically the properties of a librationally driven flow by taking into account both longitudinal and latitudinal forcing. The numerical method is based on an finite element approximation in meridian planes and a Fourier decomposition of the variables in the azimuthal direction (SFEMANS, Spectral Finite Element for Maxwell and Navier Stokes ). This allows us to specify the direction of rotation vector arbitrarily. In the case of longitudinal forcing we compare our solutions to the experimental results of Noir et al. 2009 obtained for cores with spherical shape. For latitudinal librations, we consider also the influence of ellipticity.

  14. An analytical and numerical study of axisymmetric flow around spheroids

    NASA Astrophysics Data System (ADS)

    Chang, Chien-Cheng; Liou, Biing-Horng; Chern, Ruey-Ling

    1992-01-01

    Axisymmetric viscous flow around ellipsoids of circular section is examined in detail using a matched asymptotic analysis and a deterministic hybrid vortex method. The hybrid vortex method solves the viscous vorticity equation by combining a finite-difference method for diffusion and a vortex-in-cell method for convection and stretching. The numerical study was carried out for an ellipsoid of axis ratio 2:1 and the limiting case of a sphere at Reynolds numbers between 100 and 3000. Particular attention is given to evaluation of the drag coefficient using three different approaches. Numerical and asymptotic results at small times are found to be in good agreement. Separation angles, wake lengths, and stationary drag coefficients for the sphere are also in good agreement with previous results obtained by a finite-difference method and with the standard drag curve.

  15. Experimental Studies of Low-Pressure Turbine Flows and Flow Control. Streamwise Pressure Profiles and Velocity Profiles

    NASA Technical Reports Server (NTRS)

    Volino, Ralph

    2012-01-01

    This report summarizes research performed in support of the NASA Glenn Research Center (GRC) Low-Pressure Turbine (LPT) Flow Physics Program. The work was performed experimentally at the U.S. Naval Academy faculties. The geometry corresponded to "Pak B" LPT airfoil. The test section simulated LPT flow in a passage. Three experimental studies were performed: (a) Boundary layer measurements for ten baseline cases under high and low freestream turbulence conditions at five Reynolds numbers of 25,000, 50,000, 100,000, 200,000, and 300,000, based on passage exit velocity and suction surface wetted length; (b) Passive flow control studies with three thicknesses of two-dimensional bars, and two heights of three-dimensional circular cylinders with different spanwise separations, at same flow conditions as the 10 baseline cases; (c) Active flow control with oscillating synthetic (zero net mass flow) vortex generator jets, for one case with low freestream turbulence and a low Reynolds number of 25,000. The Passive flow control was successful at controlling the separation problem at low Reynolds numbers, with varying degrees of success from case to case and varying levels of impact at higher Reynolds numbers. The active flow control successfully eliminated the large separation problem for the low Reynolds number case. Very detailed data was acquired using hot-wire anemometry, including single and two velocity components, integral boundary layer quantities, turbulence statistics and spectra, turbulent shear stresses and their spectra, and intermittency, documenting transition, separation and reattachment. Models were constructed to correlate the results. The report includes a summary of the work performed and reprints of the publications describing the various studies.This report summarizes research performed in support of the NASA Glenn Research Center (GRC) Low-Pressure Turbine (LPT) Flow Physics Program. The work was performed experimentally at the U.S. Naval Academy

  16. Building and managing high performance, scalable, commodity mass storage systems

    NASA Technical Reports Server (NTRS)

    Lekashman, John

    1998-01-01

    The NAS Systems Division has recently embarked on a significant new way of handling the mass storage problem. One of the basic goals of this new development are to build systems at very large capacity and high performance, yet have the advantages of commodity products. The central design philosophy is to build storage systems the way the Internet was built. Competitive, survivable, expandable, and wide open. The thrust of this paper is to describe the motivation for this effort, what we mean by commodity mass storage, what the implications are for a facility that performs such an action, and where we think it will lead.

  17. A Crosswalk of Mineral Commodity End Uses and North American Industry Classification System (NAICS) codes

    USGS Publications Warehouse

    Barry, James J.; Matos, Grecia R.; Menzie, W. David

    2015-01-01

    The links between the end uses of mineral commodities and the NAICS codes provide an instrument for analyzing the use of mineral commodities in the economy. The crosswalk is also a guide, highlighting those industrial sectors in the economy that rely heavily on mineral commodities. The distribution of mineral commodities across the economy is dynamic and does differ from year to year. This report reflects a snapshot of the state of the economy and mineral commodities in 2010.

  18. Flow channeling in strongly heterogeneous porous media: A numerical study

    SciTech Connect

    Moreno, L.; Tsang, C.F.

    1994-05-01

    The variation of hydraulic conductivity in a porous medium causes the fluids flowing through it to have nonuniform velocities. Variation in fluid velocity is one of the main contributors to solute dispersion, causing a part of the contaminants dissolved in the fluid to be transported with greater than average velocities. In practical problems concerning transport of radioactive or toxic wastes, the velocity of contaminant flow may be of vital importance. This paper examines a three dimensional case, considering also the similarities and differences between parallel flow and convergent/divergent flow. Fluid flow in a porous medium is shown to perfer the most conductive paths. For a medium with strongly variable permeability this effect can be very pronounced. This paper discusses the impact of this flow distribution upon solute transport. 28 refs., 11 figs., 2 tabs.

  19. Flow Visualization Study of a 1/48-Scale AFTI/F111 Model to Investigate Horizontal Tail Flow Disturbances

    NASA Technical Reports Server (NTRS)

    Bjarke, Lisa J.

    1991-01-01

    During flight testing of the AFTI/F111 aircraft, horizontal tail buffet was observed. Flutter analysis ruled out any aeroelastic instability, so a water-tunnel flow visualization study was conducted to investigate possible flow disturbances on the horizontal tail which might cause buffet. For this study, a 1/48-scale model was used. Four different wing cambers and one horizontal tail setting were tested between 0 and 20 deg angle of attack. These wing cambers corresponded to the following leading training edge deflections: 0/2, 10/10, 10/2, and 0/10. Flow visualization results in the form of still photographs are presented for each of the four wing cambers between 8 and 12 deg angle of attack. In general, the horizontal tail experiences flow disturbances which become more pronounced with angle of attack or wing trailing-edge deflection.

  20. Natural laminar flow airfoil analysis and trade studies

    NASA Technical Reports Server (NTRS)

    1979-01-01

    An analysis of an airfoil for a large commercial transport cruising at Mach 0.8 and the use of advanced computer techniques to perform the analysis are described. Incorporation of the airfoil into a natural laminar flow transport configuration is addressed and a comparison of fuel requirements and operating costs between the natural laminar flow transport and an equivalent turbulent flow transport is addressed.

  1. Laboratory Studies of Coherent Structures in Quasi - Flows

    NASA Astrophysics Data System (ADS)

    Meyers, Steven David

    1990-01-01

    Laboratory experiments were conducted in a large, rapidly rotating annulus of fluid. Low Rossby and Ekman numbers, 0.1 and 10^{-5} respectively, were achieved while maintaining large Reynolds number (greater than 10^4). The apparatus had a flat lid and conical bottom (slope s = -0.1) to mimic the planetary beta-effect. Motion was forced with six source-sink pairs, distributed symmetrically in a ring in the bottom of the tank. Two primary flow states were studied: marginally stable westward and eastward jets. Westward jets tended to be wide, and developed a central region of strong shear with quasi-uniform potential vorticity. Elliptical vortices of the same sign as the shear always formed. Due to design limitations, only cyclonic vortices were produced. Multiple vortex states were found for relatively narrow jets when the inertial time scale was comparable to the Ekman time scale. At increasingly shorter inertial time scale, produced with stronger forcing, the number of vortices decreased from a maximum of 5 to 1. The multiple vortex states were essentially laminar, inspite of their high Reynolds number; the single vortex state was turbulent, producing many small vortices that merged with the main vortex. The broad region of quasi -uniform potential vorticity was considered necessary for the formation of a single robust vortex. These vortices had many properties in common with vortices found on the large gaseous planets. Eastward jets tended to be narrow and exhibited Rossby wave instability. The number of waves was fairly well predicted by linear theory, except for the low forcing situation, when the pumping geometry strongly influenced the instability. Potential vorticity was quasi-uniform on either side of the jet, with a strong gradient in the jet center. This gradient was a strong barrier to particle transport. A Hamiltonian model of the flow demonstrated the presence of a robust invariant surface at the jet center, with large chaotic seas on either side. The

  2. Study of nitrogen flowing afterglow with mercury vapor injection

    SciTech Connect

    Mazánková, V. Krčma, F.; Trunec, D.

    2014-10-21

    The reaction kinetics in nitrogen flowing afterglow with mercury vapor addition was studied by optical emission spectroscopy. The DC flowing post-discharge in pure nitrogen was created in a quartz tube at the total gas pressure of 1000 Pa and discharge power of 130 W. The mercury vapors were added into the afterglow at the distance of 30 cm behind the active discharge. The optical emission spectra were measured along the flow tube. Three nitrogen spectral systems – the first positive, the second positive, and the first negative, and after the mercury vapor addition also the mercury resonance line at 254 nm in the spectrum of the second order were identified. The measurement of the spatial dependence of mercury line intensity showed very slow decay of its intensity and the decay rate did not depend on the mercury concentration. In order to explain this behavior, a kinetic model for the reaction in afterglow was developed. This model showed that the state Hg(6 {sup 3}P{sub 1}), which is the upper state of mercury UV resonance line at 254 nm, is produced by the excitation transfer from nitrogen N{sub 2}(A{sup 3}Σ{sup +}{sub u}) metastables to mercury atoms. However, the N{sub 2}(A{sup 3}Σ{sup +}{sub u}) metastables are also produced by the reactions following the N atom recombination, and this limits the decay of N{sub 2}(A{sup 3}Σ{sup +}{sub u}) metastable concentration and results in very slow decay of mercury resonance line intensity. It was found that N atoms are the most important particles in this late nitrogen afterglow, their volume recombination starts a chain of reactions which produce excited states of molecular nitrogen. In order to explain the decrease of N atom concentration, it was also necessary to include the surface recombination of N atoms to the model. The surface recombination was considered as a first order reaction and wall recombination probability γ = (1.35 ± 0.04) × 10{sup −6} was determined from the experimental data. Also

  3. Study of nitrogen flowing afterglow with mercury vapor injection

    NASA Astrophysics Data System (ADS)

    Mazánková, V.; Trunec, D.; Krčma, F.

    2014-10-01

    The reaction kinetics in nitrogen flowing afterglow with mercury vapor addition was studied by optical emission spectroscopy. The DC flowing post-discharge in pure nitrogen was created in a quartz tube at the total gas pressure of 1000 Pa and discharge power of 130 W. The mercury vapors were added into the afterglow at the distance of 30 cm behind the active discharge. The optical emission spectra were measured along the flow tube. Three nitrogen spectral systems - the first positive, the second positive, and the first negative, and after the mercury vapor addition also the mercury resonance line at 254 nm in the spectrum of the second order were identified. The measurement of the spatial dependence of mercury line intensity showed very slow decay of its intensity and the decay rate did not depend on the mercury concentration. In order to explain this behavior, a kinetic model for the reaction in afterglow was developed. This model showed that the state Hg(6 3P1), which is the upper state of mercury UV resonance line at 254 nm, is produced by the excitation transfer from nitrogen N2(A ^3 Σ ^+_u) metastables to mercury atoms. However, the N2(A ^3 Σ ^+_u) metastables are also produced by the reactions following the N atom recombination, and this limits the decay of N2(A ^3 Σ ^+_u) metastable concentration and results in very slow decay of mercury resonance line intensity. It was found that N atoms are the most important particles in this late nitrogen afterglow, their volume recombination starts a chain of reactions which produce excited states of molecular nitrogen. In order to explain the decrease of N atom concentration, it was also necessary to include the surface recombination of N atoms to the model. The surface recombination was considered as a first order reaction and wall recombination probability γ = (1.35 ± 0.04) × 10-6 was determined from the experimental data. Also sensitivity analysis was applied for the analysis of kinetic model in order to

  4. Stability of rotating stratified shear flow: an analytical study.

    PubMed

    Salhi, A; Cambon, C

    2010-02-01

    We study the stability problem of unbounded shear flow, with velocity U(i)=Sx(3)delta(i1), subjected to a uniform vertical density stratification, with Brunt-Väisälä frequency N, and system rotation of rate Omega about an axis aligned with the spanwise (x(2)) direction. The evolution of plane-wave disturbances in this shear flow is governed by a nonhomogeneous second-order differential equation with time-dependent coefficients. An analytical solution is found to be described by Legendre functions in terms of the nondimensional parameter sigma(phi)(2)=R(R+1)sin(2) phi+R(i), where R=(2Omega/S) is the rotation number, phi is the angle between the horizontal wave vector and the streamwise axis, and R(i)=N(2)/S(2) is the Richardson number. The long-time behavior of the solution is analyzed using the asymptotic representations of the Legendre functions. On the one hand, linear stability is analyzed in terms of exponential growth, as in a normal-mode analysis: the rotating stratified shear flow is stable if R(i)>1/4, or if 00, or if R(R+1)<0

  5. Studies of compressible shear flows and turbulent drag reduction

    NASA Technical Reports Server (NTRS)

    Orszag, S. A.

    1981-01-01

    Compressible shear flows and drag reduction were examined and three methods are addressed: (1) the analytical and numerical aspects of conformal mapping were summarized and a new method for computation of these maps is presented; (2) the computer code SPECFD for solution of the three dimensional time dependent Navier-Stokes equations for compressible flow on the CYBER 203 computer is described; (3) results of two equation turbulence modeling of turbulent flow over wavy walls are presented. A modified Jones-Launder model is used in two dimensional spectral code for flow in general wavy geometries.

  6. Numerical study of a scramjet engine flow field

    NASA Technical Reports Server (NTRS)

    Drummond, J. P.; Weidner, E. H.

    1981-01-01

    A computer program has been developed to analyze the turbulent reacting flow field in a two-dimensional scramjet engine configuration. The program numerically solves the full two-dimensional Navier-Stokes and species equations in the engine inlet and combustor, allowing consideration of flow separation and possible inlet-combustor interactions. The current work represents an intermediate step towards development of a three-dimensional program to analyze actual scramjet engine flow fields. Results from the current program are presented that predict the flow field for two inlet-combustor configurations, and comparisons of the program with experiment are given to allow assessment of the modeling that is employed.

  7. Study of axisymmetric flow problems by Hele-Shaw models

    NASA Astrophysics Data System (ADS)

    Rao, P. V.; Sachan, J. S.

    1980-05-01

    Hele-Shaw models have been applied for solving two-dimensional, irrotational flow problems such as flow past bodies or radial seepage flow. The gap between the two plates is varied as a cubic parabola in the radial direction. Results are presented for seven axisymmetric models, including a cylindrical body with 60-deg conical head forms, an axisymmetric sluice entrance with a compound elliptical transition and radial flow to a well with a free surface. Pressure distributions were computed and compared with water-tunnel data, wind-tunnel data, finite-differential solutions and exact solutions.

  8. A reconstruction method of intra-ventricular blood flow using color flow ultrasound: a simulation study

    NASA Astrophysics Data System (ADS)

    Jang, Jaeseong; Ahn, Chi Young; Jeon, Kiwan; Choi, Jung-il; Lee, Changhoon; Seo, Jin Keun

    2015-03-01

    A reconstruction method is proposed here to quantify the distribution of blood flow velocity fields inside the left ventricle from color Doppler echocardiography measurement. From 3D incompressible Navier- Stokes equation, a 2D incompressible Navier-Stokes equation with a mass source term is derived to utilize the measurable color flow ultrasound data in a plane along with the moving boundary condition. The proposed model reflects out-of-plane blood flows on the imaging plane through the mass source term. For demonstrating a feasibility of the proposed method, we have performed numerical simulations of the forward problem and numerical analysis of the reconstruction method. First, we construct a 3D moving LV region having a specific stroke volume. To obtain synthetic intra-ventricular flows, we performed a numerical simulation of the forward problem of Navier-Stokes equation inside the 3D moving LV, computed 3D intra-ventricular velocity fields as a solution of the forward problem, projected the 3D velocity fields on the imaging plane and took the inner product of the 2D velocity fields on the imaging plane and scanline directional velocity fields for synthetic scanline directional projected velocity at each position. The proposed method utilized the 2D synthetic projected velocity data for reconstructing LV blood flow. By computing the difference between synthetic flow and reconstructed flow fields, we obtained the averaged point-wise errors of 0.06 m/s and 0.02 m/s for u- and v-components, respectively.

  9. Interatrial shunt flow profiles in newborn infants: a colour flow and pulsed Doppler echocardiographic study.

    PubMed Central

    Hiraishi, S; Agata, Y; Saito, K; Oguchi, K; Misawa, H; Fujino, N; Horiguchi, Y; Yashiro, K

    1991-01-01

    Interatrial shunt flow profiles in 36 normal term infants were examined serially by colour flow and pulsed Doppler echocardiographic techniques from within an hour of birth to four or five days after birth. Shunt flow across the foramen ovale was detected in 33 normal infants (92%) within an hour of birth (mean 40 minutes). The occurrence of interatrial shunting decreased with age, but a shunt signal was still detected in 17 infants (47%) on the fourth or fifth day of life, by then the ductus arteriosus had already closed in all the normal infants. The direction of interatrial shunt flow was predominantly left-to-right, but in 64% there was a coexistent small right-to-left shunt in diastole within an hour of birth; by four to five days it was found in 19%. In the six patients with persistent fetal circulation the direction of the interatrial shunt flow was predominantly right-to-left with biphasic peaks in diastole and systole at the early stage of the disease, and the period of right-to-left shunt flow during each cardiac cycle was significantly longer than that in normal infants examined within 1 hour of birth. In all patients the ductus closed before the foramen ovale. At the time of ductal closure in all patients with persistent fetal circulation right-to-left shunt flow was seen during diastole and its period was still prolonged. These findings suggest that interatrial shunting, predominantly left-to-right, is common in normal newborn infants. Evaluation of the characteristics of the interatrial shunt by Doppler echocardiography may be useful for predicting the progress of or improvement in neonates with persistent fetal circulation. Images PMID:1993129

  10. Study and Control of Scour below Pipelines under unidirectional flow

    NASA Astrophysics Data System (ADS)

    Kabiri, Shima; Hoseinzadeh Dalir, Ali

    2016-04-01

    Water and other fluids pipelines laid on sandy rivers and sea bed change flow pattern around pipelines. These changes increase the bed shear stress and the degree of confusion around the pipes and cause to create scour hole below the pipes. In this situation, the occurrence of scour below the pipelines may lead to instability, fracture and bending and even breakage where cause very severe economic and environmental harms eventually. In this research as well as studying of scour under the pipelines, the bed sill had been used as a new mechanism in order to reduce and control of scour. For this purpose, 3 pipes (smooth) with different diameters (D) were modelled in flow condition of PIC U/Uc=0.8-0.9 in the channel with 11m length, 25cm width and depth of 50 cm. Experiment has been performed in below 2 modes: 1) Scour below a smooth pipe without bed sill 2) Scour below a smooth pipe with bed sill. In the 2nd modes bed sill was located at 4 different distances (L=0,D/4,D/2,D) of downstream Of the pipe central axis. In the experiments bed sill was a barrier for spreading wake vortices and it controlled erosions of downstream. Results of this research indicated that whatever the distance of bed sill from central axis of pipe is less, there is the most influence in reducing the scour depth below pipe. In the case that bed sill had been located exactly under central axis of pipe, scour depth under pipe decreased about 100% Also in this situation with passing a long time from the beginning of examination, the pipe self-burial process occurred due to vortex creation in pipe downstream and relocation of particles toward pipe.

  11. Experimental and Theoretical Studies on Two-Phase Flows.

    NASA Astrophysics Data System (ADS)

    Koh, Christopher James

    This thesis, comprised of two parts, deals with the flow of suspensions. Part I concerns specifically with the stability of a single drop translating through a quiescent, unbounded suspending fluid at low Reynolds number. The evolution of the shape of an initially nonspherical drop as it translates is studied numerically and experimentally. For finite capillary numbers, it is shown that the drop reverts to a sphere provided that the initial deformation is small enough. However, beyond certain critical initial deformation, the drop deforms continuously. For initially prolate shapes, the drop elongates with the formation of a tail; for initially oblate shapes, the drop flattens with the formation of a cavity at its rear. Experiments extend the numerical results. It is found that initially unstable prolate drops break up into multiple droplets, while initially unstable oblate drops deform in double-emulsion drops. Part II of this thesis considers the flow of high concentration solid suspensions through a rectangular channel. By adapting the well-known Laser Doppler Anemometry, an experimental technique is developed to measure the velocity as well as particle volume fraction of the suspension. A crucial element in these experiments is the reduction of the optical turbidity of the suspension. To accomplish this goal, a systematic method based on refractive-index-matching of the two phases is employed. Experimental results show that the velocity profile is blunted while the concentration profile has a maximum near the center. The qualitative features of the experimental data compare reasonably well with theoretical predictions based on the shear-induced particle migration theory.

  12. Studying tumor metastasis by in vivo imaging and flow cytometer

    NASA Astrophysics Data System (ADS)

    Wei, Xunbin; Guo, Jin; Liu, Guangda; Li, Yan; Chen, Yun; Zhang, Li; Tan, Yuan; Chen, Tong; Gu, Zhenqin; Wang, Chen

    2009-02-01

    Liver cancer is one of the most common malignancies in the world, with approximately 1,000,000 cases reported every year. This ranges from 15,000 cases in the United States to more than a 250,000 in China. About 80% of people with primary liver cancer are male. Although two-thirds of people have advanced liver disease when they seek medical help, one third of the patients have cancer that has not progressed beyond the liver. Primary liver cancer (hepatocellular carcinoma, or HCC) is associated with liver cirrhosis 60-80% of the time. HCC may metastasize to the lung, bones, kidney, and many other organs. Surgical resection, liver transplantation, chemotherapy and radiation therapy are the foundation of current HCC therapies. However the outcomes are poor-the survival rate is almost zero for metastatic HCC patients. Molecular mechanisms of HCC metastasis need to be understood better and new therapies must be developed to selectively target to unique characteristics of HCC cell growth and metastasis. We have developed the "in vivo microscopy" to study the mechanisms that govern liver tumor cell spread through the microenvironment in vivo in real-time confocal near-infrared fluorescence imaging. A recently developed "in vivo flow cytometer" and optical imaging are used to assess liver tumor cell spreading and the circulation kinetics of liver tumor cells. A real-time quantitative monitoring of circulating liver tumor cells by the in vivo flow cytometer will be useful to assess the effectiveness of the potential therapeutic interventions.

  13. Computational and experimental study of spin coater air flow

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoguang; Liang, Faqiu; Haji-Sheikh, A.; Ghariban, N.

    1998-06-01

    An extensive 2- and 3-D analysis of air flow in a POLARISTM 2200 Microlithography Cluster spin coater was conducted using FLUENTTM Computational Fluid Dynamics (CFD) software. To supplement this analysis, direct measurement of air flow velocity was also performed using a DantecTM Hot Wire Anemometer. Velocity measurements were made along two major planes across the entire flow field in the spin coater at various operating conditions. It was found that the flow velocity at the spin coater inlet is much lower than previously assumed and quite nonuniform. Based on this observation, a pressure boundary condition rather than a velocity boundary condition was used for subsequent CFD analysis. A comparison between calculated results and experimental data shows that the 3D model accurately predicts the air flow field in the spin coater. An added advantage of this approach is that the CFD model can be easily generated from the mechanical design database and used to analyze the effect of design changes. The modeled and measured results show that the flow pattern in the spin bowl is affected by interactions between the spinning wafer, exhaust flow, and the gap between the spin head and surrounding baffle. Different operating conditions such as spin speed, inlet pressure, and exhaust pressure were found to generate substantially different flow patterns. It was also found that backflow of air could be generated under certain conditions.

  14. TOWING TANK STUDIES OF STRATIFIED FLOW OVER RIDGES AND VALLEYS

    EPA Science Inventory

    Stable atmospheric flow over a ridge and a valley was simulated in a large towing tank filled with stratified salt water. Flow visualization experiments were conducted using colored dye streamers and 10 cm high models with sinusoidal cross-sections. These experiments provided qua...

  15. Experimental study of streaming flows associated with ultrasonic levitators

    NASA Astrophysics Data System (ADS)

    Trinh, E. H.; Robey, J. L.

    1994-11-01

    Steady-state acoustic streaming flow patterns have been observed during the operation of a variety of resonant single-axis ultrasonic levitators in a gaseous environment and in the 20-37 kHz frequency range. Light sheet illumination and scattering from smoke particles have revealed primary streaming flows which display different characteristics at low and high sound pressure levels. Secondary macroscopic streaming cells around levitated samples are superimposed on the primary streaming flow pattern generated by the standing wave. These recorded flows are quite reproducible, and are qualitatively the same for a variety of levitator physical geometries. An onset of flow instability can also be recorded in nonisothermal systems, such as levitated spot-heated samples when the resonance conditions are not exactly satisfied. A preliminary qualitative interpretation of these experimental results is presented in terms of the superposition of three discrete sets of circulation cells operating on different spatial scales. These relevant length scales are the acoustic wavelength, the levitated sample size, and finally the acoustic boundary layer thickness. This approach fails, however, to explain the streaming flow-field morphology around liquid drops levitated on Earth. Observation of the interaction between the flows cells and the levitated samples also suggests the existence of a steady-state torque induced by the streaming flows.

  16. Numerical study of sound propagation in a jet flow

    NASA Technical Reports Server (NTRS)

    Padula, S. L.; Liu, C. H.

    1975-01-01

    An improved computer oriented solution method for problems involving the propagation of sound through a nonuniform jet flow is developed. The method seeks to optimize the use of computer resources such as core storage space and central memory time. Complete formulation details are presented for a jet flow model consisting of a fixed point source on the jet center line in the potential core.

  17. Blood flow in microvascular networks: A study in nonlinear biology

    PubMed Central

    Geddes, John B.; Carr, Russell T.; Wu, Fan; Lao, Yingyi; Maher, Meaghan

    2010-01-01

    Plasma skimming and the Fahraeus–Lindqvist effect are well-known phenomena in blood rheology. By combining these peculiarities of blood flow in the microcirculation with simple topological models of microvascular networks, we have uncovered interesting nonlinear behavior regarding blood flow in networks. Nonlinearity manifests itself in the existence of multiple steady states. This is due to the nonlinear dependence of viscosity on blood cell concentration. Nonlinearity also appears in the form of spontaneous oscillations in limit cycles. These limit cycles arise from the fact that the physics of blood flow can be modeled in terms of state dependent delay equations with multiple interacting delay times. In this paper we extend our previous work on blood flow in a simple two node network and begin to explore how topological complexity influences the dynamics of network blood flow. In addition we present initial evidence that the nonlinear phenomena predicted by our model are observed experimentally. PMID:21198135

  18. Application of full field optical studies for pulsatile flow in a carotid artery phantom

    PubMed Central

    Nemati, M.; Loozen, G. B.; van der Wekken, N.; van de Belt, G.; Urbach, H. P.; Bhattacharya, N.; Kenjeres, S.

    2015-01-01

    A preliminary comparative measurement between particle imaging velocimetry (PIV) and laser speckle contrast analysis (LASCA) to study pulsatile flow using ventricular assist device in a patient-specific carotid artery phantom is reported. These full-field optical techniques have both been used to study flow and extract complementary parameters. We use the high spatial resolution of PIV to generate a full velocity map of the flow field and the high temporal resolution of LASCA to extract the detailed frequency spectrum of the fluid pulses. Using this combination of techniques a complete study of complex pulsatile flow in an intricate flow network can be studied. PMID:26504652

  19. Studies of fluid flow indicators, Pacific margin of Costa Rica

    SciTech Connect

    Silver, E.; McAdoo, B.; Langseth, M.; Orange, D.

    1996-12-31

    Seismic reflection profiles off Costa Rica image a decrease in thickness of the underthrust sedimentary section from the Middle America Trench, implying a significant reduction of porosity in the outer 3-5 km from the trench and a source of vent water through the wedge. We encountered no evidence of discrete fluid venting over the outer 3-5 km of this margin from dives using the ALVIN submersible or from heat flow measurements (based on absence of chemosynthetic vent communities and heat flow anomalies in this zone). Vent communities occur farther upslope, associated with a series of out-of-sequence thrusts, with two mud diapirs, and a mid-slope canyon. We infer that fracture permeability dominates in the out-of-sequence thrusts, upflow of fluid-rich muds in the diapir, and focusing of fluid flow in the canyon. Over 100 heat flow observations on the wedge and incoming COCOS plate showed a broad area of anomalously low heat flow (13 mW/m{sup 2}) seaward of the frontal thrust, whereas the expected heat flow for ocean crust of early Miocene age is seven times greater. The very low regional heat flow may reflect refrigeration by vigorous sea water flow through the upper crust pillow basalts. Heat flow increases to about 30 mW/m{sup 2} throughout the lower slope to mid-slope, implying a combination of widespread fluid venting, reheating of the cooled crust and frictional heating at the base of the wedge. The lack of discrete vents over the outer 3-5 km of the margin indicates diffuse flow and likely temporal episodicity, as this region has been aseismic since 1950.

  20. Studies of fluid flow indicators, Pacific margin of Costa Rica

    SciTech Connect

    Silver, E.; McAdoo, B. ); Langseth, M. ); Orange, D. )

    1996-01-01

    Seismic reflection profiles off Costa Rica image a decrease in thickness of the underthrust sedimentary section from the Middle America Trench, implying a significant reduction of porosity in the outer 3-5 km from the trench and a source of vent water through the wedge. We encountered no evidence of discrete fluid venting over the outer 3-5 km of this margin from dives using the ALVIN submersible or from heat flow measurements (based on absence of chemosynthetic vent communities and heat flow anomalies in this zone). Vent communities occur farther upslope, associated with a series of out-of-sequence thrusts, with two mud diapirs, and a mid-slope canyon. We infer that fracture permeability dominates in the out-of-sequence thrusts, upflow of fluid-rich muds in the diapir, and focusing of fluid flow in the canyon. Over 100 heat flow observations on the wedge and incoming COCOS plate showed a broad area of anomalously low heat flow (13 mW/m[sup 2]) seaward of the frontal thrust, whereas the expected heat flow for ocean crust of early Miocene age is seven times greater. The very low regional heat flow may reflect refrigeration by vigorous sea water flow through the upper crust pillow basalts. Heat flow increases to about 30 mW/m[sup 2] throughout the lower slope to mid-slope, implying a combination of widespread fluid venting, reheating of the cooled crust and frictional heating at the base of the wedge. The lack of discrete vents over the outer 3-5 km of the margin indicates diffuse flow and likely temporal episodicity, as this region has been aseismic since 1950.

  1. Tips for Organizing an Educational Agricultural Commodity Trading Club

    ERIC Educational Resources Information Center

    Yost, John

    2011-01-01

    Educational commodity marketing clubs have been an effective tool for producers to develop their grain and livestock marketing skills. These groups are further enhanced when the participants engage in "actual trading" versus "paper trading" techniques. When a club chooses to try actual trading, it becomes more complicated than pooling monies…

  2. 44 CFR 402.5 - Forwarding commodities previously shipped.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... previously shipped. 402.5 Section 402.5 Emergency Management and Assistance DEPARTMENT OF COMMERCE AND DEPARTMENT OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.5 Forwarding commodities previously shipped. Order T-1 applies to transportation on or discharge from ships...

  3. 44 CFR 402.5 - Forwarding commodities previously shipped.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... previously shipped. 402.5 Section 402.5 Emergency Management and Assistance DEPARTMENT OF COMMERCE AND DEPARTMENT OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.5 Forwarding commodities previously shipped. Order T-1 applies to transportation on or discharge from ships...

  4. 44 CFR 402.5 - Forwarding commodities previously shipped.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... previously shipped. 402.5 Section 402.5 Emergency Management and Assistance DEPARTMENT OF COMMERCE AND DEPARTMENT OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.5 Forwarding commodities previously shipped. Order T-1 applies to transportation on or discharge from ships...

  5. 44 CFR 402.5 - Forwarding commodities previously shipped.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... previously shipped. 402.5 Section 402.5 Emergency Management and Assistance DEPARTMENT OF COMMERCE AND DEPARTMENT OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.5 Forwarding commodities previously shipped. Order T-1 applies to transportation on or discharge from ships...

  6. 44 CFR 402.5 - Forwarding commodities previously shipped.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... previously shipped. 402.5 Section 402.5 Emergency Management and Assistance DEPARTMENT OF COMMERCE AND DEPARTMENT OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.5 Forwarding commodities previously shipped. Order T-1 applies to transportation on or discharge from ships...

  7. 7 CFR 250.63 - Commodity Supplemental Food Program.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the administration of that program in accordance with 7 CFR part 247, the regulations for that program... to local agencies for use by eligible recipients in accordance with the provisions of 7 CFR part 247... 7 Agriculture 4 2010-01-01 2010-01-01 false Commodity Supplemental Food Program. 250.63...

  8. 22 CFR 201.11 - Eligibility of commodities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Department Foreign Assets, Sanctions, Transactions and Funds Control Regulations published in 31 CFR parts 500 through 599, as from time to time amended. (h) Commodities shipped out of a free port or bonded....11 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE...

  9. 22 CFR 201.11 - Eligibility of commodities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Department Foreign Assets, Sanctions, Transactions and Funds Control Regulations published in 31 CFR parts 500 through 599, as from time to time amended. (h) Commodities shipped out of a free port or bonded....11 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE...

  10. 22 CFR 201.11 - Eligibility of commodities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Department Foreign Assets, Sanctions, Transactions and Funds Control Regulations published in 31 CFR parts 500 through 599, as from time to time amended. (h) Commodities shipped out of a free port or bonded....11 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE...

  11. 22 CFR 201.63 - Maximum prices for commodities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 201.63 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE TO... rules for sales through or out of a free port or bonded warehouse. (1) The purchase price, including transportation costs to a cooperating country, of a commodity which has passed through a free port or...

  12. 22 CFR 201.11 - Eligibility of commodities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Department Foreign Assets, Sanctions, Transactions and Funds Control Regulations published in 31 CFR parts 500 through 599, as from time to time amended. (h) Commodities shipped out of a free port or bonded....11 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE...

  13. 22 CFR 201.63 - Maximum prices for commodities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 201.63 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE TO... rules for sales through or out of a free port or bonded warehouse. (1) The purchase price, including transportation costs to a cooperating country, of a commodity which has passed through a free port or...

  14. 22 CFR 201.63 - Maximum prices for commodities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 201.63 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE TO... rules for sales through or out of a free port or bonded warehouse. (1) The purchase price, including transportation costs to a cooperating country, of a commodity which has passed through a free port or...

  15. 22 CFR 201.63 - Maximum prices for commodities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 201.63 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE TO... rules for sales through or out of a free port or bonded warehouse. (1) The purchase price, including transportation costs to a cooperating country, of a commodity which has passed through a free port or...

  16. 22 CFR 201.11 - Eligibility of commodities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Department Foreign Assets, Sanctions, Transactions and Funds Control Regulations published in 31 CFR parts 500 through 599, as from time to time amended. (h) Commodities shipped out of a free port or bonded....11 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES AND PROCEDURES APPLICABLE...

  17. 7 CFR 226.5 - Donation of commodities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 4 2011-01-01 2011-01-01 false Donation of commodities. 226.5 Section 226.5 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS CHILD AND ADULT CARE FOOD PROGRAM Assistance to States § 226.5...

  18. 7 CFR 226.5 - Donation of commodities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 4 2012-01-01 2012-01-01 false Donation of commodities. 226.5 Section 226.5 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS CHILD AND ADULT CARE FOOD PROGRAM Assistance to States § 226.5...

  19. 7 CFR 226.5 - Donation of commodities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 4 2013-01-01 2013-01-01 false Donation of commodities. 226.5 Section 226.5 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS CHILD AND ADULT CARE FOOD PROGRAM Assistance to States § 226.5...

  20. 7 CFR 226.5 - Donation of commodities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 4 2014-01-01 2014-01-01 false Donation of commodities. 226.5 Section 226.5 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS CHILD AND ADULT CARE FOOD PROGRAM Assistance to States § 226.5...