Application of material flow analysis to estimate the efficiency of e-waste management systems: the case of Lithuania.

PubMed

Gurauskiene, Inga; Stasiskiene, Zaneta

2011-07-01

Electrical and electronic equipment (EEE) has penetrated everyday life. The EEE industry is characterized by a rapid technological change which in turn prompts consumers to replace EEE in order to keep in step with innovations. These factors reduce an EEE life span and determine the exponential growth of the amount of obsolete EEE as well as EEE waste (e-waste). E-waste management systems implemented in countries of the European Union (EU) are not able to cope with the e-waste problem properly, especially in the new EU member countries. The analysis of particular e-waste management systems is essential in evaluation of the complexity of these systems, describing and quantifying the flows of goods throughout the system, and all the actors involved in it. The aim of this paper is to present the research on the regional agent based material flow analysis in e-waste management systems, as a measure to reveal the potential points for improvement. Material flow analysis has been performed as a flow of goods (EEE). The study has shown that agent-based EEE flow analysis incorporating a holistic and life cycle thinking approach in national e-waste management systems gives a broader view to the system than a common administrative one used to cover. It helps to evaluate the real efficiency of e-waste management systems and to identify relevant impact factors determining the current operation of the system.

Hidden flows and waste processing--an analysis of illustrative futures.

PubMed

Schiller, F; Raffield, T; Angus, A; Herben, M; Young, P J; Longhurst, P J; Pollard, S J T

2010-12-14

An existing materials flow model is adapted (using Excel and AMBER model platforms) to account for waste and hidden material flows within a domestic environment. Supported by national waste data, the implications of legislative change, domestic resource depletion and waste technology advances are explored. The revised methodology offers additional functionality for economic parameters that influence waste generation and disposal. We explore this accounting system under hypothetical future waste and resource management scenarios, illustrating the utility of the model. A sensitivity analysis confirms that imports, domestic extraction and their associated hidden flows impact mostly on waste generation. The model offers enhanced utility for policy and decision makers with regard to economic mass balance and strategic waste flows, and may promote further discussion about waste technology choice in the context of reducing carbon budgets.

Evaluation of municipal solid waste management performance by material flow analysis: Theoretical approach and case study.

PubMed

Zaccariello, Lucio; Cremiato, Raffaele; Mastellone, Maria Laura

2015-10-01

The main role of a waste management plan is to define which is the combination of waste management strategies and method needed to collect and manage the waste in such a way to ensure a given set of targets is reached. Objectives have to be sustainable and realistic, consistent with the environmental policies and regulations and monitored to verify the progressive achievement of the given targets. To get the aim, the setting up and quantification of indicators can allow the measurement of efficiency of a waste management system. The quantification of efficiency indicators requires the developing of a material flow analysis over the system boundary, from waste collection to secondary materials selling, processing and disposal. The material flow analysis has been carried out with reference to a case study for which a reliable, time- and site-specific database was available. The material flow analysis allowed the evaluation of the amount of materials sent to recycling, to landfilling and to waste-to-energy, by highlighting that the sorting of residual waste can further increase the secondary materials amount. The utilisation of energy recovery to treat the low-grade waste allows the maximisation of waste diversion from landfill with a low production of hazardous ash. A preliminary economic balance has been carried out to define the gate fee of the waste management system that was in the range of 84-145 € t(-1) without including the separate collection cost. The cost of door-by-door separate collection, designed to ensure the collection of five separate streams, resulted in 250 € t(-1) ±30%. © The Author(s) 2015.

Materials flow analysis of neodymium, status of rare earth metal in the Republic of Korea.

PubMed

Swain, Basudev; Kang, Leeseung; Mishra, Chinmayee; Ahn, JoongWoo; Hong, Hyun Seon

2015-11-01

Materials flow analysis of neodymium, status of rare earth elements (REEs) in the Republic of Korea has been investigated. Information from various resources like the Korean Ministry of Environment, Korea international trade association, United Nations Commodity Trade Statistics Database and from individual industry were collected and analyzed for materials flow analysis of neodymium. Demand of neodymium in the Republic of Korea for the year 2010 was 409.5 tons out of which the majority of neodymium, i.e., 68.41% was consumed by domestic electronics industry followed by medical appliances manufacturing (13.36%). The Republic Korea is one of the biggest consumer and leading exporter of these industrial products, absolutely depends on import of neodymium, as the country is lacking natural resources. The Republic of Korea has imported 325.9 tons of neodymium permanent magnet and 79.5 tons of neodymium containing equipment parts mainly for electronics, medical appliances, and heavy/light vehicles manufacturing industry. Out of which 95.4 tons of neodymium permanent magnet get exported as an intermediate product and 140.6 tons of neodymium in the form of consumable products get exported. Worldwide the neodymium is at the high end of supply chain critical metal because of increasing demand, scarcity and irreplaceable for technological application. To bring back the neodymium to supply stream the recycling of end of life neodymium-bearing waste can be a feasible option. Out of total domestic consumption, only 21.9 tons of neodymium have been collected and subsequently recycled. From material flow analysis, the requirement for an efficient recycling system and element-wise material flow management for these REEs in the Republic of Korea were realized and recommended. Copyright © 2015 Elsevier Ltd. All rights reserved.

NetFlow Dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corbet Jr., Thomas F; Beyeler, Walter E; Vanwestrienen, Dirk

NetFlow Dynamics is a web-accessible analysis environment for simulating dynamic flows of materials on model networks. Performing a simulation requires both the NetFlow Dynamics application and a network model which is a description of the structure of the nodes and edges of a network including the flow capacity of each edge and the storage capacity of each node, and the sources and sinks of the material flowing on the network. NetFlow Dynamics consists of databases for storing network models, algorithms to calculate flows on networks, and a GIS-based graphical interface for performing simulations and viewing simulation results. Simulated flows aremore » dynamic in the sense that flows on each edge of the network and inventories at each node change with time and can be out of equilibrium with boundary conditions. Any number of network models could be simulated using Net Flow Dynamics. To date, the models simulated have been models of petroleum infrastructure. The main model has been the National Transportation Fuels Model (NTFM), a network of U.S. oil fields, transmission pipelines, rail lines, refineries, tank farms, and distribution terminals. NetFlow Dynamics supports two different flow algorithms, the Gradient Flow algorithm and the Inventory Control algorithm, that were developed specifically for the NetFlow Dynamics application. The intent is to add additional algorithms in the future as needed. The ability to select from multiple algorithms is desirable because a single algorithm never covers all analysis needs. The current algorithms use a demand-driven capacity-constrained formulation which means that the algorithms strive to use all available capacity and stored inventory to meet desired flows to sinks, subject to the capacity constraints of each network component. The current flow algorithms are best suited for problems in which a material flows on a capacity-constrained network representing a supply chain in which the material supplied can be stored at each node of the network. In the petroleum models, the flowing materials are crude oil and refined products that can be stored at tank farms, refineries, or terminals (i.e. the nodes of the network). Examples of other network models that could be simulated are currency flowing in a financial network, agricultural products moving to market, or natural gas flowing on a pipeline network.« less

Material Cycles and Chemicals: Dynamic Material Flow Analysis of Contaminants in Paper Recycling.

PubMed

Pivnenko, Kostyantyn; Laner, David; Astrup, Thomas F

2016-11-15

This study provides a systematic approach for assessment of contaminants in materials for recycling. Paper recycling is used as an illustrative example. Three selected chemicals, bisphenol A (BPA), diethylhexyl phthalate (DEHP) and mineral oil hydrocarbons (MOHs), are evaluated within the paper cycle. The approach combines static material flow analysis (MFA) with dynamic material and substance flow modeling. The results indicate that phasing out of chemicals is the most effective measure for reducing chemical contamination. However, this scenario was also associated with a considerable lag phase (between approximately one and three decades) before the presence of chemicals in paper products could be considered insignificant. While improved decontamination may appear to be an effective way of minimizing chemicals in products, this may also result in lower production yields. Optimized waste material source-segregation and collection was the least effective strategy for reducing chemical contamination, if the overall recycling rates should be maintained at the current level (approximately 70% for Europe). The study provides a consistent approach for evaluating contaminant levels in material cycles. The results clearly indicate that mass-based recycling targets are not sufficient to ensure high quality material recycling.

Determination of Reaction Stoichiometries by Flow Injection Analysis.

ERIC Educational Resources Information Center

Rios, Angel; And Others

1986-01-01

Describes a method of flow injection analysis intended for calculation of complex-formation and redox reaction stoichiometries based on a closed-loop configuration. The technique is suitable for use in undergraduate laboratories. Information is provided for equipment, materials, procedures, and sample results. (JM)

A LABORATORY STUDY TO INVESTIGATE GASEOUS EMISSIONS AND SOLIDS DECOMPOSITION DURING COMPOSTING OF MUNICIPAL SOLID WASTE

EPA Science Inventory

The report gives results of a materials flow analysis performed for composting municipal solid waste (MSW) and specific biodegradable organic components of MSW. (NOTE: This work is part of an overall U.S. EPA project providing cost, energy, and materials flow information on diffe...

Comprehensive Analysis of Migration Pathways (CAMP): Contaminant Migration Pathways at Confined Dredged Material Disposal Facilities

DTIC Science & Technology

1990-09-01

fluctuating flow rates make such approximations relatively inexact. Accuracy of mass loading estimates can be improved by increasing the number of...Engler, Patin, and Theriot 1988; Patin and Baylot 1989). 26. Effluent flow from an upland CDF is highest when large quantities of water are being...dispersion in conjunction with lower flows during placement of mechanical dredged material. Interactions between sediment and water that occur during

Metal flow and temperature in direct extrusion of large-size aluminum billets

NASA Astrophysics Data System (ADS)

Valberg, Henry; Costa, André L. M.

2018-05-01

FEM-analysis is used to study thermo-mechanical conditions in aluminum rod extrusion for billets with large size corresponding to that used in industrial production. In the analysis, focus is on how the metal flow and the temperature conditions in the extrusion material is affected by the extrusion velocity in terms of the ram speed used in the extrusion process. In the study, metal flow is characterized by the deformations in extrusion subjected to a perfect grid pattern, consisting of orthogonal crossing lines, added into the longitudinal mid-plane of the initial billet. The analysis shows that metal flow in extrusion conducted at a low ram speed of 1 mms-1, is predicted significantly different from that at a high speed of 5 mms-1, or above. As regards the thermal conditions in the extrusion material, they are also predicted significantly different, at the low and the high ram speed level. A likely explanation why metal flow is different at low and high ram speeds may be that flow is altered because of the concurrent change in the temperature field within the billet.

On the impact of the elastic-plastic flow upon the process of destruction of the solenoid in a super strong pulsed magnetic field

NASA Astrophysics Data System (ADS)

Krivosheev, S. I.; Magazinov, S. G.; Alekseev, D. I.

2018-01-01

At interaction of super strong magnetic fields with a solenoid material, a specific mode of the material flow forms. To describe this process, magnetohydrodynamic approximation is traditionally used. The formation of plastic shock-waves in material in a rapidly increasing pressure of 100 GPa/μs, can significantly alter the distribution of the physical parameters in the medium and affect the flow modes. In this paper, an analysis of supporting results of numerical simulations in comparison with available experimental data is presented.

Material flow analysis for an industry - A case study in packaging

USGS Publications Warehouse

Amey, E.B.; Sandgren, K.

1996-01-01

The basic materials used in packaging are glass, metals (primarily aluminum and steel), an ever-growing range of plastics, paper and paperboard, wood, textiles for bags, and miscellaneous other materials (such as glues, inks, and other supplies). They are fabricated into rigid, semi-rigid, or flexible containers. The most common forms of these containers include cans, drums, bottles, cartons, boxes, bags, pouches, and wraps. Packaging products are, for the most part, low cost, bulky products that are manufactured close to their customers. There is virtually no import or export of packaging products. A material flow analysis can be developed that looks at all inputs to an industrial sector, inventories the losses in processing, and tracks the fate of the material after its useful life. An example is presented that identifies the material inputs to the packaging industry, and addresses the ultimate fate of the materials used. ?? 1996 International Association for Mathematical Geology.

Supply Chain Modeling for Fluorspar and Hydroflouric Acid and Implications for Further Analyses

DTIC Science & Technology

2015-04-01

Critical Materials, Volume 1 Chapter 2. Fluorspar-HF Supply Chain 4 Foreign Supply Other usesUS Supply Fluorspar Mining HF Production Downstream...analysis are listed across the top: Fluorspar Mining , HF Production, and (pro- duction of) Downstream Products (using HF). • U.S. supply is represented by...material flows from fluorspar mining , to HF production, to downstream fluorine-containing products. – Black lines are material flows included in the supply

Materials Characterisation and Analysis for Flow Simulation of Liquid Resin Infusion

NASA Astrophysics Data System (ADS)

Sirtautas, J.; Pickett, A. K.; George, A.

2015-06-01

Liquid Resin Infusion (LRI) processes including VARI and VARTM have received increasing attention in recent years, particularly for infusion of large parts, or for low volume production. This method avoids the need for costly matched metal tooling as used in Resin Transfer Moulding (RTM) and can provide fast infusion if used in combination with flow media. Full material characterisation for LRI analysis requires models for three dimensional fabric permeability as a function of fibre volume content, fabric through-thickness compliance as a function of resin pressure, flow media permeability and resin viscosity. The characterisation of fabric relaxation during infusion is usually determined from cyclic compaction tests on saturated fabrics. This work presents an alternative method to determine the compressibility by using LRI flow simulation and fitting a model to experimental thickness measurements during LRI. The flow media is usually assumed to have isotropic permeability, but this work shows greater simulation accuracy from combining the flow media with separation plies as a combined orthotropic material. The permeability of this combined media can also be determined by fitting the model with simulation to LRI flow measurements. The constitutive models and the finite element solution were validated by simulation of the infusion of a complex aerospace demonstrator part.

Gravity flow of powder in a lunar environment. Part 2: Analysis of flow initiation

NASA Technical Reports Server (NTRS)

Pariseau, W. G.

1971-01-01

A small displacement-small strain finite element technique utilizing the constant strain triangle and incremental constitutive equations for elasticplastic (media nonhardening and obeying a Coulomb yield condition) was applied to the analysis of gravity flow initiation. This was done in a V-shaped hopper containing a powder under lunar environmental conditions. Three methods of loading were examined. Of the three, the method of computing the initial state of stress in a filled hopper prior to drawdown, by adding material to the hopper layer by layer, was the best. Results of the analysis of a typical hopper problem show that the initial state of stress, the elastic moduli, and the strength parameters have an important influence on material response subsequent to the opening of the hopper outlet.

Heat Flow Measurement and Analysis of Thermal Vacuum Insulation

NASA Astrophysics Data System (ADS)

Laa, C.; Hirschl, C.; Stipsitz, J.

2008-03-01

A new kind of calorimeter has been developed at Austrian Aerospace to measure specific material parameters needed for the analysis of thermal vacuum insulation. A detailed description of the measuring device and the measurement results will be given in this paper. This calorimeter facility allows to measure the heat flow through the insulation under vacuum conditions in a wide temperature range from liquid nitrogen to ambient. Both boundary temperatures can be chosen within this range. Furthermore the insulation can be characterized at high vacuum or under degraded vacuum, the latter is simulated by using helium or nitrogen gas. The mechanisms of heat transfer have been investigated, namely infrared radiation between the reflective layers of the insulation and conduction through the interleaving spacer material. A mathematical description of the heat flow through the insulation has been derived. Based on this, the heat flow for a typical insulation material has been calculated by finite element analysis by use of the sotware tool Ansys®. Such a transient calculation is needed to determine the time to reach thermal equilibrium, which is mandatory for a proper interpretation and evaluation of the measurement. The new insulation measurement results combined with the proposed type of analysis can be applied to better understand the thermal behavior of any kind of cryogenic system.

Preliminary analyses of SIB-B radar data for recent Hawaii lava flows

NASA Technical Reports Server (NTRS)

Kaupp, V. H.; Derryberry, B. A.; Macdonald, H. C.; Gaddis, L. R.; Mouginis-Mark, P. J.

1986-01-01

The Shuttle Imaging Radar (SIR-B) experiment acquired two L-band (23 cm wavelength) radar images (at about 28 and 48 deg incidence angles) over the Kilauea Volcano area of southeastern Hawaii. Geologic analysis of these data indicates that, although aa lava flows and pyroclastic deposits can be discriminated, pahoehoe lava flows are not readily distinguished from surrounding low return materials. Preliminary analysis of data extracted from isolated flows indicates that flow type (i.e., aa or pahoehoe) and relative age can be determined from their basic statistics and illumination angle.

On accelerated flow of MHD powell-eyring fluid via homotopy analysis method

NASA Astrophysics Data System (ADS)

Salah, Faisal; Viswanathan, K. K.; Aziz, Zainal Abdul

2017-09-01

The aim of this article is to obtain the approximate analytical solution for incompressible magnetohydrodynamic (MHD) flow for Powell-Eyring fluid induced by an accelerated plate. Both constant and variable accelerated cases are investigated. Approximate analytical solution in each case is obtained by using the Homotopy Analysis Method (HAM). The resulting nonlinear analysis is carried out to generate the series solution. Finally, Graphical outcomes of different values of the material constants parameters on the velocity flow field are discussed and analyzed.

Characterizing the primary material sources and dominant erosional processes for post-fire debris-flow initiation in a headwater basin using multi-temporal terrestrial laser scanning data

USGS Publications Warehouse

Staley, Dennis M.; Waslewicz, Thad A.; Kean, Jason W.

2014-01-01

Wildfire dramatically alters the hydrologic response of a watershed such that even modest rainstorms can produce hazardous debris flows. Relative to shallow landslides, the primary sources of material and dominant erosional processes that contribute to post-fire debris-flow initiation are poorly constrained. Improving our understanding of how and where material is eroded from a watershed during a post-fire debris-flow requires (1) precise measurements of topographic change to calculate volumetric measurements of erosion and deposition, and (2) the identification of relevant morphometrically defined process domains to spatially constrain these measurements of erosion and deposition. In this study, we combine the morphometric analysis of a steep, small (0.01 km2) headwater drainage basin with measurements of topographic change using high-resolution (2.5 cm) multi-temporal terrestrial laser scanning data made before and after a post-fire debris flow. The results of the morphometric analysis are used to define four process domains: hillslope-divergent, hillslope-convergent, transitional, and channelized incision. We determine that hillslope-divergent and hillslope-convergent process domains represent the primary sources of material over the period of analysis in the study basin. From these results we conclude that raindrop-impact induced erosion, ravel, surface wash, and rilling are the primary erosional processes contributing to post-fire debris-flow initiation in the small, steep headwater basin. Further work is needed to determine (1) how these results vary with increasing drainage basin size, (2) how these data might scale upward for use with coarser resolution measurements of topography, and (3) how these results change with evolving sediment supply conditions and vegetation recovery.

Modeling the influence of river rehabilitation scenarios on bed material sediment flux in a large river over decadal timescales

USGS Publications Warehouse

Singer, Michael B.; Dunne, Thomas

2006-01-01

A stochastic flood generator and calibrated sediment transport formulae were used to assess the decadal impact of major river rehabilitation strategies on two fraction bed material sediment flux and net storage, first‐order indicators of aquatic riverine habitat, in a large river system. Model boundary conditions were modified to reflect the implementation of three major river rehabilitation strategies being considered in the Sacramento River Valley: gravel augmentation, setting back of levees, and flow alteration. Fifty 30‐year model simulations were used to compute probabilities of the response in sediment flux and net storage to these strategies. Total annual average bed material sediment flux estimates were made at six gauged river cross sections, and ∼60 km reach‐scale sediment budgets were evaluated between them. Gravel augmentation to improve spawning habitat induced gravel accumulation locally and/or downstream, depending on the added mixture. Levee setbacks to recreate the river corridor reduced flow stages for most flows and hence lowered sediment flux. Flow alteration to mimic natural flow regimes systematically decreased total annual average flux, suggesting that high‐magnitude low‐frequency transport events do not affect long‐term trends in bed material flux. The results indicate that each rehabilitation strategy reduces sediment transport in its target reaches and modulates imbalances in total annual bed material sediment budgets at the reach scale. Additional risk analysis is necessary to identify extreme conditions associated with variable hydrology that could affect rehabilitation over decades. Sensitivity analysis suggests that sorting of bed material sediment is the most important determinant of modeled transport and storage patterns.

Computational Analysis of Material Flow During Friction Stir Welding of AA5059 Aluminum Alloys

DTIC Science & Technology

2011-01-01

tool material (AISI H13 tool steel ) is modeled as an isotropic linear-elastic material. Within the analysis, the effects of some of the FSW key process...threads/m; (b) tool 598 material = AISI H13 tool steel ; (c) workpiece material = 599 AA5059; (d) tool rotation speed = 500 rpm; (e) tool travel 600 speed...the strain-hardening term is augmented to take into account for the effect of dynamic recrystallization) while the FSW tool material (AISI H13

Sinks as integrative elements of the anthropogenic metabolism

NASA Astrophysics Data System (ADS)

Kral, Ulrich; Brunner, Paul H.

2015-04-01

The anthropogenic metabolism is an open system requiring exchange of materials and energy between the anthroposphere and the environment. Material and energy flows are taken from nature and become utilized by men. After utilization, the materials either remain in the anthroposphere as recycling products, or they leave the anthroposphere as waste and emission flows. To accommodate these materials without jeopardizing human and environmental health, limited natural sinks are available; thus, man-made sinks have to be provided where natural sinks are missing or overloaded. The oral presentation (1) suggests a coherent definition of the term "sink", encompassing natural and man-made processes, (2) presents a framework to analyse and evaluate anthropogenic material flows to sinks, based on the tool substance flow analysis and impact assessment methodology, and (3) applies the framework in a case study approach for selected substances such as Copper and Lead in Vienna and Perfluorooctane sulfonate in Switzerland. Finally, the numeric results are aggregated in terms of a new indicator that specifies on a regional scale which fractions of anthropogenic material flows to sinks are acceptable. The following results are obtained: In Vienna, 99% of Cu flows to natural and man-made sinks are in accordance with accepted standards. However, the 0.7% of Cu entering urban soils and the 0.3% entering receiving waters surpass the acceptable level. In the case of Pb, 92% of all flows into sinks prove to be acceptable, but 8% are disposed of in local landfills with limited capacity. For PFOS, 96% of all flows into sinks are acceptable. 4% cannot be evaluated due to a lack of normative criteria, despite posing a risk for human health and the environment. The case studies corroborate the need and constraints of sinks to accommodate inevitable anthropogenic material flows.

Methods for forming small-volume electrical contacts and material manipulations with fluid microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-12-27

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-04-26

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microehannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-03-22

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael

2007-11-20

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael; Culbertson, Christopher T.; Whitten, William B.; Foote, Robert S.

2004-02-03

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

A new data-processing approach to study particle motion using ultrafast X-ray tomography scanner: case study of gravitational mass flow

NASA Astrophysics Data System (ADS)

Waktola, Selam; Bieberle, Andre; Barthel, Frank; Bieberle, Martina; Hampel, Uwe; Grudzień, Krzysztof; Babout, Laurent

2018-04-01

In most industrial products, granular materials are often required to flow under gravity in various kinds of silo shapes and usually through an outlet in the bottom. There are several interrelated parameters which affect the flow, such as internal friction, bulk and packing density, hopper geometry, and material type. Due to the low-spatial resolution of electrical capacitance tomography or scanning speed limitation of standard X-ray CT systems, it is extremely challenging to measure the flow velocity and possible centrifugal effects of granular materials flow effectively. However, ROFEX (ROssendorf Fast Electron beam X-ray tomography) opens new avenues of granular flow investigation due to its very high temporal resolution. This paper aims to track particle movements and evaluate the local grain velocity during silo discharging process in the case of mass flow. The study has considered the use of the Seramis material, which can also serve as a type of tracer particles after impregnation, due to its porous nature. The presented novel image processing and analysis approach allows satisfyingly measuring individual particle velocities but also tracking their lateral movement and three-dimensional rotations.

A note on scrap in the 1992 U.S. input-output tables

USGS Publications Warehouse

Swisko, George M.

2000-01-01

Introduction A key concern of industrial ecology and life cycle analysis is the disposal and recycling of scrap. One might conclude that the U.S. input-output tables are appropriate tools for analyzing scrap flows. Duchin, for instance, has suggested using input-output analysis for industrial ecology, indicating that input-output economics can trace the stocks and flows of energy and other materials from extraction through production and consumption to recycling or disposal. Lave and others use input-output tables to design life cycle assessment models for studying product design, materials use, and recycling strategies, even with the knowledge that these tables suffer from a lack of comprehensive and detailed data that may never be resolved. Although input-output tables can offer general guidance about the interdependence of economic and environmental processes, data reporting by industry and the economic concepts underlying these tables pose problems for rigorous material flow examinations. This is especially true for analyzing the output of scrap and scrap flows in the United States and estimating the amount of scrap that can be recycled. To show how data reporting has affected the values of scrap in recent input-output tables, this paper focuses on metal scrap generated in manufacturing. The paper also briefly discusses scrap that is not included in the input-output tables and some economic concepts that limit the analysis of scrap flows.

Conjugate Analysis of Two-Dimensional Ablation and Pyrolysis in Rocket Nozzles

NASA Astrophysics Data System (ADS)

Cross, Peter G.

The development of a methodology and computational framework for performing conjugate analyses of transient, two-dimensional ablation of pyrolyzing materials in rocket nozzle applications is presented. This new engineering methodology comprehensively incorporates fluid-thermal-chemical processes relevant to nozzles and other high temperature components, making it possible, for the first time, to rigorously capture the strong interactions and interdependencies that exist between the reacting flowfield and the ablating material. By basing thermal protection system engineering more firmly on first principles, improved analysis accuracy can be achieved. The computational framework developed in this work couples a multi-species, reacting flow solver to a two-dimensional material response solver. New capabilities are added to the flow solver in order to be able to model unique aspects of the flow through solid rocket nozzles. The material response solver is also enhanced with new features that enable full modeling of pyrolyzing, anisotropic materials with a true two-dimensional treatment of the porous flow of the pyrolysis gases. Verification and validation studies demonstrating correct implementation of these new models in the flow and material response solvers are also presented. Five different treatments of the surface energy balance at the ablating wall, with increasing levels of fidelity, are investigated. The Integrated Equilibrium Surface Chemistry (IESC) treatment computes the surface energy balance and recession rate directly from the diffusive fluxes at the ablating wall, without making transport coefficient or unity Lewis number assumptions, or requiring pre-computed surface thermochemistry tables. This method provides the highest level of fidelity, and can inherently account for the effects that recession, wall temperature, blowing, and the presence of ablation product species in the boundary layer have on the flowfield and ablation response. Multiple decoupled and conjugate ablation analysis studies for the HIPPO nozzle test case are presented. Results from decoupled simulations show sensitivity to the wall temperature profile used within the flow solver, indicating the need for conjugate analyses. Conjugate simulations show that the thermal response of the nozzle is relatively insensitive to the choice of the surface energy balance treatment. However, the surface energy balance treatment is found to strongly affect the surface recession predictions. Out of all the methods considered, the IESC treatment produces surface recession predictions with the best agreement to experimental data. These results show that the increased fidelity provided by the proposed conjugate ablation modeling methodology produces improved analysis accuracy, as desired.

Embrittlement and Flow Localization in Reactor Structural Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xianglin Wu; Xiao Pan; James Stubbins

2006-10-06

Many reactor components and structural members are made from metal alloys due, in large part, to their strength and ability to resist brittle fracture by plastic deformation. However, brittle fracture can occur when structural material cannot undergo extensive, or even limited, plastic deformation due to irradiation exposure. Certain irradiation conditions lead to the development of a damage microstructure where plastic flow is limited to very small volumes or regions of material, as opposed to the general plastic flow in unexposed materials. This process is referred to as flow localization or plastic instability. The true stress at the onset of neckingmore » is a constant regardless of the irradiation level. It is called 'critical stress' and this critical stress has strong temperature dependence. Interrupted tensile testes of 316L SS have been performed to investigate the microstructure evolution and competing mechanism between mechanic twinning and planar slip which are believed to be the controlling mechanism for flow localization. Deformation twinning is the major contribution of strain hardening and good ductility for low temperatures, and the activation of twinning system is determined by the critical twinning stress. Phases transform and texture analyses are also discussed in this study. Finite element analysis is carried out to complement the microstructural analysis and for the prediction of materaials performance with and without stress concentration and irradiation.« less

IO-MFA and Thermodynamic Approach for Metal Recycling

NASA Astrophysics Data System (ADS)

Nakajima, Kenichi; Matsubae, Kazuyo; Kondo, Yasushi; Nakamura, Shinichiro; Nagasaka, Tetsuya

Recently, the issue of sustainable resource management has been increasingly recognized. In order to increase resource efficiency, Castro et al. (2004) pointed out an importance to understand the interconnections between the materials' processing routes and their thermodynamic constraints, and discussed losses due to contaminations during recycling. One of the dominant solutions to avoid such losses or contaminants is knowledge about the substance flows in material cycles. Material flow analysis (MFA) is a powerful tool to understand the resource consumption and material cycle in the national economy. Some advanced MFA studies discussed the complex web of metal flows and their linkages (Nakamura et al. 2007, 2008). Discussions on the limitations of impurity removal and the recoverability of elements in the recycling of EoL metal products, however, have been insufficient even in conventional MFA studies.

Flow Curve Analysis of 17-4 PH Stainless Steel under Hot Compression Test

NASA Astrophysics Data System (ADS)

Mirzadeh, Hamed; Najafizadeh, Abbas; Moazeny, Mohammad

2009-12-01

The hot compression behavior of a 17-4 PH stainless steel (AISI 630) has been investigated at temperatures of 950 °C to 1150 °C and strain rates of 10-3 to 10 s-1. Glass powder in the Rastegaev reservoirs of the specimen was used as a lubricant material. A step-by-step procedure for data analysis in the hot compression test was given. The work hardening rate analysis was performed to reveal if dynamic recrystallization (DRX) occurred. Many samples exhibited typical DRX stress-strain curves with a single peak stress followed by a gradual fall toward the steady-state stress. At low Zener-Hollomon ( Z) parameter, this material showed a new DRX flow behavior, which was called multiple transient steady state (MTSS). At high Z, as a result of adiabatic deformation heating, a drop in flow stress was observed. The general constitutive equations were used to determine the hot working constants of this material. Moreover, after a critical discussion, the deformation activation energy of 17-4 PH stainless steel was determined as 337 kJ/mol.

Flow-controlled magnetic particle manipulation

DOEpatents

Grate, Jay W [West Richland, WA; Bruckner-Lea, Cynthia J [Richland, WA; Holman, David A [Las Vegas, NV

2011-02-22

Inventive methods and apparatus are useful for collecting magnetic materials in one or more magnetic fields and resuspending the particles into a dispersion medium, and optionally repeating collection/resuspension one or more times in the same or a different medium, by controlling the direction and rate of fluid flow through a fluid flow path. The methods provide for contacting derivatized particles with test samples and reagents, removal of excess reagent, washing of magnetic material, and resuspension for analysis, among other uses. The methods are applicable to a wide variety of chemical and biological materials that are susceptible to magnetic labeling, including, for example, cells, viruses, oligonucleotides, proteins, hormones, receptor-ligand complexes, environmental contaminants and the like.

A production-theory-based framework for analysing recycling systems in the e-waste sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt, Mario

2005-07-15

Modern approaches in the production theory of business and management economics propose that objects (e.g. materials) be divided into good, bad or neutral. In transformation processes such as occur in production or recycling this makes it possible to distinguish stringently between the economic revenue of a process and the economic and ecological expenditures for it. This approach can be transferred to entire systems of processes in order to determine the system revenue and the system expenditure. Material flow nets or graphs are used for this purpose. In complex material flow systems it becomes possible to calculate not only the costs,more » but also the direct and indirect environmental impacts of an individual process or a system revenue (for example a product or the elimination of waste) consistently. The approach permits a stringent analysis as well as different analysis perspectives of a material flow system. It is particularly suitable for closed-loop economic systems in which material backflows occur. With the aid of an example developed jointly with Hewlett Packard Europe, the paper outlines how this approach can be employed in the field of e-waste management.« less

Reduced viscosity interpreted for fluid/gas mixtures

NASA Technical Reports Server (NTRS)

Lewis, D. H.

1981-01-01

Analysis predicts decrease in fluid viscosity by comparing pressure profile of fluid/gas mixture with that of power-law fluid. Fluid is taken to be viscous, non-Newtonian, and incompressible; the gas to be ideal; the flow to be inertia-free, isothermal, and one dimensional. Analysis assists in design of flow systems for petroleum, coal, polymers, and other materials.

Modes of sediment transport in channelized water flows with ramifications to the erosion of the Martian outflow channels

NASA Technical Reports Server (NTRS)

Komar, P. D.

1980-01-01

The paper discusses application to Martian water flows of the criteria that determine which grain-size ranges are transported as bed load, suspension, and wash load. The results show nearly all sand-sized material and finer would have been transported as wash load and that basalt pebbles and even cobbles could have been transported at rapid rates of suspension. An analysis of the threshold of sediment motion on Mars further indicates that the flows would have been highly competent, the larger flows having been able to transport boulder-sized material. Comparisons with terrestrial rivers which transport hyperconcentration levels of sediments suggest that the Martian water flows could have achieved sediment concentrations up to 70% in weight. Although it is possible that flows could have picked up enough sediment to convert to pseudolaminar mud flows, they probably remained at hyperconcentration levels and fully turbulent in flow character.

Development of a Thin Film Primary Surface Heat Exchanger for Advanced Power Cycles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allison, Tim; Beck, Griffin; Bennett, Jeffrey

This project objective is to develop a high-temperature design upgrade for an existing primary surface heat exchanger so that the redesigned hardware is capable of operation in CO 2 at temperatures up to 1,510°F (821°C) and pressure differentials up to 130 psi (9 bar). The heat exchanger is proposed for use as a recuperator in an advanced low-pressure oxy-fuel Brayton cycle that is predicted to achieve over 50% thermodynamic efficiency, although the heat exchanger could also be used in other high-temperature, low-differential pressure cycles. This report describes the progress to date, which includes continuing work performed to select and testmore » new candidate materials for the recuperator redesign, final mechanical and thermal performance analysis results of various redesign concepts, and the preliminary design of a test loop for the redesigned recuperator including a budgetary estimate for detailed test loop design, procurement, and test operation. A materials search was performed in order to investigate high-temperature properties of many candidate materials, including high-temperature strength and nickel content. These properties were used to rank the candidate materials, resulting in a reduced list of nine materials for corrosion testing. Multiple test rigs were considered and analyzed for short-term corrosion testing and Thermal Gravimetric Analysis (TGA) was selected as the most cost-effective option for evaluating corrosion resistance of the candidate materials. In addition, tantalum, niobium, and chromium coatings were identified as potential options for increased corrosion resistance. The test results show that many materials exhibit relatively low weight gain rates, and that niobium and tantalum coatings may improve corrosion resistance for many materials, while chromium coatings appear to oxidize and debond quickly. Metallurgical analysis of alloys was also performed, showing evidence of intergranular attack in 282 that may cause long-term reliability problems in CO 2 service at these temperatures. However, long-term testing in a flowing environment is recommended in order to understand accurately the severity of the attack. Detailed economic modeling of the existing air cycle recuperator and CO 2 cycle recuperator options was also completed, including costs for material, fabrication, fuel, maintenance, and operation. The analysis results show that the increased capital cost for high-temperature materials may be offset by higher cycle efficiencies, decreasing the overall lifetime cost of the system. The economic analysis also examines costs associated with increased pressure drop and material changes for two redesign options. These results show that, even with slightly reduced performance and/or higher material costs, the lifetime cost per energy production may still be reduced by over 12%. The existing recuperator design information was provided by Solar Turbines, Inc. via several models, drawings, and design handoff meetings. Multiple fluid/thermal and structural models were created in order to analyze critical recuperator performance and mechanical strength in critical areas throughout the redesign process. These models were analyzed for a baseline condition (consistent with current Mercury 50 operation) for validation purposes. Results are presented for heat transfer coefficients and pressure drops, matching well with the existing operational data. Simulation of higher-temperature CO 2 conditions was also performed, showing a slight expected increase in both heat transfer and pressure drop. Mechanical analysis results for critical areas on the cross-flow and counter-flow sheets have also been obtained for air and CO 2 cases. These results show similar stresses in both cases but significantly reduced safety factors for the CO 2 case due to reduced yield and creep rupture strengths of alloy 625 at the higher temperatures. A concept brainstorm session and initial down-selection were completed in order to identify promising redesign options for further analysis. Detailed analysis of all promising redesign options was performed via finite element and computational fluid dynamic simulations in order to characterize mechanical and thermal-fluid performance of each option. These options included material change, various sheet thickness configurations, pitch and phasing of cross-flow and counter-flow sheets, and separator sheets. The analysis results have identified two viable redesign options that maintain existing safety margins optimally through a material change to Haynes 282 and (A) sheet thickness increases of 40% on the counter-flow sheet and 75% on the hot side cross-flow corrugation sheet or (B) addition of a separator sheet in the counter-flow section while maintaining the original counter-flow sheet thickness and increasing the cross-flow corrugation sheet thickness by 90% to account for the increase in cell height. While both options satisfy mechanical stress constraints, the separator sheet design has a higher part count, slightly reduced heat transfer, and slightly higher pressure drop than the first option and is not preferred. Finally, several test loop concepts have been developed for different full-scale and reduced-scale recuperator testing options. For each option, various loop components, such as heat exchangers, valves, heaters, and compressors, were evaluated in an effort to maximize utilization of existing resources. All concepts utilize an existing 3-MW CO 2 compressor, heater, and loop coolers, but the concepts vary by incorporating different amounts of new equipment for achieving various flow rates (all concepts operate at design pressure and temperature). The third concept achieves a 1 kg/s test without purchasing any costly equipment (coolers, heaters, blowers, etc.). Since the stacked cell design of the recuperator results in the same flow conditions at each core cell (even for a reduced-scale test). Thus, test loop Concept #3 was selected for the preliminary design. This loop design is detailed within the report, culminating in a budgetary estimate of $1,013,000.00 for the detailed design, construction, commissioning, and operation of a high-temperature recuperator test loop.« less

Total materials consumption; an estimation methodology and example using lead; a materials flow analysis

USGS Publications Warehouse

Biviano, Marilyn B.; Wagner, Lorie A.; Sullivan, Daniel E.

1999-01-01

Materials consumption estimates, such as apparent consumption of raw materials, can be important indicators of sustainability. Apparent consumption of raw materials does not account for material contained in manufactured products that are imported or exported and may thus under- or over-estimate total consumption of materials in the domestic economy. This report demonstrates a methodology to measure the amount of materials contained in net imports (imports minus exports), using lead as an example. The analysis presents illustrations of differences between apparent and total consumption of lead and distributes these differences into individual lead-consuming sectors.

Flow-induced vibration and fretting-wear damage in a moisture separator reheater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pettigrew, M.J.; Taylor, C.E.; Fisher, N.J.

1996-12-01

Tube failures due to excessive flow-induced vibration were experienced in the tube bundles of moisture separator reheaters in a BWR nuclear station. This paper presents the results of a root cause analysis and covers recommendations for continued operation and for replacement tube bundles. The following tasks are discussed: tube failure analysis; flow velocity distribution calculations; flow-induced vibration analysis with particular emphasis on finned-tubes; fretting-wear testing of a tube and tube-support material combination under simulated operating conditions; field measurements of flow-induced vibration; and development of vibration specifications for replacement tube bundles. The effect of transient operating conditions and of other operationalmore » changes such as tube fouling were considered in the analysis. This paper outlines a typical field problem and illustrates the application of flow-induced vibration technology for the solution of a practical problem.« less

Pulsed Neurton Elemental On-Line Material Analyzer

DOEpatents

Vourvopoulos, George

2002-08-20

An on-line material analyzer which utilizes pulsed neutron generation in order to determine the composition of material flowing through the apparatus. The on-line elemental material analyzer is based on a pulsed neutron generator. The elements in the material interact with the fast and thermal neutrons produced from the pulsed generator. Spectra of gamma-rays produced from fast neutrons interacting with elements of the material are analyzed and stored separately from spectra produced from thermal neutron reactions. Measurements of neutron activation takes place separately from the above reactions and at a distance from the neutron generator. A primary passageway allows the material to flow through at a constant rate of speed and operators to provide data corresponding to fast and thermal neutron reactions. A secondary passageway meters the material to allow for neutron activation analysis. The apparatus also has the capability to determine the density of the flowed material. Finally, the apparatus continually utilizes a neutron detector in order to normalize the yield of the gamma ray detectors and thereby automatically calibrates and adjusts the spectra data for fluctuations in neutron generation.

The Montaguto earth flow: nine years of observation and analysis

USGS Publications Warehouse

Guerriero, L.; Revellino, R; Grelle, G.; Diodato, N; Guadagno, F.M.; Coe, Jeffrey A.

2016-01-01

This paper summarizes the methods, results, and interpretation of analyses carried out between 2006 and 2015 at the Montaguto earth flow in southern Italy. We conducted a multi-temporal analysis of earth-flow activity to reconstruct the morphological and structural evolution of the flow. Data from field mapping were combined with a geometric reconstruction of the basal slip surface in order to investigate relations between basal-slip surface geometry and deformation styles of earth-flow material. Moreover, we reconstructed the long-term pattern of earth-flow movement using both historical observations and modeled hydrologic and climatic data. Hydrologic and climatic data were used to develop a Landslide Hydrological Climatological (LHC) indicator model.

Experiment study on sediment erosion of Pelton turbine flow passage component material

NASA Astrophysics Data System (ADS)

Liu, J.; Lu, L.; Zhu, L.

2012-11-01

A rotating and jet experiment system with high flow velocity is designed to study the anti-erosion performance of materials. The resultant velocity of the experiment system is high to 120 m/s. The anti-erosion performance of materials used in needle and nozzle and bucket of Pelton turbine, which is widely used in power station with high head and little discharge, was studied in detail by this experiment system. The experimental studies were carried with different resultant velocities and sediment concentrations. Multiple linear regression analysis method was applied to get the exponents of velocity and sediment concentration. The exponents for different materials are different. The exponents of velocity ranged from 3 to 3.5 for three kinds of material. And the exponents of sediment concentration ranged from 0.97 to 1.03 in this experiment. The SEM analysis on the erosion surface of different materials was also carried. On the erosion condition with high resultant impact velocity, the selective cutting loss of material is the mainly erosion mechanism for metal material.

Material Flow Analysis as a Tool to improve Waste Management Systems: The Case of Austria.

PubMed

Allesch, Astrid; Brunner, Paul H

2017-01-03

This paper demonstrates the power of material flow analysis (MFA) for designing waste management (WM) systems and for supporting decisions with regards to given environmental and resource goals. Based on a comprehensive case study of a nationwide WM-system, advantages and drawbacks of a mass balance approach are discussed. Using the software STAN, a material flow system comprising all relevant inputs, stocks and outputs of wastes, products, residues, and emissions is established and quantified. Material balances on the level of goods and selected substances (C, Cd, Cr, Cu, Fe, Hg, N, Ni, P, Pb, Zn) are developed to characterize this WM-system. The MFA results serve well as a base for further assessments. Based on given goals, stakeholders engaged in this study selected the following seven criteria for evaluating their WM-system: (i) waste input into the system, (ii) export of waste (iii) gaseous emissions from waste treatment plants, (iv) long-term gaseous and liquid emissions from landfills, (v) waste being recycled, (vi) waste for energy recovery, (vii) total waste landfilled. By scenario analysis, strengths and weaknesses of different measures were identified. The results reveal the benefits of a mass balance approach due to redundancy, data consistency, and transparency for optimization, design, and decision making in WM.

Debris flow run-out simulation and analysis using a dynamic model

NASA Astrophysics Data System (ADS)

Melo, Raquel; van Asch, Theo; Zêzere, José L.

2018-02-01

Only two months after a huge forest fire occurred in the upper part of a valley located in central Portugal, several debris flows were triggered by intense rainfall. The event caused infrastructural and economic damage, although no lives were lost. The present research aims to simulate the run-out of two debris flows that occurred during the event as well as to calculate via back-analysis the rheological parameters and the excess rain involved. Thus, a dynamic model was used, which integrates surface runoff, concentrated erosion along the channels, propagation and deposition of flow material. Afterwards, the model was validated using 32 debris flows triggered during the same event that were not considered for calibration. The rheological and entrainment parameters obtained for the most accurate simulation were then used to perform three scenarios of debris flow run-out on the basin scale. The results were confronted with the existing buildings exposed in the study area and the worst-case scenario showed a potential inundation that may affect 345 buildings. In addition, six streams where debris flow occurred in the past and caused material damage and loss of lives were identified.

Challenges in the size analysis of a silica nanoparticle mixture as candidate certified reference material

NASA Astrophysics Data System (ADS)

Kestens, Vikram; Roebben, Gert; Herrmann, Jan; Jämting, Åsa; Coleman, Victoria; Minelli, Caterina; Clifford, Charles; De Temmerman, Pieter-Jan; Mast, Jan; Junjie, Liu; Babick, Frank; Cölfen, Helmut; Emons, Hendrik

2016-06-01

A new certified reference material for quality control of nanoparticle size analysis methods has been developed and produced by the Institute for Reference Materials and Measurements of the European Commission's Joint Research Centre. The material, ERM-FD102, consists of an aqueous suspension of a mixture of silica nanoparticle populations of distinct particle size and origin. The characterisation relied on an interlaboratory comparison study in which 30 laboratories of demonstrated competence participated with a variety of techniques for particle size analysis. After scrutinising the received datasets, certified and indicative values for different method-defined equivalent diameters that are specific for dynamic light scattering (DLS), centrifugal liquid sedimentation (CLS), scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy (AFM), particle tracking analysis (PTA) and asymmetrical-flow field-flow fractionation (AF4) were assigned. The value assignment was a particular challenge because metrological concepts were not always interpreted uniformly across all participating laboratories. This paper presents the main elements and results of the ERM-FD102 characterisation study and discusses in particular the key issues of measurand definition and the estimation of measurement uncertainty.

Comparative Kinetic Analysis of Closed-Ended and Open-Ended Porous Sensors

NASA Astrophysics Data System (ADS)

Zhao, Yiliang; Gaur, Girija; Mernaugh, Raymond L.; Laibinis, Paul E.; Weiss, Sharon M.

2016-09-01

Efficient mass transport through porous networks is essential for achieving rapid response times in sensing applications utilizing porous materials. In this work, we show that open-ended porous membranes can overcome diffusion challenges experienced by closed-ended porous materials in a microfluidic environment. A theoretical model including both transport and reaction kinetics is employed to study the influence of flow velocity, bulk analyte concentration, analyte diffusivity, and adsorption rate on the performance of open-ended and closed-ended porous sensors integrated with flow cells. The analysis shows that open-ended pores enable analyte flow through the pores and greatly reduce the response time and analyte consumption for detecting large molecules with slow diffusivities compared with closed-ended pores for which analytes largely flow over the pores. Experimental confirmation of the results was carried out with open- and closed-ended porous silicon (PSi) microcavities fabricated in flow-through and flow-over sensor configurations, respectively. The adsorption behavior of small analytes onto the inner surfaces of closed-ended and open-ended PSi membrane microcavities was similar. However, for large analytes, PSi membranes in a flow-through scheme showed significant improvement in response times due to more efficient convective transport of analytes. The experimental results and theoretical analysis provide quantitative estimates of the benefits offered by open-ended porous membranes for different analyte systems.

Influence of deposition of fine plant debris in river floodplain shrubs on flood flow conditions - The Warta River case study

NASA Astrophysics Data System (ADS)

Mazur, Robert; Kałuża, Tomasz; Chmist, Joanna; Walczak, Natalia; Laks, Ireneusz; Strzeliński, Paweł

2016-08-01

This paper presents problems caused by organic material transported by flowing water. This material is usually referred to as plant debris or organic debris. Its composition depends on the characteristic of the watercourse. For lowland rivers, the share of the so-called small organic matter in plant debris is considerable. This includes both various parts of water plants and floodplain vegetation (leaves, stems, blades of grass, twigs, etc.). During floods, larger woody debris poses a significant risk to bridges or other water engineering structures. It may cause river jams and may lead to damming of the flowing water. This, in turn, affects flood safety and increases flood risk in river valleys, both directly and indirectly. The importance of fine plant debris for the phenomenon being studied comes down to the hydrodynamic aspect (plant elements carried by water end up on trees and shrubs, increase hydraulic flow resistance and contribute to the nature of flow through vegetated areas changed from micro-to macro-structural). The key part of the research problem under analysis was to determine qualitative and quantitative debris parameters and to establish the relationship between the type of debris and the type of land use of river valleys (crop fields, meadows and forested river sections). Another problem was to identify parameters of plant debris for various flow conditions (e.g. for low, medium and flood flows). The research also included an analysis of the materials deposited on the structure of shrubs under flood flow conditions during the 2010 flood on the Warta River.

Historical Analysis of C-130E Resources

DTIC Science & Technology

1977-07-01

DOCUMENTATION SEARCH AND COLLECTION FLOW 24 DIAGRAM 6. DATA ANALYSIS FLOW DIAGRAM TASK IV 29 7. C-130 INVENTORY BY CONFIGURATION 40 8. C-130 MISSION...RESORCE RESOURCES....EOUCE .’." * ESURE :;. 400 ................... - ., -...... ’.. ... ".......... ... ’... ’" SYSTEM DESIGN PERFORMANCE 4 , OPERATIO ...Force inventory , the control of the human and material resources crosses several functions and commands. Seldom are the initial estimates verified

Advancement and Implementation of Integrated Computational Materials Engineering (ICME) for Aerospace Applications

DTIC Science & Technology

2010-03-01

of sub-routines Thermal history • Abaqus FEM engine mature applied within ABAQUS Residual stress & Distortion • Unknown maturity for HTC • Focused...investment. The committee’s ICME vision is comprehensive, expansive , and involves the entire materials community. The scope of this white paper is...Software • Continuum FEM for fluid flow, heat Mold Fill • FEM implementation mature flow and stress analysis Thermal & mushy zone history • Needs

Clinical evaluation of flowable resins in non-carious cervical lesions: two-year results.

PubMed

Celik, Cigdem; Ozgünaltay, Gül; Attar, Nuray

2007-01-01

This study evaluated the two-year clinical performance of one microhybrid composite and three different types of flowable resin materials in non-carious cervical lesions. A total of 252 noncarious cervical lesions were restored in 37 patients (12 male, 25 female) with Admira Flow, Dyract Flow, Filtek Flow and Filtek Z250, according to manufacturers' instructions. All the restorations were placed by one operator, and two other examiners evaluated the restorations clinically within one week after placement and after 6, 12, 18 and 24 months, using modified USPHS criteria. At the end of 24 months, 172 restorations were evaluated in 26 patients, with a recall rate of 68%. Statistical analysis was completed using the Pearson Chi-square and Fisher-Freeman-Halton tests (p < 0.05). Additionally, survival rates were analyzed with the Kaplan-Meier estimator and the Log-Rank test (p < 0.05). The Log-Rank test indicated statistically significant differences between the survival rates of Dyract Flow/Admira Flow and Dyract Flow/Filtek Z250 (p < 0.05). While there was a statistically significant difference between Dyract Flow and the other materials for color match at 12 and 18 months, no significant difference was observed among all of the materials tested at 24 months. Significant differences were revealed between Filtek Z250 and the other materials for marginal adaptation at 18 and 24 months (p < 0.05). With respect to marginal discoloration, secondary caries, surface texture and anatomic form, no significant differences were found between the resin materials (p > 0.05). It was concluded that different types of resin materials demonstrated acceptable clinical performance in non-carious cervical lesions, except for the retention rates of the Dyract Flow restorations.

Interdisciplinary Pathways for Urban Metabolism Research

NASA Astrophysics Data System (ADS)

Newell, J. P.

2011-12-01

With its rapid rise as a metaphor to express coupled natural-human systems in cities, the concept of urban metabolism is evolving into a series of relatively distinct research frameworks amongst various disciplines, with varying definitions, theories, models, and emphases. In industrial ecology, housed primarily within the disciplinary domain of engineering, urban metabolism research has focused on quantifying material and energy flows into, within, and out of cities, using methodologies such as material flow analysis and life cycle assessment. In the field of urban ecology, which is strongly influenced by ecology and urban planning, research focus has been placed on understanding and modeling the complex patterns and processes of human-ecological systems within urban areas. Finally, in political ecology, closely aligned with human geography and anthropology, scholars theorize about the interwoven knots of social and natural processes, material flows, and spatial structures that form the urban metabolism. This paper offers three potential interdisciplinary urban metabolism research tracks that might integrate elements of these three "ecologies," thereby bridging engineering and the social and physical sciences. First, it presents the idea of infrastructure ecology, which explores the complex, emergent interdependencies between gray (water and wastewater, transportation, etc) and green (e.g. parks, greenways) infrastructure systems, as nested within a broader socio-economic context. For cities to be sustainable and resilient over time-space, the theory follows, these is a need to understand and redesign these infrastructure linkages. Second, there is the concept of an urban-scale carbon metabolism model which integrates consumption-based material flow analysis (including goods, water, and materials), with the carbon sink and source dynamics of the built environment (e.g. buildings, etc) and urban ecosystems. Finally, there is the political ecology of the material urban metabolism, which adds spatial differentiation to materials flows and form, as well as a focus on equity, access, and governance dimensions of the urban metabolism.

Computational domain discretization in numerical analysis of flow within granular materials

NASA Astrophysics Data System (ADS)

Sosnowski, Marcin

2018-06-01

The discretization of computational domain is a crucial step in Computational Fluid Dynamics (CFD) because it influences not only the numerical stability of the analysed model but also the agreement of obtained results and real data. Modelling flow in packed beds of granular materials is a very challenging task in terms of discretization due to the existence of narrow spaces between spherical granules contacting tangentially in a single point. Standard approach to this issue results in a low quality mesh and unreliable results in consequence. Therefore the common method is to reduce the diameter of the modelled granules in order to eliminate the single-point contact between the individual granules. The drawback of such method is the adulteration of flow and contact heat resistance among others. Therefore an innovative method is proposed in the paper: single-point contact is extended to a cylinder-shaped volume contact. Such approach eliminates the low quality mesh elements and simultaneously introduces only slight distortion to the flow as well as contact heat transfer. The performed analysis of numerous test cases prove the great potential of the proposed method of meshing the packed beds of granular materials.

Pulsed single-blow regenerator testing

NASA Technical Reports Server (NTRS)

Oldson, J. C.; Knowles, T. R.; Rauch, J.

1992-01-01

A pulsed single-blow method has been developed for testing of Stirling regenerator materials performance. The method uses a tubular flow arrangement with a steady gas flow passing through a regenerator matrix sample that packs the flow channel for a short distance. A wire grid heater spanning the gas flow channel is used to heat a plug of gas by approximately 2 K for approximately 350 ms. Foil thermocouples monitor the gas temperature entering and leaving the sample. Data analysis based on a 1D incompressible-flow thermal model allows the extraction of Stanton number. A figure of merit involving heat transfer and pressure drop is used to present results for steel screens and steel felt. The observations show a lower figure of merit for the materials tested than is expected based on correlations obtained by other methods.

Preliminary Design of Industrial Symbiosis of Smes Using Material Flow Cost Accounting (MFCA) Method

NASA Astrophysics Data System (ADS)

Astuti, Rahayu Siwi Dwi; Astuti, Arieyanti Dwi; Hadiyanto

2018-02-01

Industrial symbiosis is a collaboration of several industries to share their necessities such material, energy, technology as well as waste management. As a part of industrial ecology, in principle, this system attempts to emulate ecosystem where waste of an organism is being used by another organism, therefore there is no waste in the nature. This system becomes an effort to optimize resources (material and energy) as well as minimize waste. Considerable, in a symbiosis incure material and energy flows among industries. Material and energy in an industry are known as cost carriers, thus flow analysis in this system can be conducted in perspective of material, energy and cost, or called as material flow cost accounting (MFCA) that is an economic and ecological appraisal approach. Previous researches shown that MFCA implementation could be used to evaluate an industry's environmental-related efficiency as well as in planning, business control and decision making. Moreover, the MFCA has been extended to assess environmental performance of SMEs Cluster or industrial symbiosis in SMEs Cluster, even to make preliminary design of an industrial symbiosis base on a major industry. This paper describes the use of MFCA to asses performance of SMEs industrial symbiosis and to improve the performance.

Application of material flow analysis to municipal solid waste in Maputo City, Mozambique.

PubMed

Dos Muchangos, Leticia Sarmento; Tokai, Akihiro; Hanashima, Atsuko

2017-03-01

Understanding waste flows within an urban area is important for identifying the main problems and improvement opportunities for efficient waste management. Assessment tools such as material flow analysis (MFA), an extensively applied method in waste management studies, provide a structured and objective evaluating process to characterize the waste management system best, to identify its shortcomings and to propose suitable strategies. This paper presents the application of MFA to municipal solid waste management (MSWM) in Maputo City, the capital of Mozambique. The results included the identification and quantification of the main input and output flows of the MSWM system in 2007 and 2014, from the generation, material recovery and collection, to final disposal and the unaccounted flow of municipal solid waste (MSW). We estimated that the waste generation increased from 397×10 3  tonnes in 2007 to 437×10 3  tonnes in 2014, whereas the total material recovery was insignificant in both years - 3×10 3 and 7×10 3  tonnes, respectively. As for collection and final disposal, the official collection of waste to the local dumpsite in the inner city increased about threefold, from 76×10 3 to 253×10 6  tonnes. For waste unaccounted for, the estimates indicated a reduction during the study period from 300×10 3 to 158×10 3  tonnes, due to the increase of collection services. The emphasized aspects include the need for practical waste reduction strategies, the opportunity to explore the potential for material recovery, careful consideration regarding the growing trend of illegal dumping and the urgency in phasing-out from the harmful practice of open dumping.

Emergy evaluation of water utilization benefits in water-ecological-economic system based on water cycle process

NASA Astrophysics Data System (ADS)

Guo, X.; Wu, Z.; Lv, C.

2017-12-01

The water utilization benefits are formed by the material flow, energy flow, information flow and value stream in the whole water cycle process, and reflected along with the material circulation of inner system. But most of traditional water utilization benefits evaluation are based on the macro level, only consider the whole material input and output and energy conversion relation, and lack the characterization of water utilization benefits accompanying with water cycle process from the formation mechanism. In addition, most studies are from the perspective of economics, only pay attention to the whole economic output and sewage treatment economic investment, but neglect the ecological function benefits of water cycle, Therefore, from the perspective of internal material circulation in the whole system, taking water cycle process as the process of material circulation and energy flow, the circulation and flow process of water and other ecological environment, social economic elements were described, and the composition of water utilization positive and negative benefits in water-ecological-economic system was explored, and the performance of each benefit was analyzed. On this basis, the emergy calculation method of each benefit was proposed by emergy quantitative analysis technique, which can realize the unified measurement and evaluation of water utilization benefits in water-ecological-economic system. Then, taking Zhengzhou city as an example, the corresponding benefits of different water cycle links were calculated quantitatively by emergy method, and the results showed that the emergy evaluation method of water utilization benefits can unify the ecosystem and the economic system, achieve uniform quantitative analysis, and measure the true value of natural resources and human economic activities comprehensively.

Cost and performance prospects for composite bipolar plates in fuel cells and redox flow batteries

NASA Astrophysics Data System (ADS)

Minke, Christine; Hickmann, Thorsten; dos Santos, Antonio R.; Kunz, Ulrich; Turek, Thomas

2016-02-01

Carbon-polymer-composite bipolar plates (BPP) are suitable for fuel cell and flow battery applications. The advantages of both components are combined in a product with high electrical conductivity and good processability in convenient polymer forming processes. In a comprehensive techno-economic analysis of materials and production processes cost factors are quantified. For the first time a technical cost model for BPP is set up with tight integration of material characterization measurements.

On-chip free-flow magnetophoresis: continuous flow separation of magnetic particles and agglomerates.

PubMed

Pamme, Nicole; Manz, Andreas

2004-12-15

The separation of magnetic microparticles was achieved by on-chip free-flow magnetophoresis. In continuous flow, magnetic particles were deflected from the direction of laminar flow by a perpendicular magnetic field depending on their magnetic susceptibility and size and on the flow rate. Magnetic particles could thus be separated from each other and from nonmagnetic materials. Magnetic and nonmagnetic particles were introduced into a microfluidic separation chamber, and their deflection was studied under the microscope. The magnetic particles were 2.0 and 4.5 microm in diameter with magnetic susceptibilities of 1.12 x 10(-4) and 1.6 x 10(-4) m(3) kg(-1), respectively. The 4.5-microm particles with the larger susceptibility were deflected further from the direction of laminar flow than the 2.0-microm magnetic particles. Nonmagnetic 6-microm polystyrene beads, however, were not deflected at all. Furthermore, agglomerates of magnetic particles were found to be deflected to a larger extent than single magnetic particles. The applied flow rate and the strength and gradient of the applied magnetic field were the key parameters in controlling the deflection. This separation method has a wide applicability since magnetic particles are commonly used in bioanalysis as a solid support material for antigens, antibodies, DNA, and even cells. Free-flow magnetophoretic separations could be hyphenated with other microfluidic devices for reaction and analysis steps to form a micro total analysis system.

High temperature flow-through device for rapid solubilization and analysis

DOEpatents

West, Jason A. A. [Castro Valley, CA; Hukari, Kyle W [San Ramon, CA; Patel, Kamlesh D [Dublin, CA; Peterson, Kenneth A [Albuquerque, NM; Renzi, Ronald F [Tracy, CA

2009-09-22

Devices and methods for thermally lysing of biological material, for example vegetative bacterial cells and bacterial spores, are provided. Hot solution methods for solubilizing bacterial spores are described. Systems for direct analysis are disclosed including thermal lysers coupled to sample preparation stations. Integrated systems capable of performing sample lysis, labeling and protein fingerprint analysis of biological material, for example, vegetative bacterial cells, bacterial spores and viruses are provided.

High temperature flow-through device for rapid solubilization and analysis

DOEpatents

West, Jason A. A.; Hukari, Kyle W.; Patel, Kamlesh D.; Peterson, Kenneth A.; Renzi, Ronald F.

2013-04-23

Devices and methods for thermally lysing of biological material, for example vegetative bacterial cells and bacterial spores, are provided. Hot solution methods for solubilizing bacterial spores are described. Systems for direct analysis are disclosed including thermal lysers coupled to sample preparation stations. Integrated systems capable of performing sample lysis, labeling and protein fingerprint analysis of biological material, for example, vegetative bacterial cells, bacterial spores and viruses are provided.

Thermal and flow analysis of the Fluor Daniel, Inc., Nuclear Material Storage Facility renovation design (initial 30% effort of Title 1)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinke, R.G.; Mueller, C.; Knight, T.D.

1998-03-01

The computational fluid dynamics code CFX4.2 was used to evaluate steady-state thermal-hydraulic conditions in the Fluor Daniel, Inc., Nuclear Material Storage Facility renovation design (initial 30% of Title 1). Thirteen facility cases were evaluated with varying temperature dependence, drywell-array heat-source magnitude and distribution, location of the inlet tower, and no-flow curtains in the drywell-array vault. Four cases of a detailed model of the inlet-tower top fixture were evaluated to show the effect of the canopy-cruciform fixture design on the air pressure and flow distributions.

Finite element flow analysis; Proceedings of the Fourth International Symposium on Finite Element Methods in Flow Problems, Chuo University, Tokyo, Japan, July 26-29, 1982

NASA Astrophysics Data System (ADS)

Kawai, T.

Among the topics discussed are the application of FEM to nonlinear free surface flow, Navier-Stokes shallow water wave equations, incompressible viscous flows and weather prediction, the mathematical analysis and characteristics of FEM, penalty function FEM, convective, viscous, and high Reynolds number FEM analyses, the solution of time-dependent, three-dimensional and incompressible Navier-Stokes equations, turbulent boundary layer flow, FEM modeling of environmental problems over complex terrain, and FEM's application to thermal convection problems and to the flow of polymeric materials in injection molding processes. Also covered are FEMs for compressible flows, including boundary layer flows and transonic flows, hybrid element approaches for wave hydrodynamic loadings, FEM acoustic field analyses, and FEM treatment of free surface flow, shallow water flow, seepage flow, and sediment transport. Boundary element methods and FEM computational technique topics are also discussed. For individual items see A84-25834 to A84-25896

An Analysis of the Effects of Chip-groove Geometry on Machining Performance Using Finite Element Methods

NASA Astrophysics Data System (ADS)

Ee, K. C.; Dillon, O. W.; Jawahir, I. S.

2004-06-01

This paper discusses the influence of major chip-groove parameters of a cutting tool on the chip formation process in orthogonal machining using finite element (FE) methods. In the FE formulation, a thermal elastic-viscoplastic material model is used together with a modified Johnson-Cook material law for the flow stress. The chip back-flow angle and the chip up-curl radius are calculated for a range of cutting conditions by varying the chip-groove parameters. The analysis provides greater understanding of the effectiveness of chip-groove configurations and points a way to correlate cutting conditions with tool-wear when machining with a grooved cutting tool.

Crashworthiness analysis using advanced material models in DYNA3D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Logan, R.W.; Burger, M.J.; McMichael, L.D.

1993-10-22

As part of an electric vehicle consortium, LLNL and Kaiser Aluminum are conducting experimental and numerical studies on crashworthy aluminum spaceframe designs. They have jointly explored the effect of heat treat on crush behavior and duplicated the experimental behavior with finite-element simulations. The major technical contributions to the state of the art in numerical simulation arise from the development and use of advanced material model descriptions for LLNL`s DYNA3D code. Constitutive model enhancements in both flow and failure have been employed for conventional materials such as low-carbon steels, and also for lighter weight materials such as aluminum and fiber compositesmore » being considered for future vehicles. The constitutive model enhancements are developed as extensions from LLNL`s work in anisotropic flow and multiaxial failure modeling. Analysis quality as a function of level of simplification of material behavior and mesh is explored, as well as the penalty in computation cost that must be paid for using more complex models and meshes. The lightweight material modeling technology is being used at the vehicle component level to explore the safety implications of small neighborhood electric vehicles manufactured almost exclusively from these materials.« less

Reutilisation-extended material flows and circular economy in China.

PubMed

Li, Nan; Zhang, Tianzhu; Liang, Sai

2013-06-01

Circular economy (CE), with its basic principle of Reduce, Reuse, and Recycle, has been determined as the key strategy for the national development plan by the Chinese government. Given the economy-wide material flow analysis (EW-MFA) that leaves the inner flow of resource reutilisation unidentified, the reutilisation-extended EW-MFA is first introduced to evaluate and analyse the material input, solid waste generation, and reutilisation simultaneously. The total amount of comprehensive reutilisation (CR) is divided into three sub-flows, namely, reutilisation, recycle, and reuse. Thus, this model is used to investigate the resource CR in China from 2000 to 2010. China's total amount of CR and its sub-flows, as well as the CR rate, remain to have a general upward trend. By the year 2010, about 60% of the overall solid waste generation had already been reutilised, and more than 20% of the total resource requirement was reutilised resource. Moreover, the growth patterns of the CR sub flows show different characteristics. Interpretations of resource reutilisation-related laws and regulations of CE and the corresponding policy suggestions are proposed based on the results. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fundamental Studies of Strength Physics--Methodology of Longevity Prediction of Materials under Arbitrary Thermally and Forced Effects

ERIC Educational Resources Information Center

Petrov, Mark G.

2016-01-01

Thermally activated analysis of experimental data allows considering about the structure features of each material. By modelling the structural heterogeneity of materials by means of rheological models, general and local plastic flows in metals and alloys can be described over. Based on physical fundamentals of failure and deformation of materials…

Development of a methodology for electronic waste estimation: A material flow analysis-based SYE-Waste Model.

PubMed

Yedla, Sudhakar

2016-01-01

Improved living standards and the share of services sector to the economy in Asia, and the use of electronic equipment is on the rise and results in increased electronic waste generation. A peculiarity of electronic waste is that it has a 'significant' value even after its life time, and to add complication, even after its extended life in its 'dump' stage. Thus, in Indian situations, after its life time is over, the e-material changes hands more than once and finally ends up either in the hands of informal recyclers or in the store rooms of urban dwellings. This character makes it extremely difficult to estimate electronic waste generation. The present study attempts to develop a functional model based on a material flow analysis approach by considering all possible end uses of the material, its transformed goods finally arriving at disposal. It considers various degrees of uses derived of the e-goods regarding their primary use (life time), secondary use (first degree extension of life), third-hand use (second degree extension of life), donation, retention at the respective places (without discarding), fraction shifted to scrap vendor, and the components reaching the final dump site from various end points of use. This 'generic functional model' named SYE-Waste Model, developed based on a material flow analysis approach, can be used to derive 'obsolescence factors' for various degrees of usage of e-goods and also to make a comprehensive estimation of electronic waste in any city/country. © The Author(s) 2015.

Analysis of the cooling of continuous flow helium cryostats

NASA Astrophysics Data System (ADS)

Pust, L.

A mathematical model of the cooling of a continuous-flow cryostat which takes into account real values of the specific and latent heat of the cryogenic fluid and of the specific heat of the cryostat material is presented. The amount of liquid in the cooling fluid and four parasitic heat flows, caused by radiation and heat conduction in the construction materials and in the rest gas in the vacuum insulation, are also taken into account. The influence of different model parameters on performance, particularly in the non-stationary regime, is demonstrated by means of numerical solutions of the modelling equations. A quantitative criterion which assesses the properties of the planned cryostat, is formulated. The theoretical conclusions are compared with measurements performed on a continuous flow helium cryostat.

A direct comparison of the performance of ground, beaded and silica-grafted MIPs in HPLC and turbulent flow chromatography applications.

PubMed

Fairhurst, Robert E; Chassaing, Christophe; Venn, Richard F; Mayes, Andrew G

2004-12-15

Spherical molecularly imprinted polymers (MIPs) specific to the beta-blocker propranolol have been synthesised using two different approaches and compared to traditional ground monolithic MIPs in HPLC and TFC applications. TFC is a LC technique used for rapid extraction of compounds directly from complex matrices. It can be easily coupled to HPLC and MS for automation of an extraction/analysis procedure. Spherical MIP beads were produced using a suspension polymerisation technique and silica/MIP composite beads by grafting MIP to spherical silica particles using a surface-bound initiator species. Synthesis of both beaded and silica-grafted MIPs was more practical than using the traditional grinding method and yields of spherical particles of the required size between 80 and 100% were routinely achieved. Under HPLC conditions, beaded and ground MIP materials showed a degree of chiral separation for all of the nine beta-blockers tested. The beaded MIP, however, showed much better flow properties and peak shape than the ground material. Silica-grafted MIP showed some separation in five of the drugs and a large improvement in peak shape and analysis times compared with both ground and beaded MIPs. The materials prepared were also used in extraction columns for Turbulent Flow Chromatography (TFC). Although no imprinting effect was observed under typical TFC conditions, beaded polymer materials showed promise for use as TFC extraction columns due to the good flow properties and clean extracts obtained.

Resource recovery from residual household waste: An application of exergy flow analysis and exergetic life cycle assessment.

PubMed

Laner, David; Rechberger, Helmut; De Soete, Wouter; De Meester, Steven; Astrup, Thomas F

2015-12-01

Exergy is based on the Second Law of thermodynamics and can be used to express physical and chemical potential and provides a unified measure for resource accounting. In this study, exergy analysis was applied to four residual household waste management scenarios with focus on the achieved resource recovery efficiencies. The calculated exergy efficiencies were used to compare the scenarios and to evaluate the applicability of exergy-based measures for expressing resource quality and for optimizing resource recovery. Exergy efficiencies were determined based on two approaches: (i) exergy flow analysis of the waste treatment system under investigation and (ii) exergetic life cycle assessment (LCA) using the Cumulative Exergy Extraction from the Natural Environment (CEENE) as a method for resource accounting. Scenario efficiencies of around 17-27% were found based on the exergy flow analysis (higher efficiencies were associated with high levels of material recycling), while the scenario efficiencies based on the exergetic LCA lay in a narrow range around 14%. Metal recovery was beneficial in both types of analyses, but had more influence on the overall efficiency in the exergetic LCA approach, as avoided burdens associated with primary metal production were much more important than the exergy content of the recovered metals. On the other hand, plastic recovery was highly beneficial in the exergy flow analysis, but rather insignificant in exergetic LCA. The two approaches thereby offered different quantitative results as well as conclusions regarding material recovery. With respect to resource quality, the main challenge for the exergy flow analysis is the use of exergy content and exergy losses as a proxy for resource quality and resource losses, as exergy content is not per se correlated with the functionality of a material. In addition, the definition of appropriate waste system boundaries is critical for the exergy efficiencies derived from the flow analysis, as it is constrained by limited information available about the composition of flows in the system as well as about secondary production processes and their interaction with primary or traditional production chains. In the exergetic LCA, resource quality could be reflected by the savings achieved by product substitution and the consideration of the waste's upstream burden allowed for an evaluation of the waste's resource potential. For a comprehensive assessment of resource efficiency in waste LCA, the sensitivity of accounting for product substitution should be carefully analyzed and cumulative exergy consumption measures should be complimented by other impact categories. Copyright © 2015 Elsevier Ltd. All rights reserved.

Operational considerations for laminar flow aircraft

NASA Technical Reports Server (NTRS)

Maddalon, Dal V.; Wagner, Richard D.

1986-01-01

Considerable progress has been made in the development of laminar flow technology for commercial transports during the NASA Aircraft Energy Efficiency (ACEE) laminar flow program. Practical, operational laminar flow control (LFC) systems have been designed, fabricated, and are undergoing flight testing. New materials, fabrication methods, analysis techniques, and design concepts were developed and show much promise. The laminar flow control systems now being flight tested on the NASA Jetstar aircraft are complemented by natural laminar flow flight tests to be accomplished with the F-14 variable-sweep transition flight experiment. An overview of some operational aspects of this exciting program is given.

Fatigue response of perforated titanium for application in laminar flow control

NASA Technical Reports Server (NTRS)

Johnson, W. Steven; Miller, Jennifer L.; Newman, Jr., James

1996-01-01

The room temperature tensile and fatigue response of non-perforated and perforated titanium for laminar flow control application was investigated both experimentally and analytically. Results showed that multiple perforations did not affect the tensile response, but did reduce the fatigue life. A two dimensional finite element stress analysis was used to determine that the stress fields from adjacent perforations did not influence one another. The stress fields around the holes did not overlap one another, allowing the materials to be modeled as a plate with a center hole. Fatigue life was predicted using an equivalent MW flow size approach to relate the experimental results to microstructural features of the titanium. Predictions using flaw sizes ranging from 1 to 15 microns correlated within a factor of 2 with the experimental results by using a flow stress of 260 MPa. By using two different flow stresses in the crack closure model and correcting for plasticity, the experimental results were bounded by the predictions for high applied stresses. Further analysis of the complex geometry of the perforations and the local material chemistry is needed to further understand the fatigue behavior of the perforated titanium.

Thermohydrodynamic Analysis of Cryogenic Liquid Turbulent Flow Fluid Film Bearings

NASA Technical Reports Server (NTRS)

SanAndres, Luis

1996-01-01

Computational programs developed for the thermal analysis of tilting and flexure-pad hybrid bearings, and the unsteady flow and transient response of a point mass rotor supported on fluid film bearings are described. The motion of a cryogenic liquid on the thin film annular region of a fluid film bearing is described by a set of mass and momentum conservation, and energy transport equations for the turbulent bulk-flow velocities and pressure, and accompanied by thermophysical state equations for evaluation of the fluid material properties. Zeroth-order equations describe the fluid flow field for a journal static equilibrium position, while first-order (linear) equations govern the fluid flow for small amplitude-journal center translational motions. Solution to the zeroth-order flow field equations provides the bearing flow rate, load capacity, drag torque and temperature rise. Solution to the first-order equations determines the rotordynamic force coefficients due to journal radial motions.

Orbiter thermal pressure drop characteristics for shuttle orbiter thermal protection system components: High density tile, low density tile, densified low density tile, and strain isolation pad

NASA Technical Reports Server (NTRS)

Lawing, P. L.; Nystrom, D. M.

1980-01-01

Pressure drop tests were conducted on available samples of low and high density tile, densified low density tile, and strain isolation pads. The results are presented in terms of pressure drop, material thickness and volume flow rate. Although the test apparatus was only capable of a small part of the range of conditions to be encountered in a Shuttle Orbiter flight, the data serve to determine the type of flow characteristics to be expected for each material type tested; the measured quantities also should serve as input for initial venting and flow through analysis.

An Integrated Tool for the Coupled Thermal and Mechanical Analysis of Pyrolyzing Heatshield Materials

NASA Technical Reports Server (NTRS)

Pronchick, Stephen W.

1998-01-01

Materials that pyrolyze at elevated temperature have been commonly used as thermal protection materials in hypersonic flight, and advanced pyrolyzing materials for this purpose continue to be developed. Because of the large temperature gradients that can arise in thermal protection materials, significant thermal stresses can develop. Advanced applications of pyrolytic materials are calling for more complex heatshield configurations, making accurate thermal stress analysis more important, and more challenging. For non-pyrolyzing materials, many finite element codes are available and capable of performing coupled thermal-mechanical analyses. These codes do not, however, have a built-in capability to perform analyses that include pyrolysis effects. When a pyrolyzing material is heated, one or more components of the original virgin material pyrolyze and create a gas. This gas flows away from the pyrolysis zone to the surface, resulting in a reduction in surface heating. A porous residue, referred to as char, remains in place of the virgin material. While the processes involved can be complex, it has been found that a simple physical model in which virgin material reacts to form char and pyrolysis gas, will yield satisfactory analytical results. Specifically, the effects that must be modeled include: (1) Variation of thermal properties (density, specific heat, thermal conductivity) as the material composition changes; (2) Energy released or absorbed by the pyrolysis reactions; (3) Energy convected by the flow of pyrolysis gas from the interior to the surface; (4) The reduction in surface heating due to surface blowing; and (5) Chemical and mass diffusion effects at the surface between the pyrolysis gas and edge gas Computational tools for the one-dimensional thermal analysis these materials exist and have proven to be reliable design tools. The objective of the present work is to extend the analysis capabilities of pyrolyzing materials to axisymmetric configurations, and to couple thermal and mechanical analyses so that thermal stresses may be efficiently and accurately calculated.

Negotiating energy dynamics through embodied action in a materially structured environment

NASA Astrophysics Data System (ADS)

Scherr, Rachel E.; Close, Hunter G.; Close, Eleanor W.; Flood, Virginia J.; McKagan, Sarah B.; Robertson, Amy D.; Seeley, Lane; Wittmann, Michael C.; Vokos, Stamatis

2013-12-01

We provide evidence that a learning activity called Energy Theater engages learners with key conceptual issues in the learning of energy, including disambiguating matter flow and energy flow and theorizing mechanisms for energy transformation. A participationist theory of learning, in which learning is indicated by changes in speech and behavior, supports ethnographic analysis of learners’ embodied interactions with each other and the material setting. We conduct detailed analysis to build plausible causal links between specific features of Energy Theater and the conceptual engagement that we observe. Disambiguation of matter and energy appears to be promoted especially by the material structure of the Energy Theater environment, in which energy is represented by participants, while objects are represented by areas demarcated by loops of rope. Theorizing mechanisms of energy transformation is promoted especially by Energy Theater’s embodied action, which necessitates modeling the time ordering of energy transformations.

Two-Dimensional Finite Element Ablative Thermal Response Analysis of an Arcjet Stagnation Test

NASA Technical Reports Server (NTRS)

Dec, John A.; Laub, Bernard; Braun, Robert D.

2011-01-01

The finite element ablation and thermal response (FEAtR, hence forth called FEAR) design and analysis program simulates the one, two, or three-dimensional ablation, internal heat conduction, thermal decomposition, and pyrolysis gas flow of thermal protection system materials. As part of a code validation study, two-dimensional axisymmetric results from FEAR are compared to thermal response data obtained from an arc-jet stagnation test in this paper. The results from FEAR are also compared to the two-dimensional axisymmetric computations from the two-dimensional implicit thermal response and ablation program under the same arcjet conditions. The ablating material being used in this arcjet test is phenolic impregnated carbon ablator with an LI-2200 insulator as backup material. The test is performed at the NASA, Ames Research Center Interaction Heating Facility. Spatially distributed computational fluid dynamics solutions for the flow field around the test article are used for the surface boundary conditions.

Study of flow stress and spall strength of additively manufactured Ti-6-4 alloy

NASA Astrophysics Data System (ADS)

Cohen, Amitay; Paris, Vitaly; Yosef-Hai, Arnon; Gudinetsky, Eli; Tiferet, Eitan

2017-06-01

The use of additive manufacturing (AM) by Electron Beam Melting (EBM) or Selective Laser Melting (SLM) has extensively grown in the past few years. A major goal in AM is to manufacture materials with mechanical properties at least as good as traditionally manufactured materials. In this work we present results of planar impact tests and Split Hopkinson Pressure Bar tests (SHPB) on Ti-6-4 manufactured by EBM and SLM processes. Results of planar impact tests on SLM samples display slightly higher spall strength compared to EBM while the stress at Hugoniot elastic limit (HEL) is practically the same. Stress strain curves based on SHPB measurements at two different strain rates present similar plastic flow stresses for SLM and EBM processed Ti-6-4 alloy, while the flow stress is about 20% higher than reported for commercial reference material. The strain to failure of both materials shows considerable strain rate sensitivity. The results of post-mortem analysis of spall fracture will also be presented.

Using U.S. Geological Survey data in material flow analysis: An introduction

USGS Publications Warehouse

Sibley, S.F.

2009-01-01

A few sources of basic data on worldwide raw materials production and consumption exist that are independently developed and freely available to the public. This column is an introduction to the types of information available from the U.S. Geological Survey (USGS), and explains how the data are assembled. The kind of information prepared by the USGS is essential to U.S. materials flow studies because the data make it possible to conduct these studies within a global context. The data include primary and secondary (scrap) production, consumption and stocks (mostly limited to the United States unless calculated), trade (not readily available for all countries), and prices for more than 80 mineral commodities. Materials flow studies by USGS specialists using these data are continuing (http://minerals.usgs.gov/minerals/mflow/). Figure 1 shows from where the data are collected and where they are used. Minerals information was downloaded by users 5.8 million times from USGS minerals information Web pages in 2008.

A note on flow reversal in a wavy channel filled with anisotropic porous material

NASA Astrophysics Data System (ADS)

Karmakar, Timir; Raja Sekhar, G. P.

2017-07-01

Viscous flow through a symmetric wavy channel filled with anisotropic porous material is investigated analytically. Flow inside the porous bed is assumed to be governed by the anisotropic Brinkman equation. It is assumed that the ratio of the channel width to the wavelength is small (i.e. δ2≪1). The problem is solved up to O(δ2) assuming that δ2λ2≪1, where λ is the anisotropic ratio. The key purpose of this paper is to study the effect of anisotropic permeability on flow near the crests of the wavy channel which causes flow reversal. We present a detailed analysis of the flow reversal at the crests. The ratio of the permeabilities (anisotropic ratio) is responsible for the flow separation near the crests of the wall where viscous forces are effective. For a flow configuration (say, low amplitude parameter) in which there is no separation if the porous media is isotropic, introducing anisotropy causes flow separation. On the other hand, interestingly, flow separation occurs even in the case of isotropic porous medium if the amplitude parameter a is large.

Flows of engineered nanomaterials through the recycling process in Switzerland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caballero-Guzman, Alejandro; Sun, Tianyin; Nowack, Bernd, E-mail: nowack@empa.ch

Highlights: • Recycling is one of the likely end-of-life fates of nanoproducts. • We assessed the material flows of four nanomaterials in the Swiss recycling system. • After recycling, most nanomaterials will flow to landfills or incineration plants. • Recycled construction waste, plastics and textiles may contain nanomaterials. - Abstract: The use of engineered nanomaterials (ENMs) in diverse applications has increased during the last years and this will likely continue in the near future. As the number of applications increase, more and more waste with nanomaterials will be generated. A portion of this waste will enter the recycling system, formore » example, in electronic products, textiles and construction materials. The fate of these materials during and after the waste management and recycling operations is poorly understood. The aim of this work is to model the flows of nano-TiO{sub 2}, nano-ZnO, nano-Ag and CNT in the recycling system in Switzerland. The basis for this study is published information on the ENMs flows on the Swiss system. We developed a method to assess their flow after recycling. To incorporate the uncertainties inherent to the limited information available, we applied a probabilistic material flow analysis approach. The results show that the recycling processes does not result in significant further propagation of nanomaterials into new products. Instead, the largest proportion will flow as waste that can subsequently be properly handled in incineration plants or landfills. Smaller fractions of ENMs will be eliminated or end up in materials that are sent abroad to undergo further recovery processes. Only a reduced amount of ENMs will flow back to the productive process of the economy in a limited number of sectors. Overall, the results suggest that risk assessment during recycling should focus on occupational exposure, release of ENMs in landfills and incineration plants, and toxicity assessment in a small number of recycled inputs.« less

Hydrodynamic resistance parameters for ErPr rare-earth regenerator material under steady and periodic flow conditions

NASA Astrophysics Data System (ADS)

Pathak, M. G.; Helvensteijn, B. P.; Patel, V. C.; Ghiaasiaan, S. M.; Mulcahey, T. I.; Kashani, A.; Feller, J. R.

2014-01-01

The regenerator, typically a microporous structure that is subject to periodic flow of a cryogenic fluid, is a critical component of pulse tube or Stirling cryocoolers, which are widely used for high-demand aerospace and defense applications. In this investigation, experiments were conducted in which steady and oscillatory flows of helium were imposed on ErPr rare-Earth regenerator filler material and mass flow and pressure drop data were recorded under ambient temperature conditions. A computational fluid dynamics (CFD)-assisted method was applied for the analysis and interpretation of the experimental data. The permeability and inertial coefficients that lead to agreement between the experimental data and computational simulations were iteratively obtained. The Darcy permeability and Forchheimer inertial coefficients were obtained and were found to be functions of the system charge pressure, operating frequency, and compressor piston stroke within the studied range of interest. The results also exhibit that the periodic flow hydrodynamic resistance parameters are in general different than steady flow parameters.

Damping insert materials for settling chambers of supersonic wind tunnels

NASA Astrophysics Data System (ADS)

Wu, Jie; Radespiel, Rolf

2017-03-01

This study describes the application of a novel damping insert material for reducing the flow fluctuations in a tandem nozzle supersonic wind tunnel. This new damping material is composed of multi-layer stainless steel wired meshes. The influences of the multi-layer mesh, such as the quantity of the mesh layer and the installed location in the settling chamber, to the freestream quality have been investigated. A Pitot probe instrumented with a Kulite pressure sensor and a hot-wire probe are employed to monitor the flow fluctuation in the test section of the wind tunnel. Thereafter, a combined modal analysis is applied for the disturbance qualification. Additionally, the transient Mach number in the test section is measured. The disturbance qualification indicates that the multi-layer mesh performs well in providing reduction of vorticity reduction and acoustic fluctuations. Comparable flow quality of the freestream was also obtained using a combination of flexible damping materials. However, the life-span of the new damping materials is much longer. The time transient of the Mach number measured in the test section indicates that the mean flow is rather constant over run time. Furthermore, the time-averaged pressure along the settling chamber is recorded and it shows the distribution of pressure drop by settling chamber inserts.

Using SERC for creating and publishing student generated hydrology instruction materials

NASA Astrophysics Data System (ADS)

Merwade, V.; Rajib, A.; Ruddell, B.; Fox, S.

2016-12-01

Hydrology instruction typically involves teaching of the hydrologic cycle and the processes associated with it such as precipitation, evapotranspiration, infiltration, runoff generation and hydrograph analysis. With the availability of observed and remotely sensed data in public domain, there is an opportunity to incorporate place-based learning in hydrology classrooms. However, it is not always easy and possible for an instructor to complement an existing hydrology course with new material that requires both time and technical expertise, which the instructor may not have. The work presented here describes an effort where students created the data and modeling driven instruction materials as part of their class assignment for a hydrology course at Purdue University. Students in the class were divided into groups, and each group was assigned a topic such as precipitation, evapotranspiration, streamflow, flow duration curve and flood frequency analysis. Each of the student groups was then instructed to produce an instruction material showing ways to extract/process relevant data and perform some analysis for an area with specific land use characteristic. The student contributions were then organized into learning units such that someone can do a flow duration curve analysis or flood frequency analysis and see how it changes for rural area versus urban area. Science Education Resource Center (SERC) is used as a platform to publish and share these instruction materials so it can be used as-is or through modification by any instructor or student in relevant coursework anywhere in the world.

3D-CFD analysis of diffusion and emission of VOCs in a FLEC cavity.

PubMed

Zhu, Q; Kato, S; Murakami, S; Ito, K

2007-06-01

This study is performed as a part of research that examines the emission and diffusion characteristics of volatile organic compounds (VOCs) from indoor building materials. In this paper, the flow field and the emission field of VOCs from the surface of building materials in a Field and Laboratory Emission Cell (FLEC) cavity are examined by 3D Computational Fluid Dynamics (CFD) analysis. The flow field within the FLEC cavity is laminar. With a total flow of 250 ml/min, the air velocity near the test material surface ranges from 0.1 to 4.5 cm/s. Three types of emission from building materials are studied here: (i) emission phenomena controlled by internal diffusion, (ii) emission phenomena controlled by external diffusion, and (iii) emission phenomena controlled by mixed diffusion (internal + external diffusion). In the case of internal diffusion material, with respect to the concentration distribution in the cavity, the local VOC emission rate becomes uniform and the FLEC works well. However, in the case of evaporation type (external diffusion) material, or mixed type materials (internal + external diffusion) when the resistance to transporting VOCs in the material is small, the FLEC is not suitable for emission testing because of the thin FLEC cavity. In this case, the mean emission rate is restricted to a small value, since the VOC concentration in the cavity rises to the same value as the surface concentration through molecular diffusion within the thin cavity, and the concentration gradient normal to the surface becomes small. The diffusion field and emission rate depend on the cavity concentration and on the Loading Factor. That is, when the testing material surface in the cavity is partially sealed to decrease the Loading Factor, the emission rate become higher with the decrease in the exposed area of the testing material. The flow field and diffusion field within the FLEC cavity are investigated by CFD method. After presenting a summary of the velocity distributed over the surface of test material and the emission properties of different type materials in FLEC, the paper pointed out that there is a bias in the airflow inside the FLEC cavity but do not influence the result of test emission rate, and the FLEC method is unsuitable for evaporation type materials in which the mass transfer of the surface controls the emission rate.

Industrial Technology Modernization Program. Project 80. Increase Efficiency of Card Test/Device Test Areas by the Usage of Improved Material Handling Systems. Revision 1. Phase 2

DTIC Science & Technology

1988-03-01

INDUSTRY ANALYSIS/FINDINGS 132 12 EQUIPMENT/MACHINERY ALTERNATIVES 134 13 MIS REQUIREMENTS/IMPROVEMENTS 135 14 COST BENEFIT ANALYSIS AND PROCEDURE 137 15...SOFTWARE DIAGRAM 14.0-1 COST BENEFIT ANALYSIS METHODOLOGY 138 14.3-1 PROJECT 80 EXPENDITURE SCHEDULE 141 14.4-1 PROJECT 80 CASH FLOWS 142 15.1-1 PROJECT 80...testing, streamlining work flow, and installation of ergonomically designed work cell/work centers. The benefits associated with the implementation of ITM

MANTLE: A finite element program for the thermal-mechanical analysis of mantle convection. A user's manual with examples

NASA Technical Reports Server (NTRS)

Thompson, E.

1979-01-01

A finite element computer code for the analysis of mantle convection is described. The coupled equations for creeping viscous flow and heat transfer can be solved for either a transient analysis or steady-state analysis. For transient analyses, either a control volume or a control mass approach can be used. Non-Newtonian fluids with viscosities which have thermal and spacial dependencies can be easily incorporated. All material parameters may be written as function statements by the user or simply specified as constants. A wide range of boundary conditions, both for the thermal analysis and the viscous flow analysis can be specified. For steady-state analyses, elastic strain rates can be included. Although this manual was specifically written for users interested in mantle convection, the code is equally well suited for analysis in a number of other areas including metal forming, glacial flows, and creep of rock and soil.

Material flow analysis of NdFeB magnets for Denmark: a comprehensive waste flow sampling and analysis approach.

PubMed

Habib, Komal; Schibye, Peter Klausen; Vestbø, Andreas Peter; Dall, Ole; Wenzel, Henrik

2014-10-21

Neodymium-iron-boron (NdFeB) magnets have become highly desirable for modern hi-tech applications. These magnets, in general, contain two key rare earth elements (REEs), i.e., neodymium (Nd) and dysprosium (Dy), which are responsible for the very high strength of these magnets, allowing for considerable size and weight reduction in modern applications. This study aims to explore the current and future potential of a secondary supply of neodymium and dysprosium from recycling of NdFeB magnets. For this purpose, material flow analysis (MFA) has been carried out to perform the detailed mapping of stocks and flows of NdFeB magnets in Denmark. A novel element of this study is the value added to the traditionally practiced MFAs at national and/or global levels by complementing them with a comprehensive sampling and elemental analysis of NdFeB magnets, taken out from a sample of 157 different products representing 18 various product types. The results show that the current amount of neodymium and dysprosium in NdFeB magnets present in the Danish waste stream is only 3 and 0.2 Mg, respectively. However, this number is estimated to increase to 175 Mg of neodymium and 11.4 Mg of dysprosium by 2035. Nevertheless, efficient recovery of these elements from a very diverse electronic waste stream remains a logistic and economic challenge.

Melt-Flow Behaviours of Thermoplastic Materials under Fire Conditions: Recent Experimental Studies and Some Theoretical Approaches

PubMed Central

Joseph, Paul; Tretsiakova-McNally, Svetlana

2015-01-01

Polymeric materials often exhibit complex combustion behaviours encompassing several stages and involving solid phase, gas phase and interphase. A wide range of qualitative, semi-quantitative and quantitative testing techniques are currently available, both at the laboratory scale and for commercial purposes, for evaluating the decomposition and combustion behaviours of polymeric materials. They include, but are not limited to, techniques such as: thermo-gravimetric analysis (TGA), oxygen bomb calorimetry, limiting oxygen index measurements (LOI), Underwriters Laboratory 94 (UL-94) tests, cone calorimetry, etc. However, none of the above mentioned techniques are capable of quantitatively deciphering the underpinning physiochemical processes leading to the melt flow behaviour of thermoplastics. Melt-flow of polymeric materials can constitute a serious secondary hazard in fire scenarios, for example, if they are present as component parts of a ceiling in an enclosure. In recent years, more quantitative attempts to measure the mass loss and melt-drip behaviour of some commercially important chain- and step-growth polymers have been accomplished. The present article focuses, primarily, on the experimental and some theoretical aspects of melt-flow behaviours of thermoplastics under heat/fire conditions. PMID:28793746

Melt-Flow Behaviours of Thermoplastic Materials under Fire Conditions: Recent Experimental Studies and Some Theoretical Approaches.

PubMed

Joseph, Paul; Tretsiakova-McNally, Svetlana

2015-12-15

Polymeric materials often exhibit complex combustion behaviours encompassing several stages and involving solid phase, gas phase and interphase. A wide range of qualitative, semi-quantitative and quantitative testing techniques are currently available, both at the laboratory scale and for commercial purposes, for evaluating the decomposition and combustion behaviours of polymeric materials. They include, but are not limited to, techniques such as: thermo-gravimetric analysis (TGA), oxygen bomb calorimetry, limiting oxygen index measurements (LOI), Underwriters Laboratory 94 (UL-94) tests, cone calorimetry, etc. However, none of the above mentioned techniques are capable of quantitatively deciphering the underpinning physiochemical processes leading to the melt flow behaviour of thermoplastics. Melt-flow of polymeric materials can constitute a serious secondary hazard in fire scenarios, for example, if they are present as component parts of a ceiling in an enclosure. In recent years, more quantitative attempts to measure the mass loss and melt-drip behaviour of some commercially important chain- and step-growth polymers have been accomplished. The present article focuses, primarily, on the experimental and some theoretical aspects of melt-flow behaviours of thermoplastics under heat/fire conditions.

Life Science Research Facility materials management requirements and concepts

NASA Technical Reports Server (NTRS)

Johnson, Catherine C.

1986-01-01

The Advanced Programs Office at NASA Ames Research Center has defined hypothetical experiments for a 90-day mission on Space Station to allow analysis of the materials necessary to conduct the experiments and to assess the impact on waste processing of recyclable materials and storage requirements of samples to be returned to earth for analysis as well as of nonrecyclable materials. The materials include the specimens themselves, the food, water, and gases necessary to maintain them, the expendables necessary to conduct the experiments, and the metabolic products of the specimens. This study defines the volumes, flow rates, and states of these materials. Process concepts for materials handling will include a cage cleaner, trash compactor, biological stabilizer, and various recycling devices.

Analysis of Active Lava Flows on Kilauea Volcano, Hawaii, Using SIR-C Radar Correlation Measurements

NASA Technical Reports Server (NTRS)

Zebker, H. A.; Rosen, P.; Hensley, S.; Mouginis-Mark, P. J.

1995-01-01

Precise eruption rates of active pahoehoe lava flows on Kilauea volcano, Hawaii, have been determined using spaceborne radar data acquired by the Space Shuttle Imaging Radar-C (SIR-C). Measurement of the rate of lava flow advance, and the determination of the volume of new material erupted in a given period of time, are among the most important observations that can be made when studying a volcano.

Consumables and wastes estimations for the First Lunar Outpost

NASA Technical Reports Server (NTRS)

Theis, Ronald L. A.; Ballin, Mark G.; Evert, Martha F.

1992-01-01

The First Lunar Outpost mission is a design reference mission for the first human return to the moon. This paper describes a set of consumables and waste material estimations made on the basis of the First Lunar Outpost mission scenario developed by the NASA Exploration Programs Office. The study includes the definition of a functional interface framework and a top-level set of consumables and waste materials to be evaluated, the compilation of mass flow information from mission developers supplemented with information from the literature, and the analysis of the resulting mass flow information to gain insight about the possibility of material flow integration between the moon outpost elements. The results of the study of the details of the piloted mission and the habitat are used to identify areas where integration of consumables and wastes across different mission elements could provide possible launch mass savings.

Material Stock Demographics: Cars in Great Britain.

PubMed

Cabrera Serrenho, André; Allwood, Julian M

2016-03-15

Recent literature on material flow analysis has been focused on quantitative characterization of past material flows. Fewer analyses exist on past and prospective quantification of stocks of materials in-use. Some of these analyses explore the composition of products' stocks, but a focus on the characterization of material stocks and its relation with service delivery is often neglected. We propose the use of the methods of human demography to characterize material stocks, defined herein as stock demographics, exploring the insights that this approach could provide for the sustainable management of materials. We exemplify an application of stock demographics by characterizing the composition and service delivery of iron, steel, and aluminum stocks of cars in Great Britain, 2002-2012. The results show that in this period the stock has become heavier, it is traveling less, and it is idle for more time. The visualization of material stocks' dynamics demonstrates the pace of product replacement as a function of its usefulness and enables the formulation of policy interventions and the exploration of future trends.

Non Destructive Analysis of Fsw Welds using Ultrasonic Signal Analysis

NASA Astrophysics Data System (ADS)

Pavan Kumar, T.; Prabhakar Reddy, P.

2017-08-01

Friction Stir Welding is an evolving metal joining technique and is mostly used in joining materials which cannot be easily joined by other available welding techniques. It is a technique which can be used for welding dissimilar materials also. The strength of the weld joint is determined by the way in which these material are mixing with each other, since we are not using any filler material for the welding process the intermixing has a significant importance. The complication with the friction stir welding process is that there are many process parameters which effect this intermixing process such as tool geometry, rotating speed of the tool, transverse speed etc., In this study an attempt is made to compare the material flow and weld quality of various weldments by changing the parameters. Ultrasonic signal Analysis is used to characterize the microstructure of the weldments. use of ultrasonic waves is a non destructive, accurate and fast way of characterization of microstructure. In this method the relationship between the ultrasonic measured parameters and microstructures are evaluated using background echo and backscattered signal process techniques. The ultrasonic velocity and attenuation measurements are dependent on the elastic modulus and any change in the microstructure is reflected in the ultrasonic velocity. An insight into material flow is essential to determine the quality of the weld. Hence an attempt is made in this study to know the relationship between tool geometry and the pattern of material flow and resulting weld quality the experiments are conducted to weld dissimilar aluminum alloys and the weldments are characterized using and ultra Sonic signal processing. Characterization is also done using Scanning Electron Microscopy. It is observed that there is a good correlation between the ultrasonic signal processing results and Scanning Electron Microscopy on the observed precipitates. Tensile tests and hardness tests are conducted on the weldments and compared for determining the weld quality.

Splash flow from a metal plate hit by an electron beam pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia, M., LLNL

1997-09-01

When a pulsed electron beam hits a metal plate with sufficient energy a volume of the metal becomes hot fluid that subsequently sprays out of the plate. A second pulse of electrons traveling toward the plate would scatter and degrade before impacting the solid plate because of its encounter with the diffuse material of the initial splash. People designing electron beam machines for use as pulsed radiation sources wish to eliminate the interaction between the electrons and the splash because they want sharp radiation pulses emitted from the solid plate. This report presents a compressible fluid model of this splashmore » flow and compares specific cases with experiments and comprehensive calculations performed by B. DeVolder and others at the Los Alamos National Laboratory, see reference (1). My aim was to develop as simple a theory as possible to calculate the speed and density of the splash flow. I have used both simplifying assumptions and mathematical approximations to develop convenient formulas. As I wished to make a clear and interesting presentation of this work to a diverse audience that includes people outside the specialty of fluid dynamics, some of my descriptions may seem wordier than necessary. The plan of the report is as follows. In the section called ``energy deposition`` I describe how an electron beam deposits energy in a solid plate, converting some of the material into a hot fluid. The initial temperature of this fluid is the key parameter in determining the nature of the subsequent flow; an explicit formula is shown. Flow occurs in two regions: along a streamtube within the metal plate and as an expanding plume outside the metal plate. Flow within the plate is described in the section called ``isentropic flow.`` This flow occurs as expansion waves move at the speed of sound through the streamtube. The analysis of this flow provides a formula for the mass flow over time from the plate into the external splash. The section called ``centered expansion`` elaborates on the nature of certain approximations I have made in treating the wave phenomena in both the streamtube and splash flows. The section called ``splash flow`` presents a formula to describe the material density as a function of space and time outside the plate. This formula depends on the time- dependent material density at the plate, which was found during the streamtube analysis. The section called ``examples`` shows the results of specific calculations and a comparison to computational and experimental results described in reference (1). The final section, ``possible future work,`` poses new questions.« less

Quantifying Thin Mat Floating Marsh Strength and Interaction with Hydrodynamic Conditions

NASA Astrophysics Data System (ADS)

Collins, J. H., III; Sasser, C.; Willson, C. S.

2016-12-01

Louisiana possesses over 350,000 acres of unique floating vegetated systems known as floating marshes or flotants. Floating marshes make up 70% of the Terrebonne and Barataria basin wetlands and exist in several forms, mainly thick mat or thin mat. Salt-water intrusion, nutria grazing, and high-energy wave events are believed to be some contributing factors to the degradation of floating marshes; however, there has been little investigation into the hydrodynamic effects on their structural integrity. Due to their unique nature, floating marshes could be susceptible to changes in the hydrodynamic environment that may result from proposed river freshwater and sediment diversion projects introducing flow to areas that are typically somewhat isolated. This study aims to improve the understanding of how thin mat floating marshes respond to increased hydrodynamic stresses and, more specifically, how higher water velocities might increase the washout probability of this vegetation type. There are two major components of this research: 1) A thorough measurement of the material properties of the vegetative mats as a root-soil matrix composite material; and 2) An accurate numerical simulation of the hydrodynamics and forces imposed on the floating marsh mats by the flow. To achieve these goals, laboratory and field experiments were conducted using a customized device to measure the bulk properties of typical floating marshes. Additionally, Delft-3D FLOW and ANSYS FLUENT were used to simulate the flow around a series of simplified mat structures in order to estimate the hydrodynamic forcings on the mats. The hydrodynamic forcings are coupled with a material analysis, allowing for a thorough analysis of their interaction under various conditions. The 2-way Fluid Structure Interaction (F.S.I.) between the flow and the mat is achieved by coupling a Finite Element Analysis (F.E.A.) solver in ANSYS with FLUENT. The flow conditions necessary for the structural failure of the floating marshes are determined for a multitude of mat shapes and sizes, leading to a quantifiable critical velocity required for washout. Ultimately, through dimensional analysis, an equation for washout potential will be developed from the results, which could be used as a design guideline.

Stability of surface plastic flow in large strain deformation of metals

NASA Astrophysics Data System (ADS)

Viswanathan, Koushik; Udapa, Anirduh; Sagapuram, Dinakar; Mann, James; Chandrasekar, Srinivasan

We examine large-strain unconstrained simple shear deformation in metals using a model two-dimensional cutting system and high-speed in situ imaging. The nature of the deformation mode is shown to be a function of the initial microstructure state of the metal and the deformation geometry. For annealed metals, which exhibit large ductility and strain hardening capacity, the commonly assumed laminar flow mode is inherently unstable. Instead, the imposed shear is accommodated by a highly rotational flow-sinuous flow-with vortex-like components and large-amplitude folding on the mesoscale. Sinuous flow is triggered by a plastic instability on the material surface ahead of the primary region of shear. On the other hand, when the material is extensively strain-hardened prior to shear, laminar flow again becomes unstable giving way to shear banding. The existence of these flow modes is established by stability analysis of laminar flow. The role of the initial microstructure state in determining the change in stability from laminar to sinuous / shear-banded flows in metals is elucidated. The implications for cutting, forming and wear processes for metals, and to surface plasticity phenomena such as mechanochemical Rehbinder effects are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, Wentao; Vemuri, Rama Ses; Milshtein, Jarrod D.

Redox flow batteries have shown outstanding promise for grid-scale energy storage to promote utilization of renewable energy and improve grid stability. Nonaqueous battery systems can potentially achieve high energy density because of their broad voltage window. In this paper, we report a new organic redox-active material for use in a nonaqueous redox flow battery, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) that has high solubility (>2.6 M) in organic solvents. PTIO exhibits electrochemically reversible disproportionation reactions and thus can serve as both anolyte and catholyte redox materials in a symmetric flow cell. The PTIO flow battery has a moderate cell voltage of ~1.7 V andmore » shows good cyclability under both cyclic voltammetry and flow cell conditions. Moreover, we demonstrate that FTIR can offer accurate estimation of the PTIO concentration in electrolytes and determine the state of charge of the PTIO flow cell, which suggests FTIR potentially as a powerful online battery status sensor. In conclusion, this study is expected to inspire more insights in this under-addressed area of state of charge analysis aiming at operational safety and reliability of flow batteries.« less

Mapping the global journey of anthropogenic aluminum: a trade-linked multilevel material flow analysis.

PubMed

Liu, Gang; Müller, Daniel B

2013-10-15

Material cycles have become increasingly coupled and interconnected in a globalizing era. While material flow analysis (MFA) has been widely used to characterize stocks and flows along technological life cycle within a specific geographical area, trade networks among individual cycles have remained largely unexplored. Here we developed a trade-linked multilevel MFA model to map the contemporary global journey of anthropogenic aluminum. We demonstrate that the anthropogenic aluminum cycle depends substantially on international trade of aluminum in all forms and becomes highly interconnected in nature. While the Southern hemisphere is the main primary resource supplier, aluminum production and consumption concentrate in the Northern hemisphere, where we also find the largest potential for recycling. The more developed countries tend to have a substantial and increasing presence throughout the stages after bauxite refining and possess highly consumption-based cycles, thus maintaining advantages both economically and environmentally. A small group of countries plays a key role in the global redistribution of aluminum and in the connectivity of the network, which may render some countries vulnerable to supply disruption. The model provides potential insights to inform government and industry policies in resource criticality, supply chain security, value chain management, and cross-boundary environmental impacts mitigation.

Materials experiment carrier concepts definition study. Volume 2: Technical report, part 2

NASA Technical Reports Server (NTRS)

1981-01-01

A materials experiment carrier (MEC) that provides effective accommodation of the given baseline materials processing in space (MPS) payloads and demonstration of the MPS platform concept for high priority materials processing science, multidiscipline MPS investigations, host carrier for commercial MPS payloads, and system economy of orbital operations is defined. The study flow of task work is shown. Study tasks featured analysis and trades to identify the MEC system concept options.

Flows of engineered nanomaterials through the recycling process in Switzerland.

PubMed

Caballero-Guzman, Alejandro; Sun, Tianyin; Nowack, Bernd

2015-02-01

The use of engineered nanomaterials (ENMs) in diverse applications has increased during the last years and this will likely continue in the near future. As the number of applications increase, more and more waste with nanomaterials will be generated. A portion of this waste will enter the recycling system, for example, in electronic products, textiles and construction materials. The fate of these materials during and after the waste management and recycling operations is poorly understood. The aim of this work is to model the flows of nano-TiO2, nano-ZnO, nano-Ag and CNT in the recycling system in Switzerland. The basis for this study is published information on the ENMs flows on the Swiss system. We developed a method to assess their flow after recycling. To incorporate the uncertainties inherent to the limited information available, we applied a probabilistic material flow analysis approach. The results show that the recycling processes does not result in significant further propagation of nanomaterials into new products. Instead, the largest proportion will flow as waste that can subsequently be properly handled in incineration plants or landfills. Smaller fractions of ENMs will be eliminated or end up in materials that are sent abroad to undergo further recovery processes. Only a reduced amount of ENMs will flow back to the productive process of the economy in a limited number of sectors. Overall, the results suggest that risk assessment during recycling should focus on occupational exposure, release of ENMs in landfills and incineration plants, and toxicity assessment in a small number of recycled inputs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Intershot Analysis of Flows in DIII-D

NASA Astrophysics Data System (ADS)

Meyer, W. H.; Allen, S. L.; Samuell, C. M.; Howard, J.

2016-10-01

Analysis of the DIII-D flow diagnostic data require demodulation of interference images, and inversion of the resultant line integrated emissivity and flow (phase) images. Four response matrices are pre-calculated: the emissivity line integral and the line integral of the scalar product of the lines-of-site with the orthogonal unit vectors of parallel flow. Equilibrium data determines the relative weight of the component matrices used in the final flow inversion matrix. Serial processing has been used for the lower divertor viewing flow camera 800x600 pixel image. The full cross section viewing camera will require parallel processing of the 2160x2560 pixel image. We will discuss using a Posix thread pool and a Tesla K40c GPU in the processing of this data. Prepared by LLNL under Contract DE-AC52-07NA27344. This material is based upon work supported by the U.S. DOE, Office of Science, Fusion Energy Sciences.

Effect of shear stress on platelet adhesion to expanded polytetrafluoroethylene, a silicone sheet, and an endothelial cell monolayer.

PubMed

Furukawa, K S; Ushida, T; Sugano, H; Tamaki, T; Ohshima, N; Tateishi, T

2000-01-01

We visualized in real-time platelets adhering to the surface of three representative biomaterials, by using an apparatus consisting of a modified cone and plate rheometer combined with an upright epifluorescence microscope under two shear flows (0.1 and 5.0 dyne/cm2). The materials were expanded polytetrafluoroethylene (ePTFE), silicone sheet, and a monolayer of bovine endothelial cells (ECs) formed on glass, all of which are opaque materials used for artificial blood vessels and medical devices. According to quantitative analysis, the monolayer of ECs formed on glass had better blood compatibility than did either the ePTFE or the silicone sheet under shear flow conditions. Under a shear flow condition of 0.1 dyne/cm2, platelet adhesion was silicone sheet > ePTFE. In contrast, under a shear flow condition of 5.0 dyne/cm2, ePTFE > silicone sheet. These results indicate that the intensity of shear stress could modify the order of hemocompatibility of the materials. Therefore, direct observation of platelet adhesion under shear flow conditions is indispensable for testing and screening biomaterials and for providing a precise quantitative evaluation of platelet adhesion.

Visualization and Hierarchical Analysis of Flow in Discrete Fracture Network Models

NASA Astrophysics Data System (ADS)

Aldrich, G. A.; Gable, C. W.; Painter, S. L.; Makedonska, N.; Hamann, B.; Woodring, J.

2013-12-01

Flow and transport in low permeability fractured rock is primary in interconnected fracture networks. Prediction and characterization of flow and transport in fractured rock has important implications in underground repositories for hazardous materials (eg. nuclear and chemical waste), contaminant migration and remediation, groundwater resource management, and hydrocarbon extraction. We have developed methods to explicitly model flow in discrete fracture networks and track flow paths using passive particle tracking algorithms. Visualization and analysis of particle trajectory through the fracture network is important to understanding fracture connectivity, flow patterns, potential contaminant pathways and fast paths through the network. However, occlusion due to the large number of highly tessellated and intersecting fracture polygons preclude the effective use of traditional visualization methods. We would also like quantitative analysis methods to characterize the trajectory of a large number of particle paths. We have solved these problems by defining a hierarchal flow network representing the topology of particle flow through the fracture network. This approach allows us to analyses the flow and the dynamics of the system as a whole. We are able to easily query the flow network, and use paint-and-link style framework to filter the fracture geometry and particle traces based on the flow analytics. This allows us to greatly reduce occlusion while emphasizing salient features such as the principal transport pathways. Examples are shown that demonstrate the methodology and highlight how use of this new method allows quantitative analysis and characterization of flow and transport in a number of representative fracture networks.

Jet Engine Exhaust Analysis by Subtractive Chromatography

DTIC Science & Technology

1978-12-01

FID B response = oxygenates + aromatics. Oxygenated compounds with 8 Tenax GC Carbosieve B Glass Wool Glass wool Glass Wool Sample Flow Desoption...sorbent samplinq. During the process of compiling this information a new series of sorbent materials that show promising sorbent characteristics was...produced by a process which "carbonizes" a porous polymer material. The pro- duct is a hard, shiny, black-beaded material. The promotional literature

[Cointegration test and variance decomposition for the relationship between economy and environment based on material flow analysis in Tangshan City Hebei China].

PubMed

2015-12-01

The material flow account of Tangshan City was established by material flow analysis (MFA) method to analyze the periodical characteristics of material input and output in the operation of economy-environment system, and the impact of material input and output intensities on economic development. Using econometric model, the long-term interaction mechanism and relationship among the indexes of gross domestic product (GDP) , direct material input (DMI), domestic processed output (DPO) were investigated after unit root hypothesis test, Johansen cointegration test, vector error correction model, impulse response function and variance decomposition. The results showed that during 1992-2011, DMI and DPO both increased, and the growth rate of DMI was higher than that of DPO. The input intensity of DMI increased, while the intensity of DPO fell in volatility. Long-term stable cointegration relationship existed between GDP, DMI and DPO. Their interaction relationship showed a trend from fluctuation to gradual ste adiness. DMI and DPO had strong, positive impacts on economic development in short-term, but the economy-environment system gradually weakened these effects by short-term dynamically adjusting indicators inside and outside of the system. Ultimately, the system showed a long-term equilibrium relationship. The effect of economic scale on economy was gradually increasing. After decomposing the contribution of each index to GDP, it was found that DMI's contribution grew, GDP's contribution declined, DPO's contribution changed little. On the whole, the economic development of Tangshan City has followed the traditional production path of resource-based city, mostly depending on the material input which caused high energy consumption and serous environmental pollution.

Multiphysics Nuclear Thermal Rocket Thrust Chamber Analysis

NASA Technical Reports Server (NTRS)

Wang, Ten-See

2005-01-01

The objective of this effort is t o develop an efficient and accurate thermo-fluid computational methodology to predict environments for hypothetical thrust chamber design and analysis. The current task scope is to perform multidimensional, multiphysics analysis of thrust performance and heat transfer analysis for a hypothetical solid-core, nuclear thermal engine including thrust chamber and nozzle. The multiphysics aspects of the model include: real fluid dynamics, chemical reactivity, turbulent flow, and conjugate heat transfer. The model will be designed to identify thermal, fluid, and hydrogen environments in all flow paths and materials. This model would then be used to perform non- nuclear reproduction of the flow element failures demonstrated in the Rover/NERVA testing, investigate performance of specific configurations and assess potential issues and enhancements. A two-pronged approach will be employed in this effort: a detailed analysis of a multi-channel, flow-element, and global modeling of the entire thrust chamber assembly with a porosity modeling technique. It is expected that the detailed analysis of a single flow element would provide detailed fluid, thermal, and hydrogen environments for stress analysis, while the global thrust chamber assembly analysis would promote understanding of the effects of hydrogen dissociation and heat transfer on thrust performance. These modeling activities will be validated as much as possible by testing performed by other related efforts.

A symmetric organic-based nonaqueous redox flow battery and its state of charge diagnostics by FTIR

DOE PAGES

Duan, Wentao; Vemuri, Rama Ses; Milshtein, Jarrod D.; ...

2016-03-10

Redox flow batteries have shown outstanding promise for grid-scale energy storage to promote utilization of renewable energy and improve grid stability. Nonaqueous battery systems can potentially achieve high energy density because of their broad voltage window. In this paper, we report a new organic redox-active material for use in a nonaqueous redox flow battery, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) that has high solubility (>2.6 M) in organic solvents. PTIO exhibits electrochemically reversible disproportionation reactions and thus can serve as both anolyte and catholyte redox materials in a symmetric flow cell. The PTIO flow battery has a moderate cell voltage of ~1.7 V andmore » shows good cyclability under both cyclic voltammetry and flow cell conditions. Moreover, we demonstrate that FTIR can offer accurate estimation of the PTIO concentration in electrolytes and determine the state of charge of the PTIO flow cell, which suggests FTIR potentially as a powerful online battery status sensor. In conclusion, this study is expected to inspire more insights in this under-addressed area of state of charge analysis aiming at operational safety and reliability of flow batteries.« less

Finite Element Analysis of Morphing Piezoelectric Structures Studied

NASA Technical Reports Server (NTRS)

Lee, Ho-Jun

2002-01-01

The development of morphing aerospace structures that optimize their shape offers the potential to significantly improve the performance of existing airplanes. These morphing vehicles will operate with new capabilities to reduce noise, damp vibrations, manipulate flow, and monitor damage. Piezoelectric materials represent one of the popular materials currently being investigated for applications in morphing structures.

MARTINS: A foam/film flow model for molten material relocation in HWRs with U-Al-fueled multi-tube assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalimullah

1994-03-01

Some special purpose heavy-water reactors (EM) are made of assemblies consisting of a number of coaxial aluminum-clad U-Al alloy fuel tubes and an outer Al sleeve surrounding the fuel tubes. The heavy water coolant flows in the annular gaps between the circular tubes. Analysis of severe accidents in such reactors requires a model for predicting the behavior of the fuel tubes as they melt and disrupt. This paper describes a detailed, mechanistic model for fuel tube heatup, melting, freezing, and molten material relocation, called MARTINS (Melting and Relocation of Tubes in Nuclear subassembly). The paper presents the modeling of themore » phenomena in MARTINS, and an application of the model to analysis of a reactivity insertion accident. Some models are being developed to compute gradual downward relocation of molten material at decay-heat power levels via candling along intact tubes, neglecting coolant vapor hydrodynamic forces on molten material. These models are inadequate for high power accident sequences involving significant hydrodynamic forces. These forces are included in MARTINS.« less

Test and Analysis of Solid Rocket Motor Nozzle Ablative Materials

NASA Technical Reports Server (NTRS)

Clayton, J. Louie

2017-01-01

Asbestos free solid motor internal insulation samples were tested at the MSFC Hyperthermal Facility. Objectives of the test were to gather data for analog characterization of ablative and in-depth thermal performance of rubber materials subject to high enthalpy/pressure flow conditions. Tests were conducted over a range of convective heat fluxes for both inert and chemically reactive sub-sonic free stream gas flow. Instrumentation included use of total calorimeters, thermocouples, and a surface pyrometer for surface temperature measurement. Post-test sample forensics involved measurement of eroded depth, charred depth, total sample weight loss, and documentation of the general condition of the eroded profile. A complete Charring Material Ablator (CMA) style aero-thermal analysis was conducted for the test matrix and results compared to the measured data. In general, comparisons were possible for a number of the cases and the results show a limited predictive ability to model accurately both the ablative response and the in-depth temperature profiles. Lessons learned and modeling recommendations are made regarding future testing and modeling improvements that will increase understanding of the basic chemistry/physics associated with the complicated material ablation process of rubber materials.

Mach 14 Flow Restrictor Thermal Stress Analysis

DTIC Science & Technology

1984-08-01

tranfer analysis, thermal stress analysis, results translation from ABAQUS to PATRAN-G, and the method used to determine the heat transfer film...G, model translation into ABAQUS format, transient heat transfer analysis and thermal stress analysis input decks, results translation from ABAQUS ...TRANSLATION FROM PATRAN-G TO ABAQUS 3 ABAQUS CONSIDERATIONS 8 MATERIAL PROPERTIES OF COLUMBIUM C-103 10 USER SUBROUTINE FILM 11 TRANSIENT

Flow and Jamming of Granular Materials in a Two-dimensional Hopper

NASA Astrophysics Data System (ADS)

Tang, Junyao

Flow in a hopper is both a fertile testing ground for understanding fundamental granular flow rheology and industrially highly relevant. Despite increasing research efforts in this area, a comprehensive physical theory is still lacking for both jamming and flow of granular materials in a hopper. In this work, I have designed a two dimensional (2D) hopper experiment using photoelastic particles (particles' shape: disk or ellipse), with the goal to build a bridge between macroscopic phenomenon of hopper flow and microscopic particle-scale dynamics. Through synchronized data of particle tracking and stress distributions in particles, I have shown differences between my data of the time-averaged velocity/stress profile of 2D hopper flow with previous theoretical predictions. I have also demonstrated the importance of a mechanical stable arch near the opening on controlling hopper flow rheology and suggested a heuristic phase diagram for the hopper flow/jamming transition. Another part of this thesis work is focused on studying the impact of particle shape of particles on hopper flow. By comparing particle-tracking and photoelastic data for ellipses and disks at the appropriate length scale, I have demonstrated an important role for the rotational freedom of elliptical particles in controlling flow rheology through particle tracking and stress analysis. This work has been supported by International Fine Particle Research Institute (IFPRI) .

Rate Dependence of Elementary Rearrangements and Spatiotemporal Correlations in the 3D Flow of Soft Solids

NASA Astrophysics Data System (ADS)

Vasisht, Vishwas V.; Dutta, Sudeep K.; Del Gado, Emanuela; Blair, Daniel L.

2018-01-01

We use a combination of confocal microscopy, rheology, and molecular dynamics simulations to investigate jammed emulsions under shear, by analyzing the 3D droplets rearrangements in the shear frame. Our quantitative analysis of local dynamics reveals elementary nonaffine rearrangements that underlie the onset of the flow at small strains. We find that the mechanism of unjamming and the upturn in the material flow curve are associated to a qualitative change in spatiotemporal correlations of such rearrangements with the applied shear rate. At high shear rates, droplet clusters follow coordinated, stringlike motion. Conversely, at low shear rates, the elementary nonaffine rearrangements exhibit longer-ranged correlations, with complex spatiotemporal patterns. The 3D microscopic details provide novel insights into the specific features of the material flow curve, common to a large class of technologically relevant soft disordered solids and new fundamental ingredients for constitutive models.

Influence of material anisotropy on the hydroelastic response of composite plates in water

NASA Astrophysics Data System (ADS)

Akcabay, Deniz Tolga; Young, Yin Lu

2018-03-01

Flexible lightweight plate-like lifting surfaces in external flows have a diverse range of use from propelling and controlling marine and aerospace vehicles to converting wind and ocean energy to electrical energy. Design and analysis of such structures are complex for underwater applications where the water density is much higher than air. The hydrodynamic loads, which vary with the inflow speed, can significantly alter the dynamic response and stability. This paper focuses on the hydroelastic response of composite plates in water. The results show that the dynamics and stability of the structure can be significantly modified by taking advantage of the material anisotropic; on the contrary, careless composite material designs may lead to unwanted dynamic instability failures. The resonance frequencies, divergence speeds, and fluid loss coefficients change with material anisotropy and hydrodynamic loads. The resonance frequencies are much lower in water than in air. The critical divergence speed increases, if the principal fiber direction is oriented towards the inflow. Hydrodynamic damping is shown to be much higher than the material damping, and tend to increase with flow speed and to decrease with increasing modal frequency. The paper derives Response Amplitude Operators (RAOs) for sample composite plates in water and use them to predict the motion response when subject to stochastic flow excitations. We show how material anisotropy can be used to passively tailor the plate vibration response spectrum to limit or enhance flow-induced vibrations of the plate depending on the desired applications.

Material flow analysis for resource management towards resilient palm oil production

NASA Astrophysics Data System (ADS)

Kamahara, H.; Faisal, M.; Hasanudin, U.; Fujie, K.; Daimon, H.

2018-03-01

Biomass waste generated from palm oil mill can be considered not only as the feedstock of renewable energy but also as the nutrient-rich resources to produce organic fertilizer. This study explored the appropriate resource management towards resilient palm oil production by applying material flow analysis. This study was conducted based on two palm oil mills in Lampung, Indonesia. The results showed that the empty fruit bunch (EFB) has the largest potential in terms of amount and energy among the biomass waste. The results also showed that the palm oil mills themselves had already self-managed their energy consumption thatwas obtained from palm kernel shell and palm press fiber. Finally, this study recommended the several utilization options of EFB for improvement of soil sustainability to contribute towards resilient palm oil production.

Capillary toroid cavity detector for high pressure NMR

DOEpatents

Gerald, II, Rex E.; Chen, Michael J.; Klingler, Robert J.; Rathke, Jerome W.; ter Horst, Marc

2007-09-11

A Toroid Cavity Detector (TCD) is provided for implementing nuclear magnetic resonance (NMR) studies of chemical reactions under conditions of high pressures and temperatures. A toroid cavity contains an elongated central conductor extending within the toroid cavity. The toroid cavity and central conductor generate an RF magnetic field for NMR analysis. A flow-through capillary sample container is located within the toroid cavity adjacent to the central conductor to subject a sample material flowing through the capillary to a static magnetic field and to enable NMR spectra to be recorded of the material in the capillary under a temperature and high pressure environment.

Analysis of indentation creep

Treesearch

Don S. Stone; Joseph E. Jakes; Jonathan Puthoff; Abdelmageed A. Elmustafa

2010-01-01

Finite element analysis is used to simulate cone indentation creep in materials across a wide range of hardness, strain rate sensitivity, and work-hardening exponent. Modeling reveals that the commonly held assumption of the hardness strain rate sensitivity (mΗ) equaling the flow stress strain rate sensitivity (mσ...

High throughput liquid absorption preconcentrator sampling instrument

DOEpatents

Zaromb, Solomon; Bozen, Ralph M.

1992-01-01

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis.

High-throughput liquid-absorption preconcentrator sampling methods

DOEpatents

Zaromb, Solomon

1994-01-01

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis.

High throughput liquid absorption preconcentrator sampling instrument

DOEpatents

Zaromb, S.; Bozen, R.M.

1992-12-22

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis. 12 figs.

High-throughput liquid-absorption preconcentrator sampling methods

DOEpatents

Zaromb, S.

1994-07-12

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis. 12 figs.

Fracture Mechanics Analysis of LH2 Feed Line Flow Liners

NASA Technical Reports Server (NTRS)

James, Mark A.; Dawicke, David S.; Brzowski, Matthew B.; Raju, Ivatury S.; Elliott, Kenny B.; Harris, Charles E.

2006-01-01

Inspections of the Space Shuttle Main Engine revealed fatigue cracks growing from slots in the flow liner of the liquid hydrogen (LH2) feed lines. During flight, the flow liners experience complex loading induced by flow of LH2 and the resonance characteristics of the structure. The flow liners are made of Inconel 718 and had previously not been considered a fracture critical component. However, fatigue failure of a flow liner could have catastrophic effect on the Shuttle engines. A fracture mechanics study was performed to determine if a damage tolerance approach to life management was possible and to determine the sensitivity to the load spectra, material properties, and crack size. The load spectra were derived separately from ground tests and material properties were obtained from coupon tests. The stress-intensity factors for the fatigue cracks were determined from a shell-dynamics approach that simulated the dominant resonant frequencies. Life predictions were obtained using the NASGRO life prediction code. The results indicated that adequate life could not be demonstrated for initial crack lengths of the size that could be detected by traditional NDE techniques.

Cross-flow shearing effects on the trajectory of highly buoyant bent-over plumes

NASA Astrophysics Data System (ADS)

Tohidi, Ali; Kaye, Nigel Berkeley; Gollner, Michael J.

2017-11-01

The dynamics of highly buoyant plumes in cross-flow is ubiquitous throughout both industrial and environmental phenomena. The rise of smoke from a chimney, wastewater discharge into river currents, and dispersion of wildfire plumes are only a few instances. There have been many previous studies investigating the behavior of jets and highly buoyant plumes in cross-flow. So far, however, very little attention has been paid to the role of shearing effects in the boundary layer on the plume trajectory, particularly on the rise height. Numerical simulations and dimensional analysis are conducted to characterize the near- and far-field behavior of a highly buoyant plume in a boundary layer cross-flow. The results show that shear in the cross-flow leads to large differences in the rise height of the plume in relation to a uniform cross-flow, especially at far-field. This material is based upon work supported by the National Science Foundation under Grant No.1200560. Any opinions, findings, and conclusions or recommendations expressed in the material are of the authors and do not necessarily reflect the views of NSF.

Physico-mechanical and thermal characteristics of commercially available and newly developed dental flowable composites

NASA Astrophysics Data System (ADS)

Kamalak, Hakan; Canbay, C. Aksu; Yiğit, Oktay; Altin, Serdar

2018-03-01

In this study, we investigated the structural stability, thermal conductivity, thermal analysis, materials' homogeneity of newly developed flowable composites. 6 different dental flowable composite resins; Grandio Flow (GF), Charisma Flow (CF), Tetric N Flow (TNF), Clearfil Majesty Flow (CMF),3M Filtek Ultimate Flow (3MFU), Voco Amaris Flow (VFA) were used. Restorations were made in standard teflon molds and the materials were light-cured for 20s in a 6 mm × 2 mm teflon mould. After polymerization, samples were kept in distilled water at 37 °C/24 h .It was found that the composites have multiphase component such as metallic dopant and organic binder. The XRD investigation showed that there was a broad halo in the pattern which indicates the organic section in the composites. The FTIR results indicate the bond structure of the composites. The temperature dependence of the thermal conductivity of the composites were found below to 5 mW/K value depending on the type of the composites, which are low enough for dental application. The micro-hardness of the samples was analyzed and the result was compared.

An efficient liner cooling scheme for advanced small gas turbine combustors

NASA Technical Reports Server (NTRS)

Paskin, Marc D.; Mongia, Hukam C.; Acosta, Waldo A.

1993-01-01

A joint Army/NASA program was conducted to design, fabricate, and test an advanced, small gas turbine, reverse-flow combustor utilizing a compliant metal/ceramic (CMC) wall cooling concept. The objectives of this effort were to develop a design method (basic design data base and analysis) for the CMC cooling technique and then demonstrate its application to an advanced cycle, small, reverse-flow combustor with 3000 F burner outlet temperature. The CMC concept offers significant improvements in wall cooling effectiveness resulting in a large reduction in cooling air requirements. Therefore, more air is available for control of burner outlet temperature pattern in addition to the benefits of improved efficiency, reduced emissions, and lower smoke levels. The program was divided into four tasks. Task 1 defined component materials and localized design of the composite wall structure in conjunction with development of basic design models for the analysis of flow and heat transfer through the wall. Task 2 included implementation of the selected materials and validated design models during combustor preliminary design. Detail design of the selected combustor concept and its refinement with 3D aerothermal analysis were completed in Task 3. Task 4 covered detail drawings, process development and fabrication, and a series of burner rig tests. The purpose of this paper is to provide details of the investigation into the fundamental flow and heat transfer characteristics of the CMC wall structure as well as implementation of the fundamental analysis method for full-scale combustor design.

ASTM F739 method for testing the permeation resistance of protective clothing materials: critical analysis with proposed changes in procedure and test-cell design.

PubMed

Anna, D H; Zellers, E T; Sulewski, R

1998-08-01

ASTM (American Society for Testing and Materials) Method F739-96 specifies a test-cell design and procedures for measuring the permeation resistance of chemical protective clothing. Among the specifications are open-loop collection stream flow rates of 0.050 to 0.150 L/min for a gaseous medium. At elevated temperatures the test must be maintained within 1 degree C of the set point. This article presents a critical analysis of the effect of the collection stream flow rate on the measured permeation rate and on the temperature uniformity within the test cell. Permeation tests were conducted on four polymeric glove materials with 44 solvents at 25 degrees C. Flow rates > 0.5 L/min were necessary to obtain accurate steady-state permeation rate (SSPR) values in 25 percent of the tests. At the lower flow rates the true SSPR typically was underestimated by a factor of two or less, but errors of up to 33-fold were observed. No clear relationship could be established between the need for a higher collection stream flow rate and either the vapor pressure or the permeation rate of the solvent, but test results suggest that poor mixing within the collection chamber was a contributing factor. Temperature gradients between the challenge and collection chambers and between the bottom and the top of the collection chamber increased with the water-bath temperature and the collection stream flow rate. Use of a test cell modified to permit deeper submersion reduced the gradients to < or = 0.5 degrees C. It is recommended that all SSPR measurements include verification of the adequacy of the collection stream flow rate. For testing at nonambient temperatures, the modified test cell described here could be used to ensure temperature uniformity throughout the cell.

Evaluate the use of tanning agent in leather industry using material flow analysis, life cycle assessment and fuzzy multi-attribute decision making (FMADM)

NASA Astrophysics Data System (ADS)

Alfarisi, Salman; Sutono, Sugoro Bhakti; Sutopo, Wahyudi

2017-11-01

Tanning industry is one of the companies that produce many pollutants and cause the negative impact on the environment. In the production process of tanning leather, the use of input material need to be evaluated. The problem of waste, not only have a negative impact on the environment, but also human health. In this study, the impact of mimosa as vegetable tanning agent evaluated. This study will provide alternative solutions for improvements to the use of vegetable tanning agent. The alternative solution is change mimosa with indusol, gambier, and dulcotan. This study evaluate the vegetable tanning of some aspects using material flow analysis and life cycle assessment approach. Life cycle assessment (LCA) is used to evaluate the environmental impact of vegetable tanning agent. Alternative solution selection using fuzzy multi-attribute decision making (FMADM) approach. Results obtained by considering the environment, human toxicity, climate change, and marine aquatic ecotoxicity, is to use dulcotan.

Pneumatic jigging: Influence of operating parameters on separation efficiency of solid waste materials.

PubMed

Abd Aziz, Mohd Aizudin; Md Isa, Khairuddin; Ab Rashid, Radzuwan

2017-06-01

This article aims to provide insights into the factors that contribute to the separation efficiency of solid particles. In this study, a pneumatic jigging technique was used to assess the separation of solid waste materials that consisted of copper, glass and rubber insulator. Several initial experiments were carried out to evaluate the strengths and limitations of the technique. It is found that despite some limitations of the technique, all the samples prepared for the experiments were successfully separated. The follow-up experiments were then carried out to further assess the separation of copper wire and rubber insulator. The effects of air flow and pulse rates on the separation process were examined. The data for these follow-up experiments were analysed using a sink float analysis technique. The analysis shows that the air flow rate was very important in determining the separation efficiency. However, the separation efficiency may be influenced by the type of materials used.

Data Envelopment Analysis for steel production with the use of Total Material Requirement

NASA Astrophysics Data System (ADS)

Oyaizu, Akira; Cravioto, Jordi; Yamasue, Eiji; Daigo, Ichiro

2018-06-01

High properties of stainless steels can be achieved by adding alloying elements and/or by structure control through complex heat treatments. Evaluations of such processes have so far been made in terms of the carbon dioxide emissions emitted or the energy consumption, but less attention has been given to resource intensity and "hidden flows". Using Data Envelopment Analysis (DEA), this study evaluates the efficiency of the environmental impact, characterised through Total Material Requirement (TMR), a measurement of hidden flows, and three properties (two mechanical and one chemical) of the materials obtained after manufacturing. Out of sample of 72 stainless steels it was found that seven (SUS312L, SUS836L, SUS447J1, SUSXM27, SUS410, SUS420F2, and SUS329J4L) showed the highest comparative efficiency, and that, when classifying the sample into four groups, the production of martensitic steels showed the highest efficiency (88%), followed by ferritic and duplex (82.6% each) and lastly austenitic (43.3%).

Flow Effects on the Flammability Diagrams of Solid Fuels

NASA Technical Reports Server (NTRS)

Cordova, J. L.; Ceamanos, J.; Fernandez-Pello, A. C.; Long, R. T.; Torero, J. L.; Quintiere, J. G.

1997-01-01

A research program is currently underway with the final objective of developing a fundamental understanding of the controlling mechanisms underlying the flammability diagrams of solid combustible materials and their derived fire properties. Given that there is a high possibility of an accidental fire occurring in a space-based facility, understanding the fire properties of materials that will be used in such facilities is of critical importance. With this purpose, the flammability diagrams of the materials, as those produced by the Lateral Ignition and Flame Spread Test (LIFT) apparatus and by a new forced flow device, the Forced Flow Ignition and Flame Spread Test (FIST) apparatus, will be obtained. The specific objective of the program is to apply the new flammability apparatus, which will more accurately reflect the potential ambient conditions of space-based environments, to the characterization of the materials for space applications. This paper presents a parametric study of oxidizer flow effects on the ignition curve of the flammability diagrams of PMMA. The dependence of the ignition delay time on the external radiant flux and either the sample width (LIFT) or the flow velocity (FIST) has been studied. Although preliminary, the results indicate that natural and forced convection flow changes, affect the characteristics of the ignition curves of the flammability diagrams. The major effect on the ignition time appears to be due to convective transfer variations at the fuel surface. At high radiant fluxes or high flow velocities, however, it appears that gas phase processes become increasingly important, affecting the overall ignition delay time. A numerical analysis of the solid fuel heating and pyrolysis has also been developed. The theoretical predictions approximate the experiments well for conditions in which the gas phase induction time is negligible.

Simulation of hydrogen adsorption systems adopting the flow through cooling concept

DOE PAGES

Corgnale, Claudio; Hardy, Bruce; Chahine, Richard; ...

2014-10-13

Hydrogen storage systems based on adsorbent materials have the potential of achieving the U.S. Department of Energy (DOE) targets, especially in terms of gravimetric capacity. This paper deals with analysis of adsorption storage systems adopting the flow through cooling concept. By this approach the feeding hydrogen provides the needed cold to maintain the tank at low temperatures. Two adsorption systems have been examined and modeled adopting the Dubinin-Astakhov model, to see their performance under selected operating conditions. A first case has been analyzed, modeling a storage tank filled with carbon based material (namely MaxSorb®) and comparing the numerical outcomes withmore » the available experimental results for a 2.5 L tank. Under selected operating conditions (minimum inlet hydrogen temperature of approximately 100 K and maximum pressure on the order of 8.5 MPa) and adopting the flow through cooling concept the material shows a gravimetric capacity of about 5.7 %. A second case has been modeled, examining the same tank filled with metal organic framework material (MOF5®) under approximately the same conditions. The model shows that the latter material can achieve a (material) gravimetric capacity on the order of 11%, making the system potentially able to achieve the DOE 2017 target.« less

Evaluating temporal changes in hydraulic conductivities near karst-terrain dams: Dokan Dam (Kurdistan-Iraq)

NASA Astrophysics Data System (ADS)

Dafny, Elad; Tawfeeq, Kochar Jamal; Ghabraie, Kazem

2015-10-01

Dam sites provide an outstanding opportunity to explore dynamic changes in the groundwater flow regime because of the high hydraulic gradient rapidly induced in their surroundings. This paper investigates the temporal changes of the hydraulic conductivities of the rocks and engineered structures via a thorough analysis of hydrological data collected at the Dokam Dam, Iraq, and a numerical model that simulates the Darcian component of the seepage. Analysis of the data indicates increased seepage with time and suggests that the hydraulic conductivity of the rocks increased as the conductivity of the grout curtain decreased. Conductivity changes on the order of 10-8 m/s, in a 20-yr period were quantified using the numerical analysis. It is postulated that the changes in hydraulic properties in the vicinity of Dokan Dam are due to suspension of fine materials, interbedded in small fissures in the rocks, and re-settlement of these materials along the curtain. Consequently, the importance of the grout curtain to minimize the downstream seepage, not only as a result of the conductivity contrast with the rocks, but also as a barrier to suspended clay sediments, is demonstrated. The numerical analysis also helped us to estimate the proportion of the disconnected karstic conduit flow to the overall flow.

Optimization of multi response in end milling process of ASSAB XW-42 tool steel with liquid nitrogen cooling using Taguchi-grey relational analysis

NASA Astrophysics Data System (ADS)

Norcahyo, Rachmadi; Soepangkat, Bobby O. P.

2017-06-01

A research was conducted for the optimization of the end milling process of ASSAB XW-42 tool steel with multiple performance characteristics based on the orthogonal array with Taguchi-grey relational analysis method. Liquid nitrogen was applied as a coolant. The experimental studies were conducted under varying the liquid nitrogen cooling flow rates (FL), and the end milling process variables, i.e., cutting speed (Vc), feeding speed (Vf), and axial depth of cut (Aa). The optimized multiple performance characteristics were surface roughness (SR), flank wear (VB), and material removal rate (MRR). An orthogonal array, signal-to-noise (S/N) ratio, grey relational analysis, grey relational grade, and analysis of variance were employed to study the multiple performance characteristics. Experimental results showed that flow rate gave the highest contribution for reducing the total variation of the multiple responses, followed by cutting speed, feeding speed, and axial depth of cut. The minimum surface roughness, flank wear, and maximum material removal rate could be obtained by using the values of flow rate, cutting speed, feeding speed, and axial depth of cut of 0.5 l/minute, 109.9 m/minute, 440 mm/minute, and 0.9 mm, respectively.

The determination of levofloxacin by flow injection analysis using UV detection, potentiometry, and conductometry in pharmaceutical preparations.

PubMed

Altiokka, G; Atkosar, Z; Can, N O

2002-10-15

A flow injection analysis (FIA) using UV detection, potentiometry and conductometry for levofloxacin (LVF) are described in this study. The best solvent system was found to consist of 0.2 M acetate buffer at pH 3 having 10% MeOH. A flow rate of 1 ml min(-1) was pumped and active material was detected at 288 nm. The detection limit (LOD) and limit of quantification (LOQ) for FIA were calculated to be 3 x 10(-7) M (S/N = 3) and 1 x 10(-7) M (S/N = 10), respectively. In the analysis of tablets, the RSD values were found to be 0.83, 0.98 and 0.99 for FIA, potentiometric and conductometric methods, respectively. Copyright 2002 Elsevier Science B.V.

Bearing Tester Data Compilation Analysis, and Reporting and Bearing Math Modeling

NASA Technical Reports Server (NTRS)

1985-01-01

The magnitude and direction of fluid induced torques and forces on the 57 mm bearing cage is considered to be a contributing factor in possible cage instabilities that can produce intermittent high heating in the bearing. Analyses of the fluid forces and torques are presented. Heat generated by viscous fluid work was estimated for two flow diverter configurations and a coolant flow of 10 lbs/sec to support the thermal evaluation of the LOX Bearing Materials Tester. Results of the analysis of the LOX turbopump turbine end bearings are discussed. Coolant velocities for the no. 4 LOX turbopump turbine end bearings were estimated as a function of shaft speed and coolant flow rate. Contact angles and track width data were developed for the 57 mm bearing as functions of shaft speed, and axial and radial loads. The Advanced Dynamics of Rolling Elements (ADORE) computer program was installed on the MSFC UNIVAC 1100 and a test case successfully run. Both the text output and the plotting output were verified. The Bearing Seal and Materials Tester - Test Condition Data Base was developed. The parametric analysis of the operating characteristics of the LOX turbopump pump end bearing using the 45 mm bearing thermal model was begun.

A high precision gas flow cell for performing in situ neutron studies of local atomic structure in catalytic materials

DOE PAGES

Olds, Daniel; Page, Katharine; Paecklar, Arnold A.; ...

2017-03-17

Gas-solid interfaces enable a multitude of industrial processes, including heterogeneous catalysis; however, there are few methods available for studying the structure of this interface under operating conditions. Here, we present a new sample environment for interrogating materials under gas-flow conditions using time-of-flight neutron scattering under both constant and pulse probe gas flow. Outlined are descriptions of the gas flow cell and a commissioning example using the adsorption of N 2 by Ca-exchanged zeolite-X (Na 78–2xCa xAl 78Si 144O 384,x ≈ 38). We demonstrate sensitivities to lattice contraction and N 2 adsorption sites in the structure, with both static gas loadingmore » and gas flow. A steady-state isotope transient kinetic analysis of N 2 adsorption measured simultaneously with mass spectrometry is also demonstrated. In the experiment, the gas flow through a plugged-flow gas-solid contactor is switched between 15N 2 and 14N 2 isotopes at a temperature of 300 K and a constant pressure of 1 atm; the gas flow and mass spectrum are correlated with the structure factor determined from event-based neutron total scattering. As a result, available flow conditions, sample considerations, and future applications are discussed.« less

Field-Flow Fractionation of Carbon Nanotubes and Related Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

John P. Selegue

During the grant period, we carried out FFF studies of carbonaceous soot, single-walled and multi-walled carbon nanotubes, carbon nano-onions and polyoxometallates. FFF alone does not provide enough information to fully characterize samples, so our suite of characterization techniques grew to include light scattering (especially Photon Correlation Spectroscopy), scanning and transmission electron microscopy, thermogravimetric analysis and spectroscopic methods. We developed convenient techniques to deposit and examine minute FFF fractions by electron microscopy. In collaboration with Arthur Cammers (University of Kentucky), we used Flow Field-Flow Fractionation (Fl-FFF) to monitor the solution-phase growth of keplerates, a class of polyoxometallate (POM) nanoparticles. We monitoredmore » the evolution of Mo-POM nanostructures over the course of weeks by by using flow field-flow fractionation and corroborated the nanoparticle structures by using transmission electron microscopy (TEM). Total molybdenum in the solution and precipitate phases was monitored by using inductively coupled plasma analyses, and total Mo-POM concentration by following the UV-visible spectra of the solution phase. We observe crystallization-driven formation of (Mo132) keplerate and solution phase-driven evolution of structurally related nanoscopic species (3-60 nm). FFF analyses of other classes of materials were less successful. Attempts to analyze platelets of layered materials, including exfoliated graphite (graphene) and TaS2 and MoS2, were disappointing. We were not able to optimize flow conditions for the layered materials. The metal sulfides react with the aqueous carrier liquid and settle out of suspension quickly because of their high density.« less

Numerical analysis of air-flow and temperature field in a passenger car compartment

NASA Astrophysics Data System (ADS)

Kamar, Haslinda Mohamed; Kamsah, Nazri; Mohammad Nor, Ahmad Miski

2012-06-01

This paper presents a numerical study on the temperature field inside a passenger's compartment of a Proton Wira saloon car using computational fluid dynamics (CFD) method. The main goal is to investigate the effects of different glazing types applied onto the front and rear windscreens of the car on the distribution of air-temperature inside the passenger compartment in the steady-state conditions. The air-flow condition in the passenger's compartment is also investigated. Fluent CFD software was used to develop a three-dimensional symmetrical model of the passenger's compartment. Simplified representations of the driver and one rear passenger were incorporated into the CFD model of the passenger's compartment. Two types of glazing were considered namely clear insulated laminated tint (CIL) with a shading coefficient of 0.78 and green insulated laminate tint (GIL) with a shading coefficient of 0.5. Results of the CFD analysis were compared with those obtained when the windscreens are made up of clear glass having a shading coefficient of 0.86. Results of the CFD analysis show that for a given glazing material, the temperature of the air around the driver is slightly lower than the air around the rear passenger. Also, the use of GIL glazing material on both the front and rear windscreens significantly reduces the air temperature inside the passenger's compartment of the car. This contributes to a better thermal comfort condition to the occupants. Swirling air flow condition occurs in the passenger compartment. The air-flow intensity and velocity are higher along the side wall of the passenger's compartment compared to that along the middle section of the compartment. It was also found that the use of glazing materials on both the front and rear windscreen has no significant effects on the air-flow condition inside the passenger's compartment of the car.

Nonlinear oscillatory rheology and structure of wormlike micellar solutions and colloidal suspensions

NASA Astrophysics Data System (ADS)

Gurnon, Amanda Kate

The complex, nonlinear flow behavior of soft materials transcends industrial applications, smart material design and non-equilibrium thermodynamics. A long-standing, fundamental challenge in soft-matter science is establishing a quantitative connection between the deformation field, local microstructure and macroscopic dynamic flow properties i.e., the rheology. Soft materials are widely used in consumer products and industrial processes including energy recovery, surfactants for personal healthcare (e.g. soap and shampoo), coatings, plastics, drug delivery, medical devices and therapeutics. Oftentimes, these materials are processed by, used during, or exposed to non-equilibrium conditions for which the transient response of the complex fluid is critical. As such, designing new dynamic experiments is imperative to testing these materials and further developing micromechanical models to predict their transient response. Two of the most common classes of these soft materials stand as the focus of the present research; they are: solutions of polymer-like micelles (PLM or also known as wormlike micelles, WLM) and concentrated colloidal suspensions. In addition to their varied applications these two different classes of soft materials are also governed by different physics. In contrast, to the shear thinning behavior of the WLMs at high shear rates, the near hard-sphere colloidal suspensions are known to display increases, sometimes quite substantial, in viscosity (known as shear thickening). The stress response of these complex fluids derive from the shear-induced microstructure, thus measurements of the microstructure under flow are critical for understanding the mechanisms underlying the complex, nonlinear rheology of these complex fluids. A popular micromechanical model is reframed from its original derivation for predicting steady shear rheology of polymers and WLMs to be applicable to weakly nonlinear oscillatory shear flow. The validity, utility and limits of this constitutive model are tested by comparison with experiments on model WLM solutions. Further comparisons to the nonlinear oscillatory shear responses measured from colloidal suspensions establishes this analysis as a promising, quantitative method for understanding the underlying mechanisms responsible for the nonlinear dynamic response of complex fluids. A new experimental technique is developed to measure the microstructure of complex fluids during steady and transient shear flow using small-angle neutron scattering (SANS). The Flow-SANS experimental method is now available to the broader user communities at the NIST Center for Neutron Research, Gaithersburg, MD and the Institut Laue-Langevin, Grenoble, France. Using this new method, a model shear banding WLM solution is interrogated under steady and oscillatory shear. For the first time, the flow-SANS methods identify new metastable states for shear banding WLM solutions, thus establishing the method as capable of probing new states not accessible using traditional steady or linear oscillatory shear methods. The flow-induced three-dimensional microstructure of a colloidal suspension under steady and dynamic oscillatory shear is also measured using these rheo- and flow-SANS methods. A new structure state is identified in the shear thickening regime that proves critical for defining the "hydrocluster" microstructure state of the suspension that is responsible for shear thickening. For both the suspensions and the WLM solutions, stress-SANS rules with the measured microstructures define the individual stress components arising separately from conservative and hydrodynamic forces and these are compared with the macroscopic rheology. Analysis of these results defines the crucial length- and time-scales of the transient microstructure response. The novel dynamic microstructural measurements presented in this dissertation provide new insights into the complexities of shear thickening and shear banding flow phenomena, which are effects observed more broadly across many different types of soft materials. Consequently, the microstructure-rheology property relationships developed for these two classes of complex fluids will aid in the testing and advancement of micromechanical constitutive model development, smart material design, industrial processing and fundamental non-equilibrium thermodynamic research of a broad range of soft materials.

Integrating Spatial Land Use Analysis and Mathematical Material Flow Analysis for Nutrient Management: A Case Study of the Bang Pakong River Basin in Thailand

NASA Astrophysics Data System (ADS)

Kupkanchanakul, Wallapa; Kwonpongsagoon, Suphaphat; Bader, Hans-Peter; Scheidegger, Ruth

2015-05-01

Rivers in developing and emerging countries often lack good water quality. Tools to assess the water quality in rivers, including identification of possible sources of pollution, are therefore of increasing importance. The aim of this study is to apply mathematical material flow and spatial land use analyses to identify and geographically locate the main nitrogen and phosphorus sources and processes in Bang Pakong Basin (BPB). Potential measures to mitigate the nitrogen and phosphorus loads to the water system can then be efficiently evaluated. The combination of these two methods reveals the overall nutrient load as well as local "hot spots." This allows possible mitigation measures to be discussed with regard to their spatial location. This approach goes beyond previous work in which mathematical material flow analysis was shown to be a useful tool to investigate sources of nutrients regardless of their location. The results show that the main sources contributing nutrients to waterways are aquaculture, such as shrimp, tilapia, catfish, and sea bass farming, as well as rice paddies along the main river. Additional sources contributing nutrients to this basin are field crops, livestock, aquaculture, households, and industry. High levels of nutrient inflows come from feeds and fertilizers through aquaculture and rice cultivation. The excess nutrients run into the waterways by direct discharge from aquaculture and runoff processes from rice paddies. Scenario analysis shows that management practices for aquaculture, rice, pig, and poultry farming are key drivers for reducing nutrients in the BPB.

Integrating spatial land use analysis and mathematical material flow analysis for nutrient management: a case study of the Bang Pakong River Basin in Thailand.

PubMed

Kupkanchanakul, Wallapa; Kwonpongsagoon, Suphaphat; Bader, Hans-Peter; Scheidegger, Ruth

2015-05-01

Rivers in developing and emerging countries often lack good water quality. Tools to assess the water quality in rivers, including identification of possible sources of pollution, are therefore of increasing importance. The aim of this study is to apply mathematical material flow and spatial land use analyses to identify and geographically locate the main nitrogen and phosphorus sources and processes in Bang Pakong Basin (BPB). Potential measures to mitigate the nitrogen and phosphorus loads to the water system can then be efficiently evaluated. The combination of these two methods reveals the overall nutrient load as well as local "hot spots." This allows possible mitigation measures to be discussed with regard to their spatial location. This approach goes beyond previous work in which mathematical material flow analysis was shown to be a useful tool to investigate sources of nutrients regardless of their location. The results show that the main sources contributing nutrients to waterways are aquaculture, such as shrimp, tilapia, catfish, and sea bass farming, as well as rice paddies along the main river. Additional sources contributing nutrients to this basin are field crops, livestock, aquaculture, households, and industry. High levels of nutrient inflows come from feeds and fertilizers through aquaculture and rice cultivation. The excess nutrients run into the waterways by direct discharge from aquaculture and runoff processes from rice paddies. Scenario analysis shows that management practices for aquaculture, rice, pig, and poultry farming are key drivers for reducing nutrients in the BPB.

Materials in the economy; material flows, scarcity, and the environment

USGS Publications Warehouse

Wagner, Lorie A.

2002-01-01

The importance of materials to the economy of the United States is described, including the levels of consumption and uses of materials. The paths (or flows) that materials take from extraction, through processing, to consumer products, and then final disposition are illustrated. Scarcity and environmental issues as they relate to the flow of materials are discussed. Examples for the three main themes of the report (material flows, scarcity, and the environment) are presented.

EDDA 1.0: integrated simulation of debris flow erosion, deposition and property changes

NASA Astrophysics Data System (ADS)

Chen, H. X.; Zhang, L. M.

2015-03-01

Debris flow material properties change during the initiation, transportation and deposition processes, which influences the runout characteristics of the debris flow. A quasi-three-dimensional depth-integrated numerical model, EDDA (Erosion-Deposition Debris flow Analysis), is presented in this paper to simulate debris flow erosion, deposition and induced material property changes. The model considers changes in debris flow density, yield stress and dynamic viscosity during the flow process. The yield stress of the debris flow mixture determined at limit equilibrium using the Mohr-Coulomb equation is applicable to clear water flow, hyper-concentrated flow and fully developed debris flow. To assure numerical stability and computational efficiency at the same time, an adaptive time stepping algorithm is developed to solve the governing differential equations. Four numerical tests are conducted to validate the model. The first two tests involve a one-dimensional debris flow with constant properties and a two-dimensional dam-break water flow. The last two tests involve erosion and deposition, and the movement of multi-directional debris flows. The changes in debris flow mass and properties due to either erosion or deposition are shown to affect the runout characteristics significantly. The model is also applied to simulate a large-scale debris flow in Xiaojiagou Ravine to test the performance of the model in catchment-scale simulations. The results suggest that the model estimates well the volume, inundated area, and runout distance of the debris flow. The model is intended for use as a module in a real-time debris flow warning system.

Quantifying sources of fine sediment supplied to post-fire debris flows using fallout radionuclide tracers

NASA Astrophysics Data System (ADS)

Smith, Hugh G.; Sheridan, Gary J.; Nyman, Petter; Child, David P.; Lane, Patrick N. J.; Hotchkis, Michael A. C.; Jacobsen, Geraldine E.

2012-02-01

Fine sediment supply has been identified as an important factor contributing to the initiation of runoff-generated debris flows after fire. However, despite the significance of fines for post-fire debris flow generation, no investigations have sought to quantify sources of this material in debris flow affected catchments. In this study, we employ fallout radionuclides ( 137Cs, 210Pb ex and 239,240Pu) as tracers to measure proportional contributions of fine sediment (< 10 μm) from hillslope surface and channel bank sources to levee and terminal fan deposits formed by post-fire debris flows in two forest catchments in southeastern Australia. While 137Cs and 210Pb ex have been widely used in sediment tracing studies, application of Pu as a tracer represents a recent development and was limited to only one catchment. The ranges in estimated proportional hillslope surface contributions of fine sediment to individual debris flow deposits in each catchment were 22-69% and 32-74%. The greater susceptibility of 210Pb ex to apparent reductions in the ash content of channel deposits relative to hillslope sources resulted in its exclusion from the final analysis. No systematic change in the proportional source contributions to debris flow deposits was observed with distance downstream from channel initiation points. Instead, spatial variability in source contributions was largely influenced by the pattern of debris flow surges forming the deposits. Linking the tracing analysis with interpretation of depositional evidence allowed reconstruction of temporal sequences in sediment source contributions to debris flow surges. Hillslope source inputs dominated most elevated channel deposits such as marginal levees that were formed under peak flow conditions. This indicated the importance of hillslope runoff and fine sediment supply for debris flow generation in both catchments. In contrast, material stored within channels that was deposited during subsequent surges was predominantly channel-derived. The results demonstrate that fallout radionuclide tracers may provide unique information on changing source contributions of fine sediment during debris flow events.

A parametric study of single-wall carbon nanotube growth by laser ablation

NASA Technical Reports Server (NTRS)

Arepalli, Sivaram; Holmes, William A.; Nikolaev, Pavel; Hadjiev, Victor G.; Scott, Carl D.

2004-01-01

Results of a parametric study of carbon nanotube production by the double-pulse laser oven process are presented. The effect of various operating parameters on the production of single-wall carbon nanotubes (SWCNTs) is estimated by characterizing the nanotube material using analytical techniques, including scanning electron microscopy, transmission electron microscopy, thermo gravimetric analysis and Raman spectroscopy. The study included changing the sequence of the laser pulses, laser energy, pulse separation, type of buffer gas used, operating pressure, flow rate, inner tube diameter, as well as its material, and oven temperature. It was found that the material quality and quantity improve with deviation from normal operation parameters such as laser energy density higher than 1.5 J/cm2, pressure lower than 67 kPa, and flow rates higher than 100 sccm. Use of helium produced mainly small diameter tubes and a lower yield. The diameter of SWCNTs decreases with decreasing oven temperature and lower flow rates.

Channeling at the base of the lithosphere during the lateral flow of plume material beneath flow line hot spots

NASA Astrophysics Data System (ADS)

Sleep, Norman H.

2008-08-01

Chains of volcanic edifices lie along flow lines between plume-fed hot spots and the thin lithosphere at ridge axes. Discovery and Euterpe/Musicians Seamounts are two examples. An attractive hypothesis is that buoyant plume material flows along the base of the lithosphere perpendicular to isochrons. The plume material may conceivably flow in a broad front or flow within channels convectively eroded into the base to the lithosphere. A necessary but not sufficient condition for convective channeling is that the expected stagnant-lid heat flow for the maximum temperature of the plume material is comparable to the half-space surface heat flow of the oceanic lithosphere. Two-dimensional and three-dimensional numerical calculations confirm this inference. A second criterion for significant convective erosion is that it needs to occur before the plume material thins by lateral spreading. Scaling relationships indicate spreading and convection are closely related. Mathematically, the Nusselt number (ratio of convective to conductive heat flow in the plume material) scales with the flux (volume per time per length of flow front) of the plume material. A blob of unconfined plume material thus spreads before the lithosphere thins much and evolves to a slowly spreading and slowly convecting warm region in equilibrium with conduction into the base of the overlying lithosphere. Three-dimensional calculations illustrate this long-lasting (and hence observable) state of plume material away from its plume source. A different flow domain occurs around a stationary hot plume that continuously supplies hot material. The plume convectively erodes the overlying lithosphere, trapping the plume material near its orifice. The region of lithosphere underlain by plume material grows toward the ridge axis and laterally by convective thinning of the lithosphere at its edges. The hottest plume material channels along flow lines. Geologically, the regions of lithosphere underlain by either warm or hot plume material are likely to extend laterally away from the volcanic edifices whether or not channeling occurs.

Identification and analysis of factors affecting thermal shock resistance of ceramic materials in solar receivers

NASA Technical Reports Server (NTRS)

Hasselman, D. P. H.; Singh, J. P.; Satyamurthy, K.

1980-01-01

An analysis was conducted of the possible modes of thermal stress failure of brittle ceramics for potential use in point-focussing solar receivers. The pertinent materials properties which control thermal stress resistance were identified for conditions of steady-state and transient heat flow, convective and radiative heat transfer, thermal buckling and thermal fatigue as well as catastrophic crack propagation. Selection rules for materials with optimum thermal stress resistance for a particular thermal environment were identified. Recommendations for materials for particular components were made. The general requirements for a thermal shock testing program quantitatively meaningful for point-focussing solar receivers were outlined. Recommendations for follow-on theoretical analyses were made.

Television Traffic: A One-Way Street? A Survey and Analysis of the International Flow of Television Programme Material. Reports and Papers on Mass Communication No. 70.

ERIC Educational Resources Information Center

Nordenstreng, Kaarle; Varis, Tapio

An international inventory was made to determine the composition of television programs, particularly from the point of view of program material exported to a country outside. A survey was also made of the international networks for sales and exchanges of program material for broadcast. A report of these studies includes the scope and methods of…

Image-Processing Program

NASA Technical Reports Server (NTRS)

Roth, D. J.; Hull, D. R.

1994-01-01

IMAGEP manipulates digital image data to effect various processing, analysis, and enhancement functions. It is keyboard-driven program organized into nine subroutines. Within subroutines are sub-subroutines also selected via keyboard. Algorithm has possible scientific, industrial, and biomedical applications in study of flows in materials, analysis of steels and ores, and pathology, respectively.

Tailings dam-break flow - Analysis of sediment transport

NASA Astrophysics Data System (ADS)

Aleixo, Rui; Altinakar, Mustafa

2015-04-01

A common solution to store mining debris is to build tailings dams near the mining site. These dams are usually built with local materials such as mining debris and are more vulnerable than concrete dams (Rico et al. 2008). of The tailings and the pond water generally contain heavy metals and various toxic chemicals used in ore extraction. Thus, the release of tailings due to a dam-break can have severe ecological consequences in the environment. A tailings dam-break has many similarities with a common dam-break flow. It is highly transient and can be severely descructive. However, a significant difference is that the released sediment-water mixture will behave as a non-Newtonian flow. Existing numerical models used to simulate dam-break flows do not represent correctly the non-Newtonian behavior of tailings under a dam-break flow and may lead to unrealistic and incorrect results. The need for experiments to extract both qualitative and quantitative information regarding these flows is therefore real and actual. The present paper explores an existing experimental data base presented in Aleixo et al. (2014a,b) to further characterize the sediment transport under conditions of a severe transient flow and to extract quantitative information regarding sediment flow rate, sediment velocity, sediment-sediment interactions a among others. Different features of the flow are also described and analyzed in detail. The analysis is made by means of imaging techniques such as Particle Image Velocimetry and Particle Tracking Velocimetry that allow extracting not only the velocity field but the Lagrangian description of the sediments as well. An analysis of the results is presented and the limitations of the presented experimental approach are discussed. References Rico, M., Benito, G., Salgueiro, AR, Diez-Herrero, A. and Pereira, H.G. (2008) Reported tailings dam failures: A review of the European incidents in the worldwide context , Journal of Hazardous Materials, 152, 846-852 . Aleixo, R., Ozeren, Y., Altinakar, M. and Wren, D. (2014a) Velocity Measurements using Particle Tracking in Tailings dam Failure experiments, Proceedings of the 3rd IAHR-Europe conference, Porto, Portugal. Aleixo, R., Ozeren, Y., Altinakar, M. (2014b) Tailing dam-break analysis by means of a combined PIV-PTV tool, Proceedings of the River Flow Conference, Lausanne, Switzerland.

Thermostructural Analysis of Carbon Cloth Phenolic Material Tested at the Laser Hardened Material Evaluation Laboratory

NASA Technical Reports Server (NTRS)

Clayton, J. Louie; Ehle, Curt; Saxon, Jeff (Technical Monitor)

2002-01-01

RSRM nozzle liner components have been analyzed and tested to explore the occurrence of anomalous material performance known as pocketing erosion. Primary physical factors that contribute to pocketing seem to include the geometric permeability, which governs pore pressure magnitudes and hence load, and carbon fiber high temperature tensile strength, which defines a material limiting capability. The study reports on the results of a coupled thermostructural finite element analysis of Carbon Cloth Phenolic (CCP) material tested at the Laser Hardened Material Evaluation Laboratory (the LHMEL facility). Modeled test configurations will be limited to the special case of where temperature gradients are oriented perpendicular to the composite material ply angle. Analyses were conducted using a transient, one-dimensional flow/thermal finite element code that models pore pressure and temperature distributions and in an explicitly coupled formulation, passes this information to a 2-dimensional finite element structural model for determination of the stress/deformation behavior of the orthotropic fiber/matrix CCP. Pore pressures are generated by thermal decomposition of the phenolic resin which evolve as a multi-component gas phase which is partially trapped in the porous microstructure of the composite. The nature of resultant pressures are described by using the Darcy relationships which have been modified to permit a multi-specie mass and momentum balance including water vapor condensation. Solution to the conjugate flow/thermal equations were performed using the SINDA code. Of particular importance to this problem was the implementation of a char and deformation state dependent (geometric) permeability as describing a first order interaction between the flow/thermal and structural models. Material property models are used to characterize the solid phase mechanical stiffness and failure. Structural calculations were performed using the ABAQUS code. Iterations were made between the two codes involving the dependent variables temperature, pressure and across-ply strain level. Model results comparisons are made for three different surface heat rates and dependent variable sensitivities discussed for the various cases.

The contribution of waste management to the reduction of greenhouse gas emissions with applications in the city of Bucharest.

PubMed

Sandulescu, Elena

2004-12-01

Waste management is a key process to protect the environment and conserve resources. The contribution of appropriate waste management measures to the reduction of greenhouse gas (GHG) emissions from the city of Bucharest was studied. An analysis of the distribution of waste flows into various treatment options was conducted using the material flows and stocks analysis (MFSA). An optimum scenario (i.e. municipal solid waste stream managed as: recycling of recoverable materials, 8%; incineration of combustibles, 60%; landfilling of non-combustibles, 32%) was modelled to represent the future waste management in Bucharest with regard to its relevance towards the potential for GHG reduction. The results indicate that it can contribute by 5.5% to the reduction of the total amount of GHGs emitted from Bucharest.

Thermal analysis of a growing crystal in an aqueous solution

NASA Astrophysics Data System (ADS)

Shiomi, Yuji; Kuroda, Toshio; Ogawa, Tomoya

1980-10-01

The temperature profiles around growing crystals in aqueous solutions of Rochelle salt were measured with accuracy of 0.005°C in a two-dimensional cell which was used for elimination of thermal convection current in the cell. The temperature distribution became stationary after 2 h from injection of the mother liquid, but the concentration distribution did not become stationary because the diffusion constant of solute in the solution was much smaller than the thermal diffusivity of the solution. The growth rate was linearly proportional to the temperature gradient at every growing interface. Since crystal growth is a typical interaction process between thermal and material flow, the experimental results were analysed by such an interaction model. The analysis confirms that the material flow is limited by diffusion within a layer width of about a few hundreds micrometers on the growing interface.

The reaction efficiency of thermal energy oxygen atoms with polymeric materials

NASA Technical Reports Server (NTRS)

Koontz, S. L.; Nordine, Paul

1990-01-01

The reaction efficiency of several polymeric materials with thermal-energy (0.04 eV translational energy), ground-state (O3P) oxygen atoms was determined by exposing the materials to a room temperature gas containing a known concentration of atomic oxygen. The reaction efficiency measurements were conducted in two flowing afterglow systems of different configuration. Atomic oxygen concentration measurements, flow, transport and surface dose analysis is presented in this paper. The measured reaction efficiencies of Kapton, Mylar, polyethylene, D4-polyethylene and Tedlar are .001 to .0001 those determined with high-energy ground-state oxygen atoms in low earth orbit or in a high-velocity atom beam. D4-polyethylene exhibits a large kinetic isotope effect with atomic oxygen at thermal but not hyperthermal atom energies.

Method and apparatus for monitoring characteristics of a flow path having solid components flowing therethrough

DOEpatents

Hoskinson, Reed L [Rigby, ID; Svoboda, John M [Idaho Falls, ID; Bauer, William F [Idaho Falls, ID; Elias, Gracy [Idaho Falls, ID

2008-05-06

A method and apparatus is provided for monitoring a flow path having plurality of different solid components flowing therethrough. For example, in the harvesting of a plant material, many factors surrounding the threshing, separating or cleaning of the plant material and may lead to the inadvertent inclusion of the component being selectively harvested with residual plant materials being discharged or otherwise processed. In accordance with the present invention the detection of the selectively harvested component within residual materials may include the monitoring of a flow path of such residual materials by, for example, directing an excitation signal toward of flow path of material and then detecting a signal initiated by the presence of the selectively harvested component responsive to the excitation signal. The detected signal may be used to determine the presence or absence of a selected plant component within the flow path of residual materials.

Tensile Shear Properties of the Friction Stir Lap Welded Joints and Material Flow Mechanism Under Pulsatile Revolutions

NASA Astrophysics Data System (ADS)

Hu, Yanying; Liu, Huijie; Du, Shuaishuai

2018-06-01

The aim of the present article is to offer insight into the effects of pin profiles on interface defects, tensile shear properties, microstructures, and the material flow of friction stir lap welded joints. The results indicate that, compared to the lap joints welded by the single threaded plane pin, the three-plane threaded pin, and the triangle threaded pin, the lap joint obtained by the conventional conical threaded pin is characterized by the minimum interface defect. The alternate threads and planes on the pin provide periodical stress, leading to pulsatile material flow patterns. Under the effect of pulsatile revolutions, an asymmetrical flow field is formed around the tool. The threads on the pin force the surrounding material to flow downward. The planes cannot only promote the horizontal flow of the material by scraping, but also provide extra space for the material vertical flow. A heuristic model is established to describe the material flow mechanism during friction stir lap welding under the effect of pulsatile revolutions.

Material flow analysis of fossil fuels in China during 2000-2010.

PubMed

Wang, Sheng; Dai, Jing; Su, Meirong

2012-01-01

Since the relationship between the supply and demand of fossil fuels is on edge in the long run, the contradiction between the economic growth and limited resources will hinder the sustainable development of the Chinese society. This paper aims to analyze the input of fossil fuels in China during 2000-2010 via the material flow analysis (MFA) that takes hidden flows into account. With coal, oil, and natural gas quantified by MFA, three indexes, consumption and supply ratio (C/S ratio), resource consumption intensity (RCI), and fossil fuels productivity (FFP), are proposed to reflect the interactions between population, GDP, and fossil fuels. The results indicated that in the past 11 years, China's requirement for fossil fuels has been increasing continuously because of the growing mine productivity in domestic areas, which also leads to a single energy consumption structure as well as excessive dependence on the domestic exploitation. It is advisable to control the fossil fuels consumption by energy recycling and new energy facilities' popularization in order to lead a sustainable access to nonrenewable resources and decrease the soaring carbon emissions.

Material Flow Analysis of Fossil Fuels in China during 2000–2010

PubMed Central

Wang, Sheng; Dai, Jing; Su, Meirong

2012-01-01

Since the relationship between the supply and demand of fossil fuels is on edge in the long run, the contradiction between the economic growth and limited resources will hinder the sustainable development of the Chinese society. This paper aims to analyze the input of fossil fuels in China during 2000–2010 via the material flow analysis (MFA) that takes hidden flows into account. With coal, oil, and natural gas quantified by MFA, three indexes, consumption and supply ratio (C/S ratio), resource consumption intensity (RCI), and fossil fuels productivity (FFP), are proposed to reflect the interactions between population, GDP, and fossil fuels. The results indicated that in the past 11 years, China's requirement for fossil fuels has been increasing continuously because of the growing mine productivity in domestic areas, which also leads to a single energy consumption structure as well as excessive dependence on the domestic exploitation. It is advisable to control the fossil fuels consumption by energy recycling and new energy facilities' popularization in order to lead a sustainable access to nonrenewable resources and decrease the soaring carbon emissions. PMID:23365525

Fluid flow analysis of E-glass fiber reinforced pipe joints in oil and gas industry

NASA Astrophysics Data System (ADS)

Bobba, Sujith; Leman, Z.; Zainuddin, E. S.; Sapuan, S. M.

2018-04-01

Glass Fiber reinforced composites have become increasingly important over the past few years and now they are the first choice materials for fabricating pipes with low weight in combination with high strength and stiffness. In Oil And Gas Industry, The Pipelines transporting heavy crude oil are subjected to variable pressure waves causing fluctuating stress levels in the pipes. Computational Fluid Dynamics (CFD) analysis was performed using solid works flow stimulation software to study the effects of these pressure waves on some specified joints in the pipes. Depending on the type of heavy crude oil being used, the flow behavior indicated a considerable degree of stress levels in certain connecting joints, causing the joints to become weak over a prolonged period of use. This research proposes a new perspective that is still required to be developed regarding the change of the pipe material, fiber winding angle in those specified joints and finally implementing cad wind technology to check the output result of the stress levels so that the life of the pipes can be optimized.

AEROELASTIC SIMULATION TOOL FOR INFLATABLE BALLUTE AEROCAPTURE

NASA Technical Reports Server (NTRS)

Liever, P. A.; Sheta, E. F.; Habchi, S. D.

2006-01-01

A multidisciplinary analysis tool is under development for predicting the impact of aeroelastic effects on the functionality of inflatable ballute aeroassist vehicles in both the continuum and rarefied flow regimes. High-fidelity modules for continuum and rarefied aerodynamics, structural dynamics, heat transfer, and computational grid deformation are coupled in an integrated multi-physics, multi-disciplinary computing environment. This flexible and extensible approach allows the integration of state-of-the-art, stand-alone NASA and industry leading continuum and rarefied flow solvers and structural analysis codes into a computing environment in which the modules can run concurrently with synchronized data transfer. Coupled fluid-structure continuum flow demonstrations were conducted on a clamped ballute configuration. The feasibility of implementing a DSMC flow solver in the simulation framework was demonstrated, and loosely coupled rarefied flow aeroelastic demonstrations were performed. A NASA and industry technology survey identified CFD, DSMC and structural analysis codes capable of modeling non-linear shape and material response of thin-film inflated aeroshells. The simulation technology will find direct and immediate applications with NASA and industry in ongoing aerocapture technology development programs.

Arc Jet Test and Analysis of Asbestos Free Solid Rocket Motor Nozzle Dome Ablative Materials

NASA Technical Reports Server (NTRS)

Clayton, J. Louie

2017-01-01

Asbestos free solid motor internal insulation samples were recently tested at the MSFC Hyperthermal Arc Jet Facility. Objectives of the test were to gather data for solid rocket motor analog characterization of ablative and in-depth thermal performance of rubber materials subject to high enthalpy/pressure flow conditions. Tests were conducted over a range of convective heat fluxes for both inert and chemically reactive sub-sonic free stream gas flow. Active instrumentation included use of total calorimeters, in-depth thermocouples, and a surface pyrometer for in-situ surface temperature measurement. Post-test sample forensics involved determination of eroded depth, charred depth, total sample weight loss, and documentation of the general condition of the eroded profile. A complete Charring Material Ablator (CMA) style aero thermal analysis was conducted for the test matrix and results compared to the measured data. In general, comparisons were possible for a number of the cases and the results show a limited predictive ability to model accurately both the ablative response and the in-depth temperature profiles. Lessons learned and modeling recommendations are made regarding future testing and modeling improvements that will increase understanding of the basic chemistry/physics associated with the complicated material ablation process of rubber materials.

Open problems in active chaotic flows: Competition between chaos and order in granular materials.

PubMed

Ottino, J. M.; Khakhar, D. V.

2002-06-01

There are many systems where interaction among the elementary building blocks-no matter how well understood-does not even give a glimpse of the behavior of the global system itself. Characteristic for these systems is the ability to display structure without any external organizing principle being applied. They self-organize as a consequence of synthesis and collective phenomena and the behavior cannot be understood in terms of the systems' constitutive elements alone. A simple example is flowing granular materials, i.e., systems composed of particles or grains. How the grains interact with each other is reasonably well understood; as to how particles move, the governing law is Newton's second law. There are no surprises at this level. However, when the particles are many and the material is vibrated or tumbled, surprising behavior emerges. Systems self-organize in complex patterns that cannot be deduced from the behavior of the particles alone. Self-organization is often the result of competing effects; flowing granular matter displays both mixing and segregation. Small differences in either size or density lead to flow-induced segregation and order; similar to fluids, noncohesive granular materials can display chaotic mixing and disorder. Competition gives rise to a wealth of experimental outcomes. Equilibrium structures, obtained experimentally in quasi-two-dimensional systems, display organization in the presence of disorder, and are captured by a continuum flow model incorporating collisional diffusion and density-driven segregation. Several open issues remain to be addressed. These include analysis of segregating chaotic systems from a dynamical systems viewpoint, and understanding three-dimensional systems and wet granular systems (slurries). General aspects of the competition between chaos-enhanced mixing and properties-induced de-mixing go beyond granular materials and may offer a paradigm for other kinds of physical systems. (c) 2002 American Institute of Physics.

Timber products output and timber harvests in Alaska: projections for 1992-2010.

Treesearch

D.J. Brooks; R.W. Haynes

1994-01-01

Projections of Alaska timber products output, the derived demand for raw material, and timber harvest by owner are developed from a trend-based analysis. By using a spread-sheet model, material flows in the Alaska forest sectorare fully accounted for. Demand for Alaska national forest timber is projected and depends on product output and harvest by other owners. Key...

Improving material identification by combining x-ray and neutron tomography

NASA Astrophysics Data System (ADS)

LaManna, Jacob M.; Hussey, Daniel S.; Baltic, Eli; Jacobson, David L.

2017-09-01

X-rays and neutrons provide complementary non-destructive probes for the analysis of structure and chemical composition of materials. Contrast differences between the modes arise due to the differences in interaction with matter. Due to the high sensitivity to hydrogen, neutrons excel at separating liquid water or hydrogenous phases from the underlying structure while X-rays resolve the solid structure. Many samples of interest, such as fluid flow in porous materials or curing concrete, are stochastic or slowly changing with time which makes analysis of sequential imaging with X-rays and neutrons difficult as the sample may change between scans. To alleviate this issue, NIST has developed a system for simultaneous X-ray and neutron tomography by orienting a 90 keVpeak micro-focus X-ray tube orthogonally to a thermal neutron beam. This system allows for non-destructive, multimodal tomography of dynamic or stochastic samples while penetrating through sample environment equipment such as pressure and flow vessels. Current efforts are underway to develop methods for 2D histogram based segmentation of reconstructed volumes. By leveraging the contrast differences between X-rays and neutrons, greater histogram peak separation can occur in 2D vs 1D enabling improved material identification.

Warm Forming of Aluminum Alloys using a Coupled Thermo-Mechanical Anisotropic Material Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abedrabbo, Nader; Pourboghrat, Farhang; Carsley, John E.

Temperature-dependant anisotropic material models for two types of automotive aluminum alloys (5754-O and 5182-O) were developed and implemented in LS-Dyna as a user material subroutine (UMAT) for coupled thermo-mechanical finite element analysis (FEA) of warm forming of aluminum alloys. The anisotropy coefficients of the Barlat YLD2000 plane stress yield function for both materials were calculated for the range of temperatures 25 deg. C-260 deg. C. Curve fitting was used to calculate the anisotropy coefficients of YLD2000 and the flow stress as a function of temperature. This temperature-dependent material model was successfully applied to the coupled thermo-mechanical analysis of stretching ofmore » aluminum sheets and results were compared with experiments.« less

Silver and gold nanoparticle separation using asymmetrical flow-field flow fractionation: Influence of run conditions and of particle and membrane charges.

PubMed

Meisterjahn, Boris; Wagner, Stephan; von der Kammer, Frank; Hennecke, Dieter; Hofmann, Thilo

2016-04-01

Flow-Field Flow Fractionation (Flow-FFF), coupled with online detection systems is one of the most promising tools available for the separation and quantification of engineered nanoparticles (ENPs) in complex matrices. To correctly relate the retention of nanoparticles in the Flow-FFF-channel to the particle size, ideal separation conditions must be met. This requires optimization of the parameters that influence the separation behavior. The aim of this study was therefore to systematically investigate and evaluate the influence of parameters such as the carrier liquid, the cross flow, and the membrane material, on the separation behavior of two metallic ENPs. For this purpose the retention, recovery, and separation efficiency of sterically stabilized silver nanoparticles (AgNPs) and electrostatically stabilized gold nanoparticles (AuNPs), which represent two materials widely used in investigations on environmental fate and ecotoxicology, were investigated against a parameter matrix of three different cross-flow densities, four representative carrier solutions, and two membrane materials. The use of a complex mixture of buffers, ionic and non-ionic surfactants (FL-70 solution) together with a medium cross-flow density provided an acceptable compromise in peak quality and recovery for both types of ENPs. However, these separation conditions do not represent a perfect match for both particle types at the same time (maximized recovery at maximized retention). It could be shown that the behavior of particles within Flow-FFF channels cannot be predicted or explained purely in terms of electrostatic interactions. Particles were irreversibly lost under conditions where the measured zeta potentials suggested that there should have been sufficient electrostatic repulsion to ensure stabilization of the particles in the Flow-FFF channel resulting in good recoveries. The wide variations that we observed in ENP behavior under different conditions, together with the different behavior that has been reported in published literature for the same NPs under similar conditions, indicate a need for improvement in the membrane materials used for Flow-FFF analysis of NPs. This research has shown that careful adjustment of separation conditions can result in acceptable, but not ideal, separation conditions for two fundamentally different stabilized materials, and that it may not be possible to separate a set of different particles under ideal conditions for each particle type. This therefore needs to be taking into account in method development and when interpreting FFF results from complex samples. Copyright © 2016 Elsevier B.V. All rights reserved.

The Global Flows of Metals and Minerals

USGS Publications Warehouse

Rogich, Donald G.; Matos, Grecia R.

2008-01-01

This paper provides a preliminary review of the trends in worldwide metals and industrial minerals production and consumption based on newly developed global metals and minerals Material Flow Accounts (MFA). The MFA developed encompass data on extraction and consumption for 25 metal and mineral commodities, on a country-by-country and year-by-year basis, for the period 1970 to 2004. The data-base, jointly developed by the authors, resides with the U.S. Geological Survey (USGS) as individual commodity Excel workbooks and within a Filemaker data management system for use in analysis. Numerous national MFA have been developed to provide information on the industrial metabolism of individual countries. These MFA include material flows associated with the four commodity categories of goods that are inputs to a country's economy, agriculture, forestry, metals and minerals, and nonrenewable organic material. In some cases, the material flows associated with the creation and maintenance of the built infrastructure (such as houses, buildings, roads, airports, dams, and so forth) were also examined. The creation of global metals and industrial minerals flows is viewed as a first step in the creation of comprehensive global MFA documenting the historical and current flows of all of the four categories of physical goods that support world economies. Metals and minerals represent a major category of nonrenewable resources that humans extract from and return to the natural ecosystem. As human populations and economies have increased, metals and industrial minerals use has increased concomitantly. This dramatic growth in metals and minerals use has serious implications for both the availability of future resources and the health of the environment, which is affected by the outputs associated with their use. This paper provides an overview of a number of the trends observed by examining the database and suggests areas for future study.

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

DOEpatents

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

1995-07-04

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

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

DOEpatents

Syn, Chol K.; Lesuer, Donald R.

1995-01-01

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

Methods and Devices for Micro-Isolation, Extraction, and/or Analysis of Microscale Components

NASA Technical Reports Server (NTRS)

Wade, Lawrence A. (Inventor); Kartalov, Emil P. (Inventor); Taylor, Clive (Inventor); Shibata, Darryl (Inventor)

2014-01-01

Provided herein are devices and methods for the micro-isolation of biological cellular material. A micro-isolation apparatus described can comprise a photomask that protects regions of interest against DNA-destroying illumination. The micro-isolation apparatus can further comprise photosensitive material defining access wells following illumination and subsequent developing of the photosensitive material. The micro-isolation apparatus can further comprise a chambered microfluidic device comprising channels providing access to wells defined in photosensitive material. The micro-isolation apparatus can comprise a chambered microfluidic device without access wells defined in photosensitive material where valves control the flow of gases or liquids through the channels of the microfluidic device. Also included are methods for selectively isolating cellular material using the apparatuses described herein, as are methods for biochemical analysis of individual regions of interest of cellular material using the devices described herein. Further included are methods of making masking arrays useful for the methods described herein.

Bed Erosion Process in Geophysical Viscoplastic Fluid

NASA Astrophysics Data System (ADS)

Luu, L. H.; Philippe, P.; Chambon, G.; Vigneaux, P.; Marly, A.

2017-12-01

The bulk behavior of materials involved in geophysical fluid dynamics such as snow avalanches or debris flows has often been modeled as viscoplastic fluid that starts to flow once its stress state overcomes a critical yield value. This experimental and numerical study proposes to interpret the process of erosion in terms of solid-fluid transition for these complex materials. The experimental setup consists in a closed rectangular channel with a cavity in its base. By means of high-resolution optical velocimetry (PIV), we properly examine the typical velocity profiles of a model elasto-viscoplastic flow (Carbopol) at the vicinity of the solid-fluid interface, separating a yielded flowing layer above from an unyielded dead zone below. In parallel, numerical simulations in this expansion-contraction geometry with Augmented Lagrangian and Finite-Differences methods intend to discuss the possibility to describe the specific flow related to the existence of a dead zone, with a simple Bingham rheology. First results of this comparative analysis show a good numerical ability to capture the main scalings and flow features, such as the non-monotonous evolution of the shear stress in the boundary layer between the central plug zone and the dead zone at the bottom of the cavity.

Fluid outflows from Venus impact craters - Analysis from Magellan data

NASA Technical Reports Server (NTRS)

Asimow, Paul D.; Wood, John A.

1992-01-01

Many impact craters on Venus have unusual outflow features originating in or under the continuous ejecta blankets and continuing downhill into the surrounding terrain. These features clearly resulted from flow of low-viscosity fluids, but the identity of those fluids is not clear. In particular, it should not be assumed a priori that the fluid is an impact melt. A number of candidate processes by which impact events might generate the observed features are considered, and predictions are made concerning the rheological character of flows produce by each mechanism. A sample of outflows was analyzed using Magellan images and a model of unconstrained Bingham plastic flow on inclined planes, leading to estimates of viscosity and yield strength for the flow materials. It is argued that at least two different mechanisms have produced outflows on Venus: an erosive, channel-forming process and a depositional process. The erosive fluid is probably an impact melt, but the depositional fluid may consist of fluidized solid debris, vaporized material, and/or melt.

The effect of different beverages on the color and translucency of flowable composites.

PubMed

Karadas, Muhammet

2016-11-01

This study examined the changes in color and translucency of flowable composites after immersion in different beverages. Thirty composite samples were prepared from four flowable composites (G-aenial Universal Flo, Filtek Ultimate, Esthelite Flow Quick, and Clearfil Majesty ES Flow) and a microhybrid composite (Filtek Z-250) and stored in distilled water at 37°C for 24 h. The samples were randomly divided into seven groups and then immersed in different beverages (Red Bull, coffee, black tea, Pepsi Cola, orange juice, and distilled water) for 7 days. The CIE L*a*b* values of each sample were measured against white and black backgrounds using a spectrophotometer before and after immersion. Data were analyzed using two-way analysis of variance and Tukey's post-hoc test (p < 0.05). The color changes were significantly different among the composite materials after immersion in beverages (p < 0.05). Filtek Ultimate and Esthelite Flow Quick exhibited less discoloration than did G-aenial Universal Flo and Clearfil Majesty ES Flow. No significant difference was found between Filtek Z-250 and either Filtek Ultimate or Esthelite Flow Quick (p > 0.05). Among the beverages, black tea and coffee caused the highest discoloration of all the materials. Immersion in coffee and black tea resulted in the highest negative changes in the translucency of the materials. The degree of discoloration for the composite resins depended on the material used and drinking beverage. SCANNING 38:701-709, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Investigation of the fluid flow dynamic parameters for Newtonian and non-Newtonian materials: an approach to understanding the fluid flow-like structures within fault zones

NASA Astrophysics Data System (ADS)

Tanaka, H.; Shiomi, Y.; Ma, K.-F.

2017-11-01

To understand the fault zone fluid flow-like structure, namely the ductile deformation structure, often observed in the geological field (e.g., Ramsay and Huber The techniques of modern structure geology, vol. 1: strain analysis, Academia Press, London, 1983; Hobbs and Ord Structure geology: the mechanics of deforming metamorphic rocks, Vol. I: principles, Elsevier, Amsterdam, 2015), we applied a theoretical approach to estimate the rate of deformation, the shear stress and the time to form a streak-line pattern in the boundary layer of viscous fluids. We model the dynamics of streak lines in laminar boundary layers for Newtonian and pseudoplastic fluids and compare the results to those obtained via laboratory experiments. The structure of deformed streak lines obtained using our model is consistent with experimental observations, indicating that our model is appropriate for understanding the shear rate, flow time and shear stress based on the profile of deformed streak lines in the boundary layer in Newtonian and pseudoplastic viscous materials. This study improves our understanding of the transportation processes in fluids and of the transformation processes in fluid-like materials. Further application of this model could facilitate understanding the shear stress and time history of the fluid flow-like structure of fault zones observed in the field.[Figure not available: see fulltext.

Investigation of the flow characteristics of lunar regolith simulants under reduced gravity and vacuum on a partial-g parabolic flight

NASA Astrophysics Data System (ADS)

Reiss, Philipp; Hager, Philipp

2013-04-01

In the field of planetary and asteroid exploration missions, one of the main interests is to gain knowledge about the components of the local Regolith to understand the properties and formation of these objects and to possibly use bound elements for in-situ resource utilization (ISRU). The handling and transport of Regolith, especially within smaller scientific sampling devices and analysis instruments, is a central issue that is often underestimated. Due to its physical properties, lunar Regolith for instance has an increased risk of clogging conveying and processing devices and hence complicates the design of such systems. In most current concepts for lunar and Martian exploration missions, the excavated Regolith is fed to a storage or analysis instrument through a series of hoppers, pipes, and similar devices. This transport process is mainly affected by the flow characteristics of the Regolith, and reduced flowability or clogging could impact the success of any mission trying to handle, sample or process Regolith. As part of the Lunar In-situ Resource Experiment (LUISE), transport processes for lunar Regolith were examined. A series of experiments with representative funnel geometries were conducted on a partial-g parabolic flight under 0.38g Martian and 0.16g lunar gravity. The experiments aimed to examine key parameters for hopper designs used in sampling processes for science experiments or ISRU processes on Mars and Moon. Two different representative lunar Regolith simulants, JSC-1A and NU-LHT-2M, were used in the investigation (sample mass < 50g, grain size < 2mm). To avoid gas inclusions in the porous simulant material, the experiments were conducted under a low vacuum between 10-3 and 100kPa. 21 different funnel geometries with variable inclination angle and opening width were tested. They were designed similar to an hourglass, with two different funnels on each side. The material flow was initiated by turning the assembly upside-down. The inclination angles of the funnels varied from 55deg to 75deg in 5deg steps, both in symmetrical and asymmetrical configuration. Three opening widths were investigated, namely 8mm, 13mm, and 18mm. Although both simulant materials showed highly variable flow characteristics, a clear direct proportional dependence between flow rate and g-level was observed. With the transition to lower g-levels, the consolidation of the simulant was significantly reduced, so that in some cases the filling level of the respective hoppers raised and prevented further material flow. The cohesive character of both simulants mainly appeared at lunar gravity. Here the material flow of NU-LHT-2M occasionally came to a sudden stop or did not start at all. Steeper and wider hoppers in most cases lead to increased flow rates, whereas geometries with wider openings tended to reduce the flow continuity. Based on these results, guidelines can be established for designing conveying devices to be used for instruments on Mars or Moon.

"Batch" kinetics in flow: online IR analysis and continuous control.

PubMed

Moore, Jason S; Jensen, Klavs F

2014-01-07

Currently, kinetic data is either collected under steady-state conditions in flow or by generating time-series data in batch. Batch experiments are generally considered to be more suitable for the generation of kinetic data because of the ability to collect data from many time points in a single experiment. Now, a method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed. This approach makes use of inline IR analysis and an automated microreactor system, which allowed for rapid and tight control of the operating conditions. The conversion/residence time profiles at several temperatures were used to fit parameters to a kinetic model. This method requires significantly less time and a smaller amount of starting material compared to one-at-a-time flow experiments, and thus allows for the rapid generation of kinetic data. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An analysis of the drying process in forest fuel material

Treesearch

G.M. Byram; R.M. Nelson

2015-01-01

It is assumed that the flow of moisture in forest fuels and other woody materials is determined by the gradient of a quantity g which is a function of some property, or properties, of the moisture content. There appears to be no preferred choice for this function, hence moisture transfer equations can be based on a number of equally valid definitions of g. The physical...

Dealing with emerging waste streams: used tyre assessment in Thailand using material flow analysis.

PubMed

Jacob, Paul; Kashyap, Prakriti; Suparat, Tasawan; Visvanathan, Chettiyappan

2014-09-01

Increasing urbanisation and automobile use have given rise to an increase in global tyre waste generation. A tyre becomes waste once it wears out and is no longer fit for its original purpose, and is thus in its end-of-life state. Unlike in developed countries, where waste tyre management has already become a significant issue, it is rarely a priority waste stream in developing countries. Hence, a large quantity of waste tyres ends up either in the open environment or in landfill. In Thailand, waste tyre management is in its infancy, with increased tyre production and wider use of vehicles, but low levels of recycling, leaving scope for more appropriate policies, plans and strategies to increase waste tyre recycling. This article describes the journey of waste tyres in Thailand in terms of recycling and recovery, and disposal. Material flow analysis was used as a tool to quantify the flows and accumulation of waste tyres in Thailand in 2012. The study revealed that, in Thailand in 2012, waste tyre management was still biased towards destructive technologies (48.9%), rather than material recovery involving rubber reclamation, retreading tyres and whole and shredded tyre applications (6.7%). Despite having both economic and environmental benefits, 44.4% of used tyres in 2012 were dumped in the open environment, and the remaining 0.05% in landfills. © The Author(s) 2014.

Thermal microactuator dimension analysis

NASA Astrophysics Data System (ADS)

Azman, N. D.; Ong, N. R.; Aziz, M. H. A.; Alcain, J. B.; Haimi, W. M. W. N.; Sauli, Z.

2017-09-01

The focus of this study was to analyse the stress and thermal flow of thermal microactuator with different type of materials and parameter using COMSOL Multiphysics software. Simulations were conducted on the existing thermal actuator and integrated it to be more efficient, low cost and low power consumption. In this simulation, the U-shaped actuator was designed and five different materials of the microactuator were studied. The result showed that Si Polycrystalline was the most suitable material used to produce thermal actuator for commercialization.

Analysis of a cryolava flow-like feature on Titan

USGS Publications Warehouse

Le, Corre L.; Le, Mouelic S.; Sotin, Christophe; Combe, J.-P.; Rodriguez, S.; Barnes, J.W.; Brown, R.H.; Buratti, B.J.; Jaumann, R.; Soderblom, J.; Soderblom, L.A.; Clark, R.; Baines, K.H.; Nicholson, P.D.

2009-01-01

This paper reports on the analysis of the highest spatial resolution hyperspectral images acquired by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft during its prime mission. A bright area matches a flow-like feature coming out of a caldera-like feature observed in Synthetic Aperture Radar (SAR) data recorded by the Cassini radar experiment [Lopes et al., 2007. Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper. Icarus 186, 395-412, doi:10.1016/j.icarus.2006.09.006]. In this SAR image, the flow extends about 160 km east of the caldera. The contrast in brightness between the flow and the surroundings progressively vanishes, suggesting alteration or evolution of the composition of the cryolava during the lifetime of the eruptions. Dunes seem to cover part of this flow on its eastern end. We analyze the different terrains using the Spectral Mixing Analysis (SMA) approach of the Multiple-Endmember Linear Unmixing Model (MELSUM, Combe et al., 2008). The study area can be fully modeled by using only two types of terrains. Then, the VIMS spectra are compared with laboratory spectra of known materials in the relevant atmospheric windows (from 1 to 2.78 ??m). We considered simple molecules that could be produced during cryovolcanic events, including H2O, CO2 (using two different grain sizes), CH4 and NH3. We find that the mean spectrum of the cryoflow-like feature is not consistent with pure water ice. It can be best fitted by linear combinations of spectra of the candidate materials, showing that its composition is compatible with a mixture of H2O, CH4 and CO2.. ?? 2009 Elsevier Ltd.

[Intervening factors in attention flow of professionals injured by biological material].

PubMed

Ribeiro, Luana Cássia Miranda; Souza, Adenícia Custódia Silva E; Tipple, Anaclara Ferreira Veiga; Melo, Dulcelene Sousa; Peixoto, Myrian Karla Ayres Veronez; Munari, Denize Bouttelet

2014-06-01

To describe the barriers and facilitator factors to follow the attention flow of professionals injured by biological material in the worker perspective. Qualitative descriptive study with data collected through individual interviews with 18 injured workers, assisted in reference public units in the city of Goiânia. The content analysis was carried out with assistance of the ATLAS.ti 6.2 software, under the work organization and subjective perspectives. From the interviews regarding the barriers and facilitator factors emerged the categories: organizational structure, Support from close people, and Knowledge influence. The organized services have enabled more qualified consultations and the workers follow-up, which caused a satisfaction feeling in relation to the working environment.

Quantitative analysis of surface deformation and ductile flow in complex analogue geodynamic models based on PIV method.

NASA Astrophysics Data System (ADS)

Krýza, Ondřej; Lexa, Ondrej; Závada, Prokop; Schulmann, Karel; Gapais, Denis; Cosgrove, John

2017-04-01

Recently, a PIV (particle image velocimetry) analysis method is optical method abundantly used in many technical branches where material flow visualization and quantification is important. Typical examples are studies of liquid flow through complex channel system, gas spreading or combustion problematics. In our current research we used this method for investigation of two types of complex analogue geodynamic and tectonic experiments. First class of experiments is aimed to model large-scale oroclinal buckling as an analogue of late Paleozoic to early Mesozoic evolution of Central Asian Orogenic Belt (CAOB) resulting from nortward drift of the North-China craton towards the Siberian craton. Here we studied relationship between lower crustal and lithospheric mantle flows and upper crustal deformation respectively. A second class of experiments is focused to more general study of a lower crustal flow in indentation systems that represent a major component of some large hot orogens (e.g. Bohemian massif). The most of simulations in both cases shows a strong dependency of a brittle structures shape, that are situated in upper crust, on folding style of a middle and lower ductile layers which is influenced by rheological, geometrical and thermal conditions of different parts across shortened domain. The purpose of PIV application is to quantify material redistribution in critical domains of the model. The derivation of flow direction and calculation of strain-rate and total displacement field in analogue experiments is generally difficult and time-expensive or often performed only on a base of visual evaluations. PIV method operates with set of images, where small tracer particles are seeded within modeled domain and are assumed to faithfully follow the material flow. On base of pixel coordinates estimation the material displacement field, velocity field, strain-rate, vorticity, tortuosity etc. are calculated. In our experiments we used velocity field divergence to quantify the redistribution and flow of anatectic lower crust and to evaluate upper crust thickenning and topography evolution. As this method is very sensitive to resolution and color contrast of obtained images and used materials are mostly uniform within individual rheological layers and domains, we utilized various markers as flakes of a fluorescent wax or glitter to increase overall sensitivity. Applying this method to oroclinal buckling experiments we derived velocity field divergence associated with upper crustal deformation and evolution of topography. Scaled, dimensionless negative values of divergence reach minimum (˜ -1) in two elongated domains propagating from inflection area of modeled orocline. These values correlate with significant upper crust material removing and-or with redistribution of crustal material associated with formed pop-up and pop-down structures. Maximum positive values (˜ 0.1) correspond with material spreading alongside forming platforms that are situated in foreland of maximum elevations. Application of PIV method on lateral view, where ductile middle and lower crust is vertically folded during lithosphere shortening and indentation, revealed possibility to track melt migration from base of lower crust through interlimb area towards hinge zone of individual folds. Simultaneously with folds locking and material accumulation, whole structures are exhumed at the middle crust level. Melt flow and heat exchange with surrounding environment is responsible for increased plasticity of the middle crust marked by higher strain-rates observed inside fold envelope. It is also responsible for significant elevation above hinges during later stages of model evolution. Heterogeneous nature of deformation is well documented by heterogeneities in derived divergence field within folds interiors. Our results show distinct advantages of PIV method for post-processing of geodynamic and tectonic analogue models and demonstrate great potential of this method for quantitative processing of wide spectrum of analogue approaches to different natural systems.

Comparing urban solid waste recycling from the viewpoint of urban metabolism based on physical input-output model: A case of Suzhou in China.

PubMed

Liang, Sai; Zhang, Tianzhu

2012-01-01

Investigating impacts of urban solid waste recycling on urban metabolism contributes to sustainable urban solid waste management and urban sustainability. Using a physical input-output model and scenario analysis, urban metabolism of Suzhou in 2015 is predicted and impacts of four categories of solid waste recycling on urban metabolism are illustrated: scrap tire recycling, food waste recycling, fly ash recycling and sludge recycling. Sludge recycling has positive effects on reducing all material flows. Thus, sludge recycling for biogas is regarded as an accepted method. Moreover, technical levels of scrap tire recycling and food waste recycling should be improved to produce positive effects on reducing more material flows. Fly ash recycling for cement production has negative effects on reducing all material flows except solid wastes. Thus, other fly ash utilization methods should be exploited. In addition, the utilization and treatment of secondary wastes from food waste recycling and sludge recycling should be concerned. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis of Lean Initiatives in the Production of Naval Aviators

DTIC Science & Technology

2012-09-01

originated in the 1950s with an engineer named Eji Toyoda, and a production genius Taiichi Ohno at Toyota in Japan. Toyoda and Ohno are credited with...to flow wastes must be eliminated. Taiichi Ohno, the designer of the Toyota Production System, was obsessed with making materials flow and to...pooling between phases or blocks.  Producing quality defects . Delays (waiting).–Varying scheduling priorities for students during different blocks of

Design and fabrication of brayton cycle solar heat receiver

NASA Technical Reports Server (NTRS)

Mendelson, I.

1971-01-01

A detail design and fabrication of a solar heat receiver using lithium fluoride as the heat storage material was completed. A gas flow analysis was performed to achieve uniform flow distribution within overall pressure drop limitations. Structural analyses and allowable design criteria were developed for anticipated environments such as launch, pressure containment, and thermal cycling. A complete heat receiver assembly was fabricated almost entirely from the refractory alloy, niobium-1% zirconium.

Human life support during interplanetary travel and domicile. II - Generic Modular Flow Schematic modeling

NASA Technical Reports Server (NTRS)

Farral, Joseph F.; Seshan, P. K.; Rohatgi, Naresh K.

1991-01-01

This paper describes the Generic Modular Flow Schematic (GMFS) architecture capable of encompassing all functional elements of a physical/chemical life support system (LSS). The GMFS can be implemented to synthesize, model, analyze, and quantitatively compare many configurations of LSSs, from a simple, completely open-loop to a very complex closed-loop. The GMFS model is coded in ASPEN, a state-of-the-art chemical process simulation program, to accurately compute the material, heat, and power flow quantities for every stream in each of the subsystem functional elements (SFEs) in the chosen configuration of a life support system. The GMFS approach integrates the various SFEs and subsystems in a hierarchical and modular fashion facilitating rapid substitutions and reconfiguration of a life support system. The comprehensive ASPEN material and energy balance output is transferred to a systems and technology assessment spreadsheet for rigorous system analysis and trade studies.

Rheological Principles for Food Analysis

NASA Astrophysics Data System (ADS)

Daubert, Christopher R.; Foegeding, E. Allen

Food scientists are routinely confronted with the need to measure physical properties related to sensory texture and processing needs. These properties are determined by rheological methods, where rheology is a science devoted to the deformation and flow of all materials. Rheological properties should be considered a subset of the textural properties of foods, because the sensory detection of texture encompasses factors beyond rheological properties. Specifically, rheological methods accurately measure "force," "deformation," and "flow," and food scientists and engineers must determine how best to apply this information. For example, the flow of salad dressing from a bottle, the snapping of a candy bar, or the pumping of cream through a homogenizer are each related to the rheological properties of these materials. In this chapter, we describe fundamental concepts pertinent to the understanding of the subject and discuss typical examples of rheological tests for common foods. A glossary is included as Sect. 30.6 to clarify and summarize rheological definitions throughout the chapter.

Impact cratering calculations. Part 1: Early time results

NASA Technical Reports Server (NTRS)

Thomsen, J. M.; Sauer, F. N.; Austin, M. G.; Ruhl, S. F.; Shultz, P. H.; Orphal, D. L.

1979-01-01

Early time two dimensional finite difference calculations of laboratory scale hypervelocity impact of 0.3 g spherical 2024 aluminum projectiles into homogeneous plasticene clay targets were performed. Analysis of resulting material motions showed that energy and momentum were coupled quickly from the aluminum projectile to the target material. In the process of coupling, some of the plasticene clay target was vaporized while the projectile become severely deformed. The velocity flow field developed within the target was shown to have features similar to those found in calculations of near surface explosion cratering. Specific application of Maxwell's analytic Z-Model showed that this model can be used to describe the early time flow fields resulting from the impact cratering calculations as well, provided the flow field centers are located beneath the target surface and most of the projectile momentum is dissipated before the model is applied.

Mass, energy and material balances of SRF production process. Part 1: SRF produced from commercial and industrial waste.

PubMed

Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

2014-08-01

This paper presents the mass, energy and material balances of a solid recovered fuel (SRF) production process. The SRF is produced from commercial and industrial waste (C&IW) through mechanical treatment (MT). In this work various streams of material produced in SRF production process are analyzed for their proximate and ultimate analysis. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. Here mass balance describes the overall mass flow of input waste material in the various output streams, whereas material balance describes the mass flow of components of input waste stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. A commercial scale experimental campaign was conducted on an MT waste sorting plant to produce SRF from C&IW. All the process streams (input and output) produced in this MT plant were sampled and treated according to the CEN standard methods for SRF: EN 15442 and EN 15443. The results from the mass balance of SRF production process showed that of the total input C&IW material to MT waste sorting plant, 62% was recovered in the form of SRF, 4% as ferrous metal, 1% as non-ferrous metal and 21% was sorted out as reject material, 11.6% as fine fraction, and 0.4% as heavy fraction. The energy flow balance in various process streams of this SRF production process showed that of the total input energy content of C&IW to MT plant, 75% energy was recovered in the form of SRF, 20% belonged to the reject material stream and rest 5% belonged with the streams of fine fraction and heavy fraction. In the material balances, mass fractions of plastic (soft), plastic (hard), paper and cardboard and wood recovered in the SRF stream were 88%, 70%, 72% and 60% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC), rubber material and non-combustibles (such as stone/rock and glass particles), was found in the reject material stream. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gesellschaft fuer angewandte Mathematik und Mechanik, Scientific Annual Meeting, Universitaet Stuttgart, Federal Republic of Germany, Apr. 13-17, 1987, Reports

NASA Astrophysics Data System (ADS)

Recent experimental, theoretical, and numerical investigations of problems in applied mechanics are discussed in reviews and reports. The fields covered include vibration and stability; the mechanics of elastic and plastic materials; fluid mechanics; the numerical treatment of differential equations; finite and boundary elements; optimization, decision theory, stochastics, and actuarial analysis; applied analysis and mathematical physics; and numerical analysis. Reviews are presented on mathematical applications of geometric-optics methods, biomechanics and implant technology, vibration theory in engineering, the stiffness and strength of damaged materials, and the existence of slow steady flows of viscoelastic fluids of integral type.

Phase change based cooling for high burst mode heat loads with temperature regulation above the phase change temperature

DOEpatents

The United States of America as represented by the United States Department of Energy

2009-12-15

An apparatus and method for transferring thermal energy from a heat load is disclosed. In particular, use of a phase change material and specific flow designs enables cooling with temperature regulation well above the fusion temperature of the phase change material for medium and high heat loads from devices operated intermittently (in burst mode). Exemplary heat loads include burst mode lasers and laser diodes, flight avionics, and high power space instruments. Thermal energy is transferred from the heat load to liquid phase change material from a phase change material reservoir. The liquid phase change material is split into two flows. Thermal energy is transferred from the first flow via a phase change material heat sink. The second flow bypasses the phase change material heat sink and joins with liquid phase change material exiting from the phase change material heat sink. The combined liquid phase change material is returned to the liquid phase change material reservoir. The ratio of bypass flow to flow into the phase change material heat sink can be varied to adjust the temperature of the liquid phase change material returned to the liquid phase change material reservoir. Varying the flowrate and temperature of the liquid phase change material presented to the heat load determines the magnitude of thermal energy transferred from the heat load.

Preliminary control system design and analysis for the Space Station Furnace Facility thermal control system

NASA Technical Reports Server (NTRS)

Jackson, M. E.

1995-01-01

This report presents the Space Station Furnace Facility (SSFF) thermal control system (TCS) preliminary control system design and analysis. The SSFF provides the necessary core systems to operate various materials processing furnaces. The TCS is defined as one of the core systems, and its function is to collect excess heat from furnaces and to provide precise cold temperature control of components and of certain furnace zones. Physical interconnection of parallel thermal control subsystems through a common pump implies the description of the TCS by coupled nonlinear differential equations in pressure and flow. This report formulates the system equations and develops the controllers that cause the interconnected subsystems to satisfy flow rate tracking requirements. Extensive digital simulation results are presented to show the flow rate tracking performance.

Investigating lava-substrate interactions through flow experiments with syrup, wax, and molten basalt

NASA Astrophysics Data System (ADS)

Rumpf, M. E.; Lev, E.

2015-12-01

Among the many factors influencing the complex process of lava flow emplacement, the interaction with the substrate onto which flow is emplaced plays a central role. Lava flows are rarely emplaced onto smooth or regular surfaces. For example, at Kīlauea Volcano, Hawai'i, lava flows regularly flow over solid rock, vegetation, basaltic or silica sand, and man-made materials, including asphalt and concrete. In situ studies of lava-substrate interactions are inherently difficult, and often dangerous, to carry-out, requiring the design of controllable laboratory experiments. We investigate the effects of substrate grain size, cohesion, and roughness on flow mobility and morphology through a series of flow experiments using analog materials and molten basalt. We have developed a series of experiments that allow for adjustable substrate parameters and analyze their effects on lava flow emplacement. The first set of experiments are performed at the Fluids Mechanics Laboratory at the Lamont-Doherty Earth Observatory and focus on two analog materials: polyethylene glycol (PEG), a commercially available wax, and corn syrup. The fluids were each extruded onto a series of scaled substrate beds to replicate the emplacement of lava in a natural environment. Preliminary experiments demonstrated that irregular topography, particularly topography with a height amplitude similar to that of the flow itself, can affect flow morphology, width, and velocity by acting as local barriers or culverts to the fluid. This is expected from observations of fluid flow in natural environments. A follow-up set of experiments will be conducted in Fall 2015 at the Syracuse University (SU) Lava Project Lab. In this set, we will pour molten basalt directly onto a series of substrates representing natural environments found on the Earth and other rocky bodies in the Solar System. These experiments will allow for analysis of the effects of basaltic composition and high temperatures on lava-substrate heat transfer and mechanical interactions. Results will be used to improve current lava flow prediction models as well as increase our understanding of the evolution of volcanic regions on the Earth and other planets.

Multiverse data-flow control.

PubMed

Schindler, Benjamin; Waser, Jürgen; Ribičić, Hrvoje; Fuchs, Raphael; Peikert, Ronald

2013-06-01

In this paper, we present a data-flow system which supports comparative analysis of time-dependent data and interactive simulation steering. The system creates data on-the-fly to allow for the exploration of different parameters and the investigation of multiple scenarios. Existing data-flow architectures provide no generic approach to handle modules that perform complex temporal processing such as particle tracing or statistical analysis over time. Moreover, there is no solution to create and manage module data, which is associated with alternative scenarios. Our solution is based on generic data-flow algorithms to automate this process, enabling elaborate data-flow procedures, such as simulation, temporal integration or data aggregation over many time steps in many worlds. To hide the complexity from the user, we extend the World Lines interaction techniques to control the novel data-flow architecture. The concept of multiple, special-purpose cursors is introduced to let users intuitively navigate through time and alternative scenarios. Users specify only what they want to see, the decision which data are required is handled automatically. The concepts are explained by taking the example of the simulation and analysis of material transport in levee-breach scenarios. To strengthen the general applicability, we demonstrate the investigation of vortices in an offline-simulated dam-break data set.

Design of Friction Stir Welding Tool for Avoiding Root Flaws

PubMed Central

Ji, Shude; Xing, Jingwei; Yue, Yumei; Ma, Yinan; Zhang, Liguo; Gao, Shuangsheng

2013-01-01

In order to improve material flow behavior during friction stir welding and avoid root flaws of weld, a tool with a half-screw pin and a tool with a tapered-flute pin are suggested. The effect of flute geometry in tool pins on material flow velocity is investigated by the software ANSYS FLUENT. Numerical simulation results show that high material flow velocity appears near the rotational tool and material flow velocity rapidly decreases with the increase of distance away from the axis of the tool. Maximum material flow velocity by the tool with the tapered-flute pin appears at the beginning position of flute and the velocity decreases with the increase of flow length in flute. From the view of increasing the flow velocity of material near the bottom of the workpiece or in the middle of workpiece, the tool with the half-screw pin and the tool with the tapered-flute pin are both better than the conventional tool. PMID:28788426

Design of Friction Stir Welding Tool for Avoiding Root Flaws.

PubMed

Ji, Shude; Xing, Jingwei; Yue, Yumei; Ma, Yinan; Zhang, Liguo; Gao, Shuangsheng

2013-12-12

In order to improve material flow behavior during friction stir welding and avoid root flaws of weld, a tool with a half-screw pin and a tool with a tapered-flute pin are suggested. The effect of flute geometry in tool pins on material flow velocity is investigated by the software ANSYS FLUENT. Numerical simulation results show that high material flow velocity appears near the rotational tool and material flow velocity rapidly decreases with the increase of distance away from the axis of the tool. Maximum material flow velocity by the tool with the tapered-flute pin appears at the beginning position of flute and the velocity decreases with the increase of flow length in flute. From the view of increasing the flow velocity of material near the bottom of the workpiece or in the middle of workpiece, the tool with the half-screw pin and the tool with the tapered-flute pin are both better than the conventional tool.

Risk management and measuring productivity with POAS--point of act system.

PubMed

Akiyama, Masanori; Kondo, Tatsuya

2007-01-01

The concept of our system is not only to manage material flows, but also to provide an integrated management resource, a means of correcting errors in medical treatment, and applications to EBM through the data mining of medical records. Prior to the development of this system, electronic processing systems in hospitals did a poor job of accurately grasping medical practice and medical material flows. With POAS (Point of Act System), hospital managers can solve the so-called, "man, money, material, and information" issues inherent in the costs of healthcare. The POAS system synchronizes with each department system, from finance and accounting, to pharmacy, to imaging, and allows information exchange. We can manage Man, Material, Money and Information completely by this system. Our analysis has shown that this system has a remarkable investment effect - saving over four million dollars per year - through cost savings in logistics and business process efficiencies. In addition, the quality of care has been improved dramatically while error rates have been reduced - nearly to zero in some cases.

The Use 0f AVIRIS Imagery To Assess Clay Mineralogy And Debris-Flow Potential In Cataract Canyon, Utah: A Preliminary Report

NASA Technical Reports Server (NTRS)

Rudd, Lawrence; Merenyi, Erzsebet

2004-01-01

Worldwide debris flows destroy property and take human lives every year (Costa, 1984). As a result of extensive property damage and loss of life there is a pressing need to go beyond just describing the nature and extent of debris flows as they occur. Most of the research into debris-flow initiation has centered on rainfall, slope angle, and existing debris-flow deposits (Costa and Wieczorek, 1987). The factor of source lithology has been recently addressed by studies in the sedimentary terranes of Grand Canyon (Webb et al., 1996; Griffiths et al., 1996) and on the Colorado Plateau as a whole.3 On the Colorado Plateau shales dominated by kaolinite and illite clays are significantly more likely to be recent producers of debris-flows than are shales in which smectite clays dominate.3 Establishing the location of shales and colluvial deposits containing kaolinite and illite clays in sedimentary terranes on the Colorado Plateau is essential to predicting where debris flows are likely to occur. AVIRIS imagery can be used to distinguish between types of clay minerals (Chabrillat et al., 2001), providing the basis for surface-materials maps. The ultimate product of this study will be a model that can be used to estimate the debris-flow hazard in Cataract Canyon, Utah. This model will be based on GIS overlay analysis of debris-flow initiation factor maps, including surface-materials maps derived from AVIRIS data.

Creating Data and Modeling Enabled Hydrology Instruction Using Collaborative Approach

NASA Astrophysics Data System (ADS)

Merwade, V.; Rajib, A.; Ruddell, B. L.; Fox, S.

2017-12-01

Hydrology instruction typically involves teaching of the hydrologic cycle and the processes associated with it such as precipitation, evapotranspiration, infiltration, runoff generation and hydrograph analysis. With the availability of observed and remotely sensed data related to many hydrologic fluxes, there is an opportunity to use these data for place based learning in hydrology classrooms. However, it is not always easy and possible for an instructor to complement an existing hydrology course with new material that requires both the time and technical expertise, which the instructor may not have. The work presented here describes an effort where students create the data and modeling driven instruction material as a part of their class assignment for a hydrology course at Purdue University. The data driven hydrology education project within Science Education Resources Center (SERC) is used as a platform to publish and share the instruction material so it can be used by future students in the same course or any other course anywhere in the world. Students in the class were divided into groups, and each group was assigned a topic such as precipitation, evapotranspiration, streamflow, flow duration curve and frequency analysis. Each student in the group was then asked to get data and do some analysis for an area with specific landuse characteristic such as urban, rural and agricultural. The student contribution were then organized into learning units such that someone can do a flow duration curve analysis or flood frequency analysis to see how it changes for rural area versus urban area. The hydrology education project within SERC cyberinfrastructure enables any other instructor to adopt this material as is or through modification to suit his/her place based instruction needs.

A Network Flow Analysis of the Nitrogen Metabolism in Beijing, China.

PubMed

Zhang, Yan; Lu, Hanjing; Fath, Brian D; Zheng, Hongmei; Sun, Xiaoxi; Li, Yanxian

2016-08-16

Rapid urbanization results in high nitrogen flows and subsequent environmental consequences. In this study, we identified the main metabolic components (nitrogen inputs, flows, and outputs) and used ecological network analysis to track the direct and integral (direct + indirect) metabolic flows of nitrogen in Beijing, China, from 1996 to 2012 and to quantify the structure of Beijing's nitrogen metabolic processes. We found that Beijing's input of new reactive nitrogen (Q, which represents nitrogen obtained from the atmosphere or nitrogen-containing materials used in production and consumption to support human activities) increased from 431 Gg in 1996 to 507 Gg in 2012. Flows to the industry, atmosphere, and household, and components of the system were clearly largest, with total integrated inputs plus outputs from these nodes accounting for 31, 29, and 15%, respectively, of the total integral flows for all paths. The flows through the sewage treatment and transportation components showed marked growth, with total integrated inputs plus outputs increasing to 3.7 and 5.2 times their 1996 values, respectively. Our results can help policymakers to locate the key nodes and pathways in an urban nitrogen metabolic system so they can monitor and manage these components of the system.

Entrainment of bed material by Earth-surface mass flows: review and reformulation of depth-integrated theory

USGS Publications Warehouse

Iverson, Richard M.; Chaojun Ouyang,

2015-01-01

Earth-surface mass flows such as debris flows, rock avalanches, and dam-break floods can grow greatly in size and destructive potential by entraining bed material they encounter. Increasing use of depth-integrated mass- and momentum-conservation equations to model these erosive flows motivates a review of the underlying theory. Our review indicates that many existing models apply depth-integrated conservation principles incorrectly, leading to spurious inferences about the role of mass and momentum exchanges at flow-bed boundaries. Model discrepancies can be rectified by analyzing conservation of mass and momentum in a two-layer system consisting of a moving upper layer and static lower layer. Our analysis shows that erosion or deposition rates at the interface between layers must in general satisfy three jump conditions. These conditions impose constraints on valid erosion formulas, and they help determine the correct forms of depth-integrated conservation equations. Two of the three jump conditions are closely analogous to Rankine-Hugoniot conditions that describe the behavior of shocks in compressible gasses, and the third jump condition describes shear traction discontinuities that necessarily exist across eroding boundaries. Grain-fluid mixtures commonly behave as compressible materials as they undergo entrainment, because changes in bulk density occur as the mixtures mobilize and merge with an overriding flow. If no bulk density change occurs, then only the shear-traction jump condition applies. Even for this special case, however, accurate formulation of depth-integrated momentum equations requires a clear distinction between boundary shear tractions that exist in the presence or absence of bed erosion.

Dynamics of drinking water biofilm in flow/non-flow conditions.

PubMed

Manuel, C M; Nunes, O C; Melo, L F

2007-02-01

Drinking water biofilm formation on polyvinyl chloride (PVC), cross-linked polyethylene (PEX), high density polyethylene (HDPE) and polypropylene (PP) was followed in three different reactors operating under stagnant or continuous flow regimes. After one week, a quasi-steady state was achieved where biofilm total cell numbers per unit surface area were not affected by fluctuations in the concentration of suspended cells. Metabolically active cells in biofilms were around 17-35% of the total cells and 6-18% were able to form colony units in R(2)A medium. Microbiological analysis showed that the adhesion material and reactor design did not affect significantly the biofilm growth. However, operating under continuous flow (0.8-1.9 Pa) or stagnant water had a significant effect on biofilm formation: in stagnant waters, biofilm grew to a less extent. By applying mass balances and an asymptotic biofilm formation model to data from biofilms grown on PVC and HDPE surfaces under turbulent flow, specific growth rates of bacteria in the biofilm were found to be similar for both materials (around 0.15 day(-1)) and much lower than the specific growth rates of suspended bacteria (around 1.8 day(-1)).

Material flows accounting for Scotland shows the merits of a circular economy and the folly of territorial carbon reporting.

PubMed

Pratt, Kimberley; Lenaghan, Michael; Mitchard, Edward T A

2016-12-01

It is essential that the human race limits the environmental damage created by our consumption. A realistic pathway to limiting consumption would be to transition to a system where materials are conserved and cycled through the economy as many times as possible and as slowly as possible, greatly reducing the greenhouse gas intensive processes of resource extraction, resource processing and waste management. Material flow analysis (MFA) is a method used to understand how materials are consumed within a nation. In this study, we attempt a MFA for Scotland which links carbon emissions to material consumption using data directly based on the mass of materials used in the Scottish economy. It is the first time such an analysis has been conducted for an economy in its entirety. This study aims to create a detailed material flow account (MFA) for Scotland, compare the environmental impacts and possible policy implications of different future material consumption scenarios and consider two materials, steel and neodymium, in detail. The model estimated that 11.4 Mg per capita of materials are consumed per year in Scotland, emitting 10.7 Mg CO 2 e per capita in the process, of which, 6.7 Mg CO 2 e per capita falls under territorial carbon accounting. Only the circular economy scenario for 2050 allowed for increases in living standards without increases in carbon emissions and material consumption. This result was mirrored in the steel and neodymium case studies-environmental impacts can be minimised by a national strategy that first reduces use, and then locally reuses materials. Material consumption accounts for a large proportion of the carbon emissions of Scotland. Strategic dematerialisation, particular of materials such as steel, could support future efforts to reduce environmental impact and meet climate change targets. However, policy makers should consider consumption carbon accounting boundaries, as well as territorial boundaries, if carbon savings are to be maximised. This is because imports and recyclate sent abroad can have significant effect on the carbon emissions from material consumption. We demonstrate that the more circular an economy is, the smaller the difference between global and territorial carbon emissions, and therefore that climate change targets based solely on territorial carbon emissions create perverse incentives. The study also found that there could be areas of economic development which are compatible with environmental aims, based around encouraging reprocessing activities in developed nations.

Towards a Net Zero Building Cluster Energy Systems Analysis for a Brigade Combat Team Complex

DTIC Science & Technology

2010-05-01

of technologies, like cogeneration or combined heat and power, waste heat recovery, biomass, geother- mal energy, solar heating (and cooling), and...peaks of individual buildings; thus the needed gen- eration and back-up capacity is smaller. To develop the community energy concept, energy models...overall thermal energy system, a hydraulic flow model (Figure 5) should be used to analyze critical capacities and flows in the system. This material is

Predicting System Accidents with Model Analysis During Hybrid Simulation

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Fleming, Land D.; Throop, David R.

2002-01-01

Standard discrete event simulation is commonly used to identify system bottlenecks and starving and blocking conditions in resources and services. The CONFIG hybrid discrete/continuous simulation tool can simulate such conditions in combination with inputs external to the simulation. This provides a means for evaluating the vulnerability to system accidents of a system's design, operating procedures, and control software. System accidents are brought about by complex unexpected interactions among multiple system failures , faulty or misleading sensor data, and inappropriate responses of human operators or software. The flows of resource and product materials play a central role in the hazardous situations that may arise in fluid transport and processing systems. We describe the capabilities of CONFIG for simulation-time linear circuit analysis of fluid flows in the context of model-based hazard analysis. We focus on how CONFIG simulates the static stresses in systems of flow. Unlike other flow-related properties, static stresses (or static potentials) cannot be represented by a set of state equations. The distribution of static stresses is dependent on the specific history of operations performed on a system. We discuss the use of this type of information in hazard analysis of system designs.

Thermal Analysis of Magnetically-Coupled Pump for Cryogenic Applications

NASA Technical Reports Server (NTRS)

Senocak, Inanc; Udaykumar, H. S.; Ndri, Narcisse; Francois, Marianne; Shyy, Wei

1999-01-01

Magnetically-coupled pump is under evaluation at Kennedy Space Center for possible cryogenic applications. A major concern is the impact of low temperature fluid flows on the pump performance. As a first step toward addressing this and related issues, a computational fluid dynamics and heat transfer tool has been adopted in a pump geometry. The computational tool includes (i) a commercial grid generator to handle multiple grid blocks and complicated geometric definitions, and (ii) an in-house computational fluid dynamics and heat transfer software developed in the Principal Investigator's group at the University of Florida. Both pure-conduction and combined convection-conduction computations have been conducted. A pure-conduction analysis gives insufficient information about the overall thermal distribution. Combined convection-conduction analysis indicates the significant influence of the coolant over the entire flow path. Since 2-D simulation is of limited help, future work on full 3-D modeling of the pump using multi-materials is needed. A comprehensive and accurate model can be developed to take into account the effect of multi-phase flow in the cooling flow loop, and the magnetic interactions.

Calculational investigation of impact cratering dynamics - Material motions during the crater growth period

NASA Technical Reports Server (NTRS)

Austin, M. G.; Thomsen, J. M.; Ruhl, S. F.; Orphal, D. L.; Schultz, P. H.

1980-01-01

The considered investigation was conducted in connection with studies which are to provide a better understanding of the detailed dynamics of impact cratering processes. Such an understanding is vital for a comprehension of planetary surfaces. The investigation is the continuation of a study of impact dynamics in a uniform, nongeologic material at impact velocities achievable in laboratory-scale experiments conducted by Thomsen et al. (1979). A calculation of a 6 km/sec impact of a 0.3 g spherical 2024 aluminum projectile into low strength (50 kPa) homogeneous plasticene clay has been continued from 18 microseconds to past 600 microseconds. The cratering flow field, defined as the material flow field in the target beyond the transient cavity but well behind the outgoing shock wave, has been analyzed in detail to see how applicable the Maxwell Z-Model, developed from analysis of near-surface explosion cratering calculations, is to impact cratering

Structural Characterization of AgGaS2-type Photocatalysts for Hydrogen Production from Water Under Visible Light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Sun Hee; Shin, Namsoo; Jang, Jum Suk

Bulky AgGaS2 was synthesized as a p-type semiconductor photocatalyst by a conventional solid state reaction under N2 flow for hydrogen production under visible light. To remove the impurity phase involved in the synthesized material and improve its crystallinity, the material was treated at various temperatures of 873-1123 K under H2S flow. Impurity phases were identified as {beta}-Ga2O3 and Ag9GaS6 with Rietveld analysis of XRD, and the local coordination structure around gallium atom in AgGaS2 was investigated by EXAFS. As the H2S-treatment temperature increased, the contribution from impurity phase was diminished. When the temperature reached 1123 K, the impurity phases weremore » completely removed and the material showed the highest photocatalytic activity.« less

Paralinear Oxidation of Silicon Nitride in a Water Vapor/Oxygen Environment

NASA Technical Reports Server (NTRS)

Fox, Dennis S.; Opila, Elizabeth J.; Nguyen, QuynhGiao; Humphrey, Donald L.; Lewton, Susan M.; Gray, Hugh R. (Technical Monitor)

2002-01-01

Three silicon nitride materials were exposed to dry oxygen flowing at 0.44 cm/s at temperatures between 1200 and 1400 C. Reaction kinetics were measured with a continuously recording microbalance. Parabolic kinetics were observed. When the same materials were exposed to a 50% H2O - 50% O2 gas mixture flowing at 4.4 cm/s, all three types exhibited paralinear kinetics. The material is oxidized by water vapor to form solid silica. The protective silica is in turn volatilized by water vapor to form primarily gaseous Si(OH)4. Nonlinear least squares analysis and a paralinear kinetic model were used to determine both parabolic and linear rate constants from the kinetic data. Volatilization of the protective silica scale can result in accelerated consumption of Si3N4. Recession rates under conditions more representative of actual combustors are compared to the furnace data.

Life cycle assessment of mobile phone housing.

PubMed

Yang, Jian-xin; Wang, Ru-song; Fu, Hao; Liu, Jing-ru

2004-01-01

The life cycle assessment of the mobile phone housing in Motorola(China) Electronics Ltd. was carried out, in which materials flows and environmental emissions based on a basic production scheme were analyzed and assessed. In the manufacturing stage, such primary processes as polycarbonate molding and surface painting are included, whereas different surface finishing technologies like normal painting, electroplate, IMD and VDM etc. were assessed. The results showed that housing decoration plays a significant role within the housing life cycle. The most significant environmental impact from housing production is the photochemical ozone formation potential. Environmental impacts of different decoration techniques varied widely, for example, the electroplating technique is more environmentally friendly than VDM. VDM consumes much more energy and raw material. In addition, the results of two alternative scenarios of dematerialization showed that material flow analysis and assessment is very important and valuable in selecting an environmentally friendly process.

The coupled geochemistry of Au and As in pyrite from ore deposits and geothermal fields: monitoring fluid evolution and external forcing factors in hydrothermal systems

NASA Astrophysics Data System (ADS)

Reich, M.; Deditius, A.; Tardani, D.; Sanchez-Alfaro, P.

2014-12-01

Among the many factors influencing the complex process of lava flow emplacement, the interaction with the substrate onto which flow is emplaced plays a central role. Lava flows are rarely emplaced onto smooth or regular surfaces. For example, at Kīlauea Volcano, Hawai'i, lava flows regularly flow over solid rock, vegetation, basaltic or silica sand, and man-made materials, including asphalt and concrete. In situ studies of lava-substrate interactions are inherently difficult, and often dangerous, to carry-out, requiring the design of controllable laboratory experiments. We investigate the effects of substrate grain size, cohesion, and roughness on flow mobility and morphology through a series of flow experiments using analog materials and molten basalt. We have developed a series of experiments that allow for adjustable substrate parameters and analyze their effects on lava flow emplacement. The first set of experiments are performed at the Fluids Mechanics Laboratory at the Lamont-Doherty Earth Observatory and focus on two analog materials: polyethylene glycol (PEG), a commercially available wax, and corn syrup. The fluids were each extruded onto a series of scaled substrate beds to replicate the emplacement of lava in a natural environment. Preliminary experiments demonstrated that irregular topography, particularly topography with a height amplitude similar to that of the flow itself, can affect flow morphology, width, and velocity by acting as local barriers or culverts to the fluid. This is expected from observations of fluid flow in natural environments. A follow-up set of experiments will be conducted in Fall 2015 at the Syracuse University (SU) Lava Project Lab. In this set, we will pour molten basalt directly onto a series of substrates representing natural environments found on the Earth and other rocky bodies in the Solar System. These experiments will allow for analysis of the effects of basaltic composition and high temperatures on lava-substrate heat transfer and mechanical interactions. Results will be used to improve current lava flow prediction models as well as increase our understanding of the evolution of volcanic regions on the Earth and other planets.

Sinks as limited resources? A new indicator for evaluating anthropogenic material flows

PubMed Central

Kral, Ulrich; Brunner, Paul H.; Chen, Pi-Cheng; Chen, Sih-Rong

2014-01-01

Besides recyclables, the use of materials inevitably yields non-recyclable materials such as emissions and wastes for disposal. These flows must be directed to sinks in a way that no adverse effects arise for humans and the environment. The objective of this paper is to present a new indicator for the assessment of substance flows to sinks on a regional scale. The indicator quantifies the environmentally acceptable mass share of a substance in actual waste and emission flows, ranging from 0% as worst case to 100% as best case. This paper consists of three parts: first, the indicator is defined. Second, a methodology to determine the indicator score is presented, including (i) substance flows analysis and (ii) a distant-to-target approach based on an adaptation of the Ecological Scarcity Method 2006. Third, the metric developed is applied in three case studies including copper (Cu) and lead (Pb) in the city of Vienna, and perfluorooctane sulfonate (PFOS) in Switzerland. The following results were obtained: in Vienna, 99% of Cu flows to geogenic and anthropogenic sinks are acceptable when evaluated by the distant-to-target approach. However, the 0.7% of Cu entering urban soils and the 0.3% entering receiving waters are beyond the acceptable level. In the case of Pb, 92% of all flows into sinks prove to be acceptable, and 8% are disposed of in local landfills with limited capacity. For PFOS, 96% of all flows into sinks are acceptable. 4% cannot be evaluated due to a lack of normative criteria, despite posing a risk for human health and the environment. The examples demonstrate the need (i) for appropriate data of good quality to calculate the sink indicator and (ii) for standards, needed for the assessment of substance flows to urban soils and receiving waters. This study corroborates that the new indicator is well suited as a base for decisions regarding the control of hazardous substances in waste and environmental management. PMID:25368543

Formation mechanisms of periodic longitudinal microstructure and texture patterns in friction stir welded magnesium AZ80

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiscocks, J., E-mail: j.hiscocks@queensu.ca

Many studies of friction stir welding have shown that periodicity of metal flow around the tool pin may result in the formation of periodic differences in microstructure and texture in the weld nugget area correlated with the weld pitch. The current work investigates the periodicity of magnesium weld microtexture in the nugget region and its association with material flow using optical and electron microscopy. Two welds created in AZ80 at different processing conditions are presented in detail, one illustrating periodic longitudinal texture change, and one showing for the first time that periodic variations in texture, grain size, or composition aremore » not defining features of periodic nugget flow. While nugget texture is dominated by shear deformation, it was found here to be affected to a lesser degree by compaction of material behind the welding tool, which led to reduction in intensity of the shear texture fiber. The decreased tendency for magnesium based alloys to form periodic patterns as compared to aluminum based alloys is explained with reference to the shear textures. - Highlights: •It is shown here that periodic material flow in the nugget does not necessitate longitudinal texture patterns. •Longitudinal texture patterns are shown to be present or absent in Mg AZ80 based on processing conditions. •Texture in the nugget is mainly dictated by shear deformation, but has measurable effects from other deformation modes. •Explanation of why longitudinal texture change is frequently reported in aluminum but not magnesium alloys is provided. •A new vector visualization of material flow based on EBSD data analysis is shown.« less

Hyphenation of ultra performance liquid chromatography (UPLC) with inductively coupled plasma mass spectrometry (ICP-MS) for fast analysis of bromine containing preservatives.

PubMed

Bendahl, Lars; Hansen, Steen Honoré; Gammelgaard, Bente; Sturup, Stefan; Nielsen, Camilla

2006-02-24

Ultra performance liquid chromatography (UPLC) was coupled to inductively coupled plasma mass spectrometry (ICP-MS) for fast analysis of three bromine-containing preservatives, monitoring the 79Br and 81Br isotopes simultaneously. Due to the efficiency of the 1.7 microm column packing material, the resolution of the test substances was only slightly affected when the linear flow velocity was increased from 0.5 to 1.9 mm s(-1). However, the sensitivity of ICP-MS detection decreased when the linear flow velocity was increased from 0.5 to 1.9 mm s(-1). Analytical figures of merit were determined at an intermediate and at a high linear velocity. The precision was better than 2.2% R.S.D. and regression analysis showed that a linear response was achieved at both flow rates (R2 > 0.9993, n = 36). The analysis time was less than 4.5 min at a flow rate of 50 microL min(-1) and limits of detection and quantification were better than 3.3 and 11 microg BrL(-1), respectively. The analysis time was reduced to 2.7 min when the flow rate was increased to 90 microL min(-1) and limits of detection and quantification were better than 20 and 65 microg BrL(-1), respectively. The method was applied for quantitative analysis of bromine-containing preservatives in commercially available cosmetic products.

Klinkenberg effect in hydrodynamics of gas flow through anisotropic porous materials

NASA Astrophysics Data System (ADS)

Wałowski, Grzegorz; Filipczak, Gabriel

2017-10-01

This study discusses results of experiments on hydrodynamic assessment of gas flow through backbone (skeletal) porous materials with an anisotropic structure. The research was conducted upon materials of diversified petrographic characteristics, both natural origin (rocky, pumice) and process materials (char and coke). The study was conducted for a variety of hydrodynamic conditions, using air, as well as for nitrogen and carbon dioxide. The basis for assessing hydrodynamics of gas flow through porous material was a gas stream that results from the pressure forcing such flow. The results of measurements indicate a clear impact of the type of material on the gas permeability, and additionally - as a result of their anisotropic internal structure - to a significant effect of the flow direction on the value of gas stream.

One-dimensional analysis of supersonic two-stage HVOF process

NASA Astrophysics Data System (ADS)

Katanoda, Hiroshi; Hagi, Junichi; Fukuhara, Minoru

2009-12-01

The one-dimensional calculation of the gas/particle flows of a supersonic two-stage high-velocity oxy-fuel (HVOF) thermal spray process was performed. The internal gas flow was solved by numerically integrating the equations of the quasi-one-dimensional flow including the effects of pipe friction and heat transfer. As for the supersonic jet flow, semi-empirical equations were used to obtain the gas velocity and temperature along the center line. The velocity and temperature of the particle were obtained by an one-way coupling method. The material of the spray particle selected in this study is ultra high molecular weight polyethylene (UHMWPE). The temperature distributions in the spherical UHMWPE particles of 50 and 150µm accelerated and heated by the supersonic gas flow was clarified.

Effect of anticoagulants on the protein corona-induced reduced drug carrier adhesion efficiency in human blood flow.

PubMed

Sobczynski, Daniel J; Eniola-Adefeso, Omolola

2017-01-15

Plasma proteins rapidly coat the surfaces of particulate drug carriers to form a protein corona upon their injection into the bloodstream. The high presence of immunoglobulins in the corona formed on poly(lactic-co-glycolic acid) (PLGA) vascular-targeted carrier (VTC) surfaces was recently shown to negatively impact their adhesion to activated endothelial cells (aECs) in vitro. Here, we characterized the influence of anticoagulants, or their absence, on the binding efficiency of VTCs of various materials via modulation of their protein corona. Specifically, we evaluated the adhesion of PLGA, poly(lactic acid) (PLA), polycaprolactone (PCL), silica, and polystyrene VTCs to aECs in heparinized, citrated, and non-anticoagulated (serum and whole) blood flows relative to buffer control. Particle adhesion is substantially reduced in non-anticoagulated blood flows regardless of the material type while only moderate to minimal reduction is observed for VTCs in anticoagulant-containing blood flow depending on the anticoagulant and material type. The substantial reduction in VTC adhesion in blood flows was linked to a high presence of immunoglobulin-sized proteins in the VTC corona via SDS-PAGE analysis. Of all the materials evaluated, PLGA was the most sensitive to plasma protein effects while PCL was the most resistant, suggesting particle hydrophobicity is a critical component of the observed negative plasma protein effects. Overall, this work demonstrates that anticoagulant positively alters the effect of plasma proteins in prescribing VTC adhesion to aECs in human blood flow, which has implication in the use of in vitro blood flow assays for functional evaluation of VTCs for in vivo use. This study addresses the impact of anticoagulant on altering the extent of the previously observed protein corona-induced adhesion reduction of vascular-targeted drug carriers in human blood flows. Specifically, serum blood flow (no anticoagulant) magnifies the negative effect of the plasma protein corona on drug carrier adhesion relative to citrated or heparinized blood flows. Overall, the results from this work suggest that serum better predicts targeted drug carrier adhesion efficiency in vivo compared to anticoagulant containing plasma. Furthermore, this study offers critical insight into the importance of how the choice of anticoagulant can greatly affect drug delivery-related processes in vitro. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A multi points ultrasonic detection method for material flow of belt conveyor

NASA Astrophysics Data System (ADS)

Zhang, Li; He, Rongjun

2018-03-01

For big detection error of single point ultrasonic ranging technology used in material flow detection of belt conveyor when coal distributes unevenly or is large, a material flow detection method of belt conveyor is designed based on multi points ultrasonic counter ranging technology. The method can calculate approximate sectional area of material by locating multi points on surfaces of material and belt, in order to get material flow according to running speed of belt conveyor. The test results show that the method has smaller detection error than single point ultrasonic ranging technology under the condition of big coal with uneven distribution.

The materials flow of mercury in the economies of the United States and the world

USGS Publications Warehouse

Sznopek, John L.; Goonan, Thomas G.

2000-01-01

Although natural sources of mercury exist in the environment, measured data and modeling results indicate that the amount of mercury released into the biosphere has increased since the beginning of the industrial age. Mercury is naturally distributed in the air, water, and soil in minute amounts, and can be mobile within and between these media. Because of these properties and the subsequent impacts on human health, mercury was selected for an initial materials flow study, focusing on the United States in 1990. This study was initiated to provide a current domestic and international analysis. As part of an increased emphasis on materials flow, this report researched changes and identified the associated trends in mercury flows; it also updates statistics through 1996. In addition to domestic flows, the report includes an international section, because all primary mercury-producing mines are currently foreign, 86 percent of the mercury cell sector of the worldwide chlor-alkali industry is outside the United States, there is a large international mercury trade (1,395 t 1 in 1996), and environmental regulations are not uniform or similarly enforced from country to country. Environmental concerns have brought about numerous regulations that have dramatically decreased both the use and the production of mercury since the late 1980?s. Our study indicates that this trend is likely to continue into the future, as the world eliminates the large mercury inventories that have been stockpiled to support prior industrial processes and products.

Design and Verification of a Shape Memory Polymer Peripheral Occlusion Device

PubMed Central

Landsman, Todd L.; Bush, Ruth L.; Glowczwski, Alan; Horn, John; Jessen, Staci L.; Ungchusri, Ethan; Diguette, Katelin; Smith, Harrison R.; Hasan, Sayyeda M.; Nash, Daniel; Clubb, Fred J.; Maitland, Duncan J.

2017-01-01

Shape memory polymer foams have been previously investigated for their safety and efficacy in treating a porcine aneurysm model. Their biocompatibility, rapid thrombus formation, and ability for endovascular catheter-based delivery to a variety of vascular beds makes these foams ideal candidates for use in numerous embolic applications, particularly within the peripheral vasculature. This study sought to investigate the material properties, safety, and efficacy of a shape memory polymer peripheral embolization device in vitro. The material characteristics of the device were analyzed to show tunability of the glass transition temperature (Tg) and the expansion rate of the polymer to ensure adequate time to deliver the device through a catheter prior to excessive foam expansion. Mechanical analysis and flow migration studies were performed to ensure minimal risk of vessel perforation and undesired thromboembolism upon device deployment. The efficacy of the device was verified by performing blood flow studies that established affinity for thrombus formation and blood penetration throughout the foam and by delivery of the device in an ultrasound phantom that demonstrated flow stagnation and diversion of flow to collateral pathways. PMID:27419615

Design and verification of a shape memory polymer peripheral occlusion device.

PubMed

Landsman, Todd L; Bush, Ruth L; Glowczwski, Alan; Horn, John; Jessen, Staci L; Ungchusri, Ethan; Diguette, Katelin; Smith, Harrison R; Hasan, Sayyeda M; Nash, Daniel; Clubb, Fred J; Maitland, Duncan J

2016-10-01

Shape memory polymer foams have been previously investigated for their safety and efficacy in treating a porcine aneurysm model. Their biocompatibility, rapid thrombus formation, and ability for endovascular catheter-based delivery to a variety of vascular beds makes these foams ideal candidates for use in numerous embolic applications, particularly within the peripheral vasculature. This study sought to investigate the material properties, safety, and efficacy of a shape memory polymer peripheral embolization device in vitro. The material characteristics of the device were analyzed to show tunability of the glass transition temperature (Tg) and the expansion rate of the polymer to ensure adequate time to deliver the device through a catheter prior to excessive foam expansion. Mechanical analysis and flow migration studies were performed to ensure minimal risk of vessel perforation and undesired thromboembolism upon device deployment. The efficacy of the device was verified by performing blood flow studies that established affinity for thrombus formation and blood penetration throughout the foam and by delivery of the device in an ultrasound phantom that demonstrated flow stagnation and diversion of flow to collateral pathways. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on Edge Thickening Flow Forming Using the Finite Elements Analysis

NASA Astrophysics Data System (ADS)

Kim, Young Jin; Park, Jin Sung; Cho, Chongdu

2011-08-01

This study is to examine the forming features of flow stress property and the incremental forming method with increasing the thickness of material. Recently, the optimized forming method is widely studied through the finite element analysis to optimize forming process conditions in many different forming fields. The optimal forming method should be adopted to meet geometric requirements as the reduction in volume per unit length of material such as forging, rolling, spinning etc. However conventional studies have not dealt with issue regarding volume per unit length. For the study we use the finite element method and model a gear part of an automotive engine flywheel as the study model, which is a weld assembly of a plate and a gear with respective different thickness. In simulation of the present study, a optimized forming condition for gear machining, considering the thickness of the outer edge of flywheel is studied using the finite elements analysis for the increasing thickness of the forming method. It is concluded from the study that forming method to increase the thickness per unit length for gear machining is reasonable using the finite elements analysis and forming test.

Degradation and Deformation of Scarps and Slopes on Io: New Results

NASA Technical Reports Server (NTRS)

Moore, J. M.; Sullivan, R. J.; Pappalardo, R. T.; Turtle, E. P.

2000-01-01

Initial analysis of degradational processes on scarps and slopes on Io using just-acquired images by the Galileo SSI team. Among other results, is evidence for sublimation, sapping, and perhaps "glacial" flow of interstitial volatiles in relief-forming materials.

Flow Synthesis of Silver Nanowires for Semitransparent Solar Cell Electrodes: A Life Cycle Perspective.

PubMed

Espinosa, Nieves; Søndergaard, Roar R; Jørgensen, Mikkel; Krebs, Frederik C

2016-04-21

Silver nanowires (AgNWs) were prepared on a 5 g scale using either the well-known batch synthesis following the polyol method or a new flow synthesis method. The AgNWs were employed as semitransparent electrode materials in organic photovoltaics and compared to traditional printed silver electrodes based on micron sized silver flakes using life cycle analysis and environmental impact analysis methods. The life cycle analysis of AgNWs confirms that they provide an avenue to low-impact semitransparent electrodes. We find that the benefit of AgNWs in terms of embodied energy is less pronounced than generally assumed but that the toxicological and environmental benefits are significant. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Numerical investigation of debris materials prior to debris flow hazards using satellite images

NASA Astrophysics Data System (ADS)

Zhang, N.; Matsushima, T.

2018-05-01

The volume of debris flows occurred in mountainous areas is mainly affected by the volume of debris materials deposited at the valley bottom. Quantitative evaluation of debris materials prior to debris flow hazards is important to predict and prevent hazards. At midnight on 7th August 2010, two catastrophic debris flows were triggered by the torrential rain from two valleys in the northern part of Zhouqu City, NW China, resulting in 1765 fatalities and huge economic losses. In the present study, a depth-integrated particle method is adopted to simulate the debris materials, based on 2.5 m resolution satellite images. In the simulation scheme, the materials are modeled as dry granular solids, and they travel down from the slopes and are deposited at the valley bottom. The spatial distributions of the debris materials are investigated in terms of location, volume and thickness. Simulation results show good agreement with post-disaster satellite images and field observation data. Additionally, the effect of the spatial distributions of the debris materials on subsequent debris flows is also evaluated. It is found that the spatial distributions of the debris materials strongly influence affected area, runout distance and flow discharge. This study might be useful in hazard assessments prior to debris flow hazards by investigating diverse scenarios in which the debris materials are unknown.

Comparative Evaluation of Sealing Ability of Three Newer Root Canal Obturating Materials Guttaflow, Resilon and Thermafil: An In Vitro Study

PubMed Central

H Bhandi, Shilpa; T S, Subhash

2013-01-01

Introduction: Microleakage continues to be a main reason for failure of root canal treatment where the challenge has been to achieve an adequate seal between the internal structure and the main obturating material. The objective of this study is to compare the sealing ability of 3 newer obturating materials GuttaFlow, Resilon/Epiphany system (RES) and Thermafil, using silver nitrate dye and observing under stereomicroscope. Methodology: Thirty single rooted teeth were divided into following groups. Group I : GuttaFlow ;Group II : Resilon /Epiphany sealer Group III : Thermafil with AH-Plus sealer. Teeth were decoronated and instrumented with profile rotary system and obturated with specified materials. Apical seal was determined by dye penetration method using silver nitrate. Then the specimens were transversely sectioned at each mm till 3 mm from the apex. Dye leakage was determined using stereomicroscope. Statistical analysis of the results was performed using Kruskall-Wallis test. Results: The results showed that Group II i.e., Resilon with Epiphany sealer showed the least amount of microleakage when compared to Group I i.e., GuttaFlow and Group III i.e., Thermafil with AH-plus sealer. Conclusion: Based on the results of this study it can be concluded that RES had higher sealing ability followed by Thermafil and GuttaFlow in vitro but further studies have to be carried out to make a direct correlation between these results and invivo situation. How to cite this article: Bhandi S H, Subhash T S. Comparative Evaluation of Sealing Ability of Three Newer Root Canal Obturating Materials Guttaflow, Resilon and Thermafil: An In Vitro Study. J Int Oral Health 2013; 5(1):54-65. PMID:24155579

The influence of resource strategies on childhood phthalate exposure--the role of REACH in a zero waste society.

PubMed

Lee, Jihyun; Pedersen, Anders Branth; Thomsen, Marianne

2014-12-01

The present study aims to investigate how resource strategies, which intend to reduce waste and increase recycling, influence on human exposure to hazardous chemicals from material recycling. In order to examine the flows of hazardous chemicals in recycled material, a mass flow analysis of plastics and paper at European level, including the flow of phthalates, i.e. di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), and benzyl-butyl phthalate (BBP), has been performed. The result for the year 2012 shows that 26% of plastic wastes and 60% of paper consumed in Europe were recycled. This corresponds to the finding that approximately 4% of DEHP and BBP and 18% of DBP annual demands in Europe as raw material re-enter the product cycle with recycled plastics and paper. To examine the potential contribution of the phthalate exposure through recycled plastics and paper, a case study assessing the childhood exposures to phthalates from foods packed in recycled paper and plastics has been performed for 2-year-old children in Denmark. The result verifies that an increase in recycled paperboard and PET bottles in food packaging material causes a significant increase in childhood exposure to DBP corresponding to an additional exposure of 0.116-0.355 μg/kg bw/day; up to 18% of the total DBP exposure in Danish 2-year-olds. While most of the DEHP exposure can be explained, more than 50% of DBP and 70% of BBP exposure sources still remain to be identified. Finally, a conceptual framework for a circular economy based on sustainable and clean resource flows is proposed in order to increase material recycling without increasing adverse health effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nuclear energy in Europe: uranium flow modeling and fuel cycle scenario trade-offs from a sustainability perspective.

PubMed

Tendall, Danielle M; Binder, Claudia R

2011-03-15

The European nuclear fuel cycle (covering the EU-27, Switzerland and Ukraine) was modeled using material flow analysis (MFA).The analysis was based on publicly available data from nuclear energy agencies and industries, national trade offices, and nongovernmental organizations. Military uranium was not considered due to lack of accessible data. Nuclear fuel cycle scenarios varying spent fuel reprocessing, depleted uranium re-enrichment, enrichment assays, and use of fast neutron reactors, were established. They were then assessed according to environmental, economic and social criteria such as resource depletion, waste production, chemical and radiation emissions, costs, and proliferation risks. The most preferable scenario in the short term is a combination of reduced tails assay and enrichment grade, allowing a 17.9% reduction of uranium demand without significantly increasing environmental, economic, or social risks. In the long term, fast reactors could theoretically achieve a 99.4% decrease in uranium demand and nuclear waste production. However, this involves important costs and proliferation risks. Increasing material efficiency is not systematically correlated with the reduction of other risks. This suggests that an overall optimization of the nuclear fuel cycle is difficult to obtain. Therefore, criteria must be weighted according to stakeholder interests in order to determine the most sustainable solution. This paper models the flows of uranium and associated materials in Europe, and provides a decision support tool for identifying the trade-offs of the alternative nuclear fuel cycles considered.

Radiopacity of flowable composite by a digital technique.

PubMed

Dukić, W; Delija, B; Lešić, S; Dubravica, I; Derossi, D

2013-01-01

The aim of this in vitro study was to evaluate the radiopacity of 19 current dental flowable composite materials by a digital technique. Digital radiographs were obtained with a CCD sensor using an aluminum step wedge, a 1-mm-thick tooth slice, and a 1-mm-thick flowable composite specimen using five different combinations of exposure and voltage. The radiopacity in pixels was determined using Digora 2.6. software. The equivalent thickness of aluminum for each material was then calculated based on the calibration curve. All of the tested flowable composite materials had higher radiopacities than that of dentin, but in almost every combination of exposure and voltage, there were some composite materials that exhibited radiopacities equal to or slightly greater than enamel p>α; α=0.01). Of the flowable composite materials tested, 37% showed lower radiopacities than enamel, and 21% of the tested materials had higher radiopacities than the 3-mm aluminum equivalent. The highest radiopacity at all exposure values was produced by the Majesty Flow and Charisma Opal Flow materials, which had radiopacities almost twice that of enamel. Flowable composite materials should have radiopacities greater than that of enamel (ISO 4049), an important consideration for the introduction of new materials to the market. The digital radiopacity analysis techniques used in this study provide an easy, reliable, rapid, and precise method to characterize radiopacity of dental flowable composite materials.

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.

Quasi-steady Bingham plastic analysis of an electrorheological flow mode bypass damper with piston bleed

NASA Astrophysics Data System (ADS)

Lindler, Jason; Wereley, Norman M.

2003-06-01

We present an improved experimental validation of our nonlinear quasi-steady electrorheological (ER) and magnetorheological damper analysis, using an idealized Bingham plastic shear flow mechanism, for the flow mode of damper operation with leakage effect. To validate the model, a double-acting ER valve or bypass damper was designed and fabricated. Both the hydraulic cylinder and the bypass duct have cylindrical geometry, and damping forces are developed in the annular bypass via Poiseuille flow. The ER fluid damper contains a controlled amount of leakage around the piston head. The leakage allows ER fluid to flow from one side of the piston head to the opposite side without passing through the ER bypass. For this flow mode damper, the damping coefficient, defined as the ratio of equivalent viscous damping of the Bingham plastic material, Ceq, to the Newtonian viscous damping, C, is a function of the non-dimensional plug thickness only. The damper was tested for varying conditions of applied electric field and frequency using a mechanical damper dynamometer. In this analysis, the leakage damping coefficient with incorporated leakage effects, predict the amount of energy dissipated for a complete cycle of the piston rod. Measured force verses displacement cycles for multiple frequencies and electric fields validate the ability of the non-dimensional groups and the leakage damping coefficient to predict the damping levels for an ER bypass damper with leakage. Based on the experimental validation of the model using these data, the Bingham plastic analysis is shown to be an effective tool for the analysis-based design of double-acting ER bypass dampers.

On the Doppler Velocity of Emission Line Profiles Formed in the "Coronal Contraflow" that Is the Chromosphere-Corona Mass Cycle

NASA Astrophysics Data System (ADS)

McIntosh, Scott W.; Tian, Hui; Sechler, Marybeth; De Pontieu, Bart

2012-04-01

This analysis begins to explore the complex chromosphere-corona mass cycle using a blend of imaging and spectroscopic diagnostics. Single Gaussian fits (SGFs) to hot emission line profiles (formed above 1 MK) at the base of coronal loop structures indicate material blueshifts of 5-10 km s-1, while cool emission line profiles (formed below 1 MK) yield redshifts of a similar magnitude—indicating, to zeroth order, that a temperature-dependent bifurcating flow exists on coronal structures. Image sequences of the same region reveal weakly emitting upward propagating disturbances in both hot and cool emission with apparent speeds of 50-150 km s-1. Spectroscopic observations indicate that these propagating disturbances produce a weak emission component in the blue wing at commensurate speed, but that they contribute only a few percent to the (ensemble) emission line profile in a single spatio-temporal resolution element. Subsequent analysis of imaging data shows material "draining" slowly (~10 km s-1) out of the corona, but only in the cooler passbands. We interpret the draining as the return flow of coronal material at the end of the complex chromosphere-corona mass cycle. Further, we suggest that the efficient radiative cooling of the draining material produces a significant contribution to the red wing of cool emission lines that is ultimately responsible for their systematic redshift as derived from an SGF when compared to those formed in hotter (conductively dominated) domains. The presence of counterstreaming flows complicates the line profiles, their interpretation, and asymmetry diagnoses, but allows a different physical picture of the lower corona to develop.

A CFD study of Screw Compressor Motor Cooling Analysis

NASA Astrophysics Data System (ADS)

Branch, S.

2017-08-01

Screw compressors use electric motors to drive the male screw rotor. They are cooled by the suction refrigerant vapor that flows around the motor. The thermal conditions of the motor can dramatically influence the performance and reliability of the compressor. The more optimized this flow path is, the better the motor performance. For that reason it is important to understand the flow characteristics around the motor and the motor temperatures. Computational fluid dynamics (CFD) can be used to provide a detailed analysis of the refrigerant’s flow behavior and motor temperatures to identify the undesirable hot spots in the motor. CFD analysis can be used further to optimize the flow path and determine the reduction of hot spots and cooling effect. This study compares the CFD solutions of a motor cooling model to a motor installed with thermocouples measured in the lab. The compressor considered for this study is an R134a screw compressor. The CFD simulation of the motor consists of a detailed breakdown of the stator and rotor components. Orthotropic thermal conductivity material properties are used to represent the simplified motor geometry. In addition, the analysis includes the motor casings of the compressor to draw heat away from the motor by conduction. The study will look at different operating conditions and motor speeds. Finally, the CFD study will investigate the predicted motor temperature change by varying the vapor mass flow rates and motor speed. Recommendations for CFD modeling of such intricate heat transfer phenomenon have thus been proposed.

Two-dimensional Mathematical Model of Oil-bearing Materials in Extrusion-type Transportation over Rectangular Screw Core

NASA Astrophysics Data System (ADS)

Gukasyan, A. V.; Koshevoy, E. P.; Kosachev, V. S.

2018-05-01

A comparative analysis of alternative models for plastic flow in extrusive transportation of oil-bearing materials was conducted; the research was directed at determining the function describing the screw core throughput capacity of the press (extruder). Transition from a one-dimensional model to a two-dimensional model significantly improves the mathematical model and allows using two-dimensional rheological models determining the throughput of the screw core.

Manufacturing Technology Support (MATES). Task Order 0021: Air Force Technology and Industrial Base Research and Analysis, Subtask Order 06: Direct Digital Manufacturing

DTIC Science & Technology

2011-08-01

industries and key players providing equipment include Flow and OMAX. The decision tree for waterjet machining is shown in Figure 28. Figure 28...about the melt pool. Process parameters including powder flow , laser power, and scan speed are adjusted accordingly • Multiple materials o BD...project.eu.com/home/home_page_static.jsp o Working with multiple partners; one is Cochlear . Using LMD or SLM to fabricate cochlear implants with 10

A Regional Guidebook for Conducting Functional Assessments of Wetland and Riparian Forests in the Ouachita Mountains and Crowley’s Ridge Regions of Arkansas

DTIC Science & Technology

2006-12-01

92–101. Bovee, K . D . 1982. A guide to stream habitat analysis using the in stream flow incremental methodology. Instream Flow Information Paper No...Thames. 1991. Hydrology and the management of watersheds . Iowa State University Press, Ames, IA. Brown, J. K . 1974. Handbook for inventorying downed...woody material. General Technical Report INT-16, U.S. Department of Agriculture, Forest Service. Brown, J. K ., R. D . Oberheu, and C. M. Johnston

Architected squirt-flow materials for energy dissipation

NASA Astrophysics Data System (ADS)

Cohen, Tal; Kurzeja, Patrick; Bertoldi, Katia

2017-12-01

In the present study we explore material architectures that lead to enhanced dissipation properties by taking advantage of squirt-flow - a local flow mechanism triggered by heterogeneities at the pore level. While squirt-flow is a known dominant source of dissipation and seismic attenuation in fluid saturated geological materials, we study its untapped potential to be incorporated in highly deformable elastic materials with embedded fluid-filled cavities for future engineering applications. An analytical investigation, that isolates the squirt-flow mechanism from other potential dissipation mechanisms and considers an idealized setting, predicts high theoretical levels of dissipation achievable by squirt-flow and establishes a set of guidelines for optimal dissipation design. Particular architectures are then investigated via numerical simulations showing that a careful design of the internal voids can lead to an increase of dissipation levels by an order of magnitude, compared with equivalent homogeneous void distributions. Therefore, we suggest squirt-flow as a promising mechanism to be incorporated in future architected materials to effectively and reversibly dissipate energy.

Using the Richtmyer-Meshkov flow to infer the strength of LY-12 aluminum at extreme conditions

NASA Astrophysics Data System (ADS)

Yin, Jianwei; Pan, Hao; Peng, Jiangxiang; Wu, Zihui; Yu, Yuying; Hu, Xiaomian

2017-06-01

An improved analytical model of the Richtmyer-Meshkov (RM) flow in the elastoplastic materials is presented in this paper. This model describes the stabilization by yield strength (Y) effect on the RM flow in solids and linear relationships between initial configurations of perturbation and the growth. Then we make use of the model to analysis the explosion driven RM flow experiments with solid LY12 and test our model by comparing the predicted Y of existing strength models. Finally, we perform a plate impact experiment with solid LY12 aluminium alloy to validate our model and infer Y is about 1.23 GPa for a 28 GPa shock and a strain rate of 7.5 ×106 .

Improvement and analysis of the hydrogen-cerium redox flow cell

NASA Astrophysics Data System (ADS)

Tucker, Michael C.; Weiss, Alexandra; Weber, Adam Z.

2016-09-01

The H2-Ce redox flow cell is optimized using commercially-available cell materials. Cell performance is found to be sensitive to the upper charge cutoff voltage, membrane boiling pretreatment, methanesulfonic-acid concentration, (+) electrode surface area and flow pattern, and operating temperature. Performance is relatively insensitive to membrane thickness, Cerium concentration, and all features of the (-) electrode including hydrogen flow. Cell performance appears to be limited by mass transport and kinetics in the cerium (+) electrode. Maximum discharge power of 895 mW cm-2 was observed at 60 °C; an energy efficiency of 90% was achieved at 50 °C. The H2-Ce cell is promising for energy storage assuming one can optimize Ce reaction kinetics and electrolyte.

WASTE TIRES ON THE ISLAND OF DOMINICA: SURVEY AND SOLUTIONS

EPA Science Inventory

Phase I of LFL-Dominica was highly successful, resulting in a completed national tire inventory and Material Flow Analysis, a waste tire feasibility study, expansion of the project to include organic gardens, identification and screening of three sites for potential LFL implem...

Determination of densified biomass mass properties using 3D laser scanning and image analysis

USDA-ARS?s Scientific Manuscript database

Biomass densification is viewed as the indispensable feedstock preprocessing operation for efficient transport, storage, material flow through machines, and handling activities. Accurate mass properties of densified biomass such as surface area, volume, and envelope density form fundamental data for...

The influence of slope-angle ratio on the dynamics of granular flows: insights from laboratory experiments

NASA Astrophysics Data System (ADS)

Sulpizio, R.; Castioni, D.; Rodriguez-Sedano, L. A.; Sarocchi, D.; Lucchi, F.

2016-11-01

Laboratory experiments on granular flows using natural material were carried out in order to investigate the behaviour of granular flows passing over a break in slope. Sensors in the depositional area recorded the flow kinematics, while video footage permitted reconstruction of the deposit formation, which allowed investigation of the deposit shape as a function of the change in slope. We defined the slope-angle ratio as the proportion between slope angle in the depositional area and that of the channel. When the granular flow encounters the break in slope part of the flow front forms a bouncing clast zone due to elastic impact with the expansion box floor. During this process, part of the kinetic energy of the dense granular flow is transferred to elutriating fine ash, which subsequently forms turbulent ash cloud accompanying the granular flow until it comes to rest. Morphometric analysis of the deposits shows that they are all elliptical, with an almost constant minor axis and a variable major axis. The almost constant value of the minor axis relates to the spreading angle of flow at the end of the channel, which resembles the basal friction angle of the material. The variation of the major axis is interpreted to relate to the effect of competing inertial and frictional forces. This effect also reflects the partitioning of centripetal and tangential velocities, which changes as the flow passes over the break in slope. After normalization, morphometric data provided empirical relationships that highlight the dependence of runout from the product of slope-angle ratio and the difference in height between granular material release and deposit. The empirical relationships were tested against the runouts of hot avalanches formed during the 1944 ad eruption at Vesuvius, with differences among actual and calculated values are between 1.7 and 15 %. Velocity measurements of laboratory granular flows record deceleration paths at different breaks in slope. When normalized, the velocity data show third-order polynomial fit, highlighting a complex behaviour involving interplay between inertial and frictional forces. The theoretical velocity decays were tested against the data published for volcaniclastic debris flows of the 5-6 May 1998 event in the Sarno area. The comparison is very good for non-channelized debris flows, with significant differences between actual and calculated velocities for the channelized debris flows.

Bearing tester data compilation, analysis, and reporting and bearing math modeling

NASA Technical Reports Server (NTRS)

1986-01-01

A test condition data base was developed for the Bearing and Seal Materials Tester (BSMT) program which permits rapid retrieval of test data for trend analysis and evaluation. A model was developed for the Space shuttle Main Engine (SSME) Liquid Oxygen (LOX) turbopump shaft/bearing system. The model was used to perform parametric analyses to determine the sensitivity of bearing operating characteristics and temperatures to variations in: axial preload, contact friction, coolant flow and subcooling, heat transfer coefficients, outer race misalignments, and outer race to isolator clearances. The bearing program ADORE (Advanced Dynamics of Rolling Elements) was installed on the UNIVAC 1100/80 computer system and is operational. ADORE is an advanced FORTRAN computer program for the real time simulation of the dynamic performance of rolling bearings. A model of the 57 mm turbine-end bearing is currently being checked out. Analyses were conducted to estimate flow work energy for several flow diverter configurations and coolant flow rates for the LOX BSMT.

Methods of chemically converting first materials to second materials utilizing hybrid-plasma systems

DOEpatents

Kong, Peter C.; Grandy, Jon D.

2002-01-01

In one aspect, the invention encompasses a method of chemically converting a first material to a second material. A first plasma and a second plasma are formed, and the first plasma is in fluid communication with the second plasma. The second plasma comprises activated hydrogen and oxygen, and is formed from a water vapor. A first material is flowed into the first plasma to at least partially ionize at least a portion of the first material. The at least partially ionized first material is flowed into the second plasma to react at least some components of the first material with at least one of the activated hydrogen and activated oxygen. Such converts at least some of the first material to a second material. In another aspect, the invention encompasses a method of forming a synthetic gas by flowing a hydrocarbon-containing material into a hybrid-plasma system. In yet another aspect, the invention encompasses a method of degrading a hydrocarbon-containing material by flowing such material into a hybrid-plasma system. In yet another aspect, the invention encompasses a method of releasing an inorganic component of a complex comprising the inorganic component and an other component, wherein the complex is flowed through a hybrid-plasma system.

Flow accelerated corrosion of carbon steel feeder pipes from pressurized heavy water reactors

NASA Astrophysics Data System (ADS)

Singh, J. L.; Kumar, Umesh; Kumawat, N.; Kumar, Sunil; Kain, Vivekanand; Anantharaman, S.; Sinha, A. K.

2012-10-01

Detailed investigation of a number of feeder pipes received from Rajasthan Atomic Power Station Unit 2 (RAPS#2) after en-masse feeder pipe replacement after 15.67 Effective Full Power Years (EFPYs) was carried out. Investigations included ultrasonic thickness measurement by ultrasonic testing, optical microscopy, scanning electron microscopy, chemical analysis and X-ray Diffraction (XRD). Results showed that maximum thickness reduction of the feeder had occurred downstream and close to the weld in 32 NB (1.25″/32.75 mm ID) elbows. Rate of Flow Accelerated Corrosion (FAC) was measured to be higher in the lower diameter feeder pipes due to high flow velocity and turbulence. Weld regions had thinned to a lower extent than the parent material due to higher chromium content in the weld. A weld protrusion has been shown to add to the thinning due to FAC and lead to faster thinning rate at localized regions. Surface morphology of inner surface of feeder had shown different size scallop pattern over the weld and parent material. Inter-granular cracks were also observed along the weld fusion line and in the parent material in 32 NB outlet feeder elbow.

Modeling granular material flows: The angle of repose, fluidization and the cliff collapse problem

NASA Astrophysics Data System (ADS)

Holsapple, Keith A.

2013-07-01

I discuss theories of granular material flows, with application to granular flows on the earth and planets. There are two goals. First, there is a lingering belief of some that the standard continuum plasticity Mohr-Coulomb and/or Drucker-Prager models are not adequate for many large-scale granular flow problems. The stated reason for those beliefs is the fact that the final slopes of the run-outs in collapse, landslide problems, and large-scale cratering are well below the angle of repose of the material. That observation, combined with the supposition that in those models flow cannot occur with slopes less than the angle of repose, has led to a number of researchers suggesting a need for lubrication or fluidization mechanisms and modeling. That issue is investigated in detail and shown to be false. A complete analysis of slope failures according to the Mohr-Coulomb model is presented, with special attention to the relations between the angle of repose and slope failures. It is shown that slope failure can occur for slope angles both larger than and smaller than the angle of repose. Second, to study the details of landslide run-outs, finite-difference continuum code simulations of the prototypical cliff collapse problem, using the classical plasticity models, are presented, analyzed and compared to experiments. Although devoid of any additional fluidization models, those simulations match experiments in the literature extremely well. The dynamics of this problem introduces additional important features relating to the run-out and final slope angles. The vertical free surface begins to fall at the initial 90° and flow continues to a final slope less than 10°. The detail in the calculation is examined to show why flow persists at slope angles that appear to be less than the angle of repose. The motions include regions of solid-like, fluid-like, and gas-like flows without invoking any additional models.

Impact of the 2008 Wenchuan earthquake in China on subsequent long-term debris flow activities in the epicentral area

NASA Astrophysics Data System (ADS)

Zhang, S.; Zhang, L. M.

2017-01-01

The 2008 Wenchuan earthquake triggered the largest number of landslides among the recent strong earthquake events around the world. The loose landslide materials were retained on steep terrains and deep gullies. In the period from 2008 to 2015, numerous debris flows occurred during rainstorms along the Provincial Road 303 (PR303) near the epicentre of the earthquake, causing serious damage to the reconstructed highway. Approximately 5.24 × 106 m3 of debris-flow sediment was deposited shortly after the earthquake. This paper evaluates the evolution of the debris flows that occurred after the Wenchuan earthquake, which helps understand long-term landscape evolution and cascading effects in regions impacted by mega earthquakes. With the aid of a GIS platform combined with field investigations, we continuously tracked movements of the loose deposit materials in all the debris flow gullies along an 18 km reach of PR303 and the characteristics of the regional debris flows during several storms in the past seven years. This paper presents five important aspects of the evolution of debris flows: (1) supply of debris flow materials; (2) triggering rainfall; (3) initiation mechanisms and types of debris flows; (4) runout characteristics; and (5) elevated riverbed due to the deposited materials from the debris flows. The hillslope soil deposits gradually evolved into channel deposits and the solid materials in the channels moved towards the ravine mouth. Accordingly, channelized debris flows became dominant gradually. Due to the decreasing source material volume and changes in debris flow characteristics, the triggering rainfall tends to increase from 30 mm h- 1 in 2008 to 64 mm h- 1 in 2013, and the runout distance tends to decrease over time. The runout materials blocked the river and elevated the riverbed by at least 30 m in parts of the study area. The changes in the post-seismic debris flow activity can be categorized into three stages, i.e., active, unstable, and recession.

Electronic waste management approaches: An overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiddee, Peeranart; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Mawson Lakes Campus, Adelaide, SA 5095; Naidu, Ravi, E-mail: ravi.naidu@crccare.com

2013-05-15

Highlights: ► Human toxicity of hazardous substances in e-waste. ► Environmental impacts of e-waste from disposal processes. ► Life Cycle Assessment (LCA), Material Flow Analysis (MFA), Multi Criteria Analysis (MCA) and Extended Producer Responsibility (EPR) to and solve e-waste problems. ► Key issues relating to tools managing e-waste for sustainable e-waste management. - Abstract: Electronic waste (e-waste) is one of the fastest-growing pollution problems worldwide given the presence if a variety of toxic substances which can contaminate the environment and threaten human health, if disposal protocols are not meticulously managed. This paper presents an overview of toxic substances present inmore » e-waste, their potential environmental and human health impacts together with management strategies currently being used in certain countries. Several tools including Life Cycle Assessment (LCA), Material Flow Analysis (MFA), Multi Criteria Analysis (MCA) and Extended Producer Responsibility (EPR) have been developed to manage e-wastes especially in developed countries. The key to success in terms of e-waste management is to develop eco-design devices, properly collect e-waste, recover and recycle material by safe methods, dispose of e-waste by suitable techniques, forbid the transfer of used electronic devices to developing countries, and raise awareness of the impact of e-waste. No single tool is adequate but together they can complement each other to solve this issue. A national scheme such as EPR is a good policy in solving the growing e-waste problems.« less

Structural studies on carbon materials for advanced space technology. Part 1: Structure and oxidation behavior of some carbon/carbon composite materials

NASA Technical Reports Server (NTRS)

Fischbach, D. B.; Uptegrove, D. R.; Srinivasagopalan, S.

1974-01-01

The microstructure and some microstructural effects of oxidation have been investigated for laminar carbon fiber cloth/cloth binder matrix composite materials. It was found that cloth wave is important in determining the macrostructure of the composites X-ray diffraction analysis showed that the composites were more graphitic than the constituent fiber phases, indicating a graphitic binder matrix phase. Various tests which were conducted to investigate specific properties of the material are described. It was learned that under the moderate temperature and oxidant flow conditions studied, C-700, 730 materials exhibit superior oxidation resistance primarily because of the inhibiting influence of the graphitized binder matrix.

Analysis of the flow property of aluminum alloy AA6016 based on the fracture morphology using the hydroforming technology

NASA Astrophysics Data System (ADS)

Lang, Lihui; Zhang, Quanda; Sun, Zhiying; Wang, Yao

2017-09-01

In this paper, the hydraulic bulging experiments were respectively carried out using AA6016-T4 aluminum alloy and AA6016-O aluminum alloy, and the deformation properties and fracture mechanism of aluminum alloy under the conditions of thermal and hydraulic were analyzed. Firstly, the aluminum alloy AA6016 was dealt with two kinds of heat treatment systems such as solid solution heat treatment adding natural ageing and full annealing, then the aluminum alloy such as AA6016-T4 and AA6016-O were obtained. In the same working environment, the two kinds of materials were used in the process of hydraulic bulging experiments, according to the observation and measurement of the deformation sizes of grid circles and material thicknesses near the fracture region, the flow properties and development trend of fracture defect of the materials were analyzed comprehensively from the perspective of qualitative analysis and quantitative analysis; Secondly, the two kinds of materials were sampled in different regions of the fracture area and the microstructure morphology of the fracture was observed by the scanning electron microscope (SEM). The influence laws of the heat treatment systems on the fracture defect of the aluminum alloy under the condition of the liquid pressure were studied preliminarily by observing the distribution characteristics of the fracture microstructure morphology of dimple. At the same time, the experimental research on the ordinary stamping forming process of AA6016-O was carried out and the influence law of different forming process on the fracture defect of the aluminum alloy material was studied by observing the distribution of the fracture microstructure morphology; Finally, the development process of the fracture defect of aluminum alloy sheet was described theoretically from the view of the stress state.

Flow cytometric analysis of microbial contamination in food industry technological lines--initial study.

PubMed

Józwa, Wojciech; Czaczyk, Katarzyna

2012-04-02

Flow cytometry constitutes an alternative for traditional methods of microorganisms identification and analysis, including methods requiring cultivation step. It enables the detection of pathogens and other microorganisms contaminants without the need to culture microbial cells meaning that the sample (water, waste or food e.g. milk, wine, beer) may be analysed directly. This leads to a significant reduction of time required for analysis allowing monitoring of production processes and immediate reaction in case of contamination or any disruption occurs. Apart from the analysis of raw materials or products on different stages of manufacturing process, the flow cytometry seems to constitute an ideal tool for the assessment of microbial contamination on the surface of technological lines. In the present work samples comprising smears from 3 different surfaces of technological lines from fruit and vegetable processing company from Greater Poland were analysed directly with flow cytometer. The measured parameters were forward and side scatter of laser light signals allowing the estimation of microbial cell contents in each sample. Flow cytometric analysis of the surface of food industry production lines enable the preliminary evaluation of microbial contamination within few minutes from the moment of sample arrival without the need of sample pretreatment. The presented method of fl ow cytometric initial evaluation of microbial state of food industry technological lines demonstrated its potential for developing a robust, routine method for the rapid and labor-saving detection of microbial contamination in food industry.

Calibration of numerical models for small debris flows in Yosemite Valley, California, USA

USGS Publications Warehouse

Bertolo, P.; Wieczorek, G.F.

2005-01-01

This study compares documented debris flow runout distances with numerical simulations in the Yosemite Valley of California, USA, where about 15% of historical events of slope instability can be classified as debris flows and debris slides (Wieczorek and Snyder, 2004). To model debris flows in the Yosemite Valley, we selected six streams with evidence of historical debris flows; three of the debris flow deposits have single channels, and the other three split their pattern in the fan area into two or more channels. From field observations all of the debris flows involved coarse material, with only very small clay content. We applied the one dimensional DAN (Dynamic ANalysis) model (Hungr, 1995) and the two-dimensional FLO2D model (O'Brien et al., 1993) to predict and compare the runout distance and the velocity of the debris flows observed in the study area. As a first step, we calibrated the parameters for the two softwares through the back analysis of three debris- flows channels using a trial-and-error procedure starting with values suggested in the literature. In the second step we applied the selected values to the other channels, in order to evaluate their predictive capabilities. After parameter calibration using three debris flows we obtained results similar to field observations We also obtained a good agreement between the two models for velocities. Both models are strongly influenced by topography: we used the 30 m cell size DTM available for the study area, that is probably not accurate enough for a highly detailed analysis, but it can be sufficient for a first screening. European Geosciences Union ?? 2005 Author(s). This work is licensed under a Creative Commons License.

Disposable and removable nucleic acid extraction and purification cartridges for automated flow-through systems

DOEpatents

Regan, John Frederick

2014-09-09

Removable cartridges are used on automated flow-through systems for the purpose of extracting and purifying genetic material from complex matrices. Different types of cartridges are paired with specific automated protocols to concentrate, extract, and purifying pathogenic or human genetic material. Their flow-through nature allows large quantities sample to be processed. Matrices may be filtered using size exclusion and/or affinity filters to concentrate the pathogen of interest. Lysed material is ultimately passed through a filter to remove the insoluble material before the soluble genetic material is delivered past a silica-like membrane that binds the genetic material, where it is washed, dried, and eluted. Cartridges are inserted into the housing areas of flow-through automated instruments, which are equipped with sensors to ensure proper placement and usage of the cartridges. Properly inserted cartridges create fluid- and air-tight seals with the flow lines of an automated instrument.

Antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles.

PubMed

Ginjupalli, Kishore; Alla, Rama Krishna; Tellapragada, Chaitanya; Gupta, Lokendra; Upadhya Perampalli, Nagaraja

2016-06-01

Conventional spray and the immersion disinfection of irreversible hydrocolloid impression materials may lead to dimensional changes. The purpose of this in vitro study was to investigate the antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles. The antimicrobial activity and properties of 2 commercially available irreversible hydrocolloid impression materials were evaluated after incorporating varying concentrations of silver nanoparticles. Antimicrobial activity was determined using the disk diffusion method. The gel strength, permanent deformation, flow, and gelation time were measured according to American Dental Association specification #18. Analysis of variance was used to identify the significant differences within and across the groups (α=.05). Adding silver nanoparticles to irreversible hydrocolloid impression materials resulted in superior antimicrobial activity without adversely affecting their properties. Adding silver nanoparticles to Zelgan significantly increased the gel strength compared with the control group, except at 5 wt%. However, the gel strength of Tropicalgin was unaffected except at 5 wt%. An increase in the permanent deformation was found with the incorporation of silver nanoparticles in both Zelgan and Tropicalgin. The flow of Zelgan increased with the incorporation of silver nanoparticles, whereas a decrease in the flow of Tropicalgin was observed at 1 wt% and 2 wt%. An increase in the gelation time of both Zelgan and Tropicalgin was observed with the incorporation of silver nanoparticles. Based on this in vitro study, silver nanoparticles can be incorporated into irreversible hydrocolloid impression materials as antimicrobial agents without adversely affecting their properties. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Development of the technology for the fabrication of reliable laminar flow control panels

NASA Technical Reports Server (NTRS)

Weiss, D. D.; Lindh, D. V.

1977-01-01

Various configurations of porous, perforated and slotted materials were flow tested to determine if they would meet the LFC surface smoothness and flow requirements. The candidate materials were then tested for susceptibility to clogging and for resistance to corrosion. Of the materials tested, perforated titanium, porous polyimide, and slotted assemblies demonstrated a much greater resistance to clogging than other porous materials.

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 to fit experimental data such as temperature profiles, torque and tool forces. General aspects of the experimentally visualized material flow pattern are confirmed by the 3-D model.

Flutter Phenomenon in Flow Driven Energy Harvester–A Unified Theoretical Model for “Stiff” and “Flexible” Materials

PubMed Central

Chen, Yu; Mu, Xiaojing; Wang, Tao; Ren, Weiwei; Yang, Ya; Wang, Zhong Lin; Sun, Chengliang; Gu, Alex Yuandong

2016-01-01

Here, we report a stable and predictable aero-elastic motion in the flow-driven energy harvester, which is different from flapping and vortex-induced-vibration (VIV). A unified theoretical frame work that describes the flutter phenomenon observed in both “stiff” and “flexible” materials for flow driven energy harvester was presented in this work. We prove flutter in both types of materials is the results of the coupled effects of torsional and bending modes. Compared to “stiff” materials, which has a flow velocity-independent flutter frequency, flexible material presents a flutter frequency that almost linearly scales with the flow velocity. Specific to “flexible” materials, pre-stress modulates the frequency range in which flutter occurs. It is experimentally observed that a double-clamped “flexible” piezoelectric P(VDF-TrFE) thin belt, when driven into the flutter state, yields a 1,000 times increase in the output voltage compared to that of the non-fluttered state. At a fixed flow velocity, increase in pre-stress level of the P(VDF-TrFE) thin belt up-shifts the flutter frequency. In addition, this work allows the rational design of flexible piezoelectric devices, including flow-driven energy harvester, triboelectric energy harvester, and self-powered wireless flow speed sensor. PMID:27739484

A high-resolution Godunov method for compressible multi-material flow on overlapping grids

NASA Astrophysics Data System (ADS)

Banks, J. W.; Schwendeman, D. W.; Kapila, A. K.; Henshaw, W. D.

2007-04-01

A numerical method is described for inviscid, compressible, multi-material flow in two space dimensions. The flow is governed by the multi-material Euler equations with a general mixture equation of state. Composite overlapping grids are used to handle complex flow geometry and block-structured adaptive mesh refinement (AMR) is used to locally increase grid resolution near shocks and material interfaces. The discretization of the governing equations is based on a high-resolution Godunov method, but includes an energy correction designed to suppress numerical errors that develop near a material interface for standard, conservative shock-capturing schemes. The energy correction is constructed based on a uniform-pressure-velocity flow and is significant only near the captured interface. A variety of two-material flows are presented to verify the accuracy of the numerical approach and to illustrate its use. These flows assume an equation of state for the mixture based on the Jones-Wilkins-Lee (JWL) forms for the components. This equation of state includes a mixture of ideal gases as a special case. Flow problems considered include unsteady one-dimensional shock-interface collision, steady interaction of a planar interface and an oblique shock, planar shock interaction with a collection of gas-filled cylindrical inhomogeneities, and the impulsive motion of the two-component mixture in a rigid cylindrical vessel.

Flutter Phenomenon in Flow Driven Energy Harvester-A Unified Theoretical Model for "Stiff" and "Flexible" Materials.

PubMed

Chen, Yu; Mu, Xiaojing; Wang, Tao; Ren, Weiwei; Yang, Ya; Wang, Zhong Lin; Sun, Chengliang; Gu, Alex Yuandong

2016-10-14

Here, we report a stable and predictable aero-elastic motion in the flow-driven energy harvester, which is different from flapping and vortex-induced-vibration (VIV). A unified theoretical frame work that describes the flutter phenomenon observed in both "stiff" and "flexible" materials for flow driven energy harvester was presented in this work. We prove flutter in both types of materials is the results of the coupled effects of torsional and bending modes. Compared to "stiff" materials, which has a flow velocity-independent flutter frequency, flexible material presents a flutter frequency that almost linearly scales with the flow velocity. Specific to "flexible" materials, pre-stress modulates the frequency range in which flutter occurs. It is experimentally observed that a double-clamped "flexible" piezoelectric P(VDF-TrFE) thin belt, when driven into the flutter state, yields a 1,000 times increase in the output voltage compared to that of the non-fluttered state. At a fixed flow velocity, increase in pre-stress level of the P(VDF-TrFE) thin belt up-shifts the flutter frequency. In addition, this work allows the rational design of flexible piezoelectric devices, including flow-driven energy harvester, triboelectric energy harvester, and self-powered wireless flow speed sensor.

Materials and energy flow in the life cycle of leather: a case study of Bangladesh

NASA Astrophysics Data System (ADS)

Chowdhury, Zia Uddin Md.; Ahmed, Tanvir; Hashem, Md. Abul

2018-05-01

This article presents the results of the materials and energy flow analysis for leather produced in Bangladesh and establishes an inventory for the life cycle assessment. Also, a comparison is made with the material and energy flow of the Indian leather. A cradle to gate analysis is performed for full-chrome leather (FCL), a representative leather article from an export-oriented industry in Bangladesh, taking into consideration the main processes associated with leather production and the corresponding materials and energy input. Data was collected on annual wet-salted rawhide consumption, water, and steam consumption, chemicals requirement, tannery solid waste generation, electricity, fuel oil use for the generator and steam boiler. Moreover, an analysis of the physical and chemical properties of wastewater emissions of the different leather unit processes was performed. The input and output profiles of the FCL were compared to those of an Indian leather. It was seen that FCL consumed water 2 times higher than the Indian leather while the electricity consumption of Indian leather was almost 2 times higher than its Bangladeshi counterpart. The Indian leather had significantly higher carbon footprint (in terms of CO2 equivalent emission) mainly because of the consumption of grid electricity that comes from coal-based power generation. Wastewater parameters such as chloride, Total Dissolved Solids (TDS) and Total Solids (TS) for the Indian leather are more than 4.5, 3 and 3 times higher respectively than that of corresponding emissions for the Bangladeshi FCL, which can be attributed to the higher use of inorganic salts in the process. Despite similar input of chromium compounds for both the leathers, the emission of total chromium was slightly higher in the case of Indian leather probably due to lower uptake of chromium by the substrate. Bangladeshi FCL used twice in the amount of (NH4)2SO4 than India, which may be responsible for the higher BOD load in the wastewater. It can also be seen that a significant amount of rawhide input is not converted into the usable leather as demonstrated by the high proportion of solid waste generation (70% and 55% for Bangladeshi FCL and Indian leather respectively). This study highlights that wide variations exist in the materials and energy flows from different tanneries. Understanding these variations is essential to pinpoint areas where resources can be used more efficiently and optimally in the leather manufacturing process.

Outlook of the world steel cycle based on the stock and flow dynamics.

PubMed

Hatayama, Hiroki; Daigo, Ichiro; Matsuno, Yasunari; Adachi, Yoshihiro

2010-08-15

We present a comprehensive analysis of steel use in the future compiled using dynamic material flow analysis (MFA). A dynamic MFA for 42 countries depicted the global in-use stock and flow up to the end of 2005. On the basis of the transition of steel stock for 2005, the growth of future steel stock was then estimated considering the economic growth for every country. Future steel demand was estimated using dynamic analysis under the new concept of "stocks drive flows". The significant results follow. World steel stock reached 12.7 billion t in 2005, and has doubled in the last 25 years. The world stock in 2005 mainly consisted of construction (60%) and vehicles (10%). Stock in these end uses will reach 55 billion t in 2050, driven by a 10-fold increase in Asia. Steel demand will reach 1.8 billion t in 2025, then slightly decrease, and rise again by replacement of buildings. The forecast of demand clearly represents the industrial shift; at first the increase is dominated by construction, and then, after 2025, demand for construction decreases and demand for vehicles increases instead. This study thus provides the dynamic mechanism of steel stock and flow toward the future, which contributes to the design of sustainable steel use.

Ill-posedness of Dynamic Equations of Compressible Granular Flow

NASA Astrophysics Data System (ADS)

Shearer, Michael; Gray, Nico

2017-11-01

We introduce models for 2-dimensional time-dependent compressible flow of granular materials and suspensions, based on the rheology of Pouliquen and Forterre. The models include density dependence through a constitutive equation in which the density or volume fraction of solid particles with material density ρ* is taken as a function of an inertial number I: ρ = ρ * Φ(I), in which Φ(I) is a decreasing function of I. This modelling has different implications from models relying on critical state soil mechanics, in which ρ is treated as a variable in the equations, contributing to a flow rule. The analysis of the system of equations builds on recent work of Barker et al in the incompressible case. The main result is the identification of a criterion for well-posedness of the equations. We additionally analyze a modification that applies to suspensions, for which the rheology takes a different form and the inertial number reflects the role of the fluid viscosity.

Present status of the liquid lithium target facility in the international fusion materials irradiation facility (IFMIF)

NASA Astrophysics Data System (ADS)

Nakamura, Hiroo; Riccardi, B.; Loginov, N.; Ara, K.; Burgazzi, L.; Cevolani, S.; Dell'Orco, G.; Fazio, C.; Giusti, D.; Horiike, H.; Ida, M.; Ise, H.; Kakui, H.; Matsui, H.; Micciche, G.; Muroga, T.; Nakamura, Hideo; Shimizu, K.; Sugimoto, M.; Suzuki, A.; Takeuchi, H.; Tanaka, S.; Yoneoka, T.

2004-08-01

During the three year key element technology phase of the International Fusion Materials Irradiation Facility (IFMIF) project, completed at the end of 2002, key technologies have been validated. In this paper, these results are summarized. A water jet experiment simulating Li flow validated stable flow up to 20 m/s with a double reducer nozzle. In addition, a small Li loop experiment validated stable Li flow up to 14 m/s. To control the nitrogen content in Li below 10 wppm will require surface area of a V-Ti alloy getter of 135 m 2. Conceptual designs of diagnostics have been carried out. Moreover, the concept of a remote handling system to replace the back wall based on `cut and reweld' and `bayonet' options has been established. Analysis by FMEA showed safe operation of the target system. Recent activities in the transition phase, started in 2003, and plan for the next phase are also described.

Tearing Instability of a Current Sheet Forming by Sheared Incompressible Flow

NASA Astrophysics Data System (ADS)

Tolman, Elizabeth; Loureiro, Nuno; Uzdensky, Dmitri

2017-10-01

Sweet-Parker current sheets are unstable to the tearing mode, suggesting they will not form in physical systems. Understanding magnetic reconnection thus requires study of the stability of a current sheet as it forms. Such formation can occur as a result of sheared, sub-Alfvénic incompressible flows into and along the sheet. This work presents an analysis of how tearing perturbations behave in a current sheet forming under the influence of such flows, beginning with a phase when the growth rate of the tearing mode is small and the behavior of perturbations is primarily governed by ideal MHD. Later, after the tearing growth rate becomes significant relative to the time scale of the driving flows, the flows cause a slight reduction in the tearing growth rate and wave vector of the dominant mode. Once the tearing mode enters the nonlinear regime, the flows accelerate the tearing growth slightly; during X-point collapse, the flows have negligible effect on the system behavior. This analysis allows greater understanding of reconnection in evolving systems and increases confidence in the application of tools developed in time-independent current sheets to changing current sheets. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship.

Method and apparatus for casting conductive and semi-conductive materials

DOEpatents

Ciszek, T.F.

1984-08-13

A method and apparatus is disclosed for casting conductive and semi-conductive materials. The apparatus includes a plurality of conductive members arranged to define a container-like area having a desired cross-sectional shape. A portion or all of the conductive or semi-conductive material which is to be cast is introduced into the container-like area. A means is provided for inducing the flow of an electrical current in each of the conductive members, which currents act collectively to induce a current flow in the material. The induced current flow through the conductive members is in a direction substantially opposite to the induced current flow in the material so that the material is repelled from the conductive members during the casting process.

Method and apparatus for casting conductive and semiconductive materials

DOEpatents

Ciszek, Theodore F.

1986-01-01

A method and apparatus is disclosed for casting conductive and semiconduce materials. The apparatus includes a plurality of conductive members arranged to define a container-like area having a desired cross-sectional shape. A portion or all of the conductive or semiconductive material which is to be cast is introduced into the container-like area. A means is provided for inducing the flow of an electrical current in each of the conductive members, which currents act collectively to induce a current flow in the material. The induced current flow through the conductive members is in a direction substantially opposite to the induced current flow in the material so that the material is repelled from the conductive members during the casting process.

The Pollution Detectives, Part III: Roadside Lead Pollution.

ERIC Educational Resources Information Center

Sanderson, Phil

1989-01-01

Described is a simple test tube method developed lead analysis of samples of roadside soil. The relationship between the results and the traffic flow indicate car exhausts are the major source of lead pollution. Materials and procedures are detailed. An example of results is provided. (Author/CW)

Contained radiological analytical chemistry module

DOEpatents

Barney, David M.

1989-01-01

A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

Contained radiological analytical chemistry module

DOEpatents

Barney, David M.

1990-01-01

A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

Computational and Experimental Fluid-Structure Interaction Analysis of a High-Lift Wing with a Slat-Cove Filler for Noise Reduction

NASA Technical Reports Server (NTRS)

Scholten, William D.; Patterson, Ryan D.; Hartl, Darren J.; Strganac, Thomas W.; Chapelon, Quentin H. C.; Turner, Travis

2017-01-01

Airframe noise is a significant component of overall noise produced by transport aircraft during landing and approach (low speed maneuvers). A significant source for this noise is the cove of the leading-edge slat. The slat-cove filler (SCF) has been shown to be effective at mitigating slat noise. The objective of this work is to understand the fluid-structure interaction (FSI) behavior of a superelastic shape memory alloy (SMA) SCF in flow using both computational and physical models of a high-lift wing. Initial understanding of flow around the SCF and wing is obtained using computational fluid dynamics (CFD) analysis at various angles of attack. A framework compatible with an SMA constitutive model (implemented as a user material subroutine) is used to perform FSI analysis for multiple flow and configuration cases. A scaled physical model of the high-lift wing is constructed and tested in the Texas A&M 3 ft-by-4-foot wind tunnel. Initial validation of both CFD and FSI analysis is conducted by comparing lift, drag and pressure distributions with experimental results.

Experimental Investigation of Material Flows Within FSWs Using 3D Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charles R. Tolle; Timothy A. White; Karen S. Miller

2008-06-01

There exists significant prior work using tracers or pre-placed hardened markers within friction stir welding (FSWing) to experimentally explore material flow within the FSW process. Our experiments replaced markers with a thin sheet of copper foil placed between the 6061 aluminum lap and butt joints that were then welded. The absorption characteristics of x-rays for copper and aluminum are significantly different allowing for non-destructive evaluation (NDE) methods such as x-ray computed tomography (CT) to be used to demonstrate the material movement within the weldment on a much larger scale than previously shown. 3D CT reconstruction of the copper components ofmore » the weldment allows for a unique view into the final turbulent state of the welding process as process parameters are varied. The x-ray CT data of a section of the weld region was collected using a cone-beam x-ray imaging system developed at the INL. Six-hundred projections were collected over 360-degrees using a 160-kVp Bremsstrahlung x-ray generator (25-micrometer focal spot) and amorphoussilicon x-ray detector. The region of the object that was imaged was about 3cm tall and 1.5cm x 1cm in cross section, and was imaged at a magnification of about 3.6x. The data were reconstructed on a 0.5x0.5x0.5 mm3 voxel grid. After reconstruction, the aluminum and copper could be easily discriminated using a gray level threshold allowing visualization of the copper components. Fractal analysis of the tomographic reconstructed material topology is investigated as a means to quantify macro level material flow based on process parameters. The results of multi-pass FSWs show increased refinement of the copper trace material. Implications of these techniques for quantifying process flow are discussed.« less

Computational Analysis of Arc-Jet Wedge Tests Including Ablation and Shape Change

NASA Technical Reports Server (NTRS)

Goekcen, Tahir; Chen, Yih-Kanq; Skokova, Kristina A.; Milos, Frank S.

2010-01-01

Coupled fluid-material response analyses of arc-jet wedge ablation tests conducted in a NASA Ames arc-jet facility are considered. These tests were conducted using blunt wedge models placed in a free jet downstream of the 6-inch diameter conical nozzle in the Ames 60-MW Interaction Heating Facility. The fluid analysis includes computational Navier-Stokes simulations of the nonequilibrium flowfield in the facility nozzle and test box as well as the flowfield over the models. The material response analysis includes simulation of two-dimensional surface ablation and internal heat conduction, thermal decomposition, and pyrolysis gas flow. For ablating test articles undergoing shape change, the material response and fluid analyses are coupled in order to calculate the time dependent surface heating and pressure distributions that result from shape change. The ablating material used in these arc-jet tests was Phenolic Impregnated Carbon Ablator. Effects of the test article shape change on fluid and material response simulations are demonstrated, and computational predictions of surface recession, shape change, and in-depth temperatures are compared with the experimental measurements.

More Analytical Tools for Fluids Management in Space

NASA Astrophysics Data System (ADS)

Weislogel, Mark

Continued advances during the 2000-2010 decade in the analysis of a class of capillary-driven flows relevant to materials processing and fluids management aboard spacecraft have been made. The class of flows addressed concern combined forced and spontaneous capillary flows in complex containers with interior edges. Such flows are commonplace in space-based fluid systems and arise from the particular container geometry and wetting properties of the system. Important applications for this work include low-g liquid fill and/or purge operations and passive fluid phase separation operations, where the container (i.e. fuel tank, water processer, etc.) geometry possesses interior edges, and where quantitative information of fluid location, transients, flow rates, and stability is critical. Examples include the storage and handling of liquid propellants and cryogens, water conditioning for life support, fluid phase-change thermal systems, materials processing in the liquid state, on-orbit biofluids processing, among others. For a growing number of important problems, closed-form expressions to transient three-dimensional flows are possible that, as design tools, replace difficult, time-consuming, and rarely performed numerical calculations. An overview of a selection of solutions in-hand is presented with example problems solved. NASA drop tower, low-g aircraft, and ISS flight ex-periment results are employed where practical to buttress the theoretical findings. The current review builds on a similar review presented at COSPAR, 2002, for the approximate decade 1990-2000.

Britle failure of non-Newtonian, floating, extensional flows

NASA Astrophysics Data System (ADS)

Sayag, Roiy; Worster, Michael

2011-11-01

Glacier ice is driven by gravity to flow from the land, where it is under shear, into the ocean, where it floats and extends. Owing to its non-Newtonian rheology, the ice can flow axisymmetrically over the bed but undergo brittle failure once it is floating on the ocean, as observed for example in crevassing of ice shelves. We model this coupled flow as an intrusion of a viscous gravity current into a denser ocean and study it both theoretically and experimentally. We have conducted laboratory experiments using a shear-thinning suspension that represents ice, and a denser inviscid fluid that represents an ocean. The non-Newtonian fluid was released at a constant flux through a cylindrical nozzle over a horizontal plane. The grounded, shear-dominated region of the flow was axisymmetric throughout the experiment, while past the transition line axisymmetry broke down into a seemingly ordered set of finger-like extensions (floating shelves) that demonstrated brittle behaviour. We have found that the width of the fingers as well as their radial extent increase with the flux. We attempt to explain these observations through a fingering instability that is driven by the dynamical differences between the two flow domains and by the material rheology, and we project that analysis to formulate a linkage between the material properties of ice and an upper bound on the width of ice shelves. NERC

Analysis and Modeling of Small Crack Detection in Pressurized Fuselages for Structural Health Monitoring Applications (Preprint)

DTIC Science & Technology

2012-07-01

airframe failures resulting in the total loss of the aircraft [ Parton and Morozov (1978); Piascik (1999)]. More recently, in April 1988, the Aloha...a material [ Parton and Morozov (1978)]. The size of the region covered by the plastic flow depends on the material properties and the loading...crack length due to uniaxial loads applied normal to the crack orientation. The Griffith-Orowan-Irwin concept [ Parton (1992)] establishes that the

Perspectives of advanced thermal management in solar thermochemical syngas production using a counter-flow solid-solid heat exchanger

NASA Astrophysics Data System (ADS)

Falter, Christoph; Sizmann, Andreas; Pitz-Paal, Robert

2017-06-01

A modular reactor model is presented for the description of solar thermochemical syngas production involving counter-flow heat exchangers that recuperate heat from the solid phase. The development of the model is described including heat diffusion within the reactive material as it travels through the heat exchanger, which was previously identified to be a possibly limiting factor in heat exchanger design. Heat transfer within the reactive medium is described by conduction and radiation, where the former is modeled with the three-resistor model and the latter with the Rosseland diffusion approximation. The applicability of the model is shown by the analysis of heat exchanger efficiency for different material thicknesses and porosities in a system with 8 chambers and oxidation and reduction temperatures of 1000 K and 1800 K, respectively. Heat exchanger efficiency is found to rise strongly for a reduction of material thickness, as the element mass is reduced and a larger part of the elements takes part in the heat exchange process. An increase of porosity enhances radiation heat exchange but deteriorates conduction. The overall heat exchange in the material is improved for high temperatures in the heat exchanger, as radiation dominates the energy transfer. The model is shown to be a valuable tool for the development and analysis of solar thermochemical reactor concepts involving heat exchange from the solid phase.

Analysis of potential debris flow source areas on Mount Shasta, California, by using airborne and satellite remote sensing data

USGS Publications Warehouse

Crowley, J.K.; Hubbard, B.E.; Mars, J.C.

2003-01-01

Remote sensing data from NASA's Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and the first spaceborne imaging spectrometer, Hyperion, show hydrothermally altered rocks mainly composed of natroalunite, kaolinite, cristobalite, and gypsum on both the Mount Shasta and Shastina cones. Field observations indicate that much of the visible altered rock consists of talus material derived from fractured rock zones within and adjacent to dacitic domes and nearby lava flows. Digital elevation data were utilized to distinguish steeply sloping altered bedrock from more gently sloping talus materials. Volume modeling based on the imagery and digital elevation data indicate that Mount Shasta drainage systems contain moderate volumes of altered rock, a result that is consistent with Mount Shasta's Holocene record of mostly small to moderate debris flows. Similar modeling for selected areas at Mount Rainier and Mount Adams, Washington, indicates larger altered rock volumes consistent with the occurrence of much larger Holocene debris flows at those volcanoes. The availability of digital elevation and spectral data from spaceborne sensors, such as Hyperion and the Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER), greatly expands opportunities for studying potential debris flow source characteristics at stratovolcanoes around the world. ?? 2003 Elsevier Inc. All rights reserved.

Numerical model of solar dynamic radiator for parametric analysis

NASA Technical Reports Server (NTRS)

Rhatigan, Jennifer L.

1989-01-01

Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations.

Deposition of amorphous carbon thin films by aerosol-assisted CVD method

NASA Astrophysics Data System (ADS)

Fadzilah, A. N.; Dayana, K.; Rusop, M.

2018-05-01

This paper reports on the deposition of amorphous carbon (a-C) by Aerosol-assisted Chemical Vapor Deposition (AACVD) using natural source of camphor oil as the precursor material. 4 samples were deposited at 4 different deposition flow rate from 15 sccm to 20 sccm, with 5 sccm interval for each sample. The analysis includes the electrical, optical and structural analysis of the data. The a-C structure which came from the manipulation of synthesis parameter was characterized by the solar simulator system, UV-VIS-NIR, Raman spectroscope and AFM. The properties of a-C are highly dependent on the deposition techniques and deposition parameters; hence the influences of gas flow rate were studied.

Systems for column-based separations, methods of forming packed columns, and methods of purifying sample components

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2000-01-01

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2006-02-21

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components.

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2004-08-24

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Advanced thermoplastic resins, phase 1

NASA Technical Reports Server (NTRS)

Hendricks, C. L.; Hill, S. G.; Falcone, A.; Gerken, N. T.

1991-01-01

Eight thermoplastic polyimide resin systems were evaluated as composite matrix materials. Two resins were selected for more extensive mechanical testing and both were versions of LaRC-TPI (Langley Research Center - Thermoplastic Polyimide). One resin was made with LaRC-TPI and contained 2 weight percent of a di(amic acid) dopant as a melt flow aid. The second system was a 1:1 slurry of semicrystalline LaRC-TPI powder in a polyimidesulfone resin diglyme solution. The LaRC-TPI powder melts during processing and increases the melt flow of the resin. Testing included dynamic mechanical analysis, tension and compression testing, and compression-after-impact testing. The test results demonstrated that the LaRC-TPI resins have very good properties compared to other thermoplastics, and that they are promising matrix materials for advanced composite structures.

Chromatographic analysis of Polygalae Radix by online hyphenating pressurized liquid extraction

NASA Astrophysics Data System (ADS)

Song, Yuelin; Song, Qingqing; Li, Jun; Shi, Shepo; Guo, Liping; Zhao, Yunfang; Jiang, Yong; Tu, Pengfei

2016-06-01

Practicing “green analytical chemistry” is of great importance when profiling the chemical composition of complex matrices. Herein, a novel hybrid analytical platform was developed for direct chemical analysis of complex matrices by online hyphenating pressurized warm water extraction followed by turbulent flow chromatography coupled with high performance liquid chromatography-tandem mass spectrometry (PWWE-TFC-LC-MS/MS). Two parallel hollow guard columns acted as extraction vessels connected to a long narrow polyether ether ketone tube, while warm water served as extraction solvent and was delivered at a flow rate of 2.5 mL/min to generate considerable back pressure at either vessel. A column oven heated both the solvent and crude materials. A TFC column, which is advantageous for the comprehensive trapping of small molecular substances from fluids under turbulent flow conditions, was employed to transfer analytes from the PWWE module to LC-MS/MS. Two electronic valves alternated each vessel between extraction and elution phases. As a proof-of-concept, a famous herbal medicine for the treatment of neurodegenerative disorders, namely Polygalae Radix, was selected for the qualitative and quantitative analyses. The results suggest that the hybrid platform is advantageous in terms of decreasing time, material, and solvent consumption and in its automation, versatility, and environmental friendliness.

Fourier Transform Mass Spectrometry and Nuclear Magnetic Resonance Analysis for the Rapid and Accurate Characterization of Hexacosanoylceramide.

PubMed

Ross, Charles W; Simonsick, William J; Bogusky, Michael J; Celikay, Recep W; Guare, James P; Newton, Randall C

2016-06-28

Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI), sheath flow electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and high-field nuclear magnetic resonance (NMR) analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry.

Assessing the debris flow run-out frequency of a catchment in the French Alps using a parameterization analysis with the RAMMS numerical run-out model

NASA Astrophysics Data System (ADS)

Hussin, H. Y.; Luna, B. Quan; van Westen, C. J.; Christen, M.; Malet, J.-P.; van Asch, Th. W. J.

2012-04-01

Debris flows occurring in the European Alps frequently cause significant damage to settlements, power-lines and transportation infrastructure which has led to traffic disruptions, economic loss and even death. Estimating the debris flow run-out extent and the parameter uncertainty related to run-out modeling are some of the difficulties found in the Quantitative Risk Assessment (QRA) of debris flows. Also, the process of the entrainment of material into a debris flow is until now not completely understood. Debris flows observed in the French Alps entrain 5 - 50 times the amount of volume compared to the initially mobilized source volume. In this study we analyze a debris flow that occurred in 2003 at the Faucon catchment in the Barcelonnette Basin (Southern French Alps). The analysis was carried out using the Voellmy rheology and an entrainment model imbedded in the RAMMS 2D numerical modeling software. The historic event was back calibrated based on source, entrainment and deposit volumes, including the run-out distance, velocities and deposit heights of the debris flow. This was then followed by a sensitivity analysis of the rheological and entrainment parameters to produce 120 debris flow scenarios leading to a frequency assessment of the run-out distance and deposit height at the debris fan. The study shows that the Voellmy frictional parameters mainly influence the run-out distance and velocity of the flow, while the entrainment parameter has a major impact on the debris flow height. The frequency assessment of the 120 simulated scenarios further gives an indication on the most likely debris flow run-out extents and heights for this catchment. Such an assessment can be an important link between the rheological model parameters and the spatial probability of the run-out for the Quantitative Risk Assessment (QRA) of debris flows.

Identification of the full anisotropic flow resistivity tensor for multiple glass wool and melamine foam samples.

PubMed

Van der Kelen, Christophe; Göransson, Peter

2013-12-01

The flow resistivity tensor, which is the inverse of the viscous permeability tensor, is one of the most important material properties for the acoustic performance of porous materials used in acoustic treatments. Due to the manufacturing processes involved, these porous materials are most often geometrically anisotropic on a microscopic scale, and for demanding applications, there is a need for improved characterization methods. This paper discusses recent refinements of a method for the identification of the anisotropic flow resistivity tensor. The inverse estimation is verified for three fictitious materials with different degrees of anisotropy. Measurements are performed on nine glass wool samples and seven melamine foam samples, and the anisotropic flow resistivity tensors obtained are validated by comparison to measurements performed on uni-directional cylindrical samples, extracted from the same, previously measured cubic samples. The variability of flow resistivity in the batch of material from which the glass wool is extracted is discussed. The results for the melamine foam suggest that there is a relation between the direction of highest flow resistivity, and the rise direction of the material.

Yielding to Stress: Recent Developments in Viscoplastic Fluid Mechanics

NASA Astrophysics Data System (ADS)

Balmforth, Neil J.; Frigaard, Ian A.; Ovarlez, Guillaume

2014-01-01

The archetypal feature of a viscoplastic fluid is its yield stress: If the material is not sufficiently stressed, it behaves like a solid, but once the yield stress is exceeded, the material flows like a fluid. Such behavior characterizes materials common in industries such as petroleum and chemical processing, cosmetics, and food processing and in geophysical fluid dynamics. The most common idealization of a viscoplastic fluid is the Bingham model, which has been widely used to rationalize experimental data, even though it is a crude oversimplification of true rheological behavior. The popularity of the model is in its apparent simplicity. Despite this, the sudden transition between solid-like behavior and flow introduces significant complications into the dynamics, which, as a result, has resisted much analysis. Over recent decades, theoretical developments, both analytical and computational, have provided a better understanding of the effect of the yield stress. Simultaneously, greater insight into the material behavior of real fluids has been afforded by advances in rheometry. These developments have primed us for a better understanding of the various applications in the natural and engineering sciences.

A novel effective micromixer having horizontal and vertical weaving flow motion

NASA Astrophysics Data System (ADS)

Yoo, Won-Sul; Go, Jung Sang; Park, Seonghun; Park, Sang-Hu

2012-03-01

The need for small-scale product-related biotechnology (BT) is rapidly increasing. An important product among these is high-performance biochips. In these devices, many microchannels are used for separation, filtering and mixing of various materials; therefore, for compactness, these reactions should be carried out in the small space of microfluidic systems. However, there is no turbulence that can induce materials to be mixed or reacted in the microchannel, especially with low Reynolds number laminar flow. Hence, it is difficult to sufficiently mix different materials. To address this problem, we propose the HVW (horizontal and vertical weaving) micromixer having crossed barriers inside of a microchannel, for effective mixing and reacting different materials. From CFD analysis, we have evaluated the mixing mechanism and efficiency of the HVW mixer. In this work, it is shown that the HVW mixer has the maximum mixing efficiency of 89.9% with a short mixing distance of 450 µm at a Reynolds number of 5 with the barrier angle of 30°, when water and water combined with Rhodamine B figment were used as fluids.

Friction law and hysteresis in granular materials

PubMed Central

Wyart, M.

2017-01-01

The macroscopic friction of particulate materials often weakens as the flow rate is increased, leading to potentially disastrous intermittent phenomena including earthquakes and landslides. We theoretically and numerically study this phenomenon in simple granular materials. We show that velocity weakening, corresponding to a nonmonotonic behavior in the friction law, μ(I), is present even if the dynamic and static microscopic friction coefficients are identical, but disappears for softer particles. We argue that this instability is induced by endogenous acoustic noise, which tends to make contacts slide, leading to faster flow and increased noise. We show that soft spots, or excitable regions in the materials, correspond to rolling contacts that are about to slide, whose density is described by a nontrivial exponent θs. We build a microscopic theory for the nonmonotonicity of μ(I), which also predicts the scaling behavior of acoustic noise, the fraction of sliding contacts χ, and the sliding velocity, in terms of θs. Surprisingly, these quantities have no limit when particles become infinitely hard, as confirmed numerically. Our analysis rationalizes previously unexplained observations and makes experimentally testable predictions. PMID:28811373

Friction law and hysteresis in granular materials

NASA Astrophysics Data System (ADS)

DeGiuli, E.; Wyart, M.

2017-08-01

The macroscopic friction of particulate materials often weakens as the flow rate is increased, leading to potentially disastrous intermittent phenomena including earthquakes and landslides. We theoretically and numerically study this phenomenon in simple granular materials. We show that velocity weakening, corresponding to a nonmonotonic behavior in the friction law, μ(I), is present even if the dynamic and static microscopic friction coefficients are identical, but disappears for softer particles. We argue that this instability is induced by endogenous acoustic noise, which tends to make contacts slide, leading to faster flow and increased noise. We show that soft spots, or excitable regions in the materials, correspond to rolling contacts that are about to slide, whose density is described by a nontrivial exponent θs. We build a microscopic theory for the nonmonotonicity of μ(I), which also predicts the scaling behavior of acoustic noise, the fraction of sliding contacts χ, and the sliding velocity, in terms of θs. Surprisingly, these quantities have no limit when particles become infinitely hard, as confirmed numerically. Our analysis rationalizes previously unexplained observations and makes experimentally testable predictions.

E-waste management and resources recovery in France.

PubMed

Vadoudi, Kiyan; Kim, Junbeum; Laratte, Bertrand; Lee, Seung-Jin; Troussier, Nadège

2015-10-01

There are various issues of concern regarding electronic waste management, such as the toxicity of hazardous materials and the collection, recycling and recovery of useful resources. To understand the fate of electronic waste after collection and recycling, a products and materials flow analysis should be performed. This is a critical need, as material resources are becoming increasingly scarce and recycling may be able to provide secondary sources for new materials in the future. In this study, we investigate electronic waste systems, specifically the resource recovery or recycling aspects, as well as mapping electronic waste flows based on collection data in France. Approximately 1,588,453 t of new electrical and electronic equipment were sold in the French market in 2010. Of this amount, 430,000 t of electronic waste were collected, with the remaining 1,128,444 t remaining in stock. Furthermore, the total recycled amounts were 354,106 t and 11,396 t, respectively. The main electronic waste materials were ferrous metals (37%), plastic (22%), aluminium (12%), copper (11%) and glass (7%). This study will contribute to developing sustainable electronic waste and resource recycling systems in France. © The Author(s) 2015.

Rheological of chocolate-flavored, reduced-calories coating as a function of conching process.

PubMed

Medina-Torres, Luis; Sanchez-Olivares, Guadalupe; Nuñez-Ramirez, Diola Marina; Moreno, Leonardo; Calderas, Fausto

2014-07-01

Continuous flow and linear viscoelasticity rheology of chocolate coating is studied in this work using fat substitute gums (xanthan, GX). An alternative conching process, using a Rotor-Estator (RE) type impeller, is proposed. The objective is to obtain a chocolate coating material with improved flow properties. Characterization of the final material through particle size distribution (PSD), differential scanning calorimetry (DSC) and proximal analysis is reported. Particle size distribution of the final material showed less polydispersity and therefore, greater homogeneity; fusion points were also generated at around 20 °C assuming crystal type I (β'2) and II (α). Moreover, the final material exhibited crossover points (higher structure material), whereas the commercial brand chocolate used for comparison did not. The best conditions to produce the coating were maturing of 36 h and 35 °C, showing crossover points around 76 Pa and a 0.505 solids particle dispersion (average particle diameter of 0.364 μm), and a fusion point at 20.04 °C with a ΔHf of 1.40 (J/g). The results indicate that xanthan gum is a good substitute for cocoa butter and provides stability to the final product.

Risk management and measuring productivity with POAS--Point of Act System--a medical information system as ERP (Enterprise Resource Planning) for hospital management.

PubMed

Akiyama, M

2007-01-01

The concept of our system is not only to manage material flows, but also to provide an integrated management resource, a means of correcting errors in medical treatment, and applications to EBM (evidence-based medicine) through the data mining of medical records. Prior to the development of this system, electronic processing systems in hospitals did a poor job of accurately grasping medical practice and medical material flows. With POAS (Point of Act System), hospital managers can solve the so-called, "man, money, material, and information" issues inherent in the costs of healthcare. The POAS system synchronizes with each department system, from finance and accounting, to pharmacy, to imaging, and allows information exchange. We can manage Man (Business Process), Material (Medical Materials and Medicine), Money (Expenditure for purchase and Receipt), and Information (Medical Records) completely by this system. Our analysis has shown that this system has a remarkable investment effect - saving over four million dollars per year - through cost savings in logistics and business process efficiencies. In addition, the quality of care has been improved dramatically while error rates have been reduced - nearly to zero in some cases.

A Generalized Eulerian-Lagrangian Analysis, with Application to Liquid Flows with Vapor Bubbles

NASA Technical Reports Server (NTRS)

Dejong, Frederik J.; Meyyappan, Meyya

1993-01-01

Under a NASA MSFC SBIR Phase 2 effort an analysis has been developed for liquid flows with vapor bubbles such as those in liquid rocket engine components. The analysis is based on a combined Eulerian-Lagrangian technique, in which Eulerian conservation equations are solved for the liquid phase, while Lagrangian equations of motion are integrated in computational coordinates for the vapor phase. The novel aspect of the Lagrangian analysis developed under this effort is that it combines features of the so-called particle distribution approach with those of the so-called particle trajectory approach and can, in fact, be considered as a generalization of both of those traditional methods. The result of this generalization is a reduction in CPU time and memory requirements. Particle time step (stability) limitations have been eliminated by semi-implicit integration of the particle equations of motion (and, for certain applications, the particle temperature equation), although practical limitations remain in effect for reasons of accuracy. The analysis has been applied to the simulation of cavitating flow through a single-bladed section of a labyrinth seal. Models for the simulation of bubble formation and growth have been included, as well as models for bubble drag and heat transfer. The results indicate that bubble formation is more or less 'explosive'. for a given flow field, the number density of bubble nucleation sites is very sensitive to the vapor properties and the surface tension. The bubble motion, on the other hand, is much less sensitive to the properties, but is affected strongly by the local pressure gradients in the flow field. In situations where either the material properties or the flow field are not known with sufficient accuracy, parametric studies can be carried out rapidly to assess the effect of the important variables. Future work will include application of the analysis to cavitation in inducer flow fields.

Drying of pulverized material with heated condensible vapor

DOEpatents

Carlson, Larry W.

1986-01-01

Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fins, on the outer lateral surface thereof. The cooled collection fins are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized material then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal.

DEM study of granular flow around blocks attached to inclined walls

NASA Astrophysics Data System (ADS)

Samsu, Joel; Zhou, Zongyan; Pinson, David; Chew, Sheng

2017-06-01

Damage due to intense particle-wall contact in industrial applications can cause severe problems in industries such as mineral processing, mining and metallurgy. Studying the flow dynamics and forces on containing walls can provide valuable feedback for equipment design and optimising operations to prolong the equipment lifetime. Therefore, solids flow-wall interaction phenomena, i.e. induced wall stress and particle flow patterns should be well understood. In this work, discrete element method (DEM) is used to study steady state granular flow in a gravity-fed hopper like geometry with blocks attached to an inclined wall. The effects of different geometries, e.g. different wall angles and spacing between blocks are studied by means of a 3D DEM slot model with periodic boundary conditions. The findings of this work include (i) flow analysis in terms of flow patterns and particle velocities, (ii) force distributions within the model geometry, and (iii) wall stress vs. model height diagrams. The model enables easy transfer of the key findings to other industrial applications handling granular materials.

Highly controllable ICP etching of GaAs based materials for grating fabrication

NASA Astrophysics Data System (ADS)

Weibin, Qiu; Jiaxian, Wang

2012-02-01

Highly controllable ICP etching of GaAs based materials with SiCl4/Ar plasma is investigated. A slow etching rate of 13 nm/min was achieved with RF1 D 10 W, RF2 D 20 W and a high ratio of Ar to SiCl4 flow. First order gratings with 25 nm depth and 140 nm period were fabricated with the optimal parameters. AFM analysis indicated that the RMS roughness over a 10 × 10 μm2 area was 0.3 nm, which is smooth enough to regrow high quality materials for devices.

Assessment of critical path analyses of the relationship between permeability and electrical conductivity of pore networks

USDA-ARS?s Scientific Manuscript database

Critical path analysis (CPA) is a method for estimating macroscopic transport coefficients of heterogeneous materials that are highly disordered at the micro-scale. Developed originally to model conduction in semiconductors, numerous researchers have noted that CPA might also have relevance to flow ...

Evaluation of design methods to determine scour depths for bridge structures : LTRC research project capsule 08-3ST.

DOT National Transportation Integrated Search

2009-04-01

Scour, an engineering term for erosion, is : the result of the erosive action of flowing : water excavating and carrying away : material from the bed and banks of : streams and from around the piers and : abutments of bridges. For analysis : purposes...

Convection-Enhanced Transport into Open Cavities : Effect of Cavity Aspect Ratio.

PubMed

Horner, Marc; Metcalfe, Guy; Ottino, J M

2015-09-01

Recirculating fluid regions occur in the human body both naturally and pathologically. Diffusion is commonly considered the predominant mechanism for mass transport into a recirculating flow region. While this may be true for steady flows, one must also consider the possibility of convective fluid exchange when the outer (free stream) flow is transient. In the case of an open cavity, convective exchange occurs via the formation of lobes at the downstream attachment point of the separating streamline. Previous studies revealed the effect of forcing amplitude and frequency on material transport rates into a square cavity (Horner in J Fluid Mech 452:199-229, 2002). This paper summarizes the effect of cavity aspect ratio on exchange rates. The transport process is characterized using both computational fluid dynamics modeling and dye-advection experiments. Lagrangian analysis of the computed flow field reveals the existence of turnstile lobe transport for this class of flows. Experiments show that material exchange rates do not vary linearly as a function of the cavity aspect ratio (A = W/H). Rather, optima are predicted for A ≈ 2 and A ≈ 2.73, with a minimum occurring at A ≈ 2.5. The minimum occurs at the point where the cavity flow structure bifurcates from a single recirculating flow cell into two corner eddies. These results have significant implications for mass transport environments where the geometry of the flow domain evolves with time, such as coronary stents and growing aneurysms. Indeed, device designers may be able to take advantage of the turnstile-lobe transport mechanism to tailor deposition rates near newly implanted medical devices.

Numerical analysis of the non-contacting gas face seals

NASA Astrophysics Data System (ADS)

Blasiak, S.

2017-08-01

The non-contacting gas face seals are used in high-performance devices where the main requirements are safety and reliability. Compliance with these requirements is made possible by careful research and analysis of physical processes related to, inter alia, fluid flow through the radial gap and ring oscillations susceptible to being housed in the enclosure under the influence of rotor kinematic forces. Elaborating and developing mathematical models describing these phenomena allows for more and more accurate analysis results. The paper presents results of studies on stationary ring oscillations made of different types of materials. The presented results of the research allow to determine which of the materials used causes the greatest amplitude of the vibration of the system fluid film-working rings.

Evaluation of Flow-Injection Tandem Mass Spectrometry for Rapid and High-Throughput Quantitative Determination of B-Vitamins in Nutritional Supplements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhandari, Deepak; Van Berkel, Gary J

2012-01-01

The use of flow-injection electrospray ionization tandem mass spectrometry for rapid and high-throughput mass spectral analysis of selected B-vitamins, viz. B1, B2, B3, B5, and B6, in nutritional formulations was demonstrated. A simple and rapid (~5 min) in-tube sample preparation was performed by adding extraction solvent to a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Automated flow injection introduced 1 L of the extracts directly into the mass spectrometer ion source without chromatographic separation. Sample-to-sample analysis time was 60 s representing significant improvement over conventional liquid chromatography approaches which typically require 25-45more » min, and often require more significant sample preparation procedures. Quantitative capabilities of the flow-injection analysis were tested using the method of standard additions and NIST standard reference material (SRM 3280) multivitamin/multielement tablets. The quantity determined for each B-vitamin in SRM 3280 was within the statistical range provided for the respective certified values. The same sample preparation and analysis approach was also applied to two different commercial vitamin supplement tablets and proved to be successful in the quantification of the selected B-vitamins as evidenced by an agreement with the labels values and the results obtained using isotope dilution liquid chromatography/mass spectrometry.« less

Improvement and analysis of the hydrogen-cerium redox flow cell

DOE PAGES

Tucker, Michael C.; Weiss, Alexandra; Weber, Adam Z.

2016-08-03

In this paper, the H 2-Ce redox flow cell is optimized using commercially-available cell materials. Cell performance is found to be sensitive to the upper charge cutoff voltage, membrane boiling pretreatment, methanesulfonic-acid concentration, (+) electrode surface area and flow pattern, and operating temperature. Performance is relatively insensitive to membrane thickness, Cerium concentration, and all features of the (-) electrode including hydrogen flow. Cell performance appears to be limited by mass transport and kinetics in the cerium (+) electrode. Maximum discharge power of 895 mW cm -2 was observed at 60 °C; an energy efficiency of 90% was achieved at 50more » °C. Finally, the H 2-Ce cell is promising for energy storage assuming one can optimize Ce reaction kinetics and electrolyte.« less

Doing more with less (data): complexities of resource flow analysis in the Gauteng City-Region

NASA Astrophysics Data System (ADS)

Culwick, Christina; Götz, Graeme; Butcher, Siân; Harber, Jesse; Maree, Gillian; Mushongera, Darlington

2017-12-01

Urban metabolism is a growing field of study into resource flows through cities, and how these could be managed more sustainably. There are two main schools of thought on urban metabolism—metabolic flow analysis (MFA) and urban political ecology (UPE). The two schools remain siloed despite common foundations. This paper reflects on recent research by the Gauteng City-Region Observatory (GCRO) into urban sustainability transitions in South Africa’s Gauteng City-Region, a large and sprawling urban formation that faces a host of sustainability challenges including water deficits, erratic electricity supply, stretched infrastructure networks and increasingly carbon-intensive settlement patterns. Three GCRO research projects are reviewed. Each project began with the assumption that data collection on the region’s metabolism could enable an MFA or MFA-like analysis to highlight where possible resource efficiency and sustainability gains might be achieved. However, in each case we confronted severe data-limitations, and ended up asking UPE-style questions on the reasons for and implications of the chronic paucity of urban metabolism data. We have been led to conclude that urban metabolism research will require much more than just assembling and modelling flows data, although these efforts should not be abandoned. A synthesis of MFA and UPE is needed, which simultaneously builds a deeper understanding of resource flows and the systems that govern these flows. We support the emerging approach in political-industrial ecology literature which values both material data on and socio-political insight into urban metabolism, and emphasises the importance of multi-disciplinary and multi-dimensional analysis to inform decision-making in urban sustainability transitions.

Design approach of an aquaculture cage system for deployment in the constructed channel flow environments of a power plant

PubMed Central

Lee, Jihoon; Fredriksson, David W.; DeCew, Judson; Drach, Andrew; Yim, Solomon C.

2018-01-01

This study provides an engineering approach for designing an aquaculture cage system for use in constructed channel flow environments. As sustainable aquaculture has grown globally, many novel techniques have been introduced such as those implemented in the global Atlantic salmon industry. The advent of several highly sophisticated analysis software systems enables the development of such novel engineering techniques. These software systems commonly include three-dimensional (3D) drafting, computational fluid dynamics, and finite element analysis. In this study, a combination of these analysis tools is applied to evaluate a conceptual aquaculture system for potential deployment in a power plant effluent channel. The channel is supposedly clean; however, it includes elevated water temperatures and strong currents. The first portion of the analysis includes the design of a fish cage system with specific net solidities using 3D drafting techniques. Computational fluid dynamics is then applied to evaluate the flow reduction through the system from the previously generated solid models. Implementing the same solid models, a finite element analysis is performed on the critical components to assess the material stresses produced by the drag force loads that are calculated from the fluid velocities. PMID:29897954

Active hopper for promoting flow of bulk granular or powdered solids

DOEpatents

Saunders, Timothy; Brady, John D.

2013-04-02

An apparatus that promotes the flow of materials has a body having an inner shape for holding the materials, a wall having a shape that approximates a portion of the inner shape of the body, and a vibrator attached to the wall. The wall may be disposed vertically within the body close to the body's inner shape. The vibrator transfers vibrations to the wall to agitate the material and encourage material flow.

A High-Resolution Godunov Method for Compressible Multi-Material Flow on Overlapping Grids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banks, J W; Schwendeman, D W; Kapila, A K

2006-02-13

A numerical method is described for inviscid, compressible, multi-material flow in two space dimensions. The flow is governed by the multi-material Euler equations with a general mixture equation of state. Composite overlapping grids are used to handle complex flow geometry and block-structured adaptive mesh refinement (AMR) is used to locally increase grid resolution near shocks and material interfaces. The discretization of the governing equations is based on a high-resolution Godunov method, but includes an energy correction designed to suppress numerical errors that develop near a material interface for standard, conservative shock-capturing schemes. The energy correction is constructed based on amore » uniform pressure-velocity flow and is significant only near the captured interface. A variety of two-material flows are presented to verify the accuracy of the numerical approach and to illustrate its use. These flows assume an equation of state for the mixture based on Jones-Wilkins-Lee (JWL) forms for the components. This equation of state includes a mixture of ideal gases as a special case. Flow problems considered include unsteady one-dimensional shock-interface collision, steady interaction of an planar interface and an oblique shock, planar shock interaction with a collection of gas-filled cylindrical inhomogeneities, and the impulsive motion of the two-component mixture in a rigid cylindrical vessel.« less

[The progress in speciation analysis of trace elements by atomic spectrometry].

PubMed

Wang, Zeng-Huan; Wang, Xu-Nuo; Ke, Chang-Liang; Lin, Qin

2013-12-01

The main purpose of the present work is to review the different non-chromatographic methods for the speciation analysis of trace elements in geological, environmental, biological and medical areas. In this paper, the sample processing methods in speciation analysis were summarized, and the main strategies for non-chromatographic technique were evaluated. The basic principles of the liquid extractions proposed in the published literatures recently and their advantages and disadvantages were discussed, such as conventional solvent extraction, cloud point extraction, single droplet microextraction, and dispersive liquid-liquid microextraction. Solid phase extraction, as a non-chromatographic technique for speciation analysis, can be used in batch or in flow detection, and especially suitable for the online connection to atomic spectrometric detector. The developments and applications of sorbent materials filled in the columns of solid phase extraction were reviewed. The sorbents include chelating resins, nanometer materials, molecular and ion imprinted materials, and bio-sorbents. Other techniques, e. g. hydride generation technique and coprecipitation, were also reviewed together with their main applications.

Periodic flow hydrodynamic resistance parameters for woven screen matrices at cryogenic temperatures

NASA Astrophysics Data System (ADS)

Perrella, M. D.; Ghiaasiaan, S. M.

2017-12-01

The regenerator is a critical component in all Stirling and Pulse Tube cryocoolers. It generally consists of a microporous metallic or rare-earth filler material contained within a cylindrical shell. Accurate modelling of the hydrodynamic and thermal behaviour of different regenerator materials is crucial to the successful design of cryogenic systems. Previous investigations have used experimental measurements at steady and periodic flow conditions in conjunction with pore-level CFD analysis to determine the pertinent hydrodynamic parameters, namely the Darcy permeability and Forchheimer coefficients. Due to the difficulty associated with experimental measurement at cryogenic temperatures, past investigations were mostly performed at ambient conditions and their results are assumed to be appropriate for cryogenic temperatures. In this study, a regenerator filled with woven screen matrices such as 400 mesh T316 stainless steel were assembled and experimentally tested under periodic helium flow at cryogenic temperatures. The mass flow and pressure drop data were analysed using CFD to determine the dimensionless friction factor, Darcy Permeability and Forchheimer coefficients. These results are compared to previous investigations at ambient temperature conditions, and the relevance of room-temperature models and correlations to cryogenic temperatures is critically assessed.

Tensile properties and flow behavior analysis of modified 9Cr-1Mo steel clad tube material

NASA Astrophysics Data System (ADS)

Singh, Kanwarjeet; Latha, S.; Nandagopal, M.; Mathew, M. D.; Laha, K.; Jayakumar, T.

2014-11-01

The tensile properties and flow behavior of modified 9Cr-1Mo steel clad tube have been investigated in the framework of various constitutive equations for a wide range of temperatures (300-923 K) and strain rates (3 × 10-3 s-1, 3 × 10-4 s-1 and 3 × 10-5 s-1). The tensile flow behavior of modified 9Cr-1Mo steel clad tube was most accurately described by Voce equation. The variation of instantaneous work hardening rate (θ = dσ/dε) and σθ with stress (σ) indicated two stage behavior characterized by rapid decrease at low stresses (transient stage) followed by a gradual decrease in high stresses (Stage III). The variation of work hardening parameters and work hardening rate in terms of θ vs. σ and σθ vs. σ with temperature exhibited three distinct regimes. Rapid decrease in flow stress and work hardening parameters and rapid shift of θ vs. σ and σθ vs. σ towards low stresses with increase in temperature indicated dynamic recovery at high temperatures. Tensile properties of the material have been best predicted from Voce equation.

The Use of Logistics n the Quality Parameters Control System of Material Flow

ERIC Educational Resources Information Center

Karpova, Natalia P.; Toymentseva, Irina A.; Shvetsova, Elena V.; Chichkina, Vera D.; Chubarkova, Elena V.

2016-01-01

The relevance of the research problem is conditioned on the need to justify the use of the logistics methodologies in the quality parameters control process of material flows. The goal of the article is to develop theoretical principles and practical recommendations for logistical system control in material flows quality parameters. A leading…

Effects of Surface and Subsurface Bed Material Composition on Gravel Transport and Flow Competence Relations—Possibilities for Prediction

NASA Astrophysics Data System (ADS)

Bunte, K.; Abt, S. R.; Swingle, K. W.; Cenderelli, D. A.; Gaeuman, D. A.

2014-12-01

Bedload transport and flow competence relations are difficult to predict in coarse-bedded steep streams where widely differing sediment supply, bed stability, and complex flow hydraulics greatly affect amounts and sizes of transported gravel particles. This study explains how properties of bed material surface and subsurface size distributions are directly related to gravel transport and may be used for prediction of gravel transport and flow competence relations. Gravel transport, flow competence, and bed material size were measured in step-pool and plane-bed streams. Power functions were fitted to gravel transport QB=aQb and flow competence Dmax=cQd relations; Q is water discharge. Frequency distributions of surface FDsurf and subsurface FDsub bed material were likewise described by power functions FDsurf=hD j and FDsub=kDm fitted over six 0.5-phi size classes within 4 to 22.4 mm. Those gravel sizes are typically mobile even in moderate floods. Study results show that steeper subsurface bed material size distributions lead to steeper gravel transport and flow competence relations, whereas larger amounts of sediment contained in those 6 size bedmaterial classes (larger h and k) flatten the relations. Similarly, steeper surface size distributions decrease the coefficients of the gravel transport and flow competence relations, whereas larger amounts of sediment within the six bed material classes increase the intercepts of gravel transport and flow competence relations. Those relations are likely causative in streams where bedload stems almost entirely from the channel bed as opposed to direct (unworked) contributions from hillslopes and tributaries. The exponent of the subsurface bed material distribution m predicted the gravel transport exponent b with r2 near 0.7 and flow competence exponent d with r2 near 0.5. The intercept of bed surface distributions h increased the intercept a of gravel transport and c of the flow competence relations with r2 near 0.6.

Analysis of Stresses in German Airplanes

NASA Technical Reports Server (NTRS)

Hoff, Wilhelm

1923-01-01

This report contains an account of the origin of the views and fundamental principles underlying the construction of German airplanes during the war. The report contains a detailed discussion of the aerodynamic principles and their use in determining the strength of airplanes, the analysis of the strength qualities of materials and in the construction, the calculated strength of air flows and a description of tests made in determining the strength of airplanes.

Reprint Of: Enhanced spatially-resolved trace analysis using combined SIMS-single-stage AMS

NASA Astrophysics Data System (ADS)

Grabowski, K. S.; Groopman, E. E.; Fahey, A. J.

2018-01-01

Secondary ion mass spectrometry (SIMS) provides spatially resolved trace analysis of solid materials, but can be complicated by unresolved abundant molecular isobars. By adding a 300-kV single-stage accelerator mass spectrometer (SSAMS) as a detector for a Cameca ims 4f SIMS, one can measure more abundant positive ions from the SIMS while removing molecular isobars, thus improving very low abundance trace element and isotope analysis. This paper describes important features and capabilities of such an integrated system at the Naval Research Laboratory using charge state +1 ions. Transmission loss is compared to molecule destruction as gas flow to the molecule-destruction cell increases. As most measurements tolerate more modest abundance sensitivities than for 14C analysis, a lower gas flow is acceptable, so good transmission of 20-50% for ions of interest can be maintained for a broad range of ion masses. This new instrument has measured isotope ratios for uranium, lead, rare earths, and other elements from particulates and localized regions, with molecule destruction enabling the measurement at low SIMS mass resolving power and thus high transmission, as examples will show. This new and world-unique instrument provides improved capabilities for applications in nuclear and other forensics, geochemistry, cosmochemistry, and the development of optical, electronic, multifunctional, and structural materials.

Enhanced spatially-resolved trace analysis using combined SIMS-single-stage AMS

NASA Astrophysics Data System (ADS)

Grabowski, K. S.; Groopman, E. E.; Fahey, A. J.

2017-11-01

Secondary ion mass spectrometry (SIMS) provides spatially resolved trace analysis of solid materials, but can be complicated by unresolved abundant molecular isobars. By adding a 300-kV single-stage accelerator mass spectrometer (SSAMS) as a detector for a Cameca ims 4f SIMS, one can measure more abundant positive ions from the SIMS while removing molecular isobars, thus improving very low abundance trace element and isotope analysis. This paper describes important features and capabilities of such an integrated system at the Naval Research Laboratory using charge state +1 ions. Transmission loss is compared to molecule destruction as gas flow to the molecule-destruction cell increases. As most measurements tolerate more modest abundance sensitivities than for 14C analysis, a lower gas flow is acceptable, so good transmission of 20-50% for ions of interest can be maintained for a broad range of ion masses. This new instrument has measured isotope ratios for uranium, lead, rare earths, and other elements from particulates and localized regions, with molecule destruction enabling the measurement at low SIMS mass resolving power and thus high transmission, as examples will show. This new and world-unique instrument provides improved capabilities for applications in nuclear and other forensics, geochemistry, cosmochemistry, and the development of optical, electronic, multifunctional, and structural materials.

Research on the Stress and Material Flow with Single Particle—Simulations and Experiments

NASA Astrophysics Data System (ADS)

Zhang, Tao; Jiang, Feng; Yan, Lan; Xu, Xipeng

2017-04-01

The scratching process of particle is a complex material removal process involving cutting, plowing, and rubbing. In this study, scratch experiments under different loads are performed on a multifunctional tester for material surface. Natural diamond and Fe-Cr-Ni stainless steel are chosen as indenter and workpiece material, respectively. The cutting depth and side flow height of scratch are measured using a white light interferometer. The finite element model is developed, and the numerical simulation of scratching is conducted using AdvantEdgeTM. The simulated forces and side flow height under different cutting depths correspond well with experimental results, validating the accuracy of the scratching simulation. The mises stress distribution of the particle is presented, with the maximum stress occurring inside the particle rather than on the surface. The pressure distribution of the particle is also given, and results show that the maximum pressure occurs on the contact surface of particle and workpiece. The material flow contour is presented, and material flow direction and velocity magnitude are analyzed.

Designing shear-thinning

NASA Astrophysics Data System (ADS)

Nelson, Arif Z.; Ewoldt, Randy H.

2017-11-01

Design in fluid mechanics often focuses on optimizing geometry (airfoils, surface textures, microfluid channels), but here we focus on designing fluids themselves. The dramatically shear-thinning ``yield-stress fluid'' is currently the most utilized non-Newtonian fluid phenomenon. These rheologically complex materials, which undergo a reversible transition from solid-like to liquid-like fluid flow, are utilized in pedestrian products such as paint and toothpaste, but also in emerging applications like direct-write 3D printing. We present a paradigm for yield-stress fluid design that considers constitutive model representation, material property databases, available predictive scaling laws, and the many ways to achieve a yield stress fluid, flipping the typical structure-to-rheology analysis to become the inverse: rheology-to-structure with multiple possible materials as solutions. We describe case studies of 3D printing inks and other flow scenarios where designed shear-thinning enables performance remarkably beyond that of Newtonian fluids. This work was supported by Wm. Wrigley Jr. Company and the National Science Foundation under Grant No. CMMI-1463203.

Analysis and Prediction of the Billet Butt and Transverse Weld in the Continuous Extrusion Process of a Hollow Aluminum Profile

NASA Astrophysics Data System (ADS)

Lou, Shumei; Wang, Yongxiao; Liu, Chuanxi; Lu, Shuai; Liu, Sujun; Su, Chunjian

2017-08-01

In continuous extrusions of aluminum profiles, the thickness of the billet butt and the length of the discarded extrudate containing the transverse weld play key roles in reducing material loss and improving product quality. The formation and final distribution of the billet butt and transverse weld depend entirely on the flow behavior of the billet skin material. This study examined the flow behavior of the billet skin material as well as the formation and evolution of the billet butt and the transverse weld in detail through numerical simulation and a series of experiments. In practical extrusions, even if the billet skin is removed by lathe turning shortly before extrusion, billet skin impurities are still distributed around the transverse weld and in the billet butt. The thickness of the scrap billet butt and the length of the discarded extrudate containing the transverse weld can be exactly predicted via simulation.

Electrochemical hydride generation for the simultaneous determination of hydride forming elements by inductively coupled plasma-atomic emission spectrometry

NASA Astrophysics Data System (ADS)

Bolea, E.; Laborda, F.; Castillo, J. R.; Sturgeon, R. E.

2004-04-01

Simultaneous measurements of As, Sb, Se, Sn and Ge were performed by inductively coupled plasma atomic emission spectrometry following their electrochemical hydride generation. An electrochemical hydride generator based on a concentric arrangement with a porous cathode, working in a continuous flow mode was used. The effects of sample flow rate, applied current and electrolytic solution concentration on response were studied and their influence on the mechanisms of hydride generation discussed. Four materials, particulate lead, reticulated vitreous carbon (RVC), silver and amalgamated silver were tested as cathode materials. The best results were achieved with particulate lead and RVC cathodes, wherein generation efficiencies higher than 80% were estimated for most of the analytes. In general, limits of detection between 0.1 and 3.6 ng ml -1 and a precision better than 5% were achieved using a lead cathode. The analysis of a marine sediment reference material (PACS-2, NRC) showed good agreement with the certified values for As and Se.

System and method for measuring permeability of materials

DOEpatents

Hallman, Jr., Russell Louis; Renner, Michael John

2013-07-09

Systems and methods are provided for measuring the permeance of a material. The permeability of the material may also be derived. Systems typically provide a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

Material permeance measurement system and method

DOEpatents

Hallman, Jr., Russell Louis; Renner, Michael John [Oak Ridge, TN

2012-05-08

A system for measuring the permeance of a material. The permeability of the material may also be derived. The system provides a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

Characterization, Operation and Analysis of Test Motors Containing Aluminized Hybrid Fuels

NASA Technical Reports Server (NTRS)

Kibbey, Timothy P.; Cortopassi, Andrew C.; Boyer, J. Eric

2017-01-01

NASA Marshall Space Flight Center's Materials and Processes Department, with support from the Propulsion Systems Department, has renewed the development and maintenance of a hybrid test bed for exposing ablative thermal protection materials to an environment similar to that seen in solid rocket motors (SRM). The Solid Fuel Torch (SFT), operated during the Space Shuttle program, utilized gaseous oxygen for oxidizer and an aluminized hydroxyl-terminated polybutadiene (HTPB) fuel grain to expose a converging section of phenolic material to a 400 psi, 2-phase flow combustion environment. The configuration allows for up to a 2 foot long, 5 inch diameter fuel grain cartridge. Wanting to now test rubber insulation materials with a turn-back feature to mimic the geometry of an aft dome being impinged by alumina particles, the throat area has now been increased by several times to afford flow similarity. Combined with the desire to maintain a higher operating pressure, the oxidizer flow rate is being increased by a factor of 10. Out of these changes has arisen the need to characterize the fuel/oxidizer combination in a higher mass flux condition than has been previously tested at MSFC, and at which the literature has little to no reporting as well. Testing for fuel regression rate comprised a two-level, full factorial design available over Aluminum loading level, mass flow rate, pressure, and diameter. The data taken significantly surpasses the previous available data on regression rate of aluminized HTPB fuel burning with gaseous oxygen. It encompasses higher mass fluxes, and appears to generate more consistent data. The good test article and facility design and testing work of the Penn State HPCL combined with careful analysis of the data and good planning has made this possible. This should be able to assist with developing rate laws that are useful both for research planning and for developing flight system sizing relationships that can help optimize hybrid rocket concepts for trade studies. The successful approach of this DOE and test setup is applicable to other propellant combinations as well.

Flow diagram analysis of electrical fatalities in construction industry.

PubMed

Chi, Chia-Fen; Lin, Yuan-Yuan; Ikhwan, Mohamad

2012-01-01

The current study reanalyzed 250 electrical fatalities in the construction industry from 1996 to 2002 into seven patterns based on source of electricity (power line, energized equipment, improperly installed or damaged equipment), direct contact or indirect contact through some source of injury (boom vehicle, metal bar or pipe, and other conductive material). Each fatality was coded in terms of age, company size, experience, performing tasks, source of injury, accident cause and hazard pattern. The Chi-square Automatic Interaction Detector (CHAID) was applied to the coded data of the fatal electrocution to find a subset of predictors that might derive meaningful classifications or accidents scenarios. A series of Flow Diagrams was constructed based on CHAID result to illustrate the flow of electricity travelling from electrical source to human body. Each of the flow diagrams can be directly linked with feasible prevention strategies by cutting the flow of electricity.

Yield stress materials in soft condensed matter

NASA Astrophysics Data System (ADS)

Bonn, Daniel; Denn, Morton M.; Berthier, Ludovic; Divoux, Thibaut; Manneville, Sébastien

2017-07-01

A comprehensive review is presented of the physical behavior of yield stress materials in soft condensed matter, which encompasses a broad range of materials from colloidal assemblies and gels to emulsions and non-Brownian suspensions. All these disordered materials display a nonlinear flow behavior in response to external mechanical forces due to the existence of a finite force threshold for flow to occur: the yield stress. Both the physical origin and rheological consequences associated with this nonlinear behavior are discussed and an overview is given of experimental techniques available to measure the yield stress. Recent progress is discussed concerning a microscopic theoretical description of the flow dynamics of yield stress materials, emphasizing, in particular, the role played by relaxation time scales, the interplay between shear flow and aging behavior, the existence of inhomogeneous shear flows and shear bands, wall slip, and nonlocal effects in confined geometries.

Jet-controlled freeze valve for use in a glass melter

DOEpatents

Routt, K.R.

1985-07-29

A drain valve for use in furnace for the melting of thermoplastic material is disclosed. The furnace includes a drain cavity formed in its bottom for withdrawing a flow of thermoplastic material. The drain valve includes a flow member which include a flow tube having an inlet and outlet for the material, and coaxially disposed concentric tubular members defining annuli surrounding the flow tube. The tubular members include heating and cooling means for the flow tube. The drain valve can also be used in a furnace of glass melting that includes a drain cavity for withdrawing molten glass from the furnace.

Parameterization of a numerical 2-D debris flow model with entrainment: a case study of the Faucon catchment, Southern French Alps

NASA Astrophysics Data System (ADS)

Hussin, H. Y.; Luna, B. Quan; van Westen, C. J.; Christen, M.; Malet, J.-P.; van Asch, Th. W. J.

2012-10-01

The occurrence of debris flows has been recorded for more than a century in the European Alps, accounting for the risk to settlements and other human infrastructure that have led to death, building damage and traffic disruptions. One of the difficulties in the quantitative hazard assessment of debris flows is estimating the run-out behavior, which includes the run-out distance and the related hazard intensities like the height and velocity of a debris flow. In addition, as observed in the French Alps, the process of entrainment of material during the run-out can be 10-50 times in volume with respect to the initially mobilized mass triggered at the source area. The entrainment process is evidently an important factor that can further determine the magnitude and intensity of debris flows. Research on numerical modeling of debris flow entrainment is still ongoing and involves some difficulties. This is partly due to our lack of knowledge of the actual process of the uptake and incorporation of material and due the effect of entrainment on the final behavior of a debris flow. Therefore, it is important to model the effects of this key erosional process on the formation of run-outs and related intensities. In this study we analyzed a debris flow with high entrainment rates that occurred in 2003 at the Faucon catchment in the Barcelonnette Basin (Southern French Alps). The historic event was back-analyzed using the Voellmy rheology and an entrainment model imbedded in the RAMMS 2-D numerical modeling software. A sensitivity analysis of the rheological and entrainment parameters was carried out and the effects of modeling with entrainment on the debris flow run-out, height and velocity were assessed.

LOX, GOX and Pressure Relief

NASA Technical Reports Server (NTRS)

McLeod, Ken; Stoltzfus, Joel

2006-01-01

Oxygen relief systems present a serious fire hazard risk with often severe consequences. This presentation offers a risk management solution strategy which encourages minimizing ignition hazards, maximizing best materials, and utilizing good practices. Additionally, the relief system should be designed for cleanability and ballistic flow. The use of the right metals, softgoods, and lubricants, along with the best assembly techniques, is stressed. Materials should also be tested if data is not available and a full hazard analysis should be conducted in an effort to minimize risk and harm.

Aggregates from natural and recycled sources; economic assessments for construction applications; a materials flow study

USGS Publications Warehouse

Wilburn, David R.; Goonan, Thomas G.

1998-01-01

Increased amounts of recycled materials are being used to supplement natural aggregates (derived from crushed stone, sand and gravel) in road construction. An understanding of the economics and factors affecting the level of aggregates recycling is useful in estimating the potential for recycling and in assessing the total supply picture of aggregates. This investigation includes a descriptive analysis of the supply sources, technology, costs, incentives, deterrents, and market relationships associated with the production of aggregates.

Ultrahigh temperature vapor core reactor-MHD system for space nuclear electric power

NASA Technical Reports Server (NTRS)

Maya, Isaac; Anghaie, Samim; Diaz, Nils J.; Dugan, Edward T.

1991-01-01

The conceptual design of a nuclear space power system based on the ultrahigh temperature vapor core reactor with MHD energy conversion is presented. This UF4 fueled gas core cavity reactor operates at 4000 K maximum core temperature and 40 atm. Materials experiments, conducted with UF4 up to 2200 K, demonstrate acceptable compatibility with tungsten-molybdenum-, and carbon-based materials. The supporting nuclear, heat transfer, fluid flow and MHD analysis, and fissioning plasma physics experiments are also discussed.

Numerical analysis of strain localization for transversely isotropic model with non-coaxial flow rule

NASA Astrophysics Data System (ADS)

Wei, Ding; Cong-cong, Yu; Chen-hui, Wu; Zheng-yi, Shu

2018-03-01

To analyse the strain localization behavior of geomaterials, the forward Euler schemes and the tangent modulus matrix are formulated based on the transversely isotropic yield criterion with non-coaxial flow rule developed by Lade, the program code is implemented based on the user subroutine (UMAT) of ABAQUS. The influence of the material principal direction on the strain localization and the bearing capacity of the structure are investigated and analyzed. Numerical results show the validity and performance of the proposed model in simulating the strain localization behavior of geostructures.

The significance of late-stage processes in lava flow emplacement: squeeze-ups in the 2001 Etna flow field

NASA Astrophysics Data System (ADS)

Applegarth, L. J.; Pinkerton, H.; James, M. R.

2009-04-01

The general processes associated with the formation and activity of ephemeral boccas in lava flow fields are well documented (e.g. Pinkerton & Sparks 1976; Polacci & Papale 1997). The importance of studying such behaviour is illustrated by observations of the emplacement of a basaltic andesite flow at Parícutin during the 1940s. Following a pause in advance of one month, this 8 km long flow was reactivated by the resumption of supply from the vent, which forced the rapid drainage of stagnant material in the flow front region. The material extruded during drainage was in a highly plastic state (Krauskopf 1948), and its displacement allowed hot fluid lava from the vent to be transported in a tube to the original flow front, from where it covered an area of 350,000 m2 in one night (Luhr & Simkin 1993). Determining when a flow has stopped advancing, and cannot be drained in such a manner, is therefore highly important in hazard assessment and flow modelling, and our ability to do this may be improved through the examination of relatively small-scale secondary extrusions and boccas. The 2001 flank eruption of Mt. Etna, Sicily, resulted in the emplacement of a 7 km long compound `a`ā flow field over a period of 23 days. During emplacement, many ephemeral boccas were observed in the flow field, which were active for between two and at least nine days. The longer-lived examples initially fed well-established flows that channelled fresh material from the main vent. With time, as activity waned, the nature of the extruded material changed. The latest stages of development of all boccas involved the very slow extrusion of material that was either draining from higher parts of the flow or being forced out of the flow interior as changing local flow conditions pressurised parts of the flow that had been stagnant for some time. Here we describe this late-stage activity of the ephemeral boccas, which resulted in the formation of ‘squeeze-ups' of lava with a markedly different texture to that of the surrounding `a`ā flow surface. The appearance of the squeeze-up material in this flow is similar to that of the plastic lava forcibly drained from the front of the Parícutin flow. The squeeze-up features demonstrate marked morphological variation, which was found to reflect the rheology of the material being extruded, the volume of material being extruded, the extrusion rate and the geometry of the source bocca. We describe the final morphology of squeeze-ups from the 2001 flow field, which ranges from relatively fluid flows to extrusions of high-strength material that accumulated above the source bocca, forming features more akin to tumuli. Although tumulus-like in overall shape and dimensions, the morphology and inferred growth mechanisms for these structures leads to them being dubbed ‘exogenous tumuli', to distinguish them from the more familiar tumuli resulting from inflation processes, which are described elsewhere (e.g. Macdonald 1972; Walker 1991; Duncan et al. 2004). The morphological data are then used together with observations of lava surface textures and squeeze-up locations to build up a picture of flow structure and flow dynamics at the time of squeeze-up formation. The structure of the crust underlying the clinker cover can be elucidated by examining the locations in which squeeze-ups occur, as extrusions exploit zones of crustal weakness. It is found that the flow crust plays an increasingly important role in determining the locus of squeeze-ups as the flow evolves. Squeeze-ups that clearly had a high strength upon extrusion formed as a result of high overpressures in the flow interior. The extrusion of such material may represent the latter stages of activity of a long-lived bocca, or the new development of a bocca in a part of the flow that had been stagnant for some time. Examination of squeeze-up textures may help determine whether the material was transported to the extrusion site in an open or closed system, or if it was stored for a significant length of time before extrusion. Information may also be gleaned concerning the maximum crystallinity at which lava can flow, which is an important parameter in flow modelling. Evidence for a mechanism by which sufficient overpressure can be generated to extrude such material is presented.

Drying of pulverized material with heated condensible vapor

DOEpatents

Carlson, L.W.

1984-08-16

Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fines, on the outer lateral surface thereof. The cooled collection fines are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized materials then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal. 2 figs.

Municipal solid waste system analysis through energy consumption and return approach.

PubMed

Tomić, Tihomir; Schneider, Daniel Rolph

2017-12-01

Inappropriate waste management and poor resource efficiency are two of the biggest problems which European Union is trying to solve through Landfill Directive, Waste Framework Directive and Circular Economy Package by increasing recycling and reuse and reducing waste disposal. In order to meet set goals, new European Union member states must quickly change national legislature and implement appropriate solutions. In the circumstances of strong EU resource and energy dependence, decision makers need to analyse which of the considered waste management systems leads to higher overall benefits ie. which is more sustainable. The main problem in this kind of analysis is a wide range of possible technologies and the difference in inputs and outputs. Sustainability of these systems is analysed through single-score LCA based assessment, using primary energy used to produce materials and energy vectors as a common measure. To ensure reliable results, interoperability between different data sources and material flows of waste and its components are monitored. Tracking external and internal material, and energy flows enable modelling of mutual interactions between different facilities. Resulting PERI, primary energy return based index, is used for comparison of different waste management scenarios. Results show that time and legislation dependent changes have great influence on decision making related to waste management and interconnected systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analytical transport network theory to guide the design of 3-D microstructural networks in energy materials: Part 1. Flow without reactions

NASA Astrophysics Data System (ADS)

Cocco, Alex P.; Nakajo, Arata; Chiu, Wilson K. S.

2017-12-01

We present a fully analytical, heuristic model - the "Analytical Transport Network Model" - for steady-state, diffusive, potential flow through a 3-D network. Employing a combination of graph theory, linear algebra, and geometry, the model explicitly relates a microstructural network's topology and the morphology of its channels to an effective material transport coefficient (a general term meant to encompass, e.g., conductivity or diffusion coefficient). The model's transport coefficient predictions agree well with those from electrochemical fin (ECF) theory and finite element analysis (FEA), but are computed 0.5-1.5 and 5-6 orders of magnitude faster, respectively. In addition, the theory explicitly relates a number of morphological and topological parameters directly to the transport coefficient, whereby the distributions that characterize the structure are readily available for further analysis. Furthermore, ATN's explicit development provides insight into the nature of the tortuosity factor and offers the potential to apply theory from network science and to consider the optimization of a network's effective resistance in a mathematically rigorous manner. The ATN model's speed and relative ease-of-use offer the potential to aid in accelerating the design (with respect to transport), and thus reducing the cost, of energy materials.

Importance of material and friction characterisation for FE-aided process design of hybrid bevel gears

NASA Astrophysics Data System (ADS)

Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Matthias, T.

2017-10-01

Solid-forming components are often used in areas where they are subjected to very high loads. For most solid components locally divergent and sometimes contradictory requirements exist. Despite these contradictory requirements, almost exclusively monomaterials are nowadays used for the production of solid components. These components often reach their material-specific limits because of increasing demands on the products. Thus a significant increase in product quality and profitability would result from combining different materials in order to create tailored properties. In the Collaborative Research Center (CRC) 1153 "Tailored Forming" at the Leibniz Universität Hannover, this topic is investigated. The primary objective of the CRC 1153 is to develop and investigate new tailored manufacturing processes to produce reliable hybrid solid semi-finished components. In contrast to existing production processes of hybrid solid components, semi-finished workpieces in the CRC 1153 are joined before the forming phase. Thus, it will be possible to produce complex and highly stressable solid components made of different metals, which cannot be produced yet with the current used technologies. In this work the material and friction characteristics are investigated and the forming tool for the production of hybrid bevel gears made of different steel alloys (C22 and 41Cr4) is designed by numerical simulations. For this purpose, flow curves of both materials are determined by means of upsetting tests at process-related forming temperatures and strain rates. The temperature range for the forming process of the semi-finished product is determined by comparing the respective flow curves regarding similar flow stresses. Furthermore, the friction between the tool and the joining materials is investigated by means of ring upsetting tests at a process-relevant temperature. Finally, a stress analysis of the forming tools is carried out.

A new limiting procedure for discontinuous Galerkin methods applied to compressible multiphase flows with shocks and interfaces

NASA Astrophysics Data System (ADS)

Henry de Frahan, Marc T.; Varadan, Sreenivas; Johnsen, Eric

2015-01-01

Although the Discontinuous Galerkin (DG) method has seen widespread use for compressible flow problems in a single fluid with constant material properties, it has yet to be implemented in a consistent fashion for compressible multiphase flows with shocks and interfaces. Specifically, it is challenging to design a scheme that meets the following requirements: conservation, high-order accuracy in smooth regions and non-oscillatory behavior at discontinuities (in particular, material interfaces). Following the interface-capturing approach of Abgrall [1], we model flows of multiple fluid components or phases using a single equation of state with variable material properties; discontinuities in these properties correspond to interfaces. To represent compressible phenomena in solids, liquids, and gases, we present our analysis for equations of state belonging to the Mie-Grüneisen family. Within the DG framework, we propose a conservative, high-order accurate, and non-oscillatory limiting procedure, verified with simple multifluid and multiphase problems. We show analytically that two key elements are required to prevent spurious pressure oscillations at interfaces and maintain conservation: (i) the transport equation(s) describing the material properties must be solved in a non-conservative weak form, and (ii) the suitable variables must be limited (density, momentum, pressure, and appropriate properties entering the equation of state), coupled with a consistent reconstruction of the energy. Further, we introduce a physics-based discontinuity sensor to apply limiting in a solution-adaptive fashion. We verify this approach with one- and two-dimensional problems with shocks and interfaces, including high pressure and density ratios, for fluids obeying different equations of state to illustrate the robustness and versatility of the method. The algorithm is implemented on parallel graphics processing units (GPU) to achieve high speedup.

Call-Center Based Disease Management of Pediatric Asthmatics

DTIC Science & Technology

2005-04-01

study locations. Purchase peak flow meters. Prepare and reproduce patient education materials, and informed consent work sheets. Contract Oracle data...identified. Electronic peak flow meters have been purchased. Patient education materials and informed consent documents have been reproduced. A web-based...Research Center * Study population identified via military and Foundation Health databases * Electronic peak flow meters purchased * Patient education materials

Parametric Study of Carbon Nanotube Production by Laser Ablation Process

NASA Technical Reports Server (NTRS)

Arepalli, Sivaram; Nikolaev, Pavel; Holmes, William; Hadjiev, Victor; Scott, Carl

2002-01-01

Carbon nanotubes form a new class of nanomaterials that are presumed to have extraordinary mechanical, electrical and thermal properties. The single wall nanotubes (SWNTs) are estimated to be 100 times stronger than steel with 1/6th the weight; electrical carrying capacity better than copper and thermal conductivity better than diamond. Applications of these SWNTs include possible weight reduction of aerospace structures, multifunctional materials, nanosensors and nanoelectronics. Double pulsed laser vaporization process produces SWNTs with the highest percentage of nanotubes in the output material. The normal operating conditions include a green laser pulse closely followed by an infrared laser pulse. Lasers ab late a metal-containing graphite target located in a flow tube maintained in an oven at 1473K with argon flow of 100 sccm at a 500 Torr pressure. In the present work a number of production runs were carried out, changing one operating condition at a time. We have studied the effects of nine parameters, including the sequencing of the laser pulses, pulse separation times, laser energy densities, the type of buffer gas used, oven temperature, operating pressure, flow rate and inner flow tube diameters. All runs were done using the same graphite target. The collected nanotube material was characterized by a variety of analytical techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman and thermo gravimetric analysis (TGA). Results indicate trends that could be used to optimize the process and increase the efficiency of the production process.

Using Clay Models to Understand Volcanic Mudflows

ERIC Educational Resources Information Center

Laney, Eric; Mattox, Steve

2007-01-01

Gravity is a subtle but ubiquitous force that influences nearly all geologic processes from the formation of ores to the flow of glaciers and rivers. Gravity also determines the path some materials take as they flow down volcanoes. Lava flows, mudflows (also called lahars), and pyroclastic flows are three such materials. Understanding the factors…

Estimation of Rheological Properties of Viscous Debris Flow Using a Belt Conveyor

NASA Astrophysics Data System (ADS)

Hübl, J.; Steinwendtner, H.

2000-09-01

Rheological parameters of viscous debris flows are influenced by a great amount of factors and are therefore extremely difficult to estimate. Because of this uncertainties a belt conveyor (conveyor channel) was constructed to measure flow behaviour and rheological properties of natural debris flow material. The upward movement of the smooth rubberised belt between fixed lateral plastic walls causes a stationary wave relative to these bends. This special experimental design enables to study behaviour of viscous ebris flow material with maximum grain diameters up to 20 mm within several minutes and to hold measuring equipment very simple. The conveyor channel was calibrated first with Xanthan, a natural polysaccharide used as thickener in food technology, whose rheological properties are similar to viscous debris flow material. In a second step natural debris flow material was investigated. Velocities and rheological parameters were measured with varying solid concentration and slope of the channel. In cases where concentration of coarse particles exceed around 15% by volume the conveyor channel obtains an alternative to expensive commercial viscometers for determination of rheological parameters of viscous debris flows.

Cross-flow electrochemical reactor cells, cross-flow reactors, and use of cross-flow reactors for oxidation reactions

DOEpatents

Balachandran, Uthamalingam; Poeppel, Roger B.; Kleefisch, Mark S.; Kobylinski, Thaddeus P.; Udovich, Carl A.

1994-01-01

This invention discloses cross-flow electrochemical reactor cells containing oxygen permeable materials which have both electron conductivity and oxygen ion conductivity, cross-flow reactors, and electrochemical processes using cross-flow reactor cells having oxygen permeable monolithic cores to control and facilitate transport of oxygen from an oxygen-containing gas stream to oxidation reactions of organic compounds in another gas stream. These cross-flow electrochemical reactors comprise a hollow ceramic blade positioned across a gas stream flow or a stack of crossed hollow ceramic blades containing a channel or channels for flow of gas streams. Each channel has at least one channel wall disposed between a channel and a portion of an outer surface of the ceramic blade, or a common wall with adjacent blades in a stack comprising a gas-impervious mixed metal oxide material of a perovskite structure having electron conductivity and oxygen ion conductivity. The invention includes reactors comprising first and second zones seprated by gas-impervious mixed metal oxide material material having electron conductivity and oxygen ion conductivity. Prefered gas-impervious materials comprise at least one mixed metal oxide having a perovskite structure or perovskite-like structure. The invention includes, also, oxidation processes controlled by using these electrochemical reactors, and these reactions do not require an external source of electrical potential or any external electric circuit for oxidation to proceed.

An Image-based Micro-continuum Pore-scale Model for Gas Transport in Organic-rich Shale

NASA Astrophysics Data System (ADS)

Guo, B.; Tchelepi, H.

2017-12-01

Gas production from unconventional source rocks, such as ultra-tight shales, has increased significantly over the past decade. However, due to the extremely small pores ( 1-100 nm) and the strong material heterogeneity, gas flow in shale is still not well understood and poses challenges for predictive field-scale simulations. In recent years, digital rock analysis has been applied to understand shale gas transport at the pore-scale. An issue with rock images (e.g. FIB-SEM, nano-/micro-CT images) is the so-called "cutoff length", i.e., pores and heterogeneities below the resolution cannot be resolved, which leads to two length scales (resolved features and unresolved sub-resolution features) that are challenging for flow simulations. Here we develop a micro-continuum model, modified from the classic Darcy-Brinkman-Stokes framework, that can naturally couple the resolved pores and the unresolved nano-porous regions. In the resolved pores, gas flow is modeled with Stokes equation. In the unresolved regions where the pore sizes are below the image resolution, we develop an apparent permeability model considering non-Darcy flow at the nanoscale including slip flow, Knudsen diffusion, adsorption/desorption, surface diffusion, and real gas effect. The end result is a micro-continuum pore-scale model that can simulate gas transport in 3D reconstructed shale images. The model has been implemented in the open-source simulation platform OpenFOAM. In this paper, we present case studies to demonstrate the applicability of the model, where we use 3D segmented FIB-SEM and nano-CT shale images that include four material constituents: organic matter, clay, granular mineral, and pore. In addition to the pore structure and the distribution of the material constituents, we populate the model with experimental measurements (e.g. size distribution of the sub-resolution pores from nitrogen adsorption) and parameters from the literature and identify the relative importance of different physics on gas production. Overall, the micro-continuum model provides a novel tool for digital rock analysis of organic-rich shale.

Fluid permeability measurement system and method

DOEpatents

Hallman, Jr., Russell Louis; Renner, Michael John [Oak Ridge, TN

2008-02-05

A system for measuring the permeance of a material. The permeability of the material may also be derived. The system provides a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

Resource management performance in Bahrain: a systematic analysis of municipal waste management, secondary material flows and organizational aspects.

PubMed

Al Sabbagh, Maram K; Velis, Costas A; Wilson, David C; Cheeseman, Christopher R

2012-08-01

This paper presents a detailed review of municipal solid waste (MSW) and resource management in Bahrain, using the recently developed UN-Habitat city profile methodology. Performance indicators involve quantitative assessment of waste collection and sweeping, controlled disposal, materials recovery and financial sustainability together with qualitative assessment of user and provider inclusivity and institutional coherence. MSW management performance in Bahrain is compared with data for 20 other cities. The system in Bahrain is at an intermediate stage of development. A waste/material flow diagram allows visualization of the MSW system and quantifies all inputs and outputs, with the vast majority of MSW deposited in a controlled, but not engineered landfill. International comparative analysis shows that recycling and material recovery rates in Bahrain (8% wt. for domestic waste, of which 3% wt. due to informal sector) are generally lower than other cities, whereas waste quantities and generation rates at 1.1 kg capita(-1) day(-1)) are relatively high. The organic fraction (60% wt.) is comparable to that in middle- and low-income cities (50-80% wt.), although on the basis of gross domestic product Bahrain is classified as a high-income city, for which the average is generally less than 30% wt. Inclusivity in waste governance is at a medium stage as not all waste system stakeholders are considered in decision-making. While the system now appears to be financially stable, key pending issues are cost-effectiveness, improving the standards of disposal and deployment of extensive materials recovery/recycling services.

A material flow analysis on current electrical and electronic waste disposal from Hong Kong households.

PubMed

Lau, Winifred Ka-Yan; Chung, Shan-Shan; Zhang, Chan

2013-03-01

A material flow study on five types of household electrical and electronic equipment, namely television, washing machine, air conditioner, refrigerator and personal computer (TWARC) was conducted to assist the Government of Hong Kong to establish an e-waste take-back system. This study is the first systematic attempt on identifying key TWARC waste disposal outlets and trade practices of key parties involved in Hong Kong. Results from two questionnaire surveys, on local households and private e-waste traders, were used to establish the material flow of household TWARC waste. The study revealed that the majority of obsolete TWARC were sold by households to private e-waste collectors and that the current e-waste collection network is efficient and popular with local households. However, about 65,000 tonnes/yr or 80% of household generated TWARC waste are being exported overseas by private e-waste traders, with some believed to be imported into developing countries where crude recycling methods are practiced. Should Hong Kong establish a formal recycling network with tight regulatory control on imports and exports, the potential risks of current e-waste recycling practices on e-waste recycling workers, local residents and the environment can be greatly reduced. Copyright © 2012 Elsevier Ltd. All rights reserved.

Research on the Micro Sheet Stamping Process Using Plasticine as Soft Punch

PubMed Central

Wang, Xiao; Zhang, Di; Gu, Chunxing; Shen, Zongbao; Liu, Huixia

2014-01-01

Plasticine is widely used in the analysis of metal forming processes, due to its excellent material flow ability. In this study, plasticine is used as the soft punch to fabricate array micro-channels on metal sheet in the micro sheet stamping process. This is because plasticine can produce a large material flow after being subjected to force and through the material flow, the plasticine can cause the sheet to fill into the micro-channels of the rigid die, leading to the generation of micro-channels in the sheet. The distribution of array micro-channels was investigated as well as the influence of load forces on the sheet deformations. It was found that the depth of micro-channels increases as the load force increases. When the load force reaches a certain level, a crack can be observed. The micro sheet stamping process was also investigated by the method of numerical simulation. The obtained experimental and numerical results for the stamping process showed that they were in good agreement. Additionally, from the simulation results, it can be seen that the corner region of the micro-channel-shape work piece has a risk to crack due to the existence of maximum von Mises stress and significant thinning. PMID:28788668

Numerical Analysis of Convection/Transpiration Cooling

NASA Technical Reports Server (NTRS)

Glass, David E.; Dilley, Arthur D.; Kelly, H. Neale

1999-01-01

An innovative concept utilizing the natural porosity of refractory-composite materials and hydrogen coolant to provide CONvective and TRANspiration (CONTRAN) cooling and oxidation protection has been numerically studied for surfaces exposed to a high heat flux, high temperature environment such as hypersonic vehicle engine combustor walls. A boundary layer code and a porous media finite difference code were utilized to analyze the effect of convection and transpiration cooling on surface heat flux and temperature. The boundary, layer code determined that transpiration flow is able to provide blocking of the surface heat flux only if it is above a minimum level due to heat addition from combustion of the hydrogen transpirant. The porous media analysis indicated that cooling of the surface is attained with coolant flow rates that are in the same range as those required for blocking, indicating that a coupled analysis would be beneficial.

Plastic deformation history in infeed rotary swaging process

NASA Astrophysics Data System (ADS)

Liu, Yang; Herrmann, Marius; Schenck, Christian; Kuhfuss, Bernd

2017-10-01

In bulk forming processes, the net shape of a final product is achieved by plastic deformation as the material flows from the initial shape to the final shape of the workpiece. The material flow during the process is an important issue for its relationship with forging force, heat generation, microstructure transformation and energy consumption. Hence, the final properties of the product are directly influenced. Former researches showed that the material flow in the rotary swaging process is affected by different processing parameters like die angle, feeding velocity and friction condition. Thus, a profound knowledge of detailed material flow during the process is essential for a better understanding of the process. By using FEM, the material flow was investigated by the history of the plastic strain (PEEQ) development. In this study a 2D-axisymmetric model was built by using ABAQUS explicit. Both aluminum alloy (3.3206) and steel (1.0308) are studied with different feeding velocities and coefficients of friction. To achieve the development of PEEQ in different areas, the workpiece was divided into radial layers. The PEEQ history of each layer was tracked during the quasi-static forming process. Based on that, the plastic strain rate (PSR) was calculated and examined in a single stroke of the process. In that way, the material flow in different layers is presented and the material flow on the surface differs from that in the center, just the first 1/4 radial area from the surface is sensitive to different friction conditions.

Cavitation erosion prediction based on analysis of flow dynamics and impact load spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mihatsch, Michael S., E-mail: michael.mihatsch@aer.mw.tum.de; Schmidt, Steffen J.; Adams, Nikolaus A.

2015-10-15

Cavitation erosion is the consequence of repeated collapse-induced high pressure-loads on a material surface. The present paper assesses the prediction of impact load spectra of cavitating flows, i.e., the rate and intensity distribution of collapse events based on a detailed analysis of flow dynamics. Data are obtained from a numerical simulation which employs a density-based finite volume method, taking into account the compressibility of both phases, and resolves collapse-induced pressure waves. To determine the spectrum of collapse events in the fluid domain, we detect and quantify the collapse of isolated vapor structures. As reference configuration we consider the expansion ofmore » a liquid into a radially divergent gap which exhibits unsteady sheet and cloud cavitation. Analysis of simulation data shows that global cavitation dynamics and dominant flow events are well resolved, even though the spatial resolution is too coarse to resolve individual vapor bubbles. The inviscid flow model recovers increasingly fine-scale vapor structures and collapses with increasing resolution. We demonstrate that frequency and intensity of these collapse events scale with grid resolution. Scaling laws based on two reference lengths are introduced for this purpose. We show that upon applying these laws impact load spectra recorded on experimental and numerical pressure sensors agree with each other. Furthermore, correlation between experimental pitting rates and collapse-event rates is found. Locations of high maximum wall pressures and high densities of collapse events near walls obtained numerically agree well with areas of erosion damage in the experiment. The investigation shows that impact load spectra of cavitating flows can be inferred from flow data that captures the main vapor structures and wave dynamics without the need for resolving all flow scales.« less

Influence of geometry and material of insulating posts on particle trapping using positive dielectrophoresis.

PubMed

Pesch, Georg R; Du, Fei; Baune, Michael; Thöming, Jorg

2017-02-03

Insulator-based dielectrophoresis (iDEP) is a powerful particle analysis technique based on electric field scattering at material boundaries which can be used, for example, for particle filtration or to achieve chromatographic separation. Typical devices consist of microchannels containing an array of posts but large scale application was also successfully tested. Distribution and magnitude of the generated field gradients and thus the possibility to trap particles depends apart from the applied field strength on the material combination between post and surrounding medium and on the boundary shape. In this study we simulate trajectories of singe particles under the influence of positive DEP that are flowing past one single post due to an external fluid flow. We analyze the influence of key parameters (excitatory field strength, fluid flow velocity, particle size, distance from the post, post size, and cross-sectional geometry) on two benchmark criteria, i.e., a critical initial distance from the post so that trapping still occurs (at fixed particle size) and a critical minimum particle size necessary for trapping (at fixed initial distance). Our approach is fundamental and not based on finding an optimal geometry of insulating structures but rather aims to understand the underlying phenomena of particle trapping. A sensitivity analysis reveals that electric field strength and particle size have the same impact, as have fluid flow velocity and post dimension. Compared to these parameters the geometry of the post's cross-section (i.e. rhomboidal or elliptical with varying width-to-height or aspect ratio) has a rather small influence but can be used to optimize the trapping efficiency at a specific distance. We hence found an ideal aspect ratio for trapping for each base geometry and initial distance to the tip which is independent of the other parameters. As a result we present design criteria which we believe to be a valuable addition to the existing literature. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid flow cytometry analysis of antimicrobial properties of nettle powder and cranberry powder

NASA Astrophysics Data System (ADS)

Hattuniemi, Maarit; Korhonen, Johanna; Jaakkola, Mari; Räty, Jarkko; Virtanen, Vesa

2010-11-01

Both nettle (Urtica dioica) and cranberry (Vaccinium oxycoccus) are widely known to have good influence on health. The aim of this study was to investigate antimicrobial properties of nettle powder and cranberry powder against Escherichia coli (E. coli) and monitor the growth of the bacteria by a rapid flow cytometry (FCM) method. For FCM measurements samples were stained with fluorescent dyes. The inhibitory effects of plant material on growth of E. coli were estimated by comparing the results of control sample (E. coli) to E. coli samples with plant material. FCM offers both a brilliant tool to investigate the kinetics of the growth of bacterium, since subsamples can be taken from the same liquid medium during the growing period and with fluorescent dyes a rapid method to investigate viability of the bacterium.

Numerical studies of the polymer melt flow in the extruder screw channel and the forming tool

NASA Astrophysics Data System (ADS)

Ershov, S. V.; Trufanova, N. M.

2017-06-01

To date, polymer compositions based on polyethylene or PVC is widely used as insulating materials. These materials processing conjugate with a number of problems during selection of the rational extrusion regimes. To minimize the time and cost when determining the technological regime uses mathematical modeling techniques. The paper discusses heat and mass transfer processes in the extruder screw channel, output adapter and the cable head. During the study were determined coefficients for three rheological models based on obtained viscosity vs. shear rate experimental data. Also a comparative analysis of this viscosimetric laws application possibility for studying polymer melt flow during its processing on the extrusion equipment was held. As a result of numerical study the temperature, viscosity and shear rate fields in the extruder screw channel and forming tool were obtained.

Theoretical Evaluation of the Transient Response of Constant Head and Constant Flow-Rate Permeability Tests

USGS Publications Warehouse

Zhang, M.; Takahashi, M.; Morin, R.H.; Esaki, T.

1998-01-01

A theoretical analysis is presented that compares the response characteristics of the constant head and the constant flowrate (flow pump) laboratory techniques for quantifying the hydraulic properties of geologic materials having permeabilities less than 10-10 m/s. Rigorous analytical solutions that describe the transient distributions of hydraulic gradient within a specimen are developed, and equations are derived for each method. Expressions simulating the inflow and outflow rates across the specimen boundaries during a constant-head permeability test are also presented. These solutions illustrate the advantages and disadvantages of each method, including insights into measurement accuracy and the validity of using Darcy's law under certain conditions. The resulting observations offer practical considerations in the selection of an appropriate laboratory test method for the reliable measurement of permeability in low-permeability geologic materials.

Autoclave processing for composite material fabrication. 1: An analysis of resin flows and fiber compactions for thin laminate

NASA Technical Reports Server (NTRS)

Hou, T. H.

1985-01-01

High quality long fiber reinforced composites, such as those used in aerospace and industrial applications, are commonly processed in autoclaves. An adequate resin flow model for the entire system (laminate/bleeder/breather), which provides a description of the time-dependent laminate consolidation process, is useful in predicting the loss of resin, heat transfer characteristics, fiber volume fraction and part dimension, etc., under a specified set of processing conditions. This could be accomplished by properly analyzing the flow patterns and pressure profiles inside the laminate during processing. A newly formulated resin flow model for composite prepreg lamination process is reported. This model considers viscous resin flows in both directions perpendicular and parallel to the composite plane. In the horizontal direction, a squeezing flow between two nonporous parallel plates is analyzed, while in the vertical direction, a poiseuille type pressure flow through porous media is assumed. Proper force and mass balances have been made and solved for the whole system. The effects of fiber-fiber interactions during lamination are included as well. The unique features of this analysis are: (1) the pressure gradient inside the laminate is assumed to be generated from squeezing action between two adjacent approaching fiber layers, and (2) the behavior of fiber bundles is simulated by a Finitely Extendable Nonlinear Elastic (FENE) spring.

TACT 1: A computer program for the transient thermal analysis of a cooled turbine blade or vane equipped with a coolant insert. 2. Programmers manual

NASA Technical Reports Server (NTRS)

Gaugler, R. E.

1979-01-01

A computer program to calculate transient and steady state temperatures, pressures, and coolant flows in a cooled axial flow turbine blade or vane with an impingement insert is described. Coolant-side heat transfer coefficients are calculated internally in the program, with the user specifying either impingement or convection heat transfer at each internal flow station. Spent impingement air flows in a chordwise direction and is discharged through the trailing edge and through film cooling holes. The ability of the program to handle film cooling is limited by the internal flow model. Input to the program includes a description of the blade geometry, coolant-supply conditions, outside thermal boundary conditions, and wheel speed. The blade wall can have two layers of different materials, such as a ceramic thermal barrier coating over a metallic substrate. Program output includes the temperature at each node, the coolant pressures and flow rates, and the coolant-side heat transfer coefficients.

Pumping tests in nonuniform aquifers - The radially symmetric case

USGS Publications Warehouse

Butler, J.J.

1988-01-01

Traditionally, pumping-test-analysis methodology has been limited to applications involving aquifers whose properties are assumed uniform in space. This work attempts to assess the applicability of analytical methodology to a broader class of units with spatially varying properties. An examination of flow behavior in a simple configuration consisting of pumping from the center of a circular disk embedded in a matrix of differing properties is the basis for this investigation. A solution describing flow in this configuration is obtained through Laplace-transform techniques using analytical and numerical inversion schemes. Approaches for the calculation of flow properties in conditions that can be roughly represented by this simple configuration are proposed. Possible applications include a wide variety of geologic structures, as well as the case of a well skin resulting from drilling or development. Of more importance than the specifics of these techniques for analysis of water-level responses is the insight into flow behavior during a pumping test that is provided by the large-time form of the derived solution. The solution reveals that drawdown during a pumping test can be considered to consist of two components that are dependent and independent of near-well properties, respectively. Such an interpretation of pumping-test drawdown allows some general conclusions to be drawn concerning the relationship between parameters calculated using analytical approaches based on curve-matching and those calculated using approaches based on the slope of a semilog straight line plot. The infinite-series truncation that underlies the semilog analytical approaches is shown to remove further contributions of near-well material to total drawdown. In addition, the semilog distance-drawdown approach is shown to yield an expression that is equivalent to the Thiem equation. These results allow some general recommendations to be made concerning observation-well placement for pumping tests in nonuniform aquifers. The relative diffusivity of material on either side of a discontinuity is shown to be the major factor in controlling flow behavior during the period in which the front of the cone of depression is moving across the discontinuity. Though resulting from an analysis of flow in an idealized configuration, the insights of this work into flow behavior during a pumping test are applicable to a wide class of nonuniform units. ?? 1988.

Dynamic probabilistic material flow analysis of nano-SiO2, nano iron oxides, nano-CeO2, nano-Al2O3, and quantum dots in seven European regions.

PubMed

Wang, Yan; Nowack, Bernd

2018-04-01

Static environmental exposure assessment models based on material flow analysis (MFA) have previously been used to estimate flows of engineered nanomaterials (ENMs) to the environment. However, such models do not account for changes in the system behavior over time. Dynamic MFA used in this study includes the time-dependent development of the modelling system by considering accumulation of ENMs in stocks and the environment, and the dynamic release of ENMs from nano-products. In addition, this study also included regional variations in population, waste management systems, and environmental compartments, which subsequently influence the environmental release and concentrations of ENMs. We have estimated the flows and release concentrations of nano-SiO 2 , nano-iron oxides, nano-CeO 2 , nano-Al 2 O 3 , and quantum dots in the EU and six geographical sub-regions in Europe (Central Europe, Northern Europe, Southern Europe, Eastern Europe, South-eastern Europe, and Switzerland). The model predicts that a large amount of ENMs are accumulated in stocks (not considering further transformation). For example, in the EU 2040 Mt of nano-SiO 2 are stored in the in-use stock, 80,400 tonnes have been accumulated in sediments and 65,600 tonnes in natural and urban soil from 1990 to 2014. The magnitude of flows in waste management processes in different regions varies because of differences in waste handling. For example, concentrations in landfilled waste are lowest in South-eastern Europe due to dilution by the high amount of landfilled waste in the region. The flows predicted in this work can serve as improved input data for mechanistic environmental fate models and risk assessment studies compared to previous estimates using static models. Copyright © 2018 Elsevier Ltd. All rights reserved.

40 CFR 92.5 - Reference materials.

Code of Federal Regulations, 2011 CFR

2011-07-01

... § 92.113 ASTM D 1945-91, Standard Test Method for Analysis of Natural Gas by Gas Chromatography § 92... Supercritical Fluid Chromatography § 92.113 ASTM E 29-93a, Standard Practice for Using Significant Digits in....119 SAE Recommended Practice J244, Measurement of Intake Air or Exhaust Gas Flow of Diesel Engines...

Establishing Empirical Bases for Sustainability Objectives

Treesearch

Lawrence Martin

2006-01-01

The argument is made that sustainability should be construed as measurable environmental conditions, and that sustainable development strategies should be considered in terms of how well they contribute to the sustainable condition target. A case study of the Chesapeake Bay is presented to illustrate how use of Material Flow Analysis (MFA) as a basic component in the...

A QUANTITATIVE STUDY OF THE EVOLUTION OF GASES FROM ELECTRON TUBES AND MATERIALS.

DTIC Science & Technology

spectrometer, ion pumps, ionization gauges and precision orifices to measure the flow rate of individual gases. It has been used to examine several...amounts comprise about 95% of the gas evolved during cathode conversion and activation. Additional experiments in the dynamic analysis of tube processes are suggested. (Author)

Validated Test Method 1314: Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio for Constituents in Solid Materials Using An Up-Flow Percolation Column Procedure

EPA Pesticide Factsheets

Describes procedures written based on the assumption that they will be performed by analysts who are formally trained in at least the basic principles of chemical analysis and in the use of the subject technology.

Spatial-temporal diagnostics of the system of a plasma stream interacting with a surface of heat resistant material

NASA Astrophysics Data System (ADS)

Chinnov, V. F.; Sargsyan, M. A.; Gadzhiev, M. Kh; Khromov, M. A.; Kavyrshin, D. I.; Chistolinov, A. V.

2018-01-01

In an automated measuring complex using optical and spectral methods the spatial and temporal changes in the parameters and composition of nitrogen plasma jet were investigated. The plasma jet was flowing out of the nozzle of the plasma torch with 10-12 kK temperature and acting on the sample of MPG-6 graphite. Due to the heating of the sample to the temperatures of 2.5-3 kK the influence of the sublimating material of the sample on the plasma composition and temperature in the near-surface region of the sample was investigated. An original method based on the analysis of movement of optical inhomogeneities in the plasma flow was used to estimate the plasma jet velocity in the region where it interacts with the sample. The combined analysis of the results of two-positioning video recordings opens up the possibility of determining spatial-temporal distributions of the plasma jet velocities, in medium and high pressure environments, in the ranges from few to thousands of m/s and 3-15 kK temperatures.

Lunar and Planetary Science XXXV: Martian Aeolian and Mass Wasting Processes: Blowing and Flowing

NASA Technical Reports Server (NTRS)

2004-01-01

The session Martian Aeolian and Mass Wasting Processes: BLowing and Flowing included the following topics: 1) Three Decades of Martian Surface Changes; 2) Thermophysical Properties of Isidis Basin, Mars; 3) Intracrater Material in Eastern Arabia Terra: THEMIS, MOC, and MOLA Analysis of Wind-blown Deposits and Possible High-Inertia Source Material; 4) Thermal Properties of Sand from TES and THEMIS: Do Martian Dunes Make a Good Control for Thermal Inertia Calculations? 5) A Comparative Analysis of Barchan Dunes in the Intra-Crater Dune Fields and the North Polar Sand Sea; 6) Diluvial Dunes in Athabasca Valles, Mars: Morphology, Modeling and Implications; 7) Surface Profiling of Natural Dust Devils; 8) Martian Dust Devil Tracks: Inferred Directions of Movement; 9) Numerical Simulations of Anastomosing Slope Streaks on Mars; 10) Young Fans in an Equatorial Crater in Xanthe Terra, Mars; 11) Large Well-exposed Alluvual Fans in Deep Late-Noachian Craters; 12) New Evidence for the Formation of Large Landslides on Mars; and 13) What Can We Learn from the Ages of Valles Marineris Landslides on Martian Impact History?

Determination of As, Hg and Pb in herbs using slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry.

PubMed

Tai, Chia-Yi; Jiang, Shiuh-Jen; Sahayam, A C

2016-02-01

Analysis of herbs for As, Hg and Pb has been carried out using slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) with flow injection vapor generation. Slurry containing 0.5% m/v herbal powder, 0.1% m/v citric acid and 2% v/v HCl was injected into the VG-ICP-MS system for the determination of As, Hg and Pb that obviate dissolution and mineralization. Standard addition and isotope dilution methods were used for quantifications in selected herbal powders. This method has been validated by the determination of As, Hg and Pb in NIST standard reference materials SRM 1547 Peach Leaves and SRM 1573a Tomato Leaves. The As, Hg and Pb analysis results of the reference materials agreed with the certified values. The precision obtained by the reported procedure was better than 7% for all determinations. The detection limit estimated from standard addition curve was 0.008, 0.003, and 0.007 ng mL(-1) for As, Hg and Pb, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Material flow analysis of scarce metals: sources, functions, end-uses and aspects for future supply.

PubMed

Peiró, Laura Talens; Méndez, Gara Villalba; Ayres, Robert U

2013-03-19

A number of metals that are now important to the electronic industry (and others) will become much more important in the future if current trends in technology continue. Most of these metals are byproducts (or hitch-hikers) of a small number of important industrial metals (attractors). By definition, the metals in the hitch-hiker group are not mined by themselves, and thus their production is limited by the demand for the major attractors. This article presents a material flow analysis (MFA) of the complex inter-relationships between these groups of metals. First, it surveys the main sources of geologically scarce (byproduct) metals currently considered critical by one or other of several recent studies. This is followed by a detailed survey of their major functions and the quantities contained in intermediate and end-products. The purpose is to identify the sectors and products where those metals are used and stocked and thus potentially available for future recycling. It concludes with a discussion of the limitations of possible substitution and barriers to recycling.

Numerical investigations on flow dynamics of prismatic granular materials using the discrete element method

NASA Astrophysics Data System (ADS)

Hancock, W.; Weatherley, D.; Wruck, B.; Chitombo, G. P.

2012-04-01

The flow dynamics of granular materials is of broad interest in both the geosciences (e.g. landslides, fault zone evolution, and brecchia pipe formation) and many engineering disciplines (e.g chemical engineering, food sciences, pharmaceuticals and materials science). At the interface between natural and human-induced granular media flow, current underground mass-mining methods are trending towards the induced failure and subsequent gravitational flow of large volumes of broken rock, a method known as cave mining. Cave mining relies upon the undercutting of a large ore body, inducement of fragmentation of the rock and subsequent extraction of ore from below, via hopper-like outlets. Design of such mines currently relies upon a simplified kinematic theory of granular flow in hoppers, known as the ellipsoid theory of mass movement. This theory assumes that the zone of moving material grows as an ellipsoid above the outlet of the silo. The boundary of the movement zone is a shear band and internal to the movement zone, the granular material is assumed to have a uniformly high bulk porosity compared with surrounding stagnant regions. There is however, increasing anecdotal evidence and field measurements suggesting this theory fails to capture the full complexity of granular material flow within cave mines. Given the practical challenges obstructing direct measurement of movement both in laboratory experiments and in-situ, the Discrete Element Method (DEM [1]) is a popular alternative to investigate granular media flow. Small-scale DEM studies (c.f. [3] and references therein) have confirmed that movement within DEM silo flow models matches that predicted by ellipsoid theory, at least for mono-disperse granular material freely outflowing at a constant rate. A major draw-back of these small-scale DEM studies is that the initial bulk porosity of the simulated granular material is significantly higher than that of broken, prismatic rock. In this investigation, more realistic granular material geometries are simulated using the ESyS-Particle [2] DEM simulation software on cluster supercomputers. Individual grains of the granular material are represented as convex polyhedra. Initially the polyhedra are packed in a low bulk porosity configuration prior to commencing silo flow simulations. The resultant flow dynamics are markedly different to that predicted by ellipsoid theory. Initially shearing occurs around the silo outlet however rapidly shear localization in a particular direction dominates other directions, causing preferential movement in that direction. Within the shear band itself, the granular material becomes hgihly dilated however elsewhere the bulk porosity remains low. The low porosity within these regions promotes entrainment whereby large volumes of granular material interlock and begin to rotate and translate as a single rigid body. In some cases, entrainment may result in complete overturning of a large volume of material. The consequences of preferential shear localization and in particular, entrainment, for granular media flow in cave mines and natural settings (such as brecchia pipes) is a topic of ongoing research to be presented at the meeting.

The formation of granular fronts in debris flow - A combined experimental-numerical study

NASA Astrophysics Data System (ADS)

Leonardi, Alessandro; Cabrera, Miguel; Wittel, Falk K.; Kaitna, Roland; Mendoza, Miller; Wu, Wei; Herrmann, Hans J.

2015-04-01

Granular fronts are amongst the most spectacular features of debris flows, and are also one of the reasons why such events are associated with a strong destructive power. They are usually believed to be the result of the convective mechanism of the debris flow, combined with internal size segregation of the grains. However, the knowledge about the conditions leading to the formation of a granular front is not up to date. We present a combined study with experimental and numerical features that aims at providing insight into the phenomenon. A stationary, long-lived avalanche is created within a rotating drum. In order to mimic the composition of an actual debris flow, the material is composed by a mixture of a plastic fluid, obtained with water and kaolin powder, and a collection of monodisperse spherical particles heavier than the fluid. Tuning the material properties and the drum settings, we are able to reproduce and control the formation of a granular front. To gain insight into the internal mechanism, the same scenario is replicated in a numerical environment, using a coupling technique between a discrete solver for the particles, the Discrete Element Method, and a continuum solver for the plastic fluid, the Lattice-Boltzmann Method. The simulations compare well with the experiments, and show the internal reorganization of the material transport. The formation of a granular front is shown to be favored by a higher drum rotational speed, which in turn forces a higher shear rate on the particles, breaks their internal organization, and contrasts their natural tendency to settle. Starting from dimensional analysis, we generalize the obtained results and are able to draw implications for debris flow research.

Monitoring bedload entrainment and transport in snowmelt-dominated forest streams of the Columbia Mountains, Canada

NASA Astrophysics Data System (ADS)

Green, Kim; Brardinoni, Francesco; Alila, Younes

2014-05-01

We monitor bedload transport and water discharge at six stations in two forested headwater streams of the Columbia Mountains, Canada. The monitoring network of sediment traps is designed to examine the effects of channel bed texture, and the influence of alluvial (i.e., step pools, and riffle pools) and semi-alluvial morphologies (i.e., boulder cascades and forced step pools) on bedload entrainment and transport. Results suggest that patterns of bedload entrainment are influenced by flow resistance while the value of the critical dimensionless shear stress for mobilization of the surface D50 varies due to channel gradient, grain sheltering effects and, to a less extent, flow resistance. Regardless of channel morphology we observe: (i) equal-threshold entrainment for all mobile grains in channels with high grain and/or form resistance; and (ii) initial equal-threshold entrainment of calibers ≤ 22mm, and subsequent size-selective entrainment of coarser material in channels with low form resistance (e.g. riffle pool). Scaled fractional analysis reveals that in reaches with high flow resistance most bedload transport occurs in partial mobility fashion relative to the available bed material and that only material finer than 16mm attains full mobility during over-bank flows. Equal mobility transport for a wider range of grain sizes is achieved in reaches with reduced flow resistance. Evaluation of bedload rating curves across sites identifies that grain effects predominate with respect to bedload flux whereas morphological effects (i.e. form resistance) play a secondary role. Application of selected empirical formulae developed in steep alpine channels present variable success in predicting transport rates in the study reaches.

Rock Failure Analysis Based on a Coupled Elastoplastic-Logarithmic Damage Model

NASA Astrophysics Data System (ADS)

Abdia, M.; Molladavoodi, H.; Salarirad, H.

2017-12-01

The rock materials surrounding the underground excavations typically demonstrate nonlinear mechanical response and irreversible behavior in particular under high in-situ stress states. The dominant causes of irreversible behavior are plastic flow and damage process. The plastic flow is controlled by the presence of local shear stresses which cause the frictional sliding. During this process, the net number of bonds remains unchanged practically. The overall macroscopic consequence of plastic flow is that the elastic properties (e.g. the stiffness of the material) are insensitive to this type of irreversible change. The main cause of irreversible changes in quasi-brittle materials such as rock is the damage process occurring within the material. From a microscopic viewpoint, damage initiates with the nucleation and growth of microcracks. When the microcracks length reaches a critical value, the coalescence of them occurs and finally, the localized meso-cracks appear. The macroscopic and phenomenological consequence of damage process is stiffness degradation, dilatation and softening response. In this paper, a coupled elastoplastic-logarithmic damage model was used to simulate the irreversible deformations and stiffness degradation of rock materials under loading. In this model, damage evolution & plastic flow rules were formulated in the framework of irreversible thermodynamics principles. To take into account the stiffness degradation and softening on post-peak region, logarithmic damage variable was implemented. Also, a plastic model with Drucker-Prager yield function was used to model plastic strains. Then, an algorithm was proposed to calculate the numerical steps based on the proposed coupled plastic and damage constitutive model. The developed model has been programmed in VC++ environment. Then, it was used as a separate and new constitutive model in DEM code (UDEC). Finally, the experimental Oolitic limestone rock behavior was simulated based on the developed model. The irreversible strains, softening and stiffness degradation were reproduced in the numerical results. Furthermore, the confinement pressure dependency of rock behavior was simulated in according to experimental observations.

Flows of Selected Hazardous Materials by Rail

DOT National Transportation Integrated Search

1990-03-01

This report reviews the hazardous materials rail traffic of 33 selected hazardous materials commoditites or commodity groups in 1986, a relatively typical recent year. The flow of the selected commodities by rail are characterized and their geographi...

Materials Flow and Sustainability

USGS Publications Warehouse

Sznopek, John L.; Brown, William M.

1998-01-01

Materials extracted from the Earth are necessary to produce our most fundamental needs – food, clothing, and shelter. Materials are needed to maintain and improve our standard of living. Understanding the whole system of materials flow, from source to ultimate disposition, can help us better manage the use of natural resources and protect the environment.

Effect of two different bleaching regimens on the gloss of tooth colored restorative materials.

PubMed

Yalcin, Filiz; Gürgan, Sevil

2005-05-01

Vital tooth bleaching with peroxide is one of the most common cosmetic procedures in dentistry and can be accomplished using a variety of methods or regimens. Recently, new generation of tooth color restorative materials were introduced to market. The purpose of this in vitro study was to determine the gloss changes of three different tooth color restorative materials: Flowable composite (Filtek Flow/3M), packable composite (Filtek P60/3M) and ormocer (Definite/DEGUSSA) after two different bleaching regimens (Vivastyle/VIVADENT) and (Crest Professional Whitestrips/PROCTER and GAMBLE). 16 specimens 30 x 30 x 2 mm size were fabricated from each restorative material. After gloss values were measured with gloss meter, at two different angles of illumination (20 and 60 degrees ), 10% carbamide peroxide (Vivastyle) was applied for 2 h per day for fourteen days to the half of the specimens while 6.5% hydrogen peroxide strip bands (Crest Professional Whitestrips) were applied to the remaining eight of the specimens for 30 min twice daily for 14 days. During the test period the specimens were stored in 37 degrees C and 100% relative humidity. At the end of bleaching regimen the gloss measurements were repeated and the data were subjected to statistical analysis. The Wilcoxon Signed Rank Test analysis revealed that the gloss values were affected by both bleaching regimens (P=0.012). Whitestrips decreased the gloss values of Filtek P60 (at 20 and 60 degrees , P<0.001) and Filtek Flow (at 20 degrees , P=0.05 and at 60 degrees , P=0.05) significantly compared to Vivastyle, while the gloss values of Definite did not show any significant change between Vivastyle and Whitestrips application (at 20 degrees P=0.279; at 60 degrees , P=0.279, Mann-Whitney U Test). The gloss values of materials were significantly different before (at 20 degrees P<0.001; at 60 degrees , P=0.003) and after bleaching (at 20 degrees P<0.05; at 60 degrees , P<0.05) with the highest value of Filtek Flow followed Filtek P60 and then by Definite (Kruskal Wallis test). As the gloss of tooth colored restorative materials could be affected by bleaching regimens, it is necessary to consider the type of the material before starting the treatment.

Clustering in the stellar abundance space

NASA Astrophysics Data System (ADS)

Boesso, R.; Rocha-Pinto, H. J.

2018-03-01

We have studied the chemical enrichment history of the interstellar medium through an analysis of the n-dimensional stellar abundance space. This work is a non-parametric analysis of the stellar chemical abundance space. The main goal is to study the stars from their organization within this abundance space. Within this space, we seek to find clusters (in a statistical sense), that is, stars likely to share similar chemo-evolutionary history, using two methods: the hierarchical clustering and the principal component analysis. We analysed some selected abundance surveys available in the literature. For each sample, we labelled the group of stars according to its average abundance curve. In all samples, we identify the existence of a main enrichment pattern of the stars, which we call chemical enrichment flow. This flow is set by the structured and well-defined mean rate at which the abundances of the interstellar medium increase, resulting from the mixture of the material ejected from the stars and stellar mass-loss and interstellar medium gas. One of the main results of our analysis is the identification of subgroups of stars with peculiar chemistry. These stars are situated in regions outside of the enrichment flow in the abundance space. These peculiar stars show a mismatch in the enrichment rate of a few elements, such as Mg, Si, Sc and V, when compared to the mean enrichment rate of the other elements of the same stars. We believe that the existence of these groups of stars with peculiar chemistry may be related to the accretion of planetary material on to stellar surfaces or may be due to production of the same chemical element by different nucleosynthetic sites.

Assessing environmental risks for high intensity agriculture using the material flow analysis method--a case study of the Dongting Lake basin in South Central China.

PubMed

Yin, Guanyi; Liu, Liming; Yuan, Chengcheng

2015-07-01

This study primarily examined the assessment of environmental risk in high intensity agricultural areas. Dongting Lake basin was taken as a case study, which is one of the major grain producing areas in China. Using data obtained from 1989 to 2012, we applied Material Flow Analysis (MFA) to show the material consumption, pollutant output and production storage in the agricultural-environmental system and assessed the environmental risk index on the basis of the MFA results. The results predicted that the status of the environmental quality of the Dongting Lake area is unsatisfactory for the foreseeable future. The direct material input (DMI) declined by 13.9%, the domestic processed output (DPO) increased by 28.21%, the intensity of material consumption (IMC) decreased by 36.7%, the intensity of material discharge (IMD) increased by 10%, the material productivity (MP) increased by 27 times, the environmental efficiency (EE) increased by 15.31 times, and the material storage (PAS) increased by 0.23%. The DMI and DPO was higher at rural places on the edge of cities, whereas the risk of urban agriculture has arisen due to the higher increasing rate of DMI and DPO in cities compared with the counties. The composite environmental risk index increased from 0.33 to 0.96, indicating that the total environmental risk changed gradually but seriously during the 24 years assessed. The driving factors that affect environmental risk in high intensity agriculture can be divided into five classes: social, economic, human, natural and disruptive incidents. This study discussed a number of effective measures for protecting the environment while ensuring food production yields. Additional research in other areas and certain improvements of this method in future studies may be necessary to develop a more effective method of managing and controlling agricultural-environmental interactions.

Beam Flutter and Energy Harvesting in Internal Flow

NASA Astrophysics Data System (ADS)

Tosi, Luis Phillipe; Colonius, Tim; Sherrit, Stewart; Lee, Hyeong Jae

2017-11-01

Aeroelastic flutter, largely studied for causing engineering failures, has more recently been used as a means of extracting energy from the flow. Particularly, flutter of a cantilever or an elastically mounted plate in a converging-diverging flow passage has shown promise as an energy harvesting concept for internal flow applications. The instability onset is observed as a function of throat velocity, internal wall geometry, fluid and structure material properties. To enable these devices, our work explores features of the fluid-structure coupled dynamics as a function of relevant nondimensional parameters. The flutter boundary is examined through stability analysis of a reduced order model, and corroborated with numerical simulations at low Reynolds number. Experiments for an energy harvester design are qualitatively compared to results from analytical and numerical work, suggesting a robust limit cycle ensues due to a subcritical Hopf bifurcation. Bosch Corporation.

A Jamming Phase Diagram for Pressing Polymers

NASA Astrophysics Data System (ADS)

Teng, Chao; Zhang, Zexin; Wang, Xiaoliang; Xue, Gi; Nanjing University Team; Soochow University Collaboration

2011-03-01

Molecular glasses begin to flow when they are heated. Other glassy systems, such as dense foams, emulsions, colloidal suspensions and granular materials, begin to flow when subjected to sufficiently large stresses. The equivalence of these two routes to flow is a basic tenet of jamming, a conceptual means of unifying glassy behavior in a swath of disordered, dynamical arrested systems. However, a full understanding of jamming transition for polymers remains elusive. By controlling the packing densities of polymer glasses, we found that polymer glasses could once flow under cold-pressing at temperatures well below its calorimetric glass transition temperature (Tg). The thermomechanical analysis (TMA) results confirmed that Tg changed with density as well as the applied stress, which is exactly what to be expected within the jamming picture. We propose a jamming phase diagram for polymers based on our laboratory experiments.

Mass flow and energy balance plus economic analysis of a full-scale biogas plant in the rice-wine-pig system.

PubMed

Li, Jiang; Kong, Chuixue; Duan, Qiwu; Luo, Tao; Mei, Zili; Lei, Yunhui

2015-10-01

This paper presents mass flow and energy balance as well as an economic analysis for a biogas plant in a rice-wine-pig system at a practical rather than laboratory scale. Results showed feeding amount was 65.30 t d(-1) (total solid matter (TSM) 1.3%) for the normal temperature continuous stirred tank reactor (CSTR), and 16.20 t d(-1) (TSM 8.4%) for the mesophilic CSTR. The digestion produced 80.50 t d(-1) of mass, with 76.41 t d(-1) flowing into rice fields and 4.49 t d(-1) into composting. Energy consumption of this plant fluctuated with seasons, and surplus energy was 823, 221 kWh/year. Thus, biogas plant was critical for material recycling and energy transformation of this agro-ecosystem. The economic analysis showed that the payback time of the plant was 10.9 years. It also revealed application of biogas as a conventional energy replacement would be attractive for a crop-wine-livestock ecosystem with anaerobic digestion of manure. Copyright © 2015 Elsevier Ltd. All rights reserved.

Jet-controlled freeze valve for use in a glass melter

DOEpatents

Routt, Kenneth R.

1986-09-02

A drain valve for use in a furnace for the melting of thermoplastic material. The furnace includes a drain cavity formed in its bottom for withdrawing a flow of thermoplastic material. The drain valve includes a flow member which include a flow tube having an inlet and outlet for the material, and coaxially disposed concentric tubular members defining annuli surrounding the flow tube. The tubular members include heating and cooling means for the flow tube. The flow member is adapted to fit in mating relationship in the drain cavity. A freeze valve member is disposed adjacent the outlet of the flow member. The freeze valve member includes heating means and has a plurality of air jets adapted to direct streams of pressurized air at the outlet to control the flow of thermoplastic material through the flow members. The drain valve can also be used in a furnace of glass melting that includes a drain cavity for withdrawing molten glass from the furnace. The drain valve includes a flow tube member having an inlet and outlet, and having heating and cooling means. The tube member is adapted to fit in mating relationship with the drain cavity. A freeze valve member is disposed at the outlet of the flow tube member. The freeze valve member includes heating means and has a plurality of air jets adapted to direct a stream of pressurized air at the outlet to control the flow of glass through the flow tube member.

Jet-controlled freeze valve for use in a glass melter

DOEpatents

Routt, Kenneth R.

1986-01-01

A drain valve for use in a furnace for the melting of thermoplastic material. The furnace includes a drain cavity formed in its bottom for withdrawing a flow of thermoplastic material. The drain valve includes a flow member which include a flow tube having an inlet and outlet for the material, and coaxially disposed concentric tubular members defining annuli surrounding the flow tube. The tubular members include heating and cooling means for the flow tube. The flow member is adapted to fit in mating relationship in the drain cavity. A freeze valve member is disposed adjacent the outlet of the flow member. The freeze valve member includes heating means and has a plurality of air jets adapted to direct streams of pressurized air at the outlet to control the flow of thermoplastic material through the flow members. The drain valve can also be used in a furnace of glass melting that includes a drain cavity for withdrawing molten glass from the furnace. The drain valve includes a flow tube member having an inlet and outlet, and having heating and cooling means. The tube member is adapted to fit in mating relationship with the drain cavity. A freeze valve member is disposed at the outlet of the flow tube member. The freeze valve member includes heating means and has a plurality of air jets adapted to direct a stream of pressurized air at the outlet to control the flow of glass through the flow tube member.

Grain-size-yield stress relationship: Analysis and computation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyers, M.A.; Benson, D.J.; Fu, H.H.

1999-07-01

The seminal contributions of Julia Weertman to the understanding of the mechanical properties of nanocrystalline materials will be briefly outlined. A constitutive equation predicting the effect of grain size on the yield stress of metals, based on the model proposed by M.A. Meyers and E. Ashworth, is discussed and extended to the nanocrystalline regime. At large grain sizes, it has the Hall-Petch form, and in the nanocrystalline domain the slope gradually decreases until it asymptotically approaches the flow stress of the grain boundaries. The material is envisaged as a composite, comprised of the grain interior, with flow stress {sigma}{sub fB},more » and grain boundary work-hardened layer, with flow stress {sigma}{sub fGB}. Three principal factors contribute to the grain-boundary hardening: (1) the grain boundaries act as barriers to plastic flow; (2) the grain boundaries act as dislocation sources; and (3) elastic anisotropy causes additional stresses in grain-boundary surroundings. The predictions of this model are compared with experimental measurements over the mono, micro, and nanocrystalline domains. Computational predictions are made of plastic flow as a function of grain size incorporating elastic and plastic anisotropy as well as differences of dislocation accumulation rate in grain boundary regions and grain interiors. This is the first plasticity calculation that accounts for grain size effects in a physically-based manner. 58 refs., 7 figs., 1 tab.« less

A tunable optofluidic circular liquid fiber

NASA Astrophysics Data System (ADS)

Li, Lei; Wu, Wei; Shi, Yang; Gong, Enze; Yang, Yi

2016-01-01

This paper presents a tunable optofluidic circular liquid fiber through the numerical simulation. Fiber is a significant optical device and has been widely applied on optical fiber communication. But the fiber based solid has limited tunability. Compared to solid fiber, the fiber based liquid material is relatively infrequent. Cause for the liquid optical device has more freedom tunable properties than solid counterpart, it has attracted more interest. The traditional optofluidic waveguide is designed like a sandwich in planar channel. This two-dimensional (2D) structure liquid waveguide will face huge transmission loss in the perpendicular direction of the flow streams. In this paper, a curving microchannel is designed inside the microchip to produce centrifugal effect. Two different liquids are injected into the chip by external pumps. In a particular situation, the core flow will be totally surrounded by the cladding flow. So the liquid can form an optical waveguide. Its structure is similar to an optical fiber which high refractive index (RI) liquid is core of the waveguide and the low RI liquid is cladding of the waveguide. Profit from the reconfigurability of liquid material, this liquid fiber has excellent tunability. The diameter of the core flow can be tuned in a wider range by changing the volume ratio of the flows through the finite element analysis. It is predictable that such a tunable liquid fiber may find wider applications in lab-on-a-chip systems and integrated optical devices.

MaTrace: tracing the fate of materials over time and across products in open-loop recycling.

PubMed

Nakamura, Shinichiro; Kondo, Yasushi; Kagawa, Shigemi; Matsubae, Kazuyo; Nakajima, Kenichi; Nagasaka, Tetsuya

2014-07-01

Even for metals, open-loop recycling is more common than closed-loop recycling due, among other factors, to the degradation of quality in the end-of-life (EoL) phase. Open-loop recycling is subject to loss of functionality of original materials, dissipation in forms that are difficult to recover, and recovered metals might need dilution with primary metals to meet quality requirements. Sustainable management of metal resources calls for the minimization of these losses. Imperative to this is quantitative tracking of the fate of materials across different stages, products, and losses. A new input-output analysis (IO) based model of dynamic material flow analysis (MFA) is presented that can trace the fate of materials over time and across products in open-loop recycling taking explicit consideration of losses and the quality of scrap into account. Application to car steel recovered from EoL vehicles (ELV) showed that after 50 years around 80% of the steel is used in products, mostly buildings and civil engineering (infrastructure), with the rest mostly resided in unrecovered obsolete infrastructure and refinery losses. Sensitivity analysis was conducted to evaluate the effects of changes in product lifespan, and the quality of scrap.

Gradient isolator for flow field of fuel cell assembly

DOEpatents

Ernst, W.D.

1999-06-15

Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions. 4 figs.

Gradient isolator for flow field of fuel cell assembly

DOEpatents

Ernst, William D.

1999-01-01

Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions.

Characterization and Detailed Analysis of Regression Behavior for HTPB Solid Fuels Containing High Aluminum Loadings

NASA Technical Reports Server (NTRS)

Kibbey, Timothy P.; Cortopassi, Andrew C.; Boyer, Eric C.

2017-01-01

NASA Marshall Space Flight Center's Materials and Processes Department, with support from the Propulsion Systems Department, has renewed the development and maintenance of a hybrid test bed for exposing ablative thermal protection materials to an environment similar to that seen in solid rocket motors (SRM). The Solid Fuel Torch (SFT), operated during the Space Shuttle program, utilized gaseous oxygen for oxidizer and an aluminized hydroxyl-terminated polybutadiene (HTPB) fuel grain to expose a converging section of phenolic material to a 400 psi, 2-phase flow combustion environment. The configuration allows for up to a 2 foot long, 5 inch diameter fuel grain cartridge. Wanting to now test rubber insulation materials with a turn-back feature to mimic the geometry of an aft dome being impinged by alumina particles, the throat area has now been increased by several times to afford flow similarity. Combined with the desire to maintain a higher operating pressure, the oxidizer flow rate is being increased by a factor of 10. Out of these changes has arisen the need to characterize the fuel/oxidizer combination in a higher mass flux condition than has been previously tested at MSFC, and at which the literature has little to no reporting as well. For (especially) metalized fuels, hybrid references have pointed out possible dependence of fuel regression rate on a number of variables: mass flux, G - oxidizer only (G0), or - total mass flux (Gtot), Length, L, Pressure, P, and Diameter, D.

Layered/Pancake-like Ejecta on Ceres: Inferring the Composition and Mechanical Properties of the Cerean Surface through Modeling of Ejecta Emplacement

NASA Astrophysics Data System (ADS)

Hughson, K.; Russell, C. T.; Schmidt, B. E.; Chilton, H.; Scully, J. E. C.; Sizemore, H. G.; Byrne, S.; Platz, T.; Raymond, C. A.

2017-12-01

During the Survey, High Altitude Mapping Orbit, and Low Altitude Mapping Orbit phases of the primary mission Dawn's Framing Camera observed a multitude of globally distributed lobate deposits. These flows were broadly interpreted as either similar to ice-cored/ice-cemented flows (Type 1 flows) on Earth and Mars, long run-out terrestrial or martian landslides (Type 2 flows), or highly mobile fluidized ejecta-like deposits (Type 3 flows) (Buczckowski et al., 2016; Schmidt et al., 2017). The Type 3 flows are morphologically similar to layered/pancake ejecta found on Mars and Ganymede where they are thought to be caused by impacts into ground ice rich substrates (Mouginis-Mark, 1979; Boyce et al., 2010). We assess the effects of target material strength, sliding friction, and vapor entrainment on the production of these features by comparing the ejecta mobility (EM: the ratio of the radius of the ejecta blanket to the radius of the parent crater) values for all Type 3 cerean flows to a ballistic/kinematic sliding model similar to the one developed by Weiss et al. (2014) to model EM for impacts into a variety of ground ice rich substrates of differing volatile content on Mars. Initial results suggest that, in order for these features to form, the cerean surface requires a large coefficient of sliding friction (>0.1), and that significant amounts of water be vaporized during impact. However, the model does not tightly constrain the strength of the target material (best-fit values range from granite-like to unconsolidated-sand-like). These results are consistent with a largely dry, rough, and thin surface layer underlain by material rich in pore-filling ground ice, even at low latitudes. Additionally, before the Fall Meeting we will attempt to constrain the thickness of the ice-poor surface layer. This will be done through a combined analysis of model results and morphometric parameters of individual Type 3 flows. Future implementation of this model will further incorporate compositional and geophysical knowledge attained from Dawn in order to better constrain the strength of the cerean surface.

Arc-Heater Facility for Hot Hydrogen Exposure of Nuclear Thermal Rocket Materials

NASA Technical Reports Server (NTRS)

Litchford, Ron J.; Foote, John P.; Wang,Ten-See; Hickman, Robert; Panda, Binayak; Dobson, Chris; Osborne, Robin; Clifton, Scooter

2006-01-01

A hyper-thermal environment simulator is described for hot hydrogen exposure of nuclear thermal rocket material specimens and component development. This newly established testing capability uses a high-power, multi-gas, segmented arc-heater to produce high-temperature pressurized hydrogen flows representative of practical reactor core environments and is intended to serve. as a low cost test facility for the purpose of investigating and characterizing candidate fueUstructura1 materials and improving associated processing/fabrication techniques. Design and development efforts are thoroughly summarized, including thermal hydraulics analysis and simulation results, and facility operating characteristics are reported, as determined from a series of baseline performance mapping tests.

Flow Cytometric Methods for Circulating Tumor Cell Isolation and Molecular Analysis.

PubMed

Bhagwat, Neha; Carpenter, Erica L

2017-01-01

Circulating tumor cells provide a non-invasive source of tumor material that can be valuable at all stages of disease management, including screening and early diagnosis, monitoring response to therapy, identifying therapeutic targets, and assessing development of drug resistance. Cells isolated from the blood of cancer patients can be used for phenotypic analysis, tumor genotyping, transcriptional profiling, as well as for ex vivo culture of isolated cells. There are a variety of novel technologies currently being developed for the detection and analysis of rare cells in circulation of cancer patients. Flow cytometry is a powerful cell analysis platform that is increasingly being used in this field of study due to its relatively high throughput and versatility with respect to the large number of commercially available antibodies and fluorescent probes available to translational and clinical researchers. More importantly, it offers the ability to easily recover viable cells with high purity that are suitable for downstream molecular analysis, thus making it an attractive technology for cancer research and as a diagnostic tool.

Efficacy of ProTaper Retreatment System in Root Canals Obturated with Gutta-Percha Using Two Different Sealers and GuttaFlow

PubMed Central

Siotia, Jaya; Acharya, Shashi Rashmi; Gupta, Sunil Kumar

2011-01-01

Objective. To compare the efficacy of ProTaper retreatment files in removing three different obturating materials. Study Design. Forty-five human, single-rooted premolars were divided into three experimental groups. Group 1 was obturated with gutta-percha and AH Plus sealer, Group 2 was obturated with gutta-percha and zinc oxide eugenol sealer, and Group 3 was obturated with GuttaFlow. Retreatment was done using the ProTaper universal rotary retreatment files. Root halves were visualized using magnifying loops at 3X magnification and optical stereomicroscope at 10X magnification. Images were analyzed using AutoCAD 2004 software to calculate area of the remaining debris in the canal. For statistical analysis were used variance test and ANOVA. Results. Total debris/canal area ratio between the three groups showed a statistically significant difference (P < 0.001). Conclusion. ProTaper retreatment system did not produce completely clean canals in any of the groups. However, it had the best efficacy towards removing silicon based obturating material GuttaFlow. PMID:22114598

The application of an MPM-MFM method for simulating weapon-target interaction.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, X.; Zou, Q.; Zhang, D. Z.

2005-01-01

During the past two decades, Los Alamos National Laboratory (LANL) has developed computational algorithms and software for analysis of multiphase flow suitable for high-speed projectile penetration of metallic and nonmetallic materials, using a material point method (MPM)-multiphase flow method (MFM). Recently, ACTA has teamed with LANL to advance a computational algorithm for simulating complex weapon-target interaction for penetrating and exploding munitions, such as tank rounds and artillery shells, as well as non-exploding kinetic energy penetrators. This paper will outline the mathematical basis for the MPM-MFM method as implemented in LANL's CartaBlanca code. CartaBlanca, written entirely in Java using object-oriented design,more » is used to solve complex problems involving (a) failure and penetration of solids, (b) heat transfer, (c) phase change, (d) chemical reactions, and (e) multiphase flow. We will present its application to the penetration of a steel target by a tungsten cylinder and compare results with time-resolved experimental data published by Anderson, et. al., Int. J. Impact Engng., Vol. 16, No. 1, pp. 1-18, 1995.« less

Composition and luminescence studies of InGaN epilayers grown at different hydrogen flow rates

NASA Astrophysics Data System (ADS)

Taylor, E.; Fang, F.; Oehler, F.; Edwards, P. R.; Kappers, M. J.; Lorenz, K.; Alves, E.; McAleese, C.; Humphreys, C. J.; Martin, R. W.

2013-06-01

Indium gallium nitride (InxGa1 - xN) is a technologically important material for many optoelectronic devices, including LEDs and solar cells, but it remains a challenge to incorporate high levels of InN into the alloy while maintaining sample quality. A series of InGaN epilayers was grown with different hydrogen flow rates (0-200 sccm) and growth temperatures (680-750 °C) to obtain various InN fractions and bright emission in the range 390-480 nm. These 160-nm thick epilayers were characterized through several compositional techniques (wavelength dispersive x-ray spectroscopy, x-ray diffraction, Rutherford backscattering spectrometry) and cathodoluminescence hyperspectral imaging. The compositional analysis with the different techniques shows good agreement when taking into account compositional gradients evidenced in these layers. The addition of small amounts of hydrogen to the gas flow at lower growth temperatures is shown to maintain a high surface quality and luminescence homogeneity. This allowed InN fractions of up to ˜16% to be incorporated with minimal peak energy variations over a mapped area while keeping a high material quality.

Geophysical Investigations at Hidden Dam, Raymond, California Flow Simulations

USGS Publications Warehouse

Minsley, Burke J.; Ikard, Scott

2010-01-01

Numerical flow modeling and analysis of observation-well data at Hidden Dam are carried out to supplement recent geophysical field investigations at the site (Minsley and others, 2010). This work also is complementary to earlier seepage-related studies at Hidden Dam documented by Cedergren (1980a, b). Known seepage areas on the northwest right abutment area of the downstream side of the dam was documented by Cedergren (1980a, b). Subsequent to the 1980 seepage study, a drainage blanket with a sub-drain system was installed to mitigate downstream seepage. Flow net analysis provided by Cedergren (1980a, b) suggests that the primary seepage mechanism involves flow through the dam foundation due to normal reservoir pool elevations, which results in upflow that intersects the ground surface in several areas on the downstream side of the dam. In addition to the reservoir pool elevations and downstream surface topography, flow is also controlled by the existing foundation geology as well as the presence or absence of a horizontal drain in the downstream portion of the dam. The current modeling study is aimed at quantifying how variability in dam and foundation hydrologic properties influences seepage as a function of reservoir stage. Flow modeling is implemented using the COMSOL Multiphysics software package, which solves the partially saturated flow equations in a two-dimensional (2D) cross-section of Hidden Dam that also incorporates true downstream topography. Use of the COMSOL software package provides a more quantitative approach than the flow net analysis by Cedergren (1980a, b), and allows for rapid evaluation of the influence of various parameters such as reservoir level, dam structure and geometry, and hydrogeologic properties of the dam and foundation materials. Historical observation-well data are used to help validate the flow simulations by comparing observed and predicted water levels for a range of reservoir elevations. The flow models are guided by, and discussed in the context of, the geophysical work (Minsley and others, 2010) where appropriate.

Experimental visualization of solutes transport in two-dimensional saturated permeable media

NASA Astrophysics Data System (ADS)

Muñoz, Edinsson; Herrera, Paulo

2017-04-01

Mass transport processes in groundwater flows control transport of contaminants or other dissolved substances. A good characterization of transport processes should allow, for example, the optimization of remediation systems or the prediction of natural attenuation or dilution of pollutants in aquifers. Several previous studies have highlighted the role of heterogeneity in transverse mixing processes, which may be enhanced by the convergence of streamlines due to the presence of high permeability materials. The convergence of streamlines increases the concentration gradients in the direction transverse to the flow, which results in greater transverse mixing and natural dilution. This mixing makes possible the occurrence of chemical reactions between species dissolved in groundwater of different origin. We used image analysis techniques to characterize experiments that replicate the transport of a conservative tracer in two types of quasi 2-D homogeneous and heterogeneous saturated permeable media. The experiments were carried out in an acrylic glass tank, 85 cm long, 16 cm wide and 1 cm thick. We simulated flow conditions found in confined aquifers by imposing a vertical flow fed by a peristaltic pump that injected water at eight points at the bottom of the tank, while we controlled the outflow through the top boundary by using a constant head reservoir. We filled the tank with glass beads with mean diameter 0.05 cm to model the matrix material of the porous media and we used glass beads of 0.2 cm to create a high permeability inclusion to study the effect of heterogeneity on transverse mixing. After steady-state of flux was reached, we injected a conservative tracer (Blue Brilliant) only at the two central ports, while clean water continued flowing through the other six ports. We took digital pictures of the steady-state plume and analyzed the concentration of the tracer along perpendicular to the mean flow fringes, using a piecewise linear model to convert light intensity to concentrations in every pixel. We compared the concentrations calculated with image analysis to theoretical and numerical solutions. We also compared the estimated concentration distributions for a homogeneous and a heterogeneous experiments using as quantitative index the flow-related dilution index (Rolle et al., 2009). We conclude that in the heterogeneous case the dilution index was 1.5 times greater than in the homogeneous case, which confirms that heterogeneity due to inclusions of permeable materials can increase the transverse mixing or dilution of a conservative tracer.

Nicotine, acetanilide and urea multi-level2H-,13C- and15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry

USGS Publications Warehouse

Schimmelmann, A.; Albertino, A.; Sauer, P.E.; Qi, H.; Molinie, R.; Mesnard, F.

2009-01-01

Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the S values of these reference materials should bracket the isotopic range of samples with unknown S values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for ??13C and ??13N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: ??2Hnicotine -162 to -45%o, ??13Cnicotine -30.05 to +7.72%, ?? 15Nnicotine -6.03 to +33.62%; ??15N acetanilide +1-18 to +40.57%; ??13Curea -34.13 to +11.71%, ??15Nurea +0.26 to +40.61% (recommended ?? values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as the first organic nitrogen stable isotope reference materials for GC-IRMS that are available with different ??13N values. Comparative ??13C and ??15N on-line EA-IRMS data from 14 volunteering laboratories document the usefulness and reliability of acetanilides and ureas as EA-IRMS reference materials.

Experimental study on the signs of particulate structures formation in annular geometry of rapid granular shear flows

NASA Astrophysics Data System (ADS)

Ritvanen, J.; Jalali, P.

2009-06-01

Rapid granular shear flow is a classical example in granular materials which exhibits both fluid-like and solid-like behaviors. Another interesting feature of rapid granular shear flows is the formation of ordered structures upon shearing. Certain amount of granular material, with uniform size distribution, is required to be loaded in the container in order to shear it under stable conditions. This work concerns the experimental study of rapid granular shear flows in annular Couette geometry. The flow is induced by continuous rotation of the plate over the top of the granular bed in an annulus. The compressive pressure, driving torque, instantaneous bed height from three symmetric locations and rotational speed of the shearing plate are measured. The annulus has a capacity of up to 15 kg of spherical steel balls of 3 mm in diameter. Rapid shear flow experiments are performed in one compressive force and rotation rate. The sensitivity of fluctuations is then investigated by different means through monodisperse packing. In this work, we present the results of the experiments showing how the flow properties depend on the amount of loaded granular material which is varied by small amounts between different experiments. The flow can exist in stable (fixed behavior) and unstable (time-dependent behavior) regimes as a function of the loaded material. We present the characteristics of flow to detect the formation of any additional structured layer in the annulus. As a result, an evolution graph for the bed height has been obtained as material is gradually added. This graph shows how the bed height grows when material increases. Using these results, the structure inside the medium can be estimated at extreme stable and unstable conditions.

Modeling and simulation of clutch pressure plate casting using alternate materials

NASA Astrophysics Data System (ADS)

Madhuraj, H. N.; Bharath, M. R.

2018-04-01

Clutch Pressure Plate is a stress bearing component in the clutch assembly. Cast iron alloys like FG300, G2500 are commonly used for clutch pressure plate castings. These materials have high compressive strength, low tensile strength & no ductility but these cost high for the manufacturers. There is a need for alternate material so as to reduce cost, defects in castings without losing the life and effectiveness of the clutch plate. The work carried out here is modeling the clutch pressure plate using CAD tool. And then the casting process is simulated by casting simulation for fluid flow and solidification analysis by trying alternate material. Here the castability of the alternate material En-Gjs-400-15 and the commonly used material FG300 for the clutch pressure plate component is analyzed by designing and optimizing a proper gating system.

Granular flows in constrained geometries

NASA Astrophysics Data System (ADS)

Murthy, Tejas; Viswanathan, Koushik

Confined geometries are widespread in granular processing applications. The deformation and flow fields in such a geometry, with non-trivial boundary conditions, determine the resultant mechanical properties of the material (local porosity, density, residual stresses etc.). We present experimental studies of deformation and plastic flow of a prototypical granular medium in different nontrivial geometries- flat-punch compression, Couette-shear flow and a rigid body sliding past a granular half-space. These geometries represent simplified scaled-down versions of common industrial configurations such as compaction and dredging. The corresponding granular flows show a rich variety of flow features, representing the entire gamut of material types, from elastic solids (beam buckling) to fluids (vortex-formation, boundary layers) and even plastically deforming metals (dead material zone, pile-up). The effect of changing particle-level properties (e.g., shape, size, density) on the observed flows is also explicitly demonstrated. Non-smooth contact dynamics particle simulations are shown to reproduce some of the observed flow features quantitatively. These results showcase some central challenges facing continuum-scale constitutive theories for dynamic granular flows.

Information systems for material flow management in construction processes

NASA Astrophysics Data System (ADS)

Mesároš, P.; Mandičák, T.

2015-01-01

The article describes the options for the management of material flows in the construction process. Management and resource planning is one of the key factors influencing the effectiveness of construction project. It is very difficult to set these flows correctly. The current period offers several options and tools to do this. Information systems and their modules can be used just for the management of materials in the construction process.

Paper recycling framework, the "Wheel of Fiber".

PubMed

Ervasti, Ilpo; Miranda, Ruben; Kauranen, Ilkka

2016-06-01

At present, there is no reliable method in use that unequivocally describes paper industry material flows and makes it possible to compare geographical regions with each other. A functioning paper industry Material Flow Account (MFA) that uses uniform terminology and standard definitions for terms and structures is necessary. Many of the presently used general level MFAs, which are called frameworks in this article, stress the importance of input and output flows but do not provide a uniform picture of material recycling. Paper industry is an example of a field in which recycling plays a key role. Additionally, terms related to paper industry recycling, such as collection rate, recycling rate, and utilization rate, are not defined uniformly across regions and time. Thus, reliably comparing material recycling activity between geographical regions or calculating any regional summaries is difficult or even impossible. The objective of this study is to give a partial solution to the problem of not having a reliable method in use that unequivocally describes paper industry material flows. This is done by introducing a new material flow framework for paper industry in which the flow and stage structure supports the use of uniform definitions for terms related to paper recycling. This new framework is termed the Detailed Wheel of Fiber. Copyright © 2016 Elsevier Ltd. All rights reserved.

Accounting for the Material Stock of Nations

PubMed Central

Fishman, Tomer; Schandl, Heinz; Tanikawa, Hiroki; Walker, Paul; Krausmann, Fridolin

2014-01-01

National material stock (MS) accounts have been a neglected field of analysis in industrial ecology, possibly because of the difficulty in establishing such accounts. In this research, we propose a novel method to model national MS based on historical material flow data. This enables us to avoid the laborious data work involved with bottom-up accounts for stocks and to arrive at plausible levels of stock accumulation for nations. We apply the method for the United States and Japan to establish a proof of concept for two very different cases of industrial development. Looking at a period of 75 years (1930–2005), we find that per capita MS has been much higher in the United States for the entire period, but that Japan has experienced much higher growth rates throughout, in line with Japan's late industrial development. By 2005, however, both Japan and the United States arrive at a very similar level of national MS of 310 to 375 tonnes per capita, respectively. This research provides new insight into the relationship between MS and flows in national economies and enables us to extend the debate about material efficiency from a narrow perspective of throughput to a broader perspective of stocks. PMID:25505368

Assessing the stretch-blow moulding FE simulation of PET over a large process window

NASA Astrophysics Data System (ADS)

Nixon, J.; Menary, G. H.; Yan, S.

2017-10-01

Injection stretch blow moulding has been extensively researched for numerous years and is a well-established method of forming thin-walled containers. This paper is concerned with validating the finite element analysis of the stretch-blow-moulding (SBM) process in an effort to progress the development of injection stretch blow moulding of poly(ethylene terephthalate). Extensive data was obtained experimentally over a wide process window accounting for material temperature, air flow rate and stretch-rod speed while capturing cavity pressure, stretch-rod reaction force, in-mould contact timing and material thickness distribution. This data was then used to assess the accuracy of the correlating FE simulation constructed using ABAQUS/Explicit solver and an appropriate user-defined viscoelastic material subroutine. Results reveal that the simulation was able to pick up the general trends of how the pressure, reaction force and in-mould contact timings vary with the variation in preform temperature and air flow rate. Trends in material thickness were also accurately predicted over the length of the bottle relative to the process conditions. The knowledge gained from these analyses provides insight into the mechanisms of bottle formation, subsequently improving the blow moulding simulation and potentially providing a reduction in production costs.

Accounting for the Material Stock of Nations.

PubMed

Fishman, Tomer; Schandl, Heinz; Tanikawa, Hiroki; Walker, Paul; Krausmann, Fridolin

2014-05-01

National material stock (MS) accounts have been a neglected field of analysis in industrial ecology, possibly because of the difficulty in establishing such accounts. In this research, we propose a novel method to model national MS based on historical material flow data. This enables us to avoid the laborious data work involved with bottom-up accounts for stocks and to arrive at plausible levels of stock accumulation for nations. We apply the method for the United States and Japan to establish a proof of concept for two very different cases of industrial development. Looking at a period of 75 years (1930-2005), we find that per capita MS has been much higher in the United States for the entire period, but that Japan has experienced much higher growth rates throughout, in line with Japan's late industrial development. By 2005, however, both Japan and the United States arrive at a very similar level of national MS of 310 to 375 tonnes per capita, respectively. This research provides new insight into the relationship between MS and flows in national economies and enables us to extend the debate about material efficiency from a narrow perspective of throughput to a broader perspective of stocks.

3-D trajectory model for MDT using micro-spheres implanted within large blood vessels

NASA Astrophysics Data System (ADS)

Choomphon-anomakhun, Natthaphon; Natenapit, Mayuree

2016-09-01

Implant assisted magnetic drug targeting (IA-MDT) using ferromagnetic spherical targets implanted within large blood vessels and subjected to a uniform externally applied magnetic field (H0) has been investigated and reported for the first time. The capture areas (As) of magnetic drug carrier particles (MDCPs) were determined from the analysis of particle trajectories simulated from equations of motion. Then, the effects of various parameters, such as types of ferromagnetic materials in the targets and MDCPs, blood flow rates, mass fraction of the ferromagnetic material in the MDCPs, average radii of MDCPs (Rp) and the strength of H0 on the As were obtained. Furthermore, the effects of saturation magnetization of the ferromagnetic materials in the MDCPs and within the targets on the As were analyzed. After this, the suitable strengths of H0 and Rp for IA-MDT designs were reported. Dimensionless As, ranging from 2 to 7, was obtained with Rp ranging from 500 to 2500 nm, μ0H0 less than 0.8 T and a blood flow rate of 0.1 m s-1. The target-MDCP materials considered are iron-iron, iron-magnetite and SS409-magnetite, respectively.

Effects of composition of grains of debris flow on its impact force

NASA Astrophysics Data System (ADS)

Tang, jinbo; Hu, Kaiheng; Cui, Peng

2017-04-01

Debris flows compose of solid material with broad size distribution from fine sand to boulders. Impact force imposed by debris flows is a very important issue for protection engineering design and strongly influenced by their grain composition. However, this issue has not been studied in depth and the effects of grain composition not been considered in the calculation of the impact force. In this present study, the small-scale flume experiments with five kinds of compositions of grains for debris flow were carried out to study the effect of the composition of grains of debris flow on its impact force. The results show that the impact force of debris flow increases with the grain size, the hydrodynamic pressure of debris flow is calibrated based on the normalization parameter dmax/d50, in which dmax is the maximum size and d50 is the median size. Furthermore, a log-logistic statistic distribution could be used to describe the distribution of magnitude of impact force of debris flow, where the mean and the variance of the present distribution increase with grain size. This distribution proposed in the present study could be used to the reliability analysis of structures impacted by debris flow.

Falkner-Skan Boundary Layer Flow of a Sisko Fluid

NASA Astrophysics Data System (ADS)

Khan, Masood; Shahzad, Azeem

2012-09-01

In this paper, we investigate the steady boundary layer flow of a non-Newtonian fluid, represented by a Sisko fluid, over a wedge in a moving fluid. The equations of motion are derived for boundary layer flow of an incompressible Sisko fluid using appropriate similarity variables. The governing equations are reduced to a single third-order highly nonlinear ordinary differential equation in the dimensionless stream function, which is then solved analytically using the homotopy analysis method. Some important parameters have been discussed by this study, which include the power law index n, the material parameter A, the wedge shape factor b, and the skin friction coefficient Cf. A comprehensive study is made between the results of the Sisko and the power-law fluids.

Granular flow: Dry and wet

NASA Astrophysics Data System (ADS)

Mitarai, N.; Nakanishi, H.

2012-04-01

Granular material is a collection of macroscopic particles that are visible with naked eyes. The non-equilibrium nature of the granular materials makes their rheology quite different from that of molecular systems. In this minireview, we present the unique features of granular materials focusing on the shear flow of dry granular materials and granule-liquid mixture.

Energy efficient window and skylight assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howe, W.C. Jr.

1986-03-25

A totally self-contained apparatus is described for use as a window or skylight assembly, and adapted for simultaneously controlling the amount of both sunlight and air admitted into a building. The apparatus consists of: a head member and a sill member; a first sheet of material through which sunlight can pass, the first sheet of material forming a major portion of the exterior surface of the apparatus and being mounted between the head and sill members; a second sheet of material through which sunlight can pass, the second sheet of material being spaced from the first sheet of material themore » second sheet of material forming a major portion of the interior surface of the window apparatus and being mounted between the head and sill members; first and second window jams positioned between the first and second sheets of material and extending from the head member to the sill member so as to form an essentially enclosed air flow channel; means, positioned in the air flow channel, for regulating the amount of sunlight passing through the apparatus; and ventilation means for directing air through the air flow channel, and comprising a motor-driven fan mounted within the air flow channel at one end thereof so as to circulate air through the air flow channel together with a plurality of apertures disposed in the head and sill members for placing the air flow channel in communication with the interior and exterior of the building and means for selectively opening and closing the apertures whereby air may selectively flow from one of (a) the outside to the inside of the building, (b) from the inside to the outside of the building, (c) from the inside of the building through the air flow channel and back to the inside of the building and (d) from the outside of the building through the air flow channel and back to the outside of the building.« less

Quasi-dynamic Material Flow Analysis applied to the Austrian Phosphorus cycle

NASA Astrophysics Data System (ADS)

Zoboli, Ottavia; Rechberger, Helmut

2013-04-01

Phosphorus (P) is one of the key elements that sustain life on earth and that allow achieving the current high levels of food production worldwide. It is a non-renewable resource, without any existing substitute. Because of its current dissipative use by mankind and to its very slow geochemical cycle, this resource is rapidly depleting and it is strongly connected to the problem of ensuring food security. Moreover P is also associated to important environmental problems. Its extraction often generates hazardous wastes, while its accumulation in water bodies can lead to eutrophication, with consequent severe ecological damages. It is therefore necessary to analyze and understand in detail the system of P, in regard to its use and management, to identify the processes that should be targeted in order to reduce the overall consumption of this resource. This work aims at establishing a generic quasi-dynamic model, which describes the Austrian P-budget and which allows investigating the trends of P use in the past, but also selected future scenarios. Given the importance of P throughout the whole anthropogenic metabolism, the model is based on a comprehensive system that encompasses several economic sectors, from agriculture and animal husbandry to industry, consumption and waste and wastewater treatment. Furthermore it includes the hydrosphere, to assess the losses of P into water bodies, due to the importance of eutrophication problems. The methodology applied is Material Flow Analysis (MFA), which is a systemic approach to assess and balance the stocks and flows of a material within a system defined in space and time. Moreover the model is integrated in the software STAN, a freeware tailor-made for MFA. Particular attention is paid to the characteristics and the quality of the data, in order to include data uncertainty and error propagation in the dynamic balance.

Home-made online hyphenation of pressurized liquid extraction, turbulent flow chromatography, and high performance liquid chromatography, Cistanche deserticola as a case study.

PubMed

Song, Qingqing; Li, Jun; Liu, Xiao; Zhang, Yuan; Guo, Liping; Jiang, Yong; Song, Yuelin; Tu, Pengfei

2016-03-18

Incompatibility between the conventional pressurized liquid extraction (PLE) devices and high performance liquid chromatography (HPLC) extensively hinders direct and green chemical analysis of herbal materials. Herein, a facile PLE module was configured, and then it was online hyphenated with HPLC via a turbulent flow chromatography (TFC) column. Regarding PLE module, a long PEEK tube (0.13 × 1000 mm) was employed to generate desired pressure (approximately 13.0 MPa) when warm acidic water (70 °C) was delivered as extraction solvent at a high flow rate (2.5 mL/min), and a hollow guard column (3.0 × 4.0 mm) was implemented to hold crude materials. Effluent was collected from the outlet of PEEK tube, concentrated, and subjected onto HPLC coupled with hybrid ion trap-time of flight mass spectrometer to assess the extraction efficiency and also to profile the chemical composition of Cistanche deserticola (CD) that is honored as "Ginseng of the desert". Afterwards, a TFC column was introduced to accomplish online transmission of low molecule weight components from PLE module to HPLC coupled with diode array detection, and two electronic 6-port/2-channel valves were in charge of alternating the whole system between extraction (0-3.0 min) and elution (3.0-35.0 min) phases. Quantitative method was developed and validated for simultaneous determination of eight primary phenylethanoid glycosides in CD using online PLE-TFC-HPLC. All findings demonstrated that the home-made platform is advantageous at direct chemical analysis, as well as time-, solvent-, and material-savings, suggesting a robust tool for chemical fingerprinting of herbs. Copyright © 2016 Elsevier B.V. All rights reserved.

Fleet Sizing of Automated Material Handling Using Simulation Approach

NASA Astrophysics Data System (ADS)

Wibisono, Radinal; Ai, The Jin; Ratna Yuniartha, Deny

2018-03-01

Automated material handling tends to be chosen rather than using human power in material handling activity for production floor in manufacturing company. One critical issue in implementing automated material handling is designing phase to ensure that material handling activity more efficient in term of cost spending. Fleet sizing become one of the topic in designing phase. In this research, simulation approach is being used to solve fleet sizing problem in flow shop production to ensure optimum situation. Optimum situation in this research means minimum flow time and maximum capacity in production floor. Simulation approach is being used because flow shop can be modelled into queuing network and inter-arrival time is not following exponential distribution. Therefore, contribution of this research is solving fleet sizing problem with multi objectives in flow shop production using simulation approach with ARENA Software

Construction demolition wastes, Waelz slag and MSWI bottom ash: a comparative technical analysis as material for road construction.

PubMed

Vegas, I; Ibañez, J A; San José, J T; Urzelai, A

2008-01-01

The objective of the study is to analyze the technical suitability of using secondary materials from three waste flows (construction and demolition waste (CDW), Waelz slag and municipal solid waste incineration (MSWI) bottom ash), under the regulations and standards governing the use of materials for road construction. A detailed technical characterization of the materials was carried out according to Spanish General Technical Specifications for Road Construction (PG3). The results show that Waelz slag can be adequate for using in granular structural layers, while CDW fits better as granular material in roadbeds. Likewise, fresh MSWI bottom ash can be used as roadbed material as long as it does not contain a high concentration of soluble salts. This paper also discusses the adequacy of using certain traditional test methods for natural soils when characterizing secondary materials for use as aggregates in road construction.

RADIOPACITY OF RESTORATIVE MATERIALS USING DIGITAL IMAGES

PubMed Central

Salzedas, Leda Maria Pescinini; Louzada, Mário Jefferson Quirino; de Oliveira, Antonio Braz

2006-01-01

The radiopacity of esthetic restorative materials has been established as an important requirement, improving the radiographic diagnosis. The aim of this study was to evaluate the radiopacity of six restorative materials using a direct digital image system, comparing them to the dental tissues (enamel-dentin), expressed as equivalent thickness of aluminum (millimeters of aluminum). Five specimens of each material were made. Three 2-mm thick longitudinal sections were cut from an intact extracted permanent molar tooth (including enamel and dentin). An aluminum step wedge with 9 steps was used. The samples of different materials were placed on a phosphor plate together with a tooth section, aluminum step wedge and metal code letter, and were exposed using a dental x-ray unit. Five measurements of radiographic density were obtained from each image of each item assessed (restorative material, enamel, dentin, each step of the aluminum step wedge) and the mean of these values was calculated. Radiopacity values were subsequently calculated as equivalents of aluminum thickness. Analysis of variance (ANOVA) indicated significant differences in radiopacity values among the materials (P<0.0001). The radiopacity values of the restorative materials evaluated were, in decreasing order: TPH, F2000, Synergy, Prisma Flow, Degufill, Luxat. Only Luxat had significantly lower radiopacity values than dentin. One material (Degufill) had similar radiopacity values to enamel and four (TPH, F2000, Synergy and Prisma Flow) had significantly higher radiopacity values than enamel. In conclusion, to assess the adequacy of posterior composite restorations it is important that the restorative material to be used has enough radiopacity, in order to be easily distinguished from the tooth structure in the radiographic image. Knowledge on the radiopacity of different materials helps professionals to select the most suitable material, along with other properties such as biocompatibility, adhesion and esthetic. PMID:19089047

Influence of bed material entrainment and non-Newtonian rheology on turbulent geophysical flows dynamics. Numerical study

NASA Astrophysics Data System (ADS)

Eglit, M. E.; Yakubenko, A. E.; Yakubenko, T. A.

2017-10-01

This paper deals with the mathematical and numerical modeling of the propagation stage of geophysical gravity-driven flows, such as snow avalanches, mudflows, and rapid landslides. New mathematical models are presented which are based on full, not-depth-averaged equations of mechanics of continuous media. The models account for three important issues: non-Newtonian rheology of the moving material, entrainment of the bed material by the flow, and turbulence. The main objective is to investigate the effect of these three factors on the flow dynamics and on the value of the entrainment rate. To exclude the influence of many other factors, e.g., the complicated slope topography, only the motion down a long uniform slope with a constant inclination angle is studied numerically. Moreover, the entire flow from the front to the rear area was not modeled, but only its middle part where the flow is approximately uniform in length. One of the qualitative results is that in motion along homogeneous slope the mass entrainment increases the flow velocity and depth while the entrainment rate at large time tends to become constant which depends on the physical properties of the flow and the underlying material but not on the current values of the flow velocity and depth.

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

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

Recent Glaciers on Mars: Description and Solar System Perspective

NASA Astrophysics Data System (ADS)

Kargel, J. S.

2001-11-01

Active or recently active ice deposits occur on Mars at middle and high latitudes in fretted terrain, around massifs in highlands east of Hellas and in southern Argyre, on crater walls in the highlands, and in the south polar cap. Most mid-latitude icy flows are debris covered, apparently stagnant, and eroded by partial sublimation. Others are scarred by fresh crevasses and gullies, thus suggesting recent deformation and surface melting. Erosional features include a variety of small-scale relief elements due mainly to sublimation, but sublimation has not obliterated evidence of flow. Similar to terrestrial glaciers in many respects, there are also notable differences, especially in the nature of accumulation. Deformation of the south polar cap is indicated by folding, boudinage, strike-slip or normal faulting, forebulge tectonics near scarps, and thrust faulting. The north polar cap locally also exhibits flow indicators. The south cap's glacial features suggest interbedding of two or more types of ice of differing volatility and rheology, plus a locally deforming surficial dry-ice cap overlying the other materials. Major ice types may include two (or more) of the following, in order of highest to lowest mechanical strength: CO2 clathrate hydrate, water ice, water ice containing traces of liquid-soluble salts, water ice containing traces of solid-soluble acids, and CO2 ice; dust is another variable. Within our Solar System, the closest geomorphic analog to icy Martian flows are Earth's alpine glaciers, rock glaciers, and continental ice sheets, though key differences are apparent. If made dominantly of water ice, important and recent climatic shifts seem to be implicated. Ice-flow landforms also occur on some outer planet satellites; among them are Io, Europa, Enceladus, Ariel, and Triton. Volatile flows on these bodies may involve diverse materials, such as sulfur, water ice, hydrated salts, ammonia-water ices, and nitrogen ice. Most of these would not be suitable materials on Mars. This work was funded by grants from the NASA Mars Data Analysis Program.

Isolation of Cardiomyocyte Nuclei from Post-mortem Tissue

PubMed Central

Bergmann, Olaf; Jovinge, Stefan

2012-01-01

Identification of cardiomyocyte nuclei has been challenging in tissue sections as most strategies rely only on cytoplasmic marker proteins1. Rare events in cardiac myocytes such as proliferation and apoptosis require an accurate identification of cardiac myocyte nuclei to analyze cellular renewal in homeostasis and in pathological conditions2. Here, we provide a method to isolate cardiomyocyte nuclei from post mortem tissue by density sedimentation and immunolabeling with antibodies against pericentriolar material 1 (PCM-1) and subsequent flow cytometry sorting. This strategy allows a high throughput analysis and isolation with the advantage of working equally well on fresh tissue and frozen archival material. This makes it possible to study material already collected in biobanks. This technique is applicable and tested in a wide range of species and suitable for multiple downstream applications such as carbon-14 dating3, cell-cycle analysis4, visualization of thymidine analogues (e.g. BrdU and IdU)4, transcriptome and epigenetic analysis. PMID:22805241

Augmented Topological Descriptors of Pore Networks for Material Science.

PubMed

Ushizima, D; Morozov, D; Weber, G H; Bianchi, A G C; Sethian, J A; Bethel, E W

2012-12-01

One potential solution to reduce the concentration of carbon dioxide in the atmosphere is the geologic storage of captured CO2 in underground rock formations, also known as carbon sequestration. There is ongoing research to guarantee that this process is both efficient and safe. We describe tools that provide measurements of media porosity, and permeability estimates, including visualization of pore structures. Existing standard algorithms make limited use of geometric information in calculating permeability of complex microstructures. This quantity is important for the analysis of biomineralization, a subsurface process that can affect physical properties of porous media. This paper introduces geometric and topological descriptors that enhance the estimation of material permeability. Our analysis framework includes the processing of experimental data, segmentation, and feature extraction and making novel use of multiscale topological analysis to quantify maximum flow through porous networks. We illustrate our results using synchrotron-based X-ray computed microtomography of glass beads during biomineralization. We also benchmark the proposed algorithms using simulated data sets modeling jammed packed bead beds of a monodispersive material.

Space Systems - Safety and Compatibility of Materials - Method to Determine the Ignition Susceptibility of Materials or Components to Particle Impact

NASA Technical Reports Server (NTRS)

Hirsch, David B.

2011-01-01

The scope of this International Technical Specification is to provide a method to determine the ignition susceptibility of materials and components to particle impact. The method can be used to determine the conditions at which ignition and consumption of a specimen material occurs when impacted by single or multiple particles entrained in a flow of gaseous oxygen (GOX). Alternatively, the method can be used to determine if a specific material or component is subject to ignition and sustained combustion in a given flow environment when impacted by single or multiple particles entrained in a flow of GOX.

An incremental analysis of a deep drawing steel’s material behaviour undergoing the predeformation using drawbeads

NASA Astrophysics Data System (ADS)

Schmid, H.; Suttner, S.; Merklein, M.

2017-09-01

Nowadays lightweight design in metal forming processes leads to complex deep drawing geometries, which can cause multiple damages. Therefore, drawbeads are one way to regulate and control material flow during the forming process. Not only in research, but also in industrial practice, it could be determined that material is work hardened passing drawbead geometries. It particularly means when material is pre-deformed with tensile and alternating bending loads. This incident also gives the opportunity to utilize it in a reasonable way if examined properly. To investigate these findings, a process oriented and comprehensive analysis of the material behaviour during these forming operations is needed. In this paper, sheet metal strips are linearly drawn through a drawbead and stopped after passing the drawbead. Within this forming operation, the material undergoes non-linear straining before reaching the in-plane position again. Here, the process will be stopped to investigate a permanent strengthening local along the sheet thickness. Therefore, microhardness measurements are realized before and after passing the drawbead. Because of its common use and its wide known material data, a deep drawing steel DC will be used for these studies. Additionally, the strategy is applied to advanced high strength steel.

On continuous and discontinuous approaches for modeling groundwater flow in heterogeneous media using the Numerical Manifold Method: Model development and comparison

NASA Astrophysics Data System (ADS)

Hu, Mengsu; Wang, Yuan; Rutqvist, Jonny

2015-06-01

One major challenge in modeling groundwater flow within heterogeneous geological media is that of modeling arbitrarily oriented or intersected boundaries and inner material interfaces. The Numerical Manifold Method (NMM) has recently emerged as a promising method for such modeling, in its ability to handle boundaries, its flexibility in constructing physical cover functions (continuous or with gradient jump), its meshing efficiency with a fixed mathematical mesh (covers), its convenience for enhancing approximation precision, and its integration precision, achieved by simplex integration. In this paper, we report on developing and comparing two new approaches for boundary constraints using the NMM, namely a continuous approach with jump functions and a discontinuous approach with Lagrange multipliers. In the discontinuous Lagrange multiplier method (LMM), the material interfaces are regarded as discontinuities which divide mathematical covers into different physical covers. We define and derive stringent forms of Lagrange multipliers to link the divided physical covers, thus satisfying the continuity requirement of the refraction law. In the continuous Jump Function Method (JFM), the material interfaces are regarded as inner interfaces contained within physical covers. We briefly define jump terms to represent the discontinuity of the head gradient across an interface to satisfy the refraction law. We then make a theoretical comparison between the two approaches in terms of global degrees of freedom, treatment of multiple material interfaces, treatment of small area, treatment of moving interfaces, the feasibility of coupling with mechanical analysis and applicability to other numerical methods. The newly derived boundary-constraint approaches are coded into a NMM model for groundwater flow analysis, and tested for precision and efficiency on different simulation examples. We first test the LMM for a Dirichlet boundary and then test both LMM and JFM for an idealized heterogeneous model, comparing the numerical results with analytical solutions. Then we test both approaches for a heterogeneous model and compare the results of hydraulic head and specific discharge. We show that both approaches are suitable for modeling material boundaries, considering high accuracy for the boundary constraints, the capability to deal with arbitrarily oriented or complexly intersected boundaries, and their efficiency using a fixed mathematical mesh.

Mass, energy and material balances of SRF production process. Part 2: SRF produced from construction and demolition waste.

PubMed

Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

2014-11-01

In this work, the fraction of construction and demolition waste (C&D waste) complicated and economically not feasible to sort out for recycling purposes is used to produce solid recovered fuel (SRF) through mechanical treatment (MT). The paper presents the mass, energy and material balances of this SRF production process. All the process streams (input and output) produced in MT waste sorting plant to produce SRF from C&D waste are sampled and treated according to CEN standard methods for SRF. Proximate and ultimate analysis of these streams is performed and their composition is determined. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. By mass balance means the overall mass flow of input waste material stream in the various output streams and material balances mean the mass flow of components of input waste material stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. The results from mass balance of SRF production process showed that of the total input C&D waste material to MT waste sorting plant, 44% was recovered in the form of SRF, 5% as ferrous metal, 1% as non-ferrous metal, and 28% was sorted out as fine fraction, 18% as reject material and 4% as heavy fraction. The energy balance of this SRF production process showed that of the total input energy content of C&D waste material to MT waste sorting plant, 74% was recovered in the form of SRF, 16% belonged to the reject material and rest 10% belonged to the streams of fine fraction and heavy fraction. From the material balances of this process, mass fractions of plastic (soft), paper and cardboard, wood and plastic (hard) recovered in the SRF stream were 84%, 82%, 72% and 68% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC) and rubber material was found in the reject material stream. Streams of heavy fraction and fine fraction mainly contained non-combustible material (such as stone/rock, sand particles and gypsum material). Copyright © 2014 Elsevier Ltd. All rights reserved.

Surfactants and Desensitizing Wax Substitutes for TNT-Based Systems.

DTIC Science & Technology

1994-10-01

materials having dispersion (London or van der Waals) forces only. The concept thus had to be refined to take into account additional intermolecular...The column head pressure should have been set to produce a convenient column flow (-l to 5 ml/min) as determined by Van Demmeter plots. 8. Place...current OSHA criteria 2 200 Volatility, Approximate GC Neut . 3 hours at Carbon Typo Distillation Range No. 163 C Clay/SIlica Gel Analysis, Mass % Analysis

NanoRelease: Pilot interlaboratory comparison of a ...

EPA Pesticide Factsheets

A major use of multi-walled carbon nanotubes (MWCNTs) is as functional fillers embedded in a solid matrix, such as plastics or coatings. Weathering and abrasion of the solid matrix during use can lead to environmental releases of the MWCNTs. Here we focus on a protocol to identify and quantify the primary release induced by weathering, and assess reproducibility, transferability, and sensitivity towards different materials and uses. We prepared 132 specimens of two polymer-MWCNT composites containing the same grade of MWCNTs used in earlier OECD hazard assessments but without UV stabilizer. We report on a pilot inter-laboratory comparison (ILC) with four labs (two US and two EU) aging by UV and rain, then shipping for analysis. Two labs (one US and one EU) conducted the release sampling and analysis by Transmission Electron Microscopy (TEM), Inductively Coupled Plasma- Mass Spectrometry (ICP-MS), Ultraviolet–Visible Spectroscopy (UV–Vis), Analytical Ultracentrifugation (AUC), and Asymmetric Flow Field Flow Fractionation (AF4). We compare results between aging labs, between analysis labs and between materials. Surprisingly, we found quantitative agreement between analysis labs for TEM, ICP-MS, UV–Vis; low variation between aging labs by all methods; and consistent rankings of release between TEM, ICP-MS, UV–Vis, AUC. Significant disagreement was related primarily to differences in aging, but even these cases remained within a factor of two. Published in t

Sinuous Flow in Cutting of Metals

NASA Astrophysics Data System (ADS)

Yeung, Ho; Viswanathan, Koushik; Udupa, Anirudh; Mahato, Anirban; Chandrasekar, Srinivasan

2017-11-01

Using in situ high-speed imaging, we unveil details of a highly unsteady plastic flow mode in the cutting of annealed and highly strain-hardening metals. This mesoscopic flow mode, termed sinuous flow, is characterized by repeated material folding, large rotation, and energy dissipation. Sinuous flow effects a very large shape transformation, with local strains of ten or more, and results in a characteristic mushroomlike surface morphology that is quite distinct from the well-known morphologies of metal-cutting chips. Importantly, the attributes of this unsteady flow are also fundamentally different from other well-established unsteady plastic flows in large-strain deformation, like adiabatic shear bands. The nucleation and development of sinuous flow, its dependence on material properties, and its manifestation across material systems are demonstrated. Plastic buckling and grain-scale heterogeneity are found to play key roles in triggering this flow at surfaces. Implications for modeling and understanding flow stability in large-strain plastic deformation, surface quality, and preparation of near-strain-free surfaces by cutting are discussed. The results point to the inadequacy of the widely used shear-zone models, even for ductile metals.

Positive feedback and momentum growth during debris-flow entrainment of wet bed sediment

USGS Publications Warehouse

Iverson, R.M.; Reid, M.E.; Logan, M.; LaHusen, R.G.; Godt, J.W.; Griswold, J.P.

2011-01-01

Debris flows typically occur when intense rainfall or snowmelt triggers landslides or extensive erosion on steep, debris-mantled slopes. The flows can then grow dramatically in size and speed as they entrain material from their beds and banks, but the mechanism of this growth is unclear. Indeed, momentum conservation implies that entrainment of static material should retard the motion of the flows if friction remains unchanged. Here we use data from large-scale experiments to assess the entrainment of bed material by debris flows. We find that entrainment is accompanied by increased flow momentum and speed only if large positive pore pressures develop in wet bed sediments as the sediments are overridden by debris flows. The increased pore pressure facilitates progressive scour of the bed, reduces basal friction and instigates positive feedback that causes flow speed, mass and momentum to increase. If dryer bed sediment is entrained, however, the feedback becomes negative and flow momentum declines. We infer that analogous feedbacks could operate in other types of gravity-driven mass flow that interact with erodible beds. ?? 2011 Macmillan Publishers Limited. All rights reserved.

Post-irradiation hardness development, chemical softening, and thermal stability of bulk-fill and conventional resin-composites.

PubMed

Alshali, Ruwaida Z; Salim, Nesreen A; Satterthwaite, Julian D; Silikas, Nick

2015-02-01

To measure bottom/top hardness ratio of bulk-fill and conventional resin-composite materials, and to assess hardness changes after dry and ethanol storage. Filler content and kinetics of thermal decomposition were also tested using thermogravimetric analysis (TGA). Six bulk-fill (SureFil SDR, Venus bulk fill, X-tra base, Filtek bulk fill flowable, Sonic fill, and Tetric EvoCeram bulk-fill) and eight conventional resin-composite materials (Grandioso flow, Venus Diamond flow, X-flow, Filtek Supreme Ultra Flowable, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested (n=5). Initial and 24h (post-cure dry storage) top and bottom microhardness values were measured. Microhardness was re-measured after the samples were stored in 75% ethanol/water solution. Thermal decomposition and filler content were assessed by TGA. Results were analysed using one-way ANOVA and paired sample t-test (α=0.05). All materials showed significant increase of microhardness after 24h of dry storage which ranged from 100.1% to 9.1%. Bottom/top microhardness ratio >0.9 was exhibited by all materials. All materials showed significant decrease of microhardness after 24h of storage in 75% ethanol/water which ranged from 14.5% to 74.2%. The extent of post-irradiation hardness development was positively correlated to the extent of ethanol softening (R(2)=0.89, p<0.001). Initial thermal decomposition temperature assessed by TGA was variable and was correlated to ethanol softening. Bulk-fill resin-composites exhibit comparable bottom/top hardness ratio to conventional materials at recommended manufacturer thickness. Hardness was affected to a variable extent by storage with variable inorganic filler content and initial thermal decomposition shown by TGA. The manufacturer recommended depth of cure of bulk-fill resin-composites can be reached based on the microhardness method. Characterization of the primary polymer network of a resin-composite material should be considered when evaluating its stability in the aqueous oral environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modeling and analyzing flow of third grade nanofluid due to rotating stretchable disk with chemical reaction and heat source

NASA Astrophysics Data System (ADS)

Hayat, T.; Ahmad, Salman; Khan, M. Ijaz; Alsaedi, A.

2018-05-01

This article addresses flow of third grade nanofluid due to stretchable rotating disk. Mass and heat transports are analyzed through thermophoresis and Brownian movement effects. Further the effects of heat generation and chemical reaction are also accounted. The obtained ODE's are tackled computationally by means of homotopy analysis method. Graphical outcomes are analyzed for the effects of different variables. The obtained results show that velocity reduces through Reynolds number and material parameters. Temperature and concentration increase with Brownian motion and these decrease by Reynolds number.

Non-isothermal crystallization of poly(etheretherketone) aromatic polymer composite

NASA Technical Reports Server (NTRS)

Cebe, Peggy

1988-01-01

The nonisothermal crystallization kinetics of PEEK APC-2 and of 450G neat resin PEEK material were compared using a differential scanning calorimeter to monitor heat flow during crystallization; the effects of cooling rate on the crystallization temperature, the degree of crystallinity, and the conversion rate were investigated. A modified Avrami (1940) analysis was used to describe nonisothermal crystallization kinetics. It was found that, compared with the 450G neat resin PEEK, the nonisothermal crystallization of the PEEK APC-2 composite is characterized by higher initiation temperature, higher heat flow maximum temperature, and greater relative conversion by primary processes.

Low gas flow inductively coupled plasma optical emission spectrometry for the analysis of food samples after microwave digestion.

PubMed

Nowak, Sascha; Gesell, Monika; Holtkamp, Michael; Scheffer, Andy; Sperling, Michael; Karst, Uwe; Buscher, Wolfgang

2014-11-01

In this work, the recently introduced low flow inductively coupled plasma optical emission spectrometry (ICP-OES) with a total argon consumption below 0.7 L/min is applied for the first time to the field of food analysis. One goal is the investigation of the performance of this low flow plasma compared to a conventional ICP-OES system when non-aqueous samples with a certain matrix are introduced into the system. For this purpose, arsenic is determined in three different kinds of fish samples. In addition several nutrients (K, Na, Mg, Ca) and trace metals (Co, Cu, Mn, Cd, Pb, Zn, Fe, and Ni) are determined in honey samples (acacia) after microwave digestion. The precision of the measurements is characterized by relative standard deviations (RSD) and compared to the corresponding precision values achieved using the conventional Fassel-type torch of the ICP. To prove the accuracy of the low flow ICP-OES method, the obtained data from honey samples are validated by a conventional ICP-OES. For the measurements concerning arsenic in fish, the low flow ICP-OES values are validated by conventional Fassel-type ICP-OES. Furthermore, a certified reference material was investigated with the low gas flow setup. Limits of detection (LOD), according to the 3σ criterion, were determined to be in the low microgram per liter range for all analytes. Recovery rates in the range of 96-106% were observed for the determined trace metal elements. It was proven that the low gas flow ICP-OES leads to results that are comparable with those obtained with the Fassel-type torch for the analysis of food samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Bed-material entrainment and associated transportation infrastructure problems in streams of the Edwards Plateau, central Texas

USGS Publications Warehouse

Heitmuller, Franklin T.; Asquith, William H.

2008-01-01

The Texas Department of Transportation commonly builds and maintains low-water crossings (LWCs) over streams in the Edwards Plateau in Central Texas. LWCs are low-height structures, typically constructed of concrete and asphalt, that provide acceptable passage over seasonal rivers or streams with relatively low normal-depth flow. They are designed to accommodate flow by roadway overtopping during high-flow events. The streams of the Edwards Plateau are characterized by cobble- and gravel-sized bed material and highly variable flow regimes. Low base flows that occur most of the time occasionally are interrupted by severe floods. The floods entrain and transport substantial loads of bed material in the stream channels. As a result, LWCs over streams in the Edwards Plateau are bombarded and abraded by bed material during floods and periodically must be maintained or even replaced.

High energy density redox flow device

DOEpatents

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

2014-05-13

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

Temperature-dependent liquid metal flowrate control device

DOEpatents

Carlson, Roger D.

1978-01-01

A temperature-dependent liquid metal flowrate control device includes a magnet and a ferromagnetic member defining therebetween a flow path for liquid metal, the ferromagnetic member being formed of a material having a curie temperature at which a change in the flow rate of the liquid metal is desired. According to the preferred embodiment the magnet is a cylindrical rod magnet axially disposed within a cylindrical member formed of a curie material and having iron pole pieces at the ends. A cylindrical iron shunt and a thin wall stainless steel barrier are disposed in the annulus between magnet and curie material. Below the curie temperature flow between steel barrier and curie material is impeded and above the curie temperature flow impedance is reduced.

Direct and reverse pollen-mediated gene flow between GM rice and red rice weed

PubMed Central

Serrat, X.; Esteban, R.; Peñas, G.; Català, M. M.; Melé, E.; Messeguer, J.

2013-01-01

Potential risks of genetically modified (GM) crops must be identified before their commercialization, as happens with all new technologies. One of the major concerns is the proper risk assessment of adventitious presence of transgenic material in rice fields due to cross-pollination. Several studies have been conducted in order to quantify pollen-mediated gene flow from transgenic rice (Oryza sativa) to both conventional rice and red rice weed (O. sativa f. spontanea) under field conditions. Some of these studies reported GM pollen-donor rice transferring GM traits to red rice. However, gene flow also occurs in the opposite direction, in a phenomenon that we have called reverse gene flow, resulting in transgenic seeds that have incorporated the traits of wild red rice. We quantified reverse gene flow using material from two field trials. A molecular analysis based on amplified fragment length polymorphisms was carried out, being complemented with a phenotypic identification of red rice traits. In both field trials, the reverse gene flow detected was greater than the direct gene flow. The rate of direct gene flow varied according to the relative proportions of the donor (GM rice) and receptor (red rice) plants and was influenced by wind direction. The ecological impact of reverse gene flow is limited in comparison with that of direct gene flow because non-shattered and non-dormant seeds would be obtained in the first generation. Hybrid seed would remain in the spike and therefore most of it would be removed during harvesting. Nevertheless, this phenomenon must be considered in fields used for elite seed production and in developing countries where farmers often keep some seed for planting the following year. In these cases, there is a higher risk of GM red rice weed infestation increasing from year to year and therefore a proper monitoring plan needs to be established.

A flow-cytometry-based method to simplify the analysis and quantification of protein association to chromatin in mammalian cells

PubMed Central

Forment, Josep V.; Jackson, Stephen P.

2016-01-01

Protein accumulation on chromatin has traditionally been studied using immunofluorescence microscopy or biochemical cellular fractionation followed by western immunoblot analysis. As a way to improve the reproducibility of this kind of analysis, make it easier to quantify and allow a stream-lined application in high-throughput screens, we recently combined a classical immunofluorescence microscopy detection technique with flow cytometry1. In addition to the features described above, and by combining it with detection of both DNA content and DNA replication, this method allows unequivocal and direct assignment of cell-cycle distribution of protein association to chromatin without the need for cell culture synchronization. Furthermore, it is relatively quick (no more than a working day from sample collection to quantification), requires less starting material compared to standard biochemical fractionation methods and overcomes the need for flat, adherent cell types that are required for immunofluorescence microscopy. PMID:26226461

Investigation of powder injection moulded oblique fin heat sinks

NASA Astrophysics Data System (ADS)

Sai, Vadri Siva

The present work attempts to study the fluid flow and heat transfer characteristics of PIM oblique finned microchannel heat sink both numerically and experimentally. Experimental results such as thermal resistance and pressure drop have been well validated with ANSYS FLUENT simulations. Hot spots are observed at the most downstream location of the channel is due to the effect of flow migration. Finally, a novel technique has been proposed to reduce the pressure drop on creating additional channels by removing some material at the middle portion of oblique fins. It is found that the creation of oblique cuts incurred a reduction in both pressure drop and Nuavg up to 31.36 % and 16.66 % respectively at a flow rate of 500 ml/min. Nevertheless, for all the flowrates considered in this analysis. % reduction in pressure drop is almost double as compared with % reduction in Nuavg. Therefore, this analysis is beneflcial in reducing the additional cost incurs due to pressure drop penalty.

Sheet metal stamping die design for warm forming

DOEpatents

Ghosh, Amit K.

2003-04-22

In metal stamping dies, by taking advantage of improved material flow by selectively warming the die, flat sections of the die can contribute to the flow of material throughout the workpiece. Local surface heating can be accomplished by placing a heating block in the die. Distribution of heating at the flat lower train central regions outside of the bend region allows a softer flow at a lower stress to enable material flow into the thinner, higher strain areas at the bend/s. The heating block is inserted into the die and is powered by a power supply.

Scoping Study of Machine Learning Techniques for Visualization and Analysis of Multi-source Data in Nuclear Safeguards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Yonggang

In implementation of nuclear safeguards, many different techniques are being used to monitor operation of nuclear facilities and safeguard nuclear materials, ranging from radiation detectors, flow monitors, video surveillance, satellite imagers, digital seals to open source search and reports of onsite inspections/verifications. Each technique measures one or more unique properties related to nuclear materials or operation processes. Because these data sets have no or loose correlations, it could be beneficial to analyze the data sets together to improve the effectiveness and efficiency of safeguards processes. Advanced visualization techniques and machine-learning based multi-modality analysis could be effective tools in such integratedmore » analysis. In this project, we will conduct a survey of existing visualization and analysis techniques for multi-source data and assess their potential values in nuclear safeguards.« less

Colin A. McMillan | NREL

Science.gov Websites

Colin A. McMillan Photo of Colin A. McMillan. Colin McMillan Researcher IV-Operations Research Econometrics Research Interests Systems-level energy efficiency analysis Material and energy flows in economies ; Journal of Industrial Ecology 17, no. 5 (October 2013): 700-11. doi:10.1111/jiec.12050 McMillan, C.A., S.J

Premium quality 5A1-2.5 Sn ELI titanium production

NASA Technical Reports Server (NTRS)

Dessau, P. P.; Harris, C. L.

1972-01-01

Preliminary design and reliability analysis conducted on the turbopump for the NERVA 75,000 full flow cycle engine, indicated that the turbopump bearings were the most critical turbopump parts in meeting the 10 hour life at the required turbopump reliability of .99978. The analysis revealed that significant reductions (approximately a factor of 3.25) in bearing loads would be achieved by fabricating the rotating parts from titanium in lieu of A286 or 718. This is basically due to the difference in density of the materials and the resulting mass effect on the location of the first and second stick mode critical speeds. For the selected rotor configuration, the lighter material has a first critical speed at approximately 36,000 rpm, while that of the heavier material has a first critical at approximately 27,000 rpm. As the operating range of the turbopump is from 0 to 30,000 rpm, the heavier material would have a stick mode critical in the operating range.

Statistical Analysis of an Infrared Thermography Inspection of Reinforced Carbon-Carbon

NASA Technical Reports Server (NTRS)

Comeaux, Kayla

2011-01-01

Each piece of flight hardware being used on the shuttle must be analyzed and pass NASA requirements before the shuttle is ready for launch. One tool used to detect cracks that lie within flight hardware is Infrared Flash Thermography. This is a non-destructive testing technique which uses an intense flash of light to heat up the surface of a material after which an Infrared camera is used to record the cooling of the material. Since cracks within the material obstruct the natural heat flow through the material, they are visible when viewing the data from the Infrared camera. We used Ecotherm, a software program, to collect data pertaining to the delaminations and analyzed the data using Ecotherm and University of Dayton Log Logistic Probability of Detection (POD) Software. The goal was to reproduce the statistical analysis produced by the University of Dayton software, by using scatter plots, log transforms, and residuals to test the assumption of normality for the residuals.

Wildfire-related debris-flow initiation processes, Storm King Mountain, Colorado

USGS Publications Warehouse

Cannon, S.H.; Kirkham, R.M.; Parise, M.

2001-01-01

A torrential rainstorm on September 1, 1994 at the recently burned hillslopes of Storm King Mountain, CO, resulted in the generation of debris flows from every burned drainage basin. Maps (1:5000 scale) of bedrock and surficial materials and of the debris-flow paths, coupled with a 10-m Digital Elevation Model (DEM) of topography, are used to evaluate the processes that generated fire-related debris flows in this setting. These evaluations form the basis for a descriptive model for fire-related debris-flow initiation. The prominent paths left by the debris flows originated in 0- and 1st-order hollows or channels. Discrete soil-slip scars do not occur at the heads of these paths. Although 58 soil-slip scars were mapped on hillslopes in the burned basins, material derived from these soil slips accounted for only about 7% of the total volume of material deposited at canyon mouths. This fact, combined with observations of significant erosion of hillslope materials, suggests that a runoff-dominated process of progressive sediment entrainment by surface runoff, rather than infiltration-triggered failure of discrete soil slips, was the primary mechanism of debris-flow initiation. A paucity of channel incision, along with observations of extensive hillslope erosion, indicates that a significant proportion of material in the debris flows was derived from the hillslopes, with a smaller contribution from the channels. Because of the importance of runoff-dominated rather than infiltration-dominated processes in the generation of these fire-related debris flows, the runoff-contributing area that extends upslope from the point of debris-flow initiation to the drainage divide, and its gradient, becomes a critical constraint in debris-flow initiation. Slope-area thresholds for fire-related debris-flow initiation from Storm King Mountain are defined by functions of the form Acr(tan ??)3 = S, where Acr is the critical area extending upslope from the initiation location to the drainage divide, and tan ?? is its gradient. The thresholds vary with different materials. ?? 2001 Elsevier Science B.V. All rights reserved.

Flow-Tube Reactor Experiments on the High Temperature Oxidation of Carbon Weaves

NASA Technical Reports Server (NTRS)

Panerai, Francesco; White, Jason D.; Robertson, Robert; Borner, Arnaud; Ferguson, Joseph C.; Mansour, Nagi N.

2017-01-01

Under entry conditions carbon weaves used in thermal protection systems (TPS) decompose via oxidation. Modeling this phenomenon is challenging due to the different regimes encountered along a flight trajectory. Approaches using equilibrium chemistry may lead to over-estimated mass loss and recession at certain conditions. Concurrently, there is a shortcoming of experimental data on carbon weaves to enable development of improved models. In this work, a flow-tube test facility was used to measure the oxidation of carbon weaves at temperatures up to 1500 K. The material tested was the 3D carbon weave used for the heat shield of the NASA Adaptive Deployable Entry and Placement Technology, ADEPT. Oxidation was characterized by quantifying decomposition gases (CO and CO2), by mass measurements, and by microscale surface analysis. The current set of measurements contributes to the development of finite rate chemistry models for carbon fabrics used in woven TPS materials.

NASA Lewis Steady-State Heat Pipe Code Architecture

NASA Technical Reports Server (NTRS)

Mi, Ye; Tower, Leonard K.

2013-01-01

NASA Glenn Research Center (GRC) has developed the LERCHP code. The PC-based LERCHP code can be used to predict the steady-state performance of heat pipes, including the determination of operating temperature and operating limits which might be encountered under specified conditions. The code contains a vapor flow algorithm which incorporates vapor compressibility and axially varying heat input. For the liquid flow in the wick, Darcy s formula is employed. Thermal boundary conditions and geometric structures can be defined through an interactive input interface. A variety of fluid and material options as well as user defined options can be chosen for the working fluid, wick, and pipe materials. This report documents the current effort at GRC to update the LERCHP code for operating in a Microsoft Windows (Microsoft Corporation) environment. A detailed analysis of the model is presented. The programming architecture for the numerical calculations is explained and flowcharts of the key subroutines are given

A Finite Element Study of Micropipette Aspiration of Single Cells: Effect of Compressibility

PubMed Central

Jafari Bidhendi, Amirhossein; Korhonen, Rami K.

2012-01-01

Micropipette aspiration (MA) technique has been widely used to measure the viscoelastic properties of different cell types. Cells experience nonlinear large deformations during the aspiration procedure. Neo-Hookean viscohyperelastic (NHVH) incompressible and compressible models were used to simulate the creep behavior of cells in MA, particularly accounting for the effect of compressibility, bulk relaxation, and hardening phenomena under large strain. In order to find optimal material parameters, the models were fitted to the experimental data available for mesenchymal stem cells. Finally, through Neo-Hookean porohyperelastic (NHPH) material model for the cell, the influence of fluid flow on the aspiration length of the cell was studied. Based on the results, we suggest that the compressibility and bulk relaxation/fluid flow play a significant role in the deformation behavior of single cells and should be taken into account in the analysis of the mechanics of cells. PMID:22400045

Turbulent motion of mass flows. Mathematical modeling

NASA Astrophysics Data System (ADS)

Eglit, Margarita; Yakubenko, Alexander; Yakubenko, Tatiana

2016-04-01

New mathematical models for unsteady turbulent mass flows, e.g., dense snow avalanches and landslides, are presented. Such models are important since most of large scale flows are turbulent. In addition to turbulence, the two other important points are taken into account: the entrainment of the underlying material by the flow and the nonlinear rheology of moving material. The majority of existing models are based on the depth-averaged equations and the turbulent character of the flow is accounted by inclusion of drag proportional to the velocity squared. In this paper full (not depth-averaged) equations are used. It is assumed that basal entrainment takes place if the bed friction equals the shear strength of the underlying layer (Issler D, M. Pastor Peréz. 2011). The turbulent characteristics of the flow are calculated using a three-parameter differential model (Lushchik et al., 1978). The rheological properties of moving material are modeled by one of the three types of equations: 1) Newtonian fluid with high viscosity, 2) power-law fluid and 3) Bingham fluid. Unsteady turbulent flows down long homogeneous slope are considered. The flow dynamical parameters and entrainment rate behavior in time as well as their dependence on properties of moving and underlying materials are studied numerically. REFERENCES M.E. Eglit and A.E. Yakubenko, 2014. Numerical modeling of slope flows entraining bottom material. Cold Reg. Sci. Technol., 108, 139-148 Margarita E. Eglit and Alexander E. Yakubenko, 2016. The effect of bed material entrainment and non-Newtonian rheology on dynamics of turbulent slope flows. Fluid Dynamics, 51(3) Issler D, M. Pastor Peréz. 2011. Interplay of entrainment and rheology in snow avalanches; a numerical study. Annals of Glaciology, 52(58), 143-147 Lushchik, V.G., Paveliev, A.A. , and Yakubenko, A.E., 1978. Three-parameter model of shear turbulence. Fluid Dynamics, 13, (3), 350-362

40 CFR 63.605 - Monitoring requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the mass flow of phosphorus-bearing feed material to the process. The monitoring system shall have an... either the mass flow of phosphorus-bearing feed material to the dryer or calciner, or the mass flow of... total mass rate in metric ton/hour of phosphorus bearing feed using a monitoring system for measuring...

40 CFR 63.605 - Monitoring requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the mass flow of phosphorus-bearing feed material to the process. The monitoring system shall have an... either the mass flow of phosphorus-bearing feed material to the dryer or calciner, or the mass flow of... total mass rate in metric ton/hour of phosphorus bearing feed using a monitoring system for measuring...

Flow speed of the ablation vapors generated during laser drilling of CFRP with a continuous-wave laser beam

NASA Astrophysics Data System (ADS)

Faas, S.; Freitag, C.; Boley, S.; Berger, P.; Weber, R.; Graf, T.

2017-03-01

The hot plume of ablation products generated during the laser drilling process of carbon fiber reinforced plastics (CFRP) with a continuous-wave laser beam was analyzed by means of high-speed imaging. The formation of compression shocks was observed within the flow of the evaporated material, which is an indication of flow speeds well above the local speed of sound. The flow speed of the hot ablation products can be estimated by analyzing the position of these compression shocks. We investigated the temporal evolution of the flow speed during the drilling process and the influence of the average laser power on the flow speed. The flow speed increases with increasing average laser powers. The moment of drilling through the material changes the conditions for the drilling process and was confirmed to influence the flow speed of the ablated material. Compression shocks can also be observed during laser cutting of CFRP with a moving laser beam.

Flow behavior and mobility of contaminated waste rock materials in the abandoned Imgi mine in Korea

NASA Astrophysics Data System (ADS)

Jeong, S. W.; Wu, Y.-H.; Cho, Y. C.; Ji, S. W.

2018-01-01

Incomplete mine reclamation can cause ecological and environmental impacts. This paper focuses on the geotechnical and rheological characteristics of waste rock materials, which are mainly composed of sand-size particles, potentially resulting in mass movement (e.g., slide or flow) and extensive acid mine drainage. To examine the potential for contaminant mobilization resulting from physicochemical processes in abandoned mines, a series of scenario-based debris flow simulations was conducted using Debris-2D to identify different hazard scenarios and volumes. The flow behavior of waste rock materials was examined using a ball-measuring rheometric apparatus, which can be adapted for large particle samples, such as debris flow. Bingham yield stresses determined in controlled shear rate mode were used as an input parameter in the debris flow modeling. The yield stresses ranged from 100 to 1000 Pa for shear rates ranging from 10- 5 to 102 s- 1. The results demonstrated that the lowest yield stress could result in high mobility of debris flow (e.g., runout distance > 700 m from the source area for 60 s); consequently, the material contaminants may easily reach the confluence of the Suyoung River through a mountain stream. When a fast slide or debris flow occurs at or near an abandoned mine area, it may result in extremely dynamic and destructive geomorphological changes. Even for the highest yield stress of debris flow simulation (i.e., τy = 2000 Pa), the released debris could flow into the mountain stream; therefore, people living near abandoned mines may become exposed to water pollution throughout the day. To maintain safety at and near abandoned mines, the physicochemical properties of waste materials should be monitored, and proper mitigation measures post-mining should be considered in terms of both their physical damage and chemical pollution potential.

Effect of analysis parameters on non-linear implicit finite element analysis of marine corroded steel plate

NASA Astrophysics Data System (ADS)

Islam, Muhammad Rabiul; Sakib-Ul-Alam, Md.; Nazat, Kazi Kaarima; Hassan, M. Munir

2017-12-01

FEA results greatly depend on analysis parameters. MSC NASTRAN nonlinear implicit analysis code has been used in large deformation finite element analysis of pitted marine SM490A steel rectangular plate. The effect of two types actual pit shape on parameters of integrity of structure has been analyzed. For 3-D modeling, a proposed method for simulation of pitted surface by probabilistic corrosion model has been used. The result has been verified with the empirical formula proposed by finite element analysis of steel surface generated with different pitted data where analyses have been carried out by the code of LS-DYNA 971. In the both solver, an elasto-plastic material has been used where an arbitrary stress versus strain curve can be defined. In the later one, the material model is based on the J2 flow theory with isotropic hardening where a radial return algorithm is used. The comparison shows good agreement between the two results which ensures successful simulation with comparatively less energy and time.

A geomorphic explanation for a meander cutoff following channel relocation of a coarse-bedded river.

PubMed

Thompson, Douglas M

2003-03-01

The Veteran's Fishing section of the Blackledge River in central Connecticut was relocated in the late 1950s. The relocation resulted in an unstable channel despite extensive efforts to prevent erosion. Overbank erosion and meander cutoffs were investigated using detailed survey data, characterizations of sediment deposits, flow modeling, and a moment-stability analysis. Limited reworking of revetment boulders indicate that riprap bank material was immobile during a 1979 flood event responsible for the formation of the cutoff channel. A moment-stability analysis factor-of-safety value of 1.1 supports the conclusion that riprap was not directly eroded from the banks. Alluvial particles with d(95) values ranging up to 120 mm were deposited along a bar downstream from the cutoff channel at flows estimated to be below a 1.5-year recurrence interval flow. Development of the bar deposit resulted in locally elevated water surfaces at high flow. The resulting overbank flow across the meander neck to the adjacent downstream bend led to the creation of an upstream migrating knickpoint, the erosion of approximately 16,000-year-old sediments, and the subsequent meander cutoff. The results of the study indicate that traditional erosion-control measures cannot prevent extreme channel adjustments if the geomorphic processes that control sediment continuity also are not considered.

Enzymatic amplification of a flow-injected thermometric enzyme-linked immunoassay for human insulin.

PubMed

Mecklenburg, M; Lindbladh, C; Li, H; Mosbach, K; Danielsson, B

1993-08-01

A flow-injected thermometric enzyme linked immunoassay for human insulin which employs the lactate dehydrogenase/lactate oxidase (LDH/LOD) substrate recycling system for signal amplification is described. The system is composed of two columns, an immunosorbent column containing immobilized anti-insulin antibodies for sensing and a recycling column containing immobilized LDH/LOD/Catalase for detection. The effect of flow rates, conjugate concentrations, and chromatographic support material upon the sensitivity of the assay are investigated. The assay has a detection limit of 0.025 microgram/ml and a linear range from 0.05 to 2 micrograms/ml. This corresponds to a 10-fold increase in sensitivity over the unamplified system. A recombinant human insulin-proinsulin conjugate was also tested. The results show that enzymatic amplification can be employed to increase the sensitivity and reproducibility of flow injection assay-based biosensors. The implications of these results upon on-line analysis are discussed.

Self-organization in suspensions of end-functionalized semiflexible polymers under shear flow

NASA Astrophysics Data System (ADS)

Myung, Jin Suk; Winkler, Roland G.; Gompper, Gerhard

2015-12-01

The nonequilibrium dynamical behavior and structure formation of end-functionalized semiflexible polymer suspensions under flow are investigated by mesoscale hydrodynamic simulations. The hybrid simulation approach combines the multiparticle collision dynamics method for the fluid, which accounts for hydrodynamic interactions, with molecular dynamics simulations for the semiflexible polymers. In equilibrium, various kinds of scaffold-like network structures are observed, depending on polymer flexibility and end-attraction strength. We investigate the flow behavior of the polymer networks under shear and analyze their nonequilibrium structural and rheological properties. The scaffold structure breaks up and densified aggregates are formed at low shear rates, while the structural integrity is completely lost at high shear rates. We provide a detailed analysis of the shear- rate-dependent flow-induced structures. The studies provide a deeper understanding of the formation and deformation of network structures in complex materials.

Magnetic Control in Crystal Growth from a Melt

NASA Astrophysics Data System (ADS)

Huang, Yue

Control of bulk melt crystal growth techniques is desirable for producing semiconductors with the highest purity and ternary alloys with tunable electrical properties. Because these molten materials are electrically conducting, external magnetic fields are often employed to regulate the flow in the melt. However, complicated by the coupled flow, thermal, electromagnetic and chemical physics, such magnetic control is typically empirical or even an educated guess. Two magnetic flow control mechanisms: flow damping by steady magnetic fields, and flow stirring by alternating magnetic fields, are investigated numerically. Magnetic damping during optically-heated float-zone crystal growth is modeled using a spectral collocation method. The Marangoni convection at the free melt-gas interface is suppressed when exposed to a steady axial magnetic field, measured by the Hartmann number Ha. As a result, detrimental flow instabilities are suppressed, and an almost quiescent region forms in the interior, ideal for single crystal growth. Using normal mode linear stability analyses, dominant flow instabilities are determined in a range applicable to experiments (up to Ha = 300 for Pr = 0.02, and up to Ha = 500 for Pr = 0.001). The hydrodynamic nature of the instability for small Prandtl number Pr liquid bridges is confirmed by energy analyses. Magnetic stirring is modeled for melt crystal growth in an ampule exposed to a transverse rotating magnetic field. Decoupled from the flow field at small magnetic Reynolds number, the electromagnetic field is first solved via finite element analysis. The flow field is then solved using the spectral element method. At low to moderate AC frequencies (up to a few kHz), the electromagnetic body force is dominant in the azimuthal direction, which stirs a steady axisymmetric flow primarily in the azimuthal direction. A weaker secondary flow develops in the meridional plane. However, at high AC frequencies (on the order of 10 kHz and higher), only the flow within a skin depth is directly stirred due to the magnetic shielding effect. By regulating the flow in the melt, magnetic control can improve grown-crystal properties in new materials, and achieve economically viable growth rates for production of novel crystalline semiconductors.

Microfluidic device and methods for focusing fluid streams using electroosmotically induced pressures

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael

2010-06-01

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either electric current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to electrokinetically inducing fluid flow to confine a selected material in a region of a microchannel that is not influenced by an electric field. Other structures for inducing fluid flow in accordance with this invention include nanochannel bridging membranes and alternating current fluid pumping devices. Applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Simulation Analysis of Fluid-Structure Interaction of High Velocity Environment Influence on Aircraft Wing Materials under Different Mach Numbers.

PubMed

Zhang, Lijun; Sun, Changyan

2018-04-18

Aircraft service process is in a state of the composite load of pressure and temperature for a long period of time, which inevitably affects the inherent characteristics of some components in aircraft accordingly. The flow field of aircraft wing materials under different Mach numbers is simulated by Fluent in order to extract pressure and temperature on the wing in this paper. To determine the effect of coupling stress on the wing’s material and structural properties, the fluid-structure interaction (FSI) method is used in ANSYS-Workbench to calculate the stress that is caused by pressure and temperature. Simulation analysis results show that with the increase of Mach number, the pressure and temperature on the wing’s surface both increase exponentially and thermal stress that is caused by temperature will be the main factor in the coupled stress. When compared with three kinds of materials, titanium alloy, aluminum alloy, and Haynes alloy, carbon fiber composite material has better performance in service at high speed, and natural frequency under coupling pre-stressing will get smaller.

Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

NASA Astrophysics Data System (ADS)

Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

2017-05-01

Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

Simulation Analysis of Fluid-Structure Interaction of High Velocity Environment Influence on Aircraft Wing Materials under Different Mach Numbers

PubMed Central

Sun, Changyan

2018-01-01

Aircraft service process is in a state of the composite load of pressure and temperature for a long period of time, which inevitably affects the inherent characteristics of some components in aircraft accordingly. The flow field of aircraft wing materials under different Mach numbers is simulated by Fluent in order to extract pressure and temperature on the wing in this paper. To determine the effect of coupling stress on the wing’s material and structural properties, the fluid-structure interaction (FSI) method is used in ANSYS-Workbench to calculate the stress that is caused by pressure and temperature. Simulation analysis results show that with the increase of Mach number, the pressure and temperature on the wing’s surface both increase exponentially and thermal stress that is caused by temperature will be the main factor in the coupled stress. When compared with three kinds of materials, titanium alloy, aluminum alloy, and Haynes alloy, carbon fiber composite material has better performance in service at high speed, and natural frequency under coupling pre-stressing will get smaller. PMID:29670023

Wash load and bed-material load transport in the Yellow River

USGS Publications Warehouse

Yang, C.T.; Simoes, F.J.M.

2005-01-01

It has been the conventional assumption that wash load is supply limited and is only indirectly related to the hydraulics of a river. Hydraulic engineers also assumed that bed-material load concentration is independent of wash load concentration. This paper provides a detailed analysis of the Yellow River sediment transport data to determine whether the above assumptions are true and whether wash load concentration can be computed from the original unit stream power formula and the modified unit stream power formula for sediment-laden flows. A systematic and thorough analysis of 1,160 sets of data collected from 9 gauging stations along the Middle and Lower Yellow River confirmed that the method suggested by the conjunctive use of the two formulas can be used to compute wash load, bed-material load, and total load in the Yellow River with accuracy. Journal of Hydraulic Engineering ?? ASCE.

Experimental investigation of gas flow rate and electric field effect on refractive index and electron density distribution of cold atmospheric pressure-plasma by optical method, Moiré deflectometry

NASA Astrophysics Data System (ADS)

Khanzadeh, Mohammad; Jamal, Fatemeh; Shariat, Mahdi

2018-04-01

Nowadays, cold atmospheric-pressure (CAP) helium plasma jets are widely used in material processing devices in various industries. Researchers often use indirect and spectrometric methods for measuring the plasma parameters which are very expensive. In this paper, for the first time, characterization of CAP, i.e., finding its parameters such as refractive index and electron density distribution, was carried out using an optical method, Moiré deflectometry. This method is a wave front analysis technique based on geometric optics. The advantages of this method are simplicity, high accuracy, and low cost along with the non-contact, non-destructive, and direct measurement of CAP parameters. This method demonstrates that as the helium gas flow rate decreases, the refractive index increases. Also, we must note that the refractive index is larger in the gas flow consisting of different flow rates of plasma comparing with the gas flow without the plasma.

Preliminary analysis of phosphorus flow in Hue Citadel.

PubMed

Anh, T N Q; Harada, H; Fujii, S; Anh, P N; Lieu, P K; Tanaka, S

2016-01-01

Characteristics of waste and wastewater management can affect material flows. Our research investigates the management of waste and wastewater in urban areas of developing countries and its effects on phosphorus flow based on a case study in Hue Citadel, Hue, Vietnam. One hundred households were interviewed to gain insight into domestic waste and wastewater management together with secondary data collection. Next, a phosphorus flow model was developed to quantify the phosphorus input and output in the area. The results showed that almost all wastewater generated in Hue Citadel was eventually discharged into water bodies and to the ground/groundwater. This led to most of the phosphorus output flowing into water bodies (41.2 kg P/(ha year)) and ground/groundwater (25.3 kg P/(ha year)). Sewage from the sewer system was the largest source of phosphorus loading into water bodies, while effluent from on-site sanitation systems was responsible for a major portion of phosphorus into the ground/groundwater. This elevated phosphorus loading is a serious issue in considering surface water and groundwater protection.

High-Strain-Rate Material Behavior and Adiabatic Material Instability in Impact of Micron-Scale Al-6061 Particles

NASA Astrophysics Data System (ADS)

Chen, Qiyong; Alizadeh, Arash; Xie, Wanting; Wang, Xuemei; Champagne, Victor; Gouldstone, Andrew; Lee, Jae-Hwang; Müftü, Sinan

2018-04-01

Impact of spherical particles onto a flat sapphire surface was investigated in 50-950 m/s impact speed range experimentally and theoretically. Material parameters of the bilinear Johnson-Cook model were determined based on comparison of deformed particle shapes from experiment and simulation. Effects of high-strain-rate plastic flow, heat generation due to plasticity, material damage, interfacial friction and heat transfer were modeled. Four distinct regions were identified inside the particle by analyzing temporal variation of material flow. A relatively small volume of material near the impact zone becomes unstable due to plasticity-induced heating, accompanied by severe drop in the flow stress for impact velocity that exceeds 500 m/s. Outside of this region, flow stress is reduced due to temperature effects without the instability. Load carrying capacity of the material degrades and the material expands horizontally leading to jetting. The increase in overall plastic and frictional dissipation with impact velocity was found to be inherently lower than the increase in the kinetic energy at high speeds, leading to the instability. This work introduces a novel method to characterize HSR (109 s-1) material properties and also explains coupling between HSR material behavior and mechanics that lead to extreme deformation.

Nonlocal rheological properties of granular flows near a jamming limit.

PubMed

Aranson, Igor S; Tsimring, Lev S; Malloggi, Florent; Clément, Eric

2008-09-01

We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology. The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.

Non-local rheological properties of granular flows near a jamming limit.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aranson, I. S.; Tsimring, L. S.; Malloggi, F.

2008-01-01

We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology.more » The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.« less

Method and apparatus for in-cell vacuuming of radiologically contaminated materials

DOEpatents

Spadaro, Peter R.; Smith, Jay E.; Speer, Elmer L.; Cecconi, Arnold L.

1987-01-01

A vacuum air flow operated cyclone separator arrangement for collecting, handling and packaging loose contaminated material in accordance with acceptable radiological and criticality control requirements. The vacuum air flow system includes a specially designed fail-safe prefilter installed upstream of the vacuum air flow power supply. The fail-safe prefilter provides in-cell vacuum system flow visualization and automatically reduces or shuts off the vacuum air flow in the event of an upstream prefilter failure. The system is effective for collecting and handling highly contaminated radiological waste in the form of dust, dirt, fuel element fines, metal chips and similar loose material in accordance with radiological and criticality control requirements for disposal by means of shipment and burial.

Transient shear banding in the nematic dumbbell model of liquid crystalline polymers

NASA Astrophysics Data System (ADS)

Adams, J. M.; Corbett, D.

2018-05-01

In the shear flow of liquid crystalline polymers (LCPs) the nematic director orientation can align with the flow direction for some materials but continuously tumble in others. The nematic dumbbell (ND) model was originally developed to describe the rheology of flow-aligning semiflexible LCPs, and flow-aligning LCPs are the focus in this paper. In the shear flow of monodomain LCPs, it is usually assumed that the spatial distribution of the velocity is uniform. This is in contrast to polymer solutions, where highly nonuniform spatial velocity profiles have been observed in experiments. We analyze the ND model, with an additional gradient term in the constitutive model, using a linear stability analysis. We investigate the separate cases of constant applied shear stress and constant applied shear rate. We find that the ND model has a transient flow instability to the formation of a spatially inhomogeneous flow velocity for certain starting orientations of the director. We calculate the spatially resolved flow profile in both constant applied stress and constant applied shear rate in start up from rest, using a model with one spatial dimension to illustrate the flow behavior of the fluid. For low shear rates flow reversal can be seen as the director realigns with the flow direction, whereas for high shear rates the director reorientation occurs simultaneously across the gap. Experimentally, this inhomogeneous flow is predicted to be observed in flow reversal experiments in LCPs.

An overview of active flow control actuators and applications (presentation video)

NASA Astrophysics Data System (ADS)

Brzozowski, Daniel; Whalen, Edward A.

2014-04-01

Active Flow Control (AFC) is an emerging technology which promises performance enhancements to both military and civilian aircraft. A technique which uses energy input at discrete locations to manipulate the flow over an aerodynamic surface, AFC may be used to reduce drag, prevent flow separation, and enable otherwise-infeasible aerodynamic designs. Additional applications include shear layer and turbulence control for aero-optics applications and mixing enhancement for thermal applications. Many AFC applications call for a high frequency fluidic perturbation provided by an electrically-powered actuator. In these instances, piezoelectric (PZT) materials have served as the workhorse for flow control actuators, such as the widely-studied synthetic jet. Because the PZT materials form the critical component of the actuator, the maximum performance of the synthetic jet (velocity and momentum output) is limited by the physical limitations of the PZT material. The purpose of this presentation is to provide a high level overview of AFC actuators and applications in an attempt to engage the smart materials community and encourage advanced material development in support of these crucial applications.

[Ecological management model of agriculture-pasture ecotone based on the theory of energy and material flow--a case study in Houshan dryland area of Inner Mongolia].

PubMed

Fan, Jinlong; Pan, Zhihua; Zhao, Ju; Zheng, Dawei; Tuo, Debao; Zhao, Peiyi

2004-04-01

The degradation of ecological environment in the agriculture-pasture ecotone in northern China has been paid more attentions. Based on our many years' research and under the guide of energy and material flow theory, this paper put forward an ecological management model, with a hill as the basic cell and according to the natural, social and economic characters of Houshan dryland farming area inside the north agriculture-pasture ecotone. The input and output of three models, i.e., the traditional along-slope-tillage model, the artificial grassland model and the ecological management model, were observed and recorded in detail in 1999. Energy and material flow analysis based on field test showed that compared with traditional model, ecological management model could increase solar use efficiency by 8.3%, energy output by 8.7%, energy conversion efficiency by 19.4%, N output by 26.5%, N conversion efficiency by 57.1%, P output by 12.1%, P conversion efficiency by 45.0%, and water use efficiency by 17.7%. Among the models, artificial grassland model had the lowest solar use efficiency, energy output and energy conversion efficiency; while the ecological management model had the most outputs and benefits, was the best model with high economic effect, and increased economic benefits by 16.1%, compared with the traditional model.

A hydrodynamic model for granular material flows including segregation effects

NASA Astrophysics Data System (ADS)

Gilberg, Dominik; Klar, Axel; Steiner, Konrad

2017-06-01

The simulation of granular flows including segregation effects in large industrial processes using particle methods is accurate, but very time-consuming. To overcome the long computation times a macroscopic model is a natural choice. Therefore, we couple a mixture theory based segregation model to a hydrodynamic model of Navier-Stokes-type, describing the flow behavior of the granular material. The granular flow model is a hybrid model derived from kinetic theory and a soil mechanical approach to cover the regime of fast dilute flow, as well as slow dense flow, where the density of the granular material is close to the maximum packing density. Originally, the segregation model has been formulated by Thornton and Gray for idealized avalanches. It is modified and adapted to be in the preferred form for the coupling. In the final coupled model the segregation process depends on the local state of the granular system. On the other hand, the granular system changes as differently mixed regions of the granular material differ i.e. in the packing density. For the modeling process the focus lies on dry granular material flows of two particle types differing only in size but can be easily extended to arbitrary granular mixtures of different particle size and density. To solve the coupled system a finite volume approach is used. To test the model the rotational mixing of small and large particles in a tumbler is simulated.

Optimal concentrations in transport systems

PubMed Central

Jensen, Kaare H.; Kim, Wonjung; Holbrook, N. Michele; Bush, John W. M.

2013-01-01

Many biological and man-made systems rely on transport systems for the distribution of material, for example matter and energy. Material transfer in these systems is determined by the flow rate and the concentration of material. While the most concentrated solutions offer the greatest potential in terms of material transfer, impedance typically increases with concentration, thus making them the most difficult to transport. We develop a general framework for describing systems for which impedance increases with concentration, and consider material flow in four different natural systems: blood flow in vertebrates, sugar transport in vascular plants and two modes of nectar drinking in birds and insects. The model provides a simple method for determining the optimum concentration copt in these systems. The model further suggests that the impedance at the optimum concentration μopt may be expressed in terms of the impedance of the pure (c = 0) carrier medium μ0 as μopt∼2αμ0, where the power α is prescribed by the specific flow constraints, for example constant pressure for blood flow (α = 1) or constant work rate for certain nectar-drinking insects (α = 6). Comparing the model predictions with experimental data from more than 100 animal and plant species, we find that the simple model rationalizes the observed concentrations and impedances. The model provides a universal framework for studying flows impeded by concentration, and yields insight into optimization in engineered systems, such as traffic flow. PMID:23594815

LOX/LH2 vane pump for auxiliary propulsion systems

NASA Technical Reports Server (NTRS)

Hemminger, J. A.; Ulbricht, T. E.

1985-01-01

Positive displacement pumps offer potential efficiency advantages over centrifugal pumps for future low thrust space missions. Low flow rate applications, such as space station auxiliary propulsion or dedicated low thrust orbiter transfer vehicles, are typical of missions where low flow and high head rise challenge centrifugal pumps. The positive displacement vane pump for pumping of LOX and LH2 is investigated. This effort has included: (1) a testing program in which pump performance was investigated for differing pump clearances and for differing pump materials while pumping LN2, LOX, and LH2; and (2) an analysis effort, in which a comprehensive pump performance analysis computer code was developed and exercised. An overview of the theoretical framework of the performance analysis computer code is presented, along with a summary of analysis results. Experimental results are presented for pump operating in liquid nitrogen. Included are data on the effects on pump performance of pump clearance, speed, and pressure rise. Pump suction performance is also presented.

Steady-state hydrodynamic instabilities of active liquid crystals: hybrid lattice Boltzmann simulations.

PubMed

Marenduzzo, D; Orlandini, E; Cates, M E; Yeomans, J M

2007-09-01

We report hybrid lattice Boltzmann (HLB) simulations of the hydrodynamics of an active nematic liquid crystal sandwiched between confining walls with various anchoring conditions. We confirm the existence of a transition between a passive phase and an active phase, in which there is spontaneous flow in the steady state. This transition is attained for sufficiently "extensile" rods, in the case of flow-aligning liquid crystals, and for sufficiently "contractile" ones for flow-tumbling materials. In a quasi-one-dimensional geometry, deep in the active phase of flow-aligning materials, our simulations give evidence of hysteresis and history-dependent steady states, as well as of spontaneous banded flow. Flow-tumbling materials, in contrast, rearrange themselves so that only the two boundary layers flow in steady state. Two-dimensional simulations, with periodic boundary conditions, show additional instabilities, with the spontaneous flow appearing as patterns made up of "convection rolls." These results demonstrate a remarkable richness (including dependence on anchoring conditions) in the steady-state phase behavior of active materials, even in the absence of external forcing; they have no counterpart for passive nematics. Our HLB methodology, which combines lattice Boltzmann for momentum transport with a finite difference scheme for the order parameter dynamics, offers a robust and efficient method for probing the complex hydrodynamic behavior of active nematics.

OPTIMIZATION ON MATERIAL FLOW OF NON-METALIC MINERAL MATERIALS TOWARDS SUSTAINABLE SOCIETY

NASA Astrophysics Data System (ADS)

Sakamoto, Kouji; Nakayama, Hirofumi; Shimaoka, Takayuki; Hasegawa, Ryoji; Osako, Masahiro

Since non-metarilc mineral waste such as concrete mass, asphalt concrete mass, sand, slag and coal ash occupies 36% of total amount of waste generation and 26% of total amount of final disposal, it has significant influence on material flow of our country. Although the amount of non-metaril mineral wastes produced is expected to increase in the near future, demand of their application for recycled construction materials will decrease due to the reduction of public construction works and less use of materials in construction. The aim is to reduce environmental load caused by recycling and disposal of non metallic mineral materials, this study was conducted to evaluate the measurement for the reduction of environmental load like landfill amount and CO2 emission amount by controlling material flow of non metallic mineral materials in the year 2030 by linear programming.

J series thruster isolator failure analysis

NASA Technical Reports Server (NTRS)

Campbell, J. W.; Bechtel, R. T.; Brophy, J. R.

1982-01-01

Three Hg propellant isolators (two cathode and one main) failed during testing in the Mission Profile Life Test. These failures involved contamination of the surface of the alumina insulating body which resulted in heating of the vaporizer by leakage current from the high voltage supply, with subsequent loss of propellant flow rate control. Failure analysis of the isolators showed the surface resistance was temperature dependent and that the alumina could be restored to its original insulating state by grit blasting the surface. The contaminant was identified as carbon and the most likely sources identified as ambient facility hydrocarbons, directed back-sputtered facility materials, and outgassing from organic insulating materials within the thruster envelope. Methods to eliminate contamination from each of these sources are described.

Fluidized bed heat treating system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ripley, Edward B; Pfennigwerth, Glenn L

Systems for heat treating materials are presented. The systems typically involve a fluidized bed that contains granulated heat treating material. In some embodiments a fluid, such as an inert gas, is flowed through the granulated heat treating medium, which homogenizes the temperature of the heat treating medium. In some embodiments the fluid may be heated in a heating vessel and flowed into the process chamber where the fluid is then flowed through the granulated heat treating medium. In some embodiments the heat treating material may be liquid or granulated heat treating material and the heat treating material may be circulatedmore » through a heating vessel into a process chamber where the heat treating material contacts the material to be heat treated. Microwave energy may be used to provide the source of heat for heat treating systems.« less

Proposed industrial recovered materials utilization targets for the metals and metal products industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1979-05-01

Set targets for increased utilization of energy-saving recovered materials in the metals and metal products industries (ferrous, aluminium, copper, zinc, and lead) are discussed. Data preparation and methodology development and analysis of the technological and economic factors in order to prepare draft targets for the use of recovered materials are covered. Chapter 2 provides an introductory discussion of the factors that affect the recovery and reuse of secondary materials and the competition between the primary and secondary metals industries. Chapter 3 presents general profiles for the major industrial segments comprising SIC 33, including industry structure, process technology, materials and recyclingmore » flow, and future trends for the 5 industries: ferrous, aluminium, copper, zinc, and lead. Chapter 4 presents the evaluation of recycling targets for those industries. (MCW)« less