Effects of lowering interior canal stages on salt-water intrusion into the shallow aquifer in Southeast Palm Beach County, Florida

USGS Publications Warehouse

Land, Larry F.

1975-01-01

Land in southeast Palm Beach County is undergoing a large-scale change in use, from agricultural to residential. To accommodate residential use, a proposal has been made by developers to the Board of the Lake Worth Drainage District to lower the canal stages in the interior part of the area undergoing change. This report documents one of the possible effects of such lowering. Of particular interest to the Board was whether the lower canal stages would cause an increase in salt-water intrusion into the shallow aquifer along the coast. The two main tools used in the investigation were a digital model for aquifer evaluation and an analytical technique for predicting the movement of the salt-water front in response to a change of ground-water flow into the ocean. The method of investigation consisted of developing a digital ground-water flow model for three east-west test strips. They pass through the northern half of municipal well fields in Lake Worth, Delray Beach, and Boca Raton. The strips were first modeled with no change in interior canal stages. Then they were modeled with a change in canal stages of 2 to 4 feet (0.6 to 1.6 metres). Also, two land development schemes were tested. One was for a continuation of the present level of land development, simulated by continuing the present pumpage rates. The second scheme was for land development to continue until the maximum allowable densities were reached, simulated by increasing the pumping rates. The results of the test runs for an east-west strip through Lake Worth show that lowering part of the interior canal water levels 3 feet (1.0 metre), as done in 1961, does not affect the aquifer head or salt-water intrusion along the coastal area of Lake Worth. As a result, no effect in the coastal area would be expected as a result of canal stage lowering in other, interior parts of the study area. Results from the other test runs show that lowering interior canal water levels by as much as 4 feet (1.2 metres) would

Experimental saltwater intrusion in coastal aquifers using automated image analysis: Applications to homogeneous aquifers

NASA Astrophysics Data System (ADS)

Robinson, G.; Ahmed, Ashraf A.; Hamill, G. A.

2016-07-01

This paper presents the applications of a novel methodology to quantify saltwater intrusion parameters in laboratory-scale experiments. The methodology uses an automated image analysis procedure, minimising manual inputs and the subsequent systematic errors that can be introduced. This allowed the quantification of the width of the mixing zone which is difficult to measure in experimental methods that are based on visual observations. Glass beads of different grain sizes were tested for both steady-state and transient conditions. The transient results showed good correlation between experimental and numerical intrusion rates. The experimental intrusion rates revealed that the saltwater wedge reached a steady state condition sooner while receding than advancing. The hydrodynamics of the experimental mixing zone exhibited similar traits; a greater increase in the width of the mixing zone was observed in the receding saltwater wedge, which indicates faster fluid velocities and higher dispersion. The angle of intrusion analysis revealed the formation of a volume of diluted saltwater at the toe position when the saltwater wedge is prompted to recede. In addition, results of different physical repeats of the experiment produced an average coefficient of variation less than 0.18 of the measured toe length and width of the mixing zone.

Estimating estuarine salt intrusion using an analytical and a full hydrodynamic simulation - a comparison for the Ma Estuary

NASA Astrophysics Data System (ADS)

Nguyen, Duc Anh; Cat Vu, Minh; Willems, Patrick; Monbaliu, Jaak

2017-04-01

Salt intrusion is the most acute problem for irrigation water quality in coastal regions during dry seasons. The use of numerical hydrodynamic models is widespread and has become the prevailing approach to simulate the salinity distribution in an estuary. Despite its power to estimate both spatial and temporal salinity variations along the estuary, this approach also has its drawbacks. The high computational cost and the need for detailed hydrological, bathymetric and tidal datasets, put some limits on the usability in particular case studies. In poor data environments, analytical salt intrusion models are more widely used as they require less data and have a further reduction of the computational effort. There are few studies however where a more comprehensive comparison is made between the performance of a numerical hydrodynamic and an analytical model. In this research the multi-channel Ma Estuary in Vietnam is considered as a case study. Both the analytical and the hydrodynamic simulation approaches have been applied and were found capable to mimic the longitudinal salt distribution along the estuary. The data to construct the MIKE11 model include observations provided by a network of fixed hydrological stations and the cross-section measurements along the estuary. The analytic model is developed in parallel but based on information obtained from the hydrological network only (typical for poor data environment). Note that the two convergence length parameters of this simplified model are usually extracted from topography data including cross-sectional area and width along the estuary. Furthermore, freshwater discharge data are needed but these are gauged further upstream outside of the tidal region and unable to reflect the individual flows entering the multi-channel estuary. In order to tackle the poor data environment limitations, a new approach was needed to calibrate the two estuary geometry parameters of the parsimonious salt intrusion model. Compared to

Effects of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida

USGS Publications Warehouse

Langevin, Christian D.; Zygnerski, Michael

2013-01-01

A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise.

Effect of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida.

PubMed

Langevin, Christian D; Zygnerski, Michael

2013-01-01

A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Magnetic fabric in granitoid plutons emplaced during Variscan orogeny and timing of their intrusions: Eastern Variscan front

NASA Astrophysics Data System (ADS)

Hrouda, F.; Schulmann, K.; Chlupacova, M.; Aichler, J.; Mixa, P.; Pecina, V.; Zacek, V.; Kroener, A.

2003-04-01

The eastern Variscan front at the Czech and Polish border is characterised by oblique underthrusting of Neo-Proterozoic continental margin below thickened crustal root. The underthrust plate is subsequently imbricated and forms obliquely convergent crustal wedge which was further thrust over the foreland. Several granitic plutons of arc geochemical affinity are intruded during different stages of crustal thickening and exhumation. Analysis of anisotropy of magnetic susceptibility was carried out to study the relationships between host rock deformation and magma emplacement fabrics in different crustal levels and geographical positions with respect to crustal wedge and westerly orogenic root. Deep seated granodiorite sheets (Javornik intrusion 348 Ma, and Stare Mesto sill 340 Ma) are emplaced in the deepest and more internal high grade parts of the orogen along the margin of thickened crustal root. They show AMS fabrics entirely concordant with surrounding high grade gneisses and were emplaced during contractional (transpressive) regime.The Sumperk granodiorite is a more shallow intrusion emplaced in the central part of the crustal wedge. This sheet-like intrusion shows its AMS fabrics conformable to transpressional fabrics of surrounding mylonitised barovian schists and gneisses. The Zulova Pluton 330 Ma, representing the shallowest intrusion, intrudes the most external part of the crustal wedge. It shows the magnetic fabrics virtually perpendicular to compressional structures in the neighbouring areas. In addition, these fabrics are clearly concordant with large-scale detachment zone along which the Devonian meta-sedimentary cover slided to the west. The AMS fabrics of granitoids thus testify the progressive oblique convergence prograding to the east followed by collapse of external part of orogenic wedge. The AMS fabric data allow us to evaluate the mechanical role of arc magmas syntectonically emplaced during oblique convergence and finally during normal

Investigation of turbulent wedges generated by different single surface roughness elements

NASA Astrophysics Data System (ADS)

Traphan, Dominik; Meinlschmidt, Peter; Lutz, Otto; Peinke, Joachim; Gülker, Gerd

2013-11-01

It is known that small faults on rotor blades of wind turbines can cause significant power loss. In order to better understand the governing physical effects, in this experimental study, the formation of a turbulent wedge over a flat plate induced by single surface roughness elements is under investigation. The experiments are performed at different ambient pressure gradients, thus allowing conclusions about the formation of a turbulent wedge over an airfoil. With respect to typical initial faults on operating airfoils, the roughness elements are modified in both size and shape (raised or recessed). None intrusive experimental methods, such as stereoscopic PIV and LDA, enable investigations based on temporally and spatially highly resolved velocity measurements. In this way, a spectral analysis of the turbulent boundary layer is performed and differences in coherent structures within the wedge are identified. These findings are correlated with global measurements of the wedge carried out by infrared thermography. This correlation aims to enable distinguishing the cause and main properties of a turbulent wedge by the easy applicable method of infrared thermography, which is of practical relevance in the field of condition monitoring of wind turbines.

Important observations and parameters for a salt water intrusion model

USGS Publications Warehouse

Shoemaker, W.B.

2004-01-01

Sensitivity analysis with a density-dependent ground water flow simulator can provide insight and understanding of salt water intrusion calibration problems far beyond what is possible through intuitive analysis alone. Five simple experimental simulations presented here demonstrate this point. Results show that dispersivity is a very important parameter for reproducing a steady-state distribution of hydraulic head, salinity, and flow in the transition zone between fresh water and salt water in a coastal aquifer system. When estimating dispersivity, the following conclusions can be drawn about the data types and locations considered. (1) The "toe" of the transition zone is the most effective location for hydraulic head and salinity observations. (2) Areas near the coastline where submarine ground water discharge occurs are the most effective locations for flow observations. (3) Salinity observations are more effective than hydraulic head observations. (4) The importance of flow observations aligned perpendicular to the shoreline varies dramatically depending on distance seaward from the shoreline. Extreme parameter correlation can prohibit unique estimation of permeability parameters such as hydraulic conductivity and flow parameters such as recharge in a density-dependent ground water flow model when using hydraulic head and salinity observations. Adding flow observations perpendicular to the shoreline in areas where ground water is exchanged with the ocean body can reduce the correlation, potentially resulting in unique estimates of these parameter values. Results are expected to be directly applicable to many complex situations, and have implications for model development whether or not formal optimization methods are used in model calibration.

Important observations and parameters for a salt water intrusion model.

PubMed

Shoemaker, W Barclay

2004-01-01

Sensitivity analysis with a density-dependent ground water flow simulator can provide insight and understanding of salt water intrusion calibration problems far beyond what is possible through intuitive analysis alone. Five simple experimental simulations presented here demonstrate this point. Results show that dispersivity is a very important parameter for reproducing a steady-state distribution of hydraulic head, salinity, and flow in the transition zone between fresh water and salt water in a coastal aquifer system. When estimating dispersivity, the following conclusions can be drawn about the data types and locations considered. (1) The "toe" of the transition zone is the most effective location for hydraulic head and salinity observations. (2) Areas near the coastline where submarine ground water discharge occurs are the most effective locations for flow observations. (3) Salinity observations are more effective than hydraulic head observations. (4) The importance of flow observations aligned perpendicular to the shoreline varies dramatically depending on distance seaward from the shoreline. Extreme parameter correlation can prohibit unique estimation of permeability parameters such as hydraulic conductivity and flow parameters such as recharge in a density-dependent ground water flow model when using hydraulic head and salinity observations. Adding flow observations perpendicular to the shoreline in areas where ground water is exchanged with the ocean body can reduce the correlation, potentially resulting in unique estimates of these parameter values. Results are expected to be directly applicable to many complex situations, and have implications for model development whether or not formal optimization methods are used in model calibration.

Hysteretic behavior in seawater intrusion in response to discontinuous drought periods

NASA Astrophysics Data System (ADS)

Salandin, P.; Darvini, G.

2017-12-01

The seawater intrusion (SWI) represents a relevant problem for communities living in many coastal regions and in small islands, where the amount of fresh water available for human consumption or irrigation purposes depends on the equilibrium between the natural groundwater recharge from precipitations and the surrounding sea. This issue is exacerbated by climate changes, and, as a consequence, the reduction of natural groundwater recharge and the decrease the seaward flows of fresh water rather than sea level rise, as recently demonstrated by Ketabchi et al. (2016), leads to magnify the seawater intrusion into coastal aquifers. The temporal fluctuation of the fresh water table level are a natural consequence of the interaction of the aquifer with a water body or due to the seasonal replenishment of the water table. The severe and prolonged drought phenomena as that observed in last years in some areas of the Mediterranean, as over the central western Mediterranean basin, Italy and Spain, where a decreasing trend in total precipitation was detected (Alpert et al., 2002) in addition to the rise in temperature, enlarges the variation of the freshwater flux and can magnify the progression of the saline wedge. In the present study we demonstrate that the presence of varying boundary constraints or forcing factors may lead to hysteretic behavior in saltwater intrusion, showing dependence of the saline wedge on historic conditions. Therefore, the dynamic behavior of SWI may depend on both the present and past forcing conditions. To this aim different transient simulations supported by evidences deduced from a physical model are carried out to assess the presence of the hysteretic effects in the SWI phenomenon and to evaluate its influence in the management of the coastal aquifers for both the rational exploitation and the corrected management of water resources. About 70% of the world's population dwells in coastal zones. Therefore the optimal exploitation of fresh

Coastal aquifer groundwater dynamics and salt intrusion: Monitoring system of river Neretva delta

NASA Astrophysics Data System (ADS)

Srzić, Veljko; Vranješ, Mijo; Deković, Jure; Romić, Davor; Zovko, Monika; Milin, Marin

2017-04-01

River Neretva delta is located in southern part of Croatia and creates a complex surface- groundwater system influenced by tidal forces characteristic for Adriatic Sea and river Neretva whose discharge varies from 70 - 2700 m3/s over the year. From agricultural point of view, area is used widely for fruit production which implies existence and functionality of complex drainage system consisted of a net of lateral channels and pumping station plants with the capacity of app. 25 m3/s. Area of interest covers app 3500 ha and is bounded by river Neretva from North and Adriatic sea from West. Southern and eastern boundaries are dominantly karstic hills. Lover aquifer is confined with app depth of 65 m, made of fine gravel. Aquitard is a 15 m height layer of clay. Upper aquifer in unconfined with depth of app 10-20 m. Inside the area of interest there are 8 wells installed (each aquifer 4) measuring piezometric head on hourly/daily temporal scale. Sea level measurements are also made capturing for long term tidal oscillations. Discharge measurements are made few km downstream from hydropower plant Mostar (Bosnia and Herzegovina), while three meteorological stations for rainfall measurements are located at the area boundaries. Salt water concentration, pH and resistivity values have been measured locally, app 6 times per year for last 10 years. Results imply confined aquifer is dominantly influenced by the sea level while tidal effects are noticed 9 km upstream the river Neretva with delay of 9-12 minutes compared to sea level. Salt water cline inside the river is related to tidal effects and river discharge, with potential presence at distances of more than 15 km upstream from the sea. Salt water intrusion dominantly occurs through confined aquifer while vertical transport of salt is supposed to be enhanced by the effects of drainage system.

Economic impacts of urban flooding in South Florida: Potential consequences of managing groundwater to prevent salt water intrusion.

PubMed

Czajkowski, Jeffrey; Engel, Vic; Martinez, Chris; Mirchi, Ali; Watkins, David; Sukop, Michael C; Hughes, Joseph D

2018-04-15

High-value urban zones in coastal South Florida are considered particularly vulnerable to salt water intrusion into the groundwater-based, public water supplies caused by sea level rise (SLR) in combination with the low topography, existing high water table, and permeable karst substrate. Managers in the region closely regulate water depths in the extensive South Florida canal network to control closely coupled groundwater levels and thereby reduce the risk of saltwater intrusion into the karst aquifer. Potential SLR adaptation strategies developed by local managers suggest canal and groundwater levels may have to be increased over time to prevent the increased salt water intrusion risk to groundwater resources. However, higher canal and groundwater levels cause the loss of unsaturated zone storage and lead to an increased risk of inland flooding when the recharge from rainfall exceeds the capacity of the unsaturated zone to absorb it and the water table reaches the surface. Consequently, higher canal and groundwater levels are also associated with increased risk of economic losses, especially during the annual wet seasons. To help water managers and urban planners in this region better understand this trade-off, this study models the relationships between flood insurance claims and groundwater levels in Miami-Dade County. Via regression analyses, we relate the incurred number of monthly flood claims in 16 Miami-Dade County watersheds to monthly groundwater levels over the period from 1996 to 2010. We utilize these estimated statistical relationships to further illustrate various monthly flood loss scenarios that could plausibly result, thereby providing an economic quantification of a "too much water" trade-off. Importantly, this understanding is the first of its kind in South Florida and is exceedingly useful for regional-scale hydro-economic optimization models analyzing trade-offs associated with high water levels. Copyright © 2017 Elsevier B.V. All rights

Enrichment of fluoride in groundwater under the impact of saline water intrusion at the salt lake area of Yuncheng basin, northern China

NASA Astrophysics Data System (ADS)

Gao, Xubo; Wang, Yanxin; Li, Yilian; Guo, Qinghai

2007-12-01

Long-term intake of high-fluoride groundwater causes endemic fluorosis. This study, for the first time, discovered that the salt lake water intrusion into neighboring shallow aquifers might result in elevation of fluoride content of the groundwater. Two cross-sections along the groundwater flow paths were selected to study the geochemical processes controlling fluoride concentration in Yuncheng basin, northern China. There are two major reasons for the observed elevation of fluoride content: one is the direct contribution of the saline water; the other is the undersaturation of the groundwater with respect to fluorite due to salt water intrusion, which appears to be more important reason. The processes of the fluorine activity reduction and the change of Na/Ca ratio in groundwater induced by the intrusion of saline water favor further dissolution of fluorine-bearing mineral, and it was modeled using PHREEQC. With the increase in Na concentration (by adding NaCl or Na2SO4 as Na source, calcium content kept invariable), the increase of NaF concentration was rapid at first and then became slower; and the concentrations of HF, HF{2/-}, CaF+, and MgF+ were continuously decreasing. The geochemical conditions in the study area are advantageous to the complexation of F- with Na+ and the decline of saturation index of CaF2, regardless of the water type (Cl-Na or SO4-Na type water).

The Río de la Plata estuary response to wind variability in synoptic time scale: Salinity fields and salt wedge structure

NASA Astrophysics Data System (ADS)

Meccia, V. L.; Simionato, C. G.; Guerrero, R. A.

2009-04-01

The Río de la Plata estuary is located in the eastern coast of southern South America, approximately at 35° S. It has a northwest to southeast oriented funnel shape approximately 300 km long that narrows from 220 km at its mouth to 40 km at its upper end. With a mean discharge of 25,000 m3 s-1 and a drainage area of 3.5 × 106 km2 it ranks fourth and fifth worldwide in freshwater discharge and drainage area, respectively. The interaction between estuarine and shelf waters originates an intense and active salinity front which plays an important role in the flow dynamics and the distribution of properties on the shelf. As a result of the constant displacement of the surface front and the steadiness of the bottom front whose location is controlled by the bathymetry, a time-variable salt wedge structure is observed in the estuary during most of the year. In this work, Estuary, Coastal and Ocean Model (ECOM) was applied to study the processes associated to the salinity fields and the salt wedge structure in the Río de la Plata estuary. It was found that salinity fields in the Río de la Plata rapidly respond -order of 3 days- to wind variability. Therefore, the traditional conceptual scheme that considers seasonal variability as the main feature of the salinity field in this estuary does not longer hold and conditions classically though as characteristic of ‘winter' or ‘summer' can take place during any season with high variability. The estuary response to wind variability can be explained in terms of four characteristic patterns associated to winds that blow with dominant components perpendicular and parallel to the estuary axis. Northeasterly winds produce a southwestward retraction of the surface salinity front. The results are consistent with upwelling motion along the Uruguayan coast under this wind direction. Southwesterly winds produce a northward displacement of the surface salinity front towards the Uruguayan coast and, according to our simulations, a

Ultrasonic fluid densitometer having liquid/wedge and gas/wedge interfaces

DOEpatents

Greenwood, Margaret S.

2000-01-01

The present invention is an ultrasonic liquid densitometer that uses a material wedge having two sections, one with a liquid/wedge interface and another with a gas/wedge interface. It is preferred that the wedge have an acoustic impedance that is near the acoustic impedance of the liquid, specifically less than a factor of 11 greater than the acoustic impedance of the liquid. Ultrasonic signals are internally reflected within the material wedge. Density of a liquid is determined by immersing the wedge into the liquid and measuring reflections of ultrasound at the liquid/wedge interface and at the gas/wedge interface.

Geoelectrical and hydrochemical study for the assessment of seawater intrusion evolution in coastal aquifers of Oualidia, Morocco

NASA Astrophysics Data System (ADS)

Fadili, Ahmed; Najib, Saliha; Mehdi, Khalid; Riss, Joëlle; Malaurent, Philippe; Makan, Abdelhadi

2017-11-01

This study aims to assess the evolution of seawater intrusion between 1992 and 2011 periods in the coastal aquifers of Oualidia. To achieve this objective, the combination of geoelectrical and hydrochemical methods was adopted. Apparent resistivity maps, using 74 Vertical Electrical Sounding (VES) performed on 1992, allowed to distinguish two different zones. The conductive one, with apparent resistivity ranging between 4 and 86 Ω·m, is limited to 1 km with respect to the ocean. Meanwhile, the resistant one is much farther from the coastline. Besides, results of Electrical Resistivity Tomography (ERT) profiles performed during 2011 are in good agreement with those obtained by apparent resistivity maps. The ERT profiles show a conductive level characterized by low resistivity below 30 Ω·m assigned to seawater intrusion effect. Moreover, hydrochemical analysis, performed on 19 wells during three different periods, on June, December 2010 and May 2011, indicates that the most affected part with marine waters was at that time localized in the first kilometer from the ocean, with high amounts of Na+ and Cl- ions. Beyond this fringe, mineralization becomes very weak. Overall, the comparison of old VES with recent ERT coupled with hydrochemical results suggest no important evolution of the salt wedge since 1992.

Radial wedge flange clamp

DOEpatents

Smith, Karl H.

2002-01-01

A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

Organic pollution and salt intrusion in Cai Nuoc District, Ca Mau Province, Vietnam.

PubMed

Tho, Nguyen; Vromant, Nico; Hung, Nguyen Thanh; Hens, Luc

2006-07-01

In Ca Mau, Vietnam, farmers converted from rice to shrimp farming, while ignoring the degradation of the aquatic environment. We assessed the seasonal variations in organic pollution of the surface water and salt intrusion in one district and assessed the difference in chemical characteristics of the surface water of shrimp ponds and canals. Several variables reflecting salinity and organic pollution were measured in the wet and dry season. The results show that in the dry season salinity increased to 37.36-42.73 g l(-1) and COD and suspended solids increased to a maximum of 268.7 mg l(-1) and 1312.0 mg l(-1), respectively. In the wet season salinity values of 8.16 to 10.60 g l(-1) were recorded, indicating that salinity could no longer be washed out completely in this season. It is concluded that salinity and suspended solids in the aquatic environment in the Cai Nuoc district are increased by shrimp monoculture, whereas organic pollution is contributed by human population pressure.

Hydrogeology and extent of saltwater intrusion on Manhasset Neck, Nassau County, New York

USGS Publications Warehouse

Stumm, Frederick; Lange, Andrew D.; Candela, J.L.

2002-01-01

-supply wells screened in the Magothy and upper glacial aquifers contained volatile organic compounds in concentrations above the New York State Department of Health Drinking Water maximum contaminant levels, as did water from one public- supply well screened in the Lloyd aquifer and from two observation wells screened in the upper glacial aquifer.Five distinct areas of saltwater intrusion have been delineated in Manhasset Neck; three extend into the Lloyd and North Shore aquifers, and two extend into the upper glacial and Magothy aquifers. Borehole-geophysical-logging data indicate that several of these saltwater wedges range from a few feet to more than 125 feet in thickness and have sharp freshwater-saltwater interfaces, and that chloride concentrations within these wedges in 1997 ranged from 102 to 9,750 milligrams per liter. Several public-supply wells have either been shut down or are currently being affected by these saltwater wedges. Data show active saltwater intrusion in at least two of the wedges.

Diving wedges

NASA Astrophysics Data System (ADS)

Vincent, Lionel; Kanso, Eva

2017-11-01

Diving induces large pressures during water entry, accompanied by the creation of cavity behind the diver and water splash ejected from the free water surface. To minimize impact forces, divers streamline their shape at impact. Here, we investigate the impact forces and splash evolution of diving wedges as a function of the wedge opening angle. A gradual transition from impactful to smooth entry is observed as the wedge angle decreases. After submersion, diving wedges experience significantly smaller drag forces (two-fold smaller) than immersed wedges. We characterize the shapes of the cavity and splash created by the wedge and find that they are independent of the entry velocity at short times, but that the splash exhibits distinct variations in shape at later times. Combining experimental approach and a discrete fluid particle model, we show that the splash shape is governed by a destabilizing Venturi-suction force due to air rushing between the splash and the water surface and a stabilizing force due to surface tension. These findings may have implications in a wide range of water entry problems, with applications in engineering and bio-related problems, including naval engineering, disease spreading and platform diving. This work was funded by the National Science Foundation.

Air pollutant intrusion into the Wieliczka Salt Mine

USGS Publications Warehouse

Salmon, L.G.; Cass, G.R.; Kozlowski, R.; Hejda, A.; Spiker, E. C.; Bates, A.L.

1996-01-01

The Wieliczka Salt Mine World Cultural Heritage Site contains many rock salt sculptures that are threatened by water vapor condensation from the mine ventilation air. Gaseous and particulate air pollutant concentrations have been measured both outdoors and within the Wieliczka Salt Mine, along with pollutant deposition fluxes to surfaces within the mine. One purpose of these measurements was to determine whether or not low deliquescence point ionic materials (e.g., NH4NO3) are accumulating on surfaces to an extent that would exacerbate the water vapor condensation problems in the mine. It was found that pollutant gases including SO2 and HNO3 present in outdoor air are removed rapidly and almost completely from the air within the mine by deposition to surfaces. Sulfur isotope analyses confirm the accumulation of air pollutant-derived sulfur in liquid dripping from surfaces within the mine. Particle deposition onto interior surfaces in the mine is apparent, with resulting soiling of some of those sculptures that have been carved from translucent rock salt. Water accumulation by salt sculpture surfaces was studied both experimentally and by approximate thermodynamic calculations. Both approaches suggest that the pollutant deposits on the sculpture surfaces lower the relative humidity (RH) at which a substantial amount of liquid water will accumulate by 1% to several percent. The extraordinarily low SO2 concentrations within the mine may explain the apparent success of a respiratory sanatorium located deep within the mine.

A new physical barrier system for seawater intrusion control

NASA Astrophysics Data System (ADS)

Abdoulhalik, Antoifi; Ahmed, Ashraf; Hamill, G. A.

2017-06-01

The construction of subsurface physical barriers is one of various methods used to control seawater intrusion (SWI) in coastal aquifers. This study proposes the mixed physical barrier (MPB) as a new barrier system for seawater intrusion control, which combines an impermeable cutoff wall and a semi-permeable subsurface dam. The effect of the traditionally-used physical barriers on transient saltwater wedge dynamics was first explored for various hydraulic gradients, and the workability of the MPB was thereafter thoroughly analysed. A newly developed automated image analysis based on light-concentration conversion was used in the experiments, which were completed in a porous media tank. The numerical code SEAWAT was used to assess the consistency of the experimental data and examine the sensitivity of the performance of the barriers to various key parameters. The results show that the MPB induced a visible lifting of the dense saline flux upward towards the outlet by the light freshwater. This saltwater lifting mechanism, observed for the first time, induced significant reduction to the saline water intrusion length. The use of the MPB yielded up to 62% and 42% more reduction of the saltwater intrusion length than the semi-permeable dam and the cutoff wall, respectively. The performance achieved by the MPB with a wall depth of 40% of the aquifer thickness was greater than that of a single cutoff wall with a penetration depth of 90% of the aquifer thickness (about 13% extra reduction). This means that the MPB could produce better seawater intrusion reduction than the traditionally used barriers at even lower cost.

On the Salt Water Intrusion into the Durusu Lake, Istanbul: A Joint Central Loop TEM And Multi-Electrode ERT Field Survey

NASA Astrophysics Data System (ADS)

Ardali, Ayça Sultan; Tezkan, Bülent; Gürer, Aysan

2018-02-01

Durusu Lake is the biggest and most important freshwater source supplying drinking water to the European side of Istanbul. In this study, electrical resistivity tomography (ERT) and transient electromagnetic (TEM) measurements were applied to detect a possible salt water intrusion into the lake and to delineate the subsurface structure in the north of Durusu Lake. The ERT and TEM measurements were carried out along six parallel profiles extending from the sea coast to the lake shore on the dune barrier. TEM data were interpreted using different 1-D inversion methods such as Occam, Marquardt, and laterally constrained inversion (LCI). ERT data were interpreted using 2-D inversion techniques. The inversion results of ERT and TEM data were shown as resistivity depth sections including topography. The sand layer spreading over the basin has a resistivity of 150-400 Ωm with a thickness of 5-10 m. The sandy layer with clay, silt, and gravel has a resistivity of 15-100 Ωm and a thickness of 10-40 m followed by a clay layer of a resistivity below 10 Ωm. When the inversion of these data is interpreted along with the hydrogeology of the area, it is concluded that the salt water intrusion along the dune barrier is not common and occurs at a particular area where the distance between lake and sea is very close. Using information from boreholes around the lake, it was verified that the common conductive region at depths of 30 m or more consists of clay layers and clay lenses.

Double salt décollements: Effect of pinch-out overlapping in experimental thrust wedges

NASA Astrophysics Data System (ADS)

Santolaria, P.; Vendeville, B.; Graveleau, F.; Casas, A.; Soto, R.

2013-12-01

The presence of one or more evaporitic horizons acting as detachment levels in fold-and-thrust belts is common. Numerous works have dealt with the analysis of the role played by basal detachments on the deformation style of fold-and-thrust belts, but less attention has been paid to the interaction between two décollements and strain transfer between them. In this study, 10 sand-silicone analogue experiments with two detachment levels and different stratigraphic pinch-out configurations were carried out: the basal décollement was located hinterlandwards, and the upper one was located forelandwards, with or without geographic underlap or overlap. These geometrical arrangements simulate evaporites deposited in foreland basins progressively involved in shortening. To analyze their influence on the geometry and kinematics of thrust wedges, we tested successively the following parameters: i) the amount of vertical overlapping between the two décollement pinch-outs, ii) the total amount of shortening, and iii) the geometry of the intermediate décollement (pinch-out line parallel or oblique with respect to the pinch-out line of the basal décollement). All experiments were quantitatively monitored by carrying DEM (Digital Elevation Models) and PIV (Particle Image Velocimetry) measurements. All models had a similar style: (i) an inner domain, characterized by a thicker sand cover, with three forward verging thrusts rooted in the basal décollement, (ii) an outer domain with thinner sand cover, whose deformation pattern was characterized by 2 to 6 structures detaching on the upper décollement and (iii) a 'step zone' located between the inner and outer domains having varying geometry and kinematics. In longer-lived models, structures were reworked and salt migration deformed the early emplaced folds and thrusts. Our experimental results point out that the amount of vertical overlapping between the two décollement pinch outs is a first order parameter that conditions not

Salt intrusion in tidal wetlands: European willow species tolerate oligohaline conditions

NASA Astrophysics Data System (ADS)

Markus-Michalczyk, Heike; Hanelt, Dieter; Ludewig, Kristin; Müller, David; Schröter, Brigitte; Jensen, Kai

2014-01-01

Tidal wetlands experience salt intrusion due to the effects of climate change. This study clarifies that the European flood plain willows species Salix alba and Salix viminalis tolerate oligohaline conditions. Salix alba L. and Salix viminalis L. are distributed on flood plains up to transitional waters of the oligohaline to the mesohaline estuarine stretch in temperate climates. They experience spatial and temporal variations in flooding and salinity. In the past, willows dominated the vegetation above the mean high water line, attenuated waves and contributed to sedimentation. In recent centuries, human utilization reduced willow stands. Today, the Elbe estuary - a model system for an estuary in temperate zones - exhibits increasing flooding and salinity due to man-induced effects and climatic changes. Willows were described as having no salinity tolerance. In contrast, our soil water salinity measurements at willows in tidal wetlands prove that mature Salix individuals tolerate oligohaline conditions. To assess immature plant salinity tolerance, we conducted a hydroponic greenhouse experiment. Vegetative propagules originating from a freshwater and an oligohaline site were treated in four salinities. Related to growth rates and biomass production, we found interspecific similarities and a salinity tolerance up to salinity 2. Vitality and chlorophyll fluorescence indicated an acclimation of Salix viminalis to oligohaline conditions. We conclude, that the survival of S. alba and S. viminalis and the restoration of willow stands in estuarine flood plains - with regard to wave attenuation and sedimentation - might be possible, despite increasing salinity in times of climate change.

Characterization and calibration of seawater intrusion models using electrical resistivity tomography (Invited)

NASA Astrophysics Data System (ADS)

Nguyen, F. H.; Kemna, A.; Antonsson, A.; Engesgaard, P. K.; Beaujean, J.

2009-12-01

The urban development of coastal regions create seawater intrusion (SWI) problems which threatens groundwater quality and coastal ecosystems. To study SWI, one needs both robust measuring technologies, and reliable predictions. A key aspect in the calibration of SWI models involves reproducing measured groundwater chloride concentrations. Drilling such multi-screen wells to obtain a whole concentration profile is a risky task if reliable information about the position of the salt wedge is not available. Electrical resistivity tomography (ERT) is increasingly being used to characterize seawater intrusion and constrain corresponding models, given its high sensitivity to ion concentration in groundwater and its relatively high spatial resolution. We have investigated the potential of ERT using field data from a site in Almeria, SE Spain and synthetic data. Simulations have been run for several scenarios, with a simple hydrogeological model reflecting the local site conditions. The simulations showed that only the lower salt concentrations of the seawater-freshwater transition zone could be recovered, due to the loss of resolution with depth. We quantified this capability in terms of image appraisal indicators (cumulative sensitivity) associated with the measurement setup and showed that the mismatch between the targeted and imaged parameter values occurs from a certain threshold. Similarly, heterogeneity may only be determined accurately if located in an adequately sensitive area. Inversion of the synthetic data was performed by coupling an inversion code (PEST) with a finite-difference density-dependent flow and transport modeling code (HTS). The numerical results demonstrate the capacity of sensitivity-filtered ERT images to constrain transverse hydraulic dispersivity and longitudinal hydraulic conductivity of homogeneous seawater intrusion models. At the field site, we identified SWI at the scale of a few kilometers down to a hundred meters. Borehole logs show a

Marshes on the Move: Testing effects of seawater intrusion on ...

EPA Pesticide Factsheets

The Northeastern United States is a hotspot for sea level rise (SLR), subjecting coastal salt marshes to erosive loss, shifts in vegetation communities, and altered biogeochemistry due to seawater intrusion. Salt marsh plant community zonation is driven by tradeoffs in stress tolerance and interspecific interactions. As seawater inundates progressively higher marsh elevations, shifts in marsh vegetation communities landward may herald salt marsh “migration”, which could allow continuity of marsh function and ecosystem service provision. To elucidate possible effects of seawater intrusion on marsh-upland edge plant communities, a space-for-time approach was replicated at two Rhode Island salt marshes. At each site, peat blocks (0.5 m x 0.5 m x 0.5 m, n=6) with intact upland-marsh edge vegetation were transplanted downslope into the regularly-inundated mid-marsh. Procedural controls (n=3) were established at each elevation by removing and replacing peat blocks, and natural controls (n=3) consisted of undisturbed plots. During peak productivity, each plot was assessed for species composition, percent cover and average height. Results demonstrate stunting of marsh-upland edge vegetation in response to increased inundation, and the beginnings of colonization of the transplanted plots by salt marsh species. The extent of colonization differed between the two sites, suggesting that site-specific factors govern vegetation responses to increased inundation.

Quasi-horizontal circulation cells in 3D seawater intrusion

USGS Publications Warehouse

Abarca, E.; Carrera, J.; Sanchez-Vila, X.; Voss, C.I.

2007-01-01

The seawater intrusion process is characterized by the difference in freshwater and seawater density that causes freshwater to float on seawater. Many confined aquifers have a large horizontal extension with respect to thickness. In these cases, while buoyancy acts in the vertical direction, flow is confined between the upper and bottom boundaries and the effect of gravity is controlled by variations of aquifer elevation. Therefore, the effective gravity is controlled by the slope and the shape of the aquifer boundaries. Variability in the topography of the aquifer boundaries is one case where 3D analysis is necessary. In this work, density-dependent flow processes caused by 3D aquifer geometry are studied numerically and specifically, considering a lateral slope of the aquifer boundaries. Sub-horizontal circulation cells are formed in the saltwater entering the aquifer. The penetration of the saltwater can be quantified by a dimensionless buoyancy number that measures the lateral slope of the aquifer relative to freshwater flux. The penetration of the seawater intrusion wedge is controlled more by this slope than by the aquifer thickness and dispersivity. Thus, the slope must be taken into account in order to accurately evaluate seawater intrusion. ?? 2007 Elsevier B.V. All rights reserved.

Modeling coliform-bacteria concentrations and pH in the salt-wedge reach of the Duwamish River Estuary, King County, Washington

USGS Publications Warehouse

Haushild, W.L.; Prych, Edmund A.

1976-01-01

Total- and fecal-coliform bacteria, plus pH, alkalinity, and dissolved inorganic carbon are water-quality parameters that have been added to an existing numerical model of water quality in the salt-wedge reach of the Duwamish River estuary in Washington. The coliform bacteria are modeled using a first-order decay (death) rate, which is a function of the local salinity, temperature, and daily solar radiation. The pH is computed by solving a set of chemical-equilibrium equations for carbonate-bicarbonate buffered aqueous solutions. Concentrations of total- and fecal-coliform bacteria computed by the model for the Duwamish River estuary during June-September 1971 generally agreed with observed concentrations within about 40 and 60 percent, respectively. The computed pH generally agreed with observed pH within about a 0.2 pH unit; however, for one 3-week period the computed pH was about a 0.4 unit lower than the observed pH. (Woodard-USGS)

The Cosmonaut Sea Wedge

USGS Publications Warehouse

Solli, K.; Kuvaas, B.; Kristoffersen, Y.; Leitchenkov, G.; Guseva, J.; Gandyukhin, V.

2007-01-01

A set of multi-channel seismic profiles (~15000 km) acquired by Russia, Norway and Australia has been used to investigate the depositional evolution of the Cosmonaut Sea margin of East Antarctica. We recognize a regional sediment wedge below the upper part of the continental rise. The wedge, herein termed the Cosmonaut Sea Wedge, is positioned stratigraphically underneath the inferred glaciomarine section and extends for at least 1200 km along the continental margin and from 80 to about 250 km seaward or to the north. Lateral variations in the growth pattern of the wedge indicate several overlapping depocentres, which at their distal northern end are flanked by elongated mounded drifts and contourite sheets. The internal stratification of the mounded drift deposits suggests that westward flowing bottom currents reworked the marginal deposits. The action of these currents together with sea-level changes is considered to have controlled the growth of the wedge. We interpret the Cosmonaut Sea Wedge as a composite feature comprising several bottom current reworked fan systems.

Dosimetric Characteristics of Wedged Fields

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

Sidhu, N.P.S.; Breitman, Karen

2015-01-15

The beam characteristics of the wedged fields in the nonwedged planes (planes normal to the wedged planes) were studied for 6 MV and 15 MV x-ray beams. A method was proposed for determining the maximum field length of a wedged field that can be used in the nonwedged plane without introducing undesirable alterations in the dose distributions of these fields. The method requires very few measurements. The relative wedge factors of 6 MV and 15 MV X-rays were determined for wedge filters of nominal wedge angles of 15°, 30°, 45°, and 60° as a function of depth and field size.more » For a 6 MV beam the relative wedge factors determined for a field size of 10 × 10 cm{sup 2} for 30°, 45°, and 60° wedge filters can be used for various field sizes ranging from 4 cm{sup 2} to 20 cm{sup 2} (except for the 60° wedge for which the maximum field size that can be used is 15 × 20 cm{sup 2}) without introducing errors in the dosimetric calculations of more than 0.5% for depths up to 20 cm and 1% for depths up to 30 cm. For the 15° wedge filter the relative wedge factor for a field size of 10 × 10 cm{sup 2} can be used over the same range of field sizes by introducing slightly higher error, 0.5% for depths up to 10 cm and 1% for depths up to 30 cm. For a 15 MV beam the maximum magnitude of the relative wedge factors for 45° and 60° lead wedges is of the order of 1%, and it is not important clinically to apply a correction of that magnitude. For a 15 MV beam the relative wedge factors determined for a field size of 6 × 6 cm{sup 2} for the 15° and 30° steel wedges can be used over a range of field sizes from 4 cm{sup 2} to 20 cm{sup 2} without causing dosimetric errors greater than 0.5% for depths up to 10 cm.« less

Interfacial Granular Intrusions

NASA Astrophysics Data System (ADS)

Linden, Paul; Zheng, Zhong; Huppert, Herbert; Vriend, Nathalie; Neufeld, Jerome

2017-11-01

We study experimentally the intrusion of light granular material into an inviscid fluid of greater density. Despite a rich set of related geophysical and environmental phenomena, such as the spreading of calved ice and volcanic ash and debris flows, there are few previous studies on this topic. We conduct a series of lock-release experiments of light spherical beads into a rectangular tank initially filled with either fresh water or salt water, and record the time evolution of the interface shape and the front location of the current of beads. In particular, we find that the front location obeys a power-law behaviour during an intermediate time period following the release of the lock before the nose of beads reaches a maximum runout distance within a finite time. We investigate the dependence of the scaling exponent and runout distance on the total amount of beads, the initial lock length, and the properties of the liquid that fills the tank in the experiments. Appropriate scaling arguments are provided to collapse the raw experimental data into universal curves, which can be used to describe the front dynamics of light granular intrusions with different size and buoyancy effects and initial aspect ratios.

Interactive Modelling of Salinity Intrusion in the Rhine-Meuse Delta

NASA Astrophysics Data System (ADS)

Baart, F.; Kranenburg, W.; Luijendijk, A.

2015-12-01

In many delta's of the world salinity intrusion imposes limits to fresh water availability. With increasing population and industry, the need for fresh water increases. But also salinity intrusion is expected to increase due to changes in river discharge, sea level and storm characteristics. In the Rhine-Meuse delta salt intrusion is impacted by human activities as well, like deepening of waterways and opening of delta-branches closed earlier. All these developments call for increasing the understanding of the system, but also for means for policy makers, coastal planners and engineers to assess effects of changes and to explore and design measures. In our presentation we present the developments in interactive modelling of salinity intrusion in the Rhine-Meuse delta. In traditional process-based numerical modelling, impacts are investigated by researchers and engineers by following the steps of pre-defining scenario's, running the model and post-processing the results. Interactive modelling lets users adjust simulations while running. Users can for instance change river discharges or bed levels, and can add measures like changes to geometry. The model will take the adjustments into account immediately, and will directly compute the effect. In this way, a tool becomes available with which coastal planners, policy makers and engineers together can develop and evaluate ideas and designs by interacting with the numerical model. When developing interactive numerical engines, one of the challenges is to optimize the exchange of variables as e.g. salt concentration. In our case we exchange variables on a 3D grid every time step. For this, the numerical model adheres to the Basic Model Interface (http://csdms.colorado.edu/wiki), which allows external control and the exchange of variables through pointers while the model is running. In our presentation we further explain our method and show examples of interactive design of salinity intrusion measures in the Rhine

Thermally actuated wedge block

DOEpatents

Queen, Jr., Charles C.

1980-01-01

This invention relates to an automatically-operating wedge block for maintaining intimate structural contact over wide temperature ranges, including cryogenic use. The wedging action depends on the relative thermal expansion of two materials having very different coefficients of thermal expansion. The wedge block expands in thickness when cooled to cryogenic temperatures and contracts in thickness when returned to room temperature.

Sojourner APXS & Wedge

NASA Image and Video Library

1997-08-27

This image of the rock "Wedge" was taken from the Sojourner rover's rear color camera on Sol 37. The position of the rover relative to Wedge is seen in MRPS 83349. The segmented rod visible in the middle of the frame is the deployment arm for the Alpha Proton X-Ray Spectrometer (APXS). The APXS, the bright, cylindrical object at the end of the arm, is positioned against Wedge and is designed to measure the rock's chemical composition. This was done successfully on the night of Sol 37. http://photojournal.jpl.nasa.gov/catalog/PIA00906

Monitoring CO2 sequestration into deep saline aquifer and associated salt intrusion using coupled multiphase flow modeling and time-lapse electrical resistivity tomography

NASA Astrophysics Data System (ADS)

Lu, C.; Zhang, C.; Huang, H.; Johnson, T.

2012-12-01

Geological sequestration of carbon dioxide (CO2) into the subsurface has been considered as one solution to reduce greenhouse emission to the atmosphere. Successful sequestration process requires efficient and adequate monitoring of injected fluids as they migrate into the aquifer to evaluate flow path, leakage, and geochemical interactions between CO2 and geologic media. In this synthetic field scale study, we have integrated 3D multiphase flow modeling code PFLOTRAN with 3D time-laps electrical resistivity tomography (ERT) to gain insight into the supercritical (SC) CO2 plumes movement in the deep saline aquifer and associated brine intrusion into shallower fresh water aquifer. A parallel ERT forward and inverse modeling package was introduced, and related algorithms are briefly described. The capabilities and limitations of ERT in monitoring CO2 migration are assessed by comparing the results from PFLOTRAN simulations with the ERT inversion results. In general, our study shows the ERT inversion results compare well with PFLOTRAN with reasonable discrepancies, indicating that the ERT can capture the actual CO2 plume dynamics and brine intrusion. Detailed comparisons on the location, size and volume of CO2 plume show the ERT method underestimated area review and overestimated total plume volume in the predictions of SC CO2 movements. These comparisons also show the ERT method constantly overestimate salt intrusion area and underestimated total solute amount in the predictions of brine filtration. Our study shows that together with other geochemical and geophysical methods, ERT is a potentially useful monitoring tool in detecting the SC CO2 and formation fluid migrations.

Observation of the dispersion of wedge waves propagating along cylinder wedge with different truncations by laser ultrasound technique

NASA Astrophysics Data System (ADS)

Jia, Jing; Zhang, Yu; Han, Qingbang; Jing, Xueping

2017-10-01

The research focuses on study the influence of truncations on the dispersion of wedge waves propagating along cylinder wedge with different truncations by using the laser ultrasound technique. The wedge waveguide models with different truncations were built by using finite element method (FEM). The dispersion curves were obtained by using 2D Fourier transformation method. Multiple mode wedge waves were observed, which was well agreed with the results estimated from Lagasse's empirical formula. We established cylinder wedge with radius of 3mm, 20° and 60°angle, with 0μm, 5μm, 10μm, 20μm, 30μm, 40μm, and 50μm truncations, respectively. It was found that non-ideal wedge tip caused abnormal dispersion of the mode of cylinder wedge, the modes of 20° cylinder wedge presents the characteristics of guide waves which propagating along hollow cylinder as the truncation increasing. Meanwhile, the modes of 60° cylinder wedge with truncations appears the characteristics of guide waves propagating along hollow cylinder, and its mode are observed clearly. The study can be used to evaluate and detect wedge structure.

Evaluating the dose to the contralateral breast when using a dynamic wedge versus a regular wedge.

PubMed

Weides, C D; Mok, E C; Chang, W C; Findley, D O; Shostak, C A

1995-01-01

The incidence of secondary cancers in the contralateral breast after primary breast irradiation is several times higher than the incidence of first time breast cancer. Studies have shown that the scatter radiation to the contralateral breast may play a large part in the induction of secondary breast cancers. Factors that may contribute to the contralateral breast dose may include the use of blocks, the orientation of the field, and wedges. Reports have shown that the use of regular wedges, particularly for the medial tangential field, gives a significantly higher dose to the contralateral breast compared to an open field. This paper compares the peripheral dose outside the field using a regular wedge, a dynamic wedge, and an open field technique. The data collected consisted of measurements taken with patients, solid water and a Rando phantom using a Varian 2300CD linear accelerator. Ion chambers, thermoluminescent dosimeters (TLD), diodes, and films were the primary means for collecting the data. The measurements show that the peripheral dose outside the field using a dynamic wedge is close to that of open fields, and significantly lower than that of regular wedges. This information indicates that when using a medial wedge, a dynamic wedge should be used.

Rethinking wedges

NASA Astrophysics Data System (ADS)

Davis, Steven J.; Cao, Long; Caldeira, Ken; Hoffert, Martin I.

2013-03-01

Abstract Stabilizing CO2 emissions at current levels for fifty years is not consistent with either an atmospheric CO2 concentration below 500 ppm or global temperature increases below 2 °C. Accepting these targets, solving the climate problem requires that emissions peak and decline in the next few decades, and ultimately fall to near zero. Phasing out emissions over 50 years could be achieved by deploying on the order of 19 'wedges', each of which ramps up linearly over a period of 50 years to ultimately avoid 1 GtC y-1 of CO2 emissions. But this level of mitigation will require affordable carbon-free energy systems to be deployed at the scale of tens of terawatts. Any hope for such fundamental and disruptive transformation of the global energy system depends upon coordinated efforts to innovate, plan, and deploy new transportation and energy systems that can provide affordable energy at this scale without emitting CO2 to the atmosphere. 1. Introduction In 2004, Pacala and Socolow published a study in Science arguing that '[h]umanity can solve the carbon and climate problem in the first half of this century simply by scaling up what we already know how to do' [1]. Specifically, they presented 15 options for 'stabilization wedges' that would grow linearly from zero to 1 Gt of carbon emissions avoided per year (GtC y-1 1 Gt = 1012 kg) over 50 years. The solution to the carbon and climate problem, they asserted, was 'to deploy the technologies and/or lifestyle changes necessary to fill all seven wedges of the stabilization triangle'. They claimed this would offset the growth of emissions and put us on a trajectory to stabilize atmospheric CO2 concentration at 500 ppm if emissions decreased sharply in the second half of the 21st century. The wedge concept has proven popular as an analytical tool for considering the potential of different technologies to reduce CO2 emissions. In the years since the paper was published, it has been cited more than 400 times, and

Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary

PubMed Central

Shaha, Dinesh Chandra; Cho, Yang-Ki

2016-01-01

Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE. PMID:27255892

Phase Space Exchange in Thick Wedge Absorbers

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

Neuffer, David

The problem of phase space exchange in wedge absorbers with ionization cooling is discussed. The wedge absorber exchanges transverse and longitudinal phase space by introducing a position-dependent energy loss. In this paper we note that the wedges used with ionization cooling are relatively thick, so that single wedges cause relatively large changes in beam phase space. Calculation methods adapted to such “thick wedge” cases are presented, and beam phase-space transformations through such wedges are discussed.

Inclined indentation of smooth wedge in rock mass

NASA Astrophysics Data System (ADS)

Chanyshev, AI; Podyminogin, GM; Lukyashko, OA

2018-03-01

The article focuses on the inclined rigid wedge indentation into a rigid-plastic half-plane of rocks with the Mohr–Coulomb-Mohr plasticity. The limiting loads on different sides of the wedge are determined versus the internal friction angle, cohesion and wedge angle. It is shown that when the force is applied along the symmetry axis of the wedge, the zone of plasticity is formed only on one wedge side. In order to form the plasticity zone on both sides of the wedge, it is necessary to apply the force asymmetrically relative to the wedge symmetry axis. An engineering solution for the asymmetrical case implementation is suggested.

A simulation/optimization study to assess seawater intrusion management strategies for the Gaza Strip coastal aquifer (Palestine)

NASA Astrophysics Data System (ADS)

Dentoni, Marta; Deidda, Roberto; Paniconi, Claudio; Qahman, Khalid; Lecca, Giuditta

2015-03-01

Seawater intrusion is one of the major threats to freshwater resources in coastal areas, often exacerbated by groundwater overexploitation. Mitigation measures are needed to properly manage aquifers, and to restore groundwater quality. This study integrates three computational tools into a unified framework to investigate seawater intrusion in coastal areas and to assess strategies for managing groundwater resources under natural and human-induced stresses. The three components are a three-dimensional hydrogeological model for density-dependent variably saturated flow and miscible salt transport, an automatic calibration procedure that uses state variable outputs from the model to estimate selected model parameters, and an optimization module that couples a genetic algorithm with the simulation model. The computational system is used to rank alternative strategies for mitigation of seawater intrusion, taking into account conflicting objectives and problem constraints. It is applied to the Gaza Strip (Palestine) coastal aquifer to identify a feasible groundwater management strategy for the period 2011-2020. The optimized solution is able to: (1) keep overall future abstraction from municipal groundwater wells close to the user-defined maximum level, (2) increase the average groundwater heads, and (3) lower both the total mass of salt extracted and the extent of the areas affected by seawater intrusion.

Europa Wedge Region

NASA Technical Reports Server (NTRS)

1998-01-01

This image shows an area of crustal separation on Jupiter's moon, Europa. Lower resolution pictures taken earlier in the tour of NASA's Galileo spacecraft revealed that dark wedge-shaped bands in this region are areas where the icy crust has completely pulled apart. Dark material has filled up from below and filled the void created by this separation.

In the lower left corner of this image, taken by Galileo's onboard camera on December 16, 1997, a portion of one dark wedge area is visible, revealing a linear texture along the trend of the wedge. The lines of the texture change orientation slightly and reflect the fact that we are looking at a bend in the wedge. The older, bright background, visible on the right half of the image, is criss-crossed with ridges. A large, bright ridge runs east-west through the upper part of the image, cutting across both the older background plains and the wedge. This ridge is rough in texture, with numerous small terraces and troughs containing dark material.

North is to the top of the picture and the sun illuminates the surface from the northwest. This image, centered at approximately 16.5 degrees south latitude and 196.5 degrees west longitude, covers an area approximately 10 kilometers square (about 6.5 miles square). The resolution of this image is about 26 meters per picture element. This image was taken by the solid state imaging system from a distance of 1250 kilometers (750 miles).

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

Intrusive images and intrusive thoughts as different phenomena: two experimental studies.

PubMed

Hagenaars, Muriel A; Brewin, Chris R; van Minnen, Agnes; Holmes, Emily A; Hoogduin, Kees A L

2010-01-01

According to the dual representation theory of PTSD, intrusive trauma images and intrusive verbal thoughts are produced by separate memory systems. In a previous article it was shown that after watching an aversive film, participants in non-movement conditions reported more intrusive images than participants in a free-to-move control condition (Hagenaars, Van Minnen, Holmes, Brewin, & Hoogduin, 2008). The present study investigates whether the experimental conditions of the Hagenaars et al. study had a different effect on intrusive thoughts than on intrusive images. Experiment 2 further investigated the image-thoughts distinction by manipulating stimulus valence (trauma film versus neutral film) and assessing the subsequent development of intrusive images and thoughts. In addition, both experiments studied the impact of peri-traumatic emotions on subsequent intrusive images and thoughts frequency across conditions. Results showed that experimental manipulations (non-movement and trauma film) caused higher levels of intrusive images relative to control conditions (free movement and neutral film) but they did not affect intrusive thoughts. Peri-traumatic anxiety and horror were associated with subsequent higher levels of intrusive images, but not intrusive thoughts. Correlations were inconclusive for anger and sadness. The results suggest intrusive images and thoughts can be manipulated independently and as such can be considered different phenomena.

Dose to the contralateral breast: a comparison of two techniques using the enhanced dynamic wedge versus a standard wedge.

PubMed

Warlick, W B; O'Rear, J H; Earley, L; Moeller, J H; Gaffney, D K; Leavitt, D D

1997-01-01

The dose to the contralateral breast has been associated with an increased risk of developing a second breast malignancy. Varying techniques have been devised and described in the literature to minimize this dose. Metal beam modifiers such as standard wedges are used to improve the dose distribution in the treated breast, but unfortunately introduce an increased scatter dose outside the treatment field, in particular to the contralateral breast. The enhanced dynamic wedge is a means of remote wedging created by independently moving one collimator jaw through the treatment field during dose delivery. This study is an analysis of differing doses to the contralateral breast using two common clinical set-up techniques with the enhanced dynamic wedge versus the standard metal wedge. A tissue equivalent block (solid water), modeled to represent a typical breast outline, was designed as an insert in a Rando phantom to simulate a standard patient being treated for breast conservation. Tissue equivalent material was then used to complete the natural contour of the breast and to reproduce appropriate build-up and internal scatter. Thermoluminescent dosimeter (TLD) rods were placed at predetermined distances from the geometric beam's edge to measure the dose to the contralateral breast. A total of 35 locations were used with five TLDs in each location to verify the accuracy of the measured dose. The radiation techniques used were an isocentric set-up with co-planar, non divergent posterior borders and an isocentric set-up with a half beam block technique utilizing the asymmetric collimator jaw. Each technique used compensating wedges to optimize the dose distribution. A comparison of the dose to the contralateral breast was then made with the enhanced dynamic wedge vs. the standard metal wedge. The measurements revealed a significant reduction in the contralateral breast dose with the enhanced dynamic wedge compared to the standard metal wedge in both set-up techniques. The

Encasement and subsidence of salt minibasins: observations from the SE Precaspian Basin and numerical modeling.

NASA Astrophysics Data System (ADS)

Fernandez, Naiara; Duffy, Oliver B.; Hudec, Michael R.; Jackson, Christopher A.-L.; Dooley, Tim P.; Jackson, Martin P. A.; Burg, George

2017-04-01

The SE Precaspian Basin is characterized by an assemblage of Upper Permian to Triassic minibasins. A recently acquired borehole-constrained 3D reflection dataset reveals the existence of abundant intrasalt reflection packages lying in between the Permo-Triassic minibasins. We propose that most of the mapped intrasalt reflection packages in the study area are minibasins originally deposited on top of salt that were later incorporated into salt by encasement processes. This makes the SE Precaspian Basin a new example of a salt province populated by encased minibasins, which until now had been mainly described from the Gulf of Mexico. Identifying salt-encased sediment packages in the study area has been crucial, not only because they provide a new exploration target, but also because they can play a key role on improving seismic imaging of adjacent or deeper stratigraphic sections. Another remarkable feature observed in the seismic dataset is the widespread occurrence of distinct seismic sequences in the Permo-Triassic minibasins. Bowl- and wedge-shaped seismic sequences define discrete periods of vertical and asymmetric minibasin subsidence. In the absence of shortening, the bowl-to-wedge transition is typically associated with the timing of basal welding and subsequent rotation of the minibasins. Timing of minibasin welding has important implications when addressing the likelihood of suprasalt reservoir charging. We performed a set of 2D numerical simulations aimed at investigating what drives the tilting of minibasins and how it relates to welding. A key observation from the numerical models is that the bowl-to-wedge transition can predate the time of basal welding.

Substorm Current Wedge Revisited

NASA Astrophysics Data System (ADS)

Kepko, L.; McPherron, R. L.; Amm, O.; Apatenkov, S.; Baumjohann, W.; Birn, J.; Lester, M.; Nakamura, R.; Pulkkinen, T. I.; Sergeev, V.

2015-07-01

Almost 40 years ago the concept of the substorm current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during substorm expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced our understanding of this system. The AMPTE/IRM, THEMIS and Cluster missions have added considerable observational knowledge, especially on the important role of fast flows in producing the stresses that generate the substorm current wedge. Recent detailed, multi-spacecraft, multi-instrument observations both in the magnetosphere and in the ionosphere have brought a wealth of new information about the details of the temporal evolution and structure of the current system. While the large-scale picture remains valid, the new details call for revision and an update of the original view. In this paper we briefly review the historical development of the substorm current wedge, review recent in situ and ground-based observations and theoretical work, and discuss the current active research areas. We conclude with a revised, time-dependent picture of the substorm current wedge that follows its evolution from the initial substorm flows through substorm expansion and recovery.

Ice Particle Impacts on a Moving Wedge

NASA Technical Reports Server (NTRS)

Vargas, Mario; Struk, Peter M.; Kreeger, Richard E.; Palacios, Jose; Iyer, Kaushik A.; Gold, Robert E.

2014-01-01

This work presents the results of an experimental study of ice particle impacts on a moving wedge. The experiment was conducted in the Adverse Environment Rotor Test Stand (AERTS) facility located at Penn State University. The wedge was placed at the tip of a rotating blade. Ice particles shot from a pressure gun intercepted the moving wedge and impacted it at a location along its circular path. The upward velocity of the ice particles varied from 7 to 12 meters per second. Wedge velocities were varied from 0 to 120 meters per second. Wedge angles tested were 0 deg, 30 deg, 45 deg, and 60 deg. High speed imaging combined with backlighting captured the impact allowing observation of the effect of velocity and wedge angle on the impact and the post-impact fragment behavior. It was found that the pressure gun and the rotating wedge could be synchronized to consistently obtain ice particle impacts on the target wedge. It was observed that the number of fragments increase with the normal component of the impact velocity. Particle fragments ejected immediately after impact showed velocities higher than the impact velocity. The results followed the major qualitative features observed by other researchers for hailstone impacts, even though the reduced scale size of the particles used in the present experiment as compared to hailstones was 4:1.

Impingement of water droplets on wedges and double-wedge airfoils at supersonic speeds

NASA Technical Reports Server (NTRS)

Serafini, John S

1954-01-01

An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves. The results presented include the following conditions: droplet diameters from 2 to 100 microns, pressure altitudes from sea level to 30,000 feet, free-stream static temperatures from 420 degrees r, free stream Mach numbers from 1.1 to 2.0, semiapex angles for the wedge from 1.14 degrees to 7.97 degrees, thickness-to-chord ratios for the diamond airfoil from 0.02 to 0.14, chord lengths from 1 to 20 feet, and angles of attack from zero to the inverse tangent of the airfoil thickness-to-chord ratio.

Aerodynamic Analysis Over Double Wedge Airfoil

NASA Astrophysics Data System (ADS)

Prasad, U. S.; Ajay, V. S.; Rajat, R. H.; Samanyu, S.

2017-05-01

Aeronautical studies are being focused more towards supersonic flights and methods to attain a better and safer flight with highest possible performance. Aerodynamic analysis is part of the whole procedure, which includes focusing on airfoil shapes which will permit sustained flight of aircraft at these speeds. Airfoil shapes differ based on the applications, hence the airfoil shapes considered for supersonic speeds are different from the ones considered for Subsonic. The present work is based on the effects of change in physical parameter for the Double wedge airfoil. Mach number range taken is for transonic and supersonic. Physical parameters considered for the Double wedge case with wedge angle (ranging from 5 degree to 15 degree. Available Computational tools are utilized for analysis. Double wedge airfoil is analysed at different Angles of attack (AOA) based on the wedge angle. Analysis is carried out using fluent at standard conditions with specific heat ratio taken as 1.4. Manual calculations for oblique shock properties are calculated with the help of Microsoft excel. MATLAB is used to form a code for obtaining shock angle with Mach number and wedge angle at the given parameters. Results obtained from manual calculations and fluent analysis are cross checked.

Modelling of deformation around magmatic intrusions with application to gold-related structures in the Yilgarn Craton, Western Australia

NASA Astrophysics Data System (ADS)

Zhang, Y.; Karrech, A.; Schaubs, P. M.; Regenauer-Lieb, K.; Poulet, T.; Cleverley, J. S.

2012-03-01

This study simulates rock deformation around high temperature granite intrusions and explores how gold bearing shear zones near intrusions were developed in the Yilgarn, using a new continuum damage mechanics algorithm that considers the temperature and time dependent elastic-visco-plastic constitutive behaviour of crustal materials. The results demonstrate that strain rates have the most significant effects on structural patterns for both extensional and compressional cases. Smaller strain rates promote the formation of narrow high-strain shear zones and strong strain localisation along the flank or shoulder areas of the intrusion and cold granite dome. Wider diffuse shear zones are developed under higher strain rates due to strain hardening. The cooling of the intrusion to background temperatures occurred over a much shorter time interval when compared to the duration of deformation and shear zones development. Strong strain localisation near the intrusion and shear zone development in the crust occurred under both extensional and compressional conditions. There is always clear strain localisation around the shoulders of the intrusion and the flanks of the "cold" granitic dome in early deformation stages. In the models containing a pre-existing fault, strain localisation near the intrusion became asymmetric with much stronger localisation and the development of a damage zone at the shoulder adjacent to the reactivated fault. At higher deformation stages, the models produced a range of structural patterns including graben and half graben basin (extension), "pop-up" wedge structures (compression), tilted fault blocks and switch of shear movement from reverse to normal on shear zones. The model explains in part why a number of gold deposits (e.g. Wallaby and Paddington deposits) in the Yilgarn were formed near the flank of granite-cored domes and deep "tapping" faults, and shows that the new modelling approach is capable of realistically simulating high strain

Pressure Distributions About Finite Wedges in Bounded and Unbounded Subsonic Streams

NASA Technical Reports Server (NTRS)

Donoughe, Patrick L; Prasse, Ernst I

1953-01-01

An analytical investigation of incompressible flow about wedges was made to determine effects of tunnel-wedge ratio and wedge angle on the wedge pressure distributions. The region of applicability of infinite wedge-type velocity distribution was examined for finite wedges. Theoretical and experimental pressure coefficients for various tunnel-wedge ratios, wedge angles, and subsonic Mach numbers were compared.

Use of Wedge Absorbers in MICE

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

Neuffer, D.; Summers, D.; Mohayai, T.

2017-03-01

Wedge absorbers are needed to obtain longitudinal cooling in ionization cooling. They also can be used to obtain emittance exchanges between longitudinal and transverse phase space. There can be large exchanges in emittance, even with single wedges. In the present note we explore the use of wedge absorbers in the MICE experiment to obtain transverse–longitudinal emittance exchanges within present and future operational conditions. The same wedge can be used to explore “direct” and “reverse” emittance exchange dynamics, where direct indicates a configuration that reduces momentum spread and reverse is a configuration that increases momentum spread. Analytical estimated and ICOOL andmore » G4BeamLine simulations of the exchanges at MICE parameters are presented. Large exchanges can be obtained in both reverse and direct configurations.« less

Salt tectonics in an experimental turbiditic tank

NASA Astrophysics Data System (ADS)

Sellier, Nicolas; Vendeville, Bruno

2010-05-01

We modelled the effect of the deposition of clastic sediments wedges along passive margin by combining two different experimental approaches. The first approach, which uses flume experiments in order to model turbiditic transport and deposition, had focused, so far mainly on the stratigraphic architecture and flow properties. But most experiments have not accounted for the impact of syndepositional deformation. The second approach is the classic tectonic modelling (sand-box experiments) is aimed essentially at understanding deformation, for example the deformation of a sediment wedge deposited onto a mobile salt layer. However, with this approach, the sediment transport processes are crudely modelled by adding each sediment layer uniformly, regardless of the potential influence of the sea-floor bathymetry on the depositional pattern. We designed a new tectono-stratigraphic modelling tank, which combines modelling of the turbiditic transport and deposition, and salt-related deformation driven by sediment loading. The set-up comprises a channel connected to a main water tank. A deformation box is placed at the mouth of the channel, on the base of the tank. The base of the box can be filled with various kinds of substrates either rigid (sand) or viscous (silicone polymer, simulating mobile salt layer having varying length and thickness). A mixture of fine-grained powder and water is maintained in suspension in a container, and then released and channelled toward the basin, generating an analogue of basin-floor fans or lobes. We investigated the effect of depositing several consecutive turbiditic lobes on the deformation of the salt body and its overburden. The dynamics of experimental turbidity currents lead to deposits whose thickness varied gradually laterally: the lobe is thick in the proximal region and thins progressively distally, thus creating a very gentle regional surface slope. As the fan grows by episodic deposition of successive turbiditic lobes, the model

Wedges for ultrasonic inspection

DOEpatents

Gavin, Donald A.

1982-01-01

An ultrasonic transducer device is provided which is used in ultrasonic inspection of the material surrounding a threaded hole and which comprises a wedge of plastic or the like including a curved threaded surface adapted to be screwed into the threaded hole and a generally planar surface on which a conventional ultrasonic transducer is mounted. The plastic wedge can be rotated within the threaded hole to inspect for flaws in the material surrounding the threaded hole.

Ultrasonic transducer with laminated coupling wedge

DOEpatents

Karplus, Henry H. B.

1976-08-03

An ultrasonic transducer capable of use in a high-temperature environment incorporates a laminated metal coupling wedge including a reflecting edge shaped as a double sloping roof and a transducer crystal backed by a laminated metal sound absorber disposed so as to direct sound waves through the coupling wedge and into a work piece, reflections from the interface between the coupling wedge and the work piece passing to the reflecting edge. Preferably the angle of inclination of the two halves of the reflecting edge are different.

Capillary Rise in a Wedge

ERIC Educational Resources Information Center

Piva, M.

2009-01-01

In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

Distal Femoral Osteotomy for the Valgus Knee: Medial Closing Wedge Versus Lateral Opening Wedge: A Systematic Review.

PubMed

Wylie, James D; Jones, Daniel L; Hartley, Melissa K; Kapron, Ashley L; Krych, Aaron J; Aoki, Stephen K; Maak, Travis G

2016-10-01

(1) To determine the radiographic correction/healing rate, patient-reported outcomes, reoperation rate, and complication rate after distal femoral osteotomy (DFO) for the valgus knee with lateral compartment pathology. (2) To summarize the reported results of medial closing wedge and lateral opening wedge DFO. We conducted a systematic review of PubMed, MEDLINE, and CINAHL to identify studies reporting outcomes of DFOs for the valgus knee. Keywords included "distal femoral osteotomy," "chondral," "cartilage," "valgus," "joint restoration," "joint preservation," "arthritis," and "gonarthrosis." Two authors first reviewed the articles; our study exclusion criteria were then applied, and the articles were included on the basis relevance defined by the aforementioned criteria. The Methodological Index for Nonrandomized Studies scale judged the quality of the literature. Sixteen studies were relevant to the research questions out of 191 studies identified by the original search. Sixteen studies were identified reporting on 372 osteotomies with mean follow-up of 45 to 180 months. All studies reported mean radiographic correction to a near neutral mechanical axis, with 3.2% nonunion and 3.8% delayed union rates. There was a 9% complication rate and a 34% reoperation rate, of which 15% were converted to arthroplasty. There were similar results reported for medial closing wedge and lateral opening wedge techniques, with a higher conversion to arthroplasty in the medial closing wedge that was confounded by longer mean follow-up in this group (mean follow-up 100 v 58 months). DFOs for the valgus knee with lateral compartment disease provide improvements in patient-reported knee health-related quality of life at midterm follow-up but have high rates of reoperation. No evidence exists proving better results of either the lateral opening wedge or medial closing wedge techniques. Level IV, systematic review of Level IV studies. Copyright © 2016 Arthroscopy Association of North

Quality of water, Quillayute River basin, Washington

USGS Publications Warehouse

Fretwell, M.O.

1984-01-01

Groundwater in Quillayute River basin is generally of the calcium bicarbonate type, although water from some wells is affected by seawater intrusion and is predominantly of the sodium chloride type. The water is generally of excellent quality for most uses. River-water quality was generally excellent, as evaluated against Washington State water-use and water-quality criteria. Fecal coliform concentrations in all major tributaries met State water-quality criteria; water temperatures occasionally exceeded criteria maximum during periods of warm weather and low streamflow. Nutrient concentrations were generally low to very low. The four largest lakes in the basin were temperature-stratified in summer and one had an algal bloom. The Quillayute estuary had salt-wedge mixing characteristics; pollutants entering the salt wedge tended to spread to the toe of the wedge. Upwelling ocean water was the major cause of the low dissolved-oxygen concentrations observed in the estuary; ammonia concentrations in the estuary, however, were increased by the upwelling ocean waters. As in the rivers, total-coliform bacteria concentrations in the estuary were greater than fecal-coliform concentrations, indicating that many of the bacteria were of nonfecal origin and probably originated from soils. (USGS)

Scattering of In-Plane Waves by Elastic Wedges

NASA Astrophysics Data System (ADS)

Mohammadi, K.; Asimaki, D.; Fradkin, L.

2014-12-01

The scattering of seismic waves by elastic wedges has been a topic of interest in seismology and geophysics for many decades. Analytical, semi-analytical, experimental and numerical studies on idealized wedges have provided insight into the seismic behavior of continental margins, mountain roots and crustal discontinuities. Published results, however, have almost exclusively focused on incident Rayleigh waves and out-of-plane body (SH) waves. Complementing the existing body of work, we here present results from our study on the res­ponse of elastic wedges to incident P or SV waves, an idealized pro­blem that can provide valuable insight to the understanding and parameterization of topographic ampli­fication of seismic ground mo­tion. We first show our earlier work on explicit finite difference simulations of SV-wave scattering by elastic wedges over a wide range of internal angles. We next present a semi-analytical solution that we developed using the approach proposed by Gautesen, to describe the scattered wavefield in the immediate vicinity of the wedge's tip (near-field). We use the semi-analytical solution to validate the numerical analyses, and improve resolution of the amplification factor at the wedge vertex that spikes when the internal wedge angle approaches the critical angle of incidence.

Potential consequences of saltwater intrusion associated with Hurricanes Katrina and Rita: Chapter 6C in Science and the storms-the USGS response to the hurricanes of 2005

USGS Publications Warehouse

Steyer, Gregory D.; Perez, Brian C.; Piazza, Sarai C.; Suir, Glenn

2007-01-01

Hurricanes Katrina and Rita pushed salt water from the Gulf of Mexico well inland into freshwater marsh communities in coastal Louisiana. This paper describes the spatial extent of saltwater intrusion and provides an initial assessment of impacts (salt stress) to coastal marsh vegetation communities.

Chevron closing base wedge bunionectomy.

PubMed

Bruyn, J M

1993-01-01

The Chevron-base wedge Association for Osteosynthesis fixated bunionectomy provides a stable, aggressive correction of the severe hallux abducto valgus deformity. It is intended for the bunion requiring a double osteotomy in order to adequately reduce both intermetatarsal and proximal articular facet angle with minimal shortening and elevation. This article presents the rationale for the procedure, technique, and a 4-year follow-up of six patients with eight Chevron-base wedge bunionectomies.

Recirculating wedges for metal-vapor plasma tubes

DOEpatents

Hall, Jerome P.; Sawvel, Robert M.; Draggoo, Vaughn G.

1994-01-01

A metal vapor laser is disclosed that recycles condensed metal located at the terminal ends of a plasma tube back toward the center of the tube. A pair of arcuate wedges are incorporated on the bottom of the plasma tube near the terminal ends. The wedges slope downward toward the center so that condensed metal may be transported under the force of gravity away from the terminal ends. The wedges are curved to fit the plasma tube to thereby avoid forming any gaps within the tube interior.

Measuring Liquid-Level Utilizing Wedge Wave

PubMed Central

Honma, Yudai; Mori, Masayuki; Ihara, Ikuo

2017-01-01

A new technique for measuring liquid-level utilizing wedge wave is presented and demonstrated through FEM simulation and a corresponding experiment. The velocities of wedge waves in the air and the water, and the sensitivities for the measurement, are compared with the simulation and the results obtained in the experiments. Combining the simulation and the measurement theory, it is verified that the foundation framework for the methods is available. The liquid-level sensing is carried out using the aluminum waveguide with a 30° wedge in the water. The liquid-level is proportional to the traveling time of the mode 1 wedge wave. The standard deviations and the uncertainties of the measurement are 0.65 mm and 0.21 mm using interface echo, and 0.39 mm and 0.12 mm utilized by end echo, which are smaller than the industry standard of 1.5 mm. The measurement resolutions are 7.68 μm using the interface echo, which is the smallest among all the guided acoustic wave-based liquid-level sensing. PMID:29267232

Ultrasonic friction power during Al wire wedge-wedge bonding

NASA Astrophysics Data System (ADS)

Shah, A.; Gaul, H.; Schneider-Ramelow, M.; Reichl, H.; Mayer, M.; Zhou, Y.

2009-07-01

Al wire bonding, also called ultrasonic wedge-wedge bonding, is a microwelding process used extensively in the microelectronics industry for interconnections to integrated circuits. The bonding wire used is a 25μm diameter AlSi1 wire. A friction power model is used to derive the ultrasonic friction power during Al wire bonding. Auxiliary measurements include the current delivered to the ultrasonic transducer, the vibration amplitude of the bonding tool tip in free air, and the ultrasonic force acting on the bonding pad during the bond process. The ultrasonic force measurement is like a signature of the bond as it allows for a detailed insight into mechanisms during various phases of the process. It is measured using piezoresistive force microsensors integrated close to the Al bonding pad (Al-Al process) on a custom made test chip. A clear break-off in the force signal is observed, which is followed by a relatively constant force for a short duration. A large second harmonic content is observed, describing a nonsymmetric deviation of the signal wave form from the sinusoidal shape. This deviation might be due to the reduced geometrical symmetry of the wedge tool. For bonds made with typical process parameters, several characteristic values used in the friction power model are determined. The ultrasonic compliance of the bonding system is 2.66μm/N. A typical maximum value of the relative interfacial amplitude of ultrasonic friction is at least 222nm. The maximum interfacial friction power is at least 11.5mW, which is only about 4.8% of the total electrical power delivered to the ultrasonic generator.

Recirculating wedges for metal-vapor plasma tubes

DOEpatents

Hall, J.P.; Sawvel, R.M.; Draggoo, V.G.

1994-06-28

A metal vapor laser is disclosed that recycles condensed metal located at the terminal ends of a plasma tube back toward the center of the tube. A pair of arcuate wedges are incorporated on the bottom of the plasma tube near the terminal ends. The wedges slope downward toward the center so that condensed metal may be transported under the force of gravity away from the terminal ends. The wedges are curved to fit the plasma tube to thereby avoid forming any gaps within the tube interior. 8 figures.

Seamount subduction underneath an accretionary wedge: modelling mass wasting and wedge collapse

NASA Astrophysics Data System (ADS)

Mannu, Utsav; Ueda, Kosuke; Willett, Sean; Gerya, Taras; Strasser, Michael

2017-04-01

Seamounts (h >1 km) and knolls (h = 500 m-1000 m) cover about one-fifth of the total ocean floor area. These topographical highs of the ocean floor eventually get subducted. Subduction of these topographical features leads to severe deformation of the overriding plate and can cause extensive tectonic erosion and mass wasting of the frontal prism, which can ultimately cause a forearc wedge collapse. Large submarine landslides and the corresponding wedge collapse have previously been reported, for instance, in the northern part of the Hikurangi margin where the landslide is known as the giant Ruatoria debris avalanche, and have also been frequently reported in several seismic sections along the Costa Rica margin. Size and frequency relation of landslides suggest that the average size of submarine landslides in margins with rough subducting plates tends to be larger. However, this observation has not yet been tested or explained by physical models. In numerical subduction models, landslides take place, if at all, on a much larger timescale (in the order of 104-105 years, depending on the time steps of the model) than in natural cases. On the other hand, numerical models simulating mass wasting events such as avalanches and submarine landslides, typically model single events at a much smaller spatio-temporal domain, and do not consider long-term occurrence patterns of freely forming landslides. In this contribution, we present a multi-scale nested numerical approach to emulate short-term landslides within long-term progressive subduction. The numerical approach dynamically produces instantaneous submarine landslides and the resulting debris flow in the spatially and temporally refined inner model. Then we apply these convoluted changes in topography (e.g. due to the submarine landslide etc.) back to an outer larger-scale model instance that addresses wedge evolution. We use this approach to study the evolution of the accretionary wedge during seamount subduction.

Ancient Yedoma carbon loss: primed by ice wedge thaw?

NASA Astrophysics Data System (ADS)

Dowdy, K. L.; Vonk, J. E.; Mann, P. J.; Zimov, N.; Bulygina, E. B.; Davydova, A.; Spencer, R. G.; Holmes, R. M.

2012-12-01

Northeast Siberian permafrost is dominated by frozen Yedoma deposits containing ca. 500 Gt of carbon, nearly a quarter of northern permafrost organic carbon (OC). Yedoma deposits are Pleistocene-age alluvial and/or aeolian accumulations characterized by high ice wedge content (~50%), making them particularly vulnerable to a warming climate and to surface collapse upon thaw. Dissolved OC in streams originating primarily from Yedoma has been shown to be highly biolabile, relative to waters containing more modern OC. The cause of this biolability, however, remains speculative. Here we investigate the influence of ice wedge input upon the bioavailability of Yedoma within streams from as a potential cause of Yedoma carbon biolability upon release into the Kolyma River from the thaw-eroding river exposures of Duvannyi Yar, NE Siberia. We measured biolability on (1) ice wedge, Kolyma, and Yedoma leachate controls; (2) ice wedge and Kolyma plus Yedoma OC (8 g/L); and (3) varying ratios of ice wedge water to Kolyma river water. Biolability assays were conducted using both 5-day BOD (biological oxygen demand) and 11-day BDOC (biodegradable dissolved organic carbon) incubations. We found that ancient DOC in Yedoma soil leachate alone was highly biolabile with losses of 52±0.1% C over a 5-day BOD incubation. Similarly, DOC contained in pure ice wedge water was found to be biolabile, losing 21±0% C during a 5-day BOD incubation. Increased ice wedge contributions led to higher overall C losses in identical Yedoma soil leachates, with 8.9±0.6% losses of Yedoma C with 100% ice wedge water, 7.1±1% (50% ice wedge/ 50% Kolyma) and 5±0.3% with 100% Kolyma River water. We discuss potential mechanisms for the increased loss of ancient C using associated measurements of nutrient availability, carbon quality (CDOM/FDOM) and extracellular enzyme activity rates. Our initial results indicate that ice wedge meltwater forming Yedoma streams makes Yedoma OC more bioavailable than it would

The challenges of numerically simulating analogue brittle thrust wedges

NASA Astrophysics Data System (ADS)

Buiter, Susanne; Ellis, Susan

2017-04-01

Fold-and-thrust belts and accretionary wedges form when sedimentary and crustal rocks are compressed into thrusts and folds in the foreland of an orogen or at a subduction trench. For over a century, analogue models have been used to investigate the deformation characteristics of such brittle wedges. These models predict wedge shapes that agree with analytical critical taper theory and internal deformation structures that well resemble natural observations. In a series of comparison experiments for thrust wedges, called the GeoMod2004 (1,2) and GeoMod2008 (3,4) experiments, it was shown that different numerical solution methods successfully reproduce sandbox thrust wedges. However, the GeoMod2008 benchmark also pointed to the difficulties of representing frictional boundary conditions and sharp velocity discontinuities with continuum numerical methods, in addition to the well-known challenges of numerical plasticity. Here we show how details in the numerical implementation of boundary conditions can substantially impact numerical wedge deformation. We consider experiment 1 of the GeoMod2008 brittle thrust wedge benchmarks. This experiment examines a triangular thrust wedge in the stable field of critical taper theory that should remain stable, that is, without internal deformation, when sliding over a basal frictional surface. The thrust wedge is translated by lateral displacement of a rigid mobile wall. The corner between the mobile wall and the subsurface is a velocity discontinuity. Using our finite-element code SULEC, we show how different approaches to implementing boundary friction (boundary layer or contact elements) and the velocity discontinuity (various smoothing schemes) can cause the wedge to indeed translate in a stable manner or to undergo internal deformation (which is a fail). We recommend that numerical studies of sandbox setups not only report the details of their implementation of boundary conditions, but also document the modelling attempts that

Effect of a trade between boattail angle and wedge size on the performance of a nonaxisymmetric wedge nozzle

NASA Technical Reports Server (NTRS)

Carson, George T., Jr.; Bare, E. Ann; Burley, James R., II

1987-01-01

An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the effect of a boattail angle and wedge-size trade on the performance of nonaxisymmetric wedge nozzles installed on a generic twin-engine fighter aircraft model. Test data were obtained at static conditions and at Mach numbers from 0.60 to 1.25. Angle of attack was held constant at 0 deg. High-pressure air was used to simulate jet exhaust, and the nozzle pressure ratio was varied from 1.0 (jet off) to slightly over 15.0. For the configurations studied, the results indicate that wedge size can be reduced without affecting aeropropulsive performance.

Periodic nanostructures from self assembled wedge-type block-copolymers

DOEpatents

Xia, Yan; Sveinbjornsson, Benjamin R.; Grubbs, Robert H.; Weitekamp, Raymond; Miyake, Garret M.; Piunova, Victoria; Daeffler, Christopher Scot

2015-06-02

The invention provides a class of wedge-type block copolymers having a plurality of chemically different blocks, at least a portion of which incorporates a wedge group-containing block providing useful properties. For example, use of one or more wedge group-containing blocks in some block copolymers of the invention significantly inhibits chain entanglement and, thus, the present block copolymers materials provide a class of polymer materials capable of efficient molecular self-assembly to generate a range of structures, such as periodic nanostructures and microstructures. Materials of the present invention include copolymers having one or more wedge group-containing blocks, and optionally for some applications copolymers also incorporating one or more polymer side group-containing blocks. The present invention also provides useful methods of making and using wedge-type block copolymers.

Group sequential designs for stepped-wedge cluster randomised trials.

PubMed

Grayling, Michael J; Wason, James Ms; Mander, Adrian P

2017-10-01

The stepped-wedge cluster randomised trial design has received substantial attention in recent years. Although various extensions to the original design have been proposed, no guidance is available on the design of stepped-wedge cluster randomised trials with interim analyses. In an individually randomised trial setting, group sequential methods can provide notable efficiency gains and ethical benefits. We address this by discussing how established group sequential methodology can be adapted for stepped-wedge designs. Utilising the error spending approach to group sequential trial design, we detail the assumptions required for the determination of stepped-wedge cluster randomised trials with interim analyses. We consider early stopping for efficacy, futility, or efficacy and futility. We describe first how this can be done for any specified linear mixed model for data analysis. We then focus on one particular commonly utilised model and, using a recently completed stepped-wedge cluster randomised trial, compare the performance of several designs with interim analyses to the classical stepped-wedge design. Finally, the performance of a quantile substitution procedure for dealing with the case of unknown variance is explored. We demonstrate that the incorporation of early stopping in stepped-wedge cluster randomised trial designs could reduce the expected sample size under the null and alternative hypotheses by up to 31% and 22%, respectively, with no cost to the trial's type-I and type-II error rates. The use of restricted error maximum likelihood estimation was found to be more important than quantile substitution for controlling the type-I error rate. The addition of interim analyses into stepped-wedge cluster randomised trials could help guard against time-consuming trials conducted on poor performing treatments and also help expedite the implementation of efficacious treatments. In future, trialists should consider incorporating early stopping of some kind into

P-Wave to Rayleigh-wave conversion coefficients for wedge corners; model experiments

USGS Publications Warehouse

Gangi, A.F.; Wesson, R.L.

1978-01-01

An analytic solution is not available for the diffraction of elastic waves by wedges; however, numerical solutions of finite-difference type are available for selected wedge angles. The P- to Rayleigh-wave conversion coefficients at wedge tips have been measured on two-dimensional seismic models for stress-free wedges with wedge angles, ??0, of 10, 30, 60, 90 and 120??. The conversion coefficients show two broad peaks and a minimum as a function of the angle between the wedge face and the direction of the incident P-wave. The minimum occurs for the P wave incident parallel to the wedge face and one maximum is near an incidence angle of 90?? to the wedge face. The amplitude of this maximum, relative to the other, decreases as the wedge angle increases. The asymmetry of the conversion coefficients, CPR(??; ??0), relative to parallel incidence (?? = 0) increases as the wedge angle increases. The locations of the maxima and the minimum as well as the asymmetry can be explained qualitatively. The conversion coefficients are measured with an accuracy of ??5% in those regions where there are no interfering waves. A comparison of the data for the 10?? wedge with the theoretical results for a half plane (0?? wedge) shows good correlation. ?? 1978.

Ice Wedges as Winter Climate Archives - New Results from the Northeast Siberian Arctic and Discussion of the Paleoclimatic Value of Ice Wedges

NASA Astrophysics Data System (ADS)

Opel, T.; Meyer, H.; Laepple, T.; Rehfeld, K.; Mollenhauer, G.; Alexander, D.; Murton, J.

2017-12-01

Arctic climate has experienced major changes over the past millennia that are yet not fully understood in terms of external and internal controls, spatial, temporal, and seasonal patterns. The interpretation of stable isotope data in permafrost ice wedges provides unique information on past winter climate, not or not sufficiently captured by other Arctic climate archives. Ice wedges grow in polygonal patterns owing to frost cracking of the frozen ground in winter and frost-crack filling mostly by snowmelt in spring. Their oxygen isotope values are indicative of temperatures in the cold period of the year (meteorological winter and spring). Recently, an ice-wedge record from the Lena River Delta suggested for the first time, that Siberian winter temperatures were warming throughout the Holocene, contradicting most other Arctic paleoclimate reconstructions. As this was based on a single record, the representativity and spatial extent of the reconstructed winter warming signal remained unclear. In this two-part contribution, we first present a new ice-wedge δ18O record from the Oyogos Yar mainland coast (Northeast Siberian Arctic) and then discuss more generally the paleoclimatic value of ice wedges. The new Oyogos Yar ice-wedge record is based on paired stable-isotope and radiocarbon-age data and spans the last two millennia. It confirms the long-term winter warming signal as well as the unprecedented temperature rise in the last decades. This demonstrates that winter warming over the last millennia is a coherent feature in the Northeastern Siberian Arctic, supporting the hypothesis of an insolation-driven seasonal Holocene temperature evolution followed by a strong warming most likely related to anthropogenic forcing. Considering additional ice-wedge data from the Siberian Laptev Sea region we discuss the paleoclimatic value of ice wedges as high-quality winter climate archive. We assess potentials and challenges of this so far rather understudied source of

Spatiotemporal variation of Van der Burgh's coefficient in a salt plug estuary

NASA Astrophysics Data System (ADS)

Shaha, Dinesh Chandra; Cho, Yang-Ki; Kim, Bong Guk; Rafi Afruz Sony, M.; Rani Kundu, Sampa; Faruqul Islam, M.

2017-09-01

Salt water intrusion in estuaries is expected to become a serious global issue due to climate change. Van der Burgh's coefficient, K, is a good proxy for describing the relative contribution of tide-driven and gravitational (discharge-driven and density-driven) components of salt transport in estuaries. However, debate continues over the use of the K value for an estuary where K should be a constant, spatially varying, or time-independent factor for different river discharge conditions. In this study, we determined K during spring and neap tides in the dry (< 30 m-3 s-1) and wet (> 750 m-3 s-1) seasons in a salt plug estuary with an exponentially varying width and depth, to examine the relative contributions of tidal versus density-driven salt transport mechanisms. High-resolution salinity data were used to determine K. Discharge-driven gravitational circulation (K ˜ 0.8) was entirely dominant over tidal dispersion during spring and neap tides in the wet season, to the extent that salt transport upstream was effectively reduced, resulting in the estuary remaining in a relatively fresh state. In contrast, K increased gradually seaward (K ˜ 0.74) and landward (K ˜ 0.74) from the salt plug area (K ˜ 0.65) during the dry season, similar to an inverse and positive estuary, respectively. As a result, density-driven inverse gravitational circulation between the salt plug and the sea facilitates inverse estuarine circulation. On the other hand, positive estuarine circulation between the salt plug and the river arose due to density-driven positive gravitational circulation during the dry season, causing the upstream intrusion of high-salinity bottom water. Our results explicitly show that K varies spatially and depends on the river discharge. This result provides a better understanding of the distribution of hydrographic properties.

Assessment of Effectiveness of Geologic Isolation Systems: REFERENCE SITE INITIAL ASSESSMENT FOR A SALT DOME REPOSITORY

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

Harwell, M. A.; Brandstetter, A.; Benson, G. L.

1982-06-01

As a methodology demonstration for the Office of Nuclear Waste Isolation (ONWI), the Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program conducted an initial reference site analysis of the long-term effectiveness of a salt dome repository. The Hainesville Salt Dome in Texas was chosen to be representative of the Gulf Coast interior salt domes; however, the Hainesville Site has been eliminated as a possible nuclear waste repository site. The data used for this exercise are not adequate for an actual assessment, nor have all the parametric analyses been made that would adequately characterize the response of the geosystem surroundingmore » the repository. Additionally, because this was the first exercise of the complete AEGIS and WASTE Rock Interaction Technology (WRIT) methodology, this report provides the initial opportunity for the methodology, specifically applied to a site, to be reviewed by the community outside the AEGIS. The scenario evaluation, as a part of the methodology demonstration, involved consideration of a large variety of potentially disruptive phenomena, which alone or in concert could lead to a breach in a salt dome repository and to a subsequent transport of the radionuclides to the environment. Without waste- and repository-induced effects, no plausible natural geologic events or processes which would compromise the repository integrity could be envisioned over the one-million-year time frame after closure. Near-field (waste- and repository-induced) effects were excluded from consideration in this analysis, but they can be added in future analyses when that methodology development is more complete. The potential for consequential human intrusion into salt domes within a million-year time frame led to the consideration of a solution mining intrusion scenario. The AEGIS staff developed a specific human intrusion scenario at 100 years and 1000 years post-closure, which is one of a whole suite of possible scenarios. This

Assessment of Effectiveness of Geologic Isolation Systems: REFERENCE SITE INITIAL ASSESSMENT FOR A SALT DOME REPOSITORY

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

Harwell, M. A.; Brandstetter, A.; Benson, G. L.

1982-06-01

As a methodology demonstration for the Office of Nuclear Waste Isolation (ONWI), the Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program conducted an initial reference site analysis of the long-term effectiveness of a salt dome repository. The Hainesville Salt Dome in Texas was chosen to be representative of the Gulf Coast interior salt domes; however, the Hainesville Site has been eliminated as a possible nuclear waste repository site. The data used for this exercise are not adequate for an actual assessment, nor have all the parametric analyses been made that would adequately characterize the response of the geosystem surroundingmore » the repository. Additionally, because this was the first exercise of the complete AEGIS and WASTE Rock Interaction Technology (WRIT) methodology, this report provides the initial opportunity for the methodology, specifically applied to a site, to be reviewed by the community outside the AEGIS. The scenario evaluation, as a part of the methodology demonstration, involved consideration of a large variety of potentially disruptive phenomena, which alone or in concert could lead to a breach in a salt dome repository and to a subsequent transport of the radionuclides to the environment. Without waste- and repository-induced effects, no plausible natural geologic events or processes which would compromise the repository integrity could be envisioned over the one-million-year time frame after closure. Near-field (waste- and repository-induced) effects were excluded from consideration in this analysis, but they can be added in future analyses when that methodology development is more complete. The potential for consequential human intrusion into salt domes within a million-year time frame led to the consideration of a solution mining intrusion scenario. The AEGIS staff developed a specific human intrusion scenario at 100 years and 1000 years post-closure, which is one of a whole suite of possible scenarios. This

Petroleum Vapor Intrusion

EPA Pesticide Factsheets

One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

Study on the shock interference in a wedged convergent-divergent channel

NASA Astrophysics Data System (ADS)

Yu, F. M.; Wang, C. Z.

The investigation of shock reflection-to-diffraction phenomena upon a wedged convergent-divergent channel produced by a planar incident shock wave have been done in the shock tube facility of Institute of Aeronautics and Astronautics, National Cheng-Kung University. The experiment proceeds upon seven wedged convergent-divergent channels with the forward and rear wedge angles arrangement of them are (50°, 50°), (35°, 35°), (50°, 35°), (35°, 50°), (50°, 0°), (35°, 0°), and (90°, 0°), respectively. They were tested at Mach numbers of 1.1, 1.2, 1.3, 1.4, 1.5 and 1.6, respectively. On the first wedged channel, following the regular reflection on a 50°- wedged surface by the incident shock wave, shock diffraction with Mach stem has been observed as it moves to the downstream wedge surface. On the apex of the wedge, the secondary reflected shock behaviors as a sector of the blast shock moving toward the centerline of the channel. From the color schlieren pictures it has been observed that there exists a pattern of blast-wave-type high gas density gradient region near the wedge apex. Following the Mach reflection from the 35° -wedged surface on which only the Mach stem diffracted across the apex and following with a small region of disturbed acoustic wave front. The shock interference, which proceeds by the Mach reflection-to-diffraction generates a very complicate vortical flow structure. The measurement of the peak pressure along centerline of the channel downstream of the wedge apex indicates that it is larger near the apex and it decreases downstream. It is larger for larger convergent wedge angle and It is smaller for larger divergent wedge angle.

Microtopographic control on the ground thermal regime in ice wedge polygons

NASA Astrophysics Data System (ADS)

Abolt, Charles J.; Young, Michael H.; Atchley, Adam L.; Harp, Dylan R.

2018-06-01

The goal of this research is to constrain the influence of ice wedge polygon microtopography on near-surface ground temperatures. Ice wedge polygon microtopography is prone to rapid deformation in a changing climate, and cracking in the ice wedge depends on thermal conditions at the top of the permafrost; therefore, feedbacks between microtopography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of sub-daily ground temperature observations at 5 depths and 9 locations throughout a cluster of low-centered polygons near Prudhoe Bay, Alaska, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.1 °C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs and tracking the effects on ice wedge temperature. The results indicate that winter temperatures in the ice wedge are sensitive to both rim height and trough depth, but more sensitive to rim height. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. Deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for re-establishing rims in modern thermokarst-affected terrain will be limited by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize.

Intrusion-aware alert validation algorithm for cooperative distributed intrusion detection schemes of wireless sensor networks.

PubMed

Shaikh, Riaz Ahmed; Jameel, Hassan; d'Auriol, Brian J; Lee, Heejo; Lee, Sungyoung; Song, Young-Jae

2009-01-01

Existing anomaly and intrusion detection schemes of wireless sensor networks have mainly focused on the detection of intrusions. Once the intrusion is detected, an alerts or claims will be generated. However, any unidentified malicious nodes in the network could send faulty anomaly and intrusion claims about the legitimate nodes to the other nodes. Verifying the validity of such claims is a critical and challenging issue that is not considered in the existing cooperative-based distributed anomaly and intrusion detection schemes of wireless sensor networks. In this paper, we propose a validation algorithm that addresses this problem. This algorithm utilizes the concept of intrusion-aware reliability that helps to provide adequate reliability at a modest communication cost. In this paper, we also provide a security resiliency analysis of the proposed intrusion-aware alert validation algorithm.

Numerical study on dusty shock reflection over a double wedge

NASA Astrophysics Data System (ADS)

Yin, Jingyue; Ding, Juchun; Luo, Xisheng

2018-01-01

The dusty shock reflection over a double wedge with different length scales is systematically studied using an adaptive multi-phase solver. The non-equilibrium effect caused by the particle relaxation is found to significantly influence the shock reflection process. Specifically, it behaves differently for double wedges with different length scales of the first wedge L1. For a double wedge with L1 relatively longer than the particle relaxation length λ, the equilibrium shock dominates the shock reflection and seven typical reflection processes are obtained, which is similar to the pure gas counterpart. For a double wedge with L1 shorter than λ, the non-equilibrium effect manifests more evidently, i.e., three parts of the dusty shock system including the frozen shock, the relaxation zone, and the equilibrium shock together dominate the reflection process. As a result, the shock reflection is far more complicated than the pure gas counterpart and eleven transition processes are found under various wedge angles. These findings give a complete description of all possible processes of dusty shock reflection over a double wedge and may be useful for better understanding the non-equilibrium shock reflection over complex structures.

The Substorm Current Wedge Revisited

NASA Astrophysics Data System (ADS)

Kepko, Larry; McPherron, Robert; Apatenkov, Sergey; Baumjohann, Wolfgang; Birn, Joachim; Lester, Mark; Nakamura, Rumi; Pulkkinen, Tuija; Sergeev, Victor

2015-04-01

Almost 40 years ago the concept of the substorm current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during substorm expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced our understanding of this system. The AMPTE/IRM, THEMIS and Cluster missions have added considerable observational knowledge, especially on the important role of fast flows in producing the stresses that generate the substorm current wedge. Recent detailed, multi-spacecraft, multi-instrument observations both in the magnetosphere and in the ionosphere have brought a wealth of new information about the details of the temporal evolution and structure of the current system. In this paper, we briefly review recent in situ and ground-based observations and theoretical work that have demonstrated a need for an update of the original picture. We present a revised, time-dependent picture of the substorm current wedge that follows its evolution from the initial substorm flows through substorm expansion and recovery, and conclude by identifying open questions.

Experimental investigation of sound absorption of acoustic wedges for anechoic chambers

NASA Astrophysics Data System (ADS)

Belyaev, I. V.; Golubev, A. Yu.; Zverev, A. Ya.; Makashov, S. Yu.; Palchikovskiy, V. V.; Sobolev, A. F.; Chernykh, V. V.

2015-09-01

The results of measuring the sound absorption by acoustic wedges, which were performed in AC-3 and AC-11 reverberation chambers at the Central Aerohydrodynamic Institute (TsAGI), are presented. Wedges of different densities manufactured from superfine basaltic and thin mineral fibers were investigated. The results of tests of these wedges were compared to the sound absorption of wedges of the operating AC-2 anechoic facility at TsAGI. It is shown that basaltic-fiber wedges have better sound-absorption characteristics than the investigated analogs and can be recommended for facing anechoic facilities under construction.

Intrusion-Aware Alert Validation Algorithm for Cooperative Distributed Intrusion Detection Schemes of Wireless Sensor Networks

PubMed Central

Shaikh, Riaz Ahmed; Jameel, Hassan; d’Auriol, Brian J.; Lee, Heejo; Lee, Sungyoung; Song, Young-Jae

2009-01-01

Existing anomaly and intrusion detection schemes of wireless sensor networks have mainly focused on the detection of intrusions. Once the intrusion is detected, an alerts or claims will be generated. However, any unidentified malicious nodes in the network could send faulty anomaly and intrusion claims about the legitimate nodes to the other nodes. Verifying the validity of such claims is a critical and challenging issue that is not considered in the existing cooperative-based distributed anomaly and intrusion detection schemes of wireless sensor networks. In this paper, we propose a validation algorithm that addresses this problem. This algorithm utilizes the concept of intrusion-aware reliability that helps to provide adequate reliability at a modest communication cost. In this paper, we also provide a security resiliency analysis of the proposed intrusion-aware alert validation algorithm. PMID:22454568

Group sequential designs for stepped-wedge cluster randomised trials

PubMed Central

Grayling, Michael J; Wason, James MS; Mander, Adrian P

2017-01-01

Background/Aims: The stepped-wedge cluster randomised trial design has received substantial attention in recent years. Although various extensions to the original design have been proposed, no guidance is available on the design of stepped-wedge cluster randomised trials with interim analyses. In an individually randomised trial setting, group sequential methods can provide notable efficiency gains and ethical benefits. We address this by discussing how established group sequential methodology can be adapted for stepped-wedge designs. Methods: Utilising the error spending approach to group sequential trial design, we detail the assumptions required for the determination of stepped-wedge cluster randomised trials with interim analyses. We consider early stopping for efficacy, futility, or efficacy and futility. We describe first how this can be done for any specified linear mixed model for data analysis. We then focus on one particular commonly utilised model and, using a recently completed stepped-wedge cluster randomised trial, compare the performance of several designs with interim analyses to the classical stepped-wedge design. Finally, the performance of a quantile substitution procedure for dealing with the case of unknown variance is explored. Results: We demonstrate that the incorporation of early stopping in stepped-wedge cluster randomised trial designs could reduce the expected sample size under the null and alternative hypotheses by up to 31% and 22%, respectively, with no cost to the trial’s type-I and type-II error rates. The use of restricted error maximum likelihood estimation was found to be more important than quantile substitution for controlling the type-I error rate. Conclusion: The addition of interim analyses into stepped-wedge cluster randomised trials could help guard against time-consuming trials conducted on poor performing treatments and also help expedite the implementation of efficacious treatments. In future, trialists should

Hydrogeology and extent of saltwater intrusion of the Great Neck peninsula, Great Neck, Long Island, New York

USGS Publications Warehouse

Stumm, Frederick

2001-01-01

-southeast, (4) are 2-4 miles long and about 1 mile wide, and (5) extend to more than 200 feet below sea level.Water from six public-supply wells screened in the Magothy and upper glacial aquifers contained volatile organic compounds in concentrations above the New York State Department of Health Drinking Water Maximum Contaminant Levels, as did water from one public-supply well screened in the Lloyd aquifer, and from three observation wells screened in the upper glacial and Magothy aquifers.Four distinct wedge-shaped areas of saltwater intrusion have been delineated within the aquifers in Great Neck; three areas extend into the Lloyd and North Shore aquifers, and the fourth area extends into the upper glacial aquifer. Three other areas of saltwater intrusion also have been detected. Borehole-geophysical-logging data indicate that four of these saltwater wedges range from 20 to 125 feet in thickness and have sharp freshwater-saltwater interfaces, and that maximum chloride concentrations in 1996 ranged from 141 to 13,750 milligrams per liter. Seven public-supply wells have either been shut down or are currently being affected by saltwater intrusion.

Isolating active orogenic wedge deformation in the southern Subandes of Bolivia

NASA Astrophysics Data System (ADS)

Weiss, Jonathan R.; Brooks, Benjamin A.; Foster, James H.; Bevis, Michael; Echalar, Arturo; Caccamise, Dana; Heck, Jacob; Kendrick, Eric; Ahlgren, Kevin; Raleigh, David; Smalley, Robert; Vergani, Gustavo

2016-08-01

A new GPS-derived surface velocity field for the central Andean backarc permits an assessment of orogenic wedge deformation across the southern Subandes of Bolivia, where recent studies suggest that great earthquakes (>Mw 8) are possible. We find that the backarc is not isolated from the main plate boundary seismic cycle. Rather, signals from subduction zone earthquakes contaminate the velocity field at distances greater than 800 km from the Chile trench. Two new wedge-crossing velocity profiles, corrected for seasonal and earthquake affects, reveal distinct regions that reflect (1) locking of the main plate boundary across the high Andes, (2) the location of and loading rate at the back of orogenic wedge, and (3) an east flank velocity gradient indicative of décollement locking beneath the Subandes. Modeling of the Subandean portions of the profiles indicates along-strike variations in the décollement locked width (WL) and wedge loading rate; the northern wedge décollement has a WL of ~100 km while accumulating slip at a rate of ~14 mm/yr, whereas the southern wedge has a WL of ~61 km and a slip rate of ~7 mm/yr. When compared to Quaternary estimates of geologic shortening and evidence for Holocene internal wedge deformation, the new GPS-derived wedge loading rates may indicate that the southern wedge is experiencing a phase of thickening via reactivation of preexisting internal structures. In contrast, we suspect that the northern wedge is undergoing an accretion or widening phase primarily via slip on relatively young thrust-front faults.

A Wedge Absorber Experiment at MICE

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

Neuffer, David; Mohayai, Tanaz; Rogers, Chris

2017-05-01

Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

Planar shock reflection on a wedged concave reflector

NASA Astrophysics Data System (ADS)

Yu, Fan-Ming; Sheu, Kuen-Dong

2001-04-01

The investigation of shock reflection and shock diffraction phenomena upon a wedged concave reflector produced by a planar incident shock wave has been done in the shock tube facility of Institute of Aeronautics and Astronautics, National Cheng- Kung University. The experiment proceeds upon three wedged concave reflectors models the upper and lower wedge angles arrangement of them are (50 degrees, 50 degrees) - 35 degrees, 35 degrees) and (50 degrees, 35 degrees), respectively. They were tested at Mach numbers of 1.2 - 1.65 and 2.0. On the first reflector, following the regular reflection on the 50 degree-wedged surface by the incident shock wave, a Mach shock diffraction behavior has been observed as shock moves outward from the apex of the reflector. On the apex of the reflector, it behaviors as a sector of the blast shock moving on a diverging channel. On the shadowgraph pictures it has been observed there exists a pattern of gas dynamics focus upon the second reflector. The Mach reflection from the 35 degree- wedged surface as being generated by the planar incident shock wave, on which the overlapping of the two triple points from both wedged surface offers the focusing mechanism. The shock interference, which proceeds by the Mach shock reflection and the regular shock diffraction from the reflector, generates a very complicate rolling-up of slip lines system. On the third reflector, the mixed shock interference behavior has been observed of which two diffraction shocks from concave 50 degree-wedged surface and 35 degree-wedged surface interfere with each other. The measurement of the peak pressure along a ray from the model apex parallel to incident shock direction indicates that the measured maximum pressure rising is larger near the apex of the reflector. Considering the measured maximum pressure increment due to the reflection shocks indicate that the wave strength upon large apex angle reflector is greater than it is upon small apex angle reflector

Present and future challenges of urban systems affected by seawater and its intrusion: the case of Venice, Italy

NASA Astrophysics Data System (ADS)

di Sipio, Eloisa; Zezza, Fulvio

2011-11-01

In lagoonal and marine environments, both historic monuments and recent buildings suffer from severe salt damage caused by sea flooding, sea-level rise and frequent storm events. Salt-water contamination of groundwater systems, a widespread phenomenon typical of coastal areas, can lead to a deterioration not only of the quality of fresh groundwater resources, but also of building materials in urban settlements. A general overview is given of the hydrogeological configuration of the subsoil of Venice (Italy), with particular reference to the shallow groundwater circulation. The relationship between the seawater in the subsoil and salt decay processes, due to salt crystallization, is highlighted. These processes affect civil constructions in Venice's historic center. Perched aquifers, influenced by tide variations and characterized by salt-water intrusion, favor the transport of salts within masonry walls through the action of rising damp. In fact, foundations, in direct contact with the aquifers, may become a preferential vehicle for the transportation of salt within buildings. Decay patterns of different building materials can be detected through non-destructive techniques, which can identify sea-salt damage and therefore assist in the preservation of cultural heritage in coastal areas.

21 CFR 884.5200 - Hemorrhoid prevention pressure wedge.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hemorrhoid prevention pressure wedge. 884.5200... Devices § 884.5200 Hemorrhoid prevention pressure wedge. (a) Identification. A hemorrhoid prevention... hemorrhoids associated with vaginal childbirth. (b) Classification. Class II (special controls). The special...

21 CFR 884.5200 - Hemorrhoid prevention pressure wedge.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hemorrhoid prevention pressure wedge. 884.5200... Devices § 884.5200 Hemorrhoid prevention pressure wedge. (a) Identification. A hemorrhoid prevention... hemorrhoids associated with vaginal childbirth. (b) Classification. Class II (special controls). The special...

21 CFR 884.5200 - Hemorrhoid prevention pressure wedge.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hemorrhoid prevention pressure wedge. 884.5200... Devices § 884.5200 Hemorrhoid prevention pressure wedge. (a) Identification. A hemorrhoid prevention... hemorrhoids associated with vaginal childbirth. (b) Classification. Class II (special controls). The special...

Erosion controls transpressional wedge kinematics

NASA Astrophysics Data System (ADS)

Leever, K. A.; Oncken, O.

2012-04-01

High resolution digital image analysis of analogue tectonic models reveals that erosion strongly influences the kinematics of brittle transpressional wedges. In the basally-driven experimental setup with low-angle transpression (convergence angle of 20 degrees) and a homogeneous brittle rheology, a doubly vergent wedge develops above the linear basal velocity discontinuity. In the erosive case, the experiment is interrupted and the wedge topography fully removed at displacement increments of ~3/4 the model thickness. The experiments are observed by a stereo pair of high resolution CCD cameras and the incremental displacement field calculated by Digital Particle Image Velocimetry (DPIV). From this dataset, fault slip on individual fault segments - magnitude and angle on the horizontal plane relative to the fault trace - is extracted using the method of Leever et al. (2011). In the non-erosive case, after an initial stage of strain localization, the wedge experiences two transient stages of (1) oblique slip and (2) localized strain partitioning. In the second stage, the fault slip angle on the pro-shear(s) rotates by some 30 degrees from oblique to near-orthogonal. Kinematic steady state is attained in the third stage when a through-going central strike-slip zone develops above the basal velocity discontinuity. In this stage, strain is localized on two main faults (or fault zones) and fully partitioned between plate boundary-parallel displacement on the central strike-slip zone and near-orthogonal reverse faulting at the front (pro-side) of the wedge. The fault slip angle on newly formed pro-shears in this stage is stable at 60-65 degrees (see also Leever et al., 2011). In contrast, in the erosive case, slip remains more oblique on the pro-shears throughout the experiment and a separate central strike-slip zone does not form, i.e. strain partitioning does not fully develop. In addition, more faults are active simultaneously. Definition of stages is based on slip on

Fracture and contact problems for an elastic wedge

NASA Technical Reports Server (NTRS)

Erdogan, F.; Arin, K.

1974-01-01

The plane elastostatic contact problem for an infinite elastic wedge of arbitrary angle is discussed. The medium is loaded through a frictionless rigid wedge of a given symmetric profile. Using the Mellin transform formulation the mixed boundary value problem is reduced to a singular integral equation with the contact stress as the unknown function. With the application of the results to the fracture of the medium in mind, the main emphasis in the study has been on the investigation of the singular nature of the stress state around the apex of the wedge and on the determination of the contact pressure.

Fracture and contact problems for an elastic wedge

NASA Technical Reports Server (NTRS)

Erdogan, F.; Arin, K.

1976-01-01

The paper deals with the plane elastostatic contact problem for an infinite elastic wedge of arbitrary angle. The medium is loaded through a frictionless rigid wedge of a given symmetric profile. Using the Mellin transform formulation the mixed boundary value problem is reduced to a singular integral equation with the contact stress as the unknown function. With the application of the results to the fracture of the medium in mind, the main emphasis in the study has been on the investigation of the singular nature of the stress state around the apex of the wedge and on the determination of the contact pressure.

Glass Microbeads in Analog Models of Thrust Wedges.

PubMed

D'Angelo, Taynara; Gomes, Caroline J S

2017-01-01

Glass microbeads are frequently used in analog physical modeling to simulate weak detachment zones but have been neglected in models of thrust wedges. Microbeads differ from quartz sand in grain shape and in low angle of internal friction. In this study, we compared the structural characteristics of microbeads and sand wedges. To obtain a better picture of their mechanical behavior, we determined the physical and frictional properties of microbeads using polarizing and scanning electron microscopy and ring-shear tests, respectively. We built shortening experiments with different basal frictions and measured the thickness, slope and length of the wedges and also the fault spacings. All the microbeads experiments revealed wedge geometries that were consistent with previous studies that have been performed with sand. However, the deformation features in the microbeads shortened over low to intermediate basal frictions were slightly different. Microbeads produced different fault geometries than sand as well as a different grain flow. In addition, they produced slip on minor faults, which was associated with distributed deformation and gave the microbeads wedges the appearance of disharmonic folds. We concluded that the glass microbeads may be used to simulate relatively competent rocks, like carbonates, which may be characterized by small-scale deformation features.

Aligning Optical Fibers by Means of Actuated MEMS Wedges

NASA Technical Reports Server (NTRS)

Morgan, Brian; Ghodssi, Reza

2007-01-01

Microelectromechanical systems (MEMS) of a proposed type would be designed and fabricated to effect lateral and vertical alignment of optical fibers with respect to optical, electro-optical, optoelectronic, and/or photonic devices on integrated circuit chips and similar monolithic device structures. A MEMS device of this type would consist of a pair of oppositely sloped alignment wedges attached to linear actuators that would translate the wedges in the plane of a substrate, causing an optical fiber in contact with the sloping wedge surfaces to undergo various displacements parallel and perpendicular to the plane. In making it possible to accurately align optical fibers individually during the packaging stages of fabrication of the affected devices, this MEMS device would also make it possible to relax tolerances in other stages of fabrication, thereby potentially reducing costs and increasing yields. In a typical system according to the proposal (see Figure 1), one or more pair(s) of alignment wedges would be positioned to create a V groove in which an optical fiber would rest. The fiber would be clamped at a suitable distance from the wedges to create a cantilever with a slight bend to push the free end of the fiber gently to the bottom of the V groove. The wedges would be translated in the substrate plane by amounts Dx1 and Dx2, respectively, which would be chosen to move the fiber parallel to the plane by a desired amount Dx and perpendicular to the plane by a desired amount Dy. The actuators used to translate the wedges could be variants of electrostatic or thermal actuators that are common in MEMS.

The crack and wedging problem for an orthotropic strip

NASA Technical Reports Server (NTRS)

Cinar, A.; Erdogan, F.

1982-01-01

The plane elasticity problem for an orthotropic strip containing a crack parallel to its boundaries is considered. The problem is formulated under general mixed mode loading conditions. The stress intensity factors depend on two dimensionless orthotropic constants only. For the crack problem the results are given for a single crack and two collinear cracks. The calculated results show that of the two orthotropic constants the influence of the stiffness ratio on the stress intensity factors is much more significant than that of the shear parameter. The problem of loading the strip by a rigid rectangular lengths continuous contact is maintained along the wedge strip interface; at a certain critical wedge length the separation starts at the midsection of the wedge, and the length of the separation zone increases rapidly with increasing wedge length.

Seasonal Ice Wedge Dynamics in Fosheim Peninsula, Ellesmere Island, Nunavut

NASA Astrophysics Data System (ADS)

Ward, M. K.; Pollard, W. H.

2017-12-01

Areas with ice-rice permafrost are vulnerable to thermokarst (lowering of the land surface from melting ground ice). The Fosheim Peninsula on Ellesmere Island, Nunavut is a high Arctic polar desert system with cold permafrost 500 m thick that is ice-rich in the upper 20 - 30 m. Our team has been monitoring changing permafrost conditions on the Fosheim since 1990. In this area ground ice consists mainly of ice-wedge ice and massive tabular ice bodies. With a mean annual temperature of - 19°C, the area is still sensitive to thermokarst as experienced in 2012; one of the warmest summers on record there was a three-fold increase in thermokarst, with the accelerated deepening of ice wedge troughs and the development of retrogressive thaw slumps. In this study, 7 ice wedges were monitored for 7 weeks in July and August, 2017. Ice wedges were chosen to represent different conditions including varying tough depths (0.36 m to 1.2 m), secondary wedge, varying plant cover (heavily covered to bare soil) and one wedge initially experienced ponding from snow melt that subsequently drained. Data collected included active layer depth measurements, soil moisture, ground temperatures at ice wedge through and polygon centres, dGPS and GPR surveys. Using Worldview 2 satellite imagery from 2008, 2012, 2016, these sites were compared to assess changes in polygons at a landscape scale. Ice wedges are ubiquitous to the arctic but may respond differently within different high Arctic environments. With the majority of studies being focused in the lower arctic, this study provides important field data from a high arctic site.

Influence of the substorm current wedge on the Dst index

NASA Astrophysics Data System (ADS)

Friedrich, Erena; Rostoker, Gordon; Connors, Martin G.; McPherron, R. L.

1999-03-01

One of the major questions confronting researchers studying the nature of the solar-terrestrial interaction centers around whether or not the substorm expansive phase has any causal effect on the growth of the storm time ring current. This question is often addressed by using the Dst index as a proxy for the storm time ring current and inspecting the main phase growth of Dst in the context of the substorm expansive phases which occur in the same time frame as the ring current growth. In the past it has been assumed that the magnetic effects of the substorm current wedge have little influence on the Dst index because the current wedge is an asymmetric current system, while Dst is supposed to reflect changes in the symmetric component of the ring current. In this paper we shall shown that the substorm current wedge can have a significant effect on the present Dst index, primarily as a consequence of the fact that only four stations are presently used to formulate the index. Calculations are made assuming the instantaneous magnitude of the wedge current is constant at 1 MA. Hourly values of Dst may be as much as 50° smaller than those presented here because of variation of the wedge current over the hour. We shall show how the effect of the current wedge depends on the UT of the expansive phase onset, the angular extent of the current wedge, and the locale of the closure current in the magnetosphere. The fact that the substorm current wedge is a conjugate phenomenon has an important influence on the magnitude of the expansive phase effect in the Dst index.

Nonlinear dynamics of ice-wedge networks and resulting sensitivity to severe cooling events.

PubMed

Plug, L J; Werner, B T

2002-06-27

Patterns of subsurface wedges of ice that form along cooling-induced tension fractures, expressed at the ground surface by ridges or troughs spaced 10 30 m apart, are ubiquitous in polar lowlands. Fossilized ice wedges, which are widespread at lower latitudes, have been used to infer the duration and mean temperature of cold periods within Proterozoic and Quaternary climates, and recent climate trends have been inferred from fracture frequency in active ice wedges. Here we present simulations from a numerical model for the evolution of ice-wedge networks over a range of climate scenarios, based on the interactions between thermal tensile stress, fracture and ice wedges. We find that short-lived periods of severe cooling permanently alter the spacing between ice wedges as well as their fracture frequency. This affects the rate at which the widths of ice wedges increase as well as the network's response to subsequent climate change. We conclude that wedge spacing and width in ice-wedge networks mainly reflect infrequent episodes of rapidly falling ground temperatures rather than mean conditions.

Vertebral Osteotomies in Ankylosing Spondylitis—Comparison of Outcomes Following Closing Wedge Osteotomy versus Opening Wedge Osteotomy: A Systematic Review

PubMed Central

Ravinsky, Robert A.; Ouellet, Jean-Albert; Brodt, Erika D.; Dettori, Joseph R.

2013-01-01

Study Design Systematic review. Study Rationale To seek out and assess the best quality evidence available comparing opening wedge osteotomy (OWO) and closing wedge osteotomy (CWO) in patients with ankylosing spondylitis to determine whether their results differ with regard to several different subjective and objective outcome measures. Objective The aim of this study is to determine whether there is a difference in subjective and objective outcomes when comparing CWO and OWO in patients with ankylosing spondylitis suffering from clinically significant thoracolumbar kyphosis with respect to quality-of-life assessments, complication risks, and the amount of correction of the spine achieved at follow-up. Methods A systematic review was undertaken of articles published up to July 2012. Electronic databases and reference lists of key articles were searched to identify studies comparing effectiveness and safety outcomes between adult patients with ankylosing spondylitis who received closing wedge versus opening wedge osteotomies. Studies that included pediatric patients, polysegmental osteotomies, or revision procedures were excluded. Two independent reviewers assessed the strength of evidence using the GRADE criteria and disagreements were resolved by consensus. Results From a total of 67 possible citations, 4 retrospective cohorts (class of evidence III) met our inclusion criteria and form the basis for this report. No differences in Oswestry Disability Index, visual analog scale for pain, Scoliosis Research Society (SRS)-24 score, SRS-22 score, and patient satisfaction were reported between the closing and opening wedge groups across two studies. Regarding radiological outcomes following closing versus opening osteotomies, mean change in sagittal vertical axis ranged from 8.9 to 10.8 cm and 8.0 to 10.9 cm, respectively, across three studies; mean change in lumbar lordosis ranged from 36 to 47 degrees and 19 to 41 degrees across four studies; and mean change

Double wedge prism based beam deflector for precise laser beam steering

NASA Astrophysics Data System (ADS)

Tyszka, Krzysztof; Dobosz, Marek; Bilaszewski, Tomasz

2018-02-01

Aiming to increase laser beam pointing stability required in interferometric measurements, we designed a laser beam deflector intended for active laser beam stabilization systems. The design is based on two wedge-prisms: the deflecting wedge driven by a tilting piezo-platform and the fixed wedge to compensate initial beam deflection. Our design allows linear beam steering, independently in the horizontal or vertical direction, with resolution of less than 1 μrad in a range of more than 100 μrad, and no initial deflection of the beam. Moreover, the ratio of the output beam deflection angle and the wedge tilt angle is less than 0.1; therefore, the noise influence is significantly reduced in comparison to standard mirror-based deflectors. The theoretical analyses support the designing process and can serve as a guide to wedge-prism selection. The experimental results are in agreement with theory and confirm the advantages of the presented double wedge system.

The crack and wedging problem for an orthotropic strip

NASA Technical Reports Server (NTRS)

Cinar, A.; Erdogan, F.

1983-01-01

The plane elasticity problem for an orthotropic strip containing a crack parallel to its boundaries is considered. The problem is formulated under general mixed mode loading conditions. The stress intensity factors depend on two dimensionless orthotropic constants only. For the crack problem the results are given for a single crack and two collinear cracks. The calculated results show that of the two orthotropic constants the influence of the stiffness ratio on the stress intensity factors is much more significant than that of the shear parameter. The problem of loading the strip by a rigid rectangular lengths continuous contact is maintained along the wedge strip interface; at a certain critical wedge length the separation starts at the midsection of the wedge, and the length of the separation zone increases rapidly with increasing wedge length. Previously announced in STAR as N82-26707

[Biphasic ceramic wedge and plate fixation with locked adjustable screws for open wedge tibial osteotomy].

PubMed

Lavallé, F; Pascal-Mousselard, H; Rouvillain, J L; Ribeyre, D; Delattre, O; Catonné, Y

2004-10-01

The aim of this radiological study was to evaluate the use of a biphasic ceramic wedge combined with plate fixation with locked adjustable screws for open wedge tibial osteotomy. Twenty-six consecutive patients (27 knees) underwent surgery between December 1999 and March 2002 to establish a normal lower-limb axis. The series included 6 women and 20 men, mean age 50 years (16 right knees and 11 left knees). Partial weight-bearing with crutches was allowed on day 1. A standard radiological assessment was performed on day 1, 90, and 360 (plain AP and lateral stance films of the knee). A pangonogram was performed before surgery and at day 360. Presence of a lateral metaphyseal space, development of peripheral cortical bridges, and osteointegration of the bone substitute-bone interface were evaluated used to assess bone healing. The medial tibial angle between the line tangent to the tibial plateau and the anatomic axis of the tibia (beta) was evaluated to assess preservation of postoperative correction. The HKA angle was determined. Three patients were lost to follow-up and 23 patients (24 knees) were retained for analysis. At last follow-up, presence of peripheral cortical bridges and complete filling of the lateral metaphyseal space demonstrated bone healing in all patients. Good quality osteointegration was achieved since 21 knees did not present an interface between the bone substitute and native bone (homogeneous transition zone). The beta angle was unchanged for 23 knees. A normal axis was observed in patients (16 knees) postoperatively. Use of a biphasic ceramic wedge in combination with plate fixation with locked adjustable screws is a reliable option for open wedge tibial osteotomy. The bone substitute fills the gap well. Tolerance and integration are optimal. Bone healing is achieved. Plate fixation with protected weight bearing appears to be a solid assembly, maintaining these corrections.

Efficient Mining and Detection of Sequential Intrusion Patterns for Network Intrusion Detection Systems

NASA Astrophysics Data System (ADS)

Shyu, Mei-Ling; Huang, Zifang; Luo, Hongli

In recent years, pervasive computing infrastructures have greatly improved the interaction between human and system. As we put more reliance on these computing infrastructures, we also face threats of network intrusion and/or any new forms of undesirable IT-based activities. Hence, network security has become an extremely important issue, which is closely connected with homeland security, business transactions, and people's daily life. Accurate and efficient intrusion detection technologies are required to safeguard the network systems and the critical information transmitted in the network systems. In this chapter, a novel network intrusion detection framework for mining and detecting sequential intrusion patterns is proposed. The proposed framework consists of a Collateral Representative Subspace Projection Modeling (C-RSPM) component for supervised classification, and an inter-transactional association rule mining method based on Layer Divided Modeling (LDM) for temporal pattern analysis. Experiments on the KDD99 data set and the traffic data set generated by a private LAN testbed show promising results with high detection rates, low processing time, and low false alarm rates in mining and detecting sequential intrusion detections.

Three-Dimensional Vertebral Wedging in Mild and Moderate Adolescent Idiopathic Scoliosis

PubMed Central

Scherrer, Sophie-Anne; Begon, Mickaël; Leardini, Alberto; Coillard, Christine; Rivard, Charles-Hilaire; Allard, Paul

2013-01-01

Background Vertebral wedging is associated with spinal deformity progression in adolescent idiopathic scoliosis. Reporting frontal and sagittal wedging separately could be misleading since these are projected values of a single three-dimensional deformation of the vertebral body. The objectives of this study were to determine if three-dimensional vertebral body wedging is present in mild scoliosis and if there are a preferential vertebral level, position and plane of deformation with increasing scoliotic severity. Methodology Twenty-seven adolescent idiopathic scoliotic girls with mild to moderate Cobb angles (10° to 50°) participated in this study. All subjects had at least one set of bi-planar radiographs taken with the EOS® X-ray imaging system prior to any treatment. Subjects were divided into two groups, separating the mild (under 20°) from the moderate (20° and over) spinal scoliotic deformities. Wedging was calculated in three different geometric planes with respect to the smallest edge of the vertebral body. Results Factorial analyses of variance revealed a main effect for the scoliosis severity but no main effect of vertebral Levels (apex and each of the three vertebrae above and below it) (F = 1.78, p = 0.101). Main effects of vertebral Positions (apex and above or below it) (F = 4.20, p = 0.015) and wedging Planes (F = 34.36, p<0.001) were also noted. Post-hoc analysis demonstrated a greater wedging in the inferior group of vertebrae (3.6°) than the superior group (2.9°, p = 0.019) and a significantly greater wedging (p≤0.03) along the sagittal plane (4.3°). Conclusions Vertebral wedging was present in mild scoliosis and increased as the scoliosis progressed. The greater wedging of the inferior group of vertebrae could be important in estimating the most distal vertebral segment to be restrained by bracing or to be fused in surgery. Largest vertebral body wedging values obtained in the sagittal plane support the claim

Wedge measures parallax separations...on large-scale 70-mm

Treesearch

Steven L. Wert; Richard J. Myhre

1967-01-01

A new parallax wedge (range: 1.5 to 2 inches) has been designed for use with large-scaled 70-mm. aerial photographs. The narrow separation of the wedge allows the user to measure small parallax separations that are characteristic of large-scale photographs.

Regional Landscape Response to Wedge-Top Basin Formation

NASA Astrophysics Data System (ADS)

Ruetenik, G.; Moucha, R.; Hoke, G. D.; Val, P.

2017-12-01

Wedge-top basins are the result of regionally variable uplift along thrust faults downstream of a mountain range and provide an ideal environment to study the regional stream and surface response to local variations in rock uplift. In this study, we simulate the formation and evolution of a wedge-top basin using a landscape evolution model. In line with a previous study, we find that during deformation in the fold-and-thrust belt adjacent to a wedge-top basin, both channel slope and erosion rates are reduced, and these changes propagate as a wave of low erosion into the uplands. For a uniform background uplift rate, this reduced rate of erosion results in a net surface uplift and a decreased slope within and upstream of the wedge-top basin. Following the eventual breach of the basin's bounding thrust belt, a wave of high erosion propagates through the basin and increases the channel slope. We expand upon previous studies by testing our model against a wide range of model parameters, although in general we find that the onset of increased erosion can be delayed by up to several million years. The amount of surface uplift is highly dependent on flexural isostasy and therefore it is heavily influenced by the elastic thickness and erodbility parameters. Observed paleoerosion rates in a paired wedge-top foreland sequence in the Argentine Precordillera reveal similar histories of paleo-erosion, and present day stream profiles show evidence that support model outcomes.

Wedge Waveguides and Resonators for Quantum Plasmonics

PubMed Central

2015-01-01

Plasmonic structures can provide deep-subwavelength electromagnetic fields that are useful for enhancing light–matter interactions. However, because these localized modes are also dissipative, structures that offer the best compromise between field confinement and loss have been sought. Metallic wedge waveguides were initially identified as an ideal candidate but have been largely abandoned because to date their experimental performance has been limited. We combine state-of-the-art metallic wedges with integrated reflectors and precisely placed colloidal quantum dots (down to the single-emitter level) and demonstrate quantum-plasmonic waveguides and resonators with performance approaching theoretical limits. By exploiting a nearly 10-fold improvement in wedge-plasmon propagation (19 μm at a vacuum wavelength, λvac, of 630 nm), efficient reflectors (93%), and effective coupling (estimated to be >70%) to highly emissive (∼90%) quantum dots, we obtain Ag plasmonic resonators at visible wavelengths with quality factors approaching 200 (3.3 nm line widths). As our structures offer modal volumes down to ∼0.004λvac3 in an exposed single-mode waveguide–resonator geometry, they provide advantages over both traditional photonic microcavities and localized-plasmonic resonators for enhancing light–matter interactions. Our results confirm the promise of wedges for creating plasmonic devices and for studying coherent quantum-plasmonic effects such as long-distance plasmon-mediated entanglement and strong plasmon–matter coupling. PMID:26284499

Are Pericentric Inversions Reorganizing Wedge Shell Genomes?

PubMed Central

García-Souto, Daniel; Pérez-García, Concepción

2017-01-01

Wedge shells belonging to the Donacidae family are the dominant bivalves in exposed beaches in almost all areas of the world. Typically, two or more sympatric species of wedge shells differentially occupy intertidal, sublittoral, and offshore coastal waters in any given locality. A molecular cytogenetic analysis of two sympatric and closely related wedge shell species, Donax trunculus and Donax vittatus, was performed. Results showed that the karyotypes of these two species were both strikingly different and closely alike; whilst metacentric and submetacentric chromosome pairs were the main components of the karyotype of D. trunculus, 10–11 of the 19 chromosome pairs were telocentric in D. vittatus, most likely as a result of different pericentric inversions. GC-rich heterochromatic bands were present in both species. Furthermore, they showed coincidental 45S ribosomal RNA (rRNA), 5S rRNA and H3 histone gene clusters at conserved chromosomal locations, although D. trunculus had an additional 45S rDNA cluster. Intraspecific pericentric inversions were also detected in both D. trunculus and D. vittatus. The close genetic similarity of these two species together with the high degree of conservation of the 45S rRNA, 5S rRNA and H3 histone gene clusters, and GC-rich heterochromatic bands indicate that pericentric inversions contribute to the karyotype divergence in wedge shells. PMID:29215567

Origin of salt giants in abyssal serpentinite systems

NASA Astrophysics Data System (ADS)

Scribano, Vittorio; Carbone, Serafina; Manuella, Fabio C.; Hovland, Martin; Rueslåtten, Håkon; Johnsen, Hans-K.

2017-10-01

Worldwide marine salt deposits ranging over the entire geological record are generally considered climate-related evaporites, derived from the precipitation of salts (mainly chlorides and sulfates) from saturated solutions driven by solar evaporation of seawater. This explanation may be realistic for a salt thickness ≤100 m, being therefore inadequate for thicker (>1 km) deposits. Moreover, sub-seafloor salt deposits in deep marine basins are difficult to reconcile with a surface evaporation model. Marine geology reports on abyssal serpentinite systems provide an alternative explanation for some salt deposits. Seawater-driven serpentinization consumes water and increases the salinity of the associated aqueous brines. Brines can be trapped in fractures and cavities in serpentinites and the surrounding `country' rocks. Successive thermal dehydration of buried serpentinites can mobilize and accumulate the brines, forming highly saline hydrothermal solutions. These can migrate upwards and erupt onto the seafloor as saline geysers, which may form salt-saturated water pools, as are currently observed in numerous deeps in the Red Sea and elsewhere. The drainage of deep-seated saline brines to seafloor may be a long-lasting, effective process, mainly occurring in areas characterized by strong tectonic stresses and/or igneous intrusions. Alternatively, brines could be slowly expelled from fractured serpentinites by buoyancy gradients and, hence, separated salts/brines could intrude vertically into surrounding rocks, forming salt diapirs. Serpentinization is an ubiquitous, exothermic, long-lasting process which can modify large volumes of oceanic lithosphere over geological times. Therefore, buried salt deposits in many areas of the world can be reasonably related to serpentinites.

Split-wedge antennas with sub-5 nm gaps for plasmonic nanofocusing

DOE PAGES

Chen, Xiaoshu; Lindquist, Nathan C.; Klemme, Daniel J.; ...

2016-11-22

Here, we present a novel plasmonic antenna structure, a split-wedge antenna, created by splitting an ultrasharp metallic wedge with a nanogap perpendicular to its apex. The nanogap can tightly confine gap plasmons and boost the local optical field intensity in and around these opposing metallic wedge tips. This three-dimensional split-wedge antenna integrates the key features of nanogaps and sharp tips, i.e., tight field confinement and three-dimensional nanofocusing, respectively, into a single platform. We fabricate split-wedge antennas with gaps that are as small as 1 nm in width at the wafer scale by combining silicon V-grooves with template stripping and atomicmore » layer lithography. Computer simulations show that the field enhancement and confinement are stronger at the tip–gap interface compared to what standalone tips or nanogaps produce, with electric field amplitude enhancement factors exceeding 50 when near-infrared light is focused on the tip–gap geometry. The resulting nanometric hotspot volume is on the order of λ 3/10 6. Experimentally, Raman enhancement factors exceeding 10 7 are observed from a 2 nm gap split-wedge antenna, demonstrating its potential for sensing and spectroscopy applications.« less

Split-Wedge Antennas with Sub-5 nm Gaps for Plasmonic Nanofocusing

PubMed Central

2016-01-01

We present a novel plasmonic antenna structure, a split-wedge antenna, created by splitting an ultrasharp metallic wedge with a nanogap perpendicular to its apex. The nanogap can tightly confine gap plasmons and boost the local optical field intensity in and around these opposing metallic wedge tips. This three-dimensional split-wedge antenna integrates the key features of nanogaps and sharp tips, i.e., tight field confinement and three-dimensional nanofocusing, respectively, into a single platform. We fabricate split-wedge antennas with gaps that are as small as 1 nm in width at the wafer scale by combining silicon V-grooves with template stripping and atomic layer lithography. Computer simulations show that the field enhancement and confinement are stronger at the tip–gap interface compared to what standalone tips or nanogaps produce, with electric field amplitude enhancement factors exceeding 50 when near-infrared light is focused on the tip–gap geometry. The resulting nanometric hotspot volume is on the order of λ3/106. Experimentally, Raman enhancement factors exceeding 107 are observed from a 2 nm gap split-wedge antenna, demonstrating its potential for sensing and spectroscopy applications. PMID:27960527

Intervertebral disc adaptation to wedging deformation.

PubMed

Stokes, Ian A F; Aronsson, David D; Clark, Katherine C; Roemhildt, Maria L

2006-01-01

Although scoliosis includes wedge deformities of both vertebrae and discs, little is known about the causes of the discal changes, and whether they result from mechanical influences on growth and/or remodelling. An external apparatus attached to transvertebral pins applied compression and 15 degrees of angulation to each of two adjacent young rat caudal intervertebral discs for 5 weeks (four animals), or for 10 weeks (four animals). Each week, micro-CT scanning documented the in vivo discal wedging. After euthanasia, tail segments (three vertebrae and the 2 angulated discs) were excised and their flexibility was measured over a range of lateral bending. The angle of maximum flexibility was recorded. Then discs were fixed in situ (with the external apparatus in place) and sectioned for polarized light microscopy. The disc-wedging deformity averaged 15 degrees initially, it averaged 20 degrees after 5 weeks, and then reduced to 10 degrees (in 10 week animals). The lateral bending flexibility showed a distinct maximum at an average of 1.1 degrees from the in vivo position in the 5-week animals, indicating structural remodeling of the discs almost to the deformed geometry. The 10-week animals had maximum flexibility at 1.4 degrees from the in vivo position (no significant difference between 5 and 10-week animals.) Collagen crimp angles [Cassidy et al., Conn Tiss Res 1989, 23:75-88] were not significantly different between convex and concave sides, again suggesting that remodeling had occurred. In a mechanically induced scoliosis deformity in skeletally immature rats, the intervertebral discs underwent remodeling within 5 weeks. This indicates that this animal model is suitable for studying adaptive wedging changes in human scoliosis.

Proximal opening wedge osteotomy with wedge-plate fixation compared with proximal chevron osteotomy for the treatment of hallux valgus: a prospective, randomized study.

PubMed

Glazebrook, Mark; Copithorne, Peter; Boyd, Gordon; Daniels, Timothy; Lalonde, Karl-André; Francis, Patricia; Hickey, Michael

2014-10-01

Hallux valgus with an increased intermetatarsal angle is usually treated with a proximal metatarsal osteotomy. The proximal chevron osteotomy is commonly used but is technically difficult. This study compares the proximal opening wedge osteotomy of the first metatarsal with the proximal chevron osteotomy for the treatment of hallux valgus with an increased intermetatarsal angle. This prospective, randomized multicenter (three-center) study was based on the clinical outcome scores of the Short Form-36, the American Orthopaedic Foot & Ankle Society forefoot questionnaire, and the visual analog scale for pain, activity, and patient satisfaction. Subjects were assessed prior to surgery and at three, six, and twelve months postoperatively. Surgeon preference was evaluated based on questionnaires and the operative times required for each procedure. No significant differences were found for any of the patients' clinical outcome measurements between the two procedures. The proximal opening wedge osteotomy was found to lengthen, and the proximal chevron osteotomy was found to shorten, the first metatarsal. The intermetatarsal angles improved (decreased) significantly, from 14.8° ± 3.2° to 9.1° ± 2.9 (mean and standard deviation) after a proximal opening wedge osteotomy and from 14.6° ± 3.9° to 11.3° ± 4.0° after a proximal chevron osteotomy (p < 0.05 for both). Operative time required for performing a proximal opening wedge osteotomy is similar to that required for performing a proximal chevron osteotomy (mean and standard deviation, 67.1 ± 16.5 minutes compared with 69.9 ± 18.6 minutes; p = 0.510). Opening wedge and proximal chevron osteotomies have comparable radiographic outcomes and comparable clinical outcomes for pain, satisfaction, and function. The proximal opening wedge osteotomy lengthens, and the proximal chevron osteotomy shortens, the first metatarsal. The proximal opening wedge osteotomy was subjectively less technically demanding and was

The use of sternal wedge osteotomy in pectus surgery: when is it necessary?

PubMed

Kara, Murat; Gundogdu, Ahmet Gokhan; Kadioglu, Salih Zeki; Cayirci, Ertug Can; Taskin, Necati

2016-09-01

The Ravitch procedure is a well-established surgical procedure for correction of chest wall deformities. Sternal wedge osteotomy is an important part of this procedure. We studied the incidence of wedge osteotomy with respect to the type of chest wall deformity in patients undergoing surgical correction with the use of a recently developed chest wall stabilization system. A total of 47 patients, 39 (83%) male and 8 (17%) female with a mean age of 14.9 ± 2.1 years, underwent the Ravitch procedure. Twenty-four (51.1%) had pectus carinatum, 19 (40.4%) had pectus excavatum, and 4 (8.5%) had pectus arcuatum. A conventional or oblique sternal wedge osteotomy was performed as indicated, followed by chest wall stabilization using the MedXpert system. Of the 47 patients, 27 (57.4%) had a sternal wedge osteotomy. All cases of pectus arcuatum and redo cases underwent sternal wedge osteotomy. Pectus excavatum cases tended to have a greater incidence of wedge osteotomy compared to pectus carinatum cases (68.4% vs. 41.7%, p = 0.052). Patients with more resected ribs had a greater rate of wedge osteotomy (63.4%) compared to those with fewer resected ribs (16.7%, p = 0.043). A sternal wedge osteotomy is more commonly performed in patients with pectus excavatum compared to those with pectus carinatum. All redo and pectus arcuatum cases need a wedge osteotomy for proper correction. Wedge osteotomy is very likely in more aggressive corrections with more rib resections. © The Author(s) 2016.

10 CFR 63.322 - Human intrusion scenario.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Human intrusion scenario. 63.322 Section 63.322 Energy... REPOSITORY AT YUCCA MOUNTAIN, NEVADA Postclosure Public Health and Environmental Standards Human Intrusion Standard § 63.322 Human intrusion scenario. For the purposes of the analysis of human intrusion, DOE must...

Seismic reflection images of the accretionary wedge of Costa Rica

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

Shipley, T.H.; Stoffa, P.L.; McIntosh, K.

The large-scale structure of modern accretionary wedges is known almost entirely from seismic reflection investigations using single or grids of two-dimensional profiles. The authors will report on the first three-dimensional seismic reflection data volume collected of a wedge. This data set covers a 9-km-wide {times} 22-km-long {times} 6-km-thick volume of the accretionary wedge just arcward of the Middle America Trench off Costa Rica. The three-dimensional processing has improved the imaging ability of the multichannel data, and the data volume allows mapping of structures from a few hundred meters to kilometers in size. These data illustrate the relationships between the basement,more » the wedge shape, and overlying slope sedimentary deposits. Reflections from within the wedge define the gross structural features and tectonic processes active along this particular convergent margin. So far, the analysis shows that the subdued basement relief (horst and graben structures seldom have relief of more than a few hundred meters off Costa Rica) does affect the larger scale through going structural features within the wedge. The distribution of mud volcanoes and amplitude anomalies associated with the large-scale wedge structures suggests that efficient fluid migration paths may extend from the top of the downgoing slab at the shelf edge out into the lower and middle slope region at a distance of 50-100 km. Offscraping of the uppermost (about 45 m) sediment occurs within 4 km of the trench, creating a small pile of sediments near the trench lower slope. Underplating of parts of the 400-m-thick subducted sedimentary section begins at a very shallow structural level, 4-10 km arcward of the trench. Volumetrically, the most important accretionary process is underplating.« less

Stress singularities at the vertex of a cylindrically anisotropic wedge

NASA Technical Reports Server (NTRS)

Delale, F.; Erdogan, F.; Boduroglu, H.

1980-01-01

The plane elasticity problem for a cylindrically anisotropic solid is formulated. The form of the solution for an infinite wedge shaped domain with various homogeneous boundary conditions is derived and the nature of the stress singularity at the vertex of the wedge is studied. The characteristic equations giving the stress singularity and the angular distribution of the stresses around the vertex of the wedge are obtained for three standard homogeneous boundary conditions. The numerical examples show that the singular behavior of the stresses around the vertex of an anisotropic wedge may be significantly different from that of the isotropic material. Some of the results which may be of practical importance are that for a half plane the stress state at r = 0 may be singular and for a crack the power of stress singularity may be greater or less than 1/2.

Investigation of two-dimensional wedge exhaust nozzles for advanced aircraft

NASA Technical Reports Server (NTRS)

Maiden, D. L.; Petit, J. E.

1975-01-01

Two-dimensional wedge nozzle performance characteristics were investigated in a series of wind-tunnel tests. An isolated single-engine/nozzle model was used to study the effects of internal expansion area ratio, aftbody cowl boattail angle, and wedge length. An integrated twin-engine/nozzle model, tested with and without empenage surfaces, included cruise, acceleration, thrust vectoring and thrust reversing nozzle operating modes. Results indicate that the thrust-minus-aftbody drag performance of the twin two-dimensional nozzle integration is significantly higher, for speeds greater than Mach 0.8, than the performance achieved with twin axisymmetric nozzle installations. Significant jet-induced lift was obtained on an aft-mounted lifting surface using a cambered wedge center body to vector thrust. The thrust reversing capabilities of reverser panels installed on the two-dimensional wedge center body were very effective for static or in-flight operation.

Degradation and stabilization of ice wedges: Implications for assessing risk of thermokarst in northern Alaska

NASA Astrophysics Data System (ADS)

Kanevskiy, Mikhail; Shur, Yuri; Jorgenson, Torre; Brown, Dana R. N.; Moskalenko, Nataliya; Brown, Jerry; Walker, Donald A.; Raynolds, Martha K.; Buchhorn, Marcel

2017-11-01

Widespread degradation of ice wedges has been observed during the last decades in numerous areas within the continuous permafrost zone of Eurasia and North America. To study ice-wedge degradation, we performed field investigations at Prudhoe Bay and Barrow in northern Alaska during 2011-2016. In each study area, a 250-m transect was established with plots representing different stages of ice-wedge degradation/stabilization. Field work included surveying ground- and water-surface elevations, thaw-depth measurements, permafrost coring, vegetation sampling, and ground-based LiDAR scanning. We described cryostratigraphy of frozen soils and stable isotope composition, analyzed environmental characteristics associated with ice-wedge degradation and stabilization, evaluated the vulnerability and resilience of ice wedges to climate change and disturbances, and developed new conceptual models of ice-wedge dynamics that identify the main factors affecting ice-wedge degradation and stabilization and the main stages of this quasi-cyclic process. We found significant differences in the patterns of ice-wedge degradation and stabilization between the two areas, and the patterns were more complex than those previously described because of the interactions of changing topography, water redistribution, and vegetation/soil responses that can interrupt or reinforce degradation. Degradation of ice wedges is usually triggered by an increase in the active-layer thickness during exceptionally warm and wet summers or as a result of flooding or disturbance. Vulnerability of ice wedges to thermokarst is controlled by the thickness of the intermediate layer of the upper permafrost, which overlies ice wedges and protects them from thawing. In the continuous permafrost zone, degradation of ice wedges rarely leads to their complete melting; and in most cases wedges eventually stabilize and can then resume growing, indicating a somewhat cyclic and reversible process. Stabilization of ice wedges

Immiscibility of Fluid Phases at Magmatic-hydrothermal Transition: Formation of Various PGE-sulfide Mineralization for Layered Basic Intrusions

NASA Astrophysics Data System (ADS)

Zhitova, L.; Borisenko, A.; Morgunov, K.; Zhukova, I.

2007-12-01

Fluid inclusions in quartz of the Merensky Reef (Bushveld Complex, South Africa) and the Chineisky Pluton (Transbaikal Region, Russia) were studied using cryometry, microthermometry, Raman-spectroscopy, LA ICP- MS, scanning electronic microscopy, gas-chromatography and isotopic methods. This allowed us to document some examples of fluid phase separation resulting in formation of different types of PGE-sulfide mineralization for layered basic intrusions. The results obtained show at least three generations of fluid separated from boiling residual alumosilicate intercumulus liquid of the Merensky Reef. The earliest fluid phase composed of homogenous high-dense methane and nitrogen gas mixture was identified in primary gas and co-existing anomalous fluid inclusions from symplectitic quartz. The next generation, heterophase fluid, composed of brines containing a free low-dense (mostly of carbon dioxide) gas phase, was observed in primary multiphase and coexisting gas-rich inclusions of miarolitic quartz crystals. The latest generation was also a heterophase fluid (low salinity water-salt solution and free low-dense methane gas phase) found in primary water-salt and syngenetic gas inclusions from peripheral zones of miarolitic quartz crystals. For the Chineisky Pluton reduced endocontact magmatogene fluids changed to oxidized low salinity hydrothermal fluids in exocontact zone. This resulted in formation of sulfide-PGE enrichment marginal zones of intrusion. The results obtained give us a possibility to suggest that: 1) Fluid phase separation is a typical feature of magmatogene fluids for layered basic intrusions. 2) Reduced fluids can extract and transport substantial PGE and sulfide concentrations. 3) Oxidation of reduced fluids is one of the most important geochemical barriers causing abundant PGE minerals and sulfides precipitation. This in turn results in both formation of PGE reefs or enriched contact zones of layered basic intrusions. This work was supported by

28. REPRESENTATIVE CENTER WEDGE. BALANCE WHEELS ON TRACK, WITH RACK ...

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

28. REPRESENTATIVE CENTER WEDGE. BALANCE WHEELS ON TRACK, WITH RACK TO OUTSIDE, SHOWN TO RIGHT OF THE WEDGE. PHOTO TAKEN AT SOUTH SWING SPAN. - George P. Coleman Memorial Bridge, Spanning York River at U.S. Route 17, Yorktown, York County, VA

Hydrogeology and Extent of Saltwater Intrusion in the Northern Part of the Town of Oyster Bay, Nassau County, New York: 1995–98

USGS Publications Warehouse

Stumm, Frederick; Lange, Andrew D.; Candela, Jennifer L.

2004-01-01

that exceeded the New York State Department of Health Drinking Water Maximum Contaminant Levels. High iron or nitrate concentrations were detected in water samples taken in 1997–98 from 39 observation wells. Previous high concentrations resulted in the shutdown of two production wells.Four distinct areas of saltwater intrusion in the Oyster Bay study area were delineated—three were in the upper glacial aquifer, and the fourth was in the Lloyd aquifer. Borehole-geophysical-logging data indicated that three of these saltwater "wedges" ranged from a few feet thick to more than 100 feet thick and had sharp freshwater-saltwater interfaces. Chloride concentrations in water from eight observation wells within these wedges in 1997 ranged from 125 to 13,750 milligrams per liter. One production well in Bayville has been shut down as of 1996 and others in the area may be affected by these saltwater wedges.

Acoustic field of a wedge-shaped section of a spherical cap transducer

NASA Astrophysics Data System (ADS)

Ketterling, Jeffrey A.

2003-12-01

The acoustic pressure field at an arbitrary point in space is derived for a wedge-shaped section of a spherical cap transducer using the spatial impulse response (SIR) method. For a spherical surface centered at the origin, a wedge shape is created by taking cuts in the X-Y and X-Z planes and removing the smallest surface component. Analytic expressions are derived for the SIR based on spatial location. The expressions utilize the SIR solutions for a spherical cap transducer [Arditi et al., Ultrason. Imaging 3, 37-61 (1981)] with additional terms added to account for the reduced surface area of the wedge. Results from the numerical model are compared to experimental measurements from a wedge transducer with an 8-cm outer diameter and 9-cm geometric focus. The experimental and theoretical -3-dB beamwidths agreed to within 10%+/-5%. The SIR model for a wedge-shaped transducer is easily extended to other spherically curved transducer geometries that consist of combinations of wedge sections and spherical caps.

Acoustic field of a wedge-shaped section of a spherical cap transducer.

PubMed

Ketterling, Jeffrey A

2003-12-01

The acoustic pressure field at an arbitrary point in space is derived for a wedge-shaped section of a spherical cap transducer using the spatial impulse response (SIR) method. For a spherical surface centered at the origin, a wedge shape is created by taking cuts in the X-Y and X-Z planes and removing the smallest surface component. Analytic expressions are derived for the SIR based on spatial location. The expressions utilize the SIR solutions for a spherical cap transducer [Arditi et al., Ultrason. Imaging 3, 37-61 (1981)] with additional terms added to account for the reduced surface area of the wedge. Results from the numerical model are compared to experimental measurements from a wedge transducer with an 8-cm outer diameter and 9-cm geometric focus. The experimental and theoretical -3-dB beamwidths agreed to within 10% +/- 5%. The SIR model for a wedge-shaped transducer is easily extended to other spherically curved transducer geometries that consist of combinations of wedge sections and spherical caps.

A regional-scale estimation of ice wedge ice volumes in the Canadian High Arctic

NASA Astrophysics Data System (ADS)

Templeton, M.; Pollard, W. H.; Grand'Maison, C. B.

2016-12-01

Ice wedges are both prominent and environmentally vulnerable features in continuous permafrost environments. As the world's Arctic regions begin to warm, concern over the potential effects of ice wedge melt out has become an immediate issue, receiving much attention in the permafrost literature. In this study we estimate the volume of ice wedge ice for large areas in the Canadian High Arctic through the use of high resolution satellite imagery and the improved capabilities of Geographic Information Systems (GIS). The methodology used for this study is similar to that of one performed in Siberia and Alaska by Ulrich et al, in 2014. Utilizing Ulrich's technique, this study detected ice wedge polygons from satellite imagery using ArcGIS. The average width and depth of these ice wedges were obtained from a combination of field data and long-term field studies for the same location. The assumptions used in the analysis of ice wedge volume have been tested, including trough width being representative of ice wedge width, and ice wedge ice content (Pollard and French 1980). This study used specific field sites located near Eureka on Ellesmere Island (N80°01', W85°43') and at Expedition Fiord on Axel Heiberg Island (N79°23', W90°59'). The preliminary results indicate that the methodology used by Ulrich et al, 2014 is transferrable to the Canadian High Arctic, and that ice wedge volumes range between 3-10% of the upper part of permafrost. These findings are similar to previous studies and their importance is made all the more evident by the dynamic nature of ice wedges where it could be argued that they are a key driver of thermokarst terrain. The ubiquitous nature of ice wedges across arctic terrain highlights the importance and the need to improve our understanding of ice wedge dynamics, as subsidence from ice wedge melt-out could lead to large scale landscape change.

[Analysis of intrusion errors in free recall].

PubMed

Diesfeldt, H F A

2017-06-01

Extra-list intrusion errors during five trials of the eight-word list-learning task of the Amsterdam Dementia Screening Test (ADST) were investigated in 823 consecutive psychogeriatric patients (87.1% suffering from major neurocognitive disorder). Almost half of the participants (45.9%) produced one or more intrusion errors on the verbal recall test. Correct responses were lower when subjects made intrusion errors, but learning slopes did not differ between subjects who committed intrusion errors and those who did not so. Bivariate regression analyses revealed that participants who committed intrusion errors were more deficient on measures of eight-word recognition memory, delayed visual recognition and tests of executive control (the Behavioral Dyscontrol Scale and the ADST-Graphical Sequences as measures of response inhibition). Using hierarchical multiple regression, only free recall and delayed visual recognition retained an independent effect in the association with intrusion errors, such that deficient scores on tests of episodic memory were sufficient to explain the occurrence of intrusion errors. Measures of inhibitory control did not add significantly to the explanation of intrusion errors in free recall, which makes insufficient strength of memory traces rather than a primary deficit in inhibition the preferred account for intrusion errors in free recall.

Effects of altering heel wedge properties on gait with the Intrepid Dynamic Exoskeletal Orthosis.

PubMed

Ikeda, Andrea J; Fergason, John R; Wilken, Jason M

2018-06-01

The Intrepid Dynamic Exoskeletal Orthosis is a custom-made dynamic response carbon fiber device. A heel wedge, which sits in the shoe, is an integral part of the orthosis-heel wedge-shoe system. Because the device restricts ankle movement, the system must compensate to simulate plantarflexion and allow smooth forward progression during gait. To determine the influence of wedge height and durometer on the walking gait of individuals using the Intrepid Dynamic Exoskeletal Orthosis. Repeated measures. Twelve individuals walked over level ground with their Intrepid Dynamic Exoskeletal Orthosis and six different heel wedges of soft or firm durometer and 1, 2, or 3 cm height. Center of pressure velocity, joint moments, and roll-over shape were calculated for each wedge. Height and durometer significantly affected time to peak center of pressure velocity, time to peak internal dorsiflexion and knee extension moments, time to ankle moment zero crossing, and roll-over shape center of curvature anterior-posterior position. Wedge height had a significant influence on peak center of pressure velocity, peak dorsiflexion moment, time to peak knee extension moment, and roll-over shape radius and vertical center of curvature. Changes in wedge height and durometer systematically affected foot loading. Participants preferred wedges which produced ankle moment zero crossing timing, peak internal knee extension moment timing, and roll-over shape center of curvature anterior-posterior position close to that of able-bodied individuals. Clinical relevance Adjusting the heel wedge is a simple, straightforward way to adjust the orthosis-heel wedge-shoe system. Changing wedge height and durometer significantly alters loading of the foot and has great potential to improve an individual's gait.

Localization of observables in the Rindler wedge

NASA Astrophysics Data System (ADS)

Asorey, M.; Balachandran, A. P.; Marmo, G.; de Queiroz, A. R.

2017-11-01

One of the striking features of QED is that charged particles create a coherent cloud of photons. The resultant coherent state vectors of photons generate a nontrivial representation of the localized algebra of observables that do not support a representation of the Lorentz group: Lorentz symmetry is spontaneously broken. We show in particular that Lorentz boost generators diverge in this representation, a result shown also by Balachandran et al. [Eur. Phys. J. C 75, 89 (2015), 10.1140/epjc/s10052-015-3305-0] (see also the work by Balachandran et al. [Mod. Phys. Lett. A 28, 1350028 (2013), 10.1142/S0217732313500284]. Localization of observables, for example in the Rindler wedge, uses Poincaré invariance in an essential way [Int. J. Geom. Methods Mod. Phys. 14, 1740008 (2017)., 10.1142/S0219887817400084]. Hence, in the presence of charged fields, the photon observables cannot be localized in the Rindler wedge. These observations may have a bearing on the black hole information loss paradox, as the physics in the exterior of the black hole has points of resemblance to that in the Rindler wedge.

Machine Learning in Intrusion Detection

DTIC Science & Technology

2005-07-01

machine learning tasks. Anomaly detection provides the core technology for a broad spectrum of security-centric applications. In this dissertation, we examine various aspects of anomaly based intrusion detection in computer security. First, we present a new approach to learn program behavior for intrusion detection. Text categorization techniques are adopted to convert each process to a vector and calculate the similarity between two program activities. Then the k-nearest neighbor classifier is employed to classify program behavior as normal or intrusive. We demonstrate

Intrusion detection: systems and models

NASA Technical Reports Server (NTRS)

Sherif, J. S.; Dearmond, T. G.

2002-01-01

This paper puts forward a review of state of the art and state of the applicability of intrusion detection systems, and models. The paper also presents a classfication of literature pertaining to intrusion detection.

Refined numerical solution of the transonic flow past a wedge

NASA Technical Reports Server (NTRS)

Liang, S.-M.; Fung, K.-Y.

1985-01-01

A numerical procedure combining the ideas of solving a modified difference equation and of adaptive mesh refinement is introduced. The numerical solution on a fixed grid is improved by using better approximations of the truncation error computed from local subdomain grid refinements. This technique is used to obtain refined solutions of steady, inviscid, transonic flow past a wedge. The effects of truncation error on the pressure distribution, wave drag, sonic line, and shock position are investigated. By comparing the pressure drag on the wedge and wave drag due to the shocks, a supersonic-to-supersonic shock originating from the wedge shoulder is confirmed.

Double-Sided Wedge Model For Retreating Subduction Zones: Applications to the Apenninic and Hellenic Subduction Zones (Invited)

NASA Astrophysics Data System (ADS)

Brandon, M. T.; Willett, S.; Rahl, J. M.; Cowan, D. S.

2009-12-01

We propose a new model for the evolution of accreting wedges at retreating subduction zones. Advance and retreat refer to the polarity of the velocity of the overriding plate with respect to subduction zone. Advance indicates a velocity toward the subduction zone (e.g., Andes) and retreat, away from the subduction zone (e.g. Apennines, Crete). The tectonic mode of a subduction zone, whether advancing or retreating, is a result of both the rollback of the subducting plate and the absolute motion of the overriding plate. The Hellenic and Apenninic wedges are both associated with retreating subduction zones. The Hellenic wedge has been active for about 100 Ma, whereas the Apenninic wedge has been active for about 30 Ma. Comparison of maximum metamorphic pressures for exhumed rocks in these wedges (25 and 30 km, respectively) with the maximum thickness of the wedges at present (30 and 35 km, respectively) indicates that each wedge has maintained a relatively steady size during its evolution. This conclusion is based on the constraint that both frictional and viscous wedges are subject to the constraint of a steady wedge taper, so that thickness and width are strongly correlated. Both wedges show clear evidence of steady accretion during their full evolution, with accretionary fluxes of about 60 and 200 km2 Ma-1. These wedges also both show steady drift of material from the front to the rear of the wedge, with horizontal shortening dominating in the front of the wedge, and horizontal extension within the back of the wedge. We propose that these wedges represent two back-to-back wedges, with a convergent wedge on the leading side (proside), and a divergent wedge on the trailing side (retroside). In this sense, the wedges are bound by two plates. The subducting plate is familiar. It creates a thrust-sense traction beneath the proside of the wedge. The second plate is an “educting” plate, which is creates a normal-sense traction beneath the retroside of the wedge. The

Single crystal metal wedges for surface acoustic wave propagation

DOEpatents

Fisher, E.S.

1980-05-09

An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

Single crystal metal wedges for surface acoustic wave propagation

DOEpatents

Fisher, Edward S.

1982-01-01

An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

An international perspective on Facebook intrusion.

PubMed

Błachnio, Agata; Przepiorka, Aneta; Benvenuti, Martina; Cannata, Davide; Ciobanu, Adela Magdalena; Senol-Durak, Emre; Durak, Mithat; Giannakos, Michail N; Mazzoni, Elvis; Pappas, Ilias O; Popa, Camelia; Seidman, Gwendolyn; Yu, Shu; Wu, Anise M S; Ben-Ezra, Menachem

2016-08-30

Facebook has become one of the most popular social networking websites in the world. The main aim of the study was to present an international comparison of Facebook intrusion and Internet penetration while examining possible gender differences. The study consisted of 2589 participants from eight countries: China, Greece, Israel, Italy, Poland, Romania, Turkey, USA. Facebook intrusion and Internet penetration were taken into consideration. In this study the relationship between Facebook intrusion and Internet penetration was demonstrated. Facebook intrusion was slightly negatively related to Internet penetration in each country. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Mechanics of fold-and-thrust belts and accretionary wedges Cohesive Coulomb theory

NASA Technical Reports Server (NTRS)

Dahlen, F. A.; Suppe, J.; Davis, D.

1984-01-01

A self-consistent theory for the mechanics of thin-skinned accretionary Coulomb wedges is developed and applied to the active fold-and-thrust belt of western Taiwan. The state of stress everywhere within a critical wedge is determined by solving the static equilibrium equations subject to the appropriate boundary conditions. The influence of wedge cohesion, which gives rise to a concave curvature of the critical topographic surface and affects the orientation of the principal stresses and Coulomb fracture within the wedge, is considered. The shape of the topographic surface and the angles at which thrust faults step up from the basal decollement in the Taiwanese belt is analyzed taking into account the extensive structural and fluid-pressure data available there. It is concluded that the gross geometry and structure of the Taiwan wedge are consistent with normal laboratory frictional and fracture strengths of sedimentary rocks.

Multiple magmatism in an evolving suprasubduction zone mantle wedge: The case of the composite mafic-ultramafic complex of Gaositai, North China Craton

NASA Astrophysics Data System (ADS)

Yang, Fan; Santosh, M.; Tsunogae, T.; Tang, Li; Teng, Xueming

2017-07-01

The suprasubduction zone mantle wedge of active convergent margins is impregnated by melts and fluids leading to the formation of a variety of magmatic and metasomatic rock suites. Here we investigate a composite mafic-ultramafic intrusion at Gaositai, in the northern margin of the North China Craton (NCC). The hornblende gabbro-serpentinite-dunite-pyroxenite-gabbro-diorite suite surrounded by hornblendites of this complex has long been considered to represent an "Alaskan-type" zoned pluton. We present petrologic, mineral chemical, geochemical and zircon U-Pb and Lu-Hf data from the various rock types from Gaositai including hornblende gabbro, serpentinite, dunite, pyroxenite, diorite and the basement hornblendite which reveal the case of multiple melt generation and melt-peridotite interaction. Our new mineral chemical data from the mafic-ultramafic suite exclude an "Alaskan-type" affinity, and the bulk geochemical features are consistent with subduction-related magmatism with enrichment of LILE (K, Rb, and Ba) and LREE (La and Ce), and depletion of HFSE (Nb, Ta, Zr, and Hf) and HREE. Zircon U-Pb geochronology reveals that the hornblendites surrounding the Gaositai complex are nearly 2 billion years older than the intrusive complex and yield early Paleoproterozoic emplacement ages (2433-2460 Ma), followed by late Paleoproterozoic metamorphism (1897 Ma). The serpentinites trace the history of a long-lived and replenished ancient sub-continental lithospheric mantle with the oldest zircon population dated as 2479 Ma and 1896 Ma, closely corresponding with the ages obtained from the basement rock, followed by Neoproterozoic and Phanerozoic zircon growth. The oldest member in the Gaositai composite intrusion is the dunite that yields emplacement age of 755 Ma, followed by pyroxenite formed through the interaction of slab melt and wedge mantle peridotite at 401 Ma. All the rock suites also carry multiple population of younger zircons ranging in age from Paleozoic to

Contemporary sand wedge development in seasonally frozen ground and paleoenvironmental implications

NASA Astrophysics Data System (ADS)

Wolfe, Stephen A.; Morse, Peter D.; Neudorf, Christina M.; Kokelj, Steven V.; Lian, Olav B.; O'Neill, H. Brendan

2018-05-01

Contemporary sand wedges and sand veins are active in seasonally frozen ground within the extensive discontinuous permafrost zone in Northwest Territories, Canada. The region has a subarctic continental climate with 291 mm a-1 precipitation, -4.1 °C mean annual air temperature, warm summers (July mean 17.0 °C), and cold winters (January mean -26.6 °C). Five years of continuous observations indicate that interannual variation of the ground thermal regime is dominantly controlled by winter air temperature and snow cover conditions. At sandy sites, thin snow cover and high thermal conductivity promote rapid freezing, high rates of ground cooling, and low near-surface ground temperatures (-15 to -25 °C), resulting in thermal contraction cracking to depths of 1.2 m. Cracking potentials are high in sandy soils when air temperatures are <-30 °C on successive days, mean freezing season air temperatures are ≤-17 °C, and snow cover is <0.15 m thick. In contrast, surface conditions in peatlands maintain permafrost, but thermal contraction cracking does not occur because thicker snow cover and the thermal properties of peat prolong freezeback and maintain higher winter ground temperatures. A combination of radiocarbon dating, optical dating, and stratigraphic observations were used to differentiate sand wedge types and formation histories. Thermal contraction cracks that develop in the sandy terrain are filled by surface (allochthonous) and/or host (autochthonous) material during the thaw season. Epigenetic sand wedges infilled with allochthonous sand develop within former beach sediments beneath an active eolian sand sheet. Narrower and deeper syngenetic wedges developed within aggrading eolian sand sheets, whereas wider and shallower antisyngenetic wedges developed in areas of active erosion. Thermal contraction cracking beneath vegetation-stabilized surfaces leads to crack infilling by autochthonous host and overlying organic material, with resultant downturning and

Minimum work analysis on the critical taper accretionary wedges- insights from analogue modeling

NASA Astrophysics Data System (ADS)

Santimano, Tasca; Rosenau, Matthias; Oncken, Onno

2014-05-01

The Critical taper theory (CTT) is a fundamental concept for the understanding of mountain building processes. Based on force balance it predicts the preferred steady state geometry of an accretionary wedge system and its tectonic regime (extensive, compressive, stable). However, it does not specify which structures are formed and reactivated to reach the preferred state. The latter can be predicted by the minimum work concept. Here we test both concepts and their interplay by analysing two simple sand wedge models which differ only in the thickness of the basal detachment (a layer of glass beads). While the steady state critical taper is controlled by internal and basal friction coefficients and therefore the same in all experiments, different processes can minimise work by 1. reducing gravitational work e.g. by lowering the amount of uplift or volume uplifted, or 2. reducing frictional work e.g. by lowering the load or due to low friction coefficient along thrusts. Since a thick detachment allows entrainment of low friction material and therefore lowering of the friction along active thrusts, we speculate that the style of wedge growth will differ between the two models. We observe that the wedge with a thin basal detachment localizes strain at the toe of the wedge periodically and reactivate older faults to reach the critical topography. On the contrary, in the wedge with the thicker detachment layer, friction along thrusts is lowered due to the entrainment of low friction material from the detachment zone, subsequently increasing the lifetime of a thrust. Long thrust episodes are always followed by a fault of shorter lifetime, with the aim of reaching the critical taper. From the two experiments, we analyze the time-series evolution of the wedge to infer the work done by the two styles of deformation and predict the trend over time to differ but the maximum work to be similar Our observations show that the critical taper theory determines the geometry of the

Wedge and spring assembly for securing coils in electromagnets and dynamoelectric machines

DOEpatents

Lindner, Melvin; Cottingham, James G.

1996-03-12

A wedge and spring assembly for use in electromagnets or dynamoelectric machines having a housing with an axis therethrough and a plurality of coils supported on salient poles that extend radially inward from the housing toward the housing axis to define a plurality of interpole spaces. The wedge and spring assembly includes a nonmagnetic retainer spring and a nonmagnetic wedge. The retainer spring is formed to fit into one of the interpole spaces, and has juxtaposed ends defining between them a slit extending in a direction generally parallel to the housing axis. The wedge for insertion into the slit provides an outwardly directed force on respective portions of the juxtaposed ends to expand the slit so that respective portions of the retainer spring engage areas of the coils adjacent thereto, thereby resiliently holding the coils against their respective salient poles. The retainer spring is generally triangular shaped to fit within the interpole space, and the wedge is generally T-shaped.

Wedge and spring assembly for securing coils in electromagnets and dynamoelectric machines

DOEpatents

Lindner, M.; Cottingham, J.G.

1996-03-12

A wedge and spring assembly for use in electromagnets or dynamoelectric machines is disclosed having a housing with an axis therethrough and a plurality of coils supported on salient poles that extend radially inward from the housing toward the housing axis to define a plurality of interpole spaces. The wedge and spring assembly includes a nonmagnetic retainer spring and a nonmagnetic wedge. The retainer spring is formed to fit into one of the interpole spaces, and has juxtaposed ends defining between them a slit extending in a direction generally parallel to the housing axis. The wedge for insertion into the slit provides an outwardly directed force on respective portions of the juxtaposed ends to expand the slit so that respective portions of the retainer spring engage areas of the coils adjacent thereto, thereby resiliently holding the coils against their respective salient poles. The retainer spring is generally triangular shaped to fit within the interpole space, and the wedge is generally T-shaped. 6 figs.

Interaction of disturbances with an oblique detonation wave attached to a wedge

NASA Technical Reports Server (NTRS)

Lasseigne, D. G.; Hussaini, M. Y.

1993-01-01

The linear response of an oblique overdriven detonation to impose free stream disturbances or to periodic movements of the wedge is examined. The free stream disturbances are assumed to be steady vorticity waves and the wedge motions are considered to be time periodic oscillations either about a fixed pivot point or along the plane of symmetry of the wedge aligned with the incoming stream. The detonation is considered to be a region of infinitesimal thickness in which a finite amount of heat is released. The response to the imposed disturbances is a function of the Mach number of the incoming flow, the wedge angle, and the exothermocity of the reaction within the detonation. It is shown that as the degree of overdrive increases, the amplitude of the response increases significantly; furthermore, a fundamental difference in the dependence of the response on the parameters of the problem is found between the response to a free stream disturbance and to a disturbance emanating from the wedge surface.

Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens

PubMed Central

Hansen, S. M.; Schmandt, B.; Levander, A.; Kiser, E.; Vidale, J. E.; Abers, G. A.; Creager, K. C.

2016-01-01

Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location of Mount St Helens raises questions regarding the extent of the cold mantle wedge and the source region of melts that are responsible for volcanism. Here using, high-resolution active-source seismic data, we show that Mount St Helens sits atop a sharp lateral boundary in Moho reflectivity. Weak-to-absent PmP reflections to the west are attributed to serpentinite in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St Helens (<∼700 °C). These results suggest that the melt source region lies east towards Mount Adams. PMID:27802263

Wedge gate valves selecting essentials in pipeline systems designing based on permissible operation parameters

NASA Astrophysics Data System (ADS)

Zakirnichnaya, M. M.; Kulsharipov, I. M.

2017-10-01

Wedge gate valves are widely used at the fuel and energy complex enterprises. The pipeline valves manufacturers indicate the safe operation resource according to the current regulatory and technical documentation. In this case, the resource value of the valve body strength calculation results is taken into consideration as the main structural part. However, it was determined that the wedge gate valves fail before the assigned resource due to the occurrence of conditions under which the wedge breaks in the hooks and, accordingly, the sealing integrity is not ensured. In this regard, it became necessary to assess the conditions under which the resource should be assigned not only to the valve body, but also to take into account the wedge durability. For this purpose, wedge resource calculations were made using the example of ZKL2 250-25 and ZKL2 300-25 valves using the ABAQUS software package FE-SAFE module under the technological parameters influence on the basis of their stressstrain state calculation results. Operating conditions, under which the wedge resource value is lower than the one set by the manufacturer, were determined. A technique for limiting the operating parameters for ensuring the wedge durability during the wedge gate valve assigned resource is proposed.

Geoelectric imaging for saline water intrusion in Geopark zone of Ciletuh Bay, Indonesia

NASA Astrophysics Data System (ADS)

Ardi, N. D.; Iryanti, M.; Asmoro, C. P.; Yusuf, A.; Sundana, A. N. A.; Safura, H. Y.; Fitri, M.; Anggraeni, M.; Kurniawan, R.; Afrianti, R.; Sumarni

2018-05-01

Saline water intrusion in estuary is an urgent ecological encounter across the world. The Ciletuh Bay, located in the southern Sukabumi district, is an area with high cultivated potential becoming one of the most important geology tourism zones in Indonesia. However, salt water intrusion along the creek is a natural spectacle that disturbs the economic growth of the whole region. This research was intended at plotting the subsurface level of saltwater interventions into aquifers at the northern part of Ciletuh creek, Indonesia. The study implemented geoelectric imaging methods. 37 imaging datum were acquired using Wenner array configuration. The saline water were identified across the study area. The result of two dimensional cross-sectional resistivity shows that there is an indication of sea content in our measured soil, i.e. the smallest resistivity value is 0.579 Ωm found at a depth of 12.4 m to 19.8 m at a track length of 35 m to 60 m is categorized in the clayey which shows low groundwater quality. However, when compared with the results of direct observation of groundwater from the wells of residents, the water obtained is brackish water. A water chemistry test is conducted to ascertain the initial results of this method so that a potential sea intrusion potential map can be interpreted more clearly. This can consequently help as an extrapolative model to define depth to saline water at any site within the saline water zone in the study area.

Tectono-sedimentary evolution of salt controlled minibasin in a fold-an-thrust belt setting Example from the Sivas Basin Turkey and physical model.

NASA Astrophysics Data System (ADS)

Kergaravat, Charlie; Ribes, Charlotte; Darnault, Romain; Callot, Jean-Paul; Ringenbach, Jean-Claude

2017-04-01

The aim of this study is to present the influence of regional shortening on the evolution of a minibasin province and the associated foldbelt geometry based on a natural example, the Sivas Basin, then compared to a physical experiment. The Sivas Basin in the Central Anatolian Plateau (Turkey) is a foreland fold-and-thrust belt, displaying in the central part a typical wall and basin province characterized by spectacularly exposed minibasins, separated by continuous steep-flanked walls and diapirs over a large area (45x25 km). The advance of the orogenic wedge is expressed within the second generation of minibasins by a shortening-induced squeezing of diapirs. Network of walls and diapirs evolve form polygonal to linear pattern probably induced by the squeezing of pre-existing evaporite walls and diapirs, separating linear primary minibasins. From base to top of secondary minibasins, halokinetic structures seem to evolve from small-scale objects along diapir flanks, showing hook and wedges halokinetic sequences, to large stratigraphic wedging, megaflap and salt sheets. Minibasins show progressively more linear shape at right angle to the regional shortening and present angular unconformities along salt structures related to the rejuvenation of pre-existing salt diapirs and walls probably encouraged by the shortening tectonic regime. The advance of the fold-and-thrust belts during the minibasins emplacement is mainly expressed during the late stage of minibasins development by a complex polygonal network of small- and intermediate-scale tectonic objects: (1) squeezed evaporite walls and diapirs, sometimes thrusted forming oblique or vertical welds, (2) allochthonous evaporite sheets, (3) thrusts and strike-slip faults recording translation and rotation of minibasins about vertical axis. Some minibasins are also tilted, with up to vertical position, associated with both the salt expulsion during minibasins sinking, recorded by large stratigraphic wedge, and the late

Constructing entanglement wedges for Lifshitz spacetimes with Lifshitz gravity

NASA Astrophysics Data System (ADS)

Cheyne, Jonathan; Mattingly, David

2018-03-01

Holographic relationships between entanglement entropy on the boundary of a spacetime and the area of minimal surfaces in the bulk provide an important entry in the bulk/boundary dictionary. While constructing the necessary causal and entanglement wedges is well understood in asymptotically AdS spacetimes, less is known about the equivalent constructions in spacetimes with different asymptotics. In particular, recent attempts to construct entanglement and causal wedges for asymptotically Lifshitz solutions in relativistic gravitational theories have proven problematic. We note a simple observation, that a Lifshitz bulk theory, specifically a covariant formulation of Hořava-Lifshitz gravity coupled to matter, has causal propagation defined by Lifshitz modes. We use these modes to construct causal and entanglement wedges and compute the geometric entanglement entropy, which in such a construction matches the field theory prescription.

Porous Titanium Wedges in Lateral Column Lengthening for Adult-Acquired Flatfoot Deformity.

PubMed

Moore, Spencer H; Carstensen, S Evan; Burrus, M Tyrrell; Cooper, Truitt; Park, Joseph S; Perumal, Venkat

2017-10-01

Lateral column lengthening (LCL) is a common procedure for reconstruction of stage II flexible adult-acquired flatfoot deformity (AAFD). The recent development of porous titanium wedges for this procedure provides an alternative to allograft and autograft. The purpose of this study was to report radiographic and clinical outcomes achieved with porous titanium wedges in LCL. A retrospective analysis of 34 feet in 30 patients with AAFD that received porous titanium wedges for LCL from January 2011 to October 2014. Deformity correction was assessed using both radiographic and clinical parameters. Radiographic correction was assessed using the lateral talo-first metatarsal angle, the talonavicular uncoverage percentage, and the first metatarsocuneiform height. The hindfoot valgus angle was measured. Patients were followed from a minimum of 6 months up to 4 years (mean 16.1 months). Postoperative radiographs demonstrated significant correction in all 3 radiographic criteria and the hindfoot valgus angle. We had no cases of nonunion, no wedge migration, and no wedges have been removed to date. The most common complication was calcaneocuboid joint pain (14.7%). Porous titanium wedges in LCL can achieve good radiographic and clinical correction of AAFD with a low rate of nonunion and other complications. Level IV: Case series.

Capillary surfaces in a wedge: Differing contact angles

NASA Technical Reports Server (NTRS)

Concus, Paul; Finn, Robert

1994-01-01

The possible zero-gravity equilibrium configurations of capillary surfaces u(x, y) in cylindrical containers whose sections are (wedge) domains with corners are investigated mathematically, for the case in which the contact angles on the two sides of the wedge may differ. In such a situation the behavior can depart in significant qualitative ways from that for which the contact angles on the two sides are the same. Conditions are described under which such qualitative changes must occur. Numerically computed surfaces are depicted to indicate the behavior.

Spatial distribution, temporal variability, and chemistry of the salt wedge in the lower Charles River, Massachusetts, June 1998 to July 1999

USGS Publications Warehouse

Breault, R.F.; Barlow, L.K.; Reisig, K.D.; Parker, G.W.

2000-01-01

Harbor. Discharge to the harbor is controlled by the 'new' Charles River Dam in Boston (fig. 1). The Basin was created by construction of the 'old' Charles River Dam in 1908 to solve Boston's sanitary problems. Prior to the building of the old Charles River Dam, the lower Charles River was a tidal estuary in which the water levels rose and fell twice daily with the tidal cycle. Low tide would expose untreated sewage that was discharged directly into the river. Exposed sewage created noxious odors and served as a breeding ground for mosquitoes that caused sporadic epidemics of malaria and yellow fever (Jobin, 1998). Damming of the river interrupted the normal tidal cycle and flooded the estuary by creating a freshwater pool (the Basin) that had a constant water elevation of about 0.8 meters (m) above mean sea level. Flooding of the estuary initially improved sanitary conditions and the Basin became a source of enjoyment for the local population and the focus of a large waterfront park in Boston and Cambridge (Jobin, 1998).Although the infiltration of saltwater from the harbor into the Basin was anticipated when the old Charles River Dam was built, neither the magnitude nor the consequences of the infiltration was considered. By 1975, the Metropolitan District Commission (MDC) determined that harbor water covered about 80 percent of the river bottom within the Basin and composed about 50 percent of its depth. The MDC also concluded that fish kills and odors in the spring of 1975 were likely the result of the sulfide-rich saltwater mixing with the overlying freshwater (Metropolitan District Commission, 1975).Saltwater from Boston Harbor that enters the Basin is known as the 'salt wedge' because of the shape it assumes as it moves upstream. Freshwater discharge from upstream pushes against the intruding harbor water until the density differences cause stratification to occur; the freshwater then overrides the denser harbor water (Fischer and others, 1979). The depth from

Intrusion Detection in Database Systems

NASA Astrophysics Data System (ADS)

Javidi, Mohammad M.; Sohrabi, Mina; Rafsanjani, Marjan Kuchaki

Data represent today a valuable asset for organizations and companies and must be protected. Ensuring the security and privacy of data assets is a crucial and very difficult problem in our modern networked world. Despite the necessity of protecting information stored in database systems (DBS), existing security models are insufficient to prevent misuse, especially insider abuse by legitimate users. One mechanism to safeguard the information in these databases is to use an intrusion detection system (IDS). The purpose of Intrusion detection in database systems is to detect transactions that access data without permission. In this paper several database Intrusion detection approaches are evaluated.

Saltwater intrusion monitoring in Florida

USGS Publications Warehouse

Prinos, Scott T.

2016-01-01

Florida's communities are largely dependent on freshwater from groundwater aquifers. Existing saltwater in the aquifers, or seawater that intrudes parts of the aquifers that were fresh, can make the water unusable without additional processing. The quality of Florida's saltwater intrusion monitoring networks varies. In Miami-Dade and Broward Counties, for example, there is a well-designed network with recently constructed short open-interval monitoring wells that bracket the saltwater interface in the Biscayne aquifer. Geochemical analyses of water samples from the network help scientists evaluate pathways of saltwater intrusion and movement of the saltwater interface. Geophysical measurements, collected in these counties, aid the mapping of the saltwater interface and the design of monitoring networks. In comparison, deficiencies in the Collier County monitoring network include the positioning of monitoring wells, reliance on wells with long open intervals that when sampled might provide questionable results, and the inability of existing analyses to differentiate between multiple pathways of saltwater intrusion. A state-wide saltwater intrusion monitoring network is being planned; the planned network could improve saltwater intrusion monitoring by adopting the applicable strategies of the networks of Miami-Dade and Broward Counties, and by addressing deficiencies such as those described for the Collier County network.

Late Holocene ice wedges near Fairbanks, Alaska, USA: Environmental setting and history of growth

USGS Publications Warehouse

Hamilton, T.D.; Ager, T.A.; Robinson, S.W.

1983-01-01

Test trenches excavated into muskeg near Fairbanks in 1969 exposed a polygonal network of active ice wedges. The wedges occur in peat that has accumulated since about 3500 yr BP and have grown episodically as the permafrost table fluctuated in response to fires, other local site conditions and perhaps regional climatic changes. Radiocarbon dates suggest one or two episodes of ice-wedge growth between about 3500 and 2000 yr BP as woody peat accumulated at the site. Subsequent wedge truncation evidently followed a fire that charred the peat. Younger peat exhibits facies changes between sedge-rich components that filled troughs over the ice wedges and woody bryophytic deposits that formed beyond the troughs. A final episode of wedge development took place within the past few hundred years. Pollen data from the site indicate that boreal forest was present throughout the past 6000 yr, but that it underwent a gradual transition from a predominantly deciduous to a spruce-dominated assemblage. This change may reflect either local site conditions or a more general climatic shift to cooler, moister summers in late Holocene time. The history of ice-wedge growth shows that wedges can form and grow to more than 1 m apparent width under mean annual temperatures that probably are close to those of the Fairbanks area today (-3.5°C) and under vegetation cover similar to that of the interior Alaskan boreal forest. The commonly held belief that ice wedges develop only below mean annual air temperatures of -6 to -8°C in the zone of continuous permafrost is invalid.

Vertebral body or intervertebral disc wedging: which contributes more to thoracolumbar kyphosis in ankylosing spondylitis patients?

PubMed Central

Liu, Hao; Qian, Bang-Ping; Qiu, Yong; Wang, Yan; Wang, Bin; Yu, Yang; Zhu, Ze-Zhang

2016-01-01

Abstract Both vertebral body wedging and disc wedging are found in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis. However, their relative contribution to thoracolumbar kyphosis is not fully understood. The objective of this study was to compare different contributions of vertebral and disc wedging to the thoracolumbar kyphosis in AS patients, and to analyze the relationship between the apical vertebral wedging angle and thoracolumbar kyphosis. From October 2009 to October 2013, a total of 59 consecutive AS patients with thoracolumbar kyphosis with a mean age of 38.1 years were recruited in this study. Based on global kyphosis (GK), 26 patients with GK < 70° were assigned to group A, and the other 33 patients with GK ≥ 70° were included in group B. Each GK was divided into disc wedge angles and vertebral wedge angles. The wedging angle of each disc and vertebra comprising the thoracolumbar kyphosis was measured, and the proportion of the wedging angle to the GK was calculated accordingly. Intergroup and intragroup comparisons were subsequently performed to investigate the different contributions of disc and vertebra to the GK. The correlation between the apical vertebral wedging angle and GK was calculated by Pearson correlation analysis. The duration of disease and sex were also recorded in this study. With respect to the mean disease duration, significant difference was observed between the two groups (P < 0.01). The wedging angle and wedging percentage of discs were significantly higher than those of vertebrae in group A (34.8° ± 2.5° vs 26.7° ± 2.7°, P < 0.01 and 56.6% vs 43.4%, P < 0.01), whereas disc wedging and disc wedging percentage were significantly lower than vertebrae in group B (37.6° ± 7.0° vs 50.1° ± 5.1°, P < 0.01 and 42.7% vs 57.3%, P < 0.01). The wedging of vertebrae was significantly higher in group B than in group A (50.1° ± 5.1° vs 26.7° ± 2.7°, P < 0

Layered intrusions of the Duluth Complex, Minnesota, USA

USGS Publications Warehouse

Miller, J.D.; Ripley, E.M.; ,

1996-01-01

The Duluth Complex and associated subvolcanic intrusions comprise a large (5000 km2) intrusive complex in northeastern Minnesota that was emplaced into comagmatic volcanics during the development of the 1.1 Ga Midcontinent rift in North America. In addition to anorthositic and felsic intrusions, the Duluth Complex is composed of many individual mafic layered intrusions of tholeiitic affinity. The cumulate stratigraphies and cryptic variations of six of the better exposed and better studied intrusions are described here to demonstrate the variability in their cumulus mineral paragenesis.

Rifting by continental rotation, mantle flow and hotspot volcanism in the salt-depositing South Atlantic

NASA Astrophysics Data System (ADS)

Szatmari, P.

2012-04-01

Rabinowitz & LaBrecque (1979) proposed that Africa and South America separated between 130 Ma and 107 Ma by 11.1° rigid plate rotation about an Euler pole in NE Brazil. According to those authors, the two continents remained contiguous in the north as the wedge-shaped South Atlantic opened up between them and deposited salt mostly over oceanic crust. Subsequent seismic profiling and drilling showed that salt, restricted to north of the volcanic proto-Walvis Ridge, deposited over rift sediments and stretched-thinned continental crust. Increasingly accurate restorations by Nürnberg & Müller (1991), Aslanian et al. (2009), Torsvik et al. (2009), and Moulin et al. (2010) differentiated in both continents several rigid plates separated by active deformation zones. Still, tectonic analysis of the rifted margins indicates that the main Early Cretaceous event was the clockwise rotation of South America about an Euler pole in its northeast. Both rifting and volcanism, including the Paraná-Etendeka large igneous province, where most flood basalts erupted at 134.6 ± 0.6 Ma (Thiede & Vasconcelos, 2010), were controlled by distance and orientation of rift segments relative to that pole in NE Brazil. Rifting was active from latest Jurassic to early Albian time (Magnavita et al., 2011) over inherited late Proterozoic fold-thrust belts. By Aptian time a long, dry wedge-shaped basin formed north of the volcanic barrier of the proto-Walvis Ridge, widening southward to 700 km and subsiding deep below sea level in the Santos Basin. The basin was filled with oil-rich lacustrine limestone and marine salt, each more than 2 km thick, deposited in often desiccating shallow water over the partially hyperextended continental crust of the São Paulo Plateau (Zalán et al., 2010; Magnavita et al., 2011; Szatmari, 2011). Further south marine sediments deposited over oceanic crust. Surface subsidence of the long, deep sediment-starved rift wedge was shaped, prior to the deposition of the

Pilot Study: Foam Wedge Chin Support Static Tolerance Testing

DTIC Science & Technology

2017-10-24

AFRL-SA-WP-SR-2017-0026 Pilot Study : Foam Wedge Chin Support Static Tolerance Testing Austin M. Fischer, BS1; William W...COVERED (From – To) April – October 2017 4. TITLE AND SUBTITLE Pilot Study : Foam Wedge Chin Support Static Tolerance Testing 5a. CONTRACT NUMBER...prototype to mitigate the increase in helmet weight and forward center of gravity. The purpose of this pilot study was to determine the feasibility and

Salt-water encroachment in southern Nassau and southeastern Queens Counties, Long Island, New York

USGS Publications Warehouse

Lusczynski, N.J.; Swarzenski, Wolfgang V.

1966-01-01

deposits. It extends from the seaward areas inland about 2 miles into Island Park. The deep wedge extends into southeastern Queens County and southern Nassau County principally in the deeper parts of the Magothy (?) Formation and in the underlying clay member of the Raritan Formation. The leading edge of the deep wedge is at the base of the Magothy (?) Formation. This edge is apparently at the shoreline east of Lido Beach and extends inland about 4 miles to Woodmere and about 7 miles to South Ozone Park. Zones of diffusion as much as 6 miles wide and about 500 feet thick were delineated in the frontal part of the salty-water wedges. These thick and broad zones of diffusion were probably formed during the past 1,000 or more years in heterogeneous unconsolidated deposits by long- and short-term changes in sea level and in fresh-water outflow to the sea and by dispersion caused by the movements of the water and its salt mass. Changes in sea level and fresh-water outflow together produced appreciable advances and recessions of the salt-water front. The chemical compositions of the diffused water in all wedges are modified to some extent by base exchange and other physical and chemical processes and also by diffusion. The intermediate wedge of salty water is moving landward at a rate of less than 20 feet a year in the vicinity of Island Park and, thus, has moved less than 1,000 feet since 1900. The leading edge of the deep wedge has advanced landward at about 300 feet a :ear in Woodmere in southwestern Nassau County and about 160 feet a year at South Ozone Park in southeastern Queens County, principally under the influence of local withdrawals near the toe of the wedge. Between Hewlett and Lido Beach, the deep wedge is moving inland at the rate of about 10 feet a year under the influence of regional withdrawals in inland areas. Regional encroachment of the deep wedge is apparently retarded appreciably by cyclic flow, that is, by the return seaward in the upper

From intrusive to oscillating thoughts.

PubMed

Peirce, Anne Griswold

2007-10-01

This paper focused on the possibility that intrusive thoughts (ITs) are a form of an evolutionary, adaptive, and complex strategy to prepare for and resolve stressful life events through schema formation. Intrusive thoughts have been studied in relation to individual conditions, such as traumatic stress disorder and obsessive-compulsive disorder. They have also been documented in the average person experiencing everyday stress. In many descriptions of thought intrusion, it is accompanied by thought suppression. Several theories have been put forth to describe ITs, although none provides a satisfactory explanation as to whether ITs are a normal process, a normal process gone astray, or a sign of pathology. There is also no consistent view of the role that thought suppression plays in the process. I propose that thought intrusion and thought suppression may be better understood by examining them together as a complex and adaptive mechanism capable of escalating in times of need. The ability of a biological mechanism to scale up in times of need is one hallmark of a complex and adaptive system. Other hallmarks of complexity, including self-similarity across scales, sensitivity to initial conditions, presence of feedback loops, and system oscillation, are also discussed in this article. Finally, I propose that thought intrusion and thought suppression are better described together as an oscillatory cycle.

Vapor Intrusion

EPA Pesticide Factsheets

Vapor intrusion occurs when there is a migration of volatile chemicals from contaminated groundwater or soil into an overlying building. Volatile chemicals can emit vapors that may migrate through subsurface soils and into indoor air spaces.

Contact and crack problems for an elastic wedge. [stress concentration in elastic half spaces

NASA Technical Reports Server (NTRS)

Erdogan, F.; Gupta, G. D.

1974-01-01

The contact and the crack problems for an elastic wedge of arbitrary angle are considered. The problem is reduced to a singular integral equation which, in the general case, may have a generalized Cauchy kernel. The singularities under the stamp as well as at the wedge apex were studied, and the relevant stress intensity factors are defined. The problem was solved for various wedge geometries and loading conditions. The results may be applicable to certain foundation problems and to crack problems in symmetrically loaded wedges in which cracks initiate from the apex.

Wedge assembly for electrical transformer component spacing

DOEpatents

Baggett, Franklin E.; Cage, W. Franklin

1991-01-01

A wedge assembly that is easily inserted between two surfaces to be supported thereby, and thereafter expanded to produce a selected spacing between those surfaces. This wedge assembly has two outer members that are substantially identical except that they are mirror images of each other. Oppositely directed faces of these of these outer members are substantially parallel for the purpose of contacting the surfaces to be separated. The outer faces of these outer members that are directed toward each other are tapered so as to contact a center member having complementary tapers on both faces. A washer member is provided to contact a common end of the outer members, and a bolt member penetrates this washer and is threadably received in a receptor of the center member. As the bolt member is threaded into the center member, the center member is drawn further into the gap between the outer members and thereby separates these outer members to contact the surfaces to be separated. In the preferred embodiment, the contacting surfaces of the outer member and the center member are provided with guide elements. The wedge assembly is described for use in separating the secondary windings from the laminations of an electrical power transformer.

The Ronda peridotite (Spain): A natural template for seismic anisotropy in subduction wedges

NASA Astrophysics Data System (ADS)

Précigout, Jacques; Almqvist, Bjarne S. G.

2014-12-01

The origin of seismic anisotropy in mantle wedges remains elusive. Here we provide documentation of shear wave anisotropy (AVs) inferred from mineral fabric across a lithosphere-scale vestige of deformed mantle wedge in the Ronda peridotite. As predicted for most subduction wedges, this natural case exposes a transition from A-type to B-type olivine fabric that occurs with decreasing temperature and enhanced grain boundary sliding at the expense of dislocation creep. We show that B-type fabric AVs (maximum of 6%) does not support geophysical observations and modeling, which requires 8% AVs. However, an observed transitional olivine fabric (A/B) develops at intermediate temperatures (800-1000°C) and can generate AVs ≥ 8%. We predict that the A/B-type fabric can account for shear wave splitting in contrasting subduction settings, exemplified by the Ryukyu and Honshu subduction wedges. The Ronda peridotite therefore serves as a natural template to decipher the mantle wedge deformation from seismic anisotropy.

Slamming pressures on the bottom of a free-falling vertical wedge

NASA Astrophysics Data System (ADS)

Ikeda, C. M.; Judge, C. Q.

2013-11-01

High-speed planing boats are subjected to repeat impacts due to slamming, which can cause structural damage and injury to passengers. A first step in understanding and predicting the physics of a craft re-entering the water after becoming partially airborne is an experimental vertical drop test of a prismastic wedge (deadrise angle, β =20° beam, B = 300 mm; and length, L = 600 mm). The acrylic wedge was mounted to a rig allowing it to free-fall into a deep-water tank (5.2m × 5.2m × 4.2m deep) from heights 0 <= H <= 635 mm, measured from the keel to the free surface. The wedge was instrumented to record vertical position, acceleration, and pressure on the bottom surface. A pressure mapping system, capable of measuring several points over the area of the thin (0.1 mm) film sensor at sampling rates up to 20 kHz, is used and compared to surface-mounted pressure transducers (sampled at 10 kHz). A high speed camera (1000 fps, resolution of 1920 × 1200 pixels) is mounted above the wedge model to record the wetted surface as the wedge descended below the free surface. The pressure measurements taken with both conventional surface pressure transducers and the pressure mapping system agree within 10% of the peak pressure values (0.7 bar, typical). Supported by the Office of Naval Research.

Identifying seawater intrusion in coastal areas by means of 1D and quasi-2D joint inversion of TDEM and VES data

NASA Astrophysics Data System (ADS)

Martínez-Moreno, F. J.; Monteiro-Santos, F. A.; Bernardo, I.; Farzamian, M.; Nascimento, C.; Fernandes, J.; Casal, B.; Ribeiro, J. A.

2017-09-01

Seawater intrusion is an increasingly widespread problem in coastal aquifers caused by climate changes -sea-level rise, extreme phenomena like flooding and droughts- and groundwater depletion near to the coastline. To evaluate and mitigate the environmental risks of this phenomenon it is necessary to characterize the coastal aquifer and the salt intrusion. Geophysical methods are the most appropriate tool to address these researches. Among all geophysical techniques, electrical methods are able to detect seawater intrusions due to the high resistivity contrast between saltwater, freshwater and geological layers. The combination of two or more geophysical methods is recommended and they are more efficient when both data are inverted jointly because the final model encompasses the physical properties measured for each methods. In this investigation, joint inversion of vertical electric and time domain soundings has been performed to examine seawater intrusion in an area within the Ferragudo-Albufeira aquifer system (Algarve, South of Portugal). For this purpose two profiles combining electrical resistivity tomography (ERT) and time domain electromagnetic (TDEM) methods were measured and the results were compared with the information obtained from exploration drilling. Three different inversions have been carried out: single inversion of the ERT and TDEM data, 1D joint inversion and quasi-2D joint inversion. Single inversion results identify seawater intrusion, although the sedimentary layers detected in exploration drilling were not well differentiated. The models obtained with 1D joint inversion improve the previous inversion due to better detection of sedimentary layer and the seawater intrusion appear to be better defined. Finally, the quasi-2D joint inversion reveals a more realistic shape of the seawater intrusion and it is able to distinguish more sedimentary layers recognised in the exploration drilling. This study demonstrates that the quasi-2D joint

Effect of sodium monofluorophosphate treatment on microstructure and frost salt scaling durability of slag cement paste

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

Copuroglu, O.; Fraaij, A.L.A.; Bijen, J.M.J.M.

2006-08-15

Sodium-monofluorophosphate (Na-MFP) is currently in use as a surface applied corrosion inhibitor in the concrete industry. Its basic mechanism is to protect the passive layer of the reinforcement steel against disruption due to carbonation. Carbonation is known as the most detrimental environmental effect on blast furnace slag cement (BFSC) concrete with respect to frost salt scaling. In this paper the effect of Na-MFP on the microstructure and frost salt scaling resistance of carbonated BFSC paste is presented. The results of electron microscopy, mercury intrusion porosimetry (MIP) and X-ray diffraction (XRD) are discussed. It is found that the treatment modifies themore » microstructure and improves the resistance of carbonated BFSC paste against frost salt attack.« less

A system for distributed intrusion detection

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

Snapp, S.R.; Brentano, J.; Dias, G.V.

1991-01-01

The study of providing security in computer networks is a rapidly growing area of interest because the network is the medium over which most attacks or intrusions on computer systems are launched. One approach to solving this problem is the intrusion-detection concept, whose basic premise is that not only abandoning the existing and huge infrastructure of possibly-insecure computer and network systems is impossible, but also replacing them by totally-secure systems may not be feasible or cost effective. Previous work on intrusion-detection systems were performed on stand-alone hosts and on a broadcast local area network (LAN) environment. The focus of ourmore » present research is to extend our network intrusion-detection concept from the LAN environment to arbitarily wider areas with the network topology being arbitrary as well. The generalized distributed environment is heterogeneous, i.e., the network nodes can be hosts or servers from different vendors, or some of them could be LAN managers, like our previous work, a network security monitor (NSM), as well. The proposed architecture for this distributed intrusion-detection system consists of the following components: a host manager in each host; a LAN manager for monitoring each LAN in the system; and a central manager which is placed at a single secure location and which receives reports from various host and LAN managers to process these reports, correlate them, and detect intrusions. 11 refs., 2 figs.« less

[Spectral Study on the Effects of Angle-Tuned Filter Wedge Angle Parameter to Reflecting Characteristics].

PubMed

Yu, Kan; Huang, De-xiu; Yin, Juan-juan; Bao, Jia-qi

2015-08-01

Three-port tunable optical filter is a key device in the all-optic intelligent switching network and dense wavelength division multiplexing system. The characteristics of the reflecting spectrum, especially the reflectivity and the isolation degree are very important to the three-port filter. Angle-tuned thin film filter is widely used as a three-port tunable filter for its high rectangular degree and good temperature stability. The characteristics of the reflecting spectrum are greatly influenced not only by the incident angle, but also by the wedge angle parameter of the non-paralleled wedge thin film filter. In the present paper, the influences of the wedge angle parameter to the reflectivity and the half bandwidth are analyzed, and the reflecting spectrum characterstics are simulationed in different wedge angle parameter and polarity. The wedge angle-tuned thin film filter with 0.8° wedge angle parameter is fabricated. The experimental results show that keeping the wedge angle the same orientation to the incident angle will worsen the reflectivity and the rectangular degree of the reflecting spectrum. However, keeping the wedge angle orientation reverse to the incident angle will enhance the reflectivity and decrease the bandwidth, which will give higher reflectivity and isolation degree to the three-port filter than that of high parallel degree angle-tuned thin film filter.

Starting of generic inlet with blunted wedges

NASA Astrophysics Data System (ADS)

Borovoy, V.; Mosharov, V.; Radchenko, V.; Skuratov, A.; Struminskaya, I.

2017-06-01

Bluntness e¨ect of gas-compressing wedges on starting and §ow structure in an air inlet was investigated experimentally. The inlet was of internal compression type with §at walls and rectangular cross section. The experiments were carried out in the wind tunnel UT-1M at Mach numbers M = 5 and 8 and Reynolds numbers Re∞L from 2.8 · 106 to 23 · 106. The §ow characteristics were measured by panoramic optical methods. Data demonstrating in§uence of wedge bluntness radius on the inlet starting were obtained at di¨erent Mach and Reynolds numbers as well as at di¨erent contraction ratios. Ambiguity of the §ow regime in the inlet under certain conditions was found.

Experimental study on the Neapolitan Yellow Tuff: Salt weathering and consolidation

NASA Astrophysics Data System (ADS)

La Russa, Mauro Francesco; Ruffolo, Silvestro Antonio; Alvarez de Buergo, Monica; Ricca, Michela; Belfiore, Cristina Maria; Pezzino, Antonino; Mirocle Crisci, Gino

2016-04-01

Salt crystallization is one of the major weathering agents in porous building materials due to the crystallization pressure exerted by salt crystals growing in confined pores. The consolidation of such degraded stone materials is a crucial issue in the field of Cultural Heritage restoration. This contribution deals with laboratory experimentation carried out on the Neapolitan Tuff, a pyroclastic rock largely used in the Campanian architecture. Several specimens, collected from a historical quarry nearby the city of Naples, were treated with two different consolidating products: a suspension of nanosilica in water (Syton X30®) and ethyl silicate (Estel 1000®) dispersed in organic solvent (TEOS). Then, in order to assess the effectiveness of consolidation treatments, both treated and untreated samples underwent accelerated degradation through salt crystallization tests. A multi-analytical approach, including mercury intrusion porosimetry, peeling tests and point load test, was employed to evaluate the correlation between the salt crystallization and the micro-structural features of the examined tuff specimens. In addition, the calculation of the crystallization pressures was also performed in order to make a correlation between the porous structure of the tuff and its susceptivity to salt crystallization. Obtained results show that both the tested products increase the resistance of tuff to salt crystallization, although inducing an increase of crystallization pressure. Ethyl silicate, however, shows a better behaviour in terms of superficial cohesion, even after several degradation cycles.

Water Intrusion Problems in Transit Tunnels

DOT National Transportation Integrated Search

1986-05-01

This report presents the findings of five case studies in which an in-depth analysis was made of tunnel water intrusion problems in transit tunnels. Water intrusion parameters of transit systems in Atlanta, Boston, Buffalo, New York and Washington, D...

Wedge geometry, frictional properties and interseismic coupling of the Java megathrust

NASA Astrophysics Data System (ADS)

Koulali, Achraf; McClusky, Simon; Cummins, Phil; Tregoning, Paul

2018-06-01

The mechanical interaction between rocks at fault zones is a key element for understanding how earthquakes nucleate and propagate. Therefore, estimating frictional properties along fault planes allows us to infer the degree of elastic strain accumulation throughout the seismic cycle. The Java subduction zone is an active plate boundary where high seismic activity has long been documented. However, very little is known about the seismogenic processes of the megathrust, especially its shallowest portion where onshore geodetic networks are insensitive to recover the pattern of elastic strain. Here, we use the geometry of the offshore accretionary prism to infer frictional properties along the Java subduction zone, using Coulomb critical taper theory. We show that large portions of the inner wedge in the eastern part of the Java subduction megathrust are in a critical state, where the wedge is on the verge of failure everywhere. We identify four clusters with an internal coefficient of friction μint of ∼ 0.8 and hydrostatic pore pressure within the wedge. The average effective coefficient of friction ranges between 0.3 and 0.4, reflecting a strong décollement. Our results also show that the aftershock sequence of the 1994 Mw 7.9 earthquake halted adjacent to a critical segment of the wedge, suggesting that critical taper wedge areas in the eastern Java subduction interface may behave as a permanent barrier to large earthquake rupture. In contrast, in western Java topographic slope and slab dip profiles suggest that the wedge is mechanically stable, i.e deformation is restricted to sliding along the décollement, and likely to coincide with a seismogenic portion of the megathrust. We discuss the seismic hazard implications and highlight the importance of considering the segmentation of the Java subduction zone when assessing the seismic hazard of this region.

Analysis and measurement of electromagnetic scattering by pyramidal and wedge absorbers

NASA Technical Reports Server (NTRS)

Dewitt, B. T.; Burnside, Walter D.

1986-01-01

By modifying the reflection coefficients in the Uniform Geometrical Theory of Diffraction a solution that approximates the scattering from a dielectric wedge is found. This solution agrees closely with the exact solution of Rawlins which is only valid for a few minor cases. This modification is then applied to the corner diffraction coefficient and combined with an equivalent current and geometrical optics solutions to model scattering from pyramid and wedge absorbers. Measured results from 12 inch pyramid absorbers from 2 to 18 GHz are compared to calculations assuming the returns add incoherently and assuming the returns add coherently. The measured results tend to be between the two curves. Measured results from the 8 inch wedge absorber are also compared to calculations with the return being dominated by the wedge diffraction. The procedures for measuring and specifying absorber performance are discussed and calibration equations are derived to calculate a reflection coefficient or a reflectivity using a reference sphere. Shaping changes to the present absorber designs are introduced to improve performance based on both high and low frequency analysis. Some prototypes were built and tested.

Achieving hard X-ray nanofocusing using a wedged multilayer Laue lens

DOE PAGES

Huang, Xiaojing; Conley, Raymond; Bouet, Nathalie; ...

2015-05-04

We report on the fabrication and the characterization of a wedged multilayer Laue lens for x-ray nanofocusing. The lens was fabricated using a sputtering deposition technique, in which a specially designed mask was employed to introduce a thickness gradient in the lateral direction of the multilayer. X-ray characterization shows an efficiency of 27% and a focus size of 26 nm at 14.6 keV, in a good agreement with theoretical calculations. These results indicate that the desired wedging is achieved in the fabricated structure. We anticipate that continuous development on wedged MLLs will advance x-ray nanofocusing optics to new frontiers andmore » enrich capabilities and opportunities for hard X-ray microscopy.« less

Achieving hard X-ray nanofocusing using a wedged multilayer Laue lens

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

Huang, Xiaojing; Conley, Raymond; Bouet, Nathalie

We report on the fabrication and the characterization of a wedged multilayer Laue lens for x-ray nanofocusing. The lens was fabricated using a sputtering deposition technique, in which a specially designed mask was employed to introduce a thickness gradient in the lateral direction of the multilayer. X-ray characterization shows an efficiency of 27% and a focus size of 26 nm at 14.6 keV, in a good agreement with theoretical calculations. These results indicate that the desired wedging is achieved in the fabricated structure. We anticipate that continuous development on wedged MLLs will advance x-ray nanofocusing optics to new frontiers andmore » enrich capabilities and opportunities for hard X-ray microscopy.« less

Dual Double-Wedge Pseudo-Depolarizer with Anamorphic PSF

NASA Technical Reports Server (NTRS)

Hill, Peter; Thompson, Patrick

2012-01-01

A polarized scene, which may occur at oblique illumination angles, creates a radiometric signal that varies as a function of viewing angle. One common optical component that is used to minimize such an effect is a polarization scrambler or depolarizer. As part of the CLARREO mission, the SOLARIS instrument project at Goddard Space Flight Center has developed a new class of polarization scramblers using a dual double-wedge pseudo-depolarizer that produces an anamorphic point spread function (PSF). The SOLARIS instrument uses two Wollaston type scramblers in series, each with a distinct wedge angle, to image a pseudo-depolarized scene that is free of eigenstates. Since each wedge is distinct, the scrambler is able to produce an anamorphic PSF that maintains high spatial resolution in one dimension by sacrificing the spatial resolution in the other dimension. This scrambler geometry is ideal for 1-D imagers, such as pushbroom slit spectrometers, which require high spectral resolution, high spatial resolution, and low sensitivity to polarized light. Moreover, the geometry is applicable to a wide range of scientific instruments that require both high SNR (signal-to-noise ratio) and low sensitivity to polarized scenes

Assessment of the Extent of Land Deformation Associated with Salt Domes within the Jazan City and Surroundings, Saudi Arabia

NASA Astrophysics Data System (ADS)

Pankratz, H. G.; Sultan, M.; Fathy, K.; AlMogren, S. M.; Harbi, H.; Sefry, S.; Emil, M.; Elkadiri, R.; Ahmed, M.; Othman, A.; Chouinard, K.

2016-12-01

The Jazan city in the Jazan Province of the Kingdom of Saudi Arabia is a vibrant and rapidly growing economic center and port. The old city of Jazan is centered over a salt dome (diaper) that crops out over an area, 3-4 km wide and 20 to 40 m above surroundings. The intrusion of the diaper into the overlying cap rock causes uneven surfaces, compromises building foundations, and causes infrastructural problems. Our study is aimed at the assessment of the salt dome-related land deformation. Using observations acquired over known locations of salt domes in Jazan and neighboring Farsan Islands, we identified criteria by which previously unidentified, near-surface salt domes, could be mapped. The selected criteria and/or applied methodologies included: (1) deformation over potential salt dome locations detected from Envisat, ERS-2, and Sentinel-1 scenes using the Stanford Method for Persistent Scatterers [StaMPs] and SARscape software. Uplift rates of about 3 mm/yr were observed over the salt dome outcrop in Jazan with increasing rates towards the center, indicating continuous rise of the salt diaper. (2) Local elevation highs over potential, near surface, salt dome intrusions observed in high spatial resolution (12.5 m), PALSAR digital elevation model (DEM). The elevation the Jazan dome is 45m high, whereas its surroundings are 15-30m high. (3) Negative Bouguer gravity anomalies over potential salt dome locations (Bouguer maps generated from 714 m interval airborne gravity data). Negative Bouguer anomalies were observed over the salt domes in Jazan (-3 mGal) and in Farsan (-30 mGal). (4) Boundaries of the potential salt domes extracted from zero tilt contour values on tilt derivative maps. (5) Shallow (< 2km) modeled depth to identified potential salt dome locations (software: Grav2dc 2-D modeling software). Zero contour values and 2-D modeling was used to identify the location and depth of the source anomaly (depth: Jazan = 0 m). (6) Spatial correlation (in a GIS

Analysis of Fault Spacing in Thrust-Belt Wedges Using Numerical Modeling

NASA Astrophysics Data System (ADS)

Regensburger, P. V.; Ito, G.

2017-12-01

Numerical modeling is invaluable in studying the mechanical processes governing the evolution of geologic features such as thrust-belt wedges. The mechanisms controlling thrust fault spacing in wedges is not well understood. Our numerical model treats the thrust belt as a visco-elastic-plastic continuum and uses a finite-difference, marker-in-cell method to solve for conservation of mass and momentum. From these conservation laws, stress is calculated and Byerlee's law is used to determine the shear stress required for a fault to form. Each model consists of a layer of crust, initially 3-km-thick, carried on top of a basal décollement, which moves at a constant speed towards a rigid backstop. A series of models were run with varied material properties, focusing on the angle of basal friction at the décollement, the angle of friction within the crust, and the cohesion of the crust. We investigate how these properties affected the spacing between thrusts that have the most time-integrated history of slip and therefore have the greatest effect on the large-scale undulations in surface topography. The surface position of these faults, which extend through most of the crustal layer, are identifiable as local maxima in positive curvature of surface topography. Tracking the temporal evolution of faults, we find that thrust blocks are widest when they first form at the front of the wedge and then they tend to contract over time as more crustal material is carried to the wedge. Within each model, thrust blocks form with similar initial widths, but individual thrust blocks develop differently and may approach an asymptotic width over time. The median of thrust block widths across the whole wedge tends to decrease with time. Median fault spacing shows a positive correlation with both wedge cohesion and internal friction. In contrast, median fault spacing exhibits a negative correlation at small angles of basal friction (<17˚) and a positive correlation with larger angles

Mathematical analysis of a sharp-diffuse interfaces model for seawater intrusion

NASA Astrophysics Data System (ADS)

Choquet, C.; Diédhiou, M. M.; Rosier, C.

2015-10-01

We consider a new model mixing sharp and diffuse interface approaches for seawater intrusion phenomena in free aquifers. More precisely, a phase field model is introduced in the boundary conditions on the virtual sharp interfaces. We thus include in the model the existence of diffuse transition zones but we preserve the simplified structure allowing front tracking. The three-dimensional problem then reduces to a two-dimensional model involving a strongly coupled system of partial differential equations of parabolic type describing the evolution of the depths of the two free surfaces, that is the interface between salt- and freshwater and the water table. We prove the existence of a weak solution for the model completed with initial and boundary conditions. We also prove that the depths of the two interfaces satisfy a coupled maximum principle.

Effect of climate change on sea water intrusion in coastal aquifers

NASA Astrophysics Data System (ADS)

Sherif, Mohsen M.; Singh, Vijay P.

1999-06-01

There is increasing debate these days on climate change and its possible consequences. Much of this debate has focused in the context of surface water systems. In many arid areas of the world, rainfall is scarce and so is surface runoff. These areas rely heavily on groundwater. The consequences of climate change on groundwater are long term and can be far reaching. One of the more apparent consequences is the increased migration of salt water inland in coastal aquifers. Using two coastal aquifers, one in Egypt and the other in India, this study investigates the effect of likely climate change on sea water intrusion. Three realistic scenarios mimicking climate change are considered. Under these scenarios, the Nile Delta aquifer is found to be more vulnerable to climate change and sea level rise.

Total knee arthroplasty after failed high tibial osteotomy: a systematic review of open versus closed wedge osteotomy.

PubMed

Han, Jae Hwi; Yang, Jae-Hyuk; Bhandare, Nikhl N; Suh, Dong Won; Lee, Jong Seong; Chang, Yong Suk; Yeom, Ji Woong; Nha, Kyung Wook

2016-08-01

Medial opening wedge high tibial osteotomy (HTO) has become increasingly popular as an alternative to lateral closing wedge osteotomy for the treatment of medial compartment knee osteoarthritis with varus deformity. The present systematic review was conducted to provide an objective analysis of total knee arthroplasty (TKA) outcomes following previous knee osteotomy (medial opening wedge vs. lateral closing wedge). A literature search of online databases (MEDLINE, EMBASE, Cochrane Library database) was made, in addition to manual search of major orthopaedic journals. The methodological quality of each of the studies was assessed on the Newcastle-Ottawa Scale and Effective Practice and Organization of Care. A total of ten studies were included in the review. There were eight studies with Level IV and two studies with Level III evidence. Eight studies reported clinical and radiologic scores. Comparative studies between TKA following medial opening and lateral closing wedge HTO did not demonstrate statistically significant clinical and radiologic differences. The revision rates were similar. However, more technical issues during TKA surgery after lateral closing wedge HTO were mentioned than the medial open wedge group. The quadriceps snip, tibial tubercle osteotomy, and lateral soft tissue release were more frequently needed in the lateral closing wedge HTO group. In addition, because of loss of proximal tibia bone geometry in the lateral closing wedge HTO group, concerns such as tibia stem impingement in the lateral tibial cortex was noted. The present systematic review suggests that TKA after medial opening and lateral closing wedge HTO showed similar performance. Clinical and radiologic outcome including revision rates did not statistically differ from included studies. However, there are more surgical technical concerns in TKA conversion from lateral closing wedge HTO than from the medial opening wedge HTO group. IV.

Rapid laccolith intrusion driven by explosive volcanic eruption

NASA Astrophysics Data System (ADS)

Castro, Jonathan M.; Cordonnier, Benoit; Schipper, C. Ian; Tuffen, Hugh; Baumann, Tobias S.; Feisel, Yves

2016-11-01

Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ~0.8 km3. Deformation and conduit flow models indicate laccolith depths of only ~20-200 m and overpressures (~1-10 MPa) that likely stemmed from conduit blockage. Our results show that explosive eruptions may rapidly force significant quantities of magma in the crust to build laccoliths. These iconic intrusions can thus be interpreted as eruptive features that pose unique and previously unrecognized volcanic hazards.

Rapid laccolith intrusion driven by explosive volcanic eruption.

PubMed

Castro, Jonathan M; Cordonnier, Benoit; Schipper, C Ian; Tuffen, Hugh; Baumann, Tobias S; Feisel, Yves

2016-11-23

Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ∼0.8 km 3 . Deformation and conduit flow models indicate laccolith depths of only ∼20-200 m and overpressures (∼1-10 MPa) that likely stemmed from conduit blockage. Our results show that explosive eruptions may rapidly force significant quantities of magma in the crust to build laccoliths. These iconic intrusions can thus be interpreted as eruptive features that pose unique and previously unrecognized volcanic hazards.

The influence of physical wedges on penumbra and in-field dose uniformity in ocular proton beams.

PubMed

Baker, Colin; Kacperek, Andrzej

2016-04-01

A physical wedge may be partially introduced into a proton beam when treating ocular tumours in order to improve dose conformity to the distal border of the tumour and spare the optic nerve. Two unwanted effects of this are observed: a predictable broadening of the beam penumbra on the wedged side of the field and, less predictably, an increase in dose within the field along a relatively narrow volume beneath the edge (toe) of the wedge, as a result of small-angle proton scatter. Monte Carlo simulations using MCNPX and direct measurements with radiochromic (GAFCHROMIC(®) EBT2) film were performed to quantify these effects for aluminium wedges in a 60 MeV proton beam as a function of wedge angle and position of the wedge relative to the patient. For extreme wedge angles (60° in eye tissue) and large wedge-to-patient distances (70 mm in this context), the 90-10% beam penumbra increased from 1.9 mm to 9.1 mm. In-field dose increases from small-angle proton scatter were found to contribute up to 21% additional dose, persisting along almost the full depth of the spread-out-Bragg peak. Profile broadening and in-field dose enhancement are both minimised by placing the wedge as close as possible to the patient. Use of lower atomic number wedge materials such as PMMA reduce the magnitude of both effects as a result of a reduced mean scattering angle per unit energy loss; however, their larger physical size and greater variation in density are undesirable. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Laser-based linear and nonlinear guided elastic waves at surfaces (2D) and wedges (1D).

PubMed

Hess, Peter; Lomonosov, Alexey M; Mayer, Andreas P

2014-01-01

The characteristic features and applications of linear and nonlinear guided elastic waves propagating along surfaces (2D) and wedges (1D) are discussed. Laser-based excitation, detection, or contact-free analysis of these guided waves with pump-probe methods are reviewed. Determination of material parameters by broadband surface acoustic waves (SAWs) and other applications in nondestructive evaluation (NDE) are considered. The realization of nonlinear SAWs in the form of solitary waves and as shock waves, used for the determination of the fracture strength, is described. The unique properties of dispersion-free wedge waves (WWs) propagating along homogeneous wedges and of dispersive wedge waves observed in the presence of wedge modifications such as tip truncation or coatings are outlined. Theoretical and experimental results on nonlinear wedge waves in isotropic and anisotropic solids are presented. Copyright © 2013 Elsevier B.V. All rights reserved.

Calibration of the Wedge Prism

Treesearch

Charles B. Briscoe

1957-01-01

Since the introduction of plotless cruising in this country by Grosenbaugh and the later suggestion of using a wedge prism as an angle gauge by Bruce this method of determining basal area has been widely adopted in the South. One of the factors contributing to the occasionally unsatisfactory results obtained is failure to calibrate the prism used. As noted by Bruce the...

What happens to full-f gyrokinetic transport and turbulence in a toroidal wedge simulation?

DOE PAGES

Kim, Kyuho; Chang, C. S.; Seo, Janghoon; ...

2017-01-24

Here, in order to save the computing time or to fit the simulation size into a limited computing hardware in a gyrokinetic turbulence simulation of a tokamak plasma, a toroidal wedge simulation may be utilized in which only a partial toroidal section is modeled with a periodic boundary condition in the toroidal direction. The most severe restriction in the wedge simulation is expected to be in the longest wavelength turbulence, i.e., ion temperature gradient (ITG) driven turbulence. The global full-f gyrokinetic code XGC1 is used to compare the transport and turbulence properties from a toroidal wedge simulation against the fullmore » torus simulation in an ITG unstable plasma in a model toroidal geometry. It is found that (1) the convergence study in the wedge number needs to be conducted all the way down to the full torus in order to avoid a false convergence, (2) a reasonably accurate simulation can be performed if the correct wedge number N can be identified, (3) the validity of a wedge simulation may be checked by performing a wave-number spectral analysis of the turbulence amplitude |δΦ| and assuring that the variation of δΦ between the discrete kθ values is less than 25% compared to the peak |δΦ|, and (4) a frequency spectrum may not be used for the validity check of a wedge simulation.« less

What happens to full-f gyrokinetic transport and turbulence in a toroidal wedge simulation?

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

Kim, Kyuho; Chang, C. S.; Seo, Janghoon

Here, in order to save the computing time or to fit the simulation size into a limited computing hardware in a gyrokinetic turbulence simulation of a tokamak plasma, a toroidal wedge simulation may be utilized in which only a partial toroidal section is modeled with a periodic boundary condition in the toroidal direction. The most severe restriction in the wedge simulation is expected to be in the longest wavelength turbulence, i.e., ion temperature gradient (ITG) driven turbulence. The global full-f gyrokinetic code XGC1 is used to compare the transport and turbulence properties from a toroidal wedge simulation against the fullmore » torus simulation in an ITG unstable plasma in a model toroidal geometry. It is found that (1) the convergence study in the wedge number needs to be conducted all the way down to the full torus in order to avoid a false convergence, (2) a reasonably accurate simulation can be performed if the correct wedge number N can be identified, (3) the validity of a wedge simulation may be checked by performing a wave-number spectral analysis of the turbulence amplitude |δΦ| and assuring that the variation of δΦ between the discrete kθ values is less than 25% compared to the peak |δΦ|, and (4) a frequency spectrum may not be used for the validity check of a wedge simulation.« less

A possible mechanism for earthquakes found in the mantle wedge of the Nazca subduction zone

NASA Astrophysics Data System (ADS)

Warren, L. M.; Chang, Y.; Prieto, G. A.

2017-12-01

Beneath Colombia, the Cauca cluster of intermediate-depth earthquakes extends for 200 km along the trench (3.5°N-5.5°N, 77.0°W-75.3°W) and, with 58 earthquakes per year with local magnitude ML >= 2.5, has a higher rate of seismicity than the subduction zone immediately to the north or south. By precisely locating 433 cluster earthquakes from 1/2010-3/2014 with data from the Colombian National Seismic Network, we found that the earthquakes are located both in a continuous Nazca plate subducting at an angle of 33°-43° and in the overlying mantle wedge. The mantle wedge earthquakes (12% of the earthquakes) form two isolated 40-km-tall columns extending perpendicular to the subducting slab. Using waveform inversion, we computed focal mechanisms for 69 of the larger earthquakes. The focal mechanisms are variable, but the intraslab earthquakes are generally consistent with an in-slab extensional stress axis oriented 25° counterclockwise from the down-dip direction. We suggest that the observed mantle wedge earthquakes are the result of hydrofracture in a relatively cool mantle wedge. This segment of the Nazca Plate is currently subducting at a normal angle, but Wagner et al. (2017) suggested that a flat slab slowly developed in the region between 9-5.9 Ma and persisted until 4 Ma. During flat slab subduction, the overlying mantle wedge typically cools because it is cut off from mantle corner flow. After hydrous minerals in the slab dehydrate, the dehydrated fluid is expelled from the slab and migrates through the mantle wedge. If a cool mantle wedge remains today, fluid dehydrated from the slab may generate earthquakes by hydrofracture, with the mantle wedge earthquakes representing fluid migration pathways. Dahm's (2000) model of water-filled fracture propagation in the mantle wedge shows hydrofractures propagating normal to the subducting slab and extending tens of km into the mantle wedge, as we observe.

Thermal Evolution of Diapirs with Complex Mantle Wedge Flow

NASA Astrophysics Data System (ADS)

Sylvia, R. T.; Kincaid, C.

2016-12-01

Subduction of oceanic lithosphere drives heat and mass exchange between Earth's interior and surface. One proposed transport mechanism for thermally and chemically distinct material through the wedge is the diapir model. The dominant driver of flow in the upper mantle is a mode of forced convection responding to motion of a tabular slab. A set of 4D laboratory experiments was conducted exploring the relationship between buoyancy flux and subduction parameters and subsequent effects on diapir transport. Variable subduction styles tested include downdip and rollback motion, slab gaps, slab steepening and backarc extension. The mantle is modeled using viscous glucose syrup with an Arrhenius type temperature dependent viscosity. Diapirs representing homogeneous mechanically mixed melange layer are introduced as buoyant fluid injected at multiple point sources situated along the surface of the sinking slab. Laboratory data is collected using high definition time-lapse photography and quantified using image velocimetry techniques. Here we present results from numerical simulation of the thermal evolution of spherical mantle wedge diapirs using 2D axisymmetric advection-diffusion model with internal diapir flow described by an analytic potential flow solution. A suite of wedge temperature profiles are used as thermal forcing on diapirs traversing the wedge along experimentally observed 4D ascent pathways. Scaling arguments suggest that for systems with Péclet number on the order of 15 advective heat transport is expected to dominate over diffusive heat transport, but the range of observed P-T-t paths and vigorous internal flow complicate this assumption. Interactions between modes of free (diapiric) and forced (wedge) convection lead to complex spatio-temporal variability in slab-to-arc connectivity patterns. Rollback induced toroidal flow, along trench changes in dip, convergence rate and backarc extension all produce a significant ( 500 km) trench-parallel transport

Young women's experiences of intrusive behavior in 12 countries.

PubMed

Sheridan, Lorraine; Scott, Adrian J; Roberts, Karl

2016-01-01

The present study provides international comparisons of young women's (N = 1,734) self-reported experiences of intrusive activities enacted by men. Undergraduate psychology students from 12 countries (Armenia, Australia, England, Egypt, Finland, India, Indonesia, Italy, Japan, Portugal, Scotland, and Trinidad) indicated which of 47 intrusive activities they had personally experienced. Intrusive behavior was not uncommon overall, although large differences were apparent between countries when women's personal experiences of specific intrusive activities were compared. Correlations were carried out between self-reported intrusive experiences, the Gender Empowerment Measure (GEM), and Hofstede's dimensions of national cultures. The primary associations were between women's experiences of intrusive behavior and the level of power they are afforded within the 12 countries. Women from countries with higher GEM scores reported experiencing more intrusive activities relating to courtship and requests for sex, while the experiences of women from countries with lower GEM scores related more to monitoring and ownership. Intrusive activities, many of them constituent of harassment and stalking, would appear to be widespread and universal, and their incidence and particular form reflect national level gender inequalities. © 2015 Wiley Periodicals, Inc.

Surgical quality of wedge resection affects overall survival in patients with early stage non-small cell lung cancer.

PubMed

Ajmani, Gaurav S; Wang, Chi-Hsiung; Kim, Ki Wan; Howington, John A; Krantz, Seth B

2018-07-01

Very few studies have examined the quality of wedge resection in patients with non-small cell lung cancer. Using the National Cancer Database, we evaluated whether the quality of wedge resection affects overall survival in patients with early disease and how these outcomes compare with those of patients who receive stereotactic radiation. We identified 14,328 patients with cT1 to T2, N0, M0 disease treated with wedge resection (n = 10,032) or stereotactic radiation (n = 4296) from 2005 to 2013 and developed a subsample of propensity-matched wedge and radiation patients. Wedge quality was grouped as high (negative margins, >5 nodes), average (negative margins, ≤5 nodes), and poor (positive margins). Overall survival was compared between patients who received wedge resection of different quality and those who received radiation, adjusting for demographic and clinical variables. Among patients who underwent wedge resection, 94.6% had negative margins, 44.3% had 0 nodes examined, 17.1% had >5 examined, and 3.0% were nodally upstaged; 16.7% received a high-quality wedge, which was associated with a lower risk of death compared with average-quality resection (adjusted hazard ratio [aHR], 0.74; 95% confidence interval [CI], 0.67-0.82). Compared with stereotactic radiation, wedge patients with negative margins had significantly reduced hazard of death (>5 nodes: aHR, 0.50; 95% CI, 0.43-0.58; ≤5 nodes: aHR, 0.65; 95% CI, 0.60-0.70). There was no significant survival difference between margin-positive wedge and radiation. Lymph nodes examined and margins obtained are important quality metrics in wedge resection. A high-quality wedge appears to confer a significant survival advantage over lower-quality wedge and stereotactic radiation. A margin-positive wedge appears to offer no benefit compared with radiation. Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Research on IPv6 intrusion detection system Snort-based

NASA Astrophysics Data System (ADS)

Shen, Zihao; Wang, Hui

2010-07-01

This paper introduces the common intrusion detection technologies, discusses the work flow of Snort intrusion detection system, and analyzes IPv6 data packet encapsulation and protocol decoding technology. We propose the expanding Snort architecture to support IPv6 intrusion detection in accordance with CIDF standard combined with protocol analysis technology and pattern matching technology, and present its composition. The research indicates that the expanding Snort system can effectively detect various intrusion attacks; it is high in detection efficiency and detection accuracy and reduces false alarm and omission report, which effectively solves the problem of IPv6 intrusion detection.

Intrusion-based reasoning and depression: cross-sectional and prospective relationships.

PubMed

Berle, David; Moulds, Michelle L

2014-01-01

Intrusion-based reasoning refers to the tendency to form interpretations about oneself or a situation based on the occurrence of a negative intrusive autobiographical memory. Intrusion-based reasoning characterises post-traumatic stress disorder, but has not yet been investigated in depression. We report two studies that aimed to investigate this. In Study 1 both high (n = 42) and low (n = 28) dysphoric participants demonstrated intrusion-based reasoning. High-dysphoric individuals engaged in self-referent intrusion-based reasoning to a greater extent than did low-dysphoric participants. In Study 2 there were no significant differences in intrusion-based reasoning between currently depressed (n = 27) and non-depressed (n = 51) participants, and intrusion-based reasoning did not predict depressive symptoms at 6-month follow-up. Interestingly, previously (n = 26) but not currently (n = 27) depressed participants engaged in intrusion-based reasoning to a greater extent than never-depressed participants (n = 25), indicating the possibility that intrusion-based reasoning may serve as a "scar" from previous episodes. The implications of these findings are discussed.

An automatically tuning intrusion detection system.

PubMed

Yu, Zhenwei; Tsai, Jeffrey J P; Weigert, Thomas

2007-04-01

An intrusion detection system (IDS) is a security layer used to detect ongoing intrusive activities in information systems. Traditionally, intrusion detection relies on extensive knowledge of security experts, in particular, on their familiarity with the computer system to be protected. To reduce this dependence, various data-mining and machine learning techniques have been deployed for intrusion detection. An IDS is usually working in a dynamically changing environment, which forces continuous tuning of the intrusion detection model, in order to maintain sufficient performance. The manual tuning process required by current systems depends on the system operators in working out the tuning solution and in integrating it into the detection model. In this paper, an automatically tuning IDS (ATIDS) is presented. The proposed system will automatically tune the detection model on-the-fly according to the feedback provided by the system operator when false predictions are encountered. The system is evaluated using the KDDCup'99 intrusion detection dataset. Experimental results show that the system achieves up to 35% improvement in terms of misclassification cost when compared with a system lacking the tuning feature. If only 10% false predictions are used to tune the model, the system still achieves about 30% improvement. Moreover, when tuning is not delayed too long, the system can achieve about 20% improvement, with only 1.3% of the false predictions used to tune the model. The results of the experiments show that a practical system can be built based on ATIDS: system operators can focus on verification of predictions with low confidence, as only those predictions determined to be false will be used to tune the detection model.

Rainfall induced groundwater mound in wedge-shaped promontories: The Strack-Chernyshov model revisited

NASA Astrophysics Data System (ADS)

Kacimov, A. R.; Kayumov, I. R.; Al-Maktoumi, A.

2016-11-01

An analytical solution to the Poisson equation governing Strack's discharge potential (squared thickness of a saturated zone in an unconfined aquifer) is obtained in a wedge-shaped domain with given head boundary conditions on the wedge sides (specified water level in an open water body around a porous promontory). The discharge vector components, maximum elevation of the water table in promontory vertical cross-sections, quantity of groundwater seeping through segments of the wedge sides, the volume of fresh groundwater in the mound are found. For acute angles, the solution to the problem is non-unique and specification of the behaviour at infinity is needed. A ;basic; solution is distinguished, which minimizes the water table height above a horizontal bedrock. MODFLOW simulations are carried out in a finite triangular island and compare solutions with a constant-head, no-flow and ;basic; boundary condition on one side of the triangle. Far from the tip of an infinite-size promontory one has to be cautious with truncation of the simulated flow domains and imposing corresponding boundary conditions. For a right and obtuse wedge angles, there are no positive solutions for the case of constant accretion on the water table. In a particular case of a confined rigid wedge-shaped aquifer and incompressible fluid, from an explicit solution to the Laplace equation for the hydraulic head with arbitrary time-space varying boundary conditions along the promontory rays, essentially 2-D transient Darcian flows within the wedge are computed. They illustrate that surface water waves on the promontory boundaries can generate strong Darcian waves inside the porous wedge. Evaporation from the water table and sea-water intruded interface (rather than a horizontal bed) are straightforward generalizations for the Poissonian Strack potential.

SU-E-T-178: Clinical Feasibility of Multi-Leaf Collimator Based Dynamic Wedge

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

Jeong, C; Kwak, J; Ahn, S

2015-06-15

Purpose: A multi-leaf collimator (MLC) based dynamic wedge (MDW), which provide similar dose profile of physical wedge (PW) along x-jaw direction while significant monitor unit (MU) reduction, was developed and investigated for clinical use. Methods: A novel technique was used to create the wedge profile using MLC. A modification was applied to the DICOM-RT format file of the plan made with the PW to replace PW with MDW. The Varian enhanced dynamic wedge profile was used to produce MLC sequence, while the MU of the wedged field was recalculated using PW factor and fluence map. The profiles for all possiblemore » MDWs to substitute PWs were verified in 6/15 MV x-ray irradiations. New plans with MDWs were compared with the original plans in 5 rectal, 5 RT breast and 5 liver cases. Results: The wedge profile of the MDW fields were well matched with those of PWs inside the fields while less scatter than PW out of the fields. For plan comparisons of the clinical cases no significant dose discrepancy was observed between MDW plan and PW’s with the dose volume histograms. The maximum and mean doses in PTVs are agreed within 1.0%. The Result of OARs of MDW plans are slightly improved in the maximum doses (3.22 ∼ 150.4 cGy) and the mean doses (17.18 ∼ 85.52 cGy) on average for all cases while the prescribed doses are 45 Gy for rectal cases, 40 or 45 Gy for liver cases and 50 Gy for breast cases. The MUs of the fields which replace PW with MDW are reduced to 68% of those of PW. Conclusion: We developed a novel dynamic wedge technique with MLC that shows clinical advantage compared to PW.« less

Induction of thermotropic bicontinuous cubic phases in liquid-crystalline ammonium and phosphonium salts.

PubMed

Ichikawa, Takahiro; Yoshio, Masafumi; Hamasaki, Atsushi; Taguchi, Satomi; Liu, Feng; Zeng, Xiang-bing; Ungar, Goran; Ohno, Hiroyuki; Kato, Takashi

2012-02-08

Two series of wedge-shaped onium salts, one ammonium and the other phosphonium, having 3,4,5-tris(alkyloxy)benzyl moieties, exhibit thermotropic bicontinuous "gyroid" cubic (Cub(bi)) and hexagonal columnar liquid-crystalline (LC) phases by nanosegregation between ionophilic and ionophobic parts. The alkyl chain lengths on the cationic moieties, anion species, and alkyl chain lengths on the benzyl moieties have crucial effects on their thermotropic phase behavior. For example, triethyl-[3,4,5-tris(dodecyloxy)benzyl]ammonium hexafluorophosphate forms the thermotropic Ia3d Cub(bi) LC phase, whereas an analogous compound with trifluoromethanesulfonate anion shows no LC properties. Synchrotron small-angle diffraction intensities from the Ia3d Cub(bi) LC materials provide electron density maps in the bulk state. The resulting maps show convincingly that the Ia3d Cub(bi) structure is composed of three-dimensionally interconnected ion nanochannel networks surrounded by aliphatic domains. A novel differential mapping technique has been applied successfully. The map of triethyl-[3,4,5-tris(decyloxy)benzyl]ammonium tetrafluoroborate has been subtracted from that of the analogous ammonium salt with hexafluorophosphate anion in the Ia3d Cub(bi) phases. The differential map shows that the counteranions are located in the core of the three-dimensionally interconnected nanochannel networks. Changing from trimethyl- via triethyl- to tripropylammonium cation changes the phase from columnar to Cub(bi) to no mesophase, respectively. This sensitivity to the widened shape for the narrow end of the molecule is explained successfully by the previously proposed semiquantitative geometric model based on the radial distribution of volume in wedge-shaped molecules. The LC onium salts dissolve lithium tetrafluoroborate without losing the Ia3d Cub(bi) LC phase. The Cub(bi) LC materials exhibit efficient ion-transporting behavior as a result of their 3D interconnected ion nanochannel networks

Intrusion Detection in Control Systems using Sequence Characteristics

NASA Astrophysics Data System (ADS)

Kiuchi, Mai; Onoda, Takashi

Intrusion detection is considered effective in control systems. Sequences of the control application behavior observed in the communication, such as the order of the control device to be controlled, are important in control systems. However, most intrusion detection systems do not effectively reflect sequences in the application layer into the detection rules. In our previous work, we considered utilizing sequences for intrusion detection in control systems, and demonstrated the usefulness of sequences for intrusion detection. However, manually writing the detection rules for a large system can be difficult, so using machine learning methods becomes feasible. Also, in the case of control systems, there have been very few observed cyber attacks, so we have very little knowledge of the attack data that should be used to train the intrusion detection system. In this paper, we use an approach that combines CRF (Conditional Random Field) considering the sequence of the system, thus able to reflect the characteristics of control system sequences into the intrusion detection system, and also does not need the knowledge of attack data to construct the detection rules.

Rapid laccolith intrusion driven by explosive volcanic eruption

PubMed Central

Castro, Jonathan M.; Cordonnier, Benoit; Schipper, C. Ian; Tuffen, Hugh; Baumann, Tobias S.; Feisel, Yves

2016-01-01

Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ∼0.8 km3. Deformation and conduit flow models indicate laccolith depths of only ∼20–200 m and overpressures (∼1–10 MPa) that likely stemmed from conduit blockage. Our results show that explosive eruptions may rapidly force significant quantities of magma in the crust to build laccoliths. These iconic intrusions can thus be interpreted as eruptive features that pose unique and previously unrecognized volcanic hazards. PMID:27876800

Effect of Shockwave Curvature on Run Distance Observed with a Modified Wedge Test

NASA Astrophysics Data System (ADS)

Lee, Richard; Dorgan, Robert; Sutherland, Gerrit; Benedetta, Ashley; Milby, Christopher

2011-06-01

The effect of wave curvature on shock initiation in PBXN-110 was investigated using a modified wedge test configuration. Various thicknesses of PBXN-110 donor slabs were used to define the shockwave curvature introduced to wedge samples of the same explosive. The donor slabs were initiated with line-wave generators so that the introduced shock would be the same shape, magnitude and duration across the entire input surface of the wedge. The shock parameters were varied for a given donor thickness via different widths of PMMA spacers placed between the donor and the wedge. A framing camera was used to observe where initiation occurred along the face of the wedge. Initiation always occurred at the center of the shock front instead of the sides like that reported by others using a much smaller test format. Results were compared to CTH calculations to indicate if there were effects associated with highly curved shock fronts that could not be adequately predicted. The run distance predicted in CTH for a 50.8 mm thick donor slab (low curvature) compared favorably with experimental results. However, results from thinner donor slabs (higher curvature) indicate a more sensitive behavior than the simulations predicted.

Controlling direct contact force for wet adhesion with different wedged film stabilities

NASA Astrophysics Data System (ADS)

Li, Meng; Xie, Jun; Shi, Liping; Huang, Wei; Wang, Xiaolei

2018-04-01

In solid–liquid–solid adhesive systems, wedged films often feature instability at microscopic thicknesses, which can easily disrupt the adhesive strength of their remarkable direct contact force. Here, sodium dodecyl sulfate (SDS) was employed to tune the instability of adhesion in wedged glass–water–rubber films, achieving controllable direct contact. Experimental results showed that the supplement of SDS molecules significantly weakened the direct contact force for wet adhesion and eliminated it at high concentrations. The underlying reason was suggested to be the repulsive double-layer force caused by SDS molecules, which lowers the instability of the wedged film and balances the preload, disrupting the direct contact in wet adhesion.

Physical optics-based diffraction coefficient for a wedge with different face impedances.

PubMed

Umul, Yusuf Ziya

2018-03-20

A new diffraction field expression is introduced with the aid of the modified theory of physical optics for a wedge with different face impedances. First, the scattered geometrical optics fields are determined when both faces of the wedge are illuminated by the incident wave. The geometrical optics waves are then expressed in terms of the sum of two different fields that occur for different impedance wedges. The diffracted fields are determined for the two cases separately, and the total diffracted field is obtained as a sum of these waves. Lastly, the uniform field expressions are obtained, and the resultant fields are numerically compared with the solution of Maliuzhinets.

How to predict deformation for geometrically and mechanically non-uniform accretionary wedges

NASA Astrophysics Data System (ADS)

Souloumiac, Pauline; Cubas, Nadaya; Caër, Typhaine

2017-04-01

The mechanical understanding of fold-and-thrust belts and accretionary prisms strongly relies on the critical taper theory (CTT). The latter considers their mechanics as analogous to sand pushed by a moving bulldozer along a frictional décollement. The wedge evolves into a critical geometry, corresponding to a point of internal state of stress for which the whole wedge including the basal décollement is on the verge of Coulomb failure. If the décollement is planar and material properties are homogeneous and cohesionless, the critical wedge is triangular. The force of the CCT relies on the fact that conditions for stress equilibrium, Coulomb yielding of the wedge and basal frictional sliding have an analytical solution. However, this theory suffers from several limits. As stated above, the analytical solution applies for perfectly triangular wedges. However, the critical taper is shaped by internal thrusts that lead to a non-uniform topographic slope. What is then the scale of topographic variability for which the CCT will stand? The second limit is that CCT applies for homogeneous frictional properties in the wedge and as well as along the décollement. We can also wonder if there is a scaling parameter for which variations of properties along the decollement would impact the topography. We here show how the limit analysis, an efficient semi-analytical approach, can help us to overcome these limits. We aim to provide simple analytical solutions to structural geologists to evaluate the critical state of their field study cases. We first show that the effect of topographic slope variability relies on a competition between the surface of potential hanging-walls and the surface of theoretical critical hanging-walls. Dips of thrust and backthrust are controlled by the frictional parameters. Along a wedge with a non-regular topography, an out-of-sequence system will appear if there is a position along the wedge for which the hanging-wall will have a lower surface than

Analysis of coal seam thickness and seismic wave amplitude: A wedge model

NASA Astrophysics Data System (ADS)

Zou, Guangui; Xu, Zhiliang; Peng, Suping; Fan, Feng

2018-01-01

Coal seam thickness is of great significance in mining coal resources. The focus of this study is to determine the relationship between coal seam thickness and seismic wave amplitude, and the factors influencing this relationship. We used a wedge model to analyze this relationship and its influencing factors. The results show that wave interference from the top and bottom interfaces is the primary reason for the linear relationship between seismic wave amplitude and wedge thickness, when the thickness of the wedge is less than one quarter of the wavelength. This relationship is influenced by the dominant frequency, reflection coefficients from the top and bottom boundaries, depth, thickness, and angle of the wedge. However, when the lateral shift between the reflected waves is smaller than the radius of the first Fresnel zone, the wedge angle and change in lithology at the top and bottom layers are considered to have little effect on the amplitude of the interference wave. The difference in the dominant frequency of seismic waves can be reduced by filtering, and the linear relationship between amplitude and coal thickness can be improved. Field data from Sihe coal mine was analyzed, and the error was found to be within 4% of the predicted seismic wave amplitude. The above conclusions could help predict the thickness of coal seam by seismic amplitude.

Vapor Intrusion Characterization Report (Revision 1.0)

EPA Pesticide Factsheets

Vapor Intrusion Characterization Report (Revision 1) - February 5, 2015: This report, which was approved by the EPA on February 18, 2015, documents the results from implementation of the Final Vapor Intrusion Characterization Work Plan.

Intrusive Memories of Distressing Information: An fMRI Study

PubMed Central

Battaglini, Eva; Liddell, Belinda; Das, Pritha; Malhi, Gin; Felmingham, Kim

2016-01-01

Although intrusive memories are characteristic of many psychological disorders, the neurobiological underpinning of these involuntary recollections are largely unknown. In this study we used functional magentic resonance imaging (fMRI) to identify the neural networks associated with encoding of negative stimuli that are subsequently experienced as intrusive memories. Healthy partipants (N = 42) viewed negative and neutral images during a visual/verbal processing task in an fMRI context. Two days later they were assessed on the Impact of Event Scale for occurrence of intrusive memories of the encoded images. A sub-group of participants who reported significant intrusions (n = 13) demonstrated stronger activation in the amygdala, bilateral ACC and parahippocampal gyrus during verbal encoding relative to a group who reported no intrusions (n = 13). Within-group analyses also revealed that the high intrusion group showed greater activity in the dorsomedial (dmPFC) and dorsolateral prefrontal cortex (dlPFC), inferior frontal gyrus and occipital regions during negative verbal processing compared to neutral verbal processing. These results do not accord with models of intrusions that emphasise visual processing of information at encoding but are consistent with models that highlight the role of inhibitory and suppression processes in the formation of subsequent intrusive memories. PMID:27685784

Geochemistry and field geology of shoshonitic magmas in the Late Cretaceous foreland fold and thrust belt of southwestern Montana: Results from the North Doherty Mountain Intrusive Complex

NASA Astrophysics Data System (ADS)

Beranek, L. P.; Burton, B. R.; Ihinger, P. D.

2002-12-01

The North Doherty Mountain Intrusive Complex (NDMIC) is one of several satellite plutons related to the areally extensive Boulder batholith of southwestern Montana. The Boulder batholith comprises multiple plutons and intrusive phases, and the magmatism has long been thought to be the result of subduction due to its calc-alkaline granodioritic composition. The batholith is situated in the Helena salient, which differs from other parts of the North American Cordilleran foreland because there, magmatism spatially and temporally overlaps with deformation in the foreland fold and thrust belt. The North Doherty Mountain Intrusive Complex (NDMIC) is one of several satellite plutons related to the Boulder batholith and represents an ideal microcosm of the batholith for petrogenetic and structural studies because it exposes both mafic and felsic units and was emplaced in the limb of a major thrust related fold. We present new geologic mapping and detailed trace element geochemical analyses to show that the entire mafic-to-felsic suite of rocks in the NDMIC are cogenetic and shoshonitic in character. Shoshonites are unusual magmas that are distinguished by their high concentrations of K, Rb, Sr, Ba, Zr, and Th contents, and are thought to represent partial melting at great depths within the mantle wedge above a subducting slab. The presence of shoshonitic magma in the Cordilleran foreland fold and thrust belt provides important clues into the nature of the formation of this unusual magma type and can provide insights into our understanding of magmatism in foreland structural settings.

Analytical and numerical study of the salinity intrusion in the Sebou river estuary (Morocco) - effect of the "Super Blood Moon" (total lunar eclipse) of 2015

NASA Astrophysics Data System (ADS)

Haddout, Soufiane; Igouzal, Mohammed; Maslouhi, Abdellatif

2016-09-01

The longitudinal variation of salinity and the maximum salinity intrusion length in an alluvial estuary are important environmental concerns for policy makers and managers since they influence water quality, water utilization and agricultural development in estuarine environments and the potential use of water resources in general. The supermoon total lunar eclipse is a rare event. According to NASA, they have only occurred 5 times in the 1900s - in 1910, 1928, 1946, 1964 and 1982. After the 28 September 2015 total lunar eclipse, a Super Blood Moon eclipse will not recur before 8 October 2033. In this paper, for the first time, the impact of the combination of a supermoon and a total lunar eclipse on the salinity intrusion along an estuary is studied. The 28 September 2015 supermoon total lunar eclipse is the focus of this study and the Sebou river estuary (Morocco) is used as an application area. The Sebou estuary is an area with high agricultural potential, is becoming one of the most important industrial zones in Morocco and it is experiencing a salt intrusion problem. Hydrodynamic equations for tidal wave propagation coupled with the Savenije theory and a numerical salinity transport model (HEC-RAS software "Hydrologic Engineering Center River Analysis System") are applied to study the impact of the supermoon total lunar eclipse on the salinity intrusion. Intensive salinity measurements during this extreme event were recorded along the Sebou estuary. Measurements showed a modification of the shape of axial salinity profiles and a notable water elevation rise, compared with normal situations. The two optimization parameters (Van der Burgh's and dispersion coefficients) of the analytical model are estimated based on the Levenberg-Marquardt's algorithm (i.e., solving nonlinear least-squares problems). The salinity transport model was calibrated and validated using field data. The results show that the two models described very well the salt intrusion during the

WEDGE ABSORBERS FOR MUON COOLING WITH A TEST BEAM AT MICE

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

Neuffer, David; Acosta, J.; Summers, D.

2016-10-18

Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

Effect of Foot Progression Angle and Lateral Wedge Insole on a Reduction in Knee Adduction Moment.

PubMed

Tokunaga, Ken; Nakai, Yuki; Matsumoto, Ryo; Kiyama, Ryoji; Kawada, Masayuki; Ohwatashi, Akihiko; Fukudome, Kiyohiro; Ohshige, Tadasu; Maeda, Tetsuo

2016-10-01

This study evaluated the effect of foot progression angle on the reduction in knee adduction moment caused by a lateral wedged insole during walking. Twenty healthy, young volunteers walked 10 m at their comfortable velocity wearing a lateral wedged insole or control flat insole in 3 foot progression angle conditions: natural, toe-out, and toe-in. A 3-dimensional rigid link model was used to calculate the external knee adduction moment, the moment arm of ground reaction force to knee joint center, and the reduction ratio of knee adduction moment and moment arm. The result indicated that the toe-out condition and lateral wedged insole decreased the knee adduction moment in the whole stance phase. The reduction ratio of the knee adduction moment and the moment arm exhibited a close relationship. Lateral wedged insoles decreased the knee adduction moment in various foot progression angle conditions due to decrease of the moment arm of the ground reaction force. Moreover, the knee adduction moment during the toe-out gait with lateral wedged insole was the smallest due to the synergistic effect of the lateral wedged insole and foot progression angle. Lateral wedged insoles may be a valid intervention for patients with knee osteoarthritis regardless of the foot progression angle.

Assessment of Mitigation Systems on Vapor Intrusion ...

EPA Pesticide Factsheets

Vapor intrusion is the migration of subsurface vapors, including radon and volatile organic compounds (VOCs), in soil gas from the subsurface to indoor air. Vapor intrusion happens because there are pressure and concentration differentials between indoor air and soil gas. Indoor environments are often negatively pressurized with respect to outdoor air and soil gas (for example, from exhaust fans or the stack effect), and this pressure difference allows soil gas containing subsurface vapors to flow into indoor air through advection. In addition, concentration differentials cause VOCs and radon to migrate from areas of higher to lower concentrations through diffusion, which is another cause of vapor intrusion. Current practice for evaluating the vapor intrusion pathway involves a multiple line of evidence approach based on direct measurements in groundwater, external soil gas, subslab soil gas, and/or indoor air. No single line of evidence is considered definitive, and direct measurements of vapor intrusion can be costly, especially where significant spatial and temporal variability require repeated measurements at multiple locations to accurately assess the chronic risks of long-term exposure to volatile organic compounds (VOCs) like chloroform, perchloroethylene (PCE), and trichloroethylene (TCE).

Spacing of Imbricated Thrust Faults and the Strength of Thrust-Belts and Accretionary Wedges

NASA Astrophysics Data System (ADS)

Ito, G.; Regensburger, P. V.; Moore, G. F.

2017-12-01

The pattern of imbricated thrust blocks is a prominent characteristic of the large-scale structure of thrust-belts and accretionary wedges around the world. Mechanical models of these systems have a rich history from laboratory analogs, and more recently from computational simulations, most of which, qualitatively reproduce the regular patterns of imbricated thrusts seen in nature. Despite the prevalence of these patterns in nature and in models, our knowledge of what controls the spacing of the thrusts remains immature at best. We tackle this problem using a finite difference, particle-in-cell method that simulates visco-elastic-plastic deformation with a Mohr-Coulomb brittle failure criterion. The model simulates a horizontal base that moves toward a rigid vertical backstop, carrying with it an overlying layer of crust. The crustal layer has a greater frictional strength than the base, is cohesive, and is initially uniform in thickness. As the layer contracts, a series of thrust blocks immerge sequentially and form a wedge having a mean taper consistent with that predicted by a noncohesive, critical Coulomb wedge. The widths of the thrust blocks (or spacing between adjacent thrusts) are greatest at the front of the wedge, tend to decrease with continued contraction, and then tend toward a pseudo-steady, minimum width. Numerous experiments show that the characteristic spacing of thrusts increases with the brittle strength of the wedge material (cohesion + friction) and decreases with increasing basal friction for low (<8°) taper angles. These relations are consistent with predictions of the elastic stresses forward of the frontal thrust and at what distance the differential stress exceeds the brittle threshold to form a new frontal thrust. Hence the characteristic spacing of the thrusts across the whole wedge is largely inherited at the very front of the wedge. Our aim is to develop scaling laws that will illuminate the basic physical processes controlling

Vertebral body or intervertebral disc wedging: which contributes more to thoracolumbar kyphosis in ankylosing spondylitis patients?: A retrospective study.

PubMed

Liu, Hao; Qian, Bang-Ping; Qiu, Yong; Wang, Yan; Wang, Bin; Yu, Yang; Zhu, Ze-Zhang

2016-09-01

Both vertebral body wedging and disc wedging are found in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis. However, their relative contribution to thoracolumbar kyphosis is not fully understood. The objective of this study was to compare different contributions of vertebral and disc wedging to the thoracolumbar kyphosis in AS patients, and to analyze the relationship between the apical vertebral wedging angle and thoracolumbar kyphosis.From October 2009 to October 2013, a total of 59 consecutive AS patients with thoracolumbar kyphosis with a mean age of 38.1 years were recruited in this study. Based on global kyphosis (GK), 26 patients with GK < 70° were assigned to group A, and the other 33 patients with GK ≥ 70° were included in group B. Each GK was divided into disc wedge angles and vertebral wedge angles. The wedging angle of each disc and vertebra comprising the thoracolumbar kyphosis was measured, and the proportion of the wedging angle to the GK was calculated accordingly. Intergroup and intragroup comparisons were subsequently performed to investigate the different contributions of disc and vertebra to the GK. The correlation between the apical vertebral wedging angle and GK was calculated by Pearson correlation analysis. The duration of disease and sex were also recorded in this study.With respect to the mean disease duration, significant difference was observed between the two groups (P < 0.01). The wedging angle and wedging percentage of discs were significantly higher than those of vertebrae in group A (34.8° ± 2.5° vs 26.7° ± 2.7°, P < 0.01 and 56.6% vs 43.4%, P < 0.01), whereas disc wedging and disc wedging percentage were significantly lower than vertebrae in group B (37.6° ± 7.0° vs 50.1° ± 5.1°, P < 0.01 and 42.7% vs 57.3%, P < 0.01). The wedging of vertebrae was significantly higher in group B than in group A (50.1° ± 5.1° vs 26.7° ± 2.7°, P < 0

Effect of shockwave curvature on run distance observed with a modified wedge test

NASA Astrophysics Data System (ADS)

Lee, Richard; Dorgan, Robert J.; Sutherland, Gerrit; Benedetta, Ashley; Milby, Christopher

2012-03-01

The effect of wave curvature on shock initiation in PBXN-110 was investigated using a modified wedge test configuration. Various widths of PBXN-110 donor slabs were used to define the shockwave curvature introduced to wedge samples of the same explosive. The donor slabs were initiated with line-wave generators so that the shock from the donor would be the same shape, magnitude and duration across the entire input surface of the wedge. The shock parameters were varied for a given donor with PMMA spacers placed between the donor and the wedge sample. A high-speed electronic framing camera was used to observe where initiation occurred along the face of the wedge. Initiation always occurred at the center of the shock front instead of along the sides like that reported by others using a much smaller test format. Results were compared to CTH calculations to indicate if there were effects associated with highly curved shock fronts that could not be adequately predicted. The run distance predicted in CTH for a 50.8 mm wide donor slab (low curvature) compared favorably with experimental results. However, results from thinner donor slabs (higher curvature) indicate a more sensitive behavior than the simulations predicted.

Magmatic intrusions in the lunar crust

NASA Astrophysics Data System (ADS)

Michaut, C.; Thorey, C.

2015-10-01

The lunar highlands are very old, with ages covering a timespan between 4.5 to 4.2 Gyr, and probably formed by flotation of light plagioclase minerals on top of the lunar magma ocean. The lunar crust provides thus an invaluable evidence of the geological and magmatic processes occurring in the first times of the terrestrial planets history. According to the last estimates from the GRAIL mission, the lunar primary crust is particularly light and relatively thick [1] This low-density crust acted as a barrier for the dense primary mantle melts. This is particularly evident in the fact that subsequent mare basalts erupted primarily within large impact basin: at least part of the crust must have been removed for the magma to reach the surface. However, the trajectory of the magma from the mantle to the surface is unknown. Using a model of magma emplacement below an elastic overlying layer with a flexural wavelength Λ, we characterize the surface deformations induced by the presence of shallow magmatic intrusions. We demonstrate that, depending on its size, the intrusion can show two different shapes: a bell shape when its radius is smaller than 4 times Λ or a flat top with small bended edges if its radius is larger than 4 times Λ[2]. These characteristic shapes for the intrusion result in characteristic deformations at the surface that also depend on the topography of the layer overlying the intrusion [3].Using this model we provide evidence of the presence of intrusions within the crust of the Moon as surface deformations in the form of low-slope lunar domes and floor-fractured craters. All these geological features have morphologies consistent with models of magma spreading at depth and deforming an overlying elastic layer. Further more,at floor-fractured craters, the deformation is contained within the crater interior, suggesting that the overpressure at the origin of magma ascent and intrusion was less than the pressure due to the weight of the crust removed by

Metamorphic charnockite in contact aureoles around intrusive enderbite from Natal, South Africa

NASA Astrophysics Data System (ADS)

van den Kerkhof, Alfons M.; Grantham, Geoffrey H.

In the Port Edward area of southern Kwa-Zulu Natal, South Africa, charnockitic aureoles up to 10m in width in the normally garnetiferous Nicholson's Point Granite, are developed adjacent to intrusive contacts with the Port Edward Enderbite and anhydrous pegmatitic veins. Mineralogical differences between the country rock and charnockitic aureole suggest that the dehydration reaction Bt+Qtz-->Opx+Kfs+H2O and the reaction of Grt+Qtz-->Opx+Pl were responsible for the charnockitization. The compositions of fluid inclusions show systematic variation with: (1) the Port Edward Enderbite being dominated by CO2 and N2 fluid inclusions; (2) the non-charnockitized granite by saline aqueous inclusions with 18-23 EqWt% NaCl; (3) the charnockitic aureoles by low-salinity and pure water inclusions (<7 EqWt% NaCl); (4) the pegmatites by aqueous inclusions of various salinity with minor CO2. As a result of the thermal event the homogenization temperatures of the inclusions in charnockite show a much larger range (up to 390°C) compared to the fluid inclusions in granite (mostly <250°C). Contrary to fluid-controlled charnockitization (brines, CO2) which may have taken place along shear zones away from the intrusive body, the present ``proximal'' charnockitized granite formed directly at the contact with enderbite. The inclusions indicate contact metamorphism induced by the intrusion of ``dry'' enderbitic magma into ``wet'' granite resulting in local dehydration. This was confirmed by cathodoluminescence microscopy showing textures indicative for the local reduction of structural water in the charnockite quartz. Two-pyroxene thermometry on the Port Edward Enderbite suggests intrusion at temperatures of 1000-1050°C into country rock with temperature of <700°C. The temperature of aureole formation must have been between 700°C (breakdown of pyrite to form pyrrhotite) and 1000°C. Charnockitization was probably controlled largely by heat related to anhydrous intrusions causing

Corticostriatal circuitry in regulating diseases characterized by intrusive thinking

PubMed Central

Kalivas, Benjamin C.; Kalivas, Peter W.

2016-01-01

Intrusive thinking triggers clinical symptoms in many neuropsychiatric disorders. Using drug addiction as an exemplar disorder sustained in part by intrusive thinking, we explore studies demonstrating that impairments in corticostriatal circuitry strongly contribute to intrusive thinking. Neuroimaging studies have long implicated this projection in cue-induced craving to use drugs, and preclinical models show that marked changes are produced at corticostriatal synapses in the nucleus accumbens during a relapse episode. We delineate an accumbens microcircuit that mediates cue-induced drug seeking becoming an intrusive event. This microcircuit harbors many potential therapeutic targets. We focus on preclinical and clinical studies, showing that administering N-acetylcysteine restores uptake of synaptic glutamate by astroglial glutamate transporters and thereby inhibits intrusive thinking. We posit that because intrusive thinking is a shared endophenotype in many disorders, N-acetylcysteine has positive effects in clinical trials for a variety of neuropsychiatric disorders, including drug addiction, gambling, trichotillomania, and depression. PMID:27069381

Corticostriatal circuitry in regulating diseases characterized by intrusive thinking.

PubMed

Kalivas, Benjamin C; Kalivas, Peter W

2016-03-01

Intrusive thinking triggers clinical symptoms in many neuropsychiatric disorders. Using drug addiction as an exemplar disorder sustained in part by intrusive thinking, we explore studies demonstrating that impairments in corticostriatal circuitry strongly contribute to intrusive thinking. Neuroimaging studies have long implicated this projection in cue-induced craving to use drugs, and preclinical models show that marked changes are produced at corticostriatal synapses in the nucleus accumbens during a relapse episode. We delineate an accumbens microcircuit that mediates cue-induced drug seeking becoming an intrusive event. This microcircuit harbors many potential therapeutic targets. We focus on preclinical and clinical studies, showing that administering N-acetylcysteine restores uptake of synaptic glutamate by astroglial glutamate transporters and thereby inhibits intrusive thinking. We posit that because intrusive thinking is a shared endophenotype in many disorders, N-acetylcysteine has positive effects in clinical trials for a variety of neuropsychiatric disorders, including drug addiction, gambling, trichotillomania, and depression.

Measuring the reionization 21 cm fluctuations using clustering wedges

NASA Astrophysics Data System (ADS)

Raut, Dinesh; Choudhury, Tirthankar Roy; Ghara, Raghunath

2018-03-01

One of the main challenges in probing the reionization epoch using the redshifted 21 cm line is that the magnitude of the signal is several orders smaller than the astrophysical foregrounds. One of the methods to deal with the problem is to avoid a wedge-shaped region in the Fourier k⊥ - k∥ space which contains the signal from the spectrally smooth foregrounds. However, measuring the spherically averaged power spectrum using only modes outside this wedge (i.e. in the reionization window) leads to a bias. We provide a prescription, based on expanding the power spectrum in terms of the shifted Legendre polynomials, which can be used to compute the angular moments of the power spectrum in the reionization window. The prescription requires computation of the monopole, quadrupole, and hexadecapole moments of the power spectrum using the theoretical model under consideration and also the knowledge of the effective extent of the foreground wedge in the k⊥ - k∥ plane. One can then calculate the theoretical power spectrum in the window which can be directly compared with observations. The analysis should have implications for avoiding any bias in the parameter constraints using 21 cm power spectrum data.

Development of Cone Wedge Ring Expansion Test to Evaluate Mechanical Properties of Clad Tubing Structure

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

Wang, Jy-An John

To determine the hoop tensile properties of irradiated fuel cladding in a hot cell, a cone wedge ring expansion test method was developed. A four-piece wedge insert was designed with tapered angles matched to the cone shape of a loading piston. The ring specimen was expanded in the radial direction by the lateral expansion of the wedges under the downward movement of the piston. The advantages of the proposed method are that implementation of the test setup in a hot cell is simple and easy, and that it enables a direct strain measurement of the test specimen from the piston’smore » vertical displacement soon after the wedge-clad contact resistance is initiated.« less

49 CFR 215.113 - Defective plain bearing wedge.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not located...

49 CFR 215.113 - Defective plain bearing wedge.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not located...

49 CFR 215.113 - Defective plain bearing wedge.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not located...

49 CFR 215.113 - Defective plain bearing wedge.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not located...

49 CFR 215.113 - Defective plain bearing wedge.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components... car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not located...

Controls on intrusion of near-trench magmas of the Sanak-Baranof Belt, Alaska, during Paleogene ridge subduction, and consequences for forearc evolution

USGS Publications Warehouse

Kusky, Timothy M.; Bradley, Dwight C.; Donely, D. Thomas; Rowley, David; Haeussler, Peter J.

2003-01-01

A belt of Paleogene near-trench plutons known as the Sanak-Baranof belt intruded the southern Alaska convergent margin. A compilation of isotopic ages of these plutons shows that they range in age from 61 Ma in the west to ca. 50 Ma in the east. This migrating pulse of magmatism along the continental margin is consistent with North Pacific plate reconstructions that suggests the plutons were generated by migration of a trench-ridge-trench triple junction along the margin. On the Kenai Peninsula the regional lower greenschist metamorphic grade of the turbiditic host rocks, texture of the plutons, contact-metamorphic assemblage, and isotopic and fluid inclusion studies suggest that the plutons were emplaced at pressures of 1.5–3.0 kbars (5.2–10.5 km) into a part of the accretionary wedge with an ambient temperature of 210–300 °C. The presence of kyanite, garnet, and cordierite megacrysts in the plutons indicates that the melts were generated at a depth greater than 20 km and minimum temperature of 650 °C. These megacrysts are probably xenocrystic remnants of a restitic or contact metamorphic phase entrained by the melt during intrusion. However, it is also possible that they are primary magmatic phases crystallized from the peraluminous melt.Plutons of the Sanak-Baranof belt serve as time and strain markers separating kinematic regimes that predate and postdate ridge subduction. Pre-ridge subduction structures are interpreted to be related to the interaction between the leading oceanic plate and the Chugach terrane. These include regional thrust faults, NE-striking map-scale folds with associated axial planar foliation, type-1 mélanges, and an arrayof faults within the contact aureole indicating shortening largely accommodated by layer-parallel extension. Syn-ridge subduction features include the plutons, dikes, and ductile shear zones within contact aureoles with syn-kinematic metamorphic mineral growth and foliation development. Many of the studied plutons

SAMPLING-BASED APPROACH TO INVESTIGATING VAPOR INTRUSION

EPA Science Inventory

Vapor intrusion is defined as the migration of volatile organic compounds (VOCs) into occupied buildings from contaminated soil or ground water. EPA recently developed guidance to facilitate assessment of vapor intrusion at sites regulated by RCRA and CERCLA. The EPA guidance e...

Episodic intrusion, internal differentiation, and hydrothermal alteration of the miocene tatoosh intrusive suite south of Mount Rainier, Washington

USGS Publications Warehouse

du Bray, E.A.; Bacon, C.R.; John, D.A.; Wooden, J.L.; Mazdab, F.K.

2011-01-01

The Miocene Tatoosh intrusive suite south of Mount Rainier is composed of three broadly granodioritic plutons that are manifestations of ancestral Cascades arc magmatism. Tatoosh intrusive suite plutons have individually diagnostic characteristics, including texture, mineralogy, and geochemistry, and apparently lack internal contacts. New ion-microprobe U-Pb zircon ages indicate crystallization of the Stevens pluton ca. 19.2 Ma, Reflection-Pyramid pluton ca. 18.5 Ma, and Nisqually pluton ca. 17.5 Ma. The Stevens pluton includes rare, statistically distinct ca. 20.1 Ma zircon antecrysts. Wide-ranging zircon rare earth element (REE), Hf, U, and Th concentrations suggest late crystallization from variably evolved residual liquids. Zircon Eu/Eu*-Hf covariation is distinct for each of the Reflection-Pyramid, Nisqually, and Stevens plutons. Although most Tatoosh intrusive suite rocks have been affected by weak hydrothermal alteration, and sparse mineralized veins cut some of these rocks, significant base or precious metal mineralization is absent. At the time of shallow emplacement, each of these magma bodies was largely homogeneous in bulk composition and petrographic features, but, prior to final solidification, each of the Tatoosh intrusive suite plutons developed internal compositional variation. Geochemical and petrographic trends within each pluton are most consistent with differential loss of residual melt, possibly represented by late aplite dikes or erupted as rhyolite, from crystal-rich magma. Crystal-rich magma that formed each pluton evidently accumulated in reservoirs below the present level of exposure and then intruded to a shallow depth. Assembled by episodic intrusion, the Tatoosh intrusive suite may be representative of midsized composite plutonic complexes beneath arc volcanoes. ?? 2011 Geological Society of America.

Evidential reasoning research on intrusion detection

NASA Astrophysics Data System (ADS)

Wang, Xianpei; Xu, Hua; Zheng, Sheng; Cheng, Anyu

2003-09-01

In this paper, we mainly aim at D-S theory of evidence and the network intrusion detection these two fields. It discusses the method how to apply this probable reasoning as an AI technology to the Intrusion Detection System (IDS). This paper establishes the application model, describes the new mechanism of reasoning and decision-making and analyses how to implement the model based on the synscan activities detection on the network. The results suggest that if only rational probability values were assigned at the beginning, the engine can, according to the rules of evidence combination and hierarchical reasoning, compute the values of belief and finally inform the administrators of the qualities of the traced activities -- intrusions, normal activities or abnormal activities.

Saltwater intrusion in coastal regions of North America

USGS Publications Warehouse

Barlow, Paul M.; Reichard, Eric G.

2010-01-01

Saltwater has intruded into many of the coastal aquifers of the United States, Mexico, and Canada, but the extent of saltwater intrusion varies widely among localities and hydrogeologic settings. In many instances, the area contaminated by saltwater is limited to small parts of an aquifer and to specific wells and has had little or no effect on overall groundwater supplies; in other instances, saltwater contamination is of regional extent and has resulted in the closure of many groundwater supply wells. The variability of hydrogeologic settings, three-dimensional distribution of saline water, and history of groundwater withdrawals and freshwater drainage has resulted in a variety of modes of saltwater intrusion into coastal aquifers. These include lateral intrusion from the ocean; upward intrusion from deeper, more saline zones of a groundwater system; and downward intrusion from coastal waters. Saltwater contamination also has occurred along open boreholes and within abandoned, improperly constructed, or corroded wells that provide pathways for vertical migration across interconnected aquifers. Communities within the coastal regions of North America are taking actions to manage and prevent saltwater intrusion to ensure a sustainable source of groundwater for the future. These actions can be grouped broadly into scientific monitoring and assessment, engineering techniques, and regulatory approaches.

Imaging Saltwater Intrusion Along the Coast of Monterey Bay Using Long-Offset Electrical Resistivity Tomography

NASA Astrophysics Data System (ADS)

Goebel, M.; Knight, R. J.; Pidlisecky, A.

2016-12-01

Coastal regions represent a complex dynamic interface where saltwater intrusion moves seawater landward and groundwater discharge moves freshwater seaward. These processes can have a dramatic impact on water quality, affecting both humans and coastal ecosystems. The ability to map the subsurface distribution of fresh and salt water is a critical step in predicting and managing water quality in coastal regions. This is commonly accomplished using wells, which are expensive and provide point information, which may fail to capture the spatial complexity in subsurface conditions. We present an alternate method for acquiring data, long-offset Electrical Resistivity Tomography (ERT), which is non-invasive, cost effective, and can address the problem of poor spatial sampling. This geophysical method can produce continuous profiles of subsurface electrical resistivity to a depth of 300 m, with spatial resolution on the order of tens of meters. Our research focuses on the Monterey Bay region, where sustained groundwater extraction over the past century has led to significant saltwater intrusion. ERT was acquired along 40 kilometers of the coast using the roll along method, allowing for continuous overlap in data acquisition. Electrodes were spaced every 22.2 m, with a total of 81 electrodes along the 1.8 km active cable length. The data show a complex distribution of fresh and salt water, influenced by geology, groundwater pumping, recharge, and land-use. While the inverted ERT resistivity profiles correspond well with existing data sets and geologic interpretations in the region, the spatial complexity revealed through the ERT data goes beyond what is known from traditional data sources alone. This leads us to conclude that this form of data can be extremely useful in informing and calibrating groundwater flow models, making targeted management decisions, and monitoring changes in subsurface salinities over time.

Postemplacement dynamics of basaltic intrusions in the continental crust

NASA Astrophysics Data System (ADS)

Roman, A.; Jaupart, C.

2017-02-01

Laboratory experiments document the postemplacement behavior of mafic intrusions that spread at a density interface and founder as they become denser than their surroundings due to cooling and crystallization. All else being equal, the larger the intrusion volume, the farther the intrusion can spread and the smaller its aspect ratio is. The final aspect ratio is a function of a single dimensionless number analogous to the Rayleigh number of thermal convection. Once it is denser than its surroundings, the intrusion becomes unstable and may founder in two different regimes. At aspect ratios larger than about 0.4, the "teardrop" regime is such that the intrusion thickens in a central region, developing the shapes of a funnel and a pendant drop. At lower aspect ratios, another regime is observed, with thickening of the intrusion at the leading edge and thinning in a central region. The thick outer ring in turn becomes unstable into a set of teardrops and leads to an irregular horizontal outline. In one variant called the "jellyfish" regime, the thin central region develops a number of downwellings and upwellings in a Rayleigh-Taylor-like pattern. These instabilities may get arrested due to cooling as the intrusion and encasing rocks become too strong to deform. One would then be left with a funnel-shaped residual body or a wide irregular one with thick peripheral lobes and a thinner central region. These different patterns can be recognized in upper crustal mafic intrusions.

10 CFR 63.322 - Human intrusion scenario.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false Human intrusion scenario. 63.322 Section 63.322 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Postclosure Public Health and Environmental Standards Human Intrusion...

10 CFR 63.322 - Human intrusion scenario.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false Human intrusion scenario. 63.322 Section 63.322 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Postclosure Public Health and Environmental Standards Human Intrusion...

10 CFR 63.322 - Human intrusion scenario.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false Human intrusion scenario. 63.322 Section 63.322 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Postclosure Public Health and Environmental Standards Human Intrusion...

10 CFR 63.322 - Human intrusion scenario.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Human intrusion scenario. 63.322 Section 63.322 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Postclosure Public Health and Environmental Standards Human Intrusion...

Vapour Intrusion into Buildings - A Literature Review

EPA Science Inventory

This chapter provides a review of recent research on vapour intrusion of volatile organic compounds (VOCs) into buildings. The chapter builds on a report from Tillman and Weaver (2005) which reviewed the literature on vapour intrusion through 2005. Firstly, the term ‘vapour intru...

Modification of the fault logic circuit of a high-energy linear accelerator to accommodate selectively coded, large-field wedges.

PubMed

Miller, R W; van de Geijn, J

1987-01-01

A modification to the fault logic circuit that controls the collimator (COLL) fault is described. This modification permits the use of large-field wedges by adding an additional input into the reference voltage that determines the fault condition. The resistor controlling the amount of additional voltage is carried on board each wedge, within the wedge plug. This allows each wedge to determine its own, individual field size limit. Additionally, if no coding resistor is provided, the factory-supplied reference voltage is used, which sets the maximum allowable field size to 15 cm. This permits the use of factory-supplied wedges in conjunction with selected, large-field wedges, allowing proper sensing of the field size maximum in all conditions.

Perceived illness intrusions among continuous ambulatory peritoneal dialysis patients.

PubMed

Bapat, Usha; Kedlya, Prashanth G

2012-09-01

To study the perceived illness intrusion of continuous ambulatory peritoneal dialysis (CAPD) patients, to examine their demographics, and to find out the association among demographics, duration of illness as well as illness intrusion, 40 chronic kidney disease stage V patients on CAPD during 2006-2007 were studied. Inclusion criteria were patients' above 18 years, willing, stable, and completed at least two months of dialysis. Those with psychiatric co-morbidity were excluded. Sociodemographics were collected using a semi-structured interview schedule. A 14-item illness intrusion checklist covering various aspects of life was administered. The subjects had to rate the illness intrusion in their daily life and the extent of intrusion. The data was analyzed using descriptive statistics and chi square test of association. The mean age of the subjects was 56.05 ± 10.05 years. There was near equal distribution of gender. 82.5% were married, 70.0% belonged to Hindu religion, 45.0% were pre-degree, 25.0% were employed, 37.5% were housewives and 30.0% had retired. 77.5% belonged to the upper socioeconomic strata, 95.0% were from an urban background and 65.0% were from nuclear families. The mean duration of dialysis was 19.0 ± 16.49 months. Fifty-eight percent of the respondents were performing the dialysis exchanges by themselves. More than 95.0%were on three or four exchanges per day. All the 40 subjects reported illness intrusion in their daily life. Intrusion was perceived to some extent in the following areas: health 47.5%, work 25.0%, finance 37.5%, diet 40.0%, and psychological 50.0%. Illness had not intruded in the areas of relationship with spouse 52.5%, sexual life 30.0%, with friends 92.5%, with family 85.5%, social functions 52.5%, and religious functions 75.0%. Statistically significant association was not noted between illness intrusion and other variables. CAPD patients perceived illness intrusion to some extent in their daily life. Elderly, educated

Impingement of water droplets on wedges and diamond airfoils at supersonic speeds

NASA Technical Reports Server (NTRS)

Serafini, John S

1953-01-01

An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves. The results presented include the following conditions: droplet diameters from 2 to 100 microns, pressure altitudes from sea level to 30,000 feet, free-stream static temperatures from 420 degrees to 460 degrees R. Also, free-stream Mach numbers from 1.1 to 2.0, semi-apex angles for the wedge from 1.14 degrees to 7.97 degrees, thickness-to-chord ratios for the diamond airfoil from 0.02 to 0.14, chord lengths from 1 to 20 feet, and angles of attack from zero to the inverse tangent of the airfoil thickness-to-chord ratio.

The influence of wedge diffuser blade number and divergence angle on the performance of a high pressure ratio centrifugal compressor

NASA Astrophysics Data System (ADS)

Wang, Yi; Han, Ge; Lu, Xingen; Zhu, Junqiang

2018-02-01

Wedge diffuser is widely used in centrifugal compressors due to its high performance and compact size. This paper is aimed to research the influence of wedge diffuser blade number and divergence angle on centrifugal compressor performance. The impact of wedge diffuser blade number on compressor stage performance is investigated, and then the wedge diffusers with different divergence angle are studied by varying diffuser wedge angle and blade number simultaneously. It is found that wedge diffuser with 27 blades could have about 0.8% higher adiabatic efficiency and 0.14 higher total pressure ratio than the wedge diffuser with 19 blades and the best compressor performance is achieved when diffuser divergence angle is 8.3°.These results could give some advices on centrifugal compressor design.

Dispersion analysis and measurement of circular cylindrical wedge-like acoustic waveguides.

PubMed

Yu, Tai-Ho

2015-09-01

This study investigated the propagation of flexural waves along the outer edge of a circular cylindrical wedge, the phase velocities, and the corresponding mode displacements. Thus far, only approximate solutions have been derived because the corresponding boundary-value problems are complex. In this study, dispersion curves were determined using the bi-dimensional finite element method and derived through the separation of variables and the Hamilton principle. Modal displacement calculations clarified that the maximal deformations appeared at the outer edge of the wedge tip. Numerical examples indicated how distinct thin-film materials deposited on the outer surface of the circular cylindrical wedge influenced the dispersion curves. Additionally, dispersion curves were measured using a laser-induced guided wave, a knife-edge measurement scheme, and a two-dimensional fast Fourier transform method. Both the numerical and experimental results correlated closely, thus validating the numerical solution. Copyright © 2015 Elsevier B.V. All rights reserved.

Crossing the boundary: experimental investigation of water entry conditions of V-shaped wedges

NASA Astrophysics Data System (ADS)

Xiao, Tingben; Yohann, Daniel; Vincent, Lionel; Jung, Sunghwan; Kanso, Eva

2016-11-01

Seabirds that plunge-dive at high speeds exhibit remarkable abilities to withstand and mitigate impact forces. To minimize these forces, diving birds streamline their shape at impact, entering water with their sharp beak first. Here, we investigate the impact forces on rigid V-shaped wedges crossing the air-water interface at high Weber numbers. We vary the impact velocity V by adjusting the height from which the wedge is dropped. Both a high-speed camera and a force transducer are used to characterize the impact. We found that the splash base and air cavity show little dependence on the impact velocity when rescaling by inertial time d / V , where d is the breadth of the wedge. The peak impact force occurs at time tp smaller than the submersion time ts such that the ratio tp /ts is almost constant for all wedges and impact velocities V. We also found that the maximum impact force, like drag force, scales as AV2 , where A is the cross-sectional area of the wedge. We then propose analytical models of the impact force and splash dynamics. The theoretical predictions agree well with our experimental results. We conclude by commenting on the relevance of these results to understanding the mechanics of diving seabirds. We acknowledge support from the National Science Foundation.

A New Intrusion Detection Method Based on Antibody Concentration

NASA Astrophysics Data System (ADS)

Zeng, Jie; Li, Tao; Li, Guiyang; Li, Haibo

Antibody is one kind of protein that fights against the harmful antigen in human immune system. In modern medical examination, the health status of a human body can be diagnosed by detecting the intrusion intensity of a specific antigen and the concentration indicator of corresponding antibody from human body’s serum. In this paper, inspired by the principle of antigen-antibody reactions, we present a New Intrusion Detection Method Based on Antibody Concentration (NIDMBAC) to reduce false alarm rate without affecting detection rate. In our proposed method, the basic definitions of self, nonself, antigen and detector in the intrusion detection domain are given. Then, according to the antigen intrusion intensity, the change of antibody number is recorded from the process of clone proliferation for detectors based on the antigen classified recognition. Finally, building upon the above works, a probabilistic calculation method for the intrusion alarm production, which is based on the correlation between the antigen intrusion intensity and the antibody concen-tration, is proposed. Our theoretical analysis and experimental results show that our proposed method has a better performance than traditional methods.

A Survey on Anomaly Based Host Intrusion Detection System

NASA Astrophysics Data System (ADS)

Jose, Shijoe; Malathi, D.; Reddy, Bharath; Jayaseeli, Dorathi

2018-04-01

An intrusion detection system (IDS) is hardware, software or a combination of two, for monitoring network or system activities to detect malicious signs. In computer security, designing a robust intrusion detection system is one of the most fundamental and important problems. The primary function of system is detecting intrusion and gives alerts when user tries to intrusion on timely manner. In these techniques when IDS find out intrusion it will send alert massage to the system administrator. Anomaly detection is an important problem that has been researched within diverse research areas and application domains. This survey tries to provide a structured and comprehensive overview of the research on anomaly detection. From the existing anomaly detection techniques, each technique has relative strengths and weaknesses. The current state of the experiment practice in the field of anomaly-based intrusion detection is reviewed and survey recent studies in this. This survey provides a study of existing anomaly detection techniques, and how the techniques used in one area can be applied in another application domain.

Radiographic Outcomes Following Lateral Column Lengthening With a Porous Titanium Wedge.

PubMed

Gross, Christopher E; Huh, Jeannie; Gray, Joni; Demetracopoulos, Constantine; Nunley, James A

2015-08-01

Lateral column lengthening (LCL) is commonly utilized in treating stage II posterior tibialis tendon dysfunction. This study aimed to analyze the outcomes of LCL with porous titanium wedges compared to historic controls of iliac crest autograft and allograft. We hypothesized that the use of a porous titanium wedge would have radiographic improvement and union rates similar to those with the use of autograft and allograft in LCL. Between May 2009 and May 2014, 28 feet in 26 patients were treated with LCL using a porous titanium wedge. Of the 26 patients, 9 were males (34.6%). The average age for males was 43 years (range, 17.9-58.7), 48.7 years (range, 21-72.3) for females. Mean follow-up was 14.6 months. Radiographs were examined for correction of the flatfoot deformity and forefoot abduction. All complications were noted. Radiographically, the patients had a significant deformity correction in the anteroposterior talo-first metatarsal angle, talonavicular coverage angle, lateral talo-first metatarsal angle, and calcaneal pitch. All but 1 patient (96%) had bony incorporation of the porous titanium wedge. The average preoperative visual analog scale pain score was 5; all patients but 3 (12%) had improvements in their pain score, with a mean change of 3.4. LCL with porous titanium had low nonunion rates, improved radiographic correction, and pain relief. Level IV, case series. © The Author(s) 2015.

Stable isotope and gas properties of two ice wedges from Cape Mamontov Klyk, Laptev Sea, Northern Siberia

NASA Astrophysics Data System (ADS)

Boereboom, T.; Samyn, D.; Meyer, H.; Tison, J.-L.

2011-12-01

This paper presents and discusses the texture, fabric and gas properties (contents of total gas, O2, N2, CO2, and CH4) of two ice wedges from Cape Mamontov Klyk, Laptev Sea, Northern Siberia. The two ice wedges display contrasting structures: one being of relatively "clean" ice and the other showing clean ice at its centre as well as debris-rich ice on its sides (referred to as ice-sand wedge). A comparison of gas properties, crystal size, fabrics and stable isotope data (δ18O and δD) allows discriminating between three different facies of ice with specific paleoenvironmental signatures, suggesting different climatic conditions and rates of biological activity. More specifically, total gas content and composition reveal variable intensities of meltwater infiltration and show the impact of biological processes with contrasting contributions from anaerobic and aerobic conditions. Stable isotope data are shown to be valid for discussing changes in paleoenvironmental conditions and/or decipher different sources for the snow feeding into the ice wedges with time. Our data also give support to the previous assumption that the composite ice wedge was formed in Pleistocene and the ice wedge in Holocene times. This study sheds more light on the conditions of ice wedge growth under changing environmental conditions.

Successive reactive liquid flow episodes in a layered intrusion (Unit 9, Rum Eastern Layered Intrusion, Scotland)

NASA Astrophysics Data System (ADS)

Leuthold, Julien; Blundy, Jon; Holness, Marian

2014-05-01

We will present a detailed microstructural and geochemical study of reactive liquid flow in Unit 9 of the Rum Eastern Layered Intrusion. In the study region, Unit 9 comprises an underlying lens-like body of peridotite overlain by a sequence of troctolite and gabbro (termed allivalite), with some local and minor anorthosite. The troctolite is separated from the overlying gabbro by a distinct, sub-horizontal, undulose horizon (the major wavy horizon). Higher in the stratigraphy is another, similar, horizon (the minor wavy horizon) that separates relatively clinopyroxene-poor gabbro from an overlying gabbro. To the north of the peridotite lens, both troctolite and gabbro grade into poikilitic gabbro. Clinopyroxene habit in the allivalite varies from thin rims around olivine in troctolite, to equigranular crystals in gabbro, to oikocrysts in the poikilitic gabbro. The poikilitic gabbros contain multiple generations of clinopyroxene, with Cr-rich (~1.1 wt.% Cr2O3), anhedral cores with moderate REE concentrations (core1) overgrown by an anhedral REE-depleted second generation with moderate Cr (~0.7 wt.% Cr2O3) (core2). These composite cores are rimmed by Cr-poor (~0.2 wt.% Cr2O3) and REE-poor to moderate clinopyroxene. We interpret these microstructures as a consequence of two separate episodes of partial melting triggered by the intrusion of hot olivine-phyric picrite to form the discontinuous lenses that comprise the Unit 9 peridotite. Loss of clinopyroxene-saturated partial melt from the lower part of the allivalite immediately following the early stages of sill intrusion resulted in the formation of clinopyroxene-poor gabbro. The spatial extent of clinopyroxene loss is marked by the minor wavy horizon. A further partial melting event stripped out almost all clinopyroxene from the lowest allivalite, to form a troctolite, with the major wavy horizon marking the extent of melting during this second episode. The poikilitic gabbro formed from clinopyroxene-saturated melt

A new intrusion prevention model using planning knowledge graph

NASA Astrophysics Data System (ADS)

Cai, Zengyu; Feng, Yuan; Liu, Shuru; Gan, Yong

2013-03-01

Intelligent plan is a very important research in artificial intelligence, which has applied in network security. This paper proposes a new intrusion prevention model base on planning knowledge graph and discuses the system architecture and characteristics of this model. The Intrusion Prevention based on plan knowledge graph is completed by plan recognition based on planning knowledge graph, and the Intrusion response strategies and actions are completed by the hierarchical task network (HTN) planner in this paper. Intrusion prevention system has the advantages of intelligent planning, which has the advantage of the knowledge-sharing, the response focused, learning autonomy and protective ability.

Vapor Intrusion Assessment and Mitigation 2012

DTIC Science & Technology

2012-03-26

1 Geosyntec 0 consultants Vapor Intrusion Assessment and Mitigation 2012 Robert Ettinger, M.S., P.E., Todd McAiary, M.Sc., P.Eng., P.G...REPORT DATE 26 MAR 2012 2. REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Vapor Intrusion Assessment and...Updates • Typical Assessment Approaches and Common Challenges • Methods to Distinguish Background Sources (McHugh) • Significance • Compound

Study of salt transport processes in Delaware Bay

USGS Publications Warehouse

Walters, Roy

1992-01-01

The study described here is a subset of a broader climate-related study, and is focused primarily on salinity intrusion into Delaware Bay and River. Given changes in freshwater discharge into the Delaware River as determined from the larger study, and given probable sea level rise estimates, the purpose here is to calculate the distribution of salinity within Delaware Bay and River. The approach adopted for this study is composed of two parts: an analysis of existing physical data in order to derive a basic understanding of the salt dynamics, and numerical simulation of future conditions based on this analysis. There are two important constraints in the model used: it must resolve the spatial scales important to the salt dynamics, and it must be sufficiently efficient to allow extensive sensitivity studies. This has led to the development of a 3D model that uses harmonic decomposition in time and irregular finite elements in space. All nonlinear terms are retained in the governing equations, including quadratic bottom stress, advection, and wave transport (continuity nonlinearity). These equations are coupled to the advection-diffusion equation for salt so that density gradient forcing is included in the momentum equations. Although this study is still in progress, the model has reproduced sea level variations and the 3D structure of tidal and residual currents very well. In addition, the study has addressed the effects of a 1-meter rise in mean sea level on hydrodynamics of the study area. Current work is focused on salt dynamics.

Modeling the Evolution of Localized Strain in Orogenic Wedges: From Short-term Deformation to Long-term Tectonic States

NASA Astrophysics Data System (ADS)

Weiss, J. R.; Ito, G.; Brooks, B. A.; Olive, J. A. L.; Foster, J. H.; Howell, S. M.

2015-12-01

Some of the most destructive earthquakes on Earth are associated with active orogenic wedges. Despite a sound understanding of the basic mechanics that govern whole wedge structure over geologic time scales and a growing body of studies that have characterized the deformation associated with historic to recent earthquakes, first order questions remain about the linkage of the two sets of processes at the intermediate seismotectonic timescales. Numerical models have the power to test the effects of specific mechanical conditions on the evolution of observables at active orogenic wedges. Here we use a two-dimensional, continuum mechanics-based, finite difference method with a visco-elasto-plastic rheology coupled with surface processes to investigate the spatiotemporal distribution of deformation during wedge growth. The model simulates the contraction of a crustal layer overlying a weak base (décollement) against a rigid backstop and the spontaneous nucleation and evolution of fault zones due to cohesive, Mohr-Coulomb failure with strain weakening. Consistent with critical wedge theory, the average slope across the wedge is controlled by the relative frictional strengths of the wedge and décollement. Initial calculations predict changes in wedge deformation on short geologic timescales (103-105yrs) that involve episodes of widening as new, foreland-verging thrusts nucleate near the surface beyond the wedge toe and propagate down-dip to intersect the décollement. All the while, the wedge thickens via slip on older, internal fault zones. The aim of this study is to identify the parameters controlling the timescales of 1) episodic widening versus thickening and 2) nucleation and life-span of individual fault zones. These are initial steps needed to link earthquake observations to the long-term tectonic states inferred at various orogenic belts around the world.

Sojourner, Wedge, & Shark

NASA Technical Reports Server (NTRS)

1997-01-01

This Imager for Mars Pathfinder (IMP) image taken near the end of daytime operations on Sol 50 shows the Sojourner rover between the rocks 'Wedge' (foreground) and 'Shark' (behind rover). The rover successfully deployed its Alpha Proton X-Ray Spectrometer on Shark on Sol 52.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

A Preliminary Performance Assessment for Salt Disposal of High-Level Nuclear Waste - 12173

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

Lee, Joon H.; Clayton, Daniel; Jove-Colon, Carlos

2012-07-01

A salt repository is one of the four geologic media currently under study by the U.S. DOE Office of Nuclear Energy to support the development of a long-term strategy for geologic disposal of commercial used nuclear fuel (UNF) and high-level radioactive waste (HLW). The immediate goal of the generic salt repository study is to develop the necessary modeling tools to evaluate and improve the understanding of the repository system response and processes relevant to long-term disposal of UNF and HLW in a salt formation. The current phase of this study considers representative geologic settings and features adopted from previous studiesmore » for salt repository sites. For the reference scenario, the brine flow rates in the repository and underlying interbeds are very low, and transport of radionuclides in the transport pathways is dominated by diffusion and greatly retarded by sorption on the interbed filling materials. I-129 is the dominant annual dose contributor at the hypothetical accessible environment, but the calculated mean annual dose is negligibly small. For the human intrusion (or disturbed) scenario, the mean mass release rate and mean annual dose histories are very different from those for the reference scenario. Actinides including Pu-239, Pu-242 and Np-237 are major annual dose contributors, and the calculated peak mean annual dose is acceptably low. A performance assessment model for a generic salt repository has been developed incorporating, where applicable, representative geologic settings and features adopted from literature data for salt repository sites. The conceptual model and scenario for radionuclide release and transport from a salt repository were developed utilizing literature data. The salt GDS model was developed in a probabilistic analysis framework. The preliminary performance analysis for demonstration of model capability is for an isothermal condition at the ambient temperature for the near field. The capability demonstration

Numerical simulations of negative-index refraction in wedge-shaped metamaterials.

PubMed

Dong, Z G; Zhu, S N; Liu, H; Zhu, J; Cao, W

2005-07-01

A wedge-shaped structure made of split-ring resonators (SRR) and wires is numerically simulated to evaluate its refraction behavior. Four frequency bands, namely, the stop band, left-handed band, ultralow-index band, and positive-index band, are distinguished according to the refracted field distributions. Negative phase velocity inside the wedge is demonstrated in the left-handed band and the Snell's Law is conformed in terms of its refraction behaviors in different frequency bands. Our results confirmed that negative index of refraction indeed exists in such a composite metamaterial and also provided a convincing support to the results of previous Snell's Law experiments.

Integrated geophysical study of the Triassic salt bodies' geometry and evolution in central Tunisia

NASA Astrophysics Data System (ADS)

Azaiez, Hajer; Amri, Dorra Tanfous; Gabtni, Hakim; Bedir, Mourad; Soussi, Mohamed

2008-01-01

A comprehensive study, integrating gravity, magnetic and seismic reflection data, has been used to resolve the complex Triassic salt body geometry and evolution in central Tunisia. Regional seismic lines across the study area show a detachment level in the Upper Triassic evaporites, associated with chaotic seismic facies below the Souinia, Majoura, and Mezzouna structures. The Jurassic and Lower Cretaceous seismic horizons display pinching-outs and onlapping around these structures. A stack-velocity section confirms the existence of a high-velocity body beneath the Souinia Mountain. Regional gravity and magnetic profiles in this area were elaborated from ETAP (the Tunisian Firm of Petroleum Activities) measure stations. These profiles were plotted following the same layout from the west (Souinia) to the east (Mezzouna), across the Majoura and Kharrouba mountains. They highlight associated gravity and magnetic negative anomalies. These gravity and magnetic data coupled to the reflection seismic data demonstrate that, in the Souinia, Majoura, and El Hafey zones, the Triassic salt reaches a salt pillow and a salt-dome stage, without piercing the cover. These stages are expressed by moderately low gravity anomalies. On the other hand, in the Mezzouna area (part of the North-South Axis), the Triassic salt had pierced its cover during the Upper Cretaceous and the Tertiary, reaching a more advanced stage as a salt diapir and salt wall. These stages express important low gravity and magnetic anomalies. These results confirm the model of Tanfous et al. (2005) of halokinetic movements by fault intrusions inducing, from the west to the east, structures at different stages of salt pillow, salt dome, and salt diapir.

Noble gas systematics of the Skaergaard intrusion

NASA Astrophysics Data System (ADS)

Horton, F.; Farley, K. A.; Taylor, H. P.

2017-12-01

The noble gas isotopic compositions of olivines from the Skaergaard layered mafic intrusion in Greenland reveal that magmas readily exchange noble gases with their environment after emplacement. Although Skaergaard magmas are thought to have derived from the upper mantle, all of the olivine separates we analyzed have 3He/4He ratios less than that of the upper mantle ( 8 Ra, where Ra = 3He/4He of the atmosphere, 1.39 x 10-6). This suggests that crustal and/or atmospheric noble gases have contaminated all Skaergaard magmas to some extent. We obtained the highest 3He/4He ratios ( 2 Ra) from olivines found in the lowermost exposed layers of the intrusion away from the margins. Excess radiogenic 4He (indicated by Ra<1) along the margin of the intrusion indicates that noble gases from the Archean host-rock were incorporated into the cooling magma chamber, probably via magmatic assimilation. Noble gases in olivines from the upper portions of the intrusion have atmospheric isotopic compositions, but higher relative helium abundances than the atmosphere. We suggest that post-crystallization hydrothermal circulation introduced atmosphere-derived noble gases into uppermost layers of the intrusion. Such high temperature exchanges of volatiles between plutons and their immediate surroundings may help explain why so few mantle-derived rocks retain mantle-like noble gas signatures.

Subduction zone evolution and low viscosity wedges and channels

NASA Astrophysics Data System (ADS)

Manea, Vlad; Gurnis, Michael

2007-12-01

Dehydration of subducting lithosphere likely transports fluid into the mantle wedge where the viscosity is decreased. Such a decrease in viscosity could form a low viscosity wedge (LVW) or a low viscosity channel (LVC) on top of the subducting slab. Using numerical models, we investigate the influence of low viscosity wedges and channels on subduction zone structure. Slab dip changes substantially with the viscosity reduction within the LVWs and LVCs. For models with or without trench rollback, overthickening of slabs is greatly reduced by LVWs or LVCs. Two divergent evolutionary pathways have been found depending on the maximum depth extent of the LVW and wedge viscosity. Assuming a viscosity contrast of 0.1 with background asthenosphere, models with a LVW that extends down to 400 km depth show a steeply dipping slab, while models with an LVW that extends to much shallower depth, such as 200 km, can produce slabs that are flat lying beneath the overriding plate. There is a narrow range of mantle viscosities that produces flat slabs (5 to10 × 10 19 Pa s) and the slab flattening process is enhanced by trench rollback. Slab can be decoupled from the overriding plate with a LVC if the thickness is at least a few 10 s of km, the viscosity reduction is at least a factor of two and the depth extent of the LVC is several hundred km. These models have important implications for the geochemical and spatial evolution of volcanic arcs and the state of stress within the overriding plate. The models explain the poor correlation between traditional geodynamic controls, subducting plate age and convergence rates, on slab dip. We predict that when volcanic arcs change their distance from the trench, they could be preceded by changes in arc chemistry. We predict that there could be a larger volatile input into the wedge when arcs migrate toward the trench and visa-versa. The transition of a subduction zone into the flat-lying regime could be preceded by changes in the volatile

Cumulative effects of climate change and ice-wedge degradation, Prudhoe Bay oilfield Alaska

NASA Astrophysics Data System (ADS)

Walker, D. A.; Kanevskiy, M. Z.; Shur, Y.; Raynolds, M. K.; Buchhorn, M.

2016-12-01

Development of Arctic oil & gas resources requires extensive networks of roads, pipelines and other forms of infrastructure. The Prudhoe Bay Oilfield is the largest Arctic oilfield in North America with a long, well-documented history. In a previous publication we analyzed the historical record of high-resolution aerial photos to document the long-term changes to infrastructure extent (1949-2010) for the entire oilfield, and an integrated-geoecological-historical-change-mapping (IGHCM) approach to document terrain changes within 22-km2 areas of the oilfield. We reported the recent widespread expansion of thermokarst, starting in about 1989. Here we examine the annual air-photo record to better pinpoint the years of major change. We also conducted detailed field studies of roadside changes using topographic surveys and soil, vegetation and ice-wedge coring studies. Both sites exhibit extensive ice-wedge degradation that is caused by a combination of a long-term warming trend a series of exceptionally warm summers, and infrastructure-related factors that melted the tops of ice wedges. Near-road thermokarst is enhanced by warmer soils associated with road dust, roadside flooding, near-road pipelines, communication cables, and altered snow regimes. These strongly affect roadside ecosystems and the infrastructure itself. Changes to ecosystems include altered hydrology with the drying of polygon centers and the formation of well-developed high-centered polygons occurs in some areas. Other areas develop extensive flooding and erosion of ice-wedge troughs. An unexpected result of flooding is the stabilization of ice-wedge degradation in some areas because the increased productivity of sedges in the flooded areas is producing large amounts of organic material that protects the tops of ice wedges from further degradation. The large increases in productivity in roadside areas also attract large flocks of waterfowl. Changes to the soils with the addition of thick layers of

Cup-shaped Intrusions, Morphology and Emplacement Mechanism Investigate Through Analogue Modelling

NASA Astrophysics Data System (ADS)

Mathieu, L.; van Wyk de Vries, B.

2007-12-01

We investigate the morphology of large-scale shallow-depth magma intrusions and sub-volcanic complexes with analogue models. Intrusions of analogue magma are done in a granular material that can contain a ductile layer. The model surface is flat to model the formation of plutonic intrusions and it is overlain by a cone when modelling late sub-volcanic complexes. For flat-top models, we obtain cup-shaped intrusions fed by dykes. Cup-shaped intrusions are inverted-cone like bodies. They are different from saucer-shaped intrusions as they possess neither a well developed sill-base, nor an outer rim. However, like saucers, cups are shallow depth intrusions that dome the country rocks. They initiate from an advancing dyke and first develop an inverted-cone like morphology. Then, the central thickness increases and thrusts form at the edge of the domed country rocks. At this stage, the intrusions progressively involve toward a lopolith shape. By using analogue magma of various viscosities we have been able to constrain key relationships: higher intrusion viscosity causes deeper initiation and the deeper they initiate, the larger is the intrusion diameter. A natural example of such intrusion might by the circles of volcanoes like the Azufre-Lastaria (Peru) that might be overlain be a large-scale cup-shaped intrusion. When adding a cone at the surface of the model and, sometimes, a thin ductile layer in the substratum, the morphology of cup-shaped intrusions vary. Note that the ductile layer of our models is not thick enough to induce the gravitational spreading of the cone. Generally, cup-shaped intrusions are asymmetric in cross section and elliptical in plan view. Their formation creates extension structures in the cone (croissant-shaped rift, straight rift or normal fault) and thrusts in some sectors below the cone. Both types of structures are bordered by strike-slip faults. Cups and saucers share many similarities, but differ probably in the fact that saucers are

Climate adaptation wedges: a case study of premium wine in the western United States

NASA Astrophysics Data System (ADS)

Diffenbaugh, Noah S.; White, Michael A.; Jones, Gregory V.; Ashfaq, Moetasim

2011-04-01

Design and implementation of effective climate change adaptation activities requires quantitative assessment of the impacts that are likely to occur without adaptation, as well as the fraction of impact that can be avoided through each activity. Here we present a quantitative framework inspired by the greenhouse gas stabilization wedges of Pacala and Socolow. In our proposed framework, the damage avoided by each adaptation activity creates an 'adaptation wedge' relative to the loss that would occur without that adaptation activity. We use premium winegrape suitability in the western United States as an illustrative case study, focusing on the near-term period that covers the years 2000-39. We find that the projected warming over this period results in the loss of suitable winegrape area throughout much of California, including most counties in the high-value North Coast and Central Coast regions. However, in quantifying adaptation wedges for individual high-value counties, we find that a large adaptation wedge can be captured by increasing the severe heat tolerance, including elimination of the 50% loss projected by the end of the 2030-9 period in the North Coast region, and reduction of the projected loss in the Central Coast region from 30% to less than 15%. Increased severe heat tolerance can capture an even larger adaptation wedge in the Pacific Northwest, including conversion of a projected loss of more than 30% in the Columbia Valley region of Washington to a projected gain of more than 150%. We also find that warming projected over the near-term decades has the potential to alter the quality of winegrapes produced in the western US, and we discuss potential actions that could create adaptation wedges given these potential changes in quality. While the present effort represents an initial exploration of one aspect of one industry, the climate adaptation wedge framework could be used to quantitatively evaluate the opportunities and limits of climate adaptation

Climate adaptation wedges: a case study of premium wine in the western United States

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

Diffenbaugh, Noah; White, Michael A; Jones, Gregory V

2011-01-01

Design and implementation of effective climate change adaptation activities requires quantitative assessment of the impacts that are likely to occur without adaptation, as well as the fraction of impact that can be avoided through each activity. Here we present a quantitative framework inspired by the greenhouse gas stabilization wedges of Pacala and Socolow. In our proposed framework, the damage avoided by each adaptation activity creates an 'adaptation wedge' relative to the loss that would occur without that adaptation activity. We use premium winegrape suitability in the western United States as an illustrative case study, focusing on the near-term period thatmore » covers the years 2000 39. We find that the projected warming over this period results in the loss of suitable winegrape area throughout much of California, including most counties in the high-value North Coast and Central Coast regions. However, in quantifying adaptation wedges for individual high-value counties, we find that a large adaptation wedge can be captured by increasing the severe heat tolerance, including elimination of the 50% loss projected by the end of the 2030 9 period in the North Coast region, and reduction of the projected loss in the Central Coast region from 30% to less than 15%. Increased severe heat tolerance can capture an even larger adaptation wedge in the Pacific Northwest, including conversion of a projected loss of more than 30% in the Columbia Valley region of Washington to a projected gain of more than 150%. We also find that warming projected over the near-term decades has the potential to alter the quality of winegrapes produced in the western US, and we discuss potential actions that could create adaptation wedges given these potential changes in quality. While the present effort represents an initial exploration of one aspect of one industry, the climate adaptation wedge framework could be used to quantitatively evaluate the opportunities and limits of climate

Intrusive Memories in Perpetrators of Violent Crime: Emotions and Cognitions

ERIC Educational Resources Information Center

Evans, Ceri; Ehlers, Anke; Mezey, Gillian; Clark, David M.

2007-01-01

The authors investigated factors that may determine whether perpetrators of violent crime develop intrusive memories of their offense. Of 105 young offenders who were convicted of killing or seriously harming others, 46% reported distressing intrusive memories, and 6% had posttraumatic stress disorder. Intrusions were associated with lower…

Seismic signature of active intrusions in mountain chains.

PubMed

Di Luccio, Francesca; Chiodini, Giovanni; Caliro, Stefano; Cardellini, Carlo; Convertito, Vincenzo; Pino, Nicola Alessandro; Tolomei, Cristiano; Ventura, Guido

2018-01-01

Intrusions are a ubiquitous component of mountain chains and testify to the emplacement of magma at depth. Understanding the emplacement and growth mechanisms of intrusions, such as diapiric or dike-like ascent, is critical to constrain the evolution and structure of the crust. Petrological and geological data allow us to reconstruct magma pathways and long-term magma differentiation and assembly processes. However, our ability to detect and reconstruct the short-term dynamics related to active intrusive episodes in mountain chains is embryonic, lacking recognized geophysical signals. We analyze an anomalously deep seismic sequence (maximum magnitude 5) characterized by low-frequency bursts of earthquakes that occurred in 2013 in the Apennine chain in Italy. We provide seismic evidences of fluid involvement in the earthquake nucleation process and identify a thermal anomaly in aquifers where CO 2 of magmatic origin dissolves. We show that the intrusion of dike-like bodies in mountain chains may trigger earthquakes with magnitudes that may be relevant to seismic hazard assessment. These findings provide a new perspective on the emplacement mechanisms of intrusive bodies and the interpretation of the seismicity in mountain chains.

Seismic signature of active intrusions in mountain chains

PubMed Central

Di Luccio, Francesca; Chiodini, Giovanni; Caliro, Stefano; Cardellini, Carlo; Convertito, Vincenzo; Pino, Nicola Alessandro; Tolomei, Cristiano; Ventura, Guido

2018-01-01

Intrusions are a ubiquitous component of mountain chains and testify to the emplacement of magma at depth. Understanding the emplacement and growth mechanisms of intrusions, such as diapiric or dike-like ascent, is critical to constrain the evolution and structure of the crust. Petrological and geological data allow us to reconstruct magma pathways and long-term magma differentiation and assembly processes. However, our ability to detect and reconstruct the short-term dynamics related to active intrusive episodes in mountain chains is embryonic, lacking recognized geophysical signals. We analyze an anomalously deep seismic sequence (maximum magnitude 5) characterized by low-frequency bursts of earthquakes that occurred in 2013 in the Apennine chain in Italy. We provide seismic evidences of fluid involvement in the earthquake nucleation process and identify a thermal anomaly in aquifers where CO2 of magmatic origin dissolves. We show that the intrusion of dike-like bodies in mountain chains may trigger earthquakes with magnitudes that may be relevant to seismic hazard assessment. These findings provide a new perspective on the emplacement mechanisms of intrusive bodies and the interpretation of the seismicity in mountain chains. PMID:29326978

Effect of Laterally Wedged Insoles on the External Knee Adduction Moment across Different Reference Frames.

PubMed

Yamaguchi, Satoshi; Kitamura, Masako; Ushikubo, Tomohiro; Murata, Atsushi; Akagi, Ryuichiro; Sasho, Takahisa

2015-01-01

Biomechanical effects of laterally wedged insoles are assessed by reduction in the knee adduction moment. However, the degree of reduction may vary depending on the reference frame with which it is calculated. The purpose of this study was to clarify the effect of reference frame on the reduction in the knee adduction moment by laterally wedged insoles. Twenty-nine healthy participants performed gait trials with a laterally wedged insole and with a flat insole as a control. The knee adduction moment, including the first and second peaks and the angular impulse, were calculated using four different reference frames: the femoral frame, tibial frame, laboratory frame and the Joint Coordinate System. There were significant effects of reference frame on the knee adduction moment first and second peaks (P < 0.001 for both variables), while the effect was not significant for the angular impulse (P = 0.84). No significant interaction between the gait condition and reference frame was found in either of the knee adduction moment variables (P = 0.99 for all variables), indicating that the effects of laterally wedged insole on the knee adduction moments were similar across the four reference frames. On the other hand, the average percent changes ranged from 9% to 16% for the first peak, from 16% to 18% for the second peak and from 17% to 21% for the angular impulse when using the different reference frames. The effects of laterally wedged insole on the reduction in the knee adduction moment were similar across the reference frames. On the other hand, Researchers need to recognize that when the percent change was used as the parameter of the efficacy of laterally wedged insole, the choice of reference frame may influence the interpretation of how laterally wedged insoles affect the knee adduction moment.

Assessment of Neutron Contamination Originating from the Presence of Wedge and Block in Photon Beam Radiotherapy.

PubMed

Bahreyni Toossi, M T; Khajetash, B; Ghorbani, M

2018-03-01

One of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment. Objective: In the present study the impact of wedge and block on neutron contamination production is investigated. The evaluations are conducted for a 15 MV Siemens Primus linear accelerator. Simulations were performed using MCNPX Monte Carlo code. 30˚, 45˚ and 60˚ wedges and a cerrobend block with dimensions of 1.5 × 1.5 × 7 cm 3 were simulated. The investigation were performed in the 10 × 10 cm 2 field size at source to surface distance of 100 cm for depth of 0.5, 2, 3 and 4 cm in a water phantom. Neutron dose was calculated using F4 tally with flux to dose conversion factors and F6 tally. Results showed that the presence of wedge increases the neutron contamination when the wedge factor was considered. In addition, 45˚ wedge produced the most amount of neutron contamination. If the block is in the center of the field, the cerrobend block caused less neutron contamination than the open field due to absorption of neutrons and photon attenuation. The results showed that neutron contamination is less in steeper depths. The results for two tallies showed practically equivalent results. Wedge causes neutron contamination hence should be considered in therapeutic protocols in which wedge is used. In terms of clinical aspects, the results of this study show that superficial tissues such as skin will tolerate more neutron contamination than the deep tissues.

Effects of Lateral and Medial Wedged Insoles on Knee and Ankle Internal Joint Moments During Walking in Healthy Men.

PubMed

Fukuchi, Claudiane A; Lewinson, Ryan T; Worobets, Jay T; Stefanyshyn, Darren J

2016-11-01

Wedged insoles have been used to treat knee pathologies and to prevent injuries. Although they have received much attention for the study of knee injury, the effects of wedges on ankle joint biomechanics are not well understood. This study sought to evaluate the immediate effects of lateral and medial wedges on knee and ankle internal joint loading and center of pressure (CoP) in men during walking. Twenty-one healthy men walked at 1.4 m/sec in five footwear conditions: neutral, 6° (LW6) and 9° (LW9) lateral wedges, and 6° (MW6) and 9° (MW9) medial wedges. Peak internal knee abduction moments and angular impulses, internal ankle inversion moments and angular impulses, and mediolateral CoP were analyzed. Analysis of variance with post hoc analysis and Pearson correlations were performed to detect differences between conditions. No differences in internal knee joint loading were found between neutral and any of the wedge conditions. However, as the wedge angle increased from medial to lateral, the internal ankle inversion moment (LW6: P = .020; LW9: P < .001; MW6: P = .046; MW9: P < .001) and angular impulse (LW9: P = .012) increased, and the CoP shifted laterally (LW9: P < .001) and medially (MW9: P < .001) compared with the neutral condition. Neither lateral nor medial wedges were effective in altering internal knee joint loading during walking. However, the greater internal ankle inversion moment and angular impulse observed with lateral wedges could lead to a higher risk of ankle injury. Thus, caution should be taken when lateral wedges need to be prescribed.

Heart rate, startle response, and intrusive trauma memories

PubMed Central

Chou, Chia-Ying; Marca, Roberto La; Steptoe, Andrew; Brewin, Chris R

2014-01-01

The current study adopted the trauma film paradigm to examine potential moderators affecting heart rate (HR) as an indicator of peritraumatic psychological states and as a predictor of intrusive memories. We replicated previous findings that perifilm HR decreases predicted the development of intrusive images and further showed this effect to be specific to images rather than thoughts, and to detail rather than gist recognition memory. Moreover, a group of individuals showing both an atypical sudden reduction in HR after a startle stimulus and higher trait dissociation was identified. Only among these individuals was lower perifilm HR found to indicate higher state dissociation, fear, and anxiety, along with reduced vividness of intrusions. The current findings emphasize how peritraumatic physiological responses relate to emotional reactions and intrusive memory. The moderating role of individual difference in stress defense style was highlighted. PMID:24397333

Intrusion errors in visuospatial working memory performance.

PubMed

Cornoldi, Cesare; Mammarella, Nicola

2006-02-01

This study tested the hypothesis that failure in active visuospatial working memory tasks involves a difficulty in avoiding intrusions due to information that is already activated. Two experiments are described, in which participants were required to process several series of locations on a 4 x 4 matrix and then to produce only the final location of each series. Results revealed a higher number of errors due to already activated locations (intrusions) compared with errors due to new locations (inventions). Moreover, when participants were required to pay extra attention to some irrelevant (non-final) locations by tapping on the table, intrusion errors increased. Results are discussed in terms of current models of working memory functioning.

Porting Extremely Lightweight Intrusion Detection (ELIDe) to Android

DTIC Science & Technology

2015-10-01

ARL-TN-0681 ● OCT 2015 US Army Research Laboratory Porting Extremely Lightweight Intrusion Detection (ELIDe) to Android by...Lightweight Intrusion Detection (ELIDe) to Android by Ken F Yu and Garret S Payer Computational and Information Sciences Directorate, ARL...

Porous Flow and Diffusion of Water in the Mantle Wedge: Melting and Hydration Patterns

NASA Astrophysics Data System (ADS)

Conder, J. A.

2005-12-01

It is widely accepted that melting at volcanic arcs is primarily triggered by fluxing the mantle wedge from the dehydrating subducting slab. However, there is less concensus regarding how water moves into and within the mantle wedge. There are at least four possible mechanisms for water migration in the wedge: buoyant porous flow, diffusion through mineral crystals, advection of hydrated minerals, and compositionally buoyant diapers. The latter two mechanisms require at least one of the first two to occur to get water from the slab into the wedge before they can function. Using geodynamic models of mantle flow in a simplified subduction setting, we explore the implications of diffusion and porous flow of water in the wedge, particularly as they would affect the time for recycling water through the subduction factory and the predicted pattern of basalt hydration across the arc. The slab is assumed to dehydrate in a continuous fashion as the solubility of water in subducted oceanic crust decreases with temperature and pressure and the water then enters the wedge via one of the two transport mechanisms. Diffusion is controlled by temperature and by which minerals are present. Although olivine dominates the mantle mineral fraction, pyroxenes may control the diffusion of water in the wedge as the diffusivity of pyroxene is one or more orders of magnitude greater than olivine. Even assuming the faster diffusion rate of orthopyroxene in the models, diffusion can only be an important transport mechanism when subduction rates are slower than ~3 cm/yr. Flux melting occurs in the wedge above where the slab is ~100-160 km deep with the maximum above where the slab is ~120 km deep. Models including porous flow can result in melting at higher subduction rates provided the permeability of the mantle is greater than 10-17 m2. The true magnitude of the permeability likely varies with the corresponding porosity created by the free phase. With porous flow, melting occurs 20-30 km

How does layered heterogeneity affect the ability of subsurface dams to clean up coastal aquifers contaminated with seawater intrusion?

NASA Astrophysics Data System (ADS)

Abdoulhalik, Antoifi; Ahmed, Ashraf A.

2017-10-01

The main purpose of this work was to examine how aquifer layering impacts the ability of subsurface dams to retain seawater intrusion (SWI) and to clean up contaminated coastal aquifers using both experimental and numerical techniques. Four different layering configurations were investigated, including a homogeneous case (case H), and three different layered cases where a low permeability layer was set at the top of the aquifer (case LH), at the middle part of the aquifer as interlayer (case HLH), and at the lower part of the aquifer (case HL). The subsurface dam was able to retain the saltwater wedge associated with a drop of the hydraulic gradient from 0.0158 down to 0.0095 in all the cases, thereby achieving up to 78% reduction in the saltwater toe length. In cases LH and HLH, the start of the saltwater spillage was delayed compared to the homogeneous case, and the time taken for the freshwater zone to be fully contaminated (post-spillage) was twice and three times longer, respectively. By contrast, the existence of a low K layer at the bottom of the aquifer (case HL) considerably weakened the ability of dams to retain the intrusion, allowing for quicker saltwater spillage past the wall. The natural cleanup of SWI-contaminated coastal aquifers was, for the first time, evidenced in heterogeneous settings. Depending on the stratification pattern, the presence of stratified layers however prolonged the cleanup time to various degrees, compared to the homogeneous scenario, particularly in case HL, where the cleanup time was nearly 50% longer.

The appraisal of intrusive thoughts in relation to obsessional-compulsive symptoms.

PubMed

Barrera, Terri L; Norton, Peter J

2011-01-01

Research has shown that although intrusive thoughts occur universally, the majority of individuals do not view intrusive thoughts as being problematic (Freeston, Ladouceur, Thibodeau, & Gagnon, 1991; Rachman & de Silva, 1978; Salkovskis & Harrison, 1984). Thus, it is not the presence of intrusive thoughts that leads to obsessional problems but rather some other factor that plays a role in the development of abnormal obsessions. According to the cognitive model of obsessive-compulsive disorder (OCD) put forth by Salkovskis (1985), the crucial factor that differentiates between individuals with OCD and those without is the individual's appraisal of the naturally occurring intrusive thoughts. This study aimed to test Salkovskis's model by examining the role of cognitive biases (responsibility, thought-action fusion, and thought control) as well as distress in the relationship between intrusive thoughts and obsessive-compulsive symptoms in an undergraduate sample of 326 students. An existing measure of intrusive thoughts (the Revised Obsessional Intrusions Inventory) was modified for this study to include a scale of distress associated with each intrusive thought in addition to the current frequency scale. When the Yale-Brown Obsessive-Compulsive Scale was used as the measure of OCD symptoms, a significant interaction effect of frequency and distress of intrusive thoughts resulted. Additionally, a significant three-way interaction of Frequency × Distress × Responsibility was found when the Obsessive Compulsive Inventory-Revised was used as the measure of OCD symptoms. These results indicate that the appraisal of intrusive thoughts is important in predicting OCD symptoms, thus providing support for Salkovskis's model of OCD.

Wedge filter imaging spectrometer

NASA Astrophysics Data System (ADS)

Sémery, Alain; Réess, Jean-Michel; Lemarquis, Frédéric; Drossart, Pierre; Laubier, David; Bernardi, Pernelle

2017-11-01

The development of the planetary exploration for landers makes it more and more necessary to have at our disposal small and light instruments. This is why we are developing in our laboratory a light imaging spectrometer with a wedge filter making the spectral splitting. This design already developed in other laboratories has the great advantage to need a limited number of optical components. However its drawback is that at a given instant the different spectral pixels don't see the same spot in the field. We propose a new design to remedy this drawback by the adjunction of a dispersive system in the fore-optics.

Evaluation of Hanford Single-Shell Waste Tanks Suspected of Water Intrusion

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

Feero, Amie J.; Washenfelder, Dennis J.; Johnson, Jeremy M.

2013-11-14

Intrusions evaluations for twelve single-shell tanks were completed in 2013. The evaluations consisted of remote visual inspections, data analysis, and calculations of estimated intrusion rates. The observation of an intrusion or the preponderance of evidence confirmed that six of the twelve tanks evaluated had intrusions. These tanks were tanks 241-A-103, BX-101, BX-103, BX-110, BY-102, and SX-106.

Saharan dust intrusions in Spain: Health impacts and associated synoptic conditions.

PubMed

Díaz, Julio; Linares, Cristina; Carmona, Rocío; Russo, Ana; Ortiz, Cristina; Salvador, Pedro; Trigo, Ricardo Machado

2017-07-01

A lot of papers have been published about the impact on mortality of Sahara dust intrusions in individual cities. However, there is a lack of studies that analyse the impact on a country and scarcer if in addition the analysis takes into account the meteorological conditions that favour these intrusions. The main aim is to examine the effect of Saharan dust intrusions on daily mortality in different Spanish regions and to characterize the large-scale atmospheric circulation anomalies associated with such dust intrusions. For determination of days with Saharan dust intrusions, we used information supplied by the Ministry of Agriculture, Food & Environment, it divides Spain into 9 main areas. In each of these regions, a representative province was selected. A time series analysis has been performed to analyse the relationship between daily mortality and PM 10 levels in the period from 01.01.04 to 31.12.09, using Poisson regression and stratifying the analysis by the presence or absence of Saharan dust advections. The proportion of days on which there are Saharan dust intrusions rises to 30% of days. The synoptic pattern is characterised by an anticyclonic ridge extending from northern Africa to the Iberian Peninsula. Particulate matter (PM) on days with intrusions are associated with daily mortality, something that does not occur on days without intrusions, indicating that Saharan dust may be a risk factor for daily mortality. In other cases, what Saharan dust intrusions do is to change the PM-related mortality behaviour pattern, going from PM 2.5 . A study such as the one conducted here, in which meteorological analysis of synoptic situations which favour Saharan dust intrusions, is combined with the effect on health at a city level, would seem to be crucial when it comes to analysing the differentiated mortality pattern in situations of Saharan dust intrusions. Copyright © 2017 Elsevier Inc. All rights reserved.

Experimental and numerical investigations on melamine wedges.

PubMed

Schneider, S

2008-09-01

Melamine wedges are often used as acoustic lining material for anechoic chambers. It was proposed here to study the effects of the mounting conditions on the acoustic properties of the melamine wedges used in the large anechoic chamber at the LMA. The results of the impedance tube measurements carried out show that the mounting conditions must be taken into account when assessing the quality of an acoustic lining. As it can be difficult to simulate these mounting conditions in impedance tube experiments, a numerical method was developed, which can be used to complete the experiments or for parametric studies. By combining the finite and the boundary element method, it is possible to investigate acoustic linings with almost no restrictions as to the geometry, material behavior, or mounting conditions. The numerical method presented here was used to study the acoustic properties of the acoustic lining installed in the anechoic chamber at the LMA. Further experiments showed that the behavior of the melamine foam is anisotropic. Numerical simulations showed that this anisotropy can be used to advantage when designing an acoustic lining.

Hydrogeologic conditions and saline-water intrusion, Cape Coral, Florida, 1978-81

USGS Publications Warehouse

Fitzpatrick, D.J.

1986-01-01

The upper limestone unit of the intermediate aquifer system, locally called the upper Hawthorn aquifer, is the principal source of freshwater for Cape Coral, Florida. The aquifer has been contaminated with saline water by downward intrusion from the surficial aquifer system and by upward intrusion from the Floridan aquifer system. Much of the intrusion has occurred through open wellbores where steel casings are short or where casings have collapsed because of corrosion. Saline-water contamination of the upper limestone unit due to downward intrusion from the surficial aquifer is most severe in the southern and eastern parts of Cape Coral; contamination due to upward intrusion has occurred in many areas throughout Cape Coral. Intrusion is amplified in areas of heavy water withdrawals and large water-level declines. (USGS)

Integrated waste management as a climate change stabilization wedge.

PubMed

Bahor, Brian; Van Brunt, Michael; Stovall, Jeff; Blue, Katherine

2009-11-01

Anthropogenic sources of greenhouse gas emissions are known to contribute to global increases in greenhouse gas concentrations and are widely believed to contribute to climate change. A reference carbon dioxide concentration of 383 ppm for 2007 is projected to increase to a nominal 500 ppm in less than 50 years according to business as usual models. This concentration change is equivalent to an increase of 7 billion tonnes of carbon per year (7 Gt C year(-1)). The concept of a stabilization wedge was introduced by Pacala and Socolow (Science, 305, 968-972, 2004) to break the 7 Gt C year(- 1) into more manageable 1 Gt C year(- 1) reductions that would be achievable with current technology. A total of fifteen possible 'wedges' were identified; however, an integrated municipal solid waste (MSW) management system based on the European Union's waste management hierarchy was not evaluated as a wedge. This analysis demonstrates that if the tonnage of MSW is allocated to recycling, waste to energy and landfilling in descending order in lieu of existing 'business-as-usual' practices with each option using modern technology and best practices, the system would reduce greenhouse gas emissions by more than 1 Gt C year( -1). This integrated waste management system reduces CO(2) by displacing fossil electrical generation and avoiding manufacturing energy consumption and methane emissions from landfills.

Wedge Shock and Nozzle Exhaust Plume Interaction in a Supersonic Jet Flow

NASA Technical Reports Server (NTRS)

Castner, Raymond; Zaman, Khairul; Fagan, Amy; Heath, Christopher

2014-01-01

Fundamental research for sonic boom reduction is needed to quantify the interaction of shock waves generated from the aircraft wing or tail surfaces with the nozzle exhaust plume. Aft body shock waves that interact with the exhaust plume contribute to the near-field pressure signature of a vehicle. The plume and shock interaction was studied using computational fluid dynamics and compared with experimental data from a coaxial convergent-divergent nozzle flow in an open jet facility. A simple diamond-shaped wedge was used to generate the shock in the outer flow to study its impact on the inner jet flow. Results show that the compression from the wedge deflects the nozzle plume and shocks form on the opposite plume boundary. The sonic boom pressure signature of the nozzle exhaust plume was modified by the presence of the wedge. Both the experimental results and computational predictions show changes in plume deflection.

Redistribution of knee stress using laterally wedged insole intervention: Finite element analysis of knee-ankle-foot complex.

PubMed

Liu, Xuan; Zhang, Ming

2013-01-01

Laterally wedged insoles are widely applied in the conservative treatment for medial knee osteoarthritis. Experimental studies have been conducted to understand the effectiveness of such an orthotic intervention. However, the information was limited to the joint external loading such as knee adduction moment. The internal stress distribution is difficult to be obtained from in vivo experiment alone. Thus, a three-dimensional finite element model of the human knee-ankle-foot complex, together with orthosis, was developed in this study and used to investigate the redistribution of knee stress using laterally wedged insole intervention. Laterally wedged insoles with wedge angles of 0, 5, and 10° were fabricated for intervention. The subject-specific geometry of the lower extremity with details was characterized in the reconstruction of MR images. Motion analysis data and muscle forces were input to drive the model. The established finite element model was employed to investigate the loading responses of tibiofemoral articulation in three wedge angle conditions during simulated walking stance phase. With either of the 5° or 10° laterally wedged insole, significant decreases in von Mises stress and contact force at the medial femur cartilage region and the medial meniscus were predicted comparing with the 0° insole. The diminished stress and contact force at the medial compartment of the knee joint demonstrate the immediate effect of the laterally wedged insoles. The intervention may contribute to medial knee osteoarthritis rehabilitation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mantle wedge exhumation beneath the Dora-Maira (U)HP dome unravelled by local earthquake tomography (Western Alps)

NASA Astrophysics Data System (ADS)

Solarino, Stefano; Malusà, Marco G.; Eva, Elena; Guillot, Stéphane; Paul, Anne; Schwartz, Stéphane; Zhao, Liang; Aubert, Coralie; Dumont, Thierry; Pondrelli, Silvia; Salimbeni, Simone; Wang, Qingchen; Xu, Xiaobing; Zheng, Tianyu; Zhu, Rixiang

2018-01-01

In continental subduction zones, the behaviour of the mantle wedge during exhumation of (ultra)high-pressure [(U)HP] rocks provides a key to distinguish among competing exhumation mechanisms. However, in spite of the relevant implications for understanding orogenic evolution, a high-resolution image of the mantle wedge beneath the Western Alps is still lacking. In order to fill this gap, we perform a detailed analysis of the velocity structure of the Alpine belt beneath the Dora-Maira (U)HP dome, based on local earthquake tomography independently validated by receiver function analysis. Our results point to a composite structure of the mantle wedge above the subducted European lithosphere. We found that the Dora-Maira (U)HP dome lays directly above partly serpentinized peridotites (Vp 7.5 km/s; Vp/Vs = 1.70-1.72), documented from 10 km depth down to the top of the eclogitized lower crust of the European plate. These serpentinized peridotites, possibly formed by fluid release from the subducting European slab to the Alpine mantle wedge, are juxtaposed against dry mantle peridotites of the Adriatic upper plate along an active fault rooted in the lithospheric mantle. We propose that serpentinized mantle-wedge peridotites were exhumed at shallow crustal levels during late Eocene transtensional tectonics, also triggering the rapid exhumation of (U)HP rocks, and were subsequently indented under the Alpine metamorphic wedge in the early Oligocene. Our findings suggest that mantle-wedge exhumation may represent a major feature of the deep structure of exhumed continental subduction zones. The deep orogenic levels here imaged by seismic tomography may be exposed today in older (U)HP belts, where mantle-wedge serpentinites are commonly associated with coesite-bearing continental metamorphic rocks.

Stuck in the spin cycle: Avoidance and intrusions following breast cancer diagnosis.

PubMed

Bauer, Margaret R; Wiley, Joshua F; Weihs, Karen L; Stanton, Annette L

2017-09-01

Theories and research regarding cognitive and emotional processing during the experience of profound stressors suggest that the presence of intrusive thoughts and feelings predicts greater use of avoidance and that the use of avoidance paradoxically predicts more intrusions. However, empirical investigations of their purported bidirectional relationship are limited. This study presents a longitudinal investigation of the reciprocal relationship between intrusions and avoidance coping over a 6-month period in the year following breast cancer diagnosis. Breast cancer patients (N = 460) completed measures of cancer-related intrusions and avoidance at study entry, 3 months, and 6 months later (i.e., an average of 2, 5, and 8 months after diagnosis, respectively). Cross-lagged panel analyses revealed that intrusive thoughts, feelings, and images at study entry predicted greater avoidance 3 months later, and avoidance coping at study entry predicted intrusions 3 months later, controlling for the stability of intrusions and avoidance as well as time since diagnosis. Findings were not statistically significant for avoidance predicting intrusions, or vice versa, between the 3-month and the 6-month assessment period, during which they declined. These findings provide empirical support for the theoretical contention that avoidance and intrusive thoughts and emotions reciprocally influence one another following stressful events. Additionally, in the months shortly after breast cancer diagnosis, intrusions and avoidance are positively related. However, the relationships attenuate over time, which could indicate resolved cognitive and emotional processing of the cancer experience. Statement of contribution What is already known on this subject? Following stressful life events, individuals often experience intrusive thoughts and feelings related to the event and they report avoidance of such reminders. Many studies demonstrate that greater intrusions predict more

Computer Intrusions and Attacks.

ERIC Educational Resources Information Center

Falk, Howard

1999-01-01

Examines some frequently encountered unsolicited computer intrusions, including computer viruses, worms, Java applications, trojan horses or vandals, e-mail spamming, hoaxes, and cookies. Also discusses virus-protection software, both for networks and for individual users. (LRW)

Opportunities and Barriers to Address Seawater Intrusion Along California's Coast

NASA Astrophysics Data System (ADS)

Langridge, R.

2016-12-01

In many California coastal areas reliant on groundwater seawater intrusion is a serious problem. This presentation will discuss how particular groundwater management institutions in the state are addressing seawater intrusion issues, how stakeholders are participating in this process, and how scientific information can contribute to policies that support reducing or halting ongoing intrusion. In 2014, the California Legislature passed the Sustainable Groundwater Management Act (SGMA). The Act established requirements for 127 high and medium priority groundwater basins to form groundwater sustainability agencies (GSAs) and develop plans to sustainably manage their basin. Sustainable is defined in SGMA as avoiding specific unacceptable impacts, including significant and unreasonable seawater intrusion. Special Act Districts, created by an act of the legislature, have the option to be the sole GSA in their service area, and they can provide a window into current and potentially future strategies to address seawater intrusion. Additionally, adjudicated basins are often considered one of the best approaches to achieve efficient groundwater management, and these basins are exempt from SGMA and managed pursuant to a court judgment. The strategies utilized to manage seawater intrusion by three special act districts and five adjudicated basins will be discussed. These basins cover significant areas of central and southern California and all have experienced seawater intrusion. Our research team just completed reports for the State Water Resources Control Board on all the adjudicated and special act districts in the state, and this presentation will draw on our findings to better understand the barriers and opportunities to alleviate seawater intrusion and the information required to develop solutions.

Intrusion of Magmatic Bodies Into the Continental Crust: 3-D Numerical Models

NASA Astrophysics Data System (ADS)

Gorczyk, Weronika; Vogt, Katharina

2018-03-01

Magma intrusion is a major material transfer process in the Earth's continental crust. Yet the mechanical behavior of the intruding magma and its host are a matter of debate. In this study we present a series of numerical thermomechanical simulations on magma emplacement in 3-D. Our results demonstrate the response of the continental crust to magma intrusion. We observe change in intrusion geometries between dikes, cone sheets, sills, plutons, ponds, funnels, finger-shaped and stock-like intrusions, and injection time. The rheology and temperature of the host are the main controlling factors in the transition between these different modes of intrusion. Viscous deformation in the warm and deep crust favors host rock displacement and plutons at the crust-mantle boundary forming deep-seated plutons or magma ponds in the lower to middle crust. Brittle deformation in the cool and shallow crust induces cone-shaped fractures in the host rock and enables emplacement of finger- or stock-like intrusions at shallow or intermediate depth. Here the passage of magmatic and hydrothermal fluids from the intrusion through the fracture pattern may result in the formation of ore deposits. A combination of viscous and brittle deformation forms funnel-shaped intrusions in the middle crust. Intrusion of low-density magma may more over result in T-shaped intrusions in cross section with magma sheets at the surface.

Thermal regime of an ice-wedge polygon landscape near Barrow, Alaska

NASA Astrophysics Data System (ADS)

Daanen, R. P.; Liljedahl, A. K.

2017-12-01

Tundra landscapes are changing all over the circumpolar Arctic due to permafrost degradation. Soil cracking and infilling of meltwater repeated over thousands of years form ice wedges, which produce the characteristic surface pattern of ice-wedge polygon tundra. Rapid top-down thawing of massive ice leads to differential ground subsidence and sets in motion a series of short- and long-term hydrological and ecological changes. Subsequent responses in the soil thermal regime drive further permafrost degradation and/or stabilization. Here we explore the soil thermal regime of an ice-wedge polygon terrain near Utqiagvik (formerly Barrow) with the Water balance Simulation Model (WaSiM). WaSiM is a hydro-thermal model developed to simulate the water balance at the watershed scale and was recently refined to represent the hydrological processes unique to cold climates. WaSiM includes modules that represent surface runoff, evapotranspiration, groundwater, and soil moisture, while active layer freezing and thawing is based on a direct coupling of hydrological and thermal processes. A new snow module expands the vadose zone calculations into the snow pack, allowing the model to simulate the snow as a porous medium similar to soil. Together with a snow redistribution algorithm based on local topography, this latest addition to WaSiM makes simulation of the ground thermal regime much more accurate during winter months. Effective representation of ground temperatures during winter is crucial in the simulation of the permafrost thermal regime and allows for refined predictions of future ice-wedge degradation or stabilization.

Body, mother, mind: anorexia, femininity and the intrusive object.

PubMed

Lawrence, Marilyn

2002-08-01

This paper takes as its starting point the preponderance of female to male patients who suffer from anorexia. The author suggests that there may be something specific about certain experiences of femaleness which predispose towards anxieties of intrusion. Two contemporary theories of the aetiology of anorexia are outlined. Both of these suggest that the problem has its origins in intrusion or invasion of different sorts. The author suggests that many women who suffer from anorexia have an intrusive object instated in their minds, which may not necessarily be the result of actual intrusions in external reality. In the final part of the paper, the author examines the intrusiveness of anorexic patients in the transference and suggests that such patients very often harbour profound phantasies of intruding between the parents, with a wish to regain their special place with mother, untroubled by the presence of father. It is further suggested that the psychopathology underlying certain cases of anorexia leads to a failure in symbolisation. This failure in turn complicates the clinical picture, making such patients particularly difficult to think with about their difficulties.

A novel interacting multiple model based network intrusion detection scheme

NASA Astrophysics Data System (ADS)

Xin, Ruichi; Venkatasubramanian, Vijay; Leung, Henry

2006-04-01

In today's information age, information and network security are of primary importance to any organization. Network intrusion is a serious threat to security of computers and data networks. In internet protocol (IP) based network, intrusions originate in different kinds of packets/messages contained in the open system interconnection (OSI) layer 3 or higher layers. Network intrusion detection and prevention systems observe the layer 3 packets (or layer 4 to 7 messages) to screen for intrusions and security threats. Signature based methods use a pre-existing database that document intrusion patterns as perceived in the layer 3 to 7 protocol traffics and match the incoming traffic for potential intrusion attacks. Alternately, network traffic data can be modeled and any huge anomaly from the established traffic pattern can be detected as network intrusion. The latter method, also known as anomaly based detection is gaining popularity for its versatility in learning new patterns and discovering new attacks. It is apparent that for a reliable performance, an accurate model of the network data needs to be established. In this paper, we illustrate using collected data that network traffic is seldom stationary. We propose the use of multiple models to accurately represent the traffic data. The improvement in reliability of the proposed model is verified by measuring the detection and false alarm rates on several datasets.

Unlocking the Secrets of the Mantle Wedge: New Insights Into Melt Generation Processes in Subduction Zones

NASA Astrophysics Data System (ADS)

Grove, T. L.

2007-05-01

Recent laboratory studies of the melting and crystallization behavior of mantle peridotite and subduction zone lavas have led to new insights into melting processes in island arc settings. Melting of the mantle wedge in the presence of H2O begins at much lower temperatures than previously thought. The solidus of mantle peridotite at 3 GPa is ~ 800 °C, which is 200 °C below previous estimates. At pressures greater than 2.4 GPa chlorite becomes a stable phase on the solidus and it remains stable until ~ 3.5 GPa. Therefore, melting over this pressure range occurs in the presence of chlorite, which contains ~ 12 wt. % H2O. Chlorite stabilized on the peridotite solidus by slab-derived H2O may be the ultimate source of H2O for subduction zone magmatism. Thus, chlorite could transport large amounts of H2O into the descending mantle wedge to depths where it can participate in melting to generate hydrous arc magmas. Our ability to identify primitive mantle melts at subduction zones has led to the following observations. 1) Primitive mantle melts show evidence of final equilibration at shallow depths near the mantle - crust boundary. 2) They contain variable amounts of dissolved H2O (up to 6 wt. %). 3) They record variable extents of melting (up to > 25 wt. %). To produce melts with such variable characteristics requires more than one melting process and requires consideration of a new type of melting called hydrous flux melting. Flux melting occurs when the H2O - rich melt initially produced on the solidus near the base of the mantle wedge ascends and continuously reacts with overlying hotter, shallower mantle. The mantle melts and magmatic H2O content is constantly diluted as the melt ascends and reacts with shallower, hotter mantle. Anhydrous mantle melts are also found in close temporal and spatial proximity to hydrous flux melts. These melts are extracted at similar depths near the top of the mantle wedge when mantle is advected up and into the wedge corner and melted

Lateral Wedge Insoles as a Conservative Treatment for Pain in Patients With Medial Knee Osteoarthritis

PubMed Central

Parkes, Matthew J.; Maricar, Nasimah; Lunt, Mark; LaValley, Michael P.; Jones, Richard K.; Segal, Neil A.; Takahashi-Narita, Kayoko; Felson, David T.

2015-01-01

IMPORTANCE There is no consensus regarding the efficacy of lateral wedge insoles as a treatment for pain in medial knee osteoarthritis. OBJECTIVE To evaluate whether lateral wedge insoles reduce pain in patients with medial knee osteoarthritis compared with an appropriate control. DATA SOURCES Databases searched include the Cochrane Central Register of Controlled Trials, EMBASE, AMED, MEDLINE, CINAHL Plus, ScienceDirect, SCOPUS, Web of Science, and BIOSIS from inception to May 2013, with no limits on study date or language. The metaRegister of Controlled Trials and the NHS Evidence website were also searched. STUDY SELECTION Included were randomized trials comparing shoe-based treatments (lateral heel wedge insoles or shoes with variable stiffness soles) aimed at reducing medial knee load, with a neutral or no wedge control condition in patients with painful medial knee osteoarthritis. Studies must have included patient-reported pain as an outcome. DATA EXTRACTION AND SYNTHESIS Trial data were extracted independently by 2 researchers using a standardized form. Risk of bias was assessed using the Cochrane Risk of Bias tool by 2 observers. Eligible studies were pooled using a random-effects approach. MAIN OUTCOME AND MEASURES Change in self-reported knee pain at follow-up. RESULTS Twelve trials met inclusion criteria with a total of 885 participants of whom 502 received lateral wedge treatment. The pooled standardized mean difference (SMD) suggested a favorable association with lateral wedges compared with control (SMD, −0.47; 95% CI, −0.80 to −0.14); however, substantial heterogeneity was present (I2 = 82.7%). This effect size represents an effect of −2.12 points on the 20-point Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain scale. Larger trials with a lower risk of bias suggested a null association. Meta-regression analyses showed that higher effect sizes (unstandardized β, 1.07 [95% CI, 0.28 to 1.87] for trials using a no treatment

The architecture of a network level intrusion detection system

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

Heady, R.; Luger, G.; Maccabe, A.

1990-08-15

This paper presents the preliminary architecture of a network level intrusion detection system. The proposed system will monitor base level information in network packets (source, destination, packet size, and time), learning the normal patterns and announcing anomalies as they occur. The goal of this research is to determine the applicability of current intrusion detection technology to the detection of network level intrusions. In particular, the authors are investigating the possibility of using this technology to detect and react to worm programs.

A Thick, Deformed Sedimentary Wedge in an Erosional Subduction Zone, Southern Costa Rica

NASA Astrophysics Data System (ADS)

Silver, E. A.; Kluesner, J. W.; Edwards, J. H.; Vannucchi, P.

2014-12-01

A paradigm of erosional subduction zones is that the lower part of the wedge is composed of strong, crystalline basement (Clift and Vannucchi, Rev. Geophys., 42, RG2001, 2004). The CRISP 3D seismic reflection study of the southern part of the Costa Rica subduction zone shows quite the opposite. Here the slope is underlain by a series of fault-cored anticlines, with faults dipping both landward and seaward that root into the plate boundary. Deformation intensity increases with depth, and young, near-surface deformation follows that of the deeper structures but with basin inversions indicating a dynamic evolution (Edwards et al., this meeting). Fold wavelength increases landward, consistent with the folding of a landward-thickening wedge. Offscraping in accretion is minimal because incoming sediments on the lower plate are very thin. Within the wedge, thrust faulting dominates at depth in the wedge, whereas normal faulting dominates close to the surface, possibly reflecting uplift of the deforming anticlines. Normal faults form a mesh of NNW and ENE-trending structures, whereas thrust faults are oriented approximately parallel to the dominant fold orientation, which in turn follows the direction of roughness on the subducting plate. Rapid subduction erosion just prior to 2 Ma is inferred from IODP Expedition 334 (Vannucchi et al., 2013, Geology, 49:995-998). Crystalline basement may have been largely removed from the slope region during this rapid erosional event, and the modern wedge may consist of rapidly redeposited material (Expedition 344 Scientists, 2013) that has been undergoing deformation since its inception, producing a structure quite different from that expected of an eroding subduction zone.

Impact of exogenous cortisol on the formation of intrusive memories in healthy women.

PubMed

Rombold, Felicitas; Wingenfeld, Katja; Renneberg, Babette; Schwarzkopf, Friederike; Hellmann-Regen, Julian; Otte, Christian; Roepke, Stefan

2016-12-01

Stress hormones such as cortisol are involved in modulating emotional memory. However, little is known about the influence of cortisol on the formation of intrusive memories after a traumatic event. The aim of this study was to examine whether cortisol levels during encoding and consolidation of an intrusion-inducing trauma film paradigm would influence subsequent intrusion formation. In an experimental, double-blind, placebo-controlled study a trauma film paradigm was used to induce intrusions in 60 healthy women. Participants received a single dose of either 20 mg hydrocortisone or placebo before watching a trauma film. Salivary cortisol and alpha-amylase as well as blood pressure were measured during the experiment. The consecutive number of intrusions, the vividness of intrusions, and the degree of distress evoked by the intrusions resulting from the trauma film were assessed throughout the following seven days. Hydrocortisone administration before the trauma film resulted in increased salivary cortisol levels but did not affect the consecutive number of intrusions, the vividness of intrusions, and the degree of distress evoked by the intrusions throughout the following week. These results indicate that pharmacologically increased cortisol levels during an experimental trauma film paradigm do not influence consecutive intrusive memories. Current data do not support a prominent role of exogenous cortisol on intrusive memories, at least in healthy young women after a relatively mild trauma equivalent. Copyright © 2016 Elsevier Ltd. All rights reserved.

Salt tolerant plants increase nitrogen removal from biofiltration systems affected by saline stormwater.

PubMed

Szota, Christopher; Farrell, Claire; Livesley, Stephen J; Fletcher, Tim D

2015-10-15

Biofiltration systems are used in urban areas to reduce the concentration and load of nutrient pollutants and heavy metals entering waterways through stormwater runoff. Biofilters can, however be exposed to salt water, through intrusion of seawater in coastal areas which could decrease their ability to intercept and retain pollutants. We measured the effect of adding saline stormwater on pollutant removal by six monocotyledonous species with different levels of salt-tolerance. Carex appressa, Carex bichenoviana, Ficinia nodosa, Gahnia filum, Juncus kraussii and Juncus usitatus were exposed to six concentrations of saline stormwater, equivalent to electrical conductivity readings of: 0.09, 2.3, 5.5, 10.4, 20.0 and 37.6 mS cm(-1). Salt-sensitive species: C. appressa, C. bichenoviana and J. usitatus did not survive ≥10.4 mS cm(-1), removing their ability to take up nitrogen (N). Salt-tolerant species, such as F. nodosa and J. kraussii, maintained N-removal even at the highest salt concentration. However, their levels of water stress and stomatal conductance suggest that N-removal would not be sustained at concentrations ≥10.4 mS cm(-1). Increasing salt concentration indirectly increased phosphorus (P) removal, by converting dissolved forms of P to particulate forms which were retained by filter media. Salt concentrations ≥10 mS cm(-1) also reduced removal efficiency of zinc, manganese and cadmium, but increased removal of iron and lead, regardless of plant species. Our results suggest that biofiltration systems exposed to saline stormwater ≤10 mS cm(-1) can only maintain N-removal when planted with salt-tolerant species, while P removal and immobilisation of heavy metals is less affected by species selection. Copyright © 2015 Elsevier Ltd. All rights reserved.

Augmented wedge-shaped glenoid component for the correction of glenoid retroversion: a finite element analysis.

PubMed

Hermida, Juan C; Flores-Hernandez, Cesar; Hoenecke, Heinz R; D'Lima, Darryl D

2014-03-01

This study undertook a computational analysis of a wedged glenoid component for correction of retroverted glenoid arthritic deformity to determine whether a wedge-shaped glenoid component design with a built-in correction for version reduces excessive stresses in the implant, cement, and glenoid bone. Recommendations for correcting retroversion deformity are asymmetric reaming of the anterior glenoid, bone grafting of the posterior glenoid, or a glenoid component with posterior augmentation. Eccentric reaming has the disadvantages of removing normal bone, reducing structural support for the glenoid component, and increasing the risk of bone perforation by the fixation pegs. Bone grafting to correct retroverted deformity does not consistently generate successful results. Finite element models of 2 scapulae models representing a normal and an arthritic retroverted glenoid were implanted with a standard glenoid component (in retroversion or neutral alignment) or a wedged component. Glenohumeral forces representing in vivo loading were applied and stresses and strains computed in the bone, cement, and glenoid component. The retroverted glenoid components generated the highest compressive stresses and decreased cyclic fatigue life predictions for trabecular bone. Correction of retroversion by the wedged glenoid component significantly decreased stresses and predicted greater bone fatigue life. The cement volume estimated to survive 10 million cycles was the lowest for the retroverted components and the highest for neutrally implanted glenoid components and for wedged components. A wedged glenoid implant is a viable option to correct severe arthritic retroversion, reducing the need for eccentric reaming and the risk for implant failure. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Saltwater Intrusion and its Long-Term Consequences in a Coastal Alluvial Aquifer of Northern Oman

NASA Astrophysics Data System (ADS)

Weyhenmeyer, C. E.; Waber, H. N.

2002-12-01

The alluvial aquifer of the Eastern Batinah coastal plain supplies water for the most densely populated, cultivated and industrialized areas in the Sultanate of Oman. In recent years, overexploitation of these groundwater resources has resulted in a drastic lowering of the groundwater table and consequent seawater intrusion into the coastal aquifer sections. During recent drilling operations near the coast (~3 km) groundwater samples were taken at depths intervals of 2-5 m. The front of the saline intrusion wedge was encountered at a depth of 70-80 mbs as suggested by sudden changes in groundwater chemistry and isotope values. Groundwater near the saline intrusion front is characterized by lower Na/Cl and higher Ca/Mg ratios compared to ion ratios expected from groundwater mixing calculations between fresh- and saltwater. The observed changes in ion ratios suggest that Na is removed from the groundwater and replaced by Ca from cation exchange surfaces in the aquifer (e.g., clay particles), which is an indication that the saline front is still migrating inland. To date, a deterioration of overall groundwater quality can be recognized as far inland as 15 km and Cl and Na concentrations in these areas are well above the general quality standards for drinking water. Estimates of infiltration rates based on isotope ratios (Sr, O, H) suggest that less than 10% of the total groundwater recharge occurs on the coastal plain itself, with the remaining 90% originating in the adjacent Oman Mountains. Groundwater residence times on the coastal plain are in the order of a few hundred to several thousand years as suggested by a number of radioactive isotopes (3H, 85Kr, 39Ar, 14C). Therefore, these groundwater resources essentially have to be considered non-renewable and there is a pressing requirement for the development of sustainable groundwater management strategies. Attempts to artificially increase infiltration on the coastal plain by the construction of large recharge dams

Effect of a pelvic wedge and belt on the medial and lateral hamstring muscles during knee flexion.

PubMed

Yoo, Won-Gyu

2017-01-01

[Purpose] This study developed a pelvic wedge and belt and investigated their effects on the selective activation of medial and lateral hamstring muscles during knee flexion. [Subjects and Methods] Nine adults were enrolled. The participants performed exercises without and with the pelvic wedge and belt, and the electromyographic activities of the medial and lateral hamstring muscles were recorded. [Results] The activity of the medial hamstring was increased significantly when using the pelvic wedge and belt, while the activity of the lateral hamstring did not differ significantly. [Conclusion] The pelvic wedge and belt provide a self-locked position during knee flexion in the prone position. Prone knee flexion in this position is an effective self-exercise for balanced strengthening of the medial hamstring.

Effect of a pelvic wedge and belt on the medial and lateral hamstring muscles during knee flexion

PubMed Central

Yoo, Won-gyu

2017-01-01

[Purpose] This study developed a pelvic wedge and belt and investigated their effects on the selective activation of medial and lateral hamstring muscles during knee flexion. [Subjects and Methods] Nine adults were enrolled. The participants performed exercises without and with the pelvic wedge and belt, and the electromyographic activities of the medial and lateral hamstring muscles were recorded. [Results] The activity of the medial hamstring was increased significantly when using the pelvic wedge and belt, while the activity of the lateral hamstring did not differ significantly. [Conclusion] The pelvic wedge and belt provide a self-locked position during knee flexion in the prone position. Prone knee flexion in this position is an effective self-exercise for balanced strengthening of the medial hamstring. PMID:28210048

Toddler Inhibited Temperament, Maternal Cortisol Reactivity and Embarrassment, and Intrusive Parenting

PubMed Central

Kiel, Elizabeth J.; Buss, Kristin A.

2013-01-01

The relevance of parenting behavior to toddlers’ development necessitates a better understanding of the influences on parents during parent-child interactions. Toddlers’ inhibited temperament may relate to parenting behaviors, such as intrusiveness, that predict outcomes later in childhood. The conditions under which inhibited temperament relates to intrusiveness, however, remain understudied. A multi-method approach would acknowledge that several levels of processes determine mothers’ experiences during situations in which they witness their toddlers interacting with novelty. As such, the current study examined maternal cortisol reactivity and embarrassment about shyness as moderators of the relation between toddlers’ inhibited temperament and maternal intrusive behavior. Participants included 92 24-month-olds toddlers and their mothers. Toddlers’ inhibited temperament and maternal intrusiveness were measured observationally in the laboratory. Mothers supplied saliva samples at the beginning of the laboratory visit and 20 minutes after observation. Maternal cortisol reactivity interacted with inhibited temperament in relation to intrusive behavior, such that mothers with higher levels of cortisol reactivity were observed to be more intrusive with more highly inhibited toddlers. Embarrassment related to intrusive behavior as a main effect. These results highlight the importance of considering child characteristics and psychobiological processes in relation to parenting behavior. PMID:23750532

Performance Assessment of Network Intrusion-Alert Prediction

DTIC Science & Technology

2012-09-01

the threats. In this thesis, we use Snort to generate the intrusion detection alerts. 2. SNORT Snort is an open source network intrusion...standard for IPS. (Snort, 2012) We choose Snort because it is an open source product that is free to download and can be deployed cross-platform...Learning & prediction in relational time series: A survey. 21st Behavior Representation in Modeling & Simulation ( BRIMS ) Conference 2012, 93–100. Tan

Sandbox Simulations of the Evolution of a Subduction Wedge following Subduction Initiation

NASA Astrophysics Data System (ADS)

Brandon, M. T.; Ma, K. F.; DeWolf, W.

2012-12-01

Subduction wedges at accreting subduction zones are bounded by a landward dipping pro-shear zone (= subduction thrust) and a seaward-dipping retro-shear zone in the overriding plate. For the Cascadia subduction zone, the surface trace of the retro-shear zone corresponds to the east side of the Coast Ranges of Oregon and Washington and the Insular Mountains of Vancouver Island. This coastal high or forearc high shows clear evidence of long-term uplift and erosion along its entire length, indicating that it is an active part of the Cascadia subduction wedge. The question addressed here is what controls the location of the retro-shear zone? In the popular double-sided wedge model of Willet et al (Geology 1993), the retro-shear zone remains pinned to the S point, which is interpreted to represent where the upper-plate Moho intersects the subduction zone. For this interpretation, the relatively strong mantle is considered to operate as a flat backstop. That model, however. is somewhat artificial in that the two plates collide in a symmetric fashion with equal crustal thicknesses on both sides. Using sandbox experiments, we explore a more realistic configuration where the upper and lower plate are separated by a gentle dipping (10 degree) pro-shear zone, to simulate the initial asymmetric geometry of the subduction thrust immediately after initiation of subduction. The entire lithosphere must fail along some plane for subduction to begin and this failure plane must dip in the direction of subduction. Thus, the initial geometry of the overriding plate is better approximated as a tapered wedge than as a layer of uniform thickness, as represented in the Willett et al models. We demonstrate this model using time-lapse movies of a sand wedge above a mylar subducting plate. We use particle image velocimetry (PIV) to show the evolution of strain and structure within the overriding plate. Material accreted to the tapered end of the overriding plate drives deformation and causes

Salt Attack on Rocks and Expansion of Soils on Mars

NASA Astrophysics Data System (ADS)

Vaniman, D. T.; Bish, D. L.; Chipera, S. J.; Carey, J. W.

2004-12-01

Salt-rich sediments observed by the MER rover Opportunity at Meridiani Planum show that brines have been present on Mars in the past, but a role for groundwater in widespread rock weathering and soil formation is uncertain. Experiments by several groups suggest instead the action of acid fog over long time spans, with episodic input of volcanic gases, as a more significant agent of Mars weathering. Salt minerals formed in these acid weathering experiments consistently include gypsum and alunogen, with epsomite or hexahydrite forming where olivine provides a source of Mg. Analogous to the martian acid fog scenario are terrestrial acid rain or acid fog attacks on building and monument stone by chemical action and mechanical wedging through growth of gypsum, anhydrite, epsomite, hexahydrite, kieserite, and other sulfate minerals. Physical effects can be aggressive, operating by both primary salt growth and hydration of anhydrous or less-hydrous primary salts. In contrast, soils evolve to states where chemical attack is lessened and salt mineral growth leads to expansion with cementation; in this situation the process becomes constructive rather than destructive. We have made synthetic salt-cemented soils (duricrusts) from clays, zeolites, palagonites and other media mixed with ultrapure Mg-sulfate solutions. Although near-neutral in pH, these solutions still exchange or leach Ca from the solids to form cements containing gypsum as well as hexahydrite. At low total P (1 torr) and low RH (<1%) hexahydrite becomes amorphous but gypsum does not. If allowed to rehydrate from vapor at higher RH, the Mg-sulfate component of the duricrust expands by formation of a complex mixture of Mg-sulfate phases with various hydration states. The expanded form is retained even if the duricrust is again dehydrated, suggesting that soil porosity thus formed is difficult to destroy. These processes can be considered in the context of Viking, Pathfinder, and MER evidence for differing salt

Realistic computer network simulation for network intrusion detection dataset generation

NASA Astrophysics Data System (ADS)

Payer, Garrett

2015-05-01

The KDD-99 Cup dataset is dead. While it can continue to be used as a toy example, the age of this dataset makes it all but useless for intrusion detection research and data mining. Many of the attacks used within the dataset are obsolete and do not reflect the features important for intrusion detection in today's networks. Creating a new dataset encompassing a large cross section of the attacks found on the Internet today could be useful, but would eventually fall to the same problem as the KDD-99 Cup; its usefulness would diminish after a period of time. To continue research into intrusion detection, the generation of new datasets needs to be as dynamic and as quick as the attacker. Simply examining existing network traffic and using domain experts such as intrusion analysts to label traffic is inefficient, expensive, and not scalable. The only viable methodology is simulation using technologies including virtualization, attack-toolsets such as Metasploit and Armitage, and sophisticated emulation of threat and user behavior. Simulating actual user behavior and network intrusion events dynamically not only allows researchers to vary scenarios quickly, but enables online testing of intrusion detection mechanisms by interacting with data as it is generated. As new threat behaviors are identified, they can be added to the simulation to make quicker determinations as to the effectiveness of existing and ongoing network intrusion technology, methodology and models.

Three-dimensional semi-analytical solution to groundwater flow in confined and unconfined wedge-shaped aquifers

NASA Astrophysics Data System (ADS)

Sedghi, Mohammad Mahdi; Samani, Nozar; Sleep, Brent

2009-06-01

The Laplace domain solutions have been obtained for three-dimensional groundwater flow to a well in confined and unconfined wedge-shaped aquifers. The solutions take into account partial penetration effects, instantaneous drainage or delayed yield, vertical anisotropy and the water table boundary condition. As a basis, the Laplace domain solutions for drawdown created by a point source in uniform, anisotropic confined and unconfined wedge-shaped aquifers are first derived. Then, by the principle of superposition the point source solutions are extended to the cases of partially and fully penetrating wells. Unlike the previous solution for the confined aquifer that contains improper integrals arising from the Hankel transform [Yeh HD, Chang YC. New analytical solutions for groundwater flow in wedge-shaped aquifers with various topographic boundary conditions. Adv Water Resour 2006;26:471-80], numerical evaluation of our solution is relatively easy using well known numerical Laplace inversion methods. The effects of wedge angle, pumping well location and observation point location on drawdown and the effects of partial penetration, screen location and delay index on the wedge boundary hydraulic gradient in unconfined aquifers have also been investigated. The results are presented in the form of dimensionless drawdown-time and boundary gradient-time type curves. The curves are useful for parameter identification, calculation of stream depletion rates and the assessment of water budgets in river basins.

Railway clearance intrusion detection method with binocular stereo vision

NASA Astrophysics Data System (ADS)

Zhou, Xingfang; Guo, Baoqing; Wei, Wei

2018-03-01

In the stage of railway construction and operation, objects intruding railway clearance greatly threaten the safety of railway operation. Real-time intrusion detection is of great importance. For the shortcomings of depth insensitive and shadow interference of single image method, an intrusion detection method with binocular stereo vision is proposed to reconstruct the 3D scene for locating the objects and judging clearance intrusion. The binocular cameras are calibrated with Zhang Zhengyou's method. In order to improve the 3D reconstruction speed, a suspicious region is firstly determined by background difference method of a single camera's image sequences. The image rectification, stereo matching and 3D reconstruction process are only executed when there is a suspicious region. A transformation matrix from Camera Coordinate System(CCS) to Track Coordinate System(TCS) is computed with gauge constant and used to transfer the 3D point clouds into the TCS, then the 3D point clouds are used to calculate the object position and intrusion in TCS. The experiments in railway scene show that the position precision is better than 10mm. It is an effective way for clearance intrusion detection and can satisfy the requirement of railway application.

The chronology of Late Pleistocene thermal contraction cracking derived from sand wedge OSL dating in central and southern France

NASA Astrophysics Data System (ADS)

Andrieux, Eric; Bateman, Mark D.; Bertran, Pascal

2018-03-01

Much of France remained unglaciated during the Late Quaternary and was subjected to repeated phases of periglacial activity. Numerous periglacial features have been reported but disentangling the environmental and climatic conditions they formed under, the timing and extent of permafrost and the role of seasonal frost has remained elusive. The primary sandy infillings of relict sand-wedges and composite-wedge pseudomorphs record periglacial activity. As they contain well-bleached quartz-rich aeolian material they are suitable for optically stimulated luminescence dating (OSL). This study aims to reconstruct when wedge activity took place in two regions of France; Northern Aquitaine and in the Loire valley. Results from single-grain OSL measurements identify multiple phases of activity within sand wedges which suggest that wedge activity in France occurred at least 11 times over the last 100 ka. The most widespread events of thermal contraction cracking occurred between ca. 30 and 24 ka (Last Permafrost Maximum) which are concomitant with periods of high sand availability (MIS 2). Although most phases of sand-wedge growth correlate well with known Pleistocene cold periods, the identification of wedge activity during late MIS 5 and the Younger Dryas strongly suggests that these features do not only indicate permafrost but also deep seasonal ground freezing in the context of low winter insolation. These data also suggest that the overall young ages yielded by North-European sand-wedges likely result from poor record of periglacial periods concomitant with low sand availability and/or age averaging inherent with standard luminescence methods.

BTSC VAPOR INSTRUSION PRIMER "VAPOR INTRUSION CONSIDERATION FOR REDEVELOPMENT"

EPA Science Inventory

This primer is designed for brownfields stakeholders concerned about vapor intrusion, including property owners, real estate developers, and contractors performing environmental site investigations. It provides an overview of the vapor intrusion issue and how it can impact the ap...

Dose conformation to the spine during palliative treatments using dynamic wedges

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

Ormsby, Matthew A., E-mail: Matthew.Ormsby@usoncology.com; Herndon, R. Craig; Kaczor, Joseph G.

2013-07-01

Radiation therapy is commonly used to alleviate pain associated with metastatic disease of the spine. Often, isodose lines are manipulated using dynamic or physical wedges to encompass the section of spine needing treatment while minimizing dose to normal tissue. We will compare 2 methods used to treat the entire thoracic spine. The first method treats the thoracic spine with a single, nonwedged posterior-anterior (PA) field. Dose is prescribed to include the entire spine. Isodose lines tightly conform to the top and bottom vertebrae, but vertebrae between these 2 received more than enough coverage. The second method uses a combination ofmore » wedges to create an isodose line that mimics the curvature of the thoracic spine. This “C”-shaped curvature is created by overlapping 2 fields with opposing dynamic wedges. Machine constraints limit the treatment length and therefore 2 isocenters are used. Each of the 2 PA fields contributes a portion of the total daily dose. This technique creates a “C”-shaped isodose line that tightly conforms to the thoracic spine, minimizing normal tissue dose. Spinal cord maximum dose is reduced, as well as mean dose to the liver, esophagus, and heart.« less

Online Adaboost-Based Parameterized Methods for Dynamic Distributed Network Intrusion Detection.

PubMed

Hu, Weiming; Gao, Jun; Wang, Yanguo; Wu, Ou; Maybank, Stephen

2014-01-01

Current network intrusion detection systems lack adaptability to the frequently changing network environments. Furthermore, intrusion detection in the new distributed architectures is now a major requirement. In this paper, we propose two online Adaboost-based intrusion detection algorithms. In the first algorithm, a traditional online Adaboost process is used where decision stumps are used as weak classifiers. In the second algorithm, an improved online Adaboost process is proposed, and online Gaussian mixture models (GMMs) are used as weak classifiers. We further propose a distributed intrusion detection framework, in which a local parameterized detection model is constructed in each node using the online Adaboost algorithm. A global detection model is constructed in each node by combining the local parametric models using a small number of samples in the node. This combination is achieved using an algorithm based on particle swarm optimization (PSO) and support vector machines. The global model in each node is used to detect intrusions. Experimental results show that the improved online Adaboost process with GMMs obtains a higher detection rate and a lower false alarm rate than the traditional online Adaboost process that uses decision stumps. Both the algorithms outperform existing intrusion detection algorithms. It is also shown that our PSO, and SVM-based algorithm effectively combines the local detection models into the global model in each node; the global model in a node can handle the intrusion types that are found in other nodes, without sharing the samples of these intrusion types.

Appraisal and control of sexual and non-sexual intrusive thoughts in university students.

PubMed

Clark, D A; Purdon, C; Byers, E S

2000-05-01

This study examined differences in the appraisal and thought control strategies associated with the perceived control of unwanted sexual and non-sexual intrusive thoughts. Eleven appraisal dimensions, subjective physiological arousal and 10 thought control strategies were measured in 171 university students who were administered the Revised Obsessive Intrusions Inventory-Sex Version, a self-report measure of unwanted intrusive thoughts. Thought-action fusion (TAF) likelihood was a significant unique predictor of the perceived controllability of respondents' most upsetting sexual and non-sexual intrusive thought. Moreover greater subjective physiological arousal was a significant predictor of reduced control over sexual intrusions, whereas worry that one might act on an intrusive thought and greater effort to control the intrusion were significant unique predictors of the control of non-sexual intrusive thoughts. Various thought control strategies were more often used in response to non-sexual than sexual cognitions. The results are discussed in terms of the differential role of various appraisal processes in the control of unwanted sexual and non-sexual thoughts.

Tectono-stratigraphic evolution of salt-controlled minibasins in a fold and thrust belt, the Oligo-Miocene central Sivas Basin

NASA Astrophysics Data System (ADS)

Kergaravat, Charlie; Ribes, Charlotte; Callot, Jean-Paul; Ringenbach, Jean-Claude

2017-09-01

The Central Sivas Basin (Turkey) provides an outcrop example of a minibasin province developed above a salt canopy within a foreland-fold and thrust belt. Several minibasins are examined to assess the influence of regional Oligo-Miocene shortening during the development of a minibasin province. The results are based on extensive field work, including regional and detailed outcrop mapping of at least 15 minibasin margins and analysis of the structural elements at all scales. This reveals a progressive increase in shortening and a decrease in salt tectonics during evolution of the province. The initiation of minibasins is driven mostly by the salt-induced accommodation forming a polygonal network of salt structures with mainly local halokinetic sequences (i.e. hooks and wedges). The initiation of shortening is marked by an abrupt increase in sedimentation rate within the flexural foreland basin causing burial of the preexisting salt structures. Subsequently, orogenic compression encourages the rejuvenation of linear salt structures oriented at right angle to the regional shortening direction. The influence of orogenic shortening during the last steps of the minibasin province evolution is clearly shown by: (i) the squeezing of salt structures to form welds which are developed both at right angle and oblique to the regional shortening direction, (ii) the emergence of thrust faults, (iii) the tilting and rotation of minibasins about vertical axis associated with the formation of strike-slip fault zones, and (iv) the extrusion of salt sheets. The pre-shortening geometry of the salt structures pattern, polygonal network of walls and diapirs versus linear and sub-parallel walls, influence the resultant structural style of the minibasin province subjected to shortening. Preexisting linear depocenter limited by sub-parallel walls accommodate preferentially the shortening compare to the preexisting sub-circular depocenter limited by polygonal network of salt walls and

Gastric Volvulus with Segmental Necrosis Treated with Wedge Resection and Gastrogastrostomy.

PubMed

Merz, Alexa Elizabeth; Preston, Jennifer Francis

2017-12-01

Ischemic necrosis is a feared complication of acute gastric volvulus, occurring in 11% of patients presenting with the condition and responsible for mortality in 30%. In such cases, there are few well-validated options for surgical reconstruction. We present the case of a 77-year-old woman with intraabdominal mesenteroaxial gastric volvulus with segmental ischemic gastric necrosis who underwent wedge gastrectomy and hand-sewn gastrogastrostomy. She did well postoperatively and experienced no significant gastrointestinal complications. Gastric wedge resection with gastrogastrostomy presents a novel surgical intervention for a rare and highly morbid entity. We hope to add it to the repertoire of surgeons facing acute gastric volvulus complicated by segmental necrosis.

Local transmural action potential gradients are absent in the isolated, intact dog heart but present in the corresponding coronary-perfused wedge.

PubMed

Boukens, Bastiaan J; Meijborg, Veronique M F; Belterman, Charly N; Opthof, Tobias; Janse, Michiel J; Schuessler, Richard B; Coronel, Ruben; Efimov, Igor R

2017-05-01

The left ventricular (LV) coronary-perfused canine wedge preparation is a model commonly used for studying cardiac repolarization. In wedge studies, transmembrane potentials typically are recorded; whereas, extracellular electrical recordings are commonly used in intact hearts. We compared electrically measured activation recovery interval (ARI) patterns in the intact heart with those recorded at the same location in the LV wedge preparation. We also compared electrically recorded and optically obtained ARIs in the LV wedge preparation. Five Langendorff-perfused canine hearts were paced from the right atrium. Local activation and repolarization times were measured with eight transmural needle electrodes. Subsequently, left ventricular coronary-perfused wedge preparations were prepared from these hearts while the electrodes remained in place. Three electrodes remained at identical positions as in the intact heart. Both electrograms and optical action potentials were recorded (pacing cycle length 400-4000 msec) and activation and repolarization patterns were analyzed. ARIs found in the subepicardium were shorter than in the subendocardium in the LV wedge preparation but not in the intact heart. The transmural ARI gradient recorded at the cut surface of the wedge was not different from that recorded internally. ARIs recorded internally and at the cut surface in the LV wedge preparation, both correlated with optically recorded action potentials. ARI and RT gradients in the LV wedge preparation differed from those in the intact canine heart, implying that those observations in human LV wedge preparations also should be extrapolated to the intact human heart with caution. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Complex interactions between diapirs and 4-D subduction driven mantle wedge circulation.

NASA Astrophysics Data System (ADS)

Sylvia, R. T.; Kincaid, C. R.

2015-12-01

Analogue laboratory experiments generate 4-D flow of mantle wedge fluid and capture the evolution of buoyant mesoscale diapirs. The mantle is modeled with viscous glucose syrup with an Arrhenius type temperature dependent viscosity. To characterize diapir evolution we experiment with a variety of fluids injected from multiple point sources. Diapirs interact with kinematically induced flow fields forced by subducting plate motions replicating a range of styles observed in dynamic subduction models (e.g., rollback, steepening, gaps). Data is collected using high definition timelapse photography and quantified using image velocimetry techniques. While many studies assume direct vertical connections between the volcanic arc and the deeper mantle source region, our experiments demonstrate the difficulty of creating near vertical conduits. Results highlight extreme curvature of diapir rise paths. Trench-normal deflection occurs as diapirs are advected downward away from the trench before ascending into wedge apex directed return flow. Trench parallel deflections up to 75% of trench length are seen in all cases, exacerbated by complex geometry and rollback motion. Interdiapir interaction is also important; upwellings with similar trajectory coalesce and rapidly accelerate. Moreover, we observe a new mode of interaction whereby recycled diapir material is drawn down along the slab surface and then initiates rapid fluid migration updip along the slab-wedge interface. Variability in trajectory and residence time leads to complex petrologic inferences. Material from disparate source regions can surface at the same location, mix in the wedge, or become fully entrained in creeping flow adding heterogeneity to the mantle. Active diapirism or any other vertical fluid flux mechanism employing rheological weakening lowers viscosity in the recycling mantle wedge affecting both solid and fluid flow characteristics. Many interesting and insightful results have been presented based

Linking Serpentinite Geochemistry with Possible Alteration and Evolution of Supra-Subduction Wedge Mantle

NASA Astrophysics Data System (ADS)

Scambelluri, M.; Cannaò, E.; Agostini, S.; Gilio, M.

2016-12-01

Serpentinites are able to transport and release volatiles and fluid-mobile elements (FME) found in arc magmas. Constraining the trace element compositions of these rocks and of fluids released by de-serpentinization improves our knowledge of mass transfer from subduction zones to volcanic arcs, and of the role of slab and wedge mantle in this global process. Studies of high-pressure ultramafic rocks exhumed from plate interface settings reveal the fluid/rock interactions atop the slab and the processes that can affect the mantle wedge. Alpine eclogite-facies antigorite serpentinite (Voltri Massif) and fully de-serpentinized meta-peridotite (Cima di Gagnone) are enriched in sediment-derived As, Sb, U, Pb before peak dehydration. Their Sr, Pb and B isotopic compositions are reset during prograde (forearc) interaction with slab fluids. The eclogitic garnet and olivine from the Cima di Gagnone metaperidotite trap primary inclusions of the fluid released during breakdown of antigorite and chlorite. The inclusions display FME enrichments (high Cl, S; variable Cs, Rb, Ba, B, Pb, As, Sb) indicating element release from rocks to fluids during dehydration under subarc conditions. Our studies show that serpentinized mantle rocks from subduction zones sequester FME from slab fluids and convey these components and radiogenic isotopes into the mantle wedge upon dehydration. The geochemical processes revealed by such plate-interface rocks can apply to the supra-subduction mantle. Shallow element release from slabs to mantle wedge, downdrag of this altered mantle and its subsequent (subarc) dehydration transfers crust-derived FMEs to the arc magma sources without the need of concomitant subarc dehydration/melting of metasedimentary slab components. The slab signature detected in arc lavas can thus result from geochemical mixing of sediment, oceanic crust and ultramafic reservoirs into altered wedge-mantle rocks, rather than being attributed to multiple fluids.

[Postoperative complications of labia minora reduction. Comparative study between wedge and edge resection].

PubMed

Ouar, N; Guillier, D; Moris, V; Revol, M; Francois, C; Cristofari, S

2017-06-01

Labia minora reduction interventions rise in Europe and in North America. Several techniques are described. The objective of this study was to compare postoperative complications of the two most practiced interventions: wedge resection and edge resection. Primary labia minora reductions realized in our unit between October 2009 and July 2016 have been retrospectively identified. Two techniques were used by two surgeons: edge resection technique and wedge resection technique. The main evaluation criterion was the occurrence and the quantity of wound dehiscence: superior to 50% (total or subtotal) and inferior to 50% (partial). Patients were systematically examined at 1 week, 1 month and 6 months postoperatively. Data analysis between both groups was made with an exact Fisher test. Mean follow-up was 5.3 months after intervention. Sixty-four patients have been included, 42 wedge resections (group C) and 22 edge resections (group L). Global complication rate at 1 month was 13% (n=8). Among wedge resections 14% (n=6) developed complication and 2% (n=9) among edge resection. Seven surgical revisions were necessary: 5 for wound dehiscence (4 in the group C and 1 in the group L) and 2 for hematoma, one in each group. Three (5%) partial wound dehiscence (inferior to 50%) have been identified and let in secondary intention healing: 2 (19%) in the group C and 1 (27%) in the group L. Complication rates between both techniques were not significantly different. Postoperative wound dehiscence is the main labia minora reduction complication. Our global complication rate, 13%, matches with the current literature. A tendency can be shown where wedge resection is more likely to develop wound dehiscence than edge resection. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Proximal Opening Wedge Osteotomy Provides Satisfactory Midterm Results With a Low Complication Rate.

PubMed

Oravakangas, Rami; Leppilahti, Juhana; Laine, Vesa; Niinimäki, Tuukka

2016-01-01

Hallux valgus is one of the most common foot deformities. Proximal opening wedge osteotomy is used for the treatment of moderate and severe hallux valgus with metatarsus primus varus. However, hypermobility of the first tarsometatarsal joint can compromise the results of the operation, and a paucity of midterm results are available regarding proximal open wedge osteotomy surgery. The aim of the present study was to assess the midterm results of proximal open wedge osteotomy in a consecutive series of patients with severe hallux valgus. Thirty-one consecutive adult patients (35 feet) with severe hallux valgus underwent proximal open wedge osteotomy. Twenty patients (35.5%) and 23 feet (34.3%) were available for the final follow-up examination. The mean follow-up duration was 5.8 (range 4.6 to 7.0) years. The radiologic measurements and American Orthopaedic Foot and Ankle Society hallux-metatarsophalangeal-interphalangeal scores were recorded pre- and postoperatively, and subjective questionnaires were completed and foot scan analyses performed at the end of the follow-up period. The mean hallux valgus angle decreased from 38° to 23°, and the mean intermetatarsal angle correction decreased from 17° to 10°. The mean improvement in the American Orthopaedic Foot and Ankle Society hallux metatarsophalangeal-interphalangeal score increased from 52 to 84. Two feet (5.7%) required repeat surgery because of recurrent hallux valgus. No nonunions were identified. Proximal open wedge osteotomy provided satisfactory midterm results in the treatment of severe hallux valgus, with a low complication rate. The potential instability of the first tarsometatarsal joint does not seem to jeopardize the midterm results of the operation. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Salt Intake and Health Risk in Climate Change Vulnerable Coastal Bangladesh: What Role Do Beliefs and Practices Play?

PubMed Central

Rasheed, Sabrina; Siddique, A. K.; Sharmin, Tamanna; Hasan, A. M. R.; Hanifi, S. M. A.; Iqbal, M.; Bhuiya, Abbas

2016-01-01

Background High salt consumption is an important risk factor of elevated blood pressure. In Bangladesh about 20 million people are at high risk of hypertension due to climate change induced saline intrusion in water. The objective of this study is to assess beliefs, perceptions, and practices associated with salt consumption in coastal Bangladesh. Methods The study was conducted in Chakaria, Bangladesh between April-June 2011. It was a cross sectional mixed method study. For the qualitative study 6 focus group discussions, 8 key informant interviews, 60 free listing exercises, 20 ranking exercises and 10 observations were conducted. 400 adults were randomly selected for quantitative survey. For analysis we used SPSS for quantitative data, and Anthropac and Nvivo for qualitative data. Results Salt was described as an essential component of food with strong cultural and religious roots. People described both health benefits and risks related to salt intake. The overall risk perception regarding excessive salt consumption was low and respondents believed that the cooking process can render the salt harmless. Respondents were aware that salt is added in many foods even if they do not taste salty but did not recognize that salt can occur naturally in both foods and water. Conclusions In the study community people had low awareness of the risks associated with excess salt consumption and salt reduction strategies were not high in their agenda. The easy access to and low cost of salt as well as unrecognised presence of salt in drinking water has created an environment conducive to excess salt consumption. It is important to design general messages related to salt reduction and test tailored strategies especially for those at high risk of hypertension. PMID:27044049

Three Dimensional Vapor Intrusion Modeling: Model Validation and Uncertainty Analysis

NASA Astrophysics Data System (ADS)

Akbariyeh, S.; Patterson, B.; Rakoczy, A.; Li, Y.

2013-12-01

Volatile organic chemicals (VOCs), such as chlorinated solvents and petroleum hydrocarbons, are prevalent groundwater contaminants due to their improper disposal and accidental spillage. In addition to contaminating groundwater, VOCs may partition into the overlying vadose zone and enter buildings through gaps and cracks in foundation slabs or basement walls, a process termed vapor intrusion. Vapor intrusion of VOCs has been recognized as a detrimental source for human exposures to potential carcinogenic or toxic compounds. The simulation of vapor intrusion from a subsurface source has been the focus of many studies to better understand the process and guide field investigation. While multiple analytical and numerical models were developed to simulate the vapor intrusion process, detailed validation of these models against well controlled experiments is still lacking, due to the complexity and uncertainties associated with site characterization and soil gas flux and indoor air concentration measurement. In this work, we present an effort to validate a three-dimensional vapor intrusion model based on a well-controlled experimental quantification of the vapor intrusion pathways into a slab-on-ground building under varying environmental conditions. Finally, a probabilistic approach based on Monte Carlo simulations is implemented to determine the probability distribution of indoor air concentration based on the most uncertain input parameters.

PGE and Re-Os Isotope Behaviour in a Subduction-Modified Mantle Wedge: A Fresh Look into the Peridotites from the Ulten Zone, Eastern Alps

NASA Astrophysics Data System (ADS)

Aulbach, S.; Braga, R.; Gudelius, D.; Prelevic, D.; Meisel, T. C.

2015-12-01

Peridotites in the upper Austroalpine Ulten zone (Eastern Italy) sample the subduction-modified Variscan mantle wedge. Metasomatism of peridotites during four stages of mantle wedge evolution includes: (1) Intrusion of alkaline melts from an inner, subduction-modified wedge and cryptic enrichment of spinel lherzolites (SL); (2) Reaction with siliceous crustal melts after pressure increase, generating coarse-grained garnet amphibole peridotites (GAP); (3) Crystallisation of abundant amphibole (± apatite and dolomite) from residual hydrous fluids during and/or after peak metamorphism recorded by fine-grained GAP; [4] Subsequent influx of crustal fluids, causing retrograde formation of spinel chlorite amphibole peridotites (SAP) [1-5]. SL and coarse GAP are apparently more fertile, whereas fine GAP and SAP retain the most depleted major-element characteristics. Overall, samples fall on partial melting trends consistent with extraction of low degrees of melt (F≤0.15) at 2-1 GPa. SL and coarse GAP have ±flat PGE patterns normalised to Primitive Upper Mantle (PUM), or show small decreases or increases from compatible to incompatible PGE. This suggests retention of primary sulphide liquid at low degrees of melting, during which PGE concentrations are little fractionated [6]. Indeed, broad positive correlations between the PGE suggest a common host, likely sulphide, observed in the samples as assemblages of pn ± po and cpy. Most fine-GAP share these patterns, indicating robustness against massive hydrous fluid influx, while Os/Ir > PUM argue against strong Os scavenging by highly oxidising hydrous fluids. Nevertheless, elevated Ru/IrPUM in a subgroup of samples may indicate a role for spinel addition under oxidising conditions. Most samples have 187Os/188Os >PUM, despite sub-PUM Re/Os, which requires addition of, or isotopic equilibration with, 187Os-rich crustal components, most likely via the precipitation of metasomatic sulphide. [1] Nimis and Morten (2000) J

An IBEM solution to the scattering of plane SH-waves by a lined tunnel in elastic wedge space

NASA Astrophysics Data System (ADS)

Liu, Zhongxian; Liu, Lei

2015-02-01

The indirect boundary element method (IBEM) is developed to solve the scattering of plane SH-waves by a lined tunnel in elastic wedge space. According to the theory of single-layer potential, the scattered-wave field can be constructed by applying virtual uniform loads on the surface of lined tunnel and the nearby wedge surface. The densities of virtual loads can be solved by establishing equations through the continuity conditions on the interface and zero-traction conditions on free surfaces. The total wave field is obtained by the superposition of free field and scattered-wave field in elastic wedge space. Numerical results indicate that the IBEM can solve the diffraction of elastic wave in elastic wedge space accurately and efficiently. The wave motion feature strongly depends on the wedge angle, the angle of incidence, incident frequency, the location of lined tunnel, and material parameters. The waves interference and amplification effect around the tunnel in wedge space is more significant, causing the dynamic stress concentration factor on rigid tunnel and the displacement amplitude of flexible tunnel up to 50.0 and 17.0, respectively, more than double that of the case of half-space. Hence, considerable attention should be paid to seismic resistant or anti-explosion design of the tunnel built on a slope or hillside.

Source characteristics and tectonic setting of mafic-ultramafic intrusions in North Xinjiang, NW China: Insights from the petrology and geochemistry of the Lubei mafic-ultramafic intrusion

NASA Astrophysics Data System (ADS)

Chen, Bao-Yun; Yu, Jin-Jie; Liu, Shuai-Jie

2018-05-01

The newly discovered Lubei sulfide-bearing mafic-ultramafic intrusion forms the western extension of the Huangshan-Jin'erquan mafic-ultramafic intrusion belt in East Tianshan, NW China. The Lubei intrusion comprises hornblende peridotite, lherzolite, and harzburgite in its southern portion, gabbro in its middle portion, and hornblende gabbro in its northern portion. Intrusive relationships indicate that three magma pulses were involved in the formation of the intrusion, and that they were likely evolved from a common primitive magma. Estimated compositions of the Lubei primitive magma are similar to those of island arc calc-alkaline basalt except for the low Na2O and CaO contents of the Lubei primitive magma. This paper reports on the mineral compositions, whole-rock major and trace element contents, and Rb-Sr and Sm-Nd isotopic compositions of the Lubei intrusion, and a zircon LA-MC-ICP-MS U-Pb age for hornblende gabbro. The Lubei intrusion is characterized by enrichment in large-ion lithophile elements, depletion in high-field-strength elements, and marked negative Nb and Ta anomalies, with enrichment in chondrite-normalized light rare earth elements. It exhibits low (87Sr/86Sr)i ratios of 0.70333-0.70636 and low (143Nd/144Nd)i ratios of 0.51214-0.51260, with positive εNd values of +4.01 to +6.33. LA-ICP-MS U-Pb zircon ages yielded a weighted-mean age of 287.9 ± 1.6 Ma for the Lubei intrusion. Contemporaneous mafic-ultramafic intrusions in different tectonic domains in North Xinjiang show similar geological and geochemical signatures to the Lubei intrusion, suggesting a source region of metasomatized mantle previously modified by hydrous fluids from the slab subducted beneath the North Xinjiang region in the early Permian. Metasomatism of the mantle was dominated by hydrous fluids and was related to subduction of the Paleo-Asian oceanic lithosphere during the Paleozoic. Sr-Nd-Pb isotopic compositions suggest that the mantle source was a mixture of depleted mid

Cultural and Personality Predictors of Facebook Intrusion: A Cross-Cultural Study.

PubMed

Błachnio, Agata; Przepiorka, Aneta; Benvenuti, Martina; Cannata, Davide; Ciobanu, Adela M; Senol-Durak, Emre; Durak, Mithat; Giannakos, Michail N; Mazzoni, Elvis; Pappas, Ilias O; Popa, Camelia; Seidman, Gwendolyn; Yu, Shu; Wu, Anise M S; Ben-Ezra, Menachem

2016-01-01

The increase in the number of users of social networking sites (SNS) has inspired intense efforts to determine intercultural differences between them. The main aim of the study was to investigate the cultural and personal predictors of Facebook intrusion. A total of 2628 Facebook users from eight countries took part in the study. The Facebook Intrusion Questionnaire, the Ten-Item Personality Inventory, and the Singelis Scale were used. We found that two variables related to Country were significantly related to Facebook intrusion: uniqueness (negatively) and low context (positively); of the personality variables, conscientiousness, and emotional stability were negatively related to the dependent variable of Facebook intrusion across different countries, which may indicate the universal pattern of Facebook intrusion. The results of the study will contribute to the international debate on the phenomenon of SNS.

On the acoustic wedge design and simulation of anechoic chamber

NASA Astrophysics Data System (ADS)

Jiang, Changyong; Zhang, Shangyu; Huang, Lixi

2016-10-01

This study proposes an alternative to the classic wedge design for anechoic chambers, which is the uniform-then-gradient, flat-wall (UGFW) structure. The working mechanisms of the proposed structure and the traditional wedge are analyzed. It is found that their absorption patterns are different. The parameters of both structures are optimized for achieving minimum absorber depth, under the condition of absorbing 99% of normal incident sound energy. It is found that, the UGFW structure achieves a smaller total depth for the cut-off frequencies ranging from 100 Hz to 250 Hz. This paper also proposes a modification for the complex source image (CSI) model for the empirical simulation of anechoic chambers, originally proposed by Bonfiglio et al. [J. Acoust. Soc. Am. 134 (1), 285-291 (2013)]. The modified CSI model considers the non-locally reactive effect of absorbers at oblique incidence, and the improvement is verified by a full, finite-element simulation of a small chamber. With the modified CSI model, the performance of both decorations with the optimized parameters in a large chamber is simulated. The simulation results are analyzed and checked against the tolerance of 1.5 dB deviation from the inverse square law, stipulated in the ISO standard 3745(2003). In terms of the total decoration depth and anechoic chamber performance, the UGFW structure is better than the classic wedge design.

Nature of the Coastal Range Wedge Along the Rupture Area of the 2015, Illapel Chile Earthquake Mw 8.4

NASA Astrophysics Data System (ADS)

Farías, M.; Comte, D.; Roecker, S. W.; Brandon, M. T.

2017-12-01

Wedge theory is usually applied to the pro-side of active subduction margins, where fold-and-thrust belts related to frontal accretion develop, but rarely to the entire wedge, where the retro-side is also relevant. We present a new 3D body wave tomographic image that combines data from the Chile-Illapel Aftershock Experiment (CHILLAX) with previous temporary seismic networks, with the aim of illuminating the nature of the wedge of the continental margin above the seismogenic part of the subducting slab. The downdip extent of the coupled part, called the S-point in the wedge theory, corresponds to the place where upper plate completely decouples from the subducting slab. This point is characterized by a Vp/Vs contrast at about 60 km depth that extends upward-and-eastward in a west-dipping ramp-like geometry. This ramp emerges about 180 km from the trench, near the topographic break related to the front of the Andean retro-side. The Coastal wedge domain is characterized by a monotonous east-dipping homocline with the older rocks of this region along the coast. The offshore region, corresponding to the pro-side, exhibits normal faulting and a very small frontal accretionary complex. Normal faulting in this region is related to rapid uplift of marine terraces since ca. 2 Ma, suggesting strong basal accretion and thus high friction on the thrust. In fact, the epicentral region of the 2015 Illapel Earthquake coincides with the highest elevations along the coast, i.e., the region with the highest slope of the margin. In this region, the lack of a continental forearc basin suggests an overlapping between the Andean and Coastal wedges. The western edge of the Andean wedge is also part of the homocline about 10 km east of the topographic boundary between both wedges, suggesting that the Coastal wedge has been deforming a part of the retro-side of the Andean wedge during the Miocene. The east-ward tilting of the retro-side was acquired mainly before the late Miocene, since at

How Wedge You Teach the Unit-Angle Concept?

ERIC Educational Resources Information Center

Millsaps, Gayle M.

2012-01-01

The concepts of angle and angle measure have been acknowledged as difficult for elementary school students to grasp (Strutchens, Martin, and Kenney 2003). The Wedge activity (Browning and Garza-Kling 2009; Van de Walle 2004; Wilson 1990) can provide an opportunity for students to examine their understanding of angle measurement and to rethink what…

Zone of intrusion study.

DOT National Transportation Integrated Search

2010-10-15

The Midwest Roadside Safety Facility (MwRSF) performed an analysis using LS-DYNA simulation to investigate the zone of intrusion (ZOI) of an NCHRP Report No. 350 2000p pickup truck when impacting a 40-in. high F-shape parapet. : The ZOI for the 40-in...

Diabetes Intrusiveness and Wellness among Elders: A Test of the Illness Intrusiveness Model

ERIC Educational Resources Information Center

DeCoster, Vaughn A.; Killian, Tim; Roessler, Richard T.

2013-01-01

Using data collected from 147 predominately African American senior citizens in Arkansas, this research examined the Illness Intrusiveness Model (Devins, 1991; Devins & Seland, 1987; Devins & Shnek, 2000) to explain variations in wellness specifically related to participants' adaptation to diabetes. The theoretical model hypothesized that…

Intrusion Detection: Generics and State-of-the-Art (la Detection de l’intrusion: Modeles generiques et etat de l’art)

DTIC Science & Technology

2002-01-01

by the user for a number of possible pre-defined intrusions. One of these pre-defined intrusions is the command “get /etc/ passwd ”. If this command is...Application-level firewalls: which check communication at the application level. An example is the string get /etc/ passwd in the ftp protocol

An Experimental Investigation of Transonic Flow Past Two-Dimensional Wedge and Circular-Arc Sections Using A Mach-Zehnder Interferometer

NASA Technical Reports Server (NTRS)

Bryson, Arthur Earl, Jr

1952-01-01

Report presents the results of interferometer measurements of the flow field near two-dimensional wedge and circular-arc sections of zero angle of attack at high-subsonic and low-supersonic velocities. Both subsonic flow with local supersonic zone and supersonic flow with detached shock wave have been investigated. Pressure distributions and drag coefficients as a function of Mach number have been obtained. The wedge data are compared with the theoretical work on flow past wedge sections of Guderley and Yoshihara, Vincenti and Wagner, and Cole. Pressure distributions and drag coefficients for the wedge and circular-arc sections are presented throughout the entire transonic range of velocities.

Origin of the Lyme Dome and implications for the timing of multiple Alleghanian deformational and intrusive events in southern Connecticut

USGS Publications Warehouse

Walsh, G.J.; Aleinikoff, J.N.; Wintsch, R.P.

2007-01-01

Geologic mapping, structural analysis, and geochronology in the area of the Lyme dome, southern Connecticut provides constraints on the origin of the rocks in the core of the dome, the absolute timing of the principal deformational and thermal events attributed to Alleghanian orogenesis, and the processes that generated the dome. Detrital zircon geochronology in combination with ages on intrusive rocks brackets the deposition of quartzite in the core of the dome sometime between ca. 925 and 620 Ma. Granite and granodiorite intruded the Neoproteorozic metasedimentary rocks in the core of the dome at ca. 620 to 610 Ma. Four major early Permian events associated with the Alleghanian orogeny affected the rocks in the Lyme dome area. Syn-tectonic migmatization and widespread penetrative deformation (D1, ca. 300 - 290 Ma) included emplacement of alaskite at 290 ?? 4 Ma during regional foliation development and aluminosilicate-orthoclase metamorphic conditions. Rocks of the Avalon terrane may have wedged between Gander cover rocks and Gander basement in the core of the Lyme during D1. Limited structural evidence for diapiric uplift of the Lyme dome indicates that diapirism started late in D1 and was completed by D2 (ca. 290 - 280 Ma) when horizontal WNW contractional stresses dominated over vertical stresses. Second sillimanite metamorphism continued and syn-tectonic D2 granite pegmatite (288 ?? 4 Ma) and the Joshua Rock Granite Gniess (284 ?? 3 Ma) intruded at this time. North-northwest extension during D3 (ca. 280 - 275 Ma) led to granitic pegmatite intrusion along S3 cleavage planes and in extensional zones in boudin necks during hydraulic failure and decompression melting. Intrusion of a Westerly Granite dike at 275 ?? 4 Ma suggests that D3 extension was active, and perhaps concluding, by ca. 275 Ma. Late randomly oriented but gently dipping pegmatite dikes record a final stage of intrusion during D4 (ca. 275 - 260 Ma), and a switch from NNW extension to vertical

Density-dependent groundwater flow and dissolution potential along a salt diapir in the Transylvanian Basin, Romania

NASA Astrophysics Data System (ADS)

Zechner, Eric; Danchiv, Alex; Dresmann, Horst; Mocuţa, Marius; Huggenberger, Peter; Scheidler, Stefan; Wiesmeier, Stefan; Popa, Iulian; Zlibut, Alexandru; Zamfirescu, Florian

2016-04-01

Salt diapirs and the surrounding sediments are often involved in a variety of human activities, such as salt mining, exploration and storage of hydrocarbons, and also storage of radioactive waste material. The presence of highly soluble evaporitic rocks, a complex tectonic setting related to salt diapirsm, and human activities can lead to significant environmental problems, e.g. land subsidence, sinkhole development, salt cavern collapse, and contamination of water resources with brines. In the Transylvanian town of Ocna Mures. rock salt of a near-surface diapir has been explored since the Roman ages in open excavations, and up to the 20th century in galleries and with solution mining. Most recently, in 2010 a sudden collapse in the adjacent Quaternary unconsolidated sediments led to the formation of a 70-90m wide salt lake with a max. depth of 23m. Over the last 3 years a Romanian-Swiss research project has led to the development of 3D geological and hydrogeological information systems in order to improve knowledge on possible hazards related to uncontrolled salt dissolution. One aspect which has been investigated is the possibility of density-driven flow along permeable subvertical zones next to the salt dome, and the potential for subsaturated groundwater to dissolve the upper sides of the diapir. Structural 3D models of the salt diapir, the adjacent basin sediments, and the mining galleries, led to the development of 2D numerical vertical density-dependent models of flow and transport along the diapir. Results show that (1) increased rock permeability due to diapirsm, regional tectonic thrusting and previous dissolution, and (2) more permeable sandstone layers within the adjacent basin sediments may lead to freshwater intrusion towards the top of the diapir, and, therefore, to increased potential for salt dissolution.

Treatment of Insertional Achilles Pathology With Dorsal Wedge Calcaneal Osteotomy in Athletes.

PubMed

Georgiannos, Dimitrios; Lampridis, Vasilis; Vasiliadis, Angelos; Bisbinas, Ilias

2017-04-01

Insertional Achilles tendinopathy and retrocalcaneal bursitis is difficult to treat, and several operative techniques have been used after failure of conservative management. Dorsal wedge calcaneal osteotomy has been described for the treatment of insertional Achilles pathology. It was hypothesized that dorsal wedge calcaneal osteotomy would be an effective and safe method for the treatment of athletes with insertional Achilles pathology unrelieved by nonoperative measures. Fifty-two athletes (64 feet) who had painful Achilles tendon syndrome unrelieved by 6 months of nonoperative measures were treated surgically. Dorsally based wedge calcaneal osteotomy was performed through a lateral approach, and 2 staples were used for fixation. Patients were scored pre- and postoperatively with the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot and Victorian Institute of Sports of Australia-Achilles (VISA-A) scores. At a minimum follow-up of 3 years, the patients' AOFAS and VISA-A scores improved from 59.5 ± 15.0 and 65.9 ± 11.1 preoperatively to 95.7 ± 6.2 and 90.2 ± 8.4 postoperatively, respectively. Clinical results were considered excellent in 38 patients, good in 12 patients, and fair in 2 patients. Return to previous sports activity time was 21 (SD, 8.0) weeks. One patient necessitated a revision operation. Operative treatment of insertional Achilles pathology in athletes with dorsal closing wedge calcaneal osteotomy was a safe and effective method that allowed for a quicker return to previous level of sports activities compared with other techniques. Level IV, retrospective case series.

Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.

PubMed

Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

2016-05-01

Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front.

Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges

PubMed Central

Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

2016-01-01

Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10−3 S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10−1 S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front. PMID:27386526

Cultural and Personality Predictors of Facebook Intrusion: A Cross-Cultural Study

PubMed Central

Błachnio, Agata; Przepiorka, Aneta; Benvenuti, Martina; Cannata, Davide; Ciobanu, Adela M.; Senol-Durak, Emre; Durak, Mithat; Giannakos, Michail N.; Mazzoni, Elvis; Pappas, Ilias O.; Popa, Camelia; Seidman, Gwendolyn; Yu, Shu; Wu, Anise M. S.; Ben-Ezra, Menachem

2016-01-01

The increase in the number of users of social networking sites (SNS) has inspired intense efforts to determine intercultural differences between them. The main aim of the study was to investigate the cultural and personal predictors of Facebook intrusion. A total of 2628 Facebook users from eight countries took part in the study. The Facebook Intrusion Questionnaire, the Ten-Item Personality Inventory, and the Singelis Scale were used. We found that two variables related to Country were significantly related to Facebook intrusion: uniqueness (negatively) and low context (positively); of the personality variables, conscientiousness, and emotional stability were negatively related to the dependent variable of Facebook intrusion across different countries, which may indicate the universal pattern of Facebook intrusion. The results of the study will contribute to the international debate on the phenomenon of SNS. PMID:27994566

Epoch of reionization window. II. Statistical methods for foreground wedge reduction

NASA Astrophysics Data System (ADS)

Liu, Adrian; Parsons, Aaron R.; Trott, Cathryn M.

2014-07-01

For there to be a successful measurement of the 21 cm epoch of reionization (EoR) power spectrum, it is crucial that strong foreground contaminants be robustly suppressed. These foregrounds come from a variety of sources (such as Galactic synchrotron emission and extragalactic point sources), but almost all share the property of being spectrally smooth and, when viewed through the chromatic response of an interferometer, occupy a signature "wedge" region in cylindrical k⊥k∥ Fourier space. The complement of the foreground wedge is termed the "EoR window" and is expected to be mostly foreground-free, allowing clean measurements of the power spectrum. This paper is a sequel to a previous paper that established a rigorous mathematical framework for describing the foreground wedge and the EoR window. Here, we use our framework to explore statistical methods by which the EoR window can be enlarged, thereby increasing the sensitivity of a power spectrum measurement. We adapt the Feldman-Kaiser-Peacock approximation (commonly used in galaxy surveys) for 21 cm cosmology and also compare the optimal quadratic estimator to simpler estimators that ignore covariances between different Fourier modes. The optimal quadratic estimator is found to suppress foregrounds by an extra factor of ˜105 in power at the peripheries of the EoR window, boosting the detection of the cosmological signal from 12σ to 50σ at the midpoint of reionization in our fiducial models. If numerical issues can be finessed, decorrelation techniques allow the EoR window to be further enlarged, enabling measurements to be made deep within the foreground wedge. These techniques do not assume that foreground is Gaussian distributed, and we additionally prove that a final round of foreground subtraction can be performed after decorrelation in a way that is guaranteed to have no cosmological signal loss.

Perturbation solutions for flow through symmetrical hoppers with inserts and asymmetrical wedge hoppers

NASA Astrophysics Data System (ADS)

Cox, G. M.; Mccue, S. W.; Thamwattana, N.; Hill, J. M.

Under certain circumstances, an industrial hopper which operates under the "funnel-flow" regime can be converted to the "mass-flow" regime with the addition of a flow-corrective insert. This paper is concerned with calculating granular flow patterns near the outlet of hoppers that incorporate a particular type of insert, the cone-in-cone insert. The flow is considered to be quasi-static, and governed by the Coulomb-Mohr yield condition together with the non-dilatant double-shearing theory. In two-dimensions, the hoppers are wedge-shaped, and as such the formulation for the wedge-in-wedge hopper also includes the case of asymmetrical hoppers. A perturbation approach, valid for high angles of internal friction, is used for both two-dimensional and axially symmetric flows, with analytic results possible for both leading order and correction terms. This perturbation scheme is compared with numerical solutions to the governing equations, and is shown to work very well for angles of internal friction in excess of 45°.

AMS Blanket and TTCS Wedge Install during EVA 32

NASA Image and Video Library

2015-10-28

Close-up view of the Alpha Magnetic Spectrometer-02 (AMS-02), in the area where the Tracker Thermal Control System (TTCS) wedge will be installed. Image was taken by Extravehicular Crewmember 2 (EV2) during Extravehicular Activity 32 (EVA 32) and released on social media.

Complex Anisotropic Structure of the Mantle Wedge Beneath Kamchatka Volcanoes

NASA Astrophysics Data System (ADS)

Levin, V.; Park, J.; Gordeev, E.; Droznin, D.

2002-12-01

A wedge of mantle material above the subducting lithospheric plate at a convergent margin is among the most dynamic environments of the Earth's interior. Deformation and transport of solid and volatile phases within this region control the fundamental process of elemental exchange between the surficial layers and the interior of the planet. A helpful property in the study of material deformation and transport within the upper mantle is seismic anisotropy, which may reflect both microscopic effects of preferentialy aligned crystals of olivine and orthopyroxene and macroscopic effects of systematic cracks, melt lenses, layering etc. Through the mapping of anisotropic properties within the mantle wedge we can establish patterns of deformation. Volatile content affects olivine alignment, so regions of anomalous volatile content may be evident. Indicators of seismic anisotropy commonly employed in upper mantle studies include shear wave birefringence and mode-conversion between compressional and shear body waves. When combined together, these techniques offer complementary constraints on the location and intensity of anisotropic properties. The eastern coast of southern Kamchatka overlies a vigorous convergent margin where the Pacific plate descends at a rate of almost 80 mm/yr towards the northwest. We extracted seismic anisotropy indicators from two data sets sensitive to the anisotropic properties of the uppermost mantle. Firstly, we evaluated teleseismic receiver functions for a number of sites, and found ample evidence for anisotropicaly-influenced P-to-S mode conversion. Secondly, we measured splitting in S waves of earthquakes with sources within the downgoing slab. The first set of observations provides constraints on the depth ranges where strong changes in anisotropic properties take place. The local splitting data provides constraints on the cumulative strength of anisotropic properties along specific pathways through the mantle wedge and possibly parts of

Cognitive avoidance of intrusive memories: recall vantage perspective and associations with depression.

PubMed

Williams, Alishia D; Moulds, Michelle L

2007-06-01

Although recent research demonstrates that intrusive memories represent an overlapping cognitive feature of depression and post-traumatic stress disorder (PTSD), there is still a general paucity of research investigating the prevalence and maintenance of intrusive memories in depression. The current study investigated the association between a range of cognitive avoidant mechanisms that characterize PTSD samples (i.e., suppression, rumination, emotional detachment, and an observer vantage perspective) and intrusive memories of negative autobiographical events in relation to dysphoria. Hypotheses were based on the proposition that employment of these cognitive mechanisms would hinder the emotional processing of the negative event, thus contributing to the maintenance of intrusions. Results supported an association between negative intrusive memories, dysphoria, and avoidant mechanisms. Significant differences were also found between field and observer memories and measures of emotional detachment and rumination. Implications relating to intrusive memory maintenance and treatment approaches are discussed.

FBX aqueous chemical dosimeter for measurement of virtual wedge profiles.

PubMed

Semwal, Manoj K; Bansal, Anil K; Thakur, Pradeep K; Vidyasagar, Pandit B

2008-10-24

We investigated the ferrous sulfate-benzoic acid-xylenol orange (FBX) aqueous chemical dosimeter for measurement of virtual (dynamic) wedge profiles on a linear accelerator. The layout for irradiation of the FBX-filled tubes mimicked a conventional linear detector array geometry. A comparison of the resulting measurements with film-measured profiles showed that, in the main beam region, the difference between the FBX system and the film system was within +/-2% and that, in the penumbra region, the difference varied from +/-1 mm to +/-2.5 mm in terms of positional equivalence, depending on the size of the dosimeter tubes. We thus believe that the energy-independent FBX dosimetry system can measure virtual wedge profiles with reasonable accuracy at reasonable cost. However, efficiency improvement is required before this dosimetry system can be accepted into routine practice.

Crossflow Instability on a Wedge-Cone at Mach 3.5

NASA Technical Reports Server (NTRS)

Beeler, George B.; Wilkinson, Stephen P.; Balakumar, P.; McDaniel, Keith S.

2012-01-01

As a follow-on activity to the HyBoLT flight experiment, a six degree half angle wedge-cone model at zero angle of attack has been employed to experimentally and computationally study the boundary layer crossflow instability at Mach 3.5 under low disturbance freestream conditions. Computed meanflow and linear stability analysis results are presented along with corresponding experimental Pitot probe data. Using a model-mounted probe survey apparatus, data acquired to date show a well defined stationary crossflow vortex pattern on the flat wedge surface. This effort paves the way for additional detailed, calibrated flow field measurements of the crossflow instability, both stationary and traveling modes, and transition-to-turbulence under quiet flow conditions as a means of validating existing stability theory and providing a foundation for dynamic flight instrumentation development.

Reconstruction of Bulk Operators within the Entanglement Wedge in Gauge-Gravity Duality

NASA Astrophysics Data System (ADS)

Dong, Xi; Harlow, Daniel; Wall, Aron C.

2016-07-01

In this Letter we prove a simple theorem in quantum information theory, which implies that bulk operators in the anti-de Sitter/conformal field theory (AdS/CFT) correspondence can be reconstructed as CFT operators in a spatial subregion A , provided that they lie in its entanglement wedge. This is an improvement on existing reconstruction methods, which have at most succeeded in the smaller causal wedge. The proof is a combination of the recent work of Jafferis, Lewkowycz, Maldacena, and Suh on the quantum relative entropy of a CFT subregion with earlier ideas interpreting the correspondence as a quantum error correcting code.

Reconstruction of Bulk Operators within the Entanglement Wedge in Gauge-Gravity Duality.

PubMed

Dong, Xi; Harlow, Daniel; Wall, Aron C

2016-07-08

In this Letter we prove a simple theorem in quantum information theory, which implies that bulk operators in the anti-de Sitter/conformal field theory (AdS/CFT) correspondence can be reconstructed as CFT operators in a spatial subregion A, provided that they lie in its entanglement wedge. This is an improvement on existing reconstruction methods, which have at most succeeded in the smaller causal wedge. The proof is a combination of the recent work of Jafferis, Lewkowycz, Maldacena, and Suh on the quantum relative entropy of a CFT subregion with earlier ideas interpreting the correspondence as a quantum error correcting code.

Monoplanar versus biplanar medial open-wedge proximal tibial osteotomy for varus gonarthrosis: a comparison of clinical and radiological outcomes.

PubMed

Elmalı, Nurzat; Esenkaya, Irfan; Can, Murat; Karakaplan, Mustafa

2013-12-01

We compared clinical and radiological results of two proximal tibial osteotomy (PTO) techniques: monoplanar medial open-wedge osteotomy and biplanar retrotubercle medial open-wedge osteotomy, stabilised by a wedged plate. We evaluated 88 knees in 78 patients. Monoplanar medial open-wedge PTO was performed on 56 knees in 50 patients with a mean age of 55 ± 9 years. Biplanar retrotubercle medial open-wedge PTO was performed on 32 knees in 28 patients with a mean age of 57 ± 7 years. Mean follow-up periods were 40.6 ± 7 months for the monoplanar PTO group and 38 ± 5 months for the biplanar retrotubercle PTO group. Clinical outcome was evaluated using the hospital for special surgery scoring system, and radiological outcome was evaluated by the measurements of femorotibial angle (FTA), patellar height and tibial slope changes. In both groups, post-operative HSS scores increased significantly. No significant difference was found between groups in FTA alteration, but the FTA decreased significantly in both groups. Patellar index ratios decreased significantly in the monoplanar PTO group (Insall-Salvati Index by 0.07, Blackburne-Peel Index by 0.07), but not in the biplanar retrotubercle PTO group. Tibial slopes were increased significantly in the monoplanar PTO group, but not in the retrotubercle PTO group. Biplanar retrotubercle medial open-wedge osteotomy and monoplanar medial open-wedge osteotomy are both clinically effective for the treatment for varus gonarthrosis. Retrotubercle osteotomy also prevents patella infera and tibial slope changes radiologically.

Scanning Seismic Intrusion Detector

NASA Technical Reports Server (NTRS)

Lee, R. D.

1982-01-01

Scanning seismic intrusion detector employs array of automatically or manually scanned sensors to determine approximate location of intruder. Automatic-scanning feature enables one operator to tend system of many sensors. Typical sensors used with new system are moving-coil seismic pickups. Detector finds uses in industrial security systems.

Analytical solutions for two-dimensional Stokes flow singularities in a no-slip wedge of arbitrary angle

PubMed Central

Brzezicki, Samuel J.

2017-01-01

An analytical method to find the flow generated by the basic singularities of Stokes flow in a wedge of arbitrary angle is presented. Specifically, we solve a biharmonic equation for the stream function of the flow generated by a point stresslet singularity and satisfying no-slip boundary conditions on the two walls of the wedge. The method, which is readily adapted to any other singularity type, takes full account of any transcendental singularities arising at the corner of the wedge. The approach is also applicable to problems of plane strain/stress of an elastic solid where the biharmonic equation also governs the Airy stress function. PMID:28690412

Analytical solutions for two-dimensional Stokes flow singularities in a no-slip wedge of arbitrary angle.

PubMed

Crowdy, Darren G; Brzezicki, Samuel J

2017-06-01

An analytical method to find the flow generated by the basic singularities of Stokes flow in a wedge of arbitrary angle is presented. Specifically, we solve a biharmonic equation for the stream function of the flow generated by a point stresslet singularity and satisfying no-slip boundary conditions on the two walls of the wedge. The method, which is readily adapted to any other singularity type, takes full account of any transcendental singularities arising at the corner of the wedge. The approach is also applicable to problems of plane strain/stress of an elastic solid where the biharmonic equation also governs the Airy stress function.

The importance of mantle wedge heterogeneity to subduction zone magmatism and the origin of EM1

NASA Astrophysics Data System (ADS)

Turner, Stephen J.; Langmuir, Charles H.; Dungan, Michael A.; Escrig, Stephane

2017-08-01

The composition of the convecting asthenospheric mantle that feeds the mantle wedge can be investigated via rear-arc lavas that have minimal slab influence. This "ambient mantle wedge" composition (the composition of the wedge prior to the addition of a slab component) varies substantially both worldwide and within individual arcs. 143Nd/144Nd measurements of rear-arc samples that have minimal slab influence are similar to 143Nd/144Nd in the stratovolcanoes of the adjacent volcanic fronts, suggesting that 143Nd/144Nd of arc-front volcanics are largely inherited from the ambient mantle composition. 143Nd/144Nd correlates with ratios such as Th/U, Zr/Nb, and La/Sm, indicating that these ratios also are strongly influenced by ambient wedge heterogeneity. The same phenomenon is observed among individual volcanoes from the Chilean Southern Volcanic Zone (SVZ), where along-strike variability of the volcanic front tracks that of rear-arc monogenetic volcanics. Depleted mantle wedges are more strongly influenced by slab-derived components than are enriched wedges. This leads to surprising trace element correlations in the global dataset, such as between Pb/Nb and Zr/Nb, which are not explicable by variable compositions or fluxes of slab components. Depleted ambient mantle is present beneath arcs with back-arc spreading; relatively enriched mantle is present adjacent to continents. Ambient mantle wedge heterogeneity both globally and regionally forms isotope mixing trajectories for Sr, Nd and Hf between depleted mantle and EM1-type enriched compositions as represented by Gough Island basalts. Making use of this relationship permits a quantitative match with the SVZ data. It has been suggested that EM1-type mantle reservoirs are the result of recycled lower continental crust, though such models do not account for certain trace element ratios such as Ce/Pb and Nb/U or the surprisingly homogeneous trace element compositions of EM1 volcanics. A model in which the EM1 end

40 CFR 197.26 - What are the circumstances of the human intrusion?

Code of Federal Regulations, 2010 CFR

2010-07-01

... human intrusion? 197.26 Section 197.26 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... YUCCA MOUNTAIN, NEVADA Public Health and Environmental Standards for Disposal Human-Intrusion Standard § 197.26 What are the circumstances of the human intrusion? For the purposes of the analysis of human...

Intrusion detection using rough set classification.

PubMed

Zhang, Lian-hua; Zhang, Guan-hua; Zhang, Jie; Bai, Ying-cai

2004-09-01

Recently machine learning-based intrusion detection approaches have been subjected to extensive researches because they can detect both misuse and anomaly. In this paper, rough set classification (RSC), a modern learning algorithm, is used to rank the features extracted for detecting intrusions and generate intrusion detection models. Feature ranking is a very critical step when building the model. RSC performs feature ranking before generating rules, and converts the feature ranking to minimal hitting set problem addressed by using genetic algorithm (GA). This is done in classical approaches using Support Vector Machine (SVM) by executing many iterations, each of which removes one useless feature. Compared with those methods, our method can avoid many iterations. In addition, a hybrid genetic algorithm is proposed to increase the convergence speed and decrease the training time of RSC. The models generated by RSC take the form of "IF-THEN" rules, which have the advantage of explication. Tests and comparison of RSC with SVM on DARPA benchmark data showed that for Probe and DoS attacks both RSC and SVM yielded highly accurate results (greater than 99% accuracy on testing set).

Non-intrusive refrigerant charge indicator

DOEpatents

Mei, Viung C.; Chen, Fang C.; Kweller, Esher

2005-03-22

A non-intrusive refrigerant charge level indicator includes a structure for measuring at least one temperature at an outside surface of a two-phase refrigerant line section. The measured temperature can be used to determine the refrigerant charge status of an HVAC system, and can be converted to a pressure of the refrigerant in the line section and compared to a recommended pressure range to determine whether the system is under-charged, properly charged or over-charged. A non-intrusive method for assessing the refrigerant charge level in a system containing a refrigerant fluid includes the step of measuring a temperature at least one outside surface of a two-phase region of a refrigerant containing refrigerant line, wherein the temperature measured can be converted to a refrigerant pressure within the line section.

Observed assertive and intrusive maternal feeding behaviors increase child adiposity123

PubMed Central

Ozbeki, Tina N; Appugliese, Danielle P; Kaciroti, Niko; Corwyn, Robert F; Bradley, Robert H

2012-01-01

Background: Few studies have examined observed maternal feeding behaviors and their potential association with child adiposity. The association between maternal prompting to eat and child adiposity has been inconsistent. Objectives: This study sought to identify factors associated with maternal feeding behaviors and to test the hypothesis that more maternal prompts to eat, more assertive prompts, and more intrusiveness are associated with greater child adiposity. Design: Children (n = 1218) and their mothers were videotaped eating a standardized snack at ages 15, 24, and 36 mo. Maternal prompts to eat, the percentage of prompts that were assertive, and intrusiveness were coded. Adjusted regression analyses evaluated predictors of prompts, the percentage of assertive prompts, and intrusiveness and the relation of each of these factors with child adiposity (weight-for-length z score at 15 mo and BMI z score at 24 and 36 mo) after control for the child's race-ethnicity and sex, family income-to-needs ratio, and maternal education, weight status, and depressive symptoms. Results: At 36 mo, mothers gave an average of 9.3 prompts; 61% of prompts were assertive, and 48% of mothers were intrusive. Lower maternal education and minority race-ethnicity were associated with a greater percentage of assertive prompts and intrusiveness. A greater percentage of assertive prompts and intrusiveness, but not total prompts, was associated with higher child adiposity. Conclusions: Assertive prompting and an intrusive style had small but significant associations with greater child adiposity. Future work should focus on maternal motivations for assertive and intrusive feeding styles and mechanisms through which these feeding styles might increase child adiposity. PMID:22277552

RANS Analyses of Turbofan Nozzles with Wedge Deflectors for Noise Reduction

NASA Technical Reports Server (NTRS)

DeBonis, James R.

2008-01-01

Computational fluid dynamics (CFD) was used to evaluate a promising concept for reducing the noise at take-off of dual-stream, turbofan nozzles. The concept, offset stream technology, reduces the jet noise observed on the ground by diverting (offsetting) the majority of the fan flow below the core flow, thickening this layer between the high velocity core flow and the ground observers. In this study a wedge placed in the internal fan stream is used as the diverter. Wind, a Reynolds Averaged Navier-Stokes (RANS) code, was used to analyze the flowfield of the exhaust plume and to calculate nozzle performance. Results showed that the wedge effectively diverts the fan flow and the turbulent kinetic energy on the observer side of the nozzle is reduced. The reduction in turbulent kinetic energy should correspond to a reduction in noise. The blockage due to the wedge reduces the fan massflow proportional to its blockage and the overall thrust is consequently reduced. The CFD predictions are in very good agreement with experimental data. This noise reduction concept shows promise for reduced jet noise at a small reduction in thrust. It has been demonstrated that RANS CFD can be used to optimize this concept.

Simulating the influence of groundwater table fluctuation on vapor intrusion

NASA Astrophysics Data System (ADS)

Huo, J.

2017-12-01

The migration of volatile chemicals from groundwater to an overlying building is a commonly existing phenomenon around the world. Due to the distinction of hydrologic conditions among vapor intrusion sites, it is necessary to consider the effect of dominant hydrologic factors in order to obtain a precise site evaluation and a health risk assessment during the screening process. This study mainly discusses the impact of groundwater table fluctuation and other hydrological factors including porosity, permeability and soil moisture on the vapor intrusion transport. A two-dimensional model is configured to inject different typical volatile organic contaminants from EPA's Vapor Intrusion Database. Through quantifying the contaminant vapor concentration attenuation factors under the effect of groundwater table fluctuation, this study provides suggestions for indoor air sample and vapor intrusion assessment.

First metatarsal closing base wedge osteotomy using real-time fluoroscopy.

PubMed

Toepp, F C; Salcedo, M

1991-01-01

A minimal incision surgery approach to metatarsus primus adductus is presented. The percutaneous closing base wedge osteotomy is performed using real-time intraoperative fluoroscopy. The advantages and disadvantages of this minimal incision surgical procedure are discussed.

Semianalytical solutions for contaminant transport under variable velocity field in a coastal aquifer

NASA Astrophysics Data System (ADS)

Koohbor, Behshad; Fahs, Marwan; Ataie-Ashtiani, Behzad; Simmons, Craig T.; Younes, Anis

2018-05-01

Existing closed-form solutions of contaminant transport problems are limited by the mathematically convenient assumption of uniform flow. These solutions cannot be used to investigate contaminant transport in coastal aquifers where seawater intrusion induces a variable velocity field. An adaptation of the Fourier-Galerkin method is introduced to obtain semi-analytical solutions for contaminant transport in a confined coastal aquifer in which the saltwater wedge is in equilibrium with a freshwater discharge flow. Two scenarios dealing with contaminant leakage from the aquifer top surface and contaminant migration from a source at the landward boundary are considered. Robust implementation of the Fourier-Galerkin method is developed to efficiently solve the coupled flow, salt and contaminant transport equations. Various illustrative examples are generated and the semi-analytical solutions are compared against an in-house numerical code. The Fourier series are used to evaluate relevant metrics characterizing contaminant transport such as the discharge flux to the sea, amount of contaminant persisting in the groundwater and solute flux from the source. These metrics represent quantitative data for numerical code validation and are relevant to understand the effect of seawater intrusion on contaminant transport. It is observed that, for the surface contamination scenario, seawater intrusion limits the spread of the contaminant but intensifies the contaminant discharge to the sea. For the landward contamination scenario, moderate seawater intrusion affects only the spatial distribution of the contaminant plume while extreme seawater intrusion can increase the contaminant discharge to the sea. The developed semi-analytical solution presents an efficient tool for the verification of numerical models. It provides a clear interpretation of the contaminant transport processes in coastal aquifers subject to seawater intrusion. For practical usage in further studies, the full

Application of a Hidden Bayes Naive Multiclass Classifier in Network Intrusion Detection

ERIC Educational Resources Information Center

Koc, Levent

2013-01-01

With increasing Internet connectivity and traffic volume, recent intrusion incidents have reemphasized the importance of network intrusion detection systems for combating increasingly sophisticated network attacks. Techniques such as pattern recognition and the data mining of network events are often used by intrusion detection systems to classify…

Mass stranding of wedge-tailed shearwater chicks in Hawaii

USGS Publications Warehouse

Work, Thierry M.; Rameyer, Robert

1999-01-01

Unusual numbers of wedge-tailed shearwater (Puffinus pacificus) chicks stranded on Oahu (Hawaii, USA) in 1994. Compared to healthy wedge-tailed shearwater (WTSW) chicks, stranded chicks were underweight, dehydrated, leukopenic, lymphopenic, eosinopenic, and heterophilic; some birds were toxemic and septic. Stranded chicks also were hypoglycemic and had elevated aspartate amino transferase levels. Most chicks apparently died from emaciation, dehydration, or bacteremia. Because many birds with bacteremia also had severe necrosis of the gastrointestinal (GI) mucosa associated with bacteria, we suspect the GI tract to be the source of disseminated bacterial infection. The identity of the bacteria was not confirmed. The daily number of chicks stranded was significantly related to average wind speeds, and the mortality coincided with the fledging period for WTSW. Strong southeasterly winds were a distinguishing meteorologic factor in 1994 and contributed to the distribution of stranded chicks on Oahu. More objective data on WTSW demographics would enhance future efforts to determine predisposing causes of WTSW wrecks and their effects on seabird colonies.

An automated optical wedge calibrator for Dobson ozone spectrophotometers

NASA Technical Reports Server (NTRS)

Evans, R. D.; Komhyr, W. D.; Grass, R. D.

1994-01-01

The Dobson ozone spectrophotometer measures the difference of intensity between selected wavelengths in the ultraviolet. The method uses an optical attenuator (the 'Wedge') in this measurement. The knowledge of the relationship of the wedge position to the attenuation is critical to the correct calculation of ozone from the measurement. The procedure to determine this relationship is time-consuming, and requires a highly skilled person to perform it correctly. The relationship has been found to change with time. For reliable ozone values, the procedure should be done on a Dobson instrument at regular intervals. Due to the skill and time necessary to perform this procedure, many instruments have gone as long as 15 years between procedures. This article describes an apparatus that performs the procedure under computer control, and is adaptable to the majority of existing Dobson instruments. Part of the apparatus is usable for normal operation of the Dobson instrument, and would allow computer collection of the data and real-time ozone measurements.

Intensively exploited Mediterranean aquifers: resilience to seawater intrusion and proximity to critical thresholds

NASA Astrophysics Data System (ADS)

Mazi, K.; Koussis, A. D.; Destouni, G.

2014-05-01

We investigate seawater intrusion in three prominent Mediterranean aquifers that are subject to intensive exploitation and modified hydrologic regimes by human activities: the Nile Delta, Israel Coastal and Cyprus Akrotiri aquifers. Using a generalized analytical sharp interface model, we review the salinization history and current status of these aquifers, and quantify their resilience/vulnerability to current and future seawater intrusion forcings. We identify two different critical limits of seawater intrusion under groundwater exploitation and/or climatic stress: a limit of well intrusion, at which intruded seawater reaches key locations of groundwater pumping, and a tipping point of complete seawater intrusion up to the prevailing groundwater divide of a coastal aquifer. Either limit can be reached, and ultimately crossed, under intensive aquifer exploitation and/or climate-driven change. We show that seawater intrusion vulnerability for different aquifer cases can be directly compared in terms of normalized intrusion performance curves. The site-specific assessments show that (a) the intruding seawater currently seriously threatens the Nile Delta aquifer, (b) in the Israel Coastal aquifer the sharp interface toe approaches the well location and (c) the Cyprus Akrotiri aquifer is currently somewhat less threatened by increased seawater intrusion.

Intensively exploited Mediterranean aquifers: resilience and proximity to critical points of seawater intrusion

NASA Astrophysics Data System (ADS)

Mazi, K.; Koussis, A. D.; Destouni, G.

2013-11-01

We investigate here seawater intrusion in three prominent Mediterranean aquifers that are subject to intensive exploitation and modified hydrologic regimes by human activities: the Nile Delta Aquifer, the Israel Coastal Aquifer and the Cyprus Akrotiri Aquifer. Using a generalized analytical sharp-interface model, we review the salinization history and current status of these aquifers, and quantify their resilience/vulnerability to current and future sea intrusion forcings. We identify two different critical limits of sea intrusion under groundwater exploitation and/or climatic stress: a limit of well intrusion, at which intruded seawater reaches key locations of groundwater pumping, and a tipping point of complete sea intrusion upto the prevailing groundwater divide of a coastal aquifer. Either limit can be reached, and ultimately crossed, under intensive aquifer exploitation and/or climate-driven change. We show that sea intrusion vulnerability for different aquifer cases can be directly compared in terms of normalized intrusion performance curves. The site-specific assessments show that the advance of seawater currently seriously threatens the Nile Delta Aquifer and the Israel Coastal Aquifer. The Cyprus Akrotiri Aquifer is currently somewhat less threatened by increased seawater intrusion.

Associations between intrusive thoughts, reality discrimination and hallucination-proneness in healthy young adults.

PubMed

Smailes, David; Meins, Elizabeth; Fernyhough, Charles

2015-01-01

People who experience intrusive thoughts are at increased risk of developing hallucinatory experiences, as are people who have weak reality discrimination skills. No study has yet examined whether these two factors interact to make a person especially prone to hallucinatory experiences. The present study examined this question in a non-clinical sample. Participants were 160 students, who completed a reality discrimination task, as well as self-report measures of cannabis use, negative affect, intrusive thoughts and auditory hallucination-proneness. The possibility of an interaction between reality discrimination performance and level of intrusive thoughts was assessed using multiple regression. The number of reality discrimination errors and level of intrusive thoughts were independent predictors of hallucination-proneness. The reality discrimination errors × intrusive thoughts interaction term was significant, with participants who made many reality discrimination errors and reported high levels of intrusive thoughts being especially prone to hallucinatory experiences. Hallucinatory experiences are more likely to occur in people who report high levels of intrusive thoughts and have weak reality discrimination skills. If applicable to clinical samples, these findings suggest that improving patients' reality discrimination skills and reducing the number of intrusive thoughts they experience may reduce the frequency of hallucinatory experiences.

Distributed intrusion detection system based on grid security model

NASA Astrophysics Data System (ADS)

Su, Jie; Liu, Yahui

2008-03-01

Grid computing has developed rapidly with the development of network technology and it can solve the problem of large-scale complex computing by sharing large-scale computing resource. In grid environment, we can realize a distributed and load balance intrusion detection system. This paper first discusses the security mechanism in grid computing and the function of PKI/CA in the grid security system, then gives the application of grid computing character in the distributed intrusion detection system (IDS) based on Artificial Immune System. Finally, it gives a distributed intrusion detection system based on grid security system that can reduce the processing delay and assure the detection rates.

Cementless Tapered Wedge Femoral Stems Decrease Subsidence in Obese Patients Compared to Traditional Fit-and-Fill Stems.

PubMed

Grant, Tanner W; Lovro, Luke R; Licini, David J; Warth, Lucian C; Ziemba-Davis, Mary; Meneghini, Robert M

2017-03-01

Femoral component stability and resistance to subsidence is critical for osseointegration and clinical success in cementless total hip arthroplasty. The purpose of this study was to radiographically evaluate the anatomic fit and subsidence of 2 different proximally tapered, porous-coated modern cementless femoral component designs. A retrospective cohort study of 126 consecutive cementless total hip arthroplasties was performed. Traditional fit-and-fill stems were implanted in the first 61 hips with the remaining 65 receiving morphometric tapered wedge stems. Preoperative bone morphology was radiographically assessed by the canal flare index. Canal fill in the coronal plane, subsidence, and the sagittal alignment of stems was measured digitally on immediate and 1-month postoperative radiographs. Demographics and canal flare indices were similar between groups. The percentage of femoral canal fill was greater in the tapered wedge compared to the fit-and-fill stem (P = .001). There was significantly less subsidence in the tapered wedge design (0.3 mm) compared to the fit-and-fill design (1.1 mm) (P = .001). Subsidence significantly increased as body mass index (BMI) increased in the fit-and-fill stems, a finding not observed in the tapered wedge design (P = .013). An anatomically designed morphometric tapered wedge femoral stem demonstrated greater axial stability and decreased subsidence with increasing BMI than a traditional fit-and-fill stem. The resistance to subsidence, irrespective of BMI, is likely due to the inherent axial stability of a tapered wedge design and may be the optimal stem design for obese patients. Copyright © 2016 Elsevier Inc. All rights reserved.

The importance of context: evidence that contextual representations increase intrusive memories.

PubMed

Pearson, David G; Ross, Fiona D C; Webster, Victoria L

2012-03-01

Intrusive memories appear to enter consciousness via involuntary rather than deliberate recollection. Some clinical accounts of PTSD seek to explain this phenomenon by making a clear distinction between the encoding of sensory-based and contextual representations. Contextual representations have been claimed to actively reduce intrusions by anchoring encoded perceptual data for an event in memory. The current analogue trauma study examined this hypothesis by manipulating contextual information independently from encoded sensory-perceptual information. Participants' viewed images selected from the International Affective Picture System that depicted scenes of violence and bodily injury. Images were viewed either under neutral conditions or paired with contextual information. Two experiments revealed a significant increase in memory intrusions for images paired with contextual information in comparison to the same images viewed under neutral conditions. In contrast to the observed increase in intrusion frequency there was no effect of contextual representations on voluntary memory for the images. The vividness and emotionality of memory intrusions were also unaffected. The analogue trauma paradigm may fail to replicate the effect of extreme stress on encoding postulated to occur during PTSD. These findings question the assertion that intrusive memories develop from a lack of integration between sensory-based and contextual representations in memory. Instead it is argued contextual representations play a causal role in increasing the frequency of intrusions by increasing the sensitivity of memory to involuntary retrieval by associated internal and external cues. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hazard Models From Periodic Dike Intrusions at Kı¯lauea Volcano, Hawai`i

NASA Astrophysics Data System (ADS)

Montgomery-Brown, E. K.; Miklius, A.

2016-12-01

The persistence and regular recurrence intervals of dike intrusions in the East Rift Zone (ERZ) of Kı¯lauea Volcano lead to the possibility of constructing a time-dependent intrusion hazard model. Dike intrusions are commonly observed in Kı¯lauea Volcano's ERZ and can occur repeatedly in regions that correlate with seismic segments (sections of rift seismicity with persistent definitive lateral boundaries) proposed by Wright and Klein (USGS PP1806, 2014). Five such ERZ intrusions have occurred since 1983 with inferred locations downrift of the bend in Kı¯lauea's ERZ, with the first (1983) being the start of the ongoing ERZ eruption. The ERZ intrusions occur on one of two segments that are spatially coincident with seismic segments: Makaopuhi (1993 and 2007) and Nāpau (1983, 1997, and 2011). During each intrusion, the amount of inferred dike opening was between 2 and 3 meters. The times between ERZ intrusions for same-segment pairs are all close to 14 years: 14.07 (1983-1997), 14.09 (1997-2011), and 13.95 (1993-2007) years, with the Nāpau segment becoming active about 3.5 years after the Makaopuhi segment in each case. Four additional upper ERZ intrusions are also considered here. Dikes in the upper ERZ have much smaller opening ( 10 cm), and have shorter recurrence intervals of 8 years with more variability. The amount of modeled dike opening during each of these events roughly corresponds to the amount of seaward south flank motion and deep rift opening accumulated in the time between events. Additionally, the recurrence interval of 14 years appears to be unaffected by the magma surge of 2003-2007, suggesting that flank motion, rather than magma supply, could be a controlling factor in the timing and periodicity of intrusions. Flank control over the timing of magma intrusions runs counter to the historical research suggesting that dike intrusions at Kı¯lauea are driven by magma overpressure. This relatively free sliding may have resulted from decreased

The effect of foot orthoses and in-shoe wedges during cycling: a systematic review

PubMed Central

2014-01-01

Background The use of foot orthoses and in-shoe wedges in cycling are largely based on theoretical benefits and anecdotal evidence. This review aimed to systematically collect all published research on this topic, critically evaluate the methods and summarise the findings. Methods Study inclusion criteria were: all empirical studies that evaluated the effects of foot orthoses or in-shoe wedges on cycling; outcome measures that investigated physiological parameters, kinematics and kinetics of the lower limb, and power; and, published in English. Studies were located by data-base searching (Medline, CINAHL, Embase and SPORTDiscus) and hand-searching in February 2014. Selected studies were assessed for methodological quality using a modified Quality Index. Data were synthesised descriptively. Meta-analysis was not performed as the included studies were not sufficiently homogeneous to provide a meaningful summary. Results Six studies were identified as meeting the eligibility criteria. All studies were laboratory-based and used a repeated measures design. The quality of the studies varied, with Quality Index scores ranging from 7 to 10 out of 14. Five studies investigated foot orthoses and one studied in-shoe wedges. Foot orthoses were found to increase contact area in the midfoot, peak pressures under the hallux and were perceived to provide better arch support, compared to a control. With respect to physiological parameters, contrasting findings have been reported regarding the effect foot orthoses have on oxygen consumption. Further, foot orthoses have been shown to not provide effects on lower limb kinematics and perceived comfort. Both foot orthoses and in-shoe wedges have been shown to provide no effect on power. Conclusion In general, there is limited high-quality research on the effects foot orthoses and in-shoe wedges provide during cycling. At present, there is some evidence that during cycling foot orthoses: increase contact area under the foot and increase

Structural deformation and detailed architecture of accretionary wedge in the northern Manila subduction zone

NASA Astrophysics Data System (ADS)

Gao, J.; Wu, S.; Yao, Y.; Chen, C.

2017-12-01

The South China Sea (SCS) which located at the southeast edge of the Eurasian plate, is heavily influenced by the Philippine Sea plate and the Indo-Australian plate. As eastern boundary of the SCS, Manila subduction zone was created by the northwestern movement of the Philippine Sea plate, recorded the key information on formation and evolution of the SCS and often triggered off earthquakes and tsunami in the East and South Asia. Using high resolution multi-channel seismic data across the northern Manila subduction zone, this study analyzed sedimentary characteristics of oceanic basin and trench, and fine described features of structural deformation and architecture of accretionary wedge and magmatism to discuss the time of subduction inception, thrust motion and influence of seamount subduction on the geometry of the Manila trench. Results show that lower slope of accretionary wedge mainly consist of imbricated thrusts with blind thrust as the frontal fault and structural wedge whereas upper slope was obscure for intensely structural deformation and magmatism. All the thrust faults merged into a detachment fault/surface which may root in Lower Miocene or even older strata, cut off the Miocene near buried seamount and extended the Pliocene upward, suggesting that this detachment fault was obviously influenced by buried seamount and basement high below the accretionary wedge. Magmatism began to be active from late Miocene and continued to be intense during Pliocene and Quaternary in the oceanic basin, trench and accretionary wedge. Based on characteristics of sedimentary and structural deformation, this study proposed that accretionary wedge of the northern Manila subduction zone formed before 16.5 Ma and propagated to the SCS through piggyback propagation thrusting when seafloor spreading of the SCS was still ongoing before 15 Ma. Subduction of extended continental crust in the northeastern SCS created a significantly concaving eastward to geometric shape of the

Work zone intrusion alarm effectiveness.

DOT National Transportation Integrated Search

2010-09-01

16. Abstract : The New Jersey Department of Transportation (NJDOT) commissioned a study to evaluate how : effective a work zone safety device known as the SonoBlaster! Work Zone Intrusion Alarm would be : in protecting maintenance workers fro...

Kinematic segmentation of accretive wedges based on scaled sandbox experiments and their application to nature

NASA Astrophysics Data System (ADS)

Lohrmann, J.; Kukowski, N.; Oncken, O.

2003-04-01

Recording the incremental displacement field of scaled analogue simulations provides detailed data on wedge kinematics and timing of internal deformation. This is a very efficient tool to develop kinematic concepts and test mechanical theories, e.g. the critical-taper theory. Such models could not be validated until now by the available geological and geophysical data, since there was no information about the incremental displacement field. Recent GPS measurements and seismological investigations at convergent margins provide well-constrained strain-rates and kinematics of short-termed processes. These data allow the kinematic models that are based on analogue simulations to be tested against field observations. We investigate convergent accretive sand wedges in scaled analogue simulations. We define three kinematic segments based on distinctive wedge taper, displacement field and timing of deformation (recorded at a slow sampling rate, which represents the geological scale). Only one of these segments is in a critical state of stress, whereas the other segments are either in a sub-critical or stable state of stress. Such a kinematic segmentation is not predicted for ideally homogeneous wedge-shaped bodies by the critical-taper theory, but can be explained by the formation of localised weak shear zones, which preferentially accommodate deformation. These weak zones are formed in granular analogue materials, and also in natural rocks, since these materials show a strain-softening phase prior to the achievement of stable mechanical conditions. Therefore we suggest that the kinematic segmentation of convergent sand wedges should also be observed in natural settings, such as accretionary wedges, foreland fold-and-thrust belts and even entire orogens. To validate this hypothesis we compare strain rates from GPS measurements and kinematics deduced from focal mechanisms with the respective data from sandbox experiments. We present a strategy to compare strain rates and

Analog modeling of the deformation and kinematics of the Calabrian accretionary wedge

NASA Astrophysics Data System (ADS)

Dellong, David; Gutscher, Marc-Andre; Klingelhoefer, Frauke; Graindorge, David; Kopp, Heidrun; Mercier de Lepinay, Bernard; Dominguez, Stephane; Malavieille, Jacques

2017-04-01

The Calabrian accretionary wedge in the Ionian Sea, is the site of slow, deformation related to the overall convergence between Africa and Eurasia and the subduction zone beneath Calabria. High-resolution swath bathymetric data and seismic profiling image a complex network of compressional and strike-slip structures. Major Mesozoic rift structures (Malta Escarpment) are also present and appear to be reactivated in places by normal faulting. Ongoing normal faulting also occurs in the straits of Messina area (1908 M7.2 earthquake). We applied analog modeling using granular materials as well as ductile (silicone) in some experiments. The objective was to test the predictions of certain kinematic models regarding the location and kinematics of a major lateral slab edge tear fault. One experiment, using two independently moving backstops, demonstrates that the relative kinematics of the Calabrian and Peloritan blocks can produce a zone of dextral transtension and subsidence which corresponds well to the asymmetric rift observed in seismic data in the southward prolongation of the straits of Messina faults. However, the expected dextral offset in the deformation front of the accretionary wedge is not observed in bathymetry. In fact sinistral motion is observed along the boundary between two lobes of the accretionary wedge suggesting the dextral motion is absorbed along a network of transcurrent faults within the eastern lobe. Bathymetric and seismic observations indicate that the major dextral boundary along the western boundary of the accretionary wedge is the Alfeo fault system, whose southern termination is the focal point of a striking set of radial slip-lines. Further analog modeling experiments attempted to reproduce these structures, with mixed results.

Dike intrusions during rifting episodes obey scaling relationships similar to earthquakes.

PubMed

Passarelli, L; Rivalta, E; Shuler, A

2014-01-28

As continental rifts evolve towards mid-ocean ridges, strain is accommodated by repeated episodes of faulting and magmatism. Discrete rifting episodes have been observed along two subaerial divergent plate boundaries, the Krafla segment of the Northern Volcanic Rift Zone in Iceland and the Manda-Hararo segment of the Red Sea Rift in Ethiopia. In both cases, the initial and largest dike intrusion was followed by a series of smaller intrusions. By performing a statistical analysis of these rifting episodes, we demonstrate that dike intrusions obey scaling relationships similar to earthquakes. We find that the dimensions of dike intrusions obey a power law analogous to the Gutenberg-Richter relation, and the long-term release of geodetic moment is governed by a relationship consistent with the Omori law. Due to the effects of magma supply, the timing of secondary dike intrusions differs from that of the aftershocks. This work provides evidence of self-similarity in the rifting process.

Tell me more: Can a memory test reduce analogue traumatic intrusions?

PubMed

Krans, Julie; Näring, Gérard; Holmes, Emily A; Becker, Eni S

2009-05-01

Information processing theories of post-traumatic stress disorder (PTSD) state that intrusive images emerge due to a lack of integration of perceptual trauma representations in autobiographical memory. To test this hypothesis experimentally, participants were shown an aversive film to elicit intrusive images. After viewing, they received a recognition test for just one part of the film. The test contained neutrally formulated items to rehearse information from the film. Participants reported intrusive images for the film in an intrusion diary during one week after viewing. In line with expectations, the number of intrusive images decreased only for the part of the film for which the recognition test was given. Furthermore, deliberate cued-recall memory after one week was selectively enhanced for the film part that was in the recognition test a week before. The findings provide new evidence supporting information processing models of PTSD and have potential implications for early interventions after trauma.

Dike intrusions during rifting episodes obey scaling relationships similar to earthquakes

PubMed Central

L., Passarelli; E., Rivalta; A., Shuler

2014-01-01

As continental rifts evolve towards mid-ocean ridges, strain is accommodated by repeated episodes of faulting and magmatism. Discrete rifting episodes have been observed along two subaerial divergent plate boundaries, the Krafla segment of the Northern Volcanic Rift Zone in Iceland and the Manda-Hararo segment of the Red Sea Rift in Ethiopia. In both cases, the initial and largest dike intrusion was followed by a series of smaller intrusions. By performing a statistical analysis of these rifting episodes, we demonstrate that dike intrusions obey scaling relationships similar to earthquakes. We find that the dimensions of dike intrusions obey a power law analogous to the Gutenberg-Richter relation, and the long-term release of geodetic moment is governed by a relationship consistent with the Omori law. Due to the effects of magma supply, the timing of secondary dike intrusions differs from that of the aftershocks. This work provides evidence of self-similarity in the rifting process. PMID:24469260

Effects of medially wedged foot orthoses on knee and hip joint running mechanics in females with and without patellofemoral pain syndrome.

PubMed

Boldt, Andrew R; Willson, John D; Barrios, Joaquin A; Kernozek, Thomas W

2013-02-01

We examined the effects of medially wedged foot orthoses on knee and hip joint mechanics during running in females with and without patellofemoral pain syndrome (PFPS). We also tested if these effects depend on standing calcaneal eversion angle. Twenty female runners with and without PFPS participated. Knee and hip joint transverse and frontal plane peak angle, excursion, and peak internal knee and hip abduction moment were calculated while running with and without a 6° full-length medially wedged foot orthoses. Separate 3-factor mixed ANOVAs (group [PFPS, control] x condition [medial wedge, no medial wedge] x standing calcaneal angle [everted, neutral, inverted]) were used to test the effect of medially wedged orthoses on each dependent variable. Knee abduction moment increased 3% (P = .03) and hip adduction excursion decreased 0.6° (P < .01) using medially wedged foot orthoses. No significant group x condition or calcaneal angle x condition effects were observed. The addition of medially wedged foot orthoses to standardized running shoes had minimal effect on knee and hip joint mechanics during running thought to be associated with the etiology or exacerbation of PFPS symptoms. These effects did not appear to depend on injury status or standing calcaneal posture.

Contrasting catastrophic eruptions predicted by different intrusion and collapse scenarios.

PubMed

Rincón, M; Márquez, A; Herrera, R; Alonso-Torres, A; Granja-Bruña, J L; van Wyk de Vries, B

2018-04-18

Catastrophic volcanic eruptions triggered by landslide collapses can jet upwards or blast sideways. Magma intrusion is related to both landslide-triggered eruptive scenarios (lateral or vertical), but it is not clear how such different responses are produced, nor if any precursor can be used for forecasting them. We approach this problem with physical analogue modelling enhanced with X-ray Multiple Detector Computed Tomography scanning, used to track evolution of internal intrusion, and its related faulting and surface deformation. We find that intrusions produce three different volcano deformation patterns, one of them involving asymmetric intrusion and deformation, with the early development of a listric slump fault producing pronounced slippage of one sector. This previously undescribed early deep potential slip surface provides a unified explanation for the two different eruptive scenarios (lateral vs. vertical). Lateral blast only occurs in flank collapse when the intrusion has risen into the sliding block. Otherwise, vertical rather than lateral expansion of magma is promoted by summit dilatation and flank buttressing. The distinctive surface deformation evolution detected opens the possibility to forecast the possible eruptive scenarios: laterally directed blast should only be expected when surface deformation begins to develop oblique to the first major fault.

Hydrous melt-rock reaction in the shallow mantle wedge

NASA Astrophysics Data System (ADS)

Mitchell, A.; Grove, T. L.

2017-12-01

In subduction zone magmatism, hotter, deeper hydrous mantle melts rise and interact with the shallower, cooler depleted mantle in the uppermost part of the mantle wedge. Here, we experimentally investigate these hydrous reactions using three different ratios of a 1.6 GPa mantle melt and an overlying 1.2 GPa harzburgite from 1060 to 1260 °C. At low ratios of melt/mantle (20:80 and 5:95), the crystallizing assemblages are dunites, harzburgites, and lherzolites (as a function of temperature). When the ratio of deeper melt to overlying mantle is 70:30, the crystallizing assemblage is a wehrlite. This shows that wehrlites, which are observed in ophiolites and mantle xenoliths, can be formed by large amounts of deeper melt fluxing though the mantle wedge during ascent. In all cases, orthopyroxene dissolves in the melt, and olivine crystallizes along with pyroxenes and spinel. The amount of reaction between deeper melts and overlying mantle, simulated here by the three starting compositions, imposes a strong influence on final melt compositions, particularly in terms of depletion. At the lowest melt/mantle ratios, the resulting melt is an extremely depleted Al-poor, high-Si andesite. As the fraction of melt to mantle increases, final melts resemble primitive basaltic andesites found in arcs globally. Wall rock temperature is a key variable; over a span of <80 °C, reaction with deeper melt creates the entire range of mantle lithologies from a depleted dunite to a harzburgite to a refertilized lherzolite. Together, the experimental phase equilibria, melt compositions, and calculated reaction coefficients provide a framework for understanding how melt-wall rock reaction occurs in the natural system during melt ascent in the mantle wedge.

Emplacement of the early Miocene Pinto Peak intrusion, Southwest Utah, USA

NASA Astrophysics Data System (ADS)

Petronis, Michael S.; O'Driscoll, Brian

2013-12-01

In this contribution, we report rock magnetic, petrographic, and anisotropy of magnetic susceptibility (AMS) data from the Pinto Peak intrusion, all of which bear on volcanic construction. Rock magnetic data indicate that the dominant magnetic mineral phase is low-Ti titanomagnetite of multidomain grain size, the composition of which varies spatially across the intrusion. The intrusion is a porphyritic andesite dominated by Ca-rich plagioclase (>60%) as well as biotite, amphibole, olivine, and opaque minerals. Reflected light petrography reveals mostly euhedral-subhedral (titano)magnetite crystals that often form clustered glomerocrysts and stringers of equant crystals, without exhibiting a consistent mineral alignment fabric. Moderate-to-shallow plunging prolate magnetic susceptibility ellipsoids dominate the northern part of the intrusion while steeply dipping/plunging magnetic susceptibility ellipsoids are generally restricted to the southern part of the intrusion. The vent facies rocks yield moderate-to-steep oblate susceptibility ellipsoids. We interpret the flow pattern in the north to reflect subhorizontal flow of magma, filling a tabular sheet-like body associated with propagation of the intrusion to the north. We argue that the southern part of the intrusion represents the ascent site of the magma rising to shallow crustal levels along a steep feeder system. The oblate magnetic fabrics in the vent area plausibly represent flattening against the conduit walls as evidenced by a weak planar flow foliation observed in the vent conduit rocks. On reaching shallow crustal levels, the magma deformed and uplifted the roof rocks leading to gravitational instability. As the slide mass released from the roof, an explosive eruption ensued resulting in the emplacement of the Rocks of Paradise tuff and associated effusive lava flows. Following eruption, magma pressure decreased and the magma drained northward forming the northern intrusive phase.

Measurement of Rayleigh Wave Beams Using Angle Beam Wedge Transducers as the Transmitter and Receiver with Consideration of Beam Spreading

PubMed Central

Zhang, Shuzeng; Li, Xiongbing; Jeong, Hyunjo

2017-01-01

A theoretical model, along with experimental verification, is developed to describe the generation, propagation and reception of a Rayleigh wave using angle beam wedge transducers. The Rayleigh wave generation process using an angle beam wedge transducer is analyzed, and the actual Rayleigh wave sound source distributions are evaluated numerically. Based on the reciprocity theorem and considering the actual sound source, the Rayleigh wave beams are modeled using an area integral method. The leaky Rayleigh wave theory is introduced to investigate the reception of the Rayleigh wave using the angle beam wedge transducers, and the effects of the wave spreading in the wedge and transducer size are considered in the reception process. The effects of attenuations of the Rayleigh wave and leaky Rayleigh wave are discussed, and the received wave results with different sizes of receivers are compared. The experiments are conducted using two angle beam wedge transducers to measure the Rayleigh wave, and the measurement results are compared with the predictions using different theoretical models. It is shown that the proposed model which considers the wave spreading in both the sample and wedges can be used to interpret the measurements reasonably. PMID:28632183

Measurement of Rayleigh Wave Beams Using Angle Beam Wedge Transducers as the Transmitter and Receiver with Consideration of Beam Spreading.

PubMed

Zhang, Shuzeng; Li, Xiongbing; Jeong, Hyunjo

2017-06-20

A theoretical model, along with experimental verification, is developed to describe the generation, propagation and reception of a Rayleigh wave using angle beam wedge transducers. The Rayleigh wave generation process using an angle beam wedge transducer is analyzed, and the actual Rayleigh wave sound source distributions are evaluated numerically. Based on the reciprocity theorem and considering the actual sound source, the Rayleigh wave beams are modeled using an area integral method. The leaky Rayleigh wave theory is introduced to investigate the reception of the Rayleigh wave using the angle beam wedge transducers, and the effects of the wave spreading in the wedge and transducer size are considered in the reception process. The effects of attenuations of the Rayleigh wave and leaky Rayleigh wave are discussed, and the received wave results with different sizes of receivers are compared. The experiments are conducted using two angle beam wedge transducers to measure the Rayleigh wave, and the measurement results are compared with the predictions using different theoretical models. It is shown that the proposed model which considers the wave spreading in both the sample and wedges can be used to interpret the measurements reasonably.

Configuration and Generation of Substorm Current Wedge

NASA Astrophysics Data System (ADS)

Chu, Xiangning

The substorm current wedge (SCW), a core element of substorm dynamics coupling the magnetotail to the ionosphere, is crucial in understanding substorms. It has been suggested that the field-aligned currents (FACs) in the SCW are caused by either pressure gradients or flow vortices, or both. Our understanding of FAC generations is based predominately on numerical simulations, because it has not been possible to organize spacecraft observations in a coordinate system determined by the SCW. This dissertation develops an empirical inversion model of the current wedge and inverts midlatitude magnetometer data to obtain the parameters of the current wedge for three solar cycles. This database enables statistical data analysis of spacecraft plasma and magnetic field observations relative to the SCW coordinate. In chapter 2, a new midlatitude positive bay (MPB) index is developed and calculated for three solar cycles of data. The MPB index is processed to determine the substorm onset time, which is shown to correspond to the auroral breakup onset with at most 1-2 minutes difference. Substorm occurrence rate is found to depend on solar wind speed while substorm duration is rather constant, suggesting that substorm process has an intrinsic pattern independent of external driving. In chapter 3, an SCW inversion technique is developed to determine the strength and locations of the FACs in an SCW. The inversion parameters for FAC strength and location, and ring current strength are validated by comparison with other measurements. In chapter 4, the connection between earthward flows and auroral poleward expansion is examined using improved mapping, obtained from a newly-developed dynamic magnetospheric model by superimposing a standard magnetospheric field model with substorm current wedge obtained from the inversion technique. It is shown that the ionospheric projection of flows observed at a fixed point in the equatorial plane map to the bright aurora as it expands poleward

Salt

USGS Publications Warehouse

Franson, J.C.; Friend, M.

1999-01-01

Animals become victims of salt poisoning or toxicosis when toxic levels of sodium and chloride accumulate in the blood after they ingest large amounts of salt or, in some species, are deprived of water. For birds, salt sources may include saline water and road salt.Normally, the salt glands of birds (Fig. 47.1) excrete sodium and chloride to maintain the proper physiologic chemical balance. However, when there has been insufficient time for acclimation of the salt gland to the saline environment, or when salt gland function is compromised by exposure to certain pesticides or oil, the electrolyte balance of the blood may be upset by the excess sodium and chloride, resulting in toxicosis. Salt accumulation on the outside of the body, or salt encrustation, is a greater problem for waterbirds that use very saline waters than is salt toxicosis. Salt encrustation can lead to exertion, acute muscle degeneration, and eventual drowning during the struggle to escape entrapment.

Modal Composition and Age of Intrusions in North-Central and Northeast Nevada

USGS Publications Warehouse

du Bray, Edward A.; Crafford, A. Elizabeth Jones

2007-01-01

Introduction Data presented in this report characterize igneous intrusions of north-central and northeast Nevada and were compiled as part of the Metallogeny of the Great Basin project conducted by the U.S. Geological Survey (USGS) between 2001 and 2007. The compilation pertains to the area bounded by lats 38.5 and 42 N., long 118.5 W., and the Nevada-Utah border (fig. 1). The area contains numerous large plutons and smaller stocks but also contains equally numerous smaller, shallowly emplaced intrusions, including dikes, sills, and endogenous dome complexes. Igneous intrusions (hereafter, intrusions) of multiple ages are major constituents of the geologic framework of north-central and northeast Nevada (Stewart and Carlson, 1978). Mesozoic and Cenozoic intrusions are particularly numerous and considered to be related to subduction along the west edge of the North American plate during this time. Henry and Ressel (2000) and Ressel and others (2000) have highlighted the association between magmatism and ore deposits along the Carlin trend. Similarly, Theodore (2000) has demonstrated the association between intrusions and ore deposits in the Battle Mountain area. Decades of geologic investigations in north-central and northeast Nevada (hereafter, the study area) demonstrate that most hydrothermal ore deposits are spatially, and probably temporally and genetically, associated with intrusions. Because of these associations, studies of many individual intrusions have been conducted, including those by a large number of Master's and Doctoral thesis students (particularly University of Nevada at Reno students and associated faculty), economic geologists working on behalf of exploration and mining companies, and USGS earth scientists. Although the volume of study area intrusions is large and many are associated with ore deposits, no synthesis of available data that characterize these rocks has been assembled. Compilations that have been produced for intrusions in Nevada

The role of heterogeneous fluid pressures in the shape of critical-taper submarine wedges, with application to Barbados

NASA Astrophysics Data System (ADS)

Yeh, En-Chao; Suppe, John

2014-05-01

Some classic accretionary wedges such as Nankai trough and Barbados are mechanically heterogeneous based on their spatial variation in taper, showing inward decrease in surface slope α without covariation in detachment dip β. Possible sources of regional heterogeniety include variation in fluid pressure, density, cohesion and fault strength, which can be constrained by the seismic or borehole observable parameter, fluid-retention depth Z_FRD, below which compaction is strongly diminished. In particular the Hubbert-Rubey fluid-pressure weakening can be addressed as (1-lambda)~0.6Z_FRD/Z. We recast the heterogeneous critical-taper wedge theory of Dahlen (1990) in terms of the observable Z_FRD/H, where H is the detachment depth, which allows for real world applications. For example, seismic velocity and borehole data from the Barbados shows that the fluid-retention depth Z_FRD is approximately constant and Z_FRD/H decreases inward. This leads to a factor of four inward decreases in wedge strength, dominated by fluid pressure, with only a second-order role for density and cohesion. An inward decrease in wedge strength should by itself produce an increase in taper, therefore the observed decreasing taper must be dominated by decreasing fault strength mu_b* from 0.03 to 0.01. Static fluid-pressures along the detachment in equilibrium with the overlying wedge predict the observed wedge geometry well, given a constant intrinsic friction coefficient mu_b=0.15.

Efficient cooling of rocky planets by intrusive magmatism

NASA Astrophysics Data System (ADS)

Lourenço, Diogo L.; Rozel, Antoine B.; Gerya, Taras; Tackley, Paul J.

2018-05-01

The Earth is in a plate tectonics regime with high surface heat flow concentrated at constructive plate boundaries. Other terrestrial bodies that lack plate tectonics are thought to lose their internal heat by conduction through their lids and volcanism: hotter planets (Io and Venus) show widespread volcanism whereas colder ones (modern Mars and Mercury) are less volcanically active. However, studies of terrestrial magmatic processes show that less than 20% of melt volcanically erupts, with most melt intruding into the crust. Signatures of large magmatic intrusions are also found on other planets. Yet, the influence of intrusive magmatism on planetary cooling remains unclear. Here we use numerical magmatic-thermo-mechanical models to simulate global mantle convection in a planetary interior. In our simulations, warm intrusive magmatism acts to thin the lithosphere, leading to sustained recycling of overlying crustal material and cooling of the mantle. In contrast, volcanic eruptions lead to a thick lithosphere that insulates the upper mantle and prevents efficient cooling. We find that heat loss due to intrusive magmatism can be particularly efficient compared to volcanic eruptions if the partitioning of heat-producing radioactive elements into the melt phase is weak. We conclude that the mode of magmatism experienced by rocky bodies determines the thermal and compositional evolution of their interior.

Magmatism significantly alters the thermal structure of the wedge

NASA Astrophysics Data System (ADS)

Rees Jones, D. W.; Katz, R. F.; Rudge, J. F.; Tian, M.

2016-12-01

The temperature structure of the mantle wedge is typically modelled as a balance between thermal diffusion and advection by the solid mantle [e.g., 1]. The thermal state of the wedge promotes melting and melt transport in the natural system, but the thermal consequences of these processes have been neglected from previous models. We show that advective transport of sensible and latent heat by liquid magma can locally alter the temperature structure from canonical models by up to 200K. Liquids are liberated from the subducting slab by de-volatilization reactions. They trigger melting and become silicic en route to the surface, where they cause arc volcanism. These liquids transport heat advectively, and consume or supply latent heat as they melt or freeze. To analyse these effects, we parameterise melting in the presence of volatile species. We combine this with a one-dimensional "melting-column model," previously used to understand mid-ocean ridge volcanism. Our calculations highlight the thermal and chemical response to melt transport across the mantle wedge. Finally, we solve two-dimensional geodynamic models with a prescribed slab flux [2]. These models allow us to identify the most thermally significant fluxes of melt in the system. Perturbations of 200K are found at the base of the overriding lithosphere. This thermal signature of melt migration should be considered when interpreting heat flow, petrologic and seismic data [e.g., 3]. Such a thermal perturbation is likely to affect the chemistry of arc volcanoes, the solid mantle flow and, perhaps, the location of the volcanos themselves [4]. [1] van Keken, P. E., Currie, C., King, S. D., Behn, M. D., Cagnioncle, A., He, J., et al. (2008). A community benchmark for subduction zone modeling. PEPI, doi:10.1016/j.pepi.2008.04.015 [2] Wilson, C. R., Spiegelman, M., van Keken, P. E., & Hacker, B. R. (2014). Fluid flow in subduction zones: The role of solid rheology and compaction pressure. EPSL, doi:10.1016/j

Sulfide intrusion in the tropical seagrasses Thalassia testudinum and Syringodium filiforme

NASA Astrophysics Data System (ADS)

Holmer, Marianne; Pedersen, Ole; Krause-Jensen, Dorte; Olesen, Birgit; Hedegård Petersen, Malene; Schopmeyer, Stephanie; Koch, Marguerite; Lomstein, Bente Aa.; Jensen, Henning S.

2009-11-01

Sulfur and oxygen dynamics in the seagrasses Thalassia testudinum and Syringodium filiforme and their sediments were studied in the US Virgin Islands (USVI) in order to explore sulfide intrusion into tropical seagrasses. Four study sites were selected based on the iron concentration in sediments and on proximity to anthropogenic nutrient sources. Meadow characteristics (shoot density, above- and below-ground biomass, nutrient content) were sampled along with sediment biogeochemistry. Sulfide intrusion was high in T. testudinum, as up to 96% of total sulfur in the plant was derived from sediment-derived sulfides. The sulfide intrusion was negatively correlated to the turnover of sulfides in the sediments regulated by both plant parameters and sediment sulfur pools. Sediment iron content played an indirect role by affecting sulfide turnover rates. Leaf production was negatively correlated with sulfide intrusion suggesting that active growth reduced sulfide intrusion. Sulfide intrusion was lower in S. filiforme (up to 44%) compared to T. testudinum consistent with a higher internal nighttime oxygen concentrations found for S. filiforme. When S. filiforme can take advantage of its ability to maintain high internal oxygen concentrations, as was the case on the USVI, it could increase its success in colonizing unvegetated disturbed sediments with potentially high sulfide concentrations.

Psychological Intrusion – An Overlooked Aspect of Dental Fear

PubMed Central

Chapman, Helen R.; Kirby-Turner, Nick

2018-01-01

Dental fear/anxiety is a widely recognised problem affecting a large proportion of the population. It can result in avoidance and/or difficulty accepting dental care. We believe that psychological intrusion may play a role in the aetiology and maintenance of dental fear for at least some individuals. In this narrative review we will take a developmental perspective in order to understand its impact across the lifespan. We will consider the nature of ‘self,’ parenting styles, the details of intrusive parenting or parental psychological control, and briefly touch upon child temperament and parental anxiety. Finally, we draw together the supporting (largely unrecognised) evidence available in the dental literature. We illustrate the paper with clinical examples and discuss possibly effective ways of addressing the problem. We conclude that psychological intrusion appears to play an important role in dental fear, for at least some individuals, and we call for detailed research into the extent and exact nature of the problem. A simple means of identifying individuals who are vulnerable to psychological intrusion would be useful for dentists. PMID:29719519

Iron clad wetlands: Soil iron-sulfur buffering determines coastal wetland response to salt water incursion

NASA Astrophysics Data System (ADS)

Schoepfer, Valerie A.; Bernhardt, Emily S.; Burgin, Amy J.

2014-12-01

Coastal freshwater wetland chemistry is rapidly changing due to increased frequency of salt water incursion, a consequence of global change. Seasonal salt water incursion introduces sulfate, which microbially reduces to sulfide. Sulfide binds with reduced iron, producing iron sulfide (FeS), recognizable in wetland soils by its characteristic black color. The objective of this study is to document iron and sulfate reduction rates, as well as product formation (acid volatile sulfide (AVS) and chromium reducible sulfide (CRS)) in a coastal freshwater wetland undergoing seasonal salt water incursion. Understanding iron and sulfur cycling, as well as their reduction products, allows us to calculate the degree of sulfidization (DOS), from which we can estimate how long soil iron will buffer against chemical effects of sea level rise. We show that soil chloride, a direct indicator of the degree of incursion, best predicted iron and sulfate reduction rates. Correlations between soil chloride and iron or sulfur reduction rates were strongest in the surface layer (0-3 cm), indicative of surface water incursion, rather than groundwater intrusion at our site. The interaction between soil moisture and extractable chloride was significantly related to increased AVS, whereas increased soil chloride was a stronger predictor of CRS. The current DOS in this coastal plains wetland is very low, resulting from high soil iron content and relatively small degree of salt water incursion. However, with time and continuous salt water exposure, iron will bind with incoming sulfur, creating FeS complexes, and DOS will increase.

Evidence for Patchy Sediment Underthrusting and a Strong, Drained Outer Accretionary Wedge in Central Cascadia: Implications for Dynamic Slip Conditions

NASA Astrophysics Data System (ADS)

Tobin, H. J.; Webb, S. I.

2017-12-01

The central Cascadia subduction zone forearc in the region offshore Washington, where a hot, young incoming plate is covered by a 2-3 km thick sedimentary sequence, features a wide, very narrowly-tapered outer accretionary wedge composed of landward vergent thrust sheets. Longstanding questions for this region include the position and host-rock environment of the plate boundary décollement fault, the thickness of sedimentary strata underthrust beneath the wedge with the downgoing plate, and the effective stress or pore fluid pressure condition in the wedge and along its base. We have analyzed nine multichannel seismic lines of the 2012 COAST multi-channel seismic reflection survey using both time- and depth- migrated seismic sections for structural interpretation. Results show that there is evidence for two parallel décollement levels, with up to 200 - 500 meters thickness of a mostly-underthrust sequence in places, but which is absent entirely in others. This patchy distribution is mapped and related to features of the overlying wedge structure. We also analyzed the seismic interval velocity distribution produced during pre-stack depth migration imaging, and used it to compute estimated porosity, pore fluid pressure, and effective stress via empirical physical properties transforms. We find that the wedge shows evidence for at most only modest, localized excess pore pressure, and instead most of the wedge appears to be at near-hydrostatic, drained condition. Modest overpressure ratios of up to only 0.15 are detected, localized in the footwalls of thrust splays. We find no evidence for overpressure zones in the underthrust sequence below the upper décollement, in contrast to findings from several other wedges worldwide. Taken together, the accretionary wedge structure and apparent low pore pressure condition here is consistent with a mechanically strong wedge overlying a base that is very weak, at least transiently. By analogy with recent work from Sumatra

SU-E-T-362: Enhanced Dynamic Wedge Output Factors for Varian 2300CD and the Case for a Reference Database

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

Njeh, C

2015-06-15

Purpose: Dose inhomogeneity in treatment planning can be compensated using physical wedges. Enhanced dynamic wedges (EDW) were introduced by Varian to overcome some of the short comings of physical wedges. The objectives of this study were to measure EDW output factors for 6 MV and 20 MV photon energies for a Varian 2300CD. Secondly to review the literature in terms of published enhanced dynamic wedge output factors (EDWOF) for different Varian models and thereby adding credence to the case of the validity of reference databases. Methods: The enhanced dynamic wedge output factors were measured for the Varian 2300CD for bothmore » 6 MV and 20 MV photon energies. Twelve papers with published EDWOF for different Varian Linac models were found in the literature. Results: The EDWOF for 6 MV varied from 0.980 for a 5×5 cm 10 degree wedge to 0.424 for 20×20 cm 60 degree wedge. Similarly for 20 MV, the EDWOF varied from 0.986 for 5×5 cm 10 degree wedge to 0.529 for 20×20 cm 60 degree wedge. EDWOF are highly dependent on field size. Comparing our results with the published mean, we found an excellent agreement for 6 MV EDWOF with the percentage differences ranging from 0.01% to 0.57% with a mean of 0.03%. The coefficient of variation of published EDWOF ranged from 0.17% to 0.85% and 0.1% to 0.9% for the for 6 MV and 18MV photon energies respectively. This paper provides the first published EDWOF for 20 MV photon energy. In addition, we have provided the first compendium of EDWOFs for different Varian linac models. Conclusion: The consistency of EDWOF across models and institution provide further support that, a standard data set of basic photon and electron dosimetry could be established, as a guide for future commissioning, beam modeling and quality assurance purposes.« less

Inducing and modulating intrusive emotional memories: a review of the trauma film paradigm.

PubMed

Holmes, Emily A; Bourne, Corin

2008-03-01

Highly affect-laden memory intrusions are a feature of several psychological disorders with intrusive images of trauma especially associated with post-traumatic stress disorder (PTSD). The trauma film paradigm provides a prospective experimental tool for investigating analogue peri-traumatic cognitive mechanisms underlying intrusion development. We review several historical papers and some more recent key studies that have used the trauma film paradigm. A heuristic diagram is presented, designed to simplify predictions about analogue peri-traumatic processing and intrusion development, which can also be related to the processing elements of recent cognitive models of PTSD. Results show intrusions can be induced in the laboratory and their frequency amplified/attenuated in line with predictions. Successful manipulations include competing task type (visuospatial vs. verbal) and use of a cognitive coping strategy. Studies show that spontaneous peri-traumatic dissociation also affects intrusion frequency although attempts to manipulate dissociation have failed. It is hoped that further use of this paradigm may lead to prophylactic training for at risk groups and an improved understanding of intrusions across psychopathologies.

Deep intrusions, lateral magma transport and related uplift at ocean island volcanoes

NASA Astrophysics Data System (ADS)

Klügel, Andreas; Longpré, Marc-Antoine; García-Cañada, Laura; Stix, John

2015-12-01

Oceanic intraplate volcanoes grow by accumulation of erupted material as well as by coeval or discrete magmatic intrusions. Dykes and other intrusive bodies within volcanic edifices are comparatively well studied, but intrusive processes deep beneath the volcanoes remain elusive. Although there is geological evidence for deep magmatic intrusions contributing to volcano growth through uplift, this has rarely been demonstrated by real-time monitoring. Here we use geophysical and petrological data from El Hierro, Canary Islands, to show that intrusions from the mantle and subhorizontal transport of magma within the oceanic crust result in rapid endogenous island growth. Seismicity and ground deformation associated with a submarine eruption in 2011-2012 reveal deep subhorizontal intrusive sheets (sills), which have caused island-scale uplift of tens of centimetres. The pre-eruptive intrusions migrated 15-20 km laterally within the lower oceanic crust, opening pathways that were subsequently used by the erupted magmas to ascend from the mantle to the surface. During six post-eruptive episodes between 2012 and 2014, further sill intrusions into the lower crust and upper mantle have caused magma to migrate up to 20 km laterally, resulting in magma accumulation exceeding that of the pre-eruptive phase. A comparison of geobarometric data for the 2011-2012 El Hierro eruption with data for other Atlantic intraplate volcanoes shows similar bimodal pressure distributions, suggesting that eruptive phases are commonly accompanied by deep intrusions of sills and lateral magma transport. These processes add significant material to the oceanic crust, cause uplift, and are thus fundamentally important for the growth and evolution of volcanic islands. We suggest that the development of such a magma accumulation zone in the lower oceanic crust begins early during volcano evolution, and is a consequence of increasing size and complexity of the mantle reservoir system, and potentially

Appliance of Independent Component Analysis to System Intrusion Analysis

NASA Astrophysics Data System (ADS)

Ishii, Yoshikazu; Takagi, Tarou; Nakai, Kouji

In order to analyze the output of the intrusion detection system and the firewall, we evaluated the applicability of ICA(independent component analysis). We developed a simulator for evaluation of intrusion analysis method. The simulator consists of the network model of an information system, the service model and the vulnerability model of each server, and the action model performed on client and intruder. We applied the ICA for analyzing the audit trail of simulated information system. We report the evaluation result of the ICA on intrusion analysis. In the simulated case, ICA separated two attacks correctly, and related an attack and the abnormalities of the normal application produced under the influence of the attach.

State of the Practice of Intrusion Detection Technologies

DTIC Science & Technology

2000-01-01

security incident response teams ) - the role of IDS in threat management, such as defining alarm severity, monitoring, alerting, and policy-based...attacks in an effort to sneak under the radar of security specialists and intrusion detection software, a U.S. Navy network security team said today...to get the smoking gun," said Stephen Northcutt, head of the Shadow intrusion detection team at the Naval Surface Warfare Center. "To know what’s

Replacing intrusive thoughts: investigating thought control in relation to OCD symptoms.

PubMed

Ólafsson, Ragnar P; Snorrason, Ívar; Bjarnason, Reynar K; Emmelkamp, Paul M G; Ólason, Daníel Þ; Kristjánsson, Árni

2014-12-01

Control of obsessive thoughts in Obsessive Compulsive Disorder (OCD) involves both avoidance and removal of undesirable intrusive thoughts. Thought suppression tasks tap both of these processes but experimental results have been inconsistent. Experimental tasks allowing more focused study of the processes involved in controlling intrusive thoughts may be needed. In two experiments, control over neutral, standardized intrusive and personal intrusive thoughts was investigated as participants attempted to replace them with neutral thoughts. Non-selected university students (Experiment 1: N = 61) and university students scoring high and low on self-report measure of OC symptoms (Experiment 2: N = 40) performed a computerized thought replacement task. In experiment 1 replacing personal intrusive thoughts took longer than replacing neutral thoughts. Self-reports showed that intrusive thoughts were rated more difficult to replace and were associated with greater thought reoccurrence during replacement, larger emotional reaction and more discomfort. These results were largely replicated in experiment 2. Furthermore, the high OC symptom group experienced greater overall difficulty controlling thoughts on the replacement task, experienced more reoccurrences of personal intrusive thoughts, larger emotional reactions and discomfort associated with them, and felt a greater urge to remove them. All participants were non-clinical university students, and older adults with OCD should be tested. The findings are in line with cognitive behavioural theories of OCD. They support the usefulness of thought replacement as a research paradigm to study thought control in OCD and possibly other psychological conditions characterized by repetitive thoughts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Stratospheric Intrusion-Influenced Ozone Air Quality Exceedences Investigated in MERRA-2

NASA Technical Reports Server (NTRS)

Knowland, K. Emma; Ott, Lesley; Duncan, Bryan; Wargan, Krzysztof

2017-01-01

Ozone near the surface is harmful to human health and is a result of the photochemical reaction with both man-made and natural precursor pollutant sources. Therefore, in order to reduce near surface ozone concentrations, communities must reduce anthropogenic pollution sources. However, the injection of stratospheric ozone into the troposphere, known as a stratospheric intrusion, can also lead to concentrations of ground-level ozone exceeding air quality standards. Stratospheric intrusions are dynamical atmospheric features, however, these intrusions have been misrepresented in models and reanalyses until recently, as the features of a stratospheric intrusion are best identified in horizontal resolutions of approximately 50 km or smaller. NASA's Modern-Era Retrospective Analysis for Research and Applications Version-2 (MERRA-2) reanalysis is a publicly-available high-resolution dataset (50 km) with assimilated ozone that characterizes stratospheric ozone on the same spatiotemporal resolution as the meteorology. We show that stratospheric intrusions that impact surface air quality are well represented in the MERRA-2 reanalysis. This is demonstrated through a case study analysis of stratospheric intrusion events which were identified by the United States Environmental Protection Agency (EPA) to impact surface ozone air quality in spring 2012 in Colorado. The stratospheric intrusions are identified in MERRA-2 by the folding of the dynamical tropopause under the jet stream and subsequent isentropic descent of dry, O3-rich stratospheric air towards the surface where ozone air quality exceedences were observed. The MERRA-2 reanalysis can support air quality agencies for more rapid identification of the impact of stratospheric air on ground-level ozone.

Time, space, and composition relations among northern Nevada intrusive rocks and their metallogenic implications

USGS Publications Warehouse

duBray, E.A.

2007-01-01

Importantly, modal composition, age, and geochemical characteristics of intrusions associated with large mineral deposits along the trends, are indistinguishable from non-mineralized intrusions in northern Nevada and thus do not identify intrusions associated with significant deposits. Moreover, intrusion age and composition show little correlation with mineral-deposit type, abundance, and size. Given the lack of diagnostic characteristics for intrusions associated with deposits, it is uncertain whether age, modal composition, and geochemical data can identify intrusions associated with mineral deposits. These findings suggest that associations between northern Nevada intrusions and mineral deposits reflect superimposition of many geologic factors, none of which was solely responsible for mineral-deposit formation. These factors might include intrusion size, efficiency of fluid and metal extraction from magma, prevailing redox and sulfidation conditions, or derivation of metals and ligands from host rocks and groundwater. The abundance and diversity of mineral deposits in northern Nevada may partly reflect geochemical inheritance, for example, along the mineral trends rather than the influence of petrologically unique magma or associated fluids.

Magnetic fabric constraints of the emplacement of igneous intrusions

NASA Astrophysics Data System (ADS)

Maes, Stephanie M.

Fabric analysis is critical to evaluating the history, kinematics, and dynamics of geological deformation. This is particularly true of igneous intrusions, where the development of fabric is used to constrain magmatic flow and emplacement mechanisms. Fabric analysis was applied to three mafic intrusions, with different tectonic and petrogenetic histories, to study emplacement and magma flow: the Insizwa sill (Mesozoic Karoo Large Igneous Province, South Africa), Sonju Lake intrusion (Proterozoic Midcontinent Rift, Minnesota, USA), and Palisades sill (Mesozoic rift basin, New Jersey, USA). Multiple fabric analysis techniques were used to define the fabric in each intrusive body. Using digital image analysis techniques on multiple thin sections, the three-dimensional shape-preferred orientation (SPO) of populations of mineral phases were calculated. Low-field anisotropy of magnetic susceptibility (AMS) measurements were used as a proxy for the mineral fabric of the ferromagnetic phases (e.g., magnetite). In addition, a new technique---high-field AMS---was used to isolate the paramagnetic component of the fabric (e.g., silicate fabric). Each fabric analysis technique was then compared to observable field fabrics as a framework for interpretation. In the Insizwa sill, magnetic properties were used to corroborate vertical petrologic zonation and distinguish sub-units within lithologically defined units. Abrupt variation in magnetic properties provides evidence supporting the formation of the Insizwa sill by separate magma intrusions. Low-field AMS fabrics in the Sonju Lake intrusion exhibit consistent SW-plunging lineations and SW-dipping foliations. These fabric orientations provide evidence that the cumulate layers in the intrusion were deposited in a dynamic environment, and indicate magma flowed from southwest to northeast, parallel to the pre-existing rift structures. In the Palisades sill, the magnetite SPO and low-field AMS lineation have developed orthogonal to

Conjunctive Management of Multi-Aquifer System for Saltwater Intrusion Mitigation

NASA Astrophysics Data System (ADS)

Tsai, F. T. C.; Pham, H. V.

2015-12-01

Due to excessive groundwater withdrawals, many water wells in Baton Rouge, Louisiana experience undesirable chloride concentration because of saltwater intrusion. The study goal is to develop a conjunctive management framework that takes advantage of the Baton Rouge multi-aquifer system to mitigate saltwater intrusion. The conjunctive management framework utilizes several hydraulic control techniques to mitigate saltwater encroachment. These hydraulic control approaches include pumping well relocation, freshwater injection, saltwater scavenging, and their combinations. Specific objectives of the study are: (1) constructing scientific geologic architectures of the "800-foot" sand, the "1,000-foot" sand, the "1,200-foot" sand, the "1,500-foot" sand, the "1,700-foot" sand, and the "2,000-foot" sand, (2) developing scientific saltwater intrusion models for these sands. (3) using connector wells to draw native groundwater from one sand and inject to another sand to create hydraulic barriers to halt saltwater intrusion, (4) using scavenger wells or well couples to impede saltwater intrusion progress and reduce chloride concentration in pumping wells, and (5) reducing cones of depression by relocating and dispersing pumping wells to different sands. The study utilizes optimization techniques and newest LSU high performance computing (HPC) facilities to derive solutions. The conjunctive management framework serves as a scientific tool to assist policy makers to solve the urgent saltwater encroachment issue in the Baton Rouge area. The research results will help water companies as well as industries in East Baton Rouge Parish and neighboring parishes by reducing their saltwater intrusion threats, which in turn would sustain Capital Area economic development.

Role of ground ice dynamics and ecological feedbacks in recent ice wedge degradation and stabilization

USGS Publications Warehouse

Mark Torre Jorgenson,; Mikhail Kanevskiy,; Yuri Shur,; Natalia Moskalenko,; Dana Brown,; Wickland, Kimberly P.; Striegl, Robert G.; Koch, Joshua C.

2015-01-01

Ground ice is abundant in the upper permafrost throughout the Arctic and fundamentally affects terrain responses to climate warming. Ice wedges, which form near the surface and are the dominant type of massive ice in the Arctic, are particularly vulnerable to warming. Yet processes controlling ice wedge degradation and stabilization are poorly understood. Here we quantified ice wedge volume and degradation rates, compared ground ice characteristics and thermal regimes across a sequence of five degradation and stabilization stages and evaluated biophysical feedbacks controlling permafrost stability near Prudhoe Bay, Alaska. Mean ice wedge volume in the top 3 m of permafrost was 21%. Imagery from 1949 to 2012 showed thermokarst extent (area of water-filled troughs) was relatively small from 1949 (0.9%) to 1988 (1.5%), abruptly increased by 2004 (6.3%) and increased slightly by 2012 (7.5%). Mean annual surface temperatures varied by 4.9°C among degradation and stabilization stages and by 9.9°C from polygon center to deep lake bottom. Mean thicknesses of the active layer, ice-poor transient layer, ice-rich intermediate layer, thermokarst cave ice, and wedge ice varied substantially among stages. In early stages, thaw settlement caused water to impound in thermokarst troughs, creating positive feedbacks that increased net radiation, soil heat flux, and soil temperatures. Plant growth and organic matter accumulation in the degraded troughs provided negative feedbacks that allowed ground ice to aggrade and heave the surface, thus reducing surface water depth and soil temperatures in later stages. The ground ice dynamics and ecological feedbacks greatly complicate efforts to assess permafrost responses to climate change.

Role of ground ice dynamics and ecological feedbacks in recent ice wedge degradation and stabilization

NASA Astrophysics Data System (ADS)

Jorgenson, M. T.; Kanevskiy, M.; Shur, Y.; Moskalenko, N.; Brown, D. R. N.; Wickland, K.; Striegl, R.; Koch, J.

2015-11-01

Ground ice is abundant in the upper permafrost throughout the Arctic and fundamentally affects terrain responses to climate warming. Ice wedges, which form near the surface and are the dominant type of massive ice in the Arctic, are particularly vulnerable to warming. Yet processes controlling ice wedge degradation and stabilization are poorly understood. Here we quantified ice wedge volume and degradation rates, compared ground ice characteristics and thermal regimes across a sequence of five degradation and stabilization stages and evaluated biophysical feedbacks controlling permafrost stability near Prudhoe Bay, Alaska. Mean ice wedge volume in the top 3 m of permafrost was 21%. Imagery from 1949 to 2012 showed thermokarst extent (area of water-filled troughs) was relatively small from 1949 (0.9%) to 1988 (1.5%), abruptly increased by 2004 (6.3%) and increased slightly by 2012 (7.5%). Mean annual surface temperatures varied by 4.9°C among degradation and stabilization stages and by 9.9°C from polygon center to deep lake bottom. Mean thicknesses of the active layer, ice-poor transient layer, ice-rich intermediate layer, thermokarst cave ice, and wedge ice varied substantially among stages. In early stages, thaw settlement caused water to impound in thermokarst troughs, creating positive feedbacks that increased net radiation, soil heat flux, and soil temperatures. Plant growth and organic matter accumulation in the degraded troughs provided negative feedbacks that allowed ground ice to aggrade and heave the surface, thus reducing surface water depth and soil temperatures in later stages. The ground ice dynamics and ecological feedbacks greatly complicate efforts to assess permafrost responses to climate change.

Neoproterozoic sand wedges: crack formation in frozen soils under diurnal forcing during a snowball Earth

NASA Astrophysics Data System (ADS)

Maloof, Adam C.; Kellogg, James B.; Anders, Alison M.

2002-11-01

Thermal contraction cracking of permafrost produced sand-wedge polygons at sea level on the paleo-equator during late Neoproterozoic glacial episodes. These sand wedges have been used as evidence for high (≥54°) paleo-obliquity of the Earth's ecliptic, because cracks that form wedges are hypothesized to require deep seasonal cooling so the depth of the stressed layer in the ground reaches ≥1 m, similar to the measured depths of cracks that form wedges. To test the counter hypothesis that equatorial cracks opened under a climate characterized by a strong diurnal cycle and low mean annual temperature (snowball Earth conditions), we examine crack formation in frozen ground subject to periodic temperature variations. We derive analytical expressions relating the Newtonian viscosity to the potential crack depth, concluding that cracks will form only in frozen soils with viscosities greater than ˜10 14 Pa s. We also show numerical calculations of crack growth in frozen soils with stress- and temperature-dependent rheologies and find that fractures may propagate to depths 3-25 times the depth of the thermally stressed layer in equatorial permafrost during a snowball Earth because the mean annual temperature is low enough to keep the ground cold and brittle to relatively great depths.

Accretion in the wake of terrane collision: The Neogene accretionary wedge off Kenai Peninsula, Alaska

USGS Publications Warehouse

Fruehn, J.; von Huene, Roland E.; Fisher, M.A.

1999-01-01

Subduction accretion and repeated terrane collision shaped the Alaskan convergent margin. The Yakutat Terrane is currently colliding with the continental margin below the central Gulf of Alaska. During the Neogene the terrane's western part was subducted after which a sediment wedge accreted along the northeast Aleutian Trench. This wedge incorporates sediment eroded from the continental margin and marine sediments carried into the subduction zone on the Pacific plate. Prestack depth migration was performed on six seismic reflection lines to resolve the structure within this accretionary wedge and its backstop. The lateral extent of the structures is constrained by high-resolution swath bathymetry and seismic lines collected along strike. Accretionary structure consists of variably sized thrust slices that were deformed against a backstop during frontal accretion and underplating. Toward the northeast the lower slope steepens, the wedge narrows, and the accreted volume decreases notwith-standing a doubling of sediments thickness in the trench. In the northeasternmost transect, near the area where the terrane's trailing edge subducts, no frontal accretion is observed and the slope is eroded. The structures imaged along the seismic lines discussed here most likely result from progressive evolution from erosion to accretion, as the trailing edge of the Yakutat Terrane is subducting.

3D seismic investigation of the structural and stratigraphic characteristics of the Pagasa Wedge, Southwest Palawan Basin, Philippines, and their tectonic implications

NASA Astrophysics Data System (ADS)

Ilao, Kimberly A.; Morley, Christopher K.; Aurelio, Mario A.

2018-04-01

The Pagasa Wedge is a poorly imaged deepwater orogenic wedge that has been variously interpreted as representing an accretionary prism, a former accretionary prism modified by thrusting onto a thinned continental margin, and a gravity-driven fold-thrust belt. This study, using 2D and 3D seismic data, together with well information indicates that at least the external part of the wedge is dominantly composed of mass transport complexes, capped by syn-kinematic sediments that have thrusts and normal faults superimposed upon them. Drilling shows that despite stratigraphic repetition of Eocene Middle Miocene units, there is stratigraphic omission of Oligocene and Early Miocene units. This absence suggests that mass transport processes have introduced the Eocene section into the wedge rather than tectonic thrusting. The accretionary prism stage (Oligocene) of the Central Palawan Ophiolite history appears to be marked by predominantly north-vergent deformation. The Deep Regional Unconformity (∼17 Ma) likely indicates the approximate time when obduction ceased in Palawan. The Pagasa Wedge is a late-stage product of the convergence history that was active in its final phase sometime above the top of the Nido Limestone (∼16 Ma) and the base of the Tabon Limestone in the Aboabo-A1X well (∼9 Ma). The top of the wedge is traditionally associated with the Middle Miocene Unconformity (MMU), However the presence of multiple unconformities, diachronous formation tops, local tectonic unconformities and regional diachronous events (e.g. migrating forebulges) all suggest simply giving a single age (or assigning a single unconformity, such as the MMU as defining the top of the Pagasa Wedge is inappropriate. The overall NE-SW trend of the wedge, and the dominant NW transport of structures within the wedge diverge from the more northerly transport direction determined from outcrops in Palawan, and also from the Nido Limestone in the SW part of the Pagasa Wedge. Possibly this NW

Influence of Age, Thought Content, and Anxiety on Suppression of Intrusive Thoughts

PubMed Central

Beadel, Jessica R.; Green, Jennifer S.; Hosseinbor, Shahrzad; Teachman, Bethany A.

2013-01-01

Understanding differences in responses following attempts to suppress versus simply monitor intrusive thoughts is important given the established relationship between intrusive thinking and numerous forms of psychopathology. Moreover, these differences may vary as a function of age. Because of the links between aging and both enhancement in emotion regulation skills and decline in inhibition skills, older and younger adults were expected to differ in their responses (e.g., experience of negative affect and thought recurrence) to attempts at suppressing intrusive thoughts. This study examined whether efforts to suppress thought content that varied in valence and age-relevance differentially affected older (N = 40, aged 66–92) and younger (N = 42, aged 16–25) adults’ ability to inhibit intrusive thought recurrence and their resulting negative affect. Interestingly, older adults experienced less recurrence for most thoughts than younger adults. Also, for several dependent variables (negative affect and perceived difficulty suppressing intrusive thoughts), older adults showed less decline in their magnitude of response across thinking periods (i.e., from suppression to monitoring) than did younger adults. These age effects were not generally moderated by level of trait anxiety, though higher anxiety did predict intrusive thought responding in expected directions, such as greater negative affect. These findings point to independent influences of age and anxiety, and suggest a complex mix of risk and protective factors for older adults’ responses to intrusive thoughts. PMID:23395408

Petrogenesis of the Ni-Cu-PGE sulfide-bearing Tamarack Intrusive Complex, Midcontinent Rift System, Minnesota

NASA Astrophysics Data System (ADS)

Taranovic, Valentina; Ripley, Edward M.; Li, Chusi; Rossell, Dean

2015-01-01

The Tamarack Intrusive Complex (TIC, 1105.6 ± 1.2 Ma) in NE Minnesota, was emplaced during the early stages of the development of the Midcontinent Rift System (MRS, "Early Stage": 1110-1106 Ma). Country rocks of the TIC are those of the Paleoproterozoic Thomson Formation, part of the Animikie Group including sulfide-bearing metasedimentary black shale. The magmatic system is composed of at least two principal mafic-ultramafic intrusive sequences: the sulfide-barren Bowl Intrusion in the south and the "dike" area intrusions in the north which host Ni-Cu-Platinum Group Elements (PGE) mineralization with up to 2.33% Ni, 1.24% Cu, 0.34 g/t Pt, 0.23 g/t Pd and 0.18 g/t Au. Two distinct intrusive units in the "dike" area are the CGO (coarse-grained olivine-bearing) Intrusion, a sub-vertical dike-like body, and the overlying sub-horizontal FGO (fine-grained olivine-bearing) Intrusion. Both intrusions comprise peridotite, feldspathic peridotite, feldspathic pyroxenite, melatroctolite and melagabbro. Massive sulfides are volumetrically minor and mainly occur as lenses emplaced into the country rocks associated with both intrusions. Semi-massive (net-textured) sulfides are distributed at the core of the CGO Intrusion, surrounded by a halo of the disseminated sulfides. Disseminated sulfides also occur in lenses along the base of the FGO Intrusion. Olivine compositions in the CGO Intrusion are between Fo89 and Fo82 and in the FGO Intrusion from Fo84 to Fo82. TIC intrusions have more primitive olivine compositions than that of olivine in the sheet-like intrusions in the Duluth Complex (below Fo70), as well as olivine from the smaller, conduit-related, Eagle and East Eagle Intrusions in Northern Michigan (Fo86 to Fo75). The FeO/MgO ratios of the CGO and FGO Intrusion parental magmas, inferred from olivine compositions, are similar to those of picritic basalts erupted during the early stages of the MRS formation. Trace element ratios differ slightly from other intrusions in the

Using the salt tectonics as a proxy to reveal post-rift active crustal tectonics: The example of the Eastern Sardinian margin

NASA Astrophysics Data System (ADS)

Lymer, Gaël; Vendeville, Bruno; Gaullier, Virginie; Chanier, Frank; Gaillard, Morgane

2017-04-01

The Western Tyrrhenian Basin, Mediterranean Sea, is a fascinating basin in terms of interactions between crustal tectonics, salt tectonics and sedimentation. The METYSS (Messinian Event in the Tyrrhenian from Seismic Study) project is based on 2100 km of HR seismic data acquired in 2009 and 2011 along the Eastern Sardinian margin. The main aim is to study the Messinian Salinity Crisis (MSC) in the Western Tyrrhenian Basin, but we also investigate the thinning processes of the continental crust and the timing of crustal vertical motions across this complex domain. Our first results allowed us to map the MSC seismic markers and to better constrain the timing of the rifting, which ended before the MSC across the upper and middle parts of the margin. We also evidenced that crustal activity persisted long after the end of rifting. This has been particularly observed on the upper margin, where several normal faults and a surprising compressional structure were recently active. In this study we investigate the middle margin, the Cornaglia Terrace, where the Mobile Unit (MU, mobile Messinian salt) accumulated during the MSC and acts as a décollement. Our goal is to ascertain whether or not crustal tectonics existed after the pre-MSC rift. This is a challenge where the MU is thick, because potential basement deformations could be first accommodated by the MU and therefore would not find any expression in the supra-salt layers (Upper Unit, UU and Plio-Quaternary, PQ). However our investigations clearly reveal interactions between crustal and salt tectonics along the margin. We thus evidence gravity gliding of the salt and its brittle sedimentary cover along basement slopes generated by the post-MSC tilting of some basement blocks bounded by crustal normal faults, formerly due to the rifting. Another intriguing structure also got our interest. It corresponds to a wedge-shaped of MU located in a narrow N-S half graben bounded to the west by a major, east-verging, crustal

Effects of Sleep after Experimental Trauma on Intrusive Emotional Memories

PubMed Central

Kleim, Birgit; Wysokowsky, Julia; Schmid, Nuria; Seifritz, Erich; Rasch, Björn

2016-01-01

Study Objectives: To investigate sleep's effect in the immediate aftermath of experiencing an analog trauma in the laboratory on reducing intrusive emotional memory formation. Methods: Sixty-five healthy women were exposed to an experimental laboratory trauma. They viewed a neutral and a trauma film in the laboratory and were randomly allocated to either a group that slept following film viewing or a group that remained awake. Sleep was recorded with electroencephalogram in a subgroup of participants in the sleep group. All participants recorded intrusive memories in the week following the film. Results: The sleep group experienced fewer and less distressing intrusive trauma memories compared to the wake group. These effects were particularly evident toward the end of the week. Duration spent in stage N2 as opposed to light N1 sleep, a higher number of fast parietal sleep spindles and a lower rapid eye movement sleep density predicted intrusion frequency. Conclusions: Our results have clinical implications and set the ground for early-intervention sleep studies following trauma and prevention of chronic posttrauma disorders. Citation: Kleim B, Wysokowsky J, Schmid N, Seifritz E, Rasch B. Effects of sleep after experimental trauma on intrusive emotional memories. SLEEP 2016;39(12):2125–2132. PMID:27748249

Evolution and timing of salt diapirism in the Iranian sector of the Persian Gulf

NASA Astrophysics Data System (ADS)

Perotti, Cesare; Chiariotti, Luca; Bresciani, Ilenia; Cattaneo, Luciano; Toscani, Giovanni

2016-06-01

The Iranian sector of the Persian Gulf is affected by more than 30 large diapiric structures triggered by the mobilization of the Infracambrian Hormuz Complex, an evaporite-rich unit that overlies Precambrian basement at the base of the sedimentary succession. Nineteen non-piercing diapirs, without any appreciable salt intrusion into the upper succession, were studied in detail and retro-deformed by the decompaction and unfolding of 13 seismic horizons that were identified by the interpretation of a dense grid of 2D seismic lines and calibrated by well data. Salt uplift had begun by the Early Palaeozoic and persists to the present day, with major pulses of intensity during the Middle Triassic, Cenomanian, Late Oligocene, and post-Middle Miocene. The structural reconstructions and the analysis of the progressive deformation of the study diapirs do not show any link between diapiric uplift and local tectonic structures, and no clear correlation with the regional geodynamic events acting at the boundary of the Arabian plate. On the contrary, the salt uplift seems strongly influenced by the differential rate of sedimentation that affected the whole study basin (more than 40,000 km2), with a coefficient of correlation between the salt uplift rate and the differential rate of sedimentation (expressed by the standard deviation of the sedimentation rate calculated over the entire basin) of 0.95. This downbuilding mechanism of diapiric growth is apparently induced by differential sedimentation over long distances (several tens of kilometers), showing that the flow of salt affected the whole basin and not just the areas around the single diapiric structures.

Final OSWER Vapor Intrusion Guidance

EPA Science Inventory

EPA is preparing to finalize its guidance on assessing and addressing vapor intrusion, which is defined as migration of volatile constituents from contaminated media in the subsurface (soil or groundwater) into the indoor environment. In November 2002, EPA issued draft guidance o...

Implementing and testing a fiber-optic polarization-based intrusion detection system

NASA Astrophysics Data System (ADS)

Hajj, Rasha El; MacDonald, Gregory; Verma, Pramode; Huck, Robert

2015-09-01

We describe a layer-1-based intrusion detection system for fiber-optic-based networks. Layer-1-based intrusion detection represents a significant elevation in security as it prohibits an adversary from obtaining information in the first place (no cryptanalysis is possible). We describe the experimental setup of the intrusion detection system, which is based on monitoring the behavior of certain attributes of light both in unperturbed and perturbed optical fiber links. The system was tested with optical fiber links of various lengths and types, under different environmental conditions, and under changes in fiber geometry similar to what is experienced during tapping activity. Comparison of the results for perturbed and unperturbed links has shown that the state of polarization is more sensitive to intrusion activity than the degree of polarization or power of the received light. The testing was conducted in a simulated telecommunication network environment that included both underground and aerial links. The links were monitored for intrusion activity. Attempts to tap the link were easily detected with no apparent degradation in the visual quality of the real-time surveillance video.

[Radiocarbon dating of pollen and spores in wedge ice from Iamal and Kolyma].

PubMed

Vasil'chuk, A K

2004-01-01

Radiocarbon dating of pollen concentrate from late Pleistocene syngenetic wedge ice was carried out using acceleration mass spectrometry (AMS) in Seyakha and Bizon sections. Comparison of the obtained dating with palynological analysis and AMS radiocarbon dating previously obtained for other organic fractions of the same samples allowed us to evaluate accuracy of dating of different fractions. Quantitative tests for data evaluation were considered in terms of possible autochthonous or allochthonous accumulation of the material on the basis of pre-Pleistocene pollen content in these samples. Paleoecological information content of pollen spectra from late Pleistocene syngenetic wedge ice was evaluated.

RANS Analyses of Turbofan Nozzles with Internal Wedge Deflectors for Noise Reduction

NASA Technical Reports Server (NTRS)

DeBonis, James R.

2009-01-01

Computational fluid dynamics (CFD) was used to evaluate the flow field and thrust performance of a promising concept for reducing the noise at take-off of dual-stream turbofan nozzles. The concept, offset stream technology, reduces the jet noise observed on the ground by diverting (offsetting) a portion of the fan flow below the core flow, thickening and lengthening this layer between the high-velocity core flow and the ground observers. In this study a wedge placed in the internal fan stream is used as the diverter. Wind, a Reynolds averaged Navier-Stokes (RANS) code, was used to analyze the flow field of the exhaust plume and to calculate nozzle performance. Results showed that the wedge diverts all of the fan flow to the lower side of the nozzle, and the turbulent kinetic energy on the observer side of the nozzle is reduced. This reduction in turbulent kinetic energy should correspond to a reduction in noise. However, because all of the fan flow is diverted, the upper portion of the core flow is exposed to the freestream, and the turbulent kinetic energy on the upper side of the nozzle is increased, creating an unintended noise source. The blockage due to the wedge reduces the fan mass flow proportional to its blockage, and the overall thrust is consequently reduced. The CFD predictions are in very good agreement with experimental flow field data, demonstrating that RANS CFD can accurately predict the velocity and turbulent kinetic energy fields. While this initial design of a large scale wedge nozzle did not meet noise reduction or thrust goals, this study identified areas for improvement and demonstrated that RANS CFD can be used to improve the concept.

Deciphering assumptions about stepped wedge designs: the case of Ebola vaccine research.

PubMed

Doussau, Adélaïde; Grady, Christine

2016-12-01

Ethical concerns about randomising persons to a no-treatment arm in the context of Ebola epidemic led to consideration of alternative designs. The stepped wedge (SW) design, in which participants or clusters are randomised to receive an intervention at different time points, gained popularity. Common arguments in favour of using this design are (1) when an intervention is likely to do more good than harm, (2) all participants should receive the experimental intervention at some time point during the study and (3) the design might be preferable for practical reasons. We examine these assumptions when considering Ebola vaccine research. First, based on the claim that a stepped wedge design is indicated when it is likely that the intervention will do more good than harm, we reviewed published and ongoing SW trials to explore previous use of this design to test experimental drugs or vaccines, and found that SW design has never been used for trials of experimental drugs or vaccines. Given that Ebola vaccines were all experimental with no prior efficacy data, the use of a stepped wedge design would have been unprecedented. Second, we show that it is rarely true that all participants receive the intervention in SW studies, but rather, depending on certain design features, all clusters receive the intervention. Third, we explore whether the SW design is appealing for feasibility reasons and point out that there is significant complexity. In the setting of the Ebola epidemic, spatiotemporal variation may have posed problematic challenges to a stepped wedge design for vaccine research. Finally, we propose a set of points to consider for scientific reviewers and ethics committees regarding proposals for SW designs. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Maxillary molar intrusion with micro-implant anchorage (MIA).

PubMed

Park, Hyo-Sang; Jang, Bong-Kyu; Kyung, Hee-Moon

2005-11-01

Intrusion of the maxillary molars is difficult to accomplish using traditional methods of anchorage. To describe methods of maxillary molar intrusion with the aid of micro-implants. Micro-implants provide stable intra-oral anchorage and enable the maxillary molars to be intruded without the usual side effects. Three adult patients are presented showing how micro-implants can be used to intrude the maxillary molars. In the first patient micro-implants were placed in the alveolar process between the second premolar and first molar, in the second patient micro-implants were placed in the palatal alveolar process between the first and second molars, and in the third patient a micro-implant was placed in the palate paramedially. A transpalatal bar was used to prevent bucco- or linguoversion of the molars during intrusion. The maxillary molars can be intruded with intra-oral anchorage derived from microscrew implants.

Design of an Evolutionary Approach for Intrusion Detection

PubMed Central

2013-01-01

A novel evolutionary approach is proposed for effective intrusion detection based on benchmark datasets. The proposed approach can generate a pool of noninferior individual solutions and ensemble solutions thereof. The generated ensembles can be used to detect the intrusions accurately. For intrusion detection problem, the proposed approach could consider conflicting objectives simultaneously like detection rate of each attack class, error rate, accuracy, diversity, and so forth. The proposed approach can generate a pool of noninferior solutions and ensembles thereof having optimized trade-offs values of multiple conflicting objectives. In this paper, a three-phase, approach is proposed to generate solutions to a simple chromosome design in the first phase. In the first phase, a Pareto front of noninferior individual solutions is approximated. In the second phase of the proposed approach, the entire solution set is further refined to determine effective ensemble solutions considering solution interaction. In this phase, another improved Pareto front of ensemble solutions over that of individual solutions is approximated. The ensemble solutions in improved Pareto front reported improved detection results based on benchmark datasets for intrusion detection. In the third phase, a combination method like majority voting method is used to fuse the predictions of individual solutions for determining prediction of ensemble solution. Benchmark datasets, namely, KDD cup 1999 and ISCX 2012 dataset, are used to demonstrate and validate the performance of the proposed approach for intrusion detection. The proposed approach can discover individual solutions and ensemble solutions thereof with a good support and a detection rate from benchmark datasets (in comparison with well-known ensemble methods like bagging and boosting). In addition, the proposed approach is a generalized classification approach that is applicable to the problem of any field having multiple conflicting

The Effects of a Heel Wedge on Hip, Pelvis and Trunk Biomechanics During Squatting in Resistance Trained Individuals.

PubMed

Charlton, Jesse M; Hammond, Connor A; Cochrane, Christopher K; Hatfield, Gillian L; Hunt, Michael A

2017-06-01

Barbell back squats are a popular exercise for developing lower extremity strength and power. However, this exercise has potential injury risks, particularly to the lumbar spine, pelvis, and hip joint. Previous literature suggests heel wedges as a means of favorably adjusting trunk and pelvis kinematics with the intention of reducing such injury risks. Yet no direct biomechanical research exists to support these recommendations. Therefore, the purpose of this study was to examine the effects of heel wedges compared with barefoot on minimally loaded barbell back squats. Fourteen trained male participants performed a barbell back squat in bare feet or with their feet raised bilaterally with a 2.5-cm wooden block while 3-dimensional kinematics, kinetics, and electromyograms were collected. The heel wedge condition elicited significantly less forward trunk flexion angles at peak knee flexion, and peak external hip joint moments (p ≤ 0.05) compared with barefoot conditions. However, no significant differences were observed between conditions for trunk and pelvis angle differences at peak knee flexion (p > 0.05). Lastly, no peak or root mean square differences in muscle activity were elicited between conditions (p > 0.05). Our results lend support for the suggestions provided in literature aimed at using heel wedges as a means of reducing excessive forward trunk flexion. However, the maintenance of a neutral spine, another important safety factor, is not affected by the use of heel wedges. Therefore, heel wedges may be a viable modification for reduction of excessive forward trunk flexion but not for reduction in relative trunk-pelvis flexion during barbell back squats.

The Cimmerian accretionary wedge of Anarak, Central Iran

NASA Astrophysics Data System (ADS)

Zanchi, Andrea; Malaspina, Nadia; Zanchetta, Stefano; Berra, Fabrizio; Benciolini, Luca; Bergomi, Maria; Cavallo, Alessandro; Javadi, Hamid Reza; Kouhpeyma, Meyssam

2015-04-01

The occurrence in Iran of several ophiolite belts dating between Late Palaeozoic to Triassic poses several questions on the possible existence of various sutures marking the closure of the Palaeotethys ocean between Eurasia and this Gondwana-derived microplate. In this scenario, the Anarak region in Central Iran still represents a conundrum. Contrasting geochronological, paleontological, paleomagnetic data and reported field evidence suggest different origins for the Anarak Metamorphic Complex (AMC). The AMC is either interpreted, as: (1) relict of an accretionary wedge developed at the Eurasia margin during the Palaeotethys subduction as part of the Cimmerian suture zone of NE Iran, displaced to Central Iran by a large counter-clockwise rotation of the central Iranian blocks; (2) autochthonous unit forming a secondary branch of the main suture zone. Our structural, petrographic and geochemical data indicate that the AMC consists of several metamorphic units also including dismembered "ophiolites" which display different tectono-metamorphic evolutions. Three main ductile deformational events can be distinguished in the AMC. The Morghab and Chah Gorbeh complexes preserve a different M1 metamorphism, characterized by blueschist relics in the S1 foliation of the former unit, and greenschist assemblages in the latter. They share a subsequent similar D2 deformational and M2 metamorphic history, showing a prograde metamorphism with syn- to post-deformation growth of blueschist facies mineral assemblages on pre-existing greenschist facies associations. High pressure, low temperature (HP/LT) metamorphism responsible for the growth of sodic amphibole has been recognized also within marble lenses at the contact between the Chah Gorbeh Complex and serpentinites. Evidence of HP/LT metamorphism also occurs in glaucophane-bearing meta-pillow lavas and serpentinites, which contain antigorite and form most of the "ophiolites" within the AMC. Structural relationships show that the

Brownian diffusion and thermophoresis mechanisms in Casson fluid over a moving wedge

NASA Astrophysics Data System (ADS)

Ullah, Imran; Shafie, Sharidan; Khan, Ilyas; Hsiao, Kai Long

2018-06-01

The effect of Brownian diffusion and thermophoresis on electrically conducting mixed convection flow of Casson fluid induced by moving wedge is investigated in this paper. It is assumed that the wedge is saturated in a porous medium and experiences the thermal radiation and chemical reaction effects. The transformed nonlinear governing equations are solved numerically by Keller box scheme. Findings reveal that increase in Casson and magnetic parameters reduced the boundary layer thickness. The effect of Brownian motion and thermophoresis parameters are more pronounced on temperature profile as compared to nanoparticles concentration. The presence of thermal radiation assisted the heat transfer rate significantly. The influence of magnetic parameter is observed less significant on temperature and nanoparticles concentration.

Pre-stressor cognitive control is related to intrusive cognition of a stressful film.

PubMed

Wessel, Ineke; Overwijk, Sippie; Verwoerd, Johan; de Vrieze, Nienke

2008-04-01

It has been suggested that relatively weak cognitive control existing prior to a stressful event may be associated with intrusive memories of that stressor afterwards. We explored this in two analog studies employing unselected participants who saw an emotional film fragment and completed behavioral (i.e., color-naming interference [CNI]) and self-report indices of intrusions. Prior to film presentation, several cognitive control tests were administered. Study 1 showed that better updating/monitoring was linked to less CNI from negative film-related words. However, better updating/monitoring was associated with more diary reports of intrusive memories. Study 2 showed that a better resistance to pro-active interference (PI) predicted less self-reported film-related intrusive cognition after 24h. However, after this delay, both self-reported intrusions and CNI were not related to updating/monitoring. Taken together, the results suggest that a specific pre-existing cognitive control function (i.e., resistance to PI) may be involved in the regulation of post-stressor intrusive memory phenomena.

Layered intrusion formation by top down thermal migration zone refining (Invited)

NASA Astrophysics Data System (ADS)

Lundstrom, C.

2009-12-01

The formation of layered mafic intrusions by crystallization from cooling magmas represents the textbook example of igneous differentiation, often attributed to fractional crystallization through gravitational settling. Yet in detail, such interpretations have significant problems such that it remains unclear how these important features form. Put in the Earth perspective that no km scale blob of >50% melt has ever been imaged geophysically and that geochronological studies repeatedly indicate age inconsistencies with “big tank” magma chambers, it may be questioned if km scale magma chambers have ever existed. I will present the case for forming layered intrusions by a top down process whereby arriving basaltic magma reaches a permeability barrier, begins to underplate and forms the intrusion incrementally by sill injection with the body growing downward at ~1 mm/yr rate or less. A temperature gradient zone occurs in the overlying previously emplaced sills, leading to chemical components migrating by diffusion. As long as the rate of diffusion can keep up with rate of sill addition, the body will differentiate along a path similar to a liquid line of descent. In this talk, I will integrate data from 3 areas: 1) laboratory experiments examining the behavior of partially molten silicates in a temperature gradient (thermal migration); 2) numerical modeling of the moving temperature gradient zone process using IRIDIUM (Boudreau, 2003); 3) measurements of Fe isotope ratios and geochronology from the Sonju Lake Intrusion in the Duluth Complex. This model provides the ability to form km scale intrusions by a seismically invisible means, can explain million year offsets in chronology, and has implications for reef development and PGE concentration. Most importantly, this model of top down layered intrusion formation, following a similar recent proposal for granitoid formation (Lundstrom, 2009), represents a testable hypothesis: because temperature gradient driven

Flow rate limitation in open wedge channel under microgravity

NASA Astrophysics Data System (ADS)

Wei, YueXing; Chen, XiaoQian; Huang, YiYong

2013-08-01

A study of flow rate limitation in an open wedge channel is reported in this paper. Under microgravity condition, the flow is controlled by the convection and the viscosity in the channel as well as the curvature of the liquid free surface. A maximum flow rate is achieved when the curvature cannot balance the pressure difference leading to a collapse of the free surface. A 1-dimensional theoretical model is used to predict the critical flow rate and calculate the shape of the free surface. Computational Fluid Dynamics tool is also used to simulate the phenomenon. Results show that the 1-dimensional model overestimates the critical flow rate because extra pressure loss is not included in the governing equation. Good agreement is found in 3-dimensional simulation results. Parametric study with different wedge angles and channel lengths show that the critical flow rate increases with increasing the cross section area; and decreases with increasing the channel length. The work in this paper can help understand the surface collapsing without gravity and for the design in propellant management devices in satellite tanks.

In-situ trainable intrusion detection system