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Sample records for bed slope effects

  1. Bed slope effects on turbulent wave boundary layers: 2. Comparison with skewness, asymmetry, and other effects

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Fredsøe, Jørgen; Sumer, B. Mutlu

    2009-01-01

    contributions believed to play a prominent role in cross-shore boundary layer and sediment transport processes: (1) converging-diverging effects from bed slope, (2) wave skewness, (3) wave asymmetry, and (4) waves combined with superposed negative currents (intended to loosely represent, for example, return...... currents or undertow). The effects from each of the four components are isolated and quantified using a standard set of bed shear stress quantities, allowing their easy comparison. For conditions representing large shallow-water waves on steep slopes, the results suggest that converging-diverging effects...... from beach slope may make a significant onshore bed load contribution. Generally, however, the results suggest wave skewness (in addition to conventional steady streaming) as the most important onshore contribution outside the surf zone. Streaming induced within the wave boundary layer is also...

  2. Effects of relative submergence and bed slope on sediment incipient motion under decelerating flows

    Directory of Open Access Journals (Sweden)

    Bolhassani Ramin

    2015-12-01

    Full Text Available This paper presents the results of an experimental study to quantify the effects of bed slope and relative submergence on incipient motion of sediment under decelerating flows. Experiments were conducted in an experimental tilting-flume of 8 m long 0.4 m wide and 0.6 m deep with glass-walls. Three uniform sediments with median grain sizes of 0.95, 1.8 and 3.8 mm and three bed slopes of 0.0075, 0.0125 and 0.015 were used under decelerating flow. The main conclusion is that the Shields diagram, which is commonly used to evaluate the critical shear stress, is not suitable to predict the critical shear stress under decelerating flows.

  3. Bed slope effects on turbulent wave boundary layers: 1. Model validation and quantification of rough-turbulent results

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Fredsøe, Jørgen; Sumer, B. Mutlu

    2009-01-01

    streaming is conceptually explained using analogies from steady converging and diffuser flows. A parametric study is undertaken to assess both the peak and time-averaged bed shear stresses in converging and diverging half periods under rough-turbulent conditions. The results are presented as friction factor......A numerical model solving incompressible Reynolds-averaged Navier-Stokes equations, combined with a two-equation k-omega turbulence closure, is used to study converging-diverging effects from a sloping bed on turbulent (oscillatory) wave boundary layers. Bed shear stresses from the numerical model...... diagrams. A local similarity condition is derived for relating oscillatory flow in a convergent-divergent tunnel, as considered herein, to shoaling shallow-water waves by matching spatial gradients in the free stream orbital length....

  4. Full-wave algorithm to model effects of bedding slopes on the response of subsurface electromagnetic geophysical sensors near unconformities

    Science.gov (United States)

    Sainath, Kamalesh; Teixeira, Fernando L.

    2016-05-01

    We propose a full-wave pseudo-analytical numerical electromagnetic (EM) algorithm to model subsurface induction sensors, traversing planar-layered geological formations of arbitrary EM material anisotropy and loss, which are used, for example, in the exploration of hydrocarbon reserves. Unlike past pseudo-analytical planar-layered modeling algorithms that impose parallelism between the formation's bed junctions, our method involves judicious employment of Transformation Optics techniques to address challenges related to modeling relative slope (i.e., tilting) between said junctions (including arbitrary azimuth orientation of each junction). The algorithm exhibits this flexibility, both with respect to loss and anisotropy in the formation layers as well as junction tilting, via employing special planar slabs that coat each "flattened" (i.e., originally tilted) planar interface, locally redirecting the incident wave within the coating slabs to cause wave fronts to interact with the flattened interfaces as if they were still tilted with a specific, user-defined orientation. Moreover, since the coating layers are homogeneous rather than exhibiting continuous material variation, a minimal number of these layers must be inserted and hence reduces added simulation time and computational expense. As said coating layers are not reflectionless however, they do induce artificial field scattering that corrupts legitimate field signatures due to the (effective) interface tilting. Numerical results, for two half-spaces separated by a tilted interface, quantify error trends versus effective interface tilting, material properties, transmitter/receiver spacing, sensor position, coating slab thickness, and transmitter and receiver orientation, helping understand the spurious scattering's effect on reliable (effective) tilting this algorithm can model. Under the effective tilting constraints suggested by the results of said error study, we finally exhibit responses of sensors

  5. Full-Wave Algorithm to Model Effects of Bedding Slopes on the Response of Subsurface Electromagnetic Geophysical Sensors near Unconformities

    CERN Document Server

    Sainath, Kamalesh

    2015-01-01

    We propose a full-wave pseudo-analytical numerical electromagnetic (EM) algorithm to model subsurface induction sensors, traversing planar-layered geological formations of arbitrary EM material anisotropy and loss, which are used, for example, in the exploration of hydrocarbon reserves. Unlike past pseudo-analytical planar-layered modeling algorithms that impose parallelism between the formation's bed junctions however, our method involves judicious employment of Transformation Optics techniques to address challenges related to modeling arbitrarily-oriented, relative slope (i.e., tilting) between said junctions. The algorithm exhibits this flexibility, both with respect to anisotropy in the formation layers as well as junction tilting, via employing special planar slabs that coat each "flattened" (i.e., originally tilted) planar interface, locally redirecting the incident wave within the coating slabs to cause wave fronts to interact with the flattened interfaces as if they were still tilted with a specific, ...

  6. Wave interaction with large roughness elements on an impermeable sloping bed

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Christensen, Erik Damgaard; Sumer, B. Mutlu

    2012-01-01

    The present paper presents the results of an experimental and numerical investigation of the flow between large roughness elements on a steep sloping impermeable bed during wave action. The setup is designed to resemble a breakwater structure. The work is part of a study where the focus is on the...... details in the porous core flow and the armour layer flow i.e. the interaction between the two flow domains and the effect on the armour layer stability. In order to isolate the processes involved with the flow in the porous core the investigations are first carried out with a completely impermeable bed...... hereby add more details to the understanding of the fluid-structure interaction....

  7. A Three-Point Method for Separating Incident and Reflected Waves over A Sloping Bed

    Institute of Scientific and Technical Information of China (English)

    CHANG Hsien-Kuo

    2002-01-01

    This study presents a three-point method for separating incident and reflected waves to explain normally incident waves' propagating over a sloping bed. Linear wave shoaling is used to determine changes in wave amplitude and phase in response to variations of bathymetry. The wave reflection coefficient and incident amplitude are estimated from wave heights measured at three fixed wave gauges with unequal spacing. Sensitivity analysis demonstrates that the proposed method can predict the reflection and amplitude of waves over a sloping bed more accurately than the two-point method.

  8. An assessment of biological processes close to the sea bed in a slope region and its significance to the assessment of sea bed disposal of radioactive waste

    International Nuclear Information System (INIS)

    Vertical profiles of planktonic and micronektonic biomass observed close to the sea bed along a transect running up the continental slope on the southern flank of the Porcupine Seabight (to the southwest of Ireland) showed that a doubling in biomass concentration occurs from 100 to 10m above the sea bed. Comparison with biomass concentrations at two deep water stations, one in the Seabight and the other in the Rockall Trough, showed that there was a consistent increase in standing crop close to the sea bed over the slope. Supplementary data were collected on the northern flank of the Seabight. Analysis of both taxonomic groups and individual species showed that some taxa were more abundant near the sea floor and extended their vertical ranges to greater depths over the slope than over deep water, other taxa were unaffected. The implications to the problem of assessing the safety of sea bed disposal of high level radioactive waste are summarised. (author)

  9. Check dams effects on sediment transport in steep slope flume

    Science.gov (United States)

    Piton, Guillaume; Recking, Alain

    2014-05-01

    Depending on many influences (geology, relief, hydrology, land use, etc.) some mountainous watershed are prone to cause casualties and facilities damages. Large amounts of sediments episodically released by torrents are often the biggest problem in torrent related hazard mitigation. Series of transversal structures as check dams and ground sills are often used in the panel of risk mitigation technics. A large literature exits on check dams and it mainly concerns engineering design, e.g. toe scouring, stability stress diagram, changes in upper and lower reaches equilibrium slopes. Check dams in steep slope rivers constitute fixed points in the bed profile and prevent general bed incision. However their influence on sediment transport once they are filled is not yet clear. Two flume test campaigns, synthetize in Table 1, were performed to investigate this question: Table 1 : experiment plan Run (duration) Ref1 (50h)CD1a (30h)CD1b (30h)Ref2 (92h)CD2 (18h) Solid feeding discharge (g.s^-1) 44 44 44 60 60 Number of check dams none 1 3 none 2 A nearly 5-m-long, 10-cm-wide and 12%-steep flume was used. The water discharge was set to 0,55 l/s in all runs. A mixture of poorly sorted natural sediments with diameters between 0.8 and 40 mm was used. An open solid-discharge-feeding circuit kept the inlet sediment flux constant during all experiments. As both feeding rates did not present variation, changes in outlet solid discharge were assumed to be due to bed variations in the bed storage. We observed strong fluctuations of solid flux and slope in each reaches of all runs between: (i) steep aggradating armoured bed and (ii) less steep and finer bed releasing bedload sheets during erosion events and inducing bedload pulses. All experiments showed consistent results: transported volume associated with erosion event decreased with the length between two subsequent check dams. Solid transversal structures shorten the upstream erosion-propagation and avoid downstream change in the

  10. Experimental and discrete element numerical analysis of side slope instability induced by fissure water underlying impervious bed

    Institute of Scientific and Technical Information of China (English)

    LIU; Bingshan; LI; Shihai; ZHANG; Lei

    2005-01-01

    When the sliding mass contains impervious bed, rainfall can infiltrate into mountain via crevices and form higher artesian aquifer at impervious bed inferior. This will decrease slip resistance and increase sliding forces of the sliding mass, thus lowering the safety factor, and inducing landslide disasters. In this paper, a landslide experimental apparatus is designed for experimental studies on the mechanism of this type of landslides. Meanwhile, the non-dimensional parameters in the model experiment are taken into account using dimensional analysis. The experimental results show that (1) the ratio of the cleft water pressure to the overlying pressure is a crucial parameter affecting the stability of the slope; (2) when the shut-in pressure reaches 80% of the normal component of the pressure on the slip surface made up of rock and soil, landslide will occur; (3) the whole slope will start to slide when the shut-in pressure is equal to the normal component of the pressure formed by the overlying rock and soil on the upper 30% area. In this article, a discrete element method simulation is used to investigate the influence of cleft water pressure and shearing strength on the landslide stability. It can be concluded that the critical value of Ccr, ψcr, which determines the slide mass stability,increases with the increase of the water pressure; if the water pressure reaches a high level, the stability of the slide mass depends mainly on C, while the influence of ψ becomes smaller than C.

  11. Effects of rainfall infiltration on deep slope failure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    With the finite element method and the limit equilibrium method, a numerical model has been established for examining the effects of rainfall infiltration on the stability of slopes. This model is able to availably reflect the variations in pore pressure field in slopes, dead weight of soil, and the softening of soil strength caused by rainfall infiltration. As a case study, an actual landslide located at the Nongji Jixiao in Chongqing is studied to analyze the effects of rainfall infiltration on the seepage field and the slope stability. The simulated results show that a deep slope failure is prone to occur when rainfall infiltration will lead to a remarkable variation in the seepage field, in particular, for large range pore water pressure increase in slopes.

  12. Effects of rainfall infiltration on deep slope failure

    Institute of Scientific and Technical Information of China (English)

    SUN JianPing; LIU QingQuan; LI JiaChun; AN Yi

    2009-01-01

    With the finite element method and the limit equilibrium method, a numerical model has been estab-lished for examining the effects of rainfall infiltration on the stability of slopes. This model is able to availably reflect the variations in pore pressure field in slopes, dead weight of soil, and the softening of soil strength caused by rainfall infiltration. As a case study, an actual landslide located at the Nongji Jixiao in Chongqing is studied to analyze the effects of rainfall infiltration on the seepage field and the slope stability. The simulated results show that a deep slope failure is prone to occur when rainfall infiltration will lead to a remarkable variation in the seepage field, in particular, for large range pore water pressure increase in slopes.

  13. Loading and Unloading Finishing Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

    Directory of Open Access Journals (Sweden)

    Arlene Garcia

    2014-12-01

    Full Text Available The use of non-slip surfaces during loading and unloading of finishing pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps with a slope below 20 degrees to load and unload pigs. However, the total time it takes to load and unload animals and slips, falls, and vocalizations are a welfare concern. Three ramp angles (0, 10 or 20 degrees, five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay, two moistures (dry or wet bedding, >50% moisture over two seasons (>23.9 °C summer, <23.9 °C winter were assessed for slips/falls/vocalizations (n = 2400 pig observations and analyzed with a scoring system. The use of bedding during summer or winter played a role in the total time it took to load and unload the ramp (p < 0.05. Bedding, bedding moisture, season, and slope significantly interacted to impact the total time to load and unload finishing pigs (p < 0.05. Heart rate and the total time it took to load and unload the ramp increased as the slope of the ramp increased (p < 0.05. Heart rates were higher during the summer than winter, and summer heart rates increased as the slope increased (p < 0.05. The current study suggests that several factors should be considered in combination to identify the appropriate bedding for the specific occasion.

  14. Recharge-induced groundwater flow over a plane sloping bed: Solutions for steady and transient flow using physical and numerical models

    Science.gov (United States)

    Chapman, T. G.

    2005-07-01

    The free surface profile and outflow hydrograph for groundwater under conditions of steady uniform recharge followed by recession have been studied in viscous fluid model tests, using a sloping bed with a gradient of 0.2. The data have been compared with the nonlinear Boussinesq model and a modification of that model simulating the outflow seepage surface, obtained from a finite difference solution of the free boundary problem. It is shown that for a given bed slope, there is close to a linear relationship between outflow and storage raised to a power n, where n ranges from almost 2 for zero slopes to just above 1 at a gradient of 0.3. There is also a simple relationship between outflow and storage in the final stage of recession, when a drainage front occurs on the bed. These results lead to simple algorithms for prediction of the outflow under unsteady recharge conditions.

  15. Fluctuations of bed load solid discharge and grain size distribution on steep slopes with image analysis

    Energy Technology Data Exchange (ETDEWEB)

    Frey, P. [Erosion Torrentielle, Neige et Avalanche Research Unit, Cemagref Grenoble, B.P. 76, 38402, Saint-Martin d' Heres (France); Ducottet, C.; Jay, J. [Traitement du Signal et Instrumentation Laboratory, University of Saint Etienne, 23 rue du Dr Michelon, 42023, St Etienne cedex 2 (France)

    2003-12-01

    A new device using image analysis has been designed to measure the grain size distribution and the solid discharge of natural particles downstream of an experimental mobile bed flume. Experiments were performed in a 10 cm wide, 15% steep flume, with both uniform (4-5 mm) and non-uniform materials (3-15 mm). For the uniform material, outgoing solid discharge fluctuations were not significant, whereas they were large for the non-uniform material. The lower solid discharges were coarser than the higher solid discharges; this behavior is associated with the smallest particles playing a major role through building and destroying transient antidune-like bedforms. (orig.)

  16. Stability analysis of slopes of expansive soils considering rainfall effect

    Institute of Scientific and Technical Information of China (English)

    ZHU Fang-cai

    2007-01-01

    Typical failure types of slopes of expansive soils are divided to two kinds: slip in surface layer and slip in shallow layer. Based on total strength law of expansive soils, the relationship between its water content and shear strength inculding cohesion and friction angle, was studied in detail. Acoording to change of water content and depth effect during rainfall, distribution of shear strength in slopes of expansive soils was analyzed. Finally,with a slope of expansive soils in Nanning city of Guangxi Autonomous Region of China as a case, safety factor and slip surface was studied.

  17. Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

    Directory of Open Access Journals (Sweden)

    Arlene Garcia

    2014-12-01

    Full Text Available The use of non-slip surfaces during loading and unloading of weaned pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps below 20° to load and unload pigs. Three ramp angles (0°, 10° or 20°, five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay, two moistures (dry or wet bedding; >50% moisture over two seasons (>23.9 °C summer, <23.9 °C winter were assessed for slips/falls/vocalizations (n = 6,000 pig observations. “Score” was calculated by the sum of slips, falls, and vocalizations. With the exception of using feed as a bedding, all beddings provided some protection against elevated slips, falls, and vocalizations (P < 0.01. Providing bedding reduced (P < 0.05 scores regardless of whether the bedding was dry or wet. Scores increased as the slope increased (P < 0.01. Provision of bedding, other than feed, at slopes greater than zero, decreased slips, falls and vocalizations. The total time it took to load and unload pigs was

  18. Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture.

    Science.gov (United States)

    Garcia, Arlene; McGlone, John J

    2014-01-01

    The use of non-slip surfaces during loading and unloading of weaned pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps below 20° to load and unload pigs. Three ramp angles (0°, 10° or 20°), five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay), two moistures (dry or wet bedding; >50% moisture) over two seasons (>23.9 °C summer, pig observations). "Score" was calculated by the sum of slips, falls, and vocalizations. With the exception of using feed as a bedding, all beddings provided some protection against elevated slips, falls, and vocalizations (P feed, at slopes greater than zero, decreased slips, falls and vocalizations. The total time it took to load and unload pigs was affected by bedding type, ramp angle, and season (P pigs improved animal welfare. PMID:26479010

  19. Effects Of Exercise During Prolonged Bed Rest

    Science.gov (United States)

    Arnaud, S.; Berry, P; Cohen, M.; Danelis, J.; Deroshia, C.; Greenleaf, J.; Harris, B.; Keil, L.; Bernauer, E.; Bond, M.; Ellis, S.; Lee, P.; Selzer, R.; Wade, C.

    1992-01-01

    Report describes experiment to investigate effects of isotonic and isokinetic leg exercises in counteracting effects of bed rest upon physical and mental conditions of subjects. Data taken on capacity for work, endurance and strength, tolerance to sitting up, equilibrium, posture, gait, atrophy, mineralization and density of bones, endocrine analyses concerning vasoactivity and fluid and electrolyte balances, intermediary metabolism of muscles, mood, and performance.

  20. Effect of subthreshold slope on the sensitivity of nanoribbon sensors

    Science.gov (United States)

    Sun, K.; Zeimpekis, I.; Hu, C.; Ditshego, N. M. J.; Thomas, O.; de Planque, M. R. R.; Chong, H. M. H.; Morgan, H.; Ashburn, P.

    2016-07-01

    In this work, we investigate how the sensitivity of a nanowire or nanoribbon sensor is influenced by the subthreshold slope of the sensing transistor. Polysilicon nanoribbon sensors are fabricated with a wide range of subthreshold slopes and the sensitivity is characterized using pH measurements. It is shown that there is a strong relationship between the sensitivity and the device subthreshold slope. The sensitivity is characterized using the current sensitivity per pH, which is shown to increase from 1.2% ph‑1 to 33.6% ph‑1 as the subthreshold slope improves from 6.2 V dec‑1 to 0.23 V dec‑1 respectively. We propose a model that relates current sensitivity per pH to the subthreshold slope of the sensing transistor. The model shows that sensitivity is determined only on the subthreshold slope of the sensing transistor and the choice of gate insulator. The model fully explains the values of current sensitivity per pH for the broad range of subthreshold slopes obtained in our fabricated nanoribbon devices. It is also able to explain values of sensitivity reported in the literature, which range from 2.5% pH‑1 to 650% pH‑1 for a variety of nanoribbon and nanowire sensors. Furthermore, it shows that aggressive device scaling is not the key to high sensitivity. For the first time, a figure-of-merit is proposed to compare the performance of nanoscale field effect transistor sensors fabricated using different materials and technologies.

  1. Loading and Unloading Finishing Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture.

    Science.gov (United States)

    Garcia, Arlene; McGlone, John J

    2014-01-01

    The use of non-slip surfaces during loading and unloading of finishing pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps with a slope below 20 degrees to load and unload pigs. However, the total time it takes to load and unload animals and slips, falls, and vocalizations are a welfare concern. Three ramp angles (0, 10 or 20 degrees), five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay), two moistures (dry or wet bedding, >50% moisture) over two seasons (>23.9 °C summer, pig observations) and analyzed with a scoring system. The use of bedding during summer or winter played a role in the total time it took to load and unload the ramp (p pigs (p < 0.05). Heart rate and the total time it took to load and unload the ramp increased as the slope of the ramp increased (p < 0.05). Heart rates were higher during the summer than winter, and summer heart rates increased as the slope increased (p < 0.05). The current study suggests that several factors should be considered in combination to identify the appropriate bedding for the specific occasion. PMID:26479134

  2. Formal deduction of the Saint-Venant-Exner model including arbitrarily sloping sediment beds and associated energy

    CERN Document Server

    Fernández-Nieto, E D; Narbona-Reina, G; Zabsonré, J D

    2015-01-01

    In this work we present a deduction of the Saint-Venant-Exner model through an asymptotic analysis of the Navier-Stokes equations. A multi-scale analysis is performed in order to take into account that the velocity of the sediment layer is smaller than the one of the fluid layer. This leads us to consider a shallow water type system for the fluid layer and a lubrication Reynolds equation for the sediment one. This deduction provides some improvements with respect to the classical Saint-Venant-Exner model: (i) the deduced model has an associated energy. Moreover, it allows us to explain why classical models do not have an associated energy and how to modify them in order to recover a model with this property. (ii) The model incorporates naturally a necessary modification that must be taken into account in order to be applied to arbitrarily sloping beds. Furthermore, we show that this modification is different of the ones considered classically, and that it coincides with a classical one only if the solution ha...

  3. The effects of plant density of Melastoma malabathricum on the erosion rate of slope soil at different slope orientations

    Institute of Scientific and Technical Information of China (English)

    Aimee Halim n; Osman Normaniza

    2015-01-01

    abstract Malaysia's cut slopes, especially for road lines accommodation, are prone to erosions and landslides. These problems mainly occur due to lack of vegetation cover and strong erosive forces. In addition, the topography factors have also become a major factor affecting soil degradation. Thus, this study is aimed at determining the effects of planting density of a selected species, namely Melastoma malabathricum;one, two, and three seedlings per box, on the erosion rate at selected slopes of different orientation (morning and evening sun) at the Guthrie Corridor Expressway, Selangor. In six months of observation, treatment with three seedlings/box on the morning sun slope showed a lower erosion rate by 69.2%than those with the same treatment on the evening sun slope. In addition, the treatment of the three seedlings recorded at month six (final observation) had the highest reduction of soil saturation level (STL), by 23.6%. Furthermore, the physiological values of the species studied, grown on the morning sun slope, were higher in terms of stomatal conductance and photosynthetic rate by 12.1%and15.8%(three seedlings/box), respectively. The overall results showed that plant density was inversely related to the STL and erosion rate on the slope. In conclusion, a planting density of three seedlings/box and morning sun orientation gave positive effects on the plant's physiological performance of the slope, reducing the STL, as well as alleviating the erosion rate of slope soils.

  4. Source and depositional processes of coarse-grained limestone event beds in Frasnian slope deposits (Kostomłoty-Mogiłki quarry, Holy Cross Mountains, Poland)

    Science.gov (United States)

    Vierek, Aleksandra

    2010-10-01

    The Kostomłoty-Mogiłki succession is situated in the Kostomłoty transitional zone between the shallow-water Kielce stromatoporoid-coral platform and the deeper Łysogóry basin. In the Kostomłoty-Mogiłki quarry, the upper part of the Szydłówek Beds and Kostomłoty Beds are exposed. The Middle-Upper Frasnian Kostomłoty Beds are composed of shales, micritic and nodular limestones with abundant intercalations of detrital limestones. The dark shales and the micritic and nodular limestones record background sedimentation. The interbedded laminated and detrital limestones reflect high-energy deposition (= event beds). These event beds comprise laminated calcisiltites, fine-grained calcarenites, coarse-grained grain-supported calcirudites fabrics, and matrix-supported calcirudites. The material of these event beds was supplied by both erosion of the carbonate-platform margin and cannibalistic erosion of penecontemporaneous detrital limestones building the slope of this platform. Storms and the tectonic activity were likely the main causes of erosion. Combined and gravity flows were the transporting mechanisms involved in the reworking and redeposition.

  5. Effects of Topographic Slopes on Hydrological Proecsses and Climate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on previous research results on river re-distribution models, a modification on the effects of topographic slopes for a runoff parameterization was proposed and implemented to the NCAR's land sur face model (LSM). This modification has two aspects: firstly, the topographic slopes cause outflows from higher topography and inflows into the lower topography points; secondly, topographic slopes also cause decrease of infiltration at higher topography and increases of infiltration at lower topography. Then changes in infiltration result in changes in soil moisture, surface fluxes and then in surface temperature, and eventual ly in the upper atmosphere and the climate. This mechanism is very clearly demonstrated in the point bud gets analysis at the Andes Mountains vicinities. Analysis from a regional scale perspective in the Mackenzie GEWEX Study (MAGS) area, the focus of the ongoing Canadian GEWEX program, shows that the modi fied runoff parameterization does bring significant changes in the regional surface climate. More important ly, detailed analysis from a global perspective shows many encouraging improvements introduced by the modified LSM over the original model in simulating basic atmospheric climate properties such as thermodynamic features (temperature and humidity). All of these improvements in the atmospheric climate simulation illustrate that the inclusion of topographic effects in the LSM can force the AGCM to produce a more realistic model climate.

  6. Effect of bed configuration on pebble flow uniformity and stagnation in the pebble bed reactor

    International Nuclear Information System (INIS)

    Highlights: • Pebble flow uniformity and stagnation characteristics are very important for HTR-PM. • Arc- and brachistochrone-shaped configuration effects are studied by DEM simulation. • Best bed configurations with uniform flow and no stagnated pebbles are suggested. • Detailed quantified characteristics of bed configuration effects are shown for explanation. - Abstract: Pebble flow uniformity and stagnation characteristics are very important for the design of pebble bed high temperature gas-cooled reactor. Pebble flows inside some specifically designed contraction configurations of pebble bed are studied by discrete element method. The results show the characteristics of stagnation rates, recycling rates, radial distribution of pebble velocity and residence time. It is demonstrated clearly that the bed with a brachistochrone-shaped configuration achieves optimum levels of flow uniformity and recycling rate concentration, and almost no pebbles are stagnated in the bed. Moreover, the optimum choice among the arc-shaped bed configurations is demonstrated too. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity. In addition, a good design of the pebble bed configuration is suggested

  7. CFD-DEM study of effect of bed thickness for bubbling fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Tingwen Li; Pradeep Gopalakrishnana; Rahul Garg; Mehrdad Shahnam

    2012-01-01

    The effect of bed thickness in rectangular fluidized beds is investigated through the CFD-DEM simulations of small-scale systems.Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing,bed expansion,bubble behavior,solids velocities,and particle kinetic energy.Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters.However,a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters,indicating the transition from 2D flow to 3D flow within the range of 20-40 particle diameters.Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds.Hence,for quantitative comparison with experiments in pseudo-2D columns,the effect of wails has to be accounted for in numerical simulations.

  8. CFD-DEM study of effect of bed thickness for bubbling fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Tingwen, Li; Gopalakrishnan, Pradeep; Garg, Rahul; Shahnam, Mehrdad

    2011-10-01

    The effect of bed thickness in rectangular fluidized beds is investigated through the CFD–DEM simulations of small-scale systems. Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing, bed expansion, bubble behavior, solids velocities, and particle kinetic energy. Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters. However, a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters, indicating the transition from 2D flow to 3D flow within the range of 20–40 particle diameters. Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds. Hence, for quantitative comparison with experiments in pseudo-2D columns, the effect of walls has to be accounted for in numerical simulations.

  9. Effect of slope angle of an artificial pool on distributions of turbulence

    Institute of Scientific and Technical Information of China (English)

    Atefeh Fazlollahi; Hossein Afzalimehr; Jueyi Sui

    2015-01-01

    abstract Experiments were carried out over a 2-dimentional pool with a constant length of 1.5 m and four different slopes. The distributions of velocity, Reynolds stress and turbulence intensities have been studied in this paper. Results show that as flow continues up the exit slope, the flow velocity increases near the channel bed and decreases near the water surface. The flow separation was not observed by ADV at the crest of the bed-form. In addition, the length of the separation zone increases with the increasing of entrance and exit slopes. The largest slope angle causes the maximum normalized shear stress. Based on the experiments, it is concluded that the shape of Reynolds stress distribution is generally dependent on the entrance and exit slopes of the pool. Also, the shape of Reynolds stress distribution is affected by both decelerating and accelerating flows. Additionally, with the increase in the slope angle, secondary currents are developed and become more stable. Results of the quadrant analysis show that the momentum between flow and bed-form is mostly transferred by sweep and ejection events.&2015 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research. Published by Elsevier B.V. All rights reserved.

  10. Stochastic-deterministic modeling of bed load transport in shallow water flow over erodible slope: Linear stability analysis and numerical simulation

    Science.gov (United States)

    Bohorquez, Patricio; Ancey, Christophe

    2015-09-01

    In this article we propose a stochastic bed load transport formulation within the framework of the frictional shallow-water equations in which the sediment transport rate results from the difference between the entrainment and deposition of particles. First we show that the Saint-Venant-Exner equations are linearly unstable in most cases for a uniform base flow down an inclined erodible bed for Shields numbers in excess of the threshold for incipient sediment motion allowing us to compute noise-induced pattern formation for Froude numbers below 2. The wavelength of the bed forms are selected naturally due to the absolute character of the bed instability and the existence of a maximum growth rate at a finite wavelength when the particle diffusivity coefficient and the water eddy viscosity are present as for Turing-like instability. A numerical method is subsequently developed to analyze the performance of the model and theoretical results through three examples: the simulation of the fluctuations of the particle concentration using a stochastic Langevin equation, the deterministic simulation of anti-dunes formation over an erodible slope in full sediment-mobility conditions, and the computation of noise-induced pattern formation in hybrid stochastic-deterministic flows down a periodic flume. The full non-linear numerical simulations are in excellent agreement with the theoretical solutions. We conclude highlighting that the proposed depth-averaged formulation explains the developments of upstream migrating anti-dunes in straight flumes since the seminar experiments by Gilbert (1914).

  11. Effect of bed particles to combustion of gases in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Raiko, R.; Wallen, V.; Etelaeaho, R.; Correia, S. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

    1997-10-01

    The objective of this project was to obtain experimental data on effects of sand particles to the combustion of gases. The effect of the surface area of the particles was tested using different sized particles. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 42 mm surrounded by an electric heater. The test rig was built in the Laboratory of Energy and Process Engineering at Tampere University of Technology. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies were conducted with both fresh bed particles and used bed particles. These measurements indicate that carbon monoxide significantly reacts with oxygen in the particulate or emulsion phase of a fluidized bed, if the residence time is long enough. The reaction rate depends mainly on temperature, air coefficient, residence time and particle size of the solids. It seems that the combustion enhances if the average particle size increases. Whether this is caused by increased free path length or reduced specific surface area of the bed is yet unknown. The first might be more probable cause because the majority of reactions often took place in the freeboard right above the bed. It was clear that the bed hindered proper combustion in several cases. (orig.)

  12. Effects of bed-load movement on flow resistance over bed forms

    Indian Academy of Sciences (India)

    Mohammad Hossein Omid; Masoud Karbasi; Javad Farhoudi

    2010-12-01

    The effect of bed-load transport on flow resistance of alluvial channels with undulated bed was experimentally investigated. The experiments were carried out in a tilting flume 250 mm wide and 12·5 m long with glass-sides of rectangular cross-section and artificial dune shaped floor that was made from Plexi-glass. Steady flow of clear as against sediment-laden water with different flow depths and velocities were studied in the experiments with a fine sand ($d_{50} =$ 0·5 mm). The results indicate that the transport of fine particles ($d_{50} =$ 0·5 mm) can decrease the friction factor by 22% and 24% respectively for smooth and rough beds. Increasing the bed-load size ($d_{50} =$ 2·84 mm) can decrease the friction factor by 32% and 39% respectively for smooth and rough beds. The decrease in flow resistance is due to filling up of the troughs of dunes. This separation zone is responsible for increasing the flow resistance. On the upstream side of dunes condition is similar to plane bed. Presence of bed-load causes to increase the shear velocity and hence increasing flow resistance. But decreasing in flow resistance is more and it causes to decrease the total flow resistance. Grains saturated the troughs in the bed topography, effectively helping in smoothening of bed irregularities.

  13. Loading and Unloading Finishing Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

    OpenAIRE

    Arlene Garcia; McGlone, John J.

    2014-01-01

    Simple Summary Current guidelines suggest the use of ramps below 20 degrees to load and unload pigs; however, they do not suggest the use of any specific bedding. Bedding types (nothing, feed, sand, wood shavings, and hay) were tested with finishing pigs (70–120 kg) to determine which was most effective in reducing slips, falls, and vocalizations at three ramp angles, two moisture levels, over two seasons. Slips, falls, and vocalizations were summed to establish a scoring system for the types...

  14. Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

    OpenAIRE

    2014-01-01

    Simple Summary Current guidelines suggest the use of ramps below 20° to load and unload pigs; they do not suggest the use of any specific bedding. Bedding types (nothing, feed, sand, wood shavings, and hay) were tested with four week old weaned pigs to determine which was most effective in reducing slips, falls, and vocalizations at three ramp angles, two moistures, over two seasons. Slips, falls, and vocalizations were summed to establish a scoring system to evaluate treatments. Scores incre...

  15. Analysis of effective solid stresses in a conical spouted bed

    OpenAIRE

    A. L. T. CHARBEL; G. Massarani; PASSOS M. L.

    1999-01-01

    Some applications of spouted beds have been limited by problems with spout stability. In order to overcome these limitations, research should be concentrated on describing the mechanism by which the spout is developed. This work presents a theoretical and experimental study to describe the effective solid stress distribution in the annular region of a conical spouted bed. From experimental observation, the failure state of the bed of particles at the outset of spouting is identified and relat...

  16. Variance-in-Mean Effects of the Long Forward-Rate Slope

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    2005-01-01

    This paper contains an empirical analysis of the dependence of the long forward-rate slope on the long-rate variance. The long forward-rate slope and the long rate are described by a bivariate GARCH-in-mean model. In accordance with theory, a negative long-rate variance-in-mean effect for the long...... forward-rate slope is documented. Thus, the greater the long-rate variance, the steeper the long forward-rate curve slopes downward (the long forward-rate slope is negative). The variance-in-mean effect is both statistically and economically significant....

  17. The Effect of Bedding Structure on Mechanical Property of Coal

    Directory of Open Access Journals (Sweden)

    Zetian Zhang

    2014-01-01

    Full Text Available The mechanical property of coal, influencing mining activity considerably, is significantly determined by the natural fracture distributed within coal mass. In order to study the effecting mechanism of bedding structure on mechanical property of coal, a series of uniaxial compression tests and mesoscopic tests have been conducted. The experimental results show that the distribution characteristic of calcite particles, which significantly influences the growth of cracks and the macroscopic mechanical properties of coal, is obviously affected by the bedding structure. Specifically, the uniaxial compression strength of coal sample is mainly controlled by bedding structure, and the average peak stress of specimens with axes perpendicular to the bedding planes is 20.00 MPa, which is 2.88 times the average amount of parallel ones. The test results also show a close relationship between the bedding structure and the whole deformation process under uniaxial loading.

  18. Soils of sinkholes: effects of slope aspect and lateral transport of sediments on soil variation

    Science.gov (United States)

    Smirnova, Maria; Tsibart, Anna; Abramova, Anna; Koshovskii, Timur; Gennadiev, Alexander

    2015-04-01

    Karst landscapes are highly fragile and particularly vulnerable to subsidence and soil erosion. In karst region there may be hundreds or even thousands of sinkholes and other karst landforms in a small area so that the flat surface is actually absent. The effect of slope aspect on karst landscapes are resulted in different amount of solar radiation and increase of moisture along slopes. In European Russia semiarid landscapes the wind transport of the snow resulted in addition moistening of the soil situated on the eastern slope of depressions. Our research is devoted to the investigation of soil catenas on the slopes of subsidence sinkhole in "Bogdo-Baskuntschak" natural reserve (semiarid landscape). It based on field research of 4 soil catenas situated on the slopes of eastern, northern, western and south exposures. The profile of the sinkhole is an inverted cone (elongated from west to east), slope length varies from 8 to 12 meters, slope gradient - between 40-55% (eastern slope is the shortest and steepest). The short slope length and soil diversity that the sinkholes provided are beneficial for investigation of slope aspect and effect of lateral transport on soil formation. The main feature of sinkhole soil cover is a considerable variety and their high complexity. The lateral transport of sediments resulted in dramatic changes of soil within catenas. Haplic calcisols and arenosols calcaric, situated on the inter-sinkhole flat surface and upper parts of the slopes are substituted by cambisols and leptosols in the middle part of the slopes and colluvic regosols humic in the lower part of the slopes and sinkhole bottom. Soil formation and accumulation of sediments occur simultaneously and lead to the weak soil formation at the middle and lower sections of sinkhole side slopes. The thickness of humus horizon increases from the top to the bottom of sinkhole notably - from 8-12 cm on the upper and middle part of the slopes to 240 cm on the bottom of the sinkhole

  19. Bed of polydisperse viscous spherical drops under thermocapillary effects

    Science.gov (United States)

    Sharanya, V.; Raja Sekhar, G. P.; Rohde, Christian

    2016-08-01

    Viscous flow past an ensemble of polydisperse spherical drops is investigated under thermocapillary effects. We assume that the collection of spherical drops behaves as a porous media and estimates the hydrodynamic interactions analytically via the so- called cell model that is defined around a specific representative particle. In this method, the hydrodynamic interactions are assumed to be accounted by suitable boundary conditions on a fictitious fluid envelope surrounding the representative particle. The force calculated on this representative particle will then be extended to a bed of spherical drops visualized as a Darcy porous bed. Thus, the "effective bed permeability" of such a porous bed will be computed as a function of various parameters and then will be compared with Carman-Kozeny relation. We use cell model approach to a packed bed of spherical drops of uniform size (monodisperse spherical drops) and then extend the work for a packed bed of polydisperse spherical drops, for a specific parameters. Our results show a good agreement with the Carman-Kozeny relation for the case of monodisperse spherical drops. The prediction of overall bed permeability using our present model agrees well with the Carman-Kozeny relation when the packing size distribution is narrow, whereas a small deviation can be noted when the size distribution becomes broader.

  20. The Dynamic Evaluation of Rock Slope Stability Considering the Effects of Microseismic Damage

    Science.gov (United States)

    Xu, N. W.; Dai, F.; Liang, Z. Z.; Zhou, Z.; Sha, C.; Tang, C. A.

    2014-03-01

    A state-of-the-art microseismic monitoring system has been implemented at the left bank slope of the Jinping first stage hydropower station since June 2009. The main objectives are to ensure slope safety under continuous excavation at the left slope, and, very recently, the safety of the concrete arch dam. The safety of the excavated slope is investigated through the development of fast and accurate real-time event location techniques aimed at assessing the evolution and migration of the seismic activity, as well as through the development of prediction capabilities for rock slope instability. Myriads of seismic events at the slope have been recorded by the microseismic monitoring system. Regions of damaged rock mass have been identified and delineated on the basis of the tempo-spatial distribution analysis of microseismic activity during the periods of excavation and consolidation grouting. However, how to effectively utilize the abundant microseismic data in order to quantify the stability of the slope remains a challenge. In this paper, a rock mass damage evolutional model based on microseismic data is proposed, combined with a 3D finite element method (FEM) model for feedback analysis of the left bank slope stability. The model elements with microseismic damage are interrogated and the deteriorated mechanical parameters determined accordingly. The relationship between microseismic activities induced by rock mass damage during slope instability, strength degradation, and dynamic instability of the slope are explored, and the slope stability is quantitatively evaluated. The results indicate that a constitutive relation considering microseismic damage is concordant with the simulation results and the influence of rock mass damage can be allowed for its feedback analysis of 3D slope stability. In addition, the safety coefficient of the rock slope considering microseismic damage is reduced by a value of 0.11, in comparison to the virgin rock slope model. Our results

  1. Buoyancy Effect on MHD Flow Past a Permeable Bed

    OpenAIRE

    S. Venkataramana; D. Bathaiah

    1986-01-01

    In this paper, the effect of buoyancy force on the parallel flows bounded above by a rigid permeable plate which may be moving or stationary and below, by a permeable bed has been investigated. To discuss the solution, the flow region is divided into two zones. In Zone 1, the flow is laminar and is governed by the Navier-Stokes equations from the impermeable upper rigid plate to the permeable bed. In Zone 2, the flow is governed by the Darcy law in the permeable bed below the nominal surface....

  2. Study of the influence of fuel load and slope on a fire spreading across a bed of pine needles by using oxygen consumption calorimetry

    International Nuclear Information System (INIS)

    A set of experiments using a Large Scale Heat Release Rate Calorimeter was conducted to test the effects of slope and fuel load on the fire dynamics. Different parameters such as the geometry of the flame front, the rate of spread, the mass loss rate and the heat release rate were investigated. Increasing the fuel load or the slope modifies the fire behaviour. As expected, the flame length and the rate of spread increase when fuel load or slope increases. The heat release rate does not reach a quasi-steady state when the propagation takes place with a slope of 20° and a high fuel load. This is due to an increase of the length of the fire front leading to an increase of fuel consumed. These considerations have shown that the heat release can be estimated with the mass loss rate by considering the effective heat of combustion. This approach can be a good alternative to estimate accurately the fireline intensity when the measure of oxygen consumption is not possible.

  3. Meteorological, elevation, and slope effects on surface hoar formation

    Science.gov (United States)

    Horton, S.; Schirmer, M.; Jamieson, B.

    2015-08-01

    Failure in layers of buried surface hoar crystals (frost) can cause hazardous snow slab avalanches. Surface hoar crystals form on the snow surface and are sensitive to micro-meteorological conditions. In this study, the role of meteorological and terrain factors was investigated for three layers of surface hoar in the Columbia Mountains of Canada. The distribution of crystals over different elevations and aspects was observed on 20 days of field observations during a period of high pressure. The same layers were modelled over simplified terrain on a 2.5 km horizontal grid by forcing the snow cover model SNOWPACK with forecast weather data from a numerical weather prediction model. Modelled surface hoar growth was associated with warm air temperatures, high humidity, cold surface temperatures, and low wind speeds. Surface hoar was most developed in regions and elevation bands where these conditions existed, although strong winds at high elevations caused some model discrepancies. SNOWPACK simulations on virtual slopes systematically predicted smaller surface hoar on south-facing slopes. In the field, a complex combination of surface hoar and sun crusts were observed, suggesting the simplified model did not adequately resolve the surface energy balance on slopes. Overall, a coupled weather-snow cover model could benefit avalanche forecasters by predicting surface hoar layers on a regional scale over different elevation bands.

  4. Bootstrap method for characterizing the effect of uncertainty in shear strength parameters on slope reliability

    International Nuclear Information System (INIS)

    This paper aims to propose a bootstrap method for characterizing the effect of uncertainty in shear strength parameters on slope reliability. The procedure for a traditional slope reliability analysis with fixed distributions of shear strength parameters is presented first. Then, the variations of the mean and standard deviation of shear strength parameters and the Akaike Information Criterion values associated with various distributions are studied to characterize the uncertainties in distribution parameters and types of shear strength parameters. The reliability of an infinite slope is presented to demonstrate the validity of the proposed method. The results indicate that the bootstrap method can effectively model the uncertain probability distributions of shear strength parameters. The uncertain distributions of shear strength parameters have a significant influence on slope reliability. With the bootstrap method, the slope reliability index is represented by a confidence interval instead of a single fixed index. The confidence interval increases with increasing factor of slope safety. Considering both the uncertainties in distribution parameters and distribution types of shear strength parameters leads to a higher variation and a wider confidence interval of reliability index. - Highlights: • A bootstrap method is proposed to characterize effect of uncertainty on reliability. • An infinite slope is studied to demonstrate validity of bootstrap method. • The bootstrap method can effectively model uncertain probability distributions. • Slope reliability index is a confidence interval instead of a single fixed index. • Confidence interval of reliability index increases with increasing factor of safety

  5. Short-term vegetation recovery after a spring grassland fire in Lithuania. Effect of time and slope position

    Directory of Open Access Journals (Sweden)

    P. Pereira

    2013-01-01

    Full Text Available The aim of this work is study the effects of a grassland fire in vegetation recuperation according to fire severity, slope exposition and position. We designed two experimental plots, one located in an east faced slope (Slope A and other in a west faced (Slope B. Vegetation recuperation was assessed 10, 17, 31 and 46 days after the fire. The results showed that fire severity was higher in slope B, than in slope A. In both slopes vegetation recuperation was different according position. Bottom positions recovered faster than slope and upslope positions, that it is attributed to fire severity (higher in slope and upslope areas and ash and soil transport and deposition in bottom areas. The vegetation recuperated faster in slope B and 46 days after the fire, 100% of the plot was covered. This was attributed to higher severity, more complex topography, and inclination of Slope A, that delayed the vegetation recover.

  6. Analysis of effective solid stresses in a conical spouted bed

    Directory of Open Access Journals (Sweden)

    CHARBEL A. L. T.

    1999-01-01

    Full Text Available Some applications of spouted beds have been limited by problems with spout stability. In order to overcome these limitations, research should be concentrated on describing the mechanism by which the spout is developed. This work presents a theoretical and experimental study to describe the effective solid stress distribution in the annular region of a conical spouted bed. From experimental observation, the failure state of the bed of particles at the outset of spouting is identified and related to fluid-particle properties and column dimensions. Linear and angular momentum balances for the solid phase are then formulated as a function of the bed failure state. The set of equations obtained is solved using numerical methods, and results regarding stress distribution, stability and spout shape are presented and discussed.

  7. Effects of equipment loadings on geosynthetic-lined slope behaviour.

    Science.gov (United States)

    Park, Hyun I; Lee, Seung R

    2005-06-01

    When combined in the lining and covering of waste-containment facilities, soil and geosynthetic components protect the environment by acting as a hydraulic barrier. Equipment loading may significantly increase the tensile stress induced in geosynthetic components, leading to a potential stability problem. Large equipment loadings may also result in a localized circular slip surface during construction operations. New analytical method based on discrete element modelling is proposed for estimating the distribution of tensile force developed in the individual geosynthetic components of the lining system and for evaluating the safety factor of slope failure due to equipment loading. The analytical results of an example are presented to demonstrate the applicability of the analytical method for the lining system of a waste landfill. The analyses of the example show that equipment loading provide a substantial increase in the tensile forces of the geosynthetic components of a lining system and that the possibility of shallow failure due to equipment loading increases as the slope becomes steeper. This method is a useful tool for analysing the lining system of waste landfills with complex lining components. PMID:15988943

  8. Effect of distance on trade under slope heterogeneity and cross-correlated effects

    OpenAIRE

    Lugovskyy, Oleksandr; Skiba, Alexandre

    2014-01-01

    The authors argue that endogeneity of transportation costs needs to be taken into account when estimating the effect of distance on trade. Otherwise, the estimates of the distance effect may be biased and inconsistent. Endogenous transportation can introduce slope heterogeneity and spatial correlation. Both issues can be accommodated with the help of Pesaran's cross-correlated effects mean-group (CCEMG) estimator. After applying this methodology, the authors uncover significant compression of...

  9. Stability analysis of sandy slope considering anisotropy effect in friction angle

    Indian Academy of Sciences (India)

    Hamed Farshbaf Aghajani; Hossein Salehzadeh; Habib Shahnazari

    2015-09-01

    This paper aims to investigate the effect of anisotropy of shear strength parameter on the stability of a sandy slope by performing the limit equilibrium analysis. Because of scarcity of mathematical equation for anisotropic friction angle of sand, at first, all results of principal stress rotation tests are processed by artificial neural network and a computational procedure is developed for determining sand friction angle subjected to various loading directions. By implementing this procedure, slope stability analysis is performed in both isotropic and anisotropic conditions. The results indicate that while isotropic slope stability overestimates the factor of safety between 5 and 25% which the deviation is more for flatter slope, the location of critical slip surface is coincident in both conditions. Also in specific slip surface, the parameters of face angle, geometry of slip surface and soil properties relating to anisotropy are the main factors governing the result of anisotropic slope stability.

  10. Buoyancy Effect on MHD Flow Past a Permeable Bed

    Directory of Open Access Journals (Sweden)

    S. Venkataramana

    1986-10-01

    Full Text Available In this paper, the effect of buoyancy force on the parallel flows bounded above by a rigid permeable plate which may be moving or stationary and below, by a permeable bed has been investigated. To discuss the solution, the flow region is divided into two zones. In Zone 1, the flow is laminar and is governed by the Navier-Stokes equations from the impermeable upper rigid plate to the permeable bed. In Zone 2, the flow is governed by the Darcy law in the permeable bed below the nominal surface. The expressions for velocity and temparature distributions, Slip velocity, slip temperature, mass flow rate and the rates of heat transfer coefficients are obtained. The effects of magnetic, porous, slip and buoyancy parameters and Biot number on the above physical quantities are investigated. The thickness of the boundary layer in Zone 2 has been evaluated.

  11. Effects of high salinity wastewater on methanogenic sludge bed systems

    NARCIS (Netherlands)

    Ismail, S.; Gonzalez-Contreras, P.A.; Jeison, D.A.; Lier, van J.B.

    2008-01-01

    The attainable loading potentials of anaerobic sludge bed systems are strongly dependent on the growth of granular biomass with a particular wastewater. Experiments were conducted to determine the effects of high salinity wastewater on the biological and physical properties of methanogenic sludge. S

  12. Effects of Skidder Passes and Slope on Soil Disturbance in Two Soil Water Contents

    OpenAIRE

    Naghdi, Ramin; Solgi, Ahmad

    2014-01-01

    Skidding operations induce changes in soil physical properties, which have the potential to impact soil sustainability and forest productivity. Our objective was to investigate the effects of traffic frequency, trail slope, and soil moisture content on soil compaction, total porosity and rut depth. Treatments included a combination of three different traffic intensities (3, 7, and 14 passes), three levels of slopes ( 20%), and two levels of soil moisture content (18% and 32...

  13. Surficial Stability Analysis of Unsaturated Loess Slopes Subjected to Rainfall Infiltration Effects

    Institute of Scientific and Technical Information of China (English)

    LI Xinpo; WANG Chenghua; XU Jun

    2006-01-01

    According to theory of unsaturated soil strength and Green-Ampt model, an analysis method based on limit equilibrium theory is introduced to consider rainfall infiltration effects in loess slope stability analysis. The relationships between wetting band depth and surficial stability of slopes are analyzed. It is found that the infiltration adds to the weight of the soil and at the same time reduces the shear strength provided by matric suction of the soil. The wetting band depth plays a key role in the stability of slopes. The minimum rainfall intensity and the minimum rainfall duration needed to infiltrate to the wetting front depth are calculated based on the Green-Ampt model. The method in this paper will contribute to the predication of slope stability considering rainfall characteristics.

  14. Effects of triggering mechanism on snow avalanche slope angles and slab depths from field data

    Science.gov (United States)

    McClung, David M.

    2013-04-01

    Field data from snow avalanche fracture lines for slope angle and slab depth (measured perpendicular to the weak layer) were analyzed for different triggering mechanisms. For slope angle, the results showed that the same probability density function (pdf) (of log-logistic type) and range (25 - 55 degrees) apply independent of triggering mechanism. For slab depth, the same pdf (generalized extreme value) applies independent of triggering mechanism. For both slope angle and slab depth, the data skewness differentiated between triggering mechanism and increased with applied triggering load. For slope angle, skewness is lowest for natural triggering by snow loads and highest for triggering from human intervention. For slab depth, the skewness is lowest for natural triggering and highest for a mix of triggers including explosive control with skier triggering being intermediate. The results reveal the effects of triggering mechanism which are important for risk analyses and to guide avalanche forecasting.

  15. Distribution of Lepidopteran Larvae on Norway Spruce: Effects of Slope and Crown Aspect.

    Science.gov (United States)

    Kulfan, Ján; Dvořáčková, Katarína; Zach, Peter; Parák, Michal; Svitok, Marek

    2016-04-01

    Lepidoptera associated with Norway spruce, Picea abies (L.) Karsten, play important roles in ecosystem processes, acting as plant pests, prey for predators, and hosts for parasites and parasitoids. Their distribution patterns in spruce crowns and forests are only poorly understood. We examined how slope and crown aspect affect the occurrence and abundance of moth larvae on solitary spruce trees in a montane region in Central Europe. Moth larvae were collected from southern and northern crowns of trees growing on south- and north-facing slopes (four treatments) using emergence boxes at the end of winter and by the beating method during the growing season. Species responses to slope and crown aspect were not uniform. Treatment effects on moth larvae were stronger in the winter than during the growing season. In winter, the abundance of bud-boring larvae was significantly higher in northern than in southern crowns regardless of the slope aspect, while both slope and aspect had marginally significant effects on abundance of miners. During the growing season, the occurrence of free-living larvae was similar among treatments. Emergence boxes and beating spruce branches are complementary techniques providing valuable insights into the assemblage structure of moth larvae on Norway spruce. Due to the uneven distribution of larvae detected in this study, we recommend adoption of a protocol that explicitly includes sampling of trees from contrasting slopes and branches from contrasting crown aspect in all seasons. PMID:26795212

  16. Effect of Bed Deformation on Natural Gas Production from Hydrates

    Directory of Open Access Journals (Sweden)

    Mohamed Iqbal Pallipurath

    2013-01-01

    Full Text Available This work is based on modelling studies in an axisymmetric framework. The thermal stimulation of hydrated sediment is taken to occur by a centrally placed heat source. The model includes the hydrate dissociation and its effect on sediment bed deformation and resulting effect on gas production. A finite element package was customized to simulate the gas production from natural gas hydrate by considering the deformation of submarine bed. Three sediment models have been used to simulate gas production. The effect of sediment deformation on gas production by thermal stimulation is studied. Gas production rate is found to increase with an increase in the source temperature. Porosity of the sediment and saturation of the hydrate both have been found to significantly influence the rate of gas production.

  17. In situ low-angle cross sectioning: Bevel slope flattening due to self-alignment effects

    International Nuclear Information System (INIS)

    Low-angle cross sections are produced inside an Auger microprobe using the equipped depth profile ion sputter gun. Simply the sample is partly covered by a mask. Utilizing the edge of this mask the sample is sputtered with ions. Due to the shading of the mask a cross section is produced in the sample. The slope of this cross section is considerably shallower than given by the geometrical setup. This is attributed to self-alignment effects, which are due to missing sputter cascades in the transition area between sputtered and shaded sample regions and a chamfering of the mask edge. These self-alignment effects are studied here using a 104.6 nm thick SiO2 layer thermally grown on a Si substrate. In this study on one hand for a fixed ion impact angle of 15.8 deg. as function of the sputter time several in situ low-angle cross sections were produced. This way slope angles between an ultimate low slope angle of 0.014 deg. and 0.085 deg. were achieved. On the other hand for a fixed sputter time the ion impact angle was varied between 14.8 deg. and 70.8 deg. For these samples cross section slope angles between 0.031 deg. and 0.32 deg. are observed. These results demonstrate the distinct slope flatting of in situ cross sectioning.

  18. Effects of the Symmetry Energy and its Slope on Neutron Star Properties

    CERN Document Server

    Lopes, L L

    2014-01-01

    In this work we study the influence of the symmetry energy and its slope on three major properties of neutron stars: the maximum mass, the radii of the canonical 1.4$M_\\odot$ and the minimum mass that enables the direct URCA effect. We utilize four parametrizations of the relativistic quantum hadrodynamics and vary the symmetry energy within accepted values. We see that although the maximum mass is almost independent of it, the radius of the canonical $1.4M_\\odot$ and the mass that enables the direct URCA effect is strongly correlated with the symmetry energy and its slope. Also, since we expect that the radius grows with the slope, a theoretical limit arises when we increase this quantity above certain values.

  19. Carbon sequestration in coal-beds with structural deformation effects

    International Nuclear Information System (INIS)

    Carbon dioxide sequestration in a coal-bed is a profitable method to reduce the concentration of greenhouse gas in the atmosphere and to recover byproduct methane from the coal seam. The important factor to be considered is the stability of the coal-bed with the increased carbon dioxide injection. It is crucial to avoid carbon dioxide escaping from the coal seam caused by structural deformation. Meanwhile, structural deformation also depends on such properties of the geological coal basin as fracture state and phase equilibrium, especially the porosity, permeability and saturation of the coal seam. In this study, a structural deformation effect was simulated with the purpose of predicting carbon dioxide storage in the environment of a typical unmineable coal seam. As an example, Appalachian Basin is considered in the deformation analysis of carbon dioxide sequestration based on the variable saturation model. Moreover, the comparison between simulations with and without the account of structural deformation is given. The results indicate that modeling of structural deformation in carbon sequestration is feasible by directly coupling structure terms to a variable saturated model. Moreover, introducing structural deformation effects into carbon sequestration modeling is important because it affects the fluid flow and leads to a faster drop of the resulting capillary pressure and relative permeability of the gas phase. This faster drop directly results in the diminished carbon dioxide storage capacity in a coal-bed basin. In addition, structural deformation modeling in carbon sequestration simulations can provide important insights into how to avoid carbon leakage and seepage by monitoring the effective stress and displacement of coal-bed basin during carbon dioxide injection.

  20. Occupational dust exposure and smoking. Different effects on forced expiration and slope of the alveolar plateau.

    Science.gov (United States)

    Rasmussen, F V

    1985-02-01

    Indices of forced expiration (FEV1 and MEF25-75) were compared with the slope of Phase III of the single breath nitrogen test (%N2/1) in 1270 men, who, based on life occupational histories, were categorized as cement factory workers, blue or white collar workers, and farmers. The slope of Phase III was successfully determined in 1182 men. Irrespective of occupational category, the FEV1 and MEF was lower in present smokers than in ex-smokers, who in turn had lower values than never-smokers. With corresponding smoking habits, white collar workers showed on average higher values of FEV1 and MEF than the blue collar workers, the cement-exposed men and the farm workers. The slope of Phase III varied with smoking habits in a similar way, and among present smokers, the same occupational gradient was evident. However, no effect of occupation on the slope of Phase III could be traced in ex-smokers and never-smokers. It is concluded that the response of the lung to occupational exposure may differ from that of tobacco smoking. The combined use of indices from the forced expirogram and the slope of Phase III could yield valuable information in the study of occupational respiratory diseases. PMID:3972021

  1. The effects of China’s Sloping Land Conversion Program on agricultural households

    DEFF Research Database (Denmark)

    Liu, Zhen; Henningsen, Arne

    In the late 1990s, China aimed to mitigate environmental degradation from agricultural production activities by introducing the world’s largest ’Payments for Environmental Services’ (PES) program ― the Sloping Land Conversion Program (SLCP). In order to analyze its effects on agricultural...

  2. EFFECT OF VERTICAL BAFFLES ON PARTICLE MIXING AND DRYING IN FLUIDIZED BEDS OF GROUP D PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Chung Lim Law; Siti Masrinda Tasirin; Wan Ramli Wan Daud; Derek Geldart

    2003-01-01

    This study reports the effect of vertical baffles on the group D powder mixing and drying characteristics in a batch fluidized bed dryer. Results obtained in this study showed that operating the fluidized bed dryer with vertical baffles gave better particle mixing. This is due to the fact that the vertical baffles acted to limit the growth of small bubbles into large bubbles and the small bubbles caused more vigorous mixing in the bed of particles before finally erupting at the bed surface. Thus, insertion of vertical baffles is a useful way to process group D particles in a fluidized bed, especially when the fluidized bed is large.

  3. Source and depositional processes of coarse-grained limestone event beds in Frasnian slope deposits (Kostomłoty-Mogiłki quarry, Holy Cross Mountains, Poland)

    OpenAIRE

    Vierek, Aleksandra

    2010-01-01

    The Kostomłoty-Mogiłki succession is situated in the Kostomłoty transitional zone between the shallow-water Kielce stromatoporoid-coral platform and the deeper Łysogóry basin. In the Kostomłoty-Mogiłki quarry, the upper part of the Szydłówek Beds and Kostomłoty Beds are exposed. The Middle-Upper Frasnian Kostomłoty Beds are composed of shales, micritic and nodular limestones with abundant intercalations of detrital limestones. The dark shales and the micritic and nodular limestones record bac...

  4. Deleterious Thermal Effects Due To Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

    Science.gov (United States)

    Moran, Robert P.

    2013-01-01

    A review of literature associated with Pebble Bed and Particle Bed reactor core research has revealed a systemic problem inherent to reactor core concepts which utilize randomized rather than structured coolant channel flow paths. For both the Pebble Bed and Particle Bed Reactor designs; case studies reveal that for indeterminate reasons, regions within the core would suffer from excessive heating leading to thermal runaway and localized fuel melting. A thermal Computational Fluid Dynamics model was utilized to verify that In both the Pebble Bed and Particle Bed Reactor concepts randomized coolant channel pathways combined with localized high temperature regions would work together to resist the flow of coolant diverting it away from where it is needed the most to cooler less resistive pathways where it is needed the least. In other words given the choice via randomized coolant pathways the reactor coolant will take the path of least resistance, and hot zones offer the highest resistance. Having identified the relationship between randomized coolant channel pathways and localized fuel melting it is now safe to assume that other reactor concepts that utilize randomized coolant pathways such as the foam core reactor are also susceptible to this phenomenon.

  5. An experimental study of the effect of collision properties on spout fluidized bed dynamics

    NARCIS (Netherlands)

    Buijtenen, van Maureen S.; Börner, Matthias; Deen, Niels G.; Heinrich, Stefan; Antonyuk, Sergiy; Kuipers, J.A.M.

    2009-01-01

    In this paper we experimentally study the effect of collision properties of different particle systems on the bed dynamics of a spout fluidized bed. This is done in different flow regimes: the spout-fluidization regime (case A), the jet-in-fluidized-bed regime (case B) and the spouting-with-aeration

  6. Effect of ramp length and slope on the efficacy of a baffled fish pass.

    Science.gov (United States)

    Baker, C F

    2014-02-01

    This study evaluated the effect of ramp length and slope on fish passage over baffled ramps with 15° and 30° gradients. Three fish species indigenous to New Zealand were tested: the redfin bully Gobiomorphus huttoni, the common bully Gobiomorphus cotidianus and the inanga Galaxias maculatus with ramp lengths of 3, 4·5 and 6 m. As slope and ramp length increased, passage success rate decreased for G. maculatus and G. cotidianus. At a slope of 15°, both G. maculatus and G. cotidianus could pass all ramp lengths tested with the highest success rate on the 3 m ramp. As the gradient increased to 30°, G. maculatus could only pass the 3 m ramp, and G. cotidianus were incapable of passing any ramp. Gobiomorphus huttoni were the only test species capable of climbing the wetted margin of the ramps. Increasing ramp slope significantly reduced passage success for G. huttoni, but ramp length, up to the maximum used in this study, had no significant influence on successful passage. PMID:24417428

  7. THE EFFECTS OF MODIFIED POSTERIOR TIBIAL SLOPE ON ACL STRAIN AND KNEE KINEMATICS: A HUMAN CADAVERIC STUDY

    OpenAIRE

    Fening, Stephen D.; Kovacic, Jeffrey; Kambic, Helen; McLean, Scott; Scott, Jacob; Miniaci, Anthony

    2008-01-01

    Increases to the posterior tibial slope can lead to an anterior shift in tibial resting position. However, the effect of this shift on anterior cruciate ligament (ACL) strain has not been investigated sufficiently. This study examined the relationship between increased tibial slope and ACL strain, as well as the subsequent kinematics of the tibiofemoral joint. We hypothesized increases in slope would shift the tibia anterior relative to the femur and increase ACL strain. ACL strain measuremen...

  8. Thermofluid effect on energy storage in fluidized bed reactor

    Science.gov (United States)

    Mahfoudi, Nadjiba; El Ganaoui, Mohammed; Moummi, Abdelhafid

    2016-05-01

    The development of innovative systems of heat storage is imperative to improve the efficiency of the existing systems used in the thermal solar energy applications. Several techniques were developed and realized in this context. The technology of the sand fluidized bed (sandTES) offers a promising alternative to the current state-of-the-art of the heat storage systems, such as fixed bed using a storage materials, as sand, ceramic, and stones, etc. Indeed, the use of the fluidization technique allows an effective heat transfer to the solid particles. With the sand, an important capacity of storage is obtained by an economic and ecological material [N. Mahfoudi, A. Moummi, M. El Ganaoui, Appl. Mech. Mater. 621, 214 (2014); N. Mahfoudi, A. Khachkouch, A. Moummi B. Benhaoua, M. El Ganaoui, Mech. Ind. 16, 411 (2015); N. Mahfoudi, A. Moummi, M. El Ganaoui, F. Mnasri, K.M. Aboudou, 3e Colloque internationale Francophone d"énergétique et mécanique, Comores, 2014, p. 91]. This paper presents a CFD simulation of the hydrodynamics and the thermal transient behavior of a fluidized bed reactor of sand, to determine the characteristics of storage. The simulation shows a symmetry breaking that occurs and gave way to chaotic transient generation of bubble formation after 3 s. Furthermore, the predicted average temperature of the solid phase (sand) increases gradually versus the time with a gain of 1 °C in an interval of 10 s. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  9. Comparative Study of Guizhou Sloping Land Soil and Water Conservation Effect of the Three Cropping Patterns

    OpenAIRE

    Chen, Zhenggang; Xiong, Yanhua; Li, Jian; Zhu, Qing

    2013-01-01

    Surface cover degree, monthly variation of topsoil water content, loss of soil and nutrient in alfalfa-corn intercropping, strip rotation cropping and corn monoculture were studied in this paper. Then soil and water conservation effect of these planting modes were compared. Results showed that surface cover degree was high during the all rainy season in both alfalfa-corn intercropping and strip rotation cropping mode, with slope field covered by vegetation all the year round. Roots of alfalfa...

  10. Fluidized bed roasting of molybdenite-effect of operating variables

    Energy Technology Data Exchange (ETDEWEB)

    Doheim, M.A.; Abdel-Wahab, M.Z.; Rassoul, S.A.

    1976-09-01

    The results of an investigation on the fluidized bed roasting of molybdenite are reported. Molybdenite mixed with quartz was subjected to an oxidizing roast in a 22 mm diam stainless steel batch fluidized bed reactor. Enriched air (with O/sub 2/) or diluted air (with N/sub 2/) was used as the fluidizing and oxidizing gas. In addition to the MoS/sub 2/ content of the solids and the O/sub 2/ content of the gas, the effect of temperature and flow rate was also examined. For the range of variables investigated, it was found that the temperature influences the rate of the roasting reaction greatly. The gas flow rate affects the conversion favorably up to a certain fluidizing flow rate. An increase in the O/sub 2/ content of the gas and the MoS/sub 2/ of the solids results in higher conversion levels. The unreacted core kinetic model was applied to the results; and the energy of activation for the reaction was obtained from the Arrhenius plot as 31,100 cal/gmol of MoS/sub 2/. The data obtained should be useful in the design and operation of larger scale roasting reactors.

  11. Fluidized bed roasting of molybdenite-effect of operating variables

    International Nuclear Information System (INIS)

    The results of an investigation on the fluidized bed roasting of molybdenite are reported. Molybdenite mixed with quartz was subjected to an oxidizing roast in a 22 mm diam stainless steel batch fluidized bed reactor. Enriched air (with O2) or diluted air (with N2) was used as the fluidizing and oxidizing gas. In addition to the MoS2 content of the solids and the O2 content of the gas, the effect of temperature and flow rate was also examined. For the range of variables investigated, it was found that the temperature influences the rate of the roasting reaction greatly. The gas flow rate affects the conversion favorably up to a certain fluidizing flow rate. An increase in the O2 content of the gas and the MoS2 of the solids results in higher conversion levels. The unreacted core kinetic model was applied to the results; and the energy of activation for the reaction was obtained from the Arrhenius plot as 31,100 cal/gmol of MoS2. The data obtained should be useful in the design and operation of larger scale roasting reactors

  12. Effects of slope plate variable and reheating on semi-solid structure of ductile cast iron

    Institute of Scientific and Technical Information of China (English)

    M. Nili-Ahmadabadi; F. Pahlevani; P. Babaghorbani

    2008-01-01

    Semi-solid metal casting and forming are known as a promising process for a wide range of metal alloys production. In spite of growing application of semi-solid processed light alloys, a few works have been reported about semi-solid processing of iron and steel. In this research inclined plate was used to change dendritic structure of iron to globular one. The effects of length and slope of plate on the casting structure were examined. The results show that the process can effectively change the dendritic structure to globular. In the slope plate angle of 7.5°and length of 560 mm with cooling rate of 67K·s-1 the optimum nodular graphite and solid globular particle were achieved.The results also show that by using slope plate inoculant fading can be prevented more easily since the total time of process is rather short.In addition, the semi-solid ductile cast iron prepared by inclined plate method, was reheated to examine the effect of reheating conditions on the microstructure and coarsening kinetics of the alloy. Solid fraction at different reheating temperatures and holding time was obtained and based on these results the optimum reheating temperature range was determined.

  13. Neutron-proton effective mass splitting in terms of symmetry energy and its density slope

    International Nuclear Information System (INIS)

    Using a simple density-dependent finite-range effective interaction having Yukawa form, the density dependence of isoscalar and isovector effective masses is studied. The isovector effective mass is found to be different for different pairs of like and unlike nucleons. Using HVH theorem, the neutron-proton effective mass splitting is represented in terms of symmetry energy and its density slope. It is again observed that the neutron-proton effective mass splitting has got a positive value when isoscalar effective mass is greater than the isovector effective mass and has a negative value for the opposite case. Furthermore, the neutron-proton effective mass splitting is found to have a linear dependence on asymmetry β. The second-order symmetry potential has a vital role in the determination of density slope of symmetry energy but it does not have any contribution on neutron-proton effective mass splitting. The finite-range effective interaction is compared with the SLy2, SKM, f−, f0, and f+ forms of interactions

  14. The Effects of Agitated Beds Homogenization on Stirrer Geometry and Bed Depth via DEM

    OpenAIRE

    Kohout, M.

    2014-01-01

    In this contribution open source DEM particle simulation software LIGGGHTS was studied and tested. Collision forces are there modelled by the softsphere approach with the Hertzian collision model. As an application we studied agitated particle beds (packed from glass spherical particles of two colours – packed vertically and horizontally) mixed by different types of agitators. Dependence of degree of homogenization on particle diameter, particle properties (Young’s modulus), and on geometric...

  15. Effective Heat Transfer Parameters In Beds Packed with Spherical Particles

    International Nuclear Information System (INIS)

    Effective radial thermal conductivity and wall heat transfer coefficient for packed bed of non reacted material, 4.8 mm alumina spheres, were experimentally determined at high temperatures up to 850 degree C for flow rates giving particle Reynolds numbers in the range of 10 - 220. Radial temperature profiles were measured at various axial positions. The results were analysed on the basis of a two-dimensional pseudo homogeneous non-plug flow model, where velocity profile take into account. Over these ranges both parameters, λer and αw, showed significant dependence on gas flow rates for all different wall temperatures and these dependencies were predicted well by correlations with particle Reynolds number

  16. Green roof stormwater retention: effects of roof surface, slope, and media depth.

    Science.gov (United States)

    VanWoert, Nicholaus D; Rowe, D Bradley; Andresen, Jeffrey A; Rugh, Clayton L; Fernandez, R Thomas; Xiao, Lan

    2005-01-01

    Urban areas generate considerably more stormwater runoff than natural areas of the same size due to a greater percentage of impervious surfaces that impede water infiltration. Roof surfaces account for a large portion of this impervious cover. Establishing vegetation on rooftops, known as green roofs, is one method of recovering lost green space that can aid in mitigating stormwater runoff. Two studies were performed using several roof platforms to quantify the effects of various treatments on stormwater retention. The first study used three different roof surface treatments to quantify differences in stormwater retention of a standard commercial roof with gravel ballast, an extensive green roof system without vegetation, and a typical extensive green roof with vegetation. Overall, mean percent rainfall retention ranged from 48.7% (gravel) to 82.8% (vegetated). The second study tested the influence of roof slope (2 and 6.5%) and green roof media depth (2.5, 4.0, and 6.0 cm) on stormwater retention. For all combined rain events, platforms at 2% slope with a 4-cm media depth had the greatest mean retention, 87%, although the difference from the other treatments was minimal. The combination of reduced slope and deeper media clearly reduced the total quantity of runoff. For both studies, vegetated green roof systems not only reduced the amount of stormwater runoff, they also extended its duration over a period of time beyond the actual rain event. PMID:15888889

  17. Is bed rest an effective treatment modality for pressure ulcers?

    Science.gov (United States)

    Norton, Linda; Sibbald, R Gary

    2004-10-01

    Despite the well-documented medical, physical, and psychological complications associated with this care management option, bed rest remains a frequently prescribed treatment modality for conditions such as pressure ulcers. Cognitive and psychosocial complications of bed rest include depression, learned helplessness, perceptual changes, and fatigue. Physically, complications can include contractures, muscle atrophy, osteoporosis, pathologic fractures, urinary tract infections, decreased cardiac reserve, decreased stroke volume, resting and post-exercise tachycardia, orthostatic hypotension, pulmonary embolism, deep venous thrombosis, pneumonia, anorexia, constipation, and bowel impaction. Furthermore, the literature does not contain evidence supporting the use of bed rest to facilitate healing of pressure ulcers. More suitable approaches to pressure ulcer care include limiting bed rest, initiating occupational therapy, integrating meaningful tasks into daily activities, increasing outside stimulation, involving patients in care decisions and addressing their concerns, optimizing nutritional status, and managing pressure and shear throughout daily activities. Recommendations for implementing alternatives to bed rest are addressed. PMID:15509881

  18. Effects of light polarization and waves slope statistics on the reflectance factor of the sea surface.

    Science.gov (United States)

    D'Alimonte, Davide; Kajiyama, Tamito

    2016-04-18

    Above-water radiometry depends on estimates of the reflectance factor ρ of the sea surface to compute the in situ water-leaving radiance. The Monte Carlo code for ocean color simulations MOX is used in this study to analyze the effect of different environmental components on ρ values. A first aspect is examining the reflectance factor without and by accounting for the sky-radiance polarization. The influence of the sea-surface statistics at discrete grid points is then considered by presenting a new scheme to define the variance of the waves slope. Results at different sun elevations and sensor orientations indicate that the light polarization effect on ρ simulations reduces from ∼17 to ∼10% when the wind speed increases from 0 to 14m s-1. An opposite tendency characterizes the modeling of the sea-surface slope variance, with ρ differences up to ∼12% at a wind speed of 10m s-1. The joint effect of polarization and the the sea-surface statistics displays a less systematic dependence on the wind speed, with differences in the range ∼13 to ∼18%. The ρ changes due to the light polarization and the variance of the waves slope become more relevant at sky-viewing geometries respectively lower and higher than 40° with respect to the zenith. An overall compensation of positive and negative offsets due to light polarization is finally documented when considering different sun elevations. These results address additional investigations which, by combining the modeling and experimental components of marine optics, better evaluate specific measurement protocols for collecting above-water radiometric data in the field. PMID:27137234

  19. Effectiveness of fluidized pellet bed for removing soluble contaminants

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaochang; LI Zhihua; WANG Zhen; LI Jinrong; LI Jiayu; CHEN Rong

    2009-01-01

    Fluidized pellet bed (FPB) has been successfully applied in water and wastewater treatment. However, the removal mechanism of contaminants especially the soluble ones, is still unclear. This study aimed to evaluate the effectiveness of FPB reactor for removing soluble contaminants from synthetic wastewater. By only coagulation through jar test operation with addition of polyaluminium chloride (PACl) as primary coagulant and polyacryamide (PAM) as coagulant-aid, the removals of soluble chemical oxygen demand (COD), suspended solids (SS), total phosphorus (TP), and NH4+-N were found to be only 2.2%--7.5%, 5.7%--25.5%, and 9.9%--18.5%, respectively. However, by FPB operation under the same dosage of coagulants, these values increased to 82.7%, 37.2%, and 50%, indicating that the formation of pellets in the FPB effectively enhanced the removal of soluble contaminants. By careful comparison of the settleablility and filterability of the pollutants after coagulation, the originally soluble contaminants could be divided into three groups, namely: (i) coagulated-and-settleable, (ii) coagulated-but-nonsettleable, and (iii) uncoagulable. It was found that not only the first two groups but also a large part of the third group could be effectively removed by FPB operation. However, the mechanism for the removal of the uncoagulable pollutants by FPB operation still needs further investigation.

  20. Rainfall infiltration on hilly slopes under various lithology and its effect on tree growth in the dry-hot valley

    Institute of Scientific and Technical Information of China (English)

    YANG; Zhong; XIONG; Donghong; ZHOU; Hongyi; ZHANG; Xinbao

    2003-01-01

    Revegetation is very difficult in dry-hot valleys in China. Rainfall infiltration capability on hilly slopes is one of the key factors determining soil moisture conditions and tree growth in the dry-hot valley. Low rainfall infiltration often results in soil drought on slopes under the dry-hot valleys climate. Rainfall infiltration capability varies greatly with the difference of slope lithologic porosity. The infiltration rates of five lithologic slope-types, Schist Slope, Grit Slope, Gravel Slope, the slightly eroded Mudstone Slope and the intensively eroded Mudstone Slope, are 1.40-8.67, 6.33, 0.69-2.20, 0.6-1.3 and 0.03-0.63 mm/min, respectively. With its viscid compact soil body and low infiltration capability which causes little infiltrating rainfall, mudstone slope can afford little effective supply to soil water and leads to serious drought of soil in dry seasons, resulting in cessation of growth or even wide-spread death of trees due to physiological damage for the excessive deficit of water in dry season and also the low productivity of stands. Hence, it is extremely difficult to restore vegetation on this type of slope. The other four lithologic slope-types, however, with well-developed soil crevice, high infiltration capability and thus more infiltrating rainfall, can afford more available soil water supply and the trees on them can obtain better growth and relatively higher productivity, compared with those on Mudstone Slope. Revegetation in dry-hot valleys is controlled by the soil moisture conditions of different slope-types, and it can be implemented by relying on the dominative life-form plant species, the suitable spatial arrangement of different life-forms of arbor-shrub-herb species, and the establishment of ecological community relationship between vegetation and soil moisture in habits. On the other hand, ground making measures for forestation and the runoff-collecting engineering measures to increase the rainfall infiltration are the major

  1. Slope filtrations

    OpenAIRE

    André, Yves

    2008-01-01

    Many slope filtrations occur in algebraic geometry, asymptotic analysis, ramification theory, p-adic theories, geometry of numbers... These functorial filtrations, which are indexed by rational (or sometimes real) numbers, have a lot of common properties. We propose a unified abstract treatment of slope filtrations, and survey how new ties between different domains have been woven by dint of deep correspondences between different concrete slope filtrations.

  2. NUMERICAL STUDY ON EFFECT OF WAVING BED ON THE SURFACE WAVE

    Institute of Scientific and Technical Information of China (English)

    WU Zheng-ren; CHENG You-liang; WANG Song-ling

    2006-01-01

    The effect of the waving bed on the surface wave was investigated. The wave equation was reduced from the potential flow theory with the perturbation technique, and then was solved by using the pseudo-spectral method. The waterfall of the surface wave was simulated with the Matlab. It is shown that for the waving bed, an additional harmonic wave appears on the surface together with the solitary wave existing for the non-waving bed, and two kinds of waves do not interfere with each other. With the development of time, the waveform for the waving bed is kept invariable, and just the amplitude is reduced gradually. Wave-breaking phenomenon for the non-waving bed does not appear, so the waving bed seems useful to prevent the breaking of the wave.

  3. Use of Structure-from-Motion Photogrammetry Technique to model Danxia red bed landform slope stability by discrete element modeling - case study at Mt. Langshan, Hunan Province, China

    Science.gov (United States)

    Simonson, Scott; Hua, Peng; Luobin, Yan; Zhi, Chen

    2016-04-01

    Important to the evolution of Danxia landforms is how the rock cliffs are in large part shaped by rock collapse events, ranging from small break offs to large collapses. Quantitative research of Danxia landform evolution is still relatively young. In 2013-2014, Chinese and Slovak researchers conducted joint research to measure deformation of two large rock walls. In situ measurements of one rock wall found it to be stable, and Ps-InSAR measurements of the other were too few to be validated. Research conducted this year by Chinese researchers modeled the stress states of a stone pillar at Mt. Langshan, in Hunan Province, that toppled over in 2009. The model was able to demonstrate how stress states within the pillar changed as the soft basal layer retreated, but was not able to show the stress states at the point of complete collapse. According to field observations, the back side of the pillar fell away from the entire cliff mass before the complete collapse, and no models have been able to demonstrate the mechanisms behind this behavior. A further understanding of the mechanisms controlling rockfall events in Danxia landforms is extremely important because these stunning sceneries draw millions of tourists each year. Protecting the tourists and the infrastructure constructed to accommodate tourism is of utmost concern. This research will employ a UAV to as universally as possible photograph a stone pillar at Mt. Langshan that stands next to where the stone pillar collapsed in 2009. Using the recently developed structure-from-motion technique, a 3D model of the pillar will be constructed in order to extract geometrical data of the entire slope and its structural fabric. Also in situ measurements will be taken of the slope's toe during the field work exercises. These data are essential to constructing a realistic discrete element model using the 3DEC code and perform a kinematic analysis of the rock mass. Intact rock behavior will be based on the Mohr Coulomb

  4. Effect of different bedding materials on the reproductive performance of mice

    Directory of Open Access Journals (Sweden)

    F.J. Potgieter

    1997-07-01

    Full Text Available Vermiculite, pine shavings and unbleached eucalyptus pulp contact-bedding were compared using the number of litters and individuals born and weaned, mortality rates at different stages of the lactation period, and the weight increase of pups as evaluation indices for bedding quality. These bedding materials exerted different effects on the reproductive performance of the same mouse strain. The same is true for the effect of a specific bedding material on different mouse strains. These effects are most pronounced during the first 4 days of life. As a whole, the results demonstrated that eucalyptus pulp was the better bedding type, followed by pine shavings and vermiculite. The latter material had a detri-mental effect on the mating success of AKR mice.

  5. An integrated methodology to evaluate the effects of plants for slope stability

    Science.gov (United States)

    Dani, A.; Giadrossich, F.; Guastini, E.; Preti, F.; Togni, M.; Vannocci, P.

    2009-04-01

    The topic of eco-hydrological dynamics is fundamental in slope stability analysis on vegetated soils. The understanding of hydrological processes are based on the knowledge of the geotechnical properties of soils, on the pedological, pluviometrical and vegetational features and they are all related to the soil and roots interaction. To quantify the stability slopes effects that the root systems provide to the soil, it is important to know their spatial distribution and their tensile strength. Because of the difficulty to estimate the action of single roots, in the stability evaluation of vegetated hillslopes, only the additional root cohesion is generally taken into account depending on the spatial variability of the root area ratio RAR (the ratio between the area occupied by roots in a unit area of soil) distribution (especially with depth), even if it is not sure that all the roots in the soil actually mobilise their whole tensile strength (e.g. each root could not break at the same time due to different tortuosity and elasticity). In this paper we test some analysis and methodologies: • to value the stress-strain curve and ultimate tensile strength of the roots, we use two different testing machines normally employed for wood rheological behavior studies. • to value the cohesion contribution to rooted soil samples we use a geotechnical apparatus (the Casagrande direct shear test); • an indirect methodology to obtain the measurement of the fundamental parameters of the root apparatus; • an indirect methodology to estimate the analytical descriptors of the root apparatus based on climatic and pedological features; • a GIS survey to estimate the stability factor and its evolution with some models in different vegetation management. Mediterranean environments, particularly, where soils are shallow and water is scarce over the growing season (water controlled ecosystems), it would be more economical for plants to have the roots closer to the soil surface

  6. Summer Monsoon and Annual Variability of Sea Surface Slope and Their Effects on Alongshore Current near Qingdao

    Institute of Scientific and Technical Information of China (English)

    蒲书箴; 程军; 张义钧; 石强; 骆敬新; 范文静

    2004-01-01

    Based on the monthly mean sea level data obtained from 3 years′ (1999-2001) tide-gauge measurements, the annual variability of the sea level near Qingdao and Jiaozhou Bay is studied and discussed in this paper. Results show that the sea surface height at all the tide gauges becomes higher in summer than that in winter,with an obvious seasonal variability.Furthermore the sea surface height measured at a short distance outside the bay is lower than that in thebay, showing a sea surface slope downward from north to south. The reasons for the formation of the slope are explained as well, The dynamic action ofthe summer monsoon and the sea surface slope, and their effects on the monthly mean current are studied by means of dynamics principles. The importance of the summer monsoon and the pressure gradient generated by the sea surface slope, with their effects on the alongshore current, is pointed out and emphasized in this paper.

  7. The effect of lateral flooding on the coolability of irregular core debris beds

    Energy Technology Data Exchange (ETDEWEB)

    Takasuo, Eveliina, E-mail: eveliina.takasuo@vtt.f [VTT Technical Research Centre of Finland (Finland); Holmstroem, Stefan; Kinnunen, Tuomo; Pankakoski, Pekka H.; Hosio, Ensio; Lindholm, Ilona [VTT Technical Research Centre of Finland (Finland)

    2011-04-15

    The coolability of ex-vessel core debris is an important issue in the severe accident management strategy of, e.g. the Nordic boiling water reactors. In a core melt accident, the molten core material is expected to discharge into the containment and form a porous debris bed on the pedestal floor of a flooded lower drywell. The debris bed generates decay heat which must be removed by boiling in order to stabilize the debris bed and to prevent local dryout and possible re-melting of the material. The STYX test facility which consists of a cylindrical bed of irregular alumina particles has been used to investigate the effect of lateral coolant inflow on the dryout heat flux of the particle bed. The lateral flow was achieved by downcomers attached on the sides of the test rig. The downcomers provide coolant into the lower region of the bed by natural circulation. Both homogenous and stratified bed configurations have been examined. It was observed that the dryout heat flux is increased by 22-25% for the homogenous test bed compared to the case with no lateral flooding. For the stratified configuration with a fine particle layer on top of the bed, no significant increase in the dryout heat flux was observed. The experiments have been analyzed by using the MEWA-2D code. Models which include explicit consideration of gas-liquid friction were used in the calculations in order to realistically capture the lateral flow configuration.

  8. The effect of lateral flooding on the coolability of irregular core debris beds

    International Nuclear Information System (INIS)

    The coolability of ex-vessel core debris is an important issue in the severe accident management strategy of, e.g. the Nordic boiling water reactors. In a core melt accident, the molten core material is expected to discharge into the containment and form a porous debris bed on the pedestal floor of a flooded lower drywell. The debris bed generates decay heat which must be removed by boiling in order to stabilize the debris bed and to prevent local dryout and possible re-melting of the material. The STYX test facility which consists of a cylindrical bed of irregular alumina particles has been used to investigate the effect of lateral coolant inflow on the dryout heat flux of the particle bed. The lateral flow was achieved by downcomers attached on the sides of the test rig. The downcomers provide coolant into the lower region of the bed by natural circulation. Both homogenous and stratified bed configurations have been examined. It was observed that the dryout heat flux is increased by 22-25% for the homogenous test bed compared to the case with no lateral flooding. For the stratified configuration with a fine particle layer on top of the bed, no significant increase in the dryout heat flux was observed. The experiments have been analyzed by using the MEWA-2D code. Models which include explicit consideration of gas-liquid friction were used in the calculations in order to realistically capture the lateral flow configuration.

  9. Hyperbolic Mild Slope Equations with Inclusion of Amplitude Dispersion Effect: Random Waves

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    New hyperbolic mild slope equations for random waves are developed with the inclusion of amplitude dispersion. The frequency perturbation around the peak frequency of random waves is adopted to extend the equations for regular waves to random waves. The nonlinear effect of amplitude dispersion is incorporated approximately into the model by only considering the nonlinear effect on the carrier waves of random waves, which is done by introducing a representative wave amplitude for the carrier waves. The computation time is greatly saved by the introduction of the representative wave amplitude. The extension of the present model to breaking waves is also considered in order to apply the new equations to surf zone. The model is validated for random waves propagate over a shoal and in surf zone against measurements.

  10. Effect of Slope Position on Soil Properties and Types Along an Elevation Gradient of Arasbaran Forest, Iran

    Directory of Open Access Journals (Sweden)

    Hossein Rezaei

    2015-01-01

    Full Text Available Sustainable development by forest managing need to identify forest ecosystem elements. Forest soil is the most important element of forest ecosystem that has key roles in forest managing. Therefore, studying of soil properties and evolution under different environmental conditions is necessary for sustainable management of forest ecosystems. Spatial variation of soil properties is significantly influenced by some environmental factors that slope position is one of them. The aim of this study was evaluating effects of slope position on forest soil change which was carried out in Arasbaran forest, North-West of Iran. Nine soil profiles were dug, described and sampled in three different parts of an altitudinal transect with same environmental conditions and different slope positions. Then soil samples were analysed physicaly and chemicaly and so classified based on Soil Taxonomy 2014. Also according to obtained results One-way analysis of variance was used to test relations of soil properties and slope positions. This results revealed significant effect of slope positions on thickness of the soil profile and solum, clay, organic carbon and total nitrogen percentages and cation exchange capacity at 5% level of confidence which lead to change of type, depth and sequence of soil horizons along altitudinal transect. Finally, it has found that slope position not only has important role in soil properties changes and soil evolution but also it can't be refused the various role and influence of same forest stand in different slope positions. Therefore various soils such as Inceptisols, Alfisols and Molisols were observed under different slope positions. Then it can be achieved that, because of special forest vegetation, soil evolution along altitudinal transect of forest ecosystems are differing from other ecosystems. Thus, for forest soil management program it is necessary to consider both of topography and vegetation effect over the area, even if one of

  11. The effect of climbing ability and slope inclination on vertical foot loading using a novel force sensor instrumentation system.

    Science.gov (United States)

    Baláš, Jiří; Panáčková, Michaela; Jandová, Soňa; Martin, Andrew J; Strejcová, Barbora; Vomáčko, Ladislav; Charousek, Jan; Cochrane, Darryl J; Hamlin, Mike; Draper, Nick

    2014-12-01

    The aim of the study was to assess the effects of climbing ability and slope inclination on vertical loading both in terms the forces involved and physiological responses. Five novice and six intermediate female climbers completed a climbing route at three slope inclinations (85°, 90°, and 98°). The vertical loading during the climb was assessed by force-time integral using a Novel Pedar-X insole and physiological responses via oxygen uptake and heart rate. The novice climbers had a significantly lower (p vertical loading on foot holds and higher oxygen uptake and heart rate compared to intermediate climbers. A significant negative correlation was identified between the force-time integral and oxygen uptake (R = -0.72), and with heart rate (R = -0.64), respectively. The time-force integral decreased across the ascents with increasing slope inclination (p rate) across all slope inclinations. PMID:25713667

  12. Effect and surfactants on three-phase fluidized bed hydrodynamics

    International Nuclear Information System (INIS)

    Experiments were conducted to discern the relationship between three-phase fluidized bed hydrodynamics and surfactant solution characteristics. The standard characteristic, equilibrium surface tension, is inadequate. A novel method for surface tension evaluation, a dynamic maximum bubble pressure technique, was found to differentiate the 12 different solutions studied. The surfactant solutions were categorized based upon a combination of the terminal bubble rise velocity reduction, the equilibrium surface tension, and the new bubble tension values. These surfactant solution categories were correlated with experimentally observed three-phase fluidized bed and bubble column hydrodynamic behavior. Specifically, empirical correlations for gas holdup are presented

  13. Effects of Rainfall Intensity and Slope Gradient on Runoff and Soil Moisture Content on Different Growing Stages of Spring Maize

    Directory of Open Access Journals (Sweden)

    Wenbin Mu

    2015-06-01

    Full Text Available The rainfall-runoff process (RRP is an important part of hydrologic process. There is an effective measure to study RRP through artificial rainfall simulation. This paper describes a study on three growing stages (jointing stage, tasseling stage, and mature stage of spring maize in which simulated rainfall events were used to study the effects of various factors (rainfall intensity and slope gradient on the RRP. The RRP was tested with three different rainfall intensities (0.67, 1.00, and 1.67 mm/min and subjected to three different slopes (5°, 15°, and 20° so as to study RRP characteristics in semiarid regions. Regression analysis was used to study the results of this test. The following key results were obtained: (1 With the increase in rainfall intensity and slope, the increasing relationship with rainfall duration, overland flow, and cumulative runoff, respectively, complied with logarithmic and quadratic functions before reaching stable runoff in each growing stage of spring maize; (2 The runoff coefficient increased with the increase in rainfall intensity and slope in each growing stages of spring maize. The relationship between runoff coefficient, slope, rainfall intensity, rainfall duration, antecedent soil moisture, and vegetation coverage was multivariate and nonlinear; (3 The runoff lag time decreased with the increase in rainfall intensity and slope within the same growing stage. In addition, the relationship between runoff lag time, slope, rainfall intensity, antecedent soil moisture, and vegetation coverage could also be expressed by a multivariate nonlinear equation; (4 The descent rate of soil infiltration rate curve increased with the increased rainfall intensity and slope in the same growing stage. Furthermore, by comparing the Kostiakov, Horton, and Philip models, it was found that the Horton infiltration model was the best for estimating soil infiltration rate and cumulative infiltration under the condition of test.

  14. Slope Gradient and Vegetation Cover Effects on The Runoff and Sediment Yield in Hillslope Agriculture

    OpenAIRE

    Obaid ur Rehman; Muhammad Rashid; Rahina Kausar; Sarosh Alvi; Riaz Hussain

    2015-01-01

    Cultivation of field crops is a challenge and risky business in sloping areas. A study was conducted as a demonstration model for the sloppy lands of Fateh Jang, Pakistan. The objectives of this study were to monitor the runoff water and soil sediment loss under different vegetative covers and slope gradients in comparison with bare fallow on each slope gradient. Three artificial slope gradients i.e., 1%, 5% and 10% were established and three crops i.e., Wheat, Gram and Lentil were cultivated...

  15. Effects of basin bottom slope on jet hydrodynamics and river mouth bar formation

    Science.gov (United States)

    Jiménez-Robles, A. M.; Ortega-Sánchez, M.; Losada, M. A.

    2016-06-01

    River mouth bars are strategic morphological units primarily responsible for the development of entire deltaic systems. This paper addresses the role of receiving basin slope in the hydrodynamics of an exiting sediment-laden turbulent jet and in resulting mouth bar morphodynamics. We use Delft3D, a coupled hydrodynamic and morphodynamic numerical model, along with a theoretical formulation to reproduce the physics of the problem, characterized by a fluvially dominated inlet free of waves and tides. We propose an updated theoretical model with a slope-dependent entrainment coefficient, showing that the rate at which ambient fluid is incorporated into a jet increases with higher basin slopes. Transient results reveal that the magnitude of a basin slope can alter the stability of a jet, favoring the formation of an unstable meandering jet. While a stable jet gives rise to "middle-ground" bars accompanied by diverging channels, a "lunate" mouth bar results from unstable jets. Additional morphodynamic simulations demonstrate that the time required for mouth bar stagnation in its final position increases linearly with the basin slope. In contrast, the distance at which the mouth bar eventually forms decreases until reaching an asymptotic value for slopes higher than 2%. Moreover, the basin slope highly influences sedimentary processes responsible for bar formation: for milder slopes, progradation processes prevail, while in steeper basins aggradation is more relevant. Finally, the minimum relative water depth over a bar crest that forces the flow to bifurcate around a fully developed bar decreases with the basin slope.

  16. The feedback effect caused by bed load on a turbulent liquid flow

    CERN Document Server

    Franklin, Erick de Moraes; Rosa, Eugênio Spanó

    2016-01-01

    Experiments on the effects due solely to a mobile granular layer on a liquid flow are presented (feedback effect). Nonintrusive measurements were performed in a closed conduit channel of rectangular cross section where grains were transported as bed load by a turbulent water flow. The water velocity profiles were measured over fixed and mobile granular beds of same granulometry by Particle Image Velocimetry. The spatial resolution of the measurements allowed the experimental quantification of the feedback effect. The present findings are of importance for predicting the bed-load transport rate and the pressure drop in activities related to the conveyance of grains.

  17. The effects of rehabilitation on the muscles of the trunk following prolonged bed rest

    OpenAIRE

    Hides, Julie A.; Lambrecht, Gunda; Richardson, Carolyn A.; Stanton, Warren R.; Armbrecht, Gabriele; Pruett, Casey; Damann, Volker; Felsenberg, Dieter; Belavý, Daniel L.

    2010-01-01

    Microgravity and inactivity due to prolonged bed rest have been shown to result in atrophy of spinal extensor muscles such as the multifidus, and either no atrophy or hypertrophy of flexor muscles such as the abdominal group and psoas muscle. These effects are long-lasting after bed rest and the potential effects of rehabilitation are unknown. This two-group intervention study aimed to investigate the effects of two rehabilitation programs on the recovery of lumbo-pelvic musculature following...

  18. Effect of seat and table top slope on the biomechanical stress sustained by the musculo-skeletal system.

    Science.gov (United States)

    Hamaoui, Alain; Hassaïne, Myriam; Watier, Bruno; Zanone, Pier-Giorgio

    2016-01-01

    The purpose of this study was to assess the effect of table and seat slope on the biomechanical stress sustained by the musculo-skeletal system. Angular position of the head and trunk, and surface electromyography of eleven postural muscles were recorded while seated under different conditions of seat slope (0°, 15° forward) and table slope (0°, 20° backward). The specific stress sustained by C7-T1 joint was estimated with isometric torque calculation. The results showed that the backward sloping table was associated with a reduction of neck flexion and neck extensors EMG, contrasting with a concurrent overactivity of the deltoideus. The forward sloping chair induced an anterior pelvic tilt, but also a higher activity of the knee (vasti) and ankle (soleus) extensors. It was concluded that sloping chairs and tables favor a more erect posture of the spine, but entails an undesirable overactivity of upper and lower limbs muscles to prevent the body from sliding. PMID:26669951

  19. Effect of forest vegetation on runoff and sediment production in sloping lands of Loess area

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaoming; YU Xinxiao; WU Sihong; WEI Tianxing; ZHANG Xuepei

    2006-01-01

    According to fixed-position data for 1985-2003 from nine runoff plots of Caijiachuan watershed which lies in Jixian County of Shanxi Province in Loess area,this paper studied the relationship between vegetation and runoff and sediment production in sloping lands in detail,which helps to provide scientific basis for vegetation m-construction and studies on environmental transformation of water and sediment in watersheds of Loess area.Although,many study results testify that forest vegetation has an important function in soil and water conservation and cutting runoff,the effect of vegetation on runoff and sediment transmission is complicated,and this needs to be studied in depth.The results of the paper showed the following.Firstly,the natural secondary forest performs better function of soil and water conservation than artificial Robinia pseudoacacia forest,and runoff and sediment produced in the former in individual rainfall were 65%-82% and 23%-92% of those pro duced in the latter.At the same time,better correlative relationship between runoff and sediment production and rainfall and rainfall intensity were testified by multiple regression,but the correlation decreased gradually with the increase of canopy density of forest.Secondly,the difference of runoff and sediment production in several land use types was very distinct,and the amount of runoff and sediment produced from Ostryopsis davidiana forest and natural secondary forest were the least,and runoff and sediment produced from in artificial Robinia pseudoacacia forest and Pinus tabulaeformis forest were 5-fold as much as those from O.davidiana forest.Besides,runoff and sediment produced in mixed planting of apple trees and crops were 16.14-fold and 2.96-fold than those of O.davidiana forest,respectively,but the amount decreased obviously after high-standard soil preparation in the case of the former.Thirdly,based on gray cognate analyses of factors affecting runoff and sediment production in sloping land

  20. The effectiveness of dispersants on Alaska North Slope crude oil under various temperature and salinity regimes

    Energy Technology Data Exchange (ETDEWEB)

    Fingas, M.; Fieldhouse, B.; Wang, Z. [Environment Canada, Ottawa, ON (Canada). Emergencies Science and Technology Division, Environmental Technology Centre, Science and Technology Branch

    2006-07-01

    The results of a study investigating the influence of salinity and temperature interactions on dispersants were presented. Experiments were conducted on Alaska North Slope oil at lower temperatures and lower salinity in order to determine optimal dispersant application measurements. Dispersant was pre-mixed with oil and placed on water in a test vessel. The test vessel was agitated on a moving table shaker. At the end of the shaking period, a settling period was allowed and a sample of water was taken. The oil in the water column was extracted from the water using a pentane/dichloromethane mixture and analyzed using gas chromatography. A set of calibration samples was run concurrently with the test samples to establish a calibration curve. ASMB standard oil premixed with Corexit 9500 was tested for effectiveness at 3 temperatures and 8 salinities, including fresh water. Results indicated that the maximum effectiveness was obtained at a temperature of 10 degrees C and at a salinity of 25 per mil. It was noted that temperature and salinity effects are interrelated, with the salinity effect peaking at a select value depending on specific surfactant content. It was suggested that the match between ionic strength and its relation to the surfactant polarity may be the factor that causes the reversal of results. It was concluded that there is an interrelationship between temperature, salinity and the effectiveness of dispersants, indicating that a 3-way correlation may yield a predictive model with good reliability. 6 refs., 1 tab., 2 figs.

  1. Effects of the symmetry energy slope on the axial oscillations of neutron stars

    Institute of Scientific and Technical Information of China (English)

    Wen De-Hua; Zhou Ying

    2013-01-01

    The impact of symmetry energy slope L on the axial w-mode oscillations is explored,where the range of the constrained slope L of symmetry energy at saturation density is adopted from 25 MeV to 115 MeV while keeping the equation of state (EOS) of symmetric nuclear matter fixed.Based on the range of the symmetry energy slope,a constraint on the frequency and damping time of the wI-mode of the neutron star is given.It is found that there is a perfect linear relation between the frequency and the stellar mass for a fixed slope L,and the softer symmetry energy corresponds to a higher frequency.Moreover,it is confirmed that both the frequencies and damping times have a perfect universal scaling behavior for the EOSs with different symmetry energy slopes at saturation density.

  2. Internal-wave reflection from uniform slopes: higher harmonics and Coriolis effects

    Directory of Open Access Journals (Sweden)

    T. Gerkema

    2006-01-01

    Full Text Available Weakly nonlinear reflection of internal waves from uniform slopes produces higher harmonics and mean fields; the expressions are here derived for constant stratification and with Coriolis effects fully included, i.e. the horizontal component of the earth rotation vector (referred to as 'non-traditional'' is taken into account. Uniformity in one of the horizontal directions is assumed. It is shown that solutions can be as readily derived with as without ; hence there is no need to make the so-called Traditional Approximation. Examples of reflecting internal-wave beams are presented for super-inertial, inertial and sub-inertial frequencies. The problem of resonant and non-resonant forcing of the second harmonic is studied for single plane waves; unlike under the Traditional Approximation, the problem of reflection from a horizontal bottom no longer forms a singular case. Non-traditional effects are favourable to resonant forcing at near-tidal rather than near-inertial frequencies, and generally increase the intensity of the second harmonic. Strong stratification tends to suppress non-traditional effects, but a near-total suppression is only attained for high values of stratification that are characteristic of the seasonal thermocline; in most parts of the ocean, non-traditional effects can therefore be expected to be important.

  3. Success-slope effects on the illusion of control and on remembered success-frequency

    Directory of Open Access Journals (Sweden)

    Anastasia Ejova

    2013-07-01

    Full Text Available The illusion of control refers to the inference of action-outcome contingency in situations where outcomes are in fact random. The strength of this illusion has been found to be affected by whether the frequency of successes increases or decreases over repeated trials, in what can be termed a ``success-slope'' effect. Previous studies have generated inconsistent findings regarding the nature of this effect. In this paper we present an experiment (N = 334 that overcomes several methodological limitations within this literature, employing a wider range of dependent measures (measures of two different types of illusory control, primary (by self and secondary (by luck, as well as measures of remembered success-frequency. Results indicate that different dependent measures lead to different effects. On measures of (primary, but not secondary control over the task, scores were highest when the rate of success increased over time. Meanwhile, estimates of success-frequency in the task did not vary across conditions and showed trends consistent with the broader literature on human memory.

  4. Effectiveness of sloping agricultural land technology on soil fertility status of mid-hills in Nepal

    Institute of Scientific and Technical Information of China (English)

    Kiran Lamichhane

    2013-01-01

    Hedgerows with intercropping systems were established at the ICIMOD test and demonstration site at Godawari to assess the effective-ness of Sloping Agricultural Land Technology (SALT) in reducing run-off water volume, controlling soil loss, increasing crop production, and improving soil fertility in the mid-hills of Nepal. Runoff water volume (1996-2002), soil loss (1996-2002) and maize yield (1995-2001), and soil fertility-related parameters were assessed on SALT models with three factors:the type of nitrogen-fixing plant, the farmers’ practice, and fertilizer use. Results showed a significant effect of Alnus nepalensis and/or Indigofera dosua on runoff water volume, soil loss, crop produc-tion, soil water retention, and soil nutrients (NPK). Farmers’ practice and fertilization did not play a significant role in reducing runoff water and soil loss. However, farmers’ practice significantly increased crop produc-tion. Therefore, integrating soil conservation approaches on SALT sys-tems enhances stable economic output to hills and mountain farmers.

  5. Performance optimization of dense-array concentrator photovoltaic system considering effects of circumsolar radiation and slope error.

    Science.gov (United States)

    Wong, Chee-Woon; Chong, Kok-Keong; Tan, Ming-Hui

    2015-07-27

    This paper presents an approach to optimize the electrical performance of dense-array concentrator photovoltaic system comprised of non-imaging dish concentrator by considering the circumsolar radiation and slope error effects. Based on the simulated flux distribution, a systematic methodology to optimize the layout configuration of solar cells interconnection circuit in dense array concentrator photovoltaic module has been proposed by minimizing the current mismatch caused by non-uniformity of concentrated sunlight. An optimized layout of interconnection solar cells circuit with minimum electrical power loss of 6.5% can be achieved by minimizing the effects of both circumsolar radiation and slope error. PMID:26367685

  6. Pulling up the runaway: the effect of new evidence on euthanasia's slippery slope.

    OpenAIRE

    Ryan, C. J.

    1998-01-01

    The slippery slope argument has been the mainstay of many of those opposed to the legalisation of physician-assisted suicide and euthanasia. In this paper I re-examine the slippery slope in the light of two recent studies that examined the prevalence of medical decisions concerning the end of life in the Netherlands and in Australia. I argue that these two studies have robbed the slippery slope of the source of its power--its intuitive obviousness. Finally I propose that, contrary to the warn...

  7. An experimental study of the effect of collision properties on spout fluidized bed dynamics

    OpenAIRE

    Buijtenen, van, M.S.; Börner, Matthias; Deen, Niels G.; Heinrich, Stefan; Antonyuk, Sergiy; Kuipers, J.A.M.

    2009-01-01

    In this paper we experimentally study the effect of collision properties of different particle systems on the bed dynamics of a spout fluidized bed. This is done in different flow regimes: the spout-fluidization regime (case A), the jet-in-fluidized-bed regime (case B) and the spouting-with-aeration regime (case C). The considered particle systems comprise glass beads, γ-alumina oxide and zeolite 4A particles, which are all classified as Geldart D. A non-intrusive measurement technique is use...

  8. Exercise Effects on the Course of Gray Matter Changes Over 70 Days of Bed Rest

    Science.gov (United States)

    Koppelmans, V.; Ploutz-Snyder, L.; DeDios, Y. E.; Wood, S. J.; Reuter-Lorenz, P. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.; Seidler, R. D.

    2014-01-01

    Long duration spaceflight affects posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes through direct effects on peripheral changes that result from reduced vestibular stimulation and body unloading. Effects of microgravity on sensorimotor function have been investigated on earth using bed rest studies. Long duration bed rest serves as a space-flight analogue because it mimics microgravity in body unloading and bodily fluid shifts. It has been hypothesized that the cephalad fluid shift that has been observed in microgravity could potentially affect central nervous system function and structure, and thereby indirectly affect sensorimotor or cognitive functioning. Preliminary results of one of our ongoing studies indeed showed that 70 days of long duration head down-tilt bed rest results in focal changes in gray matter volume from pre-bed rest to various time points during bed rest. These gray matter changes that could reflect fluid shifts as well as neuroplasticity were related to decrements in motor skills such as maintenance of equilibrium. In consideration of the health and performance of crewmembers both inand post-flight we are currently conducting a study that investigates the potential preventive effects of exercise on gray matter and motor performance changes that we observed over the course of bed rest. Numerous studies have shown beneficial effects of aerobic exercise on brain structure and cognitive performance in healthy and demented subjects over a large age range. We therefore hypothesized that an exercise intervention in bed rest could potentially mitigate or prevent the effects of bed rest on the central nervous system. Here we present preliminary outcomes of our study.

  9. Beyond the bed: Effects of metal contamination on recruitment to bedded sediments and overlying substrata

    International Nuclear Information System (INIS)

    Metal-contaminated sediments pose a recognised threat to sediment-dwelling fauna. Re-mobilisation of contaminated sediments however, may impact more broadly on benthic ecosystems, including on diverse assemblages living on hard substrata patches immediately above sediments. We used manipulative field experiments to simultaneously test for the effects of metal contamination on recruitment to marine sediments and overlying hard substrata. Recruitment to sediments was strongly and negatively affected by metal contamination. However, while assemblage-level effects on hard-substratum fauna and flora were observed, most functional groups were unaffected or slightly enhanced by exposure to contaminated sediments. Diversity of hard-substratum fauna was also enhanced by metal contamination at one site. Metal-contaminated sediments appear to pose less of a hazard to hard-substratum than sediment-dwelling assemblages, perhaps due to a lower direct contaminant exposure or to indirect effects mediated by contaminant impacts on sediment fauna. Our results indicate that current sediment quality guidelines are protective of hard-substrata organisms. - Highlights: ► Potential for contaminated sediments to exert impacts beyond the sediment communities. ► We examine effects on recruitment to sediments and overlying hard substrata simultaneously. ► Metal-contaminated sediments had a strong negative impact on sediment fauna. ► Metal-contaminated sediments pose less of a hazard to hard-substratum fauna. ► Sediment quality guidelines are likely protective of hard-substrata organisms. - Under natural disturbance regimes, metal-contaminated sediments pose less of a direct risk to hard-substratum fauna than to sediment-dwelling fauna and SQG appear appropriate.

  10. Effect of roof slope and thickness on the performance of a saltstone vault

    International Nuclear Information System (INIS)

    At the Savannah River Site, low-level radioactive decontaminated salt solution is mixed with slag, flyash, and cement to form a grout-like material called ''Saltstone.'' The Saltstone is poured into concrete vaults constructed at the Saltstone Disposal Facility (SDF). The SDF is designed for the release of contaminants in a slow, controlled manner over thousands of years. The impact of SDF on groundwater has been studied in a radiological performance assessment (PA). Groundwater models were used to predict the fluid flow and contaminant transport at SDF. The models predicted a spatial contaminant concentration distribution in groundwater as a function of time. This study focuses on the roof configuration of Saltstone vault, with special interests in cost-effectiveness. We conducted a study to evaluate the effect of roof slope and thickness on the performance of a Saltstone vault. Four roof configurations were simulated. The tool used for the simulation was ECLIPSE, a finite-difference petroleum reservoir engineering code with an environmental tracer option. Nitrate was used as the ''tracer'' contaminant. In this study, ECLIPSE solves the two-phase two-dimensional flow and transport problem up to 10,000 years. This paper describes a modeling study used to evaluate roof design options for the Saltstone vault

  11. Effects of Immersed Surfaces on the Combustor Efficiency of Small-Scale Fluidized Beds

    Directory of Open Access Journals (Sweden)

    Nurdil Eskin

    2005-09-01

    Full Text Available In this study, effects of the different types of heat exchanger surfaces on the second law efficiency of a small-scale circulating fluidized bed (CFB combustor are analyzed and the results are compared with the bubbling fluidized bed coal combustor effectiveness values. Using a previously developed simulation program, combustor efficiency and entropy generation values are obtained at different operation velocities at different height and volume ratios of the immersed surfaces, both for circulating and bubbling fluidized bed combustors. Besides that, the influence of the immersed surface types on the combustor efficiency was compared for different fluidized bed combustors. Through this analysis, the dimensions, arrangement and type of the immersed surfaces which achieve maximum efficiency are obtained.

  12. Pulling up the runaway: the effect of new evidence on euthanasia's slippery slope.

    Science.gov (United States)

    Ryan, C J

    1998-10-01

    The slippery slope argument has been the mainstay of many of those opposed to the legalisation of physician-assisted suicide and euthanasia. In this paper I re-examine the slippery slope in the light of two recent studies that examined the prevalence of medical decisions concerning the end of life in the Netherlands and in Australia. I argue that these two studies have robbed the slippery slope of the source of its power--its intuitive obviousness. Finally I propose that, contrary to the warnings of the slippery slope, the available evidence suggests that the legalisation of physician-assisted suicide might actually decrease the prevalence of non-voluntary and involuntary euthanasia. PMID:9800591

  13. Effect of bed temperature and bed composition on agglomeration during gasification of high-sodium, high-sulphur lignite in a spouted fluidised bed

    Energy Technology Data Exchange (ETDEWEB)

    D.P. McCullough; P.J. Mullinger; P.J. Ashman [University of Adelaide, Adelaide, SA (Australia). Cooperative Research Centre for Clean Power from Lignite, School of Chemical Engineering

    2003-07-01

    Fluidised bed gasification (FBG) is an alternative process for coal utilisation that delivers improved efficiencies and lower temperature operation compared to conventional technology. Agglomeration and defluidisation are phenomena that have the potential to occur within fluidised bed reactors, which can interrupt stable process operation. While extensive work has been carried out investigating fluidised bed combustion of lignite, relatively little work has been carried out for lignite under fluidised bed gasification conditions. Gasification of high sodium, high sulphur content lignite in a spouted bed gasifier (SBG) indicates that agglomeration and defluidisation is only an issue when maximum bed temperature exceeds approximately 850{degree}C and air/fuel ratios of 2.5 outside of these conditions, defluidisation is not detected. It is also demonstrated that defluidisation occurs before agglomeration, rather than as a result of agglomeration as previously thought. The Rosin-Rammler method of describing particle size distribution is found to yield appropriate variables for quantification of the extent of agglomeration taking place in cases where defluidisation is a factor. However, it has been shown by this method that while initial results indicated that agglomeration extent varies directly with maximum bed temperature, further results have shown that other variables, such as superficial velocity, have a significant impact on the extent of agglomeration. Investigations are currently continuing. 9 refs., 8 figs., 9 tabs.

  14. Effective grouting area of jointed slope and stress deformation responses by numerical analysis with FLAC3D

    Institute of Scientific and Technical Information of China (English)

    ZHU Zi-qiang; LIU Qun-yi; ZENG Fan-he; QING Du-gan

    2009-01-01

    To study the grouting reinforcement mechanism in jointed rock slope, first, the theoretical deduction was done to calculate the critical length of slipping if the slope angle is larger than that of joint inclination; Second, the numerical calculation model was founded by FLAG3D, so as to find the stress and deformation responses of rock mass in the state before and after grouting, the analysis results show that the range between the boundary of critical slipping block and the joint plane that passes the slope toe is the effective grouting area (EGA). After excavation, large deformation occurs along the joint plane. After grouting, the displacements of rock particles become uniform and continuous, and large deformations along the joint plane are controlled; the dynamic displacement can reflect the deformation response of slope during excavation in the state before and after grouting, as well as the shear location of potential slip plane. After grouting, the dynamic displacement of each monitoring point reaches the peak value with very few time steps,which indicate that the parameters of the joint plane, such as strength and stiffness, are improved; the stress field becomes uniform. Tensile area reduces gradually; whole stability of the slope and its ability to resist tensile and shear stress are improved greatly.

  15. Effect of secondary air injection on the combustion efficiency of sawdust in a fluidized bed combustor

    OpenAIRE

    K. V. N. Srinivasa Rao; G. Venkat Reddy

    2008-01-01

    Agricultural wastes like bagasse, paddy husks, sawdust and groundnut shells can be effectively used as fuels for fluidized bed combustion; otherwise these biomass fuels are difficult to handle due to high moisture and fines content. In the present work the possibility of using sawdust in the fluidized bed combustor, related combustion efficiencies and problems encountered in the combustion process are discussed. The temperature profiles for sawdust with an increase in fluidizing velocity alon...

  16. The Effects of Long Duration Bed Rest on Brain Functional Connectivity and Sensorimotor Functioning

    Science.gov (United States)

    Cassady, K.; Koppelmans, V.; De Dios, Y.; Stepanyan, V.; Szecsy, D.; Gadd, N.; Wood, S.; Reuter-Lorenz, P.; Castenada, R. Riascos; Kofman, I.; Bloomberg, J.; Mulavara, A; Seidler, R.

    2016-01-01

    Long duration spaceflight has been associated with detrimental alterations in human sensorimotor functioning. Prolonged exposure to a head-down tilt (HDT) position during long duration bed rest can resemble several effects of the microgravity environment such as reduced sensory inputs, body unloading and increased cephalic fluid distribution. The question of whether microgravity affects other central nervous system functions such as brain functional connectivity and its relationship with behavior is largely unknown, but of importance to the health and performance of astronauts both during and post-flight. In the present study, we investigate the effects of prolonged exposure to HDT bed rest on resting state brain functional connectivity and its association with behavioral changes in 17 male participants. To validate that our findings were not due to confounding factors such as time or task practice, we also acquired resting state functional magnetic resonance imaging (rs-fMRI) and behavioral measurements from 14 normative control participants at four time points. Bed rest participants remained in bed with their heads tilted down six degrees below their feet for 70 consecutive days. Rs-fMRI and behavioral data were obtained at seven time points averaging around: 12 and 8 days prior to bed rest; 7, 50, and 70 days during bed rest; and 8 and 12 days after bed rest. 70 days of HDT bed rest resulted in significant increases in functional connectivity during bed rest followed by a reversal of changes in the post bed rest recovery period between motor cortical and somatosensory areas of the brain. In contrast, decreases in connectivity were observed between temporoparietal regions. Furthermore, post-hoc correlation analyses revealed a significant relationship between motor-somatosensory network connectivity and standing balance performance changes; participants that exhibited the greatest increases in connectivity strength showed the least deterioration in postural

  17. The Effect of Climbing Ability and Slope Inclination on Vertical Foot Loading Using a Novel Force Sensor Instrumentation System

    OpenAIRE

    Baláš Jiří; Panáčková Michaela; Jandová Soňa; Martin Andrew J.; Strejcová Barbora; Vomáčko Ladislav; Charousek Jan; Cochrane Darryl J.; Hamlin Mike; Draper Nick

    2014-01-01

    The aim of the study was to assess the effects of climbing ability and slope inclination on vertical loading both in terms the forces involved and physiological responses. Five novice and six intermediate female climbers completed a climbing route at three slope inclinations (85°, 90°, and 98°). The vertical loading during the climb was assessed by force-time integral using a Novel Pedar-X insole and physiological responses via oxygen uptake and heart rate. The novice climbers had a significa...

  18. Estimation of infiltration rate, run-off and sediment yield under simulated rainfall experiments in upper Pravara Basin, India: Effect of slope angle and grass-cover

    Indian Academy of Sciences (India)

    Veena U Joshi; Devidas T Tambe

    2010-12-01

    The main objective of this study is to measure the effect of slope and grass-cover on in filtration rate, run-off and sediment yield under simulated rainfall conditions in a badland area located in the upper Pravara Basin in western India. An automatic rainfall simulator was designed following Dunne et al (1980) and considering the local conditions. Experiments were conducted on six selected experimental fields of 2 × 2 m within the catchment with distinct variations in surface characteristics –grass-covered area with gentle slope, recently ploughed gently sloping area, area covered by crop residue (moderate slope), bare badland with steep slope, gravelly surface with near flat slope and steep slope with grass-cover. The results indicate subtle to noteworthy variations amongst the plots depending on their slope angle and surface characteristics. An important finding that emerges from the study is that the grass-cover is the most effective measure in inducing infiltration and in turn minimizing run-off and sediment yield. Sediment yields are lowest in gently sloping grass-covered surfaces and highest in bare badland surfaces with steep slopes. These findings have enormous implication for this area, because over 2/3 area is characterized by bare and steep slopes.

  19. Effect of ash content on the combustion process of simulated MSW in the fixed bed.

    Science.gov (United States)

    Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

    2016-02-01

    This paper experimentally and numerically investigates the effects of ash content on the combustion process of simulated Municipal Solid Waste (MSW). A fixed-bed experimental reactor was utilized to reveal the combustion characteristics. Temperature distributions, ignition front velocity, and the characteristics of gas species' release were measured and simulated during the combustion process. In the present work, the two-dimensional unsteady mathematical heterogeneous model was developed to simulate the combustion process in the bed, including the process rate model as well as NOx production model. The simulation results in the bed are accordant with the experimental results. The results show that as ash content increases, the lower burning rate of fuel results in char particles leaving the grate without being fully burned, causing a loss of combustible material in the MSW in a fixed bed and therefore reducing the combustion efficiency and increasing the burning time of the MSW. PMID:26476592

  20. The effect of an acoustic field on the filtration efficiency of aerosols by a granular bed

    International Nuclear Information System (INIS)

    A theoretical and an experimental study were developed in order to evaluate the parameters controlling the aerosol collection efficiency of a granular bed, i.e. all the chief collection mechanisms and the effect of acoustic waves on this efficiency. The action of acoustic waves of appropriate intensity and frequency increased the efficiency of the granular bed significantly for all aerosol sizes including those corresponding to the minimum efficiency. The theoretical prediction was verified by an experimental apparatus using a granular bed of glass of 2 mm diameter. Furthermore, our experimental results demonstrated the existence of a threshold in the acoustic intensity above which the collection efficiency of the granular bed increased rapidly. We also demonstrated a semi-empirical law relating acoustic capture efficiency of a spherical collector to frequency and acoustic intensity

  1. Comparative Study of Guizhou Sloping Land Soil and Water Conservation Effect of the Three Cropping Patterns

    Institute of Scientific and Technical Information of China (English)

    Zhenggang; CHEN; Yanhua; XIONG; Jian; LI; Qing; ZHU

    2013-01-01

    Surface cover degree,monthly variation of topsoil water content,loss of soil and nutrient in alfalfa-corn intercropping,strip rotation cropping and corn monoculture were studied in this paper. Then soil and water conservation effect of these planting modes were compared. Results showed that surface cover degree was high during the all rainy season in both alfalfa-corn intercropping and strip rotation cropping mode, with slope field covered by vegetation all the year round. Roots of alfalfa grew well,which not only improved the root biomass in 0-20cm layer,enhanced the capacity of the infiltration of rainwater to soil,protected biodiversity,but also reduced surface off and soil erosion of 39. 3% and 59. 3% . Strip rotation cropping could also reduce surface off and soil erosion of 10. 4% and 21. 3% . Both alfalfa-corn intercropping and strip rotation cropping increased soil moisture in rainy season and before rainy season,whilst reduced loss of organic matter (caused by soil erosion) of 29. 9%-52. 4% ,total N of 26. 7%-54. 9% ,total K of 27. 3%-70. 9% ,slow available K of 21. 4%-58. 9% ,increased corn production of 33. 0%-35. 9% . Moreover,there was 13664kg/hm 2 in alfalfa-corn intercropping,which was 4. 1 times higher than common mode. There was 12492 kg/hm 2 in strip rotation cropping which was 2. 7 times higher than common mode.

  2. Effects of Bed Rest on Conduction Velocity of the Triceps Surae Stretch Reflex and Postural Control

    Science.gov (United States)

    Reschke, M. F.; Wood, S. J.; Cerisano, J. M.; Kofman, I. S.; Fisher, E. A.; Esteves, J. T.; Taylor, L. C.; DeDios, Y. E.; Harm, D. L.

    2011-01-01

    Despite rigorous exercise and nutritional management during space missions, astronauts returning from microgravity exhibit neuromuscular deficits and a significant loss in muscle mass in the postural muscles of the lower leg. Similar changes in the postural muscles occur in subjects participating in long-duration bed rest studies. These adaptive muscle changes manifest as a reduction in reflex conduction velocity during head-down bed rest. Because the stretch reflex encompasses both the peripheral (muscle spindle and nerve axon) and central (spinal synapse) components involved in adaptation to calf muscle unloading, it may be used to provide feedback on the general condition of neuromuscular function, and might be used to evaluate the effectiveness of countermeasures aimed at preserving muscle mass and function during periods of unloading. Stretch reflexes were measured on 18 control subjects who spent 60 to 90 days in continuous 6 deg head-down bed rest. Using a motorized system capable of rotating the foot around the ankle joint (dorsiflexion) through an angle of 10 degrees at a peak velocity of about 250 deg/sec, a stretch reflex was recorded from the subject's left triceps surae muscle group. Using surface electromyography, about 300 reflex responses were obtained and ensemble-averaged on 3 separate days before bed rest, 3 to 4 times in bed, and 3 times after bed rest. The averaged responses for each test day were examined for reflex latency and conduction velocity (CV) across gender. Computerized posturography was also conducted on these same subjects before and after bed rest as part of the standard measures. Peak-to-peak sway was measured during Sensory Organization Tests (SOTs) to evaluate changes in the ability to effectively use or suppress visual, vestibular, and proprioceptive information for postural control. Although no gender differences were found, a significant increase in reflex latency and a significant decrease in CV were observed during the bed

  3. Effect of graph generation on slope stability analysis based on graph theory

    Institute of Scientific and Technical Information of China (English)

    Enpu Li; Xiaoying Zhuang; Wenbo Zheng; Yongchang Cai

    2014-01-01

    Limit equilibrium method (LEM) and strength reduction method (SRM) are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of bench-mark examples and a rock slope show good accuracy and efficiency of the presented method.

  4. Effect of graph generation on slope stability analysis based on graph theory

    Directory of Open Access Journals (Sweden)

    Enpu Li

    2014-08-01

    Full Text Available Limit equilibrium method (LEM and strength reduction method (SRM are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of benchmark examples and a rock slope show good accuracy and efficiency of the presented method.

  5. Effect of minimal shoes and slope on vertical and leg stiffness during running

    Directory of Open Access Journals (Sweden)

    Thibault Lussiana

    2015-06-01

    Conclusion: This study showed that kvert and kleg during running respond differently to change in footwear and/or slope. These two stiffness measures can hence provide a unique insight on the biomechanical adaptations of running under varying conditions and their respective quantification may assist in furthering our understanding of training, performance, and/or injury in this sport.

  6. The Effect of Climbing Ability and Slope Inclination on Vertical Foot Loading Using a Novel Force Sensor Instrumentation System

    Directory of Open Access Journals (Sweden)

    Baláš Jiří

    2014-12-01

    Full Text Available The aim of the study was to assess the effects of climbing ability and slope inclination on vertical loading both in terms the forces involved and physiological responses. Five novice and six intermediate female climbers completed a climbing route at three slope inclinations (85°, 90°, and 98°. The vertical loading during the climb was assessed by force-time integral using a Novel Pedar-X insole and physiological responses via oxygen uptake and heart rate. The novice climbers had a significantly lower (p < 0.05 vertical loading on foot holds and higher oxygen uptake and heart rate compared to intermediate climbers. A significant negative correlation was identified between the force-time integral and oxygen uptake (R = -0.72, and with heart rate (R = -0.64, respectively. The time-force integral decreased across the ascents with increasing slope inclination (p < 0.001. The results indicate that more advanced ability climbers make greater use of foot holds, with associated lowering in physiological response (oxygen uptake and heart rate across all slope inclinations.

  7. Effect of pouring temperature on cooling slope casting of semi-solid Al-Si-Mg alloy

    Institute of Scientific and Technical Information of China (English)

    Prosenjit Das; Sudip K. Samanta; Himadri Chattopadhyay; Pradip Dutta

    2012-01-01

    Present trend of semi-solid processing is directed towards rheocasting route which allows manufacturing of near-net-shape cast components directly from the prepared semi-solid slurry.Generation of globular equi-axed grains during solidification of rheocast components,compared to the columnar dendritic structure of conventional casting routes,facilitates the manufacturing of components with improved mechanical properties and structural integrity.In the present investigation,a cooling slope has been designed and indigenously fabricated to produce semi solid slurry of Al-Si-Mg (A356) alloy and successively cast in a metallic mould.The scope of the present work discusses about development of a numerical model to simulate the liquid metal flow through cooling slope using Eulerian two-phase flow approach and to investigate the effect of pouring temperature on cooling slope semi-solid slurry generation process.The two phases considered in the present model are liquid metal and air.Solid fraction evolution of the solidifying melt is tracked at different locations of the cooling slope,following Schiel's equation.The continuity equation,momentum equation and energy equation are solved considering thin wall boundary condition approach.During solidification of the liquid metal,a modified temperature recovery scheme has been employed taking care of the latent heat release and change of fraction of liquid.The results obtained from simulations are compared with experimental findings and good agreement has been found.

  8. SEASONAL REVERSE OF SEA SURFACE SLOPE IN THE NORTHERN YELLOW SEA AND ITS DYNAMIC RELATION WITH MONSOON EFFECTS

    Institute of Scientific and Technical Information of China (English)

    PU Shu-zhen; CHENG Jun; ZHANG Yi-jun; SHI Qiang

    2004-01-01

    Based on the monthly average sea level data from the tide gauge measurement(1999-2001),the seasonal variability of the sea level in the Northern and Middle Yellow Sea is studied to reveal that the sea surface height at all the tide gauges becomes higher in summer than that in winter.In addition,the sea surface height of the Northern Yellow Sea is higher than the one of the Middle Yellow Sea with a slope downward from the north to the south in summer,while it is lower with a reversed slope in winter.The seasonal reverse of the sea surface slope can be attributed to the monsoon effects i.e.the annual reverse of the monsoon direction and the annual variation of the monsoon rainfall.A set of equations are established in light of the dynamic principles to expound how the monsoon forcing and the sea surface slope generate a summer outflow and a winter inflow in the Yellow Sea.

  9. Experimental Investigation of the Effect of Particle Shape on Frictional Pressure drop in Particulate Debris Bed

    International Nuclear Information System (INIS)

    To ensure the long-term cooling of corium in the reactor cavity, it is important to ensure the coolant ingression into the internally heat generated corium debris bed which is governed by pressure drop in porous media. For this reason, it is necessary to understand pressure drop mechanisms in porous bed to verify the feasibility of water penetration into particulate debris bed. According to the previous investigations on molten fuel-coolant interaction (FCI) experiments, it was found that quenched particulate debris bed was composed of irregular shape particles. Therefore, empirical or semiempirical models based on the Ergun equation (Ergun, 1952) for single-phase flow in porous media composed of single sized spherical particle were developed to consider the effect of particle shape on frictional pressure drop by means of adding a shape factor or modifying the Ergun constants etc. (Leva, 1959, Handley and Heggs, 1968, Macdonald, 1979, Foumeny et al., 1996). An experimental investigate on single-phase frictional pressure drop of water in packed bed was conducted in the transparent cylindrical test section with the inner diameter of 100 mm and the height of 700 mm to study the effect of particle shape on frictional pressure drop in porous media. This paper reports the experimental data for spherical particles with the diameter of 2 mm and 5 mm and cylindrical particles with ED of 2 mm and 5 mm. And also, the experimental data compared with the models to predict frictional pressure drop in particulate bed. The conclusions are summarized as follows. As a result of the experiment to measure frictional pressure drop in particulate bed composed of cylindrical particles the models predict the experimental data well within 22.11 % except the Handley and Heggs model when ED is applied to the models

  10. Experimental Investigation of the Effect of Particle Shape on Frictional Pressure drop in Particulate Debris Bed

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ho; Kim, Eun Ho; Park, Hyun Sun [POSTECH, Pohang (Korea, Republic of)

    2014-10-15

    To ensure the long-term cooling of corium in the reactor cavity, it is important to ensure the coolant ingression into the internally heat generated corium debris bed which is governed by pressure drop in porous media. For this reason, it is necessary to understand pressure drop mechanisms in porous bed to verify the feasibility of water penetration into particulate debris bed. According to the previous investigations on molten fuel-coolant interaction (FCI) experiments, it was found that quenched particulate debris bed was composed of irregular shape particles. Therefore, empirical or semiempirical models based on the Ergun equation (Ergun, 1952) for single-phase flow in porous media composed of single sized spherical particle were developed to consider the effect of particle shape on frictional pressure drop by means of adding a shape factor or modifying the Ergun constants etc. (Leva, 1959, Handley and Heggs, 1968, Macdonald, 1979, Foumeny et al., 1996). An experimental investigate on single-phase frictional pressure drop of water in packed bed was conducted in the transparent cylindrical test section with the inner diameter of 100 mm and the height of 700 mm to study the effect of particle shape on frictional pressure drop in porous media. This paper reports the experimental data for spherical particles with the diameter of 2 mm and 5 mm and cylindrical particles with ED of 2 mm and 5 mm. And also, the experimental data compared with the models to predict frictional pressure drop in particulate bed. The conclusions are summarized as follows. As a result of the experiment to measure frictional pressure drop in particulate bed composed of cylindrical particles the models predict the experimental data well within 22.11 % except the Handley and Heggs model when ED is applied to the models.

  11. A STUDY OF TEACHER EFFECTIVENESS OF DEGREE AND B.ED. COLLEGE TEACHERS OF RAJASTHAN IN RELATION TO LOCALITY

    OpenAIRE

    Rajender Kumar

    2016-01-01

    This study aimed to find out difference in teacher effectiveness of degree and B.Ed. college teachers of Rajasthan. The Teacher Effectiveness Scale by Dr.Shallu Puri and Prof. S.C. Gakhar was used to assess the teacher effectiveness of degree and B.Ed. college teachers of Rajasthan. The scale was administered on 160 degree and B.Ed. college teachers. The present study revealed that there is no significant difference in teacher effectiveness of degree and B.Ed. college teachers.

  12. Effect of alternative solid fuels on desulfurization of fluidized bed boilers

    International Nuclear Information System (INIS)

    Laboratory research revealed a negative effect of ash formed during combustion of industrial and municipal waste in fluidized bed boilers. The reactivity of limestone used for desulfurization during the combustion reacts with the ash. The negative effect can be attributed to the oxides coating on the surface of calcined limestone. (author)

  13. The effect of different methods of seed bed preparation on greenhouse cucumber yield and yield components

    Directory of Open Access Journals (Sweden)

    D. Momeni

    2010-12-01

    Full Text Available To investigate the effects of different methods of seed bed preparation on yield of greenhouse cucumber, a two-year long experiment was conducted as a randomized complete block design with four replications in Jiroft from 2004. Different methods of seed bed preparation were as follows: 1 ridge with 20 cm height and 50 cm width and 2 plant rows with 40 cm distance, 2 furrow with 20 cm depth and 50 cm width and 2 plant rows inside, with 40 cm distance, and 3 planting on flat area with 40 cm distance. The results showed that the effect of planting bed on yield of greenhouse cucumber was significant. Furrow and flat area increased yield significantly, compared to the ridge treatment. Analysis of yield components such as plant height, number of pickling fruits, number of leaves, photosynthetic area and number of flowers showed that they are all correlated with fruit yield. The number of pickling fruits was significantly more in furrow and flat area than in ridge treatment. The height of cucumber plants on flat bed was significantly higher than that of the other treatments. The number of leaves and photosynthetic area of plants on flat bed were significantly greater than those in the other treatments. The least dead plants due to fungi disease were observed in ridge treatment. In view of yield and its components under the condition of this experiment, it can be concluded that flat area and furrow treatments are better than ridge treatment.

  14. Development of Bed Ridges in Open Channels and their Effects on Secondary Currents and Wall Shear

    Directory of Open Access Journals (Sweden)

    Kamran Ansari

    2012-07-01

    Full Text Available A numerical analysis of the ridges on the bed of wide, open channels and their effects on the distribution of secondary currents and wall shear is undertaken using CFD (Computational Fluid Dynamics. The presence of the lines of boil, consisting of low speed streaks, periodically in the transverse direction, is reported in the literature due to the presence of the ridges. In the present work, simulations are run on channel sections with varying the number of ridges on the bed and the size of these ridges. The effect of these variations on the flow structures and shear stress distribution in wide open channels is reported. The results offer an interesting insight into the 3D (Three-Dimensional flow structures involved and the link between flow structures and bed morpho-dynamics in prismatic channels.

  15. Livestock bedding effects on two species of parasitoid wasps of filth flies.

    Science.gov (United States)

    King, B H; Colyott, K L; Chesney, A R

    2014-01-01

    Choice of livestock bedding has been shown to affect density of filth fly maggots. Here, laboratory experiments indicate that bedding type can also affect natural enemies of the flies, specifically the parasitoid wasps Spalangia endius Walker and Urolepis rufipes (Ashmead) (Hymenoptera: Pteromalidae) parasitizing a natural host, the house fly Musca domestica L. (Diptera: Muscidae). For both parasitoid species, when females parasitized hosts under bedding, cedar shavings resulted in fewer parasitoids compared with pine shavings, but pine shavings did not differ from wood pellets and corn cob pellets. In the absence of exposure to hosts, longevity of adult females was reduced in cedar shavings compared with pine shavings and pellets. In contrast to the effects on parasitization and on adult survival, shavings treatment had no significant effect on the number of parasitoids or flies that emerged when hosts were not exposed to shavings until after parasitization. PMID:25480971

  16. Quantifying the effects of hydrograph shape and flow transience on coarse sediment bed load transport

    Science.gov (United States)

    Phillips, Colin; Hill, Kimberly; Paola, Chris

    2016-04-01

    The rate of bed load transport under steady flow is known to vary both spatially and temporally due to various hydrologic and granular phenomena. Grain size distributions and riverbed properties (packing, armoring, imbrication, etc.) have been observed to affect flux for a particular value of applied flow stress while hydrology is mainly assumed to control the magnitude of the applied bed stress above the threshold for bed material entrainment. The prediction and measurement of bed load sediment transport in field settings are further complicated by the inherent transience in the flood hydrograph, but relatively little is known about how flood transience differs from a steady flow. Here we investigate the role of flood transience for gravel bed load transport through controlled laboratory experiments in a 28 m long 0.5-meter wide flume. We explore transient flow through the use of short duration hydrographs as the combination of unsteady and intermittent flow, where unsteady flow varies in magnitude over a given duration, and intermittent flow is characterized by turning the flow on and off. Experimental runs consist of sequences of steady and unsteady flood hydrographs of various shapes, but equivalent integrated excess transport capacity. These flood sequences are run for a variety of competent flow durations and peak stress magnitudes. We find that even for a narrow unimodal grain size distribution and constant sediment supply we observe clockwise hysteresis in bed load flux, different thresholds for entrainment and distrainment for the rising and falling limbs of a flood, and a threshold of entrainment that can vary from one flood hydrograph to the next. Despite complex transport phenomena at the particle scale, we find that the total bed load transported for each flood plots along a linear trend with the integrated excess transport capacity, in agreement with prior field results. These experiments indicate that while the effects of transient flow and

  17. Dip-slope and Dip-slope Failures in Taiwan - a Review

    Science.gov (United States)

    Lee, C.

    2011-12-01

    Taiwan is famous for dip-slope and dip-slope slides. Dip-slopes exist at many places in the fold-and-thrust belt of Taiwan. Under active cutting of stream channels and man-made excavations, a dip-slope may become unstable and susceptible for mass sliding. Daylight of a bedding parallel clay seam is the most dangerous type for dip-slope sliding. Buckling or shear-off features may also happen at toe of a long dip-slope. Besides, a dip-slope is also dangerous for shallow debris slides, if the slope angle is between 25 to 45 degrees and the debris (colluvium or slope wash) is thick (>1m). These unstable slopes may slide during a triggering event, earthquake or typhoon storm; or even slide without a triggering event, like the 2010 Tapu case. Initial buckling feature had been found in the dip-slope of the Feitsui arch dam abutment after detailed explorations. Shear-off feature have also been found in dip-slope located in right bank of the Nahua reservoir after field investigation and drilling. The Chiufengerhshan slide may also be shear-off type. On the other hand, the Tapu, the Tsaoling slides and others are of direct slide type. The Neihoo Bishan slide is a shallow debris slide on dip-slope. All these cases demonstrate the four different types of dip-slope slide. The hazard of a dip-slope should be investigated to cover these possible types of failure. The existence of bedding parallel clay seams is critical for the stability of a dip-slope, either for direct slide or buckling or shear-off type of failure, and is a hot point during investigation. Because, the stability of a dip-slope is changing with time, therefore, detailed explorations to including weathering and erosion rates are also very necessary to ensure the long-term stability of a dip-slope.

  18. Effects of continuous vs interval exercise training on oxygen uptake efficiency slope in patients with coronary artery disease

    OpenAIRE

    Prado, D.M.L.; Rocco, E.A.; A.G. Silva; Rocco, D.F.; M.T. Pacheco; Silva, P.F.; V. Furlan

    2016-01-01

    The oxygen uptake efficiency slope (OUES) is a submaximal index incorporating cardiovascular, peripheral, and pulmonary factors that determine the ventilatory response to exercise. The purpose of this study was to evaluate the effects of continuous exercise training and interval exercise training on the OUES in patients with coronary artery disease. Thirty-five patients (59.3±1.8 years old; 28 men, 7 women) with coronary artery disease were randomly divided into two groups: continuous exercis...

  19. A new approach to integrate effects of changes in vegetation cover in slope stability assessment.

    OpenAIRE

    Vandromme, Rosalie; Desramaut, Nicolas

    2013-01-01

    Global changes would have direct impacts on landslide activities through the modifications of the triggering events with the evolutions of climate forcing. However, some predisposing factors would also evolve, like, for example, the vegetation covers. Indeed, forests are likely to be modified, either by anthropogenic interventions, natural ageing or adapting to climate change. And this evolution is likely to result in changes of the susceptibilities of slopes to landslides. In order to propos...

  20. Lateral Slope Effect on Tipping Behavior of a Tractor Encountering an Obstacle (Model Development)

    OpenAIRE

    LI, ZHEN; Mitsuoka, Muneshi; Inoue, Eiji; Okayasu, Takashi; Hirai, Yasumaru

    2014-01-01

    A three–dimensional mathematical model of tractor on lateral slopes was developed in this study. The model considers the nonlinear geometric relationships of the arms of the ground supporting forces when the tractor passes over a half sine curve obstacle. It is subsequently ap–plicable to large rotations of a tractor. Meanwhile, the change of the direction of a supporting force due to the interaction between tractor pitch and roll motions and its result in corresponding tire deformation are t...

  1. An overview of the issues: physiological effects of bed rest and restricted physical activity

    Science.gov (United States)

    Convertino, V. A.; Bloomfield, S. A.; Greenleaf, J. E.

    1997-01-01

    Reduction of exercise capacity with confinement to bed rest is well recognized. Underlying physiological mechanisms include dramatic reductions in maximal stroke volume, cardiac output, and oxygen uptake. However, bed rest by itself does not appear to contribute to cardiac dysfunction. Increased muscle fatigue is associated with reduced muscle blood flow, red cell volume, capillarization and oxidative enzymes. Loss of muscle mass and bone density may be reflected by reduced muscle strength and higher risk for injury to bones and joints. The resultant deconditioning caused by bed rest can be independent of the primary disease and physically debilitating in patients who attempt to reambulate to normal active living and working. A challenge to clinicians and health care specialists has been the identification of appropriate and effective methods to restore physical capacity of patients during or after restricted physical activity associated with prolonged bed rest. The examination of physiological responses to bed rest deconditioning and exercise training in healthy subjects has provided significant information to develop effective rehabilitation treatments. The successful application of acute exercise to enhance orthostatic stability, daily endurance exercise to maintain aerobic capacity, or specific resistance exercises to maintain musculoskeletal integrity rather than the use of surgical, pharmacological, and other medical treatments for clinical conditions has been enhanced by investigation and understanding of underlying mechanisms that distinguish physical deconditioning from the disease. This symposium presents an overview of cardiovascular and musculoskeletal deconditioning associated with reduced physical work capacity following prolonged bed rest and exercise training regimens that have proven successful in ameliorating or reversing these adverse effects.

  2. Effect of Slope Plate Variable and Reheating on the Semi-Solid Structure of Ductile Cast Iron

    Institute of Scientific and Technical Information of China (English)

    M. Nili-Ahmadabadi; F. Pahlevani; P. Babaghorbani

    2008-01-01

    Semi-solid metal casting and forming is a promising production method for a wide range of metal alloys. In spite of many applications for semi-solid processed light alloys, few works have reported on the semi-solid processing of iron and steel. In this research, an inclined plate was used to change the dendritic structure of iron to globular. The effects of the length and slope of the plate on the casting structure were examined. The results show that the process effectively changes the dendritic structure to globular. A sloped plate angle of 7.5° and length of 560 mm with a cooling rate of 67 K·s-1 gave the optimum graphite nodu-larity and solid particle globularity. The results also show that the sloped plate more easily prevents inocu-lant fading since the total time processing is rather short. In addition the semi-solid ductile cast iron prepared using the inclined plate method was reheated to examine the effect of reheating conditions on the micro-structure and coarsening kinetics of the alloy. The solid fractions at different reheating temperatures and holding times were used to find the optimum reheating temperature range.

  3. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2015-09-01

    Full Text Available This paper focuses on assessment of the effect of flue gas recirculation (FGR on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  4. The metabolic and hemodynamic effects of prolonged bed rest in normal subjects

    Science.gov (United States)

    Chobanian, A. V.; Lille, R. D.; Tercyak, A.; Blevins, P.

    1974-01-01

    Investigation in six normal subjects of the effects of chronic bed rest on the interrelationships between cardiovascular hemodynamics, catecholamine metabolism, vascular reactivity, renin and aldosterone activity, and electrolyte and fluid balance. Negative sodium and potassium balances and reductions in plasma volume were observed in all subjects, but plasma renin activity and aldosterone secretory rate showed no significant change. Other findings included the observation that major decreases in sodium balance and plasma volume occurred in the early bed rest period and did not correlate closely with the degree of orthostatic intolerance.

  5. Effect of Temperature in Fluidized Bed Fast Pyrolysis of Biomass: Oil Quality Assessment in Test Units

    NARCIS (Netherlands)

    Westerhof, R.J.M.; Brilman, D.W.F.; Swaaij, van W.P.M.; Kersten, S.R.A.

    2010-01-01

    Pine wood was pyrolyzed in a 1 kg/h fluidized bed fast pyrolysis reactor that allows a residence time of pine wood particles up to 25 min. The reactor temperature was varied between 330 and 580 °C to study the effect on product yields and oil composition. Apart from the physical−chemical analysis, a

  6. Experimental investigation of a draft tube spouted bed for effects of geometric parameters on operation

    DEFF Research Database (Denmark)

    Azizaddini, Seyednezamaddin; Lin, Weigang; Dam-Johansen, Kim

    2016-01-01

    Experiments are performed in a draft tube spouted bed (DTSB) to investigate effects of the operating conditions and the geometric parameters on the hydrodynamics. Geometry parameters, such as heights of the entrained zone, draft tube inner diameter, inner angle of the conical section were studied...

  7. Effects of refraction on transmission spectra of gas giants: decrease of the Rayleigh scattering slope and breaking of retrieval degeneracies

    CERN Document Server

    Bétrémieux, Yan

    2015-01-01

    Detection of the signature of Rayleigh scattering in the transmission spectrum of an exoplanet is increasingly becoming the target of observational campaigns because the spectral slope of the Rayleigh continuum enables one to determine the scaleheight of its atmosphere in the absence of hazes. However, this is only true when one ignores the refractive effects of the exoplanet's atmosphere. I illustrate with a suite of simple isothermal clear Jovian H2-He atmosphere models with various abundances of water that refraction can decrease significantly the spectral slope of the Rayleigh continuum and that it becomes flat in the infrared. This mimics a surface, or an optically thick cloud deck, at much smaller pressures than one can probe in the non-refractive case. Although the relative impact of refraction on an exoplanet's transmission spectrum increases with decreasing atmospheric temperatures as well as increasing stellar temperature, it is still quite important from a retrieval's perspective even for a Jovian-...

  8. Simulating run-up on steep slopes with operational Boussinesq models; capabilities, spurious effects and instabilities

    Directory of Open Access Journals (Sweden)

    F. Løvholt

    2013-06-01

    Full Text Available Tsunamis induced by rock slides plunging into fjords constitute a severe threat to local coastal communities. The rock slide impact may give rise to highly non-linear waves in the near field, and because the wave lengths are relatively short, frequency dispersion comes into play. Fjord systems are rugged with steep slopes, and modeling non-linear dispersive waves in this environment with simultaneous run-up is demanding. We have run an operational Boussinesq-type TVD (total variation diminishing model using different run-up formulations. Two different tests are considered, inundation on steep slopes and propagation in a trapezoidal channel. In addition, a set of Lagrangian models serves as reference models. Demanding test cases with solitary waves with amplitudes ranging from 0.1 to 0.5 were applied, and slopes were ranging from 10 to 50°. Different run-up formulations yielded clearly different accuracy and stability, and only some provided similar accuracy as the reference models. The test cases revealed that the model was prone to instabilities for large non-linearity and fine resolution. Some of the instabilities were linked with false breaking during the first positive inundation, which was not observed for the reference models. None of the models were able to handle the bore forming during drawdown, however. The instabilities are linked to short-crested undulations on the grid scale, and appear on fine resolution during inundation. As a consequence, convergence was not always obtained. It is reason to believe that the instability may be a general problem for Boussinesq models in fjords.

  9. Processes of bedrock groundwater seepage and their effects on soil water fluxes in a foot slope area

    Science.gov (United States)

    Masaoka, Naoya; Kosugi, Ken'ichirou; Yamakawa, Yosuke; Tsutsumi, Daizo

    2016-04-01

    The impact of bedrock groundwater seepage on surface hydrological processes in a foot slope area is an important issue in hillslope hydrology. However, properties of water flux vectors around a seepage area are poorly understood because previous studies have lacked sufficient spatial resolution to capture detailed water movements. Here, we conducted hydrometric observations using unprecedented high-resolution and three-dimensional tensiometer nests in the mountainous foot slope area of the Hirudani experimental basin (Japan). Our findings are summarized as follows: (1) a considerable quantity of groundwater seeped from the bedrock surface in the study site. A groundwater exfiltration flux occurred constantly from a seepage area regardless of rainfall conditions. Saturated lateral flow over the bedrock surface occurred constantly in the region downslope of the seepage area. Groundwater was likely to mixed with soil water infiltration and flowed toward the lower end of the slope. (2) During the wet season, the seepage area expanded ∼3 m in the upslope direction along the bedrock valley in a single season. (3) The pressure head waveform observed in the seepage area showed gradual and significant increases after large rainfall events. However, the seepage pressure propagated within a relatively narrow area: a slope distance of ∼4 m from the seepage point in the downslope direction due to the damping of seepage pressure. (4) Within the whole study area, groundwater seeped from a narrow area located at the bottom of the valley line of the bedrock surface. The shape of the seepage area changed along the valley line in the wet season. Overall, we reveal spatial and temporal variations in bedrock groundwater seepage under the soil mantle and the effects on soil water fluxes. These findings should improve the accuracy of models for predicting surface hydrogeomorphological processes in mountainous hillslopes.

  10. Analytical solution of coal-bed methane migration with slippage effects in hvpotonic reservoir

    Institute of Scientific and Technical Information of China (English)

    XIAO Xiao-chun; PAN Yi-shan; YU Li-yan; JIANG Chun-yu

    2011-01-01

    Using theoretical analysis, the single-phase gas seepage mathematical model influenced by slippage effects was established. The results show that the pressure of producing wells attenuates more violently than the wells without slippage effects. The decay rate of reservoir pressure is more violent as the Klinkenberg factor increases. The gas prediction output gradually increases as the Klinenberg factor increases when considering gas slippage effects. Through specific examples, analyzed the law of stope pore pressure and gas output forecast changing in a hypotonic reservoir with slippage effects. The results have great theoretical significance in the study of the law of coal-bed methane migration in hypotonic reservoirs and for the exploitation of coal-bed methane.

  11. EFFECTIVENESS OF THE BANGALORE UNIVERSITY B.ED CURRICULUM IN DEVELOPING PROPER ATTITUDE TOWARDS TEACHING PROFESSION

    OpenAIRE

    N.N.Prahallada

    2016-01-01

    The present study explored the variables that contribute to the effectiveness of teachers training program in Bangalore University for the education sector. A sample of 52 students were selected which included both male and female teacher trainees of B.E.S B.Ed. College; with the help of a research questionnaire their response was recorded. This study determined that their effectiveness could have been increased if rigorous training need analysis had been done. The study also finds that facto...

  12. Effects of periodicity on flow and dispersion through closely packed fixed beds of spheres

    Science.gov (United States)

    Reynolds, A. M.

    2002-02-01

    A lattice-Boltzmann formulation is used to investigate the effects of ``periodicity'' (geometry) on fluid flow and tracer-particle dispersion through fixed beds of spheres comprising of closely packed layers. In the ``period-1'' arrangement, spheres in the adjacent layers contact at their poles while the ``period-2'' and ``period-3'' arrangements correspond to hexagonal and faced-centered cubic close packing. For all three packing arrangements, there is a transition with increasing Reynolds number from a power law to a log-normal distribution of kinetic energies and, velocity and vorticity become more closely aligned giving rise to helical tracer-particle trajectories. It is suggested that these flow characteristics, unlike the stability of flow and the distribution of helicity, are largely insensitive to geometry, even when the geometry creates direct channels through the pack bed orientated along the gradient in applied pressure. For steady flows and strongly turbulent flows, such channels are predicted to provide direct routes for dispersion through a packed bed, while for weakly turbulent flows they influence dispersion primarily by destabilizing the flow and thereby promoting dispersion throughout a bed. The dispersion of tracer-particles released from a source located on or close to a ``stagnation streamline'' is predicted to be faster than ballistic in the near field and the transition to long-time Fickian diffusion is predicted to be distinguished by a regime of subdiffusion.

  13. Effect of secondary air injection on the combustion efficiency of sawdust in a fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    K. V. N. Srinivasa Rao

    2008-03-01

    Full Text Available Agricultural wastes like bagasse, paddy husks, sawdust and groundnut shells can be effectively used as fuels for fluidized bed combustion; otherwise these biomass fuels are difficult to handle due to high moisture and fines content. In the present work the possibility of using sawdust in the fluidized bed combustor, related combustion efficiencies and problems encountered in the combustion process are discussed. The temperature profiles for sawdust with an increase in fluidizing velocity along the vertical height above the distributor plate indicate that considerable burning of fuel particles is taking place in the freeboard zone rather than complete burning within the bed. Therefore, an enlarged disengagement section is provided to improve the combustion of fines. The temperature profiles along the bed height are observed at different feed rates. The feed rate of sawdust corresponding to the maximum possible temperature was observed to be 10.2 kg/h. It is observed that 50-60% excess air is optimal for reducing carbon loss during the burning of sawdust. The maximum possible combustion efficiency with sawdust is 99.2% and is observed with 65% excess air.

  14. DEM坡度的尺度效应研究%The study on scale effect of DEM slope

    Institute of Scientific and Technical Information of China (English)

    白天路; 申佳

    2012-01-01

    DEM的坡度是地形分析中的重要地理因子,随着DEM分辨率的降低,在其上提取的坡度会不断趋于平缓,因而不能如实表现地形起伏。本文重点研究了制图综合和采样间隔两个方面对DEM坡度的影响,利用不同分辨率DEM所提取的坡度的频率和累计频率,并对其进行分级统计,作为数据分析基础。利用制图综合和采样间隔两方面的综合效应对DEM坡度的影响,验证了DEM坡度随其分辨率的降低而发生衰减。针对制图综合生成的DEM具有相同的栅格尺寸,不同的综合平滑度,而不同采样间隔地形图生成的DEM具有相同的综合平滑程度、不同的栅格大小和不同的信息量,对这两种情况下的DEM坡度分别进行了统计分析,结果表明制图综合对1:25万地形图生成DEM坡度的影响较大,对于其他比例尺地形图生成DEM的坡度衰减影响不明显。采样间隔对于1:1万比例尺地形图生成不同分辨率DEM的坡度衰减都具有较大影响。%DEM slope decreases along with the reduction of spatial resolution. For the purpose of investigating the attenuation of DEM slope caused by cartographic generalization and changes of sampling interval, taking Xiannangou Catchment in Ansai Shaanxi as an example, the slopes of DEM generated by 1:1000, 1:5000, 1:10000 and 1:250000 topographic digital maps are compared. After statistical analysis, we find that DEM mean slope decreased by the combined effects of cartographic generalization and sampling interval, and slope frequency concentrated in the gradient of the narrower ranges. Furthermore, cartographic generalization has greater impact on DEM slope of 1:25 million map, and sampling interval has a greater effect on the DEM slopes of all scale maps generated by 1:10000 map.

  15. Effect of work of adhesion on deep bed filtration process

    Science.gov (United States)

    Przekop, Rafał; Jackiewicz, Anna; WoŻniak, Michał; Gradoń, Leon

    2016-06-01

    Collection of aerosol particles in the particular steps of the technology of their production, and purification of the air at the workplace and atmospheric environment, requires the efficient method of separation of particulate matter from the carrier gas. There are many papers published in last few years in which the deposition of particles on fibrous collectors is considered, Most of them assume that collisions between particle and collector surface is 100% effective. In this work we study the influence of particles and fiber properties on the deposition efficiency. For the purpose of this work the lattice-Boltzmann model describes fluid dynamics, while the solid particle motion is modeled by the Brownian dynamics. The interactions between particles and surface are modelled using energy balanced oscillatory model. The work of adhesion was estimated using Atomic Force Microscopy.

  16. Effectiveness of Mutual Learning Approach in the Academic Achievement of B.Ed Students in Learning Optional II English

    Science.gov (United States)

    Arulselvi, Evangelin

    2013-01-01

    The present study aims at finding out the effectiveness of Mutual learning approach over the conventional method in learning English optional II among B.Ed students. The randomized pre-test, post test, control group and experimental group design was employed. The B.Ed students of the same college formed the control and experimental groups. Each…

  17. In-Situ Low-Angle Cross Sectioning: Bevel Slope Flattening due to Self-Alignment Effects

    OpenAIRE

    Scheithauer, Uwe

    2015-01-01

    Low-angle cross sections are produced inside an Auger microprobe using the equipped depth profile ion sputter gun. Simply the sample is partly covered by a mask. Utilizing the edge of this mask the sample is sputtered with ions. Due to the shading of the mask a cross section is produced in the sample. The slope of this cross section is considerably shallower than given by the geometrical setup. This is attributed to self-alignment effects, which are due to missing sputter cascades in the tran...

  18. Effects of induced inter-bedded shale breakage on SAGD performance in the Orinoco belt

    Energy Technology Data Exchange (ETDEWEB)

    Bashbush, J.L.; Fernandez, E.; Rodriguez, A.; Pina, J.A.; Ruiz, J. [Schlumberger, Piso (Venezuela, Bolivarian Republic of)

    2009-07-01

    Venezuela's Orinoco oil belt (Faja) which covers an area of 13 MM acres is being developed using primary recovery techniques that render recovery factors below 6 per cent. The national oil and gas company Petroleos de Venezuela SA is seeking to increase recovery factors to at least 20 per cent. Sandshale sequences in the oil belt vary from a few feet thick to hydrocarbon impregnated sand packages of 100 feet or more. Shales act as barriers to vertical flow and have to be considered when selecting an enhanced recovery mechanism to increase the recovery factor. This study assessed the effect of having inter-bedded shales in 2 possible scenarios for steam assisted gravity drainage (SAGD), namely as permanent barriers or as temporary barriers amenable to be breakage as a function of temperature and thickness; and comparing steam chamber generation/propagation and its impact on production in the model before and after a potentially induced shale bed breach as a response to the thermal stresses during a SAGD process. Steam condensation will generate fresh water which can produce shale swelling and a change in permeability of the shales. This paper presented a numerical simulation study analyzing the behavior of a series of shale beds lamination schemes in a 100-foot reservoir. Recovery was compared by considering the shales as permanent barriers to vertical flow and the potential generation of flow paths of varying conductivities through the thinner shale beds as a function of thermal stress, length of exposure to steam and its condensate and pressure differentials. The study showed that breaching the vertical seals to allow flow through inter-bedded shales and shale stringers will increase the oil production rates and the recovery factors for the Faja type reservoir. 8 refs., 3 tabs., 16 figs.

  19. Effect of Soil Erosion on Soil Properties and Crop Yields on Slopes in the Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    SU Zheng-An; ZHANG Jian-Hui; NIE Xiao-Jun

    2010-01-01

    Roles of tillage erosion and water erosion in the development of within-field spatial variation of surface soil properties and soil degradation and their contributions to the reduction of crop yields were studied on three linear slopes in the Sichuan Basin,southwestern China.Tillage erosion was found to be the dominant erosion process at upper slope positions of each linear slope and on the whole short slope (20 m).On the long slope (110 m) and medium slope (40 m),watererosion was the dominant erosion process.Soil organic matter and soil nutrients in the tillage layer were significantly related to slope length and 137Cs inventories on the long slope;however,there was no significant correlation among themon the short slope,suggesting that water erosion lowered soil quality by transporting SOM and surface soil nutrients selectively from the upper to lower slope positions,while tillage erosion transported soil materials unselectively.On the medium slope,SOM,total N,and available N in the tillage layer were correlated with slope length and the other properties were distributed evenly on the slope,indicating that water erosion on this slope was still the dominant soil redistribution process.Similar patterns were found for the responses of grain yield,aboveground biomaas,and harvest index for slopes.These results indicated that tillage erosion was a major cause for soil degradation and grain yield reduction on the linear slopes because it resulted in displacement of the tillage layer soil required for maintaining soil quality and plant growth.

  20. Effects of gravel on infiltration, runoff, and sediment yield in landslide deposit slope in Wenchuan earthquake area, China.

    Science.gov (United States)

    Li, Tianyang; He, Binghui; Chen, Zhanpeng; Zhang, Yi; Liang, Chuan; Wang, Renxin

    2016-06-01

    Amounts of landslide deposits were triggered by the Wenchuan earthquake with magnitude 8.0 on May 12, 2008. The landslide deposits were composed of soil and rock fragments, which play important roles in hydrological and erosion processes in the steep slope of landslide deposits. The mixtures of soil and gravels are common in the top layers of landslide deposits, and its processes are obviously different with the soil without gravels. Based on the data of field investigation, a series of simulated scouring flow experiments with four proportion of gravel (0, 25, 33.3, and 50 %) and three scouring flow rates (4, 8, 12 L/min) under two steep slopes (67.5, 72.7 %) were conducted sequentially to know the effects of proportion of gravel on infiltration capacity, runoff generation, and sediment production in the steep slope of landslide deposit. Results indicated that gravel had promoted or reduced effects on infiltration capacity which could affect further the cumulative runoff volume and cumulative sediment mass increase or decrease. The cumulative infiltration volume in 25 % proportion of gravel was less than those in 0, 33.3, and 50 % proportion of gravel. The cumulative runoff volume was in an order of 25 > 0 > 33.3 > 50 % while cumulative sediment mass ranked as 25 > 33.3 > 0 > 50 % with different proportions of gravel. A significant power relationship was found between scouring time and cumulative runoff volume as well as cumulative sediment mass. The relationship between average soil and water loss rate and proportion of gravel was able to express by quadratic function, with a high degree of reliability. The results have important implications for soil and water conservation and modeling in landslide deposit but also provide useful information for the similar conditions. PMID:26965277

  1. Climbing Ability of the Common Bed Bug (Hemiptera: Cimicidae).

    Science.gov (United States)

    Hottel, B A; Pereira, R M; Gezan, S A; Qing, R; Sigmund, W M; Koehler, P G

    2015-05-01

    Little is known about what factors influence the climbing ability of bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae), in relation to the various surfaces they encounter. We examined how sex, time since last fed, and what surfaces the bed bugs were in contact with affected their climbing performance. The effects of sex and time since fed were tested by counting the number of bed bugs able to climb a 45° slope. The pulling force was recorded using an analytical balance technique that captured the sequential vertical pulling force output of bed bugs attached to various surfaces. Recently fed female bed bugs were found to have the most difficulty in climbing smooth surfaces in comparison with males. This difference can be explained by the larger weight gained from bloodmeals by female bed bugs. A variety of vertical pulling forces were observed on surfaces ranging from sandpaper to talc powder-covered glass. For surfaces not treated with talc powder, bed bugs generated the least amount of vertical pulling force from synthetically created 0.6-µm plastron surfaces. This vast range in the ability of bed bugs to grip onto various surfaces may have implications on limiting bed bugs dispersal and hitchhiking behaviors. PMID:26334801

  2. Experimental Investigation of Effects of Vibration upon Elastic and Cohesive Properties of Beds of Wet Sand

    Directory of Open Access Journals (Sweden)

    S. Alsop

    1995-01-01

    Full Text Available The transmission of sinusoidal vibrations through beds of cohesive particulate solids was measured. Results were interpreted in terms of a critical state model to predict the elastic swelling constant k, and the cohesive stress C. Factorial experimental design was used to identify significant parameters. Factors that affect k include percent moisture, bulk density, sample size, sample shape, the presence of a supporting membrane, and loading order. Factors that affect C include percent moisture and particle size distribution. Factors affecting k were interpreted in terms of their effects upon bed structure and factors affecting C in terms of an equivalent pore water pressure due to capillary and liquid bridge effects. The critical state model was modified to incorporate general relationships between axial and radial strains.

  3. Effect of delivery condition on desorption rate of ZrCo metal hydride bed for fusion fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Kang, H.G.; Yun, S.H.; Chung, D.; Oh, Y.H.; Chang, M.H.; Cho, S. [National Fusion Research Institute, Daejeon (Korea, Republic of); Chung, H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Song, K.M. [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2015-03-15

    For the safety of fusion fuel cycle, hydrogen isotope gases including tritium are stored as metal hydride form. To satisfy fueling requirement of fusion machine, rapid delivery from metal hydride bed is one of major factors for the development of tritium storage and delivery system. Desorption from metal hydride depends on the operation scenario by pressure and temperature control of the bed. The effect of operation scenario and pump performance on desorption rate of metal hydride bed was experimentally investigated using ZrCo bed. The results showed that the condition of pre-heating scenario before actual delivery of gas affected the delivery performance. Different pumps were connected to desorption line from bed and the effect of pump capacity on desorption rate were also found to be significant. (authors)

  4. The effect of interparticle cohesive forces on the simulation of fluid flow in spout-fluid beds

    Directory of Open Access Journals (Sweden)

    Trindade A. L. G.

    2004-01-01

    Full Text Available As reflected in the literature, solid-fluid flow characteristics in spouted beds can vary widely when particles are coated by a suspension. This work is aimed at describing the effect of interparticle forces on airflow distribution in conical spouted beds of inert particles coated by Eucalyptus black liquor. The simulator developed earlier is modified to incorporate this effect. Two corrective functions with adjustable parameters are introduced into the simulator gas-flow model to generate the minimum spouting conditions in beds wetted by this liquor. These functions are assumed to be dependent on characteristic suspension groups and bed height. Using the particle swarm optimization (PSO technique, expressions for these functions are obtained. Simulated results are presented and discussed to validate this technique. Implications of these results on drying Eucalyptus black liquor in conical spouted beds are analyzed.

  5. Determinations of effective heat transport coefficients for wall-cooled packed beds

    OpenAIRE

    Borkink, J.G.H.; Westerterp, K.R.

    1992-01-01

    The influence is studied of several assumptions, often made in literature, on the values for the effective radial heat conductivity, wall heat transfer coefficient and overall heat transfer coefficient, as obtained from experiments in wall-cooled packed beds without a chemical reaction. Especially the choice of the inlet boundary condition can have a large impact on the values obtained. The influence of the presence of a radial velocity profile and also the cross-correlation of the parameters...

  6. The study on fuel effect in discharge pipe of pebble bed reactor

    International Nuclear Information System (INIS)

    The simulation method of fuel loading in discharge pipe of pebble bed reactor is introduced. As an exemplary application case, the effect of fuel elements in the discharge pipe on reactor physics and thermohydraulic properties is calculated and analysed by CHTRP code in HTR-10 MW. The calculation gives the power and temperature distribution in the area of the discharge pipe, very useful for further analysis of reactor physics and safety

  7. Two-Phase Flow Effect on the Ex-Vessel Corium Debris Bed Formation in Severe Accident

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eunho; Park, Jin Ho; Kim, Moo Hwan; Park, Hyun Sun [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of); Ma, Weimin; Bechta, Sevostian V. [Royal Institute of Technology, Stockholm (Sweden)

    2014-05-15

    In Korean IVR-ERVC(In-Vessel Retention of molten corium through External Reactor Vessel Cooling) strategy, if the situation degenerates into insufficient external vessel cooling, the molten core mixture can directly erupt into the flooded cavity pool from the weakest point of the vessel. Then, FCI (molten Fuel Coolant Interaction) will fragment the corium jet into small particulates settling down to make porous debris bed on the cavity basemat. To secure the containment integrity against the MCCI (Molten Core - Concrete Interaction), cooling of the heat generating porous corium debris bed is essential and it depends on the characteristics of the bed itself. For the characteristics of corium debris bed, many previous experimental studies with simulant melts reported the heap-like shape mostly. There were also following experiments to develop the correlation for the heap-like shaped debris bed. However, recent studies started to consider the effect of the decay heat and reported some noticeable results with the two-phase flow effect on the debris bed formation. The Kyushu University and JAEA group reported the experimental studies on the 'self-leveling' effect which is the flattening effect of the particulate bed by the inside gas generation. The DECOSIM simulation study of RIT (Royal Institute of Technology, Sweden) with Russian researchers showed the 'large cavity pool convection' effect, which is driven by the up-rising gas bubble flow from the pre-settled debris bed, on the particle settling trajectories and ultimately final bed shape. The objective of this study is verification of the two-phase flow effect on the ex-vessel corium debris bed formation in the severe accident. From the analysis on the test movie and resultant particle beds, the two-phase flow effect on the debris bed formation, which has been reported in the previous studies, was verified and the additional findings were also suggested. For the first, in quiescent pool the

  8. ElevationSlope_SLOPE2M

    Data.gov (United States)

    Vermont Center for Geographic Information — This metadata applies to the following collection area(s): Bennington County 2012 2.0m and related SLOPE datasets. Created using ArcGIS "SLOPE" command to produce...

  9. Effect of Faulting on Ordovician Carbonate Buried-Hill Reservoir Beds in Hetianhe Gas Field,Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    Lü Xiuxiang; Bai Zhongkai; Li Jianjiao; Wang Weiguang; Fu Hui; Wang Qinghua

    2008-01-01

    Ordovician carbonate buried-hill reservoir beds in the Hetianhe (和田河) gas field,located in the Mazhatage (玛扎塔格) structural belt on the southern margin of the Bachu (巴楚) faulted uplift,southwestern Tarim basin,were studied.Based on field survey,core and slice observation,the general characteristics of carbonate buried-hill reservoir beds and specifically Ordovician carbonate buried-hill reservoir beds in the Hetianhe gas field were discussed.The karst zone of the reservoir beds in Hetianhe gas field was divided into superficial karst zone,vertical infiltration karst zone,lower subsurface flow karst zone,and deep sluggish flow zone from top to bottom.The effects of faulting on Ordovician carbonate buried-hill reservoir beds in the Hetianhe gas field were obvious.The faulting intensified the karstification and increased the depth of denudation.Faulting and subsequent fracture growth modified the reservoir beds and improved the physical property and quality of the reservoir beds.Moreover,faulting enhanced the development of the dissolution holes and fractures and increased the thickness of the effective reservoir beds.Meanwhile,faulting made the high porosity-permeability carbonate belts,which created conditions for the hydrocarbon accumulation,develop near the fault zone.

  10. Effects of magnetic fields on improving mass transfer in flue gas desulfurization using a fluidized bed

    Science.gov (United States)

    Zhang, Qi; Gui, Keting; Wang, Xiaobo

    2016-02-01

    The effects of magnetic fields on improving the mass transfer in flue gas desulfurization using a fluidized bed are investigated in the paper. In this research, the magnetically fluidized bed (MFB) is used as the reactor in which ferromagnetic particles are fluidized with simulated flue gas under the influence of an external magnetic field. Lime slurry is continuously sprayed into the reactor. As a consequence, the desulfurization reaction and the slurry drying process take place simultaneously in the MFB. In this paper, the effects of ferromagnetic particles and external magnetic fields on the desulphurization efficiency are studied and compared with that of quartz particles as the fluidized particles. Experimental results show that the ferromagnetic particles not only act as a platform for lime slurry to precipitate on like quartz particles, but also take part in the desulfurization reaction. The results also show that the specific surface area of ferromagnetic particles after reaction is enlarged as the magnetic intensity increases, and the external magnetic field promotes the oxidation of S(IV), improving the mass transfer between sulphur and its sorbent. Hence, the efficiency of desulphurization under the effects of external magnetic fields is higher than that in general fluidized beds.

  11. Experimental Investigation of climate change effects on plant available water on rocky desert slopes

    Science.gov (United States)

    Kuhn, Nikolaus; Hikel, H.; Schwanghart, W.; Yair, Aaron

    2010-05-01

    Deserts and semi-deserts cover more than one-third of the global land surface, affecting about 49 million km2 with aridity. In many arid regions, slopes are characterized by sparse and patchy soil and vegetation cover, forming so called 'fertility islands'. The mosaic of soil and vegetation is dynamically interdependent, controlled by adaption of the ecosystem to limited and spatially as well as temporarily variable precipitation. Commonly, the role of the pattern of rocks and soil is considered to act as a natural water harvesting system. In an ideal system, the rocky area supplying water matches the soil's infiltration capacity for the given rainfall magnitude. This approach limits the assessment of plant water supply to the amount and intensity of rainfall events, i.e. the supply of water. In reality, the demand of water by the plants also requires consideration. Therefore, the volume of soil storing water is equally important to the ration of soil to rock. Soil volume determines the absolute amount of water stored in the soil and is thus indicative of the time period during which plants do not experience drought related stress between rainfall events. With climate change likely affecting the temporal pattern of rainfall events, a detailed understanding of soil-water interaction, including the storage capacity of patchy soils on rocky slopes, is required. The aim of the study is to examine the relationship between climate change and plant available water on patchy soils in the Negev desert. Thirteen micro-catchments near Sede Boqer were examined. For each micro-catchment, soil volume and distribution was estimated by laser scanning before and after soil excavation. Porosity was estimated by weighing the excavated soil. Before excavation, sprinkling experiments were conducted. Rainfall of 18mm/h was applied to an area of 1m2 each. The experiments lasted 25 to 40 minutes, until equilibrium runoff rates were achieved. Based on these data, rainfall required for soil

  12. Effect of Wetting and Contamination of Granular Beds During Sphere Impact

    KAUST Repository

    Kouraytem, Nadia

    2013-03-01

    This thesis presents results from an experimental study of the impact of dense solid spheres onto granular beds. The overall aim is to further our understanding of the dynamical response of granular materials to impact. In order to do this, we will study both the initial penetration stages and peak acceleration exerted on the sphere by using high-speed imaging. Another critical part is to measure the penetration depth of the sphere and calculate the corresponding depth-averaged stopping force. Both of these main focal points will be assessed for not only dry, but wet and “contaminated” grains, whereby the granular bed will be comprised of two distinct size ranges of base grains. In doing so, we aim to broadly determine whether contaminated grains or wet grains are more effective at increasing the tensile strength of granular materials.

  13. Effects of operating conditions on the removal of heavy metals by zeolite in fixed bed reactors

    International Nuclear Information System (INIS)

    This work investigates the effects of flow rate (5-15 Bed Volumes/h), particle size (0.8-1.7 mm), concentration (0.005-0.02 N) and Na+-enrichment of natural clinoptilolite on the removal efficiency of Pb2+, Cu2+, Fe3+ and Cr3+ in aqueous solutions. Ion exchange is performed in an upflow fixed bed reactor. The removal efficiency is increased with decreasing flow rate, particle size and concentration and is improved by a factor of 2-10, depending on the specific metal. The modification of the natural sample is favorable, leading to an increase of removal efficiency by 32-100%. For the experimental conditions examined, removal efficiency order is the following: Pb2+>Cr3+>Fe3+≥Cu2+. Finally, the operation is influenced by the studied parameters, following the order: concentration>volumetric flow rate>particle size>modification of the material

  14. Effects of Spatial Variations in Packing Fraction on Reactor Physics Parameters in Pebble-Bed Reactors

    International Nuclear Information System (INIS)

    The well-known spatial variation of packing fraction near the outer boundary of a pebble-bed reactor core is cited. The ramifications of this variation are explored with the MCNP computer code. It is found that the variation has negligible effects on the global reactor physics parameters extracted from the MCNP calculations for use in analysis by diffusion-theory codes, but for local reaction rates the effects of the variation are naturally important. Included is some preliminary work in using first-order perturbation theory for estimating the effect of the spatial variation of packing fraction on the core eigenvalue and the fision density distribution

  15. Effects of Spatial Variations in Packing Fraction of Reactor Physics Parameters in Pebble-Bed Reactors

    International Nuclear Information System (INIS)

    The well-known spatial variation of packing fraction near the outer boundary of a pebble-bed reactor core is cited. The ramifications of this variation are explored with the MCNP computer code. It is found that the variation has negligible effects on the global reactor physics parameters extracted from the MCNP calculations for use in analysis by diffusion-theory codes, but for local reaction rates the effects of the variation are naturally important. Included is some preliminary work in using first-order perturbation theory for estimating the effect of the spatial variation of packing fraction on the core eigenvalue and the fission density distribution

  16. Effects of Spatial Variations in Packing Fraction on Reactor Physics Parameters in Pebble-Bed Reactors

    Energy Technology Data Exchange (ETDEWEB)

    William K. Terry; A. M. Ougouag; Farzad Rahnema; Michael Scott McKinley

    2003-04-01

    The well-known spatial variation of packing fraction near the outer boundary of a pebble-bed reactor core is cited. The ramifications of this variation are explored with the MCNP computer code. It is found that the variation has negligible effects on the global reactor physics parameters extracted from the MCNP calculations for use in analysis by diffusion-theory codes, but for local reaction rates the effects of the variation are naturally important. Included is some preliminary work in using first-order perturbation theory for estimating the effect of the spatial variation of packing fraction on the core eigenvalue and the fision density distribution.

  17. Effects of Bahia Grass Cover and Mulch on Runoff and Sediment Yield of Sloping Red Soil in Southern China

    Institute of Scientific and Technical Information of China (English)

    LI Xin-Hu; ZHANG Zhan-Yu; YANG Jie; ZHANG Guo-Hua; WANG Bin

    2011-01-01

    Rainfall, runoff (surface runoff, interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover, mulch and bare ground) on sloping red soil in southern China. Surface runoff and erosion from the Bahia grass (Paspalum notatum Flugge) cover plot (A) and mulch plot (B) during the 5 years were low,despite the occurrence of potentially erosive rains. In contrast, the bare plot (C) had both the highest surface runoff coefficient and the highest sediment yield. There were significant differences in interflow and surface runoff and no significant difference in groundwater runoff among plots. The runoff coefficients and duration of interflow and groundwater runoff were in the order plot B > plot A > plot C. Effects of Bahia grass cover were excellent, indicating that the use of Bahia grass cover can be a simple and feasible practice for soil and water conservation on sloping red soil in the region.

  18. Post-fire Vegetation regeneration effects on runoff and sediment yield: slope, aspect and fire severityPost-fire Vegetation regeneration effects on runoff and sediment yield: slope, aspect and fire severity

    Science.gov (United States)

    Barzilai, R.; Wittenberg, L.; Malkinson, D.

    2009-04-01

    1 Post-fire Vegetation regeneration effects on runoff and sediment yield: slope, aspect and fire severity During the last several decades fire occurrence at the Carmel Mountain ridge has been increasing, showing similar trends to the ones observed in the Mediterranean basin. Wildfires damage and destroy the vegetation and therefore alter the components of the eco-geomorphic system, which leads to an increase in runoff and sediment yields. In April, 2005 a wildfire consuming 154 ha of planted and natural vegetation occurred at the north-western part of the Carmel ridge. Following the event, a 2x2x2 factorial design of monitoring plots was established to examine the relationship between vegetation recovery, runoff and sediment yield. Namely, slope aspect, slope steepness and fire severity were specifically examined in relation to the above mentioned response variables. The research methods included (a) the establishment of 14 plots of ~ 10.5m2 each, designed for runoff and sediment collection and for monitoring vegetation cover change. (b) Monthly aerial photography of the research plots using a pole-mounted camera. The images were digitally classified to identify rock cover, vegetation cover, and bare soil patches. The time dependent vegetation regeneration was used for assessing landscape recovery. (c) Collection of runoff and sediment yield after each rain event. Multiple regression analysis was conducted in order to determine the relative importance of land cover classes and different precipitation parameters on runoff and sediment yield. Vegetation recovery rates during the first wet season were relatively low; by the end of the first spring season vegetation cover reached 30%-35%. During the first summer, a year after the fire, there was a slight decrease in vegetation cover, due to the die off of the annual herbaceous vegetation. In the second winter vegetation cover continued to increase, and by the end of the research period (summer 2007) average vegetation

  19. Effect of wall structure on pebble stagnation behavior in pebble bed reactor

    International Nuclear Information System (INIS)

    Highlights: • DEM study of wall structure role in preventing near wall crystallization is carried out. • Suggestions on pebble’s kinematic parameters and wall structure design are provided. • Triangle is better than arc and sawtooth shapes for wall structure design. • Wall structure size should be close to the scale of pebble diameter. • Suitable intervals can prevent crystallization without significantly increasing the flow resistance. - Abstract: Crystallization of pebbles in pebble bed is a crucial problem in high temperature gas-cooled pebble-bed reactors. This phenomenon usually happens along the internal surface and leads to a large number of stagnated pebbles, which poses a threat to reactor safety. In real reactor engineering, wall structures have been utilized to avoid this problem. This article verifies the crystallization phenomenon through DEM (discrete element method) simulation, and explains how wall structures work in preventing crystallization. Moreover, several kinematic parameters have been adopted to evaluate wall structures with different shapes, sizes and intervals. Detailed information shows the impact of wall structure on flow field in pebble bed. Lastly, the preferred characteristics of an effective wall structure are suggested for reactor engineering

  20. The effect of coal-bed methane water on spearmint and peppermint.

    Science.gov (United States)

    Zheljazkov, Valtcho D; Cantrell, Charles L; Astatkie, Tess; Schlegel, Vicki; Jeliazkova, Ekaterina; Lowe, Derek

    2013-11-01

    Coal bed methane is extracted from underground coal seams that are flooded with water. To reduce the pressure and to release the methane, the water needs to be pumped out. The resulting waste water is known as coal bed methane water (CBMW). Major concerns with the use of CBMW are its high concentrations of S, Na, dissolved Ca, Mg, SO, and bicarbonate (HCO). Irrigation water is a scarce resource in most of the western states. The objective of this study was to evaluate the effect of various amounts of CBMW on the growth, essential oil content, composition, and antioxidant activity of spearmint ( L.) and peppermint ( L.) crops that were irrigated with the water. These two crops are grown in some western states and are potential specialty crops to Wyoming farmers. The irrigation treatments were 0% CBMW (tap water only), 25% CBMW (25% CBMW plus 75% tap water), 50% CBMW (50% CBMW and 50% tap water), 75% CBMW (75% CBMW plus 25% tap water), and 100% CBMW. Analyses of the data revealed that the CBMW treatments did not affect the antioxidant capacity of spearmint or peppermint oil (242 and 377 μmol L Trolox g, respectively) or their major oil constituents (carvone or menthol). Coal bed methane water at 100% increased total phenols and total flavonoids in spearmint but not in peppermint. Coal bed methane water also affected oil content in peppermint but not in spearmint. Spearmint and peppermint could be watered with CBMW at 50% without suppression of fresh herbage yields. However, CBMW at 75 and 100% reduced fresh herbage yields of both crops and oil yields of peppermint relative to the control. PMID:25602421

  1. Effectiveness of Comprehensive Nursing Care Relieving Problems of Hospitalized High-Risk Pregnant Women in Bed Rest

    OpenAIRE

    Umran Yesiltepe Oskay; Anahit Coskun

    2012-01-01

    It is well known that bed rest at home or in hospital has many physical and psychosocial effects on pregnant women. Objective: This study is type of an intervention study which has been conducted to determine bed rest related physical and psychosocial problems of hospitalized high-risk pregnant women and effectiveness of a comprehensive nursing care plan in solving to those problems. Material and Method: The sample group was selected among high-risk pregnant women who were hospitalized in per...

  2. The effect of interparticle cohesive forces on the simulation of fluid flow in spout-fluid beds

    OpenAIRE

    A. L. G. Trindade; PASSOS M. L.; E. F. Costa Jr; E. C. Biscaia Jr

    2004-01-01

    As reflected in the literature, solid-fluid flow characteristics in spouted beds can vary widely when particles are coated by a suspension. This work is aimed at describing the effect of interparticle forces on airflow distribution in conical spouted beds of inert particles coated by Eucalyptus black liquor. The simulator developed earlier is modified to incorporate this effect. Two corrective functions with adjustable parameters are introduced into the simulator gas-flow model to generate th...

  3. Mortality, temporary sterilization, and maternal effects of sublethal heat in bed bugs

    OpenAIRE

    Rukke, Bjørn Arne; Aak, Anders; Edgar, Kristin Skarsfjord

    2015-01-01

    Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40...

  4. Exercise Effects on the Brain and Sensorimotor Function in Bed Rest

    Science.gov (United States)

    Koppelmans, V.; Cassady, K.; De Dios, Y. E.; Szecsy, D.; Gadd, N.; Wood, S. J.; Reuter-Lorenz, R. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.; Ploutz-Snyder, L.; Seidler, R. D.

    2016-01-01

    Long duration spaceflight microgravity results in cephalad fluid shifts and deficits in posture control and locomotion. Effects of microgravity on sensorimotor function have been investigated on Earth using head down tilt bed rest (HDBR). HDBR serves as a spaceflight analogue because it mimics microgravity in body unloading and bodily fluid shifts. Preliminary results from our prior 70 days HDBR studies showed that HDBR is associated with focal gray matter (GM) changes and gait and balance deficits, as well as changes in brain functional connectivity. In consideration of the health and performance of crewmembers we investigated whether exercise reduces the effects of HDBR on GM, functional connectivity, and motor performance. Numerous studies have shown beneficial effects of exercise on brain health. We therefore hypothesized that an exercise intervention during HDBR could potentially mitigate the effects of HDBR on the central nervous system. Eighteen subjects were assessed before (12 and 7 days), during (7, 30, and 70 days) and after (8 and 12 days) 70 days of 6-degrees HDBR at the NASA HDBR facility in UTMB, Galveston, TX, US. Each subject was randomly assigned to a control group or one of two exercise groups. Exercise consisted of daily supine exercise which started 20 days before the start of HDBR. The exercise subjects participated either in regular aerobic and resistance exercise (e.g. squat, heel raise, leg press, cycling and treadmill running), or aerobic and resistance exercise using a flywheel apparatus (rowing). Aerobic and resistance exercise intensity in both groups was similar, which is why we collapsed the two exercise groups for the current experiment. During each time point T1-weighted MRI scans and resting state functional connectivity scans were obtained using a 3T Siemens scanner. Focal changes over time in GM density were assessed using voxel based morphometry (VBM8) under SPM. Changes in resting state functional connectivity was assessed

  5. The Effects of Dinner-to-Bed Time and Post-Dinner Walk on Gastric Cancer Across Different Age Groups

    Science.gov (United States)

    Xu, Le; Zhang, Xi; Lu, Jun; Dai, Jia-Xi; Lin, Ren-Qin; Tian, Fang-Xi; Liang, Bing; Guo, Yi-Nan; Luo, Hui-Yu; Li, Ni; Fang, Dong-Ping; Zhao, Ruo-Hua; Huang, Chang-Ming

    2016-01-01

    Abstract Gastric cancer (GC) remains a major killer throughout the world. Despite the dramatic decrease in GC over the last century, its etiology has not yet been well characterized. This study investigated the possible independent and combined effects of the dinner-to-bed time and post-dinner walk on the risk for GC across different age groups. A population-based, case–control study was conducted in southeast China, including 452 patients with GC and 465 age-, race-, and gender-matched controls. A self-designed questionnaire was used to collect information on demographic characteristics, dinner-to-bed time, post-dinner walk, and other behavioral factors. Conditional logistic regression models were used to estimate the effects of the dinner-to-bed time and post-dinner walk as well as their joint effect on the risk for GC across different age groups. Individuals with dinner-to-bed time 55 years old. PMID:27100427

  6. Stability Assessment and Optimization Design of Lakeside Open-Pit Slope considering Fluid-Solid Coupling Effect

    OpenAIRE

    Wenchen Fan; Ping Cao; Ke Zhang; Kaihui Li; Chong Chen

    2015-01-01

    Chengmenshan copper mine, located at Jiujiang city in the Jiangxi Province, is a rarely lakeside open-pit mine in China. Since the open-pit is very close to Sai Lake, the seasonally changed water level and the distance between lake and slope have great influence to the stability of open-pit slope. Based on the drill data and geological sections, a numerical model of the slope is built. With the fluid-mechanical interaction associated, the stability of the slopes is numerically analyzed, in wh...

  7. Mortality, temporary sterilization, and maternal effects of sublethal heat in bed bugs.

    Science.gov (United States)

    Rukke, Bjørn Arne; Aak, Anders; Edgar, Kristin Skarsfjord

    2015-01-01

    Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40 days after heat exposure, and the time until fertility was restored correlated with the temperature-sum experienced during heat exposure. Three or 6 days of parental exposure to 38.5°C significantly lowered their offspring's feeding and moulting ability, which consequently led to a failure to continue beyond the third instar. Eggs that were deposited at 22.0°C before being exposed to 37.0°C for 3 or 6 days died, whereas eggs that were exposed to lower temperatures were not significantly affected. Eggs that were deposited during heat treatment exhibited high levels of mortality also at 34.0°C and 35.5°C. The observed negative effects of temperatures between 34.0°C and 40.0°C may be utilized in pest management, and sublethal temperature exposure ought to be further investigated as an additional tool to decimate or potentially eradicate bed bug populations. The effect of parental heat exposure on progeny demonstrates the importance of including maternal considerations when studying bed bug environmental stress reactions. PMID:25996999

  8. Mortality, temporary sterilization, and maternal effects of sublethal heat in bed bugs.

    Directory of Open Access Journals (Sweden)

    Bjørn Arne Rukke

    Full Text Available Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40 days after heat exposure, and the time until fertility was restored correlated with the temperature-sum experienced during heat exposure. Three or 6 days of parental exposure to 38.5°C significantly lowered their offspring's feeding and moulting ability, which consequently led to a failure to continue beyond the third instar. Eggs that were deposited at 22.0°C before being exposed to 37.0°C for 3 or 6 days died, whereas eggs that were exposed to lower temperatures were not significantly affected. Eggs that were deposited during heat treatment exhibited high levels of mortality also at 34.0°C and 35.5°C. The observed negative effects of temperatures between 34.0°C and 40.0°C may be utilized in pest management, and sublethal temperature exposure ought to be further investigated as an additional tool to decimate or potentially eradicate bed bug populations. The effect of parental heat exposure on progeny demonstrates the importance of including maternal considerations when studying bed bug environmental stress reactions.

  9. Multi-System Effects of Daily Artificial Gravity Exposures in Humans Deconditioned by Bed Rest

    Science.gov (United States)

    Paloski, William H.

    2007-01-01

    We have begun to explore the utility of intermittent artificial gravity (AG) as a multi-system countermeasure to the untoward health and performance effects of adaptation to decreased gravity during prolonged space flight. The first study in this exploration was jointly designed by an international, multi-disciplinary team of scientists interested in standardizing an approach so that comparable data could be obtained from follow-on studies performed in multiple international locations. Fifteen rigorously screened male volunteers participated in the study after providing written informed consent. All were subjected to 21 days of 6deg head-down-tilt (HDT) bed rest. Eight were treated with daily 1hr AG exposures (2.5g at the feet decreasing to 1.0g at the heart) aboard a short radius (3m) centrifuge, while the other seven served as controls. Multiple observations were made of dependent measures in the bone, muscle, cardiovascular, sensory-motor, immune, and behavioral systems during a 10 day acclimatization period prior to HDT bed rest and again during an 8 day recovery period after the bed rest period. Comparisons between the treatment and control subjects demonstrated salutary effects of the AG exposure on aspects of the muscle and cardiovascular systems, with no untoward effects on the vestibular system, the immune system, or cognitive function. Bone deconditioning was similar between the treatment and control groups, suggesting that the loading provided by this specific AG paradigm was insufficient to protect that system from deconditioning. Future work will be devoted to varying the loading duty cycle and/or coupling the AG loading with exercise to provide maximum physiological protection across all systems. Testing will also be extended to female subjects. The results of this study suggest that intermittent AG could be an effective multi-system countermeasure.

  10. Benign Adjusting Effects of Long Tunnel on Environment and Slope Hazards: taking Erlang Mountain Tunnel as an example

    Institute of Scientific and Technical Information of China (English)

    WANG Quancai; WANG Lansheng; ZENG Lin; CHEN Yong

    2006-01-01

    The 21st century shall be a century of accelerated development of tunnel construction in China. But until now, what have been frequently stated in reports about influence of tunnels on environment are basically negative. In fact, this is not true. Tunnels, especially those extend across sensitive areas do exert some positive functions on improving environment and preventing local slope hazards. These positive effects, being new phenomena, are found and put forward by the authors after a series of careful observations have been carried out and in-depth analysis performed the first time. Meanwhile, it is a positive evaluation that the authors made upon tunnels. Many important phenomena and data are cited as evidence and their causative factors are analyzed in this paper as well.

  11. Effect of Wavelike Sloping Plate Rheocasting on Microstructures of Hypereutectic Al-18 pct Si-5 pct Fe Alloys

    Science.gov (United States)

    Guan, Ren-Guo; Zhao, Zhan-Yong; Lee, Chong Soo; Zhang, Qiu-Sheng; Liu, Chun-Ming

    2012-04-01

    To refine and spheroidize the microstructures of hypereutectic Al-Si-Fe alloys, a novel method of wavelike sloping plate (WSP) rheocasting was proposed, and the effect of the WSP rheocasting on the microstructures of hypereutectic Al-18 pct Si-5 pct Fe alloys was investigated. The results reveal that the morphologies of the primary Si crystal, the Al18Si10Fe5, and the Al8Si2Fe phases can be improved by the WSP rheocasting, and various phases tend to be refined and spheroidized with the decrease of the casting temperature. The alloy ingots with excellent microstructures can be obtained when the casting temperature is between 943 K and 953 K (670 °C and 680 °C). During the WSP rheocasting, the crystal nucleus multiplication, inhibited grain growth, and dendrite break-up take place simultaneously, which leads to grain refinement of the alloys.

  12. Performance Verification of the Lattice-type ECCS Sump Strainer to Prevent the Thin-bed effect

    International Nuclear Information System (INIS)

    In the event of a Loss of Coolant Accident (LOCA), a variety of debris could be generated under the post-LOCA conditions. The debris could block the Emergency Core Cooling System (ECCS) sump strainer, leading to a considerable head loss which in turn causes an abnormal ECCS and/or CS pump performance. The determination of strainer capacity is very important through the optimization of the head loss due to debris blockage. Especially, the thin-bed effect is a dominant factor to the design of the strainer. This paper presents experimental head loss data to confirm an advantage of an advanced lattice-type strainer for the thin-bed effect and is compared to the results of NUREG/CR-6224 head loss correlation. The thin-bed effect is a dominant design factor because the head loss could increase drastically by the lack of available voids in the debris bed for coolant to pass through it. Though this study, the lattice-type strainer to reduce or prevent the thin-bed effect has been designed. As the experimental data shows, there is no thin-bed effect in the present lattice-type strainer. It is expected that the required capacity of the strainer to maintain the function of ECCS will be significantly reduced by the lattice-type strainer of the present study

  13. Coal-Bed Methane Water Effects on Dill and Its Essential Oils.

    Science.gov (United States)

    Poudyal, Shital; Zheljazkov, Valtcho D; Cantrell, Charles L; Kelleners, Thijs

    2016-03-01

    Pumping water from coal seams decreases the pressure in the seam and in turn releases trapped methane; this is the most common and economic method of methane extraction. The water that is pumped out is known as "coal-bed methane water" (CBMW), which is high in sodium and other salts. In the past 25 yr, the United States has seen a 16-fold increase in the production of coal bed methane gas, and trillions of cubic meters are yet to be extracted. There is no sustainable disposal method for CBMW, and there are very few studies investigating the effects of this water on plants and their secondary metabolites and on soil properties. This study was conducted to determine the effects of CBMW on soil chemical properties and on the biomass and essential oil yield and composition of dill ( L.). This crop was grown in a greenhouse and was subjected to different levels of CBMW treatment: tap water only; 25% CBMW, 75% tap water; 50% CBMW, 50% tap water; 75% CBMW, 25% tap water; and 100% CBMW. The major dill oil constituents, limonene and α-phellandrene, were not affected by the treatments; however, the concentration of dill ether increased with increasing CBMW levels, whereas the concentration of carvone decreased. In soil, sodium level significantly increased with increasing level of treatment, but pH and cation exchange capacity were not much affected. Coal bed methane water could be used for irrigation of dill for one growing season, but longer-term studies may be needed to clarify the long-term effects on soil and plant. PMID:27065421

  14. The effect of DEM resolution on the computation of the factor of safety using an infinite slope model

    Science.gov (United States)

    Fuchs, Michael; Torizin, Jewgenij; Kühn, Friedrich

    2014-11-01

    The quality of digital elevation models (DEMs) is essential for reliable landslide susceptibility assessments. In this paper, two DEMs derived from ASTER (ASTER GDEM v.2 with 30 m horizontal resolution) and TerraSAR-X (GeoElevation10 with 10 m horizontal resolution) data are compared to study the effects of resolution on the derived slope and wetness index parameters in the application of the infinite slope model for the computation of the factor of safety. Several slope stability scenarios representing different wetness conditions with 5, 10 and 100 mm d- 1 of steady-state recharge were calculated for the eastern flank of Mount Rinjani Volcano on Lombok Island, Indonesia. Each scenario was conducted by computing the static factor of safety with mean values of the bulk density, angle of internal friction, cohesion, and failure depth parameters, as well as for their normally distributed values by Monte Carlo simulation. All scenarios were applied to both DEMs. The scenarios were evaluated by calculating the success/prediction rate using the respective area under the curve (AUC) and an existing landslide inventory. Additionally, uncertainties in the estimated positions of landslides were taken into account. Depending on the particular scenario, the success rate of the GeoElevation10 model shows differences up to 3% compared to the ASTER GDEM model. This apparent improvement is mainly caused by the higher ground resolution in GeoElevation10. However, the success rate increases for the 10 mm d- 1 and decreases for the 100 mm d- 1 steady-state recharge conditions. Consequently, the more detailed flow direction in the GeoElevation10 DEM has the highest impact under conditions with lower water saturation. The slight improvement in the total model quality shows that the higher resolution of the DEM has a small impact on poorly parameterized models, in which the material properties are described by roughly estimated parameters. Therefore, the application of a high

  15. Effect of cohesion on granular-fluid flows in spouted beds: PIV measurement and DEM simulations

    Science.gov (United States)

    Zhu, Runru; LI, Shuiqing; Yao, Qiang

    2013-06-01

    In contrast to wet granular flows, the effect of cohesion on complex granular-fluid flows is intriguing but much challenging. The liquid bridges, forming between binary particles with the addition of a small amount of liquids, might significantly change the granular-fluid system due to both cohesion and lubrication effects. In this paper, a spouted bed, among various fluidization technologies, is particularly selected as a prototypical system for studying granular-fluid flows, since it can provide a quasi-steady flow pattern of granular particles, i.e., a core of upward granular-fluid flow called the "spout" and a surrounding region of downward quasi-static granular flow called the "annulus". Firstly, using self-developed particle image velocimetery (PIV) technique, the effects of cohesion on the spout-annulus interface (namely the spout width) and on the particle velocity profiles in distinct zones are examined. Further, the discrete element method (DEM), by incorporating liquid bridge adhesion into soft-sphere model, is established and used to predict the microdynamic behavior of particles in spouted beds. Finally, based on both experiments and DEM validation, the effects on the granular patterns in these two zones are comparatively discussed.

  16. Experimental investigation of a draft tube spouted bed for effects of geometric parameters on operation

    Science.gov (United States)

    Azizaddini, Seyednezamaddin; Lin, Weigang; Dam-Johansen, Kim

    2016-06-01

    Experiments are performed in a draft tube spouted bed (DTSB) to investigate effects of the operating conditions and the geometric parameters on the hydrodynamics. Geometry parameters, such as heights of the entrained zone, draft tube inner diameter, inner angle of the conical section were studied. Increasing the draft tube inner diameter, sharper inner angle of the conical section and higher height of entrained zone increase the internal solid circulation rate and the pressure drop. Even though, for all different configurations, higher gas feeding rate leads to higher internal solid circulation rate considering a maximum value.

  17. Effect of packing fraction variations on reactivity in pebble-bed reactor

    International Nuclear Information System (INIS)

    The pebble-bed reactor (PBR) core consists of large number of randomly packed spherical fuel elements. The effect of fuel element packing density variations on multiplication factor in a typical PBR is studied using WIMS code. It is observed that at normal conditions the k-eff increases with packing fraction. Effects of secondary coolant ingress (water or molten lead) in the core at accidental conditions are studied at various packing densities. The effect of water ingress on reactivity depends strongly on water density and packing fraction and is prevailingly positive, while the lead ingress reduces multiplication factor regardless of lead effective density and packing fraction. Both effects are stronger at lower packing fractions. (author)

  18. Effects of continuous vs interval exercise training on oxygen uptake efficiency slope in patients with coronary artery disease

    Directory of Open Access Journals (Sweden)

    D.M.L. Prado

    2016-01-01

    Full Text Available The oxygen uptake efficiency slope (OUES is a submaximal index incorporating cardiovascular, peripheral, and pulmonary factors that determine the ventilatory response to exercise. The purpose of this study was to evaluate the effects of continuous exercise training and interval exercise training on the OUES in patients with coronary artery disease. Thirty-five patients (59.3±1.8 years old; 28 men, 7 women with coronary artery disease were randomly divided into two groups: continuous exercise training (n=18 and interval exercise training (n=17. All patients performed graded exercise tests with respiratory gas analysis before and 3 months after the exercise-training program to determine ventilatory anaerobic threshold (VAT, respiratory compensation point, and peak oxygen consumption (peak VO2. The OUES was assessed based on data from the second minute of exercise until exhaustion by calculating the slope of the linear relation between oxygen uptake and the logarithm of total ventilation. After the interventions, both groups showed increased aerobic fitness (P<0.05. In addition, both the continuous exercise and interval exercise training groups demonstrated an increase in OUES (P<0.05. Significant associations were observed in both groups: 1 continuous exercise training (OUES and peak VO2 r=0.57; OUES and VO2 VAT r=0.57; 2 interval exercise training (OUES and peak VO2 r=0.80; OUES and VO2 VAT r=0.67. Continuous and interval exercise training resulted in a similar increase in OUES among patients with coronary artery disease. These findings suggest that improvements in OUES among CAD patients after aerobic exercise training may be dependent on peripheral and central mechanisms.

  19. Effect of rock mass structure and block size on the slope stability--Physical modeling and discrete element simulation

    Institute of Scientific and Technical Information of China (English)

    LI; Shihai; LIAN; Zhenzhong; J.; G.; Wang

    2005-01-01

    This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

  20. Study on effective particle diameters and coolability of particulate beds packed with irregular multi-size particles

    International Nuclear Information System (INIS)

    One of the key questions in severe accident research is the coolability of the debris bed, i.e., whether decay heat can be completely removed by the coolant flow into the debris bed. Extensive experimental and analytical work has been done to substantiate the coolability research. Most of the available experimental data is related to the beds packed with single size (mostly spherical) particles, and less data is available for multi-size/irregular-shape particles. There are several analytical models available, which rely on the mean particle diameter and porosity of the bed in their predictions. Two different types of particles were used to investigate coolability of particulate beds at VTT, Finland. The first type is irregular-shape Aluminum Oxide gravel particles whose sizes vary from 0.25 mm to 10 mm, which were employed in the STYX experiment programme (2001-2008). The second type is spherical beads of Zirconium silicate whose sizes vary between 0.8 mm to 1 mm, which were used in the COOLOCE tests (Takasuo et al., 2012) to study the effect of multi-dimensional flooding on coolability. In the present work, the two types of particles are used in the POMECO-FL and POMECO-HT test facility to obtain their effective particle diameters and dryout heat flux of the beds, respectively. The main idea is to check how the heaters' orientations (vertical in COOLOCE vs. horizontal in POMECO-HT) and diameters (6 mm in COOLOCE vs. 3 mm in POMECO-HT) affect the coolability (dryout heat flux) of the test beds. The tests carried out on the POMECO-FL facility using a bed packed with aluminum oxide gravel particles show the effective particle diameter of the gravel particles is 0.65 mm, by which the frictional pressure gradient can be predicted by the Ergun equation. After the water superficial velocity is higher than 0.0025 m/s, the pressure gradient is underestimated. The effective particle diameter of the zirconium particles is found as 0.8 mm. The dryout heat flux is measured on

  1. The effect of open wedge osteotomy on the posterior tibial slope

    OpenAIRE

    Bombaci, Hasan; Canbora, Kerem; Onur, Gokhan; Gorgec, Mucahit

    2004-01-01

    Objectives: Proximal tibial osteotomy improves the alignment and weight distribution of the lower extremity on the coronary plane. However, upper end osteotomy of the tibia may cause changes in the sagittal plane. In this study, we evaluated open wedge osteotomy operations with regard to its effect on the sagittal plane. Methods: The study included 22 knees of 20 female patients (mean age 54.1 years; range 43 to 64 years) who underwent proximal tibial osteotomy for osteoarthritis. Open wed...

  2. Effects of hydrophobic carrier and packing on the mass transfer capabilities in hydrogen-water liquid phase catalytic exchange bed

    International Nuclear Information System (INIS)

    Hydrogen-water liquid phase catalytic exchange bed was packed with 'sandwich' layers of the catalyst and the packing, and the effects of catalyst carrier, inert packing and their filled ratio on the overall mass transfer coefficient (Kya) were investigated experimentally. The results show that C-PTFE is suitable for hydrophobic catalyst. Kya of the bed with catalyst-stainless steel mini-spiral packing is better than that with stainless steel θ-packing, and the active Al2O3 is not suitable for the exchange bed. Moreover, if the stainless steel mini-spiral packing is etched in aqua regia, the operating flexibility and overall mass transfer capability of exchange bed are improved notably. The preferable packing ratio (catalyst/packing) is 1:4. (authors)

  3. Sorting of bed load sediment by flow in meander bends.

    Science.gov (United States)

    Parker, G.; Andrews, E.D.

    1985-01-01

    Equilibrium sorting of coarse mobile bed load sediment in meander bends is considered. A theory of two-dimensional bed load transport of graded material, including the effects of gravity on lateral slopes and secondary currents, is developed. This theory is coupled with a simple tratement of flow in bends, an analytically determined bend shape, and the condition of continuity of each grain size range in transport to describe sorting. The theory indicates that the locus of coarse sediment shifts from the inside bank to the outside bank near the bend apex, as is observed.-Authors

  4. 2-D SIMULATION OF CHANNEL FLOWS WITH MOVEABLE BED

    Institute of Scientific and Technical Information of China (English)

    Wilhelm BECHTELER; Davood FARSHI

    2001-01-01

    This paper presents some preliminary results of 2-D numerical simulation of open channel flow with moveable bed. The unsteady two dimensional channel flow and sediment transport are simulated by solving shallow water equations and sediment continuity equation in conservation form based on unstructured finite volume method. Redefining longitudinal and transverse slopes of the bed is implemented in order to consider them in the bedload equation. A simple modeling treatment dealing with secondary flow effect on sediment movement is also discussed. Finally, two examples of numerical simulation are presented.

  5. Segregation and mixing effects in the riser of a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Mitali Das; Meenakshi Banerjee; R.K. Sah [Indian Institute of Technology, Kharagpur (India). Department of Chemical Engineering

    2007-09-15

    Segregation and mixing effects of binary mixtures of particles having difference in sizes and densities were studied in 0.1016 m-diameter riser of a circulating fluidized bed at gas velocities between 2.01 and 4.681 m/s and solids circulation rate between 12.5 and 50 kg/m{sup 2}s. Two groups of bed materials (three quartz sand-spent fcc catalyst mixtures with different initial mass % of sand and two coal-iron mixtures, one with almost same sizes but with different densities and the other having both different sizes and densities) were used. Using local axial mass % of heavier/coarser particles and their mean sizes the extent of segregation was evaluated. The influence of operating conditions like superficial gas velocity and solids circulation rate on segregation was examined and found that with their increase segregation effects generally tend to decrease and a uniform mixture conforming to initial composition of the mixture results. Using the data available in the literature and those of the present authors an empirical correlation to obtain the extent of segregation in CFBs has been proposed.

  6. A comparison of power analysis methods for evaluating effects of a predictor on slopes in longitudinal designs with missing data.

    Science.gov (United States)

    Wang, Cuiling; Hall, Charles B; Kim, Mimi

    2015-12-01

    In many longitudinal studies, evaluating the effect of a binary or continuous predictor variable on the rate of change of the outcome, i.e. slope, is often of primary interest. Sample size determination of these studies, however, is complicated by the expectation that missing data will occur due to missed visits, early drop out, and staggered entry. Despite the availability of methods for assessing power in longitudinal studies with missing data, the impact on power of the magnitude and distribution of missing data in the study population remain poorly understood. As a result, simple but erroneous alterations of the sample size formulae for complete/balanced data are commonly applied. These 'naive' approaches include the average sum of squares and average number of subjects methods. The goal of this article is to explore in greater detail the effect of missing data on study power and compare the performance of naive sample size methods to a correct maximum likelihood-based method using both mathematical and simulation-based approaches. Two different longitudinal aging studies are used to illustrate the methods. PMID:22357710

  7. Haulage Vehicle Traffic and Runoff Effect on Gully Growth on Roadside Slopes of Unpaved Sand-Quarry Road, Uyo.

    Directory of Open Access Journals (Sweden)

    Obot Ekpo Essien

    2013-10-01

    Full Text Available Rainfall runoff and sand haulage truck traffic count were quantified and regressed on gully soil loss and gully morphometric volume growth on unpaved haulage roadside erosion. The gully erosion on unpaved roadside was accelerated by the agency of runoff in splash wash from the road, and high axle sand haulage trucks traffic. The effect of the Runoff discharge and traffic count, as independent variables and cumulativequantities, on the cumulative soil loss from jagged side slope gullies, and the gully volume growth were very significant at P < 0.01 generally. Predictive coefficient of determination, significant at P < 0.01, were very perfect at R2= 88.8 to 98.9%. Different regimes of association were obtained such as: high runoff and high traffic count; high flow rate and low traffic count, and low runoff and high traffic count for effect and on gully loss and gully volume growth, and they gave accurate and significant relationship. Regulation of sand-mining over a catchment is recommended as it has otherwise destroyed landform and initiated unrestrained gullying.

  8. [Effects of thinning intensities on population regeneration of natural Quercus variabilis forest on the south slope of Qinling Mountains].

    Science.gov (United States)

    Ran, Ran; Zhang, Wen-Hui; He, Jing-Feng; Zhou, Jian-Yun

    2014-03-01

    Taking the natural Quercus variabilis forest in Shangluo, south slope of Qinling Mountains as the object in May 2006 and August 2011, which was under close-to-natural management of different thinning intensities (30%, 20%, 10%), and the un-thinned forest as the control, changes of the stand growth situation before and after thinning, population regeneration, species diversity and soil fertility after 5 years of thinning were analyzed, and the effects of thinning on forestland revegetation and community development were evaluated comprehensively. The results showed that the number of 1-6 years old Q. variabilis seedlings increased with increasing thinning intensity, while no significant difference was found for above 6 years old seedlings. The regeneration potentials of population under 10%, 20% and 30% thinning were respectively increased by 10.8%, 28.5% and 32.9% compared with the control. Thinning promoted the DBH and crown of the trees and shrubs, as well as the height of shrubs, especially for light-loving plants, and the effect of promotion increased with increasing thinning intensity. The species diversity and soil fertility were improved after thinning, in order of 30% > 20% > 10% > control. The thinning intensity of 30% (canopy density 0.6) was more conducive to the continuable development of the natural Q. variabilis forest in which canopy density was above 0.85. PMID:24984485

  9. Muscular activity during uphill cycling: effect of slope, posture, hand grip position and constrained bicycle lateral sways.

    Science.gov (United States)

    Duc, S; Bertucci, W; Pernin, J N; Grappe, F

    2008-02-01

    Despite the wide use of surface electromyography (EMG) to study pedalling movement, there is a paucity of data concerning the muscular activity during uphill cycling, notably in standing posture. The aim of this study was to investigate the muscular activity of eight lower limb muscles and four upper limb muscles across various laboratory pedalling exercises which simulated uphill cycling conditions. Ten trained cyclists rode at 80% of their maximal aerobic power on an inclined motorised treadmill (4%, 7% and 10%) with using two pedalling postures (seated and standing). Two additional rides were made in standing at 4% slope to test the effect of the change of the hand grip position (from brake levers to the drops of the handlebar), and the influence of the lateral sways of the bicycle. For this last goal, the bicycle was fixed on a stationary ergometer to prevent the lean of the bicycle side-to-side. EMG was recorded from M. gluteus maximus (GM), M. vastus medialis (VM), M. rectus femoris (RF), M. biceps femoris (BF), M. semimembranosus (SM), M. gastrocnemius medialis (GAS), M. soleus (SOL), M. tibialis anterior (TA), M. biceps brachii (BB), M. triceps brachii (TB), M. rectus abdominis (RA) and M. erector spinae (ES). Unlike the slope, the change of pedalling posture in uphill cycling had a significant effect on the EMG activity, except for the three muscles crossing the ankle's joint (GAS, SOL and TA). Intensity and duration of GM, VM, RF, BF, BB, TA, RA and ES activity were greater in standing while SM activity showed a slight decrease. In standing, global activity of upper limb was higher when the hand grip position was changed from brake level to the drops, but lower when the lateral sways of the bicycle were constrained. These results seem to be related to (1) the increase of the peak pedal force, (2) the change of the hip and knee joint moments, (3) the need to stabilize pelvic in reference with removing the saddle support, and (4) the shift of the mass

  10. EXPERIMENTAL STUDY ON BED SCOUR IN A 90°CHANNEL BEND

    Institute of Scientific and Technical Information of China (English)

    Masoud GHODSIAN; S. Kamal MOUSAVI

    2006-01-01

    The special feature of bend flow leads to scouring of the bed and bank. Various parameters like flow depth, flow velocity or discharge, geometry of bend and characteristics of bed material may affect the scour process. Experiments were carried out to study the effect of some important parameters on bend scour under clear water condition. Experiments were conducted in a 0.6m wide and 0.7m high flume with 90 degree bend. The lateral variations of bed slope were studied. The maximum depth of scour was correlated to densimetric Froude number, relative bend radius and relative depth of flow.

  11. Effectiveness of a Reduced-Risk Insecticide Based Bed Bug Management Program in Low-Income Housing

    Directory of Open Access Journals (Sweden)

    Narinderpal Singh

    2013-11-01

    Full Text Available Bed bug (Cimex lectularius L. infestations are becoming increasingly common in low-income communities. Once they are introduced, elimination is very difficult. As part of the efforts to develop effective and safe bed bug management programs, we conducted a laboratory study evaluating the efficacy of a reduced-risk insecticide—Alpine aerosol (0.5% dinotefuran. We then conducted a field evaluation of a reduced-risk insecticide based integrated pest management (IPM program in low-income family apartments with young children. In laboratory evaluations, direct spray and 5 min exposure to dry Alpine aerosol residue caused 100.0 ± 0.0 and 91.7 ± 8.3% mortality to bed bug nymphs, respectively. Direct Alpine aerosol spray killed 91.3 ± 4.3% of the eggs. The IPM program included education, steam, bagging infested linens, placing intercepting devices under furniture legs and corners of rooms, applying Alpine aerosol and Alpine dust (0.25% dinotefuran, 95% diatomaceous earth dust, and regularly scheduled monitoring and re-treatment. Nine apartments ranging from 1–1,428 (median: 29 bed bugs based on visual inspection and Climbup interceptor counts were included. Over a 6-month period, an average 172 g insecticide (Alpine aerosol + Alpine dust was used in each apartment, a 96% reduction in pesticide usage compared to chemical only treatment reported in a similar environment. The IPM program resulted in an average of 96.8 ± 2.2% reduction in the number of bed bugs. However, elimination of bed bugs was only achieved in three lightly infested apartments (<30 bed bugs at the beginning. Elimination success was closely correlated with the level of bed bug populations.

  12. Effectiveness of a Batteryless and Wireless Wearable Sensor System for Identifying Bed and Chair Exits in Healthy Older People.

    Science.gov (United States)

    Shinmoto Torres, Roberto Luis; Visvanathan, Renuka; Hoskins, Stephen; van den Hengel, Anton; Ranasinghe, Damith C

    2016-01-01

    Aging populations are increasing worldwide and strategies to minimize the impact of falls on older people need to be examined. Falls in hospitals are common and current hospital technological implementations use localized sensors on beds and chairs to alert caregivers of unsupervised patient ambulations; however, such systems have high false alarm rates. We investigate the recognition of bed and chair exits in real-time using a wireless wearable sensor worn by healthy older volunteers. Fourteen healthy older participants joined in supervised trials. They wore a batteryless, lightweight and wireless sensor over their attire and performed a set of broadly scripted activities. We developed a movement monitoring approach for the recognition of bed and chair exits based on a machine learning activity predictor. We investigated the effectiveness of our approach in generating bed and chair exit alerts in two possible clinical deployments (Room 1 and Room 2). The system obtained recall results above 93% (Room 2) and 94% (Room 1) for bed and chair exits, respectively. Precision was >78% and 67%, respectively, while F-score was >84% and 77% for bed and chair exits, respectively. This system has potential for real-time monitoring but further research in the final target population of older people is necessary. PMID:27092506

  13. Effects of Daily Centrifugation on Segmental Fluid Distribution in Bed-rested Subjects

    Science.gov (United States)

    Diedrich, Andre; Moore, S. T.; Stenger, M.; Arya, T. M.; Newby, N.; Tucker, J. M.; Milstead, L.; Acock, K.; Knapp, C.; Jevans, J.; Paloski, W.

    2007-01-01

    The effect of daily centrifugation on segmental fluid distribution have been studied during 21 days of 6 degree head down bedrest. One group (N=7) underwent no countermeasure while the other (N=8) received a daily, one hour, dose (2.5 gz at the foot, decreasing to 1.0 gz at the heart) of artificial gravity (AG) training on the Johnson Space Center short radius centrifuge. Fluid shifts of thoracic(VTO), abdominal (VAB), thigh (VTH), and calf (VCA) regions were measured by the tetrapolar segmental body impedance technique. Untrained subjects reduced their total volume from 18.9 plus or minus 0.5L to 17.9 plus or minus 0.9L (MN plus or minus SE, P less than 0.05) while trained subjects maintained their total volume. In untrained, control, subjects after bed rest, there was a trend toward reduced volume in all segments, with significant reductions in thigh and calf (fig, P less than 0.05). Trained subjects maintained volume in all segments. Our data indicate that artificial gravity treatment counteracts bed rest-induced hypovolemia.

  14. Effectiveness of Comprehensive Nursing Care Relieving Problems of Hospitalized High-Risk Pregnant Women in Bed Rest

    Directory of Open Access Journals (Sweden)

    Umran Yesiltepe Oskay

    2012-04-01

    Full Text Available It is well known that bed rest at home or in hospital has many physical and psychosocial effects on pregnant women. Objective: This study is type of an intervention study which has been conducted to determine bed rest related physical and psychosocial problems of hospitalized high-risk pregnant women and effectiveness of a comprehensive nursing care plan in solving to those problems. Material and Method: The sample group was selected among high-risk pregnant women who were hospitalized in perinatology wards of three hospitals in Istanbul between June 2000 and June 2001. The sample consisted of 60 high-risk pregnant women (30 Intervention group, 30 control group who have completed 20th gestational weeks and have had partial or complete bed rest in hospital for at least 10 day and did not have a systemic disease or fetal abnormality and were willing to participate in the study. Data collection was made by Patient Assessment Form, Antepartum Symptom Checklist and Antepartum Hospital Stressors Inventory. Control group were not implemented any intervention except for routine ward care. Intervention group with complete or partial bed rest were given comprehensive nursing care in order to ensure deal with problems that arise during the bed rest. All participants filled out “Antepartum Symptom Checklist” and “Antepartum Hospital Stressors Inventory” in the end of bed rest. And body weight was followed in the beginning and end of the study. Data defining the number, percentage, mean, median and standard deviation values were used. The relative risk used in the evaluation of the risk. Analysis of the data, chi-square and Fisher's exact test for discrete variables, the Mann-Whitney U test was used for continuous variables. Results: The control and Intervention groups were similar in manner of demographic and obstetric characteristics, high-risk status, type and duration of bed rest (p>0.05. It was found that Intervention group which was provided a

  15. Effects of circulating fluidized bed combustion (CFBC) fly ashes as filler on the performances of asphalt

    Energy Technology Data Exchange (ETDEWEB)

    Qin Li; Hui Xu; Xiaoru Fu; Chen Chen; Jianping Zhai [Nanjing University, Nanjing (China). State Key Laboratory of Pollution Control and Resource Reuse

    2009-03-15

    This work investigated the potential of utilizing circulating fluidized bed combustion (CFBC) fly ashes (CFAs) as alternative filler, substituting mineral powders (MPs) that are widely used in asphalt concrete. Physico-chemical characteristics of the CFAs and MPs, as well as effects of different mix designs of CFAs and asphalt on asphalt performances were examined, including moisture susceptibility, viscosity, ductility, softening point, penetration, and antiaging performances. The results of the study show that generally the CFAs have greater effects than the MPs on improving the performances of asphalt, and that the specific surface area (SSA), free CaO (f-CaO), morphology, and mineralogical phases of the CFAs are more favorable than those of the MPs respectively, while the alkaline values, hydrophilic coefficients, particle size distributions (PSDs), and water contents of the two fillers are similar. It is suggested that CFAs may be more suitable than MPs for the use as asphalt concrete filler.

  16. THE EFFECT OF REINFORCEMENT ON THE GBFS AND LIME TREATED MARINE CLAY FOR FOUNDATION SOIL BEDS

    Directory of Open Access Journals (Sweden)

    D. Koteswara Rao,

    2011-03-01

    Full Text Available India being peninsular country has large area coming under coastal region and also it has been the habitat for considerable percentage of population. The marine clays are generally found in the coastal region of West Bengal, Orissa, Andhra Pradesh, Tamilnadu, Kerala, Karnataka, Maharashtra and some parts of Gujarat. Marine or soft clays exists in these region are weak and deformative in nature. The present study deals with the strength characteristics of the marine clay collected from Kakinada Sea Port Ltd, Kakinada, A.P, India. The effect of lime on the strength characteristics of marine clay are studied in this investigation along with the reinforcement effect using geotextile as reinforcement and separator for the foundation soil bed.

  17. Mesoscale Characterization of Coupled Hydromechanical Behavior of a Fractured Porous Slope in Response to Free Water-Surface Movement

    Energy Technology Data Exchange (ETDEWEB)

    Rutqvist, Jonny; Guglielmi, Y.; Cappa, F.; Rutqvist, J.; Tsang, C.-F.; Thoraval, A.

    2008-05-15

    To better understand the role of groundwater-level changes on rock-slope deformation and damage, a carbonate rock slope (30 m x 30 m x 15 m) was extensively instrumented for mesoscale hydraulic and mechanical measurements during water-level changes. The slope is naturally drained by a spring that can be artificially closed or opened by a water gate. In this study, a 2-hour slope-dewatering experiment was analyzed. Changes in fluid pressure and deformation were simultaneously monitored, both at discontinuities and in the intact rock, using short-base extensometers and pressure gauges as well as tiltmeters fixed at the slope surface. Field data were analyzed with different coupled hydromechanical (HM) codes (ROCMAS, FLAC{sup 3D}, and UDEC). Field data indicate that in the faults, a 40 kPa pressure fall occurs in 2 minutes and induces a 0.5 to 31 x 10{sup -6} m normal closure. Pressure fall is slower in the bedding-planes, lasting 120 minutes with no normal deformation. No pressure change or deformation is observed in the intact rock. The slope surface displays a complex tilt towards the interior of the slope, with magnitudes ranging from 0.6 to 15 x 10{sup -6} rad. Close agreement with model for both slope surface and internal measurements is obtained when a high variability in slope-element properties is introduced into the models, with normal stiffnesses of k{sub n{_}faults} = 10{sup -3} x k{sub n{_}bedding-planes} and permeabilities of k{sub h{_}faults} = 10{sup 3} x k{sub h{_}bedding-planes}. A nonlinear correlation between hydraulic and mechanical discontinuity properties is proposed and related to discontinuity damage. A parametric study shows that 90% of slope deformation depends on HM effects in a few highly permeable and highly deformable discontinuities located in the basal, saturated part of the slope while the remaining 10% are related to elasto-plastic deformations in the low-permeability discontinuities induced by complex stress/strain transfers from

  18. COUPLING EFFECT BETWEEN RELIABILITY OF BEDDING LAYER AND STABILITY OF DOWNSTREAM CONCRETE SLAB OF OVERFLOW EARTH-ROCK COFFERDAM

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The protection of downstream concrete slab is a key issue for the stability of overflow earth-rock cofferdam. The coupling effect between bedding layer and concrete slab was taken into account when the stability of downstream concrete slab was researched. The characteristics of overflow and seepage over the downstream concrete slab were investigated when floodwater passes over the cofferdam. Firstly a limit equation of seepage failure for the bedding layer was derived with the consideration of geometric and mechanical factors, and a reliability model was established and numerically simulated. Then based on the reliability calculation for the bedding layer, the coupling effect between bedding layer and downstream concrete slab was analyzed. Under the most unfavorable pressure condition for the concrete slab, its instability criterion was put forward, which offers a structural design tool of downstream concrete slab for overflow earth-rock cofferdam. Compared with model tests, it shows that the model of reliability calculation of bedding layer and the stability analysis of downstream concrete slab are effective.

  19. Effect of 14 days of bed rest on urine metabolite excretion and plasma enzyme levels

    Science.gov (United States)

    Pace, N.; Grunbaum, B. W.; Kodama, A. M.; Rahlmann, D. F.; Newsom, B. D.

    1974-01-01

    After 1 week of ambulatory base-line measurement, a group of 8 men 19-26 years of age remained continuously recumbent for 14 days. Studies were continued for 1 week following the prolonged recumbency. Urine excretion rates for a number of constituents were determined 2 days before bed rest, on day 14 of bed rest, and day 6 after bed rest. Blood plasma samples were also obtained at these times, and analyzed for several enzymes. On day 14 of bed rest significant increases were observed in urine excretion of total osmotically-active substances, magnesium, calcium, phosphate, creatinine, hydroxyproline, and 17-OH corticosteroids. A decrease occurred in urinary glucose excretion. Plasma levels of alkaline phosphatase and LDH-3 were depressed, while plasma GPT was elevated. Many of these changes persisted on day 6 after bed rest, and are interpreted as concomitants of the disuse atrophy of the musculoskeletal system that characterizes prolonged bed rest and weightlessness.

  20. Effect of substrate morphology slope distributions on light scattering, nc-Si:H film growth, and solar cell performance.

    Science.gov (United States)

    Kim, Do Yun; Santbergen, Rudi; Jäger, Klaus; Sever, Martin; Krč, Janez; Topič, Marko; Hänni, Simon; Zhang, Chao; Heidt, Anna; Meier, Matthias; van Swaaij, René A C M M; Zeman, Miro

    2014-12-24

    Thin-film silicon solar cells are often deposited on textured ZnO substrates. The solar-cell performance is strongly correlated to the substrate morphology, as this morphology determines light scattering, defective-region formation, and crystalline growth of hydrogenated nanocrystalline silicon (nc-Si:H). Our objective is to gain deeper insight in these correlations using the slope distribution, rms roughness (σ(rms)) and correlation length (lc) of textured substrates. A wide range of surface morphologies was obtained by Ar plasma treatment and wet etching of textured and flat-as-deposited ZnO substrates. The σ(rms), lc and slope distribution were deduced from AFM scans. Especially, the slope distribution of substrates was represented in an efficient way that light scattering and film growth direction can be more directly estimated at the same time. We observed that besides a high σ(rms), a high slope angle is beneficial to obtain high haze and scattering of light at larger angles, resulting in higher short-circuit current density of nc-Si:H solar cells. However, a high slope angle can also promote the creation of defective regions in nc-Si:H films grown on the substrate. It is also found that the crystalline fraction of nc-Si:H solar cells has a stronger correlation with the slope distributions than with σ(rms) of substrates. In this study, we successfully correlate all these observations with the solar-cell performance by using the slope distribution of substrates. PMID:25418361

  1. NONUNIFORM OPEN CHANNEL FLOW WITH UPWARD SEEPAGE THROUGH LOOSE BEDS

    Institute of Scientific and Technical Information of China (English)

    Subhasish DEY

    2003-01-01

    The Reynolds stress and bed shear stress are important parameters in fluvial hydraulics. Steadynonuniform flow in open channels with streamwise sloping beds having upward seepage through loose beds is theoretically analyzed to estimate the Reynolds stress and bed shear stress. Equations of the Reynolds stress and bed shear stress are developed, assuming a modified logarithmic velocity distribution law due to upward seepage, and using the Reynolds and continuity equations of twodimensional flow in open channels.

  2. The effective thermal conductivity in packed beds of spheres especially in the core of a high temperature reactor

    International Nuclear Information System (INIS)

    Cell and quasihomogeneous models for determining of the effective thermal conductivity in packed beds are compared and their evidence is investigated by own experimental data both in the high and low temperature range under consideration of the stationary fluid. The quasihomogeneous model is extended to packed beds with spheres of relatively low thermal conductivity. The void radiation heat transfer is considered theoretically and is determined experimentally. Simplified formulas are presented for the computation of the effective thermal conductivity on the core of a high temperature reactor within a temperature range of 25000C. (orig.)

  3. Fundamental Limits on the Subthreshold Slope in Schottky Source/Drain Black Phosphorus Field-Effect Transistors.

    Science.gov (United States)

    Haratipour, Nazila; Namgung, Seon; Oh, Sang-Hyun; Koester, Steven J

    2016-03-22

    The effect of thickness, temperature, and source-drain bias voltage, V(DS), on the subthreshold slope, SS, and off-state properties of black phosphorus (BP) field-effect transistors is reported. Locally back-gated p-MOSFETs with thin HfO2 gate dielectrics were analyzed using exfoliated BP layers ranging in thickness from ∼4 to 14 nm. SS was found to degrade with increasing V(DS) and to a greater extent in thicker flakes. In one of the thinnest devices, SS values as low as 126 mV/decade were achieved at V(DS) = -0.1 V, and the devices displayed record performance at V(DS) = -1.0 V with SS = 161 mV/decade and on-to-off current ratio of 2.84 × 10(3) within a 1 V gate bias window. A one-dimensional transport model has been utilized to extract the band gap, interface state density, and the work function of the metal contacts. The model shows that SS degradation in BP MOSFETs occurs due to the ambipolar turn on of the carriers injected at the drain before the onset of purely thermionic-limited transport at the source. The model is further utilized to provide design guidelines for achieving ideal SS and meet off-state leakage targets, and it is found that band edge work functions and thin flakes are required for ideal operation at high V(DS). This work represents a comprehensive analysis of the fundamental performance limitations of Schottky-contacted BP MOSFETs under realistic operating conditions. PMID:26914179

  4. The slope effect of a capacitive resonator profile fabricated by a DRIE process on the performance of an MEMS disk resonator

    International Nuclear Information System (INIS)

    The thickness of a capacitive disk resonator can be increased by selecting a deep reactive ion etching (DRIE) process for reducing motional resistance. However, the DRIE process sometimes causes MEMS capacitive resonators to have a non-ideal profile. In this paper, the slope effect of a resonator profile fabricated by a DRIE process on the capacitance, electrostatic force, electrical stiffness, motional resistance and output current of the capacitive resonator is analyzed. The relation curves between these parameters and the sloped angle are obtained theoretically. The results show that the capacitance, electrostatic force, electrical stiffness and output current decrease as the sloped angle increases, but the motional resistance obviously increases. By capturing the electric field distribution of a capacitive resonator with different ratios of the gap to thickness by using FEM software ANSYS, the effects of slope angle and thickness on the natural frequency of the resonator are investigated. The analyzed results can provide the theoretical basis for designing high-performance MEMS disk resonators fabricated by the DRIE process. (paper)

  5. THE 05.06.2012 SLOPE FLOOD RUNOFF IN THE LOWER BASIN OF ILIŞUA RIVER – CAUSES, EFFECTS AND FUTURE MEASURES

    Directory of Open Access Journals (Sweden)

    Gh. Şerban

    2013-03-01

    Full Text Available In the context of the Code Yellow for rainfalls and storms, issued by National Administration of Meteorology (NAM, a downpoor occurred on the 5th of June 2012 in the afternoon, between 16.00 and 16.30 hours, with maximum intensity in the area of the Dobric – Dobricel – Spermezeu – Păltineasa – Dumbrăviţa – Căianu Mare – Căianu Mic localities. The extreme meteorological event has caused a severe slope runoff. Fortunately, the effects did not include any victims, although they were very severe, judging by the blocking of tens of kilometres of road, the flooding of almost 200 households and several hundreds of hectares of agricultural land. The risk map showing the occurrence distribution of slope flood runoff and associate meteorological events reveals the need of implementing strict measures consisting in: partial afforestation of the two thirds of the cleared slopes, management and diversion of floods that discharge their liquid and alluvial material over the human settlements located in the closest proximity of the slopes, resizing of the access infrastructure (bridges, footbridges and flood defence infrastructure (dams, runoff drainage system, scenario-based training of population to react promptly to the development of the extreme hydrometeorological events. On the contrary, the questionnaires applied in the study area reveal a lower preparedness level of the population for an efficient, optimum reaction, in order to significantly reduce the effects of these phenomena.

  6. Effects of 45-day -6° head-down bed rest on the time-based prospective memory

    Science.gov (United States)

    Chen, SiYi; Zhou, RenLai; Xiu, LiChao; Chen, ShanGuang; Chen, XiaoPing; Tan, Cheng

    2013-03-01

    The research explored the effects of 45-day -6° head-down bed rest (HDBR) simulation of microgravity on the time-based prospective memory (PM) with 16 males. The time-based prospective memory task was performed on the 2nd day before HDBR, on the 11th, 20th, 32nd, and 40th days during HDBR, and on the 8th day after HDBR, and subjects' anxiety and depression feelings were recorded simultaneously using Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI). The results demonstrated that it showed decreased accuracy of PM responses and frequency of clock checks during and after bed rest; long term bed rest did not induce significant emotional changes. The deficit of prospective memory performance induced by long term HDBR may result from a lack of aerobic physical activity or changes in the prefrontal cortex, but it remains to be determined.

  7. The effect of slope exposition on the growth dynamics of Larix gmelinii in permafrost conditions of Central Siberia. I. Differences in tree radial dynamics growth in the north- and south-facing slopes

    Directory of Open Access Journals (Sweden)

    А. V. Benkova

    2015-08-01

    Full Text Available This paper is devoted to revealing the distinctive characteristics of radial growth of larch trees (Larix gmelinii (Rupr. Rupr. growing in permafrost contrast conditions of the north and south facing slopes (Central Siberia, 64°19´23˝ N, 100°13´28˝ E. Even-aged larch stems regenerated after strong fire in 1899 in opposite north and south facing slopes of the hills situated on the banks of Kulingdakan stream were under study. Two sample sites at the middle part of the slopes were established. 23 model trees in the north facing slope and 13 ones in the south-facing slope were selected for dendrochronological analysis. From each tree, disks at 1.3 m height of the stems were taken. Tree ring widths were measured, comparative analysis of dynamics of radial growth in the slopes was made. In order to separate time intervals, characterized by distinctive climate impact on radial increment, sliding response functions were calculated and analyzed. Daily solar radiation for both sample sites was calculated. The results showed that solar radiation in the north-facing slope is 20 % less than that in south-facing slope. Solar radiation regime promotes intensive thickening of moss-lichen cover, so that its thickness to 2009 was nearly two times thicker than in south-facing slope. Both factors affected the worth thermal soil growth conditions in the north facing slope. The latter was responsible for narrower ring widths formation in the stems and governed higher sensitivity of the trees to air temperature in the periods of cambium reactivation, start and intensive growth.

  8. Effect of grade-control structures at various stages of their destruction on bed sediments and local channel parameters

    Science.gov (United States)

    Galia, Tomáš; Škarpich, Václav; Hradecký, Jan; Přibyla, Zdeněk

    2016-01-01

    Grade-control structures (GCSs) represent the typical management of torrential streams, preventing massive bed erosion and bedload transport. The original and present geometric and sedimentary parameters of 18 GCSs at various stages of their destruction since the 1970s were evaluated to determine the relationship between the former and present-day components of the managed Mohelnice River (the western Carpathians, Czech Republic). The latest changes in the GCS geometry, related scour holes, and bed surface grain size of sedimentary wedges were caused by the 2010 flood event of 20-50 R.I. discharge. No relationship exists between the bed surface grain sizes and the present water drop or the present equilibrium channel slope of the sedimentary wedge. A significant downstream coarsening of the largest grain size percentile represented by D95 is detected through the sequence of GCSs. Also, statistically insignificant trends in downstream coarsening were observed for D16, D50, and D84 grain sizes. However, the investigated sequence is still passable for grain diameters up to 200 mm during high-magnitude floods similar to the 2010 event, as documented by the development of a confluent gravel bar downstream of the sequence. Bedload transport simulations provide the highest bedload transport rates for the initial stage of the uppermost studied channel reach without the presence of GCSs (30,000 kg min- 1 for Q50). Grade-control structures reconstruction in the 1970s significantly decreased transport rates (> 2000 kg min- 1 for Q50). Owing to the erosion of GCS crests and an increase in related equilibrium channel slope, damage on GCSs can lead to an increase in bedload transport intensity (13,000 kg min- 1 for Q50). Significant linear relationships exist among the present parameters of the scour holes (length of scour hole, maximum scour depth, and horizontal distance between the point of maximum depth and the GCS crest). A statistical significant power relationship exists

  9. Effect of Air Staging and Limestone Addition on Emissions of SO2 and NOx in Circulating Fluidized Bed Combustion

    International Nuclear Information System (INIS)

    The object of this work is to provide more detailed knowledge about the effect of air staging and its relation to the addition of limestone on the emissions of SO2 and NOx from fluidized bed combustors. This knowledge can be used in models of (circulating) fluidized bed combustors for the development of control strategies. The effect of air staging can be divided in to two parts: (1) The effect on the hydrodynamics in a circulating fluidized bed; and (2) The effect on the local gas concentrations, especially the O2 concentration. In this work the influence of both these effects on the SO2 and NOx emissions from (circulating) fluidized bed combustors with air staging was investigated. In Chapter 2 the influence air staging and the use of secondary air injection on the hydrodynamics in a circulating fluidized beds is described. In the first section of that chapter a literature review is given. In the second section an experimental study is presented on the solids distribution and circulation rate under different air staging conditions. Chapter 3 presents fixed bed studies on the SO2 retention by limestone. To understand the influence of air staging, the effect of oxygen on the SO2 retention was investigated. The kinetics were determined and the so-called grain model was used to model the SO2 retention. In Chapter 4 an extensive study was made on the kinetics of the formation of NO from NH3 and the influence of oxygen on these reactions. The kinetics and the activation energies of both homogenous reactions and reactions catalyzed by limestone were determined and the effect of oxygen was investigated. Chapter 5 presents an experimental study and modeling work on the effect of water and CO2 on the reactivity of limestone. It was found that the presence of water reduced the reactivity of limestone significantly. In Chapter 6 the oxidation of NH3 over partially sulphated limestone is studied. A model is developed that describes the NO formation and selectivity as a

  10. High short-term effectiveness of modulated dry bed training in adolescents and young adults with treatment-resistant enuresis

    NARCIS (Netherlands)

    Hofmeester, I.; Cobussen-Boekhorst, J.G.L.; Kortmann, B.B.M.; Mulder, Z.; Steffens, M.G.; Feitz, W.F.J.; Van Capelle, J.W.; Blanker, M.H.

    2015-01-01

    INTRODUCTION & OBJECTIVES: Two percent of adolescents and young adults suffer from therapy-resistant enuresis, with considerable negative impact on self-esteem and relationships. We evaluated the effect of a Modulated Dry Bed Training (MDBT) in a previously therapyresistant group of adolescents with

  11. Coupling of soil solarization and reduced rate fumigation: Effects on methyl iodide emissions from raised beds under field conditions

    Science.gov (United States)

    Using field plots, we studied the effect on methyl iodide (MeI) emissions of coupling soil solarization (passive and active) and reduced rate fumigation (70% of a standard fumigation) in raised beds under virtually impermeable film (VIF). The results showed that for the standard fumigation and the p...

  12. Evaluation of Surface Slope Effects on Ripple Orientations Observed on Sand Dunes in the Terra Tyrrhena Region of Mars

    Science.gov (United States)

    Zimbelman, J. R.; Johnson, M. B.

    2014-12-01

    The High Resolution Imaging Science Experiment (HiRISE) has revealed abundant wind ripples on sand dunes across Mars. Ripple orientations have been documented using HiRISE images of sand dunes at 24 widely distributed sites across Mars, in order to identify the last significant wind directions at these locations. Howard (GSAB, 1977) gives a mathematical expression for how surface slopes on a sand dune can affect the orientation of ripples with respect to the formative winds. In order to evaluate this mechanism for measured ripple orientations on Mars, quantitative data for surface slopes on the sand dunes is required. Stereo pairs of HiRISE images are used to generate Digital Terrain Models (DTMs) with postings of one meter. In June 2014 we produced a DTM of sand dunes in the Terra Tyrrhena region of Mars (14.55° S, 97.77° E) using SOCET SET at the Astrogeology Branch, USGS-Flagstaff. Typically it is difficult for feature matching software to work well on sand dunes, but our stereo images (ESP_022609_1655 and ESP_026675_1655) were obtained only six Earth days apart under excellent illumination conditions. The Terra Tyrrhena DTM had remarkably few artifacts on the sand dunes (except at slip faces, where the average slope between slip face crest and base was interpolated) and excellent control from irregular terrain exposed in interdune areas. Slopes on the stoss sides of sand dunes are generally ripple deflection angles should be ripple orientations to account for surface slopes utilizing the DTM data, and so far we do not see major changes to inferred surface wind directions that would be derived directly from the ripple orientations.

  13. Effects of prolonged head-down bed rest on physiological responses to moderate hypoxia

    Science.gov (United States)

    Loeppky, J. A.; Roach, R. C.; Selland, M. A.; Scotto, P.; Greene, E. R.; Luft, U. C.

    1993-01-01

    To determine the effects of hypoxia on physiological responses to simulated zero-gravity cardiopulmonary and fluid balance measurements were made in 6 subjects before and during 5-degree head-down bed rest (HDBR) over 8 d at 10,678 ft and a second time at this altitude as controls (CON). The V-dot(O2)(max) increased by 9 percent after CON, but fell 3 percent after HDBR. This reduction in work capacity during HDBR could be accounted for by inactivity. The heart rate response to a head-up tilt was greatly enhanced following HDBR, while mean blood pressure was lower. No significant negative impact of HDBR was noted on the ability to acclimatize to hypoxia in terms of pulmonary mechanics, gas exchange, circulatory or mental function measurements. No evidence of pulmonary interstitial edema or congestion was noted during HDBR at the lower PIO2 and blood rheology properties were not negatively altered. Symptoms of altitude illness were more prevalent, but not marked, during HDBR and arterial blood gases and oxygenation were not seriously effected by simulated microgravity. Declines in base excess with altitude were similar in both conditions. The study demonstrated a minimal effect of HDBR on the ability to adjust to this level of hypoxia.

  14. Effects of cohesion on the flow patterns of granular materials in spouted beds

    Science.gov (United States)

    Zhu, Runru; Li, Shuiqing; Yao, Qiang

    2013-02-01

    Two-dimensional spouted bed, capable to provide both dilute granular gas and dense granular solid flow patterns in one system, was selected as a prototypical system for studying granular materials. Effects of liquid cohesion on such kind of complex granular patterns were studied using particle image velocimetry. It is seen that the addition of liquid oils by a small fraction of 10-3-10-2 causes a remarkable narrowing (about 15%) of the spout area. In the dense annulus, as the liquid fraction increases, the downward particle velocity gradually decreases and approaches a minimum where, at a microscopic grain scale, the liquid bridge reaches spherical regimes with a maximum capillarity. Viscous lubrication effect is observed at a much higher fraction but is really weak with respect to the capillary effect. In the dilute spout, in contrast to the dry grains, the wet grains have a lightly smaller acceleration in the initial 1/3 of the spout, but have a dramatically higher acceleration in the rest of the spout. We attribute the former to the additional work needed to overcome interparticle cohesion during particle entrainment at the spout-annulus interface. Then, using mass and momentum balances, the latter is explained by the relative higher drag force resulting from both higher gas velocities and higher voidages due to spout narrowing in the wet system. The experimental findings will provide useful data for the validation of discrete element simulation of cohesive granular-fluid flows.

  15. Branched-chain amino acid supplementation during bed rest: effect on recovery

    Science.gov (United States)

    Stein, T. P.; Donaldson, M. R.; Leskiw, M. J.; Schluter, M. D.; Baggett, D. W.; Boden, G.

    2003-01-01

    Bed rest is associated with a loss of protein from the weight-bearing muscle. The objectives of this study are to determine whether increasing dietary branched-chain amino acids (BCAAs) during bed rest improves the anabolic response after bed rest. The study consisted of a 1-day ambulatory period, 14 days of bed rest, and a 4-day recovery period. During bed rest, dietary intake was supplemented with either 30 mmol/day each of glycine, serine, and alanine (group 1) or with 30 mmol/day each of the three BCAAs (group 2). Whole body protein synthesis was determined with U-(15)N-labeled amino acids, muscle, and selected plasma protein synthesis with l-[(2)H(5)]phenylalanine. Total glucose production and gluconeogenesis from alanine were determined with l-[U-(13)C(3)]alanine and [6,6-(2)H(2)]glucose. During bed rest, nitrogen (N) retention was greater with BCAA feeding (56 +/- 6 vs. 26 +/- 12 mg N. kg(-1). day(-1), P supplementation on either whole body, muscle, or plasma protein synthesis or the rate of 3-MeH excretion. Muscle tissue free amino acid concentrations were increased during bed rest with BCAA (0.214 +/- 0.066 vs. 0.088 +/- 0.12 nmol/mg protein, P glucose production and gluconeogenesis from alanine were unchanged with bed rest but were significantly reduced (P < 0.05) with the BCAA group in the recovery phase. In conclusion, the improved N retention during bed rest is due, at least in part, to accretion of amino acids in the tissue free amino acid pools. The amount accreted is not enough to impact protein kinetics in the recovery phase but does improve N retention by providing additional essential amino acids in the early recovery phase.

  16. Effects of Artificial Gravity and Bed Rest on Spatial Orientation and Balance Control

    Science.gov (United States)

    Paloski, William H.; Moore, S. T.; Feiveson, A. H.; Taylor, L. C.

    2007-01-01

    While the vestibular system should be well-adapted to bed rest (a condition it experiences approximately 8/24 hrs each day), questions remain regarding the degree to which repeated exposures to the unusual gravito-inertial force environment of a short-radius centrifuge might affect central processing of vestibular information used in spatial orientation and balance control. Should these functions be impaired by intermittent AG, its feasibility as a counter-measure would be diminished. We, therefore, examined the effects of AG on spatial orientation and balance control in 15 male volunteers before and after 21 days of 6 HDT bed rest (BR). Eight of the subjects were treated with daily 1hr AG exposures (2.5g at the feet; 1.0g at the heart) aboard a short radius (3m) centrifuge, while the other seven served as controls (C). Spatial orientation was assessed by measures of ocular counter-rolling (OCR; rotation of the eye about the line of sight, an otolith-mediated reflex) and subjective visual vertical (SVV; perception of the spatial upright). Both OCR and SVV measurements were made with the subject upright, lying on their left sides, and lying on their right sides. OCR was measured from binocular eye orientation recordings made while the subjects fixated for 10s on a point target directly in front of the face at a distance of 1 m. SVV was assessed by asking subjects (in the dark) to adjust to upright (using a handheld controller) the orientation of a luminous bar randomly perturbed (15) to either side of the vertical meridian. Balance control performance was assessed using a computerized dynamic posturography (CDP) protocol similar to that currently required for all returning crew members. During each session, the subjects completed a combination of trials of sensory organization test (SOT) 2 (eyes closed, fixed platform) and SOT 5 (eyes closed, sway-referenced platform) with and without static and dynamic pitch plane head movements (plus or minus 20 deg., dynamic

  17. Influence of Ordovician carbonate reservoir beds in Tarim Basin by faulting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The quality of the Ordovician carbonate reservoir beds in the Tarim Basin is closely related to the development of secondary pores,fractures and cavities. Karstification is important in improving the properties of reservoir beds,and karstification related to unconformity has caught wide attention. Compared with the recent research on the unconformity karst reservoir bed improvement,this paper shows a new way of carbonate reservoir bed transformation. Based on field survey,core and slices observation,transformation of Ordovician carbonate reservoir beds by faulting can be classified into three types: (1) Secondary faults and fracturs generated by faulting improved carbonate reservoir bed properties,which were named the Lunnan or Tazhong82 model; (2) upflow of deep geothermal fluids caused by faulting,with some components metasomatizing with carbonate and forming some secon-dary deposit,such as fluorite. It can improve carbonate reservoir bed properties obviously and is named the Tazhong 82 model; and (3) the faulting extending up to the surface increased the depth of supergene karstification and the thickness of reservoir bed. It is named the Hetianhe model. Trans-formation effect of carbonate reservoir beds by faulting was very significant,mainly distributed on the slopes or on the edge or plunging end of the uplift.

  18. Radioactive tracer study of the effect of swells on the sea bed

    International Nuclear Information System (INIS)

    Little is known at present about the limits of the effect of swells on the sea bed and the subject is a controversial one in scientific circles connected with maritime hydraulics. A programme of general studies using radioisotope-labelled sediments has therefore been put in hand to determine the extent of this action and to find a definitive semi-empirical formulation of the relations Qsub(s)=f(H,S,p), i.e. the solid flow-rate Qsub(s) as a function of hydraulic conditions H (especially the swell characteristics), sediment conditions S and depth p. This programme has consisted in carrying out several series of immersions of labelled sediments perpendicular to a carefully selected coastline, at a number of depths down to 25m. A study of this nature was done one year in a region subject to tides (in the Atlantic near Bayonne) and one year in a nontidal region (the Mediterranean near Sete). A number of transport characteristics were found, for example the limits of the effect in particle size terms, cumulative transport as a function of energy balances in the swell and the existence of a critical depth below which solid transport becomes negligible (in hydraulic, not geological, terms). These parameters are discussed quantitatively and the repercussions they may have on problems of coastal civil engineering projects - especially the creation of artificial beaches by the use of solid matter deposited off shore - are evaluated. (author)

  19. Effect of Operating Conditions on Catalytic Gasification of Bamboo in a Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Thanasit Wongsiriamnuay

    2013-01-01

    Full Text Available Catalytic gasification of bamboo in a laboratory-scale, fluidized bed reactor was investigated. Experiments were performed to determine the effects of reactor temperature (400, 500, and 600°C, gasifying medium (air and air/steam, and catalyst to biomass ratio (0 : 1, 1 : 1, and 1.5 : 1 on product gas composition, H2/CO ratio, carbon conversion efficiency, heating value, and tar conversion. From the results obtained, it was shown that at 400°C with air/steam gasification, maximum hydrogen content of 16.5% v/v, carbon conversion efficiency of 98.5%, and tar conversion of 80% were obtained. The presence of catalyst was found to promote the tar reforming reaction and resulted in improvement of heating value, carbon conversion efficiency, and gas yield due to increases in H2, CO, and CH4. The presence of steam and dolomite had an effect on the increasing of tar conversion.

  20. Slow pyrolysis of different PVC types in a bubbling fluidized bed. Stabilizer effects

    Energy Technology Data Exchange (ETDEWEB)

    Saeed, Loay; Tohka, Antti; Zevenhoven, Ron [Laboratory of Energy Engineering and Environmental Protection, Helsinki University of Technology, P.O. Box 4400, FIN-02015 Espoo (Finland); Haapala, Matti [Temet Instruments OY, Pulttitie 8 A 1, FIN-00880, Helsinki (Finland)

    2004-08-01

    The effect of stabilizers on thermal degradation of poly(vinyl chloride) (PVC) in a bubbling fluidized bed (BFB) was studied as part of a process assessment for high-PVC waste treatment. The BFB reactor operated at temperatures between 200 and 400C and three types of PVC were used in the tests: a pure rigid bottle-grade containing some tin compounds stabilizer, an old, light grey sewage PVC pipe with lead compound stabilizer and a newer orange sewage PVC pipe with Ca/Zn compounds stabilizer. The pyrolysis gases from the BFB were analyzed with a Fourier transform infrared (FT-IR) spectrometer. The result from the tests and char analysis showed that the weight fraction and the type of stabilizer, especially lead compound, have a major effect by slowing PVC degradation especially at the first degradation stage compared to a purer PVC which contains only a small amount of tin based stabilizer. The results also showed that a temperature range 340-350C, where most of the chlorine for all types used in the tests was released, is optimal for operating the BFB pyrolysis reactor.

  1. The Artificial Gravity Bed Rest Pilot Project: Effects on Knee Extensor and Plantar Flexor Muscle Groups

    Science.gov (United States)

    Caiozzo, V. J.; Haddad, F.; Lee, S.; Baker, M.; Baldwin, K. M.

    2007-01-01

    The goal of this project was to examine the effects of artificial gravity (2.5 g) on skeletal muscle strength and key anabolic/catabolic markers known to regulate muscle mass. Two groups of subjects were selected for study: 1) a 21 day-bed rest (BR) control (C) group (N=7); and 2) an AG group (N=8), which was exposed to 21 days of bed-rest plus daily 1 hr exposures to AG (2.5 g). This particular experiment was part of an integrated AG Pilot Project sponsored by NASA/Johnson Space Center. The in vivo torque-velocity relationships of the knee extensors and plantar flexors of the ankle were determined pre and post treatment. Also, pre- and post treatment biopsy samples were obtained from both the vastus lateralis and soleus muscles and were used, in part, for a series of analyses on gene expression (mRNA abundance) of key factors implicated in the anabolic versus catabolic state of the muscle. Post/Pre toque-velocity determinations revealed greater decrements in knee extensor performance in the C versus AG group (P less than 0.04). The plantar flexor muscle group of the AG subjects actually demonstrated a net gain in torque-velocity relationship; whereas, in the C group the overall post/pre responses declined (AG vs C; P less than 0.001). Measurements of muscle fiber cross-sectional area (for both muscles) demonstrated a loss of approx. 20% in the C group while no losses were evident in the AG group. RT-PCR analyses of muscle biopsy specimens demonstrated that markers of growth and cytoskeletal integrity (IGF-1, IGF-1 BP4, mechano growth factor, total RNA, and pro-collagen 3a) were higher in the AG group, whereas catabolic markers (myostatin and atrogen) were elevated in the C group. Importantly, these patterns were seen in both muscles. Based on these observations we conclude that paradigms of AG have the potential to maintain the functional, biochemical, and structural homeostasis of skeletal muscle in the face of chronic unloading states. These findings also

  2. Effect of microflora of bed waters of the Arlan oil field on nonionogenic surfactant OP-10

    Energy Technology Data Exchange (ETDEWEB)

    Gvozdyak, P.I.; Khazipov, R.Kh.; Kravchuk, V.N.; Podorvan, N.I.; Udod, V.M.

    1983-01-01

    A study was made of the possibility of destruction of the nonionogenic surfactant (NS) OP-10 under the influence of microflora of bed waters of the Arlan field. It was established that in the studied water there is biocenosis of the microorganisms promoting destruction of NS OP-10 with initial concentration of 500 mg/l. The adapted biocenosis of the microorganisms of bed waters to OP-10 in anaerobic conditions destroys the compound by 79-85% in 6 days.

  3. Effects of head-down-tilt bed rest on cerebral hemodynamics during orthostatic stress

    Science.gov (United States)

    Zhang, R.; Zuckerman, J. H.; Pawelczyk, J. A.; Levine, B. D.; Blomqvist, C. G. (Principal Investigator)

    1997-01-01

    Our aim was to determine whether the adaptation to simulated microgravity (microG) impairs regulation of cerebral blood flow (CBF) during orthostatic stress and contributes to orthostatic intolerance. Twelve healthy subjects (aged 24 +/- 5 yr) underwent 2 wk of -6 degrees head-down-tilt (HDT) bed rest to simulate hemodynamic changes that occur when humans are exposed to microG. CBF velocity in the middle cerebral artery (transcranial Doppler), blood pressure, cardiac output (acetylene rebreathing), and forearm blood flow were measured at each level of a ramped protocol of lower body negative pressure (LBNP; -15, -30, and -40 mmHg x 5 min, -50 mmHg x 3 min, then -10 mmHg every 3 min to presyncope) before and after bed rest. Orthostatic tolerance was assessed by using the cumulative stress index (CSI; mmHg x minutes) for the LBNP protocol. After bed rest, each individual's orthostatic tolerance was reduced, with the group CSI decreased by 24% associated with greater decreases in cardiac output and greater increases in systemic vascular resistance at each level of LBNP. Before bed rest, mean CBF velocity decreased by 14, 10, and 45% at -40 mmHg, -50 mmHg, and maximal LBNP, respectively. After bed rest, mean velocity decreased by 16% at -30 mmHg and by 21, 35, and 39% at -40 mmHg, -50 mmHg, and maximal LBNP, respectively. Compared with pre-bed rest, post-bed-rest mean velocity was less by 11, 10, and 21% at -30, -40, and -50 mmHg, respectively. However, there was no significant difference at maximal LBNP. We conclude that cerebral autoregulation during orthostatic stress is impaired by adaptation to simulated microG as evidenced by an earlier and greater fall in CBF velocity during LBNP. We speculate that impairment of cerebral autoregulation may contribute to the reduced orthostatic tolerance after bed rest.

  4. The Effect of Tibial Posterior Slope on Contact Force and Ligaments Stresses in Posterior-Stabilized Total Knee Arthroplasty-Explicit Finite Element Analysis

    OpenAIRE

    Lee, Hwa-Yong; Kim, Sung-Jae; Kang, Kyoung-Tak; Kim, Sung-Hwan; Park, Kwan-Kyu

    2012-01-01

    Purpose The purpose of this study is to evaluate the effect of change in tibial posterior slope on contact force and ligament stress using finite element analysis. Materials and Methods A 3-dimensional finite element model for total knee arthroplasty was developed by using a computed tomography scan. For validation, the tibial translations were compared with previous studies. The finite element analysis was conducted under the standard gait cycle, and contact force on ultra-high molecular wei...

  5. Effect of Posterior Femoral Condylar Offset and Posterior Tibial Slope on Maximal Flexion Angle of the Knee in Posterior Cruciate Ligament Sacrificing Total Knee Arthroplasty

    OpenAIRE

    Kim, Jong-Heon

    2013-01-01

    Purpose To evaluate the effect of femoral condylar offset and posterior tibial slope on maximal flexion angle of the knee in posterior cruciate ligament (PCL)-sacrificing total knee arthroplasty (TKA, Medial-Pivot Knee System). Materials and Methods Forty-five knees in 35 patients who could be followed up more than 1 year after PCL-sacrificing TKA were evaluated retrospectively. We measured and analyzed the preoperative and postoperative maximal flexion angle, posterior femoral condylar offse...

  6. Effect of Slope Position on Soil Properties and Types Along an Elevation Gradient of Arasbaran Forest, Iran

    OpenAIRE

    Hossein Rezaei; Ali Asghar Jafarzadeh; Ahmad Alijanpour; Farzin Shahbazi; Khalil Valizadeh Kamran

    2015-01-01

    Sustainable development by forest managing need to identify forest ecosystem elements. Forest soil is the most important element of forest ecosystem that has key roles in forest managing. Therefore, studying of soil properties and evolution under different environmental conditions is necessary for sustainable management of forest ecosystems. Spatial variation of soil properties is significantly influenced by some environmental factors that slope position is one of them. The aim of this study ...

  7. Ability of bed bug-detecting canines to locate live bed bugs and viable bed bug eggs.

    Science.gov (United States)

    Pfiester, Margie; Koehler, Philip G; Pereira, Roberto M

    2008-08-01

    The bed bug, Cimex lectularius L., like other bed bug species, is difficult to visually locate because it is cryptic. Detector dogs are useful for locating bed bugs because they use olfaction rather than vision. Dogs were trained to detect the bed bug (as few as one adult male or female) and viable bed bug eggs (five, collected 5-6 d after feeding) by using a modified food and verbal reward system. Their efficacy was tested with bed bugs and viable bed bug eggs placed in vented polyvinyl chloride containers. Dogs were able to discriminate bed bugs from Camponotus floridanus Buckley, Blattella germanica (L.), and Reticulitermes flavipes (Kollar), with a 97.5% positive indication rate (correct indication of bed bugs when present) and 0% false positives (incorrect indication of bed bugs when not present). Dogs also were able to discriminate live bed bugs and viable bed bug eggs from dead bed bugs, cast skins, and feces, with a 95% positive indication rate and a 3% false positive rate on bed bug feces. In a controlled experiment in hotel rooms, dogs were 98% accurate in locating live bed bugs. A pseudoscent prepared from pentane extraction of bed bugs was recognized by trained dogs as bed bug scent (100% indication). The pseudoscent could be used to facilitate detector dog training and quality assurance programs. If trained properly, dogs can be used effectively to locate live bed bugs and viable bed bug eggs. PMID:18767752

  8. Effects of seagrass bed removal for tourism purposes in a Mauritian bay

    International Nuclear Information System (INIS)

    Tourism affects marine environments adversely and these effects may be a major threat to the future of tourism. - Stresses and shocks are increasing on the main natural assets in Mauritius (Western Indian Ocean) by tourism (marine-based) development activities. Seagrasses are removed by hotels in the belief that they are unsightly or harbour organisms causing injury to bathers. Environmental changes (e.g. sediment characteristics and infauna distribution, water quality, seagrass biomass) resulting from clearing of a seagrass bed to create an aesthetically pleasant swimming zone for clients of a hotel were monitored during June 2000-July 2001, and compared to conditions prevailing in an adjacent undisturbed area. Key observations in the disturbed area were: highly turbid water overlying a destabilized lagoon seabed, complete loss of sediment infauna, and dramatic dry weight biomass declines (e.g. 72 and 65% in S. isoetifolium and H. uninervis, respectively). Such disruptions draw-down resilience rendering the marine habitats less robust and more vulnerable to environmental change and extreme events, with higher risks of chaos and ecological collapse, and constitute a major threat to the industry itself

  9. Effect of hydraulic retention time on metal precipitation in sulfate reducing inverse fluidized bed reactors

    KAUST Repository

    Villa-Gómez, Denys Kristalia

    2014-02-13

    BACKGROUND: Metal sulfide recovery in sulfate reducing bioreactors is a challenge due to the formation of small precipitates with poor settling properties. The size of the metal sulfide precipitates with the change in operational parameters such as pH, sulfide concentration and reactor configuration has been previously studied. The effect of the hydraulic retention time (HRT) on the metal precipitate characteristics such as particle size for settling has not yet been addressed. RESULTS: The change in size of the metal (Cu, Zn, Pb and Cd) sulfide precipitates as a function of the HRT was studied in two sulfate reducing inversed fluidized bed (IFB) reactors operating at different chemical oxygen demand concentrations to produce high and low sulfide concentrations. The decrease of the HRT from 24 to 9h in both IFB reactors affected the contact time of the precipitates formed, thus making differences in aggregation and particle growth regardless of the differences in sulfide concentration. Further HRT decrease to 4.5h affected the sulfate reducing activity for sulfide production and hence, the supersaturation level and solid phase speciation. Metal sulfide precipitates affected the sulfate reducing activity and community in the biofilm, probably because of the stronger local supersaturation causing metal sulfides accumulation in the biofilm. CONCLUSIONS: This study shows that the HRT is an important factor determining the size and thus the settling rate of the metal sulfides formed in bioreactors.

  10. Effects of age and inactivity due to prolonged bed rest on atrophy of trunk muscles.

    Science.gov (United States)

    Ikezoe, Tome; Mori, Natsuko; Nakamura, Masatoshi; Ichihashi, Noriaki

    2012-01-01

    This study investigated the effects of age and inactivity due to being chronically bedridden on atrophy of trunk muscles. The subjects comprised 33 young women (young group) and 41 elderly women who resided in nursing homes or chronic care institutions. The elderly subjects were divided into two groups: independent elderly group who were able to perform activities of daily living involving walking independently (n = 28) and dependent elderly group who were chronically bedridden (n = 13). The thickness of the following six trunk muscles was measured by B-mode ultrasound: the rectus abdominis, external oblique, internal oblique, transversus abdominis, thoracic erector spinae (longissimus) and lumbar multifidus muscles. All muscles except for the transversus abdominis and lumbar multifidus muscles were significantly thinner in the independent elderly group compared with those in the young group. The thicknesses of all muscles in the dependent elderly group was significantly smaller than that in the young group, whereas there were no differences between the dependent elderly and independent elderly groups in the muscle thicknesses of the rectus abdominis and internal oblique muscles. In conclusion, our results suggest that: (1) age-related atrophy compared with young women was less in the deep antigravity trunk muscles than the superficial muscles in the independent elderly women; (2) atrophy associated with chronic bed rest was more marked in the antigravity muscles, such as the back and transversus abdominis. PMID:21472438

  11. Effects of seagrass bed removal for tourism purposes in a Mauritian bay

    Energy Technology Data Exchange (ETDEWEB)

    Daby, D

    2003-10-01

    Tourism affects marine environments adversely and these effects may be a major threat to the future of tourism. - Stresses and shocks are increasing on the main natural assets in Mauritius (Western Indian Ocean) by tourism (marine-based) development activities. Seagrasses are removed by hotels in the belief that they are unsightly or harbour organisms causing injury to bathers. Environmental changes (e.g. sediment characteristics and infauna distribution, water quality, seagrass biomass) resulting from clearing of a seagrass bed to create an aesthetically pleasant swimming zone for clients of a hotel were monitored during June 2000-July 2001, and compared to conditions prevailing in an adjacent undisturbed area. Key observations in the disturbed area were: highly turbid water overlying a destabilized lagoon seabed, complete loss of sediment infauna, and dramatic dry weight biomass declines (e.g. 72 and 65% in S. isoetifolium and H. uninervis, respectively). Such disruptions draw-down resilience rendering the marine habitats less robust and more vulnerable to environmental change and extreme events, with higher risks of chaos and ecological collapse, and constitute a major threat to the industry itself.

  12. Effect of sulfide concentration on the location of the metal precipitates in inversed fluidized bed reactors

    International Nuclear Information System (INIS)

    Highlights: → Sulfide concentration governs the location of metal precipitates in sulfate reducing bioreactors. → High dissolved sulfide induces metal precipitation in the bulk liquid as fines. → Low dissolved sulfide concentrations yield local supersaturation and thus metal precipitation in the biofilm. -- Abstract: The effect of the sulfide concentration on the location of the metal precipitates within sulfate-reducing inversed fluidized bed (IFB) reactors was evaluated. Two mesophilic IFB reactors were operated for over 100 days at the same operational conditions, but with different chemical oxygen demand (COD) to SO42- ratio (5 and 1, respectively). After a start up phase, 10 mg/L of Cu, Pb, Cd and Zn each were added to the influent. The sulfide concentration in one IFB reactor reached 648 mg/L, while it reached only 59 mg/L in the other one. In the high sulfide IFB reactor, the precipitated metals were mainly located in the bulk liquid (as fines), whereas in the low sulfide IFB reactor the metal preciptiates were mainly present in the biofilm. The latter can be explained by local supersaturation due to sulfide production in the biofilm. This paper demonstrates that the sulfide concentration needs to be controlled in sulfate reducing IFB reactors to steer the location of the metal precipitates for recovery.

  13. A Green Roof Test Bed for Stormwater Management and Reduction of Urban Heat Island Effect in Singapore

    OpenAIRE

    Qin, Xiaosheng; Wu, Xiangyu; Yee-Meng CHIEW; Li, Yanhong

    2013-01-01

    A green roof test bed, established at the Nanyang Technological University in Singapore, was used to investigate its benefit for storm water management and urban heat island effect mitigation. The system comprised 3 units, 2 in the form of vegetated roofs and the other a bare roof. The system was equipped with automatic monitoring devices for measuring the hydrological data. Continuous data monitoring on the roofs was conducted to evaluate the thermal and hydrological effects. The study shows...

  14. Effects of daily mild supine exercise on physical performance after 20 days bed rest in young persons

    Science.gov (United States)

    Suzuki, Y.; Kashihara, H.; Takenaka, K.; Kawakubo, K.; Makita, Y.; Goto, S.; Ikawa, S.; Gunji, A.

    To investgate the effects of daily mild supine exercise on physical performance capacity identified as maximal oxygen uptake rate (VO 2max) after 20 days bed-rest, 3 male students performed a supine pedaling at 40 % intensity of VO 2max for one hour every day, while 6 male and 5 female students were control. Before and after the bed-rest, muscle mass and strength of exercising leg and cardio-vascular responses during -40 mmHg lower body negative pressure (LBNP) and moderate upright cycling exercise were measured. Despite the exercise programme VO 2max was similarly decreased to the control subjects after the bed-rest. The delta VO 2max was correlated to delta % left ventricular fractional shortening during LBNP, and also % delta VO 2max to % delta stroke volume of the moderate exercise (both pexercise programme should be too weak to maintain cardiovascular functions and thus to present the decrease in VO 2max against pro-longed bed-rest as well as weightlessness stress.

  15. Effective Thermal Property Estimation of Unitary Pebble Beds Based on a CFD-DEM Coupled Method for a Fusion Blanket

    Science.gov (United States)

    Chen, Lei; Chen, Youhua; Huang, Kai; Liu, Songlin

    2015-12-01

    Lithium ceramic pebble beds have been considered in the solid blanket design for fusion reactors. To characterize the fusion solid blanket thermal performance, studies of the effective thermal properties, i.e. the effective thermal conductivity and heat transfer coefficient, of the pebble beds are necessary. In this paper, a 3D computational fluid dynamics discrete element method (CFD-DEM) coupled numerical model was proposed to simulate heat transfer and thereby estimate the effective thermal properties. The DEM was applied to produce a geometric topology of a prototypical blanket pebble bed by directly simulating the contact state of each individual particle using basic interaction laws. Based on this geometric topology, a CFD model was built to analyze the temperature distribution and obtain the effective thermal properties. The current numerical model was shown to be in good agreement with the existing experimental data for effective thermal conductivity available in the literature. supported by National Special Project for Magnetic Confined Nuclear Fusion Energy of China (Nos. 2013GB108004, 2015GB108002, 2014GB122000 and 2014GB119000), and National Natural Science Foundation of China (No. 11175207)

  16. Maximum spoutable bed height of spout-fluid bed

    Energy Technology Data Exchange (ETDEWEB)

    Wenqi Zhong; Mingyao Zhang; Baosheng Jin [Southeast University, Nanjing (China). Key Laboratory on Clean Coal Power Generation and Combustion Technology of Ministry of Education

    2006-11-15

    Experimental study on the maximum spoutable bed height of a spout-fluid bed (cross-section of 0.3 m x 0.03 m and height of 2 m) packed with Geldart group D particles has been carried out. The effects of particle size, spout nozzle size and fluidizing gas flow rate on the maximum spoutable bed height were studied. Experimental data were compared to some published experiments and predictions. The results show that the maximum spoutable bed height of spout-fluid bed decreases with increasing particle size and spout nozzle size, which appears the same trend to that of spouted beds. The increasing of fluidizing gas flow rate leads to a sharply decrease in the maximum spoutable bed height. The existent correlations of the maximum spoutable bed height in the literature were observed to involve large discrepancies. Additionally, the flow characteristics when bed materials deeper than the maximum spoutable height were summarized. Under this condition, the spout-fluid bed operated without a stable and coherent spout or fountain assembles the characteristics of jetting fluidized bed. Besides, the mechanisms of spout termination were investigated. It was found that slugging in the spout and growth of instabilities would cause the spout termination in spout-fluid bed.

  17. Geomorphic effects of wood quantity and characteristics in three Italian gravel-bed rivers

    Science.gov (United States)

    Ravazzolo, D.; Mao, L.; Picco, L.; Sitzia, T.; Lenzi, M. A.

    2015-10-01

    In-channel wood is a fundamental component of the riverine system. Its nature, abundance, and distribution as well as the role of wood in trapping sediment have been reported by many authors. However, a lack of knowledge still exists on how the geomorphic effects, quantity, and characteristics of in-channel wood may be altered by different human pressures. For this reason, in-channel wood was surveyed in the Brenta, Piave, and Tagliamento gravel-bed rivers (northeastern Italy), which are altered by different degrees of human pressures. Both single pieces of wood (> 0.1 m diameter, and/or > 1 m long) and accumulations of large wood were measured on cross sectional transects within the active channels. Overall, 3430 (8.4, 13.9 and 10.7 elements/ha in the Brenta, Piave, and Tagliamento rivers, respectively) of isolated pieces and 591 (9.8, 15.0, and 11.0 wood accumulations/ha in the Brenta, Piave, and Tagliamento rivers, respectively) accumulations were surveyed in the study sites. In the Brenta and Piave rivers, which feature the greater human pressures, logs appear in a worse state of conservation. In the less disturbed Tagliamento River, the logs appear to be smaller and in a better state of conservation with higher capacity for resprouting. In addition, higher geomorphic interactions were found between wood and sediments in the Tagliamento River. Because of its ability to create geomorphic effects, in-channel wood represents an important source of complexity that can increase habitat diversity in river systems. A better knowledge of the role of human disturbances on the characteristics and abundance of large wood in river systems could help in developing better river management and the practical application of river ecology.

  18. Effects of hypocretin and norepinephrine interaction in bed nucleus of the stria terminalis on arterial pressure.

    Science.gov (United States)

    Ciriello, J; Caverson, M M; Li, Z

    2013-01-01

    Forebrain neuronal circuits containing hypocretin-1 (hcrt-1) and norepinephrine (NE) are important components of central arousal-related processes. Recently, these two systems have been shown to have an overlapping distribution within the bed nucleus of the stria terminalis (BST), a limbic structure activated by stressful challenges, and which functions to adjust arterial pressure (AP) and heart rate (HR) to the stressor. However, whether hcrt-1 and NE interact in BST to alter cardiovascular function is unknown. Experiments were done in urethane-α-chloralose anesthetized, paralyzed, and artificially ventilated male Wistar rats to investigate the effect of hcrt-1 and NE on the cardiovascular responses elicited by l-glutamate (Glu) stimulation of BST neurons. Microinjections of hcrt-1, NE or tyramine into BST attenuated the decrease in AP and HR to Glu stimulation of BST. Additionally, combined injections of hcrt-1 with NE or tyramine did not elicit a greater attenuation than either compound alone. Furthermore, injections into BST of the α2-adrenergic receptor (α2-AR) antagonist yohimbine, but not the α1-AR antagonist 2-{[β-(4-hydroxyphenyl)ethyl]aminomethyl}-1-tetralone hydrochloride, blocked both the hcrt-1 and NE-induced inhibition of the BST cardiovascular depressors responses. Finally, injections into BST of the GABAA receptor antagonist bicuculline, but not the GABAB receptor antagonist phaclofen, blocked the hcrt-1 and NE attenuation of the BST Glu-induced depressor and bradycardia responses. These data suggest that hcrt-1 effects in BST are mediated by NE neurons, and hcrt-1 likely acts to facilitate the synaptic release of NE. NE neurons, acting through α2-AR may activate Gabaergic neurons in BST, which in turn through the activation of GABAA receptors inhibit a BST sympathoinhibitory pathway. Taken together, these data suggest that hcrt-1 pathways to BST through their interaction with NE and Gabaergic neurons may function in the coordination of

  19. DISSIPATION OF WAVE ENERGY ON VERY MILD SLOPE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper presents the analysis and calculation of wave attenuation when waves travel on sand bed, sand ripple bed and muddy bed, respectively. The study shows that (1) The dissipation of wave energy due to bottom percolation may be neglected on sand bed; (2) The wave attenuation due to the friction of sand ripples is one order higher than that of flat sand bed and (3) The energy loss of waves propagating on muddy bed is the largest. Then, the equivalent coefficients of friction are calculated in order to compare with the solution by the bottom-friction model. Wave attenuation are also computed by the Bingham-model and the principle of conservation of wave energy flux on very mild muddy slope. The results coincide well with the wave information from the Lianyungang Wave Observation Station. Theoretical prediction proves that the equivalent coefficients of friction strongly rely on water depth, which inerease with decreasing depth.

  20. Effect of Vegetation and Precipitation upon Runoff and Sediment Production on Slope Lands of the Loess Area in China

    Institute of Scientific and Technical Information of China (English)

    WU Sihong; ZHANG Xiaoming; ZHU Qinke

    2006-01-01

    According to fixed-position data for 1992-2003 from 16 runoff plots of Caijiachuan watershed which lie in Jixian County,Shanxi Province,in the loess area,this paper studied the relationship between vegetation and runoff and sediment production on slope lands.The results showed as follows:1)Runoff and sediment production in Robinia pseudoacacia forest and Pinus tabulaeformis forest had a high correlation with precipitation amount and rainfall intensity,but the correlation decreased gradually with the increase of canopy density;2)The secondary forest had better function of soil and water conservation than artificial R.pseudoacacia forest,and runoff and sediment production in the former in an individual rain event was 65%-82% and 23%-92% lower than those in the latter,respectively;3)The difference of runoff and sediment production in several land uses was very distinct.Runoff and sediment production in Ostryopsis davidiana forest and the secondary forest were the least;runoff and sediment production in artificial R.pseudoacacia forest and P. tabulaeformis forest were 5-fold as much as those in O.davidiana forest.Besides.runoff and sediment production in mixed stand of apple trees and crops were 16.14-fold and 2.96-fold higher than that in O.davidiana forest,respectively,but the amount decreased obviously after high-standard soil preparation for the former;4)Based on gray correlation analysis of various factors affecting runoff and sediment production on slope lands,it can be seen that stand canopy density and herb and litter biomass were the most significant ones,whose gray correlation values all exceeded 0.6.Therefore.mixed forest with multi-layer stand structure and shrub forest should be developed in vegetation reconstruction of the loess area,which help to increase coverage and litter thickness to cut down the runoff and sediment production dramatically on slope lands.

  1. Elastic slopes and diffraction

    International Nuclear Information System (INIS)

    It is well known that elastic hadronic slopes grow with energy and appear sizeably larger when measured very close to t=0 than at intermediate t-values. This has been confirmed by the recent anti-p p measurements at the CERN SPS-Collider. By comparing the data with a formula derived recently which gives the slope as a function of the four momentum transfer squared t and of the average multiplicity we argue that all the basic properties of hadronic slopes may be attributed to the role of multiparticle unitarity, i.e. to diffraction

  2. Covers of Elliptic Curves and the Lower Bound for Slopes of Effective Divisors on $\\bar{\\mathcal M}_{g}$

    OpenAIRE

    Chen, Dawei

    2007-01-01

    Consider genus $g$ curves that admit degree $d$ covers to elliptic curves only branched at one point with a fixed ramification type. The locus of such covers forms a one parameter family $Y$ that naturally maps into the moduli space of stable genus $g$ curves $\\bar{\\mathcal M}_{g}$. We study the geometry of $Y$, and produce a combinatorial method by which to investigate its slope, irreducible components, genus and orbifold points. As a by-product of our approach, we find some equalities from ...

  3. Agro-industrial waste: a low cost adsorbent for effective removal of 4-chloro-2-methylphenoxyacetic acid herbicide in batch and packed bed modes.

    Science.gov (United States)

    Deokar, Sunil K; Mandavgane, Sachin A; Kulkarni, Bhaskar D

    2016-08-01

    The present work describes the aqueous phase removal of 4-chloro-2-methylphenoxyacetic acid herbicide by rice husk ash (RHA) using batch and packed bed adsorption techniques. The effects of dosage, initial concentration, time, pH, temperature, and particle size of adsorbent in batch compared with effects of influent concentration, flow rate, and bed height in packed bed were studied. The particle size effect reveals that the removal is dependent on chemical composition (silica and carbon content) together with BET surface area of RHA. The aptness of Langmuir isotherm to batch data indicates the favorable adsorption whereas that of Temkin isotherm informs the heterogeneous nature of RHA. The kinetics of adsorption follows the pseudo-second order and Elovich models while thermodynamics of process indicates the exothermic adsorption. Among the models applied in packed bed study, the deactivation kinetic, Yoon-Nelson and bed depth service time (BDST) models are suitable to explain the packed bed adsorption. The adsorption capacity of RHA in packed bed study is found greater than that in batch. The adsorption capacity of RHA determined by the BDST model is 3019 mg/L for 90 % saturation of bed. The adsorption capacity of RHA based on weight is ∼2.3 times and that based on surface area is ∼55.55 times greater than that of granular activated carbon. PMID:27151241

  4. Mass balance and isotope effects during nitrogen transport through septic tank systems with packed-bed (sand) filters

    Science.gov (United States)

    Hinkle, S.R.; Böhlke, J.K.; Fisher, L.H.

    2008-01-01

    Septic tank systems are an important source of NO3- to many aquifers, yet characterization of N mass balance and isotope systematics following septic tank effluent discharge into unsaturated sediments has received limited attention. In this study, samples of septic tank effluent before and after transport through single-pass packed-bed filters (sand filters) were evaluated to elucidate mass balance and isotope effects associated with septic tank effluent discharge to unsaturated sediments. Chemical and isotopic data from five newly installed pairs and ten established pairs of septic tanks and packed-bed filters serving single homes in Oregon indicate that aqueous solute concentrations are affected by variations in recharge (precipitation, evapotranspiration), NH4+ sorption (primarily in immature systems), nitrification, and gaseous N loss via NH3 volatilization and(or) N2 or N2O release during nitrification/denitrification. Substantial NH4+ sorption capacity was also observed in laboratory columns with synthetic effluent. Septic tank effluent ??15N-NH4+ values were almost constant and averaged + 4.9??? ?? 0.4??? (1 ??). In contrast, ??15N values of NO3- leaving mature packed-bed filters were variable (+ 0.8 to + 14.4???) and averaged + 7.2??? ?? 2.6???. Net N loss in the two networks of packed-bed filters was indicated by average 10-30% decreases in Cl--normalized N concentrations and 2-3??? increases in ??15N, consistent with fractionation accompanying gaseous N losses and corroborating established links between septic tank effluent and NO3- in a local, shallow aquifer. Values of ??18O-NO3- leaving mature packed-bed filters ranged from - 10.2 to - 2.3??? (mean - 6.4??? ?? 1.8???), and were intermediate between a 2/3 H2O-O + 1/3 O2-O conceptualization and a 100% H2O-O conceptualization of ??18O-NO3- generation during nitrification.

  5. The effects of temperatures on the pebble flow in a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    The core of a pebble bed high temperature reactor (PBHTR) moves during operation, a feature which leads to better fuel economy (online refueling with no burnable poisons) and lower fuel stress. The pebbles are loaded at the top and trickle to the bottom of the core after which the burnup of each is measured. The pebbles that are not fully burned are recirculated through the core until the target burnup is achieved. The flow pattern of the pebbles through the core is of importance for core simulations because it couples the burnup distribution to the core temperature and power profiles, especially in cores with two or more radial burnup 'zones '. The pebble velocity profile is a strong function of the core geometry and the friction between the pebbles and the surrounding structures (other pebbles or graphite reflector blocks). The friction coefficient for graphite in a helium environment is inversely related to the temperature. The Thorium High Temperature Reactor (THTR) operated in Germany between 1983 and 1989. It featured a two-zone core, an inner core (IC) and outer core (OC), with different fuel mixtures loaded in each zone. The rate at which the IC was refueled relative to the OC in THTR was designed to be 0.56. During its operation, however, this ratio was measured to be 0.76, suggesting the pebbles in the inner core traveled faster than expected. It has been postulated that the positive feedback effect between inner core temperature, burnup, and pebble flow was underestimated in THTR. Because of the power shape, the center of the core in a typical cylindrical PBHTR operates at a higher temperature than the region next to the side reflector. The friction between pebbles in the IC is lower than that in the OC, perhaps causing a higher relative flow rate and lower average burnup, which in turn yield a higher local power density. Furthermore, the pebbles in the center region have higher velocities than the pebbles next to the side reflector due to the

  6. Effect of antiorthostatic bed rest on hepatic blood flow in man

    Science.gov (United States)

    Putcha, L.; Cintron, N. M.; Vanderploeg, J. M.; Chen, Y.; Habis, J.

    1988-01-01

    Physiological changes that occur during exposure to weightlessness may induce alterations in blood flow to the liver. Estimation of hepatic blood flow (HBF) using ground-based weightlessness simulation models may provide insight into functional changes of the liver in crewmembers during flight. In the present study, HBF, indirectly estimated by indocyanine gree (ICG) clearance, is compared in 10 subjects during the normal ambulatory condition and antiorthostatic (-6 deg) bed rest. Plasma clearance of ICG was determined following intravenous administration of a 0.5-mg/kg dose of ICG to each subject on two separate occasions: once after being seated for 1 h, and once after 24 h of head-down bed rest. After 24 h of head-down bed rest, hepatic blood flow did not change significantly from the respective control value.

  7. Effect of radiation reflected from the sea on the spectrum of diffuse radiation at the canopy of orchard on the slope facing to the sea

    International Nuclear Information System (INIS)

    In order to investigation the effect of radiation reflected from the sea on the spectrum of diffuse radiation at the canopy of orchard, spectral radiance of the sea, sky and canopies of orange orchard were measured with a spectrophotometer on the slope facing to the sea. Diffuse spectral irradiance on the sea side of the canopy was also measured.The spectral pattern of the radiance of the sea was similar to that of the sky; photosynthetically active radiation (PAR, 400-700nm) dominated to near infrared radiation (NIR, 700-1100nm). In the radiance of the canopy, however, NIR dominated. PAR in diffuse radiation reaching the canopy was enriched more by the reflected radiation of the sea than by that of the canopy. The radiance of the sea reached its maximum near sunset when the reflection became specular. PAR in diffuse radiation at the canopy was greater by 8.7% at the high elevation (240m above sea level) that at the low elevation (110m). The corresponding shape factors of the sea for the high and low elevations which were calculated based on photographs were 0.072 and 0.048 respectively, suggesting that PAR in diffuse radiation on slope could be reflected as a function of a shape factor of the sea.The enrichment of PAR in diffuse radiation by the reflected radiation of the sea may suggest the light condition of the orchard on the slope facing to the sea would become favorable for photosynthesis. (author)

  8. Heat Transfer in Segregated Fluidized Beds Part 2: Particle Motion and Its Effects on the Heat transfer in the Segregated Fluidized Beds

    Science.gov (United States)

    Gu, Yihua; Satoh, Isao; Saito, Takushi; Kawaguchi, Tatsuya

    In our previous paper, particle and temperature segregations in a fluidized bed of binary particle mixtures were experimentally examined, and heat transfer in the segregated fluidized bed was investigated. As the results, it was shown that the temperature segregation results mainly from low heat transfer coefficient through the interface layer, which exists between the flotsam-rich and jetsam-rich layers, and that the heat transfer coefficient increases rapidly with increasing the excess gas velocity. Following our previous paper, particle motion in the segregated fluidized bed was experimentally investigated in this paper, in order to make quantitative discussion on the relation between the heat transfer coefficient and particle motion in the interface layer. In the experiment, the Particle Imaging Velocimetry (PIV) method was applied to study the concentration and motion of particles in the segregated fluidized bed. A modified solid circulation model was built up to model the particle motion in the segregated fluidized bed. The experiment results showed that the vertical particle exchange rate of the interface layer increases with the excess gas velocity, and that the vertical heat transfer coefficient through the interface layer is mainly determined by the average particle exchange rate in the interface layer. Variations of the apparent thermal conductivity at different height in the particle layers were also determined by the vertical variation of the particle exchange rate. It was shown that the heat transfer coefficient or the thermal conductivity in the interface layer is influenced by the densities and specific heat capacities of the particles.

  9. Effect of non-uniform porosity distribution on thermalhydraulics in a pebble bed reactor

    International Nuclear Information System (INIS)

    In pebble bed reactors, the porosity profile shows strong fluctuations near the wall. These changes in fuel density affect local power density, coolant velocity, and temperature distribution. This paper describes the pebFoam code, capable of calculating pebble bed thermohydraulics including non-uniform porosity distributions for arbitrary geometries, and investigates the changes in velocity, pressure drop, and helium and pebble temperatures when using a nonuniform porosity distribution instead of a uniform distribution. Results show only minor changes in temperature profiles and pressure drop for full power steady state calculations, though the velocity profile shows a clear increase in velocity near the wall. (author)

  10. Nitrate removal, communities of denitrifiers and adverse effects in different carbon substrates for use in denitrification beds

    OpenAIRE

    Warneke, Sören; Schipper, Louis A.; Matiasek, Michael G.; Scow, Kate M.; Cameron, Stewart; Bruesewitz, Denise A.; McDonald, Ian R.

    2011-01-01

    Denitrification beds are containers filled with wood by-products that serve as a carbon and energy source to denitrifiers, which reduce nitrate ( NO3−) from point source discharges into non-reactive dinitrogen (N2) gas. This study investigates a range of alternative carbon sources and determines rates, mechanisms and factors controlling NO3− removal, denitrifying bacterial community, and the adverse effects of these substrates. Experimental barrels (0.2 m3) filled with either maize cobs, w...

  11. New Momentum and Energy Balance Equations Considering Kinetic Energy Effect for Mathematical Modelling of a Fixed Bed Adsorption Column

    OpenAIRE

    Luberti, Mauro; Kim, Yo Han; Lee, Chang-Ha; Ferrari, Maria-Chiara; Ahn, Hyungwoong

    2015-01-01

    It was aimed to derive rigorous momentum and energy balance equations where the change of kinetic energy in both spatial and temporal domains of a fixed-bed adsorption column was newly taken into account. While the effect of kinetic energy on adsorption column dynamics is negligible in most cases, it can become more and more influential with an adsorption column experiencing a huge pressure drop or with the gas velocity changing abruptly with time and along the column. The rigorous momentum a...

  12. Effects of erosion in the fate of soil organic carbon and soil aggregation in a burned Mediterranean hill-slope

    Science.gov (United States)

    Campo, Julian; Cammeraat, Erik; Gimeno-García, Eugenia; Andreu, Vicente

    2016-04-01

    The Intergovernmental Panel on Climate Change indicated a higher degree of confidence that meteorological conditions associated to climate change will be propitious to increasing extreme events manifested, among others, in bigger and more frequent wildfires (IPCC, 2014). Wildfires contribute to shaping the landscape, and also the geomorphological and hydrological processes that operate on soil are affected (Bento-Gonçalves et al., 2012). Whereas, it is well documented that wildfires produce significant changes on erosion processes, the associated fate of soil organic carbon (SOC) has received less attention. This research assesses this gap by studying the loss, redistribution, and stabilization of SOC in a Mediterranean forest hill-slope burned the 28-08-2014, with high severity fire, at the Natural Park of Sierra de Espadán, Spain (39°50'45.11"N, 0°22'20.52"W). To this end, soil was sampled (19-9-2014) in the foot's slope (depositional), middle part (transport) and top (eroding) at two depths (burned areas experiencing soil erosion, transport and deposition, with special attention to the role of aggregation and disaggregation in redistribution processes. Immediately after the fire, SOC content was high (≈50 gC kg-1) as well as the AS (water drop test>146 drops). Significant differences (ANOVA, pBS) and soil depths (topsoil>subsoil). However, no significant differences were observed among eroding (58.8+20.8 gC kg-1), transport (67.3+34.4 gC kg-1), and depositional zones (62.0+31.3 gC kg-1), which is not in agreement with other SOC redistribution studies (Wang et al., 2014). Significant differences (Kruskal-Wallis, pBS) but not between soil depths or hill-slope positions. In the first post-fire erosive rains occurred in the area (29-11-14), closest pluviometer (Sot de Ferrer: 4.5 km) registered a total daily rain up to 64.2 l m-2. In this event a total of 12.7 kg of sediment were collected (contributing area ≈0.25 ha), with a content of 252.6 gC kg-1 the

  13. Effect of different carriers and operating parameters on degradation of flax wastewater by fluidized-bed Fenton process.

    Science.gov (United States)

    Chen, Mengtian; Ren, Hongqiang; Ding, Lili; Gao, Baotian

    2015-01-01

    This investigation evaluates the effectiveness of a fluidized-bed Fenton process in treating flax wastewater. Flax wastewater was taken from a paper-making factory in a secondary sedimentation tank effluent of a paper-making factory in Hebei. The performance of three carriers (SiO2, Al2O3, Fe2O3) used in the reactor was compared, and the effects of different operational conditions, and Fenton reagent concentrations were studied. Experimental results indicated that SiO2 was the most appropriate carrier in the system. The dose of Fe2+ and H2O2 was a significant operating factor in the degradation progress. The bed expansion was considered to be another factor influencing the treatment effect. Under the appropriate conditions (300 mg/L Fe2+, 600 mg/L H2O2, and 74.07 g/L SiO2 as the carrier, at pH=3, 50% bed expansion), the highest removal rate of total organic carbon (TOC) and color was 89% and 94%, respectively. The article also discussed the process of the colority removal of flax wastewater and the kinetics of TOC removal. PMID:26067494

  14. Effects of Adding Corn Dried Distiller Grains with Solubles (DDGS) to the Dairy Cow Diet and Effects of Bedding in Dairy Cow Slurry on Fugitive Methane Emissions

    OpenAIRE

    Daniel I. Massé; Guillaume Jarret; Chaouki Benchaar; Fadi Hassanat

    2014-01-01

    Simple Summary The objectives of this experiment were to investigate the effects of adding corn DDGS to the dairy cow diet as well as the bedding types (wood shavings, straw or peat moss) on manure fugitive CH4 emissions. The incorporation of DDGS in the diet has increased manure methane emission by 15% and the use of peat moss as bedding has increased manure methane emission by 27%. Abstract The specific objectives of this experiment were to investigate the effects of adding 10% or 30% corn ...

  15. Flow of River Tigris and its Effect on the Bed Sediment within Baghdad, Iraq

    Science.gov (United States)

    Al-Ansari, Nadhir; Ali, Ammar A.; Al-Suhail, Qusay; Knutsson, Sven

    2015-12-01

    River Tigris is a major river in Iraq. Sediment at the bed of the river within a reach of about 18 km from the center of Baghdad upstream was investigated. Sixty five cross sections were surveyed, and 46 sediment samples were collected and analyzed. It was noticed that fine sand was dominant in the bed (90.74%). The average median size within the reach was 2.49 phi (0.177 mm), while the mean size was 2.58 phi (0.16 mm). In addition, the sediments were moderately sorted, fine skewed and leptokurtic. The size of the bed sediment decreased relative to previous investigations due to the construction of the Adhaim dam on tributary, which used to be the main sediment supplier to the Tigris River before entering Baghdad. Furthermore, the discharge of the Tigris River for the period 1983-2013 (715 m3/s) decreased by about 40% and 30%since 1983when compared with the periods 1931-1956 (1208 m3/s) and 1956-1980 (1015 m3/s), respectively, due to climate change and construction of dams upstream from Baghdad. This has decreased the capacity and the competence of the river. The bed elevation has increased compared to previous surveys. Itwas noticed that dredging operations and obstructions (e.g. fallen bridges and islands) have disturbed the flow of the river and sediment characteristics in several sites.

  16. Coal-bed methane water effects on dill and essential oils

    Science.gov (United States)

    Pumping water from coal seams decreases the pressure in the seam and in turn releases trapped methane; this is the most common and economic way of methane extraction. The water that is pumped out is known as coal-bed methane water (CBMW), which is high in sodium and other salts. In past 25 years, th...

  17. Effect of a peripheral gas supply on the hydrodynamics of a spouting bed

    Science.gov (United States)

    Akulich, P. V.

    1994-07-01

    The results of experimental investigations of the resistance of a pyramidal spouting bed with a peripheral gas supply are discussed, including the rates at the beginning and end of the process of spouting and material entrainment from an apparatus. Data is generalized in the form of dimensionless relations.

  18. Modeling of structural effects in biomedical elements after titanium oxidation in fluidized bed

    Science.gov (United States)

    Jasiński, J.; Szota, M.; Mendzik, K.

    2010-06-01

    Oxidation is one of the most employed methods to improve titanium and its alloys properties especially due to medical application. This process like most of the thermochemical treatment processes substantially influences on the characteristic of surface layers and the same on its mechanical and useful properties. Oxide coatings produced during titanium oxidation were examined due to their composition identification. Titanium was oxidized in fluidized bed in temperature range between 500÷700°C. Microstructures of titanium with a visible oxide coating on its surface after thermochemical treatment and changes of grain size in core of titanium samples are described. Moreover Xray phase analysis of obtained oxides coatings was made as well as microhardness measurements of titanium surface layers after oxidation process. Finally, the surfaces of titanium after oxidation in fluidized bed were measured by Auger electron spectroscopy. All research results are used to built numerical model of oxidation process in fluidized. Titanium oxidation process in fluidized bed is very complicated, because changes of parameters are non linear characteristics. This fact and lack of mathematical algorithms describing this process makes modeling properties of titanium elements by traditional numerical methods difficult or even impossible. In this case it is possible to try using artificial neural network. Using neural networks for modeling oxidizing in fluidized bed is caused by several nets' features: non linear character, ability to generalize the results of calculations for data out of training set, no need for mathematical algorithms describing influence changes input parameters on modeling materials properties.

  19. Effects of polyacrylamide on soil erosion and nutrient losses from substrate material in steep rocky slope stabilization projects.

    Science.gov (United States)

    Chen, Zhang; Chen, Wenlu; Li, Chengjun; Pu, Yanpin; Sun, Haifeng

    2016-06-01

    Erosion of denuded steep rocky slopes causes increasing losses of nitrogen and phosphorus, which is a severe problem in rocky slope protection. Thus, it is important to determine the appropriate materials that can reduce the erodibility and losses of nitrogen and phosphorus of the soil. In this paper, twenty-seven simulated rainfall events were carried out in a greenhouse, in which the substrate material was artificial soil; nine types of anionic polyacrylamide (PAM) were studied, which consisted of three molecular weight (6, 12, and 18 Mg mol(-1)) and three charge density (10, 20, and 30%) formulations in a 3 by 3 factorial design. The results showed that: (1) Polyacrylamide application reduced total nitrogen losses by 35.3% to 50.0% and total phosphorus losses by 34.9% to 48.0% relative to the control group. (2) The losses of total nitrogen and total phosphorus had significant correlation with the molecular weight. Besides, the losses of total phosphorus, particulate-bound phosphorus and inorganic nitrogen (NH4-N) were significantly correlated with their molecular weight and charge density. However, the losses of dissolved organic nitrogen, inorganic nitrogen (NO3-N), dissolved organic phosphorus, inorganic phosphorus (PO4-P) were non-significantly correlated with molecular weight and charge density. (3) Particulate-bound nitrogen and phosphorus were responsible for the losses of nitrogen and phosphorus during runoff events, where particulate-bound nitrogen made up 71.7% to 73.2% of total nitrogen losses, and particulate-bound phosphorus made up 82.3% to 85.2% of total phosphorus losses. (4) Polyacrylamide treatments increased water-stable aggregates content by 32.3% to 59.1%, total porosity by 11.3% to 49.0%, final infiltrative rate by 41.3% to 72.5%, and reduced soil erosion by 18.9% to 39.8% compared with the control group. Overall, the results of this study indicated that polyacrylamide application in the steep rocky slope stabilization projects could

  20. THREE-DIMENSIONAL SIMULATION FOR EFFECTS OF BED DISCORDANCE ON FLOW DYNAMICS AT Y-SHAPED OPEN CHANNEL CONFLUENCES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Channel confluences are universally present in nature. They can be divided into two types: asymmetrical river confluences and symmetric river confluences. The latter is also called as the Y-shaped confluences. Most of previous work has paid more attention to the asymmetrical river confluences, but few studies have been conducted on the Y-shaped confluences. In this article, the effects of bed discordance on the flow patterns at "Y" shaped open-channel confluences were studied by using a 3-D numerical simulation. It is proved that the model can undertake quantitative assessment of the flow at confluences. The results indicate that there are a lot of differences between the Y-shaped confluence and asymmetrical confluence. The discordant bed height plays an important role at the Y-shaped junction.

  1. EFFECTS OF NUTRIENT ENRICHMENT ON PRIMARY PRODUCTION AND BIOMASS OF SEDIMENT MICROALGAE IN A SUBTROPICAL SEAGRASS BED(1).

    Science.gov (United States)

    Bucolo, Philip; Sullivan, Michael J; Zimba, Paul V

    2008-08-01

    Eutrophication of coastal waters often leads to excessive growth of microalgal epiphytes attached to seagrass leaves; however, the effect of increased nutrient levels on sediment microalgae has not been studied within seagrass communities. A slow-release NPK Osmocote fertilizer was added to sediments within and outside beds of the shoal grass Halodule wrightii, in Big Lagoon, Perdido Key, Florida. Gross primary production (GPP) and biomass (HPLC photopigments) of sediment microalgae within and adjacent to fertilized and control H. wrightii beds were measured following two 4-week enrichment periods during June and July 2004. There was no effect of position on sediment microalgal GPP or biomass in control and enriched plots. However, nutrient enrichment significantly increased GPP in both June and July. These results suggest that sediment microalgae could fill some of the void in primary production where seagrass beds disappear due to excessive nutrient enrichment. Sedimentary chl a (proxy of total microalgal biomass) significantly increased only during the June enrichment period, whereas fucoxanthin (proxy of total diatom biomass) was not increased by nutrient enrichment even though its concentration doubled in the enriched plots in June. PMID:27041604

  2. Co-firing of Thai lignite and municipal solid waste (MSW) in a fluidised bed: Effect of MSW moisture content

    Energy Technology Data Exchange (ETDEWEB)

    Suksankraisorn, K.; Patumsawad, S.; Fungtammasan, B. [KMUTNB, Bangkok (Thailand). Dept. of Mechanical Engineering

    2010-12-15

    Co-firing investigation of a high-moisture-content municipal solid waste (MSW) with Thai lignite have been performed in a laboratory-scale fluidised bed to study the effects of MSW moisture content on the combustion and emission characteristics of major gaseous pollutants. In this study the comparison of 35%- and 60%-moisture MSWs were tested. The results show that the bed temperature in the case of 35%-moisture content is higher than for in case of 60%-moisture content due to the difference of physical properties of the fuel. The combustion efficiency for the case of 35%-moisture MSW is higher than that for 60%-moisture MSW due to higher bed temperature at lower waste moisture content. The synergistic effect of the co-firing of lignite with MSW reduces the emission of CO leading to increase in combustion efficiency. CO concentration for the case of 35%-moisture content is generally lower, and is much less sensitive to the level of excess air. Both the concentration values of SO{sub 2} and the fuel-S converted are lower for lower moisture content waste, particularly at high mass fraction of waste. The fuel mixture with low-moisture in waste gives higher fuel-N conversion to NO whereas the fuel-N conversion to N2O is higher for higher moisture content waste, particularly at high excess air.

  3. Biological aspects and ecological effects of a bed of the invasive non-indigenous mussel Brachidontes pharaonis (Fischer P., 1870 in Malta

    Directory of Open Access Journals (Sweden)

    L. BONNICI

    2012-12-01

    Full Text Available No mussel beds were known to occur in the Maltese Islands previous to 2009, when a single bed of the Lessepsian immigrant Brachidontes pharaonis, first recorded from the islands in 1970, was discovered in Birzebbugia Bay. The population structure of B. pharaonis was investigated to assess its potential to spread and colonise new shores, while the biotic community at the mussel bed was compared to that present on uncolonised substratum to determine the effects of mussel bed establishment on the associated biota. Results indicate a lower species richness and slightly different community structure with greater small-scale heterogeneity at the mussel bed site compared to the adjacent rocky shore where mussels are present but where there is no bed formation. The B. pharaonis population had a peak density of 16550 ± 2051 ind.m-2 within the mussel bed and included recent recruits. These data suggest that the B. pharaonis population has the potential to expand. Establishment of extensive beds by this invasive mussel could change the structure of native rocky shore assemblages around the Maltese Islands and elsewhere in the Mediterranean.

  4. Effects of erosion in the fate of soil organic carbon and soil aggregation in a burned Mediterranean hill-slope

    Science.gov (United States)

    Campo, Julian; Cammeraat, Erik; Gimeno-García, Eugenia; Andreu, Vicente

    2016-04-01

    The Intergovernmental Panel on Climate Change indicated a higher degree of confidence that meteorological conditions associated to climate change will be propitious to increasing extreme events manifested, among others, in bigger and more frequent wildfires (IPCC, 2014). Wildfires contribute to shaping the landscape, and also the geomorphological and hydrological processes that operate on soil are affected (Bento-Gonçalves et al., 2012). Whereas, it is well documented that wildfires produce significant changes on erosion processes, the associated fate of soil organic carbon (SOC) has received less attention. This research assesses this gap by studying the loss, redistribution, and stabilization of SOC in a Mediterranean forest hill-slope burned the 28-08-2014, with high severity fire, at the Natural Park of Sierra de Espadán, Spain (39°50'45.11"N, 0°22'20.52"W). To this end, soil was sampled (19-9-2014) in the foot's slope (depositional), middle part (transport) and top (eroding) at two depths (collected from four sediment fences constructed at the foot's slope, and together with soil samples, analysed with regard to SOC content and aggregate stability (AS). The main objective is to increase the understanding on the fate of SOC in Mediterranean burned areas experiencing soil erosion, transport and deposition, with special attention to the role of aggregation and disaggregation in redistribution processes. Immediately after the fire, SOC content was high (≈50 gC kg-1) as well as the AS (water drop test>146 drops). Significant differences (ANOVA, pBS) and soil depths (topsoil>subsoil). However, no significant differences were observed among eroding (58.8+20.8 gC kg-1), transport (67.3+34.4 gC kg-1), and depositional zones (62.0+31.3 gC kg-1), which is not in agreement with other SOC redistribution studies (Wang et al., 2014). Significant differences (Kruskal-Wallis, pBS) but not between soil depths or hill-slope positions. In the first post-fire erosive rains

  5. Effects of 14 days of head-down tilt bed rest on cutaneous vasoconstrictor responses in humans

    Science.gov (United States)

    Wilson, Thad E.; Shibasaki, Manabu; Cui, Jian; Levine, Benjamin D.; Crandall, Craig G.

    2003-01-01

    This study tested the hypothesis that head-down tilt bed rest (HDBR) reduces adrenergic and nonadrenergic cutaneous vasoconstrictor responsiveness. Additionally, an exercise countermeasure group was included to identify whether exercise during bed rest might counteract any vasoconstrictor deficits that arose during HDBR. Twenty-two subjects underwent 14 days of strict 6 degrees HDBR. Eight of these 22 subjects did not exercise during HDBR, while 14 of these subjects exercised on a supine cycle ergometer for 90 min a day at 75% of pre-bed rest heart rate maximum. To assess alpha-adrenergic vasoconstrictor responsiveness, intradermal microdialysis was used to locally administer norepinephrine (NE), while forearm skin blood flow (SkBF; laser-Doppler flowmetry) was monitored over microdialysis membranes. Nonlinear regression modeling was used to identify the effective drug concentration that caused 50% of the cutaneous vasoconstrictor response (EC(50)) and minimum values from the SkBF-NE dose-response curves. In addition, the effects of HDBR on nonadrenergic cutaneous vasoconstriction were assessed via the venoarteriolar response of the forearm and leg. HDBR did not alter EC(50) or the magnitude of cutaneous vasoconstriction to exogenous NE administration regardless of whether the subjects exercised during HDBR. Moreover, HDBR did not alter the forearm venoarteriolar response in either the control or exercise groups during HDBR. However, HDBR significantly reduced the magnitude of cutaneous vasoconstriction due to the venoarteriolar response in the leg, and this response was similarly reduced in the exercise group. These data suggest that HDBR does not alter cutaneous vasoconstrictor responses to exogenous NE administration, whereas cutaneous vasoconstriction of the leg due to the venoarteriolar response is reduced after HDBR. It remains unclear whether attenuated venoarteriolar responses in the lower limbs contribute to reduced orthostatic tolerance after bed rest and

  6. Effects of electrode geometry on the performance of dielectric barrier/packed-bed discharge plasmas in benzene degradation

    International Nuclear Information System (INIS)

    Highlights: • Benzene was successfully degraded by dielectric barrier/packed-bed discharge plasmas. • Different electrode geometry has distinct effect on plasmas oxidation performance. • Benzene degradation and energy performance were enhanced when using the coil electrode. • The reaction products were well determined by online FTIR analysis. -- Abstract: In this study, the effects of electrode geometry on benzene degradation in a dielectric barrier/packed-bed discharge plasma reactor with different electrodes were systematically investigated. Three electrodes were employed in the experiments, these were coil, bolt, and rod geometries. The reactor using the coil electrode showed better performance in reducing the dielectric loss in the barrier compared to that using the bolt or rod electrodes. In the case of the coil electrode, both the benzene degradation efficiency and energy yield were higher than those for the other electrodes, which can be attributed to the increased role of surface mediated reactions. Irrespective of the electrode geometry, the packed-bed discharge plasma was superior to the dielectric barrier discharge plasma in benzene degradation at any specific applied voltage. The main gaseous products of benzene degradation were CO, CO2, H2O, and formic acid. Discharge products such as O3, N2O, N2O5, and HNO3 were also detected in the outlet gas. Moreover, the presence of benzene inhibited the formation of ozone because of the competing reaction of oxygen atoms with benzene. This study is expected to offer an optimized approach combining dielectric barrier discharge and packed-bed discharge to improve the degradation of gaseous pollutants

  7. Determination of the effective thermal diffusivity in a porous bed containing rice grains: effects of moisture content and temperature

    Science.gov (United States)

    Dotto, G. L.; Pinto, L. A. A.; Moreira, M. F. P.

    2016-04-01

    The effective thermal diffusivity ( α ef ) of a porous bed containing rice grains was determined under different experimental conditions. The α ef values were estimated by the Log method. The effects of rice moisture content (2, 12 and 22 % w.b.) and temperature (15, 35, 55 and 75 °C) on the α ef values were investigated. Finally, an empirical model was proposed to represent the effective thermal diffusivity as a function of the moisture content ( X) and temperature ( T). The results revealed that the increase in the rice moisture content and temperature caused an increase in α ef values, which ranged from 0.91 × 10-7 to 3.23 × 10-7 m2 s-1. In the studied range, the dependence of α ef with the rice moisture content and temperature can be represented as: α ef (m2s-1) = (0.63 + 5.63 × 10-2 X + 1.51 × 10-2 T + 1.17 × 10-4 XT) × 10-7. The proposed empirical model was suitable to predict the α ef values with mean absolute percentage deviation of 3.8 % and is a tool for future modeling purposes.

  8. Bed rest and immunity

    Science.gov (United States)

    Sonnenfeld, Gerald; Aviles, Hernan; Butel, Janet S.; Shearer, William T.; Niesel, David; Pandya, Utpal; Allen, Christopher; Ochs, Hans D.; Blancher, Antoine; Abbal, Michel

    2007-02-01

    Space flight has been shown to result in altered immune responses. The current study was designed to investigate this possibility by using the bed rest model of some space flight conditions. A large number of women are included as subjects in the study. The hypothesis being tested is: 60 days head-down tilt bed rest of humans will affect the immune system and resistance to infection. Blood, urine and saliva samples will be obtained from bed rest subjects prior to, at intervals during, and after completion of 60 days of head-down tilt bed rest. Leukocyte blastogenesis, cytokine production and virus reactivation will be assessed. The ability of the subjects to respond appropriately to immunization with the neoantigen bacteriophage φX-174 will also be determined. Bed rest is being carried out at MEDES, Toulouse France, and the University of Texas Medical Branch, Galveston, TX. The studies to be carried out in France will also allow assessment of the effects of muscle/bone exercise and nutritional countermeasures on the immune system in addition to the effects of bed rest.

  9. Effect of air preheating and fuel moisture on combustion characteristics of corn straw in a fixed bed

    International Nuclear Information System (INIS)

    Experiments were carried out on a one-dimensional bench combustion tests rig. The effect of air preheating and moisture level in the fuel on combustion characteristics of corn straw was investigated. The bed temperature distribution and the mass loss of fuel and gas components such as O2, CO, CO2 and NO were measured in the bed. The average burning rate and ignition front propagation velocity increased with increasing primary air preheating temperature. The total burning time was shorter under the higher primary air preheating temperature and the higher primary air preheating temperature produced a lower ignition front flame temperature in the bed. The variation of the flue gas O2, CO and CO2 concentrations with time was more intensive at a higher primary air preheating temperature during the ignition front propagation period and the char oxidation period. With the increase of the fuel moisture, average burning rate and ignition front propagation velocity decreased. As the fuel moisture was less than 30.71%, with the increase of the fuel moisture, residual mass loss rate decreased and ignition front flame temperature increased at a fixed air flow rate. Drier fuels resulted in fuel-rich combustion and higher CO concentration. The NO concentration decreased with increasing the moisture level in the fuel

  10. Enteric coating of soft gelatin capsules by spouted bed: effect of operating conditions on coating efficiency and on product quality.

    Science.gov (United States)

    Pissinati, Rafael; Oliveira, Wanderley Pereira

    2003-05-01

    The present study was conducted in order to analyze the viability of the spouted bed process for application of a gastric-resistant coating to soft gelatin capsules. The variables investigated were: included angle of conical base, (gamma), the relation between the feed mass flow rate of the coating suspension and the feed mass flow rate of spouting gas (W(s)/W(g)); the ratio between the flow rate of the spouting gas and the flow rate at minimum spouting condition (Q/Q(ms)); the mass of capsules in the bed (M(0)), and the capsule's size. The product quality was measured by disintegration tests, traction x deformation tests, image analysis and by the evaluation of the coating mass distribution and shape factor variation during the coating operation. The experiments were performed in a spouted bed with a column diameter of 200 mm and included a conical base angle of 40 degrees. The best coating efficiency values were obtained for M(0)=300 g. Coating efficiency tended to increase with increasing W(s)/W(g) ratio. Disintegration tests showed that the gastric-resistant effect was obtained with a coating mass of 3.86 mg/cm(2). The shape factor increase during the coating operation. The capsule's coating mass distribution tended to maintain the original distribution. PMID:12754006

  11. New evidence for enhanced preservation of organic carbon in contact with oxygen minimum zone on the western continental slope of India

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A.L.; PrakashBabu, C.; Mascarenhas, A.

    . 306) and higher organic carbon contents (av. 3.28 wt.%) with the sediments of the upper slope in contact with the OMZ have excellent hydrocarbon generation potential, and that these slope beds deserve preferential attention for hydrocarbon exploration...

  12. Fluid bed drying of guarana (Paullinia cupana HBK) extract: Effect of process factors on caffeine content

    OpenAIRE

    Pagliarussi, Renata S.; Bastos, Jairo K.; Luis A. P. Freitas

    2006-01-01

    The aim of this study was to study the convective drying of the hydroalcoholic extracts obtained from powdered guarana seeds in a spouted bed dryer. The influence of process variables, such as the convective airflow rate, extract feed rate, and air inlet temperature, on the quality of the dry extract was determined using the caffeine and moisture content for the process evaluation. The caffeine content in the alcoholic and dried extracts was determined by capillary gas chromatography. The exp...

  13. Effects of Starvation on Deltamethrin Tolerance in Bed Bugs, Cimex lectularius L. (Hemiptera: Cimicidae

    Directory of Open Access Journals (Sweden)

    Zachary C. DeVries

    2015-01-01

    Full Text Available Bed bugs, Cimex lectularius L., are a major pest in the urban environment. Their presence often results in physical, psychological, and financial distress of homeowners and apartment dwellers. Although many insecticide bioassays have been performed on this pest, little attention has been paid to bed bug feeding status, which is closely linked to metabolism, molting, and mass. Therefore, we evaluated the toxicity of topically applied deltamethrin on insecticide susceptible adult male bed bugs fed 2 d, 9 d, and 21 d prior to testing. When toxicity was evaluated on a “per-bug” basis, there was no difference between 2 d [LD50 = 0.498 (0.316 − 0.692 ng·bug−1] and 9 d [LD50 = 0.572 (0.436 − 0.724 ng·bug−1] starved bugs, while 21 d starved bugs had a significantly lower LD50 [0.221 (0.075 − 0.386 ng·bug−1]. When toxicity was evaluated in terms of body mass, 9 d starved bugs had the highest LD50 values [0.138 (0.102 − 0.176 ng·mg−1], followed by 2 d starved bugs [0.095 (0.060 − 0.134 ng·mg−1], and then 21 d starved bugs [0.058 (0.019–0.102 ng·mg−1]; the LD50 values of 2 d and 9 d starved bugs were significantly different from 21 d starved bugs. These results indicate that feeding status plays an important role in the toxicity of deltamethrin. In addition, the lack of differences between 2 d and 9 d starved bugs indicate that the blood meal itself has little impact on tolerance, but rather it is some physiological change following feeding that confers increased tolerance to bed bugs.

  14. Effects of the gas flow through the granular solid fuel bed

    Energy Technology Data Exchange (ETDEWEB)

    Postrzednik, S.; Tiamiyu, K.M.; Zmudka, Z. [Technical University of Silesia, Gliwice (Poland). Inst. of Thermal Technology

    1995-12-31

    Generalized concepts and procedures for the determination of the flow characteristics in granular solid fuel bed are presented. An analytical framework which enables the identification of the basic parameters affecting the intensity of low temperature oxidation and weathering of heaped-up systems (such as stockpiles) were formulated. The concepts and solution procedures were applied to study the flow characteristics of some Polish coal grades. 3 refs., 3 figs.

  15. Comparative analysis of CFD models for jetting fluidized beds: Effect of particle-phase viscosity

    Institute of Scientific and Technical Information of China (English)

    Pei Pei; Kai Zhang; Gang Xu; Yongping Yang; Dongsheng Wen

    2012-01-01

    Under the Eulerian-Eulerian framework of simulating gas-solid two-phase flow,the accuracy of the hydrodynamic prediction is strongly affected by the selection of rheology of the particulate phase,for which a detailed assessment is still absent.Using a jetting fluidized bed as an example,this work investigates the influence of solid theology on the hydrodynamic behavior by employing different particle-phase viscosity models.Both constant particle-phase viscosity model (CVM) with different viscosity values and a simple two-fluid model without particle-phase viscosity (NVM) are incorporated into the classical twofluid model and compared with the experimental measurements.Qualitative and quantitative results show that the jet penetration depth,jet frequency and averaged bed pressure drop are not a strong function of the particle-phase viscosity.Compared to CVM,the NVM exhibits better predictions on the jet behaviors,which is more suitable for investigating the hydrodynamics of gas-solid fluidized bed with a central jet.

  16. Effects of draft tubes on particle velocity profiles in spouted beds

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, X.L.; Yao, Q.; Li, S.Q. [Department of Thermal Engineering, Tsinghua University, Beijing (China)

    2006-07-15

    The vertical particle velocity profiles in a full-column cylindrical conical spouted bed, with or without a draft tube, are measured using a fibre optic probe system. The profiles have different characteristics for a draft tube spouted bed (DTSB) than for a conventional spouted bed (CSB). The spout of a CSB consists of a central flow where particle velocities fit exponential distributions, and a boundary layer where particle velocities are nearly uniform. The spout of a DTSB has no boundary layer and its radial particle velocity profiles are approximately linear. The particle velocities in the spout of a DTSB increase when superficial gas velocity increases, draft tube diameter decreases, or when entrainment height decreases. A kinematic model has been used to simulate the granular flow in the annulus of a CSB and DTSB, and they are compared with the experiments. The particle velocities in the annulus of a DTSB are much lower than that of a CSB. Their radial profiles are also different with a CSB. The dependence of particle velocities in the annulus of a DTSB on superficial gas velocity, draft tube diameter, and entrainment height are also discussed. One concludes that the draft tube diameter and entrainment height are two key factors for the solid circulation rate of a DTSB. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  17. Fluid bed drying of guarana (Paullinia cupana HBK) extract: effect of process factors on caffeine content.

    Science.gov (United States)

    Pagliarussi, Renata S; Bastos, Jairo K; Freitas, Luis A P

    2006-01-01

    The aim of this study was to study the convective drying of the hydroalcoholic extracts obtained from powdered guarana seeds in a spouted bed dryer. The influence of process variables, such as the convective airflow rate, extract feed rate, and air inlet temperature, on the quality of the dry extract was determined using the caffeine and moisture content for the process evaluation. The caffeine content in the alcoholic and dried extracts was determined by capillary gas chromatography. The experiments were performed following a 3(3) factorial design and the data analyzed by response surface. The analysis of dry extract showed that the air and extract feed rates did not significantly affect (25% level) the caffeine content, but that drying temperature is a major factor to consider when the extract is submitted to fluid bed drying. Caffeine losses were significant (1% level) for drying temperatures above 120 degrees C, while moisture content was lower than 3% for temperatures above 120 degrees C. The data showed that there is an optimum temperature for the drying of guarana extracts in spouted beds, and under the conditions used in this study it was 120 degrees C. PMID:16796371

  18. Simulation of carbon dioxide absorption by sodium hydroxide solution in a packed bed and studying the effect of operating parameters on absorption

    International Nuclear Information System (INIS)

    Available in abstract form only. Full text of publication follows: In this study. simulation of carbon dioxide absorption by Sodium Hydroxide solution in a packed bed has been investigated. At first, mass and energy balances were applied around a differential height of the bed. So, the governing equations were obtained. Surface renewal theory by Danckwerts was used to represent the mass transfer operation Finally, by changing the operating parameters like solvent temperature, inlet gas composition pressure and height of the bed, the effect of these parameters on the absorption and the composition of carbon dioxide in exit stream have been investigated. (authors)

  19. The sloping land conversion program in China

    DEFF Research Database (Denmark)

    Liu, Zhen; Lan, Jing

    2015-01-01

    Through addressing the motivations behind rural households’ livelihood diversification, this paper examines the effect of the Sloping Land Conversion Program (SLCP) on livelihood diversification using a longitudinal household survey data set spanning the overall implementation of the SLCP. Our...

  20. A graphical user interface (GUI) toolkit for the calculation of three-dimensional (3D) multi-phase biological effective dose (BED) distributions including statistical analyses.

    Science.gov (United States)

    Kauweloa, Kevin I; Gutierrez, Alonso N; Stathakis, Sotirios; Papanikolaou, Niko; Mavroidis, Panayiotis

    2016-07-01

    A toolkit has been developed for calculating the 3-dimensional biological effective dose (BED) distributions in multi-phase, external beam radiotherapy treatments such as those applied in liver stereotactic body radiation therapy (SBRT) and in multi-prescription treatments. This toolkit also provides a wide range of statistical results related to dose and BED distributions. MATLAB 2010a, version 7.10 was used to create this GUI toolkit. The input data consist of the dose distribution matrices, organ contour coordinates, and treatment planning parameters from the treatment planning system (TPS). The toolkit has the capability of calculating the multi-phase BED distributions using different formulas (denoted as true and approximate). Following the calculations of the BED distributions, the dose and BED distributions can be viewed in different projections (e.g. coronal, sagittal and transverse). The different elements of this toolkit are presented and the important steps for the execution of its calculations are illustrated. The toolkit is applied on brain, head & neck and prostate cancer patients, who received primary and boost phases in order to demonstrate its capability in calculating BED distributions, as well as measuring the inaccuracy and imprecision of the approximate BED distributions. Finally, the clinical situations in which the use of the present toolkit would have a significant clinical impact are indicated. PMID:27265044

  1. Effect of temperature and dolomite on tar formation during gasification of torrefied biomass in a pressurized fluidized bed

    International Nuclear Information System (INIS)

    This work investigates the effect of temperature and bed material on the yields and composition of gas and tar produced from gasification of two types of biomass feedstock previously torrefied at 275 °C. Special attention was devoted to the evolution of tar composition under the different experimental conditions. Experiments were conducted in a fluidized bed reactor using two different types of bed material (sand and dolomite) under a constant pressure of 0.5 MPa and at two temperature levels (750 and 850 °C). Tar destruction reactions promoted by the catalyst (dolomite) enhanced the production of some of the gas components (H2, CO2, CO and CH4) whereas C2 hydrocarbons decreased, this effect being slightly more relevant at 850 °C. Comparable trends were observed with increasing temperature, which had a positive effect on cracking reactions and tar destruction. For both feedstocks, the increase in temperature resulted in (i) higher gas yields, and (ii) enhanced char gasification rate. On the other hand the evolution of tar yield and composition revealed a possible competition between two tar reaction pathways during gasification, (i) tar polymerization, and (ii) de-alkylation, dehydration and cracking of tars, depending on the experimental conditions and feedstock used. - Highlights: • An experimental study of pressurized gasification of torrefied biomass is presented. • Special attention was devoted to the evolution of tar composition. • Increasing temperature and dolomite presence led to higher gas and lower tar yields. • Tar evolution revealed a possible competition between two tar reaction pathways

  2. Effect of a Reactivation strategy based on partial bio catalyst replacement on the performance of a fungal fluidized bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Ortega-Clemente, A.; Robledo-Narvaez, P.; Barrera-Cortes, J.; Poggi-Varaldo, H. M.

    2009-07-01

    The Mexican pulp and paper industry discharges approximately 12% of the annual industrial discharges and holds a second position in the ranking of main water industrial polluters in Mexico. Their wastewaters are characteristically recalcitrant and toxic. The objective of this work was to evaluate the effectiveness of two operational strategies on the performance of two fungal fluidized bed reactor (FBR) for the post-treatment of anaerobically weal black liquor systems (AP-WBL) without supplementation of soluble carbohydrates, i. e. Strategy 1 (continuous operation with the same original, fungal bio catalysts and eventual spikes of protease inhibitor and glucose), and Strategy 2 operation with partial exchange of bio catalysts. (Author)

  3. Effect of Contact Resistance on Bulk Resistivity of Dry Coke Beds

    Science.gov (United States)

    Eidem, P. A.; Runde, M.; Tangstad, M.; Bakken, J. A.; Zhou, Z. Y.; Yu, A. B.

    2009-06-01

    Measurements show that bulk resistivity of dry coke beds decreases with increasing particle size. A further development of a coke bed model is proposed to explain this correlation. By image analysis, it has been determined that the total porosity increases with increasing particle size. An increased total porosity of the particles decreases the mechanical strength of the particles. In the modeling work, the strength of the coke particles is introduced through Young’s modulus. By the use of discrete element method (DEM) modeling of a dry coke bed, the particle-to-particle contact area variation with varying particle size and particle strength has been introduced into a model of the dry coke bed. This was done by the introduction of the concept of the Holm’s radius, known from metal contact theory for describing how the contact resistance is affected by the material resistivity and the contact area. By assuming a decrease in the particle strength due to increased porosity of the coke particles with increasing particle size, the calculated bulk resistivity for 7.3-mm particles with a Young’s modulus of 1.0 GPa is 5.24·10-3 Ωm and 3.44·10-3 Ωm for the 20-mm particles with a Young’s modulus of 0.1 GPa. By comparison, the measured bulk resistivity of the Corus coke is 4.67 ± 0.30·10-3 Ωm for the 5- to 10-mm fraction and 3.71 ± 0.45·10-3 Ωm for the 15- to 20-mm fraction. The measured contact resistance of Swedish Steel AB (SSAB) coke decreases with increasing contact area size from a contact diameter of 5 mm to a contact diameter of 30 mm. This is probably due to an increasing number of electrical contact spots. When two spheres are in contact, the measured contact resistance is lower compared to the 5-mm-diameter contact, which indicates that the increased contact pressure has lowered the contact resistance. This supports the modeling results.

  4. 岩质边坡爆破振动速度的高程放大效应研究%ELEVATION AMPLIFICATION EFFECT OF BLASTING VIBRATION VELOCITY IN ROCK SLOPE

    Institute of Scientific and Technical Information of China (English)

    陈明; 卢文波; 李鹏; 刘美山; 周创兵; 赵根

    2011-01-01

    岩质边坡爆破振动的高程放大效应是边坡上振动速度传播规律的重要研究内容之一.基于岩质边坡爆破振动高程响应机制的理论分析以及边坡开挖爆破振动的数值模拟与实例分析,研究边坡爆破振动速度的高程放大效应.结果表明,边坡爆破振动速度的高程放大效应是在一定的条件下产生的,受爆破振动荷载特性及边坡坡形等因素的影响.爆破振动荷载作用下,边坡坡面不同高程台阶岩体结构的自振主频率处于爆破振动荷载主频带范围内,台阶部位岩体结构的振动响应会产生"鞭梢效应",导致台阶部位岩体振动速度放大.在边坡坡形骤变、坡度增大时,边坡上一级台阶岩体的振动速度可大于下一级台阶岩体的振动速度,产生显著的振动速度高程放大效应.坡形相近的条件下,台阶坡脚处的振动速度随高程的增加逐渐减小,不出现振动速度高程放大效应."鞭梢效应"影响下,边坡台阶边沿的振动速度较大,但应力、应变较同高程台阶坡脚处的小,边沿部位的振动速度不适宜评价边坡的稳定性.%Elevation amplification effect of blasting vibration is an important study content of vibration propagation law on rock slope. Based on the theoretical analysis of elevation response mechanism on rock slope, numerical simulation of blasting vibration induced by slope excavation and measured data analysis, the blasting vibration elevation amplification effect has been studied. The results indicate that the blasting vibration elevation amplification effect occurs under some conditions and it is affected by factors such as the property of blasting vibration and the slope form. Under the blasting load, when the natural frequencies of different slope benches correspond with the main frequency band of blast load, the"whiplash effects" are caused in rock structures of the slope benches and the vibrations are amplified. While slope form

  5. Effects of Cage Density, Sanitation Frequency, and Bedding Type on Animal Wellbeing and Health and Cage Environment in Mice and Rats

    OpenAIRE

    Horn, Mandy J; Hudson, Shanice V.; Bostrom, Linda A; Cooper, Dale M

    2012-01-01

    The objective of the current study was to evaluate the effects of cage density, sanitation frequency, and bedding type on animal growth and welfare. At weaning, Sprague–Dawley rats and C57BL/6 mice were allocated to treatment groups according to sex, bedding type (shredded aspen, cellulose, or a 50:50 mixture), and cage density and sanitation frequency (inhouse cage density standards and sanitation procedures measured against Guide recommendations) for an 8-wk period. Body weight, feed disapp...

  6. Effect of HRT on nitrogen removal in a coupled HRP and unplanted subsurface flow gravel bed constructed wetland

    Science.gov (United States)

    Mayo, A. W.; Mutamba, J.

    This paper discusses the effect of hydraulic retention time (HRT) on nitrogen removal in a coupled high rate pond (HRP) and a gravel bed subsurface constructed wetland (SSCW) wastewater treatment plant. A pilot plant consisting of a high rate pond (HRT) coupled to an unplanted gravel bed subsurface constructed wetland (SSCW) was used to investigate nitrogen removal from domestic wastewater at the University of Dar es Salaam. The influent, which is predominantly of domestic origin, was drawn from the facultative pond unit of the university’s waste stabilisation pond system. The pilot plant’s HRP unit, which was 0.6 m deep, was designed to nitrify the influent while SSCW unit, which was filled to 10 cm above water level with 19-mm diameter aggregates, was predominantly anoxic and promoted denitrification. The study was conducted at two different operational settings. In Phase 1, both the HRP and the SSCW units had a retention time of 5 days. During Phase 2, the hydraulic retention time in HRP was increased to 8 days while the retention time of the SSCW unit was maintained at 5 days. Samples were collected daily for laboratory analysis of influent and effluent wastewater quality. All experiments were conducted in accordance with Standard Methods. The results showed that improved nitrogen removal occurred with increase in hydraulic time of the HRP unit. In Phase 1 an average nitrogen removal of 33% was achieved while removal efficiency improved to 43% in Phase 2. It was also revealed that the HRP can effectively be used to promote nitrification and the unplanted gravel bed subsurface constructed wetland can be used as a denitrifying unit.

  7. The Effect of Bed Rest on Bone Turnover in Young Women Hospitalized for Anorexia Nervosa: A Pilot Study

    Science.gov (United States)

    DiVasta, Amy D.; Feldman, Henry A.; Quach, Ashley E.; Balestrino, Maria; Gordon, Catherine M.

    2009-01-01

    Context: Malnourished adolescents with anorexia nervosa (AN) requiring medical hospitalization are at high risk for skeletal insults. Even short-term bed rest may further disrupt normal patterns of bone turnover. Objective: The objective of the study was to determine the effect of relative immobilization on bone turnover in adolescents hospitalized for AN. Design: This was a short-term observational study. Setting: The study was conducted at a tertiary care pediatric hospital. Study Participants: Twenty-eight adolescents with AN, aged 13–21 yr with a mean body mass index of 15.9 ± 1.8 kg/m2, were enrolled prospectively on admission. Intervention: As per standard care, all subjects were placed on bed rest and graded nutritional therapy. Main Outcome Measure: Markers of bone formation (bone specific alkaline phosphatase), turnover (osteocalcin), and bone resorption (urinary N-telopeptides NTx) were measured. Results: During the 5 d of hospitalization, serum osteocalcin increased by 0.24 ± 0.1 ng/ml · d (P = 0.02). Urine N-telopeptides reached a nadir on d 3, declining −6.9 ± 2.8 nm bone collagen equivalent per millimole creatinine (P = 0.01) but returned to baseline by d 5 (P > 0.05). Bone-specific alkaline phosphatase exhibited a decline that was strongly age dependent, being highly significant for younger subjects only [age 14 yr: −0.42 ± 0.11 (P = 0.0002); age 18 yr: −0.03 ± 0.08 (P = 0.68)]. Age had no effect on other outcome measures. Conclusion: Limitation of physical activity during hospitalization for patients with AN is associated with suppressed bone formation and resorption and an imbalance of bone turnover. Future interventional studies involving mechanical stimulation and/or weight-bearing activity are needed to determine whether medical protocols prescribing strict bed rest are appropriate. PMID:19223524

  8. Mechanical interaction between roots and soil mass in slope vegetation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The most basic function of slope vegetation is to strengthen rock and soil mass through plant roots which increase the shear strength of the slope markedly and thereby increase the stability of the slope. However, the calculation of the reinforcement ability of slope vegetation still remains at the stage of judging by experience, because it is rather difficult due to the intricacy and volatility of the force condition of plant roots in rock and soil medium. Although some scholars have tried to study the interaction between plant roots and soil mass, the systemic analysis of the mechanical reinforcement mechanism and the contribution of plant roots to strengthening the rock and soil mass on the surface of the slope is untapped. In this paper, by analyzing the mechanism of slope vegetation and the corresponding reinforcement effect, the effects that slope vegetation generates on the shear strength of slope soil mass are studied, thereby a theoretical basis for plant protection designing is provided.

  9. AN EFFECTIVE HYBRID SUPPORT VECTOR REGRESSION WITH CHAOS-EMBEDDED BIOGEOGRAPHY-BASED OPTIMIZATION STRATEGY FOR PREDICTION OF EARTHQUAKE-TRIGGERED SLOPE DEFORMATIONS

    Directory of Open Access Journals (Sweden)

    A. A. Heidari

    2015-12-01

    Full Text Available Earthquake can pose earth-shattering health hazards to the natural slops and land infrastructures. One of the chief consequences of the earthquakes can be land sliding, which is instigated by durable shaking. In this research, an efficient procedure is proposed to assist the prediction of earthquake-originated slope displacements (EIDS. New hybrid SVM-CBBO strategy is implemented to predict the EIDS. For this purpose, first, chaos paradigm is combined with initialization of BBO to enhance the diversification and intensification capacity of the conventional BBO optimizer. Then, chaotic BBO is developed as the searching scheme to investigate the best values of SVR parameters. In this paper, it will be confirmed that how the new computing approach is effective in prediction of EIDS. The outcomes affirm that the SVR-BBO strategy with chaos can be employed effectively as a predicting tool for evaluating the EIDS.

  10. An Effective Hybrid Support Vector Regression with Chaos-Embedded Biogeography-Based Optimization Strategy for Prediction of Earthquake-Triggered Slope Deformations

    Science.gov (United States)

    Heidari, A. A.; Mirvahabi, S. S.; Homayouni, S.

    2015-12-01

    Earthquake can pose earth-shattering health hazards to the natural slops and land infrastructures. One of the chief consequences of the earthquakes can be land sliding, which is instigated by durable shaking. In this research, an efficient procedure is proposed to assist the prediction of earthquake-originated slope displacements (EIDS). New hybrid SVM-CBBO strategy is implemented to predict the EIDS. For this purpose, first, chaos paradigm is combined with initialization of BBO to enhance the diversification and intensification capacity of the conventional BBO optimizer. Then, chaotic BBO is developed as the searching scheme to investigate the best values of SVR parameters. In this paper, it will be confirmed that how the new computing approach is effective in prediction of EIDS. The outcomes affirm that the SVR-BBO strategy with chaos can be employed effectively as a predicting tool for evaluating the EIDS.

  11. Effects of mass action equilibria on fixed-bed multicomponent ion-exchange dynamics

    International Nuclear Information System (INIS)

    A generalized parallel pore and surface diffusion model and associated dynamic simulation program have been developed for multicomponent fixed-bed ion-exchange processes. Both equilibrium and nonequilibrium mass action laws are used to describe stoichiometric ion exchange. Model equations are solved numerically for frontal, pulse, or sequential loading processes. Analytical solutions obtained from a local equilibrium theory for binary systems and experimental data of two multicomponent systems served as benchmarks for the numerical solutions. The results indicate that the parallel pore and surface diffusion model should be considered for nonlinear large-particle systems. A parametric study shows that a major difference in fixed-bed dynamics between mass action and Langmuir systems lies in the propagation of diffuse waves of multivalent ions. Generally, the higher the valence or mass action equilibrium constant, the more pronounced the tailing of diffuse waves, which results in apparent adsorption hysteresis in a loading and washing cycle. The apparently irreversibly adsorbed multivalent ions can be eluted by concentrated solutions of lower valence ions, as a result of the relative selectivities of the higher valence against lower valence ions decreasing with increasing total solution phase concentration. This can lead to changes from favorable to unfavorable isotherms and self-sharpening eaves to diffuse waves, or vice versa. Other results show that elution order can be reversed for heterovalent ions in elution and displacement chromatography

  12. The effects of muscle exercise and bed rest on [18F]methylcholine PET/CT

    International Nuclear Information System (INIS)

    This study evaluated the impact of limited and strenuous physical exercise on [18F]methylcholine uptake in muscle. Ten consecutive patients participated, three of whom had strict bed rest, three were allowed to walk around and four performed strenuous single arm exercise by lifting a 7.5-kg weight. [18F]Methylcholine uptake was measured in the biceps and gluteus muscles on both sides. Strenuous exercise resulted in a 202% increase in [18F]methylcholine uptake in the activated biceps muscle as well as a 112% increase in muscle groups used to retain body position. This resulted in asymmetrical images that were visually less easy to interpret. In walking patients there was a more limited increase in biceps (45%) and gluteus (74%) muscle uptake, without visually recognizable differences. Strenuous exercise may result in a considerable increase in [18F]methylcholine uptake in muscle and should be avoided prior to imaging. Strict bed rest does not seem to be required. Tracer injection while resting on the scanner remains a safe approach. (orig.)

  13. Effects of space allocation within a deep bedded finishing system on swine growth performance, fatty acid composition and pork quality

    Science.gov (United States)

    The objectives of the current study were to determine the degree to which space allocation in a deep-bedded system influences swine performance and pork quality. The deep-bedded method employed was hoop structures which are large, tent-like shelters with cornstalks or straw for bedding. One hundred ...

  14. Cost and cost effectiveness of long-lasting insecticide-treated bed nets - a model-based analysis

    Directory of Open Access Journals (Sweden)

    Pulkki-Brännström Anni-Maria

    2012-04-01

    Full Text Available Abstract Background The World Health Organization recommends that national malaria programmes universally distribute long-lasting insecticide-treated bed nets (LLINs. LLINs provide effective insecticide protection for at least three years while conventional nets must be retreated every 6-12 months. LLINs may also promise longer physical durability (lifespan, but at a higher unit price. No prospective data currently available is sufficient to calculate the comparative cost effectiveness of different net types. We thus constructed a model to explore the cost effectiveness of LLINs, asking how a longer lifespan affects the relative cost effectiveness of nets, and if, when and why LLINs might be preferred to conventional insecticide-treated nets. An innovation of our model is that we also considered the replenishment need i.e. loss of nets over time. Methods We modelled the choice of net over a 10-year period to facilitate the comparison of nets with different lifespan (and/or price and replenishment need over time. Our base case represents a large-scale programme which achieves high coverage and usage throughout the population by distributing either LLINs or conventional nets through existing health services, and retreats a large proportion of conventional nets regularly at low cost. We identified the determinants of bed net programme cost effectiveness and parameter values for usage rate, delivery and retreatment cost from the literature. One-way sensitivity analysis was conducted to explicitly compare the differential effect of changing parameters such as price, lifespan, usage and replenishment need. Results If conventional and long-lasting bed nets have the same physical lifespan (3 years, LLINs are more cost effective unless they are priced at more than USD 1.5 above the price of conventional nets. Because a longer lifespan brings delivery cost savings, each one year increase in lifespan can be accompanied by a USD 1 or more increase in price

  15. Drainage effects on the transient, near-surface hydrologic response of a steep hillslope to rainfall: implications for slope stability, Edmonds, Washington, USA

    Directory of Open Access Journals (Sweden)

    G. Biavati

    2006-01-01

    Full Text Available Shallow landslides on steep (>25° hillsides along Puget Sound have resulted in occasional loss of life and costly damage to property during intense or prolonged rainfall. As part of a larger project to assess landslide hazards in the Seattle area, the U.S. Geological Survey instrumented two coastal bluff sites in 2001 to observe the subsurface hydrologic response to rainfall. The instrumentation at one of these sites, near Edmonds, Washington, consists of two rain gauges, two water-content probes that measure volumetric water content at eight depths between 0.2 and 2.0 m, and two tensiometer nests that measure soil-water suction at six depths ranging from 0.2 to 1.5 m. Measurements from these instruments are used to test one- and two-dimensional numerical models of infiltration and groundwater flow. Capillary-rise tests, performed in the laboratory on soil sample from the Edmonds site, are used to define the soil hydraulic properties for the wetting process. The field observations of water content and suction show an apparent effect of porosity variation with depth on the hydraulic response to rainfall. Using a range of physical properties consistent with our laboratory and field measurements, we perform sensitivity analyses to investigate the effects of variation in physical and hydraulic properties of the soil on rainfall infiltration, pore-pressure response, and, hence, slope stability. For a two-layer-system in which the hydraulic conductivity of the upper layer is at least 10 times greater than the conductivity of the lower layer, and the infiltration rate is greater than the conductivity of the lower layer, a perched water table forms above the layer boundary potentially destabilizing the upper layer of soil. Two-dimensional modeling results indicate that the addition of a simple trench drain to the same two-layer slope has differing effects on the hydraulic response depending on the initial pressure head conditions. For slope

  16. Drainage effects on the transient, near-surface hydrologic response of a steep hillslope to rainfall: Implications for slope stability, Edmonds, Washington, USA

    Science.gov (United States)

    Biavati, G.; Godt, J.W.; McKenna, J.P.

    2006-01-01

    Shallow landslides on steep (>25??) hillsides along Puget Sound have resulted in occasional loss of life and costly damage to property during intense or prolonged rainfall. As part of a larger project to assess landslide hazards in the Seattle area, the U.S. Geological Survey instrumented two coastal bluff sites in 2001 to observe the subsurface hydrologic response to rainfall. The instrumentation at one of these sites, near Edmonds, Washington, consists of two rain gauges, two water-content probes that measure volumetric water content at eight depths between 0.2 and 2.0 m, and two tensiometer nests that measure soil-water suction at six depths ranging from 0.2 to 1.5m. Measurements from these instruments are used to test one- and two-dimensional numerical models of infiltration and groundwater flow. Capillary-rise tests, performed in the laboratory on soil sample from the Edmonds site, are used to define the soil hydraulic properties for the wetting process. The field observations of water content and suction show an apparent effect of porosity variation with depth on the hydraulic response to rainfall. Using a range of physical properties consistent with our laboratory and field measurements, we perform sensitivity analyses to investigate the effects of variation in physical and hydraulic properties of the soil on rainfall infiltration, pore-pressure response, and, hence, slope stability. For a two-layer-system in which the hydraulic conductivity of the upper layer is at least 10 times greater than the conductivity of the lower layer, and the infiltration rate is greater than the conductivity of the lower layer, a perched water table forms above the layer boundary potentially destabilizing the upper layer of soil. Two-dimensional modeling results indicate that the addition of a simple trench drain to the same two-layer slope has differing effects on the hydraulic response depending on the initial pressure head conditions. For slope-parallel flow conditions

  17. Arctic Submarine Slope Stability

    Science.gov (United States)

    Winkelmann, D.; Geissler, W.

    2010-12-01

    Submarine landsliding represents aside submarine earthquakes major natural hazard to coastal and sea-floor infrastructure as well as to coastal communities due to their ability to generate large-scale tsunamis with their socio-economic consequences. The investigation of submarine landslides, their conditions and trigger mechanisms, recurrence rates and potential impact remains an important task for the evaluation of risks in coastal management and offshore industrial activities. In the light of a changing globe with warming oceans and rising sea-level accompanied by increasing human population along coasts and enhanced near- and offshore activities, slope stability issues gain more importance than ever before. The Arctic exhibits the most rapid and drastic changes and is predicted to change even faster. Aside rising air temperatures, enhanced inflow of less cooled Atlantic water into the Arctic Ocean reduces sea-ice cover and warms the surroundings. Slope stability is challenged considering large areas of permafrost and hydrates. The Hinlopen/Yermak Megaslide (HYM) north of Svalbard is the first and so far only reported large-scale submarine landslide in the Arctic Ocean. The HYM exhibits the highest headwalls that have been found on siliciclastic margins. With more than 10.000 square kilometer areal extent and app. 2.400 cubic kilometer of involved sedimentary material, it is one of the largest exposed submarine slides worldwide. Geometry and age put this slide in a special position in discussing submarine slope stability on glaciated continental margins. The HYM occurred 30 ka ago, when the global sea-level dropped by app. 50 m within less than one millennium due to rapid onset of global glaciation. It probably caused a tsunami with circum-Arctic impact and wave heights exceeding 130 meters. The HYM affected the slope stability field in its neighbourhood by removal of support. Post-megaslide slope instability as expressed in creeping and smaller-scaled slides are

  18. Effect of various sources of organic carbon and high nitrite and nitrate concentrations on the selection of denitrifying bacteria. II. Continuous cultures in packed bed reactors.

    Science.gov (United States)

    Błaszczyk, M

    1983-01-01

    The effect of different organic compounds, nitrites and nitrates at the concentration of 1,000 mg N/l on the quantitative and strain-specific selection of denitrifying bacteria was determined in anaerobic packed bed reactors. Both the source of carbon and nitrogen form influenced strain specificity and the frequency of occurrence of denitrifying bacteria. The frequency of denitrifying bacteria within packed bed reactor ranged in different media from 11% (glucose and nitrates) to 100% (methanol and ethanol with nitrates). A single species selection was observed in the presence of nitrites within packed bed reactor: Pseudomonas aeruginosa in medium with acetate. Pseudomonas stutzeri in medium with ethanol, Pseudomonas mendocina in medium with methanol and Pseudomonas fluorescens in medium with glucose. When nitrates were present in packed bed reactor, the dominating bacteria were: P. stutzeri in medium with acetate, P. fluorescens in medium with ethanol, Paracoccus denitrificans in medium with methanol and Alcaligenes faecalis in medium with glucose. PMID:6194668

  19. Factors affecting seismic response of submarine slopes

    Directory of Open Access Journals (Sweden)

    G. Biscontin

    2006-01-01

    Full Text Available The response of submerged slopes on the continental shelf to seismic or storm loading has become an important element in the risk assessment for offshore structures and 'local' tsunami hazards worldwide. The geological profile of these slopes typically includes normally consolidated to lightly overconsolidated soft cohesive soils with layer thickness ranging from a few meters to hundreds of meters. The factor of safety obtained from pseudo-static analyses is not always a useful measure for evaluating the slope response, since values less than one do not necessarily imply slope failure with large movements of the soil mass. This paper addresses the relative importance of different factors affecting the response of submerged slopes during seismic loading. The analyses use a dynamic finite element code which includes a constitutive law describing the anisotropic stress-strain-strength behavior of normally consolidated to lightly overconsolidated clays. The model also incorporates anisotropic hardening to describe the effect of different shear strain and stress histories as well as bounding surface principles to provide realistic descriptions of the accumulation of the plastic strains and excess pore pressure during successive loading cycles. The paper presents results from parametric site response analyses on slope geometry and layering, soil material parameters, and input ground motion characteristics. The predicted maximum shear strains, permanent deformations, displacement time histories and maximum excess pore pressure development provide insight of slope performance during a seismic event.

  20. Effect of high sodium intake during 14 days of bed-rest on acid-base balance

    Science.gov (United States)

    Frings, P.; Baecker, N.; Heer, M.

    Lowering mechanical load like in microgravity is the dominant stimulus leading to bone loss However high dietary sodium intake is also considered as a risk factor for osteoporosis and thereby might exacerbate the microgravity induced bone loss In a metabolic balance non bed-rest study we have recently shown that a very high sodium intake leads to an increased bone resorption most likely because of a mild metabolic acidosis Frings et al FASEB J 19 5 A1345 2005 To test if mild metabolic acidosis also occurs during immobilization we examined the effect of increased dietary sodium on bone metabolism and acid-base balance in eight healthy male test subjects mean age 26 25 pm 3 49 years body weight 77 98 pm 4 34 kg in our metabolic ward during a 14-day head-down tilt HDT bed-rest study The study was designed as a randomized crossover study with two study periods Each period was divided into three parts 4 ambulatory days with 200 mmol sodium intake 14 days of bed-rest with either 550 mmol or 50 mmol sodium intake and 3 recovery days with 200 mmol sodium intake The sodium intake was altered by variations in dietary sodium chloride content Blood pH P CO2 and P O2 were analyzed in fasting morning fingertip blood samples several times during the entire study Bicarbonate HCO 3 - and base excess BE were calculated according to the Henderson-Hasselbach equation Preliminary results in the acid-base balance from the first study period 4 subjects with 550 mmol and 4 subjects with 50 mmol sodium intake strongly

  1. ElevationSlope_SLOPE3p2M

    Data.gov (United States)

    Vermont Center for Geographic Information — This metadata applies to the following collection area(s): ( and related SLOPE datasets. Created using ArcGIS "SLOPE" command to produce change in elevation over...

  2. ElevationSlope_SLOPE1p6M2010

    Data.gov (United States)

    Vermont Center for Geographic Information — This metadata applies to the following collection area(s): Missisquoi Upper 2010 1.6m and related SLOPE datasets. Created using ArcGIS "SLOPE" command to produce...

  3. in Spouted Bed

    Directory of Open Access Journals (Sweden)

    Bronislaw Buczek

    2013-01-01

    Full Text Available Samples of active coke, fresh and spent after cleaning flue gases from communal waste incinerators, were investigated. The outer layers of both coke particles were separately removed by comminution in a spouted bed. The samples of both active cokes were analysed by means of densities, mercury porosimetry, and adsorption technique. Remaining cores were examined to determine the degree of consumption of coke by the sorption of hazardous emissions (SO2, HCl, and heavy metals through its bed. Differences in contamination levels within the porous structure of the particles were estimated. The study demonstrated the effectiveness of commercial active coke in the cleaning of flue gases.

  4. Symmetry energy, its density slope, and neutron-proton effective mass splitting at normal density extracted from global nucleon optical potentials

    International Nuclear Information System (INIS)

    Based on the Hugenholtz-Van Hove theorem, it is shown that both the symmetry energy Esym(ρ) and its density slope L(ρ) at normal density ρ0 are completely determined by the nucleon global optical potentials. The latter can be extracted directly from nucleon-nucleus scatterings, (p,n) charge-exchange reactions, and single-particle energy levels of bound states. Averaging all phenomenological isovector nucleon potentials constrained by world data available in the literature since 1969, the best estimates of Esym(ρ0)=31.3 MeV and L(ρ0)=52.7 MeV are simultaneously obtained. Moreover, the corresponding neutron-proton effective mass splitting in neutron-rich matter of isospin asymmetry δ is estimated to be (mn*-mp*)/m=0.32δ.

  5. Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Rui, E-mail: Sunsr@hit.edu.cn [School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin 150001 (China); Ismail, Tamer M., E-mail: temoil@aucegypt.edu [Department of Mechanical Engineering, Suez Canal University, Ismailia (Egypt); Ren, Xiaohan [School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin 150001 (China); Abd El-Salam, M. [Department of Basic Science, Cairo University, Giza (Egypt)

    2015-05-15

    Highlights: • The effects of moisture content on the burning process of MSW are investigated. • A two-dimensional mathematical model was built to simulate the combustion process. • Temperature distributions, process rates, gas species were measured and simulated. • The The conversion ratio of C/CO and N/NO in MSW are inverse to moisture content. - Abstract: In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on the combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k–ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW.

  6. Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed

    International Nuclear Information System (INIS)

    Highlights: • The effects of moisture content on the burning process of MSW are investigated. • A two-dimensional mathematical model was built to simulate the combustion process. • Temperature distributions, process rates, gas species were measured and simulated. • The The conversion ratio of C/CO and N/NO in MSW are inverse to moisture content. - Abstract: In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on the combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k–ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW

  7. Comparison of the effect of grounding the column wall in gas-solid fluidized beds on electrostatic charge generation

    Energy Technology Data Exchange (ETDEWEB)

    Sowinski, Andrew; Mayne, Antonio; Javed, Bassam; Mehrani, Poupak, E-mail: poupak.mehrani@uottawa.ca [University of Ottawa, Chemical and Biological Engineering Department, 161 Louis Pasteur St., Ottawa, Ontario, K1N 6N5 (Canada)

    2011-06-23

    In gas-solid fluidized beds as particles are fluidized, they continuously come into contact with other particles, as well as the fluidization column wall. This generates electrostatic charges by means of triboelectrification and frictional charging, leading to particle agglomeration, reactor wall fouling, and eventually process downtime and large financial losses. Grounding the fluidization column has been considered as a means of helping electrostatic charge dissipation within fluidized beds; however, in industrial applications despite the process vessels being grounded, the electrostatic problem still persists. This work focused on the effect of fluidization column grounding on particle wall fouling. Experiments were conducted in an atmospheric system consist of a 0.1 m in diameter carbon steel fluidization column. The mass and charge-to-mass ratio (q/m) of the particles that remained adhered to the column wall upon the completion of one hour fluidization period were measured in an electrically isolated and grounded columns to quantitatively determine the amount of reactor wall fouling. Polyethylene particles with different particle size ranges (300- 1000 {mu}m) were fluidized with extra dry air at 1.5 times their respective minimum fluidization velocity (u{sub mf}). Results obtained in the grounded fluidization column were not significantly different from those in the isolated column for all particle size ranges tested where the particles mass collected and q/m and were found to be generally similar.

  8. The effect of rowing ergometry and resistive exercise on skeletal muscle structure and function during bed rest.

    Science.gov (United States)

    Krainski, Felix; Hastings, Jeffrey L; Heinicke, Katja; Romain, Nadine; Pacini, Eric L; Snell, Peter G; Wyrick, Phil; Palmer, M Dean; Haller, Ronald G; Levine, Benjamin D

    2014-06-15

    Exposure to microgravity causes functional and structural impairment of skeletal muscle. Current exercise regimens are time-consuming and insufficiently effective; an integrated countermeasure is needed that addresses musculoskeletal along with cardiovascular health. High-intensity, short-duration rowing ergometry and supplemental resistive strength exercise may achieve these goals. Twenty-seven healthy volunteers completed 5 wk of head-down-tilt bed rest (HDBR): 18 were randomized to exercise, 9 remained sedentary. Exercise consisted of rowing ergometry 6 days/wk, including interval training, and supplemental strength training 2 days/wk. Measurements before and after HDBR and following reambulation included assessment of strength, skeletal muscle volume (MRI), and muscle metabolism (magnetic resonance spectroscopy); quadriceps muscle biopsies were obtained to assess muscle fiber types, capillarization, and oxidative capacity. Sedentary bed rest (BR) led to decreased muscle volume (quadriceps: -9 ± 4%, P antigravity muscles. Due to its integrated cardiovascular benefits, rowing ergometry could be a primary component of exercise prescriptions for astronauts or patients suffering from severe deconditioning. PMID:24790012

  9. Decreasing ventromedial prefrontal cortex deactivation in risky decision making after simulated microgravity: Effects of -6 degree head-down tilt bed rest

    Directory of Open Access Journals (Sweden)

    Li-Lin eRao

    2014-05-01

    Full Text Available Space is characterized by risk and uncertainty. As humans play an important role in long-duration space missions, the ability to make risky decisions effectively is important for astronauts who spend extended time periods in space. The present study used the Balloon Analog Risk Task to conduct both behavioral and fMRI experiments to evaluate the effects of simulated microgravity on individuals’ risk-taking behavior and the neural basis of the effect. The results showed that participants’ risk-taking behavior was not affected by bed rest. However, we found that the ventromedial prefrontal cortex (VMPFC showed less deactivation after bed rest and that the VMPFC activation in the active choice condition showed no significant difference between the win outcome and the loss outcome after bed rest, although its activation was significantly greater in the win outcome than in the loss outcome before bed rest. These results suggested that the participants showed a decreased level of value calculation after the bed rest. Our findings can contribute to a better understanding of the effect of microgravity on individual higher-level cognitive functioning.

  10. Comments on the slope function

    CERN Document Server

    Kim, Minkyoo

    2016-01-01

    The exact slope function was first proposed in $SL(2)$ sector and generalized to $SU(2)$ sector later. In this note, we consider the slope function in $SU(1|1)$ sector of ${\\cal N}=4$ SYM. We derive the quantity through the method invented by N. Gromov and discuss about its validity. Further, we give comments on the slope function in deformed SYM.

  11. Long Duration Head Down Tilt Bed Rest Effects on Neurocognitive Performance: Extent, Longevity and Neural Bases

    Science.gov (United States)

    Seidler, R. D.; Mulavara, A. P.; Koppelmans, V.; Cassady, K.; Yuan, P.; Kofman, I. S.; De Dios, Y. E.; Szecsy, D. L.; Riascos-Castaneda, R F.; Wood, S. J.

    2016-01-01

    We are conducting ongoing experiments in which we are performing structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations following a six month International Space Station mission and following 70 days exposure to a spaceflight analog, head down tilt bedrest. Our central hypothesis is that measures of brain structure, function, and network integrity will change from pre to post intervention (spaceflight, bedrest). Moreover, we predict that these changes will correlate with indices of cognitive, sensory, and motor function in a neuroanatomically selective fashion. Our interdisciplinary approach utilizes cutting edge neuroimaging techniques and a broad ranging battery of sensory, motor, and cognitive assessments that will be conducted preflight, during flight, and post flight to investigate potential neuroplastic and maladaptive brain changes in crewmembers following long-duration spaceflight. Success in this endeavor would 1) result in identification of the underlying neural mechanisms and operational risks of spaceflight-induced changes in behavior, and 2) identify whether a return to normative behavioral function following re-adaptation to Earth's gravitational environment is associated with a restitution of brain structure and function or instead is supported by substitution with compensatory brain processes. In this presentation I will provide an overview of changes in behavior, brain structure, and brain function that we are observing in our bed rest participants in comparison to normative control subjects.

  12. Limited effect of fly-wheel and spinal mobilization exercise countermeasures on lumbar spine deconditioning during 90 d bed-rest in the Toulouse LTBR study

    Science.gov (United States)

    Belavý, Daniel L.; Ohshima, Hiroshi; Bareille, Marie-Pierre; Rittweger, Jörn; Felsenberg, Dieter

    2011-09-01

    We examined the effect of high-load fly-wheel (targeting the lower-limb musculature and concurrent loading of the spine via shoulder restraints) and spinal movement countermeasures against lumbar spine muscle atrophy, disc and spinal morphology changes and trunk isokinetic torque loss during prolonged bed-rest. Twenty-four male subjects underwent 90 d head-down tilt bed-rest and performed either fly-wheel (FW) exercises every three days, spinal movement exercises in lying five times daily (SpMob), or no exercise (Ctrl). There was no significant impact of countermeasures on losses of isokinetic trunk flexion/extension ( p≥0.65). Muscle volume change by day-89 of bed-rest in the psoas, iliacus, lumbar erector spinae, lumbar multifidus and quadratus lumborum, as measured via magnetic resonance imaging (MRI), was statistically similar in all three groups ( p≥0.33). No significant effect on MRI-measures of lumbar intervertebral disc volume, spinal length and lordosis ( p≥0.09) were seen either, but there was some impact ( p≤0.048) on axial plane disc dimensions (greater reduction than in Ctrl) and disc height (greater increases than in Ctrl). MRI-data from subjects measured 13 and 90-days after bed-rest showed partial recovery of the spinal extensor musculature by day-13 after bed-rest with this process complete by day-90. Some changes in lumbar spine and disc morphology parameters were still persistent 90-days after bed-rest. The present results indicate that the countermeasures tested were not optimal to maintain integrity of the spine and trunk musculature during bed rest.

  13. Assessment of highway slope failure using neural networks

    Institute of Scientific and Technical Information of China (English)

    Tsung-lin LEE; Hung-ming LIN; Yuh-pin LU

    2009-01-01

    An artificial intelligence technique of back-propagation neural networks is used to assess the slope failure. On-site slope failure data from the South Cross-Island Highway in southern Taiwan are used to test the performance of the neural network model. The numerical results demonstrate the effectiveness of artificial neural networks in the evaluation of slope failure potential based on five major factors, such as the slope gradient angle, the slope height, the cumulative precipitation, daily rainfall and strength of materials.

  14. Three-dimensional analysis of slopes reinforced with piles

    Institute of Scientific and Technical Information of China (English)

    高玉峰; 叶茂; 张飞

    2015-01-01

    Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.

  15. Removal of mercury in fixed-bed continuous upflow reactors by mercury-resistant bacteria and effect of sodium chloride on their performance

    Digital Repository Service at National Institute of Oceanography (India)

    De, J.; Leonhauser, J.; Vardanyan, L.

    Research article Removal of mercury in fixed-bed continuous upflow reactors by mercury-resistant bacteria and effect of sodium chloride on their performance Jaysankar De1,2,4,*, Johannes Leonha¨user2,5, Lilit Vardanyan3,4 ABSTRACT Urgent need to reduce...: De J, Leonha¨user J, Vardanyan L. Removal of mercury in fixed-bed continuous upflow reactors by mercury-resistant bacteria and effect of sodium chloride on their performance, QScience Connect 2014:17 http://dx.doi.org/10.5339/connect.2014.17 http...

  16. Effect of hydrogen combustion reaction on the dehydrogenation of ethane in a fixed-bed catalytic membrane reactor

    Institute of Scientific and Technical Information of China (English)

    Masoud Hasany; Mohammad Malakootikhah; Vahid Rahmanian; Soheila Yaghmaei

    2015-01-01

    A two-dimensional non-isothermal mathematical model has been developed for the ethane dehydrogenation reaction in a fixed-bed catalytic membrane reactor. Since ethane dehydrogenation is an equilibrium reaction, removal of produced hydrogen by the membrane shifts the thermodynamic equilibrium to ethylene production. For further displacement of the dehydrogenation reaction, oxidative dehydrogenation method has been used. Since ethane dehydrogenation is an endothermic reaction, the energy produced by the oxidative dehydrogena-tion method is consumed by the dehydrogenation reaction. The results show that the oxidative dehydrogenation method generated a substantial improvement in the reactor performance in terms of high conversions and significant energy saving. It was also established that the sweep gas velocity in the shell side of the reactor is one of the most important factors in the effectiveness of the reactor.

  17. Computerized spatial navigation training during 14 days of bed rest in healthy older adult men: Effect on gait performance.

    Science.gov (United States)

    Marusic, Uros; Kavcic, Voyko; Giordani, Bruno; Gerževič, Mitja; Meeusen, Romain; Pišot, Rado

    2015-06-01

    Prolonged physical inactivity or bed rest (BR) due to illness or other factors can result in significant declines in physical health and even cognitive functions. Based on random selection, 7 healthy older adult men received computerized spatial navigation training, while 8 served as active controls during 14-day BR. Greater post-BR declines were seen in normal and complex (dual-task) walking for the control as compared to intervention group, suggesting that computerized spatial navigation training can successfully moderate detrimental BR effects. Findings underline the generalization of cognitive-based intervention to the motor domain and potentially support their use to supplement BR interventions (e.g., exercise and nutrition). PMID:25938245

  18. No effect of artificial gravity on lung function with exercise training during head-down bed rest

    Science.gov (United States)

    Su, Longxiang; Guo, Yinghua; Wang, Yajuan; Wang, Delong; Liu, Changting

    2016-04-01

    The aim of this study is to explore the effectiveness of microgravity simulated by head-down bed rest (HDBR) and artificial gravity (AG) with exercise on lung function. Twenty-four volunteers were randomly divided into control and exercise countermeasure (CM) groups for 96 h of 6° HDBR. Comparisons of pulse rate, pulse oxygen saturation (SpO2) and lung function were made between these two groups at 0, 24, 48, 72, 96 h. Compared with the sitting position, inspiratory capacity and respiratory reserve volume were significantly higher than before HDBR (0° position) (P lung volume and ventilation function, but a HDBR model induced no changes in pulmonary function and therefore should not be used to study AG countermeasures.

  19. No effect of artificial gravity on lung function with exercise training during head-down bed rest

    Science.gov (United States)

    Su, Longxiang; Guo, Yinghua; Wang, Yajuan; Wang, Delong; Liu, Changting

    2016-04-01

    The aim of this study is to explore the effectiveness of microgravity simulated by head-down bed rest (HDBR) and artificial gravity (AG) with exercise on lung function. Twenty-four volunteers were randomly divided into control and exercise countermeasure (CM) groups for 96 h of 6° HDBR. Comparisons of pulse rate, pulse oxygen saturation (SpO2) and lung function were made between these two groups at 0, 24, 48, 72, 96 h. Compared with the sitting position, inspiratory capacity and respiratory reserve volume were significantly higher than before HDBR (0° position) (P rate, SpO2, pulmonary volume and pulmonary ventilation function over the HDBR observation time. Postural changes can lead to variation in lung volume and ventilation function, but a HDBR model induced no changes in pulmonary function and therefore should not be used to study AG countermeasures.

  20. Effects of composition, porosity, bedding-plane orientation, water content and a joint on the thermal conductivity of tuff

    International Nuclear Information System (INIS)

    This study deals with the effects of composition, porosity, bedding-plane orientation, water content and a joint on the thermal conductivity of tuff from the Nevada Test Site, one medium being considered for nuclear waste burial. Over the temperature range of 310 to 423 K, the thermal conductivity of dehydrated, 20% porous, welded, devitrified tuff (Grouse Canyon Member, Belted Range Tuff, G-tunnel), as measured by a linear heat-flow technique with the Dynatech comparator, increased from approximately 1.20 to 1.26 W/m-K on average, with only a small difference in temperature dependence of conductivity between samples in which heat fluxes were parallel and perpendicular to bedding. The same samples infiltrated with water to approximately 70% of pore volume displayed a 31% increase in conductivity at 310 K, on average. The thermal resistance of two additional samples from G-tunnel, each 1.27 cm long, placed together to simulate a planar joint, was within one percent of the sum of the resistances of the pieces measured separately from 300 to 373 K. This artificial joint displayed the same, essentially zero, resistance, under uniaxial pressures from 400 to 6900 kPa (60 to 1000 psi) at 373 K. Several dehydrated samples of tuff from the exploratory hole USW-Gl (Yucca Mountain) were measured from 309 to 424 K to determine the effects of composition, porosity and temperature on conductivity. Their conductivity increased several percent over this temperature range. The devitrified tuff was more conductive than the zeolitic tuff at all temperatures and conductivity declined with increasing porosity in all cases. Full water saturation produced approximately a 45% increase in conductivity in the devitrified tuff, and a 54 to 80% increase in the zeolitic at 310 K

  1. [Treatment effect of biological filtration and vegetable floating-bed combined system on greenhouse turtle breeding wastewater].

    Science.gov (United States)

    Chen, Chong-Jun; Zhang, Rui; Xiang, Kun; Wu, Wei-Xiang

    2014-08-01

    Unorganized discharge of greenhouse turtle breeding wastewater has brought several negative influences on the ecological environment in the rural area of Yangtze River Delta. Biological filtration and vegetable floating-bed combined system is a potential ecological method for greenhouse turtle breeding wastewater treatment. In order to explore the feasibility of this system and evaluate the contribution of vegetable uptake of nitrogen (N) and phosphorus (P) in treating greenhouse turtle breeding wastewater, three types of vegetables, including Ipomoea aquatica, lettuce and celery were selected in this study. Results showed the combined system had a high capacity in simultaneous removal of organic matter, N and P. The removal efficiencies of COD, NH4(+)-N, TN and TP from the wastewater reached up to 93.2%-95.6%, 97.2%-99.6%, 73.9%-93.1% and 74.9%-90.0%, respectively. System with I. aquatica had the highest efficiencies in N and P removal, followed by lettuce and celery. However, plant uptake was not the primary pathway for TN arid TP removal in the combined system. The vegetable uptake of N and P accounted for only 9.1%-25.0% of TN and TP removal from the wastewater while the effect of microorganisms would be dominant for N and P removal. In addition, the highest amounts of N and P uptake in I. aquatica were closely related with the biomass of plant. Results from the study indicated that the biological filtration and vegetable floating-bed combined system was an effective approach to treating greenhouse turtle breeding wastewater in China. PMID:25509094

  2. The effect of mixed-bed resin ingress into the Embalse PHTs

    International Nuclear Information System (INIS)

    Embalse NGS is provided four in-line autoclaves for a routine materials surveillance program. Through a cooperative program between the utility management and the Research and Development Branch of CNEA, the routine program was expanded to include Materials Tests according to the on-going R and D programs. The availability of the autoclave facilities and the joint Embalse/R and D program proved very valuable in occasion of the resin ingress into the PHTS due to the collapse of a Johnson strainer on April 9, 1988. The details of the incident have been communicated previously, and it is not the purpose of this presentation to describe the sequence of events on April 9, 1988, and following days. Rather, we present here the results of the materials surveillance program that was adopted to follow the materials behaviour and to check the possible negative impact of the resin ingress. The mixed bed resins were subjected to hydrothermal degradation under high radiation fields (the reactor went into hot shut-down state in two hours and was further cooled in a six hours' interval). Formation of ammonia, carbon dioxide, sulfate, nitrate and chloride are all possible. The long term surveillance program was carried out during the following 400 EFPD, on corrosion coupons provided by AECL and on additional samples prepared in CNEA on original materials from Embalse's PHTS. Comparisons were made of the behaviour of AECL materials ingressed in the Autoclave System in 1983, CNEA materials inserted in 1986, and additional CNEA coupons installed in 1988, after the incident

  3. Effect of dietary sodium on fluid/electrolyte regulation during bed rest

    Science.gov (United States)

    Williams, W. Jon; Schneider, Suzanne M.; Gretebeck, Randall J.; Lane, Helen W.; Stuart, Charles A.; Whitson, Peggy A.

    2003-01-01

    BACKGROUND: A negative fluid balance during bed rest (BR) is accompanied by decreased plasma volume (PV) which contributes to cardiovascular deconditioning. HYPOTHESIS: We hypothesized that increasing dietary sodium while controlling fluid intake would increase plasma osmolality (POSM), stimulate fluid conserving hormones, and reduce fluid/electrolyte (F/E) losses during BR; conversely, decreasing dietary sodium would decrease POSM, suppress fluid conserving hormones, and increase F/E losses. METHODS: We controlled fluid intake (30 ml x kg(-1) x d(-1)) in 17 men who consumed either a 4.0 +/- 0.06 g x d(-1) (174 mmol x d(-1)) (CONT; n = 6), 1.0 +/- 0.02 g x d(-1) (43 mmol x d(-1)) (LS; n = 6), or 10.0 +/- 0.04 g x d(-1) (430 mmol x d(-1)) (HS; n = 5) sodium diet before, during, and after 21 d of 6 degrees head-down BR. PV, total body water, urine volume and osmolality, POSM, and F/E controlling hormone concentrations were measured. RESULTS: In HS subjects, plasma renin activity (-92%), plasma/urinary aldosterone (-59%; -64%), and PV (-15.0%; 6.0 ml x kg(-1); p peptide (+34%) and urine antidiuretic hormone (+24%) increased during BR (p urinary aldosterone (+335%) increased with no change in PV compared with CONT (p < 0.05). Total body water did not change in any of the subjects. CONCLUSIONS: Contrary to our hypothesis, increasing dietary sodium while controlling fluid intake during BR resulted in a greater loss of PV compared with the CONT subjects. Reducing dietary sodium while controlling fluid intake did not alter the PV response during BR compared with CONT subjects.

  4. The characteristics of bed agglomeration during fluidized bed combustion of eucalyptus bark

    International Nuclear Information System (INIS)

    The bed agglomeration behaviors were investigated experimentally when eucalyptus bark was burning tested in a laboratory scale fluidized bed reactor. The focuses of this work were the influences of operating conditions and bed materials on the bed agglomeration tendency and the elucidation in the behaviors of fuel inorganic elements and the governing mode of the agglomeration. It was found that the defluidization caused by the bed agglomeration was clearly detectable from the decrease in measured bed pressure. The growth of bed particle and accumulation of agglomerates during combustion provided the partial to complete defluidization. The defluidization was promoted by the increase of bed temperature and bed particle size, and the decrease of fluidizing air velocity. The SEM-EDS analyses revealed that the bed agglomeration was mainly attributed to the formation of potassium silicate compounds as liquid phase during the combustion. This was initiated by the chemical reaction between the bed particle and the released ash constituents. In this study, the inorganic migration from fuel particle to bed particle was likely dominated by the condensation/reaction. The thermodynamic examination by ternary phase diagram analysis corroborated that the liquid phase formation of the ash derived materials controlled the agglomeration. The alumina sand prevented the bed agglomeration since it was inactive in the formation of viscous molten substances during combustion at the observed temperatures. - Highlights: • The behaviors of bed agglomeration were studied during the fluidized bed combustion of eucalyptus bark. • The increase in bed temperature and sand size, and the decrease of air velocity promoted bed defluidization. • The formation of molten potassium silicate compounds conduced to the bed agglomeration. • Condensation/reaction was the dominant inorganic migration mechanism from fuel particle to bed particle. • The alumina sand prevented effectively the bed

  5. Effects of Long-term Conservation Tillage on Soil Nutrients in Sloping Fields in Regions Characterized by Water and Wind Erosion

    Science.gov (United States)

    Tan, Chunjian; Cao, Xue; Yuan, Shuai; Wang, Weiyu; Feng, Yongzhong; Qiao, Bo

    2015-12-01

    Conservation tillage is commonly used in regions affected by water and wind erosion. To understand the effects of conservation tillage on soil nutrients and yield, a long-term experiment was set up in a region affected by water and wind erosion on the Loess Plateau. The treatments used were traditional tillage (CK), no tillage (NT), straw mulching (SM), plastic-film mulching (PM), ridging and plastic-film mulching (RPM) and intercropping (In). Our results demonstrate that the available nutrients in soils subjected to non-traditional tillage treatments decreased during the first several years and then remained stable over the last several years of the experiment. The soil organic matter and total nitrogen content increased gradually over 6 years in all treatments except CK. The nutrient content of soils subjected to conservative tillage methods, such as NT and SM, were significantly higher than those in soils under the CK treatment. Straw mulching and film mulching effectively reduced an observed decrease in soybean yield. Over the final 6 years of the experiment, soybean yields followed the trend RPM > PM > SM > NT > CK > In. This trend has implications for controlling soil erosion and preventing non-point source pollution in sloping fields by sacrificing some food production.

  6. Application of the time-dependent mild-slope equations for the simulation of wake effects in the lee of a farm of Wave Dragon wave energy converters

    OpenAIRE

    Beels, C.; P. Troch; De Visch, K.; Kofoed, J.P.; de Backer, G

    2010-01-01

    Time-dependent mild-slope equations have been extensively used to compute wave transformations near coastal and offshore structures for more than 20 years. Recently the wave absorption characteristics of a Wave Energy Converter (abbreviated as WEC) of the overtopping type have been implemented in a time-dependent mild-slope equation model by using numerical sponge layers. In this paper the developed WEC implementation is applied to a single Wave Dragon WEC and multiple Wave Dragon WECs. The W...

  7. Mycorrhizal aspects in slope stabilisation

    Science.gov (United States)

    Graf, Frank

    2016-04-01

    In order to re-colonise and stabilise slopes affected by superficial soil failure with plants essential requirements have to be met: the plants must grow the plants must survive sustainably plant succession must start and continuously develop These requirements, however, are anything but easy given, particularly under the often hostile environmental conditions dominating on bare and steep slopes. Mycorrhizal fungi, the symbiotic partners of almost all plants used in eco-engineering, are said to improve the plants' ability to overcome periods governed by strongly (growth) limiting factors. Subsequently, results of investigations are presented of mycorrhizal effects on different plant and soil functions related to eco-engineering in general and soil and slope stabilisation in particular. Generally, inoculation yielded higher biomass of the host plants above as well as below ground. Furthermore, the survival rate was higher for mycorrhized compared to non-mycorrhized plants, particularly under extreme environmental conditions. However, the scale of the mycorrhizal impact may be species specific of both the plant host as well as the fungal partner(s) and often becomes evident only after a certain time lag. Depending on the plant-fungus combination the root length per soil volume was found to be between 0 and 2.5 times higher for inoculated compared to non-inoculated specimens. On an alpine graded ski slope the survival of inoculated compared to non-treated Salix herbacea cuttings was significant after one vegetation period only for one of the three added mycorrhizal fungus species. However, after three years all of the inoculated plantlets performed significantly better than the non-inoculated controls. The analysis of the potential for producing and stabilising soil aggregates of five different ectomycorrhizal fungi showed high variation and, for the species Inocybe lacera, no significant difference compared to untreated soil. Furthermore, inoculation of Salix

  8. Effect of Different Feed Structures and Bedding on the Horizontal Spread of Campylobacter jejuni within Broiler Flocks

    Directory of Open Access Journals (Sweden)

    Birgitte Moen

    2013-10-01

    Full Text Available In this study, we investigated the effects of different feed structures and beddings on the spread of C. jejuni in broiler flocks, and the effect on the cecal microbiota. Broiler chickens raised in 24 eight-bird group cages on either rubber mat or wood shavings were fed either a wheat-based control diet (Control, a diet where 50% of the ground wheat was replaced by whole wheat prior to pelleting (Wheat, or a wheat-based diet, such as the control diet diluted with 12% oat hulls (Oat. Samples from the cloacal mucosa of all birds were taken daily for C. jejuni quantification and cecum samples were collected at the end of the experiment for C. jejuni quantification and microbiota analyses. We have shown a statistically significant effect of increased feed structure on the reduced spread of C. jejuni in chicken flocks, but no significant differences were detected between types of structure included in the feed. No significant changes in the dominating microbiota in the lower lower gastrointestinal (GI tract were observed, which indicates that feed structure only has an effect on the upper GI tract. Delaying the spread of C. jejuni in broiler flocks could, at time of slaughter, result in fewer C. jejuni-positive broilers.

  9. The Sloping Land Conversion Program in China

    DEFF Research Database (Denmark)

    Liu, Zhen

    By overcoming the barriers that limit access to financial liquidity and human resource, the Sloping Land Conversion Program (SLCP) can promote rural livelihood diversification. This paper examines this effect using a household survey data set spanning the 1999 implementation of the Sloping land...... conversion program. Our results show that SLCP works as a valid external policy intervention on rural livelihood diversification. In addition, the findings demonstrate that there exist heterogeneous effects of SLCP implementation on livelihood diversification across different rural income groups. The lower...

  10. Coherent sea-level fluctuations along the global continental slope

    OpenAIRE

    Chris W. Hughes; Meredith, Michael P

    2006-01-01

    Signals in sea-level or, more properly, sub-surface pressure (SSP; sea-level corrected for the inverse barometer effect) are expected to propagate rapidly along the continental slope due to the effect of sloping topography on wave modes, resulting in strongly correlated SSP over long-distances. Observations of such correlations around the Arctic and Antarctic are briefly reviewed, and then extended using satellite altimetry to the rest of the global continental slope. It is shown that such lo...

  11. Decision Guide for Roof Slope Selection

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, T.R.

    1988-01-01

    This decision guide has been written for personnel who are responsible for the design, construction, and replacement of Air Force roofs. It provides the necessary information and analytical tools for making prudent and cost-effective decisions regarding the amount of slope to provide in various roofing situations. Because the expertise and experience of the decision makers will vary, the guide contains both basic slope-related concepts as well as more sophisticated technical data. This breadth of information enables the less experienced user to develop an understanding of roof slope issues before applying the more sophisticated analytical tools, while the experienced user can proceed directly to the technical sections. Although much of this guide is devoted to the analysis of costs, it is not a cost-estimating document. It does, however, provide the reader with the relative costs of a variety of roof slope options; and it shows how to determine the relative cost-effectiveness of different options. The selection of the proper roof slope coupled with good roof design, a quality installation, periodic inspection, and appropriate maintenance and repair will achieve the Air Force's objective of obtaining the best possible roofing value for its buildings.

  12. Experimental investigation on single-phase pressure losses in nuclear debris beds: Identification of flow regimes and effective diameter

    International Nuclear Information System (INIS)

    Highlights: • Single-phase pressure drops versus flow rates in particle beds are measured. • Conditions are representative of the reflooding of a nuclear fuel debris bed. • Darcy, weak inertial, strong inertial and weak turbulent regimes are observed. • A Darcy–Forchheimer law is found to be a good approximation in this domain. • A predictive correlation is derived from new experimental data. - Abstract: During a severe nuclear power plant accident, the degradation of the reactor core can lead to the formation of debris beds. The main accident management procedure consists in injecting water inside the reactor vessel. Nevertheless, large uncertainties remain regarding the coolability of such debris beds. Motivated by the reduction of these uncertainties, experiments have been conducted on the CALIDE facility in order to investigate single-phase pressure losses in representative debris beds. In this paper, these results are presented and analyzed in order to identify a simple single-phase flow pressure loss correlation for debris-bed-like particle beds in reflooding conditions, which cover Darcean to Weakly Turbulent flow regimes. The first part of this work is dedicated to study macro-scale pressure losses generated by debris-bed-like particle beds, i.e., high sphericity (>80%) particle beds with relatively small size dispersion (from 1 mm to 10 mm). A Darcy–Forchheimer law, involving the sum of a linear term and a quadratic deviation, with respect to filtration velocity, has been found to be relevant to describe this behavior in Darcy, Strong Inertial and Weak Turbulent regimes. It has also been observed that, in a restricted domain (Re = 15 to Re = 30) between Darcy and Weak Inertial regimes, deviation is better described by a cubic term, which corresponds to the so-called Weak Inertial regime. The second part of this work aims at identifying expressions for coefficients of linear and quadratic terms in Darcy–Forchheimer law, in order to obtain a

  13. Experimental investigation on single-phase pressure losses in nuclear debris beds: Identification of flow regimes and effective diameter

    Energy Technology Data Exchange (ETDEWEB)

    Clavier, R., E-mail: remi.clavier@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN) – PSN-RES/SEREX/LE2M, Cadarache bât. 327, 13115 St Paul-lez-Durance (France); Chikhi, N., E-mail: nourdine.chikhi@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN) – PSN-RES/SEREX/LE2M, Cadarache bât. 327, 13115 St Paul-lez-Durance (France); Fichot, F. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN) – PSN-RES/SAG/LEPC, Cadarache bât. 700, 13115 St Paul-lez-Durance (France); Quintard, M. [Université de Toulouse – INPT – UPS – Institut de Mécanique des Fluides de Toulouse (IMFT), Allée Camille Soula, F-31400 Toulouse (France); CNRS – IMFT, F-31400 Toulouse (France)

    2015-10-15

    Highlights: • Single-phase pressure drops versus flow rates in particle beds are measured. • Conditions are representative of the reflooding of a nuclear fuel debris bed. • Darcy, weak inertial, strong inertial and weak turbulent regimes are observed. • A Darcy–Forchheimer law is found to be a good approximation in this domain. • A predictive correlation is derived from new experimental data. - Abstract: During a severe nuclear power plant accident, the degradation of the reactor core can lead to the formation of debris beds. The main accident management procedure consists in injecting water inside the reactor vessel. Nevertheless, large uncertainties remain regarding the coolability of such debris beds. Motivated by the reduction of these uncertainties, experiments have been conducted on the CALIDE facility in order to investigate single-phase pressure losses in representative debris beds. In this paper, these results are presented and analyzed in order to identify a simple single-phase flow pressure loss correlation for debris-bed-like particle beds in reflooding conditions, which cover Darcean to Weakly Turbulent flow regimes. The first part of this work is dedicated to study macro-scale pressure losses generated by debris-bed-like particle beds, i.e., high sphericity (>80%) particle beds with relatively small size dispersion (from 1 mm to 10 mm). A Darcy–Forchheimer law, involving the sum of a linear term and a quadratic deviation, with respect to filtration velocity, has been found to be relevant to describe this behavior in Darcy, Strong Inertial and Weak Turbulent regimes. It has also been observed that, in a restricted domain (Re = 15 to Re = 30) between Darcy and Weak Inertial regimes, deviation is better described by a cubic term, which corresponds to the so-called Weak Inertial regime. The second part of this work aims at identifying expressions for coefficients of linear and quadratic terms in Darcy–Forchheimer law, in order to obtain a

  14. Comparison of effects of bed depth and particle size on volatiles produced by slow pyrolysis of coal

    Energy Technology Data Exchange (ETDEWEB)

    Morris, R.M.; Pather, T.S. (University of Durban Westville, Durban (South Africa). Dept. of Chemical Engineering)

    1994-02-01

    Pyrolysis runs were carried out on Waterberg 1.4 coal with a bed depth range of 3-15 m and a particle size range of + 150 to - 2000 [mu]m, to ascertain the significance of bed depth on the yield of certain volatiles due to post pyrolysis. Factorial analysis of the runs show that bed depth has no significant influence on the yield of certain volatiles when compared with particle size, which is dominant in determining the yield of methane and carbon dioxide. The observations are explained in terms of more significant secondary reactions occurring in the diffusion of the primary products through the pores of the char.

  15. Effect of gravitational acceleration, hypokinesia and hypodynamia on the structure of the intestinal vascular bed

    Science.gov (United States)

    Nikitin, M. V.

    1980-01-01

    A series of experiments comparing single and combined effects of hypokinesia and gravitational acceleration on morphology of intestinal blood vessels are discussed. Results indicate that hypokinesia has a whole body nonspecific effect reflected even in an organ whose activity shows little or no change due to hypokinesia. In early hypokinetic stages blood redistribution caused anorexia, intestinal atonia, and secretory disruption. Destructive changes from further exposure include aneurisms, varicoses, extravascular movement of blood elements, and vascular wall muscle fiber degeneration. The effect of acceleration is greatest in the ventrodorsal direction. Changes due to acceleration then hypokinesia are like those due to hypokinesia alone; changes due to acceleration before and after hypokinesia are like those due to acceleration. Adaptation raises acceleration tolerance but the effects do not survive four-week hypokinesia.

  16. Effects of 3-day bed rest on physiological responses to graded exercise in athletes and sedentary men

    Science.gov (United States)

    Smorawinski, J.; Nazar, K.; Kaciuba-Uscilko, H.; Kaminska, E.; Cybulski, G.; Kodrzycka, A.; Bicz, B.; Greenleaf, J. E.

    2001-01-01

    To test the hypotheses that short-term bed-rest (BR) deconditioning influences metabolic, cardiorespiratory, and neurohormonal responses to exercise and that these effects depend on the subjects' training status, 12 sedentary men and 10 endurance- and 10 strength-trained athletes were submitted to 3-day BR. Before and after BR they performed incremental exercise test until volitional exhaustion. Respiratory gas exchange and heart rate (HR) were recorded continuously, and stroke volume (SV) was measured at submaximal loads. Blood was taken for lactate concentration ([LA]), epinephrine concentration ([Epi]), norepinephrine concentration ([NE]), plasma renin activity (PRA), human growth hormone concentration ([hGH]), testosterone, and cortisol determination. Reduction of peak oxygen uptake (VO(2 peak)) after BR was greater in the endurance athletes than in the remaining groups (17 vs. 10%). Decrements in VO(2 peak) correlated positively with the initial values (r = 0.73, P exercise respiratory exchange ratios were increased in athletes. Cardiac output was unchanged by BR in all groups, but exercise HR was increased and SV diminished in the sedentary subjects. The submaximal [LA] and [LA] thresholds were decreased in the endurance athletes from 71 to 60% VO(2 peak) (P exercise. These effects were insignificant in the remaining subjects. In conclusion, reduction of exercise performance and modifications in neurohormonal response to exercise after BR depend on the previous level and mode of physical training, being the most pronounced in the endurance athletes.

  17. Chronic sublethal effects of San Francisco Bay sediments on nereis (neanthes) arenaceodentata; bioaccumulation from bedded sediments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Moore, D.; Dillon, T.M.

    1993-09-01

    In previous studies with San Francisco Bay sediments, minimal chronic sublethal effects were detected (Miscellaneous Paper D-93-1 and another Miscellaneous Paper in preparation by Moore and Dillon). To ensure that the lack of effects was not due to a lack of contaminant uptake, a bioaccumulation experiment was conducted. Bioaccumulation from bedded sediments was evaluated following a 9-week exposure with the marine polychaete worm Nereis (Neanthes) arenaceodentata. Two sediments were evaluated, a contaminated San Francisco Bay test sediment and a clean control sediment from Sequim, WA. Animals were exposed as early juveniles through adulthood. Tissues were analyzed for metals, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pesticides. Worms exposed to the contaminated San Francisco Bay sediment had significantly higher tissue residues of silver (0.30 mg/kg dry weight) and tributyltin (0.298 mg/kg dry weight). Conversely, tissue residues of control animals were significantly higher in cadmium (0.67 mg/kg dry weight) and lead (1.89 mg/kg dry weight). Small Amounts (0.02 mg/kg dry weight) of aldrin and dieldrin were measured in worms exposed to the contaminated sediment, while dieldrin and 8-BHC were found in Bioaccumulation, Neanthes, Chronic sublethal, San Francisco Bay, Dredged, Material, Sediment.

  18. The Effect of Bed Rest on Bone Turnover in Young Women Hospitalized for Anorexia Nervosa: A Pilot Study

    OpenAIRE

    DiVasta, Amy D.; Feldman, Henry A.; Quach, Ashley E.; Balestrino, Maria; Gordon, Catherine M.

    2009-01-01

    Context: Malnourished adolescents with anorexia nervosa (AN) requiring medical hospitalization are at high risk for skeletal insults. Even short-term bed rest may further disrupt normal patterns of bone turnover.

  19. Effectiveness of the GAEC cross-compliance standard Short-term measures for runoff water control on sloping land (temporary ditches and grass strips in controlling soil erosion

    Directory of Open Access Journals (Sweden)

    Paolo Bazzoffi

    2011-08-01

    Full Text Available The agronomic measures made obligatory by the cross-compliance Standard Temporary measures for runoff water control on sloping land included in the Ministry of Agricultural, Food and Forestry Policies (MiPAAF decree on cross compliance until 2008, and by Standard 1.1 Creation of temporary ditches for the prevention of soil erosion in the 2009 decree, certainly appear to be useful for the control of soil erosion and runoff. The efficacy of temporary drainage ditches and of grass strips in controlling runoff and erosion has been demonstrated in trials conducted in field test plots in Italy. When level temporary drainage ditches are correctly built, namely with an inclination of not more than 2.5% in relation to the maximum hillslope gradient, they allow the suspended sediment eroded upstream to settle in the ditches, retaining the material carried away on the slope and, as a result, reducing the quantity of sediment delivered to the hydrographic network. In particular, among all the results, the erosion and runoff data in a trial conducted in Guiglia (Modena showed that in corn plots, temporary drainage ditches reduced soil erosion by 94%, from 14.4 Mg ha-1 year-1 (above the limit established by the NRCS-USDA of 11.2 Mg ha-1 year-1 to 0.8 Mg ha-1 year-1 (within the NRCS limit and also within the more restrictive limit established by the OECD of 6.0 Mg ha-1 year-1. With respect to the grass buffer strips the most significant research was carried out in Volterra. This research demonstrated their efficacy in reducing erosion from 8.15 Mg ha-1 to 1.6 Mg ha-1, which is approximately 5 times less than the erosion observed on bare soil. The effectiveness of temporary drainage ditches was also assessed through the application of the Revised Universal Soil Loss Equation (RUSLE erosion model to 60 areas under the control of the Agency for Agricultural Payments (AGEA in 2009, comparing the risk of erosion in these sample areas by simulating the presence and

  20. Shallow Water Turbulent Surface Wave Striking an Adverse Slope

    Directory of Open Access Journals (Sweden)

    Bose Sujit K.

    2015-08-01

    Full Text Available The problem of a sinusoidal wave crest striking an adverse slope due to gradual elevation of the bed is relevant for coastal sea waves. Turbulence based RANS equations are used here under turbulence closure assumptions. Depth-averaging the equations of continuity and momentum, yield two differential equations for the surface elevation and the average forward velocity. After nondimensionalization, the two equations are converted in terms of elevation over the inclined bed and the discharge, where the latter is a function of the former satisfying a first order differential equation, while the elevation is given by a first order evolution equation which is treated by Lax-Wendroff discretization. Starting initially with a single sinusoidal crest, it is shown that as time progresses, the crest leans forwards, causing a jump in the crest upfront resulting in its roll over as a jet. Three cases show that jump becomes more prominent with increasing bed inclination

  1. Effects of resource activities upon repository siting and waste containment with reference to bedded salt

    International Nuclear Information System (INIS)

    The primary consideration for the suitability of a nuclear waste repository site is the overall ability of the repository to safely contain radioactive waste. This report is a discussion of the past, present, and future effects of resource activities on waste containment. Past and present resource activities which provide release pathways (i.e., leaky boreholes, adjacent mines) will receive initial evaluation during the early stages of any repository site study. However, other resource activities which may have subtle effects on containment (e.g., long-term pumping causing increased groundwater gradients, invasion of saline water causing lower retardation) and all potential future resource activities must also be considered during the site evaluation process. Resource activities will affect both the siting and the designing of repositories. Ideally, sites should be located in areas of low resource activity and low potential for future activity, and repository design should seek to eliminate or minimize the adverse effects of any resource activity. Buffer zones should be created to provide areas in which resource activities that might adversely affect containment can be restricted or curtailed. This could mean removing large areas of land from resource development. The impact of these frozen assets should be assessed in terms of their economic value and of their effect upon resource reserves. This step could require a major effort in data acquisition and analysis followed by extensive numerical modeling of regional fluid flow and mass transport. Numerical models should be used to assess the effects of resource activity upon containment and should include the cumulative effects of different resource activities. Analysis by other methods is probably not possible except for relatively simple cases

  2. The effect of solid concentration on the secondary air-jetting penetration in a bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.H.; Lu, X.F.; Liu, H.Z.; Liu, J. [Chongqing University, Chongqing (China)

    2008-07-15

    The introduction of secondary air (SA) in fluidized bed boilers is of important engineering significance. In the present work, an experimental study on the characteristics of SA penetration is carried out by operating a bubbling fluidized bed model. Floater, the ash formed from coal combustion, is used as experimental bed material. It has an average size of 0.83 mm and a low density of 620 kg/m{sup 3}. Results indicate that the floater is more suitable to be operated in a spouted or a bubbling bed. Comparing with the conventional sand and FCC, the fluidizing characteristics of the floater are similar to those of Geldart Group D particles. From measurements of the solid concentration in the bed cross section at SA injection level by use of a solid concentration measuring thief probe of own design, the relation between SA jetting distance and SA velocity under different solid concentrations is obtained when the properties of bed material and SA ports are fixed. Furthermore, a dimensionless correlation is proposed for general cases. The results may provide a basis for further study.

  3. RMS slope of exponentially correlated surface roughness for radar applications

    DEFF Research Database (Denmark)

    Dierking, Wolfgang

    2000-01-01

    In radar signature analysis, the root mean square (RMS) surface slope is utilized to assess the relative contribution of multiple scattering effects. For an exponentially correlated surface, an effective RMS slope can be determined by truncating the high frequency tail of the roughness spectrum...

  4. Application of the Time-Dependent Mild-Slope Equations for the Simulation of Wake Effects in the Lee of a Farm of Wave Dragon Wave Energy Converters

    DEFF Research Database (Denmark)

    Beels, Charlotte; Troch, Peter; Visch, Kenneth De;

    2010-01-01

    Time-dependent mild-slope equations have been extensively used to compute wave transformations near coastal and offshore structures for more than 20 years. Recently the wave absorption characteristics of a Wave Energy Converter (abbreviated as WEC) of the overtopping type have been implemented in a...... time-dependent mild-slope equation model by using numerical sponge layers. In this paper the developed WEC implementation is applied to a single Wave Dragon WEC and multiple Wave Dragon WECs. The Wave Dragon WEC is a floating offshore converter of the overtopping type. Two wave reflectors focus the...

  5. Some effects of transverse space charge in the SNS/HIF test bed

    International Nuclear Information System (INIS)

    To assess the effect of transverse space charge in the proposed SNS/HIF simulation experiments the change in the SNS lattice parameters under the influence of transverse space-charge has been estimated by integrating the K-V beam envelope equations and approximating that for the dispersion. Using equations suggested by Garren (Proc. HIF Workshop, Berkeley 1979, LBL 10301, p 377 (1980)), periodic solutions were found for various currents. (U.K.)

  6. Effects of gamma radiation on the adult stage of bed bug Cimex lectularius L. (Hemiptera, cimicidae)

    International Nuclear Information System (INIS)

    The effects of gamma radiation doses ranging between 1 and 30 krad on the adult stage of Cimex lectularius L., were studied. The effects of irradiation on the different biological aspects of C. lectularius L., were taken in consideration. Adult irradiation affected clearly the egg production, fertility and longevity of both sexes at different mating combinations. Females were more sensitive to the sterilizing effects of gamma radiation than males, the complete sterility of both sexes in parent generation (P1) being achieved at 20 and 30 krad, respectively. The nymphal duration of first generation (F1) nymphs was greatly prolonged at all employed dosages. Our results indicated that the percent emergence of adults were reduced progressively at the dose was increased in F1 generation. The results of matings between F1 generation and individuals that had no history of radiation showed that in C. lectularius L., the genetic damage transmitted to F1 generation resulted in a greater incidence of sterility and in a reduction in the average number of eggs laid per females. (author)

  7. Model tests of geosynthetic reinforced slopes in a geotechnical centrifuge

    International Nuclear Information System (INIS)

    Geosynthetic-reinforced slopes and walls became very popular in recent years because of their financial, technical, and ecological advantages. Centrifuge modelling is a powerful tool for physical modelling of reinforced slopes and offers the advantage to observe the failure mechanisms of the slopes. In order to replicate the gravity induced stresses of a prototype structure in a geometrically 1/N reduced model, it is necessary to test the model in a gravitational field N times larger than that of the prototype structure. In this dissertation, geotextile-reinforced slope models were tested in a geotechnical centrifuge to identify the possible failure mechanisms. Slope models were tested by varying slope inclination, tensile strengths of the geotextiles, and overlapping lengths. Photographs of the geotextile reinforced slope models in flight were taken with a digital camera and the soil deformations of geotextile reinforced slopes were evaluated with Particle Image Velocimetry (PIV). The experimental results showed that failure of the centrifuge models initiated at midheight of the slope, and occurred due to geotextile breakage instead of pullout. The location of the shear surface is independent of the tensile strength of the geotextile; it is dependent on the shear strength of the soil. It is logical to see that the required acceleration of the centrifuge at slope failure was decreased with increasing slope inclination. An important contribution to the stability of the slope models was provided by the overlapping of the geotextile layers. It has a secondary reinforcement effect when it was prolonged and passed through the shear surface. Moreover, the location of the shear surface observed with PIV analysis exactly matches the tears of the retrieved geotextiles measured carefully after the centrifuge testing. It is concluded that PIV is an efficient tool to instrument the slope failures in a geotechnical centrifuge.(author)

  8. Spatial Coupling Among Landslides, Geological Structures, Cataclinal Slopes, and Fluvial Knick Zones in Nepal Himalayas

    Science.gov (United States)

    Ojha, T. P.; DeCelles, P. G.

    2014-12-01

    This work aims to identify potential landslide hazard zones in the event of heavy precipitation and seismic activity by examining spatial relationships among existing landslides, earthquake epicenters, fault zones, cataclinal (dip) slopes, anaclinal (escarp) slopes, and river steepness index in the Nepal Himalaya. In order to understand this relationship we have mapped existing landslides on Google Earth images and ESRI base maps, assembled high-resolution digital topographic data by digitizing Nepal Government published topographic maps, and gathered geological data from detailed field mapping and compilation of published geological maps. Slope angle and aspect, and dip direction and angle were extracted from GIS-based digital topographical and geological datasets to develop the new slope maps with cataclinal (dip) and anaclinal (escarp) slope distributions. Longitudinal river profiles were also extracted from high resolution DEM's derived from manually digitized contours. The slope maps with cataclinal and anaclinal slope distributions, earthquake epicenters, major geological structures, longitudinal river profiles, and landslide inventories were visualized in ESRI ArcMap 10.2 to examine the spatial correlation among landslides, fault zones, cataclinal slopes and river steepness index. We have found that landslides are spatially correlated with cataclinal slopes and fluvial knick zones with high steepness index in certain thrust boundaries. The main finding of this work is that the topographic slope threshold alone is a crude measure of landslide susceptibility. The analysis of slope using the geometric relationship among topography and geological bedding is crucial for determining landslide susceptibility in the Himalayan region.

  9. Stability Analysis for Loosened Rock Slope of Jinyang Grand Buddha in Taiyuan, China

    Science.gov (United States)

    SUN, Jinzhong; TIAN, Xiaofu; GUAN, Xudong; YU, Yonggui; YANG, Xiusheng

    On the basis of the status quo of Jinyang Grand Buddha in Taiyuan, some factors such as topography, geological structures, climate, hydrology, and engineering geology that influence the stability of the Buddha slope are considered, and several working situations of the slope that possibly suffered are presented in this article. The Buddha slope stands upright and the rock masses are composed of thick Permian sandstone, which dips slightly inward to the slope. Affected by both the incision of regional joints and the load relief to the free surface, the rock mass of the Buddha slope has turned into loosened blocks. Numerical stability analysis by FLAC-2D on the basis of the strength reduction method reveals that the localized deformation of the rock masses near the vertical surface of the slope may trigger reversing of rock beddings making the back dip slope convert into a dip slope with the possibility of plane sliding failure. Furthermore, the pseudostatic method for the dynamic process and limit equilibrium method for the static process are applied to different working situations of the Buddha slope. The analytical results illustrate that plane sliding failure will not occur when the slope is affected only by seism. However, water filling in the cracks of the loosened rock mass may greatly contribute to the potential plane sliding failure. When horizontal seism-force and hydrostatic pressure are coupled, the Buddha slope can hardly keep stable. Additionally, the loosened rock masses are prone to block toppling failure when influenced by the seism force.

  10. On the effect of cross sectional shape on incipient motion and deposition of sediments in fixed bed channels

    Directory of Open Access Journals (Sweden)

    Safari Mir-Jafar-Sadegh

    2014-03-01

    Full Text Available The condition of incipient motion and deposition are of the essential issues for the study of sediment transport. This phenomenon is of great importance to hydraulic engineers for designing sewers, drainage, as well as other rigid boundary channels. This is a study carried out with the objectives of describing the effect of cross-sectional shape on incipient motion and deposition of particles in rigid boundary channels. In this research work, the experimental data given by Loveless (1992 and Mohammadi (2005 are used. On the basis of the critical velocity approach, a new incipient motion equation for a V-shaped bottom channel and incipient deposition of sediment particles equations for rigid boundary channels having circular, rectangular, and U-shaped cross sections are obtained. New equations were compared to the other incipient motion equations. The result shows that the cross-sectional shape is an important factor for defining the minimum velocity for no-deposit particles. This study also distinguishes incipient motion of particles from incipient deposition for particles. The results may be useful for designing fixed bed channels with a limited deposition condition.

  11. Improvement parameters in dynamic compaction adjacent to the slopes

    Directory of Open Access Journals (Sweden)

    Elham Ghanbari

    2015-04-01

    Full Text Available Dynamic compaction is a cost-effective method commonly used for improvement of sandy soils. A number of researchers have investigated experimentally and numerically the improvement parameters of soils using dynamic compaction, such as crater depth, improvement depth, and radial improvement, however, these parameters are not studied for improvement adjacent to the slopes or trenches. In this research, four different slopes with different inclinations are modeled numerically using the finite element code ABAQUS, and impact loads of dynamic compaction are applied. The static factors of safety are kept similar for all trenches and determined numerically by application of gravity loads to the slope using strength reduction method (SRM. The analysis focuses on crater depth and improvement region which are compared to the state of flat ground. It can be observed that compacted area adjacent to the slopes is narrower and slightly away from the slope compared to the flat state. Moreover, crater depth increases with increase in slope inclination.

  12. Biomass pyrolysis in a fixed-bed reactor: Effects of pyrolysis parameters on product yields and characterization of products

    International Nuclear Information System (INIS)

    Slow pyrolysis of eastern giant fennel (Ferula orientalis L.) stalks has been performed in a fixed-bed tubular reactor with (ZnO, Al2O3) and without catalyst at six different temperatures ranging from 350 °C to 600 °C with heating rates of 15, 30, 50 °C/min. The amounts of bio-char, bio-oil and gas produced, as well as the compositions of the resulting bio-oils were determined by FT-IR and GC–MS. The effects of pyrolysis parameters such as temperature, catalyst and ratio of catalyst, particle size (Dp) and sweeping gas flow rate on product yields were investigated. According to results, temperature and catalyst seem to be the main factors effecting the conversion of F. orientalis L. into solid, liquid and gaseous products. The highest liquid yield (45.22%) including water was obtained with 15% zinc oxide catalyst at 500 °C temperature at a heating rate of 50 °C/min when 0.224 > Dp > 0.150 mm particle size raw material and 100 cm3/min of sweeping gas flow rate were used. - Highlights: • Ferula orientalis L. stalks were converted to solid, liquid and gaseous products. • Effects of various parameters on product yields were investigated. • 500 °C of temperature, heating rate of 50 °C/min and zinc oxide provide the optimum conditions for bio-oil formation. • 81 different compounds were identified by GC–MS in the bio-oils obtained at 500 °C

  13. Effects of cage density, sanitation frequency, and bedding type on animal wellbeing and health and cage environment in mice and rats.

    Science.gov (United States)

    Horn, Mandy J; Hudson, Shanice V; Bostrom, Linda A; Cooper, Dale M

    2012-11-01

    The objective of the current study was to evaluate the effects of cage density, sanitation frequency, and bedding type on animal growth and welfare. At weaning, Sprague-Dawley rats and C57BL/6 mice were allocated to treatment groups according to sex, bedding type (shredded aspen, cellulose, or a 50:50 mixture), and cage density and sanitation frequency (inhouse cage density standards and sanitation procedures measured against Guide recommendations) for an 8-wk period. Body weight, feed disappearance, cage ammonia, ATP concentrations, behavior, morbidity, and mortality were assessed weekly; fecal corticosterone, microbiology, and lung histopathology (rats only) were evaluated at the culmination of the trial. In both rats and mice, parameters indicative of animal health and welfare were not significantly affected by cage density and sanitation frequency or bedding type. Occasional effects of feed disappearance and cage ammonia concentrations due to density and sanitation guidelines were noted in rat cages, and bedding type affected cage ammonia and ATP concentrations. Periodic spikes of cage ammonia and ATP concentrations were recorded in mouse cages maintained according to inhouse compared with Guide standards and in cages containing aspen compared with cellulose or aspen-cellulose mixed bedding. Ongoing studies and historical data support the finding that deviations or exceptions from the cage density and sanitation frequency standards set forth in the Guide do not negatively affect animal health, welfare, or production parameters at our institution. These parameters appear to be credible measures of animal health and wellbeing and may be useful for evaluating performance standards for animal husbandry. PMID:23294884

  14. Effects of dwarf pine stands on slope deformation processes, as a basis for their management in the Hrubý Jeseník Mts

    Czech Academy of Sciences Publication Activity Database

    Roštínský, Pavel; Šenfeldr, M.; Maděra, P.

    2013-01-01

    Roč. 6, č. 1 (2013), s. 63-83. ISSN 1803-2427 Grant ostatní: GA MŠk(CZ) EE2.3.20.0004 Institutional support: RVO:68145535 Keywords : hazardous slope deformation * non-indigenous dwarf pine * management approach Subject RIV: DE - Earth Magnetism, Geodesy, Geography http://www.journaloflandscapeecology.cz/index.php?page=issues

  15. ElevationSlope_SLOPE1p6M

    Data.gov (United States)

    Vermont Center for Geographic Information — This metadata applies to the following collection area(s): Addison County 2012 1.6m; Missisquoi Upper 2010 1.6m; Missisquoi Lower 2008 1.6m and related SLOPE...

  16. Study of Bed Friction Factor for the Wu River Estuary

    Institute of Scientific and Technical Information of China (English)

    Chin-Wu LAN; Cyuan-Chen LEE

    2006-01-01

    In this research the bed friction effect is estimated of a river estuary by use of hydrodynamic analysis. The on-site sampled data of the Wu River estuary is applied to the analysis. There are many dynamic factors that affect the flow characteristics in the estuary. The effect of tide on the generation of tidal current, bottom friction and geometry effect is the focus of this paper. The Wu River estuary is about 15 km in length, with a small bottom slope and no physical obstruction; thus the incident wave at the estuary is considered a progressive wave with damping effect. The amplitude reduction and phase shift of the incident wave are analyzed. By the analysis of celerity reduction factor of the estuary, the estimated value of mean resistance coefficient M(μ,κ), damping modulus μ, and wave number κ for the sections at observation stations can be determined. Furthermore, data gathered from on-site observations are applied for validation. Finally, Manning's coefficient for each section of the observation stations can be determined. It is found that the value of Manning's coefficient is small downstream and increases towards upstream, and that the bed friction effect of an estuary varies largely. The estimated results of the paper are compared with the empirical formulas and the modified solution for practical application is discussed.

  17. MIBSA: Multi Interacting Blocks for Slope Analysis

    Science.gov (United States)

    Dattola, Giuseppe; Crosta, Giovanni; Castellanza, Riccardo; di Prisco, Claudio

    2016-04-01

    As it is well known, the slope instabilities have very important consequences in terms of human lives and activities. So predicting the evolution in time and space of slope mass movements becomes fundamental. This is even more relevant when we consider that the triggering mechanisms are a rising ground water level and the occurrence of earthquakes. Therefore, seasonal rainfall has a direct influence on the triggering of large rock and earthslide with a composite failure surface and causing differential behaviors within the sliding mass. In this contribution, a model describing the slope mass by means of an array of blocks that move on a prefixed failure surface, is defined. A shear band located at the base of each block, whose behavior is modelled via a viscous plastic model based on the Perzyna's approach, controls the slip velocity of the block. The motion of the blocks is obtained by solving the second balance equation in which the normal and tangential interaction forces are obtained by a specific interaction model. The model has been implemented in an original code and it is used to perform a parametric analysis that describes the effects of block interactions under a transient ground water oscillation. The numerical results confirm that the normal and tangential interactions between blocks can inhibit or induce the slope movements. The model is tested against some real case studies. This model is under development to add the dynamic effects generated by earthquake shaking.

  18. Effects of process parameters on quality changes of shrimp during drying in a jet-spouted bed dryer.

    Science.gov (United States)

    Niamnuy, C; Devahastin, S; Soponronnarit, S

    2007-11-01

    The objective of the present study was to investigate the effects of various parameters, that is, concentration of salt solution (2%, 3%, 4%[w/v]), boiling time (3, 5, 7 min), drying air temperature (80, 100, 120 degrees C), and size of shrimp, on the kinetics of drying and various quality attributes of shrimp, namely, shrinkage, rehydration ability, texture, colors, and microstructure, during drying in a jet-spouted bed dryer. In addition, the effects of these processing parameters on the sensory attributes of dried shrimp were also investigated. Small shrimp (350 to 360 shrimp/kg) and large shrimp (150 to 160 shrimp/kg) were boiled and then dried until their moisture content was around 25% (d.b.). It was found that the degree of color changes, toughness, and shrinkage of shrimp increased while the rehydration ability decreased with an increase in the concentration of salt solution and boiling time. Size of shrimp and drying temperature significantly affected all quality attributes of dried shrimp. The conditions that gave the highest hedonic scores of sensory evaluation for small dried shrimp are the concentration of salt solution of 2% (w/v), boiling time of 7 min, and drying air temperature of 120 degrees C. On the other hand, the conditions that gave the highest hedonic scores of sensory evaluation for large dried shrimp are the concentration of salt solution of 4% (w/v), boiling time of 7 min, and drying air temperature of 100 degrees C. The quality attributes of dried shrimp measured by instruments correlated well with the sensory attributes, especially the color of dried shrimp. PMID:18034725

  19. The effects of twelve weeks of bed rest on bone histology, biochemical markers of bone turnover, and calcium homeostasis in eleven normal subjects

    Science.gov (United States)

    Zerwekh, J. E.; Ruml, L. A.; Gottschalk, F.; Pak, C. Y.; Blomqvist, C. G. (Principal Investigator)

    1998-01-01

    This study was undertaken to examine the effects of 12 weeks of skeletal unloading on parameters of calcium homeostasis, calcitropic hormones, bone histology, and biochemical markers of bone turnover in 11 normal subjects (9 men, 2 women; 34 +/- 11 years of age). Following an ambulatory control evaluation, all subjects underwent 12 weeks of bed rest. An additional metabolic evaluation was performed after 12 days of reambulation. Bone mineral density declined at the spine (-2.9%, p = 0.092) and at the hip (-3.8%, p = 0.002 for the trochanter). Bed rest prompted a rapid, sustained, significant increase in urinary calcium and phosphorus as well as a significant increase in serum calcium. Urinary calcium increased from a pre-bed rest value of 5.3 mmol/day to values as high as 73 mmol/day during bed rest. Immunoreactive parathyroid hormone and serum 1,25-dihydroxyvitamin D declined significantly during bed rest, although the mean values remained within normal limits. Significant changes in bone histology included a suppression of osteoblastic surface for cancellous bone (3.1 +/- 1.3% to 1.9 +/- 1.5%, p = 0.0142) and increased bone resorption for both cancellous and cortical bone. Cortical eroded surface increased from 3.5 +/- 1.1% to 7.3 +/- 4.0% (p = 0.018) as did active osteoclastic surface (0.2 +/- 0.3% to 0.7 +/- 0.7%, p = 0.021). Cancellous eroded surface increased from 2.1 +/- 1.1% to 4.7 +/- 2.2% (p = 0.002), while mean active osteoclastic surface doubled (0.2 +/- 0.2% to 0.4 +/- 0.3%, p = 0.020). Serum biochemical markers of bone formation (osteocalcin, bone-specific alkaline phosphatase, and type I procollagen extension peptide) did not change significantly during bed rest. Urinary biochemical markers of bone resorption (hydroxyproline, deoxypyridinoline, and N-telopeptide of type I collagen) as well as a serum marker of bone resorption (type I collagen carboxytelopeptide) all demonstrated significant increases during bed rest which declined toward normal

  20. The Effects of Long Duration Head Down Tilt Bed Rest on Neurocognitive Performance: The Effects of Exercise Interventions

    Science.gov (United States)

    Seidler, R. D.; Mulavara, A. P.; Koppelmans, V.; Erdeniz. B.; Kofman, I. S.; DeDios, Y. E.; Szecsy, D. L.; Riascos-Castaneda, R. F.; Wood, S. J.; Bloomberg, J. J.

    2014-01-01

    We are conducting ongoing experiments in which we are performing structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations following a six month International Space Station mission and following 70 days exposure to a spaceflight analog, head down tilt bedrest. Our central hypothesis is that measures of brain structure, function, and network integrity will change from pre to post intervention (spaceflight, bedrest). Moreover, we predict that these changes will correlate with indices of cognitive, sensory, and motor function in a neuroanatomically selective fashion. Our interdisciplinary approach utilizes cutting edge neuroimaging techniques and a broad ranging battery of sensory, motor, and cognitive assessments that will be conducted pre flight, during flight, and post flight to investigate potential neuroplastic and maladaptive brain changes in crewmembers following long-duration spaceflight. Success in this endeavor would 1) result in identification of the underlying neural mechanisms and operational risks of spaceflight-induced changes in behavior, and 2) identify whether a return to normative behavioral function following re-adaptation to Earth's gravitational environment is associated with a restitution of brain structure and function or instead is supported by substitution with compensatory brain processes. Our ongoing bed rest participants are also engaging in exercise studies directed by Dr. Lori Ploutz Snyder. In this presentation, I will briefly highlight the existing literature linking exercise and fitness to brain and behavioral functions. I will also overview the metrics from my study that could be investigated in relation to the exercise and control subgroups.

  1. Effects of material properties on the competition mechanism of heat transfer of a granular bed in rotary cylinders

    International Nuclear Information System (INIS)

    Mixing and heat transfer processes of the granular materials within rotary cylinders play a key role in industrial processes. The numerical simulation is carried out by using the discrete element method (DEM) to investigate the influences of material properties on the bed mixing and heat transfer process, including heat conductivity, heat capacity, and shear modulus. Moreover, a new Péclet number is derived to determine the dominant mechanism of the heating rate within the particle bed, which is directly related to thermal and mechanical properties. The system exhibits a faster heating rate with the increase of ratio of thermal conductivity and heat capacity, or the decrease of shear modulus when inter-particle conduction dominates the heating rate; conversely, it shows a fast-mixing bed when particle convection governs the heating rate. The simulation results show good agreement with the theoretical predictions. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  2. A CFD approach on the effect of particle size on char entrainment in bubbling fluidised bed reactors

    International Nuclear Information System (INIS)

    The fluid - particle interaction inside a 41.7 mg s-1 fluidised bed reactor is modelled. Three char particles of sizes 500 μm, 250 μm, and 100 μm are injected into the fluidised bed and the momentum transport from the fluidising gas and fluidised sand is modelled. Due to the fluidising conditions and reactor design the char particles will either be entrained from the reactor or remain inside the bubbling bed. The particle size is the factor that differentiates the particle motion inside the reactor and their efficient entrainment out of it. A 3-Dimensional simulation has been performed with a completele revised momentum transport model for bubble three-phase flow according to the literature as an extension to the commercial finite volume code FLUENT 6.2.

  3. Effects of material properties on the competition mechanism of heat transfer of a granular bed in rotary cylinders

    Institute of Scientific and Technical Information of China (English)

    Xie Zhi-Yin; Feng Jun-Xiao

    2013-01-01

    Mixing and heat transfer processes of the granular materials within rotary cylinders play a key role in industrial processes.The numerical simulation is carried out by using the discrete element method (DEM) to investigate the influences of material properties on the bed mixing and heat transfer process,including heat conductivity,heat capacity,and shear modulus.Moreover,a new Péclet number is derived to determine the dominant mechanism of the heating rate within the particle bed,which is directly related to thermal and mechanical properties.The system exhibits a faster heating rate with the increase of ratio of thermal conductivity and heat capacity,or the decrease of shear modulus when inter-particle conduction dominates the heating rate; conversely,it shows a fast-mixing bed when particle convection governs the heating rate.The simulation results show good agreement with the theoretical predictions.

  4. Evaluation of the effectiveness factor along immobilized enzyme fixed-bed reactors: design of a reactor with naringinase covalently immobilized into glycophase-coated porous glass

    Energy Technology Data Exchange (ETDEWEB)

    Manjon, A.; Iborra, J.L.; Gomez, J.L.; Gomez, E.; Bastida, J.; Bodalo, A.

    1987-09-01

    A design equation is presented for packed-bed reactors containing immobilized enzymes in spherical porous particles with internal diffusion effects and obeying reversible one-intermediate Michaelis-Menten kinetics. The equation is also able to explain irreversible and competitive product inhibition kinetics. It allows the axial substrate profiles to be calculated and the dependence of the effectiveness factor along the reactor length to be continuously evaluated. The design equation was applied to explain the behavior of naringinase immobilized in Glycophase-coated porous glass operating in a packed-bed reactor and hydrolyzing both p-nitrophenyl-alpha-L-rhamnoside and naringin. The theoretically predicted results were found to fit well with experimentally measured values. (Refs. 28).

  5. A review of correlations to model the packing structure and effective thermal conductivity in packed beds of mono-sized spherical particles

    International Nuclear Information System (INIS)

    This paper presents a review of the literature describing the packing structure and effective thermal conductivity of randomly packed beds consisting of mono-sized particles. In this study particular attention was given to the packing structure (porosity, coordination number, and contact angles) and heat transfer by solid conduction, gas conduction, contact area, surface roughness, as well as thermal radiation. New methods to analyse the models were developed giving new insights into the shortcomings of the correlations to predict and define the packing structure, as well as to simulate the effective thermal conductivity in the near-wall region. This information is of particular importance in the design and operation of high temperature packed bed nuclear reactors.

  6. North Slope (Wahluke Slope) expedited response action cleanup plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    The purpose of this action is to mitigate any threat to public health and the environment from hazards on the North Slope and meet the expedited response action (ERA) objective of cleanup to a degree requiring no further action. The ERA may be the final remediation of the 100-I-3 Operable Unit. A No Action record of decision (ROD) may be issued after remediation completion. The US Department of Energy (DOE) currently owns or administers approximately 140 mi{sup 2} (about 90,000 acres) of land north and east of the Columbia River (referred to as the North Slope) that is part of the Hanford Site. The North Slope, also commonly known as the Wahluke Slope, was not used for plutonium production or support facilities; it was used for military air defense of the Hanford Site and vicinity. The North Slope contained seven antiaircraft gun emplacements and three Nike-Ajax missile positions. These military positions were vacated in 1960--1961 as the defense requirements at Hanford changed. They were demolished in 1974. Prior to government control in 1943, the North Slope was homesteaded. Since the initiation of this ERA in the summer of 1992, DOE signed the modified Hanford Federal Agreement and Consent Order (Tri-Party Agreement) with the Washington Department of Ecology (Ecology) and the US Environmental Protection Agency (EPA), in which a milestone was set to complete remediation activities and a draft closeout report by October 1994. Remediation activities will make the North Slope area available for future non-DOE uses. Thirty-nine sites have undergone limited characterization to determine if significant environmental hazards exist. This plan documents the results of that characterization and evaluates the potential remediation alternatives.

  7. North Slope (Wahluke Slope) expedited response action cleanup plan

    International Nuclear Information System (INIS)

    The purpose of this action is to mitigate any threat to public health and the environment from hazards on the North Slope and meet the expedited response action (ERA) objective of cleanup to a degree requiring no further action. The ERA may be the final remediation of the 100-I-3 Operable Unit. A No Action record of decision (ROD) may be issued after remediation completion. The US Department of Energy (DOE) currently owns or administers approximately 140 mi2 (about 90,000 acres) of land north and east of the Columbia River (referred to as the North Slope) that is part of the Hanford Site. The North Slope, also commonly known as the Wahluke Slope, was not used for plutonium production or support facilities; it was used for military air defense of the Hanford Site and vicinity. The North Slope contained seven antiaircraft gun emplacements and three Nike-Ajax missile positions. These military positions were vacated in 1960--1961 as the defense requirements at Hanford changed. They were demolished in 1974. Prior to government control in 1943, the North Slope was homesteaded. Since the initiation of this ERA in the summer of 1992, DOE signed the modified Hanford Federal Agreement and Consent Order (Tri-Party Agreement) with the Washington Department of Ecology (Ecology) and the US Environmental Protection Agency (EPA), in which a milestone was set to complete remediation activities and a draft closeout report by October 1994. Remediation activities will make the North Slope area available for future non-DOE uses. Thirty-nine sites have undergone limited characterization to determine if significant environmental hazards exist. This plan documents the results of that characterization and evaluates the potential remediation alternatives

  8. Spouted bed drying of Bauhinia forficata link extract: the effects of feed atomizer position and operating conditions on equipment performance and product properties

    OpenAIRE

    C. R. F. Souza; W. P. Oliveira

    2005-01-01

    In this paper the effects of feed atomizer position and operating conditions on equipment performance (accumulation rate, product recovery, elutriation and thermal efficiency) and product properties (moisture content, size distribution, flavonoid degradation and flow properties) during spouted bed drying of Bauhinia forficata Link extract are evaluated. The parameters studied were the position of the atomizer system (top spray or bottom spray), the inlet temperature of the spouting gas (80 an...

  9. Studies of the quality of the intraosseous dental implant bed and of thermal effects in implant pathology

    International Nuclear Information System (INIS)

    Dental implants may offer solutions to problems of tooth loss and removable dentures, avoiding the blighting of sound teeth in conventional bridgework. However, there may be severe problems due to deficient and poor quality host bone, particularly in the maxillary sinus region. The success of particulate irradiated mineralised cancellous allograft (IMCA) in generating new bone in the sinus was analysed using the trephine bone cores removed to create an implant bed. Bone cores were embedded and examined using 3D fluorescence fight microscopy and scanning electron microscopy in the backscattered electron (BSE) mode to study the quantity and the quality [degree of mineralisation] of bone in implant sites. In all graft cases, new bone as immature (woven) or mature (lamellar) bone formed on the surfaces of the allograft. The bone volume fraction was found to be significantly greater within 5 mm height of the host sinus floor. In an extended study, control sinuses grafted with IMCA soaked in saline showed no significant difference to the test side treated with the patient's own serum. IMCA was shown to retain much of its original topographical and morphological characteristics. Biopsy core specimens from other (non-sinus) sites in both maxilla and mandible were treated similarly. The highest mineral density distributions were observed in the mandible, with the lowest in the residual posterior maxilla beneath the sinus floor. A novel quantitative bone quality scale is proposed to include three parameters of bone quality: mineralisation density, bone volume fraction and connectivity. Clinical use of Laser Doppler Flowmetry (LDF) confirmed positive blood flow in grafts, sinus membrane, and oral tissues. A model of heat conduction in dental implants, predicted oral heat to be a possible factor in implant pathology. The effect of temperature on avian osteoclastic resorption in vitro was studied using a volumetric pit assay. Osteoclastic function measured as volumes and depths

  10. Preliminary investigation on the effect of earthworm and vegetation for sludge treatment in sludge treatment reed beds system.

    Science.gov (United States)

    Chen, Zhongbing; Hu, Shanshan; Hu, Chengxiao; Huang, Liangliang; Liu, Hongbo; Vymazal, Jan

    2016-06-01

    Sewage sludge treatment is becoming one of the most significant challenges for domestic wastewater management. Optimization of sludge management for reducing sludge handling cost in wastewater treatment plant is highly demanded. Sludge treatment reed bed system (STRB) is an eco-environmentally friendly technology which has a low investment input and reduced costs for operation and maintenance. The objective of this study is to evaluate the effect of earthworm assistant STRB in terms of sludge dewatering and stabilization of surplus sludge. The results show that draining and evapotranspiration (ET) take the main role for sludge dewatering; with maximum of 77 and 43 % water was removed through draining and ET, respectively. Plants improved ET rate up to 13.1 % in the planted STRB compare with the unplanted STRB. The combination of plants and earthworms increased ET rate of 20.9 % more than the control STRB (unplanted without earthworms). The planted STRB with earthworm reached the lowest water content in accumulated sludge of 46 %. There was a systematic increase of total solids (TS) concentration from 0.5 % in the influent to 25-54 % in the accumulated sludge. Earthworms enhanced the sludge stabilization dramatic with the ratio of volatile solids (VS)/TS decreased from 49 % in the influent to 18 % in the accumulated sludge in the earthworm assistant STRB. The results demonstrated a good efficiency for sludge dewatering and stabilization with the assistant of earthworms in STRBs, which can be an alternative technology for sludge treatment in wastewater treatment plants. PMID:26961527

  11. Stearic acid coating on circulating fluidized bed combustion fly ashes and its effect on the mechanical performance of polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Nina [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Zhang, Ping, E-mail: pingzhang@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010 (China); Song, Lixian; Kang, Ming; Lu, Zhongyuan [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010 (China); Zheng, Rong [Sichuan Jinhe Group Co., Ltd., Mianyang 621010 (China)

    2013-08-15

    The aim of this work was to test circulating fluidized bed combustion fly ashes (CFAs) for its potential to be utilized in polymer composites manufacturing to improve its toughness. CFAs was coated by stearic acid and used in the composite of polypropylene/ethylene vinyl acetate/high density polyethylene (PP/EVA/HDPE) by molding process method. The resulting coated and uncoated CFAs were fully characterized by particle size analyzer, contact angles, powder X-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TGA/DTA), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The stearic acid coated onto the surface of CFAs particles in the physical and chemical ways, and the total clad ratio reached 2.05% by measuring TGA/DTA curve. The percentage of CFAs particles focused to a narrow range 2–4 μm and the median mean size was 3.2 μm more than uncoated CFAs. The properties of hydrophobic and dispersive of CFAs particles improved and original activity was reserved after stearic acid coating. The stearic acid was verified as a coupling agent by how much effect it had on the mechanical properties. It showed the elongation at break of PP/EVA/HDPE reinforced with 15 wt% coated CFAs (c-CFAs) was 80.20% and higher than that of the uncoated. The stearic acid treatment of CFAs is a very promising approach to improve the mechanical strength due to the incorporation of stearic acid on the CFAs surface, and hence, further enhances the potential for recycling CFAs as a suitable filler material in polymer composites.

  12. Stearic acid coating on circulating fluidized bed combustion fly ashes and its effect on the mechanical performance of polymer composites

    International Nuclear Information System (INIS)

    The aim of this work was to test circulating fluidized bed combustion fly ashes (CFAs) for its potential to be utilized in polymer composites manufacturing to improve its toughness. CFAs was coated by stearic acid and used in the composite of polypropylene/ethylene vinyl acetate/high density polyethylene (PP/EVA/HDPE) by molding process method. The resulting coated and uncoated CFAs were fully characterized by particle size analyzer, contact angles, powder X-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TGA/DTA), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The stearic acid coated onto the surface of CFAs particles in the physical and chemical ways, and the total clad ratio reached 2.05% by measuring TGA/DTA curve. The percentage of CFAs particles focused to a narrow range 2–4 μm and the median mean size was 3.2 μm more than uncoated CFAs. The properties of hydrophobic and dispersive of CFAs particles improved and original activity was reserved after stearic acid coating. The stearic acid was verified as a coupling agent by how much effect it had on the mechanical properties. It showed the elongation at break of PP/EVA/HDPE reinforced with 15 wt% coated CFAs (c-CFAs) was 80.20% and higher than that of the uncoated. The stearic acid treatment of CFAs is a very promising approach to improve the mechanical strength due to the incorporation of stearic acid on the CFAs surface, and hence, further enhances the potential for recycling CFAs as a suitable filler material in polymer composites.

  13. Surviving Bed Rest

    Science.gov (United States)

    ... doctor will give you specific information about the duration of your bed rest. continue How Does Bed ... reading about high-risk pregnancy issues, learn about breastfeeding or how to encourage your child's development instead. ...

  14. Resonance effects on the dynamics of dense granular beds: achieving optimal energy transfer in vibrated granular systems

    NARCIS (Netherlands)

    Windows-Yule, C.R.K.; Rosato, A.D.; Thornton, A.R.; Parker, D.J.

    2015-01-01

    Using a combination of experimental techniques and discrete particle method simulations, we investigate the resonant behaviour of a dense, vibrated granular system. We demonstrate that a bed of particles driven by a vibrating plate may exhibit marked differences in its internal energy dependent on t

  15. Dynamic model development and validation for a nitrifying moving bed biofilter: Effect of temperature and influent load on the performance

    DEFF Research Database (Denmark)

    Sin, Gürkan; Weijma, Jan; Spanjers, Henri;

    2008-01-01

    A mathematical model with adequate complexity integrating hydraulics, biofilm and microbial conversion processes is successfully developed for a continuously moving bed biofilter performing tertiary nitrification. The model was calibrated and validated using data from Nether Stowey pilot plant in...... hydraulic loading had relatively negligible impact. Overall, the calibrated model can now reliably be used for design and process optimization purposes....

  16. Slope stability hazard management systems

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Weather-related geo-hazards are a major concern for both natural slopes and man-made slopes and embankments.Government agencies and private companies are increasingly required to ensure that there is adequate protection of sloping surfaces in order that interaction with the climate does not produce instability. Superior theoretical formulations and computer tools are now available to address engineering design issues related to the near ground surface soil-atmospheric interactions. An example is given in this paper that illustrates the consequences of not paying adequate attention to the hazards of slope stability prior to the construction of a highway in South America. On the other hand, examples are given from Hong Kong and Mainland China where significant benefits are derived from putting in place a hazard slope stability management system. Some results from a hazard management slope stability study related to the railway system in Canada are also reported. The study took advantage of recent research on unsaturated soil behaviour and applied this information to real-time modelling of climatic conditions. The quantification of the water balance at the ground surface, and subsequent infiltration, is used as the primary tool for hazard level assessment. The suggested hazard model can be applied at either specific high risk locations or in a more general, broad-based manner over large areas. A more thorough understanding of unsaturated soil behaviour as it applies to near ground surface soils,along with the numerical computational power of the computer has made it possible for new approaches to be used in slope hazard management engineering.

  17. An evaluation of the effects of bed rest, sleep deprivation and discontinuance of training on the physical fitness of highly trained young men

    Science.gov (United States)

    Olree, H. D.; Corbin, B.; Dugger, G.; Smith, C.

    1973-01-01

    This experiment was conducted to determine what physiological effects result when highly trained subjects are confined to bed, deprived of sleep, or allowed to discontinue training. Results indicated: (1) There was a moderate increase in strength variables due to the training in this experiment but the stress which the subjects received caused a negligible change in strength variables. (2) The training program resulted in highly significant changes in specific bicycle ergometer variables indicating good increases in cardiopulmonary fitness. Five days of bed rest or fifty hours of sleep deprivation caused comparable drastic decreases in cardiopulmonary fitness. Post stress the subjects reverted to a normal daily schedule and after two weeks they had recovered about half of what they lost. (3) Cardiac output remains relatively constant at a constant work load, but stroke volume increases with conditioning and decreases with deconditioning due to stress.

  18. Spouted bed drying of Bauhinia forficata link extract: the effects of feed atomizer position and operating conditions on equipment performance and product properties

    Directory of Open Access Journals (Sweden)

    C. R. F. Souza

    2005-06-01

    Full Text Available In this paper the effects of feed atomizer position and operating conditions on equipment performance (accumulation rate, product recovery, elutriation and thermal efficiency and product properties (moisture content, size distribution, flavonoid degradation and flow properties during spouted bed drying of Bauhinia forficata Link extract are evaluated. The parameters studied were the position of the atomizer system (top spray or bottom spray, the inlet temperature of the spouting gas (80 and 150oC and the feed mass flow rate of concentrated extract relative to the evaporation capacity of the dryer, Ws/Wmax (15 to 100%. Higher accumulation rate values were obtained with the atomizer placed at the bottom of the bed. In this configuration, the accumulation rate increases with the increase in the Ws/Wmax ratio. The best drying performance was obtained for the top spray configuration.

  19. Modeling downstream fining in sand-bed rivers. II: Application

    Science.gov (United States)

    Wright, S.; Parker, G.

    2005-01-01

    In this paper the model presented in the companion paper, Wright and Parker (2005) is applied to a generic river reach typical of a large, sand-bed river flowing into the ocean in order to investigate the mechanisms controlling longitudinal profile development and downstream fining. Three mechanisms which drive downstream fining are studied: a delta prograding into standing water, sea-level rise, and tectonic subsidence. Various rates of sea-level rise (typical of the late Holocene) and tectonic subsidence are modeled in order to quantify their effects on the degree of profile concavity and downstream fining. Also, several other physical mechanisms which may affect fining are studied, including the relative importance of the suspended versus bed load, the effect of the loss of sediment overbank, and the influence of the delta bottom slope. Finally, sensitivity analysis is used to show that the grain-size distribution at the interface between the active layer and substrate has a significant effect on downstream fining. ?? 2005 International Association of Hydraulic Engineering and Research.

  20. Area utilization efficiency of a sloping heliostat system for solar concentration

    Science.gov (United States)

    Wei, L. Y.

    1983-02-01

    Area utilization efficiency (AUE) is formulated for a sloping heliostat system facing any direction. The effects of slope shading, incidence factor, sun shading, and tower blocking by the mirrors are all taken into account. The results show that annually averaged AUEs calculated for heliostat systems (1) increase with tower height at low slope angles but less rapidly at high slopes, (2) increase monotonically with slope angle and saturate at large slopes for systems facing due south, (3) reach a maximum at a certain slope for systems facing other directions than due south, and (4) drop sharply at slopes greater than a certain value for systems facing due east or west due to slope shading effect. The results are useful for solar energy collection on non-flat terrains.

  1. Fluidised bed cereal cooking

    International Nuclear Information System (INIS)

    Man has been cooking food for thousands of years for a number of reasons: to improve flavour and palatability, sterilise, increase digestibility, improve texture and colour. Increasingly more advanced techniques are employed today in food production plants to engineer foods with many different properties. With this in mind manufacturers are constantly seeking to improve processing techniques and apply new or different technologies (such as microwaves, RF and extrusion) to develop foods with new properties (like puffed texture starches) and to increase process efficiencies (energy efficiency, water reduction). This thesis reports on work undertaken to demonstrate the potential to achieve high temperature starch conversion of whole wheat grains in a fluidised bed, thereby reducing the amount of water required and processing time. Specifically, wheat from the farm at 14% water content is cooked in a fluidised bed. The fluidised bed heats the wheat quickly by convective heating. In addition, energy can be delivered directly to the grain by microwave heating during fluidisation. Degree of starch conversion is determined by measuring the reduction in size of endotherm of reaction as observed by Differential Scanning Calorimetry. The fluidising gas, processing temperature and starting moisture content were varied in order to investigate their effect on the cooking process. A mathematical model based on energy and species concentration equations was developed to help understand the internal grain processes. The model coupled the thermal energy equation with water diffusion. The effect of water evaporation was represented as a thermal sink in the energy equation. Popular kinetic models from literature were adapted to predict the degree of starch conversion. The model gives solutions consistent with experimental data and physical intuition. A commercial computational fluid dynamics package was used to study simple airflow and particle tracks in the fluidisation column. A

  2. Effects of physical interventions on house dust mite allergen levels in carpet, bed, and upholstery dust in low-income, urban homes.

    Science.gov (United States)

    Vojta, P J; Randels, S P; Stout, J; Muilenberg, M; Burge, H A; Lynn, H; Mitchell, H; O'Connor, G T; Zeldin, D C

    2001-01-01

    House dust mite allergen exposure is a postulated risk factor for allergic sensitization, asthma development, and asthma morbidity; however, practical and effective methods to mitigate these allergens from low-income, urban home environments remain elusive. The purpose of this study was to assess the feasibility and effectiveness of physical interventions to mitigate house dust mite allergens in this setting. Homes with high levels of house dust mite allergen (Der f 1 + Der p 1 > or = 10 microg/g dust by enzyme-linked immunosorbent assay) in the bed, bedroom carpet, and/or upholstered furniture were enrolled in the study. Carpets and upholstered furniture were subjected to a single treatment of either dry steam cleaning plus vacuuming (carpet only) or intensive vacuuming alone. Bed interventions consisted of complete encasement of the mattress, box spring, and pillows plus either weekly professional or in-home laundering of nonencased bedding. Dust samples were collected at baseline and again at 3 days (carpet and upholstery only) and 2, 4, and 8 weeks posttreatment. We compared pretreatment mean allergen concentrations and loads to posttreatment values and performed between-group analyses after adjusting for differences in the pretreatment means. Both dry steam cleaning plus vacuuming and vacuuming alone resulted in a significant reduction in carpet house dust mite allergen concentration and load (p < 0.05). Levels approached pretreatment values by 4 weeks posttreatment in the intensive vacuuming group, whereas steam cleaning plus vacuuming effected a decrease that persisted for up to 8 weeks. Significant decreases in bed house dust mite allergen concentration and load were obtained in response to encasement and either professional or in-home laundering (p < 0.001). Between-group analysis revealed significantly less postintervention house dust mite allergen load in professionally laundered compared to home-laundered beds (p < 0.05). Intensive vacuuming and dry

  3. Modeling downstream fining in sand-bed rivers. I: Formulation

    Science.gov (United States)

    Wright, S.; Parker, G.

    2005-01-01

    In this paper a numerical modeling formulation is presented for simulation of the development of the longitudinal profile and bed sediment distribution in sand-bed rivers. The objective of the model application, which is presented in the companion paper (Wright and Parker, 2005), is to study the development of two characteristics of large, low-slope, sand-bed rivers: (1) a downstream decrease in bed slope (i.e. concave upward longitudinal profile) and (2) a downstream decrease in characteristic bed sediment diameter (e.g. the median bed surface size D50). Three mechanisms that lead to an upward concave profile and downstream fining are included in the modeling formulation: (1) a delta prograding into standing water at the downstream boundary, (2) sea-level rise, and (3) tectonic subsidence. In the companion paper (Wright and Parker, 2005) the model is applied to simulate the development of the longitudinal profile and downstream fining in sand-bed rivers flowing into the ocean during the past 5000 years of relatively slow sea-level rise. ?? 2005 International Association of Hydraulic Engineering and Research.

  4. ElevationSlope_SLOPE0p7M

    Data.gov (United States)

    Vermont Center for Geographic Information — This metadata applies to the following collection area(s): Windham County 2015 0.7m; Eastern VT 2014 0.7m; Rutland/GI Counties 2013 0.7m and related SLOPE datasets....

  5. DOWNWARD SLOPING DEMAND CURVES FOR STOCK AND LEVERAGE

    Directory of Open Access Journals (Sweden)

    Liem Pei Fun

    2006-01-01

    Full Text Available This research attempts to investigate the effect of downward sloping demand curves for stock on firms' financing decisions. For the same size of equity issuance, firms with steeper slope of demand curves for their stocks experience a larger price drop in their share price compare to their counterparts. As a consequence, firms with a steeper slope of demand curves are less likely to issue equity and hence they have higher leverage ratios. This research finds that the steeper the slope of demand curve for firm's stock, the higher the actual leverage of the firm. Furthermore, firms with a steeper slope of demand curves have higher target leverage ratios, signifying that these firms prefer debt to equity financing in order to avoid the adverse price impact of equity issuance on their share price.

  6. Top Ten Bed Bug Tips

    Science.gov (United States)

    ... have bed bugs, not fleas, ticks or other insects. You can compare your insect to the pictures on our Identifying bed bugs ... bedbugs Bed Bugs Home Learn about Bed Bugs — Characteristics of Bed Bugs — Finding Bed Bugs Protecting Your ...

  7. Effects of composted double-dug beds on small farmers' livelihoods in Kenya: Conservation farming with near-nil investment

    OpenAIRE

    Hamilton, P

    1997-01-01

    Metadata only record A short summary of a study undertaken during June-August 1996 promoting composting and double-dug beds for small holders in Kenya. These practices can increase food security, reduce hunger, give cash income to even the poorest farmers, greatly improve health and at the same time enhance the quality of the physical environment, thus ensuring sustainability. Includes contact information to order the full report.

  8. EFFECTIVENESS OF DISTANCE EDUCATION IN TEACHING PRACTICE FOR STUDENT TEACHERS OF B.ED PROGRAMME Issues, Predicaments & Suggestions

    OpenAIRE

    Anupama BHARGAVA

    2009-01-01

    In teacher training programme (B.Ed) period of teaching practice is considered as very demanding, hectic and exhaustive. Yet the essence of teacher training lies in it. Every year student teachers are sent for teaching practice to different schools. This period extends approximately for 21-25 days. On returning to department, as per practice, student teachers share their views, concerns, experiences and gains with their lecturers in evaluation session. This feedback proves beneficial while ma...

  9. Effect of change in patient′s bed angles on pain after coronary angiography according to vital signals

    Directory of Open Access Journals (Sweden)

    Mohamad Amin Younessi Heravi

    2015-01-01

    Full Text Available Background: One of the most common and important diagnostic methods for the detection of heart diseases is coronary angiography. The aim of this study was to determine the optimum angle of the bed by using vital signals to optimize the patient′s position after the angiography. Materials and Methods: This study was a randomized clinical trial (RCT on participants after angiography who were divided into five groups. The first group was placed routinely in a supine position. In the other groups, all of the patients were placed in bed by angle 15°, 30°, 45°, and 60° upward. In each group, vital signals were measured that included blood pressure, percent of blood oxygen saturation, heart rate, respiratory rate, and temperature. All of measured data compared with the pain score has been achieved from numerical pain scale. The data were analyzed by descriptive statistics method, variance analysis, and post hoc tests in the Statistical Package for the Social Sciences (SPSS software, version 16. Estimation of the relationship was done by MATLAB version 2011. The level of significance was considered to be 0.05. Results: In various groups, there was no significance difference in demographic variables such as gender, age, height, and weight. The mean of pain score, heart rate, systolic blood pressure, and respiratory rate changed significantly (P 0.05. It showed linear changes between pain and systolic blood pressure, respiratory rate, and heart rate changes. A dramatic reduction was also seen in systolic blood pressure, respiratory rate, heart rate, and also pain at an angle of 45 ° . Conclusion: This study showed that, 45 ° was the best angle of the bed to optimize the patient′s position after the procedure, based on his/her vital signs and pain score. Thus, in order to relive pain, this change in bed angle is advised to be planned by postangiography nurses in patients after coronary angiography.

  10. Displacement Damage Effects in Solar Cells: Mining Damage From the Microelectronics and Photonics Test Bed Space Experiment

    Science.gov (United States)

    Hardage, Donna (Technical Monitor); Walters, R. J.; Morton, T. L.; Messenger, S. R.

    2004-01-01

    The objective is to develop an improved space solar cell radiation response analysis capability and to produce a computer modeling tool which implements the analysis. This was accomplished through analysis of solar cell flight data taken on the Microelectronics and Photonics Test Bed experiment. This effort specifically addresses issues related to rapid technological change in the area of solar cells for space applications in order to enhance system performance, decrease risk, and reduce cost for future missions.

  11. Effect of the column height on the performance of liquid-solid fluidized bed for the separation of coarse slime

    Institute of Scientific and Technical Information of China (English)

    Sha Jie; Xie Guangyuan; Wang Hong; Liu Junzhang; Tang Ligang

    2012-01-01

    A liquid-solid fluidized bed separator,used for the separation of coarse slime,was developed.Test particles sized in the range from 0.25 to 0.5,0.5 to 1.0,and 0.25 to 1.0 mm were separated in the liquid-solid fluidized bed.Beds with column heights of 1200,1500,and 1800 mm were tried.The clean coal and the tailings were subsequently analyzed by float-sink testing.The results showed that the ash and yield of clean coal both decreased with increasing column height,for all three size fractions,and that the ash of the clean coal obtained from tests on the broader size fraction was less than that from the narrower sized fractions.The separation density decreased with increasing column height.The lowest E value was seen for a column height of 1500 mm,for which conditions the separation density was 1.45 g/cm3.The E value was 0.084 for the 0.25-0.5 mm fraction but the corresponding separation density was 1.48 g/cm3,and the E value 0.089,for the broader 0.25-1.0 mm fraction.

  12. Effects of Adding Corn Dried Distiller Grains with Solubles (DDGS to the Dairy Cow Diet and Effects of Bedding in Dairy Cow Slurry on Fugitive Methane Emissions

    Directory of Open Access Journals (Sweden)

    Daniel I. Massé

    2014-12-01

    Full Text Available The specific objectives of this experiment were to investigate the effects of adding 10% or 30% corn dried distillers grains with solubles (DDGS to the dairy cow diet and the effects of bedding type (wood shavings, straw or peat moss in dairy slurry on fugitive CH4 emissions. The addition of DDGS10 to the dairy cow diet significantly increased (29% the daily amount of fat excreted in slurry compared to the control diet. The inclusion of DDGS30 in the diet increased the daily amounts of excreted DM, volatile solids (VS, fat, neutral detergent fiber (NDF, acid detergent fiber (ADF and hemicellulose by 18%, 18%, 70%, 30%, 15% and 53%, respectively, compared to the control diet. During the storage experiment, daily fugitive CH4 emissions showed a significant increase of 15% (p < 0.05 for the slurry resulting from the corn DDGS30 diet. The addition of wood shavings and straw did not have a significant effect on daily fugitive CH4 emissions relative to the control diet, whereas the addition of peat moss caused a significant increase of 27% (p < 0.05 in fugitive CH4 emissions.

  13. The Effects of Dinner-to-Bed Time and Post-Dinner Walk on Gastric Cancer Across Different Age Groups: A Multicenter Case-Control Study in Southeast China.

    Science.gov (United States)

    Xu, Le; Zhang, Xi; Lu, Jun; Dai, Jia-Xi; Lin, Ren-Qin; Tian, Fang-Xi; Liang, Bing; Guo, Yi-Nan; Luo, Hui-Yu; Li, Ni; Fang, Dong-Ping; Zhao, Ruo-Hua; Huang, Chang-Ming

    2016-04-01

    Gastric cancer (GC) remains a major killer throughout the world. Despite the dramatic decrease in GC over the last century, its etiology has not yet been well characterized.This study investigated the possible independent and combined effects of the dinner-to-bed time and post-dinner walk on the risk for GC across different age groups.A population-based, case-control study was conducted in southeast China, including 452 patients with GC and 465 age-, race-, and gender-matched controls. A self-designed questionnaire was used to collect information on demographic characteristics, dinner-to-bed time, post-dinner walk, and other behavioral factors. Conditional logistic regression models were used to estimate the effects of the dinner-to-bed time and post-dinner walk as well as their joint effect on the risk for GC across different age groups.Individuals with dinner-to-bed time 55 years old. PMID:27100427

  14. An Extended Mild-Slope Equation

    Institute of Scientific and Technical Information of China (English)

    PAN Junning; HONG Guangwen; ZUO Qihua

    2000-01-01

    On the assumption that the vortex and the vertical velocity component of the current are small, a mild-slope equation for wave propagation on non-uniform flows is deduced from the basic hydrodynamic equations, with the terms of ( h h)2 and /2h h included in the equation. The terms of bottom friction, wind energy input and wave nonlinearity are also introduced into the equation. The wind energy input functions for wind waves and swells are separately considered by adopting Wen′s (1989) empirical formula for wind waves and Snyder′s observation results for swells. Thus, an extended mild-slope equation is obtained, in which the effects of refraction, diffraction, reflection, current, bottom friction, wind energy input and wave nonlinearity are considered synthetically.

  15. Stability of nuclear crater slopes in rock

    International Nuclear Information System (INIS)

    The United States Army Engineer Nuclear Cratering Group was established in 1962 to participate with the Atomic Energy Commission in a joint research and development program to develop nuclear engineering and construction technology. A major part of this research effort has been devoted to studies of the engineering properties of craters. The program to date has included field investigations of crater properties in various media over a broad range of chemical and nuclear explosive yields, studies of man-made and natural slopes, and studies directed toward the development of analytical and empirical methods of crater stability analysis. From this background, a general understanding has been developed of the effects of a cratering explosion on the surrounding medium and of physical nature of the various crater zones which are produced. The stability of nuclear crater slopes has been a subject of prime interest in the feasibility study being conducted for an Atlantic-Pacific sea-level canal. Based on experimental evidence assembled to date, nuclear crater slopes in dry dock and dry alluvium have an initially stable configuration. There have been five nuclear craters produced to date with yields of 0.4 kt or more on which observations are based and the initial configurations of these craters have remained stable for over seven years. The medium, yield, crater dimensions, and date of event for these craters are summarized. It is interesting to note that the Sedan Crater has been subjected to strong seismic motions from nearby detonations without adverse effects

  16. Exploring Slope with Stairs & Steps

    Science.gov (United States)

    Smith, Toni M.; Seshaiyer, Padmanabhan; Peixoto, Nathalia; Suh, Jennifer M.; Bagshaw, Graham; Collins, Laurena K.

    2013-01-01

    As much as ever before, mathematics teachers are searching for ways to connect mathematics to real-life scenarios within STEM contexts. As students develop skill in proportional reasoning, they examine graphical representations of linear functions, learn to associate "slope" with "steepness" and rate of change, and develop…

  17. Physiology Of Prolonged Bed Rest

    Science.gov (United States)

    Greenleaf, John E.

    1991-01-01

    Report describes physiological effects of prolonged bed rest. Rest for periods of 24 hours or longer deconditions body to some extent; healing proceeds simultaneously with deconditioning. Report provides details on shifts in fluid electrolytes and loss of lean body mass, which comprises everything in body besides fat - that is, water, muscle, and bone. Based on published research.

  18. Slope Estimation from ICESat/GLAS

    OpenAIRE

    Craig Mahoney; Natascha Kljun; Sietse O. Los; Laura Chasmer; Jorg M. Hacker; Christopher Hopkinson; North, Peter R.J.; Jacqueline A. B. Rosette; Eva van Gorsel

    2014-01-01

    We present a novel technique to infer ground slope angle from waveform LiDAR, known as the independent slope method (ISM). The technique is applied to large footprint waveforms (\\(\\sim\\) mean diameter) from the Ice, Cloud and Land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) to produce a slope dataset of near-global coverage at \\(0.5^{\\circ} \\times 0.5^{\\circ}\\) resolution. ISM slope estimates are compared against high resolution airborne LiDAR slope measurements for ...

  19. Pulsed Discharge Through Wetland Vegetation as a Control on Bed Shear Stress and Sediment Transport Affecting Everglades Restoration

    Science.gov (United States)

    Larsen, L. E.; Harvey, J. W.; Crimaldi, J. P.

    2007-12-01

    The ridge and slough landscape is a patterned peatland within the Florida Everglades in which elevated ridges of emergent vegetation are regularly interspersed among open-water sloughs with floating and submerged vegetation. Landscape features are aligned parallel to the historic flow direction. Degradation of patterning over the past 100 years coincides with diminished flow resulting from drainage and construction of levees and canals. A goal of restoration is to increase flow velocities and redistribution of particles and solutes in attempt to preserve remnant patterning and restore degraded portions of the ridge and slough landscape. To explore different management strategies that could induce sediment redistribution in the ridge and slough landscape, we simulated velocity profiles and bed shear stresses for different combinations of surface water stage, water surface slope, and vegetation community structure, based on field measurements and laboratory experiments. A mixing length approach, in which the minimum of stem spacing and distance from a solid boundary determined eddy scale, was used to simulate velocity profiles and bed shear stress in vegetated arrays. Simplified velocity profiles based only on vegetation frontal area above the bed and the Karman-Prandtl logarithmic law near the bed closely were used to approximate solutions of the one-dimensional Navier-Stokes equations for large-scale simulation. Estimates of bed shear stress were most sensitive to bed roughness, vegetation community structure, and energy slope. Importantly, our simulations illustrate that velocity and bed shear stress cannot be increased substantially in the Everglades simply by increasing surface-water stage. This result comes directly from the dependence of velocity and shear stress on vegetation frontal area and the fact that emergent vegetation stems protrude through the water column even during times of relatively deep water in the Everglades. Since merely increasing water

  20. Slope Morphology of Twin Peaks, Mars Pathfinder Landing Site

    Science.gov (United States)

    Hobbs, Steven; Paine, Colin; Clarke, Jon; Caprarelli, Graziella

    2010-05-01

    . This being the case, slope morphology results from shallow processes related to mass wasting and surface erosion, although it is obvious from the difference in slope angle between the upper and lower slopes that there is a difference either in lithology across the section of the hill, that the erosional effects were different, or that the surficial processes acting on the slopes were different. On Earth slopes frequently evolve by lower facets expanding upwards at the expense of the facet above, a process defined as slope retreat and replacement - lower slope facets replace upper slope facets. Therefore we conclude that the second possibility is more likely. The mid slope region marks a departure from symmetry with a 6˚ difference between the two sides. This may indicate separate processes operating on either side of the hill. Further investigation is currently underway to clarify the nature of the mid-hill slope differences. Additional studies are also being conducted to determine the sequence of lithologies forming the peak. References [1] Ahnert, F. (1970). Z. Geomorphol., Suppl Band 9, 88-101. [2] Kirkby, M.J. (1984). Z. Geomorphol 28(4), 405-426. [3] Young, A., (1972). Oliver and Boyd, Edinburgh. [4] Savigear, R.A.G. (1952). Trans. Inst. British Geog. 18, 31-51. [5] Pain, C.F. (1986). Catena 13, 227-239. [6] Gutierrez Elorza, M., and Sese Martinez, V.H., (2001). Geomorp.38, 19-29. [7] Montgomery, D.R. (2001). Am. J. of Sci. 301, 432-454. [8] Golombek, M. P., and N. T. Bridges (2000). J. Geophys. Res. 105(E1), 1841-1853. [9] Parker, T. J., and Rice Jr, J. W. (1997). J. Geophys. Res. 102(E11), 25,641-25,656. [10] Lucchitta, B. K., (1998) LPSC, XXIX.

  1. Anisotropy of Soil Hydraulic Properties Along Arable Slopes

    Institute of Scientific and Technical Information of China (English)

    JING Yuan-Shu; ZHANG Bin; A.THIMM; H.ZEPP

    2008-01-01

    The spatial variations of the soil hydraulic properties were mainly considered in vertical direction.The objectives of this study were to measure water-retention curves,θ(ψ),and unsaturated hydraulic conductivity functions,K(ψ),of the soils sampled at different slope positions in three directions,namely,in vertical direction,along the slope and along the contour,and to determine the effects of sampling direction and slope position of two soil catenas.At the upper slope positions,the surface soils (0-10 cm) sampled in the vertical direction had a lower soil water content,θ,at a certain soil water potential (-1500 kPa <ψ<-10 kPa) and had the greatest unsaturated hydraulic conductivity,K,at ψ> -10kPa.At the lower slope positions,K at ψ>-10 kPa was smaller in the vertical direction than in the direction along the slope.The deep soils (100-110 cm) had similar soil hydraulic properties in all the three directions.The anisotropic variations of the hydraulic properties of the surface soils were ascribed to the effects of natural wetting and drying cycles on the structural heterogeneity.These results suggested that the anisotropy of soil hydraulic properties might be significant in influencing soil water movement along the slope and need to be considered in modeling.

  2. STUDY ON THE DYNAMIC PROCESS OF RILL EROSION OF LOESS SLOPE SURFACE

    Institute of Scientific and Technical Information of China (English)

    Zhanbin LI; Kexin LU; Wenfeng DING

    2001-01-01

    Rill erosion is a dominant process of morphological evolution of the Loess Plateau in China, and deliveries much loess sediment to rivers. Data from two flume experiments conducted on the bare and glass-covered beds indicated that the fill flow develops into a series of rolling waves. The shear stress on the rill bed distributes unevenly both spatially and temporally. A new method based on the energy conservation law is proposed in this study. Thus the relationship between the runoff energy consumption from the interaction of water flow and slope bed and soil detachment is formulated. The results showed that the data for the soil detachment rate on slope (Dr) and the energy consumption of runoff (E1) fitted well with newly-developed function. The rill erosion occurs when the runoff energy consumption exceeds a critical value.

  3. Cofiring of difficult fuels: The effect of Ca-based sorbents on the gas chemistry in fluidised bed combustion; Kalsiumpohjaisten lisaeaineiden vaikutus leijukerrospolton kaasukemiaan vaikeiden polttoaineiden sekapoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Aeijaelae, M.; Partanen, J.; Fabritius, M.; Elo, T.; Virta, A.K. [Imatran Voima Oy, Vantaa (Finland)

    1997-10-01

    The objective of this project is to establish the effects of Ca-based sorbents on sulphur, halogen and alkaline chemistry in fluidised bed combustion of difficult fuels, and to find out any restrictions on the use of these sorbents. The aim is to acquire sufficient knowledge to ensure the operational reliability of power plants and to minimise the emissions and costs of flue gas cleaning. The results enable the owner to anticipate necessary changes associated with slagging, fouling and emission control in the existing power plants, when there are plans to increase the range of fuels used. (orig.)

  4. Stress and recovery assessment during simulated microgravity: Effects of exercise during a long-term head down tilt bed rest in women.

    OpenAIRE

    Karine, Weiss; Nicolas, Michel

    2009-01-01

    The aim of this study was to determine the effects of a 60-day head-down tilt long-term bed rest (HDT) on stress and recovery in sixteen healthy female volunteers. Participants were randomly assigned to either an exercise group (Exe) that followed a training program combining resistive and aerobic exercises, or to a no-exercise control group (Ctl). Psychological states were assessed using the Rest-Q, a validated questionnaire based on stress-recovery responses. A longitudinal analysis reveale...

  5. Stability of Water Lubricated Flow of Yield Stress Fluid in Sloping Pipe

    Directory of Open Access Journals (Sweden)

    Decruppe J.

    2010-06-01

    Full Text Available To facilitate the transport of viscous crudes in a pipe, an immiscible lubricating liquid, usually water, is added. In such configuration, the water migrates into the regions of high shear at the pipe wall where it lubricates the flow. The pumping pressures being balanced by wall shear stresses in the water, the flow therefore requires pressures comparable to pumping water alone, at the same total throughput [1]. So significant savings in pumping power can be derived from this process provided that it is well monitored. Indeed, instabilities usually take place at the oil/water interface and they constitute an important source of energy dissipation. Precisely, a core annular flow is known to undergo a long-wave instability of capillary type, modified by shear occuring at low Reynolds. Above a given critical Reynolds number, the flow is unstable to shorter waves which leads to an emulsification system of water droplets in oil. In present work, an experimental study of the stability of sloping plane Poiseuille flow of well characterized viscoplastic mineral oils lubricated by water was performed. The investigation was carried out by means of image analysis based on spatiotemporal diagrams (STD. Notably indicated are the effects of bed slope, flow rates ratio and oil rheology on flow stability.

  6. Effect of particle size on the average heat-transfer rate from a cylinder in a liquid-penetrated granular bed

    Science.gov (United States)

    Baluev, V. V.; Rzaev, A. I.

    1992-08-01

    Experimental results on the average heat transfer from a cylinder in a liquid-penetrated granular bed are presented and the dependence of the heat transfer rate on the particle size in the bed is found.

  7. Particle pressures in fluidized beds. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction), they impart to the bed. So rather than directly measure the particle pressure, the authors inferred the values of the elasticity from measurements of instability growth in liquid beds; the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined) and then working backwards to determine the unknown coefficients, including the elasticity.

  8. Particle Pressures in Fluidized Beds. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction): they impart to the bed. So rather than directly measure the particle pressure, we inferred the values of the elasticity from measurements of instability growth in liquid beds the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined)and then working backwards to determine the unknown coefficients, including the elasticity.

  9. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C.

    Science.gov (United States)

    Shin, Mirim; Halaki, Mark; Swan, Paul; Ireland, Angus H; Chow, Chin Moi

    2016-01-01

    The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (T a) conditions. Seventeen healthy young participants (ten males) underwent nine nights of polysomnography testing including an adaptation night. Participants were randomized to each of the three binary factors: sleepwear (cotton vs wool), bedding (polyester vs wool), and T a (17°C vs 22°C with relative humidity set at 60%). Skin temperature (T sk) and core temperature (T c) were monitored throughout the sleep period. Sleep onset latency (SOL) was significantly shortened when sleeping in wool with trends of increased total sleep time and sleep efficiency compared to cotton sleepwear. At 17°C, the proportion of sleep stages 1 (%N1) and 3 (%N3) and rapid eye movement sleep was higher, but %N2 was lower than at 22°C. Interaction effects (sleepwear × T a) showed a significantly shorter SOL for wool than cotton at 17°C but lower %N3 for wool than cotton at 22°C. A significantly lower %N2 but higher %N3 was observed for wool at 17°C than at 22°C. There was no bedding effect on sleep. Several temperature variables predicted the sleep findings in a stepwise multiple regression analysis and explained 67.8% of the variance in SOL and to a lesser degree the %N2 and %N3. These findings suggest that sleepwear played a contributory role to sleep outcomes and participants slept better at 17°C than at 22°C. PMID:27217803

  10. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C

    Directory of Open Access Journals (Sweden)

    Shin M

    2016-04-01

    Full Text Available Mirim Shin,1 Mark Halaki,1 Paul Swan,2 Angus Ireland,2 Chin Moi Chow1 1Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, 2Australian Wool Innovation Limited, The Woolmark Company, Sydney, NSW, Australia Abstract: The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (Ta conditions. Seventeen healthy young participants (ten males underwent nine nights of polysomnography testing including an adaptation night. Participants were randomized to each of the three binary factors: sleepwear (cotton vs wool, bedding (polyester vs wool, and Ta (17°C vs 22°C with relative humidity set at 60%. Skin temperature (Tsk and core temperature (Tc were monitored throughout the sleep period. Sleep onset latency (SOL was significantly shortened when sleeping in wool with trends of increased total sleep time and sleep efficiency compared to cotton sleepwear. At 17°C, the proportion of sleep stages 1 (%N1 and 3 (%N3 and rapid eye movement sleep was higher, but %N2 was lower than at 22°C. Interaction effects (sleepwear × Ta showed a significantly shorter SOL for wool than cotton at 17°C but lower %N3 for wool than cotton at 22°C. A significantly lower %N2 but higher %N3 was observed for wool at 17°C than at 22°C. There was no bedding effect on sleep. Several temperature variables predicted the sleep findings in a stepwise multiple regression analysis and explained 67.8% of the variance in SOL and to a lesser degree the %N2 and %N3. These findings suggest that sleepwear played a contributory role to sleep outcomes and participants slept better at 17°C than at 22°C.Keywords: cotton, polyester, wool, polysomnography, skin temperature, core body temperature

  11. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C

    Science.gov (United States)

    Shin, Mirim; Halaki, Mark; Swan, Paul; Ireland, Angus H; Chow, Chin Moi

    2016-01-01

    The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (Ta) conditions. Seventeen healthy young participants (ten males) underwent nine nights of polysomnography testing including an adaptation night. Participants were randomized to each of the three binary factors: sleepwear (cotton vs wool), bedding (polyester vs wool), and Ta (17°C vs 22°C with relative humidity set at 60%). Skin temperature (Tsk) and core temperature (Tc) were monitored throughout the sleep period. Sleep onset latency (SOL) was significantly shortened when sleeping in wool with trends of increased total sleep time and sleep efficiency compared to cotton sleepwear. At 17°C, the proportion of sleep stages 1 (%N1) and 3 (%N3) and rapid eye movement sleep was higher, but %N2 was lower than at 22°C. Interaction effects (sleepwear × Ta) showed a significantly shorter SOL for wool than cotton at 17°C but lower %N3 for wool than cotton at 22°C. A significantly lower %N2 but higher %N3 was observed for wool at 17°C than at 22°C. There was no bedding effect on sleep. Several temperature variables predicted the sleep findings in a stepwise multiple regression analysis and explained 67.8% of the variance in SOL and to a lesser degree the %N2 and %N3. These findings suggest that sleepwear played a contributory role to sleep outcomes and participants slept better at 17°C than at 22°C. PMID:27217803

  12. 地震动特性对岩质边坡安全系数的影响%Effects of Input Ground Motion Characters on Safety Factor of Rock Slope

    Institute of Scientific and Technical Information of China (English)

    侯红英; 郭德存; 刘红帅

    2012-01-01

    基于显式波动有限元—极限平衡法,探讨了可靠度动力安全系数的可信度,研究了地震动峰值、频谱特性对岩质边坡安全系数的影响.研究结果表明,可靠度动力安全系数改变了以往稳定性评价指标与风险评价脱钩的做法,评价结果更为科学合理;地震动峰值基本不改变安全系数时程曲线的形状,但对安全系数的概率分布和标准差影响显著,并且与边坡安全系数呈负相关关系;地震动频谱特性对边坡可靠度动力安全系数的影响最大达到25%,不应忽视.%Based on explicit fluctuations finite element- limit equilibrium method, the credibility of dynamic safety factor of reliability is explored, and the effects of peak and frequency of input ground motion on dynamic stability of rock slope are studied. The results show that, (a) the reliability dynamic safety factor is more reasonable, and can change the practice of decoupling the stability evaluation index and risk assessment, (b) the peak of input ground motion does not alter the shape of time history curve of safety factor, but significantly influences the probability distribution and standard deviation of safety factor, and has a negative relationship with safety factor of slope, and (c) the effect of frequency of input ground motion on reliability dynamic safety factor of rock slope can reach a maximum degree of 25%.

  13. Quantitative study of the damping effect of buffer strips with different slopes on runoff and pollutant removal efficiency%不同坡度缓冲带滞缓径流及污染物去除定量化

    Institute of Scientific and Technical Information of China (English)

    吴建强

    2011-01-01

    利用构建的东风港缓冲带现场试验基地和设计的径流流量测定装置,模拟上海地区农业面源污染物浓度和典型单次降雨历时及降雨量,对不同坡度缓冲带滞缓径流和农田氮磷污染物去除能力开展定量化试验研究.结果表明:相同植被缓冲带,坡度越小,其滞缓径流和土壤水力渗透的能力越强,19 m长的2%坡度缓冲带径流初始出水时间比5%坡度缓冲带延长了7.3 min,两者的渗流水量比值达到1.74;不同坡度缓冲带渗流氮磷污染物去除量显著高于径流,2%、3%、4%和5%坡度缓冲带对于氮磷污染物的渗流去除量与径流去除量的比值分别为2.32、2.15、1.82和1.64;坡度的变化对缓冲带净化面源氮磷污染物效果的影响显著,坡度越小,缓冲带渗流水量越大,其氮磷污染物的总去除率和单位面积去除负荷也越高,2%坡度缓冲带对氮磷污染的总去除率和单位面积污染去除负荷分别是5%坡度的1.56倍和1.66倍,2%坡度缓冲带对TN、NH3-N、TP的单位面积去除负荷均最高,分别达到0.661 g/m2、0.672 g/m2和0.044 g/m2.%Using the constructed buffer strip experimental site and the hydrometric devices in the Dongfeng Port of Shanghai, a quantitative study is conducted to investigate the damping effect of buffer strips with different slopes on runoff and the pollutant removal efficiency of nitrogen (N) and phosphorous (P) from agricultural lands.The result shows that for a similar configuration of vegetation structure, the gentler the slope gradient is in relation to the damping effect of buffer strips, the slower the runoff moves, and the greater the hydraulic permeability is.For example, on a 19-m long buffer strip with a 2% slope, there will be a delay of 7.3 minutes for runoff starting to flow out of the strip compared to that with a 5% slope.The two slope configurations can lead to a ratio of 1: 1.74 with respect to the seepage water.The improvement in the pollutant

  14. Analysis on long-term effects of rubble slope embankment on Qinghai-Tibet railway%青藏铁路碎石护坡路基长期效果分析

    Institute of Scientific and Technical Information of China (English)

    刘争平

    2014-01-01

    采用碎石护坡路基是多年冻土地区主要的工程处理措施。本文依据2003-2011年青藏铁路楚玛尔河地区碎石护坡路基的地温及沉降数据,对其长期效果进行分析。结果表明:采用碎石护坡路基能有效冷却地基和保护多年冻土,路基下地温总体上呈现降低趋势,竣工后2年内冻土人为上限有明显抬升,2005年以后上限基本稳定,冻土路基逐渐呈现出热稳定状态;碎石护坡对于减少路基阴阳坡的地温差异有显著作用;碎石护坡路基填筑完成后,其前期沉降较大,后期逐渐减小,2007年以后每年的沉降量均在10 mm以内,路基呈现出长期稳定状态;碎石护坡施工对铁路运行影响小,故对于冻土铁路可采用碎石护坡措施进行路基补强。%T he rubble slop embankment is the main engineering measures in permafrost region. T his paper studied the long-term effect of the rubble slope embankment according to the ground temperature and settlement data in Chumaer river region of Qinghai-Tibet railway during 2003 to 2011. The results showed that the rubble slope embankment can effectively cool foundation and protect permafrost,the ground temperature under the roadbed shows a decreasing trend and the artificial upper limit of permafrost has been uplifted obviously in two years of completion,the upper limit is beginning to stabilize after 2005 and the permafrost roadbed gradually shows in thermal stable state,the rubble slope embankment has a significant role in reducing the ground temperature difference of both sides of the roadbed,the early settlement is big and the later settlement is small after the rubble slope embankment construction,the annual settlement is within 10 mm after 2007 and the roadbed is in stable state over a long period of time,the construction of the rubble slope embankment has little effect on railway operation which means we could use the rubble slope measures for roadbed

  15. Representation of Thwaites Glacier Bed Uncertainty for Modeling Experiments

    Science.gov (United States)

    Jackson, C. S.; Goff, J. A.; Waibel, S.; Greene, C. A.; Johnson, J. V.; Young, D. A.; Blankenship, D. D.

    2013-12-01

    Thwaites catchment includes a landward sloping bed and a marine ice sheet. The sensitivity of this glacier to a warming ocean is likely dependent on specific details of its bed. Goff et al., (submitted to JGR Earth Surface) has created a conditional simulation of Thwaites Glacier bed that includes inhomogeneous statistics and channelized morphology that takes advantage of the high resolution inferences of bed geometry taken from flight paths of aerogeophysical surveys to make inferences of the type of features that are likely to exist between flight paths. This effort is now being extended to represent the uncertainties due to 1) off-nadir radar energy being interpreted inappropriately as being from bed features at nadir, 2) mischaracterization of roughness, 3) flight track spacing density, and 4) the failure to identify individual glacier carved channels. Estimates of the high-resolution bed (at 250 meter resolution) and its uncertainty will be compared against a so-called 'mass conserving' bed. The point of this effort is to capture the elements of the way ice-penetrating radar data is used to estimate ice thickness for use in modeling experiments where bed uncertainties are likely to play an important role. This exercise is interesting from an uncertainty quantification point of view insofar as while the actual uncertainties are high dimensional (i.e. every grid point that has not been observed directly), what matters to sea level rise experiments is some low-dimensional summary of what is important to glacier dynamics.

  16. Accumulation of aerosols over the Indo-Gangetic plains and southern slopes of the Himalayas: distribution, properties and radiative effects during the 2009 pre-monsoon Season

    Directory of Open Access Journals (Sweden)

    R. Gautam

    2011-05-01

    Full Text Available We examine the distribution of aerosols and associated optical/radiative properties in the Gangetic-Himalayan region from simultaneous radiometric measurements over the Indo-Gangetic Plains (IGP and the foothill/slopes of the Himalayas during the 2009 pre-monsoon season. Enhanced dust transport extending from the Southwest Asian arid regions into the IGP, results in seasonal mean (April–June aerosol optical depths of over 0.6 – highest over southern Asia. The influence of dust loading is greater over the western IGP as suggested by pronounced coarse mode peak in aerosol size distribution and spectral single scattering albedo (SSA. The transported dust in the IGP, driven by prevailing westerly airmass, is found to be more absorbing (SSA550 nm ~0.89 than the near-desert region in NW India (SSA550 nm ~0.91 suggesting mixing with carbonaceous aerosols in the IGP. On the contrary, significantly reduced dust transport is observed over eastern IGP and foothill/elevated slopes in Nepal where strongly absorbing haze is prevalent, associated with upslope transport of pollution, as indicated by low values of SSA (0.85–0.9 for the wavelength range of 440–1020 nm, suggesting presence of more absorbing aerosols compared to IGP. Assessment of the radiative impact of aerosols over NW India suggests diurnal mean reduction in solar radiation fluxes of 19–23 Wm−2 at surface (12–15 % of the surface solar insolation. Based on limited observations of aerosol optical properties during the pre-monsoon period and comparison of our radiative forcing estimates with published literature, there exists spatial heterogeneity in the regional aerosol forcing, associated with the absorbing aerosol distribution over northern India, with both diurnal mean surface forcing and forcing efficiency over the IGP exceeding that over NW India. Additionally, the role of the seasonal progressive buildup of aerosol loading and water vapor is

  17. THE EQUIVALENT SLOPE - A NEW METHOD FOR CALCULATING SOIL LOSS FROM IRREGULAR SLOPES

    Institute of Scientific and Technical Information of China (English)

    Xiaoguang ZHAO; Hui SHI; Ming'an SHAO

    2004-01-01

    The slopes in field conditions are always irregular, but the supposed uniform slopes are used in most erosion models. Some studies used several uniform slopes to approximate an irregular slope for estimating soil erosion. This approximation is both time-consuming and weak in physical insights. In this paper, the concept of equivalent slope is presented based on that runoff potential on uniform slope is equal to that of irregular slope, and the equivalent uniform slope is used to estimate soil erosion instead of the irregular slopes. The estimated results of slope-length factors for convex and concave slopes are consistent with those from the method of Foster and Wischmeier.The experiments in the southern part of the Loess Plateau in China confirmed the applicability of the present method. The method is simple and has, to some extent, clear physical meanings, and is applicable for estimating soil erosion from irregular slopes.

  18. Endogenous pancreatic polypeptide in different vascular beds

    DEFF Research Database (Denmark)

    Henriksen, J H; Schwartz, Tania; Bülow, J B

    1986-01-01

    The plasma concentration of pancreatic polypeptide (PP-like immunoreactivity) was measured in different vascular beds in order to determine regional kinetics of endogenous PP in fasting, supine subjects with normal or moderately decreased kidney function. Patients with kidney disease (n = 10) had a...... concentration (r = 0.70, P less than 0.01). Hepatic venous PP was significantly higher than systemic PP in both controls and patients with kidney disease (P less than 0.001, n = 15). The values were positively correlated (r = 0.98, P less than 0.001; slope = 1.37 +/- 0.05, P less than 0.001), indicating a...

  19. Fluidized bed heating process and apparatus

    Science.gov (United States)

    McHale, Edward J. (Inventor)

    1981-01-01

    Capacitive electrical heating of a fluidized bed enables the individual solid particles within the bed to constitute the hottest portion thereof. This effect is achieved by applying an A. C. voltage potential between dielectric coated electrodes, one of which is advantageously the wall of the fluidized bed rejection zone, sufficient to create electrical currents in said particles so as to dissipate heat therein. In the decomposition of silane or halosilanes in a fluidized bed reaction zone, such heating enhances the desired deposition of silicon product on the surface of the seed particles within the fluidized bed and minimizes undesired coating of silicon on the wall of the reaction zone and the homogeneous formation of fine silicon powder within said zone.

  20. Bed In Summer

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In winter I get up at night And dress by yellow candle-light. In summer, quite the other way, I have to go to bed by day. I have to go to bed and see The birds still hopping on the tree, Or hear the grown-up people' s feet Still going past me in the stree

  1. Fluidized bed incinerator development

    International Nuclear Information System (INIS)

    A fluidized bed incinerator is being developed for burning rad contaminated solid and liquid waste materials. In situ neutralization of acid gases by the bed material, catalytic afterburning, and gas filtration are used to produce a clean flue gas without the use of aqueous scrubbing

  2. Are tanning beds “safe”? Human studies of melanoma

    OpenAIRE

    Berwick, Marianne

    2008-01-01

    Controversy continues over the carcinogenic properties of tanning beds. The tanning industry “sells” tanning beds as a safe alternative to UV exposure for both tanning as well as vitamin D biosynthesis. But, how safe are tanning beds? Epidemiologic data – incomplete and unsatisfactory – suggests that tanning beds are not safer than solar ultraviolet radiation and that they may have independent effects from solar exposure that increase risk for melanoma.

  3. The effects of actinide separation on the radiological consequences of disposal of high-level radioactive waste on the ocean bed

    International Nuclear Information System (INIS)

    One option in the management of high-level radioactive wastes is to separate the actinides prior to vitrification and disposal. This option is examined in the context of disposal of high-level wastes on the deep ocean bed. The initial quantity of waste corresponds to the generation of 1000 GW(e)y of nuclear energy, and the actinide-separation process is assumed to remove 99% of all elements of atomic number greater than that of actinium. The models used to describe the dispersion of activity from a single disposal site on the bed of the Atlantic Ocean represent both local dispersion and long-term mixing. Collective doses and doses to individuals are calculated for six potential pathways: ingestion of fish, crustacea, molluscs, plankton and seaweed, and external irradiation from contaminated beach sediments. The period from 400 to 1,000,000 years after disposal is considered. The potential radiological impact from disposal of high-level waste without separation of actinides on the ocean bed arises from the actinides; isotopes of americium, neptunium and plutonium give the highest doses. Actinide separation would reduce these doses in proportion to the effectiveness of the separation process, until doses become determined by fission products rather than actinides: the achievable dose reduction would be a factor of approximately a hundred, or less for certain pathways. This reduction applies only to doses to the public from waste disposal: no account was taken of doses arising from the separation process itself or from the management of the separated actinides. The results of the assessment are contrasted with those of similar studies based on toxicity indices. Major deficiencies are identified in the use of toxicity indices as a basis for decision-making. (author)

  4. Bed Bug Infestations and Control Practices in China: Implications for Fighting the Global Bed Bug Resurgence

    Directory of Open Access Journals (Sweden)

    Changlu Wang

    2011-04-01

    Full Text Available The bed bug resurgence in North America, Europe, and Australia has elicited interest in investigating the causes of the widespread and increasing infestations and in developing more effective control strategies. In order to extend global perspectives on bed bug management, we reviewed bed bug literature in China by searching five Chinese language electronic databases. We also conducted telephone interviews of 68 pest control firms in two cities during March 2011. In addition, we conducted telephone interviews to 68 pest control companies within two cities in March 2011. Two species of bed bugs (Cimex lectularius L. and Cimex hemipterus (F. are known to occur in China. These were common urban pests before the early1980s. Nationwide “Four-Pest Elimination” campaigns (bed bugs being one of the targeted pests were implemented in China from 1960 to the early 1980s. These campaigns succeeded in the elimination of bed bug infestations in most communities. Commonly used bed bug control methods included applications of hot water, sealing of bed bug harborages, physical removal, and applications of residual insecticides (mainly organophosphate sprays or dusts. Although international and domestic travel has increased rapidly in China over the past decade (2000–2010, there have only been sporadic new infestations reported in recent years. During 1999–2009, all documented bed bug infestations were found in group living facilities (military dormitories, worker dormitories, and prisons, hotels, or trains. One city (Shenzhen city near Hong Kong experienced significantly higher number of bed bug infestations. This city is characterized by a high concentration of migratory factory workers. Current bed bug control practices include educating residents, washing, reducing clutter, putting items under the hot sun in summer, and applying insecticides (pyrethroids or organophosphates. There have not been any studies or reports on bed bug insecticide

  5. The effect of Al, Si and Fe contents (selective dissolution on soil physical properties at the northern slope of Mt. Kawi

    Directory of Open Access Journals (Sweden)

    I Nita

    2015-04-01

    Full Text Available A toposequence at the northern slope of Mt. Kawi (East Java, having andic properties, were studied. Soil samples at various horizons from five profiles along the toposequence were selected for this study. Selective dissolution analyses (oxalate acid, pyrophosphate and dithionite citrate extractions were performed to predict the amorphous materials, as reflected from the extracted Si, Al, and Fe. The contents of these three constituents were then correlated to the soil physical properties. The andic characters were indicated by low bulk density (0.43-0.88 g/cm3 and considerable amounts of Alo (1.3-4.2% and Feo (0.6-2%, which tended to increase with depth. As a consequence, high content of total pores (>70% and water content at pF 0, 2.54, and 4, as well as strong aggregate stability were detected (MWD of 2.4-4.5 mm and 1.4-4.5 mm, respectively, in Andisols and Non-Andisols. Water content at pF 0, 2.54, and 4, were significantly affected by respectively %Sio, % Fed, % Fep, and % Fed. However, bulk density was closely related to %Ald only.

  6. Modelling the effects of macrofauna on sediment transport and bed elevation: Application over a cross-shore mudflat profile and model validation

    Science.gov (United States)

    Orvain, Francis; Le Hir, Pierre; Sauriau, Pierre-Guy; Lefebvre, Sébastien

    2012-08-01

    The effects of 2 functional groups of bioturbators have been predicted in terms of long-term impact on erodability: (1) one superficial mobile deposit-feeder, the gastropod Hydrobia ulvae; and (2) one endobenthic deposit-feeder, the bivalve Scrobicularia plana. Different scenarios of morphodynamical cross-shore 1DH/1DV model were performed to simulate the equilibrium profile of an intertidal mudflat under tide and wave forcings. This process-based model for erosion is able to simulate multiphasic sequential resuspension, by discriminating various erosion behaviour like benthos-generated fluff-layer erosion (BGFL) and general bed loosening and burrowing activity in deep layers. The results were analysed and compared to examine the long-term effect of macrofauna after 14 years. It reveals that the impact of the bivalve S. plana is very significant after only 4 years of simulation while the effect of the gastropod H. ulvae is negligible in terms of sediment transport even after 14 years. More generally, this reveals the strong impact of stationary endobenthic bioturbators that induces a high downward shift of the upper shore while the effects of superficial motile bioturbators remain very low. This impact is mainly due to the effect of endobenthic species in deep layers associated to burrowing activities and their consequences on the bed erosion, but the production of a fluff layer by surface grazer like H. ulvae at the sediment surface can be neglected. The importance of macrofauna mediation of bed erodability is discussed in this study by comparing the activities of the two functional groups of bioturbation on the general functioning of intertidal mudflats. The model outcomes (transferred in a 1DV framework) were in close agreement with the measured results of flume data at 3 different bathymetric levels of the mudflat over the cross-shore profile. This validation step revealed that model of sediment transport under influence of biota effects does not need further

  7. Evaluation of the hydrologic system and potential effects of mining in the Dickinson lignite area, eastern slope and western Stark and Hettinger counties, North Dakota

    Science.gov (United States)

    Armstrong, C.A.

    1984-01-01

    Aquifer systems in the Dickinson lignite area of North Dakota are in sandstone beds in the Fox Hills Sandstone and lower Hell Creek Formation, in the upper Hell Creek Formation and lower Ludlow Member of the Fort Union Formation, in the upper Ludlow and lower Tongue River Members of the Fort Union Formation, and in the upper Tongue River and the Sentinel Butte Members of the Fort Union Formation. Well yields from each of the aquifer systems generally are less than 100 gallons per minute. Water in the Fox Hills-lower Hell Creek aquifer system and in the upper Hell Creek-lower Ludlow aquifer system is soft and a sodium bicarbonate type. Dissolved-solids concentrations range from 1 ,010 to 1,690 milligrams per liter. Water in the upper Ludlow-lower Tongue River aquifer system and in the upper Tongue River-Sentinel Butte aquifer system ranges from soft to very hard and generally is a sodium bicarbonate type. Dissolved-solids concentrations range from 574 to 2,720 milligrams per liter. Discharges of ground water are less than 0.1 cubic foot per second to the Cannonball River and less than 1.0 cubic foot per second to the Heart River. (USGS)

  8. Peering inside the granular bed: illuminating feedbacks between bed-load transport and bed-structure evolution

    Science.gov (United States)

    Houssais, M.; Jerolmack, D. J.; Martin, R. L.

    2013-12-01

    The threshold of motion is perhaps the most important quantity to determine for understanding rates of bed load transport, however it is a moving target. Decades of research show that it changes in space and in time within a river, and is highly variable among different systems; however, these differences are not mechanistically understood. Recent researchers have proposed that the critical Shields stress is strongly dependent on the local configuration of the sediment bed [Frey and Church, 2011]. Critical Shields stress has been observed to change following sediment-transporting flood events in natural rivers [e.g., Turowski et al., 2011], while small-scale laboratory experiments have produced declining bed load transport rates associated with slow bed compaction [Charru et al., 2004]. However, no direct measurements have been made of the evolving bed structure under bed load transport, so the connection between granular controls and the threshold of motion remains uncertain. A perspective we adopt is that granular effects determine the critical Shields stress, while the fluid supplies a distribution of driving stresses. In order to isolate the granular effect, we undertake laminar bed load transport experiments using plastic beads sheared by a viscous oil in a small, annular flume. The fluid and beads are refractive index matched, and the fluid impregnated with a fluorescing powder. When illuminated with a planar laser sheet, we are able to image slices of the granular bed while also tracking the overlying sediment transport. We present the first results showing how bed load transport influences granular packing, and how changes in packing influence the threshold of motion to feed back on bed load transport rates. This effect may account for much of the variability observed in the threshold of motion in natural streams, and by extension offers a plausible explanation for hysteresis in bed load transport rates observed during floods. Charru, F., H. Mouilleron, and

  9. HDMR methods to assess reliability in slope stability analyses

    Science.gov (United States)

    Kozubal, Janusz; Pula, Wojciech; Vessia, Giovanna

    2014-05-01

    Stability analyses of complex rock-soil deposits shall be tackled considering the complex structure of discontinuities within rock mass and embedded soil layers. These materials are characterized by a high variability in physical and mechanical properties. Thus, to calculate the slope safety factor in stability analyses two issues must be taken into account: 1) the uncertainties related to structural setting of the rock-slope mass and 2) the variability in mechanical properties of soils and rocks. High Dimensional Model Representation (HDMR) (Chowdhury et al. 2009; Chowdhury and Rao 2010) can be used to carry out the reliability index within complex rock-soil slopes when numerous random variables with high coefficient of variations are considered. HDMR implements the inverse reliability analysis, meaning that the unknown design parameters are sought provided that prescribed reliability index values are attained. Such approach uses implicit response functions according to the Response Surface Method (RSM). The simple RSM can be efficiently applied when less than four random variables are considered; as the number of variables increases, the efficiency in reliability index estimation decreases due to the great amount of calculations. Therefore, HDMR method is used to improve the computational accuracy. In this study, the sliding mechanism in Polish Flysch Carpathian Mountains have been studied by means of HDMR. The Southern part of Poland where Carpathian Mountains are placed is characterized by a rather complicated sedimentary pattern of flysh rocky-soil deposits that can be simplified into three main categories: (1) normal flysch, consisting of adjacent sandstone and shale beds of approximately equal thickness, (2) shale flysch, where shale beds are thicker than adjacent sandstone beds, and (3) sandstone flysch, where the opposite holds. Landslides occur in all flysch deposit types thus some configurations of possible unstable settings (within fractured rocky

  10. The effects of material property assumptions on predicted meltpool shape for laser powder bed fusion based additive manufacturing

    Science.gov (United States)

    Teng, Chong; Ashby, Kathryn; Phan, Nam; Pal, Deepankar; Stucker, Brent

    2016-08-01

    The objective of this study was to provide guidance on material specifications for powders used in laser powder bed fusion based additive manufacturing (AM) processes. The methodology was to investigate how different material property assumptions in a simulation affect meltpool prediction and by corrolary how different material properties affect meltpool formation in AM processes. The sensitvity of meltpool variations to each material property can be used as a guide to help drive future research and to help prioritize material specifications in requirements documents. By identifying which material properties have the greatest affect on outcomes, metrology can be tailored to focus on those properties which matter most; thus reducing costs by eliminating unnecessary testing and property charaterizations. Futhermore, this sensitivity study provides insight into which properties require more accurate measurements, thus motivating development of new metrology methods to measure those properties accurately.

  11. Effect of aeration and dilution on continuous bio ethanol production in a packed-bed bioreactor by Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Stability of cell growth was achieved continuously at a steady state in a packed-bed bioreactor. The highest productivity of ethanol was achieved (0.02 g/ L/ h) when 0.003 vvm was employed. The productivity of bio ethanol increases when dilution rate increases. The highest production of 0.037 g/ L/ h was recorded when the dilution rate (D) was at 0.05 per hour. The production of bio ethanol was successfully maintained in a non 100 b % anaerobic condition. The best aeration for the continuous production of bio ethanol in a condition of steady state growth was at an aeration rate of 0.003 vvm. (author)

  12. EFFECTIVENESS OF DISTANCE EDUCATION IN TEACHING PRACTICE FOR STUDENT TEACHERS OF B.ED PROGRAMME Issues, Predicaments & Suggestions

    Directory of Open Access Journals (Sweden)

    Anupama BHARGAVA

    2009-04-01

    Full Text Available In teacher training programme (B.Ed period of teaching practice is considered as very demanding, hectic and exhaustive. Yet the essence of teacher training lies in it. Every year student teachers are sent for teaching practice to different schools. This period extends approximately for 21-25 days. On returning to department, as per practice, student teachers share their views, concerns, experiences and gains with their lecturers in evaluation session. This feedback proves beneficial while making plans for next session. For last four years, some problems, experiences, impediments remain same for most of the students. This paper takes into account the various predicaments faced by student teachers and ways to strengthen the teaching practice so that reflective teaching practice can be encouraged.

  13. Effects of 1-week head-down tilt bed rest on bone formation and the calcium endocrine system

    Science.gov (United States)

    Arnaud, Sara B.; Whalen, Robert T.; Fung, Paul; Sherrard, Donald J.; Maloney, Norma

    1992-01-01

    The -6-deg head-down tilt (HDT) is employed in the study of 8 subjects to determine early responses in human bone and calcium endocrines during spaceflight. The average rates of bone formation in the iliac crest are determined by means of a single-dose labeling schedule and are found to decrease in 6 of the subjects. The decrease varies directly with walking miles, and increased excretion of urinary Ca and Na are observed preceding increased levels of ionized serum calcium on a bed-rest day late in the week. Reduced phosphorous excretions are also followed by increased serum phosphorous on day six, and reductions are noted in parathyroid hormone and vitamin D by the end of the experiment. The data demonstrate the responsiveness of the skeletal system to biomechanical stimuli such as the HDT.

  14. Effective bio-treatment of fresh leachate from pretreated municipal solid waste in an expanded granular sludge bed bioreactor.

    Science.gov (United States)

    Liu, Jianyong; Zhong, Jiangping; Wang, Yilan; Liu, Qiang; Qian, Guangren; Zhong, Liyun; Guo, Rongzhong; Zhang, Peijun; Xu, Zhi Ping

    2010-03-01

    This research investigated the anaerobic biodegradation of fresh leachate from pretreated municipal solid waste (MSW) in an expanded granular sludge bed (EGSB) bioreactor under mesophilic conditions. The observations showed that this bioreactor, inoculated with anaerobic granular sludge, could be readily activated. The chemical oxygen demand (COD) removal efficiency varied between 88% and 97% under normal operation conditions, and was kept at 94-96% under the proposed optimal conditions. We noted that 60-80% of the produced biogas was methane that was yielded at a rate depending on the organic loading rate (OLR) and the liquid up-flow velocity (Vup). Significantly, 80% of loaded COD or 83% of biodegraded COD was converted to methane under the proposed optimal conditions. These findings indicate that the fresh leachate from pretreated MSW can be efficiently treated in the EGSB bioreactor, and moreover, methane, a renewable energy, can be continuously generated. PMID:19640701

  15. Modelling glacier-bed overdeepenings and possible future lakes for the glaciers in the Himalaya-Karakoram region

    DEFF Research Database (Denmark)

    Linsbauer, A.; Frey, H.; Haeberli, W.;

    2016-01-01

    Surface digital elevation models (DEMs) and slope-related estimates of glacier thickness enable modelling of glacier-bed topographies over large ice-covered areas. Due to the erosive power of glaciers, such bed topographies can contain numerous overdeepenings, which when exposed following glacier...... retreat may fill with water and form new lakes. In this study, the bed overdeepenings for ∼28000 glaciers (40 775km2) of the Himalaya-Karakoram region are modelled using GlabTop2 (Glacier Bed Topography model version 2), in which ice thickness is inferred from surface slope by parameterizing basal shear...... stress as a function of elevation range for each glacier. The modelled ice thicknesses are uncertain (±30%), but spatial patterns of ice thickness and bed elevation primarily depend on surface slopes as derived from the DEM and, hence, are more robust. About 16 000 overdeepenings larger than 104m2 were...

  16. The early-warning effects of assimilation of the observations over the large-scale slope of the "World Roof" on its downstream weather forecasting

    Institute of Scientific and Technical Information of China (English)

    PENG ShiQiu; XU XiangDe; SHI XiaoHui; WANG DongXiao; ZHU YuXiang; PU JingJiao

    2009-01-01

    To improve the numerical simulation of the severe snow storms occurred in the south of China and the middle/lower reaches of Changjiang River during January of 2008, the observations from the automatic weather stations (AWS) over the Qinghai-Xizang Plateau (QXP) and its surrounding areas were assimi-lated into the Weather Research and Forecasts (WRF) model using multi-cycle 3-dimensional varia-tional data assimilation (3DVAR). Due to the large-scale special topography of the QXP and its sur-rounding areas which may reach up to the mid-troposphere, the AWS located at different height on the deep slope of the plateau are different to those located on plains and take e role analogous in some extent to that of radio soundings in obtaining the vertical "profile" information of the atmosphere, and have the advantages in the aspects of sampling frequency, location/height fixing, and synchronization. The information captured by these AWS may carry the early-warning "strong signals" in the upstream sensitive area for the downstream weather systems to the east of the plateau and thus the assimilation of these AWS data is expected to lead to significant improvements on the simulation of the severe weather system occurred in its downstream areas through adjusting the 3-dimensional structures of the atmospheric thermal-dynamics for the initial conditions of the model. This study indicates that the assimilated information of moisture, temperature and pressure carried in the observations of AWS over the Qinghai-Xizang Plateau and its surrounding areas is very important and useful in the forecasting of precipitation in its downstream areas.

  17. Effect of Amount of Carbon on the Reduction Efficiency of Iron Ore-Coal Composite Pellets in Multi-layer Bed Rotary Hearth Furnace (RHF)

    Science.gov (United States)

    Mishra, Srinibash; Roy, Gour Gopal

    2016-08-01

    The effect of carbon-to-hematite molar ratio has been studied on the reduction efficiency of iron ore-coal composite pellet reduced at 1523 K (1250 °C) for 20 minutes in a laboratory scale multi-layer bed rotary hearth furnace (RHF). Reduced pellets have been characterized through weight loss measurement, estimation of porosity, shrinkage, qualitative and quantitative phase analysis by XRD. Performance parameters such as the degree of reduction, metallization, carbon efficiency, productivity, and compressive strength have been calculated to compare the process efficacy at different carbon levels in the pellets. Pellets with optimum carbon-to-hematite ratio (C/Fe2O3 molar ratio = 1.66) that is much below the stoichiometric carbon required for direct reduction of hematite yielded maximum reduction, better carbon utilization, and productivity for all three layers. Top layer exhibited maximum reduction at comparatively lower carbon level (C/Fe2O3 molar ratio 2.33). Correlation between degree of reduction and metallization indicated non-isothermal kinetics influenced by heat and mass transfer in multi-layer bed RHF. Compressive strength of the partially reduced pellet with optimum carbon content (C/Fe2O3 molar ratio = 1.66) showed that they could be potentially used as an alternate feed in a blast furnace or any other smelting reactor.

  18. Effect of process temperature on morphology of CNTs grown in a vertically fluidized bed reactor with Fe2O3/Al2O3 catalyst

    International Nuclear Information System (INIS)

    Carbon nanotubes (CNTs) are one of the most researched materials due to their exceptional mechanical and electrical properties. Among the various techniques, catalytic chemical vapor deposition in a fluidized bed reactor is the most promising technique for bulk production of CNTs. To meet the demand of good quality along with the bulk production of CNTs, the effect of reaction temperature on the micro structures, morphology, diameter, quality and quantity of CNTs was investigated in these studies. CNTs were synthesized at process temperature ranging from 700-850°C by catalytic decomposition of C2H4 on Fe2O3/Al2O3 catalyst a vertical fluidized bed reactor. The microstructures of the grown CNTs at different reaction temperatures were investigated by using scanning electron microscope. The results of this study depicted a positive correlation between the average diameter of CNTs and reaction temperature. Narrow diameters (35∼40 nm) of CNTs with fewer defects were found at the low and mild temperatures, in particular 800°C. At this temperature, a dynamic equilibrium between the rate of C2H4 decomposition and CNTs quantity was found due to maximum carbon diffusion over catalyst. The CNTs produced with Fe2O3/Al2O3 catalyst wer e also exhibiting high quality with relatively small mean outer diameter and fewer surface defects

  19. Effect of Amount of Carbon on the Reduction Efficiency of Iron Ore-Coal Composite Pellets in Multi-layer Bed Rotary Hearth Furnace (RHF)

    Science.gov (United States)

    Mishra, Srinibash; Roy, Gour Gopal

    2016-04-01

    The effect of carbon-to-hematite molar ratio has been studied on the reduction efficiency of iron ore-coal composite pellet reduced at 1523 K (1250 °C) for 20 minutes in a laboratory scale multi-layer bed rotary hearth furnace (RHF). Reduced pellets have been characterized through weight loss measurement, estimation of porosity, shrinkage, qualitative and quantitative phase analysis by XRD. Performance parameters such as the degree of reduction, metallization, carbon efficiency, productivity, and compressive strength have been calculated to compare the process efficacy at different carbon levels in the pellets. Pellets with optimum carbon-to-hematite ratio (C/Fe2O3 molar ratio = 1.66) that is much below the stoichiometric carbon required for direct reduction of hematite yielded maximum reduction, better carbon utilization, and productivity for all three layers. Top layer exhibited maximum reduction at comparatively lower carbon level (C/Fe2O3 molar ratio 2.33). Correlation between degree of reduction and metallization indicated non-isothermal kinetics influenced by heat and mass transfer in multi-layer bed RHF. Compressive strength of the partially reduced pellet with optimum carbon content (C/Fe2O3 molar ratio = 1.66) showed that they could be potentially used as an alternate feed in a blast furnace or any other smelting reactor.

  20. Special topics reports for the reference tandem mirror fusion breeder: liquid metal MHD pressure drop effects in the packed bed blanket. Vol. 1

    International Nuclear Information System (INIS)

    Magnetohydrodynamic (MHD) effects which result from the use of liquid metal coolants in magnetic fusion reactors include the modification of flow profiles (including the suppression of turbulence) and increases in the primary loop pressure drop and the hydrostatic pressure at the first wall of the blanket. In the reference fission-suppressed tandem mirror fusion breeder design concept, flow profile modification is a relatively minor concern, but the MHD pressure drop in flowing the liquid lithium coolant through an annular packed bed of beryllium/thorium pebbles is directly related to the required first wall structure thickness. As such, it is a major concern which directly impacts fissile breeding efficiency. Consequently, an improved model for the packed bed pressure drop has been developed. By considering spacial averages of electric fields, currents, and fluid flow velocities the general equations have been reduced to simple expressions for the pressure drop. The averaging approach results in expressions for the pressure drop involving a constant which reflects details of the flow around the pebbles. Such details are difficult to assess analytically, and the constant may eventually have to be evaluated by experiment. However, an energy approach has been used in this study to bound the possible values of the constant, and thus the pressure drop. In anticipation that an experimental facility might be established to evaluate the undetermined constant as well as to address other uncertainties, a survey of existing facilities is presented

  1. Transport and Aggregation of Nanoparticles in Packed Beds: Effects of Pore Velocity and Initially-Fed Particle Size on Transient Particle Size Distributions

    Science.gov (United States)

    Pham, Ngoc; Papavassiliou, Dimitrios

    2015-11-01

    Aggregation of colloidal particles in flow through porous media has received careful consideration, as it reduces particle breakthrough due to pore clogging and sedimentation. Additionally, in unstable colloidal systems, deposition of colloidal aggregates on the pore surfaces can create sub-surfaces for further colloidal attachment. This phenomenon is known as ripening effect. In this study, transient particle size distributions of nano-particle systems, propagating in a bed packed with spheres are numerically investigated. In our simulation, only pair interactions are considered, and the aggregation rate is varied with the relative position of two particles in a pair. The packed bed consists of spheres of known size, randomly packed in a simulation box. To generate the velocity field of water inside the porous medium, the lattice Boltzmann method (LBM) is used. In conjunction with that, the trajectories of thousands of massless particles moving with the flow under convection and diffusion are recorded employing a Lagrangian framework. While pore clogging is neglected, we draw attention to the change of the distribution of particle size under different pore velocities and different initially-fed particle sizes.

  2. In-Place Randomized Slope Selection

    DEFF Research Database (Denmark)

    Blunck, Henrik; Vahrenhold, Jan

    2006-01-01

    Slope selection, i.e. selecting the slope with rank k among all 􀀀n 2lines induced by a collection P of points, results in a widely used robust estimator for linefitting. In this paper, we demonstrate that it is possible to perform slope selection in expected O(n·log2 n) time using only c...

  3. Laser powder-bed fusion additive manufacturing: Effects of main physical processes on dynamical melt flow and pore formation from mesoscopic powder simulation

    CERN Document Server

    Khairallah, Saad A; Rubenchik, Alexander

    2015-01-01

    There is a need in laser powder-bed fusion of metals to produce high quality parts without pores by better understanding the complex interplay of process parameters. This study considers the main physical phenomena involved in laser powder interactions using a high fidelity three-dimensional mesoscopic simulation model of 316L stainless steel powder. The model emphasizes the importance of the recoil pressure and the Marangoni effect in generating strong dynamical melt flow and the role of radiative and evaporative cooling at capping the maximum surface temperature. The melt track is divided into an indentation, transition and tail end regions, each being the stage of specific physical effects. Pore formation mechanisms are observed at the edge of a scan track, at the melt pool bottom center during collapse of the indentation, and at the end of the melt track during laser power ramp down. Remedies to these undesirable pores are discussed.

  4. The Influence of Increasing Rain and Earthquake Activities on Landslide Slope Stability in Forest Areas

    Science.gov (United States)

    Kubota, T.; Aditian, A.

    2014-12-01

    Deriving the analysis of rainfall data in various mountainous locations, increase in rainfall that is deemed to be induced by the global climate change is obvious in Kyushu district, western Japan. On this point of view, its long term impact on the forest slope stability is analyzed with field investigation and numerical simulation such as finite element method (FEM). On the other hand, the influence of earthquake such as cracks on the slope due to seismic vibration was also analyzed with FEM. In this case, the slope stability analysis to obtain the factor of safety "Fs" is conducted. Here, in case of the Fs > 1.0, the slope is stable. In addition, the slope stabilizing effect of the forest mainly due to the roots strength is evaluated on some unstable slopes. Simultaneously, a holistic estimation over landslide groups is conducted by comparing "Fs" on forest slopes with non- forest slopes. Therefore, the following conclusions are obtained: 1) Comparing the Fs without increased rainfall from the previous decade and the one with actual rainfall, the former case is 1.04 ~1.06 times more stable than the latter. 2) On the other hand, the forest slopes are estimated to be up to approximately 1.5 to 2.5 times more stable than the slope without forest. Therefore, the slope stabilizing effect by the forest is much higher than the increasing rainfall influence i.e. the climate change effect. These results imply that an appropriate forest existence is important under the climate change condition to prevent forest slope degradation. 3) Comparing with the destabilization of the slope by seismic activities (vibration) due to the reduction of soil strength and "cracks = slope deformation" (8~9 % to 30% reduction in Fs even after an earthquake of 490gal), the influence of the long term rainfall increase on slopes (such as 1% decrease in Fs) is relatively small in the study area.

  5. Geochemical Effects of Induced Stream-Water and Artificial Recharge on the Equus Beds Aquifer, South-Central Kansas, 1995-2004

    Science.gov (United States)

    Schmidt, Heather C. Ross; Ziegler, Andrew C.; Parkhurst, David L.

    2007-01-01

    Artificial recharge of the Equus Beds aquifer is part of a strategy implemented by the city of Wichita, Kansas, to preserve future water supply and address declining water levels in the aquifer of as much as 30 feet caused by withdrawals for water supply and irrigation since the 1940s. Water-level declines represent a diminished water supply and also may accelerate migration of saltwater from the Burrton oil field to the northwest and the Arkansas River to the southwest into the freshwater of the Equus Beds aquifer. Artificial recharge, as a part of the Equus Beds Ground-Water Recharge Project, involves capturing flows larger than base flow from the Little Arkansas River and recharging the water to the Equus Beds aquifer by means of infiltration or injection. The geochemical effects on the Equus Beds aquifer of induced stream-water and artificial recharge at the Halstead and Sedgwick sites were determined through collection and analysis of hydrologic and water-quality data and the application of statistical, mixing, flow and solute-transport, and geochemical model simulations. Chloride and atrazine concentrations in the Little Arkansas River and arsenic concentrations in ground water at the Halstead recharge site frequently exceeded regulatory criteria. During 30 percent of the time from 1999 through 2004, continuous estimated chloride concentrations in the Little Arkansas River at Highway 50 near Halstead exceeded the Secondary Drinking-Water Regulation of 250 milligrams per liter established by the U.S. Environmental Protection Agency. Chloride concentrations in shallow monitoring wells located adjacent to the stream exceeded the drinking-water criterion five times from 1995 through 2004. Atrazine concentrations in water sampled from the Little Arkansas River had large variability and were at or near the drinking-water Maximum Contaminant Level of 3.0 micrograms per liter as an annual average established by the U.S. Environmental Protection Agency. Atrazine

  6. Solids mixing in spouted beds

    OpenAIRE

    Cook, H. H.; Bridgwater, J.; Professor J. Bridgwater

    1981-01-01

    Many industrial processes require contact between particles and a fluid or spray in order to effect drying, coating or granulation. One device capable of contacting fluid and particles efficiently is a spouted bed in which a jet of fluid is injected into solid particles. This forms an open channel or spout and induces material circulation in a downward moving annulus. For the continuous throughput of solids, knowledge is required of the mixing and particle motions within th...

  7. Optimizing aeration rates for minimizing membrane fouling and its effect on sludge characteristics in a moving bed membrane bioreactor

    International Nuclear Information System (INIS)

    Research highlights: → There is an optimum aeration rate in the MBMBR process compartments. → Optimum aeration rate maximizes nutrients removal. → Optimum aeration rate minimizes membrane fouling. → Both aeration rates in MBBR and membrane compartment can affect on membrane permeability. - Abstract: In MBR processes, sufficient aeration is necessary to maintain sustainable flux and to retard membrane fouling. Membrane permeability, sludge characteristics, nutrient removal and biomass growth at various air flow rates in the membrane and moving bed biofilm reactor (MBBR) compartments were studied in a pilot plant. The highest nitrogen and phosphorous removal rates were found at MBBR aeration rates of 151 and 85 L h-1 and a specific aeration demand per membrane area (SADm) of 1.2 and 0.4mair3 m-2 h-1, respectively. A linear correlation was found between the amount of attached biofilm and the nutrient removal rate. The aeration rate in the MBBR compartment and SADm significantly influenced the sludge characteristics and membrane permeability. The optimum combination of the aeration rate in the MBBR compartment and SADm were 151 L h-1 and 0.8-1.2mair3mmembrane-2 h-1, respectively.

  8. Unilateral lower limb suspension does not mimic bed rest or spaceflight effects on human muscle fiber function

    Science.gov (United States)

    Widrick, J. J.; Trappe, S. W.; Romatowski, J. G.; Riley, D. A.; Costill, D. L.; Fitts, R. H.

    2002-01-01

    We used Ca2+-activated skinned muscle fibers to test the hypothesis that unilateral lower leg suspension (ULLS) alters cross-bridge mechanisms of muscle contraction. Soleus and gastrocnemius biopsies were obtained from eight subjects before ULLS, immediately after 12 days of ULLS (post-0 h), and after 6 h of reambulation (post-6 h). Post-0 h soleus fibers expressing type I myosin heavy chain (MHC) showed significant reductions in diameter, absolute and specific peak Ca2+-activated force, unloaded shortening velocity, and absolute and normalized peak power. Fibers obtained from the gastrocnemius were less affected by ULLS, particularly fibers expressing fast MHC isoforms. Post-6 h soleus fibers produced less absolute and specific peak force than did post-0 h fibers, suggesting that reambulation after ULLS induced cell damage. Like bed rest and spaceflight, ULLS primarily affects soleus over gastrocnemius fibers. However, in contrast to these other models, slow soleus fibers obtained after ULLS showed a decrease in unloaded shortening velocity and a greater reduction in specific force.

  9. Resonance effects on the dynamics of dense granular beds: achieving optimal energy transfer in vibrated granular systems

    International Nuclear Information System (INIS)

    Using a combination of experimental techniques and discrete particle method simulations, we investigate the resonant behaviour of a dense, vibrated granular system. We demonstrate that a bed of particles driven by a vibrating plate may exhibit marked differences in its internal energy dependent on the specific frequency at which it is driven, even if the energy corresponding to the oscillations driving the system is held constant and the acceleration provided by the base remains consistently significantly higher than the gravitational acceleration, g. We show that these differences in the efficiency of energy transfer to the granular system can be explained by the existence of resonances between the bed’s bulk motion and that of the oscillating plate driving the system. We systematically study the dependency of the observed resonant behaviour on the system’s main, controllable parameters and, based on the results obtained, propose a simple empirical model capable of determining, for a given system, the points in parameter space for which optimal energy transfer may be achieved. (paper)

  10. Enuresis (Bed-Wetting)

    Science.gov (United States)

    ... get out of bed to go to the bathroom. When do most children achieve bladder control? Children ... ask questions about your child's daytime and nighttime bathroom habits. Then your doctor will do a physical ...

  11. Particle fuel bed tests

    International Nuclear Information System (INIS)

    Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H2 for 12 hours with no visible reaction or weight loss

  12. Tapered bed bioreactor

    Science.gov (United States)

    Scott, Charles D.; Hancher, Charles W.

    1977-01-01

    A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

  13. Impacts of Habitat Slope on Plant from of Astracantha adscendens

    Directory of Open Access Journals (Sweden)

    S.J. Khajeddin

    2001-01-01

    Full Text Available Astracantha adscendens is an endemic species in Iran growing on alpine and above alpine timberline habitats on the Zagross Mountain Range. These habitats are characterized by steep slopes, heavy snowfalls and long ice formation periods. The present study was carried out in Chelgerd, Bakhtiari, and Fereidan, Isfahan. Slopes, elevation above sea-level, and magnetic north azimuth were measured. The canopy cover was also measured along four radii in upward, downward, left and right directions. Regression analysis was performed for the measured values of plant and environmental factors. The results revealed that the upward radius had a high negative correlation with slope changes while the downward radius showed no relationship with slope variations. The two left and right radii had a high and positive relationship with each other, both reducing in length as the slope steepness increased. Shrub volume decreases with increasing slope steepness. Plant shape was classified into seven groups using Sorenson similarity index and constructing the dendrogram. Snow pressure bends the stem toward the soil surface. Snow gliding pressure scratches stem and its base buds above the bent stem. Soil and debris move downward the slope as a result of snow gliding and rainfall runoff as well as wildlife and domestic animals. Snow gliding along with other natural factors have various effects on A. adscendens plant form which can be grouped under three categories: direct mechanical effect of snow, physiological effect of snow, and indirect effect of precipitation and wildlife. The environmental factors and plant physiological responses to them change the A. adscendens plant form from a funnel or ob-conical shape to a semi-funnel or semi ob-conical form.

  14. Research on the Slope Protection Mechanism of Roots

    Directory of Open Access Journals (Sweden)

    Juan Wan

    2013-08-01

    Full Text Available This study aims to investigate the slope protection mechanism of roots. In ecological slope protection, plant roots can fix soil and protect slop through biological and mechanical action. However, previous studies on the slope protection mechanism are still not deep enough and inadequate. By taking four kinds of typical plant roots along Wu-Shen Expressway as the research object, through the indoor tensile test and root morphology observation analysis, the tensile strength and ultimate tension were studied and the influence to the stability of the slope was discussed in this study. The results show that the mean ultimate tension of roots is 7.19~29.96 N. The mean tension of shrub roots is 2~4 times greater than that of herb roots. The ultimate tension of the same plant roots increases with the diameter significantly. To the range of improvement, Shrub roots exceed herb ones. It also indicates that the mean tensile strength of roots are 24.48~74.25 MPa. Compared with the steel HRB235, the tensile strength of herb roots is as great as 1/5~1/3, while Shrub roots is about 1/10~1/5. The slope stability coefficient with plant growing is a positive correlation with roots tension and root number through the sliding surface and is a negative correlation with plants weight. In addition, the slope stability coefficient is related to plant density and root morphology. The test results demonstrate that the roots tension with acute angle or right angle to the landslide surface and the roots shear stiffness with obtuse angle can improve the performance of slope’s anti-slide. Four kinds of plants can improve the stability coefficient of shallow soil. As for the slope protection effect, herbage is superior to shrub. In general, grass-shrub mixed community is the ideal system for slope protection.

  15. Effects of operating conditions and fuel properties on emission performance and combustion efficiency of a swirling fluidized-bed combustor fired with a biomass fuel

    International Nuclear Information System (INIS)

    This work reports an experimental study on firing 80 kg/h rice husk in a swirling fluidized-bed combustor (SFBC) using an annular air distributor as the swirl generator. Two NOx emission control techniques were investigated in this work: (1) air staging of the combustion process, and (2) firing rice husk as moisturized fuel. In the first test series for the air-staged combustion, CO, NO and CxHy emissions and combustion efficiency were determined for burning 'as-received' rice husk at fixed excess air of 40%, while secondary-to-primary air ratio (SA/PA) was ranged from 0.26 to 0.75. The effects of SA/PA on CO and NO emissions from the combustor were found to be quite weak, whereas CxHy emissions exhibited an apparent influence of air staging. In the second test series, rice husks with the fuel-moisture content of 8.4% to 35% were fired at excess air varied from 20% to 80%, while the flow rate of secondary air was fixed. Radial and axial temperature and gas concentration (O2, CO, NO) profiles in the reactor, as well as CO and NO emissions, are discussed for the selected operating conditions. The temperature and gas concentration profiles for variable fuel quality exhibited significant effects of both fuel-moisture and excess air. As revealed by experimental results, the emission of NO from this SFBC can be substantially reduced through moisturizing rice husk, while CO is effectively mitigated by injection of secondary air into the bed splash zone, resulting in a rather low emission of CO and high (over 99%) combustion efficiency of the combustor for the ranges of operating conditions and fuel properties.

  16. The Influence of Shales on Slope Instability

    Science.gov (United States)

    Stead, Doug

    2016-02-01

    Shales play a major role in the stability of slopes, both natural and engineered. This paper attempts to provide a review of the state-of-the-art in shale slope stability. The complexities of shale terminology and classification are first reviewed followed by a brief discussion of the important physical and mechanical properties of relevance to shale slope stability. The varied mechanisms of shale slope stability are outlined and their importance highlighted by reference to international shale slope failures. Stability analysis and modelling of anisotropic rock slope masses are briefly discussed and the potential role of brittle rock fracture and damage highlighted. A short review of shale slopes in open pits is presented.

  17. Improvement of Combustion Characteristics in Fluidized Bed

    International Nuclear Information System (INIS)

    The present investigation is directed towards the experimental study of the effect of a new design of the bed temperature on the overall thermal efficiency and heat transfer by conduction, convection and radiation in gaseous fuel-fluidized bed combustion system. The experiments are performed on a water-cooled fluidized bed model furnace with cylindrical cross-section of 0.25 m diameter and its height is 0.60 m. the fluidising medium used is sand particles with average diameter 1.5 mm. The bed temperature is varied between 700 degree C and 1100 degree C. Measurements f carbon dioxide, carbon monoxide and oxygen concentrations are carried out by using water-cooled sampling probe, and infrared and paramagnetic analyzers. The results obtained show that the bed temperature, the total heat transfer to the wall and the bed combustion efficiency increase with the decrease of the air-fuel ratio. It is also found that 91% of the total heat transfer is in the fluidising part of the bed and most of this heat is transferred by convection from hot sand particles to the wall. Two empirical formulae for the calculation of the wall heat transfer coefficient and the particle convective heat transfer coefficient are proposed. A verification of the proposed empirical formulae is made by comparing the calculated values with the experimental results.

  18. On the role of topographic amplification in seismic slope instabilities

    Directory of Open Access Journals (Sweden)

    Fardin Jafarzadeh

    2015-04-01

    Full Text Available Surface wave generation due to body wave propagation near ground surface has been discussed in the literature. This phenomenon, typically occurring in topographic changing areas, along with its interaction with body waves (SV, decreases precision of formulas for evaluation of slope displacement. This significant fact caused the researchers not only to investigate the combined surface and SV waves motion pattern, but also to consider its effect on structures built on the slopes. In order to reveal the phenomenon, several finite element numerical studies have been performed by ABAQUS programme. Besides, two physical model slopes simulating the landslide occurrence have been constructed and tested by shaking table device. The results of induced and calculated accelerations obtained by two approaches have been compared and Rayleigh wave generation has been proved. Furthermore, the slope displacements have been calculated by various empirical methods and the results were compared with numerical ones. The results proved that in order to increase the precision of empirical formulas for displacement prediction, surface wave effect should be taken into account. Finally, a concept of “effective depth of surficial amplification” is introduced and its effect on dynamic slope stability is analysed.

  19. Effect of nutrient enrichment on the source and composition of sediment organic carbon in tropical seagrass beds in the South China Sea.

    Science.gov (United States)

    Liu, Songlin; Jiang, Zhijian; Zhang, Jingping; Wu, Yunchao; Lian, Zhonglian; Huang, Xiaoping

    2016-09-15

    To assess the effect of nutrient enrichment on the source and composition of sediment organic carbon (SOC) beneath Thalassia hemprichii and Enhalus acoroides in tropical seagrass beds, Xincun Bay, South China Sea, intertidal sediment, primary producers, and seawater samples were collected. No significant differences on sediment δ(13)C, SOC, and microbial biomass carbon (MBC) were observed between T. hemprichii and E. acoroides. SOC was mainly of autochthonous origin, while the contribution of seagrass to SOC was less than that of suspended particulate organic matter, macroalgae and epiphytes. High nutrient concentrations contributed substantially to SOC of seagrass, macroalgae, and epiphytes. The SOC, MBC, and MBC/SOC ratio in the nearest transect to fish farming were the highest. This suggested a more labile composition of SOC and shorter turnover times in higher nutrient regions. Therefore, the research indicates that nutrient enrichment could enhance plant-derived contributions to SOC and microbial use efficiency. PMID:27334726

  20. Better backs by better beds?

    DEFF Research Database (Denmark)

    Bergholdt, Kim; Fabricius, Rasmus N; Bendix, Tom

    2008-01-01

    STUDY DESIGN: A "randomized"/stratified, single-blinded, parallel-group study. OBJECTIVE.: To evaluate 3 structurally different mattresses relative influence on patients with chronic low back pain (CLBP). SUMMARY OF BACKGROUND DATA: In several advertisements, it is proclaimed that certain......-conforming foam mattress (Tempur), and (3) a hard mattress (Innovation Futon). At baseline and after 4 weeks, a blinded observer interviewed the patients on LBP levels (0-10), daily function (activities of daily living, 0-30), and on the amount of sleeping hours/night. RESULTS: Because of dropout of 19 patients...... using the probably most relevant "worst case" data. There were no relevant difference between the effects of the water bed and the foam bed. CONCLUSION: The Waterbed and foam mattress' did influence back symptoms, function and sleep more positively as apposed to the hard mattress, but the differences...

  1. PlanHab: the combined and separate effects of 16 days of bed rest and normobaric hypoxic confinement on circulating lipids and indices of insulin sensitivity in healthy men.

    Science.gov (United States)

    Simpson, Elizabeth J; Debevec, Tadej; Eiken, Ola; Mekjavic, Igor; Macdonald, Ian A

    2016-04-15

    PlanHab is a planetary habitat simulation study. The atmosphere within future space habitats is anticipated to have reduced Po2, but information is scarce as to how physiological systems may respond to combined exposure to moderate hypoxia and reduced gravity. This study investigated, using a randomized-crossover design, how insulin sensitivity, glucose tolerance, and circulating lipids were affected by 16 days of horizontal bed rest in normobaric normoxia [NBR: FiO2 = 0.209; PiO2 = 133.1 (0.3) mmHg], horizontal bed rest in normobaric hypoxia [HBR: FiO2 = 0.141 (0.004); PiO2 = 90.0 (0.4) mmHg], and confinement in normobaric hypoxia combined with daily moderate intensity exercise (HAMB). A mixed-meal tolerance test, with arterialized-venous blood sampling, was performed in 11 healthy, nonobese men (25-45 yr) before (V1) and on the morning ofday 17of each intervention (V2). Postprandial glucose and c-peptide response were increased at V2 of both bed rest interventions (PHypoxia did not alter the adverse effects of bed rest on insulin sensitivity and glucose tolerance but appeared to increase insulin clearance. The negative effect of bed rest on HDL was compounded in hypoxia, which may have implications for long-term health of those living in future space habitats. PMID:26769956

  2. The Effect of Biogeochemical and Hydrologic Processes on Nitrogen in Stream Water Originating From Coal-Bed Methane Supply Wells

    Science.gov (United States)

    Smith, R. L.; Repert, D. A.; Hart, C. P.

    2003-12-01

    Water obtained from coal-bed methane (CBM) wells typically contains a variety of reduced chemical constituents, including methane, metal ions, particulate and dissolved organic carbon, and ammonium. In many locales in Wyoming and Montana, CBM water is disposed via discharge to stream channels and reservoirs. Though it is likely that biogeochemical and hydrologic processes will result in major changes in the chemical composition of these waters with subsequent downstream transport, few studies have actually examined these water quality changes or their ecological impacts. A field study was conducted in the Powder River Basin, WY to document changes in solute composition within stream channels below discharge points of CBM water. Particular emphasis was placed on nitrogen and nitrogen cycling processes. Concentration ranges in discharge water were: DOC, 200-350 μ M; alkalinity, 40-50 meq/L; specific conductance, 3.3-4.0 mS/cm; ammonium, 350-400 μ M; and pH, 7.2-7.3. Ammonium concentrations decreased with transport distance via nitrification, with subsequent increases in nitrite and nitrate. Within a single discharge channel, nitrite concentrations increased with travel distance, peaking at >100 μ M at 100-200 m, but also exhibited a strong diel pattern that was inversely related to incident light. Nitrite production/consumption processes differed significantly within in-stream incubation chambers, depending upon location relative to the CBM discharge point and time of day. In the main channel, subject to several CBM discharge points, diel nitrite concentrations were more constant at a fixed station, but did increase with distance downstream. Main channel total inorganic nitrogen remained relatively constant ( ˜400 μ M N) with distance (>5 km), suggesting little net nitrogen removal. The results of this study suggest that CBM discharge can serve as a significant source of dissolved nitrogen to western watersheds, with oxidative processes resulting in nitrate and

  3. Foam drainage on a sloping weir.

    Science.gov (United States)

    Grassia, P; Neethling, S J; Cilliers, J J

    2002-08-01

    Foam drainage is considered in a froth flotation tank with a sloping weir. The drainage is shown to be gravity dominated in most of the foam, except for thin boundary layers at the base of the froth, and along the sloping weir. The mathematical reason for the boundary layers is that capillary suction is a much weaker effect than gravity, but cannot be ignored altogether, because it represents a singular perturbation. The relative weakness of capillary suction with respect to gravity is represented by a key dimensionless parameter, denoted K, which satisfies Kbulk of the flotation tank. The liquid volume fraction in the jet is likewise O(K(-2/3)) larger than that in the bulk. Across the jet, the foam exhibits a known profile of liquid fraction vs. distance from the weir: this is known as the equilibrium profile. The foam requires a distance equivalent to O(K(4/3)) weir lengths to dry out significantly from the wetness value on the weir, but a larger O(K) distance to fall back to a wetness comparable with that in the bulk of the froth. PMID:15015124

  4. Sub-kT/q subthreshold slope p-metal-oxide-semiconductor field-effect transistors with single-grained Pb(Zr,Ti)O3 featuring a highly reliable negative capacitance

    Science.gov (United States)

    Park, Jae Hyo; Joo, Seung Ki

    2016-03-01

    A reliable on/off switching with an sub-kT/q subthreshold slope (38 mV/dec at room temperature) is experimentally demonstrated with using selectively nucleated laterally crystallized single-grain Pb(Zr,Ti)O3 (PZT) ferroelectric and ZrTiO4 paraelectric thin-film. The combination of ferroelectric and paraelectric thin-film is enabled to form a negative capacitance (NC) at the weak inversion region. However, the PZT grain-boundary easily degrades the NC properties after switching the on/off more than 108 times. It is found that the polarization of PZT is diminished from the path of grain-boundary. Here, we effectively suppress the degradation of NC MOS-FET which did not showed any fatigue even after 108 on/off switching.

  5. The Socioeconomic Assessment of Sloping Land Conversion Program in China

    DEFF Research Database (Denmark)

    Liu, Zhen

    Abstract This thesis mainly focuses on the socioeconomic impact of the largest Ecological Recovery Program ― the Sloping Land Conversion Program (SLCP), also called Grain for Green Program (GFG) in China. The central government initiated this program in 1999 and it was launched nationwide in 2002...... amount of household survey data, this study aims to improve our understanding of the treatment effect of the SLCP on farm households, which is split into three parts. The first paper ― The Sloping Land Conversion Program in China: Effects on Rural Households’ Livelihood Diversification, evaluates the...... effects of the implementation of the Sloping Land Conversion Program (SLCP) on livelihood diversification, which is thought to be the solution to poverty and environmental dilemmas. Our results show that SLCP works as a valid external policy intervention on rural livelihood diversification. In addition...

  6. A study on dynamic response of slopes under wave action using simulation tests

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    After the erection of the Three Gorges Dam, the water level of Yangtze River will reach 175 m, and the average wave crest will be up to 1 m. Therefore the wave action cannot be neglected for the slope stability. Through simulation tests, the waveinduced dynamic response of the slope is analyzed. The soil body is taken as linear elastic body when it has a small deformation under the small wave action. Based on tests, the excess pore pressure and slope displacement under the loading in different wave period are analyzed. The ratio of dynamic strength and static strength to the breaking process of the slope is discussed. It is demonstrated that smaller wave period gives rise to a larger strain of the slope under the same stress. At different depth of water, different weakness effect on the stability of the soil slope is observed and the slope has an adaptability to the wave action to some extent.

  7. Relative Biologic Effectiveness (RBE) of 50 kV X-rays Measured in a Phantom for Intraoperative Tumor-Bed Irradiation

    International Nuclear Information System (INIS)

    Purpose: Intraoperative radiation therapy (IORT) with low-energy x-rays is used to treat the tumor bed during breast-conserving surgery. The purpose was to determine the relative biologic effectiveness (RBE) of 50-kV x-rays for inactivation of cells irradiated in a tumor-bed phantom. Methods and Materials: The RBE was determined for clonogenic inactivation of human tumor and normal cells (MCF7, human umbilical vein endothelial cells, normal skin fibroblasts), and hamster V79 cells. The 50-kV x-rays from the Intrabeam machine (Carl Zeiss Surgical) with a spherical 4-cm applicator were used. Cells were irradiated in a water-equivalent phantom at defined distances (8.1-22.9 mm) from the applicator surface. The 50-kV x-rays from a surface therapy machine (Dermopan, Siemens) were included for comparison; 6-MV x-rays were used as reference radiation. Results: At 8.1-mm depth in the phantom (dose rate 15.1 Gy/h), mean RBE values of 50-kV x-rays from Intrabeam were 1.26 to 1.42 for the 4 cell types at doses yielding surviving fractions in the range of 0.01 to 0.5. Confidence intervals were in the range of 1.2 and 1.5. Similar RBE values were found for 50-kV x-rays from Dermopan for V79 (1.30, CI 1.25-1.36, P=.74) and GS4 (1.42, CI 1.30-1.54, P=.67). No significant dependence of RBE on dose was found for Intrabeam, but RBE decreased at a larger distance (12.7 mm; 9.8 Gy/h). Conclusions: An increased clinically relevant RBE was found for cell irradiation with Intrabeam at depths in the tumor bed targeted by IORT. The reduced RBE values at larger distances may be related to increased repair of sublethal damage during protracted irradiation or to hardening of the photon beam energy

  8. Relative Biologic Effectiveness (RBE) of 50 kV X-rays Measured in a Phantom for Intraoperative Tumor-Bed Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qi; Schneider, Frank; Ma, Lin; Wenz, Frederik [Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim (Germany); Herskind, Carsten, E-mail: carsten.herskind@medma.uni-heidelberg.de [Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim (Germany)

    2013-03-15

    Purpose: Intraoperative radiation therapy (IORT) with low-energy x-rays is used to treat the tumor bed during breast-conserving surgery. The purpose was to determine the relative biologic effectiveness (RBE) of 50-kV x-rays for inactivation of cells irradiated in a tumor-bed phantom. Methods and Materials: The RBE was determined for clonogenic inactivation of human tumor and normal cells (MCF7, human umbilical vein endothelial cells, normal skin fibroblasts), and hamster V79 cells. The 50-kV x-rays from the Intrabeam machine (Carl Zeiss Surgical) with a spherical 4-cm applicator were used. Cells were irradiated in a water-equivalent phantom at defined distances (8.1-22.9 mm) from the applicator surface. The 50-kV x-rays from a surface therapy machine (Dermopan, Siemens) were included for comparison; 6-MV x-rays were used as reference radiation. Results: At 8.1-mm depth in the phantom (dose rate 15.1 Gy/h), mean RBE values of 50-kV x-rays from Intrabeam were 1.26 to 1.42 for the 4 cell types at doses yielding surviving fractions in the range of 0.01 to 0.5. Confidence intervals were in the range of 1.2 and 1.5. Similar RBE values were found for 50-kV x-rays from Dermopan for V79 (1.30, CI 1.25-1.36, P=.74) and GS4 (1.42, CI 1.30-1.54, P=.67). No significant dependence of RBE on dose was found for Intrabeam, but RBE decreased at a larger distance (12.7 mm; 9.8 Gy/h). Conclusions: An increased clinically relevant RBE was found for cell irradiation with Intrabeam at depths in the tumor bed targeted by IORT. The reduced RBE values at larger distances may be related to increased repair of sublethal damage during protracted irradiation or to hardening of the photon beam energy.

  9. Using ground and intact coal Samples to evaluate hydrocarbon fate during supercritical CO2 injection into coal beds: effects of particle size and coal moisture

    Science.gov (United States)

    Kolak, Jon; Hackley, Paul C.; Ruppert, Leslie F.; Warwick, Peter D.; Burruss, Robert

    2015-01-01

    To investigate the potential for mobilizing organic compounds from coal beds during geologic carbon dioxide (CO2) storage (sequestration), a series of solvent extractions using dichloromethane (DCM) and using supercritical CO2 (40 °C and 10 MPa) were conducted on a set of coal samples collected from Louisiana and Ohio. The coal samples studied range in rank from lignite A to high volatile A bituminous, and were characterized using proximate, ultimate, organic petrography, and sorption isotherm analyses. Sorption isotherm analyses of gaseous CO2 and methane show a general increase in gas storage capacity with coal rank, consistent with findings from previous studies. In the solvent extractions, both dry, ground coal samples and moist, intact core plug samples were used to evaluate effects of variations in particle size and moisture content. Samples were spiked with perdeuterated surrogate compounds prior to extraction, and extracts were analyzed via gas chromatography–mass spectrometry. The DCM extracts generally contained the highest concentrations of organic compounds, indicating the existence of additional hydrocarbons within the coal matrix that were not mobilized during supercritical CO2 extractions. Concentrations of aliphatic and aromatic compounds measured in supercritical CO2 extracts of core plug samples generally are lower than concentrations in corresponding extracts of dry, ground coal samples, due to differences in particle size and moisture content. Changes in the amount of extracted compounds and in surrogate recovery measured during consecutive supercritical CO2extractions of core plug samples appear to reflect the transition from a water-wet to a CO2-wet system. Changes in coal core plug mass during supercritical CO2 extraction range from 3.4% to 14%, indicating that a substantial portion of coal moisture is retained in the low-rank coal samples. Moisture retention within core plug samples, especially in low-rank coals, appears to inhibit

  10. Constructing a framework for risk analyses of climate change effects on the water budget of differently sloped vineyards with a numeric simulation using the Monte Carlo method coupled to a water balance model

    Directory of Open Access Journals (Sweden)

    Marco eHofmann

    2014-12-01

    Full Text Available Grapes for wine production are a highly climate sensitive crop and vineyard water budget is a decisive factor in quality formation. In order to conduct risk assessments for climate change effects in viticulture models are needed which can be applied to complete growing regions. We first modified an existing simplified geometric vineyard model of radiation interception and resulting water use to incorporate numerical Monte Carlo simulations and the physical aspects of radiation interactions between canopy and vineyard slope and azimuth. We then used four regional climate models to assess for possible effects on the water budget of selected vineyard sites up 2100. The model was developed to describe the partitioning of short-wave radiation between grapevine canopy and soil surface, respectively green cover, necessary to calculate vineyard evapotranspiration. Soil water storage was allocated to two sub reservoirs. The model was adopted for steep slope vineyards based on coordinate transformation and validated against measurements of grapevine sap flow and soil water content determined down to 1.6 m depth at three different sites over two years. The results showed good agreement of modelled and observed soil water dynamics of vineyards with large variations in site specific soil water holding capacity and viticultural management. Simulated sap flow was in overall good agreement with measured sap flow but site-specific responses of sap flow to potential evapotranspiration were observed. The analyses of climate change impacts on vineyard water budget demonstrated the importance of site-specific assessment due to natural variations in soil water holding capacity. The improved model was capable of describing seasonal and site-specific dynamics in soil water content and could be used in an amended version to estimate changes in the water budget of entire grape growing areas due to evolving climatic changes.

  11. Constructing a framework for risk analyses of climate change effects on the water budget of differently sloped vineyards with a numeric simulation using the Monte Carlo method coupled to a water balance model.

    Science.gov (United States)

    Hofmann, Marco; Lux, Robert; Schultz, Hans R

    2014-01-01

    Grapes for wine production are a highly climate sensitive crop and vineyard water budget is a decisive factor in quality formation. In order to conduct risk assessments for climate change effects in viticulture models are needed which can be applied to complete growing regions. We first modified an existing simplified geometric vineyard model of radiation interception and resulting water use to incorporate numerical Monte Carlo simulations and the physical aspects of radiation interactions between canopy and vineyard slope and azimuth. We then used four regional climate models to assess for possible effects on the water budget of selected vineyard sites up 2100. The model was developed to describe the partitioning of short-wave radiation between grapevine canopy and soil surface, respectively, green cover, necessary to calculate vineyard evapotranspiration. Soil water storage was allocated to two sub reservoirs. The model was adopted for steep slope vineyards based on coordinate transformation and validated against measurements of grapevine sap flow and soil water content determined down to 1.6 m depth at three different sites over 2 years. The results showed good agreement of modeled and observed soil water dynamics of vineyards with large variations in site specific soil water holding capacity (SWC) and viticultural management. Simulated sap flow was in overall good agreement with measured sap flow but site-specific responses of sap flow to potential evapotranspiration were observed. The analyses of climate change impacts on vineyard water budget demonstrated the importance of site-specific assessment due to natural variations in SWC. The improved model was capable of describing seasonal and site-specific dynamics in soil water content and could be used in an amended version to estimate changes in the water budget of entire grape growing areas due to evolving climatic changes. PMID:25540646

  12. The Freeze-thaw Cycling Effects on Slope Stability in Earthquake%冻融循环作用下边坡地震动稳定性研究

    Institute of Scientific and Technical Information of China (English)

    王文丽; 王兰民; 郑龙

    2013-01-01

    In seasonal and permanent permafrost region,the soil mechanical properties may be changed considerably in construction work,which is potentially threat to the stability of infrastructure during earthquakes.This paper develops an analysis platform for the slope earthquake stability considering freeze-thaw cycling based on FLAC.The platform embedded an explicit specific heat algorithm to reflect the ice-water phase change effect.The effects of freeze-thaw cycling on slope earthquake stability are analyzed.The results indicate that the range of active layer is a main factor influencing the plastic destroying form.%季节冻土区和多年冻土区边坡在经历冻融循环后其力学性质产生较大变化,边坡稳定性随之改变,在地震动荷载作用下存在着巨大的安全隐患.本文基于FLAC数值软件,将考虑冻土相变的显热熔算法引入热学计算模块,并结合静态边界动力计算模块,建立了适用于冻融循环条件下的边坡地震动稳定性分析平台.研究了冻融循环对边坡土体地震动稳定性的影响.结果表明,在发生冻融循环的季节冻土区或多年冻土已经退化的区域,地震动后边坡的塑性破坏形式主要取决于发生冻融循环的活动层的范围.

  13. Effect of a disinfectant powder on methicillin-resistant Staphylococcus aureus in pigs, bedding and air samples under simulated farm conditions

    DEFF Research Database (Denmark)

    Gongora, Carmen Espinosa; Damborg, Peter Panduro; Nielsen, Søren Saxmose;

    2013-01-01

    applications of the disinfectant. MRSA load was measured in samples from pigs, bedding material and air and analysed statistically. While pigs remained positive with variable MRSA counts, the amount of MRSA in the air and bedding material increased significantly during the first week and then was gradually...

  14. Comparison of rill flow velocity over frozen and thawed slopes with electrolyte tracer method

    Science.gov (United States)

    Ban, Yunyun; Lei, Tingwu; Liu, Zhiqiang; Chen, Chao

    2016-03-01

    Freeze-thaw erosion is the primary soil water erosion form in high altitude and/or high latitude regions. The water flow velocity along an eroding rill over frozen and thawed slopes is vital to understanding of rill erosion hydrodynamics. This study experimentally measured rill flow velocity over frozen and thawed slopes using electrolyte trace method under Pulse Boundary Model. The experiments used three flow rates of 1, 2, and 4 L min-1, three slope gradients of 5°, 10°, and 15°. The temperature of the rill flow water was supplied at 0 °C as controlled with ice-water mixture. Seven sensors were used to measure flow velocity by tracing the solute transport process at 10, 110, 210, 310, 410, 510, and 610 cm distances from the electrolyte injection position. The measured velocity became steady at a distance of about 3 m from the electrolyte injection location, where the effect of the pulse boundary condition on the analytic solution to the partial differential equation becomes negligible. Results showed that flow velocity increased with slope gradient and flow rate on frozen slopes. A significant effect was observed on the steepest slope or at the highest flow rate over the thawed slope, which changed slightly on the gentle slopes and low flow rates. Flow velocity was about 25%, 30%, and 40% higher on the frozen soil than on the thawed slope at 5°, 10°, and 15° slopes and about 30% higher over the frozen slope at all flow rates. This study demonstrates that water over a frozen slope flows much faster than over a thawed slope. This study helps in the study and further understanding of the hydrodynamics of soil erosion and sediment transport behaviors of frozen and thawed slopes.

  15. The Effect of Sediment Transport and Hydrological Conditions on Wetlands Bed Elevation: A numerical Approach in Loxahatchee Impoundment Landscape Assessment (LILA)

    Science.gov (United States)

    Mahmoudi, M.; Miralles-Wilhelm, F. R.; Garcia, R.

    2012-12-01

    A physically based numerical model of sediment transport has been developed as an extension to FLO - 2D integrated surface water/groundwater model. The developed model has been used to simulate the effect of sediment transport and surface water/groundwater interactions on spatial and temporal variation of bed elevation in the ridge and slough landscape, and to explore how these processes may affect the formation, maintenance and stability of the ridge and slough landscape patterns observed in wetlands. The developed model was calibrated using data obtained from a tracer test study which was conducted in 2007 at Loxahatchee Impoundment Landscape Assessment (LILA). Sensitivity analysis was performed to assess how the model responds to changes in flow conditions and groundwater head elevation. Water samples were taken from several locations within a flowing macrocosm of LILA before, and after extreme events, and during a series of manually generated pulse flow. Suspended sediment concentration was measured in the lab. These data along with other data such as water depth and velocity, and groundwater head, were collected to support and validate the developed model. Bed elevation is been measured using site topography from available LiDAR data. Results from the model development and numerical simulations from this research will provide an improved understanding of how wetland features such as ridges may have formed and degraded by changes in water management that resulted from increasing human activity in wetlands such as The Florida Everglades, over the past decades Ridge and Slough Featurs of The Everglades, Florida Loxahatchee Impoundment Landscape Assessment (LILA), West Palm Beach, Florida

  16. Fluidised bed heat exchangers

    International Nuclear Information System (INIS)

    Problems that have arisen during the initial stages of development of fluidised bed boilers in which heat transfer surfaces are immersed in fluidised solids are discussed. The very high heat transfer coefficients that are obtained under these conditions can be exploited to reduce the total heat transfer surface to a fraction of that in normal boilers. However, with the high heat flux levels involved, tube stressing becomes more important and it is advantageous to use smaller diameter tubes. One of the initial problems was that the pumping power absorbed by the fluidised bed appeared to be high. The relative influence of the fluidising velocity (and the corresponding bed area), tube diameter, tube spacing, heat transfer coefficient and bed temperature on pumping power and overall cost was determined. This showed the importance of close tube packing and research was undertaken to see if this would adversely affect the heat transfer coefficient. Pressure operation also reduces the pumping power. Fouling and corrosion tests in beds burning coal suggest that higher temperatures could be reached reliably and cost studies show that, provided the better refractory metals are used, the cost of achieving higher temperatures is not unduly high. It now remains to demonstrate at large scale that the proposed systems are viable and that the methods incorporated to overcome start up and part lead running problems are satisfactory. The promising role of these heat transfer techniques in other applications is briefly discussed

  17. Simulation of groundwater flow, effects of artificial recharge, and storage volume changes in the Equus Beds aquifer near the city of Wichita, Kansas well field, 1935–2008

    Science.gov (United States)

    Kelly, Brian P.; Pickett, Linda L.; Hansen, Cristi V.; Ziegler, Andrew C.

    2013-01-01

    storage area compared to metered recharge of 1,796 acre-ft indicates some loss of metered recharge. Increased storage outside of the basin storage area of 183 acre-ft accounts for all but 6 acre-ft or 0.33 percent of the total. Previously estimated recharge credits for 2007 and 2008 are 1,018 and 600 acre-ft, respectively, and a total estimated recharge credit of 1,618 acre-ft. Storage changes calculated for this study are 4.42 percent less for 2007 and 5.67 percent more for 2008 than previous estimates. Total storage change for 2007 and 2008 is 0.68 percent less than previous estimates. The small difference between the increase in storage from artificial recharge estimated with the groundwater-flow model and metered recharge indicates the groundwater model correctly accounts for the additional water recharged to the Equus Beds aquifer as part of the Aquifer Storage and Recovery project. Small percent differences between inflows and outflows for all stress periods and all index cells in the basin storage area, improved calibration compared to the previous model, and a reasonable match between simulated and measured long-term base flow indicates the groundwater model accurately simulates groundwater flow in the study area. The change in groundwater level through recent years compared to the August 1940 groundwater level map has been documented and used to assess the change of storage volume of the Equus Beds aquifer in and near the Wichita well field for three different areas. Two methods were used to estimate changes in storage from simulation results using simulated change in groundwater levels in layer 1 between stress periods, and using ZONEBUDGET to calculate the change in storage in the same way the effects of artificial recharge were estimated within the basin storage area. The three methods indicate similar trends although the magnitude of storage changes differ. Information about the change in storage in response to hydrologic stresses is important for managing

  18. Effective rainfall: a significant parameter to improve understanding of deep-seated rainfall triggering landslide – a simple computation temperature based method applied to Séchilienne unstable slope (French Alps

    Directory of Open Access Journals (Sweden)

    A. Vallet

    2013-07-01

    Full Text Available Pore water pressure, build up by recharge of hydrosystems, is one of the main triggering factors of deep seated landslides. Effective rainfall, which is the part of the rainfall which recharges the aquifer, is a significant parameter. Soil-water balance is an accurate way to estimate effective rainfall. Nevertheless this approach requires evapotranspiration, soil water storage and runoff characterization. Available soil storage and runoff were deduced from field observations whereas evapotranspiration computation is a highly demanding method requiring significant input of meteorological data. Most of the landslide sites used weather stations with limited datasets. A workflow method was developed to compute effective rainfall requiring only temperature and rainfall as inputs. Two solar radiation and five commonly used evapotranspiration equations were tested at Séchilienne. The method was developed to be as general as possible in order to be able to be applied to other landslides. This study demonstrated that, for the Séchilienne unstable slope, the displacement data correlation performance (coefficient of determination is significantly enhanced with effective rainfall (0.633 compared to results obtained with raw rainfall (0.436 data. The proposed method for estimation of effective rainfall was developed to be sufficiently simple to be used by any non-hydro specialist who intends to characterize the relationship of rainfall to landslide displacements.

  19. Effective rainfall: a significant parameter to improve understanding of deep-seated rainfall triggering landslide - a simple computation temperature based method applied to Séchilienne unstable slope (French Alps)

    Science.gov (United States)

    Vallet, A.; Bertrand, C.; Mudry, J.

    2013-07-01

    Pore water pressure, build up by recharge of hydrosystems, is one of the main triggering factors of deep seated landslides. Effective rainfall, which is the part of the rainfall which recharges the aquifer, is a significant parameter. Soil-water balance is an accurate way to estimate effective rainfall. Nevertheless this approach requires evapotranspiration, soil water storage and runoff characterization. Available soil storage and runoff were deduced from field observations whereas evapotranspiration computation is a highly demanding method requiring significant input of meteorological data. Most of the landslide sites used weather stations with limited datasets. A workflow method was developed to compute effective rainfall requiring only temperature and rainfall as inputs. Two solar radiation and five commonly used evapotranspiration equations were tested at Séchilienne. The method was developed to be as general as possible in order to be able to be applied to other landslides. This study demonstrated that, for the Séchilienne unstable slope, the displacement data correlation performance (coefficient of determination) is significantly enhanced with effective rainfall (0.633) compared to results obtained with raw rainfall (0.436) data. The proposed method for estimation of effective rainfall was developed to be sufficiently simple to be used by any non-hydro specialist who intends to characterize the relationship of rainfall to landslide displacements.

  20. Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Stynes, J. K.; Ihas, B.

    2012-04-01

    The National Renewable Energy Laboratory (NREL) has developed an optical measurement tool for parabolic solar collectors that measures the combined errors due to absorber misalignment and reflector slope error. The combined absorber alignment and reflector slope errors are measured using a digital camera to photograph the reflected image of the absorber in the collector. Previous work using the image of the reflection of the absorber finds the reflector slope errors from the reflection of the absorber and an independent measurement of the absorber location. The accuracy of the reflector slope error measurement is thus dependent on the accuracy of the absorber location measurement. By measuring the combined reflector-absorber errors, the uncertainty in the absorber location measurement is eliminated. The related performance merit, the intercept factor, depends on the combined effects of the absorber alignment and reflector slope errors. Measuring the combined effect provides a simpler measurement and a more accurate input to the intercept factor estimate. The minimal equipment and setup required for this measurement technique make it ideal for field measurements.