A Systems Analysis of Strike Naval Aviation Training

DTIC Science & Technology

2013-06-01

from external nodes (yellow) and flows through the model design (gray nodes). Arrows represent information flow direction and identify what...multiple times need to be established as external functions accessible by all subroutines • Variables and constants must be defined up-front, and...Downloaded Figure 37. Blocks In Figure 38, proficiency threshold breeches are highlighted to indicate when the resulting skill proficiency drops below the

Double-porosity models for a fissured groundwater reservoir with fracture skin

USGS Publications Warehouse

Moench, Allen F.

1984-01-01

Theories of flow to a well in a double-porosity groundwater reservoir are modified to incorporate effects of a thin layer of low-permeability material or fracture skin that may be present at fracture-block interfaces as a result of mineral deposition or alteration. The commonly used theory for flow in double- porosity formations that is based upon the assumption of pseudo–steady state block-to-fissure flow is shown to be a special case of the theory presented in this paper. The latter is based on the assumption of transient block-to-fissure flow with fracture skin. Under conditions where fracture skin has a hydraulic conductivity that is less than that of the matrix rock, it may be assumed to impede the interchange of fluid between the fissures and blocks. Resistance to flow at fracture-block interfaces tends to reduce spatial variation of hydraulic head gradients within the blocks. This provides theoretical justification for neglecting the divergence of flow in the blocks as required by the pseudo–steady state flow model. Coupled boundary value problems for flow to a well discharging at a constant rate were solved in the Laplace domain. Both slab-shaped and sphere-shaped blocks were considered, as were effects of well bore storage and well bore skin. Results obtained by numerical inversion were used to construct dimensionless-type curves that were applied to well test data, for a pumped well and for an observation well, from the fractured volcanic rock terrane of the Nevada Test Site.

Universal Verification Methodology Based Register Test Automation Flow.

PubMed

Woo, Jae Hun; Cho, Yong Kwan; Park, Sun Kyu

2016-05-01

In today's SoC design, the number of registers has been increased along with complexity of hardware blocks. Register validation is a time-consuming and error-pron task. Therefore, we need an efficient way to perform verification with less effort in shorter time. In this work, we suggest register test automation flow based UVM (Universal Verification Methodology). UVM provides a standard methodology, called a register model, to facilitate stimulus generation and functional checking of registers. However, it is not easy for designers to create register models for their functional blocks or integrate models in test-bench environment because it requires knowledge of SystemVerilog and UVM libraries. For the creation of register models, many commercial tools support a register model generation from register specification described in IP-XACT, but it is time-consuming to describe register specification in IP-XACT format. For easy creation of register model, we propose spreadsheet-based register template which is translated to IP-XACT description, from which register models can be easily generated using commercial tools. On the other hand, we also automate all the steps involved integrating test-bench and generating test-cases, so that designers may use register model without detailed knowledge of UVM or SystemVerilog. This automation flow involves generating and connecting test-bench components (e.g., driver, checker, bus adaptor, etc.) and writing test sequence for each type of register test-case. With the proposed flow, designers can save considerable amount of time to verify functionality of registers.

A general multiblock Euler code for propulsion integration. Volume 1: Theory document

NASA Technical Reports Server (NTRS)

Chen, H. C.; Su, T. Y.; Kao, T. J.

1991-01-01

A general multiblock Euler solver was developed for the analysis of flow fields over geometrically complex configurations either in free air or in a wind tunnel. In this approach, the external space around a complex configuration was divided into a number of topologically simple blocks, so that surface-fitted grids and an efficient flow solution algorithm could be easily applied in each block. The computational grid in each block is generated using a combination of algebraic and elliptic methods. A grid generation/flow solver interface program was developed to facilitate the establishment of block-to-block relations and the boundary conditions for each block. The flow solver utilizes a finite volume formulation and an explicit time stepping scheme to solve the Euler equations. A multiblock version of the multigrid method was developed to accelerate the convergence of the calculations. The generality of the method was demonstrated through the analysis of two complex configurations at various flow conditions. Results were compared to available test data. Two accompanying volumes, user manuals for the preparation of multi-block grids (vol. 2) and for the Euler flow solver (vol. 3), provide information on input data format and program execution.

Simulation of separated flow past a bluff body using Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Ghia, K. N.; Ghia, U.; Osswald, G. A.; Liu, C. A.

1987-01-01

Two-dimensional flow past a bluff body is presently simulated on the basis of an analysis that employs the incompressible, unsteady Navier-Stokes equations in terms of vorticity and stream function. The fully implicit, time-marching, alternating-direction, implicit-block Gaussian elimination used is a direct method with second-order spatial accuracy; this allows it to avoid the introduction of any artificial viscosity. Attention is given to the simulation of flow past a circular cylinder with and without symmetry, requiring the use of either the half or the full cylinder, respectively.

Standard services for the capture, processing, and distribution of packetized telemetry data

NASA Technical Reports Server (NTRS)

Stallings, William H.

1989-01-01

Standard functional services for the capture, processing, and distribution of packetized data are discussed with particular reference to the future implementation of packet processing systems, such as those for the Space Station Freedom. The major functions are listed under the following major categories: input processing, packet processing, and output processing. A functional block diagram of a packet data processing facility is presented, showing the distribution of the various processing functions as well as the primary data flow through the facility.

A Theoretically Informed Model for the Rheology of Entangled Block Copolymer Nanocomposites

NASA Astrophysics Data System (ADS)

Su, Yongrui; Ramirez-Hernandez, Abelardo; Peters, Brandon; de Pablo, Juan J.

2014-03-01

The addition of nanoparticles to block copolymer systems has been shown to have important effects on their equilibrium structure and properties. Less is known about the non-equilibrium behavior of block polymer nanocomposites. A new particle-based, theoretically informed coarse-grained model for multicomponent nanocomposites is proposed to examine the effects of nanoparticles on the rheology of entangled block copolymer melts. Entanglements are treated at the two-molecule level, through slip-springs that couple the dynamics of neighboring pairs of chains. The inclusion of slip-springs changes the polymer dynamics from unentangled to entangled. The nanoparticles are functionalized with short polymer chains that can entangle with the copolymers. We study the nonlinear rheology of the resulting nanocomposites under shear flow with a dissipative particle dynamics (DPD) thermostat.

Modeling and sensitivity analysis on the transport of aluminum oxide nanoparticles in saturated sand: effects of ionic strength, flow rate, and nanoparticle concentration.

PubMed

Rahman, Tanzina; Millwater, Harry; Shipley, Heather J

2014-11-15

Aluminum oxide nanoparticles have been widely used in various consumer products and there are growing concerns regarding their exposure in the environment. This study deals with the modeling, sensitivity analysis and uncertainty quantification of one-dimensional transport of nano-sized (~82 nm) aluminum oxide particles in saturated sand. The transport of aluminum oxide nanoparticles was modeled using a two-kinetic-site model with a blocking function. The modeling was done at different ionic strengths, flow rates, and nanoparticle concentrations. The two sites representing fast and slow attachments along with a blocking term yielded good agreement with the experimental results from the column studies of aluminum oxide nanoparticles. The same model was used to simulate breakthrough curves under different conditions using experimental data and calculated 95% confidence bounds of the generated breakthroughs. The sensitivity analysis results showed that slow attachment was the most sensitive parameter for high influent concentrations (e.g. 150 mg/L Al2O3) and the maximum solid phase retention capacity (related to blocking function) was the most sensitive parameter for low concentrations (e.g. 50 mg/L Al2O3). Copyright © 2014 Elsevier B.V. All rights reserved.

Nuclear reactor reflector

DOEpatents

Hopkins, Ronald J.; Land, John T.; Misvel, Michael C.

1994-01-01

A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled.

Nuclear reactor reflector

DOEpatents

Hopkins, R.J.; Land, J.T.; Misvel, M.C.

1994-06-07

A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled. 12 figs.

Seismic anisotropy beneath the southern Ordos block and the Qinling-Dabie orogen, China: Eastward Tibetan asthenospheric flow around the southern Ordos

NASA Astrophysics Data System (ADS)

Yu, Yong; Chen, Yongshun John

2016-12-01

SKS wave splitting analysis is performed to estimate the seismic anisotropy in the upper mantle using teleseismic data recorded by a temporary seismic array of 180 stations called SOSArray deployed in the southern Ordos block and the Qinling-Dabie orogen. The most important finding is that large delay times with NW-SE fast polarization directions in the northeastern Tibet are continuous across the boundary into the southwestern part of the Ordos block, where the SKS wave splitting results are significantly different from those in the rest of the Ordos block. Based on our SKS wave splitting results in addition to the results from previous studies, we propose an asthenospheric flow model for the eastward extrusion of the Tibetan upper mantle. The model consists of two corner flows around the southwestern corner and the southeastern corner of the Ordos block and the eastward flow along the Weihe graben and the Qinling-Dabie orogen for the escaping Tibetan upper mantle. Finally, the clockwise turning flow of the asthenosphere around the southwestern corner of Ordos block has currently extended laterally into the interior of the Ordos block, suggesting that the thick cold lithospheric root of the southwestern Ordos block there is currently being replaced with hot Tibetan asthenosphere at depths, that is, we observed an on-going process of thermal erosion of a cratonic lithosphere by lateral hot asthenospheric flow.

Gas block mechanism for water removal in fuel cells

DOEpatents

Issacci, Farrokh; Rehg, Timothy J.

2004-02-03

The present invention is directed to apparatus and method for cathode-side disposal of water in an electrochemical fuel cell. There is a cathode plate. Within a surface of the plate is a flow field comprised of interdigitated channels. During operation of the fuel cell, cathode gas flows by convection through a gas diffusion layer above the flow field. Positioned at points adjacent to the flow field are one or more porous gas block mediums that have pores sized such that water is sipped off to the outside of the flow field by capillary flow and cathode gas is blocked from flowing through the medium. On the other surface of the plate is a channel in fluid communication with each porous gas block mediums. The method for water disposal in a fuel cell comprises installing the cathode plate assemblies at the cathode sides of the stack of fuel cells and manifolding the single water channel of each of the cathode plate assemblies to the coolant flow that feeds coolant plates in the stack.

Using colloidal silica as isolator, diverter and blocking agent for subsurface geological applications

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

Bourcier, William L.; Roberts, Sarah K.; Roberts, Jeffery J.

A system for blocking fast flow paths in geological formations includes preparing a solution of colloidal silica having a nonviscous phase and a solid gel phase. The solution of colloidal silica is injected into the geological formations while the solution of colloidal silica is in the nonviscous phase. The solution of colloidal silica is directed into the fast flow paths and reaches the solid gel phase in the fast flow paths thereby blocking flow of fluid in the fast paths.

Kennedy Space Center Orion Processing Team Planning for Ground Operations

NASA Technical Reports Server (NTRS)

Letchworth, Gary; Schlierf, Roland

2011-01-01

Topics in this presentation are: Constellation Ares I/Orion/Ground Ops Elements Orion Ground Operations Flow Orion Operations Planning Process and Toolset Overview, including: 1 Orion Concept of Operations by Phase 2 Ops Analysis Capabilities Overview 3 Operations Planning Evolution 4 Functional Flow Block Diagrams 5 Operations Timeline Development 6 Discrete Event Simulation (DES) Modeling 7 Ground Operations Planning Document Database (GOPDb) Using Operations Planning Tools for Operability Improvements includes: 1 Kaizen/Lean Events 2 Mockups 3 Human Factors Analysis

Comparison of three techniques for generation of tolerogenic dendritic cells: siRNA, oligonucleotide antisense, and antibody blocking.

PubMed

Karimi, Mohammad Hossein; Ebadi, Padideh; Pourfathollah, Ali Akbar; Moazzeni, Mohammad; Soheili, Zahra Soheila; Samiee, Shahram

2010-12-01

In recent years, a new view of dendritic cells (DCs) as a main regulator of immunity to induce and maintain tolerance has been established. In vitro manipulation of their development and maturation is a topic of DC therapeutic application, which utilizes their inherent tolerogenicity. In this field, the therapeutic potential of antisense, siRNA, and blocking antibody are an interesting goal. In the present study, the efficiency of these three methods--siRNA, antisense, and blocking antibody--against CD40 molecule and its function in DCs and BCL1 cell line are compared. DCs were separated from mouse spleen and then cultured in vitro using Lipofectamine 2000 to deliver both silencers; the efficacy of transfection was estimated by flow cytometry. mRNA expression and protein synthesis were assessed by real time-PCR and flow cytometry, respectively. By Annexin V and propidium iodine staining, we could evaluate the viability of transfected cells. Knocking down the CD40 gene into separate groups of DCs by siRNA, antisense, and blocking antibody treated DCs can cause an increase in IL-4, decrease in IL-12, IFN-γ production, and allostimulation activity. Our results indicated that, in comparison to antisense and blocking antibody, siRNAs appear to be quantitatively more efficient in CD40 downregulation and their differences are significant.

Axillary brachial plexus block duration with mepivacaine in patients with chronic renal failure. Case-control study.

PubMed

Mojica, V; Nieuwveld, D; Herrera, A E; Mestres, G; López, A M; Sala-Blanch, X

2017-04-01

Regional anaesthesia is commonly preferred for arteriovenous fistula (AVF) creation. Previous studies suggest a shorter block duration in patients with chronic renal failure, maybe because of the changes in regional blood flow. The aim of our study was to evaluate the duration of the axillary block with 1.5% mepivacaine in patients with chronic renal failure scheduled for AVF compared with healthy controls. Patients scheduled for AVF creation for the first time (GIRC) were included. They were compared with patients without renal failure (GC), with similar anthropometric characteristics. Ultrasound-guided axillary blocks with 20mL of 1.5% mepivacaine were performed on all patients. We evaluated onset time, humeral artery diameter and blood flow before and after the block, as well as the block duration. Twenty-three patients (GIRC: 12 and GC: 11) were included. No differences between groups were observed in block duration (GIRC: 227±43min vs GC: 229±27min; P=.781), or in onset time (GIRC: 13±5min vs GC: 12.2±3min; P=.477). The humeral blood flow before and after block was significantly lower in the GIRC (pre-block: GIRC: 52±21ml/min GC: 100±62ml/min; P=.034 and p ost block: GIRC: 130±57ml/min and GC: 274±182ml/min; P=.010). There was no significant correlation between the duration of the block and the preblock humeral blood flow (Spearman Rho: 0.106; P=.657) or the postblock humeral blood flow (Spearman Rho: 0.267; P=.254). The duration of the axillary block with 1.5% mepivacaine in patients with chronic renal failure was similar to that of the control patients. The duration of axillary brachial plexus block seems not to be related to changes in regional blood flow. Copyright © 2016 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Integrins are Mechanosensors That Modulate Human Eosinophil Activation

PubMed Central

Ahmadzai, Mustafa; Small, Mike; Sehmi, Roma; Gauvreau, Gail; Janssen, Luke J.

2015-01-01

Eosinophil migration to the lung is primarily regulated by the eosinophil-selective family of eotaxin chemokines, which mobilize intracellular calcium (Ca2+) and orchestrate myriad changes in cell structure and function. Eosinophil function is also known to be flow-dependent, although the molecular cognate of this mechanical response has yet to be adequately characterized. Using confocal fluorescence microscopy, we determined the effects of fluid shear stress on intracellular calcium concentration ([Ca2+]i) in human peripheral blood eosinophils by perfusing cells in a parallel-plate flow chamber. Our results indicate that fluid perfusion evokes a calcium response that leads to cell flattening, increase in cell area, shape change, and non-directional migration. None of these changes are seen in the absence of a flow stimulus, and all are blocked by chelation of intracellular Ca2+ using BAPTA. These changes are enhanced by stimulating the cells with eotaxin-1. The perfusion-induced calcium response (PICR) could be blocked by pre-treating cells with selective (CDP-323) and non-selective (RGD tripeptides) integrin receptor antagonists, suggesting that α4β7/α4β1 integrins mediate this response. Overall, our study provides the first pharmacological description of a molecular mechanosensor that may collaborate with the eotaxin-1 signaling program in order to control human eosinophil activation. PMID:26539194

A block iterative finite element algorithm for numerical solution of the steady-state, compressible Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Cooke, C. H.

1976-01-01

An iterative method for numerically solving the time independent Navier-Stokes equations for viscous compressible flows is presented. The method is based upon partial application of the Gauss-Seidel principle in block form to the systems of nonlinear algebraic equations which arise in construction of finite element (Galerkin) models approximating solutions of fluid dynamic problems. The C deg-cubic element on triangles is employed for function approximation. Computational results for a free shear flow at Re = 1,000 indicate significant achievement of economy in iterative convergence rate over finite element and finite difference models which employ the customary time dependent equations and asymptotic time marching procedure to steady solution. Numerical results are in excellent agreement with those obtained for the same test problem employing time marching finite element and finite difference solution techniques.

A new estimation of equivalent matrix block sizes in fractured media with two-phase flow applications in dual porosity models

NASA Astrophysics Data System (ADS)

Jerbi, Chahir; Fourno, André; Noetinger, Benoit; Delay, Frederick

2017-05-01

Single and multiphase flows in fractured porous media at the scale of natural reservoirs are often handled by resorting to homogenized models that avoid the heavy computations associated with a complete discretization of both fractures and matrix blocks. For example, the two overlapping continua (fractures and matrix) of a dual porosity system are coupled by way of fluid flux exchanges that deeply condition flow at the large scale. This characteristic is a key to realistic flow simulations, especially for multiphase flow as capillary forces and contrasts of fluid mobility compete in the extraction of a fluid from a capacitive matrix then conveyed through the fractures. The exchange rate between fractures and matrix is conditioned by the so-called mean matrix block size which can be viewed as the size of a single matrix block neighboring a single fracture within a mesh of a dual porosity model. We propose a new evaluation of this matrix block size based on the analysis of discrete fracture networks. The fundaments rely upon establishing at the scale of a fractured block the equivalence between the actual fracture network and a Warren and Root network only made of three regularly spaced fracture families parallel to the facets of the fractured block. The resulting matrix block sizes are then compared via geometrical considerations and two-phase flow simulations to the few other available methods. It is shown that the new method is stable in the sense it provides accurate sizes irrespective of the type of fracture network investigated. The method also results in two-phase flow simulations from dual porosity models very close to that from references calculated in finely discretized networks. Finally, calculations of matrix block sizes by this new technique reveal very rapid, which opens the way to cumbersome applications such as preconditioning a dual porosity approach applied to regional fractured reservoirs.

Estimation of additive forces and moments for supersonic inlets

NASA Technical Reports Server (NTRS)

Perkins, Stanley C., Jr.; Dillenius, Marnix F. E.

1991-01-01

A technique for estimating the additive forces and moments associated with supersonic, external compression inlets as a function of mass flow ratio has been developed. The technique makes use of a low order supersonic paneling method for calculating minimum additive forces at maximum mass flow conditions. A linear relationship between the minimum additive forces and the maximum values for fully blocked flow is employed to obtain the additive forces at a specified mass flow ratio. The method is applicable to two-dimensional inlets at zero or nonzero angle of attack, and to axisymmetric inlets at zero angle of attack. Comparisons with limited available additive drag data indicate fair to good agreement.

Fuel control for gas turbine engines

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

Stearns, C.F.; Tutherly, H.W.

1983-12-27

The basic gas turbine engine hydromechanical fuel control is adaptable to different engine configurations such as turbofan, turboprop and turboshaft engines by incorporating in the main housing those elements having a commonality to all engine configurations and providing a removable block for each configuration having the necessary control elements and flow passages required for that particular configuration. That is to say, a block with the elements peculiar to a turbofan engine could be replaced by a mating block that includes those elements peculiar to a turboshaft engine in adapting the control for a turboshaft configuration. Similarly another block with thosemore » elements peculiar to a turboprop engine could replace any of the other blocks in adapting the control to a turboprop configuration. Obviously the basic control has the necessary flow passages terminating at the interface with the block and these flow passages mate with corresponding passages in the block.« less

Atmospheric Blocking and Intercomparison of Objective Detection Methods: Flow Field Characteristics

NASA Astrophysics Data System (ADS)

Pinheiro, M. C.; Ullrich, P. A.; Grotjahn, R.

2017-12-01

A number of objective methods for identifying and quantifying atmospheric blocking have been developed over the last couple of decades, but there is variable consensus on the resultant blocking climatology. This project examines blocking climatologies as produced by three different methods: two anomaly-based methods, and the geopotential height gradient method of Tibaldi and Molteni (1990). The results highlight the differences in blocking that arise from the choice of detection method, with emphasis on the physical characteristics of the flow field and the subsequent effects on the blocking patterns that emerge.

Thulium-170 heat source

DOEpatents

Walter, Carl E.; Van Konynenburg, Richard; VanSant, James H.

1992-01-01

An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

Computational analysis of electrokinetically driven flow mixing in microchannels with patterned blocks

NASA Astrophysics Data System (ADS)

Chang, C.-C.; Yang, R.-J.

2004-04-01

Electroosmotic flow in microchannels is restricted to low Reynolds number regimes characterized by extremely weak inertia forces and laminar flow. Consequently, the mixing of different species occurs primarily through diffusion, and hence cannot readily be achieved within a short mixing channel. The current study presents a numerical investigation of electrokinetically driven flow mixing in microchannels with various numbers of incorporated patterned rectangular blocks. Furthermore, a novel approach is introduced which patterns heterogeneous surfaces on the upper faces of these rectangular blocks in order to enhance species mixing. The simulation results confirm that the introduction of rectangular blocks within the mixing channel slightly enhances species mixing by constricting the bulk flow, hence creating a stronger diffusion effect. However, it is noted that a large number of blocks and hence a long mixing channel are required if a complete mixing of the species is to be obtained. The results also indicate that patterning heterogeneous upper surfaces on the rectangular blocks is an effective means of enhancing the species mixing. It is shown that increasing the magnitude of the heterogeneous surface zeta potential enables a reduction in the mixing channel length and an improved degree of mixing efficiency.

Flank collapse at Mount Wrangell, Alaska, recorded by volcanic mass-flow deposits in the Copper River lowland

USGS Publications Warehouse

Waythomas, C.F.; Wallace, K.L.

2002-01-01

An areally extensive volcanic mass-flow deposit of Pleistocene age, known as the Chetaslina volcanic mass-flow deposit, is a prominent and visually striking deposit in the southeastern Copper River lowland of south-central Alaska. The mass-flow deposit consists of a diverse mixture of colorful, variably altered volcanic rocks, lahar deposits, glaciolacustrine diamicton, and till that record a major flank collapse on the southwest flank of Mount Wrangell. The deposit is well exposed near its presumed source, and thick, continuous, stratigraphic exposures have permitted us to study its sedimentary characteristics as a means of better understanding the origin, significance, and evolution of the deposit. Deposits of the Chetaslina volcanic mass flow in the Chetaslina River drainage are primary debris-avalanche deposits and consist of two principal facies types, a near-source block facies and a distal mixed facies. The block facies is composed entirely of block-supported, shattered and fractured blocks with individual blocks up to 40 m in diameter. The mixed facies consists of block-sized particles in a matrix of poorly sorted rock rubble, sand, and silt generated by the comminution of larger blocks. Deposits of the Chetaslina volcanic mass flow exposed along the Copper, Tonsina, and Chitina rivers are debris-flow deposits that evolved from the debris-avalanche component of the flow and from erosion and entrainment of local glacial and glaciolacustrine diamicton in the Copper River lowland. The debris-flow deposits were probably generated through mixing of the distal debris avalanche with the ancestral Copper River, or through breaching of a debris-avalanche dam across the ancestral river. The distribution of facies types and major-element chemistry of clasts in the deposit indicate that its source was an ancestral volcanic edifice, informally known as the Chetaslina vent, on the southwest side of Mount Wrangell. A major sector collapse of the Chetaslina vent initiated the Chetaslina volcanic mass flow forming a debris avalanche of about 4 km3 that subsequently transformed to a debris flow of unknown volume.

Phosphorylation status modulates Bcl-2 function during glucocorticoid-induced apoptosis in T lymphocytes.

PubMed

Huang, Se-Te J; Cidlowski, John A

2002-06-01

Glucocorticoids are known to induce apoptosis in lymphoid cells, and Bcl-2 overexpression can block the apoptosis-inducing action of glucocorticoids. Since phosphorylation of Bcl-2 is implicated in regulating Bcl-2 function, we considered the role of Bcl-2 phosphorylation in protecting lymphoid cells from glucocorticoid-induced cell death. Five stably transfected cell lines of WEHI 7.1 cells expressing either wild-type Bcl-2 or alanine mutants of Bcl-2 at amino acids threonine 56, serine 70, threonine 74, or serine 87 were created. Expression of the mutant Bcl-2 proteins was documented by flow cytometry and Western blot analysis. Mutation of Bcl-2 on T56 and S87 eliminated the ability of Bcl-2 to inhibit glucocorticoid-induced cell shrinkage, mitochondrial depolarization, DNA fragmentation, and cell death. Mutation of T74 only partially impaired the ability of Bcl-2 to block glucocorticoid-induced apoptosis whereas mutation of S70 in Bcl-2 did not alter its ability to block glucocorticoid-induced apoptosis.

MHD natural convection and entropy generation in an open cavity having different horizontal porous blocks saturated with a ferrofluid

NASA Astrophysics Data System (ADS)

Gibanov, Nikita S.; Sheremet, Mikhail A.; Oztop, Hakan F.; Al-Salem, Khaled

2018-04-01

In this study, natural convection combined with entropy generation of Fe3O4-water nanofluid within a square open cavity filled with two different porous blocks under the influence of uniform horizontal magnetic field is numerically studied. Porous blocks of different thermal properties, permeability and porosity are located on the bottom wall. The bottom wall of the cavity is kept at hot temperature Th, while upper open boundary is at constant cold temperature Tc and other walls of the cavity are supposed to be adiabatic. Governing equations with corresponding boundary conditions formulated in dimensionless stream function and vorticity using Brinkman-extended Darcy model for porous blocks have been solved numerically using finite difference method. Numerical analysis has been carried out for wide ranges of Hartmann number, nanoparticles volume fraction and length of the porous blocks. It has been found that an addition of spherical ferric oxide nanoparticles can order the flow structures inside the cavity.

An incremental block-line-Gauss-Seidel method for the Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Napolitano, M.; Walters, R. W.

1985-01-01

A block-line-Gauss-Seidel (LGS) method is developed for solving the incompressible and compressible Navier-Stokes equations in two dimensions. The method requires only one block-tridiagonal solution process per iteration and is consequently faster per step than the linearized block-ADI methods. Results are presented for both incompressible and compressible separated flows: in all cases the proposed block-LGS method is more efficient than the block-ADI methods. Furthermore, for high Reynolds number weakly separated incompressible flow in a channel, which proved to be an impossible task for a block-ADI method, solutions have been obtained very efficiently by the new scheme.

Deployable Emergency Shutoff Device Blocks High-Velocity Fluid Flows

NASA Technical Reports Server (NTRS)

Nabors, Sammy A.

2015-01-01

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

Radio-tracer techniques for the study of flow in saturated porous materials

USGS Publications Warehouse

Skibitzke, H.E.; Chapman, H.T.; Robinson, G.M.; McCullough, Richard A.

1961-01-01

An experiment was conducted by the U.S. Geological Survey to determine the feasibility of using a radioactive substance as a tracer in the study of microscopic flow in a saturated porous solid. A radioactive tracer was chosen in preference to dye or other chemical in order to eliminate effects of the tracer itself on the flow system such as those relating to density, viscosity and surface tension. The porous solid was artificial "sandstone" composed of uniform fine grains of sand bonded together with an epoxy adhesive. The sides of the block thus made were sealed with an epoxy coating compound to insure water-tightness. Because of the chemical inertness of the block it was possible to use radioactive phosphorus (P32). Ion-exchange equilibrium was created between the block and nonradioactive phosphoric acid. Then a tracer tagged with P32 was injected into the block in the desired geometric configuration, in this case, a line source. After equilibrium in isotopic exchange was reached between the block and the line source, the block was rinsed, drained and sawn into slices. It was found that a quantitative analysis of the flow system may be made by assaying the dissected block. ?? 1961.

Hemorrhoid surgery

MedlinePlus

... a small rubber band around a hemorrhoid to shrink it by blocking blood flow. Stapling a hemorrhoid to block blood flow, causing it to shrink. Using a knife (scalpel) to remove hemorrhoids. You ...

Experimental investigation and CFD analysis on cross flow in the core of PMR200

DOE PAGES

Lee, Jeong -Hun; Yoon, Su -Jong; Cho, Hyoung -Kyu; ...

2015-04-16

The Prismatic Modular Reactor (PMR) is one of the major Very High Temperature Reactor (VHTR) concepts, which consists of hexagonal prismatic fuel blocks and reflector blocks made of nuclear gradegraphite. However, the shape of the graphite blocks could be easily changed by neutron damage duringthe reactor operation and the shape change can create gaps between the blocks inducing the bypass flow.In the VHTR core, two types of gaps, a vertical gap and a horizontal gap which are called bypass gap and cross gap, respectively, can be formed. The cross gap complicates the flow field in the reactor core by connectingmore » the coolant channel to the bypass gap and it could lead to a loss of effective coolant flow in the fuel blocks. Thus, a cross flow experimental facility was constructed to investigate the cross flow phenomena in the core of the VHTR and a series of experiments were carried out under varying flow rates and gap sizes. The results of the experiments were compared with CFD (Computational Fluid Dynamics) analysis results in order to verify its prediction capability for the cross flow phenomena. Fairly good agreement was seen between experimental results and CFD predictions and the local characteristics of the cross flow was discussed in detail. Based on the calculation results, pressure loss coefficient across the cross gap was evaluated, which is necessary for the thermo-fluid analysis of the VHTR core using a lumped parameter code.« less

A new lumped-parameter model for flow in unsaturated dual-porosity media

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

Zimmerman, Robert W.; Hadgu, Teklu; Bodvarsson, Gudmundur S.

A new lumped-parameter approach to simulating unsaturated flow processes in dual-porosity media such as fractured rocks or aggregated soils is presented. Fluid flow between the fracture network and the matrix blocks is described by a non-linear equation that relates the imbibition rate to the local difference in liquid-phase pressure between the fractures and the matrix blocks. Unlike a Warren-Root-type equation, this equation is accurate in both the early and late time regimes. The fracture/matrix interflow equation has been incorporated into an existing unsaturated flow simulator, to serve as a source/sink term for fracture gridblocks. Flow processes are then simulated usingmore » only fracture gridblocks in the computational grid. This new lumped-parameter approach has been tested on two problems involving transient flow in fractured/porous media, and compared with simulations performed using explicit discretization of the matrix blocks. The new procedure seems to accurately simulate flow processes in unsaturated fractured rocks, and typically requires an order of magnitude less computational time than do simulations using fully-discretized matrix blocks. [References: 37]« less

Domain modeling and grid generation for multi-block structured grids with application to aerodynamic and hydrodynamic configurations

NASA Technical Reports Server (NTRS)

Spekreijse, S. P.; Boerstoel, J. W.; Vitagliano, P. L.; Kuyvenhoven, J. L.

1992-01-01

About five years ago, a joint development was started of a flow simulation system for engine-airframe integration studies on propeller as well as jet aircraft. The initial system was based on the Euler equations and made operational for industrial aerodynamic design work. The system consists of three major components: a domain modeller, for the graphical interactive subdivision of flow domains into an unstructured collection of blocks; a grid generator, for the graphical interactive computation of structured grids in blocks; and a flow solver, for the computation of flows on multi-block grids. The industrial partners of the collaboration and NLR have demonstrated that the domain modeller, grid generator and flow solver can be applied to simulate Euler flows around complete aircraft, including propulsion system simulation. Extension to Navier-Stokes flows is in progress. Delft Hydraulics has shown that both the domain modeller and grid generator can also be applied successfully for hydrodynamic configurations. An overview is given about the main aspects of both domain modelling and grid generation.

Assessment of Environmental Flows for the Rivers of Western Ganges Delta with Special Reference to Indian Sundarban

NASA Astrophysics Data System (ADS)

Bhadra, T.; Hazra, S.; Ghosh, S.; Barman, B. C.

2016-12-01

The Indian Sundarban, situated on the western tide-dominated part of the Ganges delta was formed by the sedimentation of the Ganges and its tributaries. Freshwater is a scarce resource in the Sundarban though it is traversed by rivers. Most of the rivers of Western Ganges Delta, which used to nourish the Sundarban, have become defunct with the passage of time. To ensure sustainable flow and to enhance the flow-dependent ecosystem services in this region, assessment of environmental flows within the system is required. A pilot assessment of environment flows, supported by IUCN has been carried out in some specific river reaches of Western Ganges Delta under the present study. The holistic Building Block Methodology (BBM) has been modified and used for the assessment of environmental flows. In the modified BBM, three distinctive blocks namely Hydro-Morphology, Ecology and Socio-Economy have been selected and indicators like Ganges Dolphin (Platanista gangetica), Sundari tree (Heritiera fomes) and Hilsa fish (Tenualosa ilisha) etc. have been determined to assess the environmental flows. As the discharge data of the selected rivers are restricted in the public domain, the SWAT model has been run to generate the discharge data of the classified rivers. The Hydraulic model, HEC-RAS has been calibrated in the selected River reaches to assess the habitat availability and its changes for indicator species under different flow condition. The study reveals that River Bhagirathi-Hugli requires 150-427 cumec additional water in monsoon and 850-1127 cumec additional water in post-monsoon months for Hilsa migration, whereas 327-486 cumec additional water in pre-monsoon and dry season and 227-386 cumec additional water in post-monsoon months are required for Dolphin movement. Flow requirement of river Ichhamati has also been estimated under the present study. The total required flow for the Sundarban ecosystem to reduce the salinity level from 30ppt to 14ppt during the dry and pre-monsoon months has been estimated as 1700 cumec. The pilot study observes that the present level of flow in the river systems is inadequate to sustain the ecosystem function and the in-stream flow requirement is more than the presently available flow. Keyword: Building Block Methodology, Environmental Flows, HEC-RAS, Indian Sundarban, SWAT.

A project management system for the X-29A flight test program

NASA Technical Reports Server (NTRS)

Stewart, J. F.; Bauer, C. A.

1983-01-01

The project-management system developed for NASA's participation in the X-29A aircraft development program is characterized from a theoretical perspective, as an example of a system appropriate to advanced, highly integrated technology projects. System-control theory is applied to the analysis of classical project-management techniques and structures, which are found to be of closed-loop multivariable type; and the effects of increasing project complexity and integration are evaluated. The importance of information flow, sampling frequency, information holding, and delays is stressed. The X-29A system is developed in four stages: establishment of overall objectives and requirements, determination of information processes (block diagrams) definition of personnel functional roles and relationships, and development of a detailed work-breakdown structure. The resulting system is shown to require a greater information flow to management than conventional methods. Sample block diagrams are provided.

Bulk rheology and simulated episodic tremor and slip within a numerically-modeled block-dominated subduction melange

NASA Astrophysics Data System (ADS)

Webber, S.; Ellis, S. M.; Fagereng, A.

2015-12-01

We investigate the influence of melange rheology in a subduction thrust interface on stress and slip cycling constrained by observations from an exhumed subduction complex at Chrystalls Beach, New Zealand. A two-phase mélange dominated by large, competent brittle-viscous blocks surrounded by a weak non-linear viscous matrix is numerically modeled, and the evolution of bulk stress are analysed as the domain deforms. The models produce stress cycling behaviour under constant shear strain rate boundary conditions for a wide range of physical conditions that roughly corresponds to depths and strain rates calculated for instrumentally observed episodic tremor and slip (ETS) in presently-deforming subduction thrust interfaces. Stress cycling is accompanied by mixed brittle plastic-viscous deformation, and occurs as a consequence of geometric reorganisation and the progressive development and breakdown of stress bridges as blocks mutually obstruct one another. We argue that periods of low differential stress correspond to periods of rapid mixed-mode deformation and ETS. Stress cycling episodicities are a function of shear strain rate and pressure/temperature conditions at depth. The time period of stress cycling is principally controlled by the geometry (block distribution and density through time) and stress cycling amplitudes are controlled by effective stress. The duration of stress cycling events in the models (months-years) and rapid strain rates are comparable to instrumentally observed ETS. Shear strain rates are 1 - 2 orders of magnitude slower between stress cycling events, suggesting episodic return times within a single model domain are long duration (> centennial timescales), assuming constant flow stress. Finally, we derive a bulk viscous flow law for block dominated subduction mélanges for conditions 300 - 500°C and elevated pore fluid pressures. Bulk flow laws calculated for block-dominated subduction mélanges are non-linear, owing to a combination of non-linear matrix viscosity and development of tensile fractures at rapid shear strain rates. Model behaviour, including the generation of mixed-mode deformation, is highly comparable to the exhumed block-dominated melange found within the Chrystalls Beach Complex.

Duct flow nonuniformities: Effect of struts in SSME HGM II(+)

NASA Technical Reports Server (NTRS)

Burke, Roger

1988-01-01

A numerical study, using the INS3D flow solver, of laminar and turbulent flow around a two dimensional strut, and three dimensional flow around a strut in an annulus is presented. A multi-block procedure was used to calculate two dimensional laminar flow around two struts in parallel, with each strut represented by one computational block. Single block calculations were performed for turbulent flow around a two dimensional strut, using a Baldwin-Lomax turbulence model to parameterize the turbulent shear stresses. A modified Baldwin-Lomax model was applied to the case of a three dimensional strut in an annulus. The results displayed the essential features of wing-body flows, including the presence of a horseshoe vortex system at the junction of the strut and the lower annulus surface. A similar system was observed at the upper annulus surface. The test geometries discussed were useful in developing the capability to perform multiblock calculations, and to simulate turbulent flow around obstructions located between curved walls. Both of these skills will be necessary to model the three dimensional flow in the strut assembly of the SSME. Work is now in progress on performing a three dimensional two block turbulent calculation of the flow in the turnaround duct (TAD) and strut/fuel bowl juncture region.

Comparison of Diaphragmatic Breathing Exercise, Volume and Flow Incentive Spirometry, on Diaphragm Excursion and Pulmonary Function in Patients Undergoing Laparoscopic Surgery: A Randomized Controlled Trial

PubMed Central

Anand, R.

2016-01-01

Objective. To evaluate the effects of diaphragmatic breathing exercises and flow and volume-oriented incentive spirometry on pulmonary function and diaphragm excursion in patients undergoing laparoscopic abdominal surgery. Methodology. We selected 260 patients posted for laparoscopic abdominal surgery and they were block randomization as follows: 65 patients performed diaphragmatic breathing exercises, 65 patients performed flow incentive spirometry, 65 patients performed volume incentive spirometry, and 65 patients participated as a control group. All of them underwent evaluation of pulmonary function with measurement of Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Peak Expiratory Flow Rate (PEFR), and diaphragm excursion measurement by ultrasonography before the operation and on the first and second postoperative days. With the level of significance set at p < 0.05. Results. Pulmonary function and diaphragm excursion showed a significant decrease on the first postoperative day in all four groups (p < 0.001) but was evident more in the control group than in the experimental groups. On the second postoperative day pulmonary function (Forced Vital Capacity) and diaphragm excursion were found to be better preserved in volume incentive spirometry and diaphragmatic breathing exercise group than in the flow incentive spirometry group and the control group. Pulmonary function (Forced Vital Capacity) and diaphragm excursion showed statistically significant differences between volume incentive spirometry and diaphragmatic breathing exercise group (p < 0.05) as compared to that flow incentive spirometry group and the control group. Conclusion. Volume incentive spirometry and diaphragmatic breathing exercise can be recommended as an intervention for all patients pre- and postoperatively, over flow-oriented incentive spirometry for the generation and sustenance of pulmonary function and diaphragm excursion in the management of laparoscopic abdominal surgery. PMID:27525116

Comparison of Diaphragmatic Breathing Exercise, Volume and Flow Incentive Spirometry, on Diaphragm Excursion and Pulmonary Function in Patients Undergoing Laparoscopic Surgery: A Randomized Controlled Trial.

PubMed

Alaparthi, Gopala Krishna; Augustine, Alfred Joseph; Anand, R; Mahale, Ajith

2016-01-01

Objective. To evaluate the effects of diaphragmatic breathing exercises and flow and volume-oriented incentive spirometry on pulmonary function and diaphragm excursion in patients undergoing laparoscopic abdominal surgery. Methodology. We selected 260 patients posted for laparoscopic abdominal surgery and they were block randomization as follows: 65 patients performed diaphragmatic breathing exercises, 65 patients performed flow incentive spirometry, 65 patients performed volume incentive spirometry, and 65 patients participated as a control group. All of them underwent evaluation of pulmonary function with measurement of Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Peak Expiratory Flow Rate (PEFR), and diaphragm excursion measurement by ultrasonography before the operation and on the first and second postoperative days. With the level of significance set at p < 0.05. Results. Pulmonary function and diaphragm excursion showed a significant decrease on the first postoperative day in all four groups (p < 0.001) but was evident more in the control group than in the experimental groups. On the second postoperative day pulmonary function (Forced Vital Capacity) and diaphragm excursion were found to be better preserved in volume incentive spirometry and diaphragmatic breathing exercise group than in the flow incentive spirometry group and the control group. Pulmonary function (Forced Vital Capacity) and diaphragm excursion showed statistically significant differences between volume incentive spirometry and diaphragmatic breathing exercise group (p < 0.05) as compared to that flow incentive spirometry group and the control group. Conclusion. Volume incentive spirometry and diaphragmatic breathing exercise can be recommended as an intervention for all patients pre- and postoperatively, over flow-oriented incentive spirometry for the generation and sustenance of pulmonary function and diaphragm excursion in the management of laparoscopic abdominal surgery.

Angiotensin converting enzyme inhibitors and aortic arch obstructive malformations.

PubMed

Maliheh, Kadivar; Abdorrazagh, Kiani; Armen, Kocharian; Reza, Shabanian

2006-10-01

We describe two newborn infants with aortic arch obstructive malformations who became anuric after initiation of captopril. Since angiotensin converting enzyme inhibitors can alter renal blood flow by reduction in angiotensin II and blocking autoregulation phenomenon, it is important to use them with great caution in neonates with aortic arch obstructive malformations, while monitoring their renal function closely.

Fluvial entrainment of low density peat blocks (block carbon)

NASA Astrophysics Data System (ADS)

Warburton, Jeff

2014-05-01

In many fluvial environments low density materials are transported in significant quantities and these form an important part of the stream load and /or have a distinct impact on sedimentation in these environments. However, there are significant gaps in understanding of how these materials are entrained and transported by streams and rivers. Eroding upland peatland environments in particular, frequently have fluvial systems in which large eroded peat blocks, often exceeding 1 m in length; form an important component of the stream material flux. Transport of this material is significant in determining rates of erosion but also has important impacts in terms of damage to infrastructure and carbon loss. This paper describes a field experiment designed to establish for the first time the conditions under which large peat blocks (c. > 0.1 m b axis) are initially entrained from a rough gravel bed. The field site is Trout Beck, in the North Pennines, Northern England which is an upland wandering river channel with occasional lateral and mid channel bars. Mean low flow stage is typically 0.2 m but during flood can rapidly rise, in one to two hours, to over 1.5 m. To study peat block entrainment a bespoke data acquisition system consisting of two pressure transducers, four release triggers and time lapse camera was set up. The pressure transducers provided a record of local depth and the release triggers were embedded in peat blocks to record initial motion and arranged on the rough stream bed. The time lapse camera provided verification of timing of block entrainment (during daylight hours) and also provided information on the mechanism of initial movement. Peat blocks were cut from a local source and were equidimensional, ranging in size from 0.1 to 0.7 m. The derived entrainment function is related to a critical depth of entrainment. Results demonstrate that peat blocks are entrained when the local depth approximates the height of the peat block. Blocks frequently shift position prior to entrainment but once entrained are rapidly transported downstream. Because of the rough stream bed local depth, measured on the four sides of the block varies markedly and needs to be considered in developing an appropriate entrainment function and; is useful in explaining initial movement prior to entrainment. In some experiments a small accelerometer (HOBO Pendant G data logger) was used to investigate transport dynamics following entrainment. Further work will seek to improve the entrainment function by extending the size range of tests, developing a shear stress related function and investigating the importance of block shape (rounding) on entrainment.

Three-dimensional Reconstruction of Block Shape Irregularity and its Effects on Block Impacts Using an Energy-Based Approach

NASA Astrophysics Data System (ADS)

Zhang, Yulong; Liu, Zaobao; Shi, Chong; Shao, Jianfu

2018-04-01

This study is devoted to three-dimensional modeling of small falling rocks in block impact analysis in energy view using the particle flow method. The restitution coefficient of rockfall collision is introduced from the energy consumption mechanism to describe rockfall-impacting properties. Three-dimensional reconstruction of falling block is conducted with the help of spherical harmonic functions that have satisfactory mathematical properties such as orthogonality and rotation invariance. Numerical modeling of the block impact to the bedrock is analyzed with both the sphere-simplified model and the 3D reconstructed model. Comparisons of the obtained results suggest that the 3D reconstructed model is advantageous in considering the combination effects of rockfall velocity and rotations during colliding process. Verification of the modeling is carried out with the results obtained from other experiments. In addition, the effects of rockfall morphology, surface characteristics, velocity, and volume, colliding damping and relative angle are investigated. A three-dimensional reconstruction modulus of falling blocks is to be developed and incorporated into the rockfall simulation tools in order to extend the modeling results at block scale to slope scale.

Blood clots are rapidly assembled hemodynamic sensors: flow arrest triggers intraluminal thrombus contraction.

PubMed

Muthard, Ryan W; Diamond, Scott L

2012-12-01

Blood clots form under flow during intravascular thrombosis or vessel leakage. Prevailing hemodynamics influence thrombus structure and may regulate contraction processes. A microfluidic device capable of flowing human blood over a side channel plugged with collagen (± tissue factor) was used to measure thrombus permeability (κ) and contraction at controlled transthrombus pressure drops. The collagen (κ(collagen)=1.98 × 10(-11) cm(2)) supported formation of a 20-µm thick platelet layer, which unexpectedly underwent massive platelet retraction on flow arrest. This contraction resulted in a 5.34-fold increase in permeability because of collagen restructuring. Without stopping flow, platelet deposits (no fibrin) had a permeability of κ(platelet)=5.45 × 10(-14) cm(2) and platelet-fibrin thrombi had κ(thrombus)=2.71 × 10(-14) cm(2) for ΔP=20.7 to 23.4 mm Hg, the first ever measurements for clots formed under arterial flow (1130 s(-1) wall shear rate). Platelet sensing of flow cessation triggered a 4.6- to 6.5-fold (n=3, P<0.05) increase in contraction rate, which was also observed in a rigid, impermeable parallel-plate microfluidic device. This triggered contraction was blocked by the myosin IIA inhibitor blebbistatin and by inhibitors of thromboxane A2 (TXA(2)) and ADP signaling. In addition, flow arrest triggered platelet intracellular calcium mobilization, which was blocked by TXA(2)/ADP inhibitors. As clots become occlusive or blood pools following vessel leakage, the flow diminishes, consequently allowing full platelet retraction. Flow dilution of ADP and thromboxane regulates platelet contractility with prevailing hemodynamics, a newly defined flow-sensing mechanism to regulate clot function.

Blood clots are rapidly assembled hemodynamic sensors: Flow arrest triggers intraluminal thrombus contraction

PubMed Central

Muthard, Ryan W.; Diamond, Scott L.

2012-01-01

Objective Blood clots form under flow during intravascular thrombosis or vessel leakage. Prevailing hemodynamics influence thrombus structure and may regulate contraction processes. A microfluidic device capable of flowing human blood over a side channel plugged with collagen (± tissue factor) was used to measure thrombus permeability (κ) and contraction at controlled transthrombus pressure drops. Methods and Results The collagen (κcollagen = 1.98 × 10−11 cm2) supported formation of a 20-μm thick platelet layer, which unexpectedly underwent massive platelet retraction upon flow arrest. This contraction resulted in a 5.34-fold increase in permeability due to collagen restructuring. Without stopping flow, platelet deposits (no fibrin) had a permeability of κplatelet = 5.45 × 10−14 cm2 and platelet-fibrin thrombi had κthrombus = 2.71 × 10−14 cm2 for ΔP = 20.7 to 23.4 mm-Hg, the first ever measurements for clots formed under arterial flow (1130 s−1 wall shear rate). Platelet sensing of flow cessation triggered a 4.6 to 6.5-fold (n=3, P<0.05) increase in contraction rate, which was also observed in a rigid, impermeable parallel-plate microfluidic device. This triggered contraction was blocked by the myosin IIA inhibitor blebbistatin and by inhibitors of thromboxane (TXA2) and ADP signaling. In addition, flow arrest triggered platelet intracellular calcium mobilization, which was blocked by TXA2/ADP inhibitors. As clots become occlusive or vessels rupture, flow around developed clots diminishes facilitating full platelet retraction and hemostasis. Conclusion Flow dilution of ADP and thromboxane regulates platelet contractility with prevailing hemodynamics, a newly defined flow sensing mechanism to regulate clot function. PMID:23087356

Development of Lateral Flow Immunochromatographic Strips for Micropollutants Screening Using Colorants of Aptamer Functionalized Nanogold Particles Part I: Methodology and Optimization.

PubMed

Zhao, Shuai; Zhang, Shan; Wang, Sai; Liu, Jiahui; Dong, Yiyang

2018-05-03

A methodology of lateral flow immunochromatographic strip based on aptamer was developed for on-site detectionof the small molecule micropollutants. In the present study, we try for the first time to investigate the feasibility of developing a strip assay for the analysis of micropollutants as methodological prototypes by combining the high selectivity and affinity of aptamers with the unique optical properties of nanogolds. This quantitative method was based on the competition for the aptamer between targets and DNA probes. Crucial parameters that might influence the sensitivity, such as the size of nanogolds, amount of aptamer, type and pH of streptavidin, type of nitrocellulose (NC) membrane, blocking procedure, and reading time, were systematically investigated to obtain the optimum assay performance. With the optimized conditions [nanogolds 25 nm, 50 μM aptamer, pH 8 of GSA (a type of streptavidin named "SA Gold," which is a sulfhydrylization streptavidin), Millipore HFC 135 NC membrane, 1% bovine serum albumin as the blocking agent and added in the running buffer and sample pad soakage agents, and 20 min reading time] the aptamer-based lateral flow assay will show a low visual limit of detection and scanning reader LOD. The strip for on-site screening using colorants of aptamer functionalized nanogold particles did not require any complicated equipment and was a potential portable tool for rapid identification of micropollutants.

Ontogeny of flow-stimulated potassium secretion in rabbit cortical collecting duct: functional and molecular aspects.

PubMed

Woda, Craig B; Miyawaki, Nobuyuki; Ramalakshmi, Santhanam; Ramkumar, Mohan; Rojas, Raul; Zavilowitz, Beth; Kleyman, Thomas R; Satlin, Lisa M

2003-10-01

High urinary flow rates stimulate K secretion in the fully differentiated but not neonatal or weanling rabbit cortical collecting duct (CCD). Both small-conductance secretory K and high-conductance Ca2+/stretch-activated maxi-K channels have been identified in the apical membrane of the mature CCD by patch-clamp analysis. We reported that flow-stimulated net K secretion in the adult rabbit CCD is 1) blocked by TEA and charybdotoxin, inhibitors of intermediate- and high-conductance (maxi-K) Ca2+-activated K channels, and 2) associated with increases in net Na absorption and intracellular Ca2+ concentration ([Ca2+]i). The present study examined whether the absence of flow-stimulated K secretion early in life is due to a 1) limited flow-induced rise in net Na absorption and/or [Ca2+]i and/or 2) paucity of apical maxi-K channels. An approximately sixfold increase in tubular fluid flow rate in CCDs isolated from 4-wk-old rabbits and microperfused in vitro led to an increase in net Na absorption and [Ca2+]i, similar in magnitude to the response observed in 6-wk-old tubules, but it failed to generate an increase in net K secretion. By 5 wk of age, there was a small, but significant, flow-stimulated rise in net K secretion that increased further by 6 wk of life. Luminal perfusion with iberiotoxin blocked the flow stimulation of net K secretion in the adult CCD, confirming the identity of the maxi-K channel in this response. Maxi-K channel alpha-subunit message was consistently detected in single CCDs from animals >/=4 wk of age by RT-PCR. Indirect immunofluorescence microscopy using antibodies directed against the alpha-subunit revealed apical labeling of intercalated cells in cryosections from animals >/=5 wk of age; principal cell labeling was generally intracellular and punctate. We speculate that the postnatal appearance of flow-dependent K secretion is determined by the transcriptional/translational regulation of expression of maxi-K channels. Furthermore, our studies suggest a novel function for intercalated cells in mediating flow-stimulated K secretion.

Pre-test CFD Calculations for a Bypass Flow Standard Problem

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

Rich Johnson

The bypass flow in a prismatic high temperature gas-cooled reactor (HTGR) is the flow that occurs between adjacent graphite blocks. Gaps exist between blocks due to variances in their manufacture and installation and because of the expansion and shrinkage of the blocks from heating and irradiation. Although the temperature of fuel compacts and graphite is sensitive to the presence of bypass flow, there is great uncertainty in the level and effects of the bypass flow. The Next Generation Nuclear Plant (NGNP) program at the Idaho National Laboratory has undertaken to produce experimental data of isothermal bypass flow between three adjacentmore » graphite blocks. These data are intended to provide validation for computational fluid dynamic (CFD) analyses of the bypass flow. Such validation data sets are called Standard Problems in the nuclear safety analysis field. Details of the experimental apparatus as well as several pre-test calculations of the bypass flow are provided. Pre-test calculations are useful in examining the nature of the flow and to see if there are any problems associated with the flow and its measurement. The apparatus is designed to be able to provide three different gap widths in the vertical direction (the direction of the normal coolant flow) and two gap widths in the horizontal direction. It is expected that the vertical bypass flow will range from laminar to transitional to turbulent flow for the different gap widths that will be available.« less

Mantle heat flow and thermal structure of the northern block of Southern Granulite Terrain, India

NASA Astrophysics Data System (ADS)

Manglik, Ajay

2006-07-01

Continental shield regions are normally characterized by low-to-moderate mantle heat flow. Archaean Dharwar craton of the Indian continental shield also follows the similar global pattern. However, some recent studies have inferred significantly higher mantle heat flow for the Proterozoic northern block of Southern Granulite Terrain (SGT) in the immediate vicinity of the Dharwar craton by assuming that the radiogenic elements depleted exposed granulites constitute the 45-km-thick crust. In this study, we use four-layered model of the crustal structure revealed by integrated geophysical studies along a geo-transect in this region to estimate the mantle heat flow. The results indicate that: (i) the mantle heat flow of the northern block of SGT is 17 ± 2 mW/m 2, supporting the global pattern, and (ii) the lateral variability of 10-12 mW/m 2 in the surface heat flow within the block is of crustal origin. In terms of temperature, the Moho beneath the eastern Salem-Namakkal region appears to be at 80-100 °C higher temperature than that beneath the western Avinashi region.

Amphiphilic block copolymer membrane for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Wang, Fei; Sylvia, James M.; Jacob, Monsy M.; Peramunage, Dharmasena

2013-11-01

An amphiphilic block copolymer comprised of hydrophobic polyaryletherketone (PAEK) and hydrophilic sulfonated polyaryletherketone (SPAEK) blocks has been synthesized and characterized. A membrane prepared from the block copolymer is used as the separator in a single cell vanadium redox flow battery (VRB). The proton conductivity, mechanical property, VO2+ permeability and single VRB cell performance of this block copolymer membrane are investigated and compared to Nafion™ 117. The block copolymer membrane showed significantly improved vanadium ion selectivity, higher mechanical strength and lower conductivity than Nafion™ 117. The VRB containing the block copolymer membrane exhibits higher coulombic efficiency and similar energy efficiency compared to a VRB using Nafion™ 117. The better vanadium ion selectivity of the block copolymer membrane has led to a much smaller capacity loss during 50 charge-discharge cycles for the VRB.

Hydraulic transport across hydrophilic and hydrophobic nanopores: Flow experiments with water and n-hexane.

PubMed

Gruener, Simon; Wallacher, Dirk; Greulich, Stefanie; Busch, Mark; Huber, Patrick

2016-01-01

We experimentally explore pressure-driven flow of water and n-hexane across nanoporous silica (Vycor glass monoliths with 7- or 10-nm pore diameters, respectively) as a function of temperature and surface functionalization (native and silanized glass surfaces). Hydraulic flow rates are measured by applying hydrostatic pressures via inert gases (argon and helium, pressurized up to 70 bar) on the upstream side in a capacitor-based membrane permeability setup. For the native, hydrophilic silica walls, the measured hydraulic permeabilities can be quantitatively accounted for by bulk fluidity provided we assume a sticking boundary layer, i.e., a negative velocity slip length of molecular dimensions. The thickness of this boundary layer is discussed with regard to previous capillarity-driven flow experiments (spontaneous imbibition) and with regard to velocity slippage at the pore walls resulting from dissolved gas. Water flow across the silanized, hydrophobic nanopores is blocked up to a hydrostatic pressure of at least 70 bar. The absence of a sticking boundary layer quantitatively accounts for an enhanced n-hexane permeability in the hydrophobic compared to the hydrophilic nanopores.

Ice/water slurry blocking phenomenon at a tube orifice.

PubMed

Hirochi, Takero; Yamada, Shuichi; Shintate, Tuyoshi; Shirakashi, Masataka

2002-10-01

The phenomenon of ice-particle/water mixture blocking flow through a pipeline is a problem that needs to be solved before mixture flow can be applied for practical use in cold energy transportation in a district cooling system. In this work, the blocking mechanism of ice-particle slurry at a tube orifice is investigated and a criterion for blocking is presented. The cohesive nature of ice particles is shown to cause compressed plug type blocking and the compressive yield stress of a particle cluster is presented as a measure for the cohesion strength of ice particles.

Low-leakage and low-instability labyrinth seal

NASA Technical Reports Server (NTRS)

Rhode, David L. (Inventor)

1997-01-01

Improved labyrinth seal designs are disclosed. The present invention relates to labyrinth seal systems with selected sealing surfaces and seal geometry to optimize flow deflection and produce maximum turbulent action. Optimum seal performance is generally accomplished by providing sealing surfaces and fluid cavities formed to dissipate fluid energy as a function of the geometry of the sealing surfaces along with the position and size of the fluid cavities formed between members of the labyrinth seal system. Improved convex surfaces, annular flow reversal grooves, flow deflection blocks and rough, machined surfaces cooperate to enhance the performance of the labyrinth seal systems. For some labyrinth seal systems a mid-cavity throttle and either rigid teeth or flexible spring teeth may be included.

Blocking Mechanism Study of Self-Compacting Concrete Based on Discrete Element Method

NASA Astrophysics Data System (ADS)

Zhang, Xuan; Li, Zhida; Zhang, Zhihua

2017-11-01

In order to study the influence factors of blocking mechanism of Self-Compaction Concrete (SCC), Roussel’s granular blocking model was verified and extended by establishing the discrete element model of SCC. The influence of different parameters on the filling capacity and blocking mechanism of SCC were also investigated. The results showed that: it was feasible to simulate the blocking mechanism of SCC by using Discrete Element Method (DEM). The passing ability of pebble aggregate was superior to the gravel aggregate and the passing ability of hexahedron particles was bigger than tetrahedron particles, while the tetrahedron particle simulation results were closer to the actual situation. The flow of SCC as another significant factor affected the passing ability that with the flow increased, the passing ability increased. The correction coefficient λ of the steel arrangement (channel section shape) and flow rate γ in the block model were introduced that the value of λ was 0.90-0.95 and the maximum casting rate was 7.8 L/min.

Be together, not the same: Spatiotemporal organization of different cilia types generates distinct transport functions

NASA Astrophysics Data System (ADS)

Nawroth, Janna; Guo, Hanliang; Ruby, Edward; Dabiri, John; McFall-Ngai, Margaret; Kanso, Eva

2016-11-01

Motile cilia are microscopic, hair-like structures on the cell surface that can sense and propel the extracellular fluid environment. Cilia are often thought to be limited to stereotypic morphologies, beat kinematics and non-discriminatory clearance functions, but we find that the spatiotemporal organization of different cilia types and beat behaviors can generate complex flow patterns and transport functions. Here, we present a case study in the Hawaiian bobtail squid where collective ciliary activity and resulting flow fields help recruit symbiont bacteria to the animal host. In particular, we demonstrate empirically and computationally how the squid's internal cilia act like a microfluidic device that actively filters the water for potential bacterial candidates and also provides a sheltered zone allowing for accumulation of mucus and bacteria into a biofilm. Moreover, in this sheltered zone, different cilia-driven flows enhance diffusion of biochemical signals, which could accelerate specific bacteria-host recognition. These results suggest that studying cilia activity on the population level might reveal a diverse range of biological transport and sensing functions. Moreover, understanding cilia as functional building blocks could inspire the design of ciliated robots and devices.

Synthesis of α-amino-1,3-dicarbonyl compounds via Ugi flow chemistry reaction: access to functionalized 1,2,3-triazoles.

PubMed

Vasconcelos, Stanley N S; Fornari, Evelin; Caracelli, Ignez; Stefani, Hélio A

2017-11-01

The Ugi multicomponent reaction has been used as an important synthetic route to obtain compounds with potential biological activity. We present the rapid and efficient synthesis of [Formula: see text]-amino-1,3-dicarbonyl compounds in moderate to good yields via Ugi flow chemistry reactions performed with a continuous flow reactor. Such [Formula: see text]-amino-1,3-dicarbonyl compounds can act as precursors for the production of [Formula: see text]-amino acids via hydrolysis of the ethyl ester group as well as building blocks for the synthesis of novel compounds with the 1,2,3-triazole ring. The [Formula: see text]-amino acid derivatives of the Ugi flow chemistry reaction products were then used for dipeptide synthesis.

A direct method for the solution of unsteady two-dimensional incompressible Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Ghia, K. N.; Osswald, G. A.; Ghia, U.

1983-01-01

The unsteady incompressible Navier-Stokes equations are formulated in terms of vorticity and stream function in generalized curvilinear orthogonal coordinates to facilitiate analysis of flow configurations with general geometries. The numerical method developed solves the conservative form of the transport equation using the alternating-direction implicit method, whereas the stream-function equation is solved by direct block Gaussian elimination. The method is applied to a model problem of flow over a back-step in a doubly infinite channel, using clustered conformal coordinates. One-dimensional stretching functions, dependent on the Reynolds number and the asymptotic behavior of the flow, are used to provide suitable grid distribution in the separation and reattachment regions, as well as in the inflow and outflow regions. The optimum grid distribution selected attempts to honor the multiple length scales of the separated-flow model problem. The asymptotic behavior of the finite-differenced transport equation near infinity is examined and the numerical method is carefully developed so as to lead to spatially second-order accurate wiggle-free solutions, i.e., with minimum dispersive error. Results have been obtained in the entire laminar range for the backstep channel and are in good agreement with the available experimental data for this flow problem.

Shuttle payload interface verification equipment study. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1976-01-01

A preliminary design analysis of a stand alone payload integration device (IVE) is provided that is capable of verifying payload compatibility in form, fit and function with the shuttle orbiter prior to on-line payload/orbiter operations. The IVE is a high fidelity replica of the orbiter payload accommodations capable of supporting payload functional checkout and mission simulation. A top level payload integration analysis developed detailed functional flow block diagrams of the payload integration process for the broad spectrum of P/L's and identified degree of orbiter data required by the payload user and potential applications of the IVE.

On-orbit flight control algorithm description

NASA Technical Reports Server (NTRS)

1975-01-01

Algorithms are presented for rotational and translational control of the space shuttle orbiter in the orbital mission phases, which are external tank separation, orbit insertion, on-orbit and de-orbit. The program provides a versatile control system structure while maintaining uniform communications with other programs, sensors, and control effectors by using an executive routine/functional subroutine format. Software functional requirements are described using block diagrams where feasible, and input--output tables, and the software implementation of each function is presented in equations and structured flow charts. Included are a glossary of all symbols used to define the requirements, and an appendix of supportive material.

Adaptive 3D single-block grids for the computation of viscous flows around wings

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

Hagmeijer, R.; Kok, J.C.

1996-12-31

A robust algorithm for the adaption of a 3D single-block structured grid suitable for the computation of viscous flows around a wing is presented and demonstrated by application to the ONERA M6 wing. The effects of grid adaption on the flow solution and accuracy improvements is analyzed. Reynolds number variations are studied.

Effects of forearm bier block with bretylium on the hemodynamic and metabolic responses to handgrip

NASA Technical Reports Server (NTRS)

Lee, F.; Shoemaker, J. K.; McQuillan, P. M.; Kunselman, A. R.; Smith, M. B.; Yang, Q. X.; Smith, H.; Gray, K.; Sinoway, L. I.

2000-01-01

We tested the hypothesis that a reduction in sympathetic tone to exercising forearm muscle would increase blood flow, reduce muscle acidosis, and attenuate reflex responses. Subjects performed a progressive, four-stage rhythmic handgrip protocol before and after forearm bier block with bretylium as forearm blood flow (Doppler) and metabolic (venous effluent metabolite concentration and (31)P-NMR indexes) and autonomic reflex responses (heart rate, blood pressure, and sympathetic nerve traffic) were measured. Bretylium inhibits the release of norepinephrine at the neurovascular junction. Bier block increased blood flow as well as oxygen consumption in the exercising forearm (P < 0.03 and P < 0.02, respectively). However, despite this increase in flow, venous K(+) release and H(+) release were both increased during exercise (P < 0.002 for both indexes). Additionally, minimal muscle pH measured during the first minute of recovery with NMR was lower after bier block (6.41 +/- 0.08 vs. 6.20 +/- 0.06; P < 0.036, simple effects). Meanwhile, reflex effects were unaffected by the bretylium bier block. The results support the conclusion that sympathetic stimulation to muscle during exercise not only limits muscle blood flow but also appears to limit anaerobiosis and H(+) release, presumably through a preferential recruitment of oxidative fibers.

CALUTRON

DOEpatents

Lawrence, E.O.; Brobeck, W.M.

1959-04-14

ABS>An ion source is described for a calutron especially designed to improve the uniformity of charge vapor flow when the vapor encounters the arc. The inventive feature of the source consists of a specific source block construction wherein heater means prevents condensation from taking place within the block, and a separate vapor generator is supported on the wall of the block by a hollow thimble. The thimble communicates with a bore cavity in the block and the vapor flows therethrough into the cavity and uniformly out a slot along the length of the cavity where the arc discharge is located.

Two coarse pyroclastic flow deposits, northern Mono-Inyo Craters, CA

NASA Astrophysics Data System (ADS)

Dennen, R. L.; Bursik, M. I.; Stokes, P. J.; Lagamba, M.; Fontanella, N.; Hintz, A. R.; Jayko, A. S.

2010-12-01

The ~1350 A.D., rhyolitic North Mono eruption, Mono-Inyo Craters, CA, included the extrusion and destruction of Panum Dome and associated clastic deposits. Overlying the tephras of the North Mono sequence, the Panum deposits include a block-and-ash flow (BAF) deposit, covering ~3.5 km2. Blocks within the deposit are typically lithic rhyolite and banded gray micro-vesicular glass, showing white, almost powdery marks ranging from circular to linear in shape. These marks are interpreted as friction marks resulting from collisions between clasts. The deposit also contains bread-crusted obsidians with pressed-in clasts as well as reticulite with a bread-crusted surface texture. Near the centerline of the deposit is a ridge-topping train of jigsaw fractured blocks, often with reddish-orange alteration. One house sized jigsaw block sits upstream of a long, thinning pile of reddish orange debris; this “flow shadow” indicates that the block remained relatively stationary while the block and ash flow continued to propagate around it. The bread-crusted reticulite is most common at proximal localities. It is proposed that the dome destruction included a debris avalanche emplacing the train of jigsaw fractured blocks and creating a topographic high, the block-and-ash flow (the farthest reaching deposit from this event) which flowed around the debris avalanche deposits, and a final “lateral expansion” of a magma foam, creating the reticulite seen concentrated at proximal locations. Another coarse pyroclastic flow (here termed the “lower blast deposit”) underlies the North Mono tephra. It is more obsidian rich and finer grained than the Panum BAF. The lower blast deposit may have originated from Pumice Pit vent, which is now capped with an older dome ~0.5 km southeast of Panum. The lower blast deposit extends farther from the Panum vent than does the Panum BAF deposit, and apparently was mistaken for the Panum BAF deposit by previous workers. Hence the run-out distance of the Panum BAF is smaller than previously reported. Thus, there are multiple, coarse pyroclastic flow-like deposits at the northern end of the Mono-Inyo Craters, reflecting multiple phases of dome destruction. The lower blast deposit is proposed to be a blast event predating the Panum eruption, possibly originating from Pumice Pit. The Panum BAF consists of three main facies, formed by three separate, sequential events. A debris avalanche deposited a train of jigsaw clasts along a narrow path, followed by a block and ash flow that spread material over a wider region. Finally, molten rhyolite was exposed by the earlier events, resulting in rapid foam expansion and creation of a bread crusted reticulite-bearing facies.

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.

A block-based algorithm for the solution of compressible flows in rotor-stator combinations

NASA Technical Reports Server (NTRS)

Akay, H. U.; Ecer, A.; Beskok, A.

1990-01-01

A block-based solution algorithm is developed for the solution of compressible flows in rotor-stator combinations. The method allows concurrent solution of multiple solution blocks in parallel machines. It also allows a time averaged interaction at the stator-rotor interfaces. Numerical results are presented to illustrate the performance of the algorithm. The effect of the interaction between the stator and rotor is evaluated.

Effective Light Directed Assembly of Building Blocks with Microscale Control.

PubMed

Dinh, Ngoc-Duy; Luo, Rongcong; Christine, Maria Tankeh Asuncion; Lin, Weikang Nicholas; Shih, Wei-Chuan; Goh, James Cho-Hong; Chen, Chia-Hung

2017-06-01

Light-directed forces have been widely used to pattern micro/nanoscale objects with precise control, forming functional assemblies. However, a substantial laser intensity is required to generate sufficient optical gradient forces to move a small object in a certain direction, causing limited throughput for applications. A high-throughput light-directed assembly is demonstrated as a printing technology by introducing gold nanorods to induce thermal convection flows that move microparticles (diameter = 40 µm to several hundreds of micrometers) to specific light-guided locations, forming desired patterns. With the advantage of effective light-directed assembly, the microfluidic-fabricated monodispersed biocompatible microparticles are used as building blocks to construct a structured assembly (≈10 cm scale) in ≈2 min. The control with microscale precision is approached by changing the size of the laser light spot. After crosslinking assembly of building blocks, a novel soft material with wanted pattern is approached. To demonstrate its application, the mesenchymal stem-cell-seeded hydrogel microparticles are prepared as functional building blocks to construct scaffold-free tissues with desired structures. This light-directed fabrication method can be applied to integrate different building units, enabling the bottom-up formation of materials with precise control over their internal structure for bioprinting, tissue engineering, and advanced manufacturing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of channel blocking on information transmission and energy efficiency in squid giant axons.

PubMed

Liu, Yujiang; Yue, Yuan; Yu, Yuguo; Liu, Liwei; Yu, Lianchun

2018-04-01

Action potentials are the information carriers of neural systems. The generation of action potentials involves the cooperative opening and closing of sodium and potassium channels. This process is metabolically expensive because the ions flowing through open channels need to be restored to maintain concentration gradients of these ions. Toxins like tetraethylammonium can block working ion channels, thus affecting the function and energy cost of neurons. In this paper, by computer simulation of the Hodgkin-Huxley neuron model, we studied the effects of channel blocking with toxins on the information transmission and energy efficiency in squid giant axons. We found that gradually blocking sodium channels will sequentially maximize the information transmission and energy efficiency of the axons, whereas moderate blocking of potassium channels will have little impact on the information transmission and will decrease the energy efficiency. Heavy blocking of potassium channels will cause self-sustained oscillation of membrane potentials. Simultaneously blocking sodium and potassium channels with the same ratio increases both information transmission and energy efficiency. Our results are in line with previous studies suggesting that information processing capacity and energy efficiency can be maximized by regulating the number of active ion channels, and this indicates a viable avenue for future experimentation.

Crustal deformation mechanism in southeastern Tibetan Plateau: Insights from numerical modeling

NASA Astrophysics Data System (ADS)

Li, Y.; Liu, S.; Chen, L.

2017-12-01

The Indo-Asian collision developed the complicated crustal deformation around the southeastern Tibetan plateau. Numerous models have proposed to explain the crustal deformation, but the mechanism remains controversial, especially the increasing multi-geophysics data, which demonstrate the existence of lower velocity, lower resistivity and high conductivity, implying that lower crustal flow is responsible for the crustal deformation, arguing for the lower crust flow model. To address the relations between the crust flow and the surface deformation, we employ a three-dimensional viscoelastic finite model to investigate the possible influence on the surface deformation, and discuss the stress field distribution under the model. Our preliminary results suggest that lower crustal flow plays an important role in crustal deformation in southeastern Tibetan plateau. The best fitting is achieved when the flow velocity of the lower crust is approximately 10-11 mm/a faster than that of the upper crust. Crustal rheological properties affect regional crustal deformation, when the viscosity of the middle and lower crust in the South China block reaches 1022 and 1023 Pa.s, respectively; the predicted match observations well, especially for the magnitude within the South China block. The maximum principal stress field exhibits clear zoning, gradually shifting from an approximately east-west orientation in the northern Bayan Har block to southeast in the South China block, southwest in the western Yunnan block, and a radially divergent distribution in the Middle Yunnan and Southern Yunnan blocks.

Key Topics for High-Lift Research: A Joint Wind Tunnel/Flight Test Approach

NASA Technical Reports Server (NTRS)

Fisher, David; Thomas, Flint O.; Nelson, Robert C.

1996-01-01

Future high-lift systems must achieve improved aerodynamic performance with simpler designs that involve fewer elements and reduced maintenance costs. To expeditiously achieve this, reliable CFD design tools are required. The development of useful CFD-based design tools for high lift systems requires increased attention to unresolved flow physics issues. The complex flow field over any multi-element airfoil may be broken down into certain generic component flows which are termed high-lift building block flows. In this report a broad spectrum of key flow field physics issues relevant to the design of improved high lift systems are considered. It is demonstrated that in-flight experiments utilizing the NASA Dryden Flight Test Fixture (which is essentially an instrumented ventral fin) carried on an F-15B support aircraft can provide a novel and cost effective method by which both Reynolds and Mach number effects associated with specific high lift building block flows can be investigated. These in-flight high lift building block flow experiments are most effective when performed in conjunction with coordinated ground based wind tunnel experiments in low speed facilities. For illustrative purposes three specific examples of in-flight high lift building block flow experiments capable of yielding a high payoff are described. The report concludes with a description of a joint wind tunnel/flight test approach to high lift aerodynamics research.

Slope-scale dynamic states of rockfalls

NASA Astrophysics Data System (ADS)

Agliardi, F.; Crosta, G. B.

2009-04-01

Rockfalls are common earth surface phenomena characterised by complex dynamics at the slope scale, depending on local block kinematics and slope geometry. We investigated the nature of this slope-scale dynamics by parametric 3D numerical modelling of rockfalls over synthetic slopes with different inclination, roughness and spatial resolution. Simulations were performed through an original code specifically designed for rockfall modeling, incorporating kinematic and hybrid algorithms with different damping functions available to model local energy loss by impact and pure rolling. Modelling results in terms of average velocity profiles suggest that three dynamic regimes (i.e. decelerating, steady-state and accelerating), previously recognized in the literature through laboratory experiments on granular flows, can set up at the slope scale depending on slope average inclination and roughness. Sharp changes in rock fall kinematics, including motion type and lateral dispersion of trajectories, are associated to the transition among different regimes. Associated threshold conditions, portrayed in "phase diagrams" as slope-roughness critical lines, were analysed depending on block size, impact/rebound angles, velocity and energy, and model spatial resolution. Motion in regime B (i.e. steady state) is governed by a slope-scale "viscous friction" with average velocity linearly related to the sine of slope inclination. This suggest an analogy between rockfall motion in regime B and newtonian flow, whereas in regime C (i.e. accelerating) an analogy with a dilatant flow was observed. Thus, although local behavior of single falling blocks is well described by rigid body dynamics, the slope scale dynamics of rockfalls seem to statistically approach that of granular media. Possible outcomes of these findings include a discussion of the transition from rockfall to granular flow, the evaluation of the reliability of predictive models, and the implementation of criteria for a preliminary evaluation of hazard assessment and countermeasure planning.

Numerical Upscaling of Solute Transport in Fractured Porous Media Based on Flow Aligned Blocks

NASA Astrophysics Data System (ADS)

Leube, P.; Nowak, W.; Sanchez-Vila, X.

2013-12-01

High-contrast or fractured-porous media (FPM) pose one of the largest unresolved challenges for simulating large hydrogeological systems. The high contrast in advective transport between fast conduits and low-permeability rock matrix, including complex mass transfer processes, leads to the typical complex characteristics of early bulk arrivals and long tailings. Adequate direct representation of FPM requires enormous numerical resolutions. For large scales, e.g. the catchment scale, and when allowing for uncertainty in the fracture network architecture or in matrix properties, computational costs quickly reach an intractable level. In such cases, multi-scale simulation techniques have become useful tools. They allow decreasing the complexity of models by aggregating and transferring their parameters to coarser scales and so drastically reduce the computational costs. However, these advantages come at a loss of detail and accuracy. In this work, we develop and test a new multi-scale or upscaled modeling approach based on block upscaling. The novelty is that individual blocks are defined by and aligned with the local flow coordinates. We choose a multi-rate mass transfer (MRMT) model to represent the remaining sub-block non-Fickian behavior within these blocks on the coarse scale. To make the scale transition simple and to save computational costs, we capture sub-block features by temporal moments (TM) of block-wise particle arrival times to be matched with the MRMT model. By predicting spatial mass distributions of injected tracers in a synthetic test scenario, our coarse-scale solution matches reasonably well with the corresponding fine-scale reference solution. For predicting higher TM-orders (such as arrival time and effective dispersion), the prediction accuracy steadily decreases. This is compensated to some extent by the MRMT model. If the MRMT model becomes too complex, it loses its effect. We also found that prediction accuracy is sensitive to the choice of the effective dispersion coefficients and on the block resolution. A key advantage of the flow-aligned blocks is that the small-scale velocity field is reproduced quite accurately on the block-scale through their flow alignment. Thus, the block-scale transverse dispersivities remain in the similar magnitude as local ones, and they do not have to represent macroscopic uncertainty. Also, the flow-aligned blocks minimize numerical dispersion when solving the large-scale transport problem.

VALVE

DOEpatents

Arkelyan, A.M.; Rickard, C.L.

1962-04-17

A gate valve for controlling the flow of fluid in separate concentric ducts or channels by means of a single valve is described. In one position, the valve sealing discs engage opposed sets of concentric ducts leading to the concentric pipes defining the flow channels to block flow therethrough. In another position, the discs are withdrawn from engagement with the opposed ducts and at the same time a bridging section is interposed therebetween to define concentric paths coextensive with and connecting the opposed ducts to facilitate flow therebetween. A wedge block arrangement is employed with each sealing disc to enable it to engage the ducts. The wedge block arrangement also facilitates unobstructcd withdrawal of the discs out of the intervening space between the sets of ducts. (AEC)

Architecture and design of a 500-MHz gallium-arsenide processing element for a parallel supercomputer

NASA Technical Reports Server (NTRS)

Fouts, Douglas J.; Butner, Steven E.

1991-01-01

The design of the processing element of GASP, a GaAs supercomputer with a 500-MHz instruction issue rate and 1-GHz subsystem clocks, is presented. The novel, functionally modular, block data flow architecture of GASP is described. The architecture and design of a GASP processing element is then presented. The processing element (PE) is implemented in a hybrid semiconductor module with 152 custom GaAs ICs of eight different types. The effects of the implementation technology on both the system-level architecture and the PE design are discussed. SPICE simulations indicate that parts of the PE are capable of being clocked at 1 GHz, while the rest of the PE uses a 500-MHz clock. The architecture utilizes data flow techniques at a program block level, which allows efficient execution of parallel programs while maintaining reasonably good performance on sequential programs. A simulation study of the architecture indicates that an instruction execution rate of over 30,000 MIPS can be attained with 65 PEs.

The Study of Blocking Agent on Lengkeng (Euphoria Logan Lour) Fruit Shell and Seed for Adsorption of Pb (II) from Aqueous Solution

NASA Astrophysics Data System (ADS)

Kurniawati, D.; Zein, R.; Chaidir, Z.; Aziz, H.

2018-04-01

The study focuses on the roles played by mayor functional groups(carboxyl) in the lengkeng shell for sorption of Pb (II). The biosorbent was characterized by FTIR and elemental analyses. The parameters such as pH, initial concentration, particle sizes, adsorbent dose and flow rate were also studied. The results showed that the optimum condition was at pH = 3, concentration 400 mg/l, 250 μm particle sizes, adsorbent dose 0,5 g and 2 ml/min flow rate with adsorption capacity 4,8933 mg/g(shell) and 5,2720 mg/g(seed). It is show that ion exchange play as a more important role in the sorption of Pb (II) on lengkeng shell and seed. Blocking of COOH groups by chemical esterification resulted in Pb important reduction in metal binding.The result showed that adsorption capacity of lengkeng shell uncreases until 63.67 % and lengkeng seed uncreases 98.70%.

Dynamic Characteristics of Regional Flows around the Pyrénées in View of the PYREX Experiment. Part I: Analysis of the Pressure and Wind Fields and Experimental Assessment of the Applicability of the Linear Theory.

NASA Astrophysics Data System (ADS)

Bénech, B.; Koffi, E.; Druilhet, A.; Durand, P.; Bessemoulin, P.; Campins, J.; Jansa, A.; Terliuc, B.

1998-01-01

regarding (a) the perturbation of the surface pressure field, which resembles the predicted bipolar distribution; (b) the dependence of the drag on Fr1, which enables the assessment of the linear theory and the definition of the conditions of applicability of two models [(i) a two-dimensional model, for which it was possible to define quantitatively the effective blocked area, and (ii) a three-dimensional model, for which a scaling function that combines the direction of incidence, the mountain shape, and the Coriolis effect was found almost constant, with an average value of 0.2 for all the cases under study]; (c) the extension of the area affected by the blocking effect, estimated to be 4.5-5 times the width of the barrier and the drift of the strong deceleration point due to the Coriolis effect; (d) the dependence of the wind velocities on Fr1 at the edges of the barrier; and (e) the asymmetric flow deviation induced by the Coriolis effect and biased by the departure of the flow from normal incidence.

Combining CFD simulations with blockoriented heatflow-network model for prediction of photovoltaic energy-production

NASA Astrophysics Data System (ADS)

Haber, I. E.; Farkas, I.

2011-01-01

The exterior factors which influencing the working circumstances of photovoltaic modules are the irradiation, the optical air layer (Air Mass - AM), the irradiation angle, the environmental temperature and the cooling effect of the wind. The efficiency of photovoltaic (PV) devices is inversely proportional to the cell temperature and therefore the mounting of the PV modules can have a big affect on the cooling, due to wind flow-around and naturally convection. The construction of the modules could be described by a heatflow-network model, and that can define the equation which determines the cells temperature. An equation like this can be solved as a block oriented model with hybrid-analogue simulator such as Matlab-Simulink. In view of the flow field and the heat transfer, witch was calculated numerically, the heat transfer coefficients can be determined. Five inflow rates were set up for both pitched and flat roof cases, to let the trend of the heat transfer coefficient know, while these functions can be used for the Matlab/Simulink model. To model the free convection flows, the Boussinesq-approximation were used, integrated into the Navier-Stokes equations and the energy equation. It has been found that under a constant solar heat gain, the air velocity around the modules and behind the pitched-roof mounted module is increasing, proportionately to the wind velocities, and as result the heat transfer coefficient increases linearly, and can be described by a function in both cases. To the block based model the meteorological parameters and the results of the CFD simulations as single functions were attached. The final aim was to make a model that could be used for planning photovoltaic systems, and define their accurate performance for better sizing of an array of modules.

Cavitation erosion in blocked flow with a ducted ice-class propeller

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

Doucet, J.M.; Bose, N.; Walker, D.

1996-12-31

Ships that operate in ice often encounter momentary increased propeller cavitation because ice pieces block the flow into the propeller. For ducted propellers, this additional cavitation is more significant than it is for open propellers; ice pieces may become lodged against and within the duct and subject the propeller to longer periods of increased cavitation due to the blocked flow. Associated with this blocked flow is the possibility of cavitation erosion on the propeller. An erosion study, using paint films, was conducted in a cavitation tunnel with a model propeller of the type fitted to the Canadian Marine Drilling Ltd.more » vessel MV Robert LeMeur. A simulated ice blockage was installed ahead of the propeller model and within the duct. Tests were carried out over a range of advance coefficients for various test conditions. The resulting types of cavitation were documented, the erosion patterns were photographed and comparisons between each test were made.« less

Quantifying mountain block recharge by means of catchment-scale storage-discharge relationships

NASA Astrophysics Data System (ADS)

Ajami, Hoori; Troch, Peter A.; Maddock, Thomas, III; Meixner, Thomas; Eastoe, Chris

2011-04-01

Despite the importance of mountainous catchments for providing freshwater resources, especially in semi-arid regions, little is known about key hydrological processes such as mountain block recharge (MBR). Here we implement a data-based method informed by isotopic data to quantify MBR rates using recession flow analysis. We applied our hybrid method in a semi-arid sky island catchment in southern Arizona, United States. Sabino Creek is a 91 km2 catchment with its sources near the summit of the Santa Catalina Mountains northeast of Tucson. Southern Arizona's climate has two distinct wet seasons separated by prolonged dry periods. Winter frontal storms (November-March) provide about 50% of annual precipitation, and summers are dominated by monsoon convective storms from July to September. Isotope analyses of springs and surface water in the Sabino Creek catchment indicate that streamflow during dry periods is derived from groundwater storage in fractured bedrock. Storage-discharge relationships are derived from recession flow analysis to estimate changes in storage during wet periods. To provide reliable estimates, several corrections and improvements to classic base flow recession analysis are considered. These corrections and improvements include adaptive time stepping, data binning, and the choice of storage-discharge functions. Our analysis shows that (1) incorporating adaptive time steps to correct for streamflow measurement errors improves the coefficient of determination, (2) the quantile method is best for streamflow data binning, (3) the choice of the regression model is critical when the stage-discharge function is used to predict changes in bedrock storage beyond the maximum observed flow in the catchment, and (4) the use of daily or night-time hourly streamflow does not affect the form of the storage-discharge relationship but will impact MBR estimates because of differences in the observed range of streamflow in each series.

Arp2/3 complex–dependent actin networks constrain myosin II function in driving retrograde actin flow

PubMed Central

Yang, Qing; Zhang, Xiao-Feng; Pollard, Thomas D.

2012-01-01

The Arp2/3 complex nucleates actin filaments to generate networks at the leading edge of motile cells. Nonmuscle myosin II produces contractile forces involved in driving actin network translocation. We inhibited the Arp2/3 complex and/or myosin II with small molecules to investigate their respective functions in neuronal growth cone actin dynamics. Inhibition of the Arp2/3 complex with CK666 reduced barbed end actin assembly site density at the leading edge, disrupted actin veils, and resulted in veil retraction. Strikingly, retrograde actin flow rates increased with Arp2/3 complex inhibition; however, when myosin II activity was blocked, Arp2/3 complex inhibition now resulted in slowing of retrograde actin flow and veils no longer retracted. Retrograde flow rate increases induced by Arp2/3 complex inhibition were independent of Rho kinase activity. These results provide evidence that, although the Arp2/3 complex and myosin II are spatially segregated, actin networks assembled by the Arp2/3 complex can restrict myosin II–dependent contractility with consequent effects on growth cone motility. PMID:22711700

Static internal performance of ventral and rear nozzle concepts for short-takeoff and vertical-landing aircraft

NASA Technical Reports Server (NTRS)

Re, Richard J.; Carson, George T., Jr.

1991-01-01

The internal performance of two exhaust system concepts applicable to single-engine short-take-off and vertical-landing tactical fighter configurations was investigated. These concepts involved blocking (or partially blocking) tailpipe flow to the rear (cruise) nozzle and diverting it through an opening to a ventral nozzle exit for vertical thrust. A set of variable angle vanes at the ventral nozzle exit were used to vary ventral nozzle thrust angle between 45 and 110 deg relative to the positive axial force direction. In the vertical flight mode the rear nozzle (or tailpipe flow to it) was completely blocked. In the transition flight mode flow in the tailpipe was split between the rear and ventral nozzles and the flow was vectored at both exits for aircraft control purposes through this flight regime. In the cruise flight mode the ventral nozzle was sealed and all flow exited through the rear nozzle.

Flow dynamics analyses of pathophysiological liver lobules using porous media theory

NASA Astrophysics Data System (ADS)

Hu, Jinrong; Lü, Shouqin; Feng, Shiliang; Long, Mian

2017-08-01

Blood flow inside the liver plays a key role in hepatic functions, and abnormal hemodynamics are highly correlated with liver diseases. To date, the flow field in an elementary building block of the organ, the liver lobule, is difficult to determine experimentally in humans due to its complicated structure, with radially branched microvasculature and the technical difficulties that derive from its geometric constraints. Here we established a set of 3D computational models for a liver lobule using porous media theory and analyzed its flow dynamics in normal, fibrotic, and cirrhotic lobules. Our simulations indicated that those approximations of ordinary flow in portal tracts (PTs) and the central vein, and of porous media flow in the sinusoidal network, were reasonable only for normal or fibrotic lobules. Models modified with high resistance in PTs and collateral vessels inside sinusoids were able to describe the flow features in cirrhotic lobules. Pressures, average velocities, and volume flow rates were profiled and the predictions compared well with experimental data. This study furthered our understanding of the flow dynamics features of liver lobules and the differences among normal, fibrotic, and cirrhotic lobules.

Joint Inversion for Lithospheric Structures: Implications for the Growth and Deformation in Northeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Deng, Yangfan; Li, Jiangtao; Song, Xiaodong; Zhu, Lupei

2018-05-01

Several geodynamic models have been proposed for the deformation mechanism of Tibetan Plateau (TP), but it remains controversial. Here we applied a method of joint inversion of receiver functions and surface wave dispersions with P wave velocity constraint to a dense linear array in the NE Tibet. The results show that the geological blocks, separated by major faults at the surface, are characterized by distinct features in the crust, the Moho, and the uppermost mantle. The main features include crustal low-velocity zones (LVZs) with variable strengths, anomalous Vp/Vs ratios that are correlated with LVZs, a large Moho jump, and other abrupt changes near major faults, strong mantle lithosphere anomalies, and correlation of crustal and mantle velocities. The results suggest a lithospheric-scale deformation of continuous shortening as well as localized faulting, which is affected by the strength of the lithosphere blocks. The thickened mantle lithosphere can be removed, which facilitates the formation of middle-lower crustal LVZ and flow. However, such flow is likely a consequence of the deformation rather than a driving force for the outward growth of the TP. The proposed model of TP deformation and growth can reconcile the continuous deformation within the blocks and major faults at the surface.

The effects of catecholamines and adrenoceptor blocking drugs on the canine peripheral lymph flow.

PubMed Central

De Micheli, P; Glässer, A H

1975-01-01

Blood flow through the femoral artery, lymph flow in a lymphatic vessel in the femoral triangle and metatarsal distal venous pressure were measured simultaneously in a canine moving hind limb. 2. Low intra-arterial doses of adrenaline and noradrenaline increased lymph flow even in the presence of marked arterial vasoconstriction. In contrast, isoprenaline increased arterial blood flow without affecting lymph flow rate. 3. Phenoxybenzamine, dihydroergotoxine, and nicergoline did not inhibit the lymphatic flow increase induced by adrenaline at doses active on arterial or venous vascular alpha-adrenoceptors. 4. Propranolol given intra-arterially into animals pretreated with alpha-adrenoceptor blocking agents restored the vasoconstrictor effect of adrenaline (reversal of adrenaline reversal). PMID:238702

Nuées ardentes of 22 November 1994 at Merapi volcano, Java, Indonesia

USGS Publications Warehouse

Abdurachman, E.K.; Bourdier, J.-L.; Voight, B.

2000-01-01

Nuées ardentes associated with dome collapse on 22 November 1994, at Merapi volcano traveled to the south–southwest as far as 6.5 km, and collectively accumulated roughly 2.5–3 million cubic meters of deposits. The damaged area comprises 9.5 km2 and is covered by two nuée ardente facies, a conventional “Merapi-type”, valley-fill block-and-ash flow facies and a pyroclastic surge facies. The proximal deposits reflect the accumulation of dozens of nuées ardentes, with many subsidiary flow units. The distal deposits are more simply organized, as only a few individual events reached to distances >3.5 km. The stratigraphic relationships north of Turgo hill indicate that the surge deposits are a facies of particularly mobile nuées ardentes that also deposited channeled block-and-ash flow facies. They further suggest that the surge facies beyond the channel margins correlate laterally with a finer-grained sublayer locally developed at the base of the block-and-ash flow facies. Eyewitness reports suggest that the emplacement of the block-and-ash flow facies in the distal part of the Boyong river may have followed, by a short time interval, the destruction and deposition of the surge facies at Turgo village. The stratigraphy is in accord with the eyewitness reports. The surge facies was emplaced by a dilute surge current, detached from the same dome-collapse nuée ardente that, as a separate flow unit, subsequently emplaced the distal block-and-ash deposit in the Boyong valley. The detachment occurred at higher elevations, likely at or above the slope break at about 2000 m elevation. This flow separation enabled the surge current to shortcut over the landscape and to emplace its deposit even as the block-and-ash flow continued its tortuous southward movement in the Boyong channel. Dome-collapse nuée ardente activity formed the bulk of the eruption, which was accompanied by virtually no significant vertical summit explosive activity.

Pyroclastic Flow (Post-)Emplacement Thermal History Derived From Titanomagnetite Curie Temperatures: Mt. St. Helens and Soufrière Hills as Test Cases

NASA Astrophysics Data System (ADS)

Bowles, J.; Jackson, M.; Lappe, S. C. L. L.; Solheid, P.; Stinton, A. J.

2014-12-01

Pumice blocks and ash matrix sampled from the 1980 pyroclastic flows at Mt. St. Helens and the 2010 flow at Soufrière Hills, Montserrat, display magnetic Curie temperatures (TC) that vary strongly with depth in the flow. We demonstrate that these TC variations result from variable degrees of cation ordering within Mg- and Al-bearing titanomagnetites, and that the degree of ordering is dependent on the emplacement temperature and post-emplacement thermal history of the sample. Curie temperatures are lowest at the tops of flows where rapid cooling has quenched in a relatively low degree of cation order. Samples that cooled more slowly at depth in the flow evolved towards a higher degree of cation order with a correspondingly higher TC. Isothermal annealing experiments in the laboratory have allowed us to document the time-temperature evolution of the cation ordering and Curie temperature, and we use this data in combination with conductive cooling calculations to forward model stratigraphic variations in TC as a function of emplacement temperature (e.g., Fig.1). Preliminary results show that modeled emplacement temperatures (Templ) are reasonably close to measured or estimated emplacement temperatures. Thermal demagnetization data from lithic clasts incorporated into some flows supports the modeled emplacement temperatures; a low-temperature overprint in the direction of the present-day field is removed at ~Templ. However, the documented variation of TC with thermal history means that care should be taken in interpreting this more traditional lithic-based paleomagnetic paleothermometry data. Modification of Curie and blocking temperatures both during natural cooling and during laboratory thermal treatments could affect lithic-based emplacement temperature estimates.

Comparison of Flow and Volume Incentive Spirometry on Pulmonary Function and Exercise Tolerance in Open Abdominal Surgery: A Randomized Clinical Trial.

PubMed

Kumar, Amaravadi Sampath; Alaparthi, Gopala Krishna; Augustine, Alfred Joseph; Pazhyaottayil, Zulfeequer Chundaanveetil; Ramakrishna, Anand; Krishnakumar, Shyam Krishnan

2016-01-01

Surgical procedures in abdominal area lead to changes in pulmonary function, respiratory mechanics and impaired physical capacity leading to postoperative pulmonary complications, which can affect up to 80% of upper abdominal surgery. To evaluate the effects of flow and volume incentive spirometry on pulmonary function and exercise tolerance in patients undergoing open abdominal surgery. A randomized clinical trial was conducted in a hospital of Mangalore city in Southern India. Thirty-seven males and thirteen females who were undergoing abdominal surgeries were included and allocated into flow and volume incentive spirometry groups by block randomization. All subjects underwent evaluations of pulmonary function with measurement of Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Peak Expiratory Flow (PEF). Preoperative and postoperative measurements were taken up to day 5 for both groups. Exercise tolerance measured by Six- Minute Walk Test during preoperative period and measured again at the time of discharge for both groups. Pulmonary function was analysed by post-hoc analysis and carried out using Bonferroni's 't'-test. Exercise tolerance was analysed by Paired 'T'-test. Pulmonary function (FVC, FEV1, and PEFR) was found to be significantly decreased in 1(st), 2(nd) and 3(rd) postoperative day when compared with preoperative day. On 4(th) and 5(th) postoperative day the pulmonary function (FVC, FEV1, and PEFR) was found to be better preserved in both flow and volume incentive spirometry groups. The Six-Minute Walk Test showed a statistically significant improvement in pulmonary function on the day of discharge than in the preoperative period. In terms of distance covered, the volume- incentive spirometry group showed a greater statistically significant improvement from the preoperative period to the time of discharge than was exhibited by the flow incentive spirometry group. Flow and volume incentive spirometry can be safely recommended to patients undergoing open abdominal surgery as there have been no adverse events recorded. Also, these led to a demonstrable improvement in pulmonary function and exercise tolerance.

Comparison of Flow and Volume Incentive Spirometry on Pulmonary Function and Exercise Tolerance in Open Abdominal Surgery: A Randomized Clinical Trial

PubMed Central

Kumar, Amaravadi Sampath; Augustine, Alfred Joseph; Pazhyaottayil, Zulfeequer Chundaanveetil; Ramakrishna, Anand; Krishnakumar, Shyam Krishnan

2016-01-01

Introduction Surgical procedures in abdominal area lead to changes in pulmonary function, respiratory mechanics and impaired physical capacity leading to postoperative pulmonary complications, which can affect up to 80% of upper abdominal surgery. Aim To evaluate the effects of flow and volume incentive spirometry on pulmonary function and exercise tolerance in patients undergoing open abdominal surgery. Materials and Methods A randomized clinical trial was conducted in a hospital of Mangalore city in Southern India. Thirty-seven males and thirteen females who were undergoing abdominal surgeries were included and allocated into flow and volume incentive spirometry groups by block randomization. All subjects underwent evaluations of pulmonary function with measurement of Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Peak Expiratory Flow (PEF). Preoperative and postoperative measurements were taken up to day 5 for both groups. Exercise tolerance measured by Six- Minute Walk Test during preoperative period and measured again at the time of discharge for both groups. Pulmonary function was analysed by post-hoc analysis and carried out using Bonferroni’s ‘t’-test. Exercise tolerance was analysed by Paired ‘T’-test. Results Pulmonary function (FVC, FEV1, and PEFR) was found to be significantly decreased in 1st, 2nd and 3rd postoperative day when compared with preoperative day. On 4th and 5th postoperative day the pulmonary function (FVC, FEV1, and PEFR) was found to be better preserved in both flow and volume incentive spirometry groups. The Six-Minute Walk Test showed a statistically significant improvement in pulmonary function on the day of discharge than in the preoperative period. In terms of distance covered, the volume- incentive spirometry group showed a greater statistically significant improvement from the preoperative period to the time of discharge than was exhibited by the flow incentive spirometry group. Conclusion Flow and volume incentive spirometry can be safely recommended to patients undergoing open abdominal surgery as there have been no adverse events recorded. Also, these led to a demonstrable improvement in pulmonary function and exercise tolerance. PMID:26894090

Revisit submergence of ice blocks in front of ice cover—an experimental study

NASA Astrophysics Data System (ADS)

Wang, Jun; Wu, Yi-fan; Sui, Jueyi

2018-04-01

The present paper studies the stabilities of ice blocks in front of an ice cover based on experiments carried out in laboratory by using four types of ice blocks with different dimensions. The forces acting on the ice blocks in front of the ice cover are analyzed. The critical criteria for the entrainment of ice blocks in front of the ice cover are established by considering the drag force caused by the flowing water, the collision force, and the hydraulic pressure force. Formula for determining whether or not an ice block will be entrained under the ice cover is derived. All three dimensions of the ice block are considered in the proposed formula. The velocities calculated by using the developed formula are compared with those of calculated by other formulas proposed by other researchers, as well as the measured flow velocities for the entrainment of ice blocks in laboratory. The fitting values obtained by using the derived formula agree well with the experimental results.

Cerebroprotective functions of HO-2.

PubMed

Parfenova, Helena; Leffler, Charles W

2008-01-01

The constitutive isoform of heme oxygenase, HO-2, is highly expressed in the brain and in cerebral vessels. HO-2 functions in the brain have been evaluated using pharmacological inhibitors of the enzyme and HO-2 gene deletion in in vivo animal models and in cultured cells (neurons, astrocytes, cerebral vascular endothelial cells). Rapid activation of HO-2 via post-translational modifications without upregulation of HO-2 expression or HO-1 induction coincides with the increase in cerebral blood flow aimed at maintaining brain homeostasis and neuronal survival during seizures, hypoxia, and hypotension. Pharmacological inhibition or gene deletion of brain HO-2 exacerbates oxidative stress induced by seizures, glutamate, and inflammatory cytokines, and causes cerebral vascular injury. Carbon monoxide (CO) and bilirubin, the end products of HO-catalyzed heme degradation, have distinct cytoprotective functions. CO, by binding to a heme prosthetic group, regulates the key components of cell signaling, including BK(Ca) channels, guanylyl cyclase, NADPH oxidase, and the mitochondria respiratory chain. Cerebral vasodilator effects of CO are mediated via activation of BK(Ca) channels and guanylyl cyclase. CO, by inhibiting the major components of endogenous oxidant-generating machinery, NADPH oxidase and the cytochrome C oxidase of the mitochondrial respiratory chain, blocks formation of reactive oxygen species. Bilirubin, via redox cycling with biliverdin, is a potent oxidant scavenger that removes preformed oxidants. Overall, HO-2 has dual housekeeping cerebroprotective functions by maintaining autoregulation of cerebral blood flow aimed at improving neuronal survival in a changing environment, and by providing an effective defense mechanism that blocks oxidant formation and prevents cell death caused by oxidative stress.

ESOC - The satellite operation center of the European Space Agency

NASA Astrophysics Data System (ADS)

Dworak, H. P.

1980-04-01

The operation and individual functions of the European Space Operation Center (ESOC) that controls the flight of ESA satellites are presented. The main role of the ESOC is discussed and its division into three areas: telemetry, remote piloting, and tracking is outlined. Attention is given to the manipulation of experimental data collected on board the satellites as well as to the functions of the individual ground stations. A block diagram of the information flow to the Meteosat receiving station is presented along with the network outlay of data flow between the ground stations and the ESOC. Distribution of tasks between the ground operation manager, spacecraft operations manager, and flight dynamic software coordinator is discussed with reference to a mission team. A short description of the current missions including COS-B, GEOS-1 and 2, Meteosat, OTS, and ISEE-B is presented

How to use your peak flow meter

MedlinePlus

Peak flow meter - how to use; Asthma - peak flow meter; Reactive airway disease - peak flow meter; Bronchial asthma - peak flow meter ... your airways are narrowed and blocked due to asthma, your peak flow values drop. You can check ...

Detecting dominant motion patterns in crowds of pedestrians

NASA Astrophysics Data System (ADS)

Saqib, Muhammad; Khan, Sultan Daud; Blumenstein, Michael

2017-02-01

As the population of the world increases, urbanization generates crowding situations which poses challenges to public safety and security. Manual analysis of crowded situations is a tedious job and usually prone to errors. In this paper, we propose a novel technique of crowd analysis, the aim of which is to detect different dominant motion patterns in real-time videos. A motion field is generated by computing the dense optical flow. The motion field is then divided into blocks. For each block, we adopt an Intra-clustering algorithm for detecting different flows within the block. Later on, we employ Inter-clustering for clustering the flow vectors among different blocks. We evaluate the performance of our approach on different real-time videos. The experimental results show that our proposed method is capable of detecting distinct motion patterns in crowded videos. Moreover, our algorithm outperforms state-of-the-art methods.

Laurentide glacial landscapes: the role of ice streams

USGS Publications Warehouse

Patterson, C.J.

1998-01-01

Glacial landforms of the North American prairie can be divided into two suites that result from different styles of ice flow: 1) a lowland suite of level-to-streamlined till consistent with formation beneath ice streams, and 2) an upland and lobe-margin suite of thick, hummocky till and glacial thrust blocks consistent with formation at ice-stream and ice-lobe margins. Southern Laurentide ice lobes hypothetically functioned as outlets of ice streams. Broad branching lowlands bounded by escarpments mark the stable positions of the ice streams that fed the lobes. If the lobes and ice streams were similar to modern ice streams, their fast flow was facilitated by high subglacial water pressure. Favorable geology and topography in the midcontinent encouraged nonuniform ice flow and controlled the location of ice streams and outlet lobes.

Finite element computation of a viscous compressible free shear flow governed by the time dependent Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Cooke, C. H.; Blanchard, D. K.

1975-01-01

A finite element algorithm for solution of fluid flow problems characterized by the two-dimensional compressible Navier-Stokes equations was developed. The program is intended for viscous compressible high speed flow; hence, primitive variables are utilized. The physical solution was approximated by trial functions which at a fixed time are piecewise cubic on triangular elements. The Galerkin technique was employed to determine the finite-element model equations. A leapfrog time integration is used for marching asymptotically from initial to steady state, with iterated integrals evaluated by numerical quadratures. The nonsymmetric linear systems of equations governing time transition from step-to-step are solved using a rather economical block iterative triangular decomposition scheme. The concept was applied to the numerical computation of a free shear flow. Numerical results of the finite-element method are in excellent agreement with those obtained from a finite difference solution of the same problem.

Gp120/CD4 blocking antibodies are frequently elicited in ART-naïve chronically HIV-1 infected individuals.

PubMed

Carrillo, Jorge; Molinos-Albert, Luis Manuel; Rodríguez de la Concepción, Maria Luisa; Marfil, Silvia; García, Elisabet; Derking, Ronald; Sanders, Rogier W; Clotet, Bonaventura; Blanco, Julià

2015-01-01

Antibodies with the ability to block the interaction of HIV-1 envelope glycoprotein (Env) gp120 with CD4, including those overlapping the CD4 binding site (CD4bs antibodies), can protect from infection by HIV-1, and their elicitation may be an interesting goal for any vaccination strategy. To identify gp120/CD4 blocking antibodies in plasma samples from HIV-1 infected individuals we have developed a competitive flow cytometry-based functional assay. In a cohort of treatment-naïve chronically infected patients, we showed that gp120/CD4 blocking antibodies were frequently elicited (detected in 97% plasma samples) and correlated with binding to trimeric HIV-1 envelope glycoproteins. However, no correlation was observed between functional CD4 binding blockade data and titer of CD4bs antibodies determined by ELISA using resurfaced gp120 proteins. Consistently, plasma samples lacking CD4bs antibodies were able to block the interaction between gp120 and its receptor, indicating that antibodies recognizing other epitopes, such as PGT126 and PG16, can also play the same role. Antibodies blocking CD4 binding increased over time and correlated positively with the capacity of plasma samples to neutralize the laboratory-adapted NL4.3 and BaL virus isolates, suggesting their potential contribution to the neutralizing workforce of plasma in vivo. Determining whether this response can be boosted to achieve broadly neutralizing antibodies may provide valuable information for the design of new strategies aimed to improve the anti-HIV-1 humoral response and to develop a successful HIV-1 vaccine.

Gp120/CD4 Blocking Antibodies Are Frequently Elicited in ART-Naïve Chronically HIV-1 Infected Individuals

PubMed Central

Carrillo, Jorge; Molinos-Albert, Luis Manuel; de la Concepción, Maria Luisa Rodríguez; Marfil, Silvia; García, Elisabet; Derking, Ronald; Sanders, Rogier W.; Clotet, Bonaventura; Blanco, Julià

2015-01-01

Antibodies with the ability to block the interaction of HIV-1 envelope glycoprotein (Env) gp120 with CD4, including those overlapping the CD4 binding site (CD4bs antibodies), can protect from infection by HIV-1, and their elicitation may be an interesting goal for any vaccination strategy. To identify gp120/CD4 blocking antibodies in plasma samples from HIV-1 infected individuals we have developed a competitive flow cytometry-based functional assay. In a cohort of treatment-naïve chronically infected patients, we showed that gp120/CD4 blocking antibodies were frequently elicited (detected in 97% plasma samples) and correlated with binding to trimeric HIV-1 envelope glycoproteins. However, no correlation was observed between functional CD4 binding blockade data and titer of CD4bs antibodies determined by ELISA using resurfaced gp120 proteins. Consistently, plasma samples lacking CD4bs antibodies were able to block the interaction between gp120 and its receptor, indicating that antibodies recognizing other epitopes, such as PGT126 and PG16, can also play the same role. Antibodies blocking CD4 binding increased over time and correlated positively with the capacity of plasma samples to neutralize the laboratory-adapted NL4.3 and BaL virus isolates, suggesting their potential contribution to the neutralizing workforce of plasma in vivo. Determining whether this response can be boosted to achieve broadly neutralizing antibodies may provide valuable information for the design of new strategies aimed to improve the anti-HIV-1 humoral response and to develop a successful HIV-1 vaccine. PMID:25803681

Long-term exposure to diesel engine exhaust induced lung function decline in a cross sectional study

PubMed Central

ZHANG, Li Ping; ZHANG, Xiao; DUAN, Hua Wei; MENG, Tao; NIU, Yong; HUANG, Chuan Feng; GAO, Wei Min; YU, Shan Fa; ZHENG, Yu Xin

2016-01-01

To clarify the effects of lung function following exposure to diesel engine exhaust (DEE), we recruited 137 diesel engine testing workers exposed to DEE and 127 non-DEE-exposed workers as study subjects. We performed lung function tests and measured cytokinesis-block micronucleus (CBMN) cytome index and levels of urinary polycyclic aromatic hydrocarbons (PAHs) metabolites. There was a significant decrease of forced expiratory volume in 1 second (FEV1), ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/ FVC), maximal mid expiratory flow curve (MMF), forced expiratory flow at 50% of FVC (FEF50%), and forced expiratory flow at 75% of FVC (FEF75%) in the DEE-exposed workers than non-DEE-exposed workers (all p<0.05). Among all study subjects, the decreases of FEF75% were associated with the increasing levels of PAHs metabolites (p<0.05), and there were negative correlations between FEV1, FEV1/FVC, MMF, FEF50%, and FEF75% with CBMN cytome index (all p<0.05). Our results show that long-term exposure to DEE can induce lung function decline which shows mainly obstructive changes and influence of small airways function. The decreased lung function is associated with internal dosage of DEE exposure, and accompany with the increasing CBMN cytome index. PMID:27334424

Using noble gas tracers to constrain a groundwater flow model with recharge elevations: A novel approach for mountainous terrain

USGS Publications Warehouse

Doyle, Jessica M.; Gleeson, Tom; Manning, Andrew H.; Mayer, K. Ulrich

2015-01-01

Environmental tracers provide information on groundwater age, recharge conditions, and flow processes which can be helpful for evaluating groundwater sustainability and vulnerability. Dissolved noble gas data have proven particularly useful in mountainous terrain because they can be used to determine recharge elevation. However, tracer-derived recharge elevations have not been utilized as calibration targets for numerical groundwater flow models. Herein, we constrain and calibrate a regional groundwater flow model with noble-gas-derived recharge elevations for the first time. Tritium and noble gas tracer results improved the site conceptual model by identifying a previously uncertain contribution of mountain block recharge from the Coast Mountains to an alluvial coastal aquifer in humid southwestern British Columbia. The revised conceptual model was integrated into a three-dimensional numerical groundwater flow model and calibrated to hydraulic head data in addition to recharge elevations estimated from noble gas recharge temperatures. Recharge elevations proved to be imperative for constraining hydraulic conductivity, recharge location, and bedrock geometry, and thus minimizing model nonuniqueness. Results indicate that 45% of recharge to the aquifer is mountain block recharge. A similar match between measured and modeled heads was achieved in a second numerical model that excludes the mountain block (no mountain block recharge), demonstrating that hydraulic head data alone are incapable of quantifying mountain block recharge. This result has significant implications for understanding and managing source water protection in recharge areas, potential effects of climate change, the overall water budget, and ultimately ensuring groundwater sustainability.

Bypass Flow Resistance in Prismatic Gas-Cooled Nuclear Reactors

DOE PAGES

McEligot, Donald M.; Johnson, Richard W.

2016-12-20

Available computational fluid dynamics (CFD) predictions of pressure distributions in the vertical bypass flow between blocks in a prismatic gas-cooled reactor (GCR) have been analyzed to deduce apparent friction factors and loss coefficients for systems and network codes. We performed calculations for vertical gap spacings "s" of 2, 6 and 10 mm, horizontal gaps between the blocks of two mm and two flow rates, giving a range of gap Reynolds numbers Re Dh of about 40 to 5300. Laminar predictions of the fully-developed friction factor f fd were about three to ten per cent lower than the classical infinitely-wide channelmore » In the entry region, the local apparent friction factor was slightly higher than the classic idealized case but the hydraulic entry length L hy was approximately the same. The per cent reduction in flow resistance was greater than the per cent increase in flow area at the vertical corners of the blocks. The standard k-ϵ model was employed for flows expected to be turbulent. Its predictions of f fd and flow resistance were significantly higher than direct numerical simulations for the classic case; the value of L hy was about thirty gap spacings. Initial quantitative information for entry coefficients and loss coefficients for the expansion-contraction junctions between blocks is also presented. Our study demonstrates how CFD predictions can be employed to provide integral quantities needed in systems and network codes.« less

Bypass Flow Resistance in Prismatic Gas-Cooled Nuclear Reactors

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

McEligot, Donald M.; Johnson, Richard W.

Available computational fluid dynamics (CFD) predictions of pressure distributions in the vertical bypass flow between blocks in a prismatic gas-cooled reactor (GCR) have been analyzed to deduce apparent friction factors and loss coefficients for systems and network codes. We performed calculations for vertical gap spacings "s" of 2, 6 and 10 mm, horizontal gaps between the blocks of two mm and two flow rates, giving a range of gap Reynolds numbers Re Dh of about 40 to 5300. Laminar predictions of the fully-developed friction factor f fd were about three to ten per cent lower than the classical infinitely-wide channelmore » In the entry region, the local apparent friction factor was slightly higher than the classic idealized case but the hydraulic entry length L hy was approximately the same. The per cent reduction in flow resistance was greater than the per cent increase in flow area at the vertical corners of the blocks. The standard k-ϵ model was employed for flows expected to be turbulent. Its predictions of f fd and flow resistance were significantly higher than direct numerical simulations for the classic case; the value of L hy was about thirty gap spacings. Initial quantitative information for entry coefficients and loss coefficients for the expansion-contraction junctions between blocks is also presented. Our study demonstrates how CFD predictions can be employed to provide integral quantities needed in systems and network codes.« less

Multi-port valve assembly

DOEpatents

Guggenheim, S. Frederic

1986-01-01

A multi-port fluid valve apparatus is used to control the flow of fluids through a plurality of valves and includes a web, which preferably is a stainless steel endless belt. The belt has an aperture therethrough and is progressed, under motor drive and control, so that its aperture is moved from one valve mechanism to another. Each of the valve mechanisms comprises a pair of valve blocks which are held in fluid-tight relationship against the belt. Each valve block consists of a block having a bore through which the fluid flows, a first seal surrounding the bore and a second seal surrounding the first seal, with the distance between the first and second seals being greater than the size of the belt aperture. In order to open a valve, the motor progresses the belt aperture to where it is aligned with the two bores of a pair of valve blocks, such alignment permitting a flow of the fluid through the valve. The valve is closed by movement of the belt aperture and its replacement, within the pair of valve blocks, by a solid portion of the belt.

Improved 3-D turbomachinery CFD algorithm

NASA Technical Reports Server (NTRS)

Janus, J. Mark; Whitfield, David L.

1988-01-01

The building blocks of a computer algorithm developed for the time-accurate flow analysis of rotating machines are described. The flow model is a finite volume method utilizing a high resolution approximate Riemann solver for interface flux definitions. This block LU implicit numerical scheme possesses apparent unconditional stability. Multi-block composite gridding is used to orderly partition the field into a specified arrangement. Block interfaces, including dynamic interfaces, are treated such as to mimic interior block communication. Special attention is given to the reduction of in-core memory requirements by placing the burden on secondary storage media. Broad applicability is implied, although the results presented are restricted to that of an even blade count configuration. Several other configurations are presently under investigation, the results of which will appear in subsequent publications.

Dose-response studies of Ropivacaine in blood flow of upper extremity after supraclavicular block: a double-blind randomized controlled study.

PubMed

Li, Ting; Ye, Qiguang; Wu, Daozhu; Li, Jun; Yu, Jingui

2017-12-02

The sympathetic block of upper limb leading to increased blood flow has important clinical implication in microvascular surgery. However, little is known regarding the relationship between concentration of local anesthetic and blood flow of upper limb. The aim of this dose-response study was to determine the ED 50 and ED 95 of ropivacaine in blood flow after supraclavicular block (SB). Patients undergoing upper limb surgery and supraclavicular block were randomly assigned to receive 30ml ropivacaine in concentrations of 0.125%(A Group), 0.2%(B Group), 0.25%(C Group), 0.375%(D Group), 0.5%(E Group), or 0.75%(F Group) (n=13 per group). All patients received supraclavicular block (SB). Time average maximum velocity (TAMAX), cross-sectional area (CSA) of brachial artery and skin temperatures (T s ) were measured repeatedly at the same marked points, they were taken at baseline (before block, t 0 ) and at 30min after SB (t 1 ). Blood flow(BF) = TAMAX× CSA×60 sec.. Relative blood flow (ΔBF) = BF t1 / BF t0 . Success of SB was assessed simultaneously. Supplementary anesthesia and other adverse events (AE) were recorded. Significant increase in TAMAX, CSA, BF and T s were seen in all concentration groups at t 1 comparing with t 0 (P<0.001). There was an upward trend of TAMAX, CSA, BF with the increasing concentration of ropivacaine except T s . There was no significant different of T s at t 1 among different concentration group. The dose-response formula of ropivacaine on ΔBF was Y=1+3.188/(1+10^((-2.451-X) × 1.730)) and ED 50 /ED 95 (95%CI) were 0.35/1.94%(0.25-0.45/0.83-4.52), and R 2 (coefficient of determination) =0.85. ED 50 /ED 95 (95%CI) values of sensory block were 0.18/0.33% (0.15-0.21/0.27-0.51), R 2 =0.904. The dose-response curve between SB ropivacaine and the changes of BF was determined. The ED 50 /ED 95 of ropivacaine of ΔBF are 0.35/1.94% (0.25-0.45/0.83-4.52). TAMAX, CSA and BF consistently increased with ropivacaine concentration. The maximal sympathetic block needs higher concentration than that complete sensation block needs which may benefit for microvascular surgery. Clinicaltrials.gov NCT02139982 . Retrospectively registered (Date of registration: May, 2014).

Analysis of the 2006 block-and-ash flow deposits of Merapi Volcano, Java, Indonesia, using high-spatial resolution IKONOS images and complementary ground based observations

NASA Astrophysics Data System (ADS)

Thouret, Jean-Claude; Gupta, Avijit; Liew, Soo Chin; Lube, Gert; Cronin, Shane J.; Surono, Dr

2010-05-01

On 16 June 2006 an overpass of IKONOS coincided with the emplacement of an active block-and-ash flow fed by a lava dome collapse event at Merapi Volcano (Java, Indonesia). This was the first satellite image recorded for a moving pyroclastic flow. The very high-spatial resolution data displayed the extent and impact of the pyroclastic deposits emplaced during and prior to, the day of image acquisition. This allowed a number of features associated with high-hazard block-and-ash flows emplaced in narrow, deep gorges to be mapped, interpreted and understood. The block-and-ash flow and surge deposits recognized in the Ikonos images include: (1) several channel-confined flow lobes and tongues in the box-shaped valley; (2) thin ash-cloud surge deposit and knocked-down trees in constricted areas on both slopes of the gorge; (3) fan-like over bank deposits on the Gendol-Tlogo interfluves from which flows were re-routed in the Tlogo secondary valley; (4) massive over bank lobes on the right bank from which flows devastated the village of Kaliadem 0.5 km from the main channel, a small part of this flow being re-channeled in the Opak secondary valley. The high-resolution IKONOS images also helped us to identify geomorphic obstacles that enabled flows to ramp and spill out from the sinuous channel, a process called flow avulsion. Importantly, the avulsion redirected flows to unexpected areas away from the main channel. In the case of Merapi we see that the presence of valley fill by previous deposits, bends and man-made dams influence the otherwise valley-guided course of the flows. Sadly, Sabo dams (built to ameliorate the effect of high sediment load streams) can actually cause block-and-ash flows to jump out of their containing channel and advance into sensitive areas. Very-high-spatial resolution satellite images are very useful for mapping and interpreting the distribution of freshly erupted volcanic deposits. IKONOS-type images with 1-m resolution provide opportunities to study and map the meter-scale detail of volcanic deposits. When such high-spatial-resolution satellite remote sensing data are combined with in situ field work, geomorphic analyses can be applied that allow us to more fully understand the dynamics and hazards of eruptions. In the case given here, IKONOS imagery allowed two qualitative hazard assessments for block-and-ash flow activity in drainages around Merapi. Firstly, the interpretation of IKONOS images provides insights in factors that control the propagation of secondary flows as the avulsion of the main flows is driven by longitudinal change in channel capacity due to increased sinuosity in the valley and decreased containment space. Secondly, the sinuosity and obstacles (including Sabo dams) may create over bank flows over adjacent low relief, allowing them to reach unexpectedly vulnerable areas distant from an active dome and away from the volcanically active valleys. Hazard assessment should therefore consider the geometry of secondary channels outside the principal valleys.

RADON FUNDAMENTALS AND THE EFFECTIVENESS OF COATINGS IN REDUCING SOIL GAS FLOW THROUGH BLOCK BASEMENT WALLS

EPA Science Inventory

The paper gives results of an evaluation of six different coatings in specially designed chambers built around 1.5 sq m concrete block wall sections. Data were collected over a pressure range of 1-12 Pa with flows from < 0.01 to 50 standard liters/minute (SLPM). The six coatings ...

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.

Cancer Cell Glycocalyx Mediates Mechanostransduction and Flow-Regulated Invasion

PubMed Central

Qazi, Henry; Palomino, Rocio; Shi, Zhong-Dong; Munn, Lance L.; Tarbell, John M.

2014-01-01

Mammalian cells are covered by a surface proteoglycan (glycocalyx) layer, and it is known that blood vessel-lining endothelial cells use the glycocalyx to sense and transduce the shearing forces of blood flow into intracellular signals. Tumor cells in vivo are exposed to forces from interstitial fluid flow that may affect metastatic potential but are not reproduced by most in vitro cell motility assays. We hypothesized that glycocalyx-mediated mechanotransduction of interstitial flow shear stress is an un-recognized factor that can significantly enhance metastatic cell motility and play a role in augmentation of invasion. Involvement of MMP levels, cell adhesion molecules (CD44, α3 integrin), and glycocalyx components (heparan sulfate and hyaluronan) were investigated in a cell/collagen gel suspension model designed to mimic the interstitial flow microenvironment. Physiologic levels of flow upregulated MMP levels and enhanced the motility of metastatic cells. Blocking the flow-enhanced expression of MMP actvity or adhesion molecules (CD44 and integrins) resulted in blocking the flow-enhanced migratory activity. The presence of a glycocalyx-like layer was verified around tumor cells, and the degradation of this layer by hyaluronidase and heparinase blocked the flow-regulated invasion. This study shows for the first time that interstitial flow enhancement of metastatic cell motility can be mediated by the cell surface glycocalyx – a potential target for therapeutics. PMID:24077103

Geological-morphological description of the Ishtar Terra (photomap of the Venusian surface sheet B-5)

NASA Technical Reports Server (NTRS)

Sukhanov, A. L.; Pronin, A. A.; Tyuflin, Y. S.; Ostrovskiy, M. V.; Kotelnikov, V. A.; Rzhiga, O. N.; Petrov, G. I.; Sidorenko, A. I.; Aleksandrov, Y. N.; Zakharov, A. I.

1986-01-01

The main part of the Ishtar Terra east of the Maxwell Montes is covered with systems of areal dislocations of several directions, which are called Parquet. According to the structural patterns these may be divided into: (1) the central stable block; (2) the lesser peripheral blocks separated from the central one by gaps and grabens; (3) the zones of mobilized parquet, whose substance flowed downward at an incline in the directions away from the central block in the form of plastic flows; and (4) the partially parqueted lava sheets. The Maxwell Montes were formed as a result of the collision between the central parquet block and the Lakshmi Planum.

Heterogeneities in Myocardial Flow and Metabolism: Exacerbation with Abnormal Excitation

PubMed Central

Bassingthwaighte, James B.; Li, Zheng

2010-01-01

Because regional myocardial blood flows are remarkably heterogeneous—with a 6- to 10-fold range of flows in normal hearts—and because the spatial profiles of the flows are stable over long periods and over a range of conditions, the relation between flows and other physiologic functions has been explored. Local fatty acid uptake and oxygen consumption are almost linearly related to the flows. Coronary network structure and hydrodynamic resistances give suitable flow heterogeneity but are thought to be a response to local needs rather than being causative. Presumably the cause is the need for adenosine triphosphate (ATP) synthesis locally, and therefore flows, substrate delivery, and oxygen utilization are driven primarily by local rates of ATP hydrolysis, mainly by contractile proteins. This hypothesis is by no means fully tested. Data on pacing dog hearts from different sites, on patients with left bundle branch block, and on unloading transplanted rat hearts, all point in the same direction: unloading ventricular muscle leads to diminished flow and exaggeratedly diminished glucose uptake. The mechanism is likely to be that discovered by Taegtmeyer and colleagues, namely, the expression of fetal genes in regions where the muscle is unloaded and particular metabolic enzymes and transporters are downregulated. PMID:10750580

Auto covariance computer

NASA Technical Reports Server (NTRS)

Hepner, T. E.; Meyers, J. F. (Inventor)

1985-01-01

A laser velocimeter covariance processor which calculates the auto covariance and cross covariance functions for a turbulent flow field based on Poisson sampled measurements in time from a laser velocimeter is described. The device will process a block of data that is up to 4096 data points in length and return a 512 point covariance function with 48-bit resolution along with a 512 point histogram of the interarrival times which is used to normalize the covariance function. The device is designed to interface and be controlled by a minicomputer from which the data is received and the results returned. A typical 4096 point computation takes approximately 1.5 seconds to receive the data, compute the covariance function, and return the results to the computer.

Full Multigrid Flow Solver

NASA Technical Reports Server (NTRS)

Mineck, Raymond E.; Thomas, James L.; Biedron, Robert T.; Diskin, Boris

2005-01-01

FMG3D (full multigrid 3 dimensions) is a pilot computer program that solves equations of fluid flow using a finite difference representation on a structured grid. Infrastructure exists for three dimensions but the current implementation treats only two dimensions. Written in Fortran 90, FMG3D takes advantage of the recursive subroutine feature, dynamic memory allocation, and structured-programming constructs of that language. FMG3D supports multi-block grids with three types of block-to-block interfaces: periodic, C-zero, and C-infinity. For all three types, grid points must match at interfaces. For periodic and C-infinity types, derivatives of grid metrics must be continuous at interfaces. The available equation sets are as follows: scalar elliptic equations, scalar convection equations, and the pressure-Poisson formulation of the Navier-Stokes equations for an incompressible fluid. All the equation sets are implemented with nonzero forcing functions to enable the use of user-specified solutions to assist in verification and validation. The equations are solved with a full multigrid scheme using a full approximation scheme to converge the solution on each succeeding grid level. Restriction to the next coarser mesh uses direct injection for variables and full weighting for residual quantities; prolongation of the coarse grid correction from the coarse mesh to the fine mesh uses bilinear interpolation; and prolongation of the coarse grid solution uses bicubic interpolation.

Surface morphology diagram for cylinder-forming block copolymer thin films.

PubMed

Zhang, Xiaohua; Berry, Brian C; Yager, Kevin G; Kim, Sangcheol; Jones, Ronald L; Satija, Sushil; Pickel, Deanna L; Douglas, Jack F; Karim, Alamgir

2008-11-25

We investigate the effect of the ordering temperature (T) and film thickness (h(f)) on the surface morphology of flow-coated block copolymer (BCP) films of asymmetric poly(styrene-block-methyl methacrylate). Morphology transitions observed on the ordered film surface by atomic force microscopy (AFM) are associated with a perpendicular to a parallel cylinder BCP microphase orientation transition with respect to the substrate with increasing h(f). "Hybrid" surface patterns for intermediate h(f) between these limiting morphologies are correspondingly interpreted by a coexistence of these two BCP microphase orientations so that two "transitional" h(f) exist for each T. This explanation of our surface patterns is supported by both neutron reflectivity and rotational SANS measurements. The transitional h(f) values as a function of T define upper and lower surface morphology transition lines, h(fu) (T) and h(fl) (T), respectively, and a surface morphology diagram that should be useful in materials fabrication. Surprisingly, the BCP film surface morphology depends on the method of film formation (flow-coated versus spun-cast films) so that nonequilibrium effects are evidently operative. This morphological variability is attributed primarily to the trapping of residual solvent (toluene) within the film (quantified by neutron reflectivity) due to film vitrification while drying. This effect has significant implications for controlling film structure in nanomanufacturing applications based on BCP templates.

Predictive modelling-based design and experiments for synthesis and spinning of bioinspired silk fibres

PubMed Central

Gronau, Greta; Jacobsen, Matthew M.; Huang, Wenwen; Rizzo, Daniel J.; Li, David; Staii, Cristian; Pugno, Nicola M.; Wong, Joyce Y.; Kaplan, David L.; Buehler, Markus J.

2016-01-01

Scalable computational modelling tools are required to guide the rational design of complex hierarchical materials with predictable functions. Here, we utilize mesoscopic modelling, integrated with genetic block copolymer synthesis and bioinspired spinning process, to demonstrate de novo materials design that incorporates chemistry, processing and material characterization. We find that intermediate hydrophobic/hydrophilic block ratios observed in natural spider silks and longer chain lengths lead to outstanding silk fibre formation. This design by nature is based on the optimal combination of protein solubility, self-assembled aggregate size and polymer network topology. The original homogeneous network structure becomes heterogeneous after spinning, enhancing the anisotropic network connectivity along the shear flow direction. Extending beyond the classical polymer theory, with insights from the percolation network model, we illustrate the direct proportionality between network conductance and fibre Young's modulus. This integrated approach provides a general path towards de novo functional network materials with enhanced mechanical properties and beyond (optical, electrical or thermal) as we have experimentally verified. PMID:26017575

Predictive modelling-based design and experiments for synthesis and spinning of bioinspired silk fibres.

PubMed

Lin, Shangchao; Ryu, Seunghwa; Tokareva, Olena; Gronau, Greta; Jacobsen, Matthew M; Huang, Wenwen; Rizzo, Daniel J; Li, David; Staii, Cristian; Pugno, Nicola M; Wong, Joyce Y; Kaplan, David L; Buehler, Markus J

2015-05-28

Scalable computational modelling tools are required to guide the rational design of complex hierarchical materials with predictable functions. Here, we utilize mesoscopic modelling, integrated with genetic block copolymer synthesis and bioinspired spinning process, to demonstrate de novo materials design that incorporates chemistry, processing and material characterization. We find that intermediate hydrophobic/hydrophilic block ratios observed in natural spider silks and longer chain lengths lead to outstanding silk fibre formation. This design by nature is based on the optimal combination of protein solubility, self-assembled aggregate size and polymer network topology. The original homogeneous network structure becomes heterogeneous after spinning, enhancing the anisotropic network connectivity along the shear flow direction. Extending beyond the classical polymer theory, with insights from the percolation network model, we illustrate the direct proportionality between network conductance and fibre Young's modulus. This integrated approach provides a general path towards de novo functional network materials with enhanced mechanical properties and beyond (optical, electrical or thermal) as we have experimentally verified.

Transparent Nanofibrous Mesh Self-Assembled from Molecular LEGOs for High Efficiency Air Filtration with New Functionalities.

PubMed

Singh, Varun Kumar; Ravi, Sai Kishore; Sun, Wanxin; Tan, Swee Ching

2017-02-01

Alarming levels of particulate matter pollution in air pose a serious health threat in several countries, therefore intriguing a strong need for an economic and a viable technology of air filtration. Current air purification technology is rather expensive with certain types even having the risk of emitting hazardous by-products. The authors have developed a multifunctional air filter inspired from the nasal hairs possessing an ability to specifically trap/exhale the foreign particles and allergens while still letting the air flow. This design is achieved by introducing different functionalities at different dimensional scale employing a bottom-up approach starting with an organic molecule which is further self-organized to form nanoparticles and ultimately to a nanofibrous mesh. While the molecular building block inherently possesses the property of shielding Ultraviolet (UV) rays, the nanofibrous mesh built up from it aids in trapping the particulate matter while maintaining good air flow. By controlling the concentration of the organic molecule, the formation of fibers has been enabled in the nanoscale regime to obtain high particle-capture possibilities. The self-assembled nanofibrous filter thus designed has achieved a high filtration efficiency of ≈90% for the PM 2.5 particle in congruence with the ability to block the harmful UV radiations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of PET instrumentation for brain activation studies

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

Dahlbom, M.; Cherry, S.R.; Hoffman, E.J.

By performing cerebral blood flow studies with positron emission tomography (PET), and comparing blood flow images of different states of activation, functional mapping of the brain is possible. The ability of current commercial instruments to perform such studies is investigated in this work, based on a comparison of noise equivalent count (NEC) rates. Differences in the NEC performance of the different scanners in conjunction with scanner design parameters, provide insights into the importance of block design (size, dead time, crystal thickness) and overall scanner design (sensitivity and scatter fraction) for optimizing data from activation studies. The newer scanners with removablemore » septa, operating with 3-D acquisition, have much higher sensitivity, but require new methodology for optimized operation. Only by administering multiple low doses (fractionation) of the flow tracer can the high sensitivity be utilized.« less

Flow Separation

DTIC Science & Technology

1975-11-01

PLENUM CHAMBER 4 DIFFUSER 2 FIXEn NOZZLE BLOCK 5 MODEL i MOVABLE NOZZLE BLOCK 6 SUPPORT Fig. 3. Trl-Color Filter ...boun- dary layer ( Model 2) to examine scaling effects. Special attention was paid to the phenomenon of flow separation in three dimensions...consequence. Special attention should be paid to the difference in scale of an average boundary layer thickness between Model 1 and 2. Because

Local motion compensation in image sequences degraded by atmospheric turbulence: a comparative analysis of optical flow vs. block matching methods

NASA Astrophysics Data System (ADS)

Huebner, Claudia S.

2016-10-01

As a consequence of fluctuations in the index of refraction of the air, atmospheric turbulence causes scintillation, spatial and temporal blurring as well as global and local image motion creating geometric distortions. To mitigate these effects many different methods have been proposed. Global as well as local motion compensation in some form or other constitutes an integral part of many software-based approaches. For the estimation of motion vectors between consecutive frames simple methods like block matching are preferable to more complex algorithms like optical flow, at least when challenged with near real-time requirements. However, the processing power of commercially available computers continues to increase rapidly and the more powerful optical flow methods have the potential to outperform standard block matching methods. Therefore, in this paper three standard optical flow algorithms, namely Horn-Schunck (HS), Lucas-Kanade (LK) and Farnebäck (FB), are tested for their suitability to be employed for local motion compensation as part of a turbulence mitigation system. Their qualitative performance is evaluated and compared with that of three standard block matching methods, namely Exhaustive Search (ES), Adaptive Rood Pattern Search (ARPS) and Correlation based Search (CS).

Fuel Regression Characteristics of Cascaded Multistage Impinging-Jet (CAMUI) Type Hybrid Rocket

NASA Astrophysics Data System (ADS)

Itoh, Mitsunori; Maeda, Takenori; Kakikura, Akihito; Kaneko, Yudai; Mori, Kazuhiro; Nakashima, Takuji; Wakita, Masashi; Uematsu, Tsutomu; Totani, Tsuyoshi; Oshima, Nobuyuki; Nagata, Harunori

A series of lab-scale firing tests was conducted to investigate the fuel regression characteristics of Cascaded Multistage Impinging-jet (CAMUI) type hybrid rocket. The alternative fuel grain used in this rocket consists of a number of cylindrical fuel blocks with two ports, which were aligned along the axis of the combustion chamber with a small gap. The ports are aligned staggered with respect to ones of neighboring blocks so that the combustion gas flow impinges on the forward-end surface of each block. In this fuel grain, forward-end surfaces, back-end surfaces and ports of fuel blocks contribute as burning surfaces. Polyethylene and LOX were used as a propellant, and the tests were conducted at the chamber pressure of 0.5 2MPa and the mass flux of 50 200kg/m2s. Main results obtained in this study are in the followings: The regression rate of each surface was obtained as a function of the propellant mass flux and local equivalent ratio of the combustion gas. At back-end surfaces the regression rate has a high sensitivity on the gap height of neighboring fuel blocks. These fuel regression characteristics will contribute as fundamental data to improve the optimum design of the fuel grain.

Effect of laryngeal anesthesia on pulmonary function testing in normal subjects.

PubMed

Kuna, S T; Woodson, G E; Sant'Ambrogio, G

1988-03-01

Pulmonary function tests (PFT) were performed on 11 normal subjects before and after topical anesthesia of the larynx. The PFT consisted of flow volume loops and body box determinations of functional residual capacity and airway resistance, each performed in triplicate. After the first set of tests, cotton pledgets soaked in 4% lidocaine were held in the pyriform sinuses for 2 min to block the superior laryngeal nerves. In addition, 1.5 ml of 10% cocaine was dropped on the vocal cords via indirect laryngoscopy. PFT were repeated 5 min after anesthesia. Besides routine analysis of the flow volume loops, areas under the inspiratory (Area I) and expiratory (Area E) portions of the loops were calculated by planimetry. Area I, peak inspiratory flow (PIF), as well as forced inspiratory flow at 25, 50, and 75% forced vital capacity (FVC), decreased after anesthesia. Peak expiratory flow decreased after anesthesia, but Area E and forced expiratory flow at 25, 50, and 75% FVC were unchanged. This protocol also was performed in 12 normal subjects with isotonic saline being substituted for the lidocaine and cocaine. In this group, no significant differences were observed when flow volume loop parameters were compared before and after topical application of saline. In 5 spontaneously breathing anesthetized dogs, posterior cricoarytenoid muscle and afferent superior laryngeal nerve activity were recorded before and after laryngeal anesthesia performed with the same procedure used in the human subjects. Laryngeal anesthesia resulted in a substantial decrease or a complete disappearance of afferent SLN activity recorded during unobstructed and obstructed respiration. The data suggest that laryngeal receptors help modulate upper airway patency in man.

Effect of atrial systole on canine and porcine coronary blood flow.

PubMed

Bellamy, R F

1981-09-01

A feature of phasic coronary flow patterns recorded in conscious chronically instrumented dogs is the atrial cove--a transient depression of arterial flow that occurs during atrial systole. The association between the hemodynamic effects of atrial systole and the atrial cove was studied in anesthetized dogs and pigs with complete heart block. Many atrial coves are available for study in these preparations because atrial activity continues unabated during the diastolic ventricular arrest that follows cessation of electrical pacing. The effect of atrial systole is to translate the pressure-flow relation found during diastole to a higher intercept pressure without change in slope. The increase in the intercept pressure equals the increase in intramyocardial pressure measured with microtransducers embedded in the left ventricular wall. The decrement in flow during the atrial cove is a direct function of the change in intramyocardial pressure and an inverse function of coronary vascular resistance. Each atrial systole is associated with a forward flow transient in the coronary veins, the peak of which occurs at the same instant as does the nadir of atrial flow. These data suggest that the coronary vessels are acting as collapsible tubes and that the waterfall model of the coronary circulation is applicable. The following sequence is proposed to account for the atrial cove. Atrial systole ejects a bolus of blood into the left ventricle increasing both ventricular cavity and intramyocardial pressures. The increase in intramyocardial pressure raises the back pressure opposing coronary flow, reducing the arterial perfusion pressure gradient and causing flow to fall.

A multi-block adaptive solving technique based on lattice Boltzmann method

NASA Astrophysics Data System (ADS)

Zhang, Yang; Xie, Jiahua; Li, Xiaoyue; Ma, Zhenghai; Zou, Jianfeng; Zheng, Yao

2018-05-01

In this paper, a CFD parallel adaptive algorithm is self-developed by combining the multi-block Lattice Boltzmann Method (LBM) with Adaptive Mesh Refinement (AMR). The mesh refinement criterion of this algorithm is based on the density, velocity and vortices of the flow field. The refined grid boundary is obtained by extending outward half a ghost cell from the coarse grid boundary, which makes the adaptive mesh more compact and the boundary treatment more convenient. Two numerical examples of the backward step flow separation and the unsteady flow around circular cylinder demonstrate the vortex structure of the cold flow field accurately and specifically.

Modeling air concentration over macro roughness conditions by Artificial Intelligence techniques

NASA Astrophysics Data System (ADS)

Roshni, T.; Pagliara, S.

2018-05-01

Aeration is improved in rivers by the turbulence created in the flow over macro and intermediate roughness conditions. Macro and intermediate roughness flow conditions are generated by flows over block ramps or rock chutes. The measurements are taken in uniform flow region. Efficacy of soft computing methods in modeling hydraulic parameters are not common so far. In this study, modeling efficiencies of MPMR model and FFNN model are found for estimating the air concentration over block ramps under macro roughness conditions. The experimental data are used for training and testing phases. Potential capability of MPMR and FFNN model in estimating air concentration are proved through this study.

Numerical analysis of mixing enhancement for micro-electroosmotic flow

NASA Astrophysics Data System (ADS)

Tang, G. H.; He, Y. L.; Tao, W. Q.

2010-05-01

Micro-electroosmotic flow is usually slow with negligible inertial effects and diffusion-based mixing can be problematic. To gain an improved understanding of electroosmotic mixing in microchannels, a numerical study has been carried out for channels patterned with wall blocks, and channels patterned with heterogeneous surfaces. The lattice Boltzmann method has been employed to obtain the external electric field, electric potential distribution in the electrolyte, the flow field, and the species concentration distribution within the same framework. The simulation results show that wall blocks and heterogeneous surfaces can significantly disturb the streamlines by fluid folding and stretching leading to apparently substantial improvements in mixing. However, the results show that the introduction of such features can substantially reduce the mass flow rate and thus effectively prolongs the available mixing time when the flow passes through the channel. This is a non-negligible factor on the effectiveness of the observed improvements in mixing efficiency. Compared with the heterogeneous surface distribution, the wall block cases can achieve more effective enhancement in the same mixing time. In addition, the field synergy theory is extended to analyze the mixing enhancement in electroosmotic flow. The distribution of the local synergy angle in the channel aids to evaluate the effectiveness of enhancement method.

Sensing fluid pressure during plucking events in a natural bedrock channel and experimental flume

NASA Astrophysics Data System (ADS)

Wilkinson, C.; Harbor, D. J.; Keel, D.; Levy, S.; Kuehner, J. P.

2016-12-01

River channel erosion by plucking is believed to be the dominant erosional process in channels with fractured or jointed bedrock. However, despite its significance as an erosional mechanism, plucking is poorly studied in both laboratory and natural channels. In previous flume studies, model bedrock was plucked by fluid forces alone in nonuniform flow near jumps and waves even where blocks do not protrude into the flow. Here we develop sensor systems to test the hypothesis that bed fluid pressure gradients lift "pluckable" bedrock blocks in a natural field setting and a hydraulic flume. The field setting closely mimics the previous flume setup; the instrumented block is downstream of a roughly 1m step and exhibits no protrusion into the flow. The presence of the step promotes nonuniform flow which changes pressure in the bedrock crack network; slabs of bedrock that have slid downstream and sediment that has been pushed upstream 3-4 m under the bed and in the cracks suggest the influence of pressure differences throughout the crack network and below the bed. In this initial deployment, we evaluate a sensor that monitors movement and simultaneous pressure above and below the block. Sensors are emplaced in a 26kg, 45-cm-long, 20-cm-wide block broken from a 4.5-m-long, 11-cm-thick sandstone bed with a dense network of cracks nearly parallel to flow direction and include a tri-axial accelerometer/gyroscope and two fluid pressure sensors. The electronics are housed in a custom-designed 3D-printed ABS waterproof capsule that is mounted in a vertical hole through the rock. A concurrent flume study develops the sensors necessary to investigate the longitudinal pressure difference below a step using multiple analog sensors (0-1 psi gauge pressure) mounted flush to a false floor under the center of a 30x14-cm test zone. The 15-mm-wide sensors are aligned along the flow centerline and are placed under 25 1-cm-thick "pluckable" bedrock blocks constructed with a proprietary plaster cement. Measured mean pressure and transmission of pressure pulses under the test bed are compared to the visual record of plucking. In addition, conducting runs with blocks removed permits simulation of the mean and varying pressure conditions above the modeled "pluckable" layer as a hydraulic jump is moved downstream through the step.

FANS-3D Users Guide (ESTEP Project ER 201031)

DTIC Science & Technology

2016-08-01

governing laminar and turbulent flows in body-fitted curvilinear grids. The code employs multi-block overset ( chimera ) grids, including fully matched...governing incompressible flow in body-fitted grids. The code allows for multi-block overset ( chimera ) grids, which can be fully matched, arbitrarily...interested reader may consult the Chimera Overset Structured Mesh-Interpolation Code (COSMIC) Users’ Manual (Chen, 2009). The input file used for

Study of limitations and attributes of microprocessor testing techniques

NASA Technical Reports Server (NTRS)

Mccaskill, R.; Sohl, W. E.

1977-01-01

All microprocessor units have a similar architecture from which a basic test philosophy can be adopted and used to develop an approach to test each module separately in order to verify the functionality of each module within the device using the input/output pins of the device and its instruction set; test for destructive interaction between functional modules; and verify all timing, status information, and interrupt operations of the device. Block and test flow diagrams are given for the 8080, 8008, 2901, 6800, and 1802 microprocessors. Manufacturers are listed and problems encountered in testing the modules are discussed. Test equipment and methods are described.

On Painlevé/gauge theory correspondence

NASA Astrophysics Data System (ADS)

Bonelli, Giulio; Lisovyy, Oleg; Maruyoshi, Kazunobu; Sciarappa, Antonio; Tanzini, Alessandro

2017-12-01

We elucidate the relation between Painlevé equations and four-dimensional rank one N = 2 theories by identifying the connection associated with Painlevé isomonodromic problems with the oper limit of the flat connection of the Hitchin system associated with gauge theories and by studying the corresponding renormalization group flow. Based on this correspondence, we provide long-distance expansions at various canonical rays for all Painlevé τ -functions in terms of magnetic and dyonic Nekrasov partition functions for N = 2 SQCD and Argyres-Douglas theories at self-dual Omega background ɛ _1 + ɛ _2 = 0 or equivalently in terms of c=1 irregular conformal blocks.

Numerical Solutions for Laminar Boundary Layer Behind Blast Waves.

DTIC Science & Technology

1980-05-01

DISTRIBUTION STATEMENT (of thle Report) Approved for public release; distribution unlimited. 17 . DISTRIBUTION STATEMENT (of the abstract entered in Block 20...Reference I ............. 41 5. Boundary-Layer Functions for Case A, B, C, and D ......... 98 3 NOMENCLATURE A constant, Eqs. (10) and ( 17 ) B...the constant A was chosen as follows to simplify the coefficients of f and g1 A = 2mF CZ(a+i) OPO/pCO ( The ( 17 ) The explicit dependence of the flow

Blocking, descent and gravity waves: Observations and modelling of a MAP northerly föhn event

NASA Astrophysics Data System (ADS)

Jiang, Qingfang; Doyle, James D.; Smith, Ronald B.

2005-01-01

A northerly föhn event observed during the special observational period of the Mesoscale Alpine Programme is investigated based on observational analysis and numerical modelling. The focus of this study includes three dynamical processes associated with mountain perturbations and their interactions, namely, windward flow blocking, descent and warming on the lee side, and mountain waves. Observations indicate the presence of a deep weak-flow layer underneath a stable layer, associated with Alpine-scale blocking. Satellite imagery reveals a föhninduced cloud-free area to the south of the Alps, which is consistent with flow descent diagnosed from radiosondes and constant-volume balloons. Moderate-amplitude stationary waves were observed by research aircraft over the major Alpine peaks. Satellite images and balloon data indicate the presence of stationary trapped-wave patterns located to the north of the Alpine massif.Satisfactory agreement is found between observations and a real-data COAMPS simulation nested to 1 km resolution. COAMPS indicates the presence of trapped waves associated with a sharp decrease of Scorer parameter above a stable layer in the mid-troposphere. Underneath the stable layer, moist low-level flow is blocked to the north of the Alps. The warm air in the stable layer descends in the lee and recovers its altitude over a relatively short horizontal distance through a hydraulic jump.Blocking reduces the effective mountain and hence significantly reduces mountain drag. A simple empirical formula for estimation of the effective mountain height, he, is derived based on numerical simulations. The formula states he/hc = (h/hc), where h is the real mountain height and hc is the critical mountain height to have flow stagnation.

Scale problems in assessment of hydrogeological parameters of groundwater flow models

NASA Astrophysics Data System (ADS)

Nawalany, Marek; Sinicyn, Grzegorz

2015-09-01

An overview is presented of scale problems in groundwater flow, with emphasis on upscaling of hydraulic conductivity, being a brief summary of the conventional upscaling approach with some attention paid to recently emerged approaches. The focus is on essential aspects which may be an advantage in comparison to the occasionally extremely extensive summaries presented in the literature. In the present paper the concept of scale is introduced as an indispensable part of system analysis applied to hydrogeology. The concept is illustrated with a simple hydrogeological system for which definitions of four major ingredients of scale are presented: (i) spatial extent and geometry of hydrogeological system, (ii) spatial continuity and granularity of both natural and man-made objects within the system, (iii) duration of the system and (iv) continuity/granularity of natural and man-related variables of groundwater flow system. Scales used in hydrogeology are categorised into five classes: micro-scale - scale of pores, meso-scale - scale of laboratory sample, macro-scale - scale of typical blocks in numerical models of groundwater flow, local-scale - scale of an aquifer/aquitard and regional-scale - scale of series of aquifers and aquitards. Variables, parameters and groundwater flow equations for the three lowest scales, i.e., pore-scale, sample-scale and (numerical) block-scale, are discussed in detail, with the aim to justify physically deterministic procedures of upscaling from finer to coarser scales (stochastic issues of upscaling are not discussed here). Since the procedure of transition from sample-scale to block-scale is physically well based, it is a good candidate for upscaling block-scale models to local-scale models and likewise for upscaling local-scale models to regional-scale models. Also the latest results in downscaling from block-scale to sample scale are briefly referred to.

Gap Flows through Idealized Topography. Part I: Forcing by Large-Scale Winds in the Nonrotating Limit.

NASA Astrophysics Data System (ADS)

Gabersek, Sasa.; Durran, Dale R.

2004-12-01

Gap winds produced by a uniform airstream flowing over an isolated flat-top ridge cut by a straight narrow gap are investigated by numerical simulation. On the scale of the entire barrier, the proportion of the oncoming flow that passes through the gap is relatively independent of the nondimensional mountain height , even over that range of for which there is the previously documented transition from a “flow over the ridge” regime to a “flow around” regime.The kinematics and dynamics of the gap flow itself were investigated by examining mass and momentum budgets for control volumes at the entrance, central, and exit regions of the gap. These analyses suggest three basic behaviors: the linear regime (small ) in which there is essentially no enhancement of the gap flow; the mountain wave regime ( 1.5) in which vertical mass and momentum fluxes play a crucial role in creating very strong winds near the exit of the gap; and the upstream-blocking regime ( 5) in which lateral convergence generates the strongest winds near the entrance of the gap.Trajectory analysis of the flow in the strongest events, the mountain wave events, confirms the importance of net subsidence in creating high wind speeds. Neglect of vertical motion in applications of Bernoulli's equation to gap flows is shown to lead to unreasonable wind speed predictions whenever the temperature at the gap exit exceeds that at the gap entrance. The distribution of the Bernoulli function on an isentropic surface shows a correspondence between regions of high Bernoulli function and high wind speeds in the gap-exit jet similar to that previously documented for shallow-water flow.

Fluid flow stimulates rapid and continuous release of nitric oxide in osteoblasts

NASA Technical Reports Server (NTRS)

Johnson, D. L.; McAllister, T. N.; Frangos, J. A.

1996-01-01

Interstitial fluid flow may mediate skeletal remodeling in response to mechanical loading. Because nitric oxide (NO) has been shown to be an osteoblast mitogen and inhibitor of osteoclastic resorption, we investigated and characterized the role of fluid shear on the release of NO in osteoblasts. Rat calvarial cells in a stationary culture produced undetectable levels of NO. Fluid shear stress (6 dyn/cm2) rapidly increased NO release rate to 9.8 nmol.h-1.mg protein-1 and sustained this production for 12 h of exposure to flow. Cytokine treatment also induced NO synthesis after a 12-h lag phase of zero production, followed by a production rate of 0.6 nmol.h-1.mg protein-1. Flow-induced NO production was blocked by the NO synthase (NOS) inhibitor NG-amino-L-arginine, but not by dexamethasone, which suggests that the flow stimulated a constitutive NOS isoform. This is the first time that a functional constitutively present NOS isoform has been identified in osteoblasts. Moreover, fluid flow represents the most potent stimulus of NO release in osteoblasts reported to date. Fluid flow-induced NO production may therefore play a primary role in bone maintenance and remodeling.

Turbulent Structure of a Simplified Urban Fluid Flow Studied Through Stereoscopic Particle Image Velocimetry

NASA Astrophysics Data System (ADS)

Monnier, Bruno; Goudarzi, Sepehr A.; Vinuesa, Ricardo; Wark, Candace

2018-02-01

Stereoscopic particle image velocimetry was used to provide a three-dimensional characterization of the flow around a simplified urban model defined by a 5 by 7 array of blocks, forming four parallel streets, perpendicular to the incoming wind direction corresponding to a zero angle of incidence. Channeling of the flow through the array under consideration was observed, and its effect increased as the incoming wind direction, or angle of incidence ( AOI), was changed from 0° to 15°, 30°, and 45°. The flow between blocks can be divided into two regions: a region of low turbulence kinetic energy (TKE) levels close to the leeward side of the upstream block, and a high TKE area close to the downstream block. The centre of the arch vortex is located in the low TKE area, and two regions of large streamwise velocity fluctuation bound the vortex in the spanwise direction. Moreover, a region of large spanwise velocity fluctuation on the downstream block is found between the vortex legs. Our results indicate that the reorientation of the arch vortex at increasing AOI is produced by the displacement of the different TKE regions and their interaction with the shear layers on the sides and top of the upstream and downstream blocks, respectively. There is also a close connection between the turbulent structure between the blocks and the wind gusts. The correlations among gust components were also studied, and it was found that in the near-wall region of the street the correlations between the streamwise and spanwise gusts R_{uv} were dominant for all four AOI cases. At higher wall-normal positions in the array, the R_{uw} correlation decreased with increasing AOI, whereas the R_{uv} coefficient increased as AOI increased, and at {it{AOI}}=45° all three correlations exhibited relatively high values of around 0.4.

A programmable and portable NMES device for drop foot correction and blood flow assist applications.

PubMed

Breen, Paul P; Corley, Gavin J; O'Keeffe, Derek T; Conway, Richard; Olaighin, Gearóid

2009-04-01

The Duo-STIM, a new, programmable and portable neuromuscular stimulation system for drop foot correction and blood flow assist applications is presented. The system consists of a programmer unit and a portable, programmable stimulator unit. The portable stimulator features fully programmable, sensor-controlled, constant-voltage, dual-channel stimulation and accommodates a range of customized stimulation profiles. Trapezoidal and free-form adaptive stimulation intensity envelope algorithms are provided for drop foot correction applications, while time dependent and activity dependent algorithms are provided for blood flow assist applications. A variety of sensor types can be used with the portable unit, including force sensitive resistor-based foot switches and MEMS-based accelerometer and gyroscope devices. The paper provides a detailed description of the hardware and block-level system design for both units. The programming and operating procedures for the system are also presented. Finally, functional bench test results for the system are presented.

A programmable and portable NMES device for drop foot correction and blood flow assist applications.

PubMed

Breen, Paul P; Corley, Gavin J; O'Keeffe, Derek T; Conway, Richard; OLaighin, Gearoid

2007-01-01

The Duo-STIM, a new, programmable and portable neuromuscular stimulation system for drop foot correction and blood flow assist applications is presented. The system consists of a programmer unit and a portable, programmable stimulator unit. The portable stimulator features fully programmable, sensor-controlled, constant-voltage, dual-channel stimulation and accommodates a range of customized stimulation profiles. Trapezoidal and free-form adaptive stimulation intensity envelope algorithms are provided for drop foot correction applications, while time dependent and activity dependent algorithms are provided for blood flow assist applications. A variety of sensor types can be used with the portable unit, including force sensitive resistor based foot switches and NMES based accelerometer and gyroscope devices. The paper provides a detailed description of the hardware and block-level system design for both units. The programming and operating procedures for the system are also presented. Finally, functional bench test results for the system are presented.

Mathematical model of an indirect action fuel flow controller for aircraft jet engines

NASA Astrophysics Data System (ADS)

Tudosie, Alexandru-Nicolae

2017-06-01

The paper deals with a fuel mass flow rate controller with indirect action for aircraft jet engines. The author has identified fuel controller's main parts and its operation mode, then, based on these observations, one has determined motion equations of each main part, which have built system's non-linear mathematical model. In order to realize a better study this model was linearised (using the finite differences method) and then adimensionalized. Based on this new form of the mathematical model, after applying Laplace transformation, the embedded system (controller+engine) was described by the block diagram with transfer functions. Some Simulink-Matlab simulations were performed, concerning system's time behavior for step input, which lead to some useful conclusions and extension possibilities.

Rockslide-debris avalanche of May 18, 1980, Mount St. Helens Volcano, Washington

USGS Publications Warehouse

Glicken, Harry

1996-01-01

This report provides a detailed picture of the rockslide-debris avalanche of the May 18, 1980, eruption of Mount St. Helens volcano. It provides a characterization of the deposit, a reinterpretation of the details of the first minutes of the eruption of May 18, and insight into the transport mechanism of the mass movement. Details of the rockslide event, as revealed by eyewitness photographs, are correlated with features of the deposit. The photographs show three slide blocks in the rockslide movement. Slide block I was triggered by a magnitude 5.1 earthquake at 8:32 a.m. Pacific Daylight Time (P.D.T.). An exploding cryptodome burst through slide block II to produce the 'blast surge.' Slide block III consisted of many discrete failures that were carried out in continuing pyroclastic currents generated from the exploding cryptodome. The cryptodome continued to depressurize after slide block III, producing a blast deposit that rests on top of the debris-avalanche deposit. The hummocky 2.5 cubic kilometer debris-avalanche deposit consists of block facies (pieces of the pre-eruption Mount St. Helens transported relatively intact) and matrix facies (a mixture of rocks from the old mountain and cryptodome dacite). Block facies is divided into five lithologic units. Matrix facies was derived from the explosively generated current of slide block III as well as from disaggregation and mixing of debris-avalanche blocks. The mean density of the old cone was measured to be abut 20 percent greater than the mean density of the avalanche deposit. Density in the deposit does not decrease with distance which suggests that debris-avalanche blocks were dilated at the mountain, rather than during transport. Various grain-size parameters that show that clast size converges about a mean with distance suggest mixing during transport. The debris-avalanche flow can be considered a grain flow, where particles -- either debris-avalanche blocks or the clasts within the blocks -- collided and created dispersive stress normal to the movement of material. The dispersive stress preserved the dilation of the material and allowed it to flow.

Investigation on the Core Bypass Flow in a Very High Temperature Reactor

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

Hassan, Yassin

2013-10-22

Uncertainties associated with the core bypass flow are some of the key issues that directly influence the coolant mass flow distribution and magnitude, and thus the operational core temperature profiles, in the very high-temperature reactor (VHTR). Designers will attempt to configure the core geometry so the core cooling flow rate magnitude and distribution conform to the design values. The objective of this project is to study the bypass flow both experimentally and computationally. Researchers will develop experimental data using state-of-the-art particle image velocimetry in a small test facility. The team will attempt to obtain full field temperature distribution using racksmore » of thermocouples. The experimental data are intended to benchmark computational fluid dynamics (CFD) codes by providing detailed information. These experimental data are urgently needed for validation of the CFD codes. The following are the project tasks: • Construct a small-scale bench-top experiment to resemble the bypass flow between the graphite blocks, varying parameters to address their impact on bypass flow. Wall roughness of the graphite block walls, spacing between the blocks, and temperature of the blocks are some of the parameters to be tested. • Perform CFD to evaluate pre- and post-test calculations and turbulence models, including sensitivity studies to achieve high accuracy. • Develop the state-of-the art large eddy simulation (LES) using appropriate subgrid modeling. • Develop models to be used in systems thermal hydraulics codes to account and estimate the bypass flows. These computer programs include, among others, RELAP3D, MELCOR, GAMMA, and GAS-NET. Actual core bypass flow rate may vary considerably from the design value. Although the uncertainty of the bypass flow rate is not known, some sources have stated that the bypass flow rates in the Fort St. Vrain reactor were between 8 and 25 percent of the total reactor mass flow rate. If bypass flow rates are on the high side, the quantity of cooling flow through the core may be considerably less than the nominal design value, causing some regions of the core to operate at temperatures in excess of the design values. These effects are postulated to lead to localized hot regions in the core that must be considered when evaluating the VHTR operational and accident scenarios.« less

Clogging and transport of driven particles in asymmetric funnel arrays

NASA Astrophysics Data System (ADS)

Reichhardt, C. J. O.; Reichhardt, C.

2018-06-01

We numerically examine the flow and clogging of particles driven through asymmetric funnel arrays when the commensurability ratio of the number of particles per plaquette is varied. The particle–particle interactions are modeled with a soft repulsive potential that could represent vortex flow in type-II superconductors or driven charged colloids. The velocity-force curves for driving in the easy flow direction of the funnels exhibit a single depinning threshold; however, for driving in the hard flow direction, we find that there can be both negative mobility where the velocity decreases with increasing driving force as well as a reentrant pinning effect in which the particles flow at low drives but become pinned at intermediate drives. This reentrant pinning is associated with a transition from smooth 1D flow at low drives to a clogged state at higher drives that occurs when the particles cluster in a small number of plaquettes and block the flow. When the drive is further increased, particle rearrangements occur that cause the clog to break apart. We map out the regimes in which the pinned, flowing, and clogged states appear as a function of plaquette filling and drive. The clogged states remain robust at finite temperatures but develop intermittent bursts of flow in which a clog temporarily breaks apart but quickly reforms.

Pyroclastic flow generated by crater-wall collapse and outpouring of the lava pool of Arenal Volcano, Costa Rica

NASA Astrophysics Data System (ADS)

Alvarado, Guillermo E.; Soto, Gerardo J.

2002-01-01

The pyroclastic flow that issued from the Arenal summit crater on 28 August 1993 came from the collapse of the crater wall of the cone and the drainage of a lava pool. The 3-km-long pyroclastic flow, 2.2±0.8×106 m3 in volume, was confined to narrow valleys (30-100 m wide). The thickness of the pyroclastic deposit ranged from 1 to 10 m, and its temperature was about 400 °C, although single bombs were up to 1,000 °C. The deposit is clast-supported, has a bimodal grain size distribution, and consists of an intimate mixture of finely pulverized rock ash, lapilli, small blocks, and cauliflower bread-crusted bombs, in which are set meter-size lava fragments and juvenile and non-juvenile angular blocks, and bombs up to 7 m in diameter. Large faceted blocks make up 50% of the total volume of the deposit. The cauliflower bombs have deep and intricate bread-crust texture and post-depositional vesiculation. It is proposed that the juvenile material was produced entirely from a lava pool, whereas faceted non-juvenile blocks come from the crater-wall collapse. The concentration and maximum diameter of cauliflower bread-crusted bombs increases significantly from the base (rockslide + pyroclastic flow) to the top (the pyroclastic flow) of the deposit. An ash cloud deposited accretionary lapilli in the proximal region (outside of the pyroclastic flow deposit), and very fine ash fell in the distal region (between 5 and 30 km). The accretionary lapilli deposit is derived from the fine, elutriated products of the flow as it moved. A turbulent overriding surge blew down the surrounding shrubbery in the flow direction. The pyroclastic flow from August 1993, similar to the flows of June 1975, May 1998, August 2000, and March 2001, slid and rolled rather than being buoyed up by gas. They grooved, scratched, and polished the surfaces over which they swept, similar to a Merapi-type pyroclastic flow. However, the mechanism of the outpouring of a lava pool and the resulting flows composed of high- to moderate-vesiculated, cauliflower bread-crusted bombs and juvenile blocks have not been described before. High-frequency earthquake swarms, followed by an increase in low-frequency volcanic events, preceded the 1975, 1993, and 2000 eruptions 2-4 months before. These pyroclastic flow events, therefore, may be triggered by internal expansion of the unstable cone in the upper part because of a slight change in the pressure of the magma column (gas content and/or effusive rate). This phenomenon has important short-term, volcanic hazard implications for touristic development of some parts on the flanks of the volcano.

Developmental defects in zebrafish for classification of EGF pathway inhibitors

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

Pruvot, Benoist; Curé, Yoann; Djiotsa, Joachim

2014-01-15

One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairmentmore » of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway. In conclusion, we show that developmental indicators can help to discriminate between specific effects on the target pathway from off-target effects in molecularly targeted drug screening experiments in whole animal systems. - Highlights: • We analyze the functions of Egf signaling on zebrafish development. • Genetic blocking of Egf expression causes cartilage, myelin and circulatory defects. • Chemical inhibition of Egf receptor function causes similar defects. • Developmental defects can reveal the specificity of Egf pathway inhibitors.« less

A scalable block-preconditioning strategy for divergence-conforming B-spline discretizations of the Stokes problem

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

Cortes, Adriano M.; Dalcin, Lisandro; Sarmiento, Adel F.

The recently introduced divergence-conforming B-spline discretizations allow the construction of smooth discrete velocity–pressure pairs for viscous incompressible flows that are at the same time inf–sup stable and pointwise divergence-free. When applied to the discretized Stokes problem, these spaces generate a symmetric and indefinite saddle-point linear system. The iterative method of choice to solve such system is the Generalized Minimum Residual Method. This method lacks robustness, and one remedy is to use preconditioners. For linear systems of saddle-point type, a large family of preconditioners can be obtained by using a block factorization of the system. In this paper, we show howmore » the nesting of “black-box” solvers and preconditioners can be put together in a block triangular strategy to build a scalable block preconditioner for the Stokes system discretized by divergence-conforming B-splines. Lastly, besides the known cavity flow problem, we used for benchmark flows defined on complex geometries: an eccentric annulus and hollow torus of an eccentric annular cross-section.« less

A scalable block-preconditioning strategy for divergence-conforming B-spline discretizations of the Stokes problem

DOE PAGES

Cortes, Adriano M.; Dalcin, Lisandro; Sarmiento, Adel F.; ...

2016-10-19

The recently introduced divergence-conforming B-spline discretizations allow the construction of smooth discrete velocity–pressure pairs for viscous incompressible flows that are at the same time inf–sup stable and pointwise divergence-free. When applied to the discretized Stokes problem, these spaces generate a symmetric and indefinite saddle-point linear system. The iterative method of choice to solve such system is the Generalized Minimum Residual Method. This method lacks robustness, and one remedy is to use preconditioners. For linear systems of saddle-point type, a large family of preconditioners can be obtained by using a block factorization of the system. In this paper, we show howmore » the nesting of “black-box” solvers and preconditioners can be put together in a block triangular strategy to build a scalable block preconditioner for the Stokes system discretized by divergence-conforming B-splines. Lastly, besides the known cavity flow problem, we used for benchmark flows defined on complex geometries: an eccentric annulus and hollow torus of an eccentric annular cross-section.« less

Block-structured grids for complex aerodynamic configurations: Current status

NASA Technical Reports Server (NTRS)

Vatsa, Veer N.; Sanetrik, Mark D.; Parlette, Edward B.

1995-01-01

The status of CFD methods based on the use of block-structured grids for analyzing viscous flows over complex configurations is examined. The objective of the present study is to make a realistic assessment of the usability of such grids for routine computations typically encountered in the aerospace industry. It is recognized at the very outset that the total turnaround time, from the moment the configuration is identified until the computational results have been obtained and postprocessed, is more important than just the computational time. Pertinent examples will be cited to demonstrate the feasibility of solving flow over practical configurations of current interest on block-structured grids.

Upscaled soil-water retention using van Genuchten's function

USGS Publications Warehouse

Green, T.R.; Constantz, J.E.; Freyberg, D.L.

1996-01-01

Soils are often layered at scales smaller than the block size used in numerical and conceptual models of variably saturated flow. Consequently, the small-scale variability in water content within each block must be homogenized (upscaled). Laboratory results have shown that a linear volume average (LVA) of water content at a uniform suction is a good approximation to measured water contents in heterogeneous cores. Here, we upscale water contents using van Genuchten's function for both the local and upscaled soil-water-retention characteristics. The van Genuchten (vG) function compares favorably with LVA results, laboratory experiments under hydrostatic conditions in 3-cm cores, and numerical simulations of large-scale gravity drainage. Our method yields upscaled vG parameter values by fitting the vG curve to the LVA of water contents at various suction values. In practice, it is more efficient to compute direct averages of the local vG parameter values. Nonlinear power averages quantify a feasible range of values for each upscaled vG shape parameter; upscaled values of N are consistently less than the harmonic means, reflecting broad pore-size distributions of the upscaled soils. The vG function is useful for modeling soil-water retention at large scales, and these results provide guidance for its application.

Southern hemisphere low level wind circulation statistics from the Seasat scatterometer

NASA Technical Reports Server (NTRS)

Levy, Gad

1994-01-01

Analyses of remotely sensed low-level wind vector data over the Southern Ocean are performed. Five-day averages and monthly means are created and the month-to-month variability during the winter (July-September) of 1978 is investigated. The remotely sensed winds are compared to the Australian Bureau of Meteorology (ABM) and the National Meteorological Center (NMC) surface analyses. In southern latitudes the remotely sensed winds are stronger than what the weather services' analyses suggest, indicating under-estimation by ABM and NMC in these regions. The evolution of the low-level jet and the major stormtracks during the season are studied and different flow regimes are identified. The large-scale variability of the meridional flow is studied with the aid of empirical orthogonal function (EOF) analysis. The dominance of quasi-stationary wave numbers 3,4, and 5 in the winter flows is evident in both the EOF analysis and the mean flow. The signature of an exceptionally strong blocking situation is evident in July and the special conditions leading to it are discussed. A very large intraseasonal variability with different flow regimes at different months is documented.

Persistence of asymmetry in nonaxisymmetric entry flow in a circular cylindrical tube and its relevance to arterial pulse wave diagnosis.

PubMed

Xue, H; Fung, Y C

1989-02-01

In an experiment motivated by the study of arterial blood flow along the lines suggested by the traditional Chinese medicine, the flow in a pipe whose lumen was blocked by a semi-circular plug two tube-diameters long was visualized by suspended particles, recorded by cinematography, and analyzed digitally. The Reynolds number was in the range of 100 to 450 based on the pipe diameter, similar to that of blood flow in the radial artery in the arms of man. The blockage was found to have a profound effect on the velocity profile of the flow in the wake, but it had little influence on the symmetry of the velocity profile upstream of the block, except in its immediate neighborhood. When the end conditions far away from the block were steady, the flow in the wake was steady. The asymmetry of the flow in the wake can be judged by the deviation of the location of the maximum axial velocity from the center line of the pipe as seen in the plane of symmetry of the blockage. Our results show that the deviation can be described as the sum of two components. The first is a strong one which decays exponentially in an entry length which is about twice as long as the classical Boussinesq entry length of axisymmetric flow. The second is a weaker component which is wavy spatially and persists far downstream (many times the entry length). The separated flow and vortex system behind the blockage are sensitive to the flow rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Selective inhibition by a synthetic hirudin peptide of fibrin-dependent thrombosis in baboons

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

Cadroy, Y.; Hanson, S.R.; Harker, L.A.

1991-02-15

To determine the importance of the thrombin substrate recognition exosite for fibrinogen binding in the formation of both arterial and venous thrombi the authors evaluated the antithrombotic effects of the tyrosine-sulfated dodecapeptide from residues 53-64 of hirudin (H peptide) in a nonhuman primate model. This peptide was studied because it inhibits thrombin cleavages of fibrinogen by simple competition without blocking enzyme catalytic-site function. When an exteriorized arteriovenous access shunt model was used in baboons (Papio anubis), thrombus formation was induced by placing a thrombogenic device made of (i) a segment of tubing coated covalently with type I collagen, which generatedmore » platelet-rich thrombi under arterial flow conditions, and (ii) two subsequent annular regions of flow expansion that produced fibrin-rich thrombi typically associated with venous valves and veins. Thrombus formation was quantified by measurements of {sup 111}In-labeled platelet and {sup 125}I-labeled fibrinogen deposition in both arterial-flow and venous-flow portions of the device. These finding suggest that, by competitive inhibition of fibrinogen binding to thrombin, fibrin-rich venous-type thrombus formation may be selectively prevented. This strategy may be therapeutically attractive for preserving normal platelet function when conventional anticoagulant therapy is contraindicated.« less

Micro-valve using induced-charge electrokinetic motion of Janus particle.

PubMed

Daghighi, Yasaman; Li, Dongqing

2011-09-07

A new micro-valve using the electrokinetic motion of a Janus particle is introduced in this paper. A Janus particle with a conducting hemisphere and a non-conducting hemisphere is placed in a junction of several microchannels. Under an applied electric field, the induced-charge electrokinetic flow around the conducting side of the Janus particle forms vortices. The vortices push the particle moving forwards to block the entrance of a microchannel. By switching the direction of the applied electric field, the motion of the Janus particle can be changed to block different microchannels. This paper develops a theoretical model and conducts numerical simulations of the three-dimensional transient motion of the Janus particle. The results show that this Janus particle-based micro-valve is feasible for switching and controlling the flow rate in a microfluidic chip. This method is simple in comparison with other types of micro-valve methods. It is easy for fabrication, for operation control, and has a fast response time. To better understand the micro-valve functions, comparisons with a non-conducting particle and a fully conducting particle were made. Results proved that only a Janus particle can fulfill the requirements of such a micro-valve.

Liquid cooling applications on automotive exterior LED lighting

NASA Astrophysics Data System (ADS)

Aktaş, Mehmet; Şenyüz, Tunç; Şenyıldız, Teoman; Kılıç, Muhsin

2018-02-01

In this study cooling of a LED unit with heatsink and liquid cooling block which is used in automotive head lamp applications has been investigated numerically and experimentally. Junction temperature of a LED which is cooled with heatsink and liquid cooling block obtained in the experiment. 23°C is used both in the simulation and the experiment phase. Liquid cooling block material is choosed aluminium (Al) and polyamide. All tests and simulation are performed with three different flow rate. Temperature distribution of the designed product is investigated by doing the numerical simulations with a commercially software. In the simulations, fluid flow is assumed to be steady, incompressible and laminar and 3 dimensional (3D) Navier-Stokes equations are used. According to the calculations it is obtained that junction temperature is higher in the heatsink design compared to block cooled one. By changing the block material, it is desired to investigate the variation on the LED junction temperature. It is found that more efficient cooling can be obtained in block cooling by using less volume and weight. With block cooling lifetime of LED can be increased and flux loss can be decreased with the result of decreased junction temperature.

Adaptive grid methods for RLV environment assessment and nozzle analysis

NASA Technical Reports Server (NTRS)

Thornburg, Hugh J.

1996-01-01

Rapid access to highly accurate data about complex configurations is needed for multi-disciplinary optimization and design. In order to efficiently meet these requirements a closer coupling between the analysis algorithms and the discretization process is needed. In some cases, such as free surface, temporally varying geometries, and fluid structure interaction, the need is unavoidable. In other cases the need is to rapidly generate and modify high quality grids. Techniques such as unstructured and/or solution-adaptive methods can be used to speed the grid generation process and to automatically cluster mesh points in regions of interest. Global features of the flow can be significantly affected by isolated regions of inadequately resolved flow. These regions may not exhibit high gradients and can be difficult to detect. Thus excessive resolution in certain regions does not necessarily increase the accuracy of the overall solution. Several approaches have been employed for both structured and unstructured grid adaption. The most widely used involve grid point redistribution, local grid point enrichment/derefinement or local modification of the actual flow solver. However, the success of any one of these methods ultimately depends on the feature detection algorithm used to determine solution domain regions which require a fine mesh for their accurate representation. Typically, weight functions are constructed to mimic the local truncation error and may require substantial user input. Most problems of engineering interest involve multi-block grids and widely disparate length scales. Hence, it is desirable that the adaptive grid feature detection algorithm be developed to recognize flow structures of different type as well as differing intensity, and adequately address scaling and normalization across blocks. These weight functions can then be used to construct blending functions for algebraic redistribution, interpolation functions for unstructured grid generation, forcing functions to attract/repel points in an elliptic system, or to trigger local refinement, based upon application of an equidistribution principle. The popularity of solution-adaptive techniques is growing in tandem with unstructured methods. The difficultly of precisely controlling mesh densities and orientations with current unstructured grid generation systems has driven the use of solution-adaptive meshing. Use of derivatives of density or pressure are widely used for construction of such weight functions, and have been proven very successful for inviscid flows with shocks. However, less success has been realized for flowfields with viscous layers, vortices or shocks of disparate strength. It is difficult to maintain the appropriate mesh point spacing in the various regions which require a fine spacing for adequate resolution. Mesh points often migrate from important regions due to refinement of dominant features. An example of this is the well know tendency of adaptive methods to increase the resolution of shocks in the flowfield around airfoils, but in the incorrect location due to inadequate resolution of the stagnation region. This problem has been the motivation for this research.

An interactive multi-block grid generation system

NASA Technical Reports Server (NTRS)

Kao, T. J.; Su, T. Y.; Appleby, Ruth

1992-01-01

A grid generation procedure combining interactive and batch grid generation programs was put together to generate multi-block grids for complex aircraft configurations. The interactive section provides the tools for 3D geometry manipulation, surface grid extraction, boundary domain construction for 3D volume grid generation, and block-block relationships and boundary conditions for flow solvers. The procedure improves the flexibility and quality of grid generation to meet the design/analysis requirements.

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

A new lumped-parameter approach to simulating flow processes in unsaturated dual-porosity media

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

Zimmerman, R.W.; Hadgu, T.; Bodvarsson, G.S.

We have developed a new lumped-parameter dual-porosity approach to simulating unsaturated flow processes in fractured rocks. Fluid flow between the fracture network and the matrix blocks is described by a nonlinear equation that relates the imbibition rate to the local difference in liquid-phase pressure between the fractures and the matrix blocks. This equation is a generalization of the Warren-Root equation, but unlike the Warren-Root equation, is accurate in both the early and late time regimes. The fracture/matrix interflow equation has been incorporated into a computational module, compatible with the TOUGH simulator, to serve as a source/sink term for fracture elements.more » The new approach achieves accuracy comparable to simulations in which the matrix blocks are discretized, but typically requires an order of magnitude less computational time.« less

The efficacy of IntraFlow intraosseous injection as a primary anesthesia technique.

PubMed

Remmers, Todd; Glickman, Gerald; Spears, Robert; He, Jianing

2008-03-01

The purpose of this study was to compare the efficacy of intraosseous injection and inferior alveolar (IA) nerve block in anesthetizing mandibular posterior teeth with irreversible pulpitis. Thirty human subjects were randomly assigned to receive either intraosseous injection using the IntraFlow system (Pro-Dex Inc, Santa Ana, CA) or IA block as the primary anesthesia method. Pulpal anesthesia was evaluated via electric pulp testing at 4-minute intervals for 20 minutes. Two consecutive 80/80 readings were considered successful pulpal anesthesia. Anesthesia success or failure was recorded and groups compared. Intraosseous injection provided successful anesthesia in 13 of 15 subjects (87%). The IA block provided successful anesthesia in 9 of 15 subjects (60%). Although this difference was not statistically significant (p = 0.2148), the results of this preliminary study indicate that the IntraFlow system can be used as the primary anesthesia method in teeth with irreversible pulpitis to achieve predictable pulpal anesthesia.

Heat Flow Budget of the Gulf of California Rift: Preliminary Results of a High Resolution Survey Across the Wagner Basin

NASA Astrophysics Data System (ADS)

Negrete-Aranda, R.; Neumann, F.; Harris, R. N.; Contreras, J.; Gonzalez-Fernandez, A.; Sclater, J. G.

2016-12-01

The thermal regime exerts a primary control on rift dynamics and mode of extension for continental lithosphere. We present three heat-flow profiles across the southern terminus of the Cerro Prieto fault, in the northern Gulf of California. The longest profile is 42 km and has a measurement spacing of 1 km that spans the hanging-wall block (Wagner basin) and the footwall block of that fault. Measurements were taken with a 6.5 m long Fielax, violin-bow probe. Most measurements are of good quality, i.e., the probe fully penetrated sediments and measurements were stable enough to perform reliable inversion for heat flow and thermal properties. However, it was necessary to perform numerous corrections due to environmental phenomena related the copious sedimentation in the area, and seasonal changes in water temperature. Our measurements indicate the total throughput across the central rift and its east shoulder is 15 KW/m per meter of rift length. More important, heat flow values cluster in three distinct spatial groups: (i) heat flow in the well sedimented depocenter of the Wagner basin is approximately 200 mW/m2; (ii) the footwall block heat-flow is approximately 400 mW/m2; and (iii) heat flow across the fault zone is very high, up to 5,000 mW/m2. Our interpretation is that the former value represents the background conductive heat flow in the rift whereas heat flow across the fault represents advective heat transport by hydrothermal fluids. The high heat flow in the footwall block of the Cerro Prieto fault might be result of both conductive and advective heat transfer by fluid seepage from the basin. These data provide evidence that fluids from deep magma bodies transported along faults assist rifting in the northern Gulf of California. We are exploring how fluids may play a role in weakening the lithosphere and help localizing/delocalizing strain along major transforms and numerous normal faults observed in the area.

Statistical scaling of pore-scale Lagrangian velocities in natural porous media.

PubMed

Siena, M; Guadagnini, A; Riva, M; Bijeljic, B; Pereira Nunes, J P; Blunt, M J

2014-08-01

We investigate the scaling behavior of sample statistics of pore-scale Lagrangian velocities in two different rock samples, Bentheimer sandstone and Estaillades limestone. The samples are imaged using x-ray computer tomography with micron-scale resolution. The scaling analysis relies on the study of the way qth-order sample structure functions (statistical moments of order q of absolute increments) of Lagrangian velocities depend on separation distances, or lags, traveled along the mean flow direction. In the sandstone block, sample structure functions of all orders exhibit a power-law scaling within a clearly identifiable intermediate range of lags. Sample structure functions associated with the limestone block display two diverse power-law regimes, which we infer to be related to two overlapping spatially correlated structures. In both rocks and for all orders q, we observe linear relationships between logarithmic structure functions of successive orders at all lags (a phenomenon that is typically known as extended power scaling, or extended self-similarity). The scaling behavior of Lagrangian velocities is compared with the one exhibited by porosity and specific surface area, which constitute two key pore-scale geometric observables. The statistical scaling of the local velocity field reflects the behavior of these geometric observables, with the occurrence of power-law-scaling regimes within the same range of lags for sample structure functions of Lagrangian velocity, porosity, and specific surface area.

Optimization of Blocked Designs in fMRI Studies

ERIC Educational Resources Information Center

Maus, Barbel; van Breukelen, Gerard J. P.; Goebel, Rainer; Berger, Martijn P. F.

2010-01-01

Blocked designs in functional magnetic resonance imaging (fMRI) are useful to localize functional brain areas. A blocked design consists of different blocks of trials of the same stimulus type and is characterized by three factors: the length of blocks, i.e., number of trials per blocks, the ordering of task and rest blocks, and the time between…

Methods for Estimating Withdrawal and Return Flow by Census Block for 2005 and 2020 for New Hampshire

USGS Publications Warehouse

Hayes, Laura; Horn, Marilee A.

2009-01-01

The U.S. Geological Survey, in cooperation with the New Hampshire Department of Environmental Services, estimated the amount of water demand, consumptive use, withdrawal, and return flow for each U.S. Census block in New Hampshire for the years 2005 (current) and 2020. Estimates of domestic, commercial, industrial, irrigation, and other nondomestic water use were derived through the use and innovative integration of several State and Federal databases, and by use of previously developed techniques. The New Hampshire Water Demand database was created as part of this study to store and integrate State of New Hampshire data central to the project. Within the New Hampshire Water Demand database, a lookup table was created to link the State databases and identify water users common to more than one database. The lookup table also allowed identification of withdrawal and return-flow locations of registered and unregistered commercial, industrial, agricultural, and other nondomestic users. Geographic information system data from the State were used in combination with U.S. Census Bureau spatial data to locate and quantify withdrawals and return flow for domestic users in each census block. Analyzing and processing the most recently available data resulted in census-block estimations of 2005 water use. Applying population projections developed by the State to the data sets enabled projection of water use for the year 2020. The results for each census block are stored in the New Hampshire Water Demand database and may be aggregated to larger political areas or watersheds to assess relative hydrologic stress on the basis of current and potential water availability.

Variable High Order Multiblock Overlapping Grid Methods for Mixed Steady and Unsteady Multiscale Viscous Flows

NASA Technical Reports Server (NTRS)

Sjogreen, Bjoern; Yee, H. C.

2007-01-01

Flows containing steady or nearly steady strong shocks in parts of the flow field, and unsteady turbulence with shocklets on other parts of the flow field are difficult to capture accurately and efficiently employing the same numerical scheme even under the multiblock grid or adaptive grid refinement framework. On one hand, sixth-order or higher shock-capturing methods are appropriate for unsteady turbulence with shocklets. On the other hand, lower order shock-capturing methods are more effective for strong steady shocks in terms of convergence. In order to minimize the shortcomings of low order and high order shock-capturing schemes for the subject flows,a multi- block overlapping grid with different orders of accuracy on different blocks is proposed. Test cases to illustrate the performance of the new solver are included.

Knowledge and Processes in Design

DTIC Science & Technology

1992-09-03

Orqanization Name(s) and Address(es). Self-explanatory. Block 16. Price Code. Enter approoriate price Block 8. Performing Organization Report code...NTIS on/y). Number. Enter the unique alphanumerc report number(s) assigned by the organization periorming the report. Blocks 17.-19...statement codings were then organized into larger control-flow structures centered around design components called modules. The general assumption was

United States Air Force Summer Research Program -- 1993 Summer Research Program Final Reports. Volume 11. Arnold Engineering Development Center, Frank J. Seiler Research Laboratory, Wilford Hall Medical Center

DTIC Science & Technology

1993-01-01

external parameters such as airflow, temperature, pressure, etc, are measured. Turbine Engine testing generates massive volumes of data at very high...a form that describes the signal flow graph topology as well as specific parameters of the processing blocks in the diagram. On multiprocessor...provides an interface to the symbolic builder and control functions such that parameters may be set during the build operation that will affect the

Application of blocking diagnosis methods to General Circulation Models. Part I: a novel detection scheme

NASA Astrophysics Data System (ADS)

Barriopedro, D.; García-Herrera, R.; Trigo, R. M.

2010-12-01

This paper aims to provide a new blocking definition with applicability to observations and model simulations. An updated review of previous blocking detection indices is provided and some of their implications and caveats discussed. A novel blocking index is proposed by reconciling two traditional approaches based on anomaly and absolute flows. Blocks are considered from a complementary perspective as a signature in the anomalous height field capable of reversing the meridional jet-based height gradient in the total flow. The method succeeds in identifying 2-D persistent anomalies associated to a weather regime in the total flow with blockage of the westerlies. The new index accounts for the duration, intensity, extension, propagation, and spatial structure of a blocking event. In spite of its increased complexity, the detection efficiency of the method is improved without hampering the computational time. Furthermore, some misleading identification problems and artificial assumptions resulting from previous single blocking indices are avoided with the new approach. The characteristics of blocking for 40 years of reanalysis (1950-1989) over the Northern Hemisphere are described from the perspective of the new definition and compared to those resulting from two standard blocking indices and different critical thresholds. As compared to single approaches, the novel index shows a better agreement with reported proxies of blocking activity, namely climatological regions of simultaneous wave amplification and maximum band-pass filtered height standard deviation. An additional asset of the method is its adaptability to different data sets. As critical thresholds are specific of the data set employed, the method is useful for observations and model simulations of different resolutions, temporal lengths and time variant basic states, optimizing its value as a tool for model validation. Special attention has been paid on the devise of an objective scheme easily applicable to General Circulation Models where observational thresholds may be unsuitable due to the presence of model bias. Part II of this study deals with a specific implementation of this novel method to simulations of the ECHO-G global climate model.

Multi-blocking strategies for the INS3D incompressible Navier-Stokes code

NASA Technical Reports Server (NTRS)

Gatlin, Boyd

1990-01-01

With the continuing development of bigger and faster supercomputers, computational fluid dynamics (CFD) has become a useful tool for real-world engineering design and analysis. However, the number of grid points necessary to resolve realistic flow fields numerically can easily exceed the memory capacity of available computers. In addition, geometric shapes of flow fields, such as those in the Space Shuttle Main Engine (SSME) power head, may be impossible to fill with continuous grids upon which to obtain numerical solutions to the equations of fluid motion. The solution to this dilemma is simply to decompose the computational domain into subblocks of manageable size. Computer codes that are single-block by construction can be modified to handle multiple blocks, but ad-hoc changes in the FORTRAN have to be made for each geometry treated. For engineering design and analysis, what is needed is generalization so that the blocking arrangement can be specified by the user. INS3D is a computer program for the solution of steady, incompressible flow problems. It is used frequently to solve engineering problems in the CFD Branch at Marshall Space Flight Center. INS3D uses an implicit solution algorithm and the concept of artificial compressibility to provide the necessary coupling between the pressure field and the velocity field. The development of generalized multi-block capability in INS3D is described.

Medial approach of ultrasound-guided costoclavicular plexus block and its effects on regional perfussion.

PubMed

Nieuwveld, D; Mojica, V; Herrera, A E; Pomés, J; Prats, A; Sala-Blanch, X

2017-04-01

Ultrasound-guided infraclavicular block in the costoclavicular space located between the clavicle and the first rib, reaches the secondary trunks when they are clustered together and lateral to the axillary artery. This block is most often performed through a lateral approach, the difficulty being finding the coracoid process an obstacle and guiding the needle towards the vessels and pleura. A medial approach, meaning from inside to outside, will avoid these structures. Traditionally the assessment of a successful block is through motor or sensitive responses but a sympathetic fibre block can also be evaluated measuring the changes in humeral artery blood flow, skin temperature and/or perfusion index. To describe the medial approach of the ultrasound-guided costoclavicular block evaluating its development by motor and sensitive response and measurement of sympathetic changes. Description of the technique and administration of 20ml of contrast in a fresh cadaver model, evaluating the distribution with CT-scan and sagittal sections of the anatomic piece. Subsequently in a clinical phase, including 11 patients, we evaluated the establishment of motor, sensitive and sympathetic blocks. We evaluated the sympathetic changes reflected by humeral artery blood flow, skin temperature and distal perfusion index. In the anatomical model the block was conducted without difficulties, showing an adequate periclavicular distribution of the contrast in the CT-scan and in sagittal sections, reaching the interscalenic space as far as the secondary trunks. Successful blocks were observed in 91% of patients after 25minutes. All the parameters reflecting sympathetic block increased significantly. The humeral artery blood flow showed an increase from 108 ± 86 to 188±141ml/min (P=.05), skin temperature from 32.1±2 to 32.8±9°C (P=.03) and perfusion index from 4±3 to 9±5 (P=.003). The medial approach of the ultrasound-guided costoclavicular block is anatomically feasible, with high clinical effectiveness using 20ml of 1.5% mepivacaine. The sympathetic block can be evaluated with all three parameters studied. Copyright © 2016 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Counterrotating prop-fan simulations which feature a relative-motion multiblock grid decomposition enabling arbitrary time-steps

NASA Technical Reports Server (NTRS)

Janus, J. Mark; Whitfield, David L.

1990-01-01

Improvements are presented of a computer algorithm developed for the time-accurate flow analysis of rotating machines. The flow model is a finite volume method utilizing a high-resolution approximate Riemann solver for interface flux definitions. The numerical scheme is a block LU implicit iterative-refinement method which possesses apparent unconditional stability. Multiblock composite gridding is used to orderly partition the field into a specified arrangement of blocks exhibiting varying degrees of similarity. Block-block relative motion is achieved using local grid distortion to reduce grid skewness and accommodate arbitrary time step selection. A general high-order numerical scheme is applied to satisfy the geometric conservation law. An even-blade-count counterrotating unducted fan configuration is chosen for a computational study comparing solutions resulting from altering parameters such as time step size and iteration count. The solutions are compared with measured data.

Study on turbulent flow and heat transfer performance of tubes with internal fins in EGR cooler

NASA Astrophysics Data System (ADS)

Liu, Lin; Ling, Xiang; Peng, Hao

2015-07-01

In this paper, flow and heat transfer performances of the tubes with internal longitudinal fins in Exhaust Gas Recirculation (EGR ) cooler were investigated by three-dimension computation and experiment . Each test tube was a single-pipe structure, without inner tube. Three-dimension computation was performed to determine the thermal characteristics difference between the two kinds of tubes, that is, the tube with an inner solid staff as a blocked structure and the tube without the blocked structure. The effects of fin width and fin height on heat transfer and flow are examined. For proving the validity of numerical method, the calculated results were compared with corresponding experimental data. The tube-side friction factor and heat transfer coefficient were examined. As a result, the maximum deviations between the numerical results and the experimental data are approximately 5.4 % for friction factor and 8.6 % for heat transfer coefficient, respectively. It is found that two types of internally finned tubes enhance significantly heat transfer. The heat transfer of the tube with blocked structure is better, while the pressure drop of the tube without blocked structure is lower. The comprehensive performance of the unblocked tube is better to applied in EGR cooler.

Relations between the structure of storage and the transport of chemical compounds in karstic aquifers

NASA Astrophysics Data System (ADS)

Vaute, L.; Drogue, C.; Garrelly, L.; Ghelfenstein, M.

1997-12-01

Study of the movement of chemical compounds naturally present in the water, or which result from pollution, are examined according to the reservoir structure in karstic aquifers. Structure is represented by a simple geometrical model; slow flow takes place in blocks with a network of low-permeability cracks. The blocks are separated by highly permeable karstic conduits that allow rapid flow, and these form the aquifer drainage system. The karst studied covers 110 km 2. It is fed by an interrupted stream draining a 35 km 2 non-karstic basin, contaminated at the entry to the karst by effluents from a sewage treatment station. The underground water reappears as a resurgence with an annual average flow of approximately 1 m 3 s -1, after an apparent underground course of 8 km in the karst. Several local sources of pollution (effluent from septic tanks) contaminate the underground water during its course. Sixteen measurement operations were performed at 12 water points, between the interrupted stream and the spring. Some sampling points were at drains, and others were in the low-permeability fissured blocks. Comparison at each point of the concentrations of 14 chemical compounds gave the following results: when pollutant discharge occurs in a permeable zone, movement is rapid in the drainage network formed by the karstic conduits, and does not reach the less permeable fissured blocks which are thus protected; however, if discharge is in a low-permeability zone, the flow does not allow rapid movement of the polluted water, and this increases the pollutant concentration at the discharge. This simple pattern can be upset by a reversal of the apparent piezometric gradient between a block and a conduit during floods or pumping; this may reverse flow directions and hence modify the movement of contaminants. The study made it possible to site five boreholes whose positions in the karstic structure were unknown, showing the interest of such an approach for the forecasting of the impact of potential pollution.

Jamming transitions induced by an attraction in pedestrian flow.

PubMed

Kwak, Jaeyoung; Jo, Hang-Hyun; Luttinen, Tapio; Kosonen, Iisakki

2017-08-01

We numerically study jamming transitions in pedestrian flow interacting with an attraction, mostly based on the social force model for pedestrians who can join the attraction. We formulate the joining probability as a function of social influence from others, reflecting that individual choice behavior is likely influenced by others. By controlling pedestrian influx and the social influence parameter, we identify various pedestrian flow patterns. For the bidirectional flow scenario, we observe a transition from the free flow phase to the freezing phase, in which oppositely walking pedestrians reach a complete stop and block each other. On the other hand, a different transition behavior appears in the unidirectional flow scenario, i.e., from the free flow phase to the localized jam phase and then to the extended jam phase. It is also observed that the extended jam phase can end up in freezing phenomena with a certain probability when pedestrian flux is high with strong social influence. This study highlights that attractive interactions between pedestrians and an attraction can trigger jamming transitions by increasing the number of conflicts among pedestrians near the attraction. In order to avoid excessive pedestrian jams, we suggest suppressing the number of conflicts under a certain level by moderating pedestrian influx especially when the social influence is strong.

Jamming transitions induced by an attraction in pedestrian flow

NASA Astrophysics Data System (ADS)

Kwak, Jaeyoung; Jo, Hang-Hyun; Luttinen, Tapio; Kosonen, Iisakki

2017-08-01

We numerically study jamming transitions in pedestrian flow interacting with an attraction, mostly based on the social force model for pedestrians who can join the attraction. We formulate the joining probability as a function of social influence from others, reflecting that individual choice behavior is likely influenced by others. By controlling pedestrian influx and the social influence parameter, we identify various pedestrian flow patterns. For the bidirectional flow scenario, we observe a transition from the free flow phase to the freezing phase, in which oppositely walking pedestrians reach a complete stop and block each other. On the other hand, a different transition behavior appears in the unidirectional flow scenario, i.e., from the free flow phase to the localized jam phase and then to the extended jam phase. It is also observed that the extended jam phase can end up in freezing phenomena with a certain probability when pedestrian flux is high with strong social influence. This study highlights that attractive interactions between pedestrians and an attraction can trigger jamming transitions by increasing the number of conflicts among pedestrians near the attraction. In order to avoid excessive pedestrian jams, we suggest suppressing the number of conflicts under a certain level by moderating pedestrian influx especially when the social influence is strong.

Computing Aerodynamic Performance of a 2D Iced Airfoil: Blocking Topology and Grid Generation

NASA Technical Reports Server (NTRS)

Chi, X.; Zhu, B.; Shih, T. I.-P.; Slater, J. W.; Addy, H. E.; Choo, Yung K.; Lee, Chi-Ming (Technical Monitor)

2002-01-01

The ice accrued on airfoils can have enormously complicated shapes with multiple protruded horns and feathers. In this paper, several blocking topologies are proposed and evaluated on their ability to produce high-quality structured multi-block grid systems. A transition layer grid is introduced to ensure that jaggedness on the ice-surface geometry do not to propagate into the domain. This is important for grid-generation methods based on hyperbolic PDEs (Partial Differential Equations) and algebraic transfinite interpolation. A 'thick' wrap-around grid is introduced to ensure that grid lines clustered next to solid walls do not propagate as streaks of tightly packed grid lines into the interior of the domain along block boundaries. For ice shapes that are not too complicated, a method is presented for generating high-quality single-block grids. To demonstrate the usefulness of the methods developed, grids and CFD solutions were generated for two iced airfoils: the NLF0414 airfoil with and without the 623-ice shape and the B575/767 airfoil with and without the 145m-ice shape. To validate the computations, the computed lift coefficients as a function of angle of attack were compared with available experimental data. The ice shapes and the blocking topologies were prepared by NASA Glenn's SmaggIce software. The grid systems were generated by using a four-boundary method based on Hermite interpolation with controls on clustering, orthogonality next to walls, and C continuity across block boundaries. The flow was modeled by the ensemble-averaged compressible Navier-Stokes equations, closed by the shear-stress transport turbulence model in which the integration is to the wall. All solutions were generated by using the NPARC WIND code.

Nano-structured polymer composites and process for preparing same

DOEpatents

Hillmyer, Marc; Chen, Liang

2013-04-16

A process for preparing a polymer composite that includes reacting (a) a multi-functional monomer and (b) a block copolymer comprising (i) a first block and (ii) a second block that includes a functional group capable of reacting with the multi-functional monomer, to form a crosslinked, nano-structured, bi-continuous composite. The composite includes a continuous matrix phase and a second continuous phase comprising the first block of the block copolymer.

Clogging and transport of driven particles in asymmetric funnel arrays

DOE PAGES

Olson Reichhardt, Cynthia J.; Reichhardt, Charles

2018-05-03

In this paper, we numerically examine the flow and clogging of particles driven through asymmetric funnel arrays when the commensurability ratio of the number of particles per plaquette is varied. The particle-particle interactions are modeled with a soft repulsive potential that could represent vortex flow in type-II superconductors or driven charged colloids. The velocity-force curves for driving in the easy flow direction of the funnels exhibit a single depinning threshold; however, for driving in the hard flow direction, we find that there can be both negative mobility where the velocity decreases with increasing driving force as well as a reentrantmore » pinning effect in which the particles flow at low drives but become pinned at intermediate drives. This reentrant pinning is associated with a transition from smooth one-dimensional flow at low drives to a clogged state at higher drives that occurs when the particles cluster in a small number of plaquettes and block the flow. When the drive is further increased, particle rearrangements occur that cause the clog to break apart. We map out the regimes in which the pinned, flowing, and clogged states appear as a function of plaquette filling and drive. Finally, the clogged states remain robust at finite temperatures but develop intermittent bursts of flow in which a clog temporarily breaks apart but quickly reforms.« less

Clogging and transport of driven particles in asymmetric funnel arrays

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

Olson Reichhardt, Cynthia J.; Reichhardt, Charles

In this paper, we numerically examine the flow and clogging of particles driven through asymmetric funnel arrays when the commensurability ratio of the number of particles per plaquette is varied. The particle-particle interactions are modeled with a soft repulsive potential that could represent vortex flow in type-II superconductors or driven charged colloids. The velocity-force curves for driving in the easy flow direction of the funnels exhibit a single depinning threshold; however, for driving in the hard flow direction, we find that there can be both negative mobility where the velocity decreases with increasing driving force as well as a reentrantmore » pinning effect in which the particles flow at low drives but become pinned at intermediate drives. This reentrant pinning is associated with a transition from smooth one-dimensional flow at low drives to a clogged state at higher drives that occurs when the particles cluster in a small number of plaquettes and block the flow. When the drive is further increased, particle rearrangements occur that cause the clog to break apart. We map out the regimes in which the pinned, flowing, and clogged states appear as a function of plaquette filling and drive. Finally, the clogged states remain robust at finite temperatures but develop intermittent bursts of flow in which a clog temporarily breaks apart but quickly reforms.« less

Evidence for specific annexin I-binding proteins on human monocytes.

PubMed Central

Goulding, N J; Pan, L; Wardwell, K; Guyre, V C; Guyre, P M

1996-01-01

Recombinant human annexin I and a monoclonal antibody specific for this protein (mAb 1B) were used to investigate surface binding of this member of the annexin family of proteins to peripheral blood monocytes. Flow cytometric analysis demonstrated trypsin-sensitive, saturable binding of annexin I to human peripheral blood monocytes but not to admixed lymphocytes. A monoclonal antibody that blocks the anti-phospholipase activity of annexin I also blocked its binding to monocytes. These findings suggest the presence of specific binding sites on monocytes. Furthermore, surface iodination, immunoprecipitation and SDS/PAGE analysis were used to identify two annexin I-binding proteins on the surface of monocytes with molecular masses of 15 kDa and 18 kDa respectively. The identification and characterization of these annexin I-binding molecules should help us to better understand the specific interactions of annexin I with monocytes that lead to down-regulation of pro-inflammatory cell functions. PMID:8687405

Hyperbolic/parabolic development for the GIM-STAR code. [flow fields in supersonic inlets

NASA Technical Reports Server (NTRS)

Spradley, L. W.; Stalnaker, J. F.; Ratliff, A. W.

1980-01-01

Flow fields in supersonic inlet configurations were computed using the eliptic GIM code on the STAR computer. Spillage flow under the lower cowl was calculated to be 33% of the incoming stream. The shock/boundary layer interaction on the upper propulsive surface was computed including separation. All shocks produced by the flow system were captured. Linearized block implicit (LBI) schemes were examined to determine their application to the GIM code. Pure explicit methods have stability limitations and fully implicit schemes are inherently inefficient; however, LBI schemes show promise as an effective compromise. A quasiparabolic version of the GIM code was developed using elastical parabolized Navier-Stokes methods combined with quasitime relaxation. This scheme is referred to as quasiparabolic although it applies equally well to hyperbolic supersonic inviscid flows. Second order windward differences are used in the marching coordinate and either explicit or linear block implicit time relaxation can be incorporated.

Swimming invariant manifolds and the motion of bacteria in a fluid flow

NASA Astrophysics Data System (ADS)

Yoest, Helena; Mitchell, Kevin; Solomon, Tom

2017-11-01

We present experiments on the motion of both wild-type and smooth-swimming bacillus subtilis in a hyperbolic, microfluidic fluid flow. Passive invariant manifolds crossing the fixed point in the flow act as barriers that block inert tracers in the flow. Self-propelled tracers can cross these passive manifolds, but are blocked by and attracted to swimming invariant manifolds (SWIMs) that split from the passive manifolds with larger and larger non-dimensional swimming speed v0 ≡V0 / U , where V0 is the swimming speed in the absence of a flow and U is a characteristic flos speed. We present the theory that predicts these SWIMs for smooth-swimming tracers, along with experiments that we are conducting to test these theories. We also discuss potential effects of rheotaxis and chemotaxis on the phenomena. Supported by NSF Grant DMR-1361881.

40 CFR Table 8 to Subpart Sssss of... - Continuous Compliance with Operating Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... subpart; andii. Reducing the scrubber pressure drop data to 1-hour and 3-hour block averages; and iii.... Reducing the scrubber liquid pH data to 1-hour and 3-hour block averages; and iii. Maintaining the 3-hour... subpart; andii. Reducing the scrubber liquid flow rate data to 1-hour and 3-hour block averages; and iii...

Polymer-based platform for microfluidic systems

DOEpatents

Benett, William [Livermore, CA; Krulevitch, Peter [Pleasanton, CA; Maghribi, Mariam [Livermore, CA; Hamilton, Julie [Tracy, CA; Rose, Klint [Boston, MA; Wang, Amy W [Oakland, CA

2009-10-13

A method of forming a polymer-based microfluidic system platform using network building blocks selected from a set of interconnectable network building blocks, such as wire, pins, blocks, and interconnects. The selected building blocks are interconnectably assembled and fixedly positioned in precise positions in a mold cavity of a mold frame to construct a three-dimensional model construction of a microfluidic flow path network preferably having meso-scale dimensions. A hardenable liquid, such as poly (dimethylsiloxane) is then introduced into the mold cavity and hardened to form a platform structure as well as to mold the microfluidic flow path network having channels, reservoirs and ports. Pre-fabricated elbows, T's and other joints are used to interconnect various building block elements together. After hardening the liquid the building blocks are removed from the platform structure to make available the channels, cavities and ports within the platform structure. Microdevices may be embedded within the cast polymer-based platform, or bonded to the platform structure subsequent to molding, to create an integrated microfluidic system. In this manner, the new microfluidic platform is versatile and capable of quickly generating prototype systems, and could easily be adapted to a manufacturing setting.

Self similarity of two point correlations in wall bounded turbulent flows

NASA Technical Reports Server (NTRS)

Hunt, J. C. R.; Moin, P.; Moser, R. D.; Spalart, P. R.

1987-01-01

The structure of turbulence at a height y from a wall is affected by the local mean shear at y, by the direct effect of the wall on the eddies, and by the action of other eddies close to or far from the wall. Some researchers believe that a single one of these mechanisms is dominant, while others believe that these effects have to be considered together. It is important to understand the relative importance of these effects in order to develop closure models, for example for the dissipation or for the Reynolds stress equation, and to understand the eddy structure of cross correlation functions and other measures. The specific objective was to examine the two point correlation, R sub vv, of the normal velocity component v near the wall in a turbulent channel flow and in a turbulent boundary layer. The preliminary results show that even in the inhomogeneous turbulent boundary layer, the two-point correlation function may have self similar forms. The results also show that the effects of shear and of blocking are equally important in the form of correlation functions for spacing normal to the wall. But for spanwise spacing, it was found that the eddy structure is quire different in these near flows. So any theory for turbulent structure must take both these effects into account.

830 nm laser irradiation induces varicosity formation, reduces mitochondrial membrane potential and blocks fast axonal flow in small and medium diameter rat dorsal root ganglion neurons: implications for the analgesic effects of 830 nm laser.

PubMed

Chow, Roberta T; David, Monique A; Armati, Patricia J

2007-03-01

We report the formation of 830 nm (cw) laser-induced, reversible axonal varicosities, using immunostaining with beta-tubulin, in small and medium diameter, TRPV-1 positive, cultured rat DRG neurons. Laser also induced a progressive and statistically significant decrease (p<0.005) in MMP in mitochondria in and between static axonal varicosities. In cell bodies of the neuron, the decrease in MMP was also statistically significant (p<0.05), but the decrease occurred more slowly. Importantly we also report for the first time that 830 nm (cw) laser blocked fast axonal flow, imaged in real time using confocal laser microscopy and JC-1 as mitotracker. Control neurons in parallel cultures remained unaffected with no varicosity formation and no change in MMP. Mitochondrial movement was continuous and measured along the axons at a rate of 0.8 microm/s (range 0.5-2 microm/s), consistent with fast axonal flow. Photoacceptors in the mitochondrial membrane absorb laser and mediate the transduction of laser energy into electrochemical changes, initiating a secondary cascade of intracellular events. In neurons, this results in a decrease in MMP with a concurrent decrease in available ATP required for nerve function, including maintenance of microtubules and molecular motors, dyneins and kinesins, responsible for fast axonal flow. Laser-induced neural blockade is a consequence of such changes and provide a mechanism for a neural basis of laser-induced pain relief. The repeated application of laser in a clinical setting modulates nociception and reduces pain. The application of laser therapy for chronic pain may provide a non-drug alternative for the management of chronic pain.

Asymmetric Impact of Tropical SST Anomalies on Atmospheric Internal Variability over the North Pacific.

NASA Astrophysics Data System (ADS)

Chen, Wilbur Y.; van den Dool, Huug M.

1997-03-01

A substantial asymmetric impact of tropical Pacific SST anomalies on the internal variability of the extratropical atmosphere is found. A variety of diagnoses is performed to help reveal the dynamical processes leading to the large impact. Thirty-five years of geopotential heights and 29 years of wind fields analyzed operationally at the National Centers for Environmental Prediction (NCEP), formerly the National Meteorological Center, and three sets of 10-yr-long perpetual January integrations run with a low-resolution NCEP global spectral model are investigated in detail for the impact of the SST anomalies on the blocking flows over the North Pacific. The impact on large-scale deep trough flows is also examined.Both the blocking and deep trough flows develop twice as much over the North Pacific during La Niña as during El Niño winters. Consequently, the internal dynamics associated low-frequency variability (LFV), with timescales between 7 and 61 days examined in this study, display distinct characteristics: much larger magnitude for the La Niña than the El Niño winters over the eastern North Pacific, where the LFV is highest in general.The diagnosis of the localized Eliassen-Palm fluxes and their divergence reveals that the high-frequency transient eddies (1-7 days) at high latitudes are effective in forming and maintaining the large-scale blocking flows, while the midlatitude transients are less effective. The mean deformation field over the North Pacific is much more diffluent for the La Niña than the El Niño winters, resulting in more blocking flows being developed and maintained during La Niña by the high-frequency transients over the central North Pacific.In addition to the above dynamical process operating on the high-frequency end of the spectrum, the local barotropic energy conversion between the LFV components and the time-mean flows is also operating and playing a crucial role. The kinetic energy conversion represented by the scalar product between the E vector of the low-frequency components and the deformation D vector of the time-mean flow reveals that, on average, the low-frequency components extract energy from the time-mean flow during La Niña winters while they lose energy to the time-mean flow during El Niño winters. This local barotropic energy conversion on the low-frequency end of the spectrum, together with the forcing of the high-frequency transients on blocking flows on the high-frequency end, explain why there is a large difference in the magnitude of low-frequency variability between the La Niña and the El Niño winters.

The 15 September 1991 pyroclastic flows at Unzen Volcano (Japan): a flow model for associated ash-cloud surges

NASA Astrophysics Data System (ADS)

Fujii, Toshitsugu; Nakada, Setsuya

1999-04-01

Large-scale collapse of a dacite dome in the late afternoon of 15 September 1991 generated a series of pyroclastic-flow events at Unzen Volcano. Pyroclastic flows with a volume of 1×10 6 m 3 (as DRE) descended the northeastern slope of the volcano, changing their courses to the southeast due to topographic control. After they exited a narrow gorge, an ash-cloud surge rushed straight ahead, detaching the main body of the flow that turned and followed the topographic lows to the east. The surge swept the Kita-Kamikoba area, which had been devastated by the previous pyroclastic-flow events, and transported a car as far as 120 m. Following detachment, the surge lost its force after it moved several hundred meters, but maintained a high temperature. The deposits consist of a bottom layer of better-sorted ash (unit 1), a thick layer of block and ash (unit 2), and a thin top layer of fall-out ash (unit 3). Unit 2 overlies unit 1 with an erosional contact. The upper part of unit 2 grades into better-sorted ash. At distal block-and-ash flow deposits, the bottom part of unit 2 also consists of better-sorted ash, and the contact with the unit 1 deposits becomes ambiguous. Video footage of cascading pyroclastic flows during the 1991-1995 eruption, traveling over surfaces without any topographic barriers, revealed that lobes of ash cloud protruded intermittently from the moving head and sides, and that these lobes surged ahead on the ground surface. This fact, together with the inspection by helicopter shortly after the events, suggests that the protruded lobes consisted of better-sorted ash, and resulted in the deposits of unit 1. The highest ash-cloud plume at the Oshigadani valley exit, and the thickest deposition of fall-out ash over Kita-Kamikoba and Ohnokoba, indicate that abundant ash was also produced when the flow passed through a narrow gorge. In the model presented here, the ash clouds from the pyroclastic flows were composed of a basal turbulent current of high concentration (main body), an overriding and intermediate fluidization zone, and an overlying dilute cloud. Release of pressurized gas in lava block pores, due to collisions among blocks and the resulting upward current, caused a zone of fluidization just above the main body. The mixture of gas and ash sorted in the fluidization zone moved ahead and to the side of the main body as a gravitational current, where the ash was deposited as surge deposits. The main body, which had high internal friction and shear near its base, then overran the surge deposits, partially eroding them. When the upward current of gas (fluidization) waned, better-sorted ash suspended in the fluidization zone was deposited on block-and-ash deposits. In the distal places of block-and-ash deposits, unit 2 probably was deposited in non-turbulent fashion without any erosion of the underlying layer (unit 1).

Design methodology: edgeless 3D ASICs with complex in-pixel processing for pixel detectors

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

Fahim Farah, Fahim Farah; Deptuch, Grzegorz W.; Hoff, James R.

The design methodology for the development of 3D integrated edgeless pixel detectors with in-pixel processing using Electronic Design Automation (EDA) tools is presented. A large area 3 tier 3D detector with one sensor layer and two ASIC layers containing one analog and one digital tier, is built for x-ray photon time of arrival measurement and imaging. A full custom analog pixel is 65μm x 65μm. It is connected to a sensor pixel of the same size on one side, and on the other side it has approximately 40 connections to the digital pixel. A 32 x 32 edgeless array withoutmore » any peripheral functional blocks constitutes a sub-chip. The sub-chip is an indivisible unit, which is further arranged in a 6 x 6 array to create the entire 1.248cm x 1.248cm ASIC. Each chip has 720 bump-bond I/O connections, on the back of the digital tier to the ceramic PCB. All the analog tier power and biasing is conveyed through the digital tier from the PCB. The assembly has no peripheral functional blocks, and hence the active area extends to the edge of the detector. This was achieved by using a few flavors of almost identical analog pixels (minimal variation in layout) to allow for peripheral biasing blocks to be placed within pixels. The 1024 pixels within a digital sub-chip array have a variety of full custom, semi-custom and automated timing driven functional blocks placed together. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout. The methodology uses the Cadence design platform, however it is not limited to this tool.« less

Design methodology: edgeless 3D ASICs with complex in-pixel processing for pixel detectors

NASA Astrophysics Data System (ADS)

Fahim, Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

2015-08-01

The design methodology for the development of 3D integrated edgeless pixel detectors with in-pixel processing using Electronic Design Automation (EDA) tools is presented. A large area 3 tier 3D detector with one sensor layer and two ASIC layers containing one analog and one digital tier, is built for x-ray photon time of arrival measurement and imaging. A full custom analog pixel is 65μm x 65μm. It is connected to a sensor pixel of the same size on one side, and on the other side it has approximately 40 connections to the digital pixel. A 32 x 32 edgeless array without any peripheral functional blocks constitutes a sub-chip. The sub-chip is an indivisible unit, which is further arranged in a 6 x 6 array to create the entire 1.248cm x 1.248cm ASIC. Each chip has 720 bump-bond I/O connections, on the back of the digital tier to the ceramic PCB. All the analog tier power and biasing is conveyed through the digital tier from the PCB. The assembly has no peripheral functional blocks, and hence the active area extends to the edge of the detector. This was achieved by using a few flavors of almost identical analog pixels (minimal variation in layout) to allow for peripheral biasing blocks to be placed within pixels. The 1024 pixels within a digital sub-chip array have a variety of full custom, semi-custom and automated timing driven functional blocks placed together. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout. The methodology uses the Cadence design platform, however it is not limited to this tool.

Heat flow, heat generation and crustal thermal structure of the northern block of the South Indian Craton

NASA Astrophysics Data System (ADS)

Gupta, Mohan L.; Sharma, S. R.; Sundar, A.

Heat flow values and heat generation data calculated from the concentration of heat producing radioactive elements, U, Th and K in surface rocks were analyzed. The South Indian Craton according to Drury et al., can be divided into various blocks, separated by late Proterozoic shear belts. The northern block comprises Eastern and Western Dharwar Cratons of Rogers (1986), Naqvi and Rogers (1987) and a part of the South Indian granulite terrain up to a shear system occupying the Palghat-Cauvery low lands. The geothermal data analysis clearly demonstrates that the present thermal characteristics of the above two Archaean terrains of the Indian and Australian Shields are quite similar. Their crustal thermal structures are likely to be similar also.

Heat flow, heat generation and crustal thermal structure of the northern block of the South Indian Craton

NASA Technical Reports Server (NTRS)

Gupta, Mohan L.; Sharma, S. R.; Sundar, A.

1988-01-01

Heat flow values and heat generation data calculated from the concentration of heat producing radioactive elements, U, Th and K in surface rocks were analyzed. The South Indian Craton according to Drury et al., can be divided into various blocks, separated by late Proterozoic shear belts. The northern block comprises Eastern and Western Dharwar Cratons of Rogers (1986), Naqvi and Rogers (1987) and a part of the South Indian granulite terrain up to a shear system occupying the Palghat-Cauvery low lands. The geothermal data analysis clearly demonstrates that the present thermal characteristics of the above two Archaean terrains of the Indian and Australian Shields are quite similar. Their crustal thermal structures are likely to be similar also.

Numerical simulations of block-and-ash flows using the Titan2D flow model: examples from the 2006 eruption of Merapi Volcano, Java, Indonesia

NASA Astrophysics Data System (ADS)

Charbonnier, S. J.; Gertisser, R.

2009-10-01

We present Titan2D simulations of two well-characterized block-and-ash flow (BAF) events of the 2006 eruption of Merapi (Java, Indonesia) that affected the Gendol valley on the volcano’s southern flank and adjacent, densely populated interfluve (non-valley) areas: (1) a single dome-collapse event to the south that generated one of the smaller, post-June 14 flows and (2) a sustained, multiple dome-collapse event, also directed to the south, that produced the largest flows of the 2006 eruption emplaced in the afternoon of June 14. Using spatially varying bed friction angles, Titan2D is capable of reproducing the paths, velocities, runout distance, areas covered and deposited volumes of these flows over highly complex topography. The model results provide the basis for estimating the areas and levels of hazards associated with BAFs generated during relatively short as well as prolonged dome-collapse periods and guidance during future eruptive crises at Merapi.

Saddle-node bifurcation to jammed state for quasi-one-dimensional counter-chemotactic flow.

PubMed

Fujii, Masashi; Awazu, Akinori; Nishimori, Hiraku

2010-07-01

The transition of a counter-chemotactic particle flow from a free-flow state to a jammed state in a quasi-one-dimensional path is investigated. One of the characteristic features of such a flow is that the constituent particles spontaneously form a cluster that blocks the path, called a path-blocking cluster (PBC), and causes a jammed state when the particle density is greater than a threshold value. Near the threshold value, the PBC occasionally collapses on itself to recover the free flow. In other words, the time evolution of the size of the PBC governs the flux of a counter-chemotactic flow. In this Rapid Communication, on the basis of numerical results of a stochastic cellular automata (SCA) model, we introduce a Langevin equation model for the size evolution of the PBC that reproduces the qualitative characteristics of the SCA model. The results suggest that the emergence of the jammed state in a quasi-one-dimensional counterflow is caused by a saddle-node bifurcation.

Membrane-spacer assembly for flow-electrode capacitive deionization

NASA Astrophysics Data System (ADS)

Lee, Ki Sook; Cho, Younghyun; Choo, Ko Yeon; Yang, SeungCheol; Han, Moon Hee; Kim, Dong Kook

2018-03-01

Flow-electrode capacitive deionization (FCDI) is a desalination process designed to overcome the limited desalination capacity of conventional CDI systems due to their fixed electrodes. Such a FCDI cell system is comprised of a current collector, freestanding ion-exchange membrane (IEM), gasket, and spacer for flowing saline water. To simplify the cell system, in this study we combined the membrane and spacer into a single unit, by coating the IEM on a porous ceramic structure that acts as the spacer. The combination of membrane with the porous structure avoids the use of costly freestanding IEM. Furthermore, the FCDI system can be readily scaled up by simply inserting the IEM-coated porous structures in between the channels for flow electrodes. However, coating the IEM on such porous ceramic structures can cause a sudden drop in the treatment capacity, if the coated IEM penetrates the ceramic pores and prevents these pores from acting as saline flow channels. To address this issue, we blocked the larger microscale pores on the outer surface with SiO2 and polymeric multilayers. Thus, the IEM is coated only onto the top surface of the porous structure, while the internal pores remain empty to function as water channels.

High performance fuel element with end seal

DOEpatents

Lee, Gary E.; Zogg, Gordon J.

1987-01-01

A nuclear fuel element comprising an elongate block of refractory material having a generally regular polygonal cross section. The block includes parallel, spaced, first and second end surfaces. The first end surface has a peripheral sealing flange formed thereon while the second end surface has a peripheral sealing recess sized to receive the flange. A plurality of longitudinal first coolant passages are positioned inwardly of the flange and recess. Elongate fuel holes are separate from the coolant passages and disposed inwardly of the flange and the recess. The block is further provided with a plurality of peripheral second coolant passages in general alignment with the flange and the recess for flowing coolant. The block also includes two bypasses for each second passage. One bypass intersects the second passage adjacent to but spaced from the first end surface and intersects a first passage, while the other bypass intersects the second passage adjacent to but spaced from the second end surface and intersects a first passage so that coolant flowing through the second passages enters and exits the block through the associated first passages.

Manpower Planning Models. 5. Optimization Models

DTIC Science & Technology

1975-10-01

aide 11 neceaaary and Identity by block number) Manpower Planning \\ \\ X Modelling Optimization 20. ABS emry and Identity by block number...notation resulting from the previous maximum M. We exploit the probabilistic interpretation of the flow process whenever it eases the exposi - tion

Restoration of Bladder and Bowel Function Using Electrical Stimulation and Block after Spinal Cord Injury

DTIC Science & Technology

2015-10-01

AWARD NUMBER: W81XWH-14-2-0132 TITLE: Restoration of Bladder and Bowel Function Using Electrical Stimulation and Block after Spinal Cord Injury...Sept 2015 4. TITLE AND SUBTITLE Restoration of Bladder and Bowel Function Using Electrical Stimulation and Block after Spinal Cord Injury 5a...evaluate the restoration of bladder and bowel function using electrical stimulation and block after spinal cord injury in human subjects. All staff

Immune responses of mussel hemocyte subpopulations are differentially regulated by enzymes of the PI 3-K, PKC, and ERK kinase families.

PubMed

García-García, Erick; Prado-Alvarez, Maria; Novoa, Beatriz; Figueras, Antonio; Rosales, Carlos

2008-01-01

Various hemocyte cell types have been described in invertebrates, but for most species a functional characterization of different hemocyte cell types is still lacking. In order to characterize some immunological properties of mussel (Mytilus galloprovincialis) hemocytes, cells were separated by flow cytometry and their capacity for phagocytosis, production of reactive oxygen species (ROS), and production of nitric oxide (NO), was examined. Phosphatidylinositol 3-kinase (PI 3-K), protein kinase C (PKC), and extracellular signal-regulated kinase (ERK) inhibitors were also used to biochemically characterize these cell responses. Four morphologically distinct subpopulations, designated R1-R4, were detected. R1, R2, and R3 cells presented different levels of phagocytosis towards zymosan, latex beads, and two bacteria species. Similarly, R1 to R3, but not R4, cells produced ROS, while all subpopulations produced NO, in response to zymosan. Internalization of all phagocytic targets was blocked by PI 3-K inhibition. In addition, internalization of latex particles, but not of bacteria, was partially blocked by PKC or ERK inhibition. Interestingly, phagocytosis of zymosan was impaired by PKC, or ERK inhibitors, only in R2 cells. Zymosan-induced ROS production was blocked by PI 3-K inhibition, but not by PKC, or ERK inhibition. In addition, zymosan-stimulated NO production was affected by PI 3-K inhibition in R1 and R2, but not in R3 or R4 cells. NO production in all cell types was unaffected by PKC inhibition, but ERK inhibition blocked it in R2 cells. These data reveal the existence of profound functional and biochemical differences in mussel hemocytes and indicate that M. galloprovincialis hemocytes are specialized cells fulfilling specific tasks in the context of host defense.

Aeromagnetic study of the midcontinent gravity high of central United States

USGS Publications Warehouse

King, Elizabeth R.; Zietz, Isidore

1971-01-01

A composite map of detailed aeromagnetic surveys over the midcontinent gravity high provides coverage of the 600-mi-long buried belt of mafic rocks of the Keweenawan Series from their outcrop localities in Minnesota and Wisconsin through Iowa and Nebraska. A map of the subsurface extent of the mafic rocks, based on the intricate magnetic patterns, shows that the rocks form a long, semicontinuous block, averaging 40 mi wide and consisting mainly of a sequence of layered flows. This sequence is probably fault-bounded and has been tilted up along the margins, where the linearity of the anomalies indicates steeper dips. The associated clastic rocks, indicated by a smoother magnetic pattern, occur in basins along both sides of the mafic belt and in grabens and a series of axial basins on the upper surface of the block. The well-defined outliers of flows marginal to the main block and the truncation of some of the outermost flow units along a diagonal boundary striking at an angle to them suggest that the present boundaries of the block are postdepositional structural features. The basins and the edges of the block appear to have controlled later, largely vertical movement in the overlying Paleozoic and younger sedimentary cover. Calculated models based on coincident magnetic and detailed gravity profiles along typical cross sections of the midcontinent gravity high show that the block of mafic rocks is steep-sided and as much as several miles thick. The free-air gravity anomaly, which consists of a large positive maximum flanked by minima, averages very close to zero, indicating that this major crustal feature is regionally compensated, although locally each of its components shows a large departure from equilibrium. Remanent magnetization is a primary factor in the interpretation of the magnetic data. Magnetic property studies of Keweenawan mafic rocks in the Lake Superior region show that remanent magnetization may be five times the magnetization induced by the present Earth's field and differs from it radically in direction. This magnetization was acquired before the flows were tilted into their present positions. A computed magnetic profile shows that a trough of flows with such a magnetization and inward-dipping limbs can account for the observed persistent lows along the western edge of the block, the relatively low magnetic values along the axis of the block, and the large positive anomaly along the eastern side of the block. Flows as much as 1 mi thick near the base of the sequence have a remanent magnetization with a nearly opposite polarity. This reverse polarity has been measured on both sides of Lake Superior and is probably also present farther south, particularly in Iowa where the outer units of the block in an area north of Des Moines give rise to a prominent magnetic low. The axis of this long belt of Keweenawan mafic rocks cuts discordantly through the prevailing east-west-trending fabric of the older Precambrian terrane from southern Kansas to Lake Superior. This belt has several major left-lateral offsets, one of which produces a complete hiatus in the vicinity of the 40th parallel where an east-west transcontinental rift or fracture zone has been proposed. The axial basins of clastic rocks are outlined by linear magnetic anomalies and show a concordant relation to the structure of the mafic flows. These basins are oriented at an angle to the main axis, suggesting that the entire feature originated as a major rift composed of a series of short, linear, en echelon segments with offsets similar to the transform faults characterizing the present mid-ocean rift system. This midcontinent rift may well have been part of a Keweenawan global rift system with initial offsets consisting of transform faults along pre-existing fractures, but apparently it never fully developed laterally into an ocean basin, and the upwelling mafic material was localized along a relatively narrow belt.

Numerical analysis of hypersonic turbulent film cooling flows

NASA Technical Reports Server (NTRS)

Chen, Y. S.; Chen, C. P.; Wei, H.

1992-01-01

As a building block, numerical capabilities for predicting heat flux and turbulent flowfields of hypersonic vehicles require extensive model validations. Computational procedures for calculating turbulent flows and heat fluxes for supersonic film cooling with parallel slot injections are described in this study. Two injectant mass flow rates with matched and unmatched pressure conditions using the database of Holden et al. (1990) are considered. To avoid uncertainties associated with the boundary conditions in testing turbulence models, detailed three-dimensional flowfields of the injection nozzle were calculated. Two computational fluid dynamics codes, GASP and FDNS, with the algebraic Baldwin-Lomax and k-epsilon models with compressibility corrections were used. It was found that the B-L model which resolves near-wall viscous sublayer is very sensitive to the inlet boundary conditions at the nozzle exit face. The k-epsilon models with improved wall functions are less sensitive to the inlet boundary conditions. The testings show that compressibility corrections are necessary for the k-epsilon model to realistically predict the heat fluxes of the hypersonic film cooling problems.

An implicit time-marching method for studying unsteady flow with massive separation

NASA Technical Reports Server (NTRS)

Osswald, G. A.; Ghia, K. N.; Chia, U.

1985-01-01

A fully implicit time-marching method is developed such that all spatial derivatives are approximated using central differences, but no use is made of any artificial dissipation. The numerical method solves the discretized equations using Alternating Direction Implicit-Block Gaussian Elimination technique. The method is implemented in the unsteady analysis, which solves the incompressible Navier-Stokes equations in terms of vorticity and stream function in generalized orthogonal coordinates. A clustered conformal C-grid is employed, and every effort is made to resolve the various length scales in the flow problem. The metric discontinuity at the branch-cut is treated appropriately using analytic continuation. Introduction of the BGE reordering permits implicit treatment of the branch cut in the numerical method. The vorticity singularity at the cusped trailing edge is also appropriately treated. This accurate and efficient implicit method is used to study flow at Re = 1000, past a 12-percent thick symmetric Joukowski airfoil at high angle of attack 30 and 53 deg.

Elucidation of the critical epitope of an anti-EGFR monoclonal antibody EMab-134.

PubMed

Kaneko, Mika K; Yamada, Shinji; Itai, Shunsuke; Chang, Yao-Wen; Nakamura, Takuro; Yanaka, Miyuki; Kato, Yukinari

2018-07-01

The epidermal growth factor receptor (EGFR) is a type-1 transmembrane receptor tyrosine kinase, which activates the downstream signaling cascades in many tumors, such as oral and lung cancers. We previously developed EMab-134, a novel anti-EGFR monoclonal antibody (mAb), which reacts with endogenous EGFR-expressing cancer cell lines and normal cells independent of glycosylation in Western blotting, flow cytometry, and immunohistochemical analysis. EMab-134 showed very high sensitivity (94.7%) to oral squamous cell carcinomas in immunohistochemical analysis. In this study, we performed enzyme-linked immunosorbent assay (ELISA), flow cytometry, and immunohistochemical analysis to determine the epitope of EMab-134. A blocking peptide (375-394 amino acids of EGFR) neutralized the EMab-134 reaction against oral cancer cells in flow cytometry and immunohistochemistry. The minimum epitope of EMab-134 was found to be the 377- RGDSFTHTPP -386 sequence. Our findings can be applied for the production of more functional anti-EGFR mAbs that in turn can be used for antitumor treatments.

Determination of critical epitope of PcMab-47 against human podocalyxin.

PubMed

Itai, Shunsuke; Yamada, Shinji; Kaneko, Mika K; Kato, Yukinari

2018-07-01

Podocalyxin (PODXL) is a type I transmembrane protein, which is highly glycosylated. PODXL is expressed in some types of human cancer tissues including oral, breast, and lung cancer tissues and may promote tumor growth, invasion, and metastasis. We previously produced PcMab-47, a novel anti-PODXL monoclonal antibody (mAb) which reacts with endogenous PODXL-expressing cancer cell lines and normal cells independently of glycosylation in Western blot, flow cytometry, and immunohistochemical analysis. In this study, we used enzyme-linked immunosorbent assay (ELISA), flow cytometry, and immunohistochemical analysis to determine the epitope of PcMab-47. The minimum epitope of PcMab-47 was found to be Asp207, His208, Leu209, and Met210. A blocking peptide containing this minimum epitope completely neutralized PcMab-47 reaction against oral cancer cells by flow cytometry and immunohistochemical analysis. These findings could lead to the production of more functional anti-PODXL mAbs, which are advantageous for antitumor activities.

Regulation of DNA synthesis and the cell cycle in human prostate cancer cells and lymphocytes by ovine uterine serpin

PubMed Central

Padua, Maria B; Hansen, Peter J

2008-01-01

Background Uterine serpins are members of the serine proteinase inhibitor superfamily. Like some other serpins, these proteins do not appear to be functional proteinase inhibitors. The most studied member of the group, ovine uterine serpin (OvUS), inhibits proliferation of several cell types including activated lymphocytes, bovine preimplantation embryos, and cell lines for lymphoma, canine primary osteosarcoma and human prostate cancer (PC-3) cells. The goal for the present study was to evaluate the mechanism by which OvUS inhibits cell proliferation. In particular, it was tested whether inhibition of DNA synthesis in PC-3 cells involves cytotoxic actions of OvUS or the induction of apoptosis. The effect of OvUS in the production of the autocrine and angiogenic cytokine interleukin (IL)-8 by PC-3 cells was also determined. Finally, it was tested whether OvUS blocks specific steps in the cell cycle using both PC-3 cells and lymphocytes. Results Recombinant OvUS blocked proliferation of PC-3 cells at concentrations as low as 8 μg/ml as determined by measurements of [3H]thymidine incorporation or ATP content per well. Treatment of PC-3 cells with OvUS did not cause cytotoxicity or apoptosis or alter interleukin-8 secretion into medium. Results from flow cytometry experiments showed that OvUS blocked the entry of PC-3 cells into S phase and the exit from G2/M phase. In addition, OvUS blocked entry of lymphocytes into S phase following activation of proliferation with phytohemagglutinin. Conclusion Results indicate that OvUS acts to block cell proliferation through disruption of the cell cycle dynamics rather than induction of cytotoxicity or apoptosis. The finding that OvUS can regulate cell proliferation makes this one of only a few serpins that function to inhibit cell growth. PMID:18218135

Functional morphology and patterns of blood flow in the heart of Python regius.

PubMed

Starck, J Matthias

2009-06-01

Brightness-modulated ultrasonography, continuous-wave Doppler, and pulsed-wave Doppler-echocardiography were used to analyze the functional morphology of the undisturbed heart of ball pythons. In particular, the action of the muscular ridge and the atrio-ventricular valves are key features to understand how patterns of blood flow emerge from structures directing blood into the various chambers of the heart. A step-by-step image analysis of echocardiographs shows that during ventricular diastole, the atrio-ventricular valves block the interventricular canals so that blood from the right atrium first fills the cavum venosum, and blood from the left atrium fills the cavum arteriosum. During diastole, blood from the cavum venosum crosses the muscular ridge into the cavum pulmonale. During middle to late systole the muscular ridge closes, thus prohibiting further blood flow into the cavum pulmonale. At the same time, the atrio-ventricular valves open the interventricular canal and allow blood from the cavum arteriosum to flow into the cavum venosum. In the late phase of ventricular systole, all blood from the cavum pulmonale is pressed into the pulmonary trunk; all blood from the cavum venosum is pressed into both aortas. Quantitative measures of blood flow volume showed that resting snakes bypass the pulmonary circulation and shunt about twice the blood volume into the systemic circulation as into the pulmonary circulation. When digesting, the oxygen demand of snakes increased tremendously. This is associated with shunting more blood into the pulmonary circulation. The results of this study allow the presentation of a detailed functional model of the python heart. They are also the basis for a functional hypothesis of how shunting is achieved. Further, it was shown that shunting is an active regulation process in response to changing demands of the organism (here, oxygen demand). Finally, the results of this study support earlier reports about a dual pressure circulation in Python regius.

Cluster analysis of multiple planetary flow regimes

NASA Technical Reports Server (NTRS)

Mo, Kingtse; Ghil, Michael

1987-01-01

A modified cluster analysis method was developed to identify spatial patterns of planetary flow regimes, and to study transitions between them. This method was applied first to a simple deterministic model and second to Northern Hemisphere (NH) 500 mb data. The dynamical model is governed by the fully-nonlinear, equivalent-barotropic vorticity equation on the sphere. Clusters of point in the model's phase space are associated with either a few persistent or with many transient events. Two stationary clusters have patterns similar to unstable stationary model solutions, zonal, or blocked. Transient clusters of wave trains serve as way stations between the stationary ones. For the NH data, cluster analysis was performed in the subspace of the first seven empirical orthogonal functions (EOFs). Stationary clusters are found in the low-frequency band of more than 10 days, and transient clusters in the bandpass frequency window between 2.5 and 6 days. In the low-frequency band three pairs of clusters determine, respectively, EOFs 1, 2, and 3. They exhibit well-known regional features, such as blocking, the Pacific/North American (PNA) pattern and wave trains. Both model and low-pass data show strong bimodality. Clusters in the bandpass window show wave-train patterns in the two jet exit regions. They are related, as in the model, to transitions between stationary clusters.

Model Experiment on the Temporary Closure of a Breached Bank

NASA Astrophysics Data System (ADS)

Shimada, T.; Maeda, S.; Nakashima, Y.

2016-12-01

In recent years, the possibility of river bank failures has been rising due to increased occurrences of floods from localized torrential downpours and typhoons. To mitigate bank failure damage, we made an experiment to simulate the flood discharge reduction effect of a temporary closure at an opening in a breached bank. A scale river model was used. A bank was made and then breached. Then, model blocks were placed to close the breach, to observe the flood discharge reduction afforded by the closure. We assumed that the blocks would be placed by a crane or from a helicopter, so we placed the model blocks accordingly. Regardless of the placement method, the flood discharge reduction was about 20% when about 50% of the breach was closed by the placement of blocks starting from the upstream-most portion of the breach. That result was because the water flow hit the tip of the placed closure, scoured the bed near the tip, and lowered the bed at the remaining part of the breach opening, after which the area where water flows out did not decrease at the same rate as the rate of longitudinal closure for the breach. In addition, with each successive length of breach closure, the required number of blocks increased and the closure progress decreased, because of the bed degradation. The results show that it is possible to reduce the flood flow from a bank breach effectively while closing the opening by taking measures to reduce bed scouring near the breach.

Quantifying the Interplay of Natural Organic Matter with Environmental Factors on Nanoparticle Transport in Porous Media

NASA Astrophysics Data System (ADS)

Yang, X.; von der Kammer, F.; Wiesner, M.; Yang, Y.; Hofmann, T.

2016-12-01

Humic acid (HA) is widespread in environment and may interfere with nanoparticle transport in porous media. Quantification of the HA's influence is challenging due to the heterogeneous natural of the organic compounds. Through a series of laboratory and modeling studies, we explored (1) the differential mechanisms operated by the sediment - and solution-phase HA in controlling particle transport; (2) the interplay of the HA with several important environmental factors including solution pH, ionic strength (IS), flow rate, organic & particle concentration, and particle size; (3) modeling tools to quantify the above identified influential mechanisms. Study results suggest that site blocking is the main effect imposed by sediment-phase HA on nanoparticle transport while competitive deposition (with nanoparticles) and continuous site blocking occur simultaneously for the solution-phase HA. Solution pH and IS jointly control the HA's blocking efficiency by varying the adsorbed organic conformation. Conversely, the effect of the adsorbed organic concentration appeared to be insignificant. In addition to the chemical parameters, physical parameters like particle size and flow rate also impact on the organic blockage: the blocking efficiency was stronger on larger particles than on smaller ones; increasing flow rate magnifies the HA's blocking efficiency on larger particles but had insignificant impact on smaller ones. Those mechanistic investigations were supported by a quantification approach and a mathematical model developed in those studies. These results can improve the understanding on particle mobility in heterogeneous natural porous media.

Documentation: Motivation and training or automation

NASA Technical Reports Server (NTRS)

Mouton, M. L.

1970-01-01

The road blocks and mental blocks in areas where automation is not taking care of basic documentation problems are discussed. Original project documentation, documentation for project maintenance, and comparison of preliminary and final documentation are described. The use of flow charts is also mentioned.

Application of a multi-block CFD code to investigate the impact of geometry modeling on centrifugal compressor flow field predictions

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

Hathaway, M.D.; Wood, J.R.

1997-10-01

CFD codes capable of utilizing multi-block grids provide the capability to analyze the complete geometry of centrifugal compressors. Attendant with this increased capability is potentially increased grid setup time and more computational overhead with the resultant increase in wall clock time to obtain a solution. If the increase in difficulty of obtaining a solution significantly improves the solution from that obtained by modeling the features of the tip clearance flow or the typical bluntness of a centrifugal compressor`s trailing edge, then the additional burden is worthwhile. However, if the additional information obtained is of marginal use, then modeling of certainmore » features of the geometry may provide reasonable solutions for designers to make comparative choices when pursuing a new design. In this spirit a sequence of grids were generated to study the relative importance of modeling versus detailed gridding of the tip gap and blunt trailing edge regions of the NASA large low-speed centrifugal compressor for which there is considerable detailed internal laser anemometry data available for comparison. The results indicate: (1) There is no significant difference in predicted tip clearance mass flow rate whether the tip gap is gridded or modeled. (2) Gridding rather than modeling the trailing edge results in better predictions of some flow details downstream of the impeller, but otherwise appears to offer no great benefits. (3) The pitchwise variation of absolute flow angle decreases rapidly up to 8% impeller radius ratio and much more slowly thereafter. Although some improvements in prediction of flow field details are realized as a result of analyzing the actual geometry there is no clear consensus that any of the grids investigated produced superior results in every case when compared to the measurements. However, if a multi-block code is available, it should be used, as it has the propensity for enabling better predictions than a single block code.« less

Needle detection in ultrasound using the spectral properties of the displacement field: a feasibility study

NASA Astrophysics Data System (ADS)

Beigi, Parmida; Salcudean, Tim; Rohling, Robert; Lessoway, Victoria A.; Ng, Gary C.

2015-03-01

This paper presents a new needle detection technique for ultrasound guided interventions based on the spectral properties of small displacements arising from hand tremour or intentional motion. In a block-based approach, the displacement map is computed for each block of interest versus a reference frame, using an optical flow technique. To compute the flow parameters, the Lucas-Kanade approach is used in a multiresolution and regularized form. A least-squares fit is used to estimate the flow parameters from the overdetermined system of spatial and temporal gradients. Lateral and axial components of the displacement are obtained for each block of interest at consecutive frames. Magnitude-squared spectral coherency is derived between the median displacements of the reference block and each block of interest, to determine the spectral correlation. In vivo images were obtained from the tissue near the abdominal aorta to capture the extreme intrinsic body motion and insertion images were captured from a tissue-mimicking agar phantom. According to the analysis, both the involuntary and intentional movement of the needle produces coherent displacement with respect to a reference window near the insertion site. Intrinsic body motion also produces coherent displacement with respect to a reference window in the tissue; however, the coherency spectra of intrinsic and needle motion are distinguishable spectrally. Blocks with high spectral coherency at high frequencies are selected, estimating a channel for needle trajectory. The needle trajectory is detected from locally thresholded absolute displacement map within the initial estimate. Experimental results show the RMS localization accuracy of 1:0 mm, 0:7 mm, and 0:5 mm for hand tremour, vibrational and rotational needle movements, respectively.

Acquired heart block: a possible complication of patent ductus arteriosus in a preterm infant.

PubMed

Grasser, Monika; Döhlemann, Christoph; Mittal, Rashmi; Till, Holger; Dietz, Hans-Georg; Münch, Georg; Holzinger, Andreas

2008-01-01

A large patent ductus arteriosus (PDA) is a frequently encountered clinical problem in extremely low birth weight (ELBW) infants. It leads to an increased pulmonary blood flow and in a decreased or reversed diastolic flow in the systemic circulation, resulting in complications. Here we report a possible complication of PDA not previously published. On day 8 of life, a male ELBW infant (birth weight 650 g) born at a gestational age of 23 weeks and 3 days developed an atrioventricular block (AV block). The heart rate dropped from 168/min to 90/min, and the ECG showed a Wenckebach second-degree AV block and intraventricular conduction disturbances. Echocardiography demonstrated a PDA with a large left-to-right shunt and large left atrium and left ventricle with high contractility. Within several minutes after surgical closure of the PDA, the heart rate increased, and after 30 min the AV block had improved to a 1:1 conduction ratio. Echocardiography after 2 h revealed a significant decrease of the left ventricular and atrial dimensions. Within 12 h, the AV block completely reversed together with the intraventricular conduction disturbances. We suggest that PDA with a large left-to-right shunt and left ventricular volume overload may lead to an AV block in an ELBW infant. Surgical closure of the PDA may be indicated. (c) 2007 S. Karger AG, Basel.

Cluster analysis of multiple planetary flow regimes

NASA Technical Reports Server (NTRS)

Mo, Kingtse; Ghil, Michael

1988-01-01

A modified cluster analysis method developed for the classification of quasi-stationary events into a few planetary flow regimes and for the examination of transitions between these regimes is described. The method was applied first to a simple deterministic model and then to a 500-mbar data set for Northern Hemisphere (NH), for which cluster analysis was carried out in the subspace of the first seven empirical orthogonal functions (EOFs). Stationary clusters were found in the low-frequency band of more than 10 days, while transient clusters were found in the band-pass frequency window between 2.5 and 6 days. In the low-frequency band, three pairs of clusters determined EOFs 1, 2, and 3, respectively; they exhibited well-known regional features, such as blocking, the Pacific/North American pattern, and wave trains. Both model and low-pass data exhibited strong bimodality.

B-spline Method in Fluid Dynamics

NASA Technical Reports Server (NTRS)

Botella, Olivier; Shariff, Karim; Mansour, Nagi N. (Technical Monitor)

2001-01-01

B-spline functions are bases for piecewise polynomials that possess attractive properties for complex flow simulations : they have compact support, provide a straightforward handling of boundary conditions and grid nonuniformities, and yield numerical schemes with high resolving power, where the order of accuracy is a mere input parameter. This paper reviews the progress made on the development and application of B-spline numerical methods to computational fluid dynamics problems. Basic B-spline approximation properties is investigated, and their relationship with conventional numerical methods is reviewed. Some fundamental developments towards efficient complex geometry spline methods are covered, such as local interpolation methods, fast solution algorithms on cartesian grid, non-conformal block-structured discretization, formulation of spline bases of higher continuity over triangulation, and treatment of pressure oscillations in Navier-Stokes equations. Application of some of these techniques to the computation of viscous incompressible flows is presented.

Technology Implementation and Workarounds in the Nursing Home

PubMed Central

Vogelsmeier, Amy A.; Halbesleben, Jonathon R.B.; Scott-Cawiezell, Jill R.

2008-01-01

Objective This study sought to explore the relationship of workarounds related to the implementation of an electronic medication administration record and medication safety practices in five Midwestern nursing homes. Design As a part of a larger study, this qualitative evaluation was conducted to identify workarounds associated with the implementation of an electronic medication administration record. Data were collected using multimethods including direct observation, process mapping, key informant interviews, and review of field notes from medication safety team meetings. Measurements Open and axial coding techniques were used to identify and categorize types of workarounds in relation to work flow blocks. Results Workarounds presented in two distinct patterns, those related to work flow blocks introduced by technology and those related to organizational processes not reengineered to effectively integrate with the technology. Workarounds such as safety alert overrides and shortcuts to documentation resulted from first-order problem solving of immediate blocks. Nursing home staff as individuals frequently used first-order problem solving instead of the more sophisticated second-order problem solving approach used by the medication safety team. Conclusion This study provides important practical examples of how nursing home staff work around work flow blocks encountered during the implementation of technology. Understanding these workarounds as a means of first-order problem solving is an important consideration to understanding risk to medication safety. PMID:17947626

Evaluation of geophysical mass flow models using the 2006 block-and-ash flows of Merapi Volcano, Java, Indonesia: Towards a short-term hazard assessment tool

NASA Astrophysics Data System (ADS)

Charbonnier, S. J.; Gertisser, R.

2012-06-01

The dynamics and depositional processes associated with block-and-ash flows (BAFs) are most commonly inferred to be a function of granular or inertial grain flow, similar to debris flows and cold rock avalanches. Existing geophysical mass flow models are either based on frictional (Mohr-Coulomb) behavior (the Titan2D model developed at the State University of New York at Buffalo, USA) or another rheological law (i.e., a constant retarding stress), eventually adding some viscous and turbulent components (the VolcFlow model developed at the Laboratoire Magmas et Volcans, Clermont-Ferrand, France). The 2006 BAFs of Merapi present a rare opportunity to test these two well-established models against a well-constrained field example. Integration of high-resolution field-based data into numerical simulations allows the validity of these models to be tested and rapid quantification of best-fit input parameters. We first show that with the incorporation of spatially varying bed friction angles, Titan2D is capable of reproducing the paths, runout distances, areas covered and deposited volumes of the 2006 Merapi flows over highly complex topography. However, some discrepancies with field data are noted and the velocity and travel time of the flows do not match entirely. Using a single free parameter (a constant retarding stress), simulations obtained with the VolcFlow model also reproduce the morphology and distribution of the natural deposits as well as the time of emplacement and velocities of the flows. The results suggest that the performance of these models in simulating actual events is critically dependent on: (1) the calibration of the model by using extensive field-based data such as deposit distribution, and processes of flow generation, transport and deposition; (2) the incorporation of a suitable numerical topographic dataset (i.e., high-resolution digital elevation model), and (3) the choice of input parameters, such as location and volume of the initial pile of material and source characteristics (single or multiple dome-collapse, dome-collapse duration and total volume of collapsed material). Sensitivity analyses and inundation maps based on the probability of impact were used to produce a suite of potentially inundated areas from future gravitational dome-collapse events affecting the Gendol valley and adjacent areas on the southern flank of the volcano. Our results provide the basis for defining hazard zonations of key areas at risk from BAFs which will be generated during future comparable eruptions at Merapi.

Debris flow reconstruction - geomorphologic and numerical approach. A case study from the Selvetta event in Valtellina, Italy, July 2008

NASA Astrophysics Data System (ADS)

Blahut, J.; Luna, B. Quan; Akbas, S. O.; van Westen, C. J.

2009-04-01

On Sunday morning of 13th July 2008, after more than two days of intense rainfall, several debris and mud flows were released in the central part of Valtellina valley between Morbegno and Berbenno. One of the largest debris flows occurred in Selvetta, a fraction of Colorina municipality. The debris flow event was reconstructed after extensive field work and interviews with local inhabitants and civil protection teams. At first several rock blocks about 2 m3 in size fell down from the direction of the torrent. The blocks were followed by a wave of debris and mud that immediately destroyed one building and caused damage to other nine houses. A stream flow following the debris flow consisting of fine mud with high water content that partially washed away the accumulation of deposits from the debris phase could also be distinguished. Geomorphologic investigations allowed identification of five main sections of the flow: 1) the proper scarp; 2) path in the forested area; 3) path on the alpine meadows; 4) accelerating section; 5) accumulation area. The initiation area of the flow is situated at 1760 m. a.s.l. (1480 m above the deposition zone) in a coniferous forest. The proper scarp consisted of an area of approximately 20 m2 in size, and a height of about 0.8 m. The final volume of the debris was estimated by field mapping to be between 12 000 and 15 000 m3. It was observed that erosion and entrainment played an important role in the development of the debris flow. The Selvetta event was modelled with the FLO2D program. FLO2D is an Eulerian formulation with a finite differences numerical scheme that requires the specification of an input hydrograph. The internal stresses are isotropic and the basal shear stresses are calculated using a quadratic model. Entrainment was modeled at each section of the flow, and different hydrographs were produced in agreement with the behavior of the debris flow during its course. The significance of calculated values of pressure and velocity were investigated in terms of the resulting damage to the affected buildings. The physical damage was quantified for each affected structure within the context of physical vulnerability, which is defined as the ratio between the monetary loss and the reconstruction value. Two different empirical vulnerability curves were obtained, which are functions of debris flow velocity and pressure, respectively.

Nanoporous polysulfone membranes via a degradable block copolymer precursor for redox flow batteries

DOE PAGES

Gindt, Brandon P.; Abebe, Daniel G.; Tang, Zhijiang J.; ...

2016-02-16

In this study, nanoporous polysulfone (PSU) membranes were fabricated via post-hydrolysis of polylactide (PLA) from PLA–PSU–PLA triblock copolymer membranes. The PSU scaffold was thermally crosslinked before sacrificing PLA blocks. The resulting nanopore surface was chemically modified with sulfonic acid moieties. The membranes were analyzed and evaluated as separators for vanadium redox flow batteries. Nanoporous PSU membranes prepared by this new method and further chemically modified to a slight degree exhibited unique behavior with respect to their ionic conductivity when exposed to solutions of increasing acid concentration.

Magma mixing during caldera forming eruptions

NASA Astrophysics Data System (ADS)

Kennedy, B.; Jellinek, M.; Stix, J.

2006-12-01

During explosive caldera-forming eruptions magma erupts through a ring dyke. Flow is driven, in part, by foundering of a magma chamber roof into underlying buoyant magma. One intriguing and poorly understood characteristic of deposits from calderas is that bulk ignimbrite, pumices, and crystals can show complex stratigraphic zonation. We propose that zonation patterns can be explained by different, and temporally evolving subsidence styles, and that the geometry imposed by subsidence can affect flow and cause mixing in the chamber and ring dyke. We use two series of laboratory experiments to investigate aspects of the mixing properties of flow in the chamber and ring dike during caldera collapse. In the first series, cylindrical blocks of height, h, and diameter, d, are released into circular analog magma chambers of diameter D and height H, containing buoyant fluids with viscosities that we vary. Subsidence occurs as a result of flow through the annular gap (ring dike) between the block and the wall of the surrounding tank of width, w = D-d. Three dimensionless parameters characterize the nature and evolution of the subsidence, and the resulting flow: A Reynolds number, Re, a tilt number, T = w/h and a subsidence number, S = w/H. Whereas Re indicates the importance of inertia for flow and mixing, T and S are geometric parameters that govern the extent of roof tilting, the spatial variation in w during collapse and the wavelength and structure of fluid motions. On the basis of field observations and theoretical arguments we fix T ≍ 0.14 and characterize subsidence and the corresponding flow over a wide range of Re - S parameter space appropriate to silicic caldera systems. Where S < 2 and Re < 103 the roof can rotate or tilt as it sinks and a spectrum of fluid mechanical behavior within the ring dike are observed. The combination of roof rotation and tilting drives unsteady, 3D overturning motions within the ring dike that are inferred to cause extensive mixing. In the absence of tilting and rotation flow is quasi-steady, there is negligible overturning and mixing. Where S > 2 and Re < 10^1 there is a "locking regime" in which the roof the roof rotates as it sinks but does not settle to the floor. The resulting flow leads to little overturning and mixing. Where S > 2 and Re > 10^1 the roof block settles with negligible tilting. Unsteady laminar overturning (Re < 102) and turbulent motions (Re > 103) produce extensive mixing in the ring dike. In a second series of experiments, motivated by the "piecemeal" collapse of many calderas, we investigate additional effects arising in the presence of two blocks. In contrast to the single-block case, the relative motions of the blocks cause extensive overturning and mixing in the chamber as well as the ring dike. Our experimental results are applied to understand the subsidence behavior and the mixing properties of a number of natural cases. Our work suggests that during most caldera-forming eruptions mixing is an inevitable consequence of synchronous eruption and subsidence. In addition, extensive mechanical mixing within the ring dike can explain the cumulate and mingled textures characteristic of many ring dikes.

Diastolic mitral and tricuspid regurgitation by Doppler echocardiography in patients with atrioventricular block: new insight into the mechanism of atrioventricular valve closure.

PubMed

Schnittger, I; Appleton, C P; Hatle, L K; Popp, R L

1988-01-01

The purpose of this study was to prospectively determine the incidence of diastolic mitral and tricuspid regurgitation in atrioventricular (AV) block using Doppler echocardiography. The temporal relation between mitral and tricuspid diastolic insufficiency and the diastolic murmur recorded in patients with complete heart block was also investigated. Twenty-two consecutive patients with AV block (referred to the Echo-Doppler laboratory for routine clinical studies), aged 18 to 87 years, were enrolled in the study. Eleven patients had third degree AV block and a ventricular-inhibited (VVI) pacemaker, two patients had second degree AV block, seven patients had first degree AV block, one patient had blocked premature atrial complexes and one patient had atrial flutter with 4:1 AV block. Diastolic mitral regurgitation was detected in 20 patients, and diastolic tricuspid regurgitation in 21. A mid-diastolic murmur was detected in all patients except in the three youngest. The murmur occurred before diastolic regurgitation and coincided with peak forward flow through the AV valve after atrial contraction. M-mode mitral valve echocardiograms obtained in nine patients demonstrated near closure of some portions of the mitral valve after atrial contraction. Effective closure of the valve, however, did not occur unless ventricular systole supervened. In conclusion, diastolic mitral and tricuspid regurgitation are almost universally present in patients with AV block and are associated with a diastolic murmur. The murmur coincides with forward AV valve flow. Diastolic regurgitation is silent. Effective AV valve closure is not established until ventricular systole occurs, as demonstrated by M-mode echocardiographic recording of the mitral valve.

Leveraging pattern matching to solve SRAM verification challenges at advanced nodes

NASA Astrophysics Data System (ADS)

Kan, Huan; Huang, Lucas; Yang, Legender; Zou, Elaine; Wan, Qijian; Du, Chunshan; Hu, Xinyi; Liu, Zhengfang; Zhu, Yu; Zhang, Recoo; Huang, Elven; Muirhead, Jonathan

2018-03-01

Memory is a critical component in today's system-on-chip (SoC) designs. Static random-access memory (SRAM) blocks are assembled by combining intellectual property (IP) blocks that come from SRAM libraries developed and certified by the foundries for both functionality and a specific process node. Customers place these SRAM IP in their designs, adjusting as necessary to achieve DRC-clean results. However, any changes a customer makes to these SRAM IP during implementation, whether intentionally or in error, can impact yield and functionality. Physical verification of SRAM has always been a challenge, because these blocks usually contain smaller feature sizes and spacing constraints compared to traditional logic or other layout structures. At advanced nodes, critical dimension becomes smaller and smaller, until there is almost no opportunity to use optical proximity correction (OPC) and lithography to adjust the manufacturing process to mitigate the effects of any changes. The smaller process geometries, reduced supply voltages, increasing process variation, and manufacturing uncertainty mean accurate SRAM physical verification results are not only reaching new levels of difficulty, but also new levels of criticality for design success. In this paper, we explore the use of pattern matching to create an SRAM verification flow that provides both accurate, comprehensive coverage of the required checks and visual output to enable faster, more accurate error debugging. Our results indicate that pattern matching can enable foundries to improve SRAM manufacturing yield, while allowing designers to benefit from SRAM verification kits that can shorten the time to market.

Multiple-block grid adaption for an airplane geometry

NASA Technical Reports Server (NTRS)

Abolhassani, Jamshid Samareh; Smith, Robert E.

1988-01-01

Grid-adaption methods are developed with the capability of moving grid points in accordance with several variables for a three-dimensional multiple-block grid system. These methods are algebraic, and they are implemented for the computation of high-speed flow over an airplane configuration.

An integrated environmental tracer approach to characterizing groundwater circulation in a mountain block

USGS Publications Warehouse

Manning, Andrew H.; Solomon, D. Kip

2005-01-01

The subsurface transfer of water from a mountain block to an adjacent basin (mountain block recharge (MBR)) is a commonly invoked mechanism of recharge to intermountain basins. However, MBR estimates are highly uncertain. We present an approach to characterize bulk fluid circulation in a mountain block and thus MBR that utilizes environmental tracers from the basin aquifer. Noble gas recharge temperatures, groundwater ages, and temperature data combined with heat and fluid flow modeling are used to identify clearly improbable flow regimes in the southeastern Salt Lake Valley, Utah, and adjacent Wasatch Mountains. The range of possible MBR rates is reduced by 70%. Derived MBR rates (5.5–12.6 × 104 m3 d−1) are on the same order of magnitude as previous large estimates, indicating that significant MBR to intermountain basins is plausible. However, derived rates are 50–100% of the lowest previous estimate, meaning total recharge is probably less than previously thought.

Polycystins 1 and 2 mediate mechanosensation in the primary cilium of kidney cells

NASA Technical Reports Server (NTRS)

Nauli, Surya M.; Alenghat, Francis J.; Luo, Ying; Williams, Eric; Vassilev, Peter; Li, Xiaogang; Elia, Andrew E H.; Lu, Weining; Brown, Edward M.; Quinn, Stephen J.;

Feasibility of Human Skin Grafts on An Isolated But Accessible Vascular Supply on Athymic Rats As a System to Study Percutaneous Penetration and Cutaneous Injury

DTIC Science & Technology

1986-06-01

percutaneous toxicity, microcirculation of skin, nude rat 20. A.LSTICIACT (Carfrguje .r r *fd It n~e"ary7 d dn"fI b , block nyrnbor) ~Te bjctve of this researc...significant differences. An..iysis of the blood flow to the flap as a function of flap age , as well as the effect of cyclosporine, demonstrated that the...particular flap on a week to week basis. This was not related to administration of cyclosporine, body temperature, or age of the flap. The variability

An installed nacelle design code using a multiblock Euler solver. Volume 2: User guide

NASA Technical Reports Server (NTRS)

Chen, H. C.

1992-01-01

This is a user manual for the general multiblock Euler design (GMBEDS) code. The code is for the design of a nacelle installed on a geometrically complex configuration such as a complete airplane with wing/body/nacelle/pylon. It consists of two major building blocks: a design module developed by LaRC using directive iterative surface curvature (DISC); and a general multiblock Euler (GMBE) flow solver. The flow field surrounding a complex configuration is divided into a number of topologically simple blocks to facilitate surface-fitted grid generation and improve flow solution efficiency. This user guide provides input data formats along with examples of input files and a Unix script for program execution in the UNICOS environment.

Fermion-scalar conformal blocks

DOE PAGES

Iliesiu, Luca; Kos, Filip; Poland, David; ...

2016-04-13

In this study, we compute the conformal blocks associated with scalar-scalar-fermionfermion 4-point functions in 3D CFTs. Together with the known scalar conformal blocks, our result completes the task of determining the so-called ‘seed blocks’ in three dimensions. In addition, conformal blocks associated with 4-point functions of operators with arbitrary spins can now be determined from these seed blocks by using known differential operators.

Functional renormalization group analysis of tensorial group field theories on Rd

NASA Astrophysics Data System (ADS)

Geloun, Joseph Ben; Martini, Riccardo; Oriti, Daniele

2016-07-01

Rank-d tensorial group field theories are quantum field theories (QFTs) defined on a group manifold G×d , which represent a nonlocal generalization of standard QFT and a candidate formalism for quantum gravity, since, when endowed with appropriate data, they can be interpreted as defining a field theoretic description of the fundamental building blocks of quantum spacetime. Their renormalization analysis is crucial both for establishing their consistency as quantum field theories and for studying the emergence of continuum spacetime and geometry from them. In this paper, we study the renormalization group flow of two simple classes of tensorial group field theories (TGFTs), defined for the group G =R for arbitrary rank, both without and with gauge invariance conditions, by means of functional renormalization group techniques. The issue of IR divergences is tackled by the definition of a proper thermodynamic limit for TGFTs. We map the phase diagram of such models, in a simple truncation, and identify both UV and IR fixed points of the RG flow. Encouragingly, for all the models we study, we find evidence for the existence of a phase transition of condensation type.

A geologic and morphological description of Ishtar terra (Venus)

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

Sukhanov, A.L.; Kotel'nikov, V.A.; Ostrovskii, M.V.

The main part of Ishtar Terra east of Maxwell Montes is covered by systems of area dislocations in several directions that are called ''parquet.'' From the structural pictures, 1) a stable central block, 2) smaller peripheral blocks separated from the central block by faults and grabens, 3) zones of mobilized parquet, the matter of which spread down below the slope in a direction away from the central block in the form of plastic flows, and 4) partially ''parquetized'' lava rock masses are distinguished here. The Maxwell Montes were formed as the result of the collision of the central block andmore » the Lakshmi Planum.« less

The effect of nerve blockade on forearm and finger skin blood flow during body heating and cooling.

PubMed

Saumet, J L; Degoute, C S; Saumet, M; Abraham, P

1992-08-01

To determine the role of the active cutaneous vasodilatator response in forearm and finger skin, direct assessment of only skin blood flow was performed before and after musculocutaneous and median nerve blockade during whole body heating and cooling. Forearm laser Doppler flow (LDF forearm), forearm heat thermal clearance (HTC forearm), and finger laser Doppler flow (LDF finger) were monitored in the nerve blocked skin and contralateral untreated skin (control). In the pre-blockade period, no significant differences were found between experimental and control arm skin. After nerve block a significant increase occurred only in LDF finger, which rose from 4.3 +/- 0.6 to 6.0 +/- 0.5 volts (p less than 0.05). During whole body heating LDF forearm and HTC forearm increased significantly on both arms. The increase in LDF forearm was greater (p less than 0.05) in control (18.3 +/- 1.2 volts) than in nerve blocked skin (14.6 +/- 1.8 volts) and occurred earlier. The same tendency was observed in HTC forearm between nerve blocked skin (0.522 +/- 0.06 W.m-1.degrees C-1) and control 0.671 +/- 0.037 W.m-1.degrees C-1) (NS). LDF raise up to 6.6 +/- 0.5 and 6.8 +/- 0.5 volts in the blocked finger and in the control respectively. During cooling LDF finger in the control decreased to 1.3 +/- 0.1 volt and was significantly (p less than 0.05) lower than in the resting period, and lower than that in the nerve blocked finger (3.4 +/- 0.8 volts) (p less than 0.05). We conclude that the active vasodilatator system plays an important role as far as the timing and the amplitude of the cutaneous vasodilatator response to whole body heating in the forearm but not in the finger. At thermal neutrality, the vascular vasoconstrictor tone is high to the finger but not to the forearm. The vasoconstrictor response to cooling occurred only in the finger.

Semianalytical computation of path lines for finite-difference models

USGS Publications Warehouse

Pollock, D.W.

1988-01-01

A semianalytical particle tracking method was developed for use with velocities generated from block-centered finite-difference ground-water flow models. Based on the assumption that each directional velocity component varies linearly within a grid cell in its own coordinate directions, the method allows an analytical expression to be obtained describing the flow path within an individual grid cell. Given the intitial position of a particle anywhere in a cell, the coordinates of any other point along its path line within the cell, and the time of travel between them, can be computed directly. For steady-state systems, the exit point for a particle entering a cell at any arbitrary location can be computed in a single step. By following the particle as it moves from cell to cell, this method can be used to trace the path of a particle through any multidimensional flow field generated from a block-centered finite-difference flow model. -Author

40 CFR Table 5 to Subpart Hhhhhhh... - Operating Parameters, Operating Limits and Data Monitoring, Recording and Compliance Frequencies...

Code of Federal Regulations, 2013 CFR

2013-07-01

... conductivity Continuous Every 15 minutes 3-hour block average. Regenerative Adsorber Regeneration stream flow. Minimum total flow per regeneration cycle Continuous N/A Total flow for each regeneration cycle. Adsorber bed temperature. Maximum temperature Continuously after regeneration and within 15 minutes of...

40 CFR Table 5 to Subpart Hhhhhhh... - Operating Parameters, Operating Limits and Data Monitoring, Recording and Compliance Frequencies...

Code of Federal Regulations, 2014 CFR

2014-07-01

... conductivity Continuous Every 15 minutes 3-hour block average. Regenerative Adsorber Regeneration stream flow. Minimum total flow per regeneration cycle Continuous N/A Total flow for each regeneration cycle. Adsorber bed temperature. Maximum temperature Continuously after regeneration and within 15 minutes of...

A large-grain mapping approach for multiprocessor systems through data flow model. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kim, Hwa-Soo

1991-01-01

A large-grain level mapping method is presented of numerical oriented applications onto multiprocessor systems. The method is based on the large-grain data flow representation of the input application and it assumes a general interconnection topology of the multiprocessor system. The large-grain data flow model was used because such representation best exhibits inherited parallelism in many important applications, e.g., CFD models based on partial differential equations can be presented in large-grain data flow format, very effectively. A generalized interconnection topology of the multiprocessor architecture is considered, including such architectural issues as interprocessor communication cost, with the aim to identify the 'best matching' between the application and the multiprocessor structure. The objective is to minimize the total execution time of the input algorithm running on the target system. The mapping strategy consists of the following: (1) large-grain data flow graph generation from the input application using compilation techniques; (2) data flow graph partitioning into basic computation blocks; and (3) physical mapping onto the target multiprocessor using a priority allocation scheme for the computation blocks.

Rheology of the Seismogenic Crust in Southern California: Comparing Lithotectonic Blocks Defined by Past Tectonics and Major Faults

NASA Astrophysics Data System (ADS)

Hauksson, E.; Meier, M. A.; Ross, Z. E.

2017-12-01

We analyze waveform relocated seismicity (1981-2016) and other geophysical and geological datasets to determine the rheology of the crust in southern California. First, we calculate earthquake depth histograms (EDH) to quantify the depth distribution of seismicity. In general the EDHs vary between regions with a shallower mean depth and more rapid decay with depth in the brittle-ductile transition zone for high heat flow regions, which results in a shallower 95% seismicity cut-off-depth. Second, we determine depth profiles of crustal yield stress envelopes (YSE) using Byerlee's law and a non-linear dislocation creep law. We analyze the EDHs and YSEs for each lithotectonic block to identify differences in shape that may be related to lithology or past tectonic history of the crust. To model the YSE for each block we correct for measured average heat flow, strain rate, and state of stress. We determine YSEs of five different lithologies for each of the 12 lithotectonic blocks. We investigate if the EDHs are diagnostic of average lithology types. We find that the EDHs to first order follow the shape of the computed YSEs, and that the lithologies of the best matching YSEs conform with geological expectations. In particular, the blocks of the North America plate are mostly dominated by Quartzite lithology while the blocks of the Pacific plate are mostly of Diorite composition except for the Quartz dominated rifted margin in the Salton Trough. Only the extended San Gabriel block exhibits two-layer composition with Quartz underplated by Diorite. This suggests that EDHs can be used to infer the first order shape of the strength profile of the seismogenic crust. We also compare the EDH and the preferred YSE for each block with independent 3D models of Vp, Vs, Vp./Vs, and density to confirm independently the lithology of the crust. Further, we analyze the presence of mid-crustal low velocity zones that may influence the seismicity depth distribution, or onset of ductile flow.

A mixture theory approach to model co- and counter-current two-phase flow in porous media accounting for viscous coupling

NASA Astrophysics Data System (ADS)

Qiao, Y.; Andersen, P. Ø.; Evje, S.; Standnes, D. C.

2018-02-01

It is well known that relative permeabilities can depend on the flow configuration and they are commonly lower during counter-current flow as compared to co-current flow. Conventional models must deal with this by manually changing the relative permeability curves depending on the observed flow regime. In this paper we use a novel two-phase momentum-equation-approach based on general mixture theory to generate effective relative permeabilities where this dependence (and others) is automatically captured. In particular, this formulation includes two viscous coupling effects: (i) Viscous drag between the flowing phases and the stagnant porous rock; (ii) viscous drag caused by momentum transfer between the flowing phases. The resulting generalized model will predict that during co-current flow the faster moving fluid accelerates the slow fluid, but is itself decelerated, while for counter-current flow they are both decelerated. The implications of these mechanisms are demonstrated by investigating recovery of oil from a matrix block surrounded by water due to a combination of gravity drainage and spontaneous imbibition, a situation highly relevant for naturally fractured reservoirs. We implement relative permeability data obtained experimentally through co-current flooding experiments and then explore the model behavior for different flow cases ranging from counter-current dominated to co-current dominated. In particular, it is demonstrated how the proposed model seems to offer some possible interesting improvements over conventional modeling by providing generalized mobility functions that automatically are able to capture more correctly different flow regimes for one and the same parameter set.

Wave propagation and power flow in an acoustic metamaterial plate with lateral local resonance attachment

NASA Astrophysics Data System (ADS)

Wang, Ting; Sheng, Meiping; Ding, Xiaodong; Yan, Xiaowei

2018-03-01

This paper presents analysis on wave propagation and power flow in an acoustic metamaterial plate with lateral local resonance. The metamaterial is designed to have lateral local resonance systems attached to a homogeneous plate. Relevant theoretical analysis, numerical modelling and application prospect are presented. Results show that the metamaterial has two complete band gaps for flexural wave absorption and vibration attenuation. Damping can smooth and lower the metamaterial’s frequency responses in high frequency ranges at the expense of the band gap effect, and as an important factor to calculate the power flow is thoroughly investigated. Moreover, the effective mass density becomes negative and unbounded at specific frequencies. Simultaneously, power flow within band gaps are dramatically blocked from the power flow contour and power flow maps. Results from finite element modelling and power flow analysis reveal the working mechanism of the flexural wave attenuation and power flow blocked within the band gaps, where part of the flexural vibration is absorbed by the vertical resonator and the rest is transformed through four-link-mechanisms to the lateral resonators that oscillate and generate inertial forces indirectly to counterbalance the shear forces induced by the vibrational plate. The power flow is stored in the vertical and lateral local resonance, as well as in the connected plate.

Relative significance of microtopography and vegetation as controls on surface water flow on a low-gradient floodplain

USGS Publications Warehouse

Choi, Jungyill; Harvey, Judson W.

2014-01-01

Surface water flow controls water velocities, water depths, and residence times, and influences sediment and nutrient transport and other ecological processes in shallow aquatic systems. Flow through wetlands is substantially influenced by drag on vegetation stems but is also affected by microtopography. Our goal was to use microtopography data directly in a widely used wetland model while retaining the advantages of the model’s one-dimensional structure. The base simulation with no explicit treatment of microtopography only performed well for a period of high water when vegetation dominated flow resistance. Extended simulations using microtopography can improve the fit to low-water conditions substantially. The best fit simulation had a flow conductance parameter that decreased in value by 70 % during dry season such that mcrotopographic features blocked 40 % of the cross sectional width for flow. Modeled surface water became ponded and flow ceased when 85 % of the cross sectional width became blocked by microtopographic features. We conclude that vegetation drag dominates wetland flow resistance at higher water levels and microtopography dominates at low water levels with the threshold delineated by the top of microtopographic features. Our results support the practicality of predicting flow on floodplains using relatively easily measured physical and biological variables.

Diagnosis of extratropical variability in seasonal integrations of the ECMWF model

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

Ferranti, L.; Molteni, F.; Brankovic, C.

1994-06-01

Properties of the general circulation simulated by the ECMWF model are discussed using a set of seasonal integrations at T63 resolution. For each season, over the period of 5 years, 1986-1990, three integrations initiated on consecutive days were run with prescribed observed sea surface temperature (SST). This paper presents a series of diagnostics of extratropical variability in the model, with particular emphasis on the northern winter. Time-filtered maps of variability indicate that in this season there is insufficient storm track activity penetrating into the Eurasian continent. Related to this the maximum of lower-frequency variability for northern spring are more realistic.more » Blocking is defined objectively in terms of the geostrophic wind at 500 mb. Consistent with the low-frequency transience, in the Euro-Atlantic sector the position of maximum blocking in the model is displaced eastward. The composite structure of blocks over the Pacific is realistic, though their frequency is severely underestimated at all times of year. Shortcomings in the simulated wintertime general circulation were also revealed by studying the projection of 5-day mean fields onto empirical orthogonal functions (EOFs) of the observed flow. The largest differences were apparent for statistics of EOFs of the zonal mean flow. Analysis of weather regime activity, defined from the EOFs, suggested that regimes with positive PNA index were overpopulated, while the negative PNA regimes were underpopulated. A further comparison between observed and modeled low-frequency variance revealed that underestimation of low-frequency variability occurs along the same axes that explain most of the spatial structure of the error in the mean field, suggesting a common dynamical origin for these two aspects of the systematic error. 17 refs., 17 figs., 4 tabs.« less

Characterization of an Adhesion Molecule that Mediates Leukocyte Rolling on 24 h Cytokine- or Lipopolysaccharide-stimulated Bovine Endothelial Cells under Flow Conditions

PubMed Central

Jutila, Mark A.; Wilson, Eric; Kurk, Sandy

1997-01-01

Bovine γ/δ T cells and neutrophils roll on 24 h cytokine- or lipopolysaccharide-stimulated bovine fetal umbilical cord endothelial cells in assays done under physiological flow. An antibody directed against E- and L-selectin has minimal blocking effect on this rolling interaction. mAbs were raised against the stimulated bovine endothelial cells and screened for inhibition of γ/δ T cell rolling. One mAb (GR113) was identified that recognizes an antigen (GR antigen) selectively expressed by stimulated bovine endothelial cells isolated from fetal umbilical cord, mesenteric lymph nodes, and aorta. GR113 blocked bovine γ/δ T cell as well as neutrophil rolling on the 24 h-activated endothelial cells. The GR antigen was constitutively expressed at low levels on the cell surface of platelets and its expression was not upregulated after stimulation of these cells with thrombin or phorbol myristate acetate. However, stimulated platelets released a soluble, functionally active form of the molecule that selectively bound in solution to γ/δ T cells in a mixed lymphocyte preparation. GR113 mAb blocked the binding of the soluble platelet molecule to the γ/δ T cells. Soluble GR antigen also bound a subset of human lymphocytes. Cutaneous lymphocyte-associated antigen (CLA) bright human lymphocytes exhibited the greatest capacity to bind the GR antigen, though CLA was not required for binding. Subsets of both human CD4 and CD8 T cells bound the GR antigen. Immunoprecipitation experiments showed the GR antigen to be 110-120 kD M r. The binding of soluble GR antigen was inhibited by EDTA and O-sialoglycoprotease, but not neuraminidase treatment of the target cells. PMID:9362530

FLUID-STRUCTURE INTERACTION MODELS OF THE MITRAL VALVE: FUNCTION IN NORMAL AND PATHOLOGIC STATES

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

Kunzelman, K. S.; Einstein, Daniel R.; Cochran, R. P.

2007-08-29

Successful mitral valve repair is dependent upon a full understanding of normal and abnormal mitral valve anatomy and function. Computational analysis is one such method that can be applied to simulate mitral valve function in order to analyze the roles of individual components, and evaluate proposed surgical repair. We developed the first three-dimensional, finite element (FE) computer model of the mitral valve including leaflets and chordae tendineae, however, one critical aspect that has been missing until the last few years was the evaluation of fluid flow, as coupled to the function of the mitral valve structure. We present here ourmore » latest results for normal function and specific pathologic changes using a fluid-structure interaction (FSI) model. Normal valve function was first assessed, followed by pathologic material changes in collagen fiber volume fraction, fiber stiffness, fiber splay, and isotropic stiffness. Leaflet and chordal stress and strain, and papillary muscle force was determined. In addition, transmitral flow, time to leaflet closure, and heart valve sound were assessed. Model predictions in the normal state agreed well with a wide range of available in-vivo and in-vitro data. Further, pathologic material changes that preserved the anisotropy of the valve leaflets were found to preserve valve function. By contrast, material changes that altered the anisotropy of the valve were found to profoundly alter valve function. The addition of blood flow and an experimentally driven microstructural description of mitral tissue represent significant advances in computational studies of the mitral valve, which allow further insight to be gained. This work is another building block in the foundation of a computational framework to aid in the refinement and development of a truly noninvasive diagnostic evaluation of the mitral valve. Ultimately, it represents the basis for simulation of surgical repair of pathologic valves in a clinical and educational setting.« less

Refining Southern California Geotherms Using Seismologic, Geologic, and Petrologic Constraints

NASA Astrophysics Data System (ADS)

Thatcher, W. R.; Chapman, D. S.; Allam, A. A.; Williams, C. F.

2017-12-01

Lithospheric deformation in tectonically active regions depends on the 3D distribution of rheology, which is in turn critically controlled by temperature. Under the auspices of the Southern California Earthquake Center (SCEC) we are developing a 3D Community Thermal Model (CTM) to constrain rheology and so better understand deformation processes within this complex but densely monitored and relatively well-understood region. The San Andreas transform system has sliced southern California into distinct blocks, each with characteristic lithologies, seismic velocities and thermal structures. Guided by the geometry of these blocks we use more than 250 surface heat-flow measurements to define 13 geographically distinct heat flow regions (HFRs). Model geotherms within each HFR are constrained by averages and variances of surface heat flow q0 and the 1D depth distribution of thermal conductivity (k) and radiogenic heat production (A), which are strongly dependent on rock type. Crustal lithologies are not always well known and we turn to seismic imaging for help. We interrogate the SCEC Community Velocity Model (CVM) to determine averages and variances of Vp, Vs and Vp/Vs versus depth within each HFR. We bound (A, k) versus depth by relying on empirical relations between seismic wave speed and rock type and laboratory and modeling methods relating (A, k) to rock type. Many 1D conductive geotherms for each HFR are allowed by the variances in surface heat flow and subsurface (A, k). An additional constraint on the lithosphere temperature field is provided by comparing lithosphere-asthenosphere boundary (LAB) depths identified seismologically with those defined thermally as the depth of onset of partial melting. Receiver function studies in Southern California indicate LAB depths that range from 40 km to 90 km. Shallow LAB depths are correlated with high surface heat flow and deep LAB with low heat flow. The much-restricted families of geotherms that intersect peridotite solidi at the seismological LAB depth in each region require that LAB temperatures lie between 1050 to 1250˚ C, a range that is consistent with a hydrous rather than anhydrous mantle below Southern California.

Three-dimensional implicit lambda methods

NASA Technical Reports Server (NTRS)

Napolitano, M.; Dadone, A.

1983-01-01

This paper derives the three dimensional lambda-formulation equations for a general orthogonal curvilinear coordinate system and provides various block-explicit and block-implicit methods for solving them, numerically. Three model problems, characterized by subsonic, supersonic and transonic flow conditions, are used to assess the reliability and compare the efficiency of the proposed methods.

Preliminary design of an intermittent smoke flow visualization system

NASA Technical Reports Server (NTRS)

Ward, Donald T.; Myatt, James H.

1993-01-01

A prototype intermittent flow visualization system that was designed to study vortex flow field dynamics has been constructed and tested through its ground test phase. It produces discrete pulses of dense white smoke consisting of particles of terephthalic acid by the pulsing action of a fast-acting three-way valve. The trajectories of the smoke pulses can be tracked by a video imaging system without intruding in the flow around in flight. Two methods of pulsing the smoke were examined. The simplest and safest approach is to simply divert the smoke between the two outlet ports on the valve; this approach should be particularly effective if it were desired to inject smoke at two locations during the same test event. The second approach involves closing off one of the outlet ports to momentarily block the flow. The second approach requires careful control of valve dwell times to avoid excessive pressure buildup within the cartridge container. This method also increases the velocity of the smoke injected into the flow. The flow of the smoke has been blocked for periods ranging from 30 to 80 milliseconds, depending on the system volume and the length of time the valve is allowed to remain open between valve closings.

Thrombus (image)

MedlinePlus

... body. Thrombi or emboli can lodge in a blood vessel and block the flow of blood in that location depriving tissues of normal blood flow and oxygen. This can result in damage, destruction (infarction), or even death of the tissues (necrosis) in that area.

Fire resistant nuclear fuel cask

DOEpatents

Heckman, Richard C.; Moss, Marvin

1979-01-01

The disclosure is directed to a fire resistant nuclear fuel cask employing reversibly thermally expansible bands between adjacent cooling fins such that normal outward flow of heat is not interfered with, but abnormal inward flow of heat is impeded or blocked.

An experimental investigation of internal area ruling for transonic and supersonic channel flow

NASA Technical Reports Server (NTRS)

Roberts, W. B.; Vanrintel, H. L.; Rizvi, G.

1982-01-01

A simulated transonic rotor channel model was examined experimentally to verify the flow physics of internal area ruling. Pressure measurements were performed in the high speed wind tunnel at transonic speeds with Mach 1.5 and Mach 2 nozzle blocks to get an indication of the approximate shock losses. The results showed a reduction in losses due to internal area ruling with the Mach 1.5 nozzle blocks. The reduction in total loss coefficient was of the order of 17 percent for a high blockage model and 7 percent for a cut-down model.

Electroformation of Janus and patchy capsules

NASA Astrophysics Data System (ADS)

Rozynek, Zbigniew; Mikkelsen, Alexander; Dommersnes, Paul; Fossum, Jon Otto

2014-05-01

Janus and patchy particles have designed heterogeneous surfaces that consist of two or several patches with different materials properties. These particles are emerging as building blocks for a new class of soft matter and functional materials. Here we introduce a route for forming heterogeneous capsules by producing highly ordered jammed colloidal shells of various shapes with domains of controlled size and composition. These structures combine the functionalities offered by Janus or patchy particles, and those given by permeable shells such as colloidosomes. The simple assembly route involves the synergetic action of electro-hydrodynamic flow and electro-coalescence. We demonstrate that the method is robust and straightforwardly extendable to production of multi-patchy capsules. This forms a starting point for producing patchy colloidosomes with domains of anisotropic chemical surface properties, permeability or mixed liquid-solid phase domains, which could be exploited to produce functional emulsions, light and hollow supra-colloidosome structures, or scaffolds.

Effects of Polymer Structure and Relaxations on Ionic Conductivity in Anion Exchange Membranes with Quaternary Ammonium Functional Groups

NASA Astrophysics Data System (ADS)

Maes, Ashley M.

Anion exchange membranes (AEMs) are of considerable interest to developers and researchers of electrochemical conversion and storage devices such as anion exchange membrane fuel cells (AAEMFCs), alkaline polymer electrolyte electrolysers, redox flow batteries and bioelectrochemical devices. AEMs are generally in competition with more established proton exchange membranes (PEMs), but offer the potential for reduction of materials costs and greater fuel flexibility across these applications. This work includes an introduction to AEMs in the context of fuel cell technologies and some key techniques for AEM characterization. There are many synthetic strategies to incorporate cationic functional groups, which promote anion transport, into a polymer matrix. Two membrane chemistries are investigated in the following chapters. The first is based on a simple synthesis procedure that produced a membrane consisting of random, crosslinked polypropylene- ran-polyethyleneimine with quaternary ammonium functional groups. This membrane had moderate chloride ionic conductivity of 0.03 S cm -1 at 95 °C and high water uptake with minimal dimensional swelling. However, the lack of control of crosslink location and density during synthesis produced a material with a very random nature, making it a poor candidate for more fundamental transport studies. The second membrane chemistry is a block copolymer with a hydrophobic and hydrophilic block. The hydrophobic block was selected to provide favorable mechanical and barrier characteristics while a hydrophilic block was selected to provide water uptake and anion conducting functionalities. Poly(vinyl benzyl trimethyl ammonium bromide)-b-poly(methylbutylene) ([PVBTMA][Br]- b-PMB) was synthesized by partners at the University of Massachusetts-Amherst with varied degrees of functionalization (DF) along the hydrophilic block, resulting in ion exchange capacities ranging from 0.77 to 2.20 mmol g -1. Water uptake, in-plane ionic conductivity and membrane morphology were measured across a series of membranes with the original bromide (Br -) counter-ion. These bulk materials characterization experiments demonstrated that this polymer structure produces well-ordered lamellar morphology with moderate water uptake and competitive ionic conductivity (ca. 40 mS cm-1 at 90 °C and 95% relative humidity). These characteristics make it an appropriate candidate for the following more fundamental investigations of ionic conductivity mechanisms. Broadband electrical spectroscopy (BES) was conducted on one [PVBTMA][Br]- b-PMB sample in the Br- form and analyzed in conjunction with thermal stability and relaxation experiments in Chapter 4. We were able to propose two separate ionic conductivity mechanisms and relate each to physical attributes of the polymer structure. A significant thermal transition was observed at Tdelta , which resulted in a dramatic drop in conductivity. In a continued effort to characterize the ionic conductivity of these block-copolymer membranes, another BES study was conducted on three samples with varying DFs. Samples were converted to hydroxide (OH- ) form so we could contrast the Br- conductivity mechanisms to those in a more relevant counter-ion form. After analysis of the electric response of the material, combined with the thermal analysis by TGA, MDSC and DMA, conductivity mechanisms were described. As in the Br- study, conductivity involves two distinct conduction pathways, sigmaEP and sigmaIP,1. Importantly, we again observed a drop in conductivity at Tdelta in each of these samples, with Tdelta decreasing as the density of functional groups along the hydrophilic block increased. It is undesirable for this transition to occur during operation in a fuel cell or other electrochemical device, so future work to investigate strategies for inhibition are recommended.

One-Dimensional Nanostructures: Microfluidic-Based Synthesis, Alignment and Integration towards Functional Sensing Devices

PubMed Central

Xing, Yanlong; Dittrich, Petra S.

2018-01-01

Microfluidic-based synthesis of one-dimensional (1D) nanostructures offers tremendous advantages over bulk approaches e.g., the laminar flow, reduced sample consumption and control of self-assembly of nanostructures. In addition to the synthesis, the integration of 1D nanomaterials into microfluidic chips can enable the development of diverse functional microdevices. 1D nanomaterials have been used in applications such as catalysts, electronic instrumentation and sensors for physical parameters or chemical compounds and biomolecules and hence, can be considered as building blocks. Here, we outline and critically discuss promising strategies for microfluidic-assisted synthesis, alignment and various chemical and biochemical applications of 1D nanostructures. In particular, the use of 1D nanostructures for sensing chemical/biological compounds are reviewed. PMID:29303990

The Role of Magnesium in the Pathogenesis and Treatment of Glaucoma

PubMed Central

Korkmaz, Şafak; Sül, Sabahattin; Tufan, Hasan Ali; Aydın, Bahri; Dileköz, Ergin

2014-01-01

Glaucoma is characterized by chronic optic neuropathy resulting in progressive vision loss. Not only is glaucoma considered as a condition of elevated intraocular pressure (IOP), but also other risk factors may play a role in the pathogenesis of glaucomatous optic nerve damage. Vascular dysregulation in ocular blood flow and oxidative stress are currently suggested as important risk factors for glaucomatous retinal ganglion cell loss. New treatment modalities that improve ocular blood flow and reduce oxidative stress have been investigated in many studies. Magnesium (Mg) is thought to be one of the molecules that has a treatment potential in glaucoma. Mg has been shown to improve blood flow by modifying endothelial function via endothelin-1 (ET-1) and endothelial nitric oxide (NO) pathways. Mg also exhibits neuroprotective role by blocking N-methyl-D-aspartate (NMDA) receptor-related calcium influx and by inhibiting the release of glutamate, and hence protects the cell against oxidative stress and apoptosis. Both improvement in ocular blood flow and prevention of ganglion cell loss would make magnesium a good candidate for glaucoma management. Further studies on the effect of Mg may open a new therapeutic era in glaucoma. PMID:27433524

Buffer management to solve bed-blocking in the Netherlands 2000–2010. Cooperation from an integrated care chain perspective as a key success factor for managing patient flows

PubMed Central

Mur-Veeman, Ingrid; Govers, Mark

2011-01-01

Introduction Bed-blocking problems in hospitals reflect how difficult and complex it is to move patients smoothly through the chain of care. In the Netherlands, during the first decade of the 21st century, some hospitals attempted to tackle this problem by using an Intermediate Care Department (ICD) as a buffer for bed-blockers. However, research has shown that ICDs do not sufficiently solve the bed-blocking problem and that bed-blocking is often caused by a lack of buffer management. Tool Buffer management (BM) is a tool that endeavors to balance patient flow in the hospital to nursing home chain of care. Results Additional research has indicated that the absence of BM is not the result of providers’ thinking that BM is unnecessary, unethical or impossible because of unpredictable patient flows. Instead, BM is hampered by a lack of cooperation between care providers. Conclusion Although stakeholders recognize that cooperation is imperative, they often fail to take the actions necessary to realize cooperation. Our assumption is that this lack of willingness and ability to cooperate is the result of several impeding conditions as well as stakeholders’ perceptions of these conditions and the persistence of their current routines, principles and beliefs (RPBs). Discussion We recommend simultaneously working on improving the conditions and changing stakeholders’ perceptions and RPBs. PMID:21954373

Ionic plasticity and pain: The loss of descending serotonergic fibers after spinal cord injury transforms how GABA affects pain.

PubMed

Huang, Yung-Jen; Grau, James W

2018-05-02

Activation of pain (nociceptive) fibers can sensitize neural circuits within the spinal cord, inducing an increase in excitability (central sensitization) that can foster chronic pain. The development of spinally-mediated central sensitization is regulated by descending fibers and GABAergic interneurons. In adult animals, the co-transporter KCC2 maintains a low intracellular concentration of the anion Cl - . As a result, when the GABA-A receptor is engaged, Cl - flows in the neuron which has a hyperpolarizing (inhibitory) effect. Spinal cord injury (SCI) can down-regulate KCC2 and reverse the flow of Cl - . Under these conditions, engaging the GABA-A receptor can have a depolarizing (excitatory) effect that fosters the development of nociceptive sensitization. The present paper explores how SCI alters GABA function and provides evidence that the loss of descending fibers alters pain transmission to the brain. Prior work has shown that, after SCI, administration of a GABA-A antagonist blocks the development of capsaicin-induced nociceptive sensitization, implying that GABA release plays an essential role. This excitatory effect is linked to serotonergic (5HT) fibers that descend through the dorsolateral funiculus (DLF) and impact spinal function via the 5HT-1A receptor. Supporting this, blocking the 5HT-1A receptor, or lesioning the DLF, emulated the effect of SCI. Conversely, spinal application of a 5HT-1A agonist up-regulated KCC2 and reversed the effect of bicuculline treatment. Finally, lesioning the DLF reversed how a GABA-A antagonist affects a capsaicin-induced aversion in a place conditioning task; in sham operated animals, bicuculline enhanced aversion whereas in DLF-lesioned rats biciculline had an antinociceptive effect. Copyright © 2018 Elsevier Inc. All rights reserved.

A METHOD FOR USING BLOCKED AND EVENT-RELATED FMRI DATA TO STUDY “RESTING STATE” FUNCTIONAL CONNECTIVITY

PubMed Central

Fair, Damien A.; Schlaggar, Bradley L.; Cohen B.A., Alexander L.; Miezin, Francis M.; Dosenbach, Nico U.F.; Wenger, Kristin K.; Fox, Michael D.; Snyder, Abraham Z.; Raichle, Marcus E.; Petersen, Steven E.

2007-01-01

Resting state functional connectivity MRI (fcMRI) has become a particularly useful tool for studying regional relationships in typical and atypical populations. Because many investigators have already obtained large datasets of task related fMRI, the ability to use this existing task data for resting state fcMRI is of considerable interest. Two classes of datasets could potentially be modified to emulate resting state data. These datasets include: 1) “interleaved” resting blocks from blocked or mixed blocked/event-related sets, and 2) residual timecourses from event-related sets that lack rest blocks. Using correlation analysis, we compared the functional connectivity of resting epochs taken from a mixed blocked/event-related design fMRI data set and the residuals derived from event-related data with standard continuous resting state data to determine which class of data can best emulate resting state data. We show that despite some differences, the functional connectivity for the interleaved resting periods taken from blocked designs is both qualitatively and quantitatively very similar to that of “continuous” resting state data. In contrast, despite being qualitatively similar to “continuous” resting state data, residuals derived from event-related design data had several distinct quantitative differences. These results suggest that the interleaved resting state data such as those taken from blocked or mixed blocked/event-related fMRI designs are well-suited for resting state functional connectivity analyses. Although using event-related data residuals for resting state functional connectivity may still be useful, results should be interpreted with care. PMID:17239622

Netrin-1 controls sympathetic arterial innervation.

PubMed

Brunet, Isabelle; Gordon, Emma; Han, Jinah; Cristofaro, Brunella; Broqueres-You, Dong; Liu, Chun; Bouvrée, Karine; Zhang, Jiasheng; del Toro, Raquel; Mathivet, Thomas; Larrivée, Bruno; Jagu, Julia; Pibouin-Fragner, Laurence; Pardanaud, Luc; Machado, Maria J C; Kennedy, Timothy E; Zhuang, Zhen; Simons, Michael; Levy, Bernard I; Tessier-Lavigne, Marc; Grenz, Almut; Eltzschig, Holger; Eichmann, Anne

2014-07-01

Autonomic sympathetic nerves innervate peripheral resistance arteries, thereby regulating vascular tone and controlling blood supply to organs. Despite the fundamental importance of blood flow control, how sympathetic arterial innervation develops remains largely unknown. Here, we identified the axon guidance cue netrin-1 as an essential factor required for development of arterial innervation in mice. Netrin-1 was produced by arterial smooth muscle cells (SMCs) at the onset of innervation, and arterial innervation required the interaction of netrin-1 with its receptor, deleted in colorectal cancer (DCC), on sympathetic growth cones. Function-blocking approaches, including cell type-specific deletion of the genes encoding Ntn1 in SMCs and Dcc in sympathetic neurons, led to severe and selective reduction of sympathetic innervation and to defective vasoconstriction in resistance arteries. These findings indicate that netrin-1 and DCC are critical for the control of arterial innervation and blood flow regulation in peripheral organs.

Netrin-1 controls sympathetic arterial innervation

PubMed Central

Brunet, Isabelle; Gordon, Emma; Han, Jinah; Cristofaro, Brunella; Broqueres-You, Dong; Liu, Chun; Bouvrée, Karine; Zhang, Jiasheng; del Toro, Raquel; Mathivet, Thomas; Larrivée, Bruno; Jagu, Julia; Pibouin-Fragner, Laurence; Pardanaud, Luc; Machado, Maria J.C.; Kennedy, Timothy E.; Zhuang, Zhen; Simons, Michael; Levy, Bernard I.; Tessier-Lavigne, Marc; Grenz, Almut; Eltzschig, Holger; Eichmann, Anne

2014-01-01

Autonomic sympathetic nerves innervate peripheral resistance arteries, thereby regulating vascular tone and controlling blood supply to organs. Despite the fundamental importance of blood flow control, how sympathetic arterial innervation develops remains largely unknown. Here, we identified the axon guidance cue netrin-1 as an essential factor required for development of arterial innervation in mice. Netrin-1 was produced by arterial smooth muscle cells (SMCs) at the onset of innervation, and arterial innervation required the interaction of netrin-1 with its receptor, deleted in colorectal cancer (DCC), on sympathetic growth cones. Function-blocking approaches, including cell type–specific deletion of the genes encoding Ntn1 in SMCs and Dcc in sympathetic neurons, led to severe and selective reduction of sympathetic innervation and to defective vasoconstriction in resistance arteries. These findings indicate that netrin-1 and DCC are critical for the control of arterial innervation and blood flow regulation in peripheral organs. PMID:24937433

Multi-cylinder hot gas engine

DOEpatents

Corey, John A.

1985-01-01

A multi-cylinder hot gas engine having an equal angle, V-shaped engine block in which two banks of parallel, equal length, equally sized cylinders are formed together with annular regenerator/cooler units surrounding each cylinder, and wherein the pistons are connected to a single crankshaft. The hot gas engine further includes an annular heater head disposed around a central circular combustor volume having a new balanced-flow hot-working-fluid manifold assembly that provides optimum balanced flow of the working fluid through the heater head working fluid passageways which are connected between each of the cylinders and their respective associated annular regenerator units. This balanced flow provides even heater head temperatures and, therefore, maximum average working fluid temperature for best operating efficiency with the use of a single crankshaft V-shaped engine block.

A multiple-block multigrid method for the solution of the three-dimensional Euler and Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Atkins, Harold

1991-01-01

A multiple block multigrid method for the solution of the three dimensional Euler and Navier-Stokes equations is presented. The basic flow solver is a cell vertex method which employs central difference spatial approximations and Runge-Kutta time stepping. The use of local time stepping, implicit residual smoothing, multigrid techniques and variable coefficient numerical dissipation results in an efficient and robust scheme is discussed. The multiblock strategy places the block loop within the Runge-Kutta Loop such that accuracy and convergence are not affected by block boundaries. This has been verified by comparing the results of one and two block calculations in which the two block grid is generated by splitting the one block grid. Results are presented for both Euler and Navier-Stokes computations of wing/fuselage combinations.

Optimal domain decomposition strategies

NASA Technical Reports Server (NTRS)

Yoon, Yonghyun; Soni, Bharat K.

1995-01-01

The primary interest of the authors is in the area of grid generation, in particular, optimal domain decomposition about realistic configurations. A grid generation procedure with optimal blocking strategies has been developed to generate multi-block grids for a circular-to-rectangular transition duct. The focus of this study is the domain decomposition which optimizes solution algorithm/block compatibility based on geometrical complexities as well as the physical characteristics of flow field. The progress realized in this study is summarized in this paper.

Poly(oligoethylene glycol methacrylate) dip-coating: turning cellulose paper into a protein-repellent platform for biosensors.

PubMed

Deng, Xudong; Smeets, Niels M B; Sicard, Clémence; Wang, Jingyun; Brennan, John D; Filipe, Carlos D M; Hoare, Todd

2014-09-17

The passivation of nonspecific protein adsorption to paper is a major barrier to the use of paper as a platform for microfluidic bioassays. Herein we describe a simple, scalable protocol based on adsorption and cross-linking of poly(oligoethylene glycol methacrylate) (POEGMA) derivatives that reduces nonspecific adsorption of a range of proteins to filter paper by at least 1 order of magnitude without significantly changing the fiber morphology or paper macroporosity. A lateral-flow test strip coated with POEGMA facilitates effective protein transport while also confining the colorimetric reporting signal for easier detection, giving improved performance relative to bovine serum albumin (BSA)-blocked paper. Enzyme-linked immunosorbent assays based on POEGMA-coated paper also achieve lower blank values, higher sensitivities, and lower detection limits relative to ones based on paper blocked with BSA or skim milk. We anticipate that POEGMA-coated paper can function as a platform for the design of portable, disposable, and low-cost paper-based biosensors.

Effect of aerated concrete blockwork joints on the heat transfer performance uniformity

NASA Astrophysics Data System (ADS)

Pukhkal, Viktor; Murgul, Vera

2018-03-01

Analysis of data on the effect of joints of the aerated concrete blocks on the heat transfer uniformity of exterior walls was carried out. It was concluded, that the values of the heat transfer performance uniformity factor in the literature sources were obtained for the regular fragment of a wall construction by approximate addition of thermal conductivities. Heat flow patterns for the aerated concrete exterior walls amid different values of the thermal conductivity factors and design ambient air temperature of -26 °C were calculated with the use of "ELCUT" software for modelling of thermal patterns by finite element method. There were defined the values for the heat transfer performance uniformity factor, reduced total thermal resistance and heat-flux density for the exterior walls. The calculated values of the heat transfer performance uniformity factors, as a function of the coefficient of thermal conductivity of aerated concrete blocks, differ from the known data by a more rigorous thermal and physical substantiation.

Programming methodology for a general purpose automation controller

NASA Technical Reports Server (NTRS)

Sturzenbecker, M. C.; Korein, J. U.; Taylor, R. H.

1987-01-01

The General Purpose Automation Controller is a multi-processor architecture for automation programming. A methodology has been developed whose aim is to simplify the task of programming distributed real-time systems for users in research or manufacturing. Programs are built by configuring function blocks (low-level computations) into processes using data flow principles. These processes are activated through the verb mechanism. Verbs are divided into two classes: those which support devices, such as robot joint servos, and those which perform actions on devices, such as motion control. This programming methodology was developed in order to achieve the following goals: (1) specifications for real-time programs which are to a high degree independent of hardware considerations such as processor, bus, and interconnect technology; (2) a component approach to software, so that software required to support new devices and technologies can be integrated by reconfiguring existing building blocks; (3) resistance to error and ease of debugging; and (4) a powerful command language interface.

Estimation of a Stopping Criterion for Geophysical Granular Flows Based on Numerical Experimentation

NASA Astrophysics Data System (ADS)

Yu, B.; Dalbey, K.; Bursik, M.; Patra, A.; Pitman, E. B.

2004-12-01

Inundation area may be the most important factor for mitigation of natural hazards related to avalanches, debris flows, landslides and pyroclastic flows. Run-out distance is the key parameter for inundation because the front deposits define the leading edge of inundation. To define the run-out distance, it is necessary to know when a flow stops. Numerical experiments are presented for determining a stopping criterion and exploring the suitability of a Savage-Hutter granular model for computing inundation areas of granular flows. The TITAN2D model was employed to run numerical experiments based on the Savage-Hutter theory. A potentially reasonable stopping criterion was found as a function of dimensionless average velocity, aspect ratio of pile, internal friction angle, bed friction angle and bed slope in the flow direction. Slumping piles on a horizontal surface and geophysical flows over complex topography were simulated. Several mountainous areas, including Colima volcano (MX), Casita (Nic.), Little Tahoma Peak (WA, USA) and the San Bernardino Mountains (CA, USA) were used to simulate geophysical flows. Volcanic block and ash flows, debris avalanches and debris flows occurred in these areas and caused varying degrees of damage. The areas have complex topography, including locally steep open slopes, sinuous channels, and combinations of these. With different topography and physical scaling, slumping piles and geophysical flows have a somewhat different dependence of dimensionless stopping velocity on power-law constants associated with aspect ratio of pile, internal friction angle, bed friction angle and bed slope in the flow direction. Visual comparison of the details of the inundation area obtained from the TITAN2D model with models that contain some form of viscous dissipation point out weaknesses in the model that are not evident by investigation of the stopping criterion alone.

Measurement Space Drill Support

DTIC Science & Technology

2015-08-30

II) H-47 Block II (I) *H-47 Block II (II) AVN FVL Att (I) * AVN FVL Att (II) TRAC- MTRY F2025B Logistic Flow MS Drill Support FY15 Research...does not have to use other AVN /ground assets to cover the area, freeing these assets to perform other missions and potentially enhancing the

Retardation of mobile radionuclides in granitic rock fractures by matrix diffusion

NASA Astrophysics Data System (ADS)

Hölttä, P.; Poteri, A.; Siitari-Kauppi, M.; Huittinen, N.

Transport of iodide and sodium has been studied by means of block fracture and core column experiments to evaluate the simplified radionuclide transport concept. The objectives were to examine the processes causing retention in solute transport, especially matrix diffusion, and to estimate their importance during transport in different scales and flow conditions. Block experiments were performed using a Kuru Grey granite block having a horizontally planar natural fracture. Core columns were constructed from cores drilled orthogonal to the fracture of the granite block. Several tracer tests were performed using uranine, 131I and 22Na as tracers at water flow rates 0.7-50 μL min -1. Transport of tracers was modelled by applying the advection-dispersion model based on the generalized Taylor dispersion added with matrix diffusion. Scoping calculations were combined with experiments to test the model concepts. Two different experimental configurations could be modelled applying consistent transport processes and parameters. The processes, advection-dispersion and matrix diffusion, were conceptualized with sufficient accuracy to replicate the experimental results. The effects of matrix diffusion were demonstrated on the slightly sorbing sodium and mobile iodine breakthrough curves.

Multidetector thermal field-flow fractionation as a unique tool for the tacticity-based separation of poly(methyl methacrylate)-polystyrene block copolymer micelles.

PubMed

Greyling, Guilaume; Pasch, Harald

2015-10-02

Poly(methyl methacrylate)-polystyrene (PMMA-PS) micelles with isotactic and syndiotactic coronas are prepared in acetonitrile and subjected to thermal field-flow fractionation (ThFFF) analysis at various conditions of increasing temperature gradients. It is shown for the first time that multidetector ThFFF provides comprehensive information on important micelle characteristics such as size (Dh), shape (Rg/Rh), aggregation number (Z), thermal diffusion (DT) and Soret coefficients (ST) as a function of temperature from a single injection. Moreover, it is found that micelles exhibit a unique decreasing trend in DT as a function of temperature which is independent of the tacticity of the corona and the micelle preparation method used. It is also demonstrated that ThFFF can monitor micelle to vesicle transitions as a function of temperature. In addition to ThFFF, it is found from DLS analysis that the tacticity of the corona influences the critical micelle concentration and the magnitude to which micelles expand/contract with temperature. The tacticity does not, however, influence the critical micelle temperature. Furthermore, the separation of micelles based on the tacticity of the corona highlight the unique capabilities of ThFFF. Copyright © 2015 Elsevier B.V. All rights reserved.

Brain-wave Dynamics Related to Cognitive Tasks and Neurofeedback Information Flow

NASA Astrophysics Data System (ADS)

Pop-Jordanova, Nada; Pop-Jordanov, Jordan; Dimitrovski, Darko; Markovska, Natasa

2003-08-01

Synchronization of oscillating neuronal discharges has been recently correlated to the moment of perception and the ensuing motor response, with transition between these two cognitive acts "through cellular mechanisms that remain to be established"[1]. Last year, using genetic strategies, it was found that the switching off persistent electric activity in the brain blocks memory recall [2]. On the other hand, analyzing mental-neural information flow, the nobelist Eccles has formulated a fundamental hypotheses that mental events may change the probability of quantum vesicular emissions of transmitters analogously to probability functions of quantum mechanics [3]. Applying the advanced quantum modeling to molecular rotational states exposed to electric activity in brain cells, we found that the probability of transitions does not depend on the field amplitude, suggesting the electric field frequency as the possible information-bearing physical quantity [4]. In this paper, an attempt is made to inter-correlate the above results on frequency aspects of neural transitions induced by cognitive tasks. Furthermore, considering the consecutive steps of mental-neural information flow during the biofeedback training to normalize EEG frequencies, the rationales for neurofeedback efficiency have been deduced.

Delayed soil thawing affects root and shoot functioning and growth in Scots pine.

PubMed

Repo, Tapani; Lehto, Tarja; Finér, Leena

2008-10-01

In boreal regions, soil can remain frozen after the start of the growing season. We compared relationships between root characteristics and water relations in Scots pine (Pinus sylvestris L.) saplings subjected to soil frost treatments before and during the first week of the growing period in a controlled environment experiment. Delayed soil thawing delayed the onset of sap flow or totally blocked it if soil thawing lagged the start of the growing period by 7 days. This effect was reflected in the electrical impedance of needles and trunks and in the relative electrolyte leakage of needles. Prolonged soil frost reduced or completely inhibited root growth. In unfrozen soil, limited trunk sap flow was observed despite unfavorable aboveground growing conditions (low temperature, low irradiance, short photoperiod). Following the earliest soil thaw, sap flow varied during the growing season, depending on light and temperature conditions, phenological stage of the plant and the amount of live needles in the canopy. The results suggest that delayed soil thawing can reduce tree growth, and if prolonged, it can be lethal.

Dilatancy and shear thickening of particle suspensions

NASA Astrophysics Data System (ADS)

Bonn, Daniel

2013-03-01

Shear thickening is a fascinating subject, as 99.9% of complex fluids are thinning; thickening systems thus are the ``exception to the rule'' that needs to be understood. Moreover, such tunable systems show very promising applications, e.g. to block large underground pores in oil recovery to maintain a constant oil flow by plugging water filled pores (an approach used in oil recovery by e.g. Shell), or to manufacture bulletproof vests that are comfortable to wear, but stop bullets nonetheless. We study the rheology of non-Brownian particle suspensions (notably, cornstarch) that exhibit shear thickening. Using magnetic resonance imaging (MRI), the local properties of the flow are obtained by the determination of local velocity profiles and concentrations in a Couette cell. We also perform macroscopic rheology experiments in different geometries. The results suggest that the shear thickening is a consequence of dilatancy: the system under flow attempts to dilate but instead undergoes a jamming transition, because it is confined. This proposition is confirmed by an independent measurement of the dilation of the suspension as a function of the shear rate.

Investigating Phase-Change-Induced Flow in Gas Diffusion Layers in Fuel Cells with X-ray Computed Tomography

DOE PAGES

Shum, Andrew D.; Parkinson, Dilworth Y.; Xiao, Xianghui; ...

2017-10-07

The performance of polymer-electrolyte fuel cells is heavily dependent on proper management of liquid water. One particular reason is that liquid water can collect in the gas diffusion layers (GDLs) blocking the reactant flow to the catalyst layer. This results in increased mass-transport losses. At higher temperatures, evaporation of water becomes a dominant water-removal mechanism and specifically phase-change-induced (PCI) flow is present due to thermal gradients. This study used synchrotron based micro X-ray computed tomography (CT) to visualize and quantify the water distribution within gas diffusion layers subject to a thermal gradient. Plotting saturation as a function of through-plane distancemore » quantitatively shows water redistribution, where water evaporates at hotter locations and condenses in colder locations. The morphology of the 2 GDLs on the micro-scale, as well as evaporating water clusters, are resolved, indicating that the GDL voids are slightly prolate, whereas water clusters are oblate. From the mean radii of water distributions and visual inspection, it is observed that larger water clusters evaporate faster than smaller ones.« less

Specific residues of the cytoplasmic domains of cardiac inward rectifier potassium channels are effective antifibrillatory targets

PubMed Central

Noujaim, Sami F.; Stuckey, Jeanne A.; Ponce-Balbuena, Daniela; Ferrer-Villada, Tania; López-Izquierdo, Angelica; Pandit, Sandeep; Calvo, Conrado J.; Grzeda, Krzysztof R.; Berenfeld, Omer; Sánchez Chapula, José A.; Jalife, José

2010-01-01

Atrial and ventricular tachyarrhythmias can be perpetuated by up-regulation of inward rectifier potassium channels. Thus, it may be beneficial to block inward rectifier channels under conditions in which their function becomes arrhythmogenic (e.g., inherited gain-of-function mutation channelopathies, ischemia, and chronic and vagally mediated atrial fibrillation). We hypothesize that the antimalarial quinoline chloroquine exerts potent antiarrhythmic effects by interacting with the cytoplasmic domains of Kir2.1 (IK1), Kir3.1 (IKACh), or Kir6.2 (IKATP) and reducing inward rectifier potassium currents. In isolated hearts of three different mammalian species, intracoronary chloroquine perfusion reduced fibrillatory frequency (atrial or ventricular), and effectively terminated the arrhythmia with resumption of sinus rhythm. In patch-clamp experiments chloroquine blocked IK1, IKACh, and IKATP. Comparative molecular modeling and ligand docking of chloroquine in the intracellular domains of Kir2.1, Kir3.1, and Kir6.2 suggested that chloroquine blocks or reduces potassium flow by interacting with negatively charged amino acids facing the ion permeation vestibule of the channel in question. These results open a novel path toward discovering antiarrhythmic pharmacophores that target specific residues of the cytoplasmic domain of inward rectifier potassium channels.—Noujaim, S. F., Stuckey, J. A., Ponce-Balbuena, D., Ferrer-Villada, T., López-Izquierdo, A., Pandit, S., Calvo, C. J., Grzeda, K. R., Berenfeld, O., Sánchez Chapula, J. A., Jalife, J. Specific residues of the cytoplasmic domains of cardiac inward rectifier potassium channels are effective antifibrillatory targets. PMID:20585026

Influence of micromixer characteristics on polydispersity index of block copolymers synthesized in continuous flow microreactors.

PubMed

Rosenfeld, Carine; Serra, Christophe; Brochon, Cyril; Hadziioannou, Georges

2008-10-01

The influence of interdigital multilamination micromixer characteristics on monomer conversions, molecular weights and especially on the polydispersity index of block copolymers synthesized continuously in two microtube reactors is investigated. The micromixers are used to mix, before copolymerization, a polymer solution with different viscosities and the second monomer. Different geometries of micromixer (number of microchannels, characteristic lengths) have been studied. It was found that polydispersity indices of the copolymers follow a linear relationship with the Reynolds number in the micromixer, represented by a form factor. Thus, beside the operating conditions (nature of the first block and comonomer flow rate), the choice of the micromixer geometry and dimension is essential to control the copolymerization in terms of molecular weights and polydispersity indices. This linear correlation allows the prediction of copolymer features. It can also be a new method to optimize existing micromixers or design other geometries so that mixing could be more efficient.

Investigation of upwind, multigrid, multiblock numerical schemes for three dimensional flows. Volume 1: Runge-Kutta methods for a thin layer Navier-Stokes solver

NASA Technical Reports Server (NTRS)

Cannizzaro, Frank E.; Ash, Robert L.

1992-01-01

A state-of-the-art computer code has been developed that incorporates a modified Runge-Kutta time integration scheme, upwind numerical techniques, multigrid acceleration, and multi-block capabilities (RUMM). A three-dimensional thin-layer formulation of the Navier-Stokes equations is employed. For turbulent flow cases, the Baldwin-Lomax algebraic turbulence model is used. Two different upwind techniques are available: van Leer's flux-vector splitting and Roe's flux-difference splitting. Full approximation multi-grid plus implicit residual and corrector smoothing were implemented to enhance the rate of convergence. Multi-block capabilities were developed to provide geometric flexibility. This feature allows the developed computer code to accommodate any grid topology or grid configuration with multiple topologies. The results shown in this dissertation were chosen to validate the computer code and display its geometric flexibility, which is provided by the multi-block structure.

Complex Chern-Simons Theory at Level k via the 3d-3d Correspondence

NASA Astrophysics Data System (ADS)

Dimofte, Tudor

2015-10-01

We use the 3d-3d correspondence together with the DGG construction of theories T n [ M] labelled by 3-manifolds M to define a non-perturbative state-integral model for Chern-Simons theory at any level k, based on ideal triangulations. The resulting partition functions generalize a widely studied k = 1 state-integral, as well as the 3d index, which is k = 0. The Chern-Simons partition functions correspond to partition functions of T n [ M] on squashed lens spaces L( k, 1). At any k, they admit a holomorphic-antiholomorphic factorization, corresponding to the decomposition of L( k, 1) into two solid tori, and the associated holomorphic block decomposition of the partition functions of T n [ M]. A generalization to L( k, p) is also presented. Convergence of the state integrals, for any k, requires triangulations to admit a positive angle structure; we propose that this is also necessary for the DGG gauge theory T n [ M] to flow to a desired IR SCFT.

Adenosine triphosphate-sensitive potassium channel blocking agent ameliorates, but the opening agent aggravates, ischemia/reperfusion-induced injury. Heart function studies in nonfibrillating isolated hearts.

PubMed

Tosaki, A; Hellegouarch, A

1994-02-01

This study was conducted to elucidate the role of the adenosine triphosphate (ATP)-sensitive potassium channel blocking agent glibenclamide and the opener cromakalim in the mechanism of reperfusion-induced injury. Recently, ATP-sensitive potassium channel openers have been proposed to reduce ischemia/reperfusion-induced injury, including arrhythmias and heart function. Thus, one might hypothesize that pharmacologic agents that enhance the loss of potassium ions in the myocardium through ATP-sensitive potassium channels would be arrhythmogenic, and agents that interfere with tissue potassium ion loss would be antiarrhythmic. Isolated "working" guinea pig hearts and phosphorus-31 nuclear magnetic resonance spectroscopy were used to study the recovery of myocardial function and phosphorus compounds after 30, 40 and 50 min of normothermic global ischemia followed by reperfusion in untreated control and glibenclamide- and cromakalim-treated groups. After 30 min of ischemia, 1, 3, 10 and 30 mumol/liter of glibenclamide dose-dependently reduced the incidence of reperfusion-induced ventricular fibrillation (total) from its control value of 92% to 75%, 33% (p < 0.05), 33% (p < 0.05) and 42% (p < 0.05), respectively. The incidence of ventricular tachycardia followed the same pattern. A reduction of arrhythmias was also observed after 40 and 50 min of ischemia followed by reperfusion in the glibenclamide-treated hearts. Cromakalim, at the same concentrations, did not reduce the incidence of reperfusion-induced arrhythmias. During reperfusion, glibenclamide (3 and 10 mumol/liter) improved the recovery of coronary blood flow, aortic flow, myocardial contractility and tissue ATP and creatine phosphate content, but cromakalim failed to ameliorate the recovery of postischemic myocardium compared with that in the drug-free control hearts. The preservation of myocardial potassium ions and phosphorus compounds by glibenclamide can improve the recovery of postischemic function, but the use of ATP-sensitive potassium channel openers as antihypertensive or antiarrhythmic agents may be of particular concern in those postinfarction patients who are known to be at high risk for sudden cardiac death.

Facilitating higher-fidelity simulations of axial compressor instability and other turbomachinery flow conditions

NASA Astrophysics Data System (ADS)

Herrick, Gregory Paul

The quest to accurately capture flow phenomena with length-scales both short and long and to accurately represent complex flow phenomena within disparately sized geometry inspires a need for an efficient, high-fidelity, multi-block structured computational fluid dynamics (CFD) parallel computational scheme. This research presents and demonstrates a more efficient computational method by which to perform multi-block structured CFD parallel computational simulations, thus facilitating higher-fidelity solutions of complicated geometries (due to the inclusion of grids for "small'' flow areas which are often merely modeled) and their associated flows. This computational framework offers greater flexibility and user-control in allocating the resource balance between process count and wall-clock computation time. The principal modifications implemented in this revision consist of a "multiple grid block per processing core'' software infrastructure and an analytic computation of viscous flux Jacobians. The development of this scheme is largely motivated by the desire to simulate axial compressor stall inception with more complete gridding of the flow passages (including rotor tip clearance regions) than has been previously done while maintaining high computational efficiency (i.e., minimal consumption of computational resources), and thus this paradigm shall be demonstrated with an examination of instability in a transonic axial compressor. However, the paradigm presented herein facilitates CFD simulation of myriad previously impractical geometries and flows and is not limited to detailed analyses of axial compressor flows. While the simulations presented herein were technically possible under the previous structure of the subject software, they were much less computationally efficient and thus not pragmatically feasible; the previous research using this software to perform three-dimensional, full-annulus, time-accurate, unsteady, full-stage (with sliding-interface) simulations of rotating stall inception in axial compressors utilized tip clearance periodic models, while the scheme here is demonstrated by a simulation of axial compressor stall inception utilizing gridded rotor tip clearance regions. As will be discussed, much previous research---experimental, theoretical, and computational---has suggested that understanding clearance flow behavior is critical to understanding stall inception, and previous computational research efforts which have used tip clearance models have begged the question, "What about the clearance flows?''. This research begins to address that question.

Liquid-Nitrogen Test for Blocked Tubes

NASA Technical Reports Server (NTRS)

Wagner, W. R.

1984-01-01

Nondestructive test identifies obstructed tube in array of parallel tubes. Trickle of liquid nitrogen allowed to flow through tube array until array accumulates substantial formation of frost from moisture in air. Flow stopped and warm air introduced into inlet manifold to heat tubes in array. Tubes still frosted after others defrosted identified as obstructed tubes. Applications include inspection of flow systems having parallel legs.

3D Seismic Interpretation of a Plio-Pleistocene Mass Transport Deposit in the Deepwater Taranaki Basin of New Zealand

NASA Astrophysics Data System (ADS)

Rusconi, Francisco Jose

A series of Plio-Pleistocene mass transport deposits (MTD) have been identified in the deepwater Taranaki Basin, in New Zealand, using the Romney 3D seismic survey, which covers an area of approximately 2000 km2. One of these MTDs has been chosen for description and interpretation based on high confidence mapping of its boundary surfaces. The deposit exhibits an array of interesting features similar to those documented by researchers elsewhere plus a unique basal feature unlike those previously observed. The basal shear surface exhibits erosional features such as grooves, "monkey fingers", and glide tracks. Internally, the MTD is typically characterized by low impedance, chaotic, semi-transparent reflectors surrounding isolated coherent packages of seismic facies interpreted as intact blocks rafted within the mass transport complex. Distally, the deposit presents outrunner blocks and pressure ridges. The new element described in this work consists of a composite feature that includes a protruding obstacle ("shield block") on the paleo-seafloor that acted as a barrier to subsequent flows as they advanced downslope. These blocks disrupt the incoming flow and result in elongate, downflow negative features ("erosional shadow scours"), which are then infilled by the mass transport deposit, and are preserved as elongate isochore thicks. Kinematic evidence provided by various structures suggests that the MTD flow direction was SE-NW toward bathyal depths. The features presented and the absence of extensional headwall structures, such as local arcuate glide planes and rotated slide blocks, suggest that this part of the deposit belongs to the translational to distal domain of the MTD, and its source area is expected to be somewhere toward the SE in a paleo continental slope.

Inducing microstructural changes in Nafion by incorporating graphitic carbon nitride to enhance the vanadium-blocking effect.

PubMed

Wu, Chunxiao; Lu, Shanfu; Zhang, Jin; Xiang, Yan

2018-03-14

Two-dimensional graphitic carbon nitride (g-C 3 N 4 ) nanosheets are introduced into a Nafion matrix to prepare a 'vanadium-blocking' recast Nafion membrane for vanadium redox flow battery (VRFB) applications. After 0.2 wt% g-C 3 N 4 nanosheets are incorporated, the vanadium ion permeability of the composite membrane decreases from 3.3 × 10 -7 cm 2 min -1 to 3.8 × 10 -9 cm 2 min -1 , which is a reduction of two orders of magnitude in comparison to the pristine recast Nafion membrane. This satisfactory result contributes to the physical blocking effect as well as the Donnan effect from the 2D morphology and functional amino groups of g-C 3 N 4 nanosheets. Notably, this work reveals that the g-C 3 N 4 nanosheets can help reinforce the vanadium-blocking effect by changing the microstructure of Nafion in addition to the well-known effects mentioned above. The g-C 3 N 4 nanosheets induce shrinkage in the original spherical structure of the ion cluster and generate a new lamellar structure. Correspondingly, the amorphous phase of Nafion is interrupted, and the membrane crystallinity is reduced. The VRFB with an optimized composite membrane achieves a high coulombic efficiency of 97% and an energy efficiency of 83% at a current density of 160 mA cm -2 . Meanwhile, the battery exhibited excellent lifetime stability during a 100 charge-discharge cycling test.

Autonomous unmanned air vehicles (UAV) techniques

NASA Astrophysics Data System (ADS)

Hsu, Ming-Kai; Lee, Ting N.

2007-04-01

The UAVs (Unmanned Air Vehicles) have great potentials in different civilian applications, such as oil pipeline surveillance, precision farming, forest fire fighting (yearly), search and rescue, boarder patrol, etc. The related industries of UAVs can create billions of dollars for each year. However, the road block of adopting UAVs is that it is against FAA (Federal Aviation Administration) and ATC (Air Traffic Control) regulations. In this paper, we have reviewed the latest technologies and researches on UAV navigation and obstacle avoidance. We have purposed a system design of Jittering Mosaic Image Processing (JMIP) with stereo vision and optical flow to fulfill the functionalities of autonomous UAVs.

Honeycomb-like PLGA- b-PEG Structure Creation with T-Junction Microdroplets.

PubMed

Gultekinoglu, Merve; Jiang, Xinyue; Bayram, Cem; Ulubayram, Kezban; Edirisinghe, Mohan

2018-06-04

Amphiphilic block copolymers are widely used in science owing to their versatile properties. In this study, amphiphilic block copolymer poly(lactic- co-glycolic acid)- block-poly(ethylene glycol) (PLGA- b-PEG) was used to create microdroplets in a T-junction microfluidic device with a well-defined geometry. To compare interfacial characteristics of microdroplets, dichloromethane (DCM) and chloroform were used to prepare PLGA- b-PEG solution as an oil phase. In the T-junction device, water and oil phases were manipulated at variable flow rates from 50 to 300 μL/min by increments of 50 μL/min. Fabricated microdroplets were directly collected on a glass slide. After a drying period, porous two-dimensional and three-dimensional structures were obtained as honeycomb-like structure. Pore sizes were increased according to increased water/oil flow rate for both DCM and chloroform solutions. Also, it was shown that increasing polymer concentration decreased the pore size of honeycomb-like structures at a constant water/oil flow rate (50:50 μL/min). Additionally, PLGA- b-PEG nanoparticles were also obtained on the struts of honeycomb-like structures according to the water solubility, volatility, and viscosity properties of oil phases, by the aid of Marangoni flow. The resulting structures have a great potential to be used in biomedical applications, especially in drug delivery-related studies, with nanoparticle forming ability and cellular responses in different surface morphologies.

Investigation of obstacle effect to improve conjugate heat transfer in backward facing step channel using fast simulation of incompressible flow

NASA Astrophysics Data System (ADS)

Nouri-Borujerdi, Ali; Moazezi, Arash

2018-01-01

The current study investigates the conjugate heat transfer characteristics for laminar flow in backward facing step channel. All of the channel walls are insulated except the lower thick wall under a constant temperature. The upper wall includes a insulated obstacle perpendicular to flow direction. The effect of obstacle height and location on the fluid flow and heat transfer are numerically explored for the Reynolds number in the range of 10 ≤ Re ≤ 300. Incompressible Navier-Stokes and thermal energy equations are solved simultaneously in fluid region by the upwind compact finite difference scheme based on flux-difference splitting in conjunction with artificial compressibility method. In the thick wall, the energy equation is obtained by Laplace equation. A multi-block approach is used to perform parallel computing to reduce the CPU time. Each block is modeled separately by sharing boundary conditions with neighbors. The developed program for modeling was written in FORTRAN language with OpenMP API. The obtained results showed that using of the multi-block parallel computing method is a simple robust scheme with high performance and high-order accurate. Moreover, the obtained results demonstrated that the increment of Reynolds number and obstacle height as well as decrement of horizontal distance between the obstacle and the step improve the heat transfer.

How the continents deform: The evidence from tectonic geodesy

USGS Publications Warehouse

Thatcher, Wayne R.

2009-01-01

Space geodesy now provides quantitative maps of the surface velocity field within tectonically active regions, supplying constraints on the spatial distribution of deformation, the forces that drive it, and the brittle and ductile properties of continental lithosphere. Deformation is usefully described as relative motions among elastic blocks and is block-like because major faults are weaker than adjacent intact crust. Despite similarities, continental block kinematics differs from global plate tectonics: blocks are much smaller, typically ∼100–1000 km in size; departures from block rigidity are sometimes measurable; and blocks evolve over ∼1–10 Ma timescales, particularly near their often geometrically irregular boundaries. Quantitatively relating deformation to the forces that drive it requires simplifying assumptions about the strength distribution in the lithosphere. If brittle/elastic crust is strongest, interactions among blocks control the deformation. If ductile lithosphere is the stronger, its flow properties determine the surface deformation, and a continuum approach is preferable.

The age and composition of the pre-Cenozoic basement of the Jalisco Block: implications for and relation to the Guerrero composite terrane

NASA Astrophysics Data System (ADS)

Valencia, Victor A.; Righter, Kevin; Rosas-Elguera, Jose; López-Martínez, Margarita; Grove, Marty

2013-09-01

The Jalisco Block is thought to be part of the Guerrero terrane, but the nature and age of the underlying crystalline basement are largely unknown. We have collected a suite of schists, granitoids, and weakly metamorphosed marine sediments from various parts of the Jalisco Block including Atenguillo and Ameca, Mascota and San Sebastián, Cuale, Puerto Vallarta, Punta Mita, Yelapa, and Tomatlán. The schists range in age from 135 to 161 Ma, with many exhibiting Proterozoic and Phanerozoic zircon ages. The granitoids range in age from 65 to 90 Ma, and are calc-alkaline compositionally—similar to granitoids from the Puerto Vallarta and Los Cabos batholiths. The Jalisco granitoids also experienced similar uplift rates to granitoids from the regions to the north and south of the Jalisco Block. The marine sediments yield a maximum depositional age of 131 Ma, and also contain a significant zircon population with ages extending back to the Archean. Granitoids from this study define two age groups, even after the effects of thermal resetting and different closure temperatures are considered. The 66.8-Ma silicic ash flow tuff near Union de Tula significantly expands the extent of this Cretaceous-Paleocene age ash flow tuff unit within the Jalisco Block, and we propose calling the unit "Carmichael silicic ash flow tuff volcanic succession" in honor of Ian Carmichael. The ages of the basement schists in the Jalisco Block fully overlap with the ages of terranes of continental Mexico, and other parts of the Guerrero terrane in the south, confirming the autochthonous origin of the Jalisco Block rather than exotic arc or allochthonous origin. Geologic data, in combination with geochronologic and oxygen isotopic data, suggest the evolution of SW Mexico with an early 200-1,200-Ma passive margin, followed by steep subduction in a continental arc setting at 160-165 Ma, then shallower subduction by 135 Ma, and finally, emplacement of granitoids at 65-90 Ma.

Intravascular application of electrocautery in a rabbit model of abdominal aortic endarterectomy

PubMed Central

Wang, Chuan; Xin, Yi; Li, Na; Li, Diankun; Li, Jingxing; Gu, Chengxiong

2017-01-01

Effective therapies for preventing perioperative complications such as thrombosis and inflammation after coronary endarterectomy (CE) are lacking. Electrocoagulation electrotomes have been routinely used in surgery for their cutting, clotting, and hemostatic properties. As strong flattening tools, their electrocautery function may prevent mechanical intimal-adventitial injury to arterial circulation and attenuate stenosis. The present study investigated the effects of intravascular application of electrocautery on ameliorating inflammation and thrombosis in a rabbit model of abdominal aortic endarterectomy. New Zealand rabbits were randomly divided into the sham, control (endarterectomy), and study (endarterectomy + electrocautery) groups with 10 in each group. Abdominal aortas were partially blocked and intima was removed. Electrocautery was performed with an electrocoagulation electrotome through the entire blocked vessel lumen. Vascular ultrasound parameters, molecular biological and histological characteristics of the abdominal aorta including vascular diameter, blood flow velocity, serum interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels, and apoptosis rate of vascular endothelial cells (ECs) were evaluated postoperatively by vascular Doppler ultrasound, ELISA, real-time RT-PCR, flow cytometry, and immunofluorescence at various time points. Compared with the endarterectomy + electrocautery group, the isolated endarterectomy group had significantly increased levels and gene expression of TNF-α and IL-6 (P<0.05), and rates of apoptosis of vascular ECs (P<0.05), with gradual vascular stenosis and decreased blood flow velocity. In conclusion, intravascular application of electrocautery has favorable short-term effects on the abdominal aorta and can reduce inflammation in a rabbit model of abdominal aorta endarterectomy. Long-term anti-inflammatory and anti-thrombotic effects on arterial remodeling and the clinical value of electrocautery in CE remain to be determined. PMID:28672932

Intravascular application of electrocautery in a rabbit model of abdominal aortic endarterectomy.

PubMed

Wang, Chuan; Xin, Yi; Li, Na; Li, Diankun; Li, Jingxing; Gu, Chengxiong

2017-07-01

Effective therapies for preventing perioperative complications such as thrombosis and inflammation after coronary endarterectomy (CE) are lacking. Electrocoagulation electrotomes have been routinely used in surgery for their cutting, clotting, and hemostatic properties. As strong flattening tools, their electrocautery function may prevent mechanical intimal-adventitial injury to arterial circulation and attenuate stenosis. The present study investigated the effects of intravascular application of electrocautery on ameliorating inflammation and thrombosis in a rabbit model of abdominal aortic endarterectomy. New Zealand rabbits were randomly divided into the sham, control (endarterectomy), and study (endarterectomy + electrocautery) groups with 10 in each group. Abdominal aortas were partially blocked and intima was removed. Electrocautery was performed with an electrocoagulation electrotome through the entire blocked vessel lumen. Vascular ultrasound parameters, molecular biological and histological characteristics of the abdominal aorta including vascular diameter, blood flow velocity, serum interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels, and apoptosis rate of vascular endothelial cells (ECs) were evaluated postoperatively by vascular Doppler ultrasound, ELISA, real-time RT-PCR, flow cytometry, and immunofluorescence at various time points. Compared with the endarterectomy + electrocautery group, the isolated endarterectomy group had significantly increased levels and gene expression of TNF-α and IL-6 (P<0.05), and rates of apoptosis of vascular ECs (P<0.05), with gradual vascular stenosis and decreased blood flow velocity. In conclusion, intravascular application of electrocautery has favorable short-term effects on the abdominal aorta and can reduce inflammation in a rabbit model of abdominal aorta endarterectomy. Long-term anti-inflammatory and anti-thrombotic effects on arterial remodeling and the clinical value of electrocautery in CE remain to be determined.

Tsunamis generated by subaerial mass flows

USGS Publications Warehouse

Walder, S.J.; Watts, P.; Sorensen, O.E.; Janssen, K.

2003-01-01

Tsunamis generated in lakes and reservoirs by subaerial mass flows pose distinctive problems for hazards assessment because the domain of interest is commonly the "near field," beyond the zone of complex splashing but close enough to the source that wave propagation effects are not predominant. Scaling analysis of the equations governing water wave propagation shows that near-field wave amplitude and wavelength should depend on certain measures of mass flow dynamics and volume. The scaling analysis motivates a successful collapse (in dimensionless space) of data from two distinct sets of experiments with solid block "wave makers." To first order, wave amplitude/water depth is a simple function of the ratio of dimensionless wave maker travel time to dimensionless wave maker volume per unit width. Wave amplitude data from previous laboratory investigations with both rigid and deformable wave makers follow the same trend in dimensionless parameter space as our own data. The characteristic wavelength/water depth for all our experiments is simply proportional to dimensionless wave maker travel time, which is itself given approximately by a simple function of wave maker length/water depth. Wave maker shape and rigidity do not otherwise influence wave features. Application of the amplitude scaling relation to several historical events yields "predicted" near-field wave amplitudes in reasonable agreement with measurements and observations. Together, the scaling relations for near-field amplitude, wavelength, and submerged travel time provide key inputs necessary for computational wave propagation and hazards assessment.

Groundwater flow cycling between a submarine spring and an inland fresh water spring

USGS Publications Warehouse

Davis, J. Hal; Verdi, Richard

2014-01-01

Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half.

Dynamical Languages

NASA Astrophysics Data System (ADS)

Xie, Huimin

The following sections are included: * Definition of Dynamical Languages * Distinct Excluded Blocks * Definition and Properties * L and L″ in Chomsky Hierarchy * A Natural Equivalence Relation * Symbolic Flows * Symbolic Flows and Dynamical Languages * Subshifts of Finite Type * Sofic Systems * Graphs and Dynamical Languages * Graphs and Shannon-Graphs * Transitive Languages * Topological Entropy

Inviscid and viscous flow modelling of complex aircraft configurations using the CFD simulation system sauna

NASA Astrophysics Data System (ADS)

Peace, Andrew J.; May, Nicholas E.; Pocock, Mark F.; Shaw, Jonathon A.

1994-04-01

This paper is concerned with the flow modelling capabilities of an advanced CFD simulation system known by the acronym SAUNA. This system is aimed primarily at complex aircraft configurations and possesses a unique grid generation strategy in its use of block-structured, unstructured or hybrid grids, depending on the geometric complexity of the addressed configuration. The main focus of the paper is in demonstrating the recently developed multi-grid, block-structured grid, viscous flow capability of SAUNA, through its evaluation on a number of configurations. Inviscid predictions are also presented, both as a means of interpreting the viscous results and with a view to showing more completely the capabilities of SAUNA. It is shown that accuracy and flexibility are combined in an efficient manner, thus demonstrating the value of SAUNA in aerodynamic design.

Synaptotagmin 3 deficiency in T cells impairs recycling of the chemokine receptor CXCR4 and thereby inhibits CXCL12 chemokine-induced migration.

PubMed

Masztalerz, Agnieszka; Zeelenberg, Ingrid S; Wijnands, Yvonne M; de Bruijn, Rosalie; Drager, Angelika M; Janssen, Hans; Roos, Ed

2007-01-15

Synaptotagmins regulate vesicle trafficking and fusion of vesicles with membranes - processes that have been implicated in cell migration. We therefore hypothesized that synaptotagmins play a role in T-cell migration. Amongst synaptotagmins 1-11, we found synaptotagmin 3 (SYT3) to be the only one that is expressed in T cells. CXCR4-triggered migration was inhibited by antisense synaptotagmin 3 mRNA and by the isolated C2B domain, known to impair oligomerization of all synaptotagmins, but not by a C2B mutant that binds Ca(2+) but does not block oligomerization. The C2B domain also blocked CXCR4-triggered actin polymerization and invasion. However, CXCR4-dependent adhesion in flow was not affected. Surprisingly, we found that little or no SYT3 is present near the plasma membrane but that it is mainly localized in multivesicular bodies, which also contained much of the CXCR4. Impaired SYT3 function blocked CXCR4 recycling and thus led to reduced surface levels of CXCR4. Migration was restored by overexpression of CXCR4. We conclude that STT3 is essential for CXCR4 recycling in T cells and thereby for the maintenance of high CXCR4 surface levels required for migration.

Friction and dynamics of rock avalanches travelling on glaciers

NASA Astrophysics Data System (ADS)

De Blasio, Fabio Vittorio

2014-05-01

Rock avalanches travelling on glaciers often exhibit effective friction coefficient lower than those on a rocky terrain. After briefly considering some data of rock avalanches on glaciers, the physics of sliding of solid objects on icy surfaces is reviewed, and a model is put forward for the mechanics of rock avalanche sliding on ice accounting for the formation of a natural lubricating layer. It is suggested that at the beginning of the flow of a rock avalanche, friction results from rocky blocks ploughing on ice. As the erosion continues, a gouge of ice particles results, which clogs the interstices between blocks and may partially melt as a consequence of the production of frictional heat. This conceptual model is numerically investigated for a slab travelling on ice. The results show an increase in mobility as a function of slab thickness, travelled length, and the gravity field, in agreement with case studies. The results are useful to interpret the peculiar features of rock avalanches travelling on icy surfaces such as digitations, out-runner blocks, and longitudinal furrows. The lubrication theory for landslides on ice proposed here may provide a framework for understanding landslides on Earth and for future modelling; in addition, it may help elucidate the presence of similar landslide deposits on the surface of Mars.

Does regional compared to local anaesthesia influence outcome after arteriovenous fistula creation?

PubMed

Macfarlane, Alan James Robert; Kearns, Rachel Joyce; Aitken, Emma; Kinsella, John; Clancy, Marc James

2013-08-19

An arteriovenous fistula is the optimal form of vascular access in patients with end-stage renal failure requiring haemodialysis. Unfortunately, approximately one-third of fistulae fail at an early stage. Different anaesthetic techniques can influence factors associated with fistula success, such as intraoperative blood flow and venous diameter. A regional anaesthetic brachial plexus block results in vasodilatation and improved short- and long-term fistula flow compared to the infiltration of local anaesthetic alone. This, however, has not yet been shown in a large trial to influence long-term fistula patency, the ultimate clinical measure of success.The aim of this study is to compare whether a regional anaesthetic block, compared to local anaesthetic infiltration, can improve long-term fistula patency. This study is an observer-blinded, randomised controlled trial. Patients scheduled to undergo creation of either brachial or radial arteriovenous fistulae will receive a study information sheet, and consent will be obtained in keeping with the Declaration of Helsinki. Patients will be randomised to receive either: (i) an ultrasound guided brachial plexus block using lignocaine with adrenaline and levobupivicaine, or (ii) local anaesthetic infiltration with lignocaine and levobupivicaine.A total of 126 patients will be recruited. The primary outcome is fistula primary patency at three months. Secondary outcomes include primary patency at 1 and 12 months, secondary patency and fistula flow at 1, 3 and 12 months, flow on first haemodialysis, procedural pain, patient satisfaction, change in cephalic vein diameter pre- and post-anaesthetic, change in radial or brachial artery flow pre- and post-anaesthetic, alteration of the surgical plan after anaesthesia as guided by vascular mapping with ultrasound, and fistula infection requiring antibiotics. No large randomised controlled trial has examined the influence of brachial plexus block compared with local anaesthetic infiltration on the long-term patency of arteriovenous fistulae. If the performance of brachial plexus block increases fistulae patency, this will have significant clinical and financial benefits as the number of patients able to commence haemodialysis when planned should increase, and the number of "redo" or revision procedures should be reduced. This study has been approved by the West of Scotland Research Ethics Committee 5 (reference no. 12/WS/0199) and is registered with the ClinicalTrials.gov database (reference no. NCT01706354).

Research on Segmentation Monitoring Control of IA-RWA Algorithm with Probe Flow

NASA Astrophysics Data System (ADS)

Ren, Danping; Guo, Kun; Yao, Qiuyan; Zhao, Jijun

2018-04-01

The impairment-aware routing and wavelength assignment algorithm with probe flow (P-IA-RWA) can make an accurate estimation for the transmission quality of the link when the connection request comes. But it also causes some problems. The probe flow data introduced in the P-IA-RWA algorithm can result in the competition for wavelength resources. In order to reduce the competition and the blocking probability of the network, a new P-IA-RWA algorithm with segmentation monitoring-control mechanism (SMC-P-IA-RWA) is proposed. The algorithm would reduce the holding time of network resources for the probe flow. It segments the candidate path suitably for the data transmitting. And the transmission quality of the probe flow sent by the source node will be monitored in the endpoint of each segment. The transmission quality of data can also be monitored, so as to make the appropriate treatment to avoid the unnecessary probe flow. The simulation results show that the proposed SMC-P-IA-RWA algorithm can effectively reduce the blocking probability. It brings a better solution to the competition for resources between the probe flow and the main data to be transferred. And it is more suitable for scheduling control in the large-scale network.

Characterization of Bovine Serum Albumin Blocking Efficiency on Epoxy-Functionalized Substrates for Microarray Applications.

PubMed

Sun, Yung-Shin; Zhu, Xiangdong

2016-10-01

Microarrays provide a platform for high-throughput characterization of biomolecular interactions. To increase the sensitivity and specificity of microarrays, surface blocking is required to minimize the nonspecific interactions between analytes and unprinted yet functionalized surfaces. To block amine- or epoxy-functionalized substrates, bovine serum albumin (BSA) is one of the most commonly used blocking reagents because it is cheap and easy to use. Based on standard protocols from microarray manufactories, a BSA concentration of 1% (10 mg/mL or 200 μM) and reaction time of at least 30 min are required to efficiently block epoxy-coated slides. In this paper, we used both fluorescent and label-free methods to characterize the BSA blocking efficiency on epoxy-functionalized substrates. The blocking efficiency of BSA was characterized using a fluorescent scanner and a label-free oblique-incidence reflectivity difference (OI-RD) microscope. We found that (1) a BSA concentration of 0.05% (0.5 mg/mL or 10 μM) could give a blocking efficiency of 98%, and (2) the BSA blocking step took only about 5 min to be complete. Also, from real-time and in situ measurements, we were able to calculate the conformational properties (thickness, mass density, and number density) of BSA molecules deposited on the epoxy surface. © 2015 Society for Laboratory Automation and Screening.

Hashimoto's thyroiditis with heterogeneous antithyrotropin receptor antibodies: unique epitopes may contribute to the regulation of thyroid function by the antibodies.

PubMed

Akamizu, T; Kohn, L D; Hiratani, H; Saijo, M; Tahara, K; Nakao, K

2000-06-01

Blocking-type TSH-binding inhibitor Igs (TBIIs) are known to cause hypothyroidism and an atrophic thyroid gland in patients with primary myxedema. They can block the activity of thyroid-stimulating antibodies (TSAbs) in Graves' patients as well as the activity of TSH. The majority of the epitopes for these blocking-type TBIIs have been, and are shown herein, to be present on the C-terminal region of the extracellular domain of the human TSH receptor (TSHR), whereas those for Graves' TSAbs are on the N-terminus. We report on a patient with Hashimoto's thyroiditis who suffered from mild hypothyroidism and a moderately sized goiter. Her serum had a potent blocking-type TBII and a weak TSAb in human and porcine TSHR systems. Using human TSHR/lutropin-CG receptor chimeras, we determined that the functional epitope of her blocking-type TBII was uniquely present on the N-terminal, rather than the C-terminal, region of the extracellular domain of the TSHR, unlike the case for blocking-type TBIIs in primary myxedema patients. The epitope of her TSAb was also unusual. Although the functional epitopes of most TSAbs are known to involve the N-terminal region of the receptor, her TSAb epitope did not seem to be present solely on the N- or C-terminus of the extracellular domain of the receptor. Blocking-type TBIIs from patients with primary myxedema blocked her TSAb activity as well as stimulation by TSH; her blocking-type TBII was able to only partially block her TSAb. In contrast, her blocking-type TBII almost completely blocked TSAbs from Graves' patients. Thus, we suggest that the unique epitopes of this patient's heterogeneous population of TSH receptor antibodies, at least in part, contribute to regulation of her thyroid function.

Nanoporous Block Polymer Thin Films Functionalized with Bio-Inspired Ligands for the Efficient Capture of Heavy Metal Ions from Water.

PubMed

Weidman, Jacob L; Mulvenna, Ryan A; Boudouris, Bryan W; Phillip, William A

2017-06-07

Heavy metal contamination of water supplies poses a serious threat to public health, prompting the development of novel and sustainable treatment technologies. One promising approach is to molecularly engineer the chemical affinity of a material for the targeted removal of specific molecules from solution. In this work, nanoporous polymer thin films generated from tailor-made block polymers were functionalized with the bio-inspired moieties glutathione and cysteamine for the removal of heavy metal ions, including lead and cadmium, from aqueous solutions. In a single equilibrium stage, the films achieved removal rates of the ions in excess of 95%, which was consistent with predictions based on the engineered material properties. In a flow-through configuration, the thin films achieved an even greater removal rate of the metal ions. Furthermore, in mixed ion solutions the capacity of the thin films, and corresponding removal rates, did not demonstrate any reduction due to competitive adsorption effects. After such experiments the material was repeatedly regenerated quickly with no observed loss in capacity. Thus, these membranes provide a sustainable platform for the efficient purification of lead- and cadmium-contaminated water sources to safe levels. Moreover, their straightforward chemical modifications suggest that they could be engineered to treat sources containing other recalcitrant environmental contaminants as well.

Pharmacological blocking of the osteoclastic biocorrosion of surgical stainless steel in vitro.

PubMed

Lionetto, S; Little, A; Moriceau, G; Heymann, D; Decurtins, M; Plecko, M; Filgueira, L; Cadosch, D

2013-04-01

In vitro studies suggest that human osteoclasts (OC) are able to corrode surgical stainless steel 316L (SS). The aim of this study was to investigate whether osteoclastic biocorrosion can be blocked pharmacologically. Human OCs were generated in vitro from peripheral blood monocytic cells (PBMCs) in the presence of OC differentiation cytokines. The osteoclastic viability, differentiation, and resorptive function (on both bone and SS) were assessed using standard colorimetric cell viability assay 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenil)-2H-tetrazolium, inner salt (MTS), fluorescence microscopy, tartrate-resistant acid phosphatase expression (flow cytometry), and scanning electron microscopy. OCs cultured on SS were exposed to nontoxic concentrations of bafilomycin A1, amiloride hydrochloride, or zoledronic acid. The extent of biocorrosion was quantified using atomic emission spectrometry (to measure the concentration of metal ions released into the supernatant) and scanning electron microscopy. PBMCs differentiated into mature and functional OC in the presence of all the drugs used. Osteoclastic resorption of SS was noted with differences in the resorption pattern for all drug treatments. Under the drug treatments, single areas of osteoclastic resorption were larger in size but less abundant when compared with positive controls. None of the drugs used were able to inhibit osteoclastic biocorrosion of SS. Copyright © 2012 Wiley Periodicals, Inc.

Paleomagnetic quantification of upper-plate deformation during Miocene detachment faulting in the Mohave Mountains, Arizona

USGS Publications Warehouse

Pease, V.; Hillhouse, J.W.; Wells, R.E.

2005-01-01

Paleomagnetic data from Miocene (???20 Ma) volcanic rocks and dikes of west central Arizona reveal the tilt history of Proterozoic crystalline rocks in the hanging wall of the Chemehuevi-Whipple Mountains detachment fault. We obtained magnetization data from dikes and flows in two structural blocks encompassing Crossman Peak and Standard Wash in the Mohave Mountains. In the Crossman block the dike swarm records two components of primary magnetization: (1) CNH, a normal polarity, high-unblocking-temperature or high-coercivity component (inclination, I = 48.5??, declination, D = 6.4??), and (2) CRHm, a reversed polarity, high-temperature or high-coercivity component (I = -33.6??, D = 197.5??). Argon age spectra imply that the dikes have not been reheated above 300??C since their emplacement, and a baked-contact test suggests that the magnetization is likely to be Miocene in age. CRHm deviates from the expected direction of the Miocene axial dipole field and is best explained as a result of progressive tilting about the strike of the overlying andesite flows. These data suggest that the Crossman block was tilted 60?? to the southwest prior to intrusion of the vertical dike swarm, and the block continued to tilt during a magnetic field reversal to normal polarity (CNH). Miocene dikes in the Crossman block are roughly coplanar, so the younger dikes with normal polarity magnetization intruded along planes of weakness parallel to the earlier reversed polarity swarm. An alternative explanation involves CNH magnetization being acquired later during hydrothermal alteration associated with the final stages of dike emplacement. In the Standard Wash block, the primary component of magnetization is a dual-polarity, high-temperature or high-coercivity component (SWHl, I = 7.2??,D= 0.7??). To produce agreement between the expected Miocene magnetic direction and the SWH component requires (1) correcting for a 56?? tilt about the strike of flow bedding and (2) removing a counterclockwise vertical-axis rotation of 20??. The two rotations restore the Standard Wash dikes to vertical, make parallel the dike layering in the Crossman and Standard Wash blocks, and align the strikes of bedding in both blocks. Geologic mapping, geochemical evidence, and paleomagnetic data are consistent with the upper plate of the Mohave Mountains having tilted in response to formation of the underlying detachment fault.

Is the blocking of drainage channels in upland peats an effective means of reducing DOC loss at the catchment scale?

NASA Astrophysics Data System (ADS)

Turner, Kate; Worrall, Fred

2010-05-01

Only 3% of the earths land surface is covered by peatland yet boreal and subarctic peatlands store approximately 15-30% of the World's soil carbon as peat (Limpens et al. 2008). In comparison British bogs store carbon equivalent to 20 years worth of national emissions. The loss of carbon from these areas in the form of dissolved organic carbon (DOC) is increasing and it is expected to have grown by up to 40% by 2018. Extensive drainage of UK peatlands has been associated with dehydration of the peat, an increase in water colour and a loss of carbon storage. It has been considered that the blocking of these drainage channels represents a means of peat restoration and a way of reducing DOC loss. This study aims to assess the effectiveness of this drain blocking at both an individual drain scale and at a larger catchment scale. Gibson et al. (2009) considered the effects of blocking at a solely individual drain scale finding that a 20% drop in DOC export was recorded post blocking however this decrease was due to a reduction in water yield rather than a reduction in DOC concentration with the concentration record showing no significant reduction. The effect of external parameters become more pronounced as the DOC record is examined at larger scales. The catchment is an open system and water chemistry will be influence by mixing with water from other sources. Also it is likely that at some point the drains will cut across slope leading to the flow of any highly coloured water down slope, bypassing the blockages, and entering the surface waters downstream. Degradation of DOC will occur naturally downstream due to the effects of light and microbial activity. There is, consequently, a need to examine the wider effects of drain blocking at a catchment scale to ensure that what is observed for one drain transfers to the whole catchment. A series of blocked and unblocked catchments were studied in Upper Teesdale, Northern England. Drain water samples were taken at least daily at nine localities. These sites were located such that individual drains could be monitored in the context of a larger catchment. Water table depth, flow and weather parameters were recorded along with the collection of runoff and soil water samples. A detailed sampling programme was undertaken in which a series of drains were studied in the 12 months prior to and post blocking. This approach has allowed the effects of blocking on the carbon budget, water balance and flow pathways to be considered. Results indicate that the blocking of zero order drainage channels leads to a decrease in DOC export on an individual drain scale. However, this is due to a reduction in water yield rather than concentration. Concentrations are seen to rise by a small yet statistically significant amount in blocked zero order streams. The effect at a larger scale is more complex. Annual export values in the unblocked control catchment show a rise from zero to first order streams indicating that water is being added to the system at this scale from external spatially variable sources. This pattern is also recognised in the blocked catchment. The DOC concentration record in blocked drains at this larger scale however indicated a reduction relative to the unblocked catchment. This reduction points to a change in flow pathways post blocking as highly coloured water re-navigates its way downstream. References: Gibson H, Worrall F, Burt TP, Adamson JK (2009) DOC budgets of drained peat catchments: implications for DOC production in peat soils, Hydrological Processes 23(13) 1901-1911 Limpens J (2008) Peatlands and the carbon cycle: from local processes to global implications- a synthesis, Biogeosciences 5 1475-1491

40 CFR Table 2 to Subpart Jjjjj of... - Operating Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Kiln equipped with a WS a. Maintain the average scrubber pressure drop for each 3-hour block period at... average scrubber liquid pH for each 3-hour block period at or above the average scrubber liquid pH established during the performance test; and c. Maintain the average scrubber liquid flow rate for each 3-hour...

40 CFR Table 2 to Subpart Jjjjj of... - Operating Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Kiln equipped with a WS a. Maintain the average scrubber pressure drop for each 3-hour block period at... average scrubber liquid pH for each 3-hour block period at or above the average scrubber liquid pH established during the performance test; and c. Maintain the average scrubber liquid flow rate for each 3-hour...

Comparative utility of gated myocardial perfusion imaging and transthoracic coronary flow reserve for the assessment of coronary artery disease in patients with left bundle branch block.

PubMed

Pavlovic, Smiljana; Sobic-Saranovic, Dragana; Djordjevic-Dikic, Ana; Beleslin, Branko; Stepanovic, Jelena; Artiko, Vera; Giga, Vojislav; Petrasinovic, Zorica; Ostojic, Miodrag; Vujisic-Tesic, Bosiljka; Obradovic, Vladimir

2010-04-01

To compare the diagnostic utility of gated single-photon emission computed tomography (SPECT) methoxy isobutyl isonitrile (MIBI) myocardial perfusion imaging and transthoracic Doppler echocardiography (TTDE) coronary flow reserve (CFR) to coronary angiography for detecting coronary artery disease (CAD) in patients with left bundle branch block (LBBB). Forty-three patients with complete LBBB and an intermediate pretest probability for CAD underwent dipyridamole stress TTDE and gated SPECT MIBI during the same session and coronary angiography within a month. The parameters of myocardial perfusion (summed stress score, summed difference scores) regional wall function (wall motion score, wall thickening score) and ejection fraction were derived using the 17-segment model and 4D-MSPECT software. TTDE variables included peak flow velocity at rest and during hyperemia in left anterior descending artery (LAD), based on which CFR was calculated (normal>2). Perfusion ischemic scores were significantly higher in group 1 with angiographic evidence of greater than 50% LAD stenosis compared with group 2 with less than 50% LAD stenosis (summed stress score 12.4+/-5.5 vs. 8.3+/-3.5, P<0.05, summed difference score 3.7+/-1.2 vs. 1.1+/-0.3, P<0.01, respectively). Left ventricular regional wall function and ejection fraction were not different between the two groups. CFR was significantly lower in group 1 than in group 2 (1.65+/-0.21 vs. 2.31+/-0.28, P<0.001). Gated SPECT MIBI and CFR had similar sensitivity (88 vs. 88%), specificity (80 vs. 84%), and accuracy (84 vs. 86%) for detecting CAD in patients with LBBB. The agreement between the two methods was 85%. Our results show comparable diagnostic utility and high agreement between gated SPECT MIBI perfusion imaging and TTDE CFR assessment for detecting CAD in patients with LBBB. The advantage of gated SPECT MIBI over TTDE CFR measurements is the ability to assess the perfusion abnormalities in multiple vascular territories during the same procedure, which is convenient for detecting multi-vessel disease in patients with LBBB.

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

PubMed Central

Hanif, Sadaf; Oschmann, Bernd; Spetter, Dmitri; Tahir, Muhammad Nawaz; Tremel, Wolfgang

2017-01-01

This paper describes the controlled radical polymerization of an ionic-liquid monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles, which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials. PMID:28904612

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells.

PubMed

Hanif, Sadaf; Oschmann, Bernd; Spetter, Dmitri; Tahir, Muhammad Nawaz; Tremel, Wolfgang; Zentel, Rudolf

2017-01-01

This paper describes the controlled radical polymerization of an ionic-liquid monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO 2 nanoparticles, which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO 2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials.

PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM: Alterations in uteroplacental hemodynamics during melatonin supplementation in sheep and cattle.

PubMed

Lemley, C O; Vonnahme, K A

2017-05-01

Compromised placental function can result in fetal growth restriction which is associated with greater risk of neonatal morbidity and mortality. Large increases in transplacental nutrient and waste exchange, which support the exponential increase in fetal growth during the last half of gestation, are dependent primarily on the rapid growth and vascularization of the uteroplacenta. The amplitude of melatonin secretion has been associated with improved oxidative status and altered cardiovascular function in several mammalian species; however, melatonin mediated alterations of uteroplacental capacity in sheep and cattle are lacking. Therefore, our laboratories are examining uteroplacental blood flow and fetal development during maternal melatonin supplementation. Using a mid- to late-gestation ovine model of intrauterine growth restriction, we examined uteroplacental blood flow and fetal growth during supplementation with 5 mg/d of dietary melatonin. Maternal nutrient restriction decreased uterine arterial blood flow, while melatonin supplementation increased umbilical arterial blood flow compared with non-supplemented controls. Although melatonin treatment did not rescue fetal weight in nutrient restricted ewes; we observed disproportionate fetal size and fetal organ development. Elevated fetal concentrations of melatonin may result in altered blood flow distribution during important time points of development. These melatonin specific responses on umbilical arterial hemodynamics and fetal development may be partially mediated through vascular melatonin receptors. Recently, we examined the effects of supplementing Holstein heifers with 20 mg/d of dietary melatonin during the last third of gestation. Uterine arterial blood flow was increased by 25% and total serum antioxidant capacity was increased by 43% in melatonin supplemented heifers vs. non-supplemented controls. In addition, peripheral concentrations of progesterone were decreased in melatonin supplemented heifers vs. non-supplemented controls. Using an in vitro model, melatonin treatment increased the activity of cytochrome P450 2C, a progesterone inactivating enzyme, which was blocked by treatment with the melatonin receptor antagonist, luzindole. Elucidating the consequences of specific hormonal supplements on the continual plasticity of placental function will allow us to determine important endogenous mediators of offspring growth and development.

The renal response to electrical stimulation of renal efferent sympathetic nerves in the anaesthetized greyhound.

PubMed Central

Poucher, S M; Karim, F

1991-01-01

1. The effect of direct electrical stimulation of the renal efferent nerves upon renal haemodynamics and function was studied in greyhounds anaesthetized with chloralose and artificially ventilated. The left kidney was neurally and vascularly isolated, and perfused with blood from one of the femoral arteries at a constant pressure of 99 +/- 1 mmHg. Renal blood flow was measured with a cannulating electromagnetic flow probe placed in the perfusion circuit, glomerular filtration rate by creatinine clearance, urinary sodium excretion by flame photometry and solute excretion by osmometry. Beta-Adrenergic receptor activation was blocked by the infusion of dl-propranolol (17 micrograms kg-1 min-1). The peripheral ends of the ligated renal nerves were stimulated at 0.5, 1.0, 1.5 and 2.0 Hz. 2. At 0.5 Hz frequency only osmolar excretion was significantly reduced (10.3 +/- 3.2%, P less than 0.05, n = 6). Reductions in sodium excretion (53.6 +/- 8.5%, P less than 0.01, n = 6) and water excretion (26.9 +/- 8.0%, P less than 0.05, n = 6) and further reductions of osmolar excretion (20.7 +/- 3.7%, P less than 0.01, n = 6) were observed at 1.0 Hz; however, these were observed in the absence of significant changes in renal blood flow and glomerular filtration rate. Significant reductions were observed in glomerular filtration rate at 1.5 Hz (16.3 +/- 4.1%, P less than 0.02, n = 5) and in renal blood flow at 2.0 Hz (13.1 +/- 4.0%, P less than 0.05, n = 5). Further reductions in urine flow and sodium excretion were also observed at these higher frequencies. 3. These results clearly show that significant changes in renal tubular function can occur in the absence of changes in renal blood flow and glomerular filtration rate when the renal nerves are stimulated electrically from a zero baseline activity up to a frequency of 1.5 Hz. Higher frequencies caused significant changes in both renal haemodynamics and function. PMID:2023113

Sedimentological and geochimical features of chaotic deposits in the Ventimiglia Flysch (Roya-Argentina valley- NW Italy)

NASA Astrophysics Data System (ADS)

Perotti, Elena; Bertok, Carlo; D'Atri, Anna; Martire, Luca; Musso, Alessia; Piana, Fabrizio; Varrone, Dario

2010-05-01

The Ventimiglia Flysch is a Upper Eocene turbidite succession deposited in the SE part of the Eocene Alpine foreland basin, truncated at the top by the basal thrust of the Helminthoides Flysch, a Ligurian tectonic unit that presently covers part of the Dauphinois and Briançonnais successions of Western Ligurian Alps. The Ventimiglia Flysch is made of alternations of sandstones and shales. The upper part is characterized by chaotic deposits. The chaotic deposits are constituted by: - km to hm-sized intrabasinal blocks (Ventimiglia Flysch) and extrabasinal blocks (Cretaceous sediments of Dauphinois Domain, Nummulite Limestone of the Alpine foreland basin and Helminthoides Flysch ); - conglomerates with block-in-matrix fabric interpreted as debris flow deposits. They occur as m-thick beds interbedded with the normal turbidite succession or locally as matrix of the larger blocks. Debris flow clasts show: - different sizes, ranging from metre to centimetre; - different shapes, from rounded to subangular; - different lithologies, such as fine-grained quartz-arenites, marls, dark shales and fine-grained calcisiltites. They may be referred to both coeval, intrabasinal lithologies (Ventimiglia Flysch), and extrabasinal formations (Nummulite Limestone, Globigerina Marl and Helminthoides Flysch). The clasts are disposed randomly into a chaotic matrix that consists of a dark mudstone in which submillimetre- to millimetre-sized lithic grains, with the same compositions of larger clasts, are present. Locally matrix consists of sandstones with quartz and feldspar grains and fragments of nummulitids that suggest reworking of unlithified Eocene sediments. Cathodoluminescence observations allow the distinction of two kinds of clasts: dull clasts that underwent a cementation before the formation of conglomerates, and clasts with the same orange luminescence as the matrix that may be interpreted as soft mud clasts that were cemented together with the matrix. Debris flow deposits are cross-cut by a network of crumpled and broken veins, 10's mm to cm-large, filled with orange luminescing calcite and locally with quartz. Their complex cross-cutting relationships with clasts and matrix show that several systems of veins are present, that may be referred to different fracturing events. Some clasts are crossed or bordered by veins that end at the edge of the clasts. These veins show the same features as those that crosscut the whole rock. This indicates reworking of plastic sediments crossed by calcite-filled veins by mass gravity flows. Polyphase debris flow processes, proceeding along with fluid expulsion and veining, are thus documented. Ellipsoidal, dm-large concretions of cemented pelites also occur. They represent a previous phase of concretionary growth within homogenous pelites subsequently involved in the mass gravity flow. Stable O and C isotope analyses, performed on matrix, clasts, concretions and veins, show: - δ13C close to normal marine values (-3 to 0 δ13C ‰ PDB) - δ18O markedly negative (-9 to -7 δ18O ‰ PDB) that could be related to precipitation from relatively hot waters (60-70 ° C). The block-in-matrix fabric and the variable composition and size of blocks show that these sediments are a sedimentary mélange related to mass wasting processes involving both extrabasinal and intrabasinal sediments. These gravitational movements took place along slopes of submarine tectonic ridges created by transpressional faults (Piana et al., 2009) that juxtaposed tectonic slices of different paleogeographic domains (Dauphinois, Briançonnais, Ligurian Units) in Late Eocene times, and involved both rock fall processes of huge blocks of lithified, older formations, and debris flows of unlithified intrabasinal sediment. Faults also acted as conduits for an upward flow of hot fluids supersaturated in calcium carbonate. These fluids crossed unlithified sediments close to the sea floor resulting in localized concretionary cementation and formation of vein swarms within unlithified sediments prone to subsequent mass wasting.

Indicators of Student Flow Rates in Honduras: An Assessment of an Alternative Methodology, with Two Methodologies for Estimating Student Flow Rates. BRIDGES Research Report No. 6.

ERIC Educational Resources Information Center

Cuadra, Ernesto; Crouch, Luis

Student promotion, repetition, and dropout rates constitute the basic data needed to forecast future enrollment and new resources. Information on student flow is significantly related to policy formulation aimed at improving internal efficiency, because dropping out and grade repetition increase per pupil cost, block access to eligible school-age…

Video-Seismic coupling for debris flow study at Merapi Volcano, Indonesia

NASA Astrophysics Data System (ADS)

Budi Wibowo, Sandy; Lavigne, Franck; Mourot, Philippe; Sukatja, Bambang

2016-04-01

Previous lahar disasters caused at least 44.252 death toll worldwide from 1600 to 2010 of which 52 % was due to a single event in the late 20th century. The need of a better understanding of lahar flow behavior makes general public and stakeholders much more curious than before. However, the dynamics of lahar in motion is still poorly understood because data acquisition of active flows is difficult. This research presents debris-flow-type lahar on February 28, 2014 at Merapi volcano in Indonesia. The lahar dynamics was studied in the frame of the SEDIMER Project (Sediment-related Disasters following the 2010 centennial eruption of Merapi Volcano, Java, Indonesia) based on coupling between video and seismic data analysis. We installed a seismic station at Gendol river (1090 meters asl, 4.6 km south from the summit) consisting of two geophones placed 76 meters apart parallel to the river, a high definition camera on the edge of the river and two raingauges at east and west side of the river. The results showed that the behavior of this lahar changed continuously during the event. The lahar front moved at an average speed of 4.1 m/s at the observation site. Its maximum velocity reached 14.5 m/s with a peak discharge of 473 m3/s. The maximum depth of the flow reached 7 m. Almost 600 blocks of more than 1 m main axis were identified on the surface of the lahar during 36 minutes, which represents an average block discharge of 17 blocks per minute. Seismic frequency ranged from 10 to 150 Hz. However, there was a clear difference between upstream and downstream seismic characteristics. The interpretation related to this difference could be improved by the results of analysis of video recordings, especially to differentiate the debris flow and hyperconcentrated flow phase. The lahar video is accessible online to the broader community (https://www.youtube.com/watch?v=wlVssRoaPbw). Keywords: lahar, video, seismic signal, debris flow, hyperconcentrated flow, Merapi, Indonesia.

Volume 2: Explicit, multistage upwind schemes for Euler and Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Elmiligui, Alaa; Ash, Robert L.

1992-01-01

The objective of this study was to develop a high-resolution-explicit-multi-block numerical algorithm, suitable for efficient computation of the three-dimensional, time-dependent Euler and Navier-Stokes equations. The resulting algorithm has employed a finite volume approach, using monotonic upstream schemes for conservation laws (MUSCL)-type differencing to obtain state variables at cell interface. Variable interpolations were written in the k-scheme formulation. Inviscid fluxes were calculated via Roe's flux-difference splitting, and van Leer's flux-vector splitting techniques, which are considered state of the art. The viscous terms were discretized using a second-order, central-difference operator. Two classes of explicit time integration has been investigated for solving the compressible inviscid/viscous flow problems--two-state predictor-corrector schemes, and multistage time-stepping schemes. The coefficients of the multistage time-stepping schemes have been modified successfully to achieve better performance with upwind differencing. A technique was developed to optimize the coefficients for good high-frequency damping at relatively high CFL numbers. Local time-stepping, implicit residual smoothing, and multigrid procedure were added to the explicit time stepping scheme to accelerate convergence to steady-state. The developed algorithm was implemented successfully in a multi-block code, which provides complete topological and geometric flexibility. The only requirement is C degree continuity of the grid across the block interface. The algorithm has been validated on a diverse set of three-dimensional test cases of increasing complexity. The cases studied were: (1) supersonic corner flow; (2) supersonic plume flow; (3) laminar and turbulent flow over a flat plate; (4) transonic flow over an ONERA M6 wing; and (5) unsteady flow of a compressible jet impinging on a ground plane (with and without cross flow). The emphasis of the test cases was validation of code, and assessment of performance, as well as demonstration of flexibility.

Ultrasound-guided axillary brachial plexus block versus local infiltration anesthesia for arteriovenous fistula creation at the forearm for hemodialysis in patients with chronic renal failure.

PubMed

Nofal, W H; El Fawal, S M; Shoukry, A A; Sabek, Eas; Malak, Wfa

2017-01-01

The primary failure rate for arteriovenous fistula (AVF) creation under local anesthesia for hemodialysis is about 30%. Axillary brachial plexus block (BPB) may improve blood flow through blood vessels used in fistula creation; it may improve the AVF blood flow and thus may reduce the primary failure rate after 3 months. Hundred and forty patients with chronic renal failure scheduled for AVF creation for hemodialysis were divided into two equal groups; Group 1 (AxBP-G) received ultrasound (US) guided axillary BPB, and Group 2 (LI-G) received local infiltration. We recorded the measurements of the brachial and radial arteries before and after anesthesia and the AVF blood flow in both groups at three different time points. Furthermore, the primary failure rate was recorded in each group and compared. After anesthesia, the mean radial artery blood flow in the AxBP-group was 3.52 ml/min more than the LI-group, and the brachial artery diameter was also 0.68 mm more than in the LI-group, both differences were statistically significant ( P < 0.05). There were significant increases ( P < 0.05) in the AVF blood flow in the AxBP-group more than the LI-group with mean differences of 29.6, 69.8, and 27.2 ml/min at 4 h, 1 week, and 3 months, respectively. The overall mean of AVF blood flow was 42.21 ml/min more in the AxBP group than the LI-group a difference which is statistically significant ( P < 0.001). The primary failure rate was 17% in the AxBP group versus 30% in the LI-group; however, this difference is not significant statistically ( P = 0.110). The US-guided axillary block increases AVF blood flow significantly more than local infiltration and nonsignificantly decreases the primary failure rate of the AVF after 3 months.

Relationships Between Gum Chewing and Stroop Test: A Pilot Study.

PubMed

Kawakami, Y; Takeda, T; Konno, M; Suzuki, Y; Kawano, Y; Ozawa, T; Kondo, Y; Sakatani, K

2017-01-01

Cognitive function tends to decrease with aging, therefore maintenance of this function in an aging society is an important issue. The role of chewing in nutrition is important. Although several studies indicate that gum chewing is thought to improve cognitive function, it remains debatable whether gum-chewing does in fact improve cognitive function. The Stroop test is a psychological tool used to measure cognition. A shorter reaction time indicates a mean higher behavioral performance and higher levels of oxy-Hb concentration. fNIRS is a powerful, non-invasive imaging technique offering many advantages, including compact size, no need for specially equipped facilities, and the potential for real-time measurement. The left dorsolateral prefrontal cortex (DLPFC) seems to be mainly involved in the Stroop task.The aim of the present study was to investigate the hypothesis that gum-chewing changes cerebral blood flow in the left DLPFC during the Stroop test, and also changes the reaction time. Fourteen healthy volunteers (mean age 26.9 years) participated in this study after providing written informed consent. A piece of tasteless gum weighing 1.0 g was used. Each session was designed in a block manner, i.e. 4 rests (30 s) and 3 blocks of task (30 s). A computerized Stroop test was used (including both congruent and incongruent Stroop tasks) which calculates a response time automatically. The Binominal test was used for comparisons (p < 0.05). The results show activation of the left DLPFC during the Stroop task and that gum chewing significantly increases responses/oxy-Hb concentration and significantly shortens the reaction time.

Impacts of ditch blocking on peatland hydrology - the benefits of long-term monitoring

NASA Astrophysics Data System (ADS)

Holden, Joseph; Green, Sophie; Baird, Andy; Chapman, Pippa; Evans, Chris; Grayson, Richard

2016-04-01

A long-term field trial was conducted on a blanket peatland in North Wales. Twelve ditches were studied. After an initial monitoring period, eight of the ditches had peat dams installed a few metres apart along their entire length (dammed), four of these ditches were also partially infilled through bank reprofiling (reprofiled). Four ditches were left open with no dams or reprofiling (open). These 12 ditches and the surrounding peat were then monitored for a further 4 years. The effect of ditch blocking on local water tables was spatially highly variable but small overall (of the order of 2-3 cm) because the site, despite having ditches, already had relatively shallow water tables (medians within the upper 10 cm of the peat profile). An initial five-fold reduction in discharge occurred in ditches that had been dammed or reprofiled. However, there was evidence of a slow change over time in ditch flow at the site in subsequent years, with the overall volume of water leaving the dammed or reprofiled ditch weirs increasing per unit of rainfall to around twice that which occurred in the first year after the restoration. These changes were not observed in the open ditches. There was therefore clear evidence of the benefits of long-term monitoring as hydrological impacts in the first year after ditch blocking were very different from those in later years as the site conditions gradually changed. The additional water that flowed in later periods of the study from the blocked ditch catchments occurred in the form of a more continuously-flowing baseflow with fewer dry periods. The cause of this increase was related to changes in subsurface flow pathways in the peat in the aftermath of re-wetting. We show that these subsurface pathways mean that even in sloping blanket peatlands, the catchment areas for peatland ditches may be very different from that expressed by surface topography alone. Therefore, peatland studies that have estimated aerially-weighted water or carbon fluxes from one or two open or blocked ditches and where such data have also been used in upscaling estimates, need to be treated with caution.

Elastomeric Capture Microparticles (ECmuPs) and Their use with Acoustophoresis to Perform Affinity Capture Assays

NASA Astrophysics Data System (ADS)

Cushing, Kevin Wallace

This dissertation describes the development of elastomeric capture microparticles (ECmicroPs) and their use with acoustophoresis to perform affinity capture assays. ECμPs that function as negative acoustic contrast particles were developed by crosslinking emulsion-based droplets composed of commercially available silicone precursors followed by functionalization with avidin/biotin reagents. The size distribution of the ECμPs was very broad or narrow depending on the emulsion system that was used during the synthesis process. Elastomeric particles exhibited a very broad size distribution when a bulk-emulsion process was used; however, when microfluidic systems were utilized, their size distribution became comparatively narrow. The functionalization of elastomeric particles was accomplished by the non-specific adsorption of avidin protein followed by bovine serum albumin (BSA) blocking and bio-specific adsorption of a biotinylated-capture antibody. Polydisperse ECμPs were functionalized to bind prostate specific antigen (PSA) or IgG-phycoerythrin (PE) in aqueous media (buffer, plasma, blood); whereas monodisperse ECμPs were functionalized to bind a high density lipoprotein in the aqueous media. Polydisperse ECμPs functionalized to bind PSA in a physiological buffer (PBS pH 7.4) demonstrated nanomolar detection using flow cytometry analysis; whereas ECμPs functionalized to bind IgG-PE demonstrated picomolar detection in 10% porcine plasma. ECμPs have a specific density of ~1.03 and are more compressible than their surrounding aqueous media; which allowed the ECμPs to exhibit negative acoustic contrast properties under an ultrasonic acoustic standing wave field. The negative acoustic contrast property of ECμPs was advantageously utilized in an IgG-PE assay conducted in 0.1% whole porcine blood. The ligand-bound ECμPs suspended in the diluted blood sample were flowed through an acoustofluidic device where the application of an ultrasonic acoustic standing wave field focused the ligand-bound ECμPs to pressure antinodes and the positive acoustic contrast blood cells to the central pressure node of the microchannel. As a result of laminar flow, focused ligand-bound ECμPs and blood cells were flowed into properly aligned outlet channels at the downstream trifurcation, where they where collected separately off-chip. The cell-free fraction containing ligand-bound ECμPs was analyzed using flow cytometry; where the detection of IgG-PE was in the picomolar range. This approach has potential applications in the development of rapid assays that detect the presence of low concentrations of biomarkers in a number of biological sample types.

Dynamic analysis of pedestrian crossing behaviors on traffic flow at unsignalized mid-block crosswalks

NASA Astrophysics Data System (ADS)

Liu, Gang; He, Jing; Luo, Zhiyong; Yang, Wunian; Zhang, Xiping

2015-05-01

It is important to study the effects of pedestrian crossing behaviors on traffic flow for solving the urban traffic jam problem. Based on the Nagel-Schreckenberg (NaSch) traffic cellular automata (TCA) model, a new one-dimensional TCA model is proposed considering the uncertainty conflict behaviors between pedestrians and vehicles at unsignalized mid-block crosswalks and defining the parallel updating rules of motion states of pedestrians and vehicles. The traffic flow is simulated for different vehicle densities and behavior trigger probabilities. The fundamental diagrams show that no matter what the values of vehicle braking probability, pedestrian acceleration crossing probability, pedestrian backing probability and pedestrian generation probability, the system flow shows the "increasing-saturating-decreasing" trend with the increase of vehicle density; when the vehicle braking probability is lower, it is easy to cause an emergency brake of vehicle and result in great fluctuation of saturated flow; the saturated flow decreases slightly with the increase of the pedestrian acceleration crossing probability; when the pedestrian backing probability lies between 0.4 and 0.6, the saturated flow is unstable, which shows the hesitant behavior of pedestrians when making the decision of backing; the maximum flow is sensitive to the pedestrian generation probability and rapidly decreases with increasing the pedestrian generation probability, the maximum flow is approximately equal to zero when the probability is more than 0.5. The simulations prove that the influence of frequent crossing behavior upon vehicle flow is immense; the vehicle flow decreases and gets into serious congestion state rapidly with the increase of the pedestrian generation probability.

STRUCTURAL CAPABILITIES OF NO-DIG MANHOLE REHABILITATION (WE&RF Report INFR1R12)

EPA Science Inventory

Failure of a manhole may have catastrophic consequences such as a sinkhole. At a minimum, wastewater flow will be blocked and flow upstream of the manhole will backup, causing a sanitary sewer overflow (SSO). Accordingly, the structural condition of a manhole is an important perf...

Restoration of Bladder and Bowel Function Using Electrical Stimulation and Block after Spinal Cord Injury

DTIC Science & Technology

2016-10-01

AWARD NUMBER: W81XWH-14-2-0132 TITLE: Restoration of Bladder and Bowel Function Using Electrical Stimulation and Block after Spinal Cord Injury...per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and...COVERED 29 Sep 2015 - 28 Sep 2016 4. TITLE AND SUBTITLE Restoration of Bladder and Bowel Function Using Electrical Stimulation and Block after Spinal

Experimental and analytical study of close-coupled ventral nozzles for ASTOVL aircraft

NASA Technical Reports Server (NTRS)

Mcardle, Jack G.; Smith, C. Frederic

1990-01-01

Flow in a generic ventral nozzle system was studied experimentally and analytically with a block version of the PARC3D computational fluid dynamics program (a full Navier-Stokes equation solver) in order to evaluate the program's ability to predict system performance and internal flow patterns. For the experimental work a one-third-size model tailpipe with a single large rectangular ventral nozzle mounted normal to the tailpipe axis was tested with unheated air at steady-state pressure ratios up to 4.0. The end of the tailpipe was closed to simulate a blocked exhaust nozzle. Measurements showed about 5 1/2 percent flow-turning loss, reasonable nozzle performance coefficients, and a significant aftward axial component of thrust due to flow turning loss, reasonable nozzle performance coefficients, and a significant aftward axial component of thrust due to flow turning more than 90 deg. Flow behavior into and through the ventral duct is discussed and illustrated with paint streak flow visualization photographs. For the analytical work the same ventral system configuration was modeled with two computational grids to evaluate the effect of grid density. Both grids gave good results. The finer-grid solution produced more detailed flow patterns and predicted performance parameters, such as thrust and discharge coefficient, within 1 percent of the measured values. PARC3D flow visualization images are shown for comparison with the paint streak photographs. Modeling and computational issues encountered in the analytical work are discussed.

Toward best practices for developing regional connectivity maps.

PubMed

Beier, Paul; Spencer, Wayne; Baldwin, Robert F; McRae, Brad H

2011-10-01

To conserve ecological connectivity (the ability to support animal movement, gene flow, range shifts, and other ecological and evolutionary processes that require large areas), conservation professionals need coarse-grained maps to serve as decision-support tools or vision statements and fine-grained maps to prescribe site-specific interventions. To date, research has focused primarily on fine-grained maps (linkage designs) covering small areas. In contrast, we devised 7 steps to coarsely map dozens to hundreds of linkages over a large area, such as a nation, province, or ecoregion. We provide recommendations on how to perform each step on the basis of our experiences with 6 projects: California Missing Linkages (2001), Arizona Wildlife Linkage Assessment (2006), California Essential Habitat Connectivity (2010), Two Countries, One Forest (northeastern United States and southeastern Canada) (2010), Washington State Connected Landscapes (2010), and the Bhutan Biological Corridor Complex (2010). The 2 most difficult steps are mapping natural landscape blocks (areas whose conservation value derives from the species and ecological processes within them) and determining which pairs of blocks can feasibly be connected in a way that promotes conservation. Decision rules for mapping natural landscape blocks and determining which pairs of blocks to connect must reflect not only technical criteria, but also the values and priorities of stakeholders. We recommend blocks be mapped on the basis of a combination of naturalness, protection status, linear barriers, and habitat quality for selected species. We describe manual and automated procedures to identify currently functioning or restorable linkages. Once pairs of blocks have been identified, linkage polygons can be mapped by least-cost modeling, other approaches from graph theory, or individual-based movement models. The approaches we outline make assumptions explicit, have outputs that can be improved as underlying data are improved, and help implementers focus strictly on ecological connectivity. ©2011 Society for Conservation Biology.

Peripheral vascular effects of bretylium tosylate in man.

PubMed

Blair, D A; Glover, W E; Kidd, B S; Roddie, I C

1960-09-01

After intra-arterial infusion of bretylium tosylate (12.5 mg.), the reflex changes in vasoconstrictor tone which normally occur in the forearm with body cooling, positive pressure breathing, the Valsalva manoeuvre and postural change were greatly reduced or abolished. Reflex vasodilatation mediated by cholinergic fibres in response to body heating or to emotional stress was little affected. It was concluded that bretylium can selectively block the activity of sympathetic noradrenergic fibres without causing a similar block of sympathetic cholinergic fibres. As the responses to intravenous or intra-arterial infusions of adrenaline or noradrenaline were not reduced after bretylium, it was concluded that bretylium interferes with the activity of noradrenergic fibres rather than with the activity of the noradrenaline released at the nerve ending. After bretylium infusion, forearm and hand blood flow did not often rise to levels characteristic of full release of vasoconstrictor tone. As infusion of bretylium into a nerve-blocked forearm resulted in a pronounced reduction in flow, it is concluded that bretylium also has a constrictor effect on blood vessels. The state of the vessels following an infusion of bretylium appears to depend on the balance between this constrictor action and the longer-acting sympathetic blocking effect.

Assessment of Surrogate Fractured Rock Networks for Evidence of Complex Behavior

NASA Astrophysics Data System (ADS)

Wood, T. R.; McJunkin, T. R.; Podgorney, R. K.; Glass, R. J.; Starr, R. C.; Stoner, D. L.; Noah, K. S.; LaViolette, R. A.; Fairley, J.

2001-12-01

A complex system or complex process is -"one whose properties are not fully explained by an understanding of its component parts". Results from field experiments conducted at the Hell's Half-Acre field site (Arco, Idaho) suggest that the flow of water in an unsaturated, fractured medium exhibits characteristics of a complex process. A series of laboratory studies is underway with sufficient rigor to determine if complex behavior observed in the field is in fact a fundamental characteristic of water flow in unsaturated, fractured media. As an initial step, a series of four duplicate experiments has been performed using an array of bricks to simulate fractured, unsaturated media. The array consisted of 12 limestone blocks cut to uniform size (5cm x 7 cm x 30 cm) stacked on end 4 blocks wide and 3 blocks high with the interfaces between adjacent blocks representing 3 vertical fractures intersecting 2 horizontal fractures. Water was introduced at three point sources on the upper boundary of the model at the top of the vertical fractures. Water was applied under constant flux at a rate below the infiltration capacity of the system, thus maintaining unsaturated flow conditions. Water was collected from the lower boundary via fiberglass wicks at the bottom of each fracture. An automated system acquired and processed water inflow and outflow data and time-lapse photographic data during each of the 72-hour tests. From these experiments, we see that a few general statements can be made on the overall advance of the wetting front in the surrogate fracture networks. For instance, flow generally converged with depth to the center fracture in the bottom row of bricks. Another observation is that fracture intersections integrate the steady flow in overlying vertical fractures and allow or cause short duration high discharge pulses or "avalanches" of flow to quickly traverse the fracture network below. Smaller scale tests of single fracture and fracture intersections are underway to evaluate a wide array of unit processes that are believed to contribute to complex behavior. Examples of these smaller scale experiments include the role of fracture intersections in integrating a steady inflow to generate giant fluctuations in network discharge; the influence of microbe growth on flow; and the role of geochemistry in alterations of flow paths. Experiments are planned at the meso and field scale to document and understand the controls on self-organized behavior. Modeling is being conducted in parallel with the experiments to understand how simulations can be improved to capture the complexity of fluid flow in fractured rock vadose zones and to make better predictions of contaminant transport.

Automated extraction of temporal motor activity signals from video recordings of neonatal seizures based on adaptive block matching.

PubMed

Karayiannis, Nicolaos B; Sami, Abdul; Frost, James D; Wise, Merrill S; Mizrahi, Eli M

2005-04-01

This paper presents an automated procedure developed to extract quantitative information from video recordings of neonatal seizures in the form of motor activity signals. This procedure relies on optical flow computation to select anatomical sites located on the infants' body parts. Motor activity signals are extracted by tracking selected anatomical sites during the seizure using adaptive block matching. A block of pixels is tracked throughout a sequence of frames by searching for the most similar block of pixels in subsequent frames; this search is facilitated by employing various update strategies to account for the changing appearance of the block. The proposed procedure is used to extract temporal motor activity signals from video recordings of neonatal seizures and other events not associated with seizures.

Twenty Years of "Plug-and-Pond" Meadow Restoration: A Geomorphic Review

NASA Astrophysics Data System (ADS)

Natali, J.

2015-12-01

Channel incision has degraded the ecological function of wet meadows across montane regions of California. Conservation groups estimate that half of the Sierra Nevada's 333,000 acres of meadow are entrenched in a degraded state that is characterized by a shift from groundwater­fed, herbaceous vegetation to more sparse, drought­tolerant woody vegetation. My poster will present results of field research on a prominent restoration technique in California's montane meadows, the "Plug­and­Pond." Fundamentally, the technique re­channelizes the meadow by blocking flow into incised stream channels. Spoils dug from meadow sediments plug the incised channel, creating ponds as a by­product. One of three approaches to re­channelization ensues: (1) construct a new shallow and sinuous channel, (2) redirect flows into a remnant channel, (3) or allow the channel to define itself over the meadow floodplain. Re­ channelization aims to support overbank flows at 1.5 to 3 year recurrence intervals. Field surveys of ten of the oldest "plug-and-pond" meadow restoration projects in California reveal that channel bed degradation caused by meadow-scale changes to channel slope (i.e. culverts concentrating flows, channel straightening, meadow grazing) may be more conducive to intensive restoration approaches like Plug-and-Pond.

The roles of cerebral blood flow, capillary transit time heterogeneity, and oxygen tension in brain oxygenation and metabolism

PubMed Central

Jespersen, Sune N; Østergaard, Leif

2012-01-01

Normal brain function depends critically on moment-to-moment regulation of oxygen supply by the bloodstream to meet changing metabolic needs. Neurovascular coupling, a range of mechanisms that converge on arterioles to adjust local cerebral blood flow (CBF), represents our current framework for understanding this regulation. We modeled the combined effects of CBF and capillary transit time heterogeneity (CTTH) on the maximum oxygen extraction fraction (OEFmax) and metabolic rate of oxygen that can biophysically be supported, for a given tissue oxygen tension. Red blood cell velocity recordings in rat brain support close hemodynamic–metabolic coupling by means of CBF and CTTH across a range of physiological conditions. The CTTH reduction improves tissue oxygenation by counteracting inherent reductions in OEFmax as CBF increases, and seemingly secures sufficient oxygenation during episodes of hyperemia resulting from cortical activation or hypoxemia. In hypoperfusion and states of blocked CBF, both lower oxygen tension and CTTH may secure tissue oxygenation. Our model predicts that disturbed capillary flows may cause a condition of malignant CTTH, in which states of higher CBF display lower oxygen availability. We propose that conditions with altered capillary morphology, such as amyloid, diabetic or hypertensive microangiopathy, and ischemia–reperfusion, may disturb CTTH and thereby flow-metabolism coupling and cerebral oxygen metabolism. PMID:22044867

WATER PROCESS SYSTEM FLOW DIAGRAM FOR MTR, TRA603. SUMMARY OF ...

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

WATER PROCESS SYSTEM FLOW DIAGRAM FOR MTR, TRA-603. SUMMARY OF COOLANT FLOW FROM WORKING RESERVOIR TO INTERIOR OF REACTOR'S THERMAL SHIELD. NAMES TANK SECTIONS. PIPE AND DRAIN-LINE SIZES. SHOWS DIRECTION OF AIR FLOW THROUGH PEBBLE AND GRAPHITE BLOCK ZONE. NEUTRON CURTAIN AND THERMAL COLUMN DOOR. BLAW-KNOX 3150-92-7, 3/1950. INL INDEX NO. 531-0603-51-098-100036, REV. 6. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Investigation of flows in LAPD and their relation to edge turbulence and intermittency

NASA Astrophysics Data System (ADS)

Schaffner, D.; Carter, T. A.; Friedman, B.; Vincena, S.; Auerbach, D. W.; Popovich, P.

2009-11-01

We report on measurements of spontaneous flows and turbulence in the Large Plasma Device (LAPD) at UCLA. Measurements of perpendicular and parallel flow using a six-sided Mach probe reveal edge-localized perpendicular flows. The source of this flow is under investigation and may be generated by boundary effects or turbulent processes. Particular cases where a plasma depletion zone is created, including inserting a blocking disk within the cathode region and forming a compressed column, are used to analyze the effects on plasma flows. Ultimately, the relationship between the flows, turbulence and intermittency---the formation of blobs---is sought.

An in vitro study of magnetic particle targeting in small blood vessels

NASA Astrophysics Data System (ADS)

Udrea, Laura Elena; Strachan, Norval J. C.; Bădescu, Vasile; Rotariu, Ovidiu

2006-10-01

The magnetic guidance and capture of particles inside the human body, via the circulatory system, is a novel method for the targeted delivery of drugs. This experimental study confirms in vitro that a dipolar capturing device, based on high-energy magnets with an active space of 8.7 cm × 10 cm × 10 cm, retains colloidal magnetic particles (MPs) (<30 nm) injected in the capillary tubes, where flow velocities are comparable to that encountered in the capillary beds of tumours (<0.5 cm s-1). The build-up of the deposition of the MPs was investigated using video imaging techniques that enabled continuous monitoring of the blocking of the vessel whilst simultaneously recording the colloid's flow rate. The parameters of practical importance (length of MP deposit, time of capillary blocking) were estimated and were found to be dependent on the initial fluid velocity, the MP concentration and the distance between the capillary tube and the polar magnetic pieces. Although the tube used in this experiment is larger (diameter = 0.75 mm, length = 100 mm) than that of real capillaries (diameter = 0.01 mm, length ~1.5 mm), the flow velocities chosen were similar to those encountered in the capillary beds of tumours and the length/diameter ratio was approximately equal (133 for the present set-up, 100-150 for real capillaries). In these circumstances and using the same magnetic field conditions (intensity, gradient) and MPs, there is close similarity with magnetic capture in a microscopic capillary system. Moreover, the macroscopic system permits analysis of the distribution of MPs in the active magnetic space, and consequently the maximum targetable volume. This study revealed that the capture of particles within the active space was strongly influenced by the gradient of the magnetic field and the flow velocity. Thus, when the magnetic field gradient had medium values (0.1-0.3 T cm-1) and the fluid velocity was small (0.15 cm s-1), the particles were captured in small, compact and stable deposits (L < 4 cm) and the time necessary for blocking of the capillary was <150 s. Doubling the value for the flow velocity did not influence significantly either the length of MP deposits nor the blocking time. However, lower gradients (<0.1 T cm-1) and larger velocities (0.3-0.9 cm s-1) result in the formation of larger deposits (4 cm < L < 10 cm) that are unstable at the beginning of the capture process. These large deposits do become stable given sufficient time for the deposition process to take place in conjunction with a decrease in the flow rate. As a consequence, the time necessary for blocking of the capillary increased up to 450 s. Decreasing the MP concentration from 0.02 g cm-3 to 0.005 g cm-3 decreased the deposit lengths by approximately 20% and doubled the values of the blocking time. The maximum targetable volume obtained by the present method is ~350 cm3, which corresponds to medium-sized tumours. The capillary vessels were blocked only for the situation that occurs for microcirculation within a tumour. This reduces the concentration of MPs trapped within the normal tissues, which occurs when using particles of micrometre size. This work showed the potential of using colloidal MPs and dipolar magnetic devices for treatment of human patients, when the affected sites are positioned at medium distances from the surface of the body (e.g. head, neck, breast, hands and legs).

Blackbody emission from light interacting with an effective moving dispersive medium.

PubMed

Petev, M; Westerberg, N; Moss, D; Rubino, E; Rimoldi, C; Cacciatori, S L; Belgiorno, F; Faccio, D

2013-07-26

Intense laser pulses excite a nonlinear polarization response that may create an effective flowing medium and, under appropriate conditions, a blocking horizon for light. Here, we analyze in detail the interaction of light with such laser-induced flowing media, fully accounting for the medium dispersion properties. An analytical model based on a first Born approximation is found to be in excellent agreement with numerical simulations based on Maxwell's equations and shows that when a blocking horizon is formed, the stimulated medium scatters light with a blackbody emission spectrum. Based on these results, diamond is proposed as a promising candidate medium for future studies of Hawking emission from artificial, dispersive horizons.

Parquet: Regions of areal plastic dislocations (on Venus)

NASA Technical Reports Server (NTRS)

Sukhanov, A. L.

1986-01-01

The extensive flat elevations of the Northern Hemisphere of Venus are covered with frequently intersecting lines of dislocations, resembling the outline of a giant parquet. In the internal sections of these regions we find grabens and regions of extension, and on the periphery lobe-shaped flow structures. The parquet was formed after the beginning of the formation of the lava plains, but covered by the youngest lava. These structures apparently arose partly because of the dragging of blocks of crust by the asthenospheric flows, and partly in the gravitational sliding of such heated blocks in the partial melting of their base. It is possible that these elevations occupy on Venus the place of the Earth's rift systems.

Canonical forms of multidimensional steady inviscid flows

NASA Technical Reports Server (NTRS)

Taasan, Shlomo

1993-01-01

Canonical forms and canonical variables for inviscid flow problems are derived. In these forms the components of the system governed by different types of operators (elliptic and hyperbolic) are separated. Both the incompressible and compressible cases are analyzed, and their similarities and differences are discussed. The canonical forms obtained are block upper triangular operator form in which the elliptic and non-elliptic parts reside in different blocks. The full nonlinear equations are treated without using any linearization process. This form enables a better analysis of the equations as well as better numerical treatment. These forms are the analog of the decomposition of the one dimensional Euler equations into characteristic directions and Riemann invariants.

Investigation of flow turning phenomenon - Effect of upstream and downstream propagation

NASA Astrophysics Data System (ADS)

Baum, Joseph D.

1988-01-01

Upstream acoustic-wave propagation in flow injected laterally through the boundary layer of a tube (simulating the flow in a solid-rocket motor) is investigated analytically. A noniterative linearized-block implicit scheme is used to solve the time-dependent compressible Navier-Stokes equations, and the results are presented in extensive graphs and characterized. Acoustic streaming interaction is shown to be significantly greater for upstream than for downstream propagation.

Modelling Detailed-Chemistry Effects on Turbulent Diffusion Flames using a Parallel Solution-Adaptive Scheme

NASA Astrophysics Data System (ADS)

Jha, Pradeep Kumar

Capturing the effects of detailed-chemistry on turbulent combustion processes is a central challenge faced by the numerical combustion community. However, the inherent complexity and non-linear nature of both turbulence and chemistry require that combustion models rely heavily on engineering approximations to remain computationally tractable. This thesis proposes a computationally efficient algorithm for modelling detailed-chemistry effects in turbulent diffusion flames and numerically predicting the associated flame properties. The cornerstone of this combustion modelling tool is the use of parallel Adaptive Mesh Refinement (AMR) scheme with the recently proposed Flame Prolongation of Intrinsic low-dimensional manifold (FPI) tabulated-chemistry approach for modelling complex chemistry. The effect of turbulence on the mean chemistry is incorporated using a Presumed Conditional Moment (PCM) approach based on a beta-probability density function (PDF). The two-equation k-w turbulence model is used for modelling the effects of the unresolved turbulence on the mean flow field. The finite-rate of methane-air combustion is represented here by using the GRI-Mech 3.0 scheme. This detailed mechanism is used to build the FPI tables. A state of the art numerical scheme based on a parallel block-based solution-adaptive algorithm has been developed to solve the Favre-averaged Navier-Stokes (FANS) and other governing partial-differential equations using a second-order accurate, fully-coupled finite-volume formulation on body-fitted, multi-block, quadrilateral/hexahedral mesh for two-dimensional and three-dimensional flow geometries, respectively. A standard fourth-order Runge-Kutta time-marching scheme is used for time-accurate temporal discretizations. Numerical predictions of three different diffusion flames configurations are considered in the present work: a laminar counter-flow flame; a laminar co-flow diffusion flame; and a Sydney bluff-body turbulent reacting flow. Comparisons are made between the predicted results of the present FPI scheme and Steady Laminar Flamelet Model (SLFM) approach for diffusion flames. The effects of grid resolution on the predicted overall flame solutions are also assessed. Other non-reacting flows have also been considered to further validate other aspects of the numerical scheme. The present schemes predict results which are in good agreement with published experimental results and reduces the computational cost involved in modelling turbulent diffusion flames significantly, both in terms of storage and processing time.

Single-molecule tracking studies of flow-induced microdomain alignment in cylinder-forming polystyrene-poly(ethylene oxide) diblock copolymer films.

PubMed

Tran-Ba, Khanh-Hoa; Higgins, Daniel A; Ito, Takashi

2014-09-25

Flow-based approaches are promising routes to preparation of aligned block copolymer microdomains within confined spaces. An in-depth characterization of such nanoscale morphologies within macroscopically nonuniform materials under ambient conditions is, however, often challenging. In this study, single-molecule tracking (SMT) methods were employed to probe the flow-induced alignment of cylindrical microdomains (ca. 22 nm in diameter) in polystyrene-poly(ethylene oxide) diblock copolymer (PS-b-PEO) films. Films of micrometer-scale thicknesses were prepared by overlaying a benzene solution droplet on a glass coverslip with a rectangular glass plate, followed by solvent evaporation under a nitrogen atmosphere. The microdomain alignment was quantitatively assessed from SMT data exhibiting the diffusional motions of individual sulforhodamine B fluorescent probes that preferentially partitioned into cylindrical PEO microdomains. Better overall microdomain orientation along the flow direction was observed near the substrate interface in films prepared at a higher flow rate, suggesting that the microdomain alignment was primarily induced by shear flow. The SMT data also revealed the presence of micrometer-scale grains consisting of highly ordered microdomains with coherent orientation. The results of this study provide insights into shear-based preparation of aligned cylindrical microdomains in block copolymer films from solutions within confined spaces.

I-domain of lymphocyte function-associated antigen-1 mediates rolling of polystyrene particles on ICAM-1 under flow.

PubMed

Eniola, A Omolola; Krasik, Ellen F; Smith, Lee A; Song, Gang; Hammer, Daniel A

2005-11-01

In their active state, beta(2)-integrins, such as LFA-1, mediate the firm arrest of leukocytes by binding intercellular adhesion molecules (ICAMs) expressed on endothelium. Although the primary function of LFA-1 is assumed to be the ability to mediate firm adhesion, recent work has shown that LFA-1 can contribute to cell tethering and rolling under hydrodynamic flow, a role previously largely attributed to the selectins. The inserted (I) domain of LFA-1 has recently been crystallized in the wild-type (wt) and locked-open conformations and has been shown to, respectively, support rolling and firm adhesion under flow when expressed in alpha(L)beta(2) heterodimers or as isolated domains on cells. Here, we report results from cell-free adhesion assays where wt I-domain-coated polystyrene particles were allowed to interact with ICAM-1-coated surfaces in shear flow. We show that wt I-domain can independently mediate the capture of particles from flow and support their rolling on ICAM-1 surfaces in a manner similar to how carbohydrate-selectin interactions mediate rolling. Adhesion is specific and blocked by appropriate antibodies. We also show that the rolling velocity of I-domain-coated particles depends on the wall shear stress in flow chamber, I-domain site density on microsphere surfaces, and ICAM-1 site density on substrate surfaces. Furthermore, we show that rolling is less sensitive to wall shear stress and ICAM-1 substrate density at high density of I-domain on the microsphere surface. Computer simulations using adhesive dynamics can recreate bead rolling dynamics and show that the mechanochemical properties of ICAM-1-I-domain interactions are similar to those of carbohydrate-selectin interactions. Understanding the biophysics of adhesion mediated by the I-domain of LFA-1 can elucidate the complex roles this integrin plays in leukocyte adhesion in inflammation.

Mast cells in Waldenstrom's macroglobulinemia support lymphoplasmacytic cell growth through CD154/CD40 signaling.

PubMed

Tournilhac, O; Santos, D D; Xu, L; Kutok, J; Tai, Y-T; Le Gouill, S; Catley, L; Hunter, Z; Branagan, A R; Boyce, J A; Munshi, N; Anderson, K C; Treon, S P

2006-08-01

Bone marrow (BM) mast cells (MC) are commonly found in association with lymphoplasmacytic cells (LPC) in patients with Waldenström's macroglobulinemia (WM). We therefore sought to clarify the role of MC in WM. Co-culture of sublethally irradiated HMC-1 MC, KU812 basophilic cells, or autologous BM MC along with BM LPC from WM patients resulted in MC dose-dependent tumor colony formation and/or proliferation as assessed by 3H-thymidine uptake studies. Furthermore, by immunohistochemistry, multicolor flow cytometry and/or RT-PCR analysis, CD40 ligand (CD154), a potent inducer of B-cell expansion, was expressed on BM MC from 32 of 34 (94%), 11 of 13 (85%), and 7 of 9 (78%) patients, respectively. In contrast, MC from five healthy donors did not express CD154. By multicolor flow cytometry, CD154 was expressed on BM LPC from 35 of 38 (92%) patients and functionality was confirmed by CD154 and CD40 agonistic antibody stimulation, which induced proliferation, support survival and/or pERK phosphorylation of LPC. Moreover, MC induced expansion of LPC from 3 of 5 patients was blocked in a dose dependent manner by use of a CD154 blocking protein. These studies demonstrate that in WM, MC may support tumor cell expansion through constitutive CD154-CD40 signaling and therefore provide the framework for therapeutic targeting of MC and MC-WM cell interactions in WM.

Transport toward a well in highly heterogeneous aquifer

NASA Astrophysics Data System (ADS)

Di Dato, Mariaines; de Barros, Felipe P. J.; Bellin, Alberto; Fiori, Aldo

2017-04-01

Solute transport toward a well is a challenging subject in subsurface hydrology since the complexity of the mathematical model is tremendously increased by the non-uniformity of the mean flow and heterogeneity of the formation. Up to date, analytical solutions for such flow configurations are limited to low heterogeneous conditions. On the other hand, numerical simulations in 3D highly heterogeneous formations are computationally expensive and plagued by numerical errors. In this work we propose an analytical solution for the Breakthrough Curve (BTC) at the well for an instantaneous linear injection across the aquifer's thickness for any degree of heterogeneity of the porous medium. Our solution makes use of the Multi Indicator Model-Self Consistent Approximation (MIMSCA), by which the aquifer is conceptualized as an ensemble of blocks of constant hydraulic conductivity K randomly drawn from a lognormal distribution. In order to apply MIMSCA, we assume the flow as locally uniform, given that K is uniform within the block. With this approximation, the travel time to the well is equal to the superposition of the time spent by the solute particle within each block. We emphasize that, despite the approximations introduced, the model is able to reproduce the laboratory experiment of [1] without the need to fit any transport parameters. In this work, we present results for two different injection modes: a resident injection (e.g., residual DNAPL) and a flux proportional injection (e.g., leakage from a passive well). The proposed methodology allows to quantify the BTC at the well as a function of few parameters such as the injection mode and the statistical structure of the aquifer (geometric mean, variance and integral scale of the hydraulic conductivity field). Results illustrate that the release condition has a strong impact on the shape of the BTC. Furthermore, the difference between different injection modes increases with the heterogeneity of the K-field. The importance of the both injection mode and heterogeneity degree are also elucidated on the early and late solute arrival times at the well. Finally, we show how travel times become ergodic only for very thick aquifers, even in case of mild heterogeneity. We emphasize that the present framework has a practical validity, giving an affordable, although approximated, first estimation of mass arrival at an extraction well. References [1] Fernàndez-Garcia, D., T. H. Illangasekare, and H. Rajaram (2004), Conservative and sorptive forced-gradient and uniform flow tracer tests in a three-dimensional laboratory test aquifer, Water Resour. Res., 40, W10103, doi:10.1029/2004WR003112.

Algorithms for parallel flow solvers on message passing architectures

NASA Technical Reports Server (NTRS)

Vanderwijngaart, Rob F.

1995-01-01

The purpose of this project has been to identify and test suitable technologies for implementation of fluid flow solvers -- possibly coupled with structures and heat equation solvers -- on MIMD parallel computers. In the course of this investigation much attention has been paid to efficient domain decomposition strategies for ADI-type algorithms. Multi-partitioning derives its efficiency from the assignment of several blocks of grid points to each processor in the parallel computer. A coarse-grain parallelism is obtained, and a near-perfect load balance results. In uni-partitioning every processor receives responsibility for exactly one block of grid points instead of several. This necessitates fine-grain pipelined program execution in order to obtain a reasonable load balance. Although fine-grain parallelism is less desirable on many systems, especially high-latency networks of workstations, uni-partition methods are still in wide use in production codes for flow problems. Consequently, it remains important to achieve good efficiency with this technique that has essentially been superseded by multi-partitioning for parallel ADI-type algorithms. Another reason for the concentration on improving the performance of pipeline methods is their applicability in other types of flow solver kernels with stronger implied data dependence. Analytical expressions can be derived for the size of the dynamic load imbalance incurred in traditional pipelines. From these it can be determined what is the optimal first-processor retardation that leads to the shortest total completion time for the pipeline process. Theoretical predictions of pipeline performance with and without optimization match experimental observations on the iPSC/860 very well. Analysis of pipeline performance also highlights the effect of uncareful grid partitioning in flow solvers that employ pipeline algorithms. If grid blocks at boundaries are not at least as large in the wall-normal direction as those immediately adjacent to them, then the first processor in the pipeline will receive a computational load that is less than that of subsequent processors, magnifying the pipeline slowdown effect. Extra compensation is needed for grid boundary effects, even if all grid blocks are equally sized.

Evaluation of WRF Simulations With Different Selections of Subgrid Orographic Drag Over the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Zhou, X.; Beljaars, A.; Wang, Y.; Huang, B.; Lin, C.; Chen, Y.; Wu, H.

2017-09-01

Weather Research and Forecasting (WRF) simulations with different selections of subgrid orographic drag over the Tibetan Plateau have been evaluated with observation and ERA-Interim reanalysis. Results show that the subgrid orographic drag schemes, especially the turbulent orographic form drag (TOFD) scheme, efficiently reduce the 10 m wind speed bias and RMS error with respect to station measurements. With the combination of gravity wave, flow blocking and TOFD schemes, wind speed is simulated more realistically than with the individual schemes only. Improvements are also seen in the 2 m air temperature and surface pressure. The gravity wave drag, flow blocking drag, and TOFD schemes combined have the smallest station mean bias (-2.05°C in 2 m air temperature and 1.27 hPa in surface pressure) and RMS error (3.59°C in 2 m air temperature and 2.37 hPa in surface pressure). Meanwhile, the TOFD scheme contributes more to the improvements than the gravity wave drag and flow blocking schemes. The improvements are more pronounced at low levels of the atmosphere than at high levels due to the stronger drag enhancement on the low-level flow. The reduced near-surface cold bias and high-pressure bias over the Tibetan Plateau are the result of changes in the low-level wind components associated with the geostrophic balance. The enhanced drag directly leads to weakened westerlies but also enhances the a-geostrophic flow in this case reducing (enhancing) the northerlies (southerlies), which bring more warm air across the Himalaya Mountain ranges from South Asia (bring less cold air from the north) to the interior Tibetan Plateau.

Unlocking Chain Exchange in Highly Amphiphilic Block Polymer Micellar Systems: Influence of Agitation.

PubMed

Murphy, Ryan P; Kelley, Elizabeth G; Rogers, Simon A; Sullivan, Millicent O; Epps, Thomas H

2014-11-18

Chain exchange between block polymer micelles in highly selective solvents, such as water, is well-known to be arrested under quiescent conditions, yet this work demonstrates that simple agitation methods can induce rapid chain exchange in these solvents. Aqueous solutions containing either pure poly(butadiene- b -ethylene oxide) or pure poly(butadiene- b -ethylene oxide- d 4 ) micelles were combined and then subjected to agitation by vortex mixing, concentric cylinder Couette flow, or nitrogen gas sparging. Subsequently, the extent of chain exchange between micelles was quantified using small angle neutron scattering. Rapid vortex mixing induced chain exchange within minutes, as evidenced by a monotonic decrease in scattered intensity, whereas Couette flow and sparging did not lead to measurable chain exchange over the examined time scale of hours. The linear kinetics with respect to agitation time suggested a surface-limited exchange process at the air-water interface. These findings demonstrate the strong influence of processing conditions on block polymer solution assemblies.

A Cephalometric Comparison of Twin Block and Bionator Appliances in Treatment of Class II Malocclusion

PubMed Central

Ahmadian-Babaki, Fatemeh; Araghbidi-Kashani, S. Mehdi

2017-01-01

Background Class II malocclusion is one of the most common orthodontic problems. In cases of class II malocclusion with mandibular deficiency, functional appliances often are used with the intent of stimulating mandibular growth. Bionator and twin block are two of the more popular functional appliances. The aim of this study was to compare the treatment outcomes of these two appliances using cephalometric radiographs. Material and Methods Cephalometric radiographs of 33 patients who had class II division I malocclusion, before and after treatment were digitalized. The mean changes in twin block and bionator groups were compared using independent t test. Results Twin block and bionator showed no statistically significant differences in cephalometric parameters except for ANB, NA-Pog, Basal and Ar-Go-Me angles. Conclusions There were no statistically significant differences in dentoalveolar and mandibular position between twin block and bionator (p>0.1). Twin block was more efficient in inhibition of forward movement of maxilla (p<0.1). Key words:Functional, Class II malocclusion, Cephalometrics, Twin block, Bionator, Treatment. PMID:28149473

Block copolymer adhesion promoters via ring-opening metathesis polymerization

DOEpatents

Kent, M.S.; Saunders, R.

1997-02-18

Coupling agents are disclosed based on functionalized block copolymers for bonding thermoset polymers to solid materials. These are polymers which possess at least two types of functional groups, one which is able to attach to and react with solid surfaces, and another which can react with a thermoset resin, which are incorporated as pendant groups in monomers distributed in blocks (typically two) along the backbone of the chain. The block copolymers in this invention are synthesized by living ring-opening metathesis polymerization. 18 figs.

Computer Programming Manual for the Jovial (J73) Language

DTIC Science & Technology

1981-06-01

in function is: C - BYTE("ABCDEFŕ ,2,3); The built-in function extracts "BCD" from the string "ABCDEF". ( - 9 - 1: introduction ’ Two of the built...Tabl,’ Declarations Oil -fIt Chapter 8 BLOCK DECLARATIONS A block groups items, tables, and other blocks into contiguous storage. A block also gives a...substring to be extracted starts. Length specifies the number of bits in the subetring. Bits in a bit string are numbered from left to right, beginning with

Block copolymer adhesion promoters via ring-opening metathesis polymerization

DOEpatents

Kent, Michael S.; Saunders, Randall

1997-01-01

Coupling agents based on functionalized block copolymers for bonding thermoset polymers to solid materials. These are polymers which possess at least two types of functional groups, one which is able to attach to and react with solid surfaces, and another which can react with a thermoset resin, which are incorporated as pendant groups in monomers distributed in blocks (typically two) along the backbone of the chain. The block copolymers in this invention are synthesized by living ring-opening metathesis polymerization.

Functionalized Helical Building Blocks for Nanoelectronics.

PubMed

Khokhlov, Khrystofor; Schuster, Nathaniel J; Ng, Fay; Nuckolls, Colin

2018-04-06

Molecular building blocks are designed and created for the cis- and trans-dibrominated perylenediimides. The syntheses are simple and provide these useful materials on the gram scale. To demonstrate their synthetic versatility, these building blocks were used to create new dimeric perylenediimide helixes. Two of these helical dimers are twistacenes, and one is a helicene. Crucially, each possesses regiochemically defined functionality that allows the dimer helix to be elaborated into higher oligomers. It would be very difficult to prepare these helical PDI building blocks regioselectively without the methods described.

Subaqueous rhyolite block lavas in the Miocene Ushikiri Formation, Shimane Peninsula, SW Japan

NASA Astrophysics Data System (ADS)

Kano, Kazuhiko; Takeuchi, Keiji; Yamamoto, Takahiro; Hoshizumi, Hideo

1991-06-01

A rhyolite mass of the Miocene Ushikiri Formation in the western part of the Shimane Peninsula, SW Japan, is a small subaqueous edifice about 600 m high and 4 km wide, formed at water depths between 200 and 1000 m. It consists mainly of three relatively flat, lava-flow units 50-300 m in maximum thickness, each of which includes lobes and their polyhedral fragments. The lava lobes are poorly to well vesiculated, glassy to microcrystalline and flow-banded and -folded. Compared with mafic pillows, they are large, having thick, quenched and brecciated, glassy crusts because of their high viscosity, surface tension and thermal conductivity. Their surfaces disintegrate into polyhedral fragments and grade into massive volcanic breccia. The massive volcanic breccia composed of the lobe fragments is poorly sorted and covered with stratified volcanic breccia of the same rock type. The rhyolite lavas commonly bifurcate in a manner similar to mafic pillow lavas. However, they are highly silicic with 1-5 vol.% phenocrysts and have elongated vesicles and flow-folds, implying that they were visco-plastic during flowage. Their surface features are similar to those of subaerial block lava. With respect to rheological and morphological features, they are subaqueous equivalents of block lava.

Diagnostic layer integration in FPGA-based pipeline measurement systems for HEP experiments

NASA Astrophysics Data System (ADS)

Pozniak, Krzysztof T.

2007-08-01

Integrated triggering and data acquisition systems for high energy physics experiments may be considered as fast, multichannel, synchronous, distributed, pipeline measurement systems. A considerable extension of functional, technological and monitoring demands, which has recently been imposed on them, forced a common usage of large field-programmable gate array (FPGA), digital signal processing-enhanced matrices and fast optical transmission for their realization. This paper discusses modelling, design, realization and testing of pipeline measurement systems. A distribution of synchronous data stream flows is considered in the network. A general functional structure of a single network node is presented. A suggested, novel block structure of the node model facilitates full implementation in the FPGA chip, circuit standardization and parametrization, as well as integration of functional and diagnostic layers. A general method for pipeline system design was derived. This method is based on a unified model of the synchronous data network node. A few examples of practically realized, FPGA-based, pipeline measurement systems were presented. The described systems were applied in ZEUS and CMS.

Meta-Optics

NASA Astrophysics Data System (ADS)

Engheta, Nader

2014-03-01

As the fields of metamaterial and plasmonic nanophotonics reach certain levels of development, new directions and novel vistas appear in the horizon. Modularization, parameterization and functionalization of metamaterials may be exploited to provide new functionalities and applications stemming from such interesting platforms of ``meta-optics.'' Indeed, the metamaterial ``forms'' may lead to novel ``functions.'' These may include metamaterial ``bits'' and ``bytes'' as building blocks for digitizing metamaterials, ``optical metatronics'' - metamaterial-inspired optical nanocircuitry - formed by judicious arrangement of nanostructures capable of optical processing at the nanoscale, ``meta-systems'' formed by metamaterials and metasurfaces providing wave-based signal handling and processing, graphene metatronics as one-atom-thick mid IR circuits, and nonreciprocal metastructures for unusual control over flow of photons, to name a few. We are exploring various features and characteristics of these concepts, topics, and directions in the paradigms of meta-optics and are investigating new classes of potential applications such paradigms may provide. We will present an overview of our most recent results from a sample of these topics and will discuss future directions and potentials.

Synapses and Memory Storage

PubMed Central

Mayford, Mark; Siegelbaum, Steven A.; Kandel, Eric R.

2012-01-01

The synapse is the functional unit of the brain. During the last several decades we have acquired a great deal of information on its structure, molecular components, and physiological function. It is clear that synapses are morphologically and molecularly diverse and that this diversity is recruited to different functions. One of the most intriguing findings is that the size of the synaptic response in not invariant, but can be altered by a variety of homo- and heterosynaptic factors such as past patterns of use or modulatory neurotransmitters. Perhaps the most difficult challenge in neuroscience is to design experiments that reveal how these basic building blocks of the brain are put together and how they are regulated to mediate the information flow through neural circuits that is necessary to produce complex behaviors and store memories. In this review we will focus on studies that attempt to uncover the role of synaptic plasticity in the regulation of whole-animal behavior by learning and memory. PMID:22496389

Blocking NMDA receptors delays death in rats with acute liver failure by dual protective mechanisms in kidney and brain.

PubMed

Cauli, Omar; González-Usano, Alba; Cabrera-Pastor, Andrea; Gimenez-Garzó, Carla; López-Larrubia, Pilar; Ruiz-Sauri, Amparo; Hernández-Rabaza, Vicente; Duszczyk, Malgorzata; Malek, Michal; Lazarewicz, Jerzy W; Carratalá, Arturo; Urios, Amparo; Miguel, Alfonso; Torregrosa, Isidro; Carda, Carmen; Montoliu, Carmina; Felipo, Vicente

2014-06-01

Treatment of patients with acute liver failure (ALF) is unsatisfactory and mortality remains unacceptably high. Blocking NMDA receptors delays or prevents death of rats with ALF. The underlying mechanisms remain unclear. Clarifying these mechanisms will help to design more efficient treatments to increase patient's survival. The aim of this work was to shed light on the mechanisms by which blocking NMDA receptors delays rat's death in ALF. ALF was induced by galactosamine injection. NMDA receptors were blocked by continuous MK-801 administration. Edema and cerebral blood flow were assessed by magnetic resonance. The time course of ammonia levels in brain, muscle, blood, and urine; of glutamine, lactate, and water content in brain; of glomerular filtration rate and kidney damage; and of hepatic encephalopathy (HE) and intracranial pressure was assessed. ALF reduces kidney glomerular filtration rate (GFR) as reflected by reduced inulin clearance. GFR reduction is due to both reduced renal perfusion and kidney tubular damage as reflected by increased Kim-1 in urine and histological analysis. Blocking NMDA receptors delays kidney damage, allowing transient increased GFR and ammonia elimination which delays hyperammonemia and associated changes in brain. Blocking NMDA receptors does not prevent cerebral edema or blood-brain barrier permeability but reduces or prevents changes in cerebral blood flow and brain lactate. The data show that dual protective effects of MK-801 in kidney and brain delay cerebral alterations, HE, intracranial pressure increase and death. NMDA receptors antagonists may increase survival of patients with ALF by providing additional time for liver transplantation or regeneration.

mTOR drives cerebral blood flow and memory deficits in LDLR-/- mice modeling atherosclerosis and vascular cognitive impairment.

PubMed

Jahrling, Jordan B; Lin, Ai-Ling; DeRosa, Nicholas; Hussong, Stacy A; Van Skike, Candice E; Girotti, Milena; Javors, Martin; Zhao, Qingwei; Maslin, Leigh Ann; Asmis, Reto; Galvan, Veronica

2018-01-01

We recently showed that mTOR attenuation blocks progression and abrogates established cognitive deficits in Alzheimer's disease (AD) mouse models. These outcomes were associated with the restoration of cerebral blood flow (CBF) and brain vascular density (BVD) resulting from relief of mTOR inhibition of NO release. Recent reports suggested a role of mTOR in atherosclerosis. Because mTOR drives aging and vascular dysfunction is a universal feature of aging, we hypothesized that mTOR may contribute to brain vascular and cognitive dysfunction associated with atherosclerosis. We measured CBF, BVD, cognitive function, markers of inflammation, and parameters of cardiovascular disease in LDLR -/- mice fed maintenance or high-fat diet ± rapamycin. Cardiovascular pathologies were proportional to severity of brain vascular dysfunction. Aortic atheromas were reduced, CBF and BVD were restored, and cognitive dysfunction was attenuated potentially through reduction in systemic and brain inflammation following chronic mTOR attenuation. Our studies suggest that mTOR regulates vascular integrity and function and that mTOR attenuation may restore neurovascular function and cardiovascular health. Together with our previous studies in AD models, our data suggest mTOR-driven vascular damage may be a mechanism shared by age-associated neurological diseases. Therefore, mTOR attenuation may have promise for treatment of cognitive impairment in atherosclerosis.

A novel visual hardware behavioral language

NASA Technical Reports Server (NTRS)

Li, Xueqin; Cheng, H. D.

1992-01-01

Most hardware behavioral languages just use texts to describe the behavior of the desired hardware design. This is inconvenient for VLSI designers who enjoy using the schematic approach. The proposed visual hardware behavioral language has the ability to graphically express design information using visual parallel models (blocks), visual sequential models (processes) and visual data flow graphs (which consist of primitive operational icons, control icons, and Data and Synchro links). Thus, the proposed visual hardware behavioral language can not only specify hardware concurrent and sequential functionality, but can also visually expose parallelism, sequentiality, and disjointness (mutually exclusive operations) for the hardware designers. That would make the hardware designers capture the design ideas easily and explicitly using this visual hardware behavioral language.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 6: Specification for EOS Central Data Processing Facility (CDPF)

NASA Technical Reports Server (NTRS)

1974-01-01

The specifications and functions of the Central Data Processing (CDPF) Facility which supports the Earth Observatory Satellite (EOS) are discussed. The CDPF will receive the EOS sensor data and spacecraft data through the Spaceflight Tracking and Data Network (STDN) and the Operations Control Center (OCC). The CDPF will process the data and produce high density digital tapes, computer compatible tapes, film and paper print images, and other data products. The specific aspects of data inputs and data processing are identified. A block diagram of the CDPF to show the data flow and interfaces of the subsystems is provided.

Digital autopilots: Design considerations and simulator evaluations

NASA Technical Reports Server (NTRS)

Osder, S.; Neuman, F.; Foster, J.

1971-01-01

The development of a digital autopilot program for a transport aircraft and the evaluation of that system's performance on a transport aircraft simulator is discussed. The digital autopilot includes three axis attitude stabilization, automatic throttle control and flight path guidance functions with emphasis on the mode progression from descent into the terminal area through automatic landing. The study effort involved a sequence of tasks starting with the definition of detailed system block diagrams of control laws followed by a flow charting and programming phase and concluding with performance verification using the transport aircraft simulation. The autopilot control laws were programmed in FORTRAN 4 in order to isolate the design process from requirements peculiar to an individual computer.

TRPV4 activation mediates flow-induced nitric oxide production in the rat thick ascending limb

PubMed Central

Garvin, Jeffrey L.

2014-01-01

Nitric oxide (NO) regulates renal function. Luminal flow stimulates NO production in the thick ascending limb (TAL). Transient receptor potential vanilloid 4 (TRPV4) is a mechano-sensitive channel activated by luminal flow in different types of cells. We hypothesized that TRPV4 mediates flow-induced NO production in the rat TAL. We measured NO production in isolated, perfused rat TALs using the fluorescent dye DAF FM. Increasing luminal flow from 0 to 20 nl/min stimulated NO from 8 ± 3 to 45 ± 12 arbitrary units (AU)/min (n = 5; P < 0.05). The TRPV4 antagonists, ruthenium red (15 μmol/l) and RN 1734 (10 μmol/l), blocked flow-induced NO production. Also, luminal flow did not increase NO production in the absence of extracellular calcium. We also studied the effect of luminal flow on NO production in TALs transduced with a TRPV4shRNA. In nontransduced TALs luminal flow increased NO production by 47 ± 17 AU/min (P < 0.05; n = 5). Similar to nontransduced TALs, luminal flow increased NO production by 39 ± 11 AU/min (P < 0.03; n = 5) in TALs transduced with a control negative sequence-shRNA while in TRPV4shRNA-transduced TALs, luminal flow did not increase NO production (Δ10 ± 15 AU/min; n = 5). We then tested the effect of two different TRPV4 agonists on NO production in the absence of luminal flow. 4α-Phorbol 12,13-didecanoate (1 μmol/l) enhanced NO production by 60 ± 11 AU/min (P < 0.002; n = 7) and GSK1016790A (10 ηmol/l) increased NO production by 52 ± 15 AU/min (P < 0.03; n = 5). GSK1016790A (10 ηmol/l) did not stimulate NO production in TRPV4shRNA-transduced TALs. We conclude that activation of TRPV4 channels mediates flow-induced NO production in the rat TAL. PMID:24966090

Thermal convection of liquid metal in the titanium reduction reactor

NASA Astrophysics Data System (ADS)

Teimurazov, A.; Frick, P.; Stefani, F.

2017-06-01

The structure of the convective flow of molten magnesium in a metallothermic titanium reduction reactor has been studied numerically in a three-dimensional non-stationary formulation with conjugated heat transfer between liquid magnesium and solids (steel walls of the cavity and titanium block). A nonuniform computational mesh with a total of 3.7 million grid points was used. The Large Eddy Simulation technique was applied to take into account the turbulence in the liquid phase. The instantaneous and average characteristics of the process and the velocity and temperature pulsation fields are analyzed. The simulations have been performed for three specific heating regimes: with furnace heaters operating at full power, with furnace heaters switched on at the bottom of the vessel only, and with switched-off furnace heaters. It is shown that the localization of the cooling zone can completely reorganize the structure of the large-scale flow. Therefore, by changing heating regimes, it is possible to influence the flow structure for the purpose of creating the most favorable conditions for the reaction. It is also shown that the presence of the titanium block strongly affects the flow structure.

Design and numeric evaluation of a novel axial-flow left ventricular assist device.

PubMed

Toptop, Koral; Kadipasaoglu, Kamuran A

2013-01-01

Virtual design characteristics and performance of the first Turkish axial-flow left ventricular assist device (LVAD) are presented, with emphasis on rotor geometry. The patented rotor design includes a central flow channel carved inside the main block, which carries permanent magnets. A concentric rotor-stator gap minimizes the distance between respective magnets, improving electromagnetic efficiency and creating a second blood pathway. Dual sets of three helical blades, placed on the shaft and external surface of the rotor block, ensure unidirectionality. Hemodynamic performance was tested with computational fluid dynamics (CFD); and rotor-blade geometry was optimized, to maximize overall efficiency d and minimize backflow and wall shear stresses. For a shaft radius of 4.5 mm, rotor blade height of 2.5 mm, and blade inlet and exit metal angles of 67° and 32°, pump operation at the nominal head-flow combination (5 L/min and 100.4 mm Hg) was achieved at a rotor speed of 10,313 rpm. At the nominal point, backflow as percent of total flow was 7.29 and 29.87% at rotor inlet and exit, respectively; overall hydraulic efficiency reached 21.59%; and maximum area-averaged shroud shear was 520 Pa. Overall efficiency peaked at 24.07% for a pump flow of 6.90 L/min, and averaged at 22.57% within the flow range of 4-8 L/min. We concluded that the design satisfies initial rotor design criteria, and that continued studies with diffuser optimization and transient flow analysis are warranted.

Advective and Conductive Heat Flow Budget Across the Wagner Basin, Northern Gulf of California

NASA Astrophysics Data System (ADS)

Neumann, F.; Negrete-Aranda, R.; Contreras, J.; Müller, C.; Hutnak, M.; Gonzalez-Fernandez, A.; Harris, R. N.; Sclater, J. G.

2015-12-01

In May 2015, we conducted a cruise across the northern Gulf of California, an area of continental rift basin formation and rapid deposition of sediments. The cruise was undertaken aboard the R/V Alpha Helix; our goal was to study variation in superficial conductive heat flow, lateral changes in the shallow thermal conductivity structure, and advective transport of heat across the Wagner basin. We used a Fielax heat flow probe with 22 thermistors that can penetrate up to 6 m into the sediment cover. The resulting data set includes 53 new heat flow measurements collected along three profiles. The longest profile (42 km) contains 30 measurements spaced 1-2 km apart. The western part of the Wagner basin (hanging wall block) exhibit low to normal conductive heat flow whereas the eastern part of the basin (foot wall block) heat flow is high to very high (up to 2500 mWm-2). Two other short profiles (12 km long each) focused on resolving an extremely high heat flow anomaly up to 15 Wm-2 located near the intersection between the Wagner bounding fault system and the Cerro Prieto fault. We hypothesize that the contrasting heat flow values observed across the Wagner basin are due to horizontal water circulation through sand layers and fault pathways of high permeability. Circulation appears to be from west (recharge zone) to east (discharge zone). Additionally, our results reveal strong vertical advection of heat due to dehydration reactions and compaction of fine grained sediments.

Simulant Gas Test Technique Feasibility

DTIC Science & Technology

1990-05-01

DY’NAMICS LABORATORY WRIGHT RESEARCH AND DEVELOPMENT CENTER AIR FORCE SYSTEMS COMMAND WRIGHT-PATTERSON AIR FORCE BASE, OHIO 45433-6553 NOTIr’ When...TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Hypersonic-test Air -chemistry Non-equilibrium-flow 0g...ABSTRACT (Continue on reverse if necessary and identify by block number) ’[lie Ulcertaillty engendered by non-equilibrium air effects on hypersonic

Inlet nozzle assembly

DOEpatents

Christiansen, David W.; Karnesky, Richard A.; Precechtel, Donald R.; Smith, Bob G.; Knight, Ronald C.

1987-01-01

An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

Inlet nozzle assembly

DOEpatents

Christiansen, D.W.; Karnesky, R.A.; Knight, R.C.; Precechtel, D.R.; Smith, B.G.

1985-09-09

An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

A decision-support tool for the control of urban noise pollution.

PubMed

Suriano, Marcia Thais; de Souza, Léa Cristina Lucas; da Silva, Antonio Nelson Rodrigues

2015-07-01

Improving the quality of life is increasingly seen as an important urban planning goal. In order to reach it, various tools are being developed to mitigate the negative impacts of human activities on society. This paper develops a methodology for quantifying the population's exposure to noise, by proposing a classification of urban blocks. Taking into account the vehicular flow and traffic composition of the surroundings of urban blocks, we generated a noise map by applying a computational simulation. The urban blocks were classified according to their noise range and then the population was estimated for each urban block, by a process which was based on the census tract and the constructed area of the blocks. The acoustical classes of urban blocks and the number of inhabitants per block were compared, so that the population exposed to noise levels above 65 dB(A) could be estimated, which is the highest limit established by legislation. As a result, we developed a map of the study area, so that urban blocks that should be priority targets for noise mitigation actions can be quickly identified.

Upscaling of Hydraulic Conductivity using the Double Constraint Method

NASA Astrophysics Data System (ADS)

El-Rawy, Mustafa; Zijl, Wouter; Batelaan, Okke

2013-04-01

The mathematics and modeling of flow through porous media is playing an increasingly important role for the groundwater supply, subsurface contaminant remediation and petroleum reservoir engineering. In hydrogeology hydraulic conductivity data are often collected at a scale that is smaller than the grid block dimensions of a groundwater model (e.g. MODFLOW). For instance, hydraulic conductivities determined from the field using slug and packer tests are measured in the order of centimeters to meters, whereas numerical groundwater models require conductivities representative of tens to hundreds of meters of grid cell length. Therefore, there is a need for upscaling to decrease the number of grid blocks in a groundwater flow model. Moreover, models with relatively few grid blocks are simpler to apply, especially when the model has to run many times, as is the case when it is used to assimilate time-dependent data. Since the 1960s different methods have been used to transform a detailed description of the spatial variability of hydraulic conductivity to a coarser description. In this work we will investigate a relatively simple, but instructive approach: the Double Constraint Method (DCM) to identify the coarse-scale conductivities to decrease the number of grid blocks. Its main advantages are robustness and easy implementation, enabling to base computations on any standard flow code with some post processing added. The inversion step of the double constraint method is based on a first forward run with all known fluxes on the boundary and in the wells, followed by a second forward run based on the heads measured on the phreatic surface (i.e. measured in shallow observation wells) and in deeper observation wells. Upscaling, in turn is inverse modeling (DCM) to determine conductivities in coarse-scale grid blocks from conductivities in fine-scale grid blocks. In such a way that the head and flux boundary conditions applied to the fine-scale model are also honored at the coarse-scale. Exemplification will be presented for the Kleine Nete catchment, Belgium. As a result we identified coarse-scale conductivities while decreasing the number of grid blocks with the advantage that a model run costs less computation time and requires less memory space. In addition, ranking of models was investigated.

Aircraft dual-shaft jet engine with indirect action fuel flow controller

NASA Astrophysics Data System (ADS)

Tudosie, Alexandru-Nicolae

2017-06-01

The paper deals with an aircraft single-jet engine's control system, based on a fuel flow controller. Considering the engine as controlled object and its thrust the most important operation effect, from the multitude of engine's parameters only its rotational speed n is measurable and proportional to its thrust, so engine's speed has become the most important controlled parameter. Engine's control system is based on fuel injection Qi dosage, while the output is engine's speed n. Based on embedded system's main parts' mathematical models, the author has described the system by its block diagram with transfer functions; furthermore, some Simulink-Matlab simulations are performed, concerning embedded system quality (its output parameters time behavior) and, meanwhile, some conclusions concerning engine's parameters mutual influences are revealed. Quantitative determinations are based on author's previous research results and contributions, as well as on existing models (taken from technical literature). The method can be extended for any multi-spool engine, single- or twin-jet.

Task-evoked BOLD responses are normal in areas of diaschisis after stroke.

PubMed

Fair, Damien A; Snyder, Abraham Z; Connor, Lisa Tabor; Nardos, Binyam; Corbetta, Maurizio

2009-01-01

Cerebral infarction can cause diaschisis, a reduction of blood flow and metabolism in areas of the cortex distant from the site of the lesion. Although the functional magnetic resonance imaging (fMRI) blood oxygen level dependent (BOLD) signal is increasingly used to examine the neural correlates of recovery in stroke, its reliability in areas of diaschisis is uncertain. The effect of chronic diaschisis as measured by resting positron emission tomography on task-evoked BOLD responses during word-stem completion in a block design fMRI study was examined in 3 patients, 6 months after a single left hemisphere stroke involving the inferior frontal gyrus and operculum. The BOLD responses were minimally affected in areas of chronic diaschisis. Within the confines of this study, the mechanism underlying the BOLD signal, which includes a mismatch between neuronally driven increases in blood flow and a corresponding increase in oxygen use, appears to be intact in areas of chronic diaschisis.

Out-of-plane heat transfer in van der Waals stacks through electron-hyperbolic phonon coupling

NASA Astrophysics Data System (ADS)

Tielrooij, Klaas-Jan; Hesp, Niels C. H.; Principi, Alessandro; Lundeberg, Mark B.; Pogna, Eva A. A.; Banszerus, Luca; Mics, Zoltán; Massicotte, Mathieu; Schmidt, Peter; Davydovskaya, Diana; Purdie, David G.; Goykhman, Ilya; Soavi, Giancarlo; Lombardo, Antonio; Watanabe, Kenji; Taniguchi, Takashi; Bonn, Mischa; Turchinovich, Dmitry; Stampfer, Christoph; Ferrari, Andrea C.; Cerullo, Giulio; Polini, Marco; Koppens, Frank H. L.

2018-01-01

Van der Waals heterostructures have emerged as promising building blocks that offer access to new physics, novel device functionalities and superior electrical and optoelectronic properties1-7. Applications such as thermal management, photodetection, light emission, data communication, high-speed electronics and light harvesting8-16 require a thorough understanding of (nanoscale) heat flow. Here, using time-resolved photocurrent measurements, we identify an efficient out-of-plane energy transfer channel, where charge carriers in graphene couple to hyperbolic phonon polaritons17-19 in the encapsulating layered material. This hyperbolic cooling is particularly efficient, giving picosecond cooling times for hexagonal BN, where the high-momentum hyperbolic phonon polaritons enable efficient near-field energy transfer. We study this heat transfer mechanism using distinct control knobs to vary carrier density and lattice temperature, and find excellent agreement with theory without any adjustable parameters. These insights may lead to the ability to control heat flow in van der Waals heterostructures.

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

Shum, Andrew D.; Parkinson, Dilworth Y.; Xiao, Xianghui

The performance of polymer-electrolyte fuel cells is heavily dependent on proper management of liquid water. One particular reason is that liquid water can collect in the gas diffusion layers (GDLs) blocking the reactant flow to the catalyst layer. This results in increased mass-transport losses. At higher temperatures, evaporation of water becomes a dominant water-removal mechanism and specifically phase-change-induced (PCI) flow is present due to thermal gradients. This study used synchrotron based micro X-ray computed tomography (CT) to visualize and quantify the water distribution within gas diffusion layers subject to a thermal gradient. Plotting saturation as a function of through-plane distancemore » quantitatively shows water redistribution, where water evaporates at hotter locations and condenses in colder locations. The morphology of the 2 GDLs on the micro-scale, as well as evaporating water clusters, are resolved, indicating that the GDL voids are slightly prolate, whereas water clusters are oblate. From the mean radii of water distributions and visual inspection, it is observed that larger water clusters evaporate faster than smaller ones.« less

Kinetic Effects on Self-Assembly and Function of Protein-Polymer Bioconjugates in Thin Films Prepared by Flow Coating.

PubMed

Chang, Dongsook; Huang, Aaron; Olsen, Bradley D

2017-01-01

The self-assembly of nanostructured globular protein arrays in thin films is demonstrated using protein-polymer block copolymers based on a model protein mCherry and the polymer poly(oligoethylene glycol acrylate) (POEGA). Conjugates are flow coated into thin films on a poly(ethylene oxide) grafted Si surface, forming self-assembled cylindrical nanostructures with POEGA domains selectively segregating to the air-film interface. Long-range order and preferential arrangement of parallel cylinders templated by selective surfaces are demonstrated by controlling relative humidity. Long-range order increases with coating speed when the film thicknesses are kept constant, due to reduced nucleation per unit area of drying film. Fluorescence emission spectra of mCherry in films prepared at <25% relative humidity shows a small shift suggesting that proteins are more perturbed at low humidity than high humidity or the solution state. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulations of pattern dynamics for reaction-diffusion systems via SIMULINK

PubMed Central

2014-01-01

Background Investigation of the nonlinear pattern dynamics of a reaction-diffusion system almost always requires numerical solution of the system’s set of defining differential equations. Traditionally, this would be done by selecting an appropriate differential equation solver from a library of such solvers, then writing computer codes (in a programming language such as C or Matlab) to access the selected solver and display the integrated results as a function of space and time. This “code-based” approach is flexible and powerful, but requires a certain level of programming sophistication. A modern alternative is to use a graphical programming interface such as Simulink to construct a data-flow diagram by assembling and linking appropriate code blocks drawn from a library. The result is a visual representation of the inter-relationships between the state variables whose output can be made completely equivalent to the code-based solution. Results As a tutorial introduction, we first demonstrate application of the Simulink data-flow technique to the classical van der Pol nonlinear oscillator, and compare Matlab and Simulink coding approaches to solving the van der Pol ordinary differential equations. We then show how to introduce space (in one and two dimensions) by solving numerically the partial differential equations for two different reaction-diffusion systems: the well-known Brusselator chemical reactor, and a continuum model for a two-dimensional sheet of human cortex whose neurons are linked by both chemical and electrical (diffusive) synapses. We compare the relative performances of the Matlab and Simulink implementations. Conclusions The pattern simulations by Simulink are in good agreement with theoretical predictions. Compared with traditional coding approaches, the Simulink block-diagram paradigm reduces the time and programming burden required to implement a solution for reaction-diffusion systems of equations. Construction of the block-diagram does not require high-level programming skills, and the graphical interface lends itself to easy modification and use by non-experts. PMID:24725437

Crustal anisotropy from Moho converted Ps wave splitting and geodynamic implications in Northeastern margin of Tibetan Plateau

NASA Astrophysics Data System (ADS)

Xie, Z.; Wu, Q.; Zhang, R.

2017-12-01

Collision between Indian and Eurasian result in intense deformation and crustal shortening in the Tibetan Plateau. NE margin of Tibetan Plateau experienced complex deformation between Qilian orogen and its adjacent blocks, Alxa Block in the north and Ordos Block in the east. We focus on if there any evidences exist in the NE margin of Tibetan Plateau, which can support crustal channel flow model. China Earthquake Administration had deployed temporary seismic array which is called ChinaArray Phase Ⅱ, dense seismic stations covered NE margin of Tibetan Plateau. Seismic data recorded by 81 seismic stations is applied in this research. We calculated receiver functions with time-domain deconvolution. We selected RFs which have clear Ps phase both in radial and transverse components to measure Ps splitting owing to crustal anisotropy, and 130 pairs of anisotropy parameters of 51 seismic stations were obtained. We would like to discuss about dynamic mechanism of this area using crustal anisotropy associated with the result of SKS-splitting and surface constrains like GPS velocity. The result can be summarized as follows. The large scale of delay time imply that the crustal anisotropy mainly derives from middle to lower crust rather than upper crust. In the southeastern part of the research area, crustal anisotropy is well agree with the result computed form SKS-splitting and GPS velocity directions trending NWW-SEE or E-W direction. This result imply a vertically coherent deformation in the area as the directions of crustal anisotropy trend to be perpendicular to the direction of normal stress. In the middle and north part of the research area, the fast polarization direction of crustal anisotropy is NEE-SWW or E-W direction, parallels with direction of GPS velocity, but differ to the direction of the result of SKS-splitting. This result may imply that decoupled deformation in this area associated with middle to lower crustal flow.

Simulations of pattern dynamics for reaction-diffusion systems via SIMULINK.

PubMed

Wang, Kaier; Steyn-Ross, Moira L; Steyn-Ross, D Alistair; Wilson, Marcus T; Sleigh, Jamie W; Shiraishi, Yoichi

2014-04-11

Investigation of the nonlinear pattern dynamics of a reaction-diffusion system almost always requires numerical solution of the system's set of defining differential equations. Traditionally, this would be done by selecting an appropriate differential equation solver from a library of such solvers, then writing computer codes (in a programming language such as C or Matlab) to access the selected solver and display the integrated results as a function of space and time. This "code-based" approach is flexible and powerful, but requires a certain level of programming sophistication. A modern alternative is to use a graphical programming interface such as Simulink to construct a data-flow diagram by assembling and linking appropriate code blocks drawn from a library. The result is a visual representation of the inter-relationships between the state variables whose output can be made completely equivalent to the code-based solution. As a tutorial introduction, we first demonstrate application of the Simulink data-flow technique to the classical van der Pol nonlinear oscillator, and compare Matlab and Simulink coding approaches to solving the van der Pol ordinary differential equations. We then show how to introduce space (in one and two dimensions) by solving numerically the partial differential equations for two different reaction-diffusion systems: the well-known Brusselator chemical reactor, and a continuum model for a two-dimensional sheet of human cortex whose neurons are linked by both chemical and electrical (diffusive) synapses. We compare the relative performances of the Matlab and Simulink implementations. The pattern simulations by Simulink are in good agreement with theoretical predictions. Compared with traditional coding approaches, the Simulink block-diagram paradigm reduces the time and programming burden required to implement a solution for reaction-diffusion systems of equations. Construction of the block-diagram does not require high-level programming skills, and the graphical interface lends itself to easy modification and use by non-experts.

Highχ block copolymers for directed self-assembly patterning without the need for topcoat or solvent annealing

NASA Astrophysics Data System (ADS)

Xu, Kui; Hockey, Mary Ann; Calderas, Eric; Guerrero, Douglas; Sweat, Daniel; Fiehler, Jeffrey

2017-03-01

High-χ block copolymers for directed self-assembly (DSA) patterning that do not need topcoat or solvent annealing have been developed. A variety of functionalities have been successfully added into the block copolymers, such as balanced surface energy between the polymer blocks, outstandingly high χ, tunable glass transition temperature (Tg), and selective crosslinking. Perpendicular orientation control, as desired for patterning, of the block copolymers can be simply achieved by thermal annealing due to the equal surface energy of the polymer blocks at the annealing temperatures, which allows avoiding solvent annealing or top-coat. The χ value can be tuned up to achieve L0 as low as 8-10 nm for lamellar-structured block copolymers and hole/pillar size as small as 5-6 nm for cylinder-structured block copolymers. The Tg of the block copolymers can be tuned to improve the kinetics of thermal annealing by enhancing the polymer chain mobility. Block-selective crosslinking facilitates the pattern transfer by mitigating pattern collapse during wet etching and improving oxygen plasma etching selectivity between the polymer blocks. This paper provides an introductory review of our high-χ block copolymer materials with various functionalities for achieving improved DSA performance.

Classical conformal blocks and accessory parameters from isomonodromic deformations

NASA Astrophysics Data System (ADS)

Lencsés, Máté; Novaes, Fábio

2018-04-01

Classical conformal blocks appear in the large central charge limit of 2D Virasoro conformal blocks. In the AdS3 /CFT2 correspondence, they are related to classical bulk actions and used to calculate entanglement entropy and geodesic lengths. In this work, we discuss the identification of classical conformal blocks and the Painlevé VI action showing how isomonodromic deformations naturally appear in this context. We recover the accessory parameter expansion of Heun's equation from the isomonodromic τ -function. We also discuss how the c = 1 expansion of the τ -function leads to a novel approach to calculate the 4-point classical conformal block.

Inhibition of Breast Cancer-Induced Angiogenesis by a Diverged Homeobox Gene

DTIC Science & Technology

2006-05-01

and then harvested for flow cytometry using appropriate antibodies. Ad.Gax blocked the expression of VCAM-1, E-selectin, and ICAM-1. DOD Idea Award...solution. Bands were visualized by chemiluminescence using the ECL-Plus reagent (Amersham, Piscataway, NJ). Flow Cytometry Cells were harvested after...33), all of whose down-regulation we have confirmed using real time quantitative RT-PCR, Western blot, and flow cytometry (Fig. 5). Moreover, Gax

Trial-dependent psychometric functions accounting for perceptual learning in 2-AFC discrimination tasks.

PubMed

Kattner, Florian; Cochrane, Aaron; Green, C Shawn

2017-09-01

The majority of theoretical models of learning consider learning to be a continuous function of experience. However, most perceptual learning studies use thresholds estimated by fitting psychometric functions to independent blocks, sometimes then fitting a parametric function to these block-wise estimated thresholds. Critically, such approaches tend to violate the basic principle that learning is continuous through time (e.g., by aggregating trials into large "blocks" for analysis that each assume stationarity, then fitting learning functions to these aggregated blocks). To address this discrepancy between base theory and analysis practice, here we instead propose fitting a parametric function to thresholds from each individual trial. In particular, we implemented a dynamic psychometric function whose parameters were allowed to change continuously with each trial, thus parameterizing nonstationarity. We fit the resulting continuous time parametric model to data from two different perceptual learning tasks. In nearly every case, the quality of the fits derived from the continuous time parametric model outperformed the fits derived from a nonparametric approach wherein separate psychometric functions were fit to blocks of trials. Because such a continuous trial-dependent model of perceptual learning also offers a number of additional advantages (e.g., the ability to extrapolate beyond the observed data; the ability to estimate performance on individual critical trials), we suggest that this technique would be a useful addition to each psychophysicist's analysis toolkit.

Groundwater flow cycling between a submarine spring and an inland fresh water spring.

PubMed

Davis, J Hal; Verdi, Richard

2014-01-01

Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

The prokaryotic thermophilic TF1-ATPase is functionally compatible with the eukaryotic CFo-part of the chloroplast ATP-synthase.

PubMed

Galmiche, J M; Pezennec, S; Zhao, R; Girault, G; Baeuerlein, E

1994-01-31

The ATP synthase from chloroplasts, CFo.F1, was reconstituted into liposomes, from which most of CF1 was removed by a short treatment with guanidinium chloride. ATP-dependent proton uptake was restored with these CFo-liposomes even better by the addition of the bacterial TF1-than of the related CF1-part. This proton uptake was prevented by tentoxin, a specific inhibitor of the CF1-ATPase, in these CFo.F1-liposomes, but not in the hybrid CFo.TF1-liposomes. Venturicidin, a specific inhibitor of proton flow through CFo, was able to block it in both the hybrid CFo.TF1-liposomes and reconstituted CFo.F1-liposomes. These results indicate that the bacterial TF1-part binds to the eukaryotic CFo-part of four subunits forming a functional CFo.TF1-ATPase.

Shape fluctuations of nearly spherical lipid vesicles and emulsion droplets.

PubMed

Bivas, Isak

2010-06-01

It is known that the relaxation of the shape fluctuations of nearly spherical lipid vesicles is accompanied by a lateral displacement of the monolayers, comprising their bilayers. In this work a dissipation mechanism of the mechanical energy stored in the fluctuation is revealed that concerns the viscous friction of the flow in the liquid around the vesicle caused by this displacement. The time correlation functions of each of the vesicle's fluctuation modes are calculated as a function of the mechanical and rheological properties of the system which are the tension of the vesicle bilayer, its bending elasticities at free and blocked flip-flop, the viscosities of the liquids bathing the bilayer, the friction coefficient between the two monolayers, as well as the vesicle's dimensions: its bilayer thickness and radius. The correlations of the shape fluctuations of nearly spherical emulsion droplets are also calculated for different viscosities of the liquid inside and outside the droplet.

Characterizing a complex aquifer system using geophysics, hydrodynamics and geochemistry: A new distribution of Miocene aquifers in the Zéramdine and Mahdia-Jébéniana blocks (east-central Tunisia)

NASA Astrophysics Data System (ADS)

Lachaal, Fethi; Bédir, Mourad; Tarhouni, Jamila; Gacha, Ayadi Ben; Leduc, Christian

2011-06-01

The Zéramdine and Mahdia-Jébéniana blocks are located in the Sahel region in east-central Tunisia. Active tectonics have divided the region into numerous sub-units, as result of multiple phases of distension and compression. The Miocene fluvio-deltaic sediment sandy layers have aquiferous capacities but their hydraulic properties are still unknown, due to the lack of investigation wells. This study proposes a new description of the regional hydrogeology of Miocene deposits. Seismic-reflection and wireline logging of petroleum and water wells were used to understand the structure and the geometry of the Miocene reservoirs. The groundwater flow and its relationship to the sedimentary and tectonic context were then identified by studying piezometry and hydrochemistry. Two Miocene deep aquifer systems were identified: (1) Zéramdine-Béni Hassen to the north and (2) Jébéniana-Ksour Essef to the south. These aquifers are separated by the Mahdia graben. Other major tectonic structures, such as the Zéramdine fault corridor, the Moknine graben, and the El-Jem half-graben represent lateral boundaries for these aquifers. Other deeper sandy and clayey-sandy reservoirs were also identified in the area. Their repartition, thickness and depth vary from one block to other. Hydrodynamics of the deep aquifers seems to be controlled by geological structures. Two independent compartments were identified: in the northern block groundwater flows from West to East and from Northwest to Southeast, while in the southern block it flows from Northwest to Southeast. Geochemical facies are of two types: Na-Ca-Cl-SO 4 for the Zéramdine-Béni Hassen deep aquifer and Na-Cl for the Jébéniana-Ksour Essef deep aquifer. The hydrodynamic and geochemical results confirm the sharing of the Miocene sediments into two aquifers.

Blood flow of the right and left submandibular gland during unilateral carotid artery occlusion in rat: role of nitric oxide.

PubMed

Vág, J; Hably, C; Fazekas, A; Bartha, J

1999-01-01

The aim of the present study was to investigate the effect of unilateral carotid artery occlusion on the blood flow of submandibular gland in anesthetized rats and identify the role of nitric oxide (NO) in blood flow changes after the artery occlusion. L-NAME (N omega-nitro-L-arginine-methyl-ester; 10 mg/kg/day, per os) dissolved in tap water was used to block nitric oxide synthase. Glandular blood flow was measured using Sapirstein's indicator (86Rb) distribution technique. In the control animals the blood flow of left (ligated side) submandibular gland was lower than in the right (unligated side) one (right: 76.4+/-15.4 ml/min/100 g, 64.1+/-13.4 ml/min/100 g, p<0.01). The blood flow of submandibular glands decreased in NOS blocked group versus control. The vascular resistance after L-NAME treatment was elevated (control: 11+/-2.3 R/kg, L-NAME: 17.5+/-4.1 R/kg, p<0.001). In L-NAME group the difference between blood flow value of the left and right submandibular gland was significantly lower than in the control group (control: -16%, NAME: -8%, p<0.01). The maintenance of the blood flow in the left submandibular gland during ligation of the left common carotid artery could be due to the good vascular anastomotic system at these regions and adaptation of the submandibular vessels to the decreased perfusion pressure. Nitric oxide may have a role in the regulation of blood flow tinder this condition.

Impact of chemical peeling combined with negative pressure on human skin.

PubMed

Kim, S J; Kang, I J; Shin, M K; Jeong, K H; Baek, J H; Koh, J S; Lee, S J

2016-10-01

In vivo changes in skin barrier function after chemical peeling with alpha hydroxyacids (AHAs) have been previously reported. However, the additional effects of physical treatment with chemical agents on skin barrier function have not been adequately studied. This study measured the degree of acute skin damage and the time required for skin barrier repair using non-invasive bioengineering methods in vivo with human skin to investigate the additional effect of a 4% AHA chemical jet accelerated at supersonic velocities. Thirteen female subjects (average age: 29.54 ± 4.86 years) participated in this study. The faces of the subjects were divided into half according to the block randomization design and were then assigned to receive AHA peeling alone or AHA peeling combined with pneumatic pressure on each side of the face. Transepidermal water loss (TEWL), skin colour and skin blood flow were evaluated at baseline and at 30 min, 2, 5 and 7 days after treatment. The TEWL and skin blood flow were significantly increased after 30 min in chemodermabrasion compared with chemical peeling alone (P < 0.05). The TEWL and skin blood flow recovered to baseline after 2 days, and TEWL was significantly decreased at 7 days compared with chemical peeling alone (P < 0.05). Chemodermabrasion can temporarily impair skin barriers, but it is estimated that it can enhance the skin barrier function after 7 days compared to the use of a chemical agent alone. In addition, chemodermabrasion has a more effective impact in the dermis and relatively preserves the skin barrier. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

The influence of diltiazem and nifedipine on renal function in the rat.

PubMed Central

Johns, E. J.

1985-01-01

The effect of intravenous administration of the calcium-entry blocking drugs, diltiazem and nifedipine, on renal haemodynamic and tubular function was examined in denervated kidneys of pentobarbitone-anaesthetized rats. Infusion of vehicle for the compounds had no effect on renal function which was stable for the duration of the experiments. Diltiazem was infused at 5, 10 and 20 micrograms kg-1 min-1. Blood pressure did not change following 5 micrograms kg-1 min-1 diltiazem but was significantly reduced, by 12 mmHg, after 10 micrograms kg-1 min-1 and by 17 mmHg after 20 micrograms kg-1 min-1. Renal blood flow was not affected by any dose of diltiazem while at the lowest dose of drug, glomerular filtration rate (g.f.r.) was significantly increased, by 24%. Absolute and fractional sodium excretion were increased significantly, 154% and 77% respectively, by 5 micrograms kg-1 min-1 diltiazem, 20% and 24% respectively, by 10 micrograms kg-1 min-1 diltiazem, but were unchanged by 20 micrograms kg-1 min-1. Infusion of nifedipine at 0.5, 1.0 and 2.0 micrograms kg-1 min-1 decreased systemic blood pressure by 9, 9 and 20 mmHg, respectively. Renal blood flow was increased (7%) by 1.0 microgram kg-1 min-1 only, while g.f.r. did not change at any dose. Urine flow, absolute and fractional sodium excretions were increased, 127%, 96% and 90% respectively, by 0.5 microgram kg-1 min-1 nifedipine, 127%, 197% and 194% respectively, by 1.0 microgram kg-1 min-1, while these variables remained unchanged by a dose of 2.0 micrograms kg-1 min-1.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3986432

Brain functional connectivity during the experience of thought blocks in schizophrenic patients with persistent auditory verbal hallucinations: an EEG study.

PubMed

Angelopoulos, Elias; Koutsoukos, Elias; Maillis, Antonis; Papadimitriou, George N; Stefanis, Costas

2014-03-01

Thought blocks (TBs) are characterized by regular interruptions in the stream of thought. Outward signs are abrupt and repeated interruptions in the flow of conversation or actions while subjective experience is that of a total and uncontrollable emptying of the mind. In the very limited bibliography regarding TB, the phenomenon is thought to be conceptualized as a disturbance of consciousness that can be attributed to stoppages of continuous information processing due to an increase in the volume of information to be processed. In an attempt to investigate potential expression of the phenomenon on the functional properties of electroencephalographic (EEG) activity, an EEG study was contacted in schizophrenic patients with persisting auditory verbal hallucinations (AVHs) who additionally exhibited TBs. In this case, we hypothesized that the persistent and dense AVHs could serve the role of an increased information flow that the brain is unable to process, a condition that is perceived by the person as TB. Phase synchronization analyses performed on EEG segments during the experience of TBs showed that synchrony values exhibited a long-range common mode of coupling (grouped behavior) among the left temporal area and the remaining central and frontal brain areas. These common synchrony-fluctuation schemes were observed for 0.5 to 2s and were detected in a 4-s window following the estimated initiation of the phenomenon. The observation was frequency specific and detected in the broad alpha band region (6-12Hz). The introduction of synchrony entropy (SE) analysis applied on the cumulative synchrony distribution showed that TB states were characterized by an explicit preference of the system to be functioned at low values of synchrony, while the synchrony values are broadly distributed during the recovery state. Our results indicate that during TB states, the phase locking of several brain areas were converged uniformly in a narrow band of low synchrony values and in a distinct time window, impeding thus the ability of the system to recruit and to process information during this time window. Copyright © 2014 Elsevier B.V. All rights reserved.

Geomorphology of the Arteara Holocene rock-avalanche deposit, Gran Canaria Island

NASA Astrophysics Data System (ADS)

Yepes, Jorge; Lomoschitz, Alejandro

2010-05-01

Abundant slide deposits cover the southern ravines of Grand Canary. These are mainly volcanic debris avalanches consisting of rock slides and debris slides. The main course of the Fataga ravine is entrenched 600m into the Phonolite Formation. At Arteara an accumulation of large reddish blocks has been characterised covering the right side of the ravine. The deposit has a surface area of 0.565 km2 and has been dated as a Holocene rock avalanche, because of its good state of conservation. The blocks cover a previous relief formed by a rock slide with a surface area of 1.236km2 and thought to be Pleistocene. The whole of the deposit is covered at its head by an active scree sequence. The rock slide deposit varies in thickness from 25m to 100m and has head and foot zones. The flanks are indicated by tributary streams with an arching course and anomalous confluence with the main ravine. Several fragmented rocky wedges can be seen at the head with local tilting against the slope. In addition, an elongated depression has formed coinciding with the fracture through the rocky wedges. This depression is partially masked by the rock avalanche deposits. The slide scar is hidden behind the rocky wedges, coinciding with the col between the Morro Garito and the erosion surface defined at the top of the Phonolite Formation. The foot of the rocky slide is affected by an incipient drainage network at present masked by the rock avalanche. These palaeochannels show the presence of several reactivation episodes that would have broken up the foot of the rock slide into several bodies. There is a mass of broken rock on the northern flank, presumably caused by a rock slide movement. There is a mass of disorganised rock in the central sector of the foot, probably caused by a debris slide-slump movement, as suggested by an elongated depression, the deformation of the layers and a reappearance of the deposit in the distal zone. This second gravitational deposit collided with the opposite side, where some remains can still be recognised. This was later covered by a layer of ordered rubble from the left bank. Blockage of the main course gave rise to an alluvial-torrential plain of boulders and gravels along the section upstream from Arteara. A network of braided channels has developed on this plain. At present, the advance of the rising erosion has cut through the slope deposit and is dismantling the alluvial-torrential plain. The rock avalanche defines an elongated tongue in the direction of flow, of varying thickness (1-15m) and L/H = 2.47 (displacement/total fall=1325m/535m), reappearing at the foot (Hr=15m). In general, the rock avalanche is adapted to the previous slide, although it has small overspill lobes on the lateral flanks. The low angle of friction deduced (=21.47°) agrees with the high mobility estimated from the L/H ratio and is due to the existence of a previous relief defined by the rock slide and the lubrication provided by the ignimbrite. This easily weathered material must have made up the gravel layer over which the lava blocks moved. The rock avalanche deposit varies widely in size and is structured in bands of loose blocks with a bimodal distribution (0.1-3m3; 10.30m3) and low selection. The blocks lie on a layer of loose, flat, angular gravels. The blocks are angular and show numerous signs of impact, including split and fragmented blocks, faces with conchoidal fractures, chipped edges and broken corners. The movement of the rock avalanche would have been a swift, dry granular flow. The avalanche would have had a leap component at the head, turbulent flow in the intermediate corridor and laminar flow in the distal zone. The leap component is identified by the accumulation of blocks in crests transversal to the flow and the presence of megablocks aligned with the flow. The turbulent component is identified by the chaotic accumulation of blocks in the palaeochannels and overspill lobes covering the flanks. The laminar component is identified by the bimodal distribution of blocks as concentric propagation waves. The available data are not sufficient to suggest a link between the rock avalanche and freeze-melt processes. However, evidence from several humid-subtropical episodes in the Quaternary suggests undermining of the scarp and triggering of the previous rock slide. The subsequent variation in the state of tensions on the shelf and the penetrating nature of the thermal retraction diaclases would justify the detachment of an approximately 2.82*106m3 block.

Block algebra in two-component BKP and D type Drinfeld-Sokolov hierarchies

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

Li, Chuanzhong, E-mail: lichuanzhong@nbu.edu.cn; He, Jingsong, E-mail: hejingsong@nbu.edu.cn

We construct generalized additional symmetries of a two-component BKP hierarchy defined by two pseudo-differential Lax operators. These additional symmetry flows form a Block type algebra with some modified (or additional) terms because of a B type reduction condition of this integrable hierarchy. Further we show that the D type Drinfeld-Sokolov hierarchy, which is a reduction of the two-component BKP hierarchy, possess a complete Block type additional symmetry algebra. That D type Drinfeld-Sokolov hierarchy has a similar algebraic structure as the bigraded Toda hierarchy which is a differential-discrete integrable system.

Quantitative measurement of channel-block hydraulic interactions by experimental saturation of a large, natural, fissured rock mass.

PubMed

Guglielmi, Y; Mudry, J

2001-01-01

The hydrodynamic behavior of fissured media relies on the relationships between a few very conductive fractures (channels) and the remaining low-conductivity fractures and matrix (blocks). We made a quantitative measurement of those relationships and their effect on water drainage and storage in a 19,000 m3 natural reservoir consisting of karstified limestones. This reservoir was artificially saturated with water by closing a water gate on the main outlet during a varying time (delta t) fixed by the operator. The water gate was completely or partly closed until the water pressure reached a particular specified value. If the water gate was left completely closed long enough, the water pressure was fixed by the elevation of temporary outlets at the site boundaries. The water elevation within the reservoir was monitored by means of pressure cells located on single fractures representative of the bedding plane and the two families of fractures of the massif network. The comparison of pressure variations with the network geometry allows us to identify a typical double permeability characterized by a few very conductive channels along 10 vertical faults. These channels limit blocks consisting of low-conductivity bedding planes and a rather impervious matrix. Depending on the closure interval, delta t, of the water gate, the total volume of water stored in the reservoir can vary from 0.8 m3 (delta t = 5 minutes) to 18.6 m3 (delta t = 2 days). Such a variance of storage versus closure time is explained by the reservoir's double permeability that is characterized by blocks that saturate much more slowly than channels. If plotted versus time, this injected volume fits a power relationship, according to the saturation state of the blocks. In less than 34 minutes, storage is close to zero in the blocks and to 1.6 to 2 m3 in the channels. For closing times shorter than 1 hour, only 1% of the volume that flows in the channels is stored into the blocks. Depending on the water pressure and for a given delta t = 3000 minutes, the volume of water stored is controlled by the geometry of the joint network and of the aquifer boundaries. Such an experiment shows that the flow is concentrated in about 10% of the fractured network (channels). The water storage that takes place in the 90% remaining fractures (blocks) depends mainly on time during which pressure remains high into the 10% channels. The accurate modeling of such typical double-permeability media needs a careful study of the geometry of the channels whose narrowings modify the flow and induce dam effects that maintain a high pressure gradient with surrounding blocks.

Acute increases in intraluminal pressure improve vasodilator responses in aged soleus muscle feed arteries.

PubMed

Seawright, John W; Luttrell, Meredith J; Woodman, Christopher R

2014-10-01

We tested the hypothesis that exposure to an acute increase in intraluminal pressure, to mimic pressure associated with a bout of exercise, improves nitric oxide (NO)-mediated endothelium-dependent dilation in aged soleus muscle feed arteries (SFA) and that improved endothelial function would persist after a 2 h recovery period. SFA from young (4-month) and old (24-month) Fischer 344 rats were cannulated and pressurized at 90 (P90) or 130 (P130) cmH2O for 60 min. At the end of the treatment period, pressure in the P130 SFA was lowered to 90 cmH2O for examination of endothelium-dependent [flow or acetylcholine (ACh)] and endothelium-independent [sodium nitroprusside (SNP)] vasodilation. To determine the role of NO, vasodilator responses were assessed in the presence of N (ω)-nitro-L-arginine (L-NNA). To determine whether the effects of pressure persisted following a recovery period at normal pressure, SFA were pressurized to 130 cmH2O for 60 min and subsequently lowered to 90 cmH2O for 2 h before assessing function. ACh- and flow-induced dilations were impaired in old SFA. Treatment with increased pressure for 60 min improved ACh- and flow-induced dilations in old SFA. SNP-induced dilation was improved in old and young SFA. The beneficial effect of pressure treatment on ACh- and flow-induced dilation in old SFA was blocked by L-NNA and was not present following a 2 h recovery period. These results indicate that an acute increase in intraluminal pressure improves NO-mediated endothelium-dependent dilation in aged SFA; however, the beneficial effect does not persist after 2 h.

TIGGERC: Turbomachinery Interactive Grid Generator for 2-D Grid Applications and Users Guide

NASA Technical Reports Server (NTRS)

Miller, David P.

1994-01-01

A two-dimensional multi-block grid generator has been developed for a new design and analysis system for studying multiple blade-row turbomachinery problems. TIGGERC is a mouse driven, interactive grid generation program which can be used to modify boundary coordinates and grid packing and generates surface grids using a hyperbolic tangent or algebraic distribution of grid points on the block boundaries. The interior points of each block grid are distributed using a transfinite interpolation approach. TIGGERC can generate a blocked axisymmetric H-grid, C-grid, I-grid or O-grid for studying turbomachinery flow problems. TIGGERC was developed for operation on Silicon Graphics workstations. Detailed discussion of the grid generation methodology, menu options, operational features and sample grid geometries are presented.

A Block Iterative Finite Element Model for Nonlinear Leaky Aquifer Systems

NASA Astrophysics Data System (ADS)

Gambolati, Giuseppe; Teatini, Pietro

1996-01-01

A new quasi three-dimensional finite element model of groundwater flow is developed for highly compressible multiaquifer systems where aquitard permeability and elastic storage are dependent on hydraulic drawdown. The model is solved by a block iterative strategy, which is naturally suggested by the geological structure of the porous medium and can be shown to be mathematically equivalent to a block Gauss-Seidel procedure. As such it can be generalized into a block overrelaxation procedure and greatly accelerated by the use of the optimum overrelaxation factor. Results for both linear and nonlinear multiaquifer systems emphasize the excellent computational performance of the model and indicate that convergence in leaky systems can be improved up to as much as one order of magnitude.

Alpha-1 antitrypsin blood test

MedlinePlus

... the lungs ( bronchiectasis ) Scarring of the liver ( cirrhosis ) Chronic obstructive pulmonary disease (COPD) Liver tumors Yellowing of the skin and eyes due to blocked bile flow ( obstructive ...

Influence of Mountains on Arctic Tropospheric Ozone

NASA Astrophysics Data System (ADS)

Whiteway, J. A.; Seabrook, J.

2015-12-01

Tropospheric ozone was measured above Ellesmere Island in the Canadian Arctic during spring using a differential absorption lidar (DIAL). Analysis of the observations revealed that mountains had a significant effect on the vertical distribution of ozone. Ozone depletion events were observed when air that had spent significant time near to the frozen surface of the Arctic Ocean reached Eureka. This air arrived at Eureka by flowing over the surrounding mountains. Surface level ozone depletion events were not observed during periods when mountains blocked the flow of air from over the sea ice. In the case of blocking there was an enhancement in the amount of ozone near the surface as air from the mid troposphere descended in the lee of the mountains. Three case studies will be presented.

Flow solution on a dual-block grid around an airplane

NASA Technical Reports Server (NTRS)

Eriksson, Lars-Erik

1987-01-01

The compressible flow around a complex fighter-aircraft configuration (fuselage, cranked delta wing, canard, and inlet) is simulated numerically using a novel grid scheme and a finite-volume Euler solver. The patched dual-block grid is generated by an algebraic procedure based on transfinite interpolation, and the explicit Runge-Kutta time-stepping Euler solver is implemented with a high degree of vectorization on a Cyber 205 processor. Results are presented in extensive graphs and diagrams and characterized in detail. The concentration of grid points near the wing apex in the present scheme is shown to facilitate capture of the vortex generated by the leading edge at high angles of attack and modeling of its interaction with the canard wake.

Barriers to front propagation in laminar, three-dimensional fluid flows

NASA Astrophysics Data System (ADS)

Doan, Minh; Simons, J. J.; Lilienthal, Katherine; Solomon, Tom; Mitchell, Kevin A.

2018-03-01

We present experiments on one-way barriers that block reaction fronts in a fully three-dimensional (3D) fluid flow. Fluorescent Belousov-Zhabotinsky reaction fronts are imaged with laser-scanning in a laminar, overlapping vortex flow. The barriers are analyzed with a 3D extension to burning invariant manifold (BIM) theory that was previously applied to two-dimensional advection-reaction-diffusion processes. We discover tube and sheet barriers that guide the front evolution. The experimentally determined barriers are explained by BIMs calculated from a model of the flow.

Effects of an Isolated Complete Right Bundle Branch Block on Mechanical Ventricular Function.

PubMed

Zhang, Qin; Xue, Minghua; Li, Zhan; Wang, Haiyan; Zhu, Lei; Liu, Xinling; Meng, Haiyan; Hou, Yinglong

2015-12-01

The purpose of this study was to investigate the effects of an isolated complete right bundle branch block on mechanical ventricular function. Two groups of participants were enrolled in this study: a block group, consisting of 98 patients with isolated complete right bundle branch blocks without structural heart disease, and a control group, consisting of 92 healthy adults. The diameter, end-diastolic area, end-systolic area, and right ventricular (RV) fractional area change were obtained to evaluate morphologic and systolic function by 2-dimensional sonographic technology. Systolic and diastolic velocities and time interval parameters were measured to assess mechanical ventricular performance using pulsed wave tissue Doppler imaging. Although there was no significant difference in the RV fractional area change between the patients with blocks and controls, the diameter, end-diastolic area, and end-systolic area of the RV were significantly larger in the patients with blocks (P < .05). In the patients with blocks, the peak velocities during systole and early diastole and the ratio of the peak velocities during early and late diastole decreased. The block group had a prolonged pre-ejection period, electromechanical delay time, and isovolumic relaxation time, a decreased ejection time, and an increased pre-ejection period/ejection time ratio, and the myocardial performance index (Tei index) at the basal RV lateral wall was significantly increased. There were no significant differences in any echocardiographic parameters at different sites of the left ventricle. In patients with isolated complete right bundle branch blocks, systolic and diastolic functions are impaired in the RV, and follow-up is needed. © 2015 by the American Institute of Ultrasound in Medicine.

Simulation Engine for Fluid Solid Interaction Problems and its Application to the Modelling of Air Blast Hazards in Block Cave Mining.

NASA Astrophysics Data System (ADS)

Galindo Torres, S. A.; Scheuermann, A.; Ruest, M.

2016-12-01

Air blasts that may occur in a block caving mining operation represent a significant hazard for personnel as well as to mining infrastructure. Uncontrolled caving of a large volume of broken rock into a mine void causes compression of the air within, forcing it to flow at high velocities into connecting tunnels such as extraction points beneath the cave or observation points intersecting the cave. This high velocity flow of air can cause injury to personnel and significant damage to equipment. In this presentation, we introduce a simulation engine for the air blast problem. The solid material is modelled using the Discrete Element Method (DEM) and the fluid (air) is modelled using the Lattice Boltzmann Method (LBM). The combined DEM-LBM approach has been introduced by our group at the University of Queensland[1]. LBM allows us to introduce an appropriate equation of state for the air that simulates compressibility as a function of the speed of sound. Validation examples are presented to justify the use of this tool for an air blasting situation. A section view of one simulation is provided in Fig 1. An investigation into the risk of developing air pockets as a function of fragment size distribution is also conducted and described. The fragment size distribution can be assessed during mining and the risk of air pockets forming (and consequently of air blast occurring) can be deduced and mitigation measures put in place. The effect of other key variables that can be determined from geotechnical investigations, such as fracture frequency, are also systematically explored. It is expected that the results of this study can elucidate key features of the air blasting phenomenon in order to formulate safer mining protocols. references 1. Galindo-Torres, S.A., A coupled Discrete Element Lattice Boltzmann Method for the simulation of fluid-solid interaction with particles of general shapes. Computer Methods in Applied Mechanics and Engineering, 2013. 265(0): p. 107-119.

Thinned crustal structure and tectonic boundary of the Nansha Block, southern South China Sea

NASA Astrophysics Data System (ADS)

Dong, Miao; Wu, Shi-Guo; Zhang, Jian

2016-12-01

The southern South China Sea margin consists of the thinned crustal Nansha Block and a compressional collision zone. The Nansha Block's deep structure and tectonic evolution contains critical information about the South China Sea's rifting. Multiple geophysical data sets, including regional magnetic, gravity and reflection seismic data, reveal the deep structure and rifting processes. Curie point depth (CPD), estimated from magnetic anomalies using a windowed wavenumber-domain algorithm, enables us to image thermal structures. To derive a 3D Moho topography and crustal thickness model, we apply Oldenburg algorithm to the gravity anomaly, which was extracted from the observed free air gravity anomaly data after removing the gravity effect of density variations of sediments, and temperature and pressure variations of the lithospheric mantle. We found that the Moho depth (20 km) is shallower than the CPD (24 km) in the Northwest Borneo Trough, possibly caused by thinned crust, low heat flow and a low vertical geothermal gradient. The Nansha Block's northern boundary is a narrow continent-ocean transition zone constrained by magnetic anomalies, reflection seismic data, gravity anomalies and an interpretation of Moho depth (about 13 km). The block extends southward beneath a gravity-driven deformed sediment wedge caused by uplift on land after a collision, with a contribution from deep crustal flow. Its southwestern boundary is close to the Lupar Line defined by a significant negative reduction to the pole (RTP) of magnetic anomaly and short-length-scale variation in crustal thickness, increasing from 18 to 26 km.

A bank-operated traveling-block cableway for stream discharge and sediment measurements

Treesearch

James J. Paradiso

2000-01-01

Streams often present a challenge for collecting flow and sediment measurements on a year-round basis. Streams that can normally be waded become hazardous during seasonal flows, either endangering hydrographers or precluding data collection completely. A hand-operated cableway permits the accurate and safe collection of discharge and sediment data from the stream bank...

33 CFR 154.2022 - Certification, recertification, or operational review-certifying entity responsibilities, generally.

Code of Federal Regulations, 2014 CFR

2014-07-01

... alarm and shutdown shown on the piping and instrumentation diagrams (P&IDs) and reviewed in the hazard... cleaning facility; and that (5) The automatic liquid block valve successfully stops flow of liquid to the... automatically stop the cargo flow to each transfer hose simultaneously, in the event an upset condition occurs...

Report on: Connecticut River Streambank Erosion Study, Massachusetts, New Hampshire and Vermont

DTIC Science & Technology

1979-11-01

Plastic filter cloths are used with considerable success beneath tiprap and other revetment materials such as articulated concrete blocks . The...rihutior unlimited II. SUPPLEMENTARY NOTES It. KEY WORDS (Continue on fever&e elde ifneceeeery and identify by block number). alluvial channel...erosion boat waves shear stress rock riprap lower bank erosion revetments flow control vegetation 20. ABSTRACT (Continue on reverse aide if neceesary and

Reducing leakage current in semiconductor devices

DOEpatents

Lu, Bin; Matioli, Elison de Nazareth; Palacios, Tomas Apostol

2018-03-06

A semiconductor device includes a first region having a first semiconductor material and a second region having a second semiconductor material. The second region is formed over the first region. The semiconductor device also includes a current blocking structure formed in the first region between first and second terminals of the semiconductor device. The current blocking structure is configured to reduce current flow in the first region between the first and second terminals.

A Comparative Study of the Electrical Structure of Circum Tibetan Plateau Orogenic Belts and its Tectonic Implications

NASA Astrophysics Data System (ADS)

Jin, Sheng; Zhang, Letian; Wei, Wenbo; Ye, Gaofeng; Jing, Jianen; Dong, Hao; Xie, Chengliang; Yin, Yaotian

2017-04-01

The Tibetan Plateau, as known as "roof of the world", was created through the on-going continent-continent collision between the Indian and Eurasian plates since 55 Ma. As the process continues, the plateau is growing both vertically and horizontally. The horizontal expansion of the plateau is blocked by the Yangtze block in the east, the Tarim block in the north, and the Ordos block in the northeast, and consequently lead to the formation of the circum Tibetan plateau orogenic belts. To better understand the mechanism behind this process, we conducted a comparative study by collecting 7 magnetotelluric (MT) profiles over the margins of the Tibetan plateau, namely, the INDEPTH 100, 700 and 800 lines in the southern Tibet, the INDEPTH 4000 and 5000 lines across the Altyn Tagh fault on the northern margin of the plateau, as well as other two profiles across the Haiyuan fault and the Longmenshan fault on the northeastern and eastern margins of the plateau deployed under the framework of project SinoProbe. The electrical features of the stable blocks surrounding the Tibetan plateau are generally resistive, while crustal conductive layers are found to be wide spread within the plateau. The southern margin of the Tibetan plateau is characterized by large scale underthrust of the Indian lithosphere beneath the plateau. This intense converging process created the thrust fault system distributed along the southern margin of the Tibetan plateau over 1000 km. Crustal conductive layers discovered in southern Tibet are generally associated with the southward crustal flow that originated from the lower crust within the plateau and exhumed along the thrust belts in the Himalayas. On the eastern margin of the Tibetan plateau, the electrical structures suggest that the Yangtze block wedged into the Tibetan lithosphere and caused decoupling between the crust and upper mantel. Large scale conductors discovered beneath the Songpan-Ganze block reflect that the eastward crustal flow was blocked and piled up along the eastern margin of the plateau due to the block of the Sichuan Basin, which further result in the uplift and expansion of the eastern Tibetan plateau. The northeastern and northern margins of the Tibetan plateau is bounded by large scale left-lateral strike-slip Haiyuan and Altyn Tagh faults. In these regions, the plateau interacts with the surrounding stable blocks in a way of oblique strike-slip. The deformation of the northern Tibetan lithosphere is dominated by crustal thickening, where no features of decoupling or large scale underthrusting were seen. Crustal conductors in these regions are generally not very well connected, which suggest the absence of crustal flow. Deep metamorphism fluids could be an alternative interpretation of the crustal conductors in these regions. * This work was jointly supported by the grants from Project SinoProbe-02-04 and National Natural Science Foundation of China (41404060).

Major Holocene block-and-ash fan at the western slope of ice-capped Pico de Orizaba volcano, México: Implications for future hazards

NASA Astrophysics Data System (ADS)

Siebe, Claus; Abrams, Michael; Sheridan, Michael F.

1993-12-01

A major block-and-ash fan extends more than 14 km westward from the summit of Pico de Orizaba volcano in the eastern part of the Trans-Mexican Volcanic Belt. Radiocarbon dating of charcoal within the fan deposits yielded Holocene ages that range between 4040 ± 80 and 4660 ± 100 y.B.P. Stratigraphical, sedimentological, geochemical, and scanning electron microscope studies indicate that this fan originated within a relatively short time-span by multiple volcanic explosions at the summit crater. This activity produced a series of pyroclastic flows (mainly block-and-ash flows) and lahars which were channelized by a glacial cirque and connecting U-shaped valleys as they descended toward the base of the volcano. A recurrence of a similar eruption today would pose severe hazards to the population of more than 50,000 people, who live in a potentially dangerous zone. A detailed reconstruction of the sequence of events that led to the formation of the block-and-ash fan is presented to help mitigate the risk. Special attention is given to the effects of an ice-cap and the role of pre-existing glacial morphology on the distribution of products from such an eruption.

Conversion and comparison of the mathematical, three-dimensional, finite-difference, ground-water flow model to the modular, three-dimensional, finite-difference, ground-water flow model for the Tesuque aquifer system in northern New Mexico

USGS Publications Warehouse

Umari, A.M.; Szeliga, T.L.

1989-01-01

The three-dimensional finite-difference groundwater model (using a mathematical groundwater flow code) of the Tesuque aquifer system in northern New Mexico was converted to run using the U.S. Geological Survey 's modular groundwater flow code. Results from the final versions of the predevelopment and 1947 to 2080 transient simulations of the two models are compared. A correlation coefficient of 0.9905 was obtained for the match in block-by-block head-dependent fluxes for predevelopment conditions. There are, however, significant differences in at least two specific cases. In the first case, a difference is associated with the net loss from the Pojoaque River and its tributaries to the aquifer. The net loss by the river is given as 1.134 cu ft/sec using the original groundwater model, which is 38.1% less than the net loss by the river of 1.8319 cu ft/sec computed in this study. In the second case, the large difference is computed for the transient decline in the hydraulic head of a model block near Tesuque Pueblo. The hydraulic-head decline by 2080 is, using the original model, 249 ft, which is 14.7% less than the hydraulic head of 292 ft computed by this study. In general, the differences between the two sets of results are not large enough to lead to different conclusions regarding the behavior of the system at steady state or when pumped. (USGS)

Numerical simulation of groundwater flow in strongly anisotropic aquifers using multiple-point flux approximation method

NASA Astrophysics Data System (ADS)

Lin, S. T.; Liou, T. S.

2017-12-01

Numerical simulation of groundwater flow in anisotropic aquifers usually suffers from the lack of accuracy of calculating groundwater flux across grid blocks. Conventional two-point flux approximation (TPFA) can only obtain the flux normal to the grid interface but completely neglects the one parallel to it. Furthermore, the hydraulic gradient in a grid block estimated from TPFA can only poorly represent the hydraulic condition near the intersection of grid blocks. These disadvantages are further exacerbated when the principal axes of hydraulic conductivity, global coordinate system, and grid boundary are not parallel to one another. In order to refine the estimation the in-grid hydraulic gradient, several multiple-point flux approximation (MPFA) methods have been developed for two-dimensional groundwater flow simulations. For example, the MPFA-O method uses the hydraulic head at the junction node as an auxiliary variable which is then eliminated using the head and flux continuity conditions. In this study, a three-dimensional MPFA method will be developed for numerical simulation of groundwater flow in three-dimensional and strongly anisotropic aquifers. This new MPFA method first discretizes the simulation domain into hexahedrons. Each hexahedron is further decomposed into a certain number of tetrahedrons. The 2D MPFA-O method is then extended to these tetrahedrons, using the unknown head at the intersection of hexahedrons as an auxiliary variable along with the head and flux continuity conditions to solve for the head at the center of each hexahedron. Numerical simulations using this new MPFA method have been successfully compared with those obtained from a modified version of TOUGH2.

WRF Simulation of the Genesis of Hurricane Javier (2004) in the Eastern Pacific

NASA Technical Reports Server (NTRS)

Braun, Scott A.

2005-01-01

The Eastern Pacific has the highest frequency of genesis events per unit area of any region worldwide (Elsberry et al 1987). African easterly waves, mesoscale convective systems (MCSs), and topographic effects are thought to play roles in the genesis of tropical cyclones there (Frank and Clark 1980, Velasco and Fritsch 1987, Zehnder 1991, Zehnder and Gall 1991; Farfan and Zehnder 1997). Mozer and Zehnder (1996), using dry, idealized simulations of flow past a large-scale three-dimensional mountain range comparable to the Sierra Madre Mountains of Mexico, showed that upstream flow blocking led to diversion of the flow primarily to the south of the mountains. This flow diversion led to the formation of a low-level, barotropically unstable jet (at a location comparable to the Isthmus of Tehuantepec) and the continuous formation of synoptic-scale vorticity maxima, which they suggested may play a role in tropical cyclogenesis. Farfan and Zehnder (1 997) examined the synoptic-scale circulations that led to the formation of Hurricane Guillermo (1991). Using numerical simulations, they found that flow blocking led to the formation of a low-level easterly jet south of the mountains of Central America and a northeasterly (gap flow) jet over the Gulf of Tehuantepec, which combined with the flow associated with the Intertropical Convergence Zone (ITCZ) to produce a closed cyclonic circulation in the location of Guillermo s formation. As will be discussed in this paper, the evolution of the flow field that was associated with the genesis of Hurricane Javier was similar to that described in Farfan and Zehnder (1997), with well-defined topographic flow features. Here, using a high- resolution simulation with the WRF model, we investigate whether these topographically induced flows played a significant role in the genesis of Javier.

Vertical-Axis Rotations Within Columbia River Basalt Flows Define a Sharp Eastern Boundary of the Coast Range Block with Potentially Increased Seismic Risk for Portland, Oregon

NASA Astrophysics Data System (ADS)

Hagstrum, J. T.; Wells, R. E.; Evarts, R. C.; Blakely, R. J.; Beeson, M. H.

2006-12-01

Paleomagnetic analysis of the Miocene Columbia River Basalt Group (CRBG) in the northern Willamette Valley of Oregon was undertaken as part of a larger mapping and hydrogeologic investigation of the CRBG's internal stratigraphy and structure. Differences in paleomagnetic directions between flows due to geomagnetic reversals and paleosecular variation, in combination with geochemical data, provide the most reliable means of flow identification. In addition, vertical-axis rotations between CRBG sites in the Portland area and sampling localities within the same flow units on the relatively stable Columbia Plateau were calculated. Clockwise rotations for sites within the northern Willamette Valley are remarkably consistent and have a weighted mean of 29°±3° (N=94). Available paleomagnetic data from CRBG sites along the Oregon coast at Cape Lookout (19°±22°, N=4) and Cape Foulweather (29°±18°, N=4) show similar results. East of the Portland Hills fault zone along the Columbia River Gorge, however, clockwise rotations are much less averaging 12°±3° (N=15). North of Portland, the CRBG rotational values drop abruptly from ~29° to 6°±17° (N=3) across an unnamed fault near Woodland, WA, identified using aeromagnetic data; to the south, the values drop from ~29° to 18°±3° (N=6) across the Mt. Angel-Gales Creek fault zone east of Salem, OR. The eastern boundary of the Oregon Coast Range block is thus defined by three offset NW-trending fault segments, with the offsets corresponding to the Portland and Willamette pull-apart basins. North of the Coast Range block's northern boundary, which is roughly coincident with the Columbia River, CRBG rotations also are about half that (15°±3°, N=15) found within the block. Northward movement and clockwise rotation of the Oregon Coast Range block have previously been modeled as decreasing continuously eastward to the Columbia Plateau. Our new paleomagnetic data indicate an abrupt step down of rotational values by half in the vicinity of the Portland metropolitan area, and that the Portland Hills-Clackamas River and other parallel structural zones could be the loci of larger and more dangerous strike-slip earthquakes than previously thought.

Wind-tunnel experiments of turbulent flow over a surface-mounted 2-D block in a thermally-stratified boundary layer

NASA Astrophysics Data System (ADS)

Zhang, Wei; Markfort, Corey; Porté-Agel, Fernando

2014-11-01

Turbulent flows over complex surface topography have been of great interest in the atmospheric science and wind engineering communities. The geometry of the topography, surface roughness and temperature characteristics as well as the atmospheric thermal stability play important roles in determining momentum and scalar flux distribution. Studies of turbulent flow over simplified topography models, under neutrally stratified boundary-layer conditions, have provided insights into fluid dynamics. However, atmospheric thermal stability has rarely been considered in laboratory experiments, e.g., wind-tunnel experiments. Series of wind-tunnel experiments of thermally-stratified boundary-layer flow over a surface-mounted 2-D block, in a well-controlled boundary-layer wind tunnel, will be presented. Measurements using high-resolution PIV, x-wire/cold-wire anemometry and surface heat flux sensors were conducted to quantify the turbulent flow properties, including the size of the recirculation zone, coherent vortex structures and the subsequent boundary layer recovery. Results will be shown to address thermal stability effects on momentum and scalar flux distribution in the wake, as well as dominant mechanism of turbulent kinetic energy generation and consumption. The authors gratefully acknowledge funding from the Swiss National Foundation (Grant 200021-132122), the National Science Foundation (Grant ATM-0854766) and NASA (Grant NNG06GE256).

A combined approach to physical vulnerability of large cities exposed to natural hazards - the case study of Arequipa, Peru

NASA Astrophysics Data System (ADS)

Thouret, Jean-Claude; Ettinger, Susanne; Zuccaro, Giulio; Guitton, Mathieu; Martelli, Kim; Degregorio, Daniela; Nardone, Stefano; Santoni, Olivier; Magill, Christina; Luque, Juan Alexis; Arguedas, Ana

2013-04-01

Arequipa, the second largest city in Peru with almost one million inhabitants, is exposed to various natural hazards, such as earthquakes, landslides, flash floods, and volcanic eruptions. This study focuses on the vulnerability and response of housing, infrastructure and lifelines in Arequipa to flash floods and eruption induced hazards, notably lahars from El Misti volcano. We propose a combined approach for assessing physical vulnerability in a large city based on: (1) remote sensing utilizing high-resolution imagery (SPOT5, Google Earth Pro, Bing, Pléïades) to map the distribution and type of land use, properties of city blocks in terms of exposure to the hazard (elevation above river level, distance to channel, impact angle, etc.); (2) in situ survey of buildings and critical infrastructure (e.g., bridges) and strategic resources (e.g., potable water, irrigation, sewage); (3) information gained from interviews with engineers involved in construction works, previous crises (e.g., June 2001 earthquake) and risk mitigation in Arequipa. Remote sensing and mapping at the scale of the city has focused on three pilot areas, along the perennial Rio Chili valley that crosses the city and oasis from north to south, and two of the east-margin tributaries termed Quebrada (ravine): San Lazaro crossing the northern districts and Huarangal crossing the northeastern districts. Sampling of city blocks through these districts provides varying geomorphic, structural, historical, and socio-economic characteristics for each sector. A reconnaissance survey included about 900 edifices located in 40 city blocks across districts of the pilot areas, distinct in age, construction, land use and demographics. A building acts as a structural system and its strength and resistance to flashfloods and lahars therefore highly depends on the type of construction and the used material. Each building surveyed was assigned to one of eight building categories based on physical criteria (dominant building materials, number of floors, percentage and quality of openings, etc). Future steps in this study include mapping potential impacts from flash flood and lahars as a function of frequency of occurrence and magnitude. For this purpose, we will regroup the eight building types identified in Arequipa to obtain a reduced number of vulnerability categories. Fragility functions will then be established for each vulnerability category and hazard relating percentage damage to parameters such as flow velocity, depth, and dynamic and hydrostatic pressure. These functions will be applied to flow simulations for each of the three river channels considered with the final goal to determine potential losses, identify areas of particularly high risk and to prepare plans for evacuation, relocation and rehabilitation. In the long term, this investigation aims to contribute towards a multi-hazard risk analysis including earthquake- and other volcanic hazards, e.g. ashfall and pyroclastic flows, all by considering the cascading effects of a hazard chain. We also plan to address the consequences of failure of two artificial lake dams located 40 and 70 km north of the city. A lake breakout flood or lahar would propagate beyond the city and would call for an immediate response including contingency plans and evacuation practices.

Modeling and Grid Generation of Iced Airfoils

NASA Technical Reports Server (NTRS)

Vickerman, Mary B.; Baez, Marivell; Braun, Donald C.; Hackenberg, Anthony W.; Pennline, James A.; Schilling, Herbert W.

2007-01-01

SmaggIce Version 2.0 is a software toolkit for geometric modeling and grid generation for two-dimensional, singleand multi-element, clean and iced airfoils. A previous version of SmaggIce was described in Preparing and Analyzing Iced Airfoils, NASA Tech Briefs, Vol. 28, No. 8 (August 2004), page 32. To recapitulate: Ice shapes make it difficult to generate quality grids around airfoils, yet these grids are essential for predicting ice-induced complex flow. This software efficiently creates high-quality structured grids with tools that are uniquely tailored for various ice shapes. SmaggIce Version 2.0 significantly enhances the previous version primarily by adding the capability to generate grids for multi-element airfoils. This version of the software is an important step in streamlining the aeronautical analysis of ice airfoils using computational fluid dynamics (CFD) tools. The user may prepare the ice shape, define the flow domain, decompose it into blocks, generate grids, modify/divide/merge blocks, and control grid density and smoothness. All these steps may be performed efficiently even for the difficult glaze and rime ice shapes. Providing the means to generate highly controlled grids near rough ice, the software includes the creation of a wrap-around block (called the "viscous sublayer block"), which is a thin, C-type block around the wake line and iced airfoil. For multi-element airfoils, the software makes use of grids that wrap around and fill in the areas between the viscous sub-layer blocks for all elements that make up the airfoil. A scripting feature records the history of interactive steps, which can be edited and replayed later to produce other grids. Using this version of SmaggIce, ice shape handling and grid generation can become a practical engineering process, rather than a laborious research effort.

Core microstructure, morphology and chain arrangement of block copolymer self-assemblies as investigated by thermal field-flow fractionation.

PubMed

Muza, U L; Greyling, G; Pasch, H

2018-08-10

The self-assembly of block copolymers (BCPs), as a result of solvent selectivity for one block, has recently received significant attention due to novel applications of BCPs in pharmaceuticals, biomedicine, cosmetics, electronics and nanotechnology. The correlation of BCP microstructure and the structure of the resulting self-assemblies requires advanced analytical methods. However, traditional bulk characterization techniques are limited in the quest of providing detailed information regarding molar mass (M w ), hydrodynamic size (D h ), chemical composition, and morphology for these self-assemblies. In the present study, thermal field-flow fractionation (ThFFF) is utilised to investigate the impact of core microstructure on the resultant solution properties of vesicles prepared from polystyrene-polybutadiene block copolymers (PS-b-PBd) with 1.2- and 1.4-polybutadiene blocks, respectively. As compared to investigations on the impact of the corona microstructure, the impact of core microstructure on micellar properties has largely been neglected in previous work. In N,N-dimethylacetamide (DMAc) these BCPs form vesicles having PS shells and PBd cores. D h , M w , aggregation number, and critical micelle concentration of these micelles are shown to be sensitive to the core microstructure, therefore, demonstrating the potential of microstructural differences to be used for providing tuneable pathways to specific self-assemblies. It is shown that micelles prepared from BCPs of similar PS and PBd block sizes are successfully separated by ThFFF. It is further demonstrated in this study that PS-b-PBd vesicles and PS homopolymers of identical surface chemistry (PS) and comparable D h in DMAc, can be separated by ThFFF. Copyright © 2018 Elsevier B.V. All rights reserved.

Comparison of numerical and experimental results of the flow in the U9 Kaplan turbine model

NASA Astrophysics Data System (ADS)

Petit, O.; Mulu, B.; Nilsson, H.; Cervantes, M.

2010-08-01

The present work compares simulations made using the OpenFOAM CFD code with experimental measurements of the flow in the U9 Kaplan turbine model. Comparisons of the velocity profiles in the spiral casing and in the draft tube are presented. The U9 Kaplan turbine prototype located in Porjus and its model, located in Älvkarleby, Sweden, have curved inlet pipes that lead the flow to the spiral casing. Nowadays, this curved pipe and its effect on the flow in the turbine is not taken into account when numerical simulations are performed at design stage. To study the impact of the inlet pipe curvature on the flow in the turbine, and to get a better overview of the flow of the whole system, measurements were made on the 1:3.1 model of the U9 turbine. Previously published measurements were taken at the inlet of the spiral casing and just before the guide vanes, using the laser Doppler anemometry (LDA) technique. In the draft tube, a number of velocity profiles were measured using the LDA techniques. The present work extends the experimental investigation with a horizontal section at the inlet of the draft tube. The experimental results are used to specify the inlet boundary condition for the numerical simulations in the draft tube, and to validate the computational results in both the spiral casing and the draft tube. The numerical simulations were realized using the standard k-e model and a block-structured hexahedral wall function mesh.

The Effects Of Urban Landscape Patterns On Rainfall-Runoff Processes At Small Scale

NASA Astrophysics Data System (ADS)

Chen, L.

2016-12-01

Many studies have indicated that urban landscape change may alter rainfall-runoff processes. However, how urban landscape pattern affect this process is little addressed. In this study, the hydrological effects of landscape pattern on rainfall-runoff processes at small-scale was explored. Twelve residential blocks with independent drainage systems in Beijing were selected as case study areas. Impervious metrics of these blocks, i.e., total impervious area (TIA) and directly connected impervious area (DCIA), were identified. A drainage index describing catchment general drainage load and the overland flow distance, Ad, was estimated and used as one of the landscape spatial metrics. Three scenarios were designed to test the potential influence of impervious surface pattern on runoff processes. Runoff variables including total and peak runoff depth (Qt and Qp) were simulated under different rainfall conditions by Storm Water Management Model (SWMM). The relationship between landscape patterns and runoff variables were analyzed, and further among the three scenarios. The results demonstrated that, in small urban blocks, spatial patterns have inherent influences on rainfall-runoff processes. Specifically, (1) Imperviousness acts as effective indicators in predicting both Qt and Qp. As rainfall intensity increases, the major affecting factor changes from DCIA to TIA for both Qt and Qp; (2) Increasing the size of drainage area dominated by each drainage inlet will benefit the block peak flow mitigation; (3) Different spatial concentrations of impervious surfaces have inherent influences on Qp, when impervious surfaces located away from the outlet can reduce the peak flow discharge. These findings may provide insights into the role of urban landscape patterns in driving rainfall-runoff responses in urbanization, which is essential for urban planning and stormwater management.

Integration of geology, geostatistics, well logs and pressure data to model a heterogeneous supergiant field in Iran

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

Samimi, B.; Bagherpour, H.; Nioc, A.

1995-08-01

The geological reservoir study of the supergiant Ahwaz field significantly improved the history matching process in many aspects, particularly the development of a geostatistical model which allowed a sound basis for changes and by delivering much needed accurate estimates of grid block vertical permeabilities. The geostatistical reservoir evaluation was facilitated by using the Heresim package and litho-stratigraphic zonations for the entire field. For each of the geological zones, 3-dimensional electrolithofacies and petrophysical property distributions (realizations) were treated which captured the heterogeneities which significantly affected fluid flow. However, as this level of heterogeneity was at a significantly smaller scale than themore » flow simulation grid blocks, a scaling up effort was needed to derive the effective flow properties of the blocks (porosity, horizontal and vertical permeability, and water saturation). The properties relating to the static reservoir description were accurately derived by using stream tube techniques developed in-house whereas, the relative permeabilities of the grid block were derived by dynamic pseudo relative permeability techniques. The prediction of vertical and lateral communication and water encroachment was facilitated by a close integration of pressure, saturation data, geostatistical modelling and sedimentological studies of the depositional environments and paleocurrents. The nature of reservoir barriers and baffles varied both vertically and laterally in this heterogeneous reservoir. Maps showing differences in pressure between zones after years of production served as a guide to integrating the static geological studies to the dynamic behaviour of each of the 16 reservoir zones. The use of deep wells being drilled to a deeper reservoir provided data to better understand the sweep efficiency and the continuity of barriers and baffles.« less

Unilateral spinal anesthesia using low-flow injection through a 29-gauge Quincke needle.

PubMed

Meyer, J; Enk, D; Penner, M

1996-06-01

Restriction of sympathetic denervation during spinal anesthesia may minimize hemodynamic alterations. Theoretically, the use of nonisobaric anesthetics may allow unilateral anesthesia and thus restrict sympathetic denervation to one side of the body. The present prospective study investigates the incidence of unilateral spinal anesthesia using hyperbaric bupivacaine 0.5% (1.4 mL, 1.6 mL, 1.8 mL, or 2.0 mL) injected via a 29-gauge Quincke needle with a pump-controlled injection flow of 1 mL/min. In 96 consecutive patients undergoing unilateral surgery of the lower extremities, spinal anesthesia was performed in the lateral decubitus position, which was maintained for 20 min postinjection. Increases in foot temperature of at least 0.5 degrees C were defined as sympathetic blockade. The incidence of unilateral block was not significantly influenced by the amount of bupivacaine. For all 96 patients, the incidence of unilateral sympathetic and complete motor block was 69% and 77%, respectively. Frequency of unilateral sensory block (assessed by pinprick and temperature discrimination) was significantly lower (28%). Strict unilateral spinal anesthesia was achieved in 24 cases (25%). Twenty minutes after injection of the local anesthetic, mean arterial blood pressure decreased significantly in patients with bilateral sympathetic blockade from 87 +/- 8 to 83 +/- 8 mm Hg (P < 0.01) but not in patients with unilateral sympathetic blockade (from 87 +/- 11 to 85 +/- 10 mm Hg). In conclusion, low-flow injection (1 mL/min) of hyperbaric bupivacaine 0.5% via a 29-gauge Quincke needle prevented bilateral sympathetic blockade in more than 69% of the patients. The data further suggest that loss of temperature discrimination alone is not a reliable estimation of sympathetic block.

Pāhoehoe, `a`ā, and block lava: an illustrated history of the nomenclature

NASA Astrophysics Data System (ADS)

Harris, Andrew J. L.; Rowland, Scott K.; Villeneuve, Nicolas; Thordarson, Thor

2017-01-01

Lava flows occur worldwide, and throughout history, various cultures (and geologists) have described flows based on their surface textures. As a result, surface morphology-based nomenclature schemes have been proposed in most languages to aid in the classification and distinction of lava surface types. One of the first to be published was likely the nine-class, Italian-language description-based classification proposed by Mario Gemmellaro in 1858. By far, the most commonly used terms to describe lava surfaces today are not descriptive but, instead, are merely words, specifically the Hawaiian words `a`ā (rough brecciated basalt lava) and pāhoehoe (smooth glassy basalt lava), plus block lava (thick brecciated lavas that are typically more silicic than basalt). `A`ā and pāhoehoe were introduced into the Western geological vocabulary by American geologists working in Hawai`i during the 1800s. They and other nineteenth century geologists proposed formal lava-type classification schemes for scientific use, and most of them used the Hawaiian words. In 1933, Ruy Finch added the third lava type, block lava, to the classification scheme, with the tripartite system being formalized in 1953 by Gordon Macdonald. More recently, particularly since the 1980s and based largely on studies of lava flow interiors, a number of sub-types and transitional forms of all three major lava types have been defined. This paper reviews the early history of the development of the pāhoehoe, `a`ā, and block lava-naming system and presents a new descriptive classification so as to break out the three parental lava types into their many morphological sub-types.

Atmospheric blocking as a traffic jam in the jet stream

NASA Astrophysics Data System (ADS)

Nakamura, N.; Huang, S. Y.

2017-12-01

It is demonstrated using the ERA-Interim product that synoptic to intraseasonal variabilities of extratropical circulation in the boreal storm track regions are strongly affected by the zonal convergence of the column-integrated eastward flux of local wave activity (LWA). In particular, from the multi-year daily samples of LWA fluxes, we find that the wintertime zonal LWA flux in the jet exit regions tends to maximize for an intermediate value of column-averaged LWA. This is because an increasing LWA decelerates the zonal flow, eventually weakening the eastward advection of LWA. From theory we argue that large wave events on the decreasing side of the flux curve with increasing LWA cannot be maintained as a stable steady state. Consistent with this argument, observed states corresponding to that side of flux curve often exhibit local wave breaking and blocking events. A close parallelism exists for the traffic flow problem, in which the traffic flux (traffic density times traffic speed) is often observed to maximize for an intermediate value of traffic density. This is because the traffic speed is controlled not only by the imposed speed limit but also by the traffic density — an increasingly heavy traffic slows down the flow naturally and eventually decreases the flux. Once the flux starts to decrease with an increasing traffic density, a traffic jam kicks in suddenly (Lighthill and Whitham 1955, Richards 1956). The above idea is demonstrated by a simple conceptual model based on the equivalent barotropic PV contour design (Nakamura and Huang 2017, JAS), which predicts a threshold of blocking onset. The idea also suggests that the LWA that gives the `flux capacity,' i.e., the maximum LWA flux at a given location, is a useful predictor of local wave breaking/block formation.

Tilted middle Tertiary ash-flow calderas and subjacent granitic plutons, southern Stillwater Range, Nevada: cross sections of an Oligocene igneous center

USGS Publications Warehouse

John, D.A.

1995-01-01

Steeply tilted late Oligocene caldera systems in the Stillwater caldera complex record a number of unusual features including extreme thickness of caldera-related deposits, lack of evidence for structural doming of the calderas and preservation of vertical compositional zoning in the plutonic rocks. The Stillwater caldera complex comprises three partly overlapping ash-flow calderas and subjacent plutonic rocks that were steeply tilted during early Miocene extension. The Job Canyon caldera, the oldest (ca. 29-28 Ma) caldera, consists of two structural blocks. The 25 to 23 Ma Poco Canyon and Elevenmile Canyon calderas and underlying Freeman Creek pluton overlap in time and space with each other. Caldera collapse occurred mostly along subvertical ring-fracture faults that penetrated to depths of >5 km and were repeatedly active during eruption of ash-flow tuffs. The calderas collapsed as large piston-like blocks, and there is no evidence for chaotic collapse. Preserved parts of caldera floors are relatively flat surfaces several kilometers across. -from Author

Implicit high-order discontinuous Galerkin method with HWENO type limiters for steady viscous flow simulations

NASA Astrophysics Data System (ADS)

Jiang, Zhen-Hua; Yan, Chao; Yu, Jian

2013-08-01

Two types of implicit algorithms have been improved for high order discontinuous Galerkin (DG) method to solve compressible Navier-Stokes (NS) equations on triangular grids. A block lower-upper symmetric Gauss-Seidel (BLU-SGS) approach is implemented as a nonlinear iterative scheme. And a modified LU-SGS (LLU-SGS) approach is suggested to reduce the memory requirements while retain the good convergence performance of the original LU-SGS approach. Both implicit schemes have the significant advantage that only the diagonal block matrix is stored. The resulting implicit high-order DG methods are applied, in combination with Hermite weighted essentially non-oscillatory (HWENO) limiters, to solve viscous flow problems. Numerical results demonstrate that the present implicit methods are able to achieve significant efficiency improvements over explicit counterparts and for viscous flows with shocks, and the HWENO limiters can be used to achieve the desired essentially non-oscillatory shock transition and the designed high-order accuracy simultaneously.

Graphene Nanopore Support System for Simultaneous High-Resolution AFM Imaging and Conductance Measurements

PubMed Central

2015-01-01

Accurately defining the nanoporous structure and sensing the ionic flow across nanoscale pores in thin films and membranes has a wide range of applications, including characterization of biological ion channels and receptors, DNA sequencing, molecule separation by nanoparticle films, sensing by block co-polymers films, and catalysis through metal–organic frameworks. Ionic conductance through nanopores is often regulated by their 3D structures, a relationship that can be accurately determined only by their simultaneous measurements. However, defining their structure–function relationships directly by any existing techniques is still not possible. Atomic force microscopy (AFM) can image the structures of these pores at high resolution in an aqueous environment, and electrophysiological techniques can measure ion flow through individual nanoscale pores. Combining these techniques is limited by the lack of nanoscale interfaces. We have designed a graphene-based single-nanopore support (∼5 nm thick with ∼20 nm pore diameter) and have integrated AFM imaging and ionic conductance recording using our newly designed double-chamber recording system to study an overlaid thin film. The functionality of this integrated system is demonstrated by electrical recording (<10 pS conductance) of suspended lipid bilayers spanning a nanopore and simultaneous AFM imaging of the bilayer. PMID:24581087

Elastic contact mechanics: percolation of the contact area and fluid squeeze-out.

PubMed

Persson, B N J; Prodanov, N; Krick, B A; Rodriguez, N; Mulakaluri, N; Sawyer, W G; Mangiagalli, P

2012-01-01

The dynamics of fluid flow at the interface between elastic solids with rough surfaces depends sensitively on the area of real contact, in particular close to the percolation threshold, where an irregular network of narrow flow channels prevails. In this paper, numerical simulation and experimental results for the contact between elastic solids with isotropic and anisotropic surface roughness are compared with the predictions of a theory based on the Persson contact mechanics theory and the Bruggeman effective medium theory. The theory predictions are in good agreement with the experimental and numerical simulation results and the (small) deviation can be understood as a finite-size effect. The fluid squeeze-out at the interface between elastic solids with randomly rough surfaces is studied. We present results for such high contact pressures that the area of real contact percolates, giving rise to sealed-off domains with pressurized fluid at the interface. The theoretical predictions are compared to experimental data for a simple model system (a rubber block squeezed against a flat glass plate), and for prefilled syringes, where the rubber plunger stopper is lubricated by a high-viscosity silicon oil to ensure functionality of the delivery device. For the latter system we compare the breakloose (or static) friction, as a function of the time of stationary contact, to the theory prediction.

Horizontal visibility graphs generated by type-I intermittency

NASA Astrophysics Data System (ADS)

Núñez, Ángel M.; Luque, Bartolo; Lacasa, Lucas; Gómez, Jose Patricio; Robledo, Alberto

2013-05-01

The type-I intermittency route to (or out of) chaos is investigated within the horizontal visibility (HV) graph theory. For that purpose, we address the trajectories generated by unimodal maps close to an inverse tangent bifurcation and construct their associated HV graphs. We show how the alternation of laminar episodes and chaotic bursts imprints a fingerprint in the resulting graph structure. Accordingly, we derive a phenomenological theory that predicts quantitative values for several network parameters. In particular, we predict that the characteristic power-law scaling of the mean length of laminar trend sizes is fully inherited by the variance of the graph degree distribution, in good agreement with the numerics. We also report numerical evidence on how the characteristic power-law scaling of the Lyapunov exponent as a function of the distance to the tangent bifurcation is inherited in the graph by an analogous scaling of block entropy functionals defined on the graph. Furthermore, we are able to recast the full set of HV graphs generated by intermittent dynamics into a renormalization-group framework, where the fixed points of its graph-theoretical renormalization-group flow account for the different types of dynamics. We also establish that the nontrivial fixed point of this flow coincides with the tangency condition and that the corresponding invariant graph exhibits extremal entropic properties.

Mesofauna Influence on Humification Process of Vegetable Oddments with Participation Microarthropod

ERIC Educational Resources Information Center

Simonov, Yuriy V.; Svetkina, Irina A.; Kryuchkov, Konstantin V.

2016-01-01

Relevance of the studied problem is caused by the fact that stability of natural ecosystems strongly depends on functioning of their destructive block which closes a biological circulation. The organisms that ensure functioning of the destructive block are very different and numerous. All of them partly supplement, partly duplicate functions of…

Mass transport-related stratal disruption and sedimentary products

NASA Astrophysics Data System (ADS)

Ogata, Kei; Mutti, Emiliano; Tinterri, Roberto

2010-05-01

From an outcrop perspective, mass transport deposit are commonly represented by "chaotic" units, characterized by dismembered and internally deformed slide blocks of different sizes and shapes, embedded in a more or less abundant fine-grained matrix. The large amount of data derived from geophysical investigations of modern continental margins have permitted the characterization of the overall geometry of many of these deposits, which, however, remain still relatively poorly described from outcrop studies of collisional basins. Results of this work show that in mass-transport deposits an unsorted, strongly mixed, relatively fine-grained clastic matrix almost invariably occurs in irregularly interconnected patches and pseudo-veins, infilling space between large clasts and blocks. We interpreted the aspect of this matrix as typical of a liquefied mixture of water and sediment, characterized by an extremely high mobility due to overpressured conditions, as evidenced by both lateral and vertical injections. On a much larger scale this kind of matrix is probably represented by the seismically "transparent" facies separating slide blocks of many mass-transport deposits observed in seismic-reflection profiles. The inferred mechanism of matrix production suggests a progressive soft-sediment deformation, linked to different phases of submarine landslide evolution (i.e. triggering, translation, accumulation and post-depositional stages), leading to an almost complete stratal disruption within the chaotic units. From our data we suggest that most submarine landslides move because of the development of ductile shear zones marked by the presence of "overpressured" matrix, both internally and along the basal surface. The matrix acts as a lubricating medium, accommodating friction forces and deformation, thus permitting the differential movement of discrete internal portions and enhancing the submarine slide mobility. Based on our experience, we suggest that this kind of deposit is quite common in the sedimentary record though still poorly reported and understood. Mutti and Carminatti (oral presentation from Mutti et al., 2006) have suggested to call these deposits "blocky-flow deposits", i.e. the deposit of a complex flow that is similar to a debris flow, or hyper-concentrated flow, except that it carries also out-size coherent and internally deformed blocks (meters to hundreds of meters across) usually arranged in isolated slump folds. The origin of blocky flows is difficult to understand on presently available data, particularly because it involves the contemporary origin of coherent slide blocks and a plastic flow that carries them as floating elements over considerable run-out distances. The recognition of the above-mentioned characteristics should be a powerful tool to discriminate sedimentary and tectonic "chaotic" units within accretionary systems, and to distinguish submarine landslide deposits transported as catastrophic blocky flows (and therefore part of the broad family of sediment gravity flows) from those in which transport took place primarily along shear planes (i.e. slumps, coherent slides), also highlighting a possible continuum from slides to turbidity currents. The discussed examples fall into a broad category of submarine slide deposits ranging from laterally extensive carbonate megabreccias (lower-middle Eocene "megaturbidites" of the south-central Pyrenees), to mass transport deposits with a very complex internal geometry developed in a highly tectonically mobile basin (upper Eocene - lower Oligocene Ranzano Sandstone, northern Apennines). References: Mutti, E., Carminatti, M., Moreira, J.L.P. & Grassi, A.A. (2006) - Chaotic Deposits: examples from the Brazilian offshore and from outcrop studies in the Spanish Pyrenees and Northern Apennines, Italy. - A.A.P.G. Annual Meeting, April 9-12, Houston, Texas.

A large eddy simulation scheme for turbulent reacting flows

NASA Technical Reports Server (NTRS)

Gao, Feng

1993-01-01

The recent development of the dynamic subgrid-scale (SGS) model has provided a consistent method for generating localized turbulent mixing models and has opened up great possibilities for applying the large eddy simulation (LES) technique to real world problems. Given the fact that the direct numerical simulation (DNS) can not solve for engineering flow problems in the foreseeable future (Reynolds 1989), the LES is certainly an attractive alternative. It seems only natural to bring this new development in SGS modeling to bear on the reacting flows. The major stumbling block for introducing LES to reacting flow problems has been the proper modeling of the reaction source terms. Various models have been proposed, but none of them has a wide range of applicability. For example, some of the models in combustion have been based on the flamelet assumption which is only valid for relatively fast reactions. Some other models have neglected the effects of chemical reactions on the turbulent mixing time scale, which is certainly not valid for fast and non-isothermal reactions. The probability density function (PDF) method can be usefully employed to deal with the modeling of the reaction source terms. In order to fit into the framework of LES, a new PDF, the large eddy PDF (LEPDF), is introduced. This PDF provides an accurate representation for the filtered chemical source terms and can be readily calculated in the simulations. The details of this scheme are described.

Reconfiguration of a flexible fiber immersed in a 2D dense granular flow close to the jamming transition

NASA Astrophysics Data System (ADS)

Kolb, Evelyne; Algarra, Nicolas; Vandembroucq, Damien; Lazarus, Arnaud

2015-11-01

We propose a new fluid/structure interaction in the unusual case of a dense granular medium flowing against an elastic fibre acting as a flexible intruder. We experimentally studied the deflection of a mylar flexible beam clamped at one side, the other free side facing a 2D granular flow in a horizontal cell moving at a constant velocity. We investigated the reconfiguration of the fibre as a function of the fibre's rigidity and of the granular packing fraction close but below the jamming in 2D. Imposing the fibre geometry like its length or thickness sets the critical buckling force the fibre is able to resist if it was not supported by lateral grains, while increasing the granular packing fraction might laterally consolidate the fibre and prevent it from buckling. But on the other side, the approach to jamming transition by increasing the granular packing fraction will be characterized by a dramatically increasing size of the cluster of connected grains forming a solid block acting against the fibre, which might promote the fibre's deflection. Thus, we investigated the granular flow fields, the fibre's deflexion as well as the forces experienced by the fibre and compared them with theoretical predictions from elastica for different loadings along the fibre. PMMH, CNRS UMR 7636, UPMC, ESPCI-ParisTech, 10 rue Vauquelin, 75231 Paris Cedex 05, France.

Continuous flow real-time PCR device using multi-channel fluorescence excitation and detection.

PubMed

Hatch, Andrew C; Ray, Tathagata; Lintecum, Kelly; Youngbull, Cody

2014-02-07

High throughput automation is greatly enhanced using techniques that employ conveyor belt strategies with un-interrupted streams of flow. We have developed a 'conveyor belt' analog for high throughput real-time quantitative Polymerase Chain Reaction (qPCR) using droplet emulsion technology. We developed a low power, portable device that employs LED and fiber optic fluorescence excitation in conjunction with a continuous flow thermal cycler to achieve multi-channel fluorescence detection for real-time fluorescence measurements. Continuously streaming fluid plugs or droplets pass through tubing wrapped around a two-temperature zone thermal block with each wrap of tubing fluorescently coupled to a 64-channel multi-anode PMT. This work demonstrates real-time qPCR of 0.1-10 μL droplets or fluid plugs over a range of 7 orders of magnitude concentration from 1 × 10(1) to 1 × 10(7). The real-time qPCR analysis allows dynamic range quantification as high as 1 × 10(7) copies per 10 μL reaction, with PCR efficiencies within the range of 90-110% based on serial dilution assays and a limit of detection of 10 copies per rxn. The combined functionality of continuous flow, low power thermal cycling, high throughput sample processing, and real-time qPCR improves the rates at which biological or environmental samples can be continuously sampled and analyzed.

Beautiful Blocks of Bedrock

NASA Image and Video Library

2016-06-01

This image captured by NASA Mars Reconnaissance Orbiter spacecraft targets a 3-kilometer diameter crater that occurs within the ejecta blanket of the much older Bakhuysen Crater, a 150-kilometer diameter impact crater in Noachis Terra. Impact craters are interesting because they provide a mechanism to uplift and expose underlying bedrock, allowing for the study of the subsurface and the geologic past. An enhanced color image shows the wall of the crater, which exposes layering as well as blocks of rock. There is a distinctive large block in the upper left of the crater wall, generally referred to as a "mega-block." It is an angular, light-toned, highly fragmented block, about 100 meters across. Several smaller light-toned blocks are also in the crater wall, possibly of the same rock type as the "mega-block." Ejecta blocks are thrown outward during the initial excavation of a crater, or are deposited as part of the ground-hugging flows of which the majority of the ejecta blanket is comprised. Through images like these, we are able to study the deeper subsurface of Mars that is not otherwise exposed. http://photojournal.jpl.nasa.gov/catalog/PIA20728

Heart attack first aid

MedlinePlus

First aid - heart attack; First aid - cardiopulmonary arrest; First aid - cardiac arrest ... A heart attack occurs when the blood flow that carries oxygen to the heart is blocked. The heart muscle ...

Unsteady RANS/DES analysis of flow around helicopter rotor blades at forword flight conditions

NASA Astrophysics Data System (ADS)

Zhang, Zhenyu; Qian, Yaoru

2018-05-01

In this paper, the complex flows around forward-flying helicopter blades are numerically investigated. Both the Reynolds-averaged Navier-Stokes (RANS) and the Detached Eddy Simulation (DES) methods are used for the analysis of characteristics like local dynamic flow separation, effects of radial sweeping and reversed flow. The flow was solved by a highly efficient finite volume solver with multi-block structured grids. Focusing upon the complexity of the advance ratio effects, above properties are fully recognized. The current results showed significant agreements between both RANS and DES methods at phases with attached flow phases. Detailed information of separating flow near the withdrawal phases are given by DES results. The flow analysis of these blades under reversed flow reveals a significant interaction between the reversed flow and the span-wise sweeping.

A bio-inspired microstructure induced by slow injection moulding of cylindrical block copolymers.

PubMed

Stasiak, Joanna; Brubert, Jacob; Serrani, Marta; Nair, Sukumaran; de Gaetano, Francesco; Costantino, Maria Laura; Moggridge, Geoff D

2014-08-28

It is well known that block copolymers with cylindrical morphology show alignment with shear, resulting in anisotropic mechanical properties. Here we show that well-ordered bi-directional orientation can be achieved in such materials by slow injection moulding. This results in a microstructure, and anisotropic mechanical properties, similar to many natural tissues, making this method attractive for engineering prosthetic fibrous tissues. An application of particular interest to us is prosthetic polymeric heart valve leaflets, mimicking the shape, microstructure and hence performance of the native valve. Anisotropic layers have been observed for cylinder-forming block copolymers centrally injected into thin circular discs. The skin layers exhibit orientation parallel to the flow direction, whilst the core layer shows perpendicularly oriented domains; the balance of skin to core layers can be controlled by processing parameters such as temperature and injection rate. Heart valve leaflets with a similar layered structure have been prepared by injection moulding. Numerical modelling demonstrates that such complex orientation can be explained and predicted by the balance of shear and extensional flow.

Redistribution of blood within the body is important for thermoregulation in an ectothermic vertebrate (Crocodylus porosus).

PubMed

Seebacher, Frank; Franklin, Craig E

2007-11-01

Changes in blood flow are a principal mechanism of thermoregulation in vertebrates. Changes in heart rate will alter blood flow, although multiple demands for limited cardiac output may compromise effective thermoregulation. We tested the hypothesis that regional differences in blood flow during heating and cooling can occur independently from changes in heart rate. We measured heart rate and blood pressure concurrently with blood flow in the crocodile, Crocodylus porosus. We measured changes in blood flow by laser Doppler flowmetry, and by injecting coloured microspheres. All measurements were made under different heat loads, with and without blocking cholinergic and beta-adrenergic receptors (autonomic blockade). Heart rates were significantly faster during heating than cooling in the control animals, but not when autonomic receptors were blocked. There were no significant differences in blood flow distribution between the control and autonomic blockade treatments. In both treatments, blood flow was directed to the dorsal skin and muscle and away from the tail and duodenum during heating. When the heat source was switched off, there was a redistribution of blood from the dorsal surface to the duodenum. Blood flow to the leg skin and muscle, and to the liver did not change significantly with thermal state. Blood pressure was significantly higher during the autonomic blockade than during the control. Thermal time constants of heating and cooling were unaffected by the blockade of autonomic receptors. We concluded that animals partially compensated for a lack of differential heart rates during heating and cooling by redistributing blood within the body, and by increasing blood pressure to increase flow. Hence, measures of heart rate alone are insufficient to assess physiological thermoregulation in reptiles.

Assignment of boundary conditions in embedded ground water flow models

USGS Publications Warehouse

Leake, S.A.

1998-01-01

Many small-scale ground water models are too small to incorporate distant aquifer boundaries. If a larger-scale model exists for the area of interest, flow and head values can be specified for boundaries in the smaller-scale model using values from the larger-scale model. Flow components along rows and columns of a large-scale block-centered finite-difference model can be interpolated to compute horizontal flow across any segment of a perimeter of a small-scale model. Head at cell centers of the larger-scale model can be interpolated to compute head at points on a model perimeter. Simple linear interpolation is proposed for horizontal interpolation of horizontal-flow components. Bilinear interpolation is proposed for horizontal interpolation of head values. The methods of interpolation provided satisfactory boundary conditions in tests using models of hypothetical aquifers.Many small-scale ground water models are too small to incorporate distant aquifer boundaries. If a larger-scale model exists for the area of interest, flow and head values can be specified for boundaries in the smaller-scale model using values from the larger-scale model. Flow components along rows and columns of a large-scale block-centered finite-difference model can be interpolated to compute horizontal flow across any segment of a perimeter of a small-scale model. Head at cell centers of the larger.scale model can be interpolated to compute head at points on a model perimeter. Simple linear interpolation is proposed for horizontal interpolation of horizontal-flow components. Bilinear interpolation is proposed for horizontal interpolation of head values. The methods of interpolation provided satisfactory boundary conditions in tests using models of hypothetical aquifers.

High-resolution, cryogenic, side-entry type specimen stage

DOEpatents

King, Wayne E.; Merkle, Karl L.

1979-01-01

A high-resolution, cryogenic side-entry type specimen stage includes a copper block within which a specimen can be positioned in the electron beam of an electron microscope, one end of the copper block constituting a specimen heat exchanger, means for directing a flow of helium at cryogenic temperature into the heat exchanger, and electrical leads running from the specimen to the exterior of the microscope for four point D.C. electrical resistivity measurements.

Musculoskeletal motion flow fields using hierarchical variable-sized block matching in ultrasonographic video sequences.

PubMed

Revell, J D; Mirmehdi, M; McNally, D S

2004-04-01

We examine tissue deformations using non-invasive dynamic musculoskeletal ultrasonograhy, and quantify its performance on controlled in vitro gold standard (groundtruth) sequences followed by clinical in vivo data. The proposed approach employs a two-dimensional variable-sized block matching algorithm with a hierarchical full search. We extend this process by refining displacements to sub-pixel accuracy. We show by application that this technique yields quantitatively reliable results.

Teko: A block preconditioning capability with concrete example applications in Navier--Stokes and MHD

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

Cyr, Eric C.; Shadid, John N.; Tuminaro, Raymond S.

This study describes the design of Teko, an object-oriented C++ library for implementing advanced block preconditioners. Mathematical design criteria that elucidate the needs of block preconditioning libraries and techniques are explained and shown to motivate the structure of Teko. For instance, a principal design choice was for Teko to strongly reflect the mathematical statement of the preconditioners to reduce development burden and permit focus on the numerics. Additional mechanisms are explained that provide a pathway to developing an optimized production capable block preconditioning capability with Teko. Finally, Teko is demonstrated on fluid flow and magnetohydrodynamics applications. In addition to highlightingmore » the features of the Teko library, these new results illustrate the effectiveness of recent preconditioning developments applied to advanced discretization approaches.« less

Teko: A block preconditioning capability with concrete example applications in Navier--Stokes and MHD

DOE PAGES

Cyr, Eric C.; Shadid, John N.; Tuminaro, Raymond S.

2016-10-27

This study describes the design of Teko, an object-oriented C++ library for implementing advanced block preconditioners. Mathematical design criteria that elucidate the needs of block preconditioning libraries and techniques are explained and shown to motivate the structure of Teko. For instance, a principal design choice was for Teko to strongly reflect the mathematical statement of the preconditioners to reduce development burden and permit focus on the numerics. Additional mechanisms are explained that provide a pathway to developing an optimized production capable block preconditioning capability with Teko. Finally, Teko is demonstrated on fluid flow and magnetohydrodynamics applications. In addition to highlightingmore » the features of the Teko library, these new results illustrate the effectiveness of recent preconditioning developments applied to advanced discretization approaches.« less

Numerical Investigations of Active Flow Control for Low-Pressure Turbine Blades

DTIC Science & Technology

2008-03-01

points were clustered near the wall, in the separated flow region on the suction side of the 7 blade , and in the wake . Table 1 summarizes the block...Perspective view of blade (computational domain was repeated once in spanwise direction), side view of wake , and top down view of wake . Distributions...to the wake region. A second observation is that the wake turbulence appears to be concentrated in "lumps". In analogy to other wake flows, the blade

Variations in synoptic-scale eddy activity during the life cycles of persistent flow anomalies

NASA Technical Reports Server (NTRS)

Dole, Randall M.; Neilley, Peter P.

1991-01-01

The objective of the study was to identify how synoptic-scale eddy activity varies throughout the life cycles of major scale flow anomalies. In particular, composite analyses of various measures of synoptic-scale eddy activity are constructed, with the composites obtained relative to the onset and termination times of cases typically associated with either blocking or abnormally intense zonal flows. The potential mechanisms that are likely to contribute to the observed changes in eddy behavior are discussed.

Navier-Stokes computation of compressible turbulent flows with a second order closure

NASA Technical Reports Server (NTRS)

Dingus, C.; Kollmann, W.

1991-01-01

The objective was the development of a complete second order closure for wall bounded flows, including all components of the dissipation rate tensor and a numerical solution procedure for the resulting system of equations. The main topics discussed are the closure of the pressure correlations and the viscous destruction terms in the dissipation rate equations and the numerical solution scheme based on a block-tridiagonal solver for the nine equations required for the prediction of plane or axisymmetric flows.

Nonequilibrium thermo-chemical calculations using a diagonal implicit scheme

NASA Technical Reports Server (NTRS)

Imlay, Scott T.; Roberts, Donald W.; Soetrisno, Moeljo; Eberhardt, Scott

1991-01-01

A recently developed computer program for hypersonic vehicle flow analysis is described. The program uses a diagonal implicit algorithm to solve the equations of viscous flow for a gas in thermochemical nonequilibrium. The diagonal scheme eliminates the expense of inverting large block matrices that arise when species conservation equations are introduced. The program uses multiple zones of grids patched together and includes radiation wall and rarefied gas boundary conditions. Solutions are presented for hypersonic flows of air and hydrogen air mixtures.

Development of and Clinical Experience with a Simple Device for Performing Intraoperative Fluorescein Fluorescence Cerebral Angiography: Technical Notes.

PubMed

Ichikawa, Tsuyoshi; Suzuki, Kyouichi; Watanabe, Yoichi; Sato, Taku; Sakuma, Jun; Saito, Kiyoshi

2016-01-01

To perform intraoperative fluorescence angiography (FAG) under a microscope without an integrated FAG function with reasonable cost and sufficient quality for evaluation, we made a small and easy to use device for fluorescein FAG (FAG filter). We investigated the practical use of this FAG filter during aneurysm surgery, revascularization surgery, and brain tumor surgery. The FAG filter consists of two types of filters: an excitatory filter and a barrier filter. The excitatory filter excludes all wavelengths except for blue light and the barrier filter passes long waves except for blue light. By adding this FAG filter to a microscope without an integrated FAG function, light from the microscope illuminating the surgical field becomes blue, which is blocked by the barrier filter. We put the FAG filter on the objective lens of the operating microscope correctly and fluorescein sodium was injected intravenously or intra-arterially. Fluorescence (green light) from vessels in the surgical field and the dyed tumor were clearly observed through the microscope and recorded by a memory device. This method was easy and could be performed in a short time (about 10 seconds). Blood flow of small vessels deep in the surgical field could be observed. Blood flow stagnation could be evaluated. However, images from this method were inferior to those obtained by currently commercially available microscopes with an integrated FAG function. In brain tumor surgery, a stained tumor on the brain surface could be observed using this method. FAG could be performed with a microscope without an integrated FAG function easily with only this FAG filter.

Development of and Clinical Experience with a Simple Device for Performing Intraoperative Fluorescein Fluorescence Cerebral Angiography: Technical Notes

PubMed Central

ICHIKAWA, Tsuyoshi; SUZUKI, Kyouichi; WATANABE, Yoichi; SATO, Taku; SAKUMA, Jun; SAITO, Kiyoshi

2016-01-01

To perform intraoperative fluorescence angiography (FAG) under a microscope without an integrated FAG function with reasonable cost and sufficient quality for evaluation, we made a small and easy to use device for fluorescein FAG (FAG filter). We investigated the practical use of this FAG filter during aneurysm surgery, revascularization surgery, and brain tumor surgery. The FAG filter consists of two types of filters: an excitatory filter and a barrier filter. The excitatory filter excludes all wavelengths except for blue light and the barrier filter passes long waves except for blue light. By adding this FAG filter to a microscope without an integrated FAG function, light from the microscope illuminating the surgical field becomes blue, which is blocked by the barrier filter. We put the FAG filter on the objective lens of the operating microscope correctly and fluorescein sodium was injected intravenously or intra-arterially. Fluorescence (green light) from vessels in the surgical field and the dyed tumor were clearly observed through the microscope and recorded by a memory device. This method was easy and could be performed in a short time (about 10 seconds). Blood flow of small vessels deep in the surgical field could be observed. Blood flow stagnation could be evaluated. However, images from this method were inferior to those obtained by currently commercially available microscopes with an integrated FAG function. In brain tumor surgery, a stained tumor on the brain surface could be observed using this method. FAG could be performed with a microscope without an integrated FAG function easily with only this FAG filter. PMID:26597335

Making Sense of Dynamic Systems: How Our Understanding of Stocks and Flows Depends on a Global Perspective

ERIC Educational Resources Information Center

Fischer, Helen; Gonzalez, Cleotilde

2016-01-01

Stocks and flows (SF) are building blocks of dynamic systems: Stocks change through inflows and outflows, such as our bank balance changing with withdrawals and deposits, or atmospheric CO[subscript 2] with absorptions and emissions. However, people make systematic errors when trying to infer the behavior of dynamic systems, termed SF failure,…

A reuse-based framework for the design of analog and mixed-signal ICs

NASA Astrophysics Data System (ADS)

Castro-Lopez, Rafael; Fernandez, Francisco V.; Rodriguez Vazquez, Angel

2005-06-01

Despite the spectacular breakthroughs of the semiconductor industry, the ability to design integrated circuits (ICs) under stringent time-to-market (TTM) requirements is lagging behind integration capacity, so far keeping pace with still valid Moore"s Law. The resulting gap is threatening with slowing down such a phenomenal growth. The design community believes that it is only by means of powerful CAD tools and design methodologies - and, possibly, a design paradigm shift - that this design gap can be bridged. In this sense, reuse-based design is seen as a promising solution, and concepts such as IP Block, Virtual Component, and Design Reuse have become commonplace thanks to the significant advances in the digital arena. Unfortunately, the very nature of analog and mixed-signal (AMS) design has hindered a similar level of consensus and development. This paper presents a framework for the reuse-based design of AMS circuits. The framework is founded on three key elements: (1) a CAD-supported hierarchical design flow that facilitates the incorporation of AMS reusable blocks, reduces the overall design time, and expedites the management of increasing AMS design complexity; (2) a complete, clear definition of the AMS reusable block, structured into three separate facets or views: the behavioral, structural, and layout facets, the two first for top-down electrical synthesis and bottom-up verification, the latter used during bottom-up physical synthesis; (3) the design for reusability set of tools, methods, and guidelines that, relying on intensive parameterization as well as on design knowledge capture and encapsulation, allows to produce fully reusable AMS blocks. A case study and a functional silicon prototype demonstrate the validity of the paper"s proposals.

Inferior vena cava segmentation with parameter propagation and graph cut.

PubMed

Yan, Zixu; Chen, Feng; Wu, Fa; Kong, Dexing

2017-09-01

The inferior vena cava (IVC) is one of the vital veins inside the human body. Accurate segmentation of the IVC from contrast-enhanced CT images is of great importance. This extraction not only helps the physician understand its quantitative features such as blood flow and volume, but also it is helpful during the hepatic preoperative planning. However, manual delineation of the IVC is time-consuming and poorly reproducible. In this paper, we propose a novel method to segment the IVC with minimal user interaction. The proposed method performs the segmentation block by block between user-specified beginning and end masks. At each stage, the proposed method builds the segmentation model based on information from image regional appearances, image boundaries, and a prior shape. The intensity range and the prior shape for this segmentation model are estimated based on the segmentation result from the last block, or from user- specified beginning mask if at first stage. Then, the proposed method minimizes the energy function and generates the segmentation result for current block using graph cut. Finally, a backward tracking step from the end of the IVC is performed if necessary. We have tested our method on 20 clinical datasets and compared our method to three other vessel extraction approaches. The evaluation was performed using three quantitative metrics: the Dice coefficient (Dice), the mean symmetric distance (MSD), and the Hausdorff distance (MaxD). The proposed method has achieved a Dice of [Formula: see text], an MSD of [Formula: see text] mm, and a MaxD of [Formula: see text] mm, respectively, in our experiments. The proposed approach can achieve a sound performance with a relatively low computational cost and a minimal user interaction. The proposed algorithm has high potential to be applied for the clinical applications in the future.

Thermoreversible hydrogels based on triblock copolymers of poly(ethylene glycol) and carboxyl functionalized poly(ε-caprolactone): The effect of carboxyl group substitution on the transition temperature and biocompatibility in plasma.

PubMed

Safaei Nikouei, Nazila; Vakili, Mohammad Reza; Bahniuk, Markian S; Unsworth, Larry; Akbari, Ali; Wu, Jianping; Lavasanifar, Afsaneh

2015-01-01

In this study we report on the development, characterization and plasma protein interaction of novel thermoresponsive in situ hydrogels based on triblock copolymers of poly(ethylene glycol) (PEG) and poly(α-carboxyl-co-benzyl carboxylate)-ε-caprolactone (PCBCL) having two different degrees of carboxyl group substitution on the PCBCL block. Block copolymers were synthesized through ring-opening polymerization of α-benzyl carboxylate-ε-caprolactone by dihydroxy PEG, leading to the production of poly(α-benzyl carboxylate-ε-caprolactone)-PEG-poly(α-benzyl carboxylate-ε-caprolactone) (PBCL-PEG-PBCL). This was followed by partial debenzylation of PBCL blocks under controlled conditions, leading to the preparation of PCBCL-PEG-PCBCL triblock copolymers with 30 and 54mol.% carboxyl group substitution. Prepared PCBCL-PEG-PCBCL block copolymers have been shown to have a concentration-dependent sol to gel transition as a result of an increase in temperature above ∼29°C, as evidenced by the inverse flow method, differential scanning calorimetry and dynamic mechanical analysis. The sol-gel transition temperature/concentration and dynamic mechanical properties of the gel were found to be dependent on the level of carboxyl group substitution. Both hydrogels (30 and 54mol.% carboxyl group substitution) showed similar amounts of protein adsorption but striking differences in the profiles of the adsorbed proteome. Additionally, the two systems showed similarities in their clot formation kinetics but substantial differences in clot endpoints. The results show great promise for the above-mentioned thermoreversible in situ hydrogels as biocompatible materials for biomedical applications. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Assessment of new biocompatible poly(N-(morpholino)ethyl methacrylate)-based copolymers by transfection of immortalized keratinocytes.

PubMed

Van Overstraeten-Schlögel, Nancy; Shim, Yong-Ho; Tevel, Virginie; Piel, Géraldine; Piette, Jacques; Dubois, Philippe; Raes, Martine

2012-02-01

Skin carcinomas are among the most commonly diagnosed tumors in the world. In this study, we investigated the transfection of immortalized keratinocytes, used as an in vitro model for skin carcinoma, using the antisense technology and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA)-based copolymers. In order to improve the transfection efficiency of the classic PDMAEMA polymers, copolymers were synthesized including a poly(N-morpholino)ethylmethacrylate) (PMEMA) moiety for an improved proton-sponge effect, intended to favour the release of the oligonucleotide from the acidic endosome. These copolymers were synthesized either statistically (with alternating PDMAEMA and PMEMA fragments) or in blocks (one PDMAEMA block followed by one PMEMA block). MTT assays were performed using the PDMAEMA-PMEMA copolymers and revealed no significant cytotoxicity of these polymers at an N/P ratio of 7.3. Using fluorescent oligonucleotides and analyzing transfection efficiency by flow cytometry, we noticed no significant differences between the two kinds of copolymers. However copolymers with a higher DMAEMA content and a higher Mn were also those displaying the highest vectorization efficiency. Confocal microscopy showed that these copolymers induced a fine granular distribution of the transfected antisense oligonucleotides inside the cells. We also assessed the functionality of the transfected antisense oligonucleotide by transfecting immortalized GFP expressing keratinocytes with a GFP antisense oligonucleotide using these copolymers. A significant silencing was achieved with a PDMAEMA-PMEMA in block copolymer (Mn=41,000, 89 % PDMAEMA). Together, these results suggest that PDMAEMA-PMEMA copolymers combining low toxicity, vectorization and proton sponge properties, can be efficiently used to transfect immortalized keratinocytes and so open new perspectives in the therapy of skin carcinomas as well as of other skin diseases of genetic or immunological origin. © 2012 Informa Healthcare USA, Inc.

Enhanced photothermal therapy of biomimetic polypyrrole nanoparticles through improving blood flow perfusion.

PubMed

Wang, Xuejun; Li, Haichun; Liu, Xianping; Tian, Ye; Guo, Huishu; Jiang, Ting; Luo, Zimiao; Jin, Kai; Kuai, Xinping; Liu, Yao; Pang, Zhiqing; Yang, Wuli; Shen, Shun

2017-10-01

In this study, we reported a strategy to improve delivery efficiency of a long-circulation biomimetic photothermal nanoagent for enhanced photothermal therapy through selectively dilating tumor vasculature. By using a simply nanocoating technology, a biomimetic layer of natural red blood cell (RBC) membranes was camouflaged on the surface of photothermal polypyrrole nanoparticles (PPy@RBC NPs). The erythrocyte-mimicking PPy NPs inherited the immune evasion ability from natural RBC resulting in superior prolonged blood retention time. Additionally, excellent photothermal and photoacoustic imaging functionalities were all retained attributing to PPy NPs cores. To further improve the photothermal outcome, the endothelin A (ET A ) receptor antagonist BQ123 was jointly employed to regulate tumor microenvironment. The BQ123 could induce tumor vascular relaxation and increase blood flow perfusion through modulating an ET-1/ET A transduction pathway and blocking the ET A receptor, whereas the vessel perfusion of normal tissues was not altered. Through our well-designed tactic, the concentration of biomimetic PPy NPs in tumor site was significantly improved when administered systematically. The study documented that the antitumor efficiency of biomimetic PPy NPs combined with specific antagonist BQ123 was particularly prominent and was superior to biomimetic PPy NPs (P < 0.05) and PEGylated PPy NPs with BQ123 (P < 0.01), showing that the greatly enhanced photothermal treatment could be achieved with low-dose administration of photothermal agents. Our findings would provide a promising procedure for other similar enhanced photothermal treatment by blocking ET A receptor to dramatically increase the delivery of biomimetic photothermal nanomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oxidized LDL activates blood platelets through CD36/NOX2–mediated inhibition of the cGMP/protein kinase G signaling cascade

PubMed Central

Magwenzi, Simbarashe; Woodward, Casey; Wraith, Katie S.; Aburima, Ahmed; Raslan, Zaher; Jones, Huw; McNeil, Catriona; Wheatcroft, Stephen; Yuldasheva, Nadira; Febbriao, Maria; Kearney, Mark

2015-01-01

Oxidized low-density lipoprotein (oxLDL) promotes unregulated platelet activation in dyslipidemic disorders. Although oxLDL stimulates activatory signaling, it is unclear how these events drive accelerated thrombosis. Here, we describe a mechanism for oxLDL-mediated platelet hyperactivity that requires generation of reactive oxygen species (ROS). Under arterial flow, oxLDL triggered sustained generation of platelet intracellular ROS, which was blocked by CD36 inhibitors, mimicked by CD36-specific oxidized phospholipids, and ablated in CD36−/− murine platelets. oxLDL-induced ROS generation was blocked by the reduced NAD phosphate oxidase 2 (NOX2) inhibitor, gp91ds-tat, and absent in NOX2−/− mice. The synthesis of ROS by oxLDL/CD36 required Src-family kinases and protein kinase C (PKC)-dependent phosphorylation and activation of NOX2. In functional assays, oxLDL abolished guanosine 3′,5′-cyclic monophosphate (cGMP)-mediated signaling and inhibited platelet aggregation and arrest under flow. This was prevented by either pharmacologic inhibition of NOX2 in human platelets or genetic ablation of NOX2 in murine platelets. Platelets from hyperlipidemic mice were also found to have a diminished sensitivity to cGMP when tested ex vivo, a phenotype that was corrected by infusion of gp91ds-tat into the mice. This study demonstrates that oxLDL and hyperlipidemia stimulate the generation of NOX2-derived ROS through a CD36-PKC pathway and may promote platelet hyperactivity through modulation of cGMP signaling. PMID:25710879

Evolutionary Concepts for Decentralized Air Traffic Flow Management

NASA Technical Reports Server (NTRS)

Adams, Milton; Kolitz, Stephan; Milner, Joseph; Odoni, Amedeo

1997-01-01

Alternative concepts for modifying the policies and procedures under which the air traffic flow management system operates are described, and an approach to the evaluation of those concepts is discussed. Here, air traffic flow management includes all activities related to the management of the flow of aircraft and related system resources from 'block to block.' The alternative concepts represent stages in the evolution from the current system, in which air traffic management decision making is largely centralized within the FAA, to a more decentralized approach wherein the airlines and other airspace users collaborate in air traffic management decision making with the FAA. The emphasis in the discussion is on a viable medium-term partially decentralized scenario representing a phase of this evolution that is consistent with the decision-making approaches embodied in proposed Free Flight concepts for air traffic management. System-level metrics for analyzing and evaluating the various alternatives are defined, and a simulation testbed developed to generate values for those metrics is described. The fundamental issue of modeling airline behavior in decentralized environments is also raised, and an example of such a model, which deals with the preservation of flight bank integrity in hub airports, is presented.

Nitric oxide production by cultured human aortic smooth muscle cells: stimulation by fluid flow

NASA Technical Reports Server (NTRS)

Papadaki, M.; Tilton, R. G.; Eskin, S. G.; McIntire, L. V.

1998-01-01

This study demonstrated that exposure of cultured human aortic smooth muscle cells (SMC) to fluid flow resulted in nitric oxide (NO) production, monitored by nitrite and guanosine 3',5'-cyclic monophosphate production. A rapid burst in nitrite production rate was followed by a more gradual increase throughout the period of flow exposure. Neither the initial burst nor the prolonged nitrite production was dependent on the level of shear stress in the range of 1.1-25 dyn/cm2. Repeated exposure to shear stress after a 30-min static period restimulated nitrite production similar to the initial burst. Ca(2+)-calmodulin antagonists blocked the initial burst in nitrite release. An inhibitor of nitric oxide synthase (NOS) blocked nitrite production, indicating that changes in nitrite reflect NO production. Treatment with dexamethasone or cycloheximide had no effect on nitrite production. Monoclonal antibodies directed against the inducible and endothelial NOS isoforms showed no immunoreactivity on Western blots, whereas monoclonal antibodies directed against the neuronal NOS gave specific products. These findings suggest that human aortic SMC express a constitutive neuronal NOS isoform, the enzymatic activity of which is modulated by flow.

Controlling autonomous underwater floating platforms using bacterial fermentation.

PubMed

Biffinger, Justin C; Fitzgerald, Lisa A; Howard, Erinn C; Petersen, Emily R; Fulmer, Preston A; Wu, Peter K; Ringeisen, Bradley R

2013-01-01

Biogenic gas has a wide range of energy applications from being used as a source for crude bio-oil components to direct ignition for heating. The current study describes the use of biogenic gases from Clostridium acetobutylicum for a new application-renewable ballast regeneration for autonomous underwater devices. Uninterrupted (continuous) and blocked flow (pressurization) experiments were performed to determine the overall biogas composition and total volume generated from a semirigid gelatinous matrix. For stopped flow experiments, C. acetobutylicum generated a maximum pressure of 55 psi over 48 h composed of 60 % hydrogen gas when inoculated in a 5 % agar (w/v) support with 5 % glucose (w/v) in the matrix. Typical pressures over 24 h at 318 K ranged from 10 to 33 psi. These blocked flow experiments show for the first time the use of microbial gas production as a way to repressurize gas cylinders. Continuous flow experiments successfully demonstrated how to deliver biogas to an open ballast control configuration for deployable underwater platforms. This study is a starting point for engineering and microbiology investigations of biogas which will advance the integration of biology within autonomous systems.

DNA-Templated Polymerization of Side-Chain-Functionalized Peptide Nucleic Acid Aldehydes

PubMed Central

Kleiner, Ralph E.; Brudno, Yevgeny; Birnbaum, Michael E.; Liu, David R.

2009-01-01

The DNA-templated polymerization of synthetic building blocks provides a potential route to the laboratory evolution of sequence-defined polymers with structures and properties not necessarily limited to those of natural biopolymers. We previously reported the efficient and sequence-specific DNA-templated polymerization of peptide nucleic acid (PNA) aldehydes. Here, we report the enzyme-free, DNA-templated polymerization of side-chain-functionalized PNA tetramer and pentamer aldehydes. We observed that the polymerization of tetramer and pentamer PNA building blocks with a single lysine-based side chain at various positions in the building block could proceed efficiently and sequence-specifically. In addition, DNA-templated polymerization also proceeded efficiently and in a sequence-specific manner with pentamer PNA aldehydes containing two or three lysine side chains in a single building block to generate more densely functionalized polymers. To further our understanding of side-chain compatibility and expand the capabilities of this system, we also examined the polymerization efficiencies of 20 pentamer building blocks each containing one of five different side-chain groups and four different side-chain regio- and stereochemistries. Polymerization reactions were efficient for all five different side-chain groups and for three of the four combinations of side-chain regio- and stereochemistries. Differences in the efficiency and initial rate of polymerization correlate with the apparent melting temperature of each building block, which is dependent on side-chain regio- and stereochemistry, but relatively insensitive to side-chain structure among the substrates tested. Our findings represent a significant step towards the evolution of sequence-defined synthetic polymers and also demonstrate that enzyme-free nucleic acid-templated polymerization can occur efficiently using substrates with a wide range of side-chain structures, functionalization positions within each building block, and functionalization densities. PMID:18341334

Preliminary geologic map of the Murrieta 7.5' quadrangle, Riverside County, California

USGS Publications Warehouse

Kennedy, Michael P.; Morton, Douglas M.

2003-01-01

The Murrieta quadrangle is located in the northern part of the Peninsular Ranges Province and includes parts of two structural blocks, or structural subdivisions of the province. The quadrangle is diagonally crossed by the active Elsinore fault zone, a major fault zone of the San Andreas fault system, and separates the Santa Ana Mountains block to the west from the Perris block to the east. Both blocks are relatively stable internally and within the quadrangle are characterized by the presence of widespread erosional surfaces of low relief. The Santa Ana Mountains block, in the Murrieta quadrangle, is underlain by undifferentiated, thick-layered, granular, impure quartzite and well-layered, fissile, phyllitic metamorphic rock of low metamorphic grade. Both quartzite and phyllitic rocks are Mesozoic. Unconformably overlying the metamorphic rocks are remnants of basalt flows having relatively unmodified flow surfaces. The age of the basalt is about 7-8Ma. Large shallow depressions on the surface of the larger basalt remnants form vernal ponds that contain an endemic flora. Beneath the basalt the upper part of the metamorphic rocks is deeply weathered. The weathering appears to be the same as the regional Paleocene saprolitic weathering in southern California. West of the quadrangle a variable thickness sedimentary rock, physically resembling Paleogene rocks, occurs between the basalt and metamorphic rock. Where not protected by the basalt, the weathered rock has been removed by erosion. The dominant feature on the Perris block in the Murrieta quadrangle is the south half of the Paloma Valley ring complex, part of the composite Peninsular Ranges batholith. The complex is elliptical in plan view and consists of an older ring-dike with two subsidiary short-arced dikes that were emplaced into gabbro by magmatic stoping. Small to large stoped blocks of gabbro are common within the ring-dikes. A younger ring-set of hundreds of thin pegmatite dikes occur largely within the central part of the complex. These pegmatite dikes were emplaced into a domal fracture system, apparently produced by cauldron subsidence, and include in the center of the complex, a number of flat-floored granophyre bodies. The granophyre is interpreted to be the result of pressure quenching of pegmatite magma. Along the eastern edge of the quadrangle is the western part of a large septum of medium metamorphic grade Mesozoic schist. A dissected basalt flow caps the Hogbacks northeast of Temecula, and represents remnants of a channel filling flow. Beneath the basalt is a thin deposit of stream gravel. Having an age of about 10Ma, this basalt is about 2-3Ma older than the basalt flows in the Santa Ana Mountains. The Elsinore fault zone forms a complex of pull-apart basins. The west edge of the fault zone, the Willard Fault, is marked by the high, steep eastern face of the Santa Ana Mountains. The east side of the zone, the Wildomar Fault, forms a less pronounced physiographic step. In the center of the quadrangle a major splay of the fault zone, the Murrieta Hot Springs Fault, strikes east. Branching of the fault zone causes the development of a broad alluvial valley between the Willard Fault and the Murrieta Hot Springs Fault. All but the axial part of the zone between the Willard and Wildomar Faults consist of dissected Pleistocene sedimentary units. The axial part of the zone is underlain by Holocene and latest Pleistocene sedimentary units.

Microfluidic assembly blocks.

PubMed

Rhee, Minsoung; Burns, Mark A

2008-08-01

An assembly approach for microdevice construction using prefabricated microfluidic components is presented. Although microfluidic systems are convenient platforms for biological assays, their use in the life sciences is still limited mainly due to the high-level fabrication expertise required for construction. This approach involves prefabrication of individual microfluidic assembly blocks (MABs) in PDMS that can be readily assembled to form microfluidic systems. Non-expert users can assemble the blocks on glass slides to build their devices in minutes without any fabrication steps. In this paper, we describe the construction and assembly of the devices using the MAB methodology, and demonstrate common microfluidic applications including laminar flow development, valve control, and cell culture.

Enzymatic Continuous Flow Synthesis of Thiol-Terminated Poly(δ-Valerolactone) and Block Copolymers.

PubMed

Zhu, Ning; Huang, Weijun; Hu, Xin; Liu, Yihuan; Fang, Zheng; Guo, Kai

2018-04-01

Thiol-terminated poly(δ-valerolactone) is directly synthesized via enzymatic 6-mercapto-1-hexanol initiated ring-opening polymerization in both batch and microreactor. By using Candida antartica Lipase B immobilized tubular reactor, narrowly dispersed poly(δ-valerolactone) with higher thiol fidelity is more efficiently prepared in contrast to the batch reactor. Moreover, the integrated enzyme packed tubular reactor system is established to perform the chain extension experiments. Thiol-terminated poly(δ-valerolactone)-block-poly(ε-caprolactone) and poly(ε-caprolactone)-block-poly(δ-valerolactone) are easily prepared by modulating the monomer introduction sequence. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of an Innovative Algorithm for Aerodynamics-Structure Interaction Using Lattice Boltzmann Method

NASA Technical Reports Server (NTRS)

Mei, Ren-Wei; Shyy, Wei; Yu, Da-Zhi; Luo, Li-Shi; Rudy, David (Technical Monitor)

2001-01-01

The lattice Boltzmann equation (LBE) is a kinetic formulation which offers an alternative computational method capable of solving fluid dynamics for various systems. Major advantages of the method are owing to the fact that the solution for the particle distribution functions is explicit, easy to implement, and the algorithm is natural to parallelize. In this final report, we summarize the works accomplished in the past three years. Since most works have been published, the technical details can be found in the literature. Brief summary will be provided in this report. In this project, a second-order accurate treatment of boundary condition in the LBE method is developed for a curved boundary and tested successfully in various 2-D and 3-D configurations. To evaluate the aerodynamic force on a body in the context of LBE method, several force evaluation schemes have been investigated. A simple momentum exchange method is shown to give reliable and accurate values for the force on a body in both 2-D and 3-D cases. Various 3-D LBE models have been assessed in terms of efficiency, accuracy, and robustness. In general, accurate 3-D results can be obtained using LBE methods. The 3-D 19-bit model is found to be the best one among the 15-bit, 19-bit, and 27-bit LBE models. To achieve desired grid resolution and to accommodate the far field boundary conditions in aerodynamics computations, a multi-block LBE method is developed by dividing the flow field into various blocks each having constant lattice spacing. Substantial contribution to the LBE method is also made through the development of a new, generalized lattice Boltzmann equation constructed in the moment space in order to improve the computational stability, detailed theoretical analysis on the stability, dispersion, and dissipation characteristics of the LBE method, and computational studies of high Reynolds number flows with singular gradients. Finally, a finite difference-based lattice Boltzmann method is developed for inviscid compressible flows.

Diabetic ketoacidosis

MedlinePlus

... you are sick. If you use an insulin pump, check often to see that insulin is flowing ... is not blocked, kinked or disconnected from the pump. Alternative Names DKA; Ketoacidosis; Diabetes - ketoacidosis Images Food ...

The Simulation Study of Horizontal Axis Water Turbine Using Flow Simulation Solidworks Application

NASA Astrophysics Data System (ADS)

Prasetyo, H.; Budiana, EP; Tjahjana, DDDP; Hadi, S.

2018-02-01

The design of Horizontal Axis Water Turbine in pico hydro power plants involves many parameters. To simplify that, usually using computer simulation is applied. This research performs simulation process variation on turbine blade number, turbine blade curvature angle, turbine bucket angle and blocking system tilt angle. Those four variations were combined in order to obtain the best design of turbine. The study used Flow Simulation Solidworks application, and obtain data on turbine speed, pressure, force, and torque. However, this research focused on turbine torque value. The best design of turbine was obtained in the turbine with 6 blades, blade curvature angle of 65° and bucket angle of 10°, and blocking system tilt angle of 40°. In the best turbine, the produced torque value was 8.464 Nm.

New horizons in orthodontics & dentofacial orthopedics: fixed Twin Blocks & TransForce lingual appliances.

PubMed

Clark, William John

2011-01-01

During the 20th century functional appliances evolved from night time wear to more flexible appliances for increased day time wear to full time wear with Twin Block appliances. The current trend is towards fixed functional appliances and this paper introduces the Fixed Twin Block, bonded to the teeth to eliminate problems of compliance in functional therapy. TransForce lingual appliances are pre-activated and may be used in first phase treatment for sagittal and transverse arch development. Alternatively they may be integrated with fixed appliances at any stage of treatment.

Dendronized Metal Nanoparticles-Self-Organizing Building Blocks for the Design of New Functional Materials

DTIC Science & Technology

2016-04-01

characterization has just started.       The hybrids that we have synthesized are based on plasmonic gold and  silver   nanoparticles  (NPs) but  the concept  is...AFRL-AFOSR-UK-TR-2016-0010 Dendronized metal nanoparticles - self-organizing building blocks for the design of new functional materials Bertrand...2015 4. TITLE AND SUBTITLE Dendronized metal nanoparticles - self-organizing building blocks for the design of new functional materials 5a. CONTRACT

Mechanism of orientation of stimulating currents in magnetic brain stimulation (abstract)

NASA Astrophysics Data System (ADS)

Ueno, S.; Matsuda, T.

1991-04-01

We made a functional map of the human motor cortex related to the hand and foot areas by stimulating the human brain with a focused magnetic pulse. We observed that each functional area in the cortex has an optimum direction for which stimulating currents can produce neural excitation. The present report focuses on the mechanism which is responsible for producing this anisotropic response to brain stimulation. We first obtained a functional map of the brain related to the left ADM (abductor digiti minimi muscles). When the stimulating currents were aligned in the direction from the left to the right hemisphere, clear EMG (electromyographic) responses were obtained only from the left ADM to magnetic stimulation of both hemisphere. When the stimulating currents were aligned in the direction from the right to the left hemisphere, clear EMG signals were obtained only from the right ADM to magnetic stimulation of both hemisphere. The functional maps of the brain were sensitive to changes in the direction of the stimulating currents. To explain the phenomena obtained in the experiments, we developed a model of neural excitation elicited by magnetic stimulation. When eddy currents which are induced by pulsed magnetic fields flow in the direction from soma to the distal part of neural fiber, depolarized area in the distal part are excited, and the membrane excitation propagates along the nerve fiber. In contrast, when the induced currents flow in the direction from the distal part to soma, hyperpolarized parts block or inhibit neural excitation even if the depolarized parts near the soma can be excited. The model explains our observation that the orientation of the induced current vectors reflect both the functional and anatomical organization of the neural fibers in the brain.

Flux-split algorithms for flows with non-equilibrium chemistry and vibrational relaxation

NASA Technical Reports Server (NTRS)

Grossman, B.; Cinnella, P.

1990-01-01

The present consideration of numerical computation methods for gas flows with nonequilibrium chemistry thermodynamics gives attention to an equilibrium model, a general nonequilibrium model, and a simplified model based on vibrational relaxation. Flux-splitting procedures are developed for the fully-coupled inviscid equations encompassing fluid dynamics and both chemical and internal energy-relaxation processes. A fully coupled and implicit large-block structure is presented which embodies novel forms of flux-vector split and flux-difference split algorithms valid for nonequilibrium flow; illustrative high-temperature shock tube and nozzle flow examples are given.

Rotating stall simulation for axial and centrifugal compressors

NASA Astrophysics Data System (ADS)

Halawa, Taher; Gadala, Mohamed S.

2017-05-01

This study presents a numerical simulation of the rotating stall phenomenon in axial and centrifugal compressors with detailed descriptions of stall precursors and its development with time. Results showed that the vaneless region of the centrifugal compressor is the most critical location affected by stall. It was found that the tip leakage flow and the back flow impingement are the main cause of the stall development at the impeller exit area for centrifugal compressors. The results of the axial compressor simulations indicated that the early separated flow combined with the tip leakage flow can block the impeller passages during stall.

3 CFR - Delegation of Certain Functions and Authority Under Section 5(a) of the Tom Lantos Block Burmese...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 3 The President 1 2013-01-01 2013-01-01 false Delegation of Certain Functions and Authority Under Section 5(a) of the Tom Lantos Block Burmese Junta's Anti-Democratic Efforts Act of 2008 Presidential Documents Other Presidential Documents Memorandum of August 29, 2012 Delegation of Certain Functions and...

Preparation and development of block copolypeptide vesicles and hydrogels for biological and medical applications.

PubMed

Deming, Timothy J

2014-01-01

There have been many recent advances in the controlled polymerization of α-amino acid-N-carboxyanhydride (NCA) monomers into well-defined block copolypeptides. Transition metal initiating systems allow block copolypeptide synthesis with excellent control over number and lengths of block segments, chain length distribution, and chain-end functionality. Using this and other methods, block copolypeptides of controlled dimensions have been prepared and their self-assembly into organized structures studied by many research groups. The ability of well-defined block copolypeptides to assemble into supramolecular copolypeptide vesicles and hydrogels has led to the development of these materials for use in biological and medical applications. These assemblies have been found to possess unique properties that are derived from the amino acid building blocks and ordered conformations of the polypeptide segments. Recent work on the incorporation of active and stimulus-responsive functionality in these materials has tremendously increased their potential for use in biological and medical studies. © 2014 Wiley Periodicals, Inc.

Abdominal sounds

MedlinePlus

... intestines, or strangulation of the bowel and death ( necrosis ) of the bowel tissue. Very high-pitched bowel ... missing bowel sounds may be caused by: Blocked blood vessels prevent the intestines from getting proper blood flow. ...

The nonlinear response in a baroclinic model to stationary forcings

NASA Technical Reports Server (NTRS)

Roads, J. O.

1982-01-01

Wave-zonal-flow interaction studies demonstrated that stratospheric warnings and blocking may be described by the same basic mechanisms although different results occurred for different horizontal scales.

Atrial myxoma

MedlinePlus

... Pieces of the tumor can move to the brain, eye, or limbs. If the tumor grows inside the heart, it can block blood flow. This may require emergency ... myxoma References Lenihan DJ, Yusuf SW. Tumors ...

From spinning conformal blocks to matrix Calogero-Sutherland models

NASA Astrophysics Data System (ADS)

Schomerus, Volker; Sobko, Evgeny

2018-04-01

In this paper we develop further the relation between conformal four-point blocks involving external spinning fields and Calogero-Sutherland quantum mechanics with matrix-valued potentials. To this end, the analysis of [1] is extended to arbitrary dimensions and to the case of boundary two-point functions. In particular, we construct the potential for any set of external tensor fields. Some of the resulting Schrödinger equations are mapped explicitly to the known Casimir equations for 4-dimensional seed conformal blocks. Our approach furnishes solutions of Casimir equations for external fields of arbitrary spin and dimension in terms of functions on the conformal group. This allows us to reinterpret standard operations on conformal blocks in terms of group-theoretic objects. In particular, we shall discuss the relation between the construction of spinning blocks in any dimension through differential operators acting on seed blocks and the action of left/right invariant vector fields on the conformal group.

Vertical and lateral fluid flow related to a large growth fault, South Eugene Island Block 330 field, offshore Louisiana

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

Losh, S.; Eglinton, L.; Schoell, M.

1999-02-01

Data from sediments in and near a large growth fault adjacent to the giant South Eugene Island Block 330 field, offshore Louisiana, indicate that the fault has acted as a conduit for fluids whose flux has varied in space and time. Core and cuttings samples from two wells that penetrated the same fault about 300 m apart show markedly different thermal histories and evidence for mass flux. Sediments within and adjacent to the fault zone in the US Department of Energy-Pennzoil Pathfinder well at about 2200 m SSTVD (subsea true vertical depth) showed little paleothermal or geochemical evidence for through-goingmore » fluid flow. The sediments were characterized by low vitrinite reflectances (R{sub {omicron}}), averaging 0.3% R{sub {omicron}}, moderate to high {delta}{sup 18}O and {delta}{sup 13}C values, and little difference in major or trace element composition between deformed and undeformed sediments. In contrast, faulted sediments from the A6ST well, which intersects the A fault at 1993 m SSTVD, show evidence for a paleothermal anomaly (0.55% R{sub {omicron}}) and depleted {delta}{sup 18}O and {delta}{sup 13}C values. Overall, indicators of mass and heat flux indicate the main growth fault zone in South Eugene Island Block 330 has acted as a conduit for ascending fluids, although the cumulative fluxes vary along strike. This conclusion is corroborated by oil and gas distribution in downthrown sands in Blocks 330 and 331, which identify the fault system in northwestern Block 330 as a major feeder.« less

Rigorous assessment of patterning solution of metal layer in 7 nm technology node

NASA Astrophysics Data System (ADS)

Gao, Weimin; Ciofi, Ivan; Saad, Yves; Matagne, Philippe; Bachmann, Michael; Gillijns, Werner; Lucas, Kevin; Demmerle, Wolfgang; Schmoeller, Thomas

2016-01-01

In a 7 nm node (N7), the logic design requires a critical poly pitch of 42 to 45 nm and a metal 1 (M1) pitch of 28 to 32 nm. Such high-pattern density pushes the 193 immersion lithography solution toward its limit and also brings extremely complex patterning scenarios. The N7 M1 layer may require a self-aligned quadruple patterning (SAQP) with a triple litho-etch (LE3) block process. Therefore, the whole patterning process flow requires multiple exposure+etch+deposition processes and each step introduces a particular impact on the pattern profiles and the topography. In this study, we have successfully integrated a simulation tool that enables emulation of the whole patterning flow with realistic process-dependent three-dimensional (3-D) profile and topology. We use this tool to study the patterning process variations of the N7 M1 layer including the overlay control, the critical dimension uniformity budget, and the lithographic process window (PW). The resulting 3-D pattern structure can be used to optimize the process flow, verify design rules, extract parasitics, and most importantly, simulate the electric field, and identify hot spots for dielectric reliability. As an example application, the maximum electric field at M1 tip-to-tip, which is one of the most critical patterning locations, has been simulated and extracted. The approach helps to investigate the impact of process variations on dielectric reliability. We have also assessed the alternative M1 patterning flow with a single exposure block using extreme ultraviolet lithography (EUVL) and analyzed its advantages compared to the LE3 block approach.

The relationship between functional sciatic nerve block duration and the rate of release of lidocaine from a controlled-release matrix.

PubMed

Gerner, Peter; Wang, Chi-Fei; Lee, Byung-Sang; Suzuki, Suzuko; Degirolami, Umberto; Gandhi, Ankur; Knaack, David; Strichartz, Gary

2010-07-01

Nerve blocks of long duration are often desirable in perioperative and postoperative situations. The relationship between the duration of such blocks and the rate at which a local anesthetic is released is important to know for developing a localized drug delivery system that will optimize block duration. Lidocaine concentration was varied in 1 series of formulations (OSB-L) containing a constant amount of release rate modifier. In another series (OST-R), the release rate modifier was varied while the lidocaine content was held constant. Release kinetics were measured in vitro and correlated to the in vivo duration of antinociceptive and motor block effects when the formulation was implanted next to the rat sciatic nerve. In parallel studies, rats receiving different formulations of slow-release lidocaine were fixed by intracardiac perfusion with 4% paraformaldehyde and nerve-muscle tissue taken for histopathological analysis. In this study, we have demonstrated that the most important variable for effecting functional nerve block, i.e., the blockade of impulses in the relevant fibers of the sciatic nerve, is the rate of lidocaine release at that time. For the OSB-L formulations (lidocaine concentrations of 1.875%, 3.75%, 7.5%, and 15% at a constant release rate modifier of 5%), the average in vitro release rates at 50% recovery of motor block and nociceptive block were 0.91 +/- 0.28 and 1.75 +/- 0.61 mg/h, respectively. For the OST-R formulations (16% lidocaine with release rate modifier concentrations of 1.875%, 3.75%, 7.5%, and 15%), the average in vitro release rates at 50% recovery of motor block and nociceptive block were 2.33 +/- 1.39 and 4.34 +/- 1.09 mg/h, respectively. The OSB-L formulations showed a dose-dependent increase in block duration proportional to an increase in initial lidocaine concentration, whereas the OST-R formulations showed a nonmonotonic relationship between release rate modifier concentration and block duration. The histopathological studies at 24 hours, 3, 5, or 7 days, and 4 weeks after the implantation revealed inflammatory reactions with degrees correlated with lidocaine content, but limited to the connective tissue and muscle immediately surrounding the implanted material. Despite these observed inflammatory reactions, nociceptive and motor block function returned to normal, preimplantation values in all animals. Increasing initial lidocaine content proportionately increased the duration of functional sciatic nerve block. However, decreasing the release rate per se does not give a proportional increase in block duration. Instead, there seems to be an optimal, intermediate release rate for achieving the maximum duration of block.

Impact of hydrotherapy on skin blood flow: How much is due to moisture and how much is due to heat?

PubMed

Petrofsky, Jerrold; Gunda, Shashi; Raju, Chinna; Bains, Gurinder S; Bogseth, Michael C; Focil, Nicholas; Sirichotiratana, Melissa; Hashemi, Vahideh; Vallabhaneni, Pratima; Kim, Yumi; Madani, Piyush; Coords, Heather; McClurg, Maureen; Lohman, Everett

2010-02-01

Hydrotherapy and whirlpool are used to increase skin blood flow and warm tissue. However, recent evidence seems to show that part of the increase in skin blood flow is not due to the warmth itself but due to the moisture content of the heat. Therefore, two series of experiments were accomplished on 10 subjects with an average age of 24.2 +/- 9.7 years and free of diabetes and cardiovascular disease. Subjects sat in a 37 degrees C hydrotherapy pool under two conditions: one in which a thin membrane protecting their skin from moisture while their arm was submerged in water and the second where their arm was allowed to be exposed to the water for 15 minutes. During this period of time, skin and body temperature were measured as well as skin blood flow by a Laser Doppler Imager. The results of the experiments showed that the vapor barrier blocked any change in skin moisture content during submersion in water, and while skin temperature was the same as during exposure to the water, the blood flow with the arm exposed to water increased from 101.1 +/- 10.4 flux to 224.9 +/- 18.2 flux, whereas blood flow increased to only 118.7 +/- 11.4 flux if the moisture of the water was blocked. Thus, a substantial portion of the increase in skin blood flow associated with warm water therapy is probably associated with moisturizing of the skin rather than the heat itself.

Nonintrusive Flow Rate Determination Through Space Shuttle Water Coolant Loop Floodlight Coldplate

NASA Technical Reports Server (NTRS)

Werlink, Rudolph; Johnson, Harry; Margasahayam, Ravi

1997-01-01

Using a Nonintrusive Flow Measurement System (NFMS), the flow rates through the Space Shuttle water coolant coldplate were determined. The objective of this in situ flow measurement was to prove or disprove a potential block inside the affected coldplate had contributed to a reduced flow rate and the subsequent ice formation on the Space Shuttle Discovery. Flow through the coldplate was originally calculated to be 35 to 38 pounds per hour. This application of ultrasonic technology advanced the envelope of flow measurements through use of 1/4-inch-diameter tubing, which resulted in extremely low flow velocities (5 to 30 pounds per hour). In situ measurements on the orbiters Discovery and Atlantis indicated both vehicles, on the average, experienced similar flow rates through the coldplate (around 25 pounds per hour), but lower rates than the designed flow. Based on the noninvasive checks, further invasive troubleshooting was eliminated. Permanent monitoring using the NFMS was recommended.

Block clustering based on difference of convex functions (DC) programming and DC algorithms.

PubMed

Le, Hoai Minh; Le Thi, Hoai An; Dinh, Tao Pham; Huynh, Van Ngai

2013-10-01

We investigate difference of convex functions (DC) programming and the DC algorithm (DCA) to solve the block clustering problem in the continuous framework, which traditionally requires solving a hard combinatorial optimization problem. DC reformulation techniques and exact penalty in DC programming are developed to build an appropriate equivalent DC program of the block clustering problem. They lead to an elegant and explicit DCA scheme for the resulting DC program. Computational experiments show the robustness and efficiency of the proposed algorithm and its superiority over standard algorithms such as two-mode K-means, two-mode fuzzy clustering, and block classification EM.

Additive Manufacturing of Molds for Fabrication of Insulated Concrete Block

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

Love, Lonnie J.; Lloyd, Peter D.

ORNL worked with concrete block manufacturer, NRG Insulated Block, to demonstrate additive manufacturing of a multi-component block mold for its line of insulated blocks. Solid models of the mold parts were constructed from existing two-dimensional drawings and the parts were fabricated on a Stratasys Fortus 900 using ULTEM 9085. Block mold parts were delivered to NRG and installed on one of their fabrication lines. While form and fit were acceptable, the molds failed to function during NRG’s testing.

Photoconductivity enhancement and charge transport properties in ruthenium-containing block copolymer/carbon nanotube hybrids.

PubMed

Lo, Kin Cheung; Hau, King In; Chan, Wai Kin

2018-04-05

Functional polymer/carbon nanotube (CNT) hybrid materials can serve as a good model for light harvesting systems based on CNTs. This paper presents the synthesis of block copolymer/CNT hybrids and the characterization of their photocurrent responses by both experimental and computational approaches. A series of functional diblock copolymers was synthesized by reversible addition-fragmentation chain transfer polymerizations for the dispersion and functionalization of CNTs. The block copolymers contain photosensitizing ruthenium complexes and modified pyrene-based anchoring units. The photocurrent responses of the polymer/CNT hybrids were measured by photoconductive atomic force microscopy (PCAFM), from which the experimental data were analyzed by vigorous statistical models. The difference in photocurrent response among different hybrids was correlated to the conformations of the hybrids, which were elucidated by molecular dynamics simulations, and the electronic properties of polymers. The photoresponse of the block copolymer/CNT hybrids can be enhanced by introducing an electron-accepting block between the photosensitizing block and the CNT. We have demonstrated that the application of a rigorous statistical methodology can unravel the charge transport properties of these hybrid materials and provide general guidelines for the design of molecular light harvesting systems.

Enhanced Line Integral Convolution with Flow Feature Detection

NASA Technical Reports Server (NTRS)

Lane, David; Okada, Arthur

1996-01-01

The Line Integral Convolution (LIC) method, which blurs white noise textures along a vector field, is an effective way to visualize overall flow patterns in a 2D domain. The method produces a flow texture image based on the input velocity field defined in the domain. Because of the nature of the algorithm, the texture image tends to be blurry. This sometimes makes it difficult to identify boundaries where flow separation and reattachments occur. We present techniques to enhance LIC texture images and use colored texture images to highlight flow separation and reattachment boundaries. Our techniques have been applied to several flow fields defined in 3D curvilinear multi-block grids and scientists have found the results to be very useful.

Asymmetrical flow field-flow fractionation with multi-angle light scattering and quasi-elastic light scattering for characterization of polymersomes: comparison with classical techniques.

PubMed

Till, Ugo; Gaucher-Delmas, Mireille; Saint-Aguet, Pascale; Hamon, Glenn; Marty, Jean-Daniel; Chassenieux, Christophe; Payré, Bruno; Goudounèche, Dominique; Mingotaud, Anne-Françoise; Violleau, Frédéric

2014-12-01

Polymersomes formed from amphiphilic block copolymers, such as poly(ethyleneoxide-b-ε-caprolactone) (PEO-b-PCL) or poly(ethyleneoxide-b-methylmethacrylate), were characterized by asymmetrical flow field-flow fractionation coupled with quasi-elastic light scattering (QELS), multi-angle light scattering (MALS), and refractive index detection, leading to the determination of their size, shape, and molecular weight. The method was cross-examined with more classical ones, like batch dynamic and static light scattering, electron microscopy, and atomic force microscopy. The results show good complementarities between all the techniques; asymmetrical flow field-flow fractionation being the most pertinent one when the sample exhibits several different types of population.

ETARA - EVENT TIME AVAILABILITY, RELIABILITY ANALYSIS

NASA Technical Reports Server (NTRS)

Viterna, L. A.

1994-01-01

The ETARA system was written to evaluate the performance of the Space Station Freedom Electrical Power System, but the methodology and software can be modified to simulate any system that can be represented by a block diagram. ETARA is an interactive, menu-driven reliability, availability, and maintainability (RAM) simulation program. Given a Reliability Block Diagram representation of a system, the program simulates the behavior of the system over a specified period of time using Monte Carlo methods to generate block failure and repair times as a function of exponential and/or Weibull distributions. ETARA can calculate availability parameters such as equivalent availability, state availability (percentage of time at a particular output state capability), continuous state duration and number of state occurrences. The program can simulate initial spares allotment and spares replenishment for a resupply cycle. The number of block failures are tabulated both individually and by block type. ETARA also records total downtime, repair time, and time waiting for spares. Maintenance man-hours per year and system reliability, with or without repair, at or above a particular output capability can also be calculated. The key to using ETARA is the development of a reliability or availability block diagram. The block diagram is a logical graphical illustration depicting the block configuration necessary for a function to be successfully accomplished. Each block can represent a component, a subsystem, or a system. The function attributed to each block is considered for modeling purposes to be either available or unavailable; there are no degraded modes of block performance. A block does not have to represent physically connected hardware in the actual system to be connected in the block diagram. The block needs only to have a role in contributing to an available system function. ETARA can model the RAM characteristics of systems represented by multilayered, nesting block diagrams. There are no restrictions on the number of total blocks or on the number of blocks in a series, parallel, or M-of-N parallel subsystem. In addition, the same block can appear in more than one subsystem if such an arrangement is necessary for an accurate model. ETARA 3.3 is written in APL2 for IBM PC series computers or compatibles running MS-DOS and the APL2 interpreter. Hardware requirements for the APL2 system include 640K of RAM, 2Mb of extended memory, and an 80386 or 80486 processor with an 80x87 math co-processor. The standard distribution medium for this package is a set of two 5.25 inch 360K MS-DOS format diskettes. A sample executable is included. The executable contains licensed material from the APL2 for the IBM PC product which is program property of IBM; Copyright IBM Corporation 1988 - All rights reserved. It is distributed with IBM's permission. The contents of the diskettes are compressed using the PKWARE archiving tools. The utility to unarchive the files, PKUNZIP.EXE, is included. ETARA was developed in 1990 and last updated in 1991.

Solution processed ternary blend nano-composite charge regulation layer to enhance inverted OLED performances

NASA Astrophysics Data System (ADS)

Kaçar, Rifat; Mucur, Selin Pıravadılı; Yıldız, Fikret; Dabak, Salih; Tekin, Emine

2018-04-01

Inverted bottom-emission organic light emitting diodes (IBOLEDs) have attracted increasing attention due to their exceptional air stability and applications in active-matrix displays. For gaining high IBOLED device efficiencies, it is crucial to develop an effective strategy to make the bottom electrode easy for charge injection and transport. Charge selectivity, blocking the carrier flow towards the unfavourable side, plays an important role in determining charge carrier balance and accordingly radiative recombination efficiency. It is therefore highly desirable to functionalize an interfacial layer which will perform many different tasks simultaneously. Here, we contribute to the hole-blocking ability of the zinc oxide/polyethyleneimine (ZnO:PEI) nano-composite (NC) interlayer with the intention of increasing the OLED device efficiency. With this purpose in mind, a small amount of 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBi) was added as a hole-blocking molecule into the binary blend of ZnO and PEI solution. The device with a ternary ZnO:PEI:TPBi NC interlayer achieved a maximum current efficiency of 38.20 cd A-1 and a power efficiency of 34.29 lm W-1 with a luminance of 123 200 cd m-2, which are high performance parameters for inverted device architecture. The direct comparisons of device performances incorporating ZnO only, ZnO/PEI bilayers, and ZnO:PEI binary NC counterparts were also performed, which shed light on the origin of device performance enhancement.

Role of the urokinase plasminogen activator receptor in mediating impaired efferocytosis of anti-SSA/Ro-bound apoptotic cardiocytes: Implications in the pathogenesis of congenital heart block.

PubMed

Briassouli, Paraskevi; Komissarova, Elena V; Clancy, Robert M; Buyon, Jill P

2010-08-06

Binding of maternal anti-Ro/La antibodies to cognate antigen expressed on apoptotic cardiocytes decreases clearance by healthy cardiocytes, which may contribute to the development of autoimmune associated congenital heart block and fatal cardiomyopathy. Given recent evidence implicating the urokinase plasminogen activator receptor (uPAR) as a "don't eat me" signal during efferocytosis, experiments addressed whether surface bound anti-Ro antibodies inhibit apoptotic cell removal via an effect on the expression/function of the urokinase-type plasminogen activator protease uPA/uPAR system. As assessed by flow cytometry and confocal microscopy, uPAR colocalizes and interacts with Ro60 on the surface of apoptotic human fetal cardiocytes. Blocking of uPAR enhances phagocytosis of apoptotic cardiocytes by healthy cardiocytes and reverses the anti-Ro60-dependent impaired clearance of apoptotic cardiocytes. Binding of anti-Ro60 antibodies to apoptotic cardiocytes results in increased uPAR expression, as well as enhanced uPA activity. The binding of anti-Ro60 did not alter other surface molecules involved in cell recognition (calreticulin, CD31, or CD47). These data suggest that increased uPAR expression and uPA activity induced by anti-Ro60 binding to the apoptotic fetal cardiocyte provide a molecular basis by which these antibodies inhibit efferocytosis and ultimately lead to scar of the fetal conduction system and working myocardium.