WorldWideScience

Sample records for buildup

  1. Mars base buildup scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Blacic, J.D.

    1985-01-01

    Two surface base build-up scenarios are presented in order to help visualize the mission and to serve as a basis for trade studies. In the first scenario, direct manned landings on the Martian surface occur early in the missions and scientific investigation is the main driver and rationale. In the second scenario, early development of an infrastructure to exploite the volatile resources of the Martian moons for economic purposes is emphasized. Scientific exploration of the surface is delayed at first, but once begun develops rapidly aided by the presence of a permanently manned orbital station.

  2. From detached to attached buildup complexes

    DEFF Research Database (Denmark)

    Rafaelsen, B.; Elvebakk, G.; Andreassen, K.

    2008-01-01

    warm- and cool-water carbonate buildups from the Finnmark Platform is controlled by faults and the sea floor morphology at the time of their growth. A fluctuating sea level affected the growth of the carbonate buildups, but they also influenced their own environment by forming lagoons, atoll...

  3. Momentum management strategy during Space Station buildup

    Science.gov (United States)

    Bishop, Lynda; Malchow, Harvey; Hattis, Philip

    1988-01-01

    The use of momentum storage devices to control effectors for Space Station attitude control throughout the buildup sequence is discussed. Particular attention is given to the problem of providing satisfactory management of momentum storage effectors throughout buildup while experiencing variable torque loading. Continuous and discrete control strategies are compared and the effects of alternative control moment gyro strategies on peak momentum storage requirements and on commanded maneuver characteristics are described.

  4. Understanding nutrient build-up on urban road surfaces.

    Science.gov (United States)

    Miguntanna, Nandika Prasadani; Goonetilleke, Ashantha; Egodowatta, Prasanna; Kokot, Serge

    2010-01-01

    This article discusses the outcomes of a research project on nutrients build-up on urban road surfaces. Nutrient build-up was investigated on road sites belonging to residential, industrial and commercial land use. Collected build-up samples were separated into five particle size ranges and were tested for total nitrogen (TN), total phosphorus (TP) and sub species of nutrients, namely, NO2-, NO3-, TKN and PO4(3-). Multivariate analytical techniques were used to analyse the data and to develop detailed understanding on buildup. Data analysis revealed that the solids loads on urban road surfaces are highly influenced by factors such as land use, antecedent dry period and traffic volume. However, the nutrient build-up process was found to be independent of the type of land use. It was solely dependent on the particle size of solids build-up. Most of the nutrients were associated with the particle size range build-up. It is also important to consider the difference in the composition of nitrogen and phosphorus build-up in the context of designing effective stormwater quality mitigation strategies.

  5. Metal transfer and build-up in friction and cutting

    CERN Document Server

    Kuznetsov, V D

    1956-01-01

    Metal Transfer and Build-up in Friction and Cutting aims to systematize our knowledge of the metal build-up, to describe some of the investigations past and present carried out in SFTI (Tomsk), and to make an effort to explain a number of the phenomena in cutting, scratching, and sliding from the point of view of metal transfer theory. The book opens with a chapter on the temperature of the rubbing interface of two solids. This temperature is needed in order to elucidate the nature of the formation of a build-up in scratching, cutting, and sliding. Separate chapters follow on the seizure phen

  6. Prediction of sulphide build-up in filled sewer pipes.

    Science.gov (United States)

    Alani, Amir M; Faramarzi, Asaad; Mahmoodian, Mojtaba; Tee, Kong Fah

    2014-08-01

    Millions of dollars are being spent worldwide on the repair and maintenance of sewer networks and wastewater treatment plants. The production and emission of hydrogen sulphide has been identified as a major cause of corrosion and odour problems in sewer networks. Accurate prediction of sulphide build-up in a sewer system helps engineers and asset managers to appropriately formulate strategies for optimal sewer management and reliability analysis. This paper presents a novel methodology to model and predict the sulphide build-up for steady state condition in filled sewer pipes. The proposed model is developed using a novel data-driven technique called evolutionary polynomial regression (EPR) and it involves the most effective parameters in the sulphide build-up problem. EPR is a hybrid technique, combining genetic algorithm and least square. It is shown that the proposed model can provide a better prediction for the sulphide build-up as compared with conventional models.

  7. An alternating renewal process describes the buildup of perceptual segregation.

    Science.gov (United States)

    Steele, Sara A; Tranchina, Daniel; Rinzel, John

    2014-01-01

    For some ambiguous scenes perceptual conflict arises between integration and segregation. Initially, all stimulus features seem integrated. Then abruptly, perhaps after a few seconds, a segregated percept emerges. For example, segregation of acoustic features into streams may require several seconds. In behavioral experiments, when a subject's reports of stream segregation are averaged over repeated trials, one obtains a buildup function, a smooth time course for segregation probability. The buildup function has been said to reflect an underlying mechanism of evidence accumulation or adaptation. During long duration stimuli perception may alternate between integration and segregation. We present a statistical model based on an alternating renewal process (ARP) that generates buildup functions without an accumulative process. In our model, perception alternates during a trial between different groupings, as in perceptual bistability, with random and independent dominance durations sampled from different percept-specific probability distributions. Using this theory, we describe the short-term dynamics of buildup observed on short trials in terms of the long-term statistics of percept durations for the two alternating perceptual organizations. Our statistical-dynamics model describes well the buildup functions and alternations in simulations of pseudo-mechanistic neuronal network models with percept-selective populations competing through mutual inhibition. Even though the competition model can show history dependence through slow adaptation, our statistical switching model, that neglects history, predicts well the buildup function. We propose that accumulation is not a necessary feature to produce buildup. Generally, if alternations between two states exhibit independent durations with stationary statistics then the associated buildup function can be described by the statistical dynamics of an ARP.

  8. Carbonate Buildups in the Pernambuco Basin, NE Brazil

    Directory of Open Access Journals (Sweden)

    BRUNO V. BUARQUE

    Full Text Available ABSTRACT The Pernambuco Basin represents one of the most prominent regions for deep water oil and gas exploration off the Brazilian coast. This study aims to identify and describe the occurrence of carbonate buildups in the offshore regions of the basin. The study was based on an analysis of a set of 143 2D time-migrated seismic sections that cover the offshore region of the Pernambuco Basin. An interpretation of the seismic dataset was used to define the main seismic sequences related to the main regional pulses of deposition and to identify three main groups of carbonate buildups: 1 shelf margin reefs, 2 patch reefs, and 3 isolated carbonate buildups. The carbonate buildups formed in two main intervals during post-rift sequences of the Santonian-Maastrichtian and Paleocene-Middle Miocene, which extend the known periods of carbonate deposit formation in the basin. The formation of carbonate buildups was controlled by the tectonic evolution of the Pernambuco Plateau, which created a series of paleotopographic highs that enabled the establishment of oceanographically and climatically favorable conditions for carbonate formation and deposition. These findings are important for understanding the evolution of the basin and for future evaluations of its petroleum potential.

  9. Ceramic backup ring prevents undesirable weld-metal buildup

    Science.gov (United States)

    Leonard, G. E.

    1971-01-01

    Removable ceramic backup material butted against weld zone back prevents weld metal buildup at that site. Method is successful with manual tungsten-inert gas /TIG/ welding of 316 corrosion resistant steel /CRES/ pieces with 0.76 cm throat diameter and 1.57 cm pipe internal diameter.

  10. Branched Polymer Models and the Mechanism of Multilayer Film Buildup

    Science.gov (United States)

    Waduge, Pradeep; Khadka, Dhan; Haynie, Donald

    2012-02-01

    The ``in and out diffusion'' hypothesis does not provide a sufficient explanation of the exponential buildup displayed by some polyelectrolyte multilayer film systems. Here, we report initial tests of an alternative view, on which the completion of each adsorption cycle results in an increase in the number of polymer binding sites on the film surface. Polycationic dendrimeric peptides, which can potentially bind several oppositely-charged peptides each, have been designed, synthesized and utilized in comparative film buildup experiments. Material deposited, internal film structure and film surface morphology have been studied by ultraviolet spectroscopy (UVS), circular dichroism spectroscopy (CD), quartz crystal microbalance (QCM) and atomic force microscopy (AFM). Polycations tended to contribute more to film buildup than did polyanions on quartz but not on gold. Increasing the number of branches in the dendrimeric peptides from 4 to 8 reproducibly resulted in an increase in the film growth rate on quartz but not on gold. Peptide backbones tended to adopt a β-strand conformation on incorporation into a film. Thicker films had a greater surface roughness than thin films. The data are consistent with film buildup models in which the average number of polymer binding sites will increase with each successive adsorption cycle in the range where exponential growth is displayed.

  11. Damage buildup and edge dislocation mobility in equiatomic multicomponent alloys

    Energy Technology Data Exchange (ETDEWEB)

    Granberg, F., E-mail: fredric.granberg@helsinki.fi [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Djurabekova, F. [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Helsinki Institute of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Levo, E.; Nordlund, K. [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland)

    2017-02-15

    Highlights: • We studied the damage buildup in equiatomic multicomponent alloys by MD simulations. • Edge dislocation mobility was lower in the studied alloys compared to elemental Ni. • Damage buildup in alloys saturated at lower levels than in elemental Ni. • Initial damage buildup is faster in alloys compared to elemental Ni. - Abstract: A new class of single phase metal alloys of equal atomic concentrations has shown very promising mechanical properties and good corrosion resistance. Moreover, a significant reduction in damage accumulation during prolonged irradiation has also been observed in these equiatomic multicomponent alloys. A comparison of elemental Ni with the two component NiFe- and the three component NiCoCr-alloy showed a substantial reduction in damage in both alloys, and an even larger difference was seen if only larger clusters were considered. One of the factors limiting the damage build-up in the alloys compared to the elemental material was seen to be dislocation mobility (Granberg et al., 2016). In this Article, we focus on a more thorough investigation of the mobility of edge dislocations in different cases of the Ni-, NiFe- and NiCoCr-samples. We find that even though the saturated amount of defects in the alloys is lower than in elemental Ni, the defect buildup in the early stages is faster in the alloys. We also find that the dislocation mobility in NiFe is lower than in Ni, at low stresses, and that the onset stress in NiFe is higher than in Ni. The same phenomenon was seen in comparison between NiFe and NiCoCr, since the three component alloy had lower dislocation mobility and higher onset stress. The dislocation velocity in elemental Ni plateaued out just under the forbidden velocity, whereas the alloys showed a more complex behaviour.

  12. Review of GEM Radiation Belt Dropout and Buildup Challenges

    Science.gov (United States)

    Tu, Weichao; Li, Wen; Morley, Steve; Albert, Jay

    2017-04-01

    In Summer 2015 the US NSF GEM (Geospace Environment Modeling) focus group named "Quantitative Assessment of Radiation Belt Modeling" started the "RB dropout" and "RB buildup" challenges, focused on quantitative modeling of the radiation belt buildups and dropouts. This is a community effort which includes selecting challenge events, gathering model inputs that are required to model the radiation belt dynamics during these events (e.g., various magnetospheric waves, plasmapause and density models, electron phase space density data), simulating the challenge events using different types of radiation belt models, and validating the model results by comparison to in situ observations of radiation belt electrons (from Van Allen Probes, THEMIS, GOES, LANL/GEO, etc). The goal is to quantitatively assess the relative importance of various acceleration, transport, and loss processes in the observed radiation belt dropouts and buildups. Since 2015, the community has selected four "challenge" events under four different categories: "storm-time enhancements", "non-storm enhancements", "storm-time dropouts", and "non-storm dropouts". Model inputs and data for each selected event have been coordinated and shared within the community to establish a common basis for simulations and testing. Modelers within and outside US with different types of radiation belt models (diffusion-type, diffusion-convection-type, test particle codes, etc.) have participated in our challenge and shared their simulation results and comparison with spacecraft measurements. Significant progress has been made in quantitative modeling of the radiation belt buildups and dropouts as well as accessing the modeling with new measures of model performance. In this presentation, I will review the activities from our "RB dropout" and "RB buildup" challenges and the progresses achieved in understanding radiation belt physics and improving model validation and verification.

  13. Build-up algorithm for atomic correspondence between chemical structures.

    Science.gov (United States)

    Kawabata, Takeshi

    2011-08-22

    Determining a one-to-one atom correspondence between two chemical compounds is important to measure molecular similarities and to find compounds with similar biological activities. This calculation can be formalized as the maximum common substructure (MCS) problem, which is well-studied and has been shown to be NP-complete. Although many rigorous and heuristic algorithms have been developed, none of these algorithms is sufficiently fast and accurate. We developed a new program, called "kcombu" using a build-up algorithm, which is a type of the greedy heuristic algorithms. The program can search connected and disconnected MCSs as well as topologically constrained disconnected MCS (TD-MCS), which is introduced in this study. To evaluate the performance of our program, we prepared two correct standards: the exact correspondences generated by the maximum clique algorithms and the 3D correspondences obtained from superimposed 3D structure of the molecules in a complex 3D structure with the same protein. For the five sets of molecules taken from the protein structure database, the agreement value between the build-up and the exact correspondences for the connected MCS is sufficiently high, but the computation time of the build-up algorithm is much smaller than that of the exact algorithm. The comparison between the build-up and the 3D correspondences shows that the TD-MCS has the best agreement value among the other types of MCS. Additionally, we observed a strong correlation between the molecular similarity and the agreement with the correct and 3D correspondences; more similar molecule pairs are more correctly matched. Molecular pairs with more than 40% Tanimoto similarities can be correctly matched for more than half of the atoms with the 3D correspondences.

  14. Dust build-up on surfaces in the indoor environment

    Science.gov (United States)

    Kildesø, Jan; Vallarino, Jose; Spengler, John D.; Brightman, Howard S.; Schneider, Thomas

    The concentration and the composition of dust in the indoor environment has been associated with reported symptoms of the sick building syndrome. Levels of airborne concentrations of dust particles are well known. However, the relation to dust on surfaces for office environments are not well described. In this study, 662 measurements were performed of surface dust concentrations on hard surfaces in 19 buildings within Harvard University based on a sticking gelatine foil method. The measure is the dust covered area of the surface as a percentage. In three offices, the build-up of dust on surfaces was measured for a period of five days. Close to these surfaces the airborne PM 2.5 and PM 10 particle mass concentrations were measured simultanously. A significant correlation between the dust build-up and the difference between the PM 10 and the PM 2.5 was established. The particle size distribution was measured by means of an Aerodynamic Particle Sizer. The mean dust build-up normalized with the measured PM 10 was approximately four times higher than the equivalent calculated by a deposition model. This may in part be due to the effect of preferred orientation when particles settle to a surface. Different data for dust on surfaces and airborne particles in offices were compared. The levels of airborne particles in offices in Europe seem to be higher than the levels in the US.

  15. Middle Cambrian siliceous sponge-calcimicrobe buildups (Daegi Formation, Korea): Metazoan buildup constituents in the aftermath of the Early Cambrian extinction event

    Science.gov (United States)

    Hong, Jongsun; Cho, Seong-Hyeon; Choh, Suk-Joo; Woo, Jusun; Lee, Dong-Jin

    2012-05-01

    Numerous decimetre- to metre-scale carbonate buildups dominated by siliceous sponges and the calcimicrobe Epiphyton are reported from the Middle Cambrian (Series 3) Daegi Formation of Korea. These siliceous sponge-Epiphyton buildups consist predominantly of grey micritic boundstones with dark clots and/or white clumps. The boundstones contain sponge spicule networks interpreted as the calcified remains of siliceous sponges. The white clumps and dark clots in the boundstones represent variously preserved Epiphyton. Siliceous sponges form constructional pore space and are commonly encrusted by Epiphyton. The sponges were probably the primary frame-builders, providing substrates for the attachment and subsequent growth of Epiphyton. Epiphyton is considered to be a binder when covering the surface of siliceous sponges, and a subordinate frame-builder when filling depositional voids created by siliceous sponges or growing on top of other Epiphyton growth bundles. The siliceous sponge-Epiphyton buildups of the Daegi Formation show similarities to previously described Late Cambrian (Furongian) anthaspidellid-calcimicrobe buildups from Iran and the USA. Together with recently reported examples from the Zhangxia Formation of eastern China, the sponge-Epiphyton buildups from Korea represent some of the oldest metazoan-calcimicrobe buildups, after the extinction of most archaeocyaths at the end of the Early Cambrian (Series 2). This implies that the incorporation of metazoans in Middle Cambrian (Series 3) carbonate buildups occurred much earlier than previously known. The buildup-forming siliceous sponges described in this study demonstrate that their role in Early Phanerozoic carbonate buildups has been grossly underestimated.

  16. Efforts to control radiation build-up in Ringhals

    Energy Technology Data Exchange (ETDEWEB)

    Egner, K.; Aronsson, P.O.; Erixon, O. [Vattenfall AB, Vaeroebacka (Sweden)

    1995-03-01

    It is well known that good control of the primary chemistry in a PWR is essential in order to minimize material problems and fuel damages. It has also been well established that the water chemistry has a great influence on accumulation of corrosion products on the fuel and the radiation build-up on primary system surfaces. Ringhals was one of the pioneers to increase operating pH in order to reduce radiation build-up and has now been operating for ten years with pH at 7.4 or (in later years) 7.2. Our experience is favourable and includes low radiation levels in the new (1989) steam generators of Ringhals 2. Ringhals 4 has operated almost its whole life at pH 7.2 or higher and it remains one of the cleanest PWRs of its vintage. In addition to strict adherence to a stable operating chemistry, Ringhals is now working on a program with the aim to find optimum shut-down and start-up chemistry to reduce activity levels in the primary systems. A particular goal is to use the shut-down and start-up chemistry at the 1994 outage in Ringhals 3 in order to reduce doserates in preparation for the planned steam generator replacement in 1995. The paper summarizes the experience to date of the established operating chemistry, on-going tests with modified shut-down and start-up chemistry and other measures to limit or reduce the activity build-up.

  17. Humidity Buildup in Electronic Enclosures Exposed to Constant Conditions

    DEFF Research Database (Denmark)

    Conseil, Helene; Staliulionis, Zygimantas; Jellesen, Morten Stendahl

    2017-01-01

    Electronic components and devices are exposed to a wide variety of climatic conditions, therefore the protection of electronic devices from humidity is becoming a critical factor in the system design. The ingress of moisture into typical electronic enclosures has been studied with defined...... parameters such as openings in the enclosure (drain holes, intentional openings or leak) and sealing and casing material. Related corrosion reliability issues due to humidity buildup have been evaluated using an interdigitated surface insulation resistance pattern placed inside the enclosure during exposure...

  18. Energy buildup in sheared force-free magnetic fields

    Science.gov (United States)

    Wolfson, Richard; Low, Boon C.

    1992-01-01

    Photospheric displacement of the footpoints of solar magnetic field lines results in shearing and twisting of the field, and consequently in the buildup of electric currents and magnetic free energy in the corona. The sudden release of this free energy may be the origin of eruptive events like coronal mass ejections, prominence eruptions, and flares. An important question is whether such an energy release may be accompanied by the opening of magnetic field lines that were previously closed, for such open field lines can provide a route for matter frozen into the field to escape the sun altogether. This paper presents the results of numerical calculations showing that opening of the magnetic field is permitted energetically, in that it is possible to build up more free energy in a sheared, closed, force-free magnetic field than is in a related magnetic configuration having both closed and open field lines. Whether or not the closed force-free field attains enough energy to become partially open depends on the form of the shear profile; the results presented compare the energy buildup for different shear profiles. Implications for solar activity are discussed briefly.

  19. Electron-Cloud Build-Up: Theory and Data

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M. A.

    2010-10-08

    We present a broad-brush survey of the phenomenology, history and importance of the electron-cloud effect (ECE). We briefly discuss the simulation techniques used to quantify the electron-cloud (EC) dynamics. Finally, we present in more detail an effective theory to describe the EC density build-up in terms of a few effective parameters. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire 'ECLOUD' series. In addition, the proceedings of the various flavors of Particle Accelerator Conferences contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC.

  20. Damage buildup and edge dislocation mobility in equiatomic multicomponent alloys

    Science.gov (United States)

    Granberg, F.; Djurabekova, F.; Levo, E.; Nordlund, K.

    2017-02-01

    A new class of single phase metal alloys of equal atomic concentrations has shown very promising mechanical properties and good corrosion resistance. Moreover, a significant reduction in damage accumulation during prolonged irradiation has also been observed in these equiatomic multicomponent alloys. A comparison of elemental Ni with the two component NiFe- and the three component NiCoCr-alloy showed a substantial reduction in damage in both alloys, and an even larger difference was seen if only larger clusters were considered. One of the factors limiting the damage build-up in the alloys compared to the elemental material was seen to be dislocation mobility (Granberg et al., 2016). In this Article, we focus on a more thorough investigation of the mobility of edge dislocations in different cases of the Ni-, NiFe- and NiCoCr-samples. We find that even though the saturated amount of defects in the alloys is lower than in elemental Ni, the defect buildup in the early stages is faster in the alloys. We also find that the dislocation mobility in NiFe is lower than in Ni, at low stresses, and that the onset stress in NiFe is higher than in Ni. The same phenomenon was seen in comparison between NiFe and NiCoCr, since the three component alloy had lower dislocation mobility and higher onset stress. The dislocation velocity in elemental Ni plateaued out just under the forbidden velocity, whereas the alloys showed a more complex behaviour.

  1. Investigating the build-up of precedence effect using reflection masking

    DEFF Research Database (Denmark)

    Hartcher-O'Brien, Jessica; Buchholz, Jörg

    2006-01-01

    The auditory processing level involved in the build-up of precedence [Freyman et al., J. Acoust. Soc. Am. 90, 874–884 (1991)] has been investigated here by employing reflection masked threshold (RMT) techniques. Given that RMT techniques are generally assumed to address lower levels of the auditory...... signal processing, such an approach represents a bottom-up approach to the buildup of precedence. Three conditioner configurations measuring a possible buildup of reflection suppression were compared to the baseline RMT for four reflection delays ranging from 2.5–15 ms. No buildup of reflection...

  2. Contour Crafting Simulation Plan for Lunar Settlement Infrastructure Build-Up Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Economically viable and reliable building systems and tool sets are being sought, examined, and tested for extraterrestrial habitat and infrastructure buildup. This...

  3. Process variability of pollutant build-up on urban road surfaces.

    Science.gov (United States)

    Wijesiri, Buddhi; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

    2015-06-15

    Knowledge of the pollutant build-up process is a key requirement for developing stormwater pollution mitigation strategies. In this context, process variability is a concept which needs to be understood in-depth. Analysis of particulate build-up on three road surfaces in an urban catchment confirmed that particles 150 μm have characteristically different build-up patterns, and these patterns are consistent over different field conditions. Three theoretical build-up patterns were developed based on the size-fractionated particulate build-up patterns, and these patterns explain the variability in particle behavior and the variation in particle-bound pollutant load and composition over the antecedent dry period. Behavioral variability of particles build-up process variability. As characterization of process variability is particularly important in stormwater quality modeling, it is recommended that the influence of behavioral variability of particles build-up should be specifically addressed. This would eliminate model deficiencies in the replication of the build-up process and facilitate the accounting of the inherent process uncertainty, and thereby enhance the water quality predictions. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Optimum Water Chemistry in radiation field buildup control

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chien, C. [Vallecitos Nuclear Center, Pleasanton, CA (United States)

    1995-03-01

    Nuclear utilities continue to face the challenGE of reducing exposure of plant maintenance personnel. GE Nuclear Energy has developed the concept of Optimum Water Chemistry (OWC) to reduce the radiation field buildup and minimize the radioactive waste production. It is believed that reduction of radioactive sources and improvement of the water chemistry quality should significantly reduce both the radiation exposure and radwaste production. The most important source of radioactivity is cobalt and replacement of cobalt containing alloy in the core region as well as in the entire primary system is considered the first priority to achieve the goal of low exposure and minimized waste production. A plant specific computerized cobalt transport model has been developed to evaluate various options in a BWR system under specific conditions. Reduction of iron input and maintaining low ionic impurities in the coolant have been identified as two major tasks for operators. Addition of depleted zinc is a proven technique to reduce Co-60 in reactor water and on out-of-core piping surfaces. The effect of HWC on Co-60 transport in the primary system will also be discussed.

  5. The Mechanism for the Energy Buildup Driving Solar Eruptive Events

    Science.gov (United States)

    Knizhnik, K. J.; Antiochos, S. K.; DeVore, C. R.; Wyper, P. F.

    2017-12-01

    The underlying origin of solar eruptive events (SEEs), ranging from giant coronal mass ejections to small coronal-hole jets, is that the lowest-lying magnetic flux in the Sun’s corona undergoes continual buildup of stress and free energy. This magnetic stress has long been observed as the phenomenon of “filament channels:” strongly sheared magnetic field localized around photospheric polarity inversion lines. However, the mechanism for the stress buildup—the formation of filament channels—is still debated. We present magnetohydrodynamic simulations of a coronal volume that is driven by transient, cellular boundary flows designed to model the processes by which the photosphere drives the corona. The key feature of our simulations is that they accurately preserve magnetic helicity, the topological quantity that is conserved even in the presence of ubiquitous magnetic reconnection. Although small-scale random stress is injected everywhere at the photosphere, driving stochastic reconnection throughout the corona, the net result of the magnetic evolution is a coherent shearing of the lowest-lying field lines. This highly counterintuitive result—magnetic stress builds up locally rather than spreading out to attain a minimum energy state—explains the formation of filament channels and is the fundamental mechanism underlying SEEs. Furthermore, this process is likely to be relevant to other astrophysical and laboratory plasmas.

  6. Characterizing polycyclic aromatic hydrocarbon build-up processes on urban road surfaces.

    Science.gov (United States)

    Liu, Liang; Liu, An; Li, Dunzhu; Zhang, Lixun; Guan, Yuntao

    2016-07-01

    Reliable prediction models are essential for modeling pollutant build-up processes on urban road surfaces. Based on successive samplings of road deposited sediments (RDS), this study presents empirical models for mathematical replication of the polycyclic aromatic hydrocarbon (PAH) build-up processes on urban road surfaces. The contaminant build-up behavior was modeled using saturation functions, which are commonly applied in US EPA's Stormwater Management Model (SWMM). Accurate fitting results were achieved in three typical urban land use types, and the applicability of the models was confirmed based on their acceptable relative prediction errors. The fitting results showed high variability in PAH saturation value and build-up rate among different land use types. Results of multivariate data and temporal-based analyses suggested that the quantity and property of RDS significantly influenced PAH build-up. Furthermore, pollution sources, traffic parameters, road surface conditions, and sweeping frequency could synthetically impact the RDS build-up and RDS property change processes. Thus, changes in these parameters could be the main reason for variations in PAH build-up in different urban land use types. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Water sorption and solubility of core build-up materials.

    Science.gov (United States)

    Zankuli, M A; Devlin, H; Silikas, N

    2014-12-01

    To investigate the variation in water sorption and solubility across a range of different core build-up materials. Five materials were tested, four of which are resin-based materials (Grandio Core, Core.X Flow, Bright Flow Core, Speedee) and one resin-modified glass ionomer (Fuji II LC). All specimens (n=10) were immersed in 10ml distilled water in individual glass containers and weighed at one week, 14 and 28 days. After a total immersion time of 28 days, 7 specimens were dried to a constant mass, in a desiccator for 28 days. Three samples of each material were not dried, but were left in distilled water for 1 year, to determine the long-term water sorption properties. Specimens were weighed at monthly intervals until 6 months and then at the 9th and 12th months. Each specimen was measured using a digital electronic caliper (Mitutoyo Corporation, Japan). After 28 days immersion, the change in water sorption and solubility of the materials ranged from 12.9 to 67.1μg/mm(3) (P<0.001) and 0.9-6.4μg/mm(3) respectively (P<0.001). Except for Fuji II LC, an independent T-test showed significantly higher water sorption and solubility for the other materials after 1-year total immersion in water compared to 1 month (P<0.05). Using repeated measures ANOVA, all materials showed mass changes over time (1 month) (P<0.001). Grandio Core had the lowest water sorption and solubility among the tested materials. According to the ISO 4049 standards, all the tested materials showed acceptable water sorption and solubility, apart from the water sorption behavior of Fuji II LC. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  8. Energy absorption buildup factors for thermoluminescent dosimetric materials and their tissue equivalence

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2010-01-01

    Gamma ray energy-absorption buildup factors were computed using the five-parameter geometric progression (G-P) fitting formula for seven thermoluminescent dosimetric (TLD) materials in the energy range 0.015-15 MeV, and for penetration depths up to 40 mfp (mean free path). The generated energy......-absorption buildup factor data have been studied as a function of penetration depth and incident photon energy. Buildup factors determined in the present work should be useful in radiation dosimetry, diagnostics and therapy. The tissue equivalence of TLD materials is also discussed....

  9. Study of influence of buildup factor form on simulated radiographic image

    Directory of Open Access Journals (Sweden)

    Marinković Predrag

    2009-01-01

    Full Text Available The objective of the study presented in this paper is the analysis of influence of different buildup factor forms on a simulated radiographic image. Simulated radiographic images are obtained by means of the ray-tracing technique. Scattered photons are modelled using the generally accepted geometric progression form, linear form and tabulated data of buildup factors. Simulated images were compared to the reference results obtained by Monte Carlo calculation. The best agreement to Monte Carlo simulated images is achieved for the geometric progression form of buildup factor.

  10. Opacity Build-up in Impulsive Relativistic Sources

    Energy Technology Data Exchange (ETDEWEB)

    Granot, Jonathan; Cohen-Tanugi, Johann; Silva, Eduardo do Couto e

    2007-09-28

    Opacity effects in relativistic sources of high-energy gamma-rays, such as gamma-ray bursts (GRBs) or Blazars, can probe the Lorentz factor of the outflow as well as the distance of the emission site from the source, and thus help constrain the composition of the outflow (protons, pairs, magnetic field) and the emission mechanism. Most previous works consider the opacity in steady state. Here we study the effects of the time dependence of the opacity to pair production ({gamma}{gamma} {yields} e{sup +}e{sup -}) in an impulsive relativistic source, which may be relevant for the prompt gamma-ray emission in GRBs or flares in Blazars. We present a simple, yet rich, semi-analytic model for the time and energy dependence of the optical depth, {tau}{gamma}{gamma}, in which a thin spherical shell expands ultra-relativistically and emits isotropically in its own rest frame over a finite range of radii, R{sub 0} {le} R {le} R{sub 0}+{Delta}R. This is particularly relevant for GRB internal shocks. We find that in an impulsive source ({Delta}R {approx}< R{sub 0}), while the instantaneous spectrum (which is typically hard to measure due to poor photon statistics) has an exponential cutoff above the photon energy {var_epsilon}1(T) where t{gamma}{gamma}({var_epsilon}1) = 1, the time integrated spectrum (which is easier to measure) has a power-law high-energy tail above the photon energy {var_epsilon}1* {approx} {var_epsilon}1({Delta}T) where {Delta}T is the duration of the emission episode. Furthermore, photons with energies {var_epsilon} > {var_epsilon}1* are expected to arrive mainly near the onset of the spike in the light curve or flare, which corresponds to the short emission episode. This arises since in such impulsive sources it takes time to build-up the (target) photon field, and thus the optical depth {tau}{gamma}{gamma}({var_epsilon}) initially increases with time and {var_epsilon}1(T) correspondingly decreases with time, so that photons of energy {var_epsilon} > {var

  11. Build-up of insect pests and their natural enemies on rotated and ...

    African Journals Online (AJOL)

    Build-up of insect pests and their natural enemies on rotated and non-rotated okra ( Abelmoschus esculentus (L.) Moench), tomato ( Lycopersicon esculentus Mill) and egg plant ( Solanum melongena (L.) Moench.) fields.

  12. Clinical comparison of various esthetic restorative options for coronal build-up of primary anterior teeth

    National Research Council Canada - National Science Library

    Duhan, Himanshu; Pandit, Inder Kumar; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika; Kochhar, Gulsheen Kaur

    2015-01-01

    This study was designed to compare the clinical performance of composite, strip crowns, biological restoration, and composite with stainless steel band when used for the coronal build-up of anterior teeth...

  13. PREDICTING THE BUILDUP OF POLLUTANT CONCENTRATIONS USING EPA'S VISUAL PLUMES MODEL

    Science.gov (United States)

    Anthropogenic sources contribute pollutants to estuaries that are significantly influenced by tides, frequently exhibiting velocity reversals. Flow reversals, even in the absence of diffusion, can cause a buildup of pollution from a particular discharge in the receiving water. ...

  14. Effects of Fallow Genealogical Cycles on the Build-up of Nutrients in ...

    African Journals Online (AJOL)

    Dr Osondu

    which helped to conserve and build-up essential nutrients in the soil by minimizing the loss of nutrients ... The study suggested that for efficient conservation practices, fallow land mostly the ...... of Agroforestry Systems to Improve Human.

  15. The effect of stimulus context on the buildup to stream segregation

    Directory of Open Access Journals (Sweden)

    Jonathan eSussman-Fort

    2014-04-01

    Full Text Available Stream segregation is the process by which the auditory system disentangles the mixture of sound inputs into discrete sources that cohere across time. The length of time required for this to occur is termed the ‘buildup’ period. In the current study, we used the buildup period as an index of how quickly sounds are segregated into constituent parts. Specifically, we tested the hypothesis that stimulus context impacts the timing of the buildup and, therefore, affects when stream segregation is detected. To measure the timing of the buildup we recorded the Mismatch Negativity component (MMN of event-related brain potentials (ERPs, during passive listening, to determine when the streams were neurophysiologically segregated. In each condition, a pattern of repeating low (L and high (H tones (L-L-H was presented in trains of stimuli separated by silence, with the H tones forming a simple intensity oddball paradigm and the L tones serving as distractors. To determine the timing of the buildup, probe tones occurred in two positions of the trains, early (within the buildup period and late (past the buildup period. The context was manipulated by presenting roving versus non-roving frequencies across trains in two conditions. MMNs were elicited by intensity probe tones in the Non-Roving condition (early and late positions and the Roving condition (late position only indicating that neurophysiologic segregation occurred faster in the Non-Roving condition. This suggests a shorter buildup period when frequency was repeated from train to train. Overall, our results demonstrate that the dynamics of the environment influence the way in which the auditory system extracts regularities from the input. The results support the hypothesis that the buildup to segregation is highly dependent upon stimulus context and that the auditory system works to maintain a consistent representation of the environment when no new information suggests that reanalyzing the scene

  16. Ranking the factors influencing polycyclic aromatic hydrocarbons (PAHs) build-up on urban roads.

    Science.gov (United States)

    Liu, An; Ma, Yukun; Deilami, Kaveh; Egodawatta, Prasanna; Goonetilleke, Ashantha

    2017-05-01

    An in-depth understanding of polycyclic aromatic hydrocarbons (PAHs) build-up on urban roads is essential for effective stormwater treatment design. Past research studies have pointed out the relationship between influential factors and PAHs build-up individually. However, these studies do not provide a comprehensive analysis of the relationships and the hierarchy of factors in terms of their importance in influencing PAHs build-up. This paper presents the outcomes of an in-depth investigation into the range of influential factors, including traffic volume, land use, distance to highway and roughness of road surfaces by ranking them in terms of their influence on PAHs build-up. A number of data analysis techniques including forward stepwise linear regression (FSWLR), principal component analysis (PCA) and multiple linear regression (MLR) were employed for the analyses undertaken. The outcomes confirmed that traffic volume is ranked first while land use and roughness of road surfaces are second and the third, respectively. Distance to highway did not show a significant influence on PAHs build-up. Additionally, it was noted that a high traffic volume tended to produce high loads of PAHs with more than 4 rings and the spatial variability of PAHs build-up were relatively higher in high traffic volume areas. These outcomes contributed to the formulation of a robust stormwater treatment strategy and generation of priority area maps focusing on the removal of PAHs. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Analysis of the build-up of semi and non volatile organic compounds on urban roads.

    Science.gov (United States)

    Mahbub, Parvez; Ayoko, Godwin A; Goonetilleke, Ashantha; Egodawatta, Prasanna

    2011-04-01

    Vehicular traffic in urban areas may adversely affect urban water quality through the build-up of traffic generated semi and non volatile organic compounds (SVOCs and NVOCs) on road surfaces. The characterisation of the build-up processes is the key to developing mitigation measures for the removal of such pollutants from urban stormwater. An in-depth analysis of the build-up of SVOCs and NVOCs was undertaken in the Gold Coast region in Australia. Principal Component Analysis (PCA) and Multicriteria Decision tools such as PROMETHEE and GAIA were employed to understand the SVOC and NVOC build-up under combined traffic scenarios of low, moderate, and high traffic in different land uses. It was found that congestion in the commercial areas and use of lubricants and motor oils in the industrial areas were the main sources of SVOCs and NVOCs on urban roads, respectively. The contribution from residential areas to the build-up of such pollutants was hardly noticeable. It was also revealed through this investigation that the target SVOCs and NVOCs were mainly attached to particulate fractions of 75-300 μm whilst the redistribution of coarse fractions due to vehicle activity mainly occurred in the >300 μm size range. Lastly, under combined traffic scenario, moderate traffic with average daily traffic ranging from 2300 to 5900 and average congestion of 0.47 were found to dominate SVOC and NVOC build-up on roads. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Analysis of build-up of heavy metals and volatile organics on urban roads in gold coast, Australia.

    Science.gov (United States)

    Mahbub, Parvez; Goonetilleke, Ashantha; Ayoko, Godwin A; Egodawatta, Prasanna; Yigitcanlar, Tan

    2011-01-01

    Urban water quality can be significantly impaired by the build-up of pollutants such as heavy metals and volatile organics on urban road surfaces due to vehicular traffic. Any control strategy for the mitigation of traffic related build-up of heavy metals and volatile organic pollutants should be based on the knowledge of their build-up processes. In the study discussed in this paper, the outcomes of a detailed experimental investigation into build-up processes of heavy metals and volatile organics are presented. It was found that traffic parameters such as average daily traffic, volume over capacity ratio and surface texture depth had similar strong correlations with the build-up of heavy metals and volatile organics. Multicriteria decision analyses revealed that that the 1-74 microm particulate fraction of total suspended solids (TSS) could be regarded as a surrogate indicator for particulate heavy metals in build-up and this same fraction of total organic carbon could be regarded as a surrogate indicator for particulate volatile organics build-up. In terms of pollutants affinity, TSS was found to be the predominant parameter for particulate heavy metals build-up and total dissolved solids was found to be the predominant parameter for the potential dissolved particulate fraction in heavy metals buildup. It was also found that land use did not play a significant role in the build-up of traffic generated heavy metals and volatile organics.

  19. Characterizing heavy metal build-up on urban road surfaces: Implication for stormwater reuse

    Energy Technology Data Exchange (ETDEWEB)

    Liu, An [Research Centre of Environmental Engineering and Management, Graduate School at Shenzhen, Tsinghua University, 518055 Shenzhen (China); Cooperative Research and Education Centre for Environmental Technology, Kyoto University–Tsinghua University, 518055 Shenzhen (China); Liu, Liang; Li, Dunzhu [Research Centre of Environmental Engineering and Management, Graduate School at Shenzhen, Tsinghua University, 518055 Shenzhen (China); Guan, Yuntao, E-mail: guanyt@tsinghua.edu.cn [Research Centre of Environmental Engineering and Management, Graduate School at Shenzhen, Tsinghua University, 518055 Shenzhen (China); School of Environment, Tsinghua University, Beijing 100084 (China)

    2015-05-15

    Stormwater reuse is increasingly popular in the worldwide. In terms of urban road stormwater, it commonly contains toxic pollutants such as heavy metals, which could undermine the reuse safety. The research study investigated heavy metal build-up characteristics on urban roads in a typical megacity of South China. The research outcomes show the high variability in heavy metal build-up loads among different urban road sites. The degree of traffic congestion and road surface roughness was found to exert a more significant influence on heavy metal build-up rather than traffic volume. Due to relatively higher heavy metal loads, stormwater from roads with more congested traffic conditions or rougher surfaces might be suitable for low-water-quality required activities while the stormwater from by-pass road sections could be appropriate for relatively high-water-quality required purposes since the stormwater could be relatively less polluted. Based on the research outcomes, a decision-making process for heavy metals based urban road stormwater reuse was proposed. The new finding highlights the importance to undertaking a “fit-for-purpose” road stormwater reuse strategy. Additionally, the research results can also contribute to enhancing stormwater reuse safety. - Highlights: • Heavy metal (HM) build-up varies with traffic and road surface conditions. • Traffic congestion and surface roughness exert a higher impact on HM build-up. • A “fit-for-purpose” strategy could suit urban road stormwater reuse.

  20. Contour Crafting Simulation Plan for Lunar Settlement Infrastructure Build-Up

    Science.gov (United States)

    Khoshnevis, B.; Carlson, A.; Leach N.; Thangavelu, M.

    2016-01-01

    Economically viable and reliable building systems and tool sets are being sought, examined and tested for extraterrestrial infrastructure buildup. This project focused on a unique architecture weaving the robotic building construction technology with designs for assisting rapid buildup of initial operational capability Lunar and Martian bases. The project aimed to study new methodologies to construct certain crucial infrastructure elements in order to evaluate the merits, limitations and feasibility of adapting and using such technologies for extraterrestrial application. Current extraterrestrial settlement buildup philosophy holds that in order to minimize the materials needed to be flown in, at great transportation costs, strategies that maximize the use of locally available resources must be adopted. Tools and equipment flown as cargo from Earth are proposed to build required infrastructure to support future missions and settlements on the Moon and Mars.

  1. Change in surface SP caused by pressure buildup observed at the Nigorikawa geothermal area; Nigorikawa chiiki ni okeru atsuryoku buildup ji no shizen den`i henka

    Energy Technology Data Exchange (ETDEWEB)

    Yasukawa, K.; Yano, Y.; Matsushima, N.; Ishido, T. [Geological Survey of Japan, Tsukuba (Japan); Takahashi, M.; Suzuki, I.; Aoyama, K.; Kuwano, T.

    1996-10-01

    To examine the effect of change of subsurface flow system on the surface SP (self potential), SP measurements were carried out before and after the pressure buildup and drawdown during the periodic inspection at Nigorikawa area. Relation between the SP distribution and the observed data was also examined by 2-D numerical simulation. Tendency was found that the SP increased gradually with the production near the production well, decreased during the pressure buildup, and increased again during the drawdown. There were some points having the reverse tendency in the surrounding area. Behavior during the pressure buildup and drawdown was not clear. The resistivity near the ground surface was low ranging between 2 and 5 ohm/m within the Nigorikawa basin. The variation of SP was not so large when compared with the measuring error. The SP profiles on the secondary section passing in the center of caldera at the production stop and at one week after the production start were well corresponded with the profiles under natural conditions which were reproduces using the 2-D model. It was considered that the SP profile before the production stop was affected by the production. 12 refs., 6 figs., 1 tab.

  2. Exposure Buildup Factors for Heavy Metal Oxide Glass: A Radiation Shield

    DEFF Research Database (Denmark)

    Manonara, S. R.; Hanagodimath, S. M.; Gerward, Leif

    2011-01-01

    Gamma ray exposure buildup factors for three Heavy Metal Oxide (HMO) glass systems, viz. PbO-Bi2O3-B2O3, PbO-B2O3, and Bi2O3-B2O3 glasses are presented. The computations were done by interpolation method using the Geometric Progression fitting formula and ANSI/ANS-6.4.3 library for the energy range...... of graphs. Buildup factors of these HMO glasses cannot be found in any standard database, but they are useful for practical calculations in gamma ray shield designs, and they also, help to determine and control the thickness of the shielding material used....

  3. Effects of Fallow Genealogical Cycles on the Build-up of Nutrients in ...

    African Journals Online (AJOL)

    The study examined the effect of fallow generational cycles on the buildup of nutrients in the soil. Fallow sequence of 1st, 2nd, 3rd, 4th and 5th generations were studied. The quadrat approach of sampling was employed to collect soil samples (surface and subsurface) from five plots of 10m x 10m across the five fallow ...

  4. Finite and infinite system gamma ray buildup factor calculations with detailed physics.

    Science.gov (United States)

    Atak, Haluk; Çelikten, Osman Şahin; Tombakoğlu, Mehmet

    2015-11-01

    Examination of physical interactions of photons in materials is a significant subject for buildup factor studies. In most of the buildup calculations, by default, coherent (Rayleigh) scattering is ignored and the Compton scattering is modeled by free-electron Klein-Nishina formula with "simple physics" treatment. In this work, photon buildup factors are calculated for many different cases including "detailed physics" by taking into account coherent and bound-electron Compton scatterings with the Monte Carlo code, MCNP5, and the results are compared with the literature values. They are computed for point isotropic photon sources up to depths of 20 mean free paths and at the three photon energies most widely used (0.06, 0.6 and 6MeV). Calculations are made for both finite and infinite homogeneous ordinary water media. It is concluded that Coherent scattering is very dominant at low energies and for deep penetrations and assumed physical approximation (simple/detailed, finite/infinite) is the critical point for determining shielding material dimensions. After all, it can be stated that all parametric assumptions should be clearly given and indicated in the tabulation of photon buildup factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Effect of sodium hypochlorite contamination on microhardness of dental core build-up materials.

    Science.gov (United States)

    Wegehaupt, Florian Just; Betschart, Jasmin; Attin, Thomas

    2010-08-01

    This study aimed to determine the influence of sodium hypochlorite (NaOCl) contamination on the microhardness of build-up composites. Fifty-two samples, from each of three build-up materials (LuxaCore Dual, MultiCore flow and Rebilda DC) were prepared. Half of the samples from each material were stored in physiologic saline (baseline control) while the other halves were stored in NaOCl. After 1 h, the samples were rinsed with tap water, cut axially and measured for Knoop hardness at different depth levels. The results were analysed by ANOVA and unpaired t-tests (pmicrohardness were observed for LuxaCore Dual up to 0.2 mm, Rebilda DC up to 0.3 mm, and for MultiCore flow up to 0.4 mm under the surface level. Contact with sodium hypochlorite on build-up materials causes reduction of the microhardness. The softening is not only limited on the surface, but can also be found in deeper layers of build-up materials.

  6. Slow build-up of cochlear suppression during sustained contralateral noise: central modulation of olivocochlear efferents?

    Science.gov (United States)

    Larsen, Erik; Liberman, M. Charles

    2009-01-01

    The strength of the medial olivocochlear (OC) reflex is routinely assayed by measuring suppression of ipsilateral responses such as otoacoustic emissions (OAEs) by a brief contralateral noise, e.g. (Berlin et al., 1995). Here, we show in anesthetized guinea pigs, that the magnitude of OC-mediated suppression of ipsilateral cochlear responses (i.e. compound actions potentials (CAPs), distortion product (DP) OAEs and round-window noise) slowly builds over 2–3 minutes during a sustained contralateral noise. The magnitude of this build-up suppression was largest at low ipsilateral stimulus intensities, as seen for suppression measured at contra-noise onset. However, as a function of stimulus frequency, build-up suppression magnitude was complementary to onset suppression, i.e. largest at the lowest and highest frequencies tested. Both build-up and onset suppression were eliminated by cutting the OC bundle. In contrast to “slow effects” of shock-evoked medial OC activity (Sridhar et al., 1995), which are mediated by slow intracellular changes in Ca concentration in OHCs, build-up effects of contralateral noise are immediately extinguished upon OC bundle transection and are likely mediated by central modulation of the response rates in MOC fibers due to the sustained noise. Results suggest that conventional tests of OC reflex strength may underestimate its magnitude in noisy environments. PMID:19232534

  7. Influence of pollutant build-up on variability in wash-off from urban road surfaces.

    Science.gov (United States)

    Wijesiri, Buddhi; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

    2015-09-15

    Variability in the pollutant wash-off process is a concept which needs to be understood in-depth in order to better assess the outcomes of stormwater quality models, and thereby strengthen stormwater pollution mitigation strategies. Current knowledge about the wash-off process does not extend to a clear understanding of the influence of the initially available pollutant build-up on the variability of the pollutant wash-off load and composition. Consequently, pollutant wash-off process variability is poorly characterised in stormwater quality models, which can result in inaccurate stormwater quality predictions. Mathematical simulation of particulate wash-off from three urban road surfaces confirmed that the wash-off load of particle size fractions 150 μm after a storm event vary with the build-up of the respective particle size fractions available at the beginning of the storm event. Furthermore, pollutant load and composition associated with the initially available build-up of build-up of pollutants associated with > 150 μm particles on wash-off process variability is significant only for relatively shorter duration storm events. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. "Testing during Study Insulates against the Buildup of Proactive Interference": Correction

    Science.gov (United States)

    Szpunar, Karl K.; McDermott, Kathleen B.; Roedigger, Henry L., III

    2009-01-01

    Reports an error in "Testing during study insulates against the buildup of proactive interference" by Karl K. Szpunar, Kathleen B. McDermott and Henry L. Roediger III ("Journal of Experimental Psychology: Learning, Memory, and Cognition," 2008[Nov], Vol 34[6], 1392-1399). Incorrect figures were printed due to an error in the…

  9. On the reversibility of cake buildup and compression in a membrane bioreactor

    DEFF Research Database (Denmark)

    Jørgensen, Mads Koustrup; Keiding, Kristian; Christensen, Morten Lykkegaard

    2014-01-01

    Fouling in a membrane bioreactor was studied by describing the reversibility of fouling developing during short-term experiments. Data were fitted to a recently proposed model of the buildup and compression of fouling layers. Shear stepping experiments performed to characterize the efficiency...

  10. Effects of Fallow Genealogical Cycles on the Build-up of Nutrients in ...

    African Journals Online (AJOL)

    Dr Osondu

    Abstract. The study examined the effect of fallow generational cycles on the buildup of nutrients in the soil. Fallow sequence of 1st, 2nd, 3rd, 4th and 5th generations were studied. The quadrat approach of sampling was employed to collect soil samples (surface and subsurface) from five plots of 10m x 10m across the five.

  11. Effect of heat build-up on carbon emissions in chimato compost piles ...

    African Journals Online (AJOL)

    A study was conducted to determine impacts of heat build-up of chimato compost piles TD0, TD20, TD40, TD50, TD60, TD80 and TD100, made by blending maize stalks with 0, 20, 40, 50, 60, 80 and 100% Tithonia diversifolia, respectively, on carbon losses and emissions during composting. Compost piles temperatures ...

  12. A study of the build-up region of megavoltage radiation beams

    Science.gov (United States)

    Abdel-Rahman, Wamied

    A phantom-embedded extrapolation chamber (PEEC) made of Solid Water(TM) was used for studying the buildup region of megavoltage radiation beams. We investigated the polarity effect produced in the PEEC and found that radiation induced currents, called the Compton current, were the dominant cause of the polarity effect in the PEEC. In the dose build-up region of megavoltage photon beams, the collecting electrode is the primary Compton current source and the magnitude of the current depends on the measurement depth, field size, and photon beam quality. The connecting cable acts as a secondary Compton current source that produces a very small Compton current which depends on the field size and the photon beam quality, becoming the dominant source when the PEEC is placed at depths greater than the depth of maximum dose. A study of the dose build-up region of megavoltage photon beams showed that the percentage depth ionizations obtained from measurements are higher than the percentage depth doses obtained with Monte Carlo (MC) techniques. To validate the MC-calculated percentage depth doses, the design of the PEEC was incorporated in the simulations. While the MC-calculated and measured percentage depth ionizations in the dose build-up region agreed with one another for the 6 MV, a non-negligible difference is observed for the 18 MV x-ray beam. A number of experiments and theoretical studies of various possible effects which could be the source of this discrepancy is investigated. We show that the contribution of contaminating neutrons and protons to the doses in the 18 MV x-ray beam is negligible. Moreover, the MC calculations using the XCOM photon cross sections database and the NIST bremsstrahlung differential cross sections do not explain the discrepancy between the MC calculations and measurement in the dose build-up region for the 18 MV and this discrepancy is yet to be further investigated.

  13. Repair bond strength of dual-cured resin composite core buildup materials.

    Science.gov (United States)

    El-Deeb, Heba A; Ghalab, Radwa M; Elsayed Akah, Mai M; Mobarak, Enas H

    2016-03-01

    The reparability of dual-cured resin composite core buildup materials using a light-cured one following one week or three months storage, prior to repair was evaluated. Two different dual-cured resin composites; Cosmecore™ DC automix and Clearfil™ DC automix core buildup materials and a light-cured nanofilled resin composite; Filtek™ Z350 XT were used. Substrate specimens were prepared (n = 12/each substrate material) and stored in artificial saliva at 37 °C either for one week or three months. Afterward, all specimens were ground flat, etched using Scotchbond™ phosphoric acid etchant and received Single Bond Universal adhesive system according to the manufacturers' instructions. The light-cured nanofilled resin composite (Filtek™ Z350 XT) was used as a repair material buildup. To determine the cohesive strength of each solid substrate material, additional specimens from each core material (n = 12) were prepared and stored for the same periods. Five sticks (0.8 ± 0.01 mm(2)) were obtained from each specimen (30 sticks/group) for microtensile bond strength (μTBS) testing. Modes of failure were also determined. Two-way ANOVA revealed a significant effect for the core materials but not for the storage periods or their interaction. After one week, dual-cured resin composite core buildup materials (Cosmecore™ DC and Clearfil™ DC) achieved significantly higher repair μTBS than the light-cured nanofilled resin composite (Filtek™ Z350 XT). However, Clearfil™ DC revealed the highest value, then Cosmecore™ DC and Filtek™ Z350 XT, following storage for 3-month. Repair strength values recovered 64-86% of the cohesive strengths of solid substrate materials. The predominant mode of failure was the mixed type. Dual-cured resin composite core buildup materials revealed acceptable repair bond strength values even after 3-month storage.

  14. Comparing dose in the build-up region between compensator- and MLC-based IMRT.

    Science.gov (United States)

    Javedan, Khosrow; Zhang, Geoffrey G; Hoffe, Sarah; Feygelman, Vladimir; Forster, Kenneth

    2012-09-06

    The build-up dose in the megavoltage photon beams can be a limiting factor in intensity-modulated radiation therapy (IMRT) treatments. Excessive surface dose can cause patient discomfort and treatment interruptions, while underdosing may lead to tumor repopulation and local failure. Dose in the build-up region was investigated for IMRT delivery with solid brass compensator technique(compensator-based IMRT) and compared with that of multileaf collimator (MLC)-based IMRT. A Varian Trilogy linear accelerator equipped with an MLC was used for beam delivery. A special solid brass step-wise compensator was designed and built for testing purposes. Two step-and-shoot MLC fields were programmed to produce a similar modulated step-wise dose profile. The MLC and compensator dose profiles were measured and adjusted to match at the isocenter depth of 10 cm. Build-up dose in the 1-5 mm depth range was measured with an ultrathin window, fixed volume parallel plate ionization chamber. Monte Carlo simulations were used to model the brass compensator and step-and-shoot MLC fields. The measured and simulated profiles for the two IMRT techniques were matched at the isocenter depth of 10 cm. Different component contributions to the shallow dose, including the MLC scatter, were quantified. Mean spectral energies for the open and filtered beams were calculated. The compensator and MLC profiles at 10 cm depth were matched better than ± 1.5%. The build-up dose was up to 7% lower for compensator IMRT compared to MLC IMRT due to beam hardening in the brass. Low-energy electrons contribute 22% and 15% dose at 1 mm depth for compensator and MLC modalities, respectively. Compensator-based IMRT delivers less dose in the build-up region than MLC-based IMRT does, even though a compensator is closer to the skin than the MLC.

  15. Calculation of point isotropic buildup factors of gamma rays for water and lead

    Directory of Open Access Journals (Sweden)

    A. S. H.

    2001-12-01

    Full Text Available   Exposure buildup factors for water and lead have been calculated by the Monte-Carlo method for an isotropic point source in an infinite homogeneous medium, using the latest cross secions available on the Internet. The types of interactions considered are ,photoelectric effect, incoherent (or bound-electron Compton. Scattering, coherent (or Rayleigh scattering and pair production. Fluorescence radiations have also been taken into acount for lead. For each material, calculations were made at 10 gamma ray energies in the 40 keV to 10 MeV range and up to penetration depths of 10 mean free paths at each energy point. The results presented in this paper can be considered as modified gamma ray exposure buildup factors and be used in radiation shielding designs.

  16. Comparative study of mechanical properties of direct core build-up materials

    OpenAIRE

    Kumar, Girish; Shivrayan, Amit

    2015-01-01

    Background and Objectives: The strength greatly influences the selection of core material because core must withstand forces due to mastication and para-function for many years. This study was conducted to evaluate certain mechanical properties of commonly used materials for direct core build-up, including visible light cured composite, polyacid modified composite, resin modified glass ionomer, high copper amalgam, and silver cermet cement. Materials and Methods: All the materials were manipu...

  17. Resin composite build-ups for complementing multidisciplinary esthetic and functional dental treatments: a case report

    OpenAIRE

    Chaves, Larissa Pinceli; Unipar - Universidade Paranaense; Schmitt, Vera Lucia; University of Paraná West – UNIOESTE – Cascavel – PR – Brazil.; Consolgmano, Elaine; Bauru School of Denstistry – University of São Paulo – Bauru – SP – Brazil.; Frenken, Rafael Pedro; Specialist Dental Association – Cascavel – PR – Brazil.; Mondelli, Rafael Francisco Lia; Bauru School of Denstistry – University of São Paulo – Bauru – SP – Brazil.; Wang, Linda; Bauru School of Denstistry – University of São Paulo – Bauru – SP – Brazil.

    2015-01-01

    Discrepancies in tooth shape and placement of the anterior teeth represent uncomfortable esthetic scenario for many patients. Even current composite resin proximal build-up is considered to be practical and conservative, in some cases, interdisciplinary approach with orthodontics optimize functional and esthetic results. This case report describes the management of a patient who complained of lack of anterior esthetic, which compromises her quality of life. The correct diagnosis and the treat...

  18. Step-by-step build-up of covalent poly(ethylene oxide) nanogel films.

    Science.gov (United States)

    Zahouani, S; Hurman, L; De Giorgi, M; Vigier-Carrière, C; Boulmedais, F; Senger, B; Frisch, B; Schaaf, P; Lavalle, P; Jierry, L

    2017-11-30

    Hydrogels based on poly(ethylene glycol) (PEG) are commonly used for studies related to cell fate and tissue engineering. Here we present a new covalent layer-by-layer build-up process leading to PEG coatings of nanometer size called "nanogel films". Compared to macroscopic hydrogels, such nanogels should provide a fine control over the structure and the thickness of the coating. Alternated deposition of bifunctional and tetra functional PEG molecules reacting through thiol/maleimide click chemistry is evaluated by quartz crystal microbalance. We first study parameters influencing the build-up process of such coatings and demonstrate the importance of (i) the nature of the first deposited layer, (ii) the PEG concentrations and (iii) the length of the PEG chains that appears to be the most significant parameter influencing film growth. The build-up process can be extended to a large variety of substrates like SiO2 or polymers by using an appropriate anchoring layer. Covalent functionalization of these nanogel films by proteins or enzymes is suited by modifying the biomolecules with thiol or maleimide groups and immobilizing them during the build-up process. Activity of the embedded enzymes can be maintained. Moreover ligands like biotin can be incorporated into the film and recognition by streptavidin can be modulated by playing with the number of PEG layers covering biotin. Compared to well-known PEG hydrogels, these new coatings are promising as they allow to (i) build thin nanometric coatings, (ii) finely control the amount of deposited PEG and (iii) organize the position of the embedded biomolecules inside the film layers.

  19. Secondary side TSP deposit buildup: lab test investigation focused on electrokinetic considerations

    Energy Technology Data Exchange (ETDEWEB)

    Barale, M.; Guillodo, M.; Foucault, M., E-mail: Morgan.Barale@areva.com [AREVA NP SAS, Technical Centre, Le Creusot (France); Ryckelynck, N.; Clinard, M-H.; Chahma, F.; Brun, C. [AREVA NP SAS, Chemistry and Radiochemistry Group, Paris (France); Corredera, G. [Electricite de France, Centre d' Expertise et d' Inspection dans les domaines de la Realisation et de l' Exploitation, Saint-Denis (France)

    2010-07-01

    Deposit buildup which caused the clogging of the 'foils' of the upper tube-support-plates (TSP) inside a PWR steam generator of French NPPs in 2006 presents certain similarities with deposits observed in lab tests performed in secondary coolant chemistry at the Technical Centre of AREVA NP in 2002. The mechanism of TSP clogging seems not to present obvious phenomenological links with the fouling of the free span of SG since deposits buildup is quite uniform and is currently related to a surface boiling effect due to the surface heat flux. A specific mechanism could account for TSP clogging. In particular, electrokinetic effects were investigated by EDF-CEIDRE and AREVA NP SAS in the framework of a lab test program started in 2007. The electrokinetic approach is to consider that the coupling of local hydrodynamic and surface electrochemistry could lead to the formation of a very localized and heterogeneous deposit at the leading edge between both TSP and SG tubing material. Electrokinetic effects can lead to the oxidation and/or the precipitation of ferrous ions and to a variation of the electrokinetic potential which can produce strong attraction of iron oxide colloids. These electrokinetic effects are dependent of the T/H and local hydrodynamic conditions and surface electrochemistry explaining. The objective of this EDF-AREVA lab test program is to investigate the role of secondary chemistry coolant (pH, DH, N{sub 2}H{sub 4}, amine, redox) and of the nature of materials (SS, Ni base alloy) on deposit buildup. Properties of oxide surface and zeta potential of oxidized metallic materials have been also determined at temperature to understand their potential contribution on mechanism of TSP clogging in secondary side chemistry coolant. In this paper, a set of specific experiments carried out in this frame have been presented and discussed, paying particular attention to the effects of electrokinetic considerations and surface charges at oxide

  20. Build-up dynamics of heavy metals deposited on impermeable urban surfaces.

    Science.gov (United States)

    Wicke, D; Cochrane, T A; O'Sullivan, A

    2012-12-30

    A method using thin boards (3 cm thick, 0.56 m(2)) comprising different paving materials typically used in urban environments (2 asphalt types and concrete) was employed to specifically investigate air-borne deposition dynamics of TSS, zinc, copper and lead. Boards were exposed at an urban car park near vehicular traffic to determine the rate of contaminant build-up over a 13-day dry period. Concentration profiles from simulated rainfall wash-off were used to determine contaminant yields at different antecedent dry days. Maximum contaminant yields after 13 days of exposure were 2.7 kg ha(-1) for TSS, 35 g ha(-1) zinc, 2.3 g ha(-1) copper and 0.4 g ha(-1) lead. Accumulation of all contaminants increased over the first week and levelled off thereafter, supporting theoretical assumptions that contaminant accumulation on impervious surfaces asymptotically approaches a maximum. Comparison of different surface types showed approximately four times higher zinc concentrations in runoff from asphalt surfaces and two times higher TSS concentrations in runoff from concrete, which is attributed to different physical and chemical compositions of the pavement types. Contaminant build-up and wash-off behaviours were modelled using exponential and saturation functions commonly applied in the US EPA's Stormwater Management Model (SWMM) showing good correlation between measured and modelled concentrations. Maximum build-up, half-saturation time, build-up rate constants and wash-off coefficients, necessary for stormwater contaminant modelling, were determined for the four contaminants studied. These parameters are required to model contaminant concentrations in urban runoff assisting in stormwater management decisions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Slow build-up of cochlear suppression during sustained contralateral noise: central modulation of olivocochlear efferents?

    Science.gov (United States)

    Larsen, Erik; Liberman, M Charles

    2009-10-01

    The strength of the medial olivocochlear (OC) reflex is routinely assayed by measuring suppression of ipsilateral responses such as otoacoustic emissions (OAEs) by a brief contralateral noise, e.g., (Berlin, C.I., Hood, L.J., Cecola, P., Jackson, D.F., Szabo, P. 1993. Does type I afferent dysfunction reveal itself through lack of efferent suppression. Hear. Res. 65, 40-50). Here, we show in anesthetized guinea pigs, that the magnitude of OC-mediated suppression of ipsilateral cochlear responses (i.e., compound actions potentials (CAPs), distortion product (DP) OAEs and round-window noise) slowly builds over 2-3 min during a sustained contralateral noise. The magnitude of this build-up suppression was largest at low ipsilateral stimulus intensities, as seen for suppression measured at contra-noise onset. However, as a function of stimulus frequency, build-up suppression magnitude was complementary to onset suppression, i.e., largest at the lowest and highest frequencies tested. Both build-up and onset suppression were eliminated by cutting the OC bundle. In contrast to "slow effects" of shock-evoked medial OC activity (Sridhar, T.S., Liberman, M.C., Brown, M.C., Sewell, W.F. 1995. A novel cholinergic "slow effect" of efferent stimulation on cochlear potentials in the guinea pig. J. Neurosci. 15, 3667-3678), which are mediated by slow intracellular changes in Ca concentration in OHCs, build-up effects of contralateral noise are immediately extinguished upon OC bundle transection and are likely mediated by central modulation of the response rates in MOC fibers due to the sustained noise. Results suggest that conventional tests of OC reflex strength may underestimate its magnitude in noisy environments. 2009 Elsevier B.V.

  2. Shear bond strength of different materials used as core build-up to ceramic.

    Science.gov (United States)

    Lilaj, Bledar; Franz, Alexander; Dangl, Viktoria; Dauti, Rinet; Moritz, Andreas; Cvikl, Barbara

    2017-10-01

    To determine the performance of a resin composite material specially developed for core build-ups in comparison with conventional restorative materials. 90 roughened ceramic blocs were divided into three groups; one group (n=30) was used for the core build-up material (Gradia Core) and the other two groups (n=30, each) were used for two conventional restorative materials (Tetric EvoCeram, Compoglass F). After adhesive fixation, specimens of each material were subdivided in accordance with the storage conditions (thermocycling or water storage). Shear bond strength was measured and fracture behavior was analyzed. Gradia Core presented significantly higher shear bond strength values than the conventional restorative material Tetric EvoCeram, both after 24 hours water storage as well as after thermocycling. Compoglass F did not show any statistically significant differences compared to the other materials, independent of the storage condition. However, Compoglass F resulted in numerically higher shear bond values than Tetric EvoCeram, but lower shear bond values than Gradia Core. Within the same materials, no statistically significant differences occurred regarding the storage conditions. The specific core build-up material provided stronger bonding properties when luted to feldspar ceramic than conventional restorative materials, making it a suitable supporting material when high-quality esthetic restorations are needed for restoring decayed, but vital teeth.

  3. Characterizing heavy metal build-up on urban road surfaces: implication for stormwater reuse.

    Science.gov (United States)

    Liu, An; Liu, Liang; Li, Dunzhu; Guan, Yuntao

    2015-05-15

    Stormwater reuse is increasingly popular in the worldwide. In terms of urban road stormwater, it commonly contains toxic pollutants such as heavy metals, which could undermine the reuse safety. The research study investigated heavy metal build-up characteristics on urban roads in a typical megacity of South China. The research outcomes show the high variability in heavy metal build-up loads among different urban road sites. The degree of traffic congestion and road surface roughness was found to exert a more significant influence on heavy metal build-up rather than traffic volume. Due to relatively higher heavy metal loads, stormwater from roads with more congested traffic conditions or rougher surfaces might be suitable for low-water-quality required activities while the stormwater from by-pass road sections could be appropriate for relatively high-water-quality required purposes since the stormwater could be relatively less polluted. Based on the research outcomes, a decision-making process for heavy metals based urban road stormwater reuse was proposed. The new finding highlights the importance to undertaking a "fit-for-purpose" road stormwater reuse strategy. Additionally, the research results can also contribute to enhancing stormwater reuse safety. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Modelling heavy metals build-up on urban road surfaces for effective stormwater reuse strategy implementation.

    Science.gov (United States)

    Hong, Nian; Zhu, Panfeng; Liu, An

    2017-12-01

    Urban road stormwater is an alternative water resource to mitigate water shortage issues in the worldwide. Heavy metals deposited (build-up) on urban road surface can enter road stormwater runoff, undermining stormwater reuse safety. As heavy metal build-up loads perform high variabilities in terms of spatial distribution and is strongly influenced by surrounding land uses, it is essential to develop an approach to identify hot-spots where stormwater runoff could include high heavy metal concentrations and hence cannot be reused if it is not properly treated. This study developed a robust modelling approach to estimating heavy metal build-up loads on urban roads using land use fractions (representing percentages of land uses within a given area) by an artificial neural network (ANN) model technique. Based on the modelling results, a series of heavy metal load spatial distribution maps and a comprehensive ecological risk map were generated. These maps provided a visualization platform to identify priority areas where the stormwater can be safely reused. Additionally, these maps can be utilized as an urban land use planning tool in the context of effective stormwater reuse strategy implementation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. A simple model of pressure build-up caused by porosity reduction during burial

    Energy Technology Data Exchange (ETDEWEB)

    Wangen, M.

    1997-05-01

    The report relates to a study done on fluid pressure build-up owing to porosity reduction in sedimentary basins during burial. The model assumes that the void ratio decreases exponentially with depth, and that the permeability is proportional to the void ratio to an arbitrary exponent. Simple analytical solutions are obtained for the Darcy velocity and the fluid excess pressure The pressure build-up during burial is studied with these solutions, and it is found to be inversely proportional to the gravity number. The importance of the permeability exponents on the fluid pressure is studied as well. Gravity numbers much less than 1 are shown to yield high access pressures during burial, A reasonable approximation for the maximum Darcy velocity is found to be the product of the surface void ratio and the burial rate. Hydro-fracturing is discussed in relation to the pressure build-up, and cases characterised by gravity numbers much less than 1 are found to yield hydro-fracturing over large depth ranges. It is suggested that the average permeability of hydro-fractured sediments during burial corresponds to the gravity number equal to 1. 28 refs., 8 figs.

  6. Reduction of the Buildup Contribution in Gamma Ray Attenuation Measurements and a New Way to Study This Experiment in a Student Laboratory

    Science.gov (United States)

    Adamides, E.; Kavadjiklis, A.; Koutroubas, S.K.; Moshonas, N.; Tzedakis, A.; Yiasemides, K.

    2014-01-01

    In continuation of our investigation into the buildup phenomenon appearing in gamma ray attenuation measurements in laboratory experiments we study the dependence of the buildup factor on the area of the absorber in an effort to reduce the buildup of photons. Detailed measurements are performed for up to two mean free paths of [superscript 60]Co…

  7. Radiation induced current in the RF coils of integrated linac-MR systems: the effect of buildup and magnetic field.

    Science.gov (United States)

    Burke, Ben; Ghila, Andrei; Fallone, B G; Rathee, Satyapal

    2012-08-01

    In integrated linac-MRI systems, a measurable radiation induced current (RIC) is caused in RF coils by pulsed irradiation. This work (1) tests a buildup method of RIC removal in planar conductors; (2) validates a Monte Carlo method of RIC calculation in metal conductors; and (3) uses the Monte Carlo method to examine the effects of magnetic fields on both planar conductor and practical cylindrical coil geometries. The RIC was measured in copper and aluminum plates, taken as the RF coil conductor surrogates, as a function of increasing thickness of buildup materials (teflon and copper). Based on the Penelope Monte Carlo code, a method of RIC calculation was implemented and validated against measurements. This method was then used to calculate the RIC in cylindrical coil geometries with various air gaps between the coil conductor and the enclosed water phantom. Magnetic fields, both parallel and perpendicular to the radiation beam direction, were then included in the simulation program. The effect of magnetic fields on the effectiveness of RIC removal with the application of buildup material was examined in both the planar and the cylindrical geometries. Buildup reduced RIC in metal plate conductors. For copper detector∕copper buildup case, the RIC amplitude was reduced to zero value with 0.15 cm copper buildup. However, when the copper is replaced with teflon as buildup atop the copper conductor, the RIC was only reduced to 80% of its value at zero buildup since the true electronic equilibrium cannot be obtained in this case. For the aluminum detector∕teflon buildup case, the initial amplitude of the RIC was reduced by 90% and 92% in planar aluminum conductor and a surface coil, respectively. In case of cylindrical coils made of aluminum, teflon buildup around the coil's outer surface was generally effective but failed to remove RIC when there was an air gap between the coil and the phantom. Stronger magnetic fields (>0.5 T) perpendicular to the beam direction

  8. Build-up material requirements in clinical dosimetry during total body irradiation treatments

    Directory of Open Access Journals (Sweden)

    Martin Butson

    2016-01-01

    Full Text Available Total body irradiation (TBI treatments are mainly used in a preparative regimen for hematopoietic stem cell (or bone marrow transplantation. Our standard clinical regimen is a 12 Gy/6 fraction bi-daily technique using 6MV X-rays at a large extended source to surface distance (SSD. This work investigates and quantifies the dose build-up characteristics and thus the requirements for bolus used for in vivo dosimetry for TBI applications. Percentage dose build-up characteristics of photon beams have been investigated at large extended SSDs using ionization chambers and Gafchromic film. Open field measurements at different field sizes and with differing scatter conditions such as the introduction of standard Perspex scattering plates at different distances to the measurement point were made in an effort to determine the required bolus/build-up material required for accurate determination of applied dose. Percentage surface dose values measured for open fields at 300 cm SSD were found to range from 20% up to 65.5% for fields 5 cm × 5 cm to 40 cm × 40 cm, respectively. With the introduction of 1 cm Perspex scattering plates used in TBI treatments, the surface dose values increased up to 83–90% (93–97% at 1 mm depth, depending on the position of the Perspex scattering plate compared to the measurement point. Our work showed that at least 5 mm water equivalent bolus/scatter material should be placed over the EBT3 film for accurate dose assessment for TBI treatments. Results also show that a small but measurable decrease in measured dose occurred with 5 mm water equivalent thick bolus material of areas '3 cm2. As such, we recommend that 3 cm × 3 cm × 5 mm bolus build-up is the smallest size that should be placed over EBT3 Gafchromic film when used for accurate in vivo dosimetry for TBI applications.

  9. Poster - Thur Eve - 56: Verification of buildup region dose calculation of a treatment planning system.

    Science.gov (United States)

    Bassey, B; Sidhu, N

    2012-07-01

    Buildup region dose calculation of Pinnacle3 (version 9.0), a treatment planning system (TPS) commissioned using cylindrical ionization chamber measurements, have been verified experimentally. Dose values measured using Attix parallel plate ionization chamber were compared with those calculated by Pinnacle3 for a variety of clinical setups involving: 6 MV and 15 MV photon beams, open fields, enhanced dynamic wedges, physical wedges, block tray, 85, 100 and 120 cm source-to-surface distances, and square field sizes ranging from 3 × 3 to 30 × 30 cm2 . The dose difference (DD) and distance-to-agreement (DTA) techniques were used to evaluate the discrepancy between measured and calculated dose values. Based on the criteria of DD less than 2% or DTA less than 2mm, 93.7% of 1,710 dose points for the 6 MV and 96.1% of 2,244 dose points for 15 MV passed. Dose points that failed were mostly for open fields, block tray fields, and physical wedges (15 and 30 degrees) fields; this is attributed to high electron contamination (EC) associated with these fields. The levels of discrepancies between measured and calculated dose values were greatly reduced after remodeling the EC in Pinnacle3 using Attix chamber measurements, an indication that the EC equation in Pinnacle3 may be adequate for modeling EC in the dose buildup region, and the commissioning of a TPS using cylindrical ionization chamber measurements may not provide accurate buildup region dose calculation. Attix chamber measurements were validated using GafChromic EBT2 film; the disagreement was less than 3% for 89.9% of dose values compared. © 2012 American Association of Physicists in Medicine.

  10. Neural correlates of blink suppression and the buildup of a natural bodily urge

    Science.gov (United States)

    Berman, Brian D.; Horovitz, Silvina G.; Morel, Brent; Hallett, Mark

    2011-01-01

    Neuroimaging studies have elucidated some of the underlying physiology of spontaneous and voluntary eye blinking; however, the neural networks involved in eye blink suppression remain poorly understood. Here we investigated blink suppression by analyzing fMRI data in a block design and event-related manner, and employed a novel hypothetical time-varying neural response model to detect brain activations associated with the buildup of urge. Blinks were found to activate visual cortices while our block design analysis revealed activations limited to the middle occipital gyri and deactivations in medial occipital, posterior cingulate and precuneus areas. Our model for urge, however, revealed a widespread network of activations including right greater than left insular cortex, right ventrolateral prefrontal cortex, middle cingulate cortex, and bilateral temporo-parietal cortices, primary and secondary face motor regions, and visual cortices. Subsequent inspection of BOLD time-series in an extensive ROI analysis showed that activity in the bilateral insular cortex, right ventrolateral prefrontal cortex, and bilateral STG and MTG showed strong correlations with our hypothetical model for urge suggesting these areas play a prominent role in the buildup of urge. The involvement of the insular cortex in particular, along with its function in interoceptive processing, help support a key role for this structure in the buildup of urge during blink suppression. The right ventrolateral prefrontal cortex findings in conjunction with its known involvement in inhibitory control suggest a role for this structure in maintaining volitional suppression of an increasing sense of urge. The consistency of our urge model findings with prior studies investigating the suppression of blinking and other bodily urges, thoughts, and behaviors suggests that a similar investigative approach may have utility in fMRI studies of disorders associated with abnormal urge suppression such as Tourette

  11. Build-up material requirements in clinical dosimetry during total body irradiation treatments.

    Science.gov (United States)

    Butson, Martin; Pope, Dane; Haque, Mamoon; Chen, Tom; Song, Guangli; Whitaker, May

    2016-01-01

    Total body irradiation (TBI) treatments are mainly used in a preparative regimen for hematopoietic stem cell (or bone marrow) transplantation. Our standard clinical regimen is a 12 Gy/6 fraction bi-daily technique using 6MV X-rays at a large extended source to surface distance (SSD). This work investigates and quantifies the dose build-up characteristics and thus the requirements for bolus used for in vivo dosimetry for TBI applications. Percentage dose build-up characteristics of photon beams have been investigated at large extended SSDs using ionization chambers and Gafchromic film. Open field measurements at different field sizes and with differing scatter conditions such as the introduction of standard Perspex scattering plates at different distances to the measurement point were made in an effort to determine the required bolus/build-up material required for accurate determination of applied dose. Percentage surface dose values measured for open fields at 300 cm SSD were found to range from 20% up to 65.5% for fields 5 cm × 5 cm to 40 cm × 40 cm, respectively. With the introduction of 1 cm Perspex scattering plates used in TBI treatments, the surface dose values increased up to 83-90% (93-97% at 1 mm depth), depending on the position of the Perspex scattering plate compared to the measurement point. Our work showed that at least 5 mm water equivalent bolus/scatter material should be placed over the EBT3 film for accurate dose assessment for TBI treatments. Results also show that a small but measurable decrease in measured dose occurred with 5 mm water equivalent thick bolus material of areas '3 cm(2). As such, we recommend that 3 cm × 3 cm × 5 mm bolus build-up is the smallest size that should be placed over EBT3 Gafchromic film when used for accurate in vivo dosimetry for TBI applications.

  12. The Build-up of Auditory Stream Segregation: A Different Perspective.

    Science.gov (United States)

    Deike, Susann; Heil, Peter; Böckmann-Barthel, Martin; Brechmann, André

    2012-01-01

    The build-up of auditory stream segregation refers to the notion that sequences of alternating A and B sounds initially tend to be heard as a single stream, but with time appear to split into separate streams. The central assumption in the analysis of this phenomenon is that streaming sequences are perceived as one stream at the beginning by default. In the present study, we test the validity of this assumption and document its impact on the apparent build-up phenomenon. Human listeners were presented with ABAB sequences, where A and B were harmonic tone complexes of seven different fundamental frequency separations (Δf) ranging from 2 to 14 semitones. Subjects had to indicate, as promptly as possible, their initial percept of the sequences, as either "one stream" or "two streams," and any changes thereof during the sequences. We found that subjects did not generally indicate a one-stream percept at the beginning of streaming sequences. Instead, the first perceptual decision depended on Δf, with the probability of a one-stream percept decreasing, and that of a two-stream percept increasing, with increasing Δf. Furthermore, subjects required some time to make and report a decision on their perceptual organization. Taking this time into account, the resulting time courses of two-stream probabilities differ markedly from those suggested by the conventional analysis. A build-up-like increase in two-stream probability was found only for the Δf of six semitones. At the other Δf conditions no or only minor increases in two-stream probability occurred. These results shed new light on the build-up of stream segregation and its possible neural correlates.

  13. The build-up of auditory stream segregation: a different perspective.

    Directory of Open Access Journals (Sweden)

    Susann eDeike

    2012-10-01

    Full Text Available The build-up of auditory stream segregation refers to the notion that sequences of alternating A and B sounds initially tend to be heard as a single stream, but with time appear to split into separate streams. The central assumption in the analysis of this phenomenon is that streaming sequences are perceived as one stream at the beginning by default. In the present study, we test the validity of this assumption and document its impact on the apparent build-up phenomenon. Human listeners were presented with ABAB sequences, where A and B were harmonic tone complexes of seven different fundamental frequency separations (∆f ranging from 2 to 14 semitones. Subjects had to indicate, as promptly as possible, their initial percept of the sequences, as either one stream or two streams, and any changes thereof during the sequences. We found that subjects did not generally indicate a one-stream percept at the beginning of streaming sequences. Instead, the first perceptual decision depended on ∆f, with the probability of a one-stream percept decreasing, and that of a two-stream percept increasing, with increasing ∆f. Furthermore, subjects required some time to make and report a decision on their perceptual organization. Taking this time into account, the resulting time courses of two-stream probabilities differ markedly from those suggested by the conventional analysis. A build-up-like increase in two-stream probability was found only for the ∆f of 6 semitones. At the other ∆f conditions no or only minor increases in two-stream probability occurred. These results shed new light on the build-up of stream segregation and its possible neural correlates.

  14. Placement of direct composite veneers utilizing a silicone buildup guide and intraoral mock-up.

    Science.gov (United States)

    Behle, C

    2000-04-01

    The indications for direct composite resins have recently been expanded to include predictable and convenient application in the aesthetic zone. The availability of composite materials with improved physical and optical characteristics facilitates the development of enhanced aesthetics while maintaining vital function. This article presents a simplified technique that combines function with aesthetics by utilizing an intraoral composite mock-up for initial communication and a lingual/incisal silicone stent of the mock-up to transfer the information to the definitive restorative buildup.

  15. Optimal Pile Arrangement for Minimizing Excess Pore Water Pressure Build-Up

    DEFF Research Database (Denmark)

    Barari, Amin; Saadati, Meysam; Ibsen, Lars Bo

    2013-01-01

    Numerical analysis of pile group in a liquefiable soil was considered to investigate the influence of pile spacing on excess pore pressure distribution and liquefaction potential. The analysis is conducted using a two-dimensional plain strain finite difference program considering a nonlinear...... constitutive model for sandy soil, strength and stiffness reduction, and pile-soil interaction. The Mohr-Coulomb constitutive model coupled with Byrne pore pressure build-up model have been employed in the analysis. Numerical analysis results show that pile groups have significant influence on the dynamic...

  16. Effect of radiation-induced charge accumulation on build-up cap on the signal current from an ionisation chamber.

    Science.gov (United States)

    Takata, N; Morishita, Y

    2011-04-01

    The signal current from a thimble ionisation chamber with a build-up cap made of an insulator decreases by about 0.41 % after being irradiated for 17 h at an air kerma rate of 41 Gy h(-1) by a collimated (60)Co gamma-ray beam in air. In contrast, the signal current remains constant when the thimble ionisation chamber is irradiated in a water phantom. During irradiation, positive charge is considered to accumulate near the outer surface of the build-up cap where electron equilibrium is not achieved. Secondary electrons travelling in the build-up cap and the chamber wall toward the ionisation volume are decelerated by the electric field generated by the positive charge. Consequently, the signal current decreases with increasing charge accumulation because some secondary electrons are prevented from entering the ionisation volume. In the water phantom, electron equilibrium is established in and around the ionisation chamber and charge does not accumulate. To confirm this hypothesis, the signal current was measured for an ionisation chamber in air with a build-up cap wrapped with Al foil and covered with PMMA tubes. Electron equilibrium was established over the build-up cap because the tubes were thicker than the secondary electron range. The signal current decreased with increasing positive voltage applied to the Al foil. It was estimated from the results that positive charges equivalent to a voltage of over 6 kV applied to the Al foil accumulated during irradiation. The signal current was also measured for an ionisation chamber with a metal build-up cap and for an ionisation chamber with a wall and build-up cap made of conductive plastic.

  17. Direct microscopic observation of hologram build-up in photorefractive crystals

    Science.gov (United States)

    Bányász, István; Mandula, Gábor

    2006-05-01

    A method, based on phase-contrast and interference microscopy, was developed for direct microscopic observation of temporal evolution of phase holograms in photorefractive crystals. Interference microscopy was adapted to the study of photorefractive holograms. First a hologram was recorded in the sample, and diffraction efficiency was monitored during hologram build-up using inactinic laser light. Thus kinetics of hologram build-up could be determined. The initial hologram was erased using white light. Then a series of write-erase cycles were performed with increasing exposure times up to an exposure corresponding to saturation of the grating. Holograms were observed by interference microscope after each exposure. The time elapsed between the exposure and the microscopic observation was negligible compared to the relaxation time of the hologram. The obtained temporal evolution of grating profile gives a deeper insight into the physical mechanism of hologram formation in photorefractive materials than diffraction efficiency measurements. Congruently grown samples of LiNbO 3: Fe, with Fe concentrations in melting of 10 -3 were studied by the above method. Sample thickness was set to 300 μm to allow correct microscopic observation. Plane-wave holograms were recorded in the samples using an Ar-ion laser at λ=514 nm of grating constants of 3.3 and 7.0 μm.

  18. Bacterial leakage through temporary fillings in core buildup composite material - an in vitro study.

    Science.gov (United States)

    Rechenberg, Dan-Krister; Schriber, Martina; Attin, Thomas

    2012-08-01

    To evaluate the ability of the provisional filling material Cavit-W alone or in combination with different restorative materials to prevent bacterial leakage through simulated access cavities in a resin buildup material. LuxaCore resin cylinders were subdivided into 4 experimental groups (n = 30), plus a positive (n = 5) and a negative (n = 30) control group. One bore hole was drilled through each cylinder, except those in the negative control group (G1). The holes were filled with Cavit-W (G2), Cavit-W and Ketac-Molar (glassionomer cement, G3), Cavit-W and LuxaCore bonded with LuxaBond (G4), Cavit-W and LuxaCore (G5), or left empty (G6). Specimens were mounted in a two-chamber leakage setup. The upper chamber was inoculated with E. faecalis. An enterococci-selective broth was used in the lower chamber. Leakage was assessed for 60 days and compared using Fisher's exact test (α Cavit-W alone or combined with a glass-ionomer cement did not prevent bacterial leakage through a resin buildup material for two months. In contrast, covering Cavit-W with a bonded resin material resulted in a bacteria-tight seal for two months.

  19. Galaxy Evolution at the Frontier: The Rate of Galaxy Buildup Between z~11 and z~8

    Science.gov (United States)

    Bradley, Larry

    2013-10-01

    Understanding the evolution of early galaxies and their contribution to reionization has been a longstanding goal of observational astronomy. Hubble's WFC3/IR camera has revolutionized our knowledge of 7 8 galaxies due to their faint luminosities {M*> -20.3} and low volume densities. In particular, blank-field studies suggest a very dramatic buildup in cosmic star-formation rate density {SFRD} in the 165 Myr between z 8-10. These results are in tension with lensed-field studies which suggest a smooth buildup of galaxies from z 10 to 4. To distinguish between these scenarios, deeper observations are required to increase z > 9 number statistics and to reduce the significant cosmic variance due to a single blank field with sufficient depth {UDF + surrounding regions}. The upcoming HST Frontier Fields {HSTFF} program will obtain ultra deep observations of both "blank" and cluster-lensed fields. The latter are more efficient for high-z searches but introduce magnification uncertainties which we have quantified and found to be subdominant to Poisson uncertainties. Based on the archival first-year HSTFF data, we will identify a large sample of 35-54 galaxies at 89 galaxy evolution and placing new constraints on reionization. Additionally, we will measure the rest-frame UV continuum slopes of z 6-8 galaxies to improve dust extinction estimates at high redshift, a key ingredient in SFRD measurements. We will also perform strong lensing analyses to produce some of the highest resolution cluster dark matter maps to date.

  20. Nonsurgical treatment of skeletal anterior open bite in adult patients: Posterior build-ups.

    Science.gov (United States)

    Vela-Hernández, Arturo; López-García, Rocio; García-Sanz, Verónica; Paredes-Gallardo, Vanessa; Lasagabaster-Latorre, Felicidad

    2017-01-01

    To (1) evaluate the efficacy of build-ups in the correction of anterior open bite in adults, (2) evaluate their efficacy in producing molar intrusion, (3) analyze skeletal and dental changes, and (4) assess the long-term stability. The sample consisted of 93 lateral cephalograms from 31 patients with skeletal and dental anterior open bite. The patients had received orthodontic treatment consisting of bonded resin blocks on the maxillary molars combined with Tip-Edge Plus bracket appliances. Cephalometric measurements were performed on radiographs taken before treatment (T1), after treatment (T2), and after a retention period (T3), which were analyzed and compared. Significant dental and skeletal changes were observed after treatment. Molar intrusion averaging 1 mm; 1.44 and 1.57 mm extrusion of mandibular and maxillary incisors, respectively; and a mean of 3.98 mm overbite increase were observed. The mandibular plane angle showed a mean closure of 1.19°, and there was a mean decrease in anterior facial height of 0.7 mm. A mild relapse tendency was observed, but long-term stability was acceptable. Build-ups are an effective treatment alternative for anterior open bite in adults. Outcomes remain significantly stable during the retention period.

  1. Influence of Experimental Parameters on Fatigue Crack Growth and Heat Build-Up in Rubber.

    Science.gov (United States)

    Stadlbauer, Franziska; Koch, Thomas; Archodoulaki, Vasiliki-Maria; Planitzer, Florian; Fidi, Wolfgang; Holzner, Armin

    2013-11-27

    Loading parameters (frequency, amplitude ratio and waveform) are varied to determine their influence on fatigue crack growth in rubber. Up to three different rubber blends are investigated: one actual engineering material and two model materials. Fatigue crack growth curves and strain distributions of pure shear and faint waist pure shear samples are compared for a model material. Fatigue behavior is studied for three different frequencies (1 Hz, 3 Hz and 5 Hz). Amplitude ratio appears to be another important influence factor concerning fatigue crack growth in rubber. The beneficial effect of positive amplitude ratios (tensional loading conditions) is shown for different materials. However, fatigue crack growth is considerably increased for negative amplitude ratios (tensional-compressional loading conditions). Furthermore, the influence of the waveform is determined for three different waveform shapes. One is sinusoidal, and two have a square shape, including dwell periods and sinusoidal slopes. Special focus lies on heat build-up, which is substantial, especially for large loads, high frequencies and/or highly filled rubber blends. Plateau temperatures are determined for various loading conditions and rubber blends. A very simple linear relationship with dissipated energy per time and unit area is obtained. Results gathered with dynamic mechanical analyses show, likewise, a linear trend, but the heat build-up is very small, due to different sample geometries.

  2. Build-up of toxic metals on the impervious surfaces of a commercial seaport.

    Science.gov (United States)

    Ziyath, Abdul M; Egodawatta, Prasanna; Goonetilleke, Ashantha

    2016-05-01

    In the context of increasing threats to the sensitive marine ecosystem by toxic metals, this study investigated the metal build-up on impervious surfaces specific to commercial seaports. The knowledge generated from this study will contribute to managing toxic metal pollution of the marine ecosystem. The study found that inter-modal operations and main access roadway had the highest loads followed by container storage and vehicle marshalling sites, while the quay line and short term storage areas had the lowest. Additionally, it was found that Cr, Al, Pb, Cu and Zn were predominantly attached to solids, while significant amount of Cu, Pb and Zn were found as nutrient complexes. As such, treatment options based on solids retention can be effective for some metal species, while ineffective for other species. Furthermore, Cu and Zn are more likely to become bioavailable in seawater due to their strong association with nutrients. Mathematical models to replicate the metal build-up process were also developed using experimental design approach and partial least squares regression. The models for Cr and Pb were found to be reliable, while those for Al, Zn and Cu were relatively less reliable, but could be employed for preliminary investigations. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. A STUDY INTO ICE BUILD-UP AND MELTING ON VERTICAL COOLED PIPES

    Directory of Open Access Journals (Sweden)

    Y. Zasiadko

    2016-08-01

    Full Text Available The use of cold accumulators based on the principle of ice build up on the cooled surfaces during off-peak periods and ice melting during on-peak periods is an effective method of electricity bills reduction. Within comparatively short periods of on-peak demand a noticeable amount of thermal energy related to ice melting is to be released, it becomes clear that not only sizing of ice accumulators based on balance calculations is actual, but also the determination of time periods of ice accumulation becomes critical. This work presents experimental unit for obtaining data on the ice build-up on the vertical cooled pipes and later on to continuously register data on the ice thickness diminishing at the regimes of ice melting when cooling of pipe stops. The data for ice build-up and melting for some regimes have been presented and analyzed. The data form the base for deriving semi-empirical correlations allowing to determine a time intervals necessary to generate of ice layers of a given thickness.

  4. Understanding the physical processes of pollutant build-up and wash-off on roof surfaces.

    Science.gov (United States)

    Egodawatta, Prasanna; Thomas, Evan; Goonetilleke, Ashantha

    2009-03-01

    Pollutants originating with roof runoff can have a significant impact on urban stormwater quality. This signifies the importance of understanding pollutant processes on roof surfaces. Additionally, knowledge of pollutant processes on roof surfaces is important as roofs are used as the primary catchment surface for domestic rainwater harvesting. In recent years, rainwater harvesting has become one of the primary sustainable water management techniques to counteract the growing demand for potable water. This paper presents the outcomes of an in-depth research study into particulate matter build-up and wash-off for roof surfaces. In this research, particulate matter was considered as the indicator pollutant where the processes related to other pollutants can be predicted based on the understanding generated for particulate matter. The study outcomes confirm that the build-up process on roof surfaces is comparatively similar to road surfaces. However, particle loads collected from roofs were significantly less compared to road surfaces and much finer in texture. Wash-off from roofs also showed significant similarities to wash-off from roads. A relatively high concentration of particulate matter was noted during the initial part of storm events. Furthermore, the amount of particulate matter remaining on the roof surfaces was significantly high for less intense rain events.

  5. An Empirical Model for Build-Up of Sodium and Calcium Ions in Small Scale Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    Subriyer Nasir

    2011-05-01

    Full Text Available A simple models for predicting build-up of solute on membrane surface were formulated in this paper. The experiments were conducted with secondary effluent, groundwater and simulated feed water in small-scale of RO with capacity of 2000 L/d. Feed water used in the experiments contained varying concentrations of sodium, calcium, combined sodium and calcium. In order to study the effect of sodium and calcium ions on membrane performance, experiments with ground water and secondary effluent wastewater were also performed. Build-up of salts on the membrane surface was calculated by measuring concentrations of sodium and calcium ions in feed water permeate and reject streams using Atomic Absorption Spectrophotometer (AAS. Multiple linear regression of natural logarithmic transformation was used to develop the model based on four main parameters that affect the build-up of solute in a small scale of RO namely applied pressure, permeate flux, membrane resistance, and feed concentration. Experimental data obtained in a small scale RO unit were used to develop the empirical model. The predicted values of theoretical build-up of sodium and calcium on membrane surface were found in agreement with experimental data. The deviation in the prediction of build-up of sodium and calcium were found to be 1.4 to 10.47 % and 1.12 to 4.46%, respectively.

  6. Differential aquaporin 4 expression during edema build-up and resolution phases of brain inflammation

    Science.gov (United States)

    2011-01-01

    Background Vasogenic edema dynamically accumulates in many brain disorders associated with brain inflammation, with the critical step of edema exacerbation feared in patient care. Water entrance through blood-brain barrier (BBB) opening is thought to have a role in edema formation. Nevertheless, the mechanisms of edema resolution remain poorly understood. Because the water channel aquaporin 4 (AQP4) provides an important route for vasogenic edema resolution, we studied the time course of AQP4 expression to better understand its potential effect in countering the exacerbation of vasogenic edema. Methods Focal inflammation was induced in the rat brain by a lysolecithin injection and was evaluated at 1, 3, 7, 14 and 20 days using a combination of in vivo MRI with apparent diffusion coefficient (ADC) measurements used as a marker of water content, and molecular and histological approaches for the quantification of AQP4 expression. Markers of active inflammation (macrophages, BBB permeability, and interleukin-1β) and markers of scarring (gliosis) were also quantified. Results This animal model of brain inflammation demonstrated two phases of edema development: an initial edema build-up phase during active inflammation that peaked after 3 days (ADC increase) was followed by an edema resolution phase that lasted from 7 to 20 days post injection (ADC decrease) and was accompanied by glial scar formation. A moderate upregulation in AQP4 was observed during the build-up phase, but a much stronger transcriptional and translational level of AQP4 expression was observed during the secondary edema resolution phase. Conclusions We conclude that a time lag in AQP4 expression occurs such that the more significant upregulation was achieved only after a delay period. This change in AQP4 expression appears to act as an important determinant in the exacerbation of edema, considering that AQP4 expression is insufficient to counter the water influx during the build-up phase, while the

  7. Humidity Build-Up in a Typical Electronic Enclosure Exposed to Cycling Conditions and Effect on Corrosion Reliability

    DEFF Research Database (Denmark)

    Conseil, Helene; Gudla, Visweswara Chakravarthy; Jellesen, Morten Stendahl

    2016-01-01

    The design of electronic device enclosures plays a major role in determining the humidity build-up inside the device as a response to the varying external humidity. Therefore, the corrosion reliability of electronic devices has direct connection to the enclosure design. This paper describes...... the internal humidity build-up in a typical enclosure prescribed for electronic applications as a function of external humidity conditions and enclosure-related parameters. Investigated parameters include external temperature and humidity conditions, the temperature and time of the internal heating cycle......, thermal mass, and port/opening size. The effect of the internal humidity build-up on corrosion reliability has been evaluated by measuring the leakage current (LC) on interdigitated test comb patterns, which are precontaminated with sodium chloride and placed inside the enclosure. The results showed...

  8. Linear attenuation coefficient and buildup factor of MCP-96 alloy for dose accuracy, beam collimation, and radiation protection.

    Science.gov (United States)

    Hopkins, Deidre N; Maqbool, Muhammad; Islam, Mohammed S

    2012-07-01

    The linear attenuation coefficients and buildup factor of MCP-96 alloy were determined for (60)Co, (54)Mn, and (137)Cs gamma emitters and a NaI detector. The thickness of the MCP-96 attenuator was varied from 1 to 4 cm. A collimated beam of gamma rays was allowed to pass through various thicknesses of the MCP-96 alloy. The attenuated beam was detected by a NaI detector, and data were recorded by a multichannel analyzer. The run was repeated without the collimator for broad-beam geometry. For each run, the attenuated beam intensity was normalized by the intensity of the unattenuated incident beam obtained by removing the attenuators. Linear attenuation coefficients were determined by plotting of the intensity of the collimated beam against the attenuator thickness. For every thickness of the alloy, the ratio of the attenuated to the unattenuated beam was found to be higher in broad-beam geometry as compared to the same ratio in narrow-beam geometry. We used the difference in these ratios in broad and narrow-beam geometries to calculate the buildup factor. The buildup factor was found to increase with beam energy and attenuator thickness. Variation in the source-to-detector distance gave a lower value of the buildup factor for a small and a large distance and a higher value for an intermediate distance. The buildup factor was found to be greater than 1 in all cases. We conclude that the buildup factor must be calculated and incorporated for dose correction and precision when the MCP-96 alloy is used for tissue compensation or radiation shielding and protection purposes.

  9. Triplet fraction buildup effect of the DNA-YOYO complex studied with fluorescence correlation spectroscopy.

    Science.gov (United States)

    Shimizu, Masafumi; Sasaki, Satoshi; Kinjo, Masataka

    2007-07-01

    DNA fragments of various lengths and YOYO-1 iodide (YOYO) were mixed at various ratios, and fluorescence was measured using fluorescence correlation spectroscopy. The number of substantially emitting YOYO molecules binding to the DNA and the binding intervals between the YOYO molecules were estimated for DNA-YOYO complexes of various lengths. In the present study, we found an interesting phenomenon: triplet buildup. Because fluorophores that fall into the triplet state do not emit fluorescence, a part of the dark period can be recovered by emitting photons from other excited YOYO molecules in the same DNA strings in the confocal elements. The remaining dark period can be considered to be the total miss-emission rate. Estimates of the total miss-emission rate are important for calculation of the length and amount of DNA.

  10. Electron cloud buildup and related instability in the CERN Proton Synchrotron

    CERN Document Server

    Cappi, R; Métral, Elias; Métral, G; Rumolo, Giovanni; Zimmermann, Frank

    2002-01-01

    The beam-induced electron cloud buildup is one of the major concerns for the SPS and the design of the future LHC. During the 2000 run, this effect has also been observed in the PS with the nominal LHC- type beam. The electron cloud induces a baseline distortion in electrostatic pickup signals, both during the last turns in the PS, when the full bunch length is reduced to less than 4 ns, and in the transfer line between the PS and the SPS rings. In the year 2001, modifications in the rf hardware allowed us to study the properties of the beam instability related with the electron cloud phenomenon for a total bunch length of about 10 ns. The complete set of experimental observations carried out in the PS machine is presented and discussed in detail. (20 refs).

  11. Deciphering Molecular Mechanisms of Interface Buildup and Stability in Porous Si/Eumelanin Hybrids

    Science.gov (United States)

    Pinna, Elisa; Melis, Claudio; Antidormi, Aleandro; Cardia, Roberto; Sechi, Elisa; Cappellini, Giancarlo; Colombo, Luciano

    2017-01-01

    Porous Si/eumelanin hybrids are a novel class of organic–inorganic hybrid materials that hold considerable promise for photovoltaic applications. Current progress toward device setup is, however, hindered by photocurrent stability issues, which require a detailed understanding of the mechanisms underlying the buildup and consolidation of the eumelanin–silicon interface. Herein we report an integrated experimental and computational study aimed at probing interface stability via surface modification and eumelanin manipulation, and at modeling the organic–inorganic interface via formation of a 5,6-dihydroxyindole (DHI) tetramer and its adhesion to silicon. The results indicated that mild silicon oxidation increases photocurrent stability via enhancement of the DHI–surface interaction, and that higher oxidation states in DHI oligomers create more favorable conditions for the efficient adhesion of growing eumelanin. PMID:28753933

  12. Model study of the pressure build-up during subcutaneous injection.

    Directory of Open Access Journals (Sweden)

    Maria Thomsen

    Full Text Available In this study we estimate the subcutaneous tissue counter pressure during drug infusion from a series of injections of insulin in type 2 diabetic patients using a non-invasive method. We construct a model for the pressure evolution in subcutaneous tissue based on mass continuity and the flow laws of a porous medium. For equivalent injection forces we measure the change in the infusion rate between injections in air at atmospheric pressure and in tissue. From a best fit with our model, we then determine the flow permeability as well as the bulk modulus of the tissue, estimated to be of the order 10-11-10-10 m2 and 105 Pa, respectively. The permeability is in good agreement with reported values for adipose porcine tissue. We suggest our model as a general way to estimate the pressure build-up in tissue during subcutaneous injection.

  13. Model Study of the Pressure Build-Up during Subcutaneous Injection

    DEFF Research Database (Denmark)

    Thomsen, Maria; Hernandez Garcia, Anier; Mathiesen, Joachim

    2014-01-01

    In this study we estimate the subcutaneous tissue counter pressure during drug infusion from a series of injections of insulin in type 2 diabetic patients using a non-invasive method. We construct a model for the pressure evolution in subcutaneous tissue based on mass continuity and the flow laws...... of a porous medium. For equivalent injection forces we measure the change in the infusion rate between injections in air at atmospheric pressure and in tissue. From a best fit with our model, we then determine the flow permeability as well as the bulk modulus of the tissue, estimated to be of the order 10......-11-10-10 m2 and 105 Pa, respectively. The permeability is in good agreement with reported values for adipose porcine tissue. We suggest our model as a general way to estimate the pressure build-up in tissue during subcutaneous injection....

  14. Space charge build-up in XLPE-cable with temperature gradient

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens; Hjerrild, Jesper

    2000-01-01

    and temperatures were applied in the 20 - 80°C range with gradients across the insulation of up to 15°C. In this paper, the observed charge phenomena in the bulk and at the interfaces are related to the external conditions, in particular to the temperature gradient. The measured space charge distributions......Space charge build-up in standard XLPE insulated AC cables has been studied under varying temperature and field conditions. The cables were triple-extruded with the inner semicon on a solid aluminum conductor, 5.5mm XLPE-insulation and an outer semicon. The cables were stressed up to 15kV/mm DC...

  15. Comparative Evaluation of Shear Bond Strength of Luting Cements to Different Core Buildup Materials in Lactic Acid Buffer Solution.

    Science.gov (United States)

    Patil, Siddharam M; Kamble, Vikas B; Desai, Raviraj G; Arabbi, Kashinath C; Prakash, Ved

    2015-08-01

    The core buildup material is used to restore badly broken down tooth to provide better retention for fixed restorations. The shear bond strength of a luting agent to core buildup is one of the crucial factors in the success of the cast restoration. The aim of this invitro study was to evaluate and compare the shear bond strength of luting cements with different core buildup materials in lactic acid buffer solution. Two luting cements {Traditional Glass Ionomer luting cement (GIC) and Resin Modified Glass Ionomer luting cement (RMGIC)} and five core buildup materials {Silver Amalgam, Glass ionomer (GI), Glass Ionomer Silver Reinforced (GI Silver reinforced), Composite Resin and Resin Modified Glass Ionomer(RMGIC)} were selected for this study. Total 100 specimens were prepared with 20 specimens for each core buildup material using a stainless steel split metal die. Out of these 20 specimens, 10 specimens were bonded with each luting cement. All the bonded specimens were stored at 37(0)c in a 0.01M lactic acid buffer solution at a pH of 4 for 7days. Shear bond strength was determined using a Universal Testing Machine at a cross head speed of 0.5mm/min. The peak load at fracture was recorded and shear bond strength was calculated. The data was statistically analysed using Two-way ANOVA followed by HOLM-SIDAK method for pair wise comparison at significance level of pstrength of the luting cements (pcore materials (pstrength values than Traditional GIC luting cement for all the core buildup materials. RMGIC core material showed higher bond strength values followed by Composite resin, GI silver reinforced, GI and silver amalgam core materials for both the luting agents. Shear bond strength of RMGIC luting cement was significantly higher than traditional GIC luting cement for all core buildup materials except, for silver amalgam core buildup material. RMGIC core material showed highest shear bond strength values followed by Composite resin, GI Silver Reinforced, GI and

  16. Protein structure determination via an efficient geometric build-up algorithm

    Science.gov (United States)

    2010-01-01

    Background A protein structure can be determined by solving a so-called distance geometry problem whenever a set of inter-atomic distances is available and sufficient. However, the problem is intractable in general and has proved to be a NP hard problem. An updated geometric build-up algorithm (UGB) has been developed recently that controls numerical errors and is efficient in protein structure determination for cases where only sparse exact distance data is available. In this paper, the UGB method has been improved and revised with aims at solving distance geometry problems more efficiently and effectively. Methods An efficient algorithm (called the revised updated geometric build-up algorithm (RUGB)) to build up a protein structure from atomic distance data is presented and provides an effective way of determining a protein structure with sparse exact distance data. In the algorithm, the condition to determine an unpositioned atom iteratively is relaxed (when compared with the UGB algorithm) and data structure techniques are used to make the algorithm more efficient and effective. The algorithm is tested on a set of proteins selected randomly from the Protein Structure Database-PDB. Results We test a set of proteins selected randomly from the Protein Structure Database-PDB. We show that the numerical errors produced by the new RUGB algorithm are smaller when compared with the errors of the UGB algorithm and that the novel RUGB algorithm has a significantly smaller runtime than the UGB algorithm. Conclusions The RUGB algorithm relaxes the condition for updating and incorporates the data structure for accessing neighbours of an atom. The revisions result in an improvement over the UGB algorithm in two important areas: a reduction on the overall runtime and decrease of the numeric error. PMID:20487514

  17. Protein structure determination via an efficient geometric build-up algorithm.

    Science.gov (United States)

    Davis, Robert T; Ernst, Claus; Wu, Di

    2010-05-17

    A protein structure can be determined by solving a so-called distance geometry problem whenever a set of inter-atomic distances is available and sufficient. However, the problem is intractable in general and has proved to be a NP hard problem. An updated geometric build-up algorithm (UGB) has been developed recently that controls numerical errors and is efficient in protein structure determination for cases where only sparse exact distance data is available. In this paper, the UGB method has been improved and revised with aims at solving distance geometry problems more efficiently and effectively. An efficient algorithm (called the revised updated geometric build-up algorithm (RUGB)) to build up a protein structure from atomic distance data is presented and provides an effective way of determining a protein structure with sparse exact distance data. In the algorithm, the condition to determine an unpositioned atom iteratively is relaxed (when compared with the UGB algorithm) and data structure techniques are used to make the algorithm more efficient and effective. The algorithm is tested on a set of proteins selected randomly from the Protein Structure Database-PDB. We test a set of proteins selected randomly from the Protein Structure Database-PDB. We show that the numerical errors produced by the new RUGB algorithm are smaller when compared with the errors of the UGB algorithm and that the novel RUGB algorithm has a significantly smaller runtime than the UGB algorithm. The RUGB algorithm relaxes the condition for updating and incorporates the data structure for accessing neighbours of an atom. The revisions result in an improvement over the UGB algorithm in two important areas: a reduction on the overall runtime and decrease of the numeric error.

  18. Influence of no-ferrule and no-post buildup design on the fatigue resistance of endodontically treated molars restored with resin nanoceramic CAD/CAM crowns.

    Science.gov (United States)

    Magne, P; Carvalho, A O; Bruzi, G; Anderson, R E; Maia, H P; Giannini, M

    2014-01-01

    To evaluate the influence of adhesive core buildup designs-4-mm buildup, 2-mm buildup, and no buildup (endocrown)-on the fatigue resistance and failure mode of endodontically treated molar teeth restored with resin nanoceramic (RNC) CAD/CAM complete crowns placed with self-adhesive resin cement. Forty-five extracted molars were decoronated at the level of the cementoenamel junction, and the roots were endodontically treated. Specimens received different Filtek Z100 adhesive core buildups (4-mm buildup, 2-mm buildup, and no buildup, endocrown preparation) and were restored with Cerec 3 CAD/CAM RNC crowns (Lava Ultimate). Restorations (n=15) and prepared teeth were treated with airborne-particle abrasion, followed by cementation with RelyX Unicem 2 Automix. Specimens were then subjected to cyclic isometric loading at 10 Hz, beginning with a load of 200 N (for 5000 cycles), followed by stages of 400, 600, 800, 1000, 1200, and 1400 N at a maximum of 30,000 cycles each. Specimens were loaded until failure or to a maximum of 185,000 cycles (10-mm-diameter composite resin sphere antagonist). The failure mode was assessed: "catastrophic" (tooth/root fracture that would require tooth extraction), "possibly reparable" (cohesive/adhesive failure with fragment and minor damage, chip or crack, of underlying tooth structure), or "reparable" fracture (cohesive or cohesive/adhesive fracture of restoration only). Groups were compared using the life table survival analysis. Intact specimens were loaded to failure and compared with one-way analysis of variance. All specimens survived the fatigue test until the 800 N-step. The survival rates for 4-mm, 2-mm, and no buildup (endocrown) were 53%, 87%, and 87%, respectively, and were not statistically different even though crowns with 2-mm buildups only started to fail at 1200 N. Minor cohesive chips were detected in many samples despite having survived all 185,000 cycles. Postfatigue load-to-failure ranged from 2969 N with 4-mm buildup

  19. The effects of preceding lead-alone and lag-alone click trains on the buildup of echo suppression

    Science.gov (United States)

    Bishop, Christopher W.; Yadav, Deepak; London, Sam; Miller, Lee M.

    2014-01-01

    Spatial perception in echoic environments is influenced by recent acoustic history. For instance, echo suppression becomes more effective or “builds up” with repeated exposure to echoes having a consistent acoustic relationship to a temporally leading sound. Four experiments were conducted to investigate how buildup is affected by prior exposure to unpaired lead-alone or lag-alone click trains. Unpaired trains preceded lead-lag click trains designed to evoke and assay buildup. Listeners reported how many sounds they heard from the echo hemifield during the lead-lag trains. Stimuli were presented in free field (experiments 1 and 4) or dichotically through earphones (experiments 2 and 3). In experiment 1, listeners reported more echoes following a lead-alone train compared to a period of silence. In contrast, listeners reported fewer echoes following a lag-alone train; similar results were observed with earphones. Interestingly, the effects of lag-alone click trains on buildup were qualitatively different when compared to a no-conditioner trial type in experiment 4. Finally, experiment 3 demonstrated that the effects of preceding click trains on buildup cannot be explained by a change in counting strategy or perceived click salience. Together, these findings demonstrate that echo suppression is affected by prior exposure to unpaired stimuli. PMID:25096114

  20. Insect Venom Immunotherapy: Analysis of the Safety and Tolerance of 3 Buildup Protocols Frequently Used in Spain.

    Science.gov (United States)

    Gutiérrez Fernández, D; Moreno-Ancillo, A; Fernández Meléndez, S; Domínguez-Noche, C; Gálvez Ruiz, P; Alfaya Arias, T; Carballada González, F; Alonso Llamazares, A; Marques Amat, L; Vega Castro, A; Antolín Amérigo, D; Cruz Granados, S; Ruiz León, B; Sánchez Morillas, L; Fernández Sánchez, J; Soriano Gomis, V; Borja Segade, J; Dalmau Duch, G; Guspi Bori, R; Miranda Páez, A

    2016-01-01

    Hymenoptera venom immunotherapy (VIT) is an effective treatment but not one devoid of risk, as both local and systemic adverse reactions may occur, especially in the initial phases. We compared the tolerance to 3 VIT buildup protocols and analyzed risk factors associated with adverse reactions during this phase. We enrolled 165 patients divided into 3 groups based on the buildup protocol used (3, 4, and 9 weeks). The severity of systemic reactions was evaluated according to the World Allergy Organization model. Results were analyzed using exploratory descriptive statistics, and variables were compared using analysis of variance. Adverse reactions were recorded in 53 patients (32%) (43 local and 10 systemic). Local reactions were immediate in 27 patients (63%) and delayed in 16 (37%). The severity of the local reaction was slight/moderate in 15 patients and severe in 13. Systemic reactions were grade 1-2. No significant association was found between the treatment modality and the onset of local or systemic adverse reactions or the type of local reaction. We only found a statistically significant association between severity of the local reaction and female gender. As for the risk factors associated with systemic reactions during the buildup phase, we found no significant differences in values depending on the protocol used or the insect responsible. The buildup protocols compared proved to be safe and did not differ significantly from one another. In the population studied, patients undergoing the 9-week schedule presented no systemic reactions. Therefore, this protocol can be considered the safest approach.

  1. The build-up dynamic and chemical fractionation of Cu, Zn and Cd in road-deposited sediment.

    Science.gov (United States)

    Zhang, Jin; Hua, Pei; Krebs, Peter

    2015-11-01

    This study investigates the build-up dynamics of heavy metals on impervious urban surfaces with different antecedent dry-weather periods (ADPs) and land-use types. Solid-phase concentration (mg/kg), surface load (mg/m(2)), and chemical fractionation of Zn, Cu and Cd in bulk- and size-fractionated road-deposited sediment were determined. The inherent correlations among particle size distribution, ADP, land use, and chemical fractionation were analysed by hierarchical cluster analysis. Results show a clear build-up phenomenon of Cu and Zn at a city commercial centre and a highway area. Cd had complex build-up patterns. With regard to chemical fractionation, Zn and Cd could pose higher risks than Cu to aquatic biota after a longer ADP. Special attention should be paid to the significant risk in a rural area because of the high proportion of exchangeable chemical fractionation in terms of the unstable Cd component. Hierarchical cluster analysis indicates that ADP had a strong influence on build-up processes of sediments and associated metals. The metal contents were very dependent on the particle size distribution. However, the chemical fractionation of metals was dependent to a lesser extent on the land-use type. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Orientation-dependent proton double-quantum NMR build-up function for soft materials with anisotropic mobility.

    Science.gov (United States)

    Naumova, Anna; Tschierske, Carsten; Saalwächter, Kay

    In recent years, the analysis of proton double-quantum NMR build-up curves has become an important tool to quantify anisotropic mobility in different kinds of soft materials such as polymer networks or liquid crystals. In the former case, such data provides a measure of orientation-dependent residual (time-averaged) dipolar couplings arising from anisotropic segmental motions, informing about the length and the state of local stretching of the network chains. Previous studies of macroscopically ordered, i.e. stretched, networks were subject to the limitation that a detailed build-up curve analysis on the basis of a universal "Abragam-like" (A-l) build-up function valid for a proton multi-spin system was only possible for an isotropic orientation-averaged response. This situation is here remedied by introducing a generic orientation-dependent build-up function for an anisotropically mobile protonated molecular segment. We discuss an application to the modeling of data for a stretched network measured at different orientations with respect to the magnetic field, and present a validation by fitting data of different liquid-crystal molecules oriented in the magnetic field. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Inherent errors in pollutant build-up estimation in considering urban land use as a lumped parameter.

    Science.gov (United States)

    Liu, An; Goonetilleke, Ashantha; Egodawatta, Prasanna

    2012-01-01

    Stormwater quality modeling results are subject to uncertainty. The variability of input parameters is an important source of overall model error. An in-depth understanding of the variability associated with input parameters can provide knowledge on the uncertainty associated with these parameters and can assist in uncertainty analysis of stormwater quality models and decision making based on modeling outcomes. This paper discusses the outcomes of a research study undertaken to analyze the variability related to pollutant build-up parameters in stormwater quality modeling. The study was based on the analysis of pollutant build-up samples collected from 12 road surfaces in residential, commercial, and industrial land uses. It was found that build-up characteristics vary appreciably even within the same land use. Therefore, using land use as a lumped parameter would contribute significant uncertainties in stormwater quality modeling. Additionally, it was found that the variability in pollutant build-up can be significant depending on the pollutant type. This underlines the importance of taking into account specific land use characteristics and targeted pollutant species when undertaking uncertainty analysis of stormwater quality models or in interpreting the modeling outcomes. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  4. 76 FR 7238 - Pipeline Safety: Dangers of Abnormal Snow and Ice Build-Up on Gas Distribution Systems

    Science.gov (United States)

    2011-02-09

    ... steps to prevent damage to pipeline facilities from accumulated snow or ice. Past events on natural gas.... Subject: Dangers of Abnormal Snow and Ice Build-up on Gas Distribution Systems. Purpose: To remind owners... Pipeline and Hazardous Materials Safety Administration Pipeline Safety: Dangers of Abnormal Snow and Ice...

  5. Variation of energy absorption buildup factors with incident photon energy and penetration depth for some commonly used solvents

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Parjit S. [Department of Physics, Punjabi University, Patiala 147 002 (India)], E-mail: dr_parjit@hotmail.com; Singh, Tejbir [Department of Physics, Lovely Professional University, Phagwara 144 402 (India); Kaur, Paramjeet [IAS and Allied Services Training Centre, Punjabi University, Patiala 147 002 (India)

    2008-06-15

    G.P. fitting method has been used to compute energy absorption buildup factor of some commonly used solvents such as acetonitrile (C{sub 4}H{sub 3}N), butanol (C{sub 4}H{sub 9}OH), chlorobenzene (C{sub 6}H{sub 5}Cl), diethyl ether (C{sub 4}H{sub 10}O), ethanol (C{sub 2}H{sub 5}OH), methanol (CH{sub 3}OH), propanol (C{sub 3}H{sub 7}OH) and water (H{sub 2}O) for the wide energy range (0.015-15.0 MeV) up to the penetration depth of 10 mean free path. The variation of energy absorption buildup factor with chemical composition as well as incident photon energy for the selected solvents has been studied. It has been observed that the maximum value of energy absorption buildup factors shifts to the slightly higher incident photon energy with the increase in equivalent atomic number of the solvent and the solvent with least equivalent atomic number possesses the maximum value of energy absorption buildup factor.

  6. Differences in wedge factor determination in air using a PMMA mini-phantom or a brass build-up cap.

    Science.gov (United States)

    Heukelom, S; Lanson, J H; Mijnheer, B J

    1997-12-01

    The head scatter dose contribution to the output of a treatment machine has been determined for an open and wedged 60Co gamma-ray beam and for open and wedged x-ray beams of 4, 8, and 16 MV. From those data wedge factor values "in air" have been deduced, expressed as the ratio of the dose to water, measured in air, for the situation with and without wedge, for the same number of monitor units (or treatment time for 60Co). The measurements have been performed using a polymethyl-metacrylate (PMMA) and a graphite-walled ionization chamber inserted in a brass build-up cap and in a PMMA mini-phantom, respectively. Absolute wedge factor values deduced with both detector systems and based on the ratio of ionization chamber readings, differ for the investigated photon beams, up to 3.5% for the 4 MV x-ray beam. The deviations results from the difference in composition between the detector materials and water and can be taken into account by conversion of the ionization chamber readings for both the open and wedged photon beams to the absorbed dose to water. For the brass build-up cap detector system the ratio of the conversion factors for the wedged and open beam changes the ratio of the ionization chamber readings up to about 3.6% for the 4 MV x-ray beam. For the mini-phantom the conversion factors for the wedged and open beam are almost equal for all photon beams. Consequently, for that system wedge factors based on ionization chamber readings or dose values are the same. With respect to the wedge factor variation with field size a somewhat larger increase has been determined for the 60Co and 4 MV photon beam using the brass build-up cap: about 1% for field sizes varying between 5 cm x 5 cm and 15 cm x 15 cm. This effect has to be related to an apparent more pronounced variation of the head scatter dose contribution with field size for the wedged photon beams if the brass build-up cap detection system is used. It can be concluded that determination of wedge factors "in

  7. Cenozoic topographic build-up of the Iranien plateau: first constraints from low-temperature thermochronology

    Science.gov (United States)

    François, Thomas; Agard, Philippe; Meyer, Bertrand; Zarrinkoub, Mohammad; Chung, Sun-Lin; Bernet, Matthias; Burov, Evgueni

    2013-04-01

    The Iranian plateau is a smooth topographic high at the rear of the Zagros mountains, with average elevation of c. 1.5 km. Its formation is thought to result from the collision between the Arabian and Eurasian plates since ~35 Myrs, following a long-standing subduction, and represents an interesting analogue to the so far better documented Tibetan plateau. Yet, while the Zagros orogeny was reappraised by numerous authors over the past few years, the topographic build-up of both the Zagros and the Iranian plateau remains ill-constrained. We herein present (U-Th)/He and fission track (FT) thermochronology results to reconstruct the Cenozoic tectonic evolution of the Iranien plateau and quantify the age and amount of vertical movements. Apatite and zircon single grain cooling age data were collected on plutonic rocks (for which crystallization ages were already available: Chiu et al., 2010) from the internal domains of Sanandaj-Sirjan Zone (SSZ), Urumieh-Doktar magmatic arc (UDMA), Central Iran and, for comparison, Kopet Dagh. We stress that an important milestone for topographic build-up is the presence of the marine Qom formation (coeval with the external Asmari formation) in the UDMA and part of the SSZ, indicating that the plateau was at or near sea level at 20 Ma. Temperature time paths inferred from low temperature thermochronology suggest a spatial and temporal separation of exhumation processes. The results show that the SSZ was exhumed very early in the collision process (essentially before 20 Ma), with a likely acceleration around the Oligocene (i.e., at the onset of continental collision) from 0.05 to 0.3 mm/yr. Post-collision cooling along the UDMA is marked by an average, constant exhumation rate of 0.3-0.4 mm/yr, which suggests that no significant increase or decrease of erosion occurred since continental collision. In Central Iran, the overlap (within error) of ZrFT, AFT and AHe ages from gneissic samples points to their rapid cooling during the upper

  8. The Convective Cloud Population during the Buildup of the Madden-Julian Oscillation

    Science.gov (United States)

    Houze, R.; Brodzik, S.; Yuan, J.

    2011-12-01

    A-Train and TRMM satellite data have been analyzed over the Indian Ocean, in the region where Madden Julian Oscillation (MJO) originates. The convective cloud population over this region evolves from suppressed conditions with environmental moisture confined to low levels and mostly shallow clouds to a deep moist layer containing deep convective towers and mesoscale convective systems (MCSs). Once the deep clouds become dominant the MJO disturbance propagates out of the region to the east, and the buildup cycle repeats. Understanding this buildup of the cloud population from suppressed to active over the Indian Ocean is thought to be a key to better forecasting of the MJO and all of its associated effects on weather and climate. In this study we use the TRMM satellite's Precipitation Radar (PR) data to identify isolated shallow convective rain elements, deep convective rain elements, and broad stratiform radar echoes over the Indian Ocean for a multiyear dataset. The PR data are stratified according to phases 1-8 of the MJO, as defined by Wheeler and Hendon (2004). Over the Indian Ocean phases 2-3 are active with deep convection and 5-6 are suppressed. The change in conditions from phases 5-6 to phases 1-2 is the buildup period of the MJO disturbance over the Indian Ocean. The shallow isolated rain cells are ubiquitously present in all phases, with a very slight increase in number in phases 5-6. The deep convective elements exhibit a mild variation with maximum occurrence in phases 2-3. The most pronounced variation over the Indian Ocean is in the occurrence of broad stratiform regions, which are most frequent in phases 2-3 and nearly absent in phases 5-7. These variations in the TRMM PR data are consistent with observations of MCSs with the A-Train Aqua satellite. Using the method developed by Yuan and Houze (2010) we identify MCSs objectively with a combination of algorithms applied to the MODIS brightness temperature field and AMSR-E rain data, both from the A

  9. Impacts of traffic and rainfall characteristics on heavy metals build-up and wash-off from urban roads.

    Science.gov (United States)

    Mahbub, Parvez; Ayoko, Godwin A; Goonetilleke, Ashantha; Egodawatta, Prasanna; Kokot, Serge

    2010-12-01

    An investigation into the effects of changes in urban traffic characteristics due to rapid urbanisation and the predicted changes in rainfall characteristics due to climate change on the build-up and wash-off of heavy metals was carried out in Gold Coast, Australia. The study sites encompassed three different urban land uses. Nine heavy metals commonly associated with traffic emissions were selected. The results were interpreted using multivariate data analysis and decision making tools, such as principal component analysis (PCA), fuzzy clustering (FC), PROMETHEE, and GAIA. Initial analyses established high, low, and moderate traffic scenarios as well as low, low to moderate, moderate, high, and extreme rainfall scenarios for build-up and wash-off investigations. GAIA analyses established that moderate to high traffic scenarios could affect the build-up, while moderate to high rainfall scenarios could affect the wash-off of heavy metals under changed conditions. However, in wash-off, metal concentrations in 1-75 μm fraction were found to be independent of the changes to rainfall characteristics. In build-up, high traffic activities in commercial and industrial areas influenced the accumulation of heavy metal concentrations in particulate size range from 75 - >300 μm, whereas metal concentrations in finer size range of 300 μm can be targeted for removal of Ni, Cu, Pb, Cd, Cr, and Zn from build-up, while organic matter from 300 μm can be targeted for removal of Cd, Cr, Pb, and Ni from wash-off. Cu and Zn need to be removed as free ions from most fractions in wash-off.

  10. Foreign Body Reaction to Biomaterials: On Mechanisms for Buildup and Breakdown of Osseointegration.

    Science.gov (United States)

    Trindade, Ricardo; Albrektsson, Tomas; Tengvall, Pentti; Wennerberg, Ann

    2016-02-01

    The last few decades have seen a progressive shift in paradigm, replacing the notion of body implants as inert biomaterials for that of immune-modulating interactions with the host. This text represents an attempt at understanding the current knowledge on the healing mechanisms controlling implant-host interactions, thus interpreting osseointegration and the peri-implant bone loss phenomena also from an immunological point of view. A narrative review approach was taken in the development of this article. Osseointegration, actually representing a foreign body reaction (FBR) to biomaterials, is an immune-modulated, multifactorial, and complex healing process where a number of cells and mediators are involved. The buildup of osseointegration seems to be an immunologically and inflammatory-driven process, with the ultimate end to shield off the foreign material placed in the body, triggered by surface protein adsorption, complement activation, and buildup of a fibrin matrix, followed by recruitment of granulocytes, mesenchymal stem cells, and monocytes/macrophages, with the latter largely controlling the longer term response, further fusing into foreign body giant cells (FBGC), while bone cells make and remodel hydroxyl apatite. The above sequence results in the FBR that we call osseointegration and use for clinical purposes. However, the long-term clinical function is dependent on a foreign body equilibrium, that if disturbed may lead to impaired clinical function of the implant, through a breakdown process where macrophages are again activated and may further fuse into FBGCs, now seen in much greater numbers, resulting in the start of bone resorption - due to cells such as osteoclasts with different origins and possibly even macrophages degrading more bone than what is formed via osteoblastic activity - and rupture of mucosal seals, through complex mechanisms in need of further understanding. Infection may follow as a secondary event, further complicating the

  11. Uji ketahanan galur padi terhadap wereng coklat biotipe 3 melalui population build-up

    Directory of Open Access Journals (Sweden)

    Baehaki Suherlan Effendi

    2015-09-01

    Full Text Available Screening of rice lines resistance to brown planthopper (BPH through mass screening, filtering line resistance and the population build-up are essential for the release of resistant rice varieties. In addition, the stages of the endurance are important in determining the stability of resistance, as well as the type of resistant. The research was carried out in the screen house at Indonesian Center for Rice Research in 2007. The BPH used in the research was the off spring of BPH biotype 3 that had been rearing on IR42 (bph2 variety since 1994. The result of this research showed that 22.2% of 18 lines/varieties were moderately resistant to BPH biotype 3ft namely BP4130-1f-13-3-2*B, BP4188-7f-1-2-2*B, BP2870-4e- Kn-22-2-1-5*B, and Pulut Lewok. On the population build-up test, the above lines/varieties were moderately resistant to BPH biotype 3pb. The low FPLI values were found in BP4130-1f-13-3-2*B and Pulut Lewok. The highest tolerance index was found on BP4130-1f- 13-3-2*B and Pulut Lewok followed by BP2870-4e-Kn-22-2-1-5*B and BP4188-7f-1-2-2*B. Pulut Lewok has the highest antibiosis index and is not significantly different to BP4130-1f-13-3-2*B, while BP4188-7f-1-2-2*B was lowest. Although Pulut Lewok has antibiosis defense mechanism, it is not tolerant to BPH biotype 3. The BP4130-1f-13-3-2*B line have both antibiosis and tolerant to BPH biotype 3. BP4188-7f-1-2-2*B line has tolerance character, but does not have character of antibiosis to BPH biotype 3.

  12. Calculation of gamma-ray buildup factors up to depths of 100 mfp by the method of invariant embedding. (2) Improved treatment of bremsstrahlung

    CERN Document Server

    Shimizu, A

    2003-01-01

    An improved method to calculate the gamma-ray buildup factors including bremsstrahlung has been developed. The exposure buildup factors with bremsstrahlung were computer by the present method for lead, iron and water at the source energy of 10.0 MeV up to depths of 100 mfp. The accuracy of the present method was checked by comparison with the calculations by use of EGS4. Excellent agreement was obtained between the calculations by both methods about the exposure buildup factors per energy (energy spectrum of transmitted photons) for lead up to depths of 10 mfp and the ratio of the exposure buildup factor with bremsstrahlung to that without bremsstrahlung for lead, iron and water up to depths of 40 mfp. It is confirmed that the present method has an accuracy sufficient to be used to the generation of an improved set of gamma-ray buildup factors including bremsstrahlung. (author)

  13. Sequence stratigraphy of carbonate buildups developed in an active tectonic/volcanic setting: Triassic (Late Ladinian and Carnian) of the Dolomites, northern Italy

    Energy Technology Data Exchange (ETDEWEB)

    Yose, L.A. (Johns Hopkins Univ., Baltimore, MD (United States)); Littmann, P. (Univ. of Tubingen (Germany))

    1991-03-01

    Late Ladinian and Carnian deposits of the Dolomites record the evolution of carbonate buildups developed during the waning phases of a major period of volcanism and strike-slip tectonics. Each separate buildup provides an independent record of eustasy, tectonism, and competing carbonate and volcaniclastic sedimentation. Palynomorphs, calibrated with ammonites, are used to correlate between buildups and provide a means for distinguishing local variations in buildup histories from regional, synchronous trends in sedimentation which may record third-order eustasy. Although individual buildup histories vary dramatically, two depositional sequences may be recorded at a regional scale: one of late Ladinian age (early to late Longobardian) and another of late Ladinian to middle Carnian age (late Longobardian to Cordevolian). A relative sea-level fall in the late Ladinian resulted in an increased supply of volcaniclastics that onlap the flanks of many buildups and/or downslope shifts in carbonate production. Buildups of the second sequence developed in response to a relative sea-level rise and are similar in diversity to those of the first sequence. Extensive buildup progradation and accretion during this phase, concomitant with mixed-carbonate/volcaniclastic basin filling and diminished tectonic activity, result in a regional suturing of the complex paleogeography developed during the middle Ladinian. Local paleogeography, determined by the distribution of earlier platforms in addition to tectonic and volcanogenic processes, is interpreted as the primary control over buildup geometries and the variability of buildups within sequences. However, the regional extent and synchroneity of the sequences described above many record third-order eustasy.

  14. Build-up and decline of organic matter during PeECE III

    Directory of Open Access Journals (Sweden)

    K. G. Schulz

    2008-05-01

    Full Text Available Increasing atmospheric carbon dioxide (CO2 concentrations due to anthropogenic fossil fuel combustion are currently changing the ocean's chemistry. Increasing oceanic [CO2] and consequently decreasing seawater pH have the potential to significantly impact marine life. Here we describe and analyze the build-up and decline of a natural phytoplankton bloom initiated during the 2005 mesocosm Pelagic Ecosystem CO2 Enrichment study (PeECE III. The draw-down of inorganic nutrients in the upper surface layer of the mesocosms was reflected by a concomitant increase of organic matter until day t11, the peak of the bloom. From then on, biomass standing stocks steadily decreased as more and more particulate organic matter was lost into the deeper layer of the mesocosms. We show that organic carbon export to the deeper layer was significantly enhanced at elevated CO2. This phenomenon might have impacted organic matter remineralization leading to decreased oxygen concentrations in the deeper layer of the high CO2 mesocosms as indicated by deep water ammonium concentrations. This would have important implications for our understanding of pelagic ecosystem functioning and future carbon cycling.

  15. The Build-Up Course of Visuo-Motor and Audio-Motor Temporal Recalibration

    Directory of Open Access Journals (Sweden)

    Yoshimori Sugano

    2011-10-01

    Full Text Available The sensorimotor timing is recalibrated after a brief exposure to a delayed feedback of voluntary actions (temporal recalibration effect: TRE (Heron et al., 2009; Stetson et al., 2006; Sugano et al., 2010. We introduce a new paradigm, namely ‘synchronous tapping’ (ST which allows us to investigate how the TRE builds up during adaptation. In each experimental trial, participants were repeatedly exposed to a constant lag (∼150 ms between their voluntary action (pressing a mouse and a feedback stimulus (a visual flash / an auditory click 10 times. Immediately after that, they performed a ST task with the same stimulus as a pace signal (7 flashes / clicks. A subjective ‘no-delay condition’ (∼50 ms served as control. The TRE manifested itself as a change in the tap-stimulus asynchrony that compensated the exposed lag (eg, after lag adaptation, the tap preceded the stimulus more than in control and built up quickly (∼3–6 trials, ∼23–45 sec in both the visuo- and audio-motor domain. The audio-motor TRE was bigger and built-up faster than the visuo-motor one. To conclude, the TRE is comparable between visuo- and audio-motor domain, though they are slightly different in size and build-up rate.

  16. Prediction of wax buildup in 24 inch cold, deep sea oil loading line

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.; Sattler, R.E.; Tolonen, W.J.; Pitchford, A.C.

    1981-10-01

    When designing pipelines for cold environments, it is important to know how to predict potential problems due to wax deposition on the pipeline's inner surface. The goal of this work was to determine the rate of wax buildup and the maximum, equlibrium wax thickness for a North Sea field loading line. The experimental techniques and results used to evaluate the waxing potential of the crude oil (B) are described. Also, the theoretic model which was used for predicting the maximum wax deposit thickness in the crude oil (B) loading pipeline at controlled temperatures of 40 F (4.4 C) and 100 F (38 C), is illustrated. Included is a recommendation of a procedure for using hot oil at the end of a tanker loading period in order to dewax the crude oil (B) line. This technique would give maximum heating of the pipeline and should be followed by shutting the hot oil into the pipeline at the end of the loading cycle which will provide a hot oil soaking to help soften existing wax. 14 references.

  17. Measurements and Phenomenological Modeling of Magnetic FluxBuildup in Spheromak Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Talamas, C A; Hooper, E B; Jayakumar, R; McLean, H S; Wood, R D; Moller, J M

    2007-12-14

    Internal magnetic field measurements and high-speed imaging at the Sustained Spheromak Physics Experiment (SSPX) [E. B. Hooper, L. D. Pearlstein, R. H. Bulmer, Nucl. Fusion 39, 863 (1999)] are used to study spheromak formation and field buildup. The measurements are analyzed in the context of a phenomenological model of magnetic helicity based on the topological constraint of minimum helicity in the open flux before reconnecting and linking closed flux. Two stages are analyzed: (1) the initial spheromak formation, i. e. when all flux surfaces are initially open and reconnect to form open and closed flux surfaces, and (2) the stepwise increase of closed flux when operating the gun on a new mode that can apply a train of high-current pulses to the plasma. In the first stage, large kinks in the open flux surfaces are observed in the high-speed images taken shortly after plasma breakdown, and coincide with large magnetic asymmetries recorded in a fixed insertable magnetic probe that spans the flux conserver radius. Closed flux (in the toroidal average sense) appears shortly after this. This stage is also investigated using resistive magnetohydrodynamic simulations. In the second stage, a time lag in response between open and closed flux surfaces after each current pulse is interpreted as the time for the open flux to build helicity, before transferring it through reconnection to the closed flux. Large asymmetries are seen during these events, which then relax to a slowly decaying spheromak before the next pulse.

  18. Simulations of the electron cloud buildup and its influence on the microwave transmission measurement

    Science.gov (United States)

    Haas, Oliver Sebastian; Boine-Frankenheim, Oliver; Petrov, Fedor

    2013-11-01

    An electron cloud density in an accelerator can be measured using the Microwave Transmission (MWT) method. The aim of our study is to evaluate the influence of a realistic, nonuniform electron cloud on the MWT. We conduct electron cloud buildup simulations for beam pipe geometries and bunch parameters resembling roughly the conditions in the CERN SPS. For different microwave waveguide modes the phase shift induced by a known electron cloud density is obtained from three different approaches: 3D Particle-In-Cell (PIC) simulation of the electron response, a 2D eigenvalue solver for waveguide modes assuming a dielectric response function for cold electrons, a perturbative method assuming a sufficiently smooth density profile. While several electron cloud parameters, such as temperature, result in minor errors in the determined density, the transversely inhomogeneous density can introduce a large error in the measured electron density. We show that the perturbative approach is sufficient to describe the phase shift under realistic electron cloud conditions. Depending on the geometry of the beam pipe, the external magnetic field configuration and the used waveguide mode, the electron cloud density can be concentrated at the beam pipe or near the beam pipe center, leading to a severe over- or underestimation of the electron density. Electron cloud distributions are very inhomogeneous, especially in dipoles. These inhomogeneities affect the microwave transmission measurement results. Electron density might be over- or underestimated, depending on setup. This can be quantified with several models, e.g. a perturbative approach.

  19. Comparative study of mechanical properties of direct core build-up materials.

    Science.gov (United States)

    Kumar, Girish; Shivrayan, Amit

    2015-01-01

    The strength greatly influences the selection of core material because core must withstand forces due to mastication and para-function for many years. This study was conducted to evaluate certain mechanical properties of commonly used materials for direct core build-up, including visible light cured composite, polyacid modified composite, resin modified glass ionomer, high copper amalgam, and silver cermet cement. All the materials were manipulated according to the manufacturer's recommendations and standard test specimens were prepared. A universal testing machine at different cross-head speed was used to determine all the four mechanical properties. Mean compressive strength, diametral tensile strength, flexural strength, and elastic modulus with standard deviations were calculated. Multiple comparisons of the materials were also done. Considerable differences in compressive strength, diametral tensile strength, and flexural strength were observed. Visible light cured composite showed relatively high compressive strength, diametral tensile strength, and flexural strength compared with the other tested materials. Amalgam showed the highest value for elastic modulus. Silver cermet showed less value for all the properties except for elastic modulus. Strength is one of the most important criteria for selection of a core material. Stronger materials better resist deformation and fracture provide more equitable stress distribution, greater stability, and greater probability of clinical success.

  20. Comparative study of mechanical properties of direct core build-up materials

    Directory of Open Access Journals (Sweden)

    Girish Kumar

    2015-01-01

    Full Text Available Background and Objectives: The strength greatly influences the selection of core material because core must withstand forces due to mastication and para-function for many years. This study was conducted to evaluate certain mechanical properties of commonly used materials for direct core build-up, including visible light cured composite, polyacid modified composite, resin modified glass ionomer, high copper amalgam, and silver cermet cement. Materials and Methods: All the materials were manipulated according to the manufacturer′s recommendations and standard test specimens were prepared. A universal testing machine at different cross-head speed was used to determine all the four mechanical properties. Mean compressive strength, diametral tensile strength, flexural strength, and elastic modulus with standard deviations were calculated. Multiple comparisons of the materials were also done. Results: Considerable differences in compressive strength, diametral tensile strength, and flexural strength were observed. Visible light cured composite showed relatively high compressive strength, diametral tensile strength, and flexural strength compared with the other tested materials. Amalgam showed the highest value for elastic modulus. Silver cermet showed less value for all the properties except for elastic modulus. Conclusions: Strength is one of the most important criteria for selection of a core material. Stronger materials better resist deformation and fracture provide more equitable stress distribution, greater stability, and greater probability of clinical success.

  1. Renewable build-up pathways for the US: Generation costs are not system costs

    CERN Document Server

    Becker, Sarah; Andresen, Gorm B; Jacobson, Mark Z; Schramm, Stefan; Greiner, Martin

    2014-01-01

    The transition to a future electricity system based primarily on wind and solar PV is examined for all regions in the contiguous US. We present optimized pathways for the build-up of wind and solar power for least backup energy needs as well as for least cost obtained with a simplified, lightweight model based on long-term high resolution weather-determined generation data. In the absence of storage, the pathway which achieves the best match of generation and load, thus resulting in the least backup energy requirements, generally favors a combination of both technologies, with a wind/solar PV energy mix of about 80/20 in a fully renewable scenario. The least cost development is seen to start with 100% of the technology with the lowest average generation costs first, but with increasing renewable installations, economically unfavorable excess generation pushes it toward the minimal backup pathway. Surplus generation and the entailed costs can be reduced significantly by combining wind and solar power, and/or a...

  2. Comparison between electron cloud build-up measurements and simulations at the CERN PS

    CERN Document Server

    Caspers, F; Mahner, E; Rumolo, G; Yin Vallgren, C; Iadarola, G

    2012-01-01

    The build up of an Electron Cloud (EC) has been observed at the CERN Proton Synchrotron (PS) during the last stages of the LHC high intensity beam preparation, especially after the bunch shortening before extraction. Two dedicated EC experiments, both equipped with two button pick-ups, a pressure gauge, a clearing electrode and a small dipole magnet, are available in two straight sections of the machine. A measurement campaign has been carried out, in order to scan the EC build-up of LHC-type beams with different bunch spacing, bunch intensity and bunch length. Such information, combined with the results from build up simulations, is of relevance for the characterization in terms of Secondary Emission Yield (SEY) of the chamber inner surface. The interest is twofold: this will enable us to predict the EC build up distribution in the PS for higher intensity beams in the frame of the upgrade program, and it will provide validation of the EC simulation models and codes.

  3. Determination of attenuation parameters and energy absorption build-up factor of amine group materials

    Science.gov (United States)

    Lokhande, Rajkumar M.; More, Chaitali V.; Surung, Bharat S.; Pawar, Pravina P.

    2017-12-01

    We have computed radiological parameters of some C- H- N- O based amine group bio material in the energy range 122-1330 keV with the gamma ray count by narrow beam geometry. The NaI(Tl) detector with 8 K multichannel analyser was used having resolution 6.8% at 663 keV. The energy absorption buildup factor (EABF) was determined by using Geometric Progression (G-P) fitting method up to penetration depth of 40 mfp at energy 0.015-15 MeV. The NIST XCOM data were compared with the experimental value and we observed (3-5%) difference. The comparative study of effective atomic number and effective electron density in the energy range 122-1330 keV using Gaussian fit for accuracy were performed. The amino acid has the highest EABF value at 0.1 MeV and the variation in EABF with penetration depth up to 1-40 mean free path (mfp). The calculated radiological data of biological material are applicable in medical physics and dosimetry.

  4. Influence of light intensity on surface free energy and dentin bond strength of core build-up resins.

    Science.gov (United States)

    Shimizu, Y; Tsujimoto, A; Furuichi, T; Suzuki, T; Tsubota, K; Miyazaki, M; Platt, J A

    2015-01-01

    We examined the influence of light intensity on surface free energy characteristics and dentin bond strength of dual-cure direct core build-up resin systems. Two commercially available dual-cure direct core build-up resin systems, Clearfil DC Core Automix with Clearfil Bond SE One and UniFil Core EM with Self-Etching Bond, were studied. Bovine mandibular incisors were mounted in acrylic resin and the facial dentin surfaces were wet ground on 600-grit silicon carbide paper. Adhesives were applied to dentin surfaces and cured with light intensities of 0 (no irradiation), 200, 400, and 600 mW/cm(2). The surface free energy of the adhesives (five samples per group) was determined by measuring the contact angles of three test liquids placed on the cured adhesives. To determine the strength of the dentin bond, the core build-up resin pastes were condensed into the mold on the adhesive-treated dentin surfaces according to the methods described for the surface free energy measurement. The resin pastes were cured with the same light intensities as those used for the adhesives. Ten specimens per group were stored in water maintained at 37°C for 24 hours, after which they were shear tested at a crosshead speed of 1.0 mm/minute in a universal testing machine. Two-way analysis of variance (ANOVA) and a Tukey-Kramer test were performed, with the significance level set at 0.05. The surface free energies of the adhesive-treated dentin surfaces decreased with an increase in the light intensity of the curing unit. Two-way ANOVA revealed that the type of core build-up system and the light intensity significantly influence the bond strength, although there was no significant interaction between the two factors. The highest bond strengths were achieved when the resin pastes were cured with the strongest light intensity for all the core build-up systems. When polymerized with a light intensity of 200 mW/cm(2) or less, significantly lower bond strengths were observed. CONClUSIONS: The

  5. Determination of buildup and dilution of wastewater effluent in shellfish growing waters through a modified application of super-position.

    Science.gov (United States)

    Goblick, Gregory N; Ao, Yaping; Anbarchian, Julie M; Calci, Kevin R

    2017-02-15

    Since 1925, dilution analysis has been used to minimize pathogenic impacts to bivalve molluscan shellfish growing areas from treated wastewater effluent in the National Shellfish Sanitation Program (NSSP). For over twenty five years, the U.S. Food and Drug Administration (FDA) has recommended a minimum of 1000:1 dilution of effluent within prohibited closure zones established around wastewater treatment plant (WWTP) discharges. During May 2010, using recent technologies, a hydrographic dye study was conducted in conjunction with a pathogen bioaccumulation study in shellfish adjacent to a WWTP discharge in Yarmouth, ME. For the first time an improved method of the super-position principle was used to determine the buildup of dye tagged sewage effluent and steady state dilution in tidal waters. Results of the improved method of dilution analysis illustrate an economical, reliable and more accurate and manageable approach for estimating the buildup and steady state pollutant conditions in coastal and estuarine waters. Published by Elsevier Ltd.

  6. SU-E-T-59: Calculations of Collimator Scatter Factors (Sc) with and Without Custom-Made Build-Up Caps for CyberKnife

    Energy Technology Data Exchange (ETDEWEB)

    Wokoma, S; Yoon, J; Jung, J [East Carolina University, Greenville, NC (United States); Lee, S [Rhode Island Hospital / Warren Alpert Medical, Providence, RI (United States)

    2014-06-01

    Purpose: To investigate the impact of custom-made build-up caps for a diode detector in robotic radiosurgery radiation fields with variable collimator (IRIS) for collimator scatter factor (Sc) calculation. Methods: An acrylic cap was custom-made to fit our SFD (IBA Dosimetry, Germany) diode detector. The cap has thickness of 5 cm, corresponding to a depth beyond electron contamination. IAEA phase space data was used for beam modeling and DOSRZnrc code was used to model the detector. The detector was positioned at 80 cm source-to-detector distance. Calculations were performed with the SFD, with and without the build-up cap, for clinical IRIS settings ranging from 7.5 to 60 mm. Results: The collimator scatter factors were calculated with and without 5 cm build-up cap. They were agreed within 3% difference except 15 mm cone. The Sc factor for 15 mm cone without buildup was 13.2% lower than that with buildup. Conclusion: Sc data is a critical component in advanced algorithms for treatment planning in order to calculate the dose accurately. After incorporating build-up cap, we discovered differences of up to 13.2 % in Sc factors in the SFD detector, when compared against in-air measurements without build-up caps.

  7. Venom Immunotherapy in High-Risk Patients: The Advantage of the Rush Build-Up Protocol.

    Science.gov (United States)

    Rosman, Yossi; Confino-Cohen, Ronit; Goldberg, Arnon

    2017-01-01

    Venom immunotherapy (VIT) is considered to be the gold standard treatment for patients with hymenoptera venom allergy. This treatment induces systemic reactions (SR) in a significant number of patients. To evaluate the outcome of VIT in patients with known risk factors for VIT-induced SR and to compare rush VIT (RVIT) and conventional VIT (CVIT). All of the patients who received VIT and had at least one of the following risk factors were included: current cardiovascular disease, uncontrolled asthma, high basal serum tryptase, current treatment with β-blockers or angiotensin-converting enzyme inhibitors, and age >70 or <5 years. Sixty-four patients were included, and most of them (52; 81.5%) were allergic exclusively to bee venom. Thirty-five (54.7%) patients underwent RVIT and 29 CVIT. The incidence of patients who developed SR during the build-up phase was similar for RVIT and CVIT (25.7 and 27.5%, respectively; p = 1). However, the incidence of SR per injection was significantly higher in CVIT than in RVIT (5.6 and 2.75%, respectively; p = 0.01). Most reactions (79.1%) were mild, limited to the skin. Most of the patients (92.1%) reached the full maintenance dose of 100 μg. This dose was reached by a significantly larger number of patients receiving RVIT compared to CVIT (100 and 82.7%, respectively; p = 0.01). None of the patients experienced exacerbation of their concurrent chronic disease during VIT. VIT can be performed safely and efficiently in patients with risk factors for immunotherapy. In these patients RVIT appears to be safer and more efficient than CVIT. © 2017 S. Karger AG, Basel.

  8. Deposit buildup on prosthetic eye material (in vitro) and its effect on surface wettability.

    Science.gov (United States)

    Pine, Keith Raymond; Sloan, Brian; Han, Kyuyeon Ivy; Swift, Simon; Jacobs, Robert John

    2013-01-01

    The aim of this in-vitro study was to investigate the effect of different polishing standards on prosthetic eye material (poly(methyl methacrylate) [PMMA]) on surface wettability and the rate of protein and lipid buildup. Sample disks (12 mm diameter × 1 mm thickness) of PMMA were polished to three different standards of surface finish: low, normal, and optical quality contact lens standard. The sample disks were incubated in a protein-rich artificial tear solution (ATS) for the following periods of time: 1 second, 30 minutes, 1 hour, 4 hours, 24 hours, and 14 days. Surface wettability was measured with a goniometer before and after protein deposits were removed. One-way analysis of variance and paired-samples t-test were used for the statistical analysis. Between 13.64 and 62.88 μg of protein adhered to the sample disks immediately upon immersion in ATS. Sample disks with the highest polish attracted less protein deposits. The sample disks polished to optical quality contact lens standard were more wettable than those less highly polished, and wettability significantly decreased following removal of protein deposits. The addition of lipids to protein-only ATS made no difference to the amount of protein deposited on the sample disks for any of the standards of surface polish tested. The findings are consistent with the results of the in-vivo investigation reported previously by the authors. Our view that the minimum standard of polish for prosthetic eyes should be optical quality contact lens standard and that deposits on PMMA prosthetic eyes improve the lubricating properties of the socket fluids has been reinforced by the results of this study.

  9. Deposit buildup on prosthetic eyes and implications for conjunctival inflammation and mucoid discharge.

    Science.gov (United States)

    Pine, Keith Raymond; Sloan, Brian; Jacobs, Robert John

    2012-01-01

    The aim of this study was to investigate deposit buildup on prosthetic eyes and the implications for conjunctival inflammation and discharge. Forty-three prosthetic eye wearers participated in the study. Twenty-three had their prostheses polished normally before being worn continuously for 2 weeks. After this time, surface deposits were stained, photographed, and graded. The prostheses were then repolished to optical quality contact lens standard and worn for a further 2 weeks, when the deposits were again stained, photographed, and graded. Two participants had deposits on their prostheses stained, photographed, and graded on nine occasions at decreasing intervals ranging from 1 year to 1 day. Eighteen participants had the wetting angles on their prostheses measured with a goniometer before and after cleaning, after polishing normally, after polishing to optical quality contact lens standard, and after 10 minutes of wearing their optical quality contact lens polished prostheses. Concordance correlation, multiple regression, and paired t-tests were used for the statistical analysis. More surface deposits accumulated on prostheses polished normally than on those polished to an optical quality contact lens standard after 2 weeks of wear. The interpalpebral zone of most prostheses (observed without magnification) appeared to be clear of deposits. Removal of deposits significantly decreased surface wettability, but wettability returned after 10 minutes of wear. Optical quality contact lens polishing produced more wettable surfaces and a slower rate of deposit accumulation than normal polishing. We recommend that an optical quality contact lens standard be the minimum standard of finish for prosthetic eyes. This standard may assist the smooth action of the lids over the interpalpebral zone of the prosthesis and the cleansing action of tears. The presence of deposits in the retropalpebral zone may improve the lubricating properties of socket fluids which, in turn, may

  10. Clinical comparison of various esthetic restorative options for coronal build-up of primary anterior teeth

    Directory of Open Access Journals (Sweden)

    Himanshu Duhan

    2015-01-01

    Full Text Available Background: This study was designed to compare the clinical performance of composite, strip crowns, biological restoration, and composite with stainless steel band when used for the coronal build-up of anterior teeth. Materials and Methods: A total of 20 patients aged 3-6 years presenting with mutilated primary anterior teeth due to caries or trauma were selected for the study using randomized simple sampling. A total of 52 primary anterior teeth were randomly divided into four equal groups having 13 teeth in each group. Teeth in Group I were restored with composite, in Group II with strip crowns, in Group III with biologic restoration and with stainless steel band reinforced composite in group IV. The restorations were evaluated for color match, retention, surface texture, and anatomic form according to Ryge′s Direct (US Public Health Service evaluation criteria at baseline (immediate postoperative, after 48 h, 3, 6, and 9 months. The data obtained were statistically analyzed using Chi-square test, and level of significance, that is, P value was determined. Results: At baseline, none of the groups showed any color changes. Other than Group III all other groups showed highly significant changes (P 0.05. Deterioration in surface texture was exhibited maximum by restorations in Group IV followed by Group I at 3 months. Whereas, no surface changes were seen in Group II and III. Only Group I and IV showed discontinuity in anatomic form after 3 months. After 6 months, except in Group II, discontinuity in anatomic form was observed in all the groups. Discontinuity in anatomic form was seen in all the 4 groups after 9 months although the difference was not significant (P > 0.05. Conclusion: Biological restoration was found to be most satisfying esthetically owing to color compatibility with the patient′s tooth. Thus, it has a great potential to be used as esthetic restorative option in primary anteriors.

  11. Clinical comparison of various esthetic restorative options for coronal build-up of primary anterior teeth

    Science.gov (United States)

    Duhan, Himanshu; Pandit, Inder Kumar; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika; Kochhar, Gulsheen Kaur

    2015-01-01

    Background: This study was designed to compare the clinical performance of composite, strip crowns, biological restoration, and composite with stainless steel band when used for the coronal build-up of anterior teeth. Materials and Methods: A total of 20 patients aged 3-6 years presenting with mutilated primary anterior teeth due to caries or trauma were selected for the study using randomized simple sampling. A total of 52 primary anterior teeth were randomly divided into four equal groups having 13 teeth in each group. Teeth in Group I were restored with composite, in Group II with strip crowns, in Group III with biologic restoration and with stainless steel band reinforced composite in group IV. The restorations were evaluated for color match, retention, surface texture, and anatomic form according to Ryge's Direct (US Public Health Service) evaluation criteria at baseline (immediate postoperative), after 48 h, 3, 6, and 9 months. The data obtained were statistically analyzed using Chi-square test, and level of significance, that is, P value was determined. Results: At baseline, none of the groups showed any color changes. Other than Group III all other groups showed highly significant changes (P 0.05). Deterioration in surface texture was exhibited maximum by restorations in Group IV followed by Group I at 3 months. Whereas, no surface changes were seen in Group II and III. Only Group I and IV showed discontinuity in anatomic form after 3 months. After 6 months, except in Group II, discontinuity in anatomic form was observed in all the groups. Discontinuity in anatomic form was seen in all the 4 groups after 9 months although the difference was not significant (P > 0.05). Conclusion: Biological restoration was found to be most satisfying esthetically owing to color compatibility with the patient's tooth. Thus, it has a great potential to be used as esthetic restorative option in primary anteriors. PMID:26759595

  12. Clinical comparison of various esthetic restorative options for coronal build-up of primary anterior teeth.

    Science.gov (United States)

    Duhan, Himanshu; Pandit, Inder Kumar; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika; Kochhar, Gulsheen Kaur

    2015-01-01

    This study was designed to compare the clinical performance of composite, strip crowns, biological restoration, and composite with stainless steel band when used for the coronal build-up of anterior teeth. A total of 20 patients aged 3-6 years presenting with mutilated primary anterior teeth due to caries or trauma were selected for the study using randomized simple sampling. A total of 52 primary anterior teeth were randomly divided into four equal groups having 13 teeth in each group. Teeth in Group I were restored with composite, in Group II with strip crowns, in Group III with biologic restoration and with stainless steel band reinforced composite in group IV. The restorations were evaluated for color match, retention, surface texture, and anatomic form according to Ryge's Direct (US Public Health Service) evaluation criteria at baseline (immediate postoperative), after 48 h, 3, 6, and 9 months. The data obtained were statistically analyzed using Chi-square test, and level of significance, that is, P value was determined. At baseline, none of the groups showed any color changes. Other than Group III all other groups showed highly significant changes (P 0.05). Deterioration in surface texture was exhibited maximum by restorations in Group IV followed by Group I at 3 months. Whereas, no surface changes were seen in Group II and III. Only Group I and IV showed discontinuity in anatomic form after 3 months. After 6 months, except in Group II, discontinuity in anatomic form was observed in all the groups. Discontinuity in anatomic form was seen in all the 4 groups after 9 months although the difference was not significant (P > 0.05). Biological restoration was found to be most satisfying esthetically owing to color compatibility with the patient's tooth. Thus, it has a great potential to be used as esthetic restorative option in primary anteriors.

  13. Deposit buildup on prosthetic eyes and implications for conjunctival inflammation and mucoid discharge

    Science.gov (United States)

    Pine, Keith Raymond; Sloan, Brian; Jacobs, Robert John

    2012-01-01

    Background The aim of this study was to investigate deposit buildup on prosthetic eyes and the implications for conjunctival inflammation and discharge. Methods Forty-three prosthetic eye wearers participated in the study. Twenty-three had their prostheses polished normally before being worn continuously for 2 weeks. After this time, surface deposits were stained, photographed, and graded. The prostheses were then repolished to optical quality contact lens standard and worn for a further 2 weeks, when the deposits were again stained, photographed, and graded. Two participants had deposits on their prostheses stained, photographed, and graded on nine occasions at decreasing intervals ranging from 1 year to 1 day. Eighteen participants had the wetting angles on their prostheses measured with a goniometer before and after cleaning, after polishing normally, after polishing to optical quality contact lens standard, and after 10 minutes of wearing their optical quality contact lens polished prostheses. Concordance correlation, multiple regression, and paired t-tests were used for the statistical analysis. Results More surface deposits accumulated on prostheses polished normally than on those polished to an optical quality contact lens standard after 2 weeks of wear. The interpalpebral zone of most prostheses (observed without magnification) appeared to be clear of deposits. Removal of deposits significantly decreased surface wettability, but wettability returned after 10 minutes of wear. Optical quality contact lens polishing produced more wettable surfaces and a slower rate of deposit accumulation than normal polishing. Conclusion We recommend that an optical quality contact lens standard be the minimum standard of finish for prosthetic eyes. This standard may assist the smooth action of the lids over the interpalpebral zone of the prosthesis and the cleansing action of tears. The presence of deposits in the retropalpebral zone may improve the lubricating properties of

  14. The Effect of Cyclic Loading on the Compressive Strength of Core Build-Up Materials.

    Science.gov (United States)

    Zankuli, Muayed A; Silikas, Nick; Devlin, Hugh

    2015-01-15

    To evaluate the effect of cyclic loading on compressive strength of core build-up materials. Four dual-cured composites (Core.X Flow, Grandio Core, Bright Flow Core, Spee-Dee) and one light-cured reinforced resin-modified glass ionomer (Fuji II LC) were tested. One hundred cylindrical specimens (4 mm × 6 mm) were prepared. Each material had two groups (ten specimens to be tested under static loading and ten specimens to be tested after cyclic loading). The specimens were stored wet, and after 30 days, one group of each material was cyclically loaded (for 250,000 cycles with a frequency of 1.6 Hz under stress load of 68.6 N) in a chewing simulator CS-4.2. Then specimens were subjected to static compressive loading until failure in a universal testing machine. Mean compressive strength values before cycling ranged from 144 MPa (15.8) for Fuji II LC to 277 MPa (23.2) for Grandio Core. Independent t-test showed no statistically significant difference (p > 0.05) in the compressive strength of each material before and after cycling (p = 0.7 Grandio Core, p = 0.3 Core.X Flow, p = 0.6 Bright Flow Core, p = 0.2 Spee-Dee, p = 0.6 Fuji II LC); however, there was a statistically significant difference between the materials when comparing before and after cycling. All tested materials showed no reduction in the compressive strength after cycling. Therefore, the tested materials can survive 1 year in service without a reduction in compressive strength. © 2015 by the American College of Prosthodontists.

  15. Absorption ratio of treatment couch and effect on surface and build-up region doses.

    Science.gov (United States)

    Tuğrul, Taylan

    2018-01-01

    In this study, at different fields, energies and gantry angles, treatment couch and rails dose absorption ratio and treatment couch effect on surface and build-up region doses were examined. It is assumed that radiation attenuation is minimal because the carbon fiber couches have low density and it is not generally accounted for during treatment planning. Consequently, it leads to a major dosimetric mistake. Solid water phantom was used for relative dose measurement. The measurements were done using a Farmer ion chamber with 0.6 cc volume and a parallel plane ion chamber starting from surface with 1 mm depth intervals at 10 × 10 cm2 field, SSD 100 cm. Measurements were taken for situations where the beams intersect the couch and couch rails. Dose absorption ratio of carbon fiber couch obtained at gantry angle of 180° was 1.52%, 0.69%, 0.33% and 0.25% at different field sizes for 6 MV. For 15 MV, this ratio was 0.95%, 0.27%, 0.20% and 0.05%. The absorption ratio is between 3.4% and 1.22% when the beams intersect with couch rails. The couch effect increased surface dose from 14% to 70% for 6 MV and from 11.34% to 53.03% for 15 MV. The results showed that the carbon fiber couch increased surface dose during posterior irradiation. Therefore, the skin-sparing effect of the high energy beams was decreased. If the effect of couch is not considered, it may cause significant differences at dose which reaches the patient and may cause tissue problems such as erythema.

  16. Simulations of the electron cloud buildup and its influence on the microwave transmission measurement

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Oliver Sebastian, E-mail: o.haas@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Boine-Frankenheim, Oliver [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Schlossgartenstraße 8, 64289 Darmstadt (Germany); Petrov, Fedor [Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Schlossgartenstraße 8, 64289 Darmstadt (Germany)

    2013-11-21

    An electron cloud density in an accelerator can be measured using the Microwave Transmission (MWT) method. The aim of our study is to evaluate the influence of a realistic, nonuniform electron cloud on the MWT. We conduct electron cloud buildup simulations for beam pipe geometries and bunch parameters resembling roughly the conditions in the CERN SPS. For different microwave waveguide modes the phase shift induced by a known electron cloud density is obtained from three different approaches: 3D Particle-In-Cell (PIC) simulation of the electron response, a 2D eigenvalue solver for waveguide modes assuming a dielectric response function for cold electrons, a perturbative method assuming a sufficiently smooth density profile. While several electron cloud parameters, such as temperature, result in minor errors in the determined density, the transversely inhomogeneous density can introduce a large error in the measured electron density. We show that the perturbative approach is sufficient to describe the phase shift under realistic electron cloud conditions. Depending on the geometry of the beam pipe, the external magnetic field configuration and the used waveguide mode, the electron cloud density can be concentrated at the beam pipe or near the beam pipe center, leading to a severe over- or underestimation of the electron density. -- Author-Highlights: •Electron cloud distributions are very inhomogeneous, especially in dipoles. •These inhomogeneities affect the microwave transmission measurement results. •Electron density might be over- or underestimated, depending on setup. •This can be quantified with several models, e.g. a perturbative approach.

  17. Can captive orangutans (Pongo pygmaeus abelii) be coaxed into cumulative build-up of techniques?

    Science.gov (United States)

    Lehner, Stephan R; Burkart, Judith M; Schaik, Carel P van

    2011-11-01

    While striking cultural variation in behavior from one site to another has been described in chimpanzees and orangutans, cumulative culture might be unique to humans. Captive chimpanzees were recently found to be rather conservative, sticking to the technique they had mastered, even after more effective alternatives were demonstrated. Behavioral flexibility in problem solving, in the sense of acquiring new solutions after having learned another one earlier, is a vital prerequisite for cumulative build-up of techniques. Here, we experimentally investigate whether captive orangutans show such flexibility, and if so, whether they show techniques that cumulatively build up (ratchet) on previous ones after conditions of the task are changed. We provided nine Sumatran orangutans (Pongo pygmaeus abelii) with two types of transparent tubes partly filled with syrup, along with potential tools such as sticks, twigs, wood wool and paper. In the first phase, the orangutans could reach inside the tubes with their hands (Regular Condition), but in the following phase, tubes had been made too narrow for their hands to fit in (Restricted Condition 1), or in addition the setup lacked their favorite materials (Restricted Condition 2). The orangutans showed high behavioral flexibility, applying nine different techniques under the regular condition in total. Individuals abandoned preferred techniques and switched to different techniques under restricted conditions when this was advantageous. We show for two of these techniques how they cumulatively built up on earlier ones. This suggests that the near-absence of cumulative culture in wild orangutans is not due to a lack of flexibility when existing solutions to tasks are made impossible.

  18. Immunological and clinical factors associated with adverse systemic reactions during the build-up phase of honeybee venom immunotherapy.

    Science.gov (United States)

    Korošec, P; Žiberna, K; Šilar, M; Dežman, M; Čelesnik Smodiš, N; Rijavec, M; Kopač, P; Eržen, R; Lalek, N; Bajrović, N; Košnik, M; Zidarn, M

    2015-10-01

    Adverse systemic reactions (SRs) are more common in honeybee venom immunotherapy (VIT) than in wasp VIT. Factors that might be associated with SRs during the honeybee VIT are poorly understood. Our aim was to evaluate risk factors for SRs during the build-up phase of honeybee venom immunotherapy. We included 93 patients who underwent ultra-rush honeybee VIT. The adverse SRs and their severity was compared to various immunological (sIgE, tIgE, basophil CD63 response, baseline tryptase, and skin tests), patient-specific (age, sex, cardiovascular conditions and medications, and other allergic diseases), and sting-specific factors (anaphylaxis severity, time interval to onset of symptoms, and absence of cutaneous symptoms). Twenty-three patients (24.7%) experienced mild SRs and 13 patients (14%) severe SRs. In five patients with severe SRs, the build-up was stopped. High basophil allergen sensitivity, evaluated as dose-response curve metrics of EC15, EC50, CD-sens, AUC, or the response to submaximal 0.01 μg/mL of venom concentration, was the most significant risk factor and only independent predictor of severe SRs and/or build-up stop. Time interval of build-up phase of honeybee VIT. Possibly role was also showed for short latency to filed sting reaction and low sIgE to rApi m1. Before honeybee VIT, measurement of basophil allergen sensitivity should be used to identify patients with a high risk for severe side-effects. © 2015 John Wiley & Sons Ltd.

  19. A comprehensive study of the energy absorption and exposure buildup factors of different bricks for gamma-rays shielding

    Directory of Open Access Journals (Sweden)

    M.I. Sayyed

    Full Text Available The present investigation has been performed on different bricks for the purpose of gamma-ray shielding. The values of the mass attenuation coefficient (µ/ρ, energy absorption buildup factor (EABF and exposure buildup factor (EBF were determined and utilized to assess the shielding effectiveness of the bricks under investigation. The mass attenuation coefficients of the selected bricks were calculated theoretically using WinXcom program and compared with MCNPX code. Good agreement between WinXcom and MCNPX results was observed. Furthermore, the EABF and EBF have been discussed as functions of the incident photon energy and penetration depth. It has been found that the EABF and EBF values are very large in the intermediate energy region. The steel slag showed good shielding properties, consequently, this brick is eco-friendly and feasible compared with other types of bricks used for construction. The results in this work should be useful in the construction of effectual shielding against hazardous gamma-rays. Keywords: Brick, Mass attenuation coefficient, Buildup factor, G-P fitting, Radiation shielding

  20. Evaluation of Geometric Progression (GP Buildup Factors using MCNP Codes (MCNP6.1 and MCNP5-1.60

    Directory of Open Access Journals (Sweden)

    Kim Kyung-O

    2016-01-01

    Full Text Available The gamma-ray buildup factors of three-dimensional point kernel code (QAD-CGGP are re-evaluated by using MCNP codes (MCNP6.1 and MCNPX5-1.60 and ENDF/B-VI.8 photoatomic data, which cover an energy range of 0.015–15 MeV and an iron thickness of 0.5–40 Mean Free Path (MFP. These new data are fitted to the Geometric Progression (GP fitting function and are then compared with ANS standard data equipped with QAD-CGGP. In addition, a simple benchmark calculation was performed to compare the QAD-CGGP results applied with new and existing buildup factors based on the MCNP codes. In the case of the buildup factors of low-energy gamma-rays, new data are evaluated to be about 5% higher than the existing data. In other cases, these new data present a similar trend based on the specific penetration depth, while existing data continuously increase beyond that depth. In a simple benchmark, the calculations using the existing data were slightly underestimated compared to the reference data at a deep penetration depth. On the other hand, the calculations with new data were stabilized with an increasing penetration depth, despite a slight overestimation at a shallow penetration depth.

  1. Composite Resin Core Buildups With and Without Post for the Restoration of Endodontically Treated Molars Without Ferrule.

    Science.gov (United States)

    Magne, P; Goldberg, J; Edelhoff, D; Güth, J-F

    2016-01-01

    The aim of this study was to investigate the restoration of highly damaged, broken-down endodontically treated molars without the ferrule effect using glass ceramic crowns on different dual-cure composite resin core buildups. Thirty (N=30, n=15) decoronated, endodontically treated teeth (no ferrule) were restored without a ferrule with a direct buildup using the dual-curing composite Multicore HB (group MHB) or the dual-curing composite core buildup Multicore Flow in combination with glass-fiber-reinforced composite post (FRC post; group MFP). All teeth were prepared to receive bonded glass ceramic crowns (Empress CAD luted with Variolink II) and were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the palatal cusp at an angle of 30 degrees and a frequency of 5 Hz, beginning with a load of 200 N (×5000 cycles), followed by stages of 400, 600, 800, 1000, 1200, and 1400 N at a maximum of 30,000 cycles each. Specimens were loaded until failure or to a maximum of 185,000 cycles. Groups were compared using the life table survival analysis (log rank test at p=0.05). Average fracture loads and number of survived cycles were compared with one-way analysis of variance (Scheffé post hoc at p=0.05). Previously published data from the same authors about core buildups made of high-performance polymers (group HPP, n=15) and light-curing composite resin without FRC posts (group TEC, n=15) and with FRC posts (group TECP, n=15) using the same experimental setup were included for comparison. None of the tested specimen withstood all 185,000 load cycles. There was no significant difference in mean fracture load (p=0.376), survived cycles (p=0.422), and survival (p=0.613) between MHB (facture load 859.4 N±194.92) and MFP (796.13 N±156.34). Group HPP from a previous study appeared to have significantly higher performance than all other groups except MHB. All groups with posts were affected by an initial failure phenomenon (wide gap at the margin

  2. Deposit buildup on prosthetic eye material (in vitro and its effect on surface wettability

    Directory of Open Access Journals (Sweden)

    Pine KR

    2013-02-01

    Full Text Available Keith Raymond Pine,1 Brian Sloan,2 KyuYeon Ivy Han,1 Simon Swift,3 Robert John Jacobs11Department of Optometry and Vision Science, New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand; 2New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand; 3Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland, New ZealandBackground: The aim of this in-vitro study was to investigate the effect of different polishing standards on prosthetic eye material (poly(methyl methacrylate [PMMA] on surface wettability and the rate of protein and lipid buildup.Methods: Sample disks (12 mm diameter × 1 mm thickness of PMMA were polished to three different standards of surface finish: low, normal, and optical quality contact lens standard. The sample disks were incubated in a protein-rich artificial tear solution (ATS for the following periods of time: 1 second, 30 minutes, 1 hour, 4 hours, 24 hours, and 14 days. Surface wettability was measured with a goniometer before and after protein deposits were removed. One-way analysis of variance and paired-samples t-test were used for the statistical analysis.Results: Between 13.64 and 62.88 µg of protein adhered to the sample disks immediately upon immersion in ATS. Sample disks with the highest polish attracted less protein deposits. The sample disks polished to optical quality contact lens standard were more wettable than those less highly polished, and wettability significantly decreased following removal of protein deposits. The addition of lipids to protein-only ATS made no difference to the amount of protein deposited on the sample disks for any of the standards of surface polish tested.Conclusion: The findings are consistent with the results of the in-vivo investigation reported previously by the authors. Our view that the minimum standard of polish for prosthetic eyes should be optical quality contact

  3. Holocene beach buildup and coastal aeolian sand incursions off the Nile littoral cell

    Science.gov (United States)

    Roskin, Joel; Sivan, Dorit; Shtienberg, Gilad; Porat, Naomi; Bookman, Revital

    2017-04-01

    Israel's coastal plain is abundant with sand originating from the Nile littoral cell. The inland windblown loose sand has formed 3-6 km wide lobe-like sand and dune fields currently comprised of foredunes, linear and northeasterly facing transverse and parabolic dunes that are currently stabilized by vegetation. This study reviews the architecture and history of the these dune fields aiming to: (a) Date the timings of beach accretion, and sand and dune incursions. (b) Discriminate between natural and human-induced forcing factors of sand mobilization and stabilization in time and space. (c) Present a model of the dunescape development. (d) Assess scenarios of sand transport in the future charcaterized by intense human impact and climate change. Luminescence ages, radiocarbon dates and relative ages from previously published geological and archaeological reports, historical texts, together with new optically stimulated luminescence (OSL) ages and stratigraphic and sedimentological data are analyzed. The deposition, mobilizations and preservation of the sand bodies, initially induced by the decline in sea level rise at 6-4 ka, were later controlled by historic land-use intensity and modern land-use/negligence practices. At 6 ka, beach sand buildup rapidly started. Where aeolianite ridges bordered the coast, pulses of sand with biogenic carbonate grains unconformably draped the ridges and rapidly consolidated into a distinct sandy calcarenite unit. Further east, sand sheets and low dunes partly pedogenized following their incursion, but did not cement. The water retention capacities of the sand sheets enabled the establishment of a sand-stabilizing vegetation cover that probably became an attractive environment for fuel and grazing. The growing Hellenistic-Roman-Byzantine ( 2.4-1.3 ka) populations probably led to increased consumption and massive destruction of sand stabilizing vegetation, enabling sand erodibility and mobilization during winter storms. The sand

  4. Investigation of human teeth with respect to the photon interaction, energy absorption and buildup factor

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.co [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Topcuoglu, Sinan [Faculty of Dentistry, Department of Endodontic, Ataturk University, 25240 Erzurum (Turkey)

    2011-05-15

    The effective atomic numbers and electron densities of human teeth have been calculated for total photon interaction (Z{sub PI{sub e{sub f{sub f}}}},Ne{sub PI{sub e{sub f{sub f}}}}) and photon energy absorption (Z{sub PEA{sub e{sub f{sub f}}}},Z{sub RW{sub e{sub f{sub f}}}}Ne{sub PEA{sub e{sub f{sub f}}}}) in the energy region 1 keV-20 MeV. Besides, the energy absorption (EABF) and exposure (EBF) buildup factors have been calculated for these samples by using the geometric progression fitting approximation in the energy region 0.015-15 MeV up to 40 mfp (mean free path). Wherever possible the results were compared with experiment. Effective atomic numbers (Z{sub PI{sub e{sub f{sub f}}}}) of human teeth were calculated using different methods. Discrepancies were noted in Z{sub PI{sub e{sub f{sub f}}}} between the direct and interpolation methods in the low and high energy regions where absorption processes dominate while good agreement was observed in intermediate energy region where Compton scattering dominates. Significant variations up to 22% were observed between Z{sub PI{sub e{sub f{sub f}}}} and Z{sub PEA{sub e{sub f{sub f}}}} in the energy region 30-150 keV which is the used energy range in dental cone beam computed tomography (CBCT) X-ray machines. The Z{sub eff} values of human teeth were found to relatively vary within 1% if different laser treatments are applied. In this variation, the Er:YAG laser treated samples were found to be less effected than Nd:YAG laser treated ones when compared with control group. Relative differences between EABF and EBF were found to be significantly high in the energy region 60 keV-1 MeV even though they have similar variations with respect to the different parameters viz. photon energy, penetration depth.

  5. Deposit buildup on prosthetic eyes and implications for conjunctival inflammation and mucoid discharge

    Directory of Open Access Journals (Sweden)

    Pine KR

    2012-10-01

    Full Text Available Keith Raymond Pine,1 Brian Sloan,2 Robert John Jacobs11Department of Optometry and Vision Science, 2New Zealand National Eye Centre, The University of Auckland, Auckland, New ZealandBackground: The aim of this study was to investigate deposit buildup on prosthetic eyes and the implications for conjunctival inflammation and discharge.Methods: Forty-three prosthetic eye wearers participated in the study. Twenty-three had their prostheses polished normally before being worn continuously for 2 weeks. After this time, surface deposits were stained, photographed, and graded. The prostheses were then repolished to optical quality contact lens standard and worn for a further 2 weeks, when the deposits were again stained, photographed, and graded. Two participants had deposits on their prostheses stained, photographed, and graded on nine occasions at decreasing intervals ranging from 1 year to 1 day. Eighteen participants had the wetting angles on their prostheses measured with a goniometer before and after cleaning, after polishing normally, after polishing to optical quality contact lens standard, and after 10 minutes of wearing their optical quality contact lens polished prostheses. Concordance correlation, multiple regression, and paired t-tests were used for the statistical analysis.Results: More surface deposits accumulated on prostheses polished normally than on those polished to an optical quality contact lens standard after 2 weeks of wear. The interpalpebral zone of most prostheses (observed without magnification appeared to be clear of deposits. Removal of deposits significantly decreased surface wettability, but wettability returned after 10 minutes of wear. Optical quality contact lens polishing produced more wettable surfaces and a slower rate of deposit accumulation than normal polishing.Conclusion: We recommend that an optical quality contact lens standard be the minimum standard of finish for prosthetic eyes. This standard may assist the

  6. Aphanitic buildup from the onset of the Mulde Event (Homerian, middle Silurian at Whitman's Hill, Herefordshire, UK: ultrastructural insights into proposed microbial fabrics

    Directory of Open Access Journals (Sweden)

    Jan-Filip Päßler

    2014-12-01

    Full Text Available A microbial origin has been proposed for matrix-supported, low-diversity buildups reported from different palaeocontinents during the onset of the Mulde positive carbon isotope excursion. We have investigated a small aphanitic buildup from the Lower Quarried Limestone Member of the Much Wenlock Limestone Formation, exposed at Whitman's Hill (Herefordshire, corresponding to the central part of the Midland Platform (UK. Up to 50% of the rock volume in this buildup consists of mottled micrite. The SEM studies revealed that the micrite is largely detrital and does not show features characteristic of calcareous cyanobacteria or leiolites. The aphanitic character of the buildup is suggested to be controlled by the depositional rate, and the widespread occurrence of matrix-supported reefs in this interval to be driven by a mid-Homerian rapid eustatic transgression.

  7. Influence of Pressure Build-Up Time of Compression Chamber on Improving the Operation Frequency of a Single-Piston Hydraulic Free-Piston Engine

    Directory of Open Access Journals (Sweden)

    Hai-bo Xie

    2013-01-01

    Full Text Available A single-piston hydraulic free-piston engine with a two-cylinder four-stroke diesel engine as its driver is introduced. It takes the free-piston assembly a certain time to move after the pressure in the compression chamber starts to increase. The time difference between the pressure increasing and the piston starting to move is defined as the pressure build-up time. The characteristics of the pressure build-up time and its influence on the performance of the free-piston engine are introduced and analyzed. Based on the basic law of dynamics of the free-piston assembly, the parameters which influence the pressure build-up time are analyzed. And then improvement and optimization are proposed to shorten the pressure build-up time.

  8. SU-E-T-176: Improved Collimator Scattering Factor (Sc) Measurements for Small Fields Using Build-Up Caps in Robotic Radiosurgery.

    Science.gov (United States)

    Lee, S; Tien, C; Curran, B; Sternick, E

    2012-06-01

    The Monte Carlo calculation algorithm in the MultiPlan (Accuray, Palo Alto, CA) treatment planning system used for CyberKnife (Accuray) robotic radiosurgery requires in-air measurements. In this study, results were compared for the impact of build-up caps using a diode detector for small field in-air measurements. Two acrylic caps custom-made for the SFD diode detector (IBA, Germany) of two thicknesses were compared against free-in-air measurements. The 1.5 and 5 cm thicknesses correspond to Dmax and a depth beyond the range of electron contamination, respectively. A Blue Phantom (IBA) was used to position the diode 80 cm SAD. Measurements were made for all 12 fixed cones ranging from 5 to 60 mm. For the 5 mm cone, there is a 15.6% and 20.0% difference in the Sc factor between the 1.5 cm and 5 cm buildup caps, respectively, versus the free-in-air measurement. For the 7.5 mm cone, the difference is 6.3% and 10.4% for the 1.5 cm and 5 cm buildup caps, respectively, versus the free-in-air measurement. While generally decreasing, the Sc factor for either buildup cap does not agree within 2% to free-in-air measurements until the cone used is larger than 40 mm. Overall, the two buildup caps yield similar Sc factors and the differences observed are attributed to electron contamination. The Monte Carlo calculation algorithm used by the CyberKnife planning manual does not refer to any build-up caps. This study has shown that, particularly for small fields, there are large differences in Sc factors measured with and without buildup caps. In general, for fields smaller than 10 mm, build-up caps should be carefully chosen, especially in commissioning data. © 2012 American Association of Physicists in Medicine.

  9. Characterization and quantification of deposit build-up and removal in straw suspension-fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Shafique Bashir, M.

    2012-06-15

    Deposit probe measurements have been conducted in different biomass suspension-fired boilers by using advanced ash deposition probes. Two kinds of ash deposition probes have been used. A horizontal probe that has been developed further, which can register probe temperature, deposit mass uptake, heat uptake and video monitoring. First steps have also been taken for the development of a vertical probe that was employed for ash deposit formation measurements on a boiler furnace wall. In the first series of probe measurements, the influence of straw firing technology (grate and suspension) on ash transformation, deposit formation rate and deposit characteristics has been investigated. Full-scale probe measurements were conducted at a 250 MWth suspension boiler, firing straw and wood in suspension, and the results were compared with measurements conducted at a 105 MWth straw-fired grate boiler. Bulk elemental analysis of fly ashes revealed that fly ash from suspension firing of straw has high contents of Si, K and Ca, while fly ash from straw grate firing was rich in the volatile elements, K, Cl and S. SEM-EDS analysis showed that the fly ash from straw suspension firing consists of three kinds of particles: 1) flake type Si rich particles, 2) molten or partially molten particles (> 20 m) rich in Si, K and Ca with small amounts of Mg, P, and potassium salts on the outer surface, and 3) small particles rich in K, Cl and S (aerosols, between 0.1 and 5 m). At a fuel gas temperature of 650 deg. C, the deposit formation rate is typically from 5 to 30 g/m2/h and at 900 deg. C, the deposit formation rate is typically 20 to 110 g/m2/h. The objective of the second probe measuring series was to investigate the influence of fuel type (straw share in wood), probe exposure time, probe surface temperature (500 deg. C, 550 deg. C and 600 deg C), and fuel gas temperature (600-1050 deg C) on the transient deposit build-up and shedding in a 350 MWth suspension boiler, firing straw and

  10. An Update of Couch Effect on the Attenuation of Megavoltage Radiotherapy Beam and the Variation of Absorbed Dose in the Build-up Region.

    Science.gov (United States)

    Sedaghatian, T; Momennezhad, M; Rasta, S H; Makhdoomi, Y; Abdollahian, S

    2017-09-01

    Fiber carbon is the most common material used in treating couch as it causes less beam attenuation than other materials. Beam attenuation replaces build-up region, reduces skin-sparing effect and causes target volume under dosage. In this study, we aimed to evaluate beam attenuation and variation of build-up region in 550 TxT radiotherapy couch. In this study, we utilized cylindrical PMMA Farmer chamber, DOSE-1 electrometer and set PMMA phantom in isocenter of gantry and the Farmer chamber on the phantom. Afterwards, the gantry rotated 10°, and attenuation was assessed. To measure build-up region, we used Markus chamber, Solid water phantom and DOSE-1 electrometer. Doing so, we set Solid water phantom on isocenter of gantry and placed Markus chamber in it, then we quantified the build-up region at 0° and 180° gantry angels and compared the obtained values. Notable attenuation and build-up region variation were observed in 550 TxT treatment table. The maximum rate of attenuation was 5.95% for 6 MV photon beam, at 5×5 cm2 field size and 130° gantry angle, while the maximum variation was 7 mm for 6 MV photon beam at 10×10 cm2 field size. Fiber carbon caused beam attenuation and variation in the build-up region. Therefore, the application of fiber carbon is recommended for planning radiotherapy to prevent skin side effects and to decrease the risk of cancer recurrence.

  11. Ultrasonic measurement of the effects of adhesive application and power density on the polymerization behavior of core build-up resins.

    Science.gov (United States)

    Sunada, Noriatsu; Ishii, Ryo; Shiratsuchi, Koji; Shimizu, Yusuke; Tsubota, Keishi; Kurokawa, Hiroyasu; Miyazaki, Masashi

    2013-01-01

    To use ultrasonic measurements to monitor the effects of adhesive application and power density on the polymerization behavior of dual-cured core build-up resins. Ultrasonic measurements were carried out using a pulser-receiver, transducers and an oscilloscope. The core build-up resins were mixed, inserted into a transparent mold and then placed onto a sample stage with or without self-etch adhesive. Power densities of 0 (no light irradiation), 200 and 600 mW/cm(2) were used for curing. The transit time through the core build-up resin disk was divided by the specimen thickness to obtain the longitudinal sound velocity (V). Light irradiation of the core build-up resins at a power density of 600 mW/cm(2) caused V values to rise to an initial plateau of 1550-1650 m/s, then to rise rapidly to a second plateau of 2800-3200 m/s. The rate of V increase was slower when the resin cements were light-irradiated and became faster when irradiated at a higher power density. There were no significant differences between the groups with or without adhesive. The polymerization behavior of the core build-up resins was affected by the power density of the curing unit. The influence of adhesive application differed among the core build-up resins tested.

  12. Damage buildup in Ar-ion-irradiated 3 C -SiC at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, J. B.; Bayu Aji, L. B.; Li, T. T.; Shao, L.; Kucheyev, S. O.

    2015-09-14

    Above room temperature, the accumulation of radiation damage in 3C-SiC is strongly influenced by dynamic defect interaction processes and remains poorly understood. Here, we use a combination of ion channeling and transmission electron microscopy to study lattice disorder in 3C-SiC irradiated with 500 keV Ar ions in the temperature range of 25–250 °C. Results reveal sigmoidal damage buildup for all the temperatures studied. For 150 °C and below, the damage level monotonically increases with ion dose up to amorphization. Starting at 200 °C, the shape of damage–depth profiles becomes anomalous, with the damage peak narrowing and moving to larger depths and an additional shoulder forming close to the ion end of range. As a result, damage buildup curves for 200 and 250 °C exhibit an anomalous two-step shape, with a damage saturation stage followed by rapid amorphization above a critical ion dose, suggesting a nucleation-limited amorphization behavior. Despite their complexity, all damage buildup curves are well described by a phenomenological model based on an assumption of a linear dependence of the effective amorphization cross section on ion dose. In contrast to the results of previous studies, 3C-SiC can be amorphized by bombardment with 500 keV Ar ions even at 250 °C with a relatively large dose rate of ~2×1013 cm-2 s-1, revealing a dominant role of defect interaction dynamics at elevated temperatures.

  13. The importance of wave break events for synoptic-scale buildups of Northern Hemisphere zonal available potential energy

    Science.gov (United States)

    Bowley, Kevin; Atallah, Eyad; Gyakum, John

    2017-04-01

    Zonal available potential energy (ZAPE) is an estimate of the amount of potential energy in the atmosphere available for conversion to kinetic energy, providing a good proxy for the overall strength of the general circulation. Previous studies have estimated total hemispheric ZAPE, ZAPE generation, and conversion to kinetic energy, and proposed physical mechanisms to describe the annual ZAPE cycle as well as short term (sub-seasonal to synoptic) APE depletion events. Large, short term modulations of ZAPE have been shown to be associated with impactful weather events in the mid- and high-latitudes, including severe cyclones and high-amplitude ridging and blocking events In this study, we examine the association of significant synoptic time-scale increases in ZAPE with dynamic tropopause wave break events. ZAPE buildup events are determined using a 1979-2011 daily Northern Hemisphere (20˚ -85˚ N) ZAPE climatology calculated from the National Centers for Environmental Prediction (NCEP) Department of Energy (DOE) Reanalysis 2 global reanalysis dataset in an isobaric framework. To diagnose the importance of wave breaks in the troposphere, we objectively identify wave breaks using potential temperature on the dynamic tropopause, identifying and tracking both anti-cyclonic (LC1) and cyclonic (LC2) wave breaks during the 1979-2011 period. Our results indicate that LC1 wave break events in the equatorward jet exit regions appear to play an important role in ZAPE buildup events. The formation of these anti-cyclonic wave break events result in the development of statistically significant warm-core high pressure anomalies in these regions, acting to reduce baroclinic conversions. We will further demonstrate that changes in LC2 wave break activity in the climatological storm track during ZAPE buildup events are indicative of notable changes to the regions of significant cyclone activity, which are occurring in response to shifts and elongations of the jet stream.

  14. On scale and magnitude of pressure build-up induced by large-scale geologic storage of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Q.; Birkholzer, J. T.

    2011-05-01

    The scale and magnitude of pressure perturbation and brine migration induced by geologic carbon sequestration is discussed assuming a full-scale deployment scenario in which enough CO{sub 2} is captured and stored to make relevant contributions to global climate change mitigation. In this scenario, the volumetric rates and cumulative volumes of CO{sub 2} injection would be comparable to or higher than those related to existing deep-subsurface injection and extraction activities, such as oil production. Large-scale pressure build-up in response to the injection may limit the dynamic storage capacity of suitable formations, because over-pressurization may fracture the caprock, may drive CO{sub 2}/brine leakage through localized pathways, and may cause induced seismicity. On the other hand, laterally extensive sedimentary basins may be less affected by such limitations because (i) local pressure effects are moderated by pressure propagation and brine displacement into regions far away from the CO{sub 2} storage domain; and (ii) diffuse and/or localized brine migration into overlying and underlying formations allows for pressure bleed-off in the vertical direction. A quick analytical estimate of the extent of pressure build-up induced by industrial-scale CO{sub 2} storage projects is presented. Also discussed are pressure perturbation and attenuation effects simulated for two representative sedimentary basins in the USA: the laterally extensive Illinois Basin and the partially compartmentalized southern San Joaquin Basin in California. These studies show that the limiting effect of pressure build-up on dynamic storage capacity is not as significant as suggested by Ehlig-Economides and Economides, who considered closed systems without any attenuation effects.

  15. Modeling of gamma ray energy-absorption buildup factors for thermoluminescent dosimetric materials using multilayer perceptron neural network

    DEFF Research Database (Denmark)

    Kucuk, Nil; Manohara, S.R.; Hanagodimath, S.M.

    2013-01-01

    In this work, multilayered perceptron neural networks (MLPNNs) were presented for the computation of the gamma-ray energy absorption buildup factors (BA) of seven thermoluminescent dosimetric (TLD) materials [LiF, BeO, Na2B4O7, CaSO4, Li2B4O7, KMgF3, Ca3(PO4)2] in the energy region 0.015–15Me...... data for TLD materials have been given with penetration depth and incident photon energy as comparative to the results of the interpolation method using the Geometrical Progression (G-P) fitting formula....

  16. Energy absorption buildup factors of human organs and tissues at energies and penetration depths relevant for radiotherapy and diagnostics

    DEFF Research Database (Denmark)

    Manohara, S. R.; Hanagodimath, S. M.; Gerward, Leif

    2011-01-01

    . With the proper knowledge of buildup factors of human organs and tissues, energy absorption in the human body can be carefully controlled. The present results will help in estimating safe dose levels for radiotherapy patients and also useful in diagnostics and dosimetry. The tissue-equivalent materials...... of human organs and tissues changes significantly with the change of incident photon energy and effective atomic number, Zeff. These changes are due to the dominance of different photon interaction processes in different energy regions and different chemical compositions of human organs and tissues...

  17. Simulation of Electron-Cloud Build-Up for the Cold Arcs of the LHC and Comparison with Measured Data

    CERN Document Server

    Maury Cuna, H; Rumolo, G; Tavian, L; Zimmermann, F

    2011-01-01

    The electron cloud generated by synchrotron radiation or residual gas ionization is a concern for LHC operation and performance. We report the results of simulations studies which examine the electron cloud build-up, at injection energy, 3.5 TeV for various operation parameters. In particular, we determine the value of the secondary emission yield corresponding to the multipacting threshold, and investigate the electron density, and heat as a function of bunch intensity for dipoles and field-free regions. We also include a comparison between simulations results and measured heat-load data from the LHC scrubbing runs in 2011.

  18. Suspension-Firing of Biomass:Part 1, Full-Scale Measurements of Ash Deposit Build-up

    OpenAIRE

    Bashir, Muhammad Shafique; Jensen, Peter Arendt; Frandsen, Flemming; Wedel, Stig; Dam-Johansen, Kim; Wadenbäck, Johan; Pedersen, Søren Thaaning

    2012-01-01

    This paper is Part 1 in a series of two describing probe measurements of deposit build-up and removal (shedding) in a 350 MWth suspension boiler, firing straw and wood. The influence of fuel type (straw share in wood), probe exposure time, probe surface temperature (500, 550, and 600 °C), and flue gas temperature (600–1050 °C) on ash deposit formation rate has been investigated. Investigations of deposit formation rate were made by use of an advanced online deposit probe that allowed nearly c...

  19. Analysis of temperature rise and the use of coolants in the dissipation of ultrasonic heat buildup during post removal.

    Science.gov (United States)

    Davis, Stephen; Gluskin, Alan H; Livingood, Philip M; Chambers, David W

    2010-11-01

    This study was designed to calculate probabilities for tissue injury and to measure effectiveness of various coolant strategies in countering heat buildup produced by dry ultrasonic vibration during post removal. A simulated biological model was used to evaluate the cooling efficacy of a common refrigerant spray, water spray, and air spray in the recovery of post temperatures deep within the root canal space. The data set consisted of cervical and apical measures of temperature increase at 1-second intervals from baseline during continuous ultrasonic instrumentation until a 10 °C increase in temperature at the cervical site was registered, wherein instrumentation ceased, and the teeth were allowed to cool under ambient conditions or with the assistance of 4 coolant methods. Data were analyzed with analysis of variance by using the independent variables of time of ultrasonic application (10, 15, 20 seconds) and cooling method. In addition to the customary means, standard deviations, and analysis of variance tests, analyses were conducted to determine probabilities that procedures would reach or exceed the 10 °C threshold. Both instrumentation time and cooling agent effects were significant at P posts. Cycles of short instrumentation times with active coolants were effective in reducing the probability of tissue damage when teeth were instrumented dry. With as little as 20 seconds of continuous dry ultrasonic instrumentation, the consequences of thermal buildup to an individual tooth might contribute to an injurious clinical outcome. Copyright © 2010 American Association of Endodontists. All rights reserved.

  20. Application of interference microscopy to the study of hologram build-up in LiNbO 3 crystals

    Science.gov (United States)

    Bányász, István; Mandula, Gábor

    2008-09-01

    Interference microscopy was applied to direct microscopic observation of temporal evolution of phase holograms in LiNbO3:Fe photorefractive crystals. First a hologram was recorded in the sample, and diffraction efficiency was monitored during hologram build-up using inactinic laser light. Thus kinetics of hologram build-up could be determined. The initial hologram was erased using white light. Then a series of write-erase cycles were performed with increasing exposure times. Holograms were observed by interference microscope after each exposure. The time elapsed between the exposure and the microscopic observation was negligible compared to the relaxation time of the hologram. The obtained temporal evolution of the grating profile gives a deeper insight into the physical mechanism of hologram formation in photorefractive materials than simple diffraction efficiency measurements. A congruently grown sample of LiNbO3 doped with 10-3 mol/mol Fe in melting was studied by this method. Sample thickness was set to 300 μm to allow correct microscopic observation. Plane-wave holograms were recorded in the samples using an Ar-ion laser at λ = 488.0 nm of grating constants of 3, 6.5 and 8.8 μm.

  1. Quasi in-situ microscopic study of hologram build-up in LiNbO 3 crystals

    Science.gov (United States)

    Bányász, István; Mandula, Gábor

    2007-02-01

    Interference microscopy was applied to direct microscopic observation of temporal evolution of phase holograms in LiNbO 3:Fe photorefractive crystals. First a hologram was recorded in the sample, and diffraction efficiency was monitored during hologram build-up using inactinic laser light. Thus kinetics of hologram build-up could be determined. The initial hologram was erased using white light. Then a series of write-erase cycles were performed with increasing exposure times. Holograms were observed by interference microscope after each exposure. The time elapsed between the exposure and the microscopic observation was negligible compared to the relaxation time of the hologram. The obtained temporal evolution of grating profile gives a deeper insight into the physical mechanism of hologram formation in photorefractive materials than simple diffraction efficiency measurements. A congruently grown sample of LiNbO3 doped with 10-3 mol/mol Fe in melting was studied by the method above. Sample thickness was set to 300 μm to allow correct microscopic observation. Plane-wave holograms were recorded in the samples using an Ar-ion laser at λ = 514 nm of grating constants of 3, 6.5 and 8.8μm.

  2. Development of the DCHAIN-SP code for analyzing decay and build-up characteristics of spallation products

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kosako, Kazuaki

    1999-03-01

    For analyzing the decay and build-up characteristics of spallation products, the DCHAIN-SP code has been developed on the basis of the DCHAIN-2 code by revising the decay data and implementing the neutron cross section data. The decay data are newly processed from the data libraries of EAF 3.1, FENDL/D-1 and ENSDF. The neutron cross section data taken from FENDL/A-2 data library are also prepared to take account of the transmutation of nuclides by the neutron field at the produced position. The DCHAIN-SP code solves the time evolution of decay and build-up of nuclides in every decay chain by the Beteman method. The code can estimate the following physical quantities of produced nuclides: inventory, activity, decay heat by the emission of {alpha}, {beta} and {gamma}-rays, and {gamma}-ray energy spectrum, where the nuclide production rate estimated by the nucleon-meson transport code such as NMTC/JAERI97 is used as an input data. This paper describes about the function, the solution model and the database adopted in the code and explains how to use the code. (author)

  3. Influence of traffic on build-up of polycyclic aromatic hydrocarbons on urban road surfaces: A Bayesian network modelling approach.

    Science.gov (United States)

    Li, Yingxia; Jia, Ziliang; Wijesiri, Buddhi; Song, Ningning; Goonetilleke, Ashantha

    2017-12-04

    Due to their carcinogenic effects, Polycyclic Aromatic Hydrocarbons (PAHs) deposited on urban surfaces are a major concern in the context of stormwater pollution. However, the design of effective pollution mitigation strategies is challenging due to the lack of reliability in stormwater quality modelling outcomes. Current modelling approaches do not adequately replicate the interdependencies between pollutant processes and their influential factors. Using Bayesian Network modelling, this research study characterised the influence of vehicular traffic on the build-up of the sixteen US EPA classified priority PAHs. The predictive analysis was conditional on the structure of the proposed BN, which can be further improved by including more variables. This novel modelling approach facilitated the characterisation of the influence of traffic as a source of origin and also as a key factor that influences the re-distribution of PAHs, with positive or negative relationship between traffic volume and PAH build-up. It was evident that the re-distribution of particle-bound PAHs is determined by the particle size rather than the chemical characteristics such as volatility. Moreover, compared to commercial and residential land uses, mostly industrial land use contributes to the PAHs load released to the environment. Carcinogenic PAHs in industrial areas are likely to be associated with finer particles, while PAHs, which are not classified as human carcinogens, are likely to be found in the coarser particle fraction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Mathematical relationships for metal build-up on urban road surfaces based on traffic and land use characteristics.

    Science.gov (United States)

    Gunawardena, Janaka; Ziyath, Abdul M; Egodawatta, Prasanna; Ayoko, Godwin A; Goonetilleke, Ashantha

    2014-03-01

    The study investigated the influence of traffic and land use parameters on metal build-up on urban road surfaces. Mathematical relationships were developed to predict metals originating from fuel combustion and vehicle wear. The analysis undertaken found that nickel and chromium originate from exhaust emissions, lead, copper and zinc from vehicle wear, cadmium from both exhaust and wear and manganese from geogenic sources. Land use does not demonstrate a clear pattern in relation to the metal build-up process, though its inherent characteristics such as traffic activities exert influence. The equation derived for fuel related metal load has high cross-validated coefficient of determination (Q(2)) and low Standard Error of Cross-Validation (SECV) values which indicates that the model is reliable, while the equation derived for wear-related metal load has low Q(2) and high SECV values suggesting its use only in preliminary investigations. Relative Prediction Error values for both equations are considered to be well within the error limits for a complex system such as an urban road surface. These equations will be beneficial for developing reliable stormwater treatment strategies in urban areas which specifically focus on mitigation of metal pollution. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Effects of salinity build-up on the performance and bacterial community structure of a membrane bioreactor.

    Science.gov (United States)

    Luo, Wenhai; Phan, Hop V; Hai, Faisal I; Price, William E; Guo, Wenshan; Ngo, Hao H; Yamamoto, Kazuo; Nghiem, Long D

    2016-01-01

    This study investigated the effects of salinity increase on bacterial community structure in a membrane bioreactor (MBR) for wastewater treatment. The influent salt loading was increased gradually to simulate salinity build-up in the bioreactor during the operation of a high retention-membrane bioreactor (HR-MBR). Bacterial community diversity and structure were analyzed using 454 pyrosequencing of 16S rRNA genes of MBR mixed liquor samples. Results show that salinity increase reduced biological performance but did not affect microbial diversity in the bioreactor. Unweighted UniFrac and taxonomic analyses were conducted to relate the reduced biological performance to the change of bacterial community structure. In response to the elevated salinity condition, the succession of halophobic bacteria by halotolerant/halophilic microbes occurred and thereby the biological performance of MBR was recovered. These results suggest that salinity build-up during HR-MBR operation could be managed by allowing for the proliferation of halotolerant/halophilic bacteria. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  6. The global build-up to intrinsic ELM bursts seen in divertor full flux loops in Jet

    CERN Document Server

    Chapman, S C; Todd, T N; Watkins, N W; Calderon, F A; Morris, J; Contributors, JET

    2015-01-01

    A global signature of the build-up to an intrinsic ELM is found in the phase of signals measured in full flux azimuthal loops in the divertor region of JET. Full flux loop signals provide a global measurement proportional to the voltage induced by changes in poloidal magnetic flux; they are electromagnetically induced by the dynamics of spatially integrated current density. We perform direct time-domain analysis of the high time-resolution full flux loop signals VLD2 and VLD3. We analyze plasmas where a steady H-mode is sustained over several seconds, during which all the observed ELMs are intrinsic; there is no deliberate intent to pace the ELMing process by external means. ELM occurrence times are determined from the Be II emission at the divertor. We previously found that the occurrence times of intrinsic ELMs correlate with specific phases of the VLD2 and VLD3 signals. Here, we investigate how the VLD2 and VLD3 phases vary with time in advance of the ELM occurrence time. We identify a build-up to the ELM ...

  7. Energy absorption and exposure buildup factors for some polymers and tissue substitute materials: photon energy, penetration depth and chemical composition dependence.

    Science.gov (United States)

    Kurudirek, Murat; Özdemir, Yüksel

    2011-03-01

    The gamma ray energy absorption and exposure buildup factors have been calculated by using the five parameter geometric progression (GP) fitting formula for some polymers and tissue substitute materials in the energy region 0.015-15 MeV up to a penetration depth of 40 mean free paths. From the results, it is worth noting that significant variations occur in gamma ray buildup factors for the given polymers and tissue substitute materials depending on photon energy, penetration depth and chemical composition of the materials. Also, it was observed that there are significant variations between energy absorption (EABF) and exposure (EBF) buildup factors which may be due to the variations in chemical composition of the materials used. Finally, it is expected that the presented buildup factor data may be helpful in (a) estimating the effective dose to be given to patients in radiation therapy and diagnostics, hence allowing corrections to be made to the intensity of radiation, as it is somewhat problematic to evaluate the real absorbed dose in critical organs due to the probability of photon buildup somewhere inside the medium; (b) estimating the health hazards arising from the exposure of the human body to radiation, thus it will be helpful in controlling the exposure of the human body to radiation.

  8. Self-adhesive cements as core build-ups for one-stage post-endodontic restorations?

    Science.gov (United States)

    Naumann, M; Sterzenbach, G; Rosentritt, M; Beuer, F; Meyer-Lückel, H; Frankenberger, R

    2011-03-01

    To investigate the load capability of root filled teeth restored with glass fibre posts when the same self-adhesive composite resin cement was used as post cement and core build-up material. Human maxillary central incisors were divided into four groups (n=10). Teeth were root filled, decoronated and restored using glass fibre posts luted with different cements and composite resins for core build-up (i) RelyX Unicem/Clearfil Core (RXU/CC), (ii) RelyX Unicem/ RelyX Unicem (RXU/RXU), (iii) RelyX Unicem/LuxaCore-Dual (RXU/LCD) and (iv) LuxaCore-Dual/Clearfil (LCD/CC). A 2-mm ferrule crown preparation was always performed. All specimens were restored with adhesively luted all-ceramic crowns and were exposed to thermal cycling and mechanical loading (TCML) and subsequently statically loaded. For analysis of cycles-to-failure during TCML, log-rank statistics were calculated. The nonparametric Kruskal-Wallis test was applied to study group mean differences. Differences in the frequency of the failure modes between the groups were evaluated by Fisher's exact test. All tests were two-sided (α=0.05). Three specimens of RXU/LCD and two of RXU/RXU and LCD/CC, respectively, failed during TCML (P=0.379). For these specimens, the load capability value was set at 0 N. The median fracture load values (min/max) in (N) were RXU/CC=294 (209/445), RXU/RXU = 166 (0/726), RXU/LCD=241 (0/289) and LCD/CC=200 (0/371) (P=0.091). The RXU/CC had the highest (80%) and RXU/LCD the lowest (20%) percentage of restorable failures (P=0.028). These results imply that self-adhesive composite achieved similar load capabilities when used as core build-up materials in root filled teeth restored with glass fibre posts and all-ceramic crowns. © 2010 International Endodontic Journal.

  9. Endodontic treatment and esthetic management of a primary double tooth with direct composite using silicone buildup guide

    Directory of Open Access Journals (Sweden)

    Vinaya Kumar Kulkarni

    2012-01-01

    Full Text Available Gemination and fusion are morphological dental anomalies, characterized by the formation of a clinically wide tooth. Gemination occurs when one tooth bud tries to divide, while fusion occurs if two buds unite. The terms double teeth, double formation, conjoined teeth, geminifusion, vicinifusion and dental twinning are often used to describe fusion and gemination. Double teeth are associated with clinical problems such as poor esthetics, spacing problems and caries susceptibility. Management of such cases requires a comprehensive knowledge of the clinical entity as well as the problems associated with it. This report presents a case of primary double tooth in a 6-year-old boy involving maxillary left central incisor. The anomalous tooth was carious and pulpally involved. This was treated conservatively by endodontic treatment and esthetic rehabilitation was done with direct composite restoration using a silicone buildup guide. The treated tooth was followed up until exfoliation.

  10. Endodontic treatment and esthetic management of a primary double tooth with direct composite using silicone buildup guide.

    Science.gov (United States)

    Kulkarni, Vinaya Kumar; Ragavendra, T Raju; Deshmukh, Jeevanand; Vanka, Amit; Duddu, Mahesh Kumar; Patil, Anand Kumar G

    2012-04-01

    Gemination and fusion are morphological dental anomalies, characterized by the formation of a clinically wide tooth. Gemination occurs when one tooth bud tries to divide, while fusion occurs if two buds unite. The terms double teeth, double formation, conjoined teeth, geminifusion, vicinifusion and dental twinning are often used to describe fusion and gemination. Double teeth are associated with clinical problems such as poor esthetics, spacing problems and caries susceptibility. Management of such cases requires a comprehensive knowledge of the clinical entity as well as the problems associated with it. This report presents a case of primary double tooth in a 6-year-old boy involving maxillary left central incisor. The anomalous tooth was carious and pulpally involved. This was treated conservatively by endodontic treatment and esthetic rehabilitation was done with direct composite restoration using a silicone buildup guide. The treated tooth was followed up until exfoliation.

  11. A 4-year clinical evaluation of direct composite build-ups for space closure after orthodontic treatment.

    Science.gov (United States)

    Demirci, Mustafa; Tuncer, Safa; Öztaş, Evren; Tekçe, Neslihan; Uysal, Ömer

    2015-12-01

    To evaluate the medium-term clinical performance of direct composite build-ups for diastema closures and teeth recontouring using a nano and a nanohybrid composite in combination with three- or two-step etch-and-rinse adhesives following treatment with fixed orthodontic appliances. A total of 30 patients (mean age, 19.5 years) received 147 direct composite additions for teeth recontouring and diastema closures. A nano and a nanohybrid composite (Filtek Supreme XT and CeramX Duo) were bonded to tooth structure by using a three-step (Scotchbond Multipurpose) or a two-step (XP Bond) etch and rinse adhesive. Ten out of 147 composite build-ups (composite addition) constituted tooth recontouring cases, and the remaining 137 constituted diastema closure cases. The restorations were evaluated by two experienced, calibrated examiners according to modified Ryge criteria at the following time intervals: baseline, 1, 2, 3, and 4 years. The 4-year survival rates were 92.8 % for Filtek Supreme XT/Scotchbond Multi-Purpose Plus and 93 % for CeramX Duo/XP Bond. Only ten restorations failed (5 Filtek Supreme XT and 5 CeramX Duo). Statistical analysis revealed no significant differences between the two composite-adhesive combinations with respect to color match, marginal discoloration, wear/loss of anatomical form, caries formation, marginal adaptation, and surface texture on comparing the five time periods (baseline, 1, 2, 3, and 4 years) The 4-year survival rates in the present study were favorable. The restorations exhibited excellent scores with regard to color match, marginal adaptation, surface texture, marginal discoloration, wear/loss of anatomical form, and caries formation, after 4 years of clinical evaluation. Clinical relevance An alternative clinical approach for correcting discrepancies in tooth size and form, such as performing direct composite restorations following fixed orthodontic treatment, may be an excellent and minimally invasive treatment.

  12. The rudist buildup depositional model, reservoir architecture and development strategy of the cretaceous Sarvak formation of Southwest Iran

    Directory of Open Access Journals (Sweden)

    Yang Du

    2015-03-01

    Full Text Available This paper studies the lithofacies, sedimentary facies, depositional models and reservoir architecture of the rudist-bearing Sar-3 zone of Cretaceous Sarvak in the Southwest of Iran by utilizing coring, thin section, XRD data of five coring wells and 3D seismic data. Research results include the following: According to lithofacies features and their association, the rudist-mound and tidal flat are the main microfacies in the Sar-3 depositional time. By investigating the regional tectonic setting and seismic interpretation, a depositional model was built for the Sar-3 zone, which highlights four key points: 1 The distribution of the rudist-buildup is controlled by the paleo-high. 2 The build-up outside of the wide colonize stage but reached the wave-base level in a short time by regression and formation uplift, and was destroyed by the high energy current, then forming the moundy allochthonous deposition after being dispersed and redeposited. 3 The tidal flat develops widely in the upper Sar-3, and the deposition thickness depends on the paleo-structure. The tidal channel develops in the valley and fringe of the Paleo-structure. 4 The exposure within the leaching effect by the meteoric water of the top of Sar-3 is the main controlling factor of the reservoir vertical architecture. The Sar-3 zone featured as the dualistic architecture consists of two regions: the lower is the rudist reef limestone reservoir and the upper is the tidal condense limestone interlayer. The thickness of each is controlled by the paleo-structure. The Paleo-high zone is the preferential development zone. Based on reservoir characteristics of the different zones, a targeted development strategy has been proposed. Keeping the trajectory in the middle of the oil-layer in the paleo-high, and in the paleo-low, make the trajectory crossing the oil-zone and then keep it in the lower.

  13. Effects of salinity build-up on biomass characteristics and trace organic chemical removal: implications on the development of high retention membrane bioreactors.

    Science.gov (United States)

    Luo, Wenhai; Hai, Faisal I; Kang, Jinguo; Price, William E; Guo, Wenshan; Ngo, Hao H; Yamamoto, Kazuo; Nghiem, Long D

    2015-02-01

    This study investigated the impact of salinity build-up on the performance of membrane bioreactor (MBR), specifically in terms of the removal and fate of trace organic chemicals (TrOCs), nutrient removal, and biomass characteristics. Stepwise increase of the influent salinity, simulating salinity build-up in high retention MBRs, adversely affected the metabolic activity in the bioreactor, thereby reducing organic and nutrient removal. The removal of hydrophilic TrOCs by MBR decreased due to salinity build-up. By contrast, with the exception of 17α-ethynylestradiol, the removal of all hydrophobic TrOCs was not affected at high salinity. Moreover, salinity build-up had negligible impact on the residual accumulation of TrOCs in the sludge phase except for a few hydrophilic compounds. Additionally, the response of the biomass to salinity stress also dramatically enhanced the release of both soluble microbial products (SMP) and extracellular polymeric substances (EPS), leading to severe membrane fouling. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  14. Buildup and breakdown of echo suppression for stimuli presented over headphones-the effects of interaural time and level differences.

    Science.gov (United States)

    Krumbholz, Katrin; Nobbe, Andrea

    2002-08-01

    The current study investigates buildup and breakdown of echo suppression for stimuli presented over headphones. The stimuli consisted of pairs of 120-micros clicks. The leading click (lead) and the lagging click (lag) in each pair were lateralized on opposite sides of the midline by means of interaural level differences (ILDs) of +/-10 dB or interaural time differences (ITDs) of +/-300 micros. Echo threshold was measured with an adaptive one-interval, two-alternative, forced-choice procedure with a subjective decision criterion, in which listeners had to report whether they heard a single, fused auditory event on one side of the midline, or two separate events on both sides. In the control conditions, referred to as the "single" conditions, echo threshold was measured for a single click pair, the test pair, presented in isolation. In addition to the control conditions, two kinds of test conditions were investigated, in which the test pair was preceded by 12 identical conditioning pairs: in the "same" conditions, the interaural configuration (ILDs or ITDs) of the conditioning pairs was identical to that of the test pair; in the "switch" conditions, the interaural configuration of lead and lag was reversed between the conditioning pairs and the test pair, in order to produce a switch in the lateralizations of the stimuli between the conditioning train and the test pair. No matter whether the lateralization of the clicks was produced by ILDs or by ITDs, most listeners experienced a buildup of echo suppression in the "same" conditions, manifested by a prolongation of echo threshold relative to the respective "single" conditions. However, the breakdown of echo suppression was much stronger in the ILD-switch than in the ITD-switch conditions. In five out of six listeners, the ITD switch had hardly any effect on echo threshold, although the ITDs (+/-300 micros) produced roughly the same degree of lateral displacement as the ILDs (+/-10 dB). These results suggest that the

  15. Acetone as biomarker for ketosis buildup capability--a study in healthy individuals under combined high fat and starvation diets.

    Science.gov (United States)

    Prabhakar, Amlendu; Quach, Ashley; Zhang, Haojiong; Terrera, Mirna; Jackemeyer, David; Xian, Xiaojun; Tsow, Francis; Tao, Nongjian; Forzani, Erica S

    2015-04-22

    Ketogenic diets are high fat and low carbohydrate or very low carbohydrate diets, which render high production of ketones upon consumption known as nutritional ketosis (NK). Ketosis is also produced during fasting periods, which is known as fasting ketosis (FK). Recently, the combinations of NK and FK, as well as NK alone, have been used as resources for weight loss management and treatment of epilepsy. A crossover study design was applied to 11 healthy individuals, who maintained moderately sedentary lifestyle, and consumed three types of diet randomly assigned over a three-week period. All participants completed the diets in a randomized and counterbalanced fashion. Each weekly diet protocol included three phases: Phase 1 - A mixed diet with ratio of fat: (carbohydrate + protein) by mass of 0.18 or the equivalence of 29% energy from fat from Day 1 to Day 5. Phase 2- A mixed or a high-fat diet with ratio of fat: (carbohydrate + protein) by mass of approximately 0.18, 1.63, or 3.80 on Day 6 or the equivalence of 29%, 79%, or 90% energy from fat, respectively. Phase 3 - A fasting diet with no calorie intake on Day 7. Caloric intake from diets on Day 1 to Day 6 was equal to each individual's energy expenditure. On Day 7, ketone buildup from FK was measured. A statistically significant effect of Phase 2 (Day 6) diet was found on FK of Day 7, as indicated by repeated analysis of variance (ANOVA), F(2,20) = 6.73, p diets with 79% fat content and 90% fat content vs. 29% fat content (with p = 0.00159**, and 0.04435**, respectively), with no significant difference between diets with 79% fat content and 90% fat content. In addition, independent of the diet, a significantly higher ketone buildup capability of subjects with higher resting energy expenditure (R(2) = 0.92), and lower body mass index (R(2) = 0.71) was observed during FK.

  16. Effect of various physical parameters on surface and build-up dose for 15-MV X-rays

    Science.gov (United States)

    Yadav, Girigesh; Yadav, R. S.; Kumar, Alok

    2010-01-01

    The purpose of this study was to find out the effect of various physical parameters on the skin and build-up doses of 15-MV photon beams. The effects of field dimensions, acrylic shadow tray, focus to-skin distance (FSD) on surface and buildup dose were determined for open, motorized 60° wedge (MW) and blocked fields. A ‘Markus’ plane parallel plate chamber was used for these measurements in an Elekta (6–15MV) linear accelerator. The surface dose for MW fields was lower than the dose for an open field, but the trend reversed for large fields and higher degree wedges. With the use of an acrylic shadow tray, the surface dose increased for all field sizes, but the increase was dominant for large fields. The surface dose for blocked fields was lower than the dose for open fields. The percentage depth dose of 10 × 10 cm2 field at surface (PDD0) for open beam were 13.89%, 11.71%, and 10.74% at 80 cm, 100 cm, and 120 cm FSD, respectively. The blocking tray increased PDD0 of 10 × 10 cm2 field to 26.29%, 14.01%, and 11.53%, while the motorized 60° wedge decreased PDD0 to 11.32%, 9.7%, and 8.9 % at these FSDs. The maximum PDD difference seen at surface (i.e., skin) for 5 × 5 cm2, 15 × 15 cm2, and 30 × 30 cm2 are 0.5%, 4.6%, and 5.6% for open field and 0.9%, 4.7%, and 7.2% for motorized 60° wedge field, when FSDs varied from 80 cm to 120 cm. The maximum PDD difference seen at surface for 5 × 5 cm2, 15 × 15 cm2, and 30 × 30 cm2 fields are 5.6%, 22.8%, and 29.6%, respectively, for a 1.0-cm perspex-blocking tray as the FSD is changed. The maximum PDD difference was seen at the surface (i.e., skin) and this decreased with increasing depth. PMID:21170184

  17. DC Model Cable under Polarity Inversion and Thermal Gradient: Build-Up of Design-Related Space Charge

    Directory of Open Access Journals (Sweden)

    Nugroho Adi

    2017-07-01

    Full Text Available In the field of energy transport, High-Voltage DC (HVDC technologies are booming at present due to the more flexible power converter solutions along with needs to bring electrical energy from distributed production areas to consumption sites and to strengthen large-scale energy networks. These developments go with challenges in qualifying insulating materials embedded in those systems and in the design of insulations relying on stress distribution. Our purpose in this communication is to illustrate how far the field distribution in DC insulation systems can be anticipated based on conductivity data gathered as a function of temperature and electric field. Transient currents and conductivity estimates as a function of temperature and field were recorded on miniaturized HVDC power cables with construction of 1.5 mm thick crosslinked polyethylene (XLPE insulation. Outputs of the conductivity model are compared to measured field distributions using space charge measurements techniques. It is shown that some features of the field distribution on model cables put under thermal gradient can be anticipated based on conductivity data. However, space charge build-up can induce substantial electric field strengthening when materials are not well controlled.

  18. Recurrence interval of the 2008 Mw 7.9 Wenchuan earthquake inferred from geodynamic modelling stress buildup and release

    Science.gov (United States)

    Liu, Chang; Dong, Peiyu; Shi, Yaolin

    2017-10-01

    The destructive 2008 Mw 7.9 Wenchuan earthquake ruptured the Longmen Shan (LMS) fault zone and devastated cities in Sichuan province, China. Estimates of the recurrence interval of the large earthquake is important to understand the feature of seismic activity and to analyze the seismic hazard in the fault area. In this research we introduce the method of geodynamic modelling to estimate the recurrence interval of the Mw7.9 earthquake based on the basic physics of earthquakes-stress buildup and release on fault. The inter-seismic stress accumulation prior to the 2008 Wenchuan earthquake is extracted from our previous study, which developed 3D finite element visco-elastic lithospheric model of the LMS fault zone. The co-seismic stress release and the post-seismic stress relaxation of the earthquake are simulated through dislocation source models. The recurrence interval, which is the duration needed to accumulate the magnitude of the stress drop of the Mw7.9 earthquake, is estimated to be about 4200-6500 years. Sensitivities of the estimated recurrence interval relying on model dependent parameters, such as the viscosity and slip models, are discussed. This research provides a preferred method to estimate recurrence interval of large earthquake in fault zone.

  19. Post and core build-ups in crown and bridge abutments: Bio-mechanical advantages and disadvantages.

    Science.gov (United States)

    Mamoun, John

    2017-06-01

    Dentists often place post and core buildups on endodontically treated abutments for crown and bridge restorations. This article analyzes the bio-mechanical purposes, advantages and disadvantages of placing a core or a post and core in an endodontically treated tooth and reviews literature on post and core biomechanics. The author assesses the scientific rationale of the claim that the main purpose of a post is to retain a core, or the claim that posts weaken teeth. More likely, the main function of a post is to help prevent the abutment, on which a crown is cemented, from fracturing such that the abutment separates from the tooth root, at a fracture plane that is located approximately and theoretically at the level of the crown (or ferrule) margin. A post essentially improves the ferrule effect that is provided by the partial fixed denture prosthesis. This paper also explores the difference between bio-mechanical failures of crowns caused by lack of retention or excess taper, versus failures due to a sub-optimal ferrule effect in crown and bridge prostheses.

  20. Determination of neutron buildup factor using analytical solution of one-dimensional neutron diffusion equation in cylindrical geometry

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Julio Cesar L.; Vilhena, Marco Tullio, E-mail: julio.lombaldo@ufrgs.b, E-mail: vilhena@pq.cnpq.b [Universidade Federal do Rio Grande do Sul (DMPA/UFRGS), Porto Alegre, RS (Brazil). Dept. de Matematica Pura e Aplicada. Programa de Pos Graduacao em Matematica Aplicada; Borges, Volnei; Bodmann, Bardo Ernest, E-mail: bardo.bodmann@ufrgs.b, E-mail: borges@ufrgs.b [Universidade Federal do Rio Grande do Sul (PROMEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica

    2011-07-01

    The principal idea of this work, consist on formulate an analytical method to solved problems for diffusion of neutrons with isotropic scattering in one-dimensional cylindrical geometry. In this area were develop many works that study the same problem in different system of coordinates as well as cartesian system, nevertheless using numerical methods to solve the shielding problem. In view of good results in this works, we starting with the idea that we can represent a source in the origin of the cylindrical system by a Delta Dirac distribution, we describe the physical modeling and solved the neutron diffusion equation inside of cylinder of radius R. For the case of transport equation, the formulation of discrete ordinates S{sub N} consists in discretize the angular variables in N directions and in using a quadrature angular set for approximate the sources of scattering, where the Diffusion equation consist on S{sub 2} approximated transport equation in discrete ordinates. We solved the neutron diffusion equation with an analytical form by the finite Hankel transform. Was presented also the build-up factor for the case that we have neutron flux inside the cylinder. (author)

  1. A closed-form formulation for the build-up factor and absorbed energy for photons and electrons in the Compton energy range in Cartesian geometry

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Volnei; Vilhena, Marco Tullio, E-mail: borges@ufrgs.b, E-mail: vilhena@pq.cnpq.b [Universidade Federal do Rio Grande do Sul (PROMEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica; Fernandes, Julio Cesar Lombaldo, E-mail: julio.lombaldo@ufrgs.b [Universidade Federal do Rio Grande do Sul (DMPA/UFRGS), Porto Alegre, RS (Brazil). Dept. de Matematica Pura e Aplicada. Programa de Pos Graduacao em Matematica Aplicada

    2011-07-01

    In this work, we report on a closed-form formulation for the build-up factor and absorbed energy, in one and two dimensional Cartesian geometry for photons and electrons, in the Compton energy range. For the one-dimensional case we use the LTS{sub N} method, assuming the Klein-Nishina scattering kernel for the determination of the angular radiation intensity for photons. We apply the two-dimensional LTS{sub N} nodal solution for the averaged angular radiation evaluation for the two-dimensional case, using the Klein-Nishina kernel for photons and the Compton kernel for electrons. From the angular radiation intensity we construct a closed-form solution for the build-up factor and evaluate the absorbed energy. We present numerical simulations and comparisons against results from the literature. (author)

  2. Influence of standard RF coil materials on surface and buildup dose from a 6 MV photon beam in magnetic field.

    Science.gov (United States)

    Ghila, A; Fallone, B G; Rathee, S

    2016-11-01

    Magnetic resonance guided teletherapy systems aspire to image the patient concurrently with the radiation delivery. Thus, the radiofrequency (RF) coils used for magnetic resonance imaging, placed on or close to patient skin and in close proximity to the treatment volume, would be irradiated leading to modifications of radiation dose to the skin and in the buildup region. The purpose of this work is to measure and assess these dose modifications due to standard off-the-shelf RF coil materials. A typical surface coil was approximated as layered sheets of polycarbonate, copper tape, and Teflon to emulate the base, conductor, and cover, respectively. A separate investigation used additional coil materials, such as copper pipe, plastic coil housing, a typical coil padding material, and a thin copper conductor. The materials were placed in the path of a 6 MV photon beam at various distances from polystyrene phantoms in which the surface and buildup doses were measured. The experiments were performed on a clinical Varian linac with no magnetic field and with a 0.21 T electromagnet producing a magnetic field parallel to the beam central axis. The authors repeated similar experiments in the presence of a 0.22 T magnetic field oriented perpendicular to the beam central axis using an earlier linac-MR prototype, with a biplanar permanent magnet. The radiation detectors used for the measurements were two different parallel plate ion chambers and GAFChromic films. A typical open beam surface dose of 20% (relative to open beam Dmax) was increased to 63% by the coil padding material and to >74% by all other materials when placed in direct contact with the phantom, irrespective of magnetic field presence or orientation. Without a magnetic field, the surface dose decreased as the test materials were moved away from the phantom surface toward the radiation source, reaching between 30% and 40% at 10 cm gap between the phantom and the test materials. In the presence of the transverse

  3. Catheter for Cleaning Surgical Optics During Surgical Procedures: A Possible Solution for Residue Buildup and Fogging in Video Surgery.

    Science.gov (United States)

    de Abreu, Igor Renato Louro Bruno; Abrão, Fernando Conrado; Silva, Alessandra Rodrigues; Corrêa, Larissa Teresa Cirera; Younes, Riad Nain

    2015-05-01

    Currently, there is a tendency to perform surgical procedures via laparoscopic or thoracoscopic access. However, even with the impressive technological advancement in surgical materials, such as improvement in quality of monitors, light sources, and optical fibers, surgeons have to face simple problems that can greatly hinder surgery by video. One is the formation of "fog" or residue buildup on the lens, causing decreased visibility. Intracavitary techniques for cleaning surgical optics and preventing fog formation have been described; however, some of these techniques employ the use of expensive and complex devices designed solely for this purpose. Moreover, these techniques allow the cleaning of surgical optics when they becomes dirty, which does not prevent the accumulation of residue in the optics. To solve this problem we have designed a device that allows cleaning the optics with no surgical stops and prevents the fogging and residue accumulation. The objective of this study is to evaluate through experimental testing the effectiveness of a simple device that prevents the accumulation of residue and fogging of optics used in surgical procedures performed through thoracoscopic or laparoscopic access. Ex-vivo experiments were performed simulating the conditions of residue presence in surgical optics during a video surgery. The experiment consists in immersing the optics and catheter set connected to the IV line with crystalloid solution in three types of materials: blood, blood plus fat solution, and 200 mL of distilled water and 1 vial of methylene blue. The optics coupled to the device were immersed in 200 mL of each type of residue, repeating each immersion 10 times for each distinct residue for both thirty and zero degrees optics, totaling 420 experiments. A success rate of 98.1% was observed after the experiments, in these cases the device was able to clean and prevent the residue accumulation in the optics.

  4. Effect of self and dual-curing on degree of conversion and crosslink density of dual-cure core build-up materials.

    Science.gov (United States)

    Karakis, Duygu; Yıldırım-Bicer, Arzu Zeynep; Dogan, Arife; Koralay, Haluk; Cavdar, Sukru

    2017-04-01

    Dual-cure core build-up resins have been developed to take advantages of both self and light-cured resin. The aim of present study was to determine the polymerization characteristics of self and dual-cured modes of dual-cure core build-up composites evaluating degree of conversion (DC) and crosslink density by measurement of glass-transition temperature (Tg) and hardness decrease in ethanol. Clearfil Dc Core Automix (CLF) and Grandio Core Dc (GR) core build-up resins were selected. Twelve specimens for both composites were polymerized using quartz-halogen-tungsten light curing unit (QTH) and 12 specimens polymerized chemically. DC was determined by ATR-FTIR spectroscopy. TG/DTA analysis was performed to determine Tg. Microhardness value of specimens was determined by Vickers-tester before and after specimens stored in absolute ethanol for 24h. One-way ANOVA showed no different DC values between dual and self-cured mode of GR and dual-cured CLF composites had higher DC than self-cured mode. Tg and percentage of softening in ethanol values of GR and CLF revealed significant difference between self and dual-cured mode. In comparison of GR and CLF, DC showed no statistical difference in both curing modes. However, dual and self-cured GR has statistically higher Tg values and lower percentage of softening in ethanol than CLF. Polymerization characteristics of dual-cure core build-up composites have superiority in dual-cured mode than self-cured. Copyright © 2016. Published by Elsevier Ltd.

  5. Monte Carlo correction factors for a Farmer 0.6 cm3 ion chamber dose measurement in the build-up region of the 6 MV clinical beam

    Science.gov (United States)

    Pena, J.; Sánchez-Doblado, F.; Capote, R.; Terrón, J. A.; Gómez, F.

    2006-03-01

    Reference dosimetry of photon fields is a well-established subject and currently available protocols (such as the IAEA TRS-398 and AAPM TG-51) provide methods for converting the ionization chamber (IC) reading into dose to water, provided reference conditions of charged particle equilibrium (CPE) are fulfilled. But these protocols cannot deal with the build-up region, where the lack of CPE limits the applicability of the cavity theorems and so the chamber correction factors become depth dependent. By explicitly including the IC geometry in the Monte Carlo simulations, depth-dependent dose correction factors are calculated for a PTW 30001 0.6 cm3 ion chamber in the build-up region of the 6 MV photon beam. The corrected percentage depth dose (PDD) agrees within 2% with that measured using the NACP 02 plane-parallel ion chamber in the build-up region at depths greater than 0.4 cm, where the Farmer chamber wall reaches the phantom surface.

  6. Evaluation of the Performance and the Predictive Capacity of Build-Up and Wash-Off Models on Different Temporal Scales

    Directory of Open Access Journals (Sweden)

    Saja Al Ali

    2016-07-01

    Full Text Available Stormwater quality modeling has arisen as a promising tool to develop mitigation strategies. The aim of this paper is to assess the build-up and wash-off processes and investigate the capacity of several water quality models to accurately simulate and predict the temporal variability of suspended solids concentrations in runoff, based on a long-term data set. A Markov Chain Monte-Carlo (MCMC technique is applied to calibrate the models and analyze the parameter’s uncertainty. The short-term predictive capacity of the models is assessed based on inter- and intra-event approaches. Results suggest that the performance of the wash-off model is related to the dynamic of pollutant transport where the best fit is recorded for first flush events. Assessment of SWMM (Storm Water Management Model exponential build-up model reveals that better performance is obtained on short periods and that build-up models relying only on the antecedent dry weather period as an explanatory variable, cannot predict satisfactorily the accumulated mass on the surface. The predictive inter-event capacity of SWMM exponential model proves its inability to predict the pollutograph while the intra-event approach based on data assimilation proves its efficiency for first flush events only. This method is very interesting for management practices because of its simplicity and easy implementation.

  7. Measurement of air kerma rates for 6- to 7-MeV high-energy gamma-ray field by ionisation chamber and build-up plate.

    Science.gov (United States)

    Kowatari, Munehiko; Tanimura, Yoshihiko; Tsutsumi, Masahiro

    2014-12-01

    The 6- to 7-MeV high-energy gamma-ray calibration field by the (19)F(p, αγ)(16)O reaction is to be served at the Japan Atomic Energy Agency. For the determination of air kerma rates using an ionisation chamber in the 6- to 7-MeV high-energy gamma-ray field, the establishment of the charged particle equilibrium must be achieved during measurement. In addition to measurement of air kerma rates by the ionisation chamber with a thick build-up cap, measurement using the ionisation chamber and a build-up plate (BUP) was attempted, in order to directly determine air kerma rates under the condition of regular calibration for ordinary survey meters and personal dosemeters. Before measurements, Monte Carlo calculations were made to find the optimum arrangement of BUP in front of the ionisation chamber so that the charged particle equilibrium could be well established. Measured results imply that air kerma rates for the 6- to 7-MeV high-energy gamma-ray field could be directly determined under the appropriate condition using an ionisation chamber coupled with build-up materials. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Comparative evaluation of shear bond strength of three resin based dual-cure core build-up materials: An In-vitro study.

    Science.gov (United States)

    Jain, Gaurav; Narad, Aditi; Boruah, Lalit C; Rajkumar, Balakrishnan

    2015-01-01

    The in-vitro study compared the shear bond strength (SBS) of three recently introduced dual-cure resin based core build-up materials namely ParaCore, FluoroCore, and MultiCore. One hundred twenty extracted permanent human mandibular molar teeth were taken and sectioned horizontally beneath the dentinoenamel junction to expose the coronal dentin. The specimens obtained were divided into three main groups based on the materials used and then further divided into four sub-groups based on time interval with ten samples each. The dentin surface was treated with the respective adhesives of the groups and then bulk filled with core build-up materials. The attained samples were than subjected to shear loading in Instron Universal Testing Machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA), Tukey's HSD, and Levene's test. The mean SBS was highest in MultiCore at all time periods as compared to FluoroCore and ParaCore and was also higher at 48 h thermocycling in all three groups studied. MultiCore dual-cure resin based core build-up material showed the highest mean SBS as compared to FluoroCore and ParaCore. SBS was not negatively affected by thermocycling.

  9. Determination of effective atomic numbers, effective electrons numbers, total atomic cross-sections and buildup factor of some compounds for different radiation sources

    Science.gov (United States)

    Levet, A.; Özdemir, Y.

    2017-01-01

    The photon interaction parameters such as mass attenuation coefficient, effective atomic number, effective electron density, buildup factor have been measured for Fe(NO3)3, V4O2, NaCO3·H2O, C6H5FeO7·H2O and CuCI compounds using 137Ba, 157Gd and 241Am γ-rays sources in stable geometry. The mass attenuation coefficients have been determined experimentally via Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF) system and theoretically by using WinXCom computer program. Then, effective atomic numbers, Zeff, and electron densities, Neff, have been calculated by using the mass attenuation coefficients. The obtained values of effective atomic numbers have been compared with the ones calculated according to a different approach proposed by Hine and the calculated ones from theory. Also, photon buildup factors were obtained by changing collimator diameters in the different photon energies. We observed that the buildup factor increased as the collimator diameter increased for all sources used.

  10. Mississippian carbonate buildups and development of cool-waterlike carbonate platforms in the Illinois Basin, Midcontinent U.S.A.

    Science.gov (United States)

    Lasemi, Z.; Norby, R.D.; Utgaard, J.E.; Ferry, W.R.; Cuffey, R.J.; Dever, G.R.

    2005-01-01

    Numerous biohermal buildups occur in Mississippian (Lower Carboniferous) strata in the Illinois Basin and adjacent regions. They developed as mud mounds, biodetrital calcisiltite mounds, and bryozoan frame thickets (fenestrate-frame coquina or rudstone) during the Kinderhookian and early Meramecian (Tournaisian and early Visean), and as microbial mud mounds, microbial- serpulidbryozoanboundstones, and solenoporoid (red algal) boundstones during the Chesterian (late Visean and Serpukhovian). True Waulsortian mounds did not develop in the Illinois Basin, but echinoderm (primarily crinoids)-bryozoan carbonate banks and bryozoan frame thickets generally occupied the same niche during the Kinderhookian-early Meramecian. Nutrient availability and the resulting increase in the productivity of echinoderms and bryozoans were apparently detrimental to Waulsortian mound development. Deposition of crinoidal-bryozoan carbonates during the Kinderhookian-Osagean initially occurred on a ramp setting that later evolved into a platform with a relatively steep margin through sediment aggradation and progradation. By mid-Osagean-early Meramecian, two such platforms, namely the Burlington Shelf and the Ullin Platform, developed adjacent to a deep, initially starved basin. Sedimentologic and petrographic characteristics of the Kinderhookian-earliest Meramecian carbonates resemble the modern cool-water Heterozoan Association. This is in contrast with post-earliest Meramecian carbonates, which are typically oolitic and peloidal with common peri tidal facies. The post-earliest Meramecian carbonates, therefore, resemble those of the warm-water Photozoan Association. The prevalence of Heterozoan carbonates in the Illinois Basin correlates with a rapid increase in the rate of subsidence and a major second-order eustatic sea-level rise that resulted in deep-water starved basins at this time. In the starved Illinois Basin, deposition was initially limited to a thin phosphatic shale that was

  11. Fracture Resistance of Endodontically Treated Teeth Restored with 2 Different Fiber-reinforced Composite and 2 Conventional Composite Resin Core Buildup Materials: An In Vitro Study.

    Science.gov (United States)

    Eapen, Ashly Mary; Amirtharaj, L Vijay; Sanjeev, Kavitha; Mahalaxmi, Sekar

    2017-09-01

    The purpose of this in vitro study was to comparatively evaluate the fracture resistance of endodontically treated teeth restored with 2 fiber-reinforced composite resins and 2 conventional composite resin core buildup materials. Sixty noncarious unrestored human maxillary premolars were collected, endodontically treated (except group 1, negative control), and randomly divided into 5 groups (n = 10). Group 2 was the positive control. The remaining 40 prepared teeth were restored with various direct core buildup materials as follows: group 3 teeth were restored with dual-cure composite resin, group 4 with posterior composite resin, group 5 with fiber-reinforced composite resin, and group 6 with short fiber-reinforced composite resin. Fracture strength testing was performed using a universal testing machine. The results were statistically analyzed by 1-way analysis of variance and the post hoc Tukey test. Fracture patterns for each sample were also examined under a light microscope to determine the level of fractures. The mean fracture resistance values (in newtons) were obtained as group 1 > group 6 > group 4 > group 3 > group 5 > group 2. Group 6 showed the highest mean fracture resistance value, which was significantly higher than the other experimental groups, and all the fractures occurred at the level of enamel. Within the limitations of this study, a short fiber-reinforced composite can be used as a direct core buildup material that can effectively resist heavy occlusal forces against fracture and may reinforce the remaining tooth structure in endodontically treated teeth. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Damage of lithium-disilicate all-ceramic restorations by an experimental self-adhesive resin cement used as core build-ups.

    Science.gov (United States)

    Sterzenbach, G; Karajouli, G; Tunjan, R; Spintig, T; Bitter, K; Naumann, M

    2015-03-01

    This in vitro study aimed to predict the potential of fracture initiation after long-term incubation (LTI) of lithium-disilicate restorations due to a hygroscopic expansion of self-adhesive resin cement (SARC) used as core build-up material. Human maxillary central incisors were divided into four groups (n = 10). Teeth were endodontically treated and decoronated. Specimens were restored in a one-stage post-and-core procedure using experimental dual-curing SARC. Three application protocols to build up the core were compared as follows: I, auto-polymerisation; II, dual curing including 40 s light-initiated polymerisation; and III, an open matrix technique in a dual-curing mode. In group IV, a chemical-curing composite core build-up material served as control. For all specimens, a 2-mm ferrule design was ensured. Full anatomic lithium-disilicate crowns were adhesively luted. One-year LTI in 0.5 % chloramine solution at 37 °C was performed. Restorations were examined after 3, 6, 9 and 12 month of storage. Survival rates were calculated using log-rank statistics (p = 0.05). Fifty per cent of lithium-disilicate crowns of groups I and II showed visible crack propagation after 9 months of incubation, while one crown failed in group III. No failure was observed in group IV. The survival rates differed significantly (p = 0.017). SARC used to build up the core of severely damaged endodontically treated teeth does have the potential to cause fracture of lithium-disilicate crown restorations. Hygroscopic expansion of self-adhesive resin cements used as a core build-up material might have an adverse impact on longevity of glass-ceramic crowns.

  13. Build-up and wash-off dynamics of atmospherically derived Cu, Pb, Zn and TSS in stormwater runoff as a function of meteorological characteristics.

    Science.gov (United States)

    Murphy, Louise U; Cochrane, Thomas A; O'Sullivan, Aisling

    2015-03-01

    Atmospheric pollutants deposited on impermeable surfaces can be an important source of pollutants to stormwater runoff; however, modelling atmospheric pollutant loads in runoff has rarely been done, because of the challenges and uncertainties in monitoring their contribution. To overcome this, impermeable concrete boards (≈ 1m(2)) were deployed for 11 months in different locations within an urban area (industrial, residential and airside) throughout Christchurch, New Zealand, to capture spatially distributed atmospheric deposition loads in runoff over varying meteorological conditions. Runoff was analysed for total and dissolved Cu, Zn, Pb, and total suspended solids (TSS). Mixed-effect regression models were developed to simulate atmospheric pollutant loads in stormwater runoff. In addition, the models were used to explain the influence of different meteorological characteristics (e.g. antecedent dry days and rain depth) on pollutant build-up and wash-off dynamics. The models predicted approximately 53% to 69% of the variation in pollutant loads and were successful in predicting pollutant-load trends over time which can be useful for general stormwater planning processes. Results from the models illustrated the importance of antecedent dry days on pollutant build-up. Furthermore, results indicated that peak rainfall intensity and rain duration had a significant relationship with TSS and total Pb, whereas, rain depth had a significant relationship with total Cu and total Zn. This suggested that the pollutant speciation phase plays an important role in surface wash-off. Rain intensity and duration had a greater influence when the pollutants were predominantly in their particulate phase. Conversely, rain depth exerted a greater influence when a high fraction of the pollutants were predominantly in their dissolved phase. For all pollutants, the models were represented by a log-arctan relationship for pollutant build-up and a log-log relationship for pollutant wash

  14. Together, slowly but surely: the role of social interaction and feedback in the build-up of benefit in collective decision-making

    DEFF Research Database (Denmark)

    Bahrami, Bahador; Olsen, Karsten; Bang, Dan

    2011-01-01

    in a significant collective benefit in perceptual decisions. When feedback was not available a collective benefit was not initially obtained but emerged through practice to the extent that in the second half of the experiments, collective benefits obtained with (Experiment 1) and without (Experiment 2) feedback...... were robust and statistically indistinguishable. Taken together, this work demonstrates that social interaction was necessary for build-up of reliable collaborative benefit, whereas objective reference only accelerated the process but-given enough opportunity for practice-was not necessary for building...

  15. A Comprehensive Study on Gamma-Ray Exposure Build-Up Factors and Fast Neutron Removal Cross Sections of Fly-Ash Bricks

    Directory of Open Access Journals (Sweden)

    Vishwanath P. Singh

    2013-01-01

    Full Text Available Geometric progression (GP method was utilized to investigate gamma-ray exposure build-up factors of fly-ash bricks for energies from 0.015 to 15 MeV up to 40 mfp penetration depth. The EBFs of the fly-ash bricks are dependent upon the photon energy, penetration depths, and the chemical compositions of the elements. Appreciable variations in exposure build-up factor (EBF are noted for the fly-ash bricks. The EBFs were found to be small in low and high photon energy regions whereas very large in medium energy region. EBF of the bricks is inversely proportional to equivalent atomic number below 10 mfp for entire energy region of interest 0.015 to 15 MeV. The EBFs of fly-ash, brick of mud, and common brick were similar at 1.5 MeV photon energy. The EBF of the fly-ash bricks was found to be higher than that of the brick of mud, and common brick. The fast neutron removal cross sections of the fly-ash bricks, brick of mud, and common bricks were also calculated which were found to be in the same order. It is expected that this study should be very directly useful for shielding effectiveness of fly-ash brick materials and dose estimation.

  16. Development of a fibre-optic dosemeter to measure the skin dose and percentage depth dose in the build-up region of therapeutic photon beams.

    Science.gov (United States)

    Kim, K-A; Yoo, W J; Jang, K W; Moon, J; Han, K-T; Jeon, D; Park, J-Y; Cha, E-J; Lee, B

    2013-03-01

    In this study, a fibre-optic dosemeter (FOD) using an organic scintillator with a diameter of 0.5 mm for photon-beam therapy dosimetry was fabricated. The fabricated dosemeter has many advantages, including water equivalence, high spatial resolution, remote sensing and real-time measurement. The scintillating light generated from an organic-dosemeter probe embedded in a solid-water stack phantom is guided to a photomultiplier tube and an electrometer via 20 m of plastic optical fibre. Using this FOD, the skin dose and the percentage depth dose in the build-up region according to the depths of a solid-water stack phantom are measured with 6- and 15-MV photon-beam energies with field sizes of 10 × 10 and 20 × 20 cm(2), respectively. The results are compared with those measured using conventional dosimetry films. It is expected that the proposed FOD can be effectively used in radiotherapy dosimetry for accurate measurement of the skin dose and the depth dose distribution in the build-up region due to its high spatial resolution.

  17. Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials.

    Science.gov (United States)

    Sawani, Shefali; Arora, Vipin; Jaiswal, Shikha; Nikhil, Vineeta

    2014-07-01

    Evaluation of microleakage is important for assessing the success of new restorative materials and methods. Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials. Standardized mesi-occlusal (MO) and distoocclusal (DO) Class II tooth preparations were preparedon 53 molars and samples were randomly divided into six experimental groups and one control group for restorations. Group 1: Open-Sandwich technique (OST) with flowable composite at the gingival seat. Group 2: OST with resin-modified glass ionomer cement (RMGIC) at the gingival seat. Group 3: Closed-Sandwich technique (CST) with flowable composite at the pulpal floor and axial wall. Group 4: CST with RMGIC at the pulpal floor and axial wall. Group 5: OST with flowable composite at the pulpal floor, axial wall, and gingival seat. Group 6: OST with RMGIC at the pulpal floor, axial wall, and gingival seat. Group 7: Control - no lining material, centripetal technique only. After restorations and thermocycling, apices were sealed and samples were immersed in 0.5% basic fuchsin dye. Sectioning was followed by stereomicroscopic evaluation. Results were analyzed using Post Hoc Bonferroni test (statistics is not a form of tabulation). Cervical scores of control were more than the exprimental groups (P 0.05). Class II composite restorations with centripetal build-up alone or when placed with CST reduces the cervical microleakage when compared to OST.

  18. Effect of Er:YAG laser pretreatment on bond strength of a composite core build-up material to fiber posts.

    Science.gov (United States)

    Križnar, Igor; Jevnikar, Peter; Fidler, Aleš

    2015-02-01

    The study evaluated the micro push-out bond strength of resin material (Multicore Flow) to two types of fiber posts (FP), namely fiber-reinforced composite (FRC) Postec and Radix Fiber posts using Er:YAG laser pretreatment. FP were divided into four groups, two being control groups. Before the core build-up procedure, representative specimens from each group were chosen to determine the surface roughness (Ra) at three different areas using a contact profilometer, while after the procedure, 1.5-mm-thick discs were sectioned and the micro push-out method was used to assess the bond strength of the core build-up material to the fiber post in each group. Two-way analysis of variance was used for statistical analysis with the level of significance set at p post surfaces after Er:YAG laser pretreatment and to classify the failure mode after loading. The type of pretreatment (p post (p post did not (p = 0.965). The mean bond strength in the Er:YAG laser pretreatment group was significantly lower compared to the FRC Postec posts control group (p Fiber posts groups (p = 0.680). Mean Ra values from the Er:YAG laser pretreatment groups were significantly higher compared to control groups (p < 0.001). Er:YAG laser pretreatment at tested parameters negatively affected the bond strength of Multicore to FP and cannot be recommended as a standard procedure.

  19. Suspension-firing of wood with coal ash addition: Probe measurements of ash deposit build-up at Avedøre Power Plant (AVV2)

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    This report is about full-scale probe measurements of deposit build-up and removal conducted at the Avedøreværket Unit 2, a 800 MWth suspension boiler, firing wood and natural gas with the addition of coal ash. Coal ash was used as an additive to capture potassium (K) from wood-firing. Investigat......This report is about full-scale probe measurements of deposit build-up and removal conducted at the Avedøreværket Unit 2, a 800 MWth suspension boiler, firing wood and natural gas with the addition of coal ash. Coal ash was used as an additive to capture potassium (K) from wood......-firing. Investigations of deposit formation rate were made by use of an advanced online ash deposition/shedding probe. Quantification of ash deposition and shedding was made via deposit mass uptake signals obtained from the deposit probe. The influence of coal ash, flue gas temperature, probe surface temperature...... and boiler load on ash deposition propensity was investigated. Results of ash deposition propensity showed increasing trend with increasing flue gas temperature. Video monitoring revealed that the deposits formed were not sticky and could be easily removed, and even at very high flue gas temperatures (> 1350...

  20. Build-up and surface dose measurements on phantoms using micro-MOSFET in 6 and 10 MV x-ray beams and comparisons with Monte Carlo calculations.

    Science.gov (United States)

    Xiang, Hong F; Song, Jun S; Chin, David W H; Cormack, Robert A; Tishler, Roy B; Makrigiorgos, G Mike; Court, Laurence E; Chin, Lee M

    2007-04-01

    This work is intended to investigate the application and accuracy of micro-MOSFET for superficial dose measurement under clinically used MV x-ray beams. Dose response of micro-MOSFET in the build-up region and on surface under MV x-ray beams were measured and compared to Monte Carlo calculations. First, percentage-depth-doses were measured with micro-MOSFET under 6 and 10 MV beams of normal incidence onto a flat solid water phantom. Micro-MOSFET data were compared with the measurements from a parallel plate ionization chamber and Monte Carlo dose calculation in the build-up region. Then, percentage-depth-doses were measured for oblique beams at 0 degrees-80 degrees onto the flat solid water phantom with micro-MOSFET placed at depths of 2 cm, 1 cm, and 2 mm below the surface. Measurements were compared to Monte Carlo calculations under these settings. Finally, measurements were performed with micro-MOSFET embedded in the first 1 mm layer of bolus placed on a flat phantom and a curved phantom of semi-cylindrical shape. Results were compared to superficial dose calculated from Monte Carlo for a 2 mm thin layer that extends from the surface to a depth of 2 mm. Results were (1) Comparison of measurements with MC calculation in the build-up region showed that micro-MOSFET has a water-equivalence thickness (WET) of 0.87 mm for 6 MV beam and 0.99 mm for 10 MV beam from the flat side, and a WET of 0.72 mm for 6 MV beam and 0.76 mm for 10 MV beam from the epoxy side. (2) For normal beam incidences, percentage depth dose agree within 3%-5% among micro-MOSFET measurements, parallel-plate ionization chamber measurements, and MC calculations. (3) For oblique incidence on the flat phantom with micro-MOSFET placed at depths of 2 cm, 1 cm, and 2 mm, measurements were consistent with MC calculations within a typical uncertainty of 3%-5%. (4) For oblique incidence on the flat phantom and a curved-surface phantom, measurements with micro-MOSFET placed at 1.0 mm agrees with the MC

  1. Are neutrons responsible for the dose discrepancies between Monte Carlo calculations and measurements in the build-up region for a high-energy photon beam?

    Energy Technology Data Exchange (ETDEWEB)

    Ding, George X. [Medical Physics, Fraser Valley Cancer Centre, British Columbia Cancer Agency, Surrey, BC (Canada)]. E-mail: gding@bccancer.bc.ca; Duzenli, Cheryl; Kalach, Nina I. [Medical Physics, Fraser Valley Cancer Centre, British Columbia Cancer Agency, Surrey, BC (Canada)

    2002-09-07

    This study presents measured neutron dose using a neutron dosimeter in a water phantom and investigates a hypothesis that neutrons in a high-energy photon beam may be responsible for the reported significant dose discrepancies between Monte Carlo calculations and measurements at the build-up region in large fields. Borated polyethylene slabs were inserted between the accelerator head and the phantom in order to remove neutrons generated in the accelerator head. The thickness of the slab ranged from 2.5 cm to 10 cm. A lead slab of 3 mm thickness was also used in the study. The superheated drop neutron dosimeter was used to measure the depth-dose curve of neutrons in a high-energy photon beam and to verify the effectiveness of the slab to remove these neutrons. Total dose measurements were performed in water using a WELLHOFER WP700 beam scanner with an IC-10 ionization chamber. The Monte Carlo code BEAM was used to simulate an 18 MV photon beam from a Varian Clinac-2100EX accelerator. Both EGS4/DOSXYZ and EGSnrc/DOSRZnrc were used in the dose calculations. Measured neutron dose equivalents as a function of depth per unit total dose in water were presented for 10x10 and 40x40 cm{sup 2} fields. The measured results have shown that a 5-10 cm thick borated polyethylene slab can reduce the neutron dose by a factor of 2 when inserted between the accelerator head and the detector. In all cases the measured neutron dose equivalent was less than 0.5% of the photon dose. In order to study if the ion chamber was highly sensitive to the neutron dose, we have investigated the disagreement between the Monte Carlo calculated and measured central-axis depth-dose curves in the build-up region when different shielding materials were used. The result indicated that the IC-10 chamber was not highly sensitive to the neutron dose. Therefore, neutrons present in a high-energy photon beam were unlikely to be responsible for the reported discrepancies in the build-up region for large fields

  2. Are neutrons responsible for the dose discrepancies between Monte Carlo calculations and measurements in the build-up region for a high-energy photon beam?

    Science.gov (United States)

    Ding, George X; Duzenli, Cheryl; Kalach, Nina I

    2002-09-07

    This study presents measured neutron dose using a neutron dosimeter in a water phantom and investigates a hypothesis that neutrons in a high-energy photon beam may be responsible for the reported significant dose discrepancies between Monte Carlo calculations and measurements at the build-up region in large fields. Borated polyethylene slabs were inserted between the accelerator head and the phantom in order to remove neutrons generated in the accelerator head. The thickness of the slab ranged from 2.5 cm to 10 cm. A lead slab of 3 mm thickness was also used in the study. The superheated drop neutron dosimeter was used to measure the depth-dose curve of neutrons in a high-energy photon beam and to verify the effectiveness of the slab to remove these neutrons. Total dose measurements were performed in water using a WELLHOFER WP700 beam scanner with an IC-10 ionization chamber. The Monte Carlo code BEAM was used to simulate an 18 MV photon beam from a Varian Clinac-2100EX accelerator. Both EGS4/DOSXYZ and EGSnrc/DOSRZnrc were used in the dose calculations. Measured neutron dose equivalents as a function of depth per unit total dose in water were presented for 10 x 10 and 40 x 40 cm2 fields. The measured results have shown that a 5-10 cm thick borated polyethylene slab can reduce the neutron dose by a factor of 2 when inserted between the accelerator head and the detector. In all cases the measured neutron dose equivalent was less than 0.5% of the photon dose. In order to study if the ion chamber was highly sensitive to the neutron dose, we have investigated the disagreement between the Monte Carlo calculated and measured central-axis depth-dose curves in the build-up region when different shielding materials were used. The result indicated that the IC-10 chamber was not highly sensitive to the neutron dose. Therefore, neutrons present in a high-energy photon beam were unlikely to be responsible for the reported discrepancies in the build-up region for large fields.

  3. In vitro performance of self-adhesive resin cements for post-and-core build-ups: influence of chewing simulation or 1-year storage in 0.5% chloramine solution.

    Science.gov (United States)

    Naumann, M; Sterzenbach, G; Rosentritt, M; Beuer, F; Frankenberger, R

    2010-11-01

    The aim of this investigation was to test the in vitro performance of a self-adhesive resin composite core build-up in comparison with two typical conventional etch-and-rinse composite core build-up materials, before and after 1year of storage in 0.5% chloramine solution (LTS). Sixty human maxillary central incisors were divided into three groups. Teeth were root filled and decoronated. Specimens were restored using glass fiber posts cemented with a self-adhesive resin cement. Core build-ups were made with a self-adhesive (U) and two core build-up materials (C and L) applied with their corresponding bonding systems. All specimens received adhesively luted lithium disilicate crowns. Ten specimens of each group were exposed to LTS and examined monthly for cracks or other alterations. All specimens were thermocycled, mechanically loaded (TCML) and finally loaded until failure occurred. There was no statistical significant difference in regard to the number of failures during TCML without and with LTS (log rank: p = 0.225 and 0.609, respectively). The median fracture load values after static loading without LTS and with LTS did not differ significantly (Kruskal-Wallis test: p = 0.057 and 0.106, respectively), though the fracture patterns between the groups without (p = 0.024) and with LTS (p = 0.027) did. Self-adhesive cements used for core build-up have no significantly higher risk of failure compared to conventional core build-up materials in both LTS and TCML test scenarios. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. The development and experimental evaluation of a simple analytical model for the TPR in the build-up region of megavoltage photon beams.

    Science.gov (United States)

    Godin, Marcelo; Galiano, Eduardo

    2012-01-01

    The purpose of this work was to develop a simple analytical model for the tissue phantom ratio (TPR) in the build-up region of megavoltage photon beams and to experimentally evaluate the model under a variety of clinically relevant field configurations. Considering electron contamination and primary photons as the main components of the absorbed dose in the build-up region, an analytic expression for the TPR was derived. The electron contamination component was addressed with a biexponential function; the primary photon component was treated as nonlocal energy transport, i.e., assuming the energy deposited by secondary electrons can be described by a biexponential mode similar to that of contaminating electrons. The model contains five independent constants, which were fitted experimentally. The accuracy of the model was evaluated by comparing its results with in-phantom measurements taken on square, rectangular, irregular, and wedged fields, for 6 and 15 MV photon beams on a GE-Saturne 41 accelerator. More specifically, the accuracy of the model was quantified using the gamma index with 2% dose and 2 mm spatial tolerances as described by Low et al. [Med. Phys. 25, 656-661 (1998)]. For square cerrobende blocked fields, the maximum recorded gamma indices were 0.42 and 0.54 for 6 and 15 MV beams, respectively. For "I" shaped fields, the corresponding maxima were 0.64 and 0.52, respectively, while for "cross" shaped fields they were 0.42 and 0.76. For rectangular 10 × 30 cm fields, the corresponding maxima were 0.32 and 0.42, and for 7 × 20 cm fields, they were 0.70 and 0.35, respectively. For square 10 × 10 cm and 15 × 15 cm fields with an acrylic tray, the maxima were 0.57 and 0.45 for 6 MV and 0.32 and 0.77 for 15 MV beams, respectively. For a 10 × 10 cm 60° wedged field, the maxima were 0.53 and 0.33 for 6 and 15 MV beams, respectively. In all examined cases of irregular, rectangular, square (with and without tray), and wedged fields, the

  5. AAA and PBC calculation accuracy in the surface build-up region in tangential beam treatments. Phantom and breast case study with the Monte Carlo code PENELOPE.

    Science.gov (United States)

    Panettieri, Vanessa; Barsoum, Pierre; Westermark, Mathias; Brualla, Lorenzo; Lax, Ingmar

    2009-10-01

    In tangential beam treatments accurate dose calculation of the absorbed dose in the build-up region is of major importance, in particular when the target has superficial extension close to the skin. In most analytical treatment planning systems (TPSs) calculations depend on the experimental measurements introduced by the user in which accuracy might be limited by the type of detector employed to perform them. To quantify the discrepancy between analytically calculated and delivered dose in the build-up region, near the skin of a patient, independent Monte Carlo (MC) simulations using the penelope code were performed. Dose distributions obtained with MC simulations were compared with those given by the Pencil Beam Convolution (PBC) algorithm and the Analytical Anisotropic Algorithm (AAA) implemented in the commercial TPS Eclipse. A cylindrical phantom was used to approximate the breast contour of a patient for MC simulations and the TPS. Calculations of the absorbed doses were performed for 6 and 18MV beams for four different angles of incidence: 15 degrees , 30 degrees , 45 degrees and 75 degrees and different field sizes: 3x3cm(2), 10x10cm(2) and 40x40cm(2). Absorbed doses along the phantom central axis were obtained with both the PBC algorithm and the AAA and compared to those estimated by the MC simulations. Additionally, a breast patient case was calculated with two opposed 6MV photon beams using all the aforementioned analytical and stochastic algorithms. For the 6MV photon beam in the phantom case, both the PBC algorithm and the AAA tend to underestimate the absorbed dose in the build-up region in comparison to MC results. These differences are clinically irrelevant and are included in a 1mm range. This tendency is also confirmed in the breast patient case. For the 18MV beam the PBC algorithm underestimates the absorbed dose with respect to the AAA. In comparison to MC simulations the PBC algorithm tends to underestimate the dose after the first 2-3mm of

  6. Mitigation of Volatile Fatty Acid Build-Up by the Use of Soft Carbon Felt Electrodes: Evaluation of Anaerobic Digestion in Acidic Conditions

    Directory of Open Access Journals (Sweden)

    Rubén Moreno

    2018-01-01

    Full Text Available Anaerobic digestion and bioelectrochemical systems have great potential to recover energy from waste streams and help overcome common hurdles associated with this process, as integrated technologies. In this study, the benefit of integrating an electrogen-enriched bioanode in a batch anaerobic digester was explored under ambient temperature conditions associated with organic overloading and reactor acidity. An increase in CH4 production was observed in the electrode-containing reactors (0.56 L CH4 kgVS−1 h−1 in comparison with the conventional anaerobic digester (0.14 L CH4 kgVS−1 h−1 during the initial stages of operation. In addition, the mere presence of electrodes operating in open circuit mode resulted in a delay in volatile fatty acid (VFA build-up. This seems to be associated with the enhancement in VFA consumption due to biomass proliferation on the electrode surface, rather than on electrochemical activity.

  7. Study of the effect of external heating and internal temperature build-up during polymerization on the morphology of porous polymethacrylate adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Chan Yi, E-mail: vicchanyiwei@hotmail.com; Ongkudon, Clarence M., E-mail: clarence@ums.edu.my; Kansil, Tamar, E-mail: tamarkansil87@gmail.com [Biotechnology Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah (Malaysia)

    2015-07-22

    Modern day synthesis protocols of methacrylate monolithic polymer adsorbent are based on existing polymerization blueprint without a thorough understanding of the dynamics of pore structure and formation. This has resulted in unproductiveness of polymer adsorbent consequently affecting purity and recovery of final product, productivity, retention time and cost effectiveness of the whole process. The problems magnified in monolith scaling-up where internal heat buildup resulting from external heating and high exothermic polymerization reaction was reflected in cracking of the adsorbent. We believe that through careful and precise control of the polymerization kinetics and parameters, it is possible to prepare macroporous methacrylate monolithic adsorbents with controlled pore structures despite being carried out in an unstirred mould. This research involved the study of the effect of scaling-up on pore morphology of monolith, in other words, porous polymethacrylate adsorbents that were prepared via bulk free radical polymerization process by imaging the porous morphology of polymethacrylate with scanning electron microscope.

  8. Does the seed bank contribute to the build-up of a genetic extinction debt in the grassland perennial Campanula rotundifolia?

    Science.gov (United States)

    Plue, Jan; Vandepitte, Katrien; Honnay, Olivier; Cousins, Sara A O

    2017-09-01

    Habitat fragmentation threatens global biodiversity. Many plant species persist in habitat fragments via persistent life cycle stages such as seed banks, generating a species extinction debt. Here, seed banks are hypothesized to cause a temporal delay in the expected loss of genetic variation, which can be referred to as a genetic extinction debt, as a possible mechanism behind species extinction debts. Fragmented grassland populations of Campanula rotundifolia were examined for evidence of a genetic extinction debt, investigating if the seed bank contributed to the extinction debt build-up. The genetic make-up of 15 above- and below-ground populations was analysed in relation to historical and current levels of habitat fragmentation, both separately and combined. Genetic diversity was highest in above-ground populations, though below-ground populations contained 8 % of unique alleles that were absent above-ground. Above-ground genetic diversity and composition were related to historical patch size and connectivity, but not current patch characteristics, suggesting the presence of a genetic extinction debt in the above-ground populations. No such relationships were found for the below-ground populations. Genetic diversity measures still showed a response to historical but not present landscape characteristics when combining genetic diversity of the above- and below-ground populations. The fragmented C. rotundifolia populations exhibited a genetic extinction debt. However, the role of the seed banks in the build-up of this extinction debt is probably small, since the limited, unique genetic diversity of the seed bank alone seems unable to counter the detrimental effects of habitat fragmentation on the population genetic structure of C. rotundifolia.

  9. The influence of modified water chemistries on metal oxide films, activity build-up and stress corrosion cracking of structural materials in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Maekelae, K.; Laitinen, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

    1999-03-01

    The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for {sup 60}Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (orig.) 127 refs.

  10. An assessment of fracture resistance of three composite resin core build-up materials on three prefabricated non-metallic posts, cemented in endodontically treated teeth: an in vitro study.

    Science.gov (United States)

    Kumar, Lalit; Pal, Bhupinder; Pujari, Prashant

    2015-01-01

    Endodontically treated teeth with excessive loss of tooth structure would require to be restored with post and core to enhance the strength and durability of the tooth and to achieve retention for the restoration. The non-metallic posts have a superior aesthetic quality. Various core build-up materials can be used to build-up cores on the posts placed in endodontically treated teeth. These materials would show variation in their bonding with the non-metallic posts thus affecting the strength and resistance to fracture of the remaining tooth structure. Aims. The aim of the study was to assess the fracture resistance of three composite resin core build-up materials on three prefabricated non-metallic posts, cemented in extracted endodontically treated teeth. Material and Methods. Forty-five freshly extracted maxillary central incisors of approximately of the same size and shape were selected for the study. They were divided randomly into 3 groups of 15 each, depending on the types of non-metallic posts used. Each group was further divided into 3 groups (A, B and C) of 5 samples each depending on three core build-up material used. Student's unpaired 't' test was also used to analyse and compare each group with the other groups individually, and decide whether their comparisons were statistically significant. Results. Luxacore showed the highest fracture resistance among the three core build-up materials with all the three posts systems. Ti-core had intermediate values of fracture resistance and Lumiglass had the least values of fracture resistance.

  11. HSRL-2 Observations of Aerosol Variability During an Aerosol Build-up Event in Houston and Comparisons With WRF-Chem

    Science.gov (United States)

    Burton, Sharon P.; Saide, Pablo; Sawamura, Patricia; Hostetler, Chris; Ferrare, Rich; Scarino, Amy Jo; Berkoff, Tim; Harper, David; Cook, Tony; Rogers, Ray; hide

    2015-01-01

    The NASA Langley airborne multi-wavelength High Spectral Resolution Lidar (HSRL-2) provides vertical distribution of aerosol optical properties as curtains of aerosol extinction, backscatter and depolarization along the flight track, plus intensive properties that are used to infer aerosol type and external mixing of types. Deployed aboard the NASA Langley King Air on the DISCOVER-AQ field mission in Houston in September 2013, HSRL-2 flew a pattern that included 18 ground sites, repeated four times a day, coordinated with a suite of airborne in situ measurements. The horizontally and vertically resolved curtains of HSRL-2 measurements give an unparalleled view of the spatial and temporal variability of aerosol, which provide broad context for interpreting other measurements and models. Detailed comparisons of aerosol extinction are made with the WRF-Chem chemical transport model along the HSRL-2 flight path. The period from Sept. 11-14 is notable for a large aerosol build-up and persistent smoke layers. We investigate the aerosol properties using the vertically resolved HSRL-2 measurements and aerosol typing analysis plus WRFChem model tracers and back trajectories, and modeling of humidification effects.

  12. Observational study on the fine structure and dynamics of a solar jet. I. Energy build-up process around a satellite spot

    Science.gov (United States)

    Sakaue, Takahito; Tei, Akiko; Asai, Ayumi; Ueno, Satoru; Ichimoto, Kiyoshi; Shibata, Kazunari

    2017-10-01

    We report on a solar jet phenomenon associated with successive flares on 2014 November 10. These explosive events were involved with the satellite spots' emergence around a δ-type sunspot in the decaying active region NOAA 12205. The data for this jet were provided by the Solar Dynamics Observatory, the X-Ray Telescope aboard Hinode, and the Interface Region Imaging Spectrograph and Domeless Solar Telescope at Hida Observatory, Kyoto University. These abundant data enabled us to present this series of papers to discuss the entire process of the observed phenomena, including the energy storage, event trigger, and energy release. In this paper, we focus on the energy build-up and trigger phases, by analyzing the photospheric horizontal flow field around the active region by an optical flow method. The analysis shows the following results: (1) The observed explosive phenomena involved three satellite spots, the magnetic fluxes of which successively reconnected with their pre-existing ambient fields; (2) All of these satellite spots emerged in the moat region of a pivotal δ-type sunspot, especially near its convergent boundary with the neighboring supergranules or moat regions of adjacent sunspots; (3) Around the jet ejection site, the positive polarities of the satellite spot and adjacent emerging flux encountered the global magnetic field with a negative polarity in the moat region of the pivotal δ-type sunspot, and thus the polarity inversion line was formed along the convergent boundary of the photospheric horizontal flow channels.

  13. Applying Petroleum the Pressure Buildup Well Test Procedure on Thermal Response Test—A Novel Method for Analyzing Temperature Recovery Period

    Directory of Open Access Journals (Sweden)

    Tomislav Kurevija

    2018-02-01

    Full Text Available The theory of Thermal Response Testing (TRT is a well-known part of the sizing process of the geothermal exchange system. Multiple parameters influence the accuracy of effective ground thermal conductivity measurement; like testing time, variable power, climate interferences, groundwater effect, etc. To improve the accuracy of the TRT, we introduced a procedure to additionally analyze falloff temperature decline after the power test. The method is based on a premise of analogy between TRT and petroleum well testing, since the origin of both procedures lies in the diffusivity equation with solutions for heat conduction or pressure analysis during radial flow. Applying pressure build-up test interpretation techniques to borehole heat exchanger testing, greater accuracy could be achieved since ground conductivity could be obtained from this period. Analysis was conducted on a coaxial exchanger with five different power steps, and with both direct and reverse flow regimes. Each test was set with 96 h of classical TRT, followed by 96 h of temperature decline, making for almost 2000 h of cumulative borehole testing. Results showed that the ground conductivity value could vary by as much as 25%, depending on test time, seasonal period and power fluctuations, while the thermal conductivity obtained from the falloff period provided more stable values, with only a 10% value variation.

  14. Is mechanical retention for adhesive core build-up needed to restore a vital tooth with a monolithic zirconium crown? - An in vitro study.

    Science.gov (United States)

    Walczak, Katarzyna; Rues, Stefan; Wieckiewicz, Mieszko; Range, Ursula; Schmitter, Marc

    2016-01-01

    To show the influence of retentive cavity, cavity wall preparation and different luting techniques on the fracture resistance of severely damaged teeth restored with adhesive core build-ups and monolithic zirconium crowns. Extracted molars were prepared with 2 mm ferrule height and divided into eleven groups (n = 8/group). In nine groups a retentive occlusal cavity with a width and depth of 1 or 2 mm was prepared. Two control groups without a retentive cavity were made. Zirconium crowns were manufactured. 48 copings were cemented with glass-ionomer cement (Ketac Cem), the others (n = 40) with adhesive resin cement (Panavia F 2.0). Artificial ageing was carried out in the following way: n = 88, thermocycling (10,000 cycles, 6° C/60° C), n = 80 chewing simulation (1,200,000 cycles, 64 N). The samples were tested for load at first damage and fracture load with non-axial force. For statistical analysis ANCOVA with post hoc, Bonferroni-adjusted t-test were used ( p ≤ 0.05). No differences between the tested cements were detected. Influence of the cavity wall thickness was significant ( p = 0.001). Mostly, the samples with wall thickness of 2 mm showed better results. Both control groups (no cavity) showed results comparable to study groups with cavity. Retentive cavity is most likely not mandatory. However, if prepared, the cavity wall thickness is of higher importance than cavity depth. Glass-ionomer and adhesive resin cement are comparable for use with zirconia crowns.

  15. Electrophoretic build-up of alternately multilayered films and micropatterns based on graphene sheets and nanoparticles and their applications in flexible supercapacitors.

    Science.gov (United States)

    Niu, Zhiqiang; Du, Jianjun; Cao, Xuebo; Sun, Yinghui; Zhou, Weiya; Hng, Huey Hoon; Ma, Jan; Chen, Xiaodong; Xie, Sishen

    2012-10-22

    Graphene nanosheets and metal nanoparticles (NPs) have been used as nano-building-blocks for assembly into macroscale hybrid structures with promising performance in electrical devices. However, in most graphene and metal NP hybrid structures, the graphene sheets and metal NPs (e.g., AuNPs) do not enable control of the reaction process, orientation of building blocks, and organization at the nanoscale. Here, an electrophoretic layer-by-layer assembly for constructing multilayered reduced graphene oxide (RGO)/AuNP films and lateral micropatterns is presented. This assembly method allows easy control of the nano-architecture of building blocks along the normal direction of the film, including the number and thickness of RGO and AuNP layers, in addition to control of the lateral orientation of the resultant multilayered structures. Conductivity of multilayered RGO/AuNP hybrid nano-architecture shows great improvement caused by a bridging effect of the AuNPs along the out-of-plane direction between the upper and lower RGO layers. The results clearly show the potential of electrophoretic build-up in the fabrication of graphene-based alternately multilayered films and patterns. Finally, flexible supercapacitors based on multilayered RGO/AuNP hybrid films are fabricated, and excellent performance, such as high energy and power densities, are achieved. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Energy balance and assessment of the pressure build-up around a bolt fastener due to sparking during a lightning impact

    Science.gov (United States)

    Teulet, Philippe; Billoux, Tommy; Cressault, Yann; Masquère, Mathieu; Gleizes, Alain; Revel, Ivan; Lepetit, Bruno; Peres, Gilles

    2017-03-01

    This work is devoted to the calculation of the energy balance associated with the formation of an electric arc between the bolt shank and an inner structural part of the fuselage during a lightning strike. Assessment of the pressure build-up in the confined volume around the bolt fastener has also been performed. This pressure rise comes from the temperature increase and from the mass density increase (melting and vaporisation of materials). Previous electrical measurements performed by Airbus Group during a lightning test campaign have been used to calculate the total available electrical energy. The energies necessary for melting and vaporisation of bolt and rib are derived from thermodynamic properties of aluminium and titanium. A numerical code has been developed to determine the chemical composition (under the local thermodynamic equilibrium [LTE] assumption) and the internal energy of the plasma for air-Al/Ti mixtures. Plasma and material radiation losses and heat conduction losses have also been evaluated. Finally, an analytical model has been implemented to determine the overpressure as a function of the deposited electrical energy, the energy involved in the arc formation, the energy necessary for melting and the plasma composition and mass density. With this approach, maximum pressure values are in the range 200-330 bars.

  17. Trace organic solutes in closed-loop forward osmosis applications: influence of membrane fouling and modeling of solute build-up.

    Science.gov (United States)

    D'Haese, Arnout; Le-Clech, Pierre; Van Nevel, Sam; Verbeken, Kim; Cornelissen, Emile R; Khan, Stuart J; Verliefde, Arne R D

    2013-09-15

    In this study, trace organics transport in closed-loop forward osmosis (FO) systems was assessed. The FO systems considered, consisted of an FO unit and a nanofiltration (NF) or reverse osmosis (RO) unit, with the draw solution circulating between both units. The rejection of trace organics by FO, NF and RO was tested. It was found that the rejection rates of FO were generally comparable with NF and lower than RO rejection rates. To assess the influence of fouling in FO on trace organics rejection, FO membranes were fouled with sodium alginate, bovine serum albumin or by biofilm growth, after which trace organics rejection was tested. A negative influence of fouling on FO rejection was found which was limited in most cases, while it was significant for some compounds such as paracetamol and naproxen, indicating specific compound-foulant interactions. The transport mechanism of trace organics in FO was tested, in order to differentiate between diffusive and convective transport. The concentration of trace organics in the final product water and the build-up of trace organics in the draw solution were modeled assuming the draw solution was reconcentrated by NF/RO and taking into account different transport mechanisms for the FO membrane and different rejection rates by NF/RO. Modeling results showed that if the FO rejection rate is lower than the RO rejection rate (as is the case for most compounds tested), the added value of the FO-RO cycle compared to RO only at steady-state was small for diffusively and negative for convectively transported trace organics. Modeling also showed that trace organics accumulate in the draw solution. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Soil environmental conditions and microbial build-up mediate the effect of plant diversity on soil nitrifying and denitrifying enzyme activities in temperate grasslands.

    Directory of Open Access Journals (Sweden)

    Xavier Le Roux

    Full Text Available Random reductions in plant diversity can affect ecosystem functioning, but it is still unclear which components of plant diversity (species number - namely richness, presence of particular plant functional groups, or particular combinations of these and associated biotic and abiotic drivers explain the observed relationships, particularly for soil processes. We assembled grassland communities including 1 to 16 plant species with a factorial separation of the effects of richness and functional group composition to analyze how plant diversity components influence soil nitrifying and denitrifying enzyme activities (NEA and DEA, respectively, the abundance of nitrifiers (bacterial and archaeal amoA gene number and denitrifiers (nirK, nirS and nosZ gene number, and key soil environmental conditions. Plant diversity effects were largely due to differences in functional group composition between communities of identical richness (number of sown species, though richness also had an effect per se. NEA was positively related to the percentage of legumes in terms of sown species number, the additional effect of richness at any given legume percentage being negative. DEA was higher in plots with legumes, decreased with increasing percentage of grasses, and increased with richness. No correlation was observed between DEA and denitrifier abundance. NEA increased with the abundance of ammonia oxidizing bacteria. The effect of richness on NEA was entirely due to the build-up of nitrifying organisms, while legume effect was partly linked to modified ammonium availability and nitrifier abundance. Richness effect on DEA was entirely due to changes in soil moisture, while the effects of legumes and grasses were partly due to modified nitrate availability, which influenced the specific activity of denitrifiers. These results suggest that plant diversity-induced changes in microbial specific activity are important for facultative activities such as denitrification

  19. Effect of composite surface treatment and aging on the bond strength between a core build-up composite and a luting agent.

    Science.gov (United States)

    Cotes, Caroline; Cardoso, Mayra; Melo, Renata Marques de; Valandro, Luiz Felipe; Bottino, Marco Antonio

    2015-01-01

    The purpose of this study was to assess the influence of conditioning methods and thermocycling on the bond strength between composite core and resin cement. Eighty blocks (8×8×4 mm) were prepared with core build-up composite. The cementation surface was roughened with 120-grit carbide paper and the blocks were thermocycled (5,000 cycles, between 5°C and 55°C, with a 30 s dwell time in each bath). A layer of temporary luting agent was applied. After 24 h, the layer was removed, and the blocks were divided into five groups, according to surface treatment: (NT) No treatment (control); (SP) Grinding with 120-grit carbide paper; (AC) Etching with 37% phosphoric acid; (SC) Sandblasting with 30 mm SiO2 particles, silane application; (AO) Sandblasting with 50 mm Al2O3 particles, silane application. Two composite blocks were cemented to each other (n=8) and sectioned into sticks. Half of the specimens from each block were immediately tested for microtensile bond strength (µTBS), while the other half was subjected to storage for 6 months, thermocycling (12,000 cycles, between 5°C and 55°C, with a dwell time of 30 s in each bath) and µTBS test in a mechanical testing machine. Bond strength data were analyzed by repeated measures two-way ANOVA and Tukey test (α=0.05). The µTBS was significantly affected by surface treatment (p=0.007) and thermocycling (p=0.000). Before aging, the SP group presented higher bond strength when compared to NT and AC groups, whereas all the other groups were statistically similar. After aging, all the groups were statistically similar. SP submitted to thermocycling showed lower bond strength than SP without thermocycling. Core composites should be roughened with a diamond bur before the luting process. Thermocycling tends to reduce the bond strength between composite and resin cement.

  20. Influence of light-exposure methods and depths of cavity on the microhardness of dual-cured core build-up resin composites

    Science.gov (United States)

    YOSHIDA, Keiichi; MENG, Xiangfeng

    2014-01-01

    Objective The purpose of this study was to evaluate the Knoop hardness number (KHN) of dual-cured core build-up resin composites (DCBRCs) at 6 depths of cavity after 3 post-irradiation times by 4 light-exposure methods. Material and Methods Five specimens each of DCBRCs (Clearfil DC Core Plus [DCP] and Unifil Core EM [UCE]) were filled in acrylic resin blocks with a semi-cylindrical cavity and light-cured using an LED light unit (power density: 1,000 mW/cm2)at the top surface by irradiation for 20 seconds (20 s), 40 seconds (40 s), bonding agent plus 20 seconds (B+20 s), or 40 seconds plus light irradiation of both sides of each acrylic resin block for 40 seconds each (120 s). KHN was measured at depths of 0.5, 2.0, 4.0, 6.0, 8.0, and 10.0 mm at 0.5 hours, 24 hours, and 7 days post-irradiation. Statistical analysis was performed using repeated measures ANOVA and Tukey's compromise post-hoc test with a significance level of p0.05). In DCP, and not UCE, at 24 hours and 7 days post-irradiation, the B+20 s method showed significantly higher KHN at all depths of cavity, except the depth of 0.5 mm (p<0.05). Conclusion KHN depends on the light-exposure method, use of bonding agent, depth of cavity, post-irradiation time, and material brand. Based on the microhardness behavior, DCBRCs are preferably prepared by the effective exposure method, when used for a greater depth of cavity. PMID:24626248

  1. Build-ups in the supply chain of the brain: on the neuroenergetic cause of obesity and type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Achim Peters

    2009-04-01

    Full Text Available Obesity and type 2 diabetes have become the major health problems in many industrialized countries. A few theoretical frameworks have been set up to derive the possible determinative cause of obesity. One concept views that food availability determines food intake, i.e. that obesity is the result of an external energy “push” into the body. Another one views that the energy milieu within the human organism determines food intake, i.e. that obesity is due to an excessive “pull” from inside the organism. Here we present the unconventional concept that a healthy organism is maintained by a „competent brain-pull“ which serves systemic homeostasis, and that the underlying cause of obesity is “incompetent brain-pull”, i.e. that the brain is unable to properly demand glucose from the body. We describe the energy fluxes from the environment, through the body, towards the brain with a mathematical “supply chain” model and test whether its predictions fit medical and experimental data sets from our and other research groups. In this way, we show data-based support of our hypothesis, which states that under conditions of food abundance incompetent brain-pull will lead to build-ups in the supply chain culminating in obesity and type 2 diabetes. In the same way, we demonstrate support of the related hypothesis, which states that under conditions of food deprivation a competent brain-pull mechanism is indispensable for the continuance of the brain´s high energy level. In conclusion, we took the viewpoint of integrative physiology and provided evidence for the necessity of brain-pull mechanisms for the benefit of health. Along these lines, our work supports recent molecular findings from the field of neuroenergetics and continues the work on the “Selfish Brain” theory dealing with the maintenance of the cerebral and peripheral energy homeostasis.

  2. Improved evaluation of pressure build-up measurements of gas probes using the downhole shutin tool; Verbesserung der Auswertung von Druckaufbaumessungen von Gassonden durch Einsatz des Downhole-Shutin-Tools

    Energy Technology Data Exchange (ETDEWEB)

    Mantatzis, K.; Seywald, M. [Rohoel-Aufsuchungs AG (RAG), Vienna (Austria)

    2007-09-13

    Three pressure build-up measurements of gas probes are presented in which a downhole shutin tool (DHSIT) and RAG measuring equipment were used. In past measurements, it was often observed especially in dense formations that longer wellbore storage resulted in interpretation problems of Kh and skin in pressure transient analysis. It was also investigated inhowfar quantification of phase separation effects can be improved. For this purpose, three probes were selected for PfP measurements with DHSIT. (orig.)

  3. Effect of composite surface treatment and aging on the bond strength between a core build-up composite and a luting agent

    Science.gov (United States)

    COTES, Caroline; CARDOSO, Mayra; de MELO, Renata Marques; VALANDRO, Luiz Felipe; BOTTINO, Marco Antonio

    2015-01-01

    Objective The purpose of this study was to assess the influence of conditioning methods and thermocycling on the bond strength between composite core and resin cement. Material and Methods Eighty blocks (8×8×4 mm) were prepared with core build-up composite. The cementation surface was roughened with 120-grit carbide paper and the blocks were thermocycled (5,000 cycles, between 5°C and 55°C, with a 30 s dwell time in each bath). A layer of temporary luting agent was applied. After 24 h, the layer was removed, and the blocks were divided into five groups, according to surface treatment: (NT) No treatment (control); (SP) Grinding with 120-grit carbide paper; (AC) Etching with 37% phosphoric acid; (SC) Sandblasting with 30 mm SiO2 particles, silane application; (AO) Sandblasting with 50 mm Al2O3 particles, silane application. Two composite blocks were cemented to each other (n=8) and sectioned into sticks. Half of the specimens from each block were immediately tested for microtensile bond strength (µTBS), while the other half was subjected to storage for 6 months, thermocycling (12,000 cycles, between 5°C and 55°C, with a dwell time of 30 s in each bath) and µTBS test in a mechanical testing machine. Bond strength data were analyzed by repeated measures two-way ANOVA and Tukey test (α=0.05). Results The µTBS was significantly affected by surface treatment (p=0.007) and thermocycling (p=0.000). Before aging, the SP group presented higher bond strength when compared to NT and AC groups, whereas all the other groups were statistically similar. After aging, all the groups were statistically similar. SP submitted to thermocycling showed lower bond strength than SP without thermocycling. Conclusion Core composites should be roughened with a diamond bur before the luting process. Thermocycling tends to reduce the bond strength between composite and resin cement. PMID:25760269

  4. Effect of composite surface treatment and aging on the bond strength between a core build-up composite and a luting agent

    Directory of Open Access Journals (Sweden)

    Caroline COTES

    2015-02-01

    Full Text Available Objective The purpose of this study was to assess the influence of conditioning methods and thermocycling on the bond strength between composite core and resin cement. Material and Methods Eighty blocks (8×8×4 mm were prepared with core build-up composite. The cementation surface was roughened with 120-grit carbide paper and the blocks were thermocycled (5,000 cycles, between 5°C and 55°C, with a 30 s dwell time in each bath. A layer of temporary luting agent was applied. After 24 h, the layer was removed, and the blocks were divided into five groups, according to surface treatment: (NT No treatment (control; (SP Grinding with 120-grit carbide paper; (AC Etching with 37% phosphoric acid; (SC Sandblasting with 30 mm SiO2 particles, silane application; (AO Sandblasting with 50 mm Al2O3 particles, silane application. Two composite blocks were cemented to each other (n=8 and sectioned into sticks. Half of the specimens from each block were immediately tested for microtensile bond strength (µTBS, while the other half was subjected to storage for 6 months, thermocycling (12,000 cycles, between 5°C and 55°C, with a dwell time of 30 s in each bath and µTBS test in a mechanical testing machine. Bond strength data were analyzed by repeated measures two-way ANOVA and Tukey test (α=0.05. Results The µTBS was significantly affected by surface treatment (p=0.007 and thermocycling (p=0.000. Before aging, the SP group presented higher bond strength when compared to NT and AC groups, whereas all the other groups were statistically similar. After aging, all the groups were statistically similar. SP submitted to thermocycling showed lower bond strength than SP without thermocycling. Conclusion Core composites should be roughened with a diamond bur before the luting process. Thermocycling tends to reduce the bond strength between composite and resin cement.

  5. HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

    Directory of Open Access Journals (Sweden)

    M. Raivonen

    2017-12-01

    Full Text Available Wetlands are one of the most significant natural sources of methane (CH4 to the atmosphere. They emit CH4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH4, in addition to carbon dioxide (CO2. Production of CH4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH4 emissions are thus needed for upscaling observations to estimate present CH4 emissions and for producing scenarios of future atmospheric CH4 concentrations. Aiming at a CH4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI of aerenchymatous peatland vegetation, and water table depth (WTD, it simulates the concentrations and transport of CH4, CO2, and oxygen (O2 in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness, and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1 the model is flexible and robust and thus suitable for different environments; (2 the simulated CH4 emissions largely depend on the prescribed rate of anoxic respiration; (3 the sensitivity of the total CH4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular

  6. Galaxy stellar mass functions from ZFOURGE/CANDELS: An excess of low-mass galaxies since z = 2 and the rapid buildup of quiescent galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Tomczak, Adam R.; Tran, Kim-Vy H.; Papovich, Casey; Kawinwanichakij, Lalitwadee; Mehrtens, Nicola; Spitler, Lee R.; Tilvi, Vithal [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Quadri, Ryan F.; Kelson, Daniel D.; McCarthy, Patrick J.; Monson, Andrew J.; Persson, S. Eric [Carnegie Observatories, Pasadena, CA 91101 (United States); Labbé, Ivo; Straatman, Caroline M. S. [Sterrewacht Leiden, Leiden University, NL-2300 RA Leiden (Netherlands); Glazebrook, Karl; Allen, Rebecca; Kacprzak, Glenn G. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Brammer, Gabriel B. [European Southern Observatory, Alonso de Córdova 3107, Casilla 19001, Vitacura, Santiago (Chile); Van Dokkum, Pieter, E-mail: tomczak@physics.tamu.edu [Department of Astronomy, Yale University, New Haven, CT 06520 (United States)

    2014-03-10

    Using observations from the FourStar Galaxy Evolution Survey (ZFOURGE), we obtain the deepest measurements to date of the galaxy stellar mass function (SMF) at 0.2 < z < 3. ZFOURGE provides well-constrained photometric redshifts made possible through deep medium-bandwidth imaging at 1-2 μm. We combine this with Hubble Space Telescope imaging from the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey, allowing for the efficient selection of both blue and red galaxies down to stellar masses of ∼10{sup 9.5} M {sub ☉} at z ∼ 2.5. The total surveyed area is 316 arcmin{sup 2} distributed over three independent fields. We supplement these data with the wider and shallower NEWFIRM Medium-Band Survey to provide stronger constraints at high masses. Several studies at z ≤ 1.5 have revealed a steepening of the slope at the low-mass end of the SMF, leading to an upturn at masses <10{sup 10} M {sub ☉} that is not well described by a standard single-Schechter function. We find evidence that this feature extends to at least z ∼ 2 and that it can be found in both the star-forming and quiescent populations individually. The characteristic mass (M*) and slope at the lowest masses (α) of a double-Schechter function fit to the SMF stay roughly constant at Log(M/M {sub ☉}) ∼ 10.65 and ∼ – 1.5, respectively. The SMF of star-forming galaxies has evolved primarily in normalization, while the change in shape is relatively minor. Our data allow us, for the first time, to observe a rapid buildup at the low-mass end of the quiescent SMF. Since z = 2.5, the total stellar mass density of quiescent galaxies (down to 10{sup 9} M {sub ☉}) has increased by a factor of ∼12, whereas the mass density of star-forming galaxies only increases by a factor of ∼2.2.

  7. Determining relative proton-proton proximities from the build-up of two-dimensional correlation peaks in 1H double-quantum MAS NMR: insight from multi-spin density-matrix simulations.

    Science.gov (United States)

    Bradley, Jonathan P; Tripon, Carmen; Filip, Claudiu; Brown, Steven P

    2009-08-28

    The build-up of intensity-as a function of the number, n(rcpl), of POST-C7 elements used for the excitation and reconversion of double-quantum (DQ) coherence (DQC)-is analysed for the fifteen distinct DQ correlation peaks that are observed experimentally for the eight separate (1)H resonances in a (1)H (500 MHz) DQ CRAMPS solid-state (12.5 kHz MAS) NMR spectrum of the dipeptide beta-AspAla (S. P. Brown, A. Lesage, B. Elena, and L. Emsley, J. Am. Chem. Soc., 2004, 126, 13230). The simulation in SPINEVOLUTION (M. Veshtort and R. G. Griffin, J. Magn. Reson., 2006, 178, 248) of t(1) ((1)H DQ evolution) FIDs for clusters of eight dipolar-coupled protons gives separate simulated (1)H DQ build-up curves for the CH(2)(a), CH(2)(b), CH(Asp), CH(Ala), NH and OH (1)H single-quantum (SQ) (1)H resonances. An analysis of both the simulated and experimental (1)H DQ build-up leads to the following general observations: (i) considering the build-up of (1)H DQ peaks at a particular SQ frequency, maximum intensity is observed for the DQC corresponding to the shortest H-H distance; (ii) for the maximum intensity (1)H DQ peak at a particular SQ frequency, the recoupling time for the observed maximum intensity depends on the corresponding H-H distance, e.g., maximum intensity for the CH(2)(a)-CH(2)(b) (H-H distance = 1.55 A) and OH-CH(Asp) (H-H distance = 2.49 A) DQ peaks is observed at n(rcpl) = 2 and 3, respectively; (iii) for DQ peaks involving a CH(2) proton at a non-CH(2) SQ frequency, there is much reduced intensity and a maximum intensity at a short recoupling time; (iv) for the other lower intensity (1)H DQ peaks at a particular SQ frequency, maximum intensity is observed for the same (or close to the same) recoupling time, but the relative intensity of the DQ peaks is a reliable indicator of the relative H-H distance-the ratio of the maximum intensities for the peaks at the CH(Ala) SQ frequency due to the two DQCs with the NH and OH protons are found to be approximately in the

  8. Morphology, structure, composition and build-up processes of the active channel-mouth lobe complex of the Congo deep-sea fan with inputs from remotely operated underwater vehicle (ROV) multibeam and video surveys

    Science.gov (United States)

    Dennielou, Bernard; Droz, Laurence; Babonneau, Nathalie; Jacq, Céline; Bonnel, Cédric; Picot, Marie; Le Saout, Morgane; Saout, Yohan; Bez, Martine; Savoye, Bruno; Olu, Karine; Rabouille, Christophe

    2017-08-01

    The detailed structure and composition of turbiditic channel-mouth lobes is still largely unknown because they commonly lie at abyssal water depths, are very thin and are therefore beyond the resolution of hull-mound acoustic tools. The morphology, structure and composition of the Congo turbiditic channel-mouth lobe complex (90×40 km; 2525 km2) were investigated with hull-mounted swath bathymetry, air gun seismics, 3.5 kHz sub-bottom profiler, sediment piston cores and also with high-resolution multibeam bathymetry and video acquired with a Remote Operating Vehicle (ROV). The lobe complex lies 760 km off the Congo River mouth in the Angola abyssal plain between 4740 and 5030 m deep. It is active and is fed by turbidity currents that deposit several centimetres of sediment per century. The lobe complex is subdivided into five lobes that have prograded. The lobes are dominantly muddy. Sand represents ca. 13% of the deposits and is restricted to the feeding channel and distributaries. The overall lobe body is composed of thin muddy to silty turbidites. The whole lobe complex is characterized by in situ mass wasting (slumps, debrites). The 1-m-resolution bathymetry shows pervasive slidings and block avalanches on the edges of the feeding channel and the channel mouth indicating that sliding occurs early and continuously in the lobe build-up. Mass wasting is interpreted as a consequence of very-high accumulation rates, over-steepening and erosion along the channels and is therefore an intrinsic process of lobe building. The bifurcation of feeding channels is probably triggered when the gradient in the distributaries at the top of a lobe becomes flat and when turbidity currents find their way on the higher gradient on the lobe side. It may also be triggered by mass wasting on the lobe side. When a new lobe develops, the abandoned lobes continue to collect significant turbiditic deposits from the feeding channel spillover, so that the whole lobe complex remains active. A

  9. Delta method, an empirical drag buildup technique

    Science.gov (United States)

    Feagin, R. C.; Morrison, W. D.

    1978-01-01

    An empirical drag correlation technique was developed from analysis of 19 subsonic and supersonic military aircraft and 15 advanced or supercritical airfoil configurations which can be applied in conceptual and advanced aircraft design activities. The Delta Method may be used for estimating the clean wing drag polar for cruise and maneuver conditions up to buffet onset, and to approximately Mach 2.0. This technique incorporates a unique capability of predicting the off-design performance of advanced or supercritical airfoil sections. The buffet onset limit may also be estimated. The method is applicable to wind tunnel models as well as to full scale configurations. This technique has been converted into a computer code for use on the IBM 360 and CDC 7600 computer facilities at NASA AMES. Results obtained using this method to predict known aircraft characteristics are good and agreement can be obtained within a degree of accuracy judged to be sufficient for the initial processes of preliminary design.

  10. Electron cloud buildup studies for the LHC

    CERN Document Server

    AUTHOR|(CDS)2160803; Boine-Frankenheim, Oliver

    Electron clouds can develop in accelerators operating with positively charged particles. The con- sequences of e-cloud related effects are very important for the operation of the Large Hadron Collider (LHC) at CERN, and for the design of future accelerators including the LHC luminosity upgrade (HL-LHC). High electron densities are generated by an interaction between the beam and the confining chamber. Primary electrons, that can be generated through various mecha- nisms, are accelerated by the beam and impinge on the chamber walls, thereby extracting more electrons from the material. Furthermore they also deposit their kinetic energy in the process, which has to be compensated by the cooling system. Especially in cryogenic environments, as it is the case for a large part of the LHC, high heat loads can pose a serious problem. In order to improve the understanding of the electron cloud, simulation studies are performed with the code PyECLOUD, developed at CERN. The work of the first half of the project is desc...

  11. Polysaccharide Thin Films – Buildup and Hydration

    Science.gov (United States)

    Plating, painting and the application of enamel are common anti-corrosion treatments by providing a barrier of resistant material between the damaging environment and the structural material. Coatings start failing rapidly if scratched or damaged because “pitting” occurs at high rates in cracks or p...

  12. Essential role of the electroneutral Na+–HCO3− cotransporter NBCn1 in murine duodenal acid–base balance and colonic mucus layer build-up in vivo

    Science.gov (United States)

    Singh, Anurag Kumar; Xia, Weiliang; Riederer, Brigitte; Juric, Marina; Li, Junhua; Zheng, Wen; Cinar, Ayhan; Xiao, Fang; Bachmann, Oliver; Song, Penghong; Praetorius, Jeppe; Aalkjaer, Christian; Seidler, Ursula

    2013-01-01

    Duodenal epithelial cells need efficient defence strategies during gastric acidification of the lumen, while colonic mucosa counteracts damage by pathogens by building up a bacteria-free adherent mucus layer. Transport of HCO3− is considered crucial for duodenal defence against acid as well as for mucus release and expansion, but the transport pathways involved are incompletely understood. This study investigated the significance of the electroneutral Na+–HCO3− cotransporter NBCn1 for duodenal defence against acid and colonic mucus release. NBCn1 was localized to the basolateral membrane of duodenal villous enterocytes and of colonic crypt cells, with predominant expression in goblet cells. Duodenal villous enterocyte intracellular pH was studied before and during a luminal acid load by two-photon microscopy in exteriorized, vascularly perfused, indicator (SNARF-1 AM)-loaded duodenum of isoflurane-anaesthetized, systemic acid–base-controlled mice. Acid-induced HCO3− secretion was measured in vivo by single-pass perfusion and pH-stat titration. After a luminal acid load, NBCn1-deficient duodenocytes were unable to recover rapidly from intracellular acidification and could not respond adequately with protective HCO3− secretion. In the colon, build-up of the mucus layer was delayed, and a decreased thickness of the adherent mucus layer was observed, suggesting that basolateral HCO3− uptake is essential for optimal release of mucus. The electroneutral Na+–HCO3− cotransporter NBCn1 displays a differential cellular distribution in the murine intestine and is essential for HCO3−-dependent mucosal protective functions, such as recovery of intracellular pH and HCO3− secretion in the duodenum and secretion of mucus in the colon. PMID:23401617

  13. Methods of increasing the performance of radionuclide generators used in nuclear medicine: daughter nuclide build-up optimisation, elution-purification-concentration integration, and effective control of radionuclidic purity.

    Science.gov (United States)

    Le, Van So; Do, Zoe Phuc-Hien; Le, Minh Khoi; Le, Vicki; Le, Natalie Nha-Truc

    2014-06-10

    Methods of increasing the performance of radionuclide generators used in nuclear medicine radiotherapy and SPECT/PET imaging were developed and detailed for 99Mo/99mTc and 68Ge/68Ga radionuclide generators as the cases. Optimisation methods of the daughter nuclide build-up versus stand-by time and/or specific activity using mean progress functions were developed for increasing the performance of radionuclide generators. As a result of this optimisation, the separation of the daughter nuclide from its parent one should be performed at a defined optimal time to avoid the deterioration in specific activity of the daughter nuclide and wasting stand-by time of the generator, while the daughter nuclide yield is maintained to a reasonably high extent. A new characteristic parameter of the formation-decay kinetics of parent/daughter nuclide system was found and effectively used in the practice of the generator production and utilisation. A method of "early elution schedule" was also developed for increasing the daughter nuclide production yield and specific radioactivity, thus saving the cost of the generator and improving the quality of the daughter radionuclide solution. These newly developed optimisation methods in combination with an integrated elution-purification-concentration system of radionuclide generators recently developed is the most suitable way to operate the generator effectively on the basis of economic use and improvement of purposely suitable quality and specific activity of the produced daughter radionuclides. All these features benefit the economic use of the generator, the improved quality of labelling/scan, and the lowered cost of nuclear medicine procedure. Besides, a new method of quality control protocol set-up for post-delivery test of radionuclidic purity has been developed based on the relationship between gamma ray spectrometric detection limit, required limit of impure radionuclide activity and its measurement certainty with respect to

  14. Light wheel buildup using a backward surface mode

    OpenAIRE

    Polles, Rémi; Moreau, Antoine; Granet, Gérard

    2010-01-01

    3 pages; International audience; When a guided mode is excited in a dielectric slab coupled to a backward surface wave at the interface between a dielectric and a left-handed medium, light is confined in the structure : this is a light wheel. Complex plane analysis of the dispersion relation and coupled-mode formalism give a deep insight into the physics of this phenomenon (lateral confinement and the presence of a dark zone).

  15. Light wheel buildup using a backward surface mode.

    Science.gov (United States)

    Pollès, Rémi; Moreau, Antoine; Granet, Gérard

    2010-10-01

    When a guided mode is excited in a dielectric slab coupled to a backward surface wave at the interface between a dielectric and a left-handed medium, light is confined in the structure: this is a light wheel. Complex plane analysis of the dispersion relation and coupled-mode formalism give deep insight into the physics of this phenomenon (lateral confinement and the presence of a dark zone).

  16. The Build-Up of Diversity in Complex Ecosystems

    CERN Document Server

    Tacchella, Andrea; Gabrielli, Andrea; Pietronero, Luciano

    2016-01-01

    Diversity is a fundamental feature of ecosystems, even when the concept of ecosystem is extended to sociology or economics. Diversity can be intended as the count of different items, animals, or, more generally, interactions. There are two classes of stylized facts that emerge when diversity is taken into account. The first are Diversity explosions: evolutionary radiations in biology, or the process of escaping 'Poverty Traps' in economics are two well known examples. The second is nestedness: entities with a very diverse set of interactions are the only ones that interact with more specialized ones. In a single sentence: specialists interact with generalists. Nestedness is observed in a variety of bipartite networks of interactions: Biogeographic, macroeconomic and mutualistic to name a few. This indicates that entities diversify following a pattern. Since they appear in such very different systems, these two stylized facts point out that the build up of diversity is driven by a fundamental probabilistic mec...

  17. Time-dependent correlation buildup in spherical Yukawa balls

    Science.gov (United States)

    Kaehlert, Hanno; Bonitz, Michael

    2009-11-01

    In recent years it has become possible to create 3D dust crystals in experiments [1], where the particles arrange on concentric spherical shells. Compared to confined ions the interaction between the dust particles is screened, which has been shown to affect the shell occupation of the ground state [2], and the probability of metastable states [3,4]. Here we study dynamical processes in a trapped Yukawa plasma by means of Langevin dynamics simulations, which fully include the Coulomb correlations, the confinement and friction with the neutral gas. By cooling a weakly correlated initial state towards the strong coupling regime, the formation of concentric shells is observed. While in systems with Coulomb interaction the shells clearly emerge at the cluster boundary, they appear almost simultaneously for sufficiently large screening. Monte Carlo simulations are used to show that the sequence, in which radial order is established, is determined by the confinement potential.[4pt] [1] O. Arp, D. Block, A. Piel, and A. Melzer, PRL 93, 165004 (2004)[0pt] [2] H. Baumgartner et al., New J. Phys. 10, 093019 (2008)[0pt] [3] D. Block et al., Phys. Plasmas 15, 040701 (2008)[0pt] [4] H. K"ahlert et al., Phys. Rev. E 78, 036408 (2008)

  18. Investigation of Air Force Build-Up Roofing Tolerances.

    Science.gov (United States)

    1986-09-01

    outliers was not provided with sample test results. Ladislav Jerga , from Roof Systems Laboratory of Southfield Michigan, has conducted similar statistical...analysis on built-up roofing variances. Some of the research conducted by Ladislav Jerga has been made available (39). It is included herein for...More to Built-Up Roofing Asphalt Than Black and Sticky," Western Roofing, 4: 6-7 (February 1981). Jerga , Ladislav, Director. Personal Correspondence

  19. Pilot studies on discolouration loose deposits' build-up

    NARCIS (Netherlands)

    Poças, Ana; Rebola, Nazaré; Rodrigues, Sérgio; Benoliel, Maria João; Rietveld, Luuk; Vreeburg, Jan; Menaia, José

    2015-01-01

    Tap water discolouration occurs due to resuspension of loose deposits (LD) that accumulate in drinking water distribution systems. Strategies for discolouration control involve network pipe cleaning and replacement of cast-iron pipes. However, the sole application of such measures is not

  20. Photoelectrons and Multipacting in the LHC: Electron Cloud Buildup

    Energy Technology Data Exchange (ETDEWEB)

    Stupakov, Gennady V.

    2003-08-15

    A simple quasi-analytic model is developed for the dynamics of electron cloud generated by synchrotron radiation of the beam in the LHC beam pipe. The model allows to obtain a multipacting condition for the LHC parameters, takes into account the space charge effect and predicts an equilibrium density of the electrons. Based on this model, we find the electron lifetime and estimate the energy deposition of the electron cloud to the wall. We also estimate the emittance growth of the beam due to random fluctuations of the electric field of the cloud and find the growth rate of the beam instability caused by the electrons.

  1. Quality of USMC Officers: Buildup Vs. Reduction in Forces

    Science.gov (United States)

    2016-03-01

    the force outside of the gradual approach in Title 10. Essentially, the CD board is a promotion- style board that reviews eligible officers and...PFT), swim qualifications, rifle scores, the combat fitness test (CFT), and so forth. These input measures are used to predict career designation...officers have completed RCLF due to lack of time in the system with the new requirement. 22 Swim qualifications underwent a revision during the

  2. Resistência à remoção por tração de coroas totais metálicas cimentadas em dentes com e sem reconstrução coronária Tensile strength of metal crowns cemented on dental and buildup surfaces

    Directory of Open Access Journals (Sweden)

    Eduardo Batista FRANCO

    1999-12-01

    C, 37°C and 55°C, and later subjected to tensile tests in a Universal Kratos testing machine. The results obtained were submitted to ANOVA, showing statistically significant differences (5% between the distinct conditions studied. Regarding the teeth without reconstruction, we verified improved results of Ketac-Cem when using polyacrylic acid. The teeth reconstructed with Vitremer did not show significant statistical difference between the two cementing agents. The reconstruction of teeth buildup surfaces did not hinder the retentiveness of the metal crowns.

  3. Operation New Arrivals. Phase I - The Buildup, 27 April 1975 - 23 May 1975. Part I

    Science.gov (United States)

    1975-07-01

    10 July I’-^S AUTC Office of History bglin Air l-’orcc Base, Florida iv *i(«l^w".ir^W J«’^’ uHt ’"i"’’**1,,H’ ’■"* .-^-■iVri.^^,,, ^^:..^.«l...FOLLOWI^C ADDITIONAL ITEMS ARE ßEING USED, CONSUMPTION 0 AT A NOT AVAILABLE. FLOIJR PUWDERPO MILK CANNED PEACHES SUGAR TOMATO SOUP SOY SAUCE

  4. The Hierarchical Build-Up of Massive Galaxies And the Intracluster Light Since z=1

    Energy Technology Data Exchange (ETDEWEB)

    Conroy, Charlie; /Princeton U.; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC; Kravtsov, Andrey V.; /Chicago U., Astron. Astrophys. Ctr. /Chicago U., EFI

    2007-03-19

    We use a set of simulation-based models for the dissipationless evolution of galaxies since z = 1 to constrain the fate of accreted satellites embedded in dark matter subhalos. These models assign stellar mass to dark matter halos at z = 1 by relating the observed galaxy stellar mass function (GSMF) to the halo+subhalo mass function monotonically. The evolution of the stellar mass content is then followed using halo merger trees extracted from N-body simulations. Our models are differentiated only in the fate assigned to satellite galaxies once subhalos, within which satellites are embedded, disrupt. These models are confronted with the observed evolution in the massive end of the GSMF, the z {approx} 0 brightest cluster galaxy (BCG)-cluster mass relation, and the combined BCG and intracluster light (ICL) luminosity distribution--all observables expected to evolve approximately dissipationlessly since z = 1. The combined observational constraints favor a model in which the vast majority ({approx}> 80%) of satellite stars from disrupted subhalos go into the ICL (operationally defined here as light below a surface brightness cut of {mu}{sub i} {approx} 23mag arcsec{sup -2}). Conversely, models that leave behind a significant population of satellite galaxies once the subhalo has disrupted are strongly disfavored, as are models that put a significant fraction of satellite stars into the BCG. Our results show that observations of the ICL provide useful and unique constraints on models of galaxy merging and the dissipationless evolution of galaxies in groups and clusters.

  5. Depth Profiling (ICP-MS Study of Toxic Metal Buildup in Concrete Matrices: Potential Environmental Impact

    Directory of Open Access Journals (Sweden)

    Ghada Bassioni

    2010-10-01

    Full Text Available This paper explores the potential of concrete material to accumulate toxic trace elements using ablative laser technology (ICP-MS. Concrete existing in offshore structures submerged in seawater acts as a sink for hazardous metals, which could be gradually released into the ocean creating pollution and anoxic conditions for marine life. Ablative laser technology is a valuable tool for depth profiling concrete to evaluate the distribution of toxic metals and locate internal areas where such metals accumulate. Upon rapid degradation of concrete these “hotspots” could be suddenly released, thus posing a distinct threat to aquatic life. Our work simulated offshore drilling conditions by immersing concrete blocks in seawater and investigating accumulated toxic trace metals (As, Be, Cd, Hg, Os, Pb in cored samples by laser ablation. The experimental results showed distinct inhomogeneity in metal distribution. The data suggest that conditions within the concrete structure are favorable for random metal accumulation at certain points. The exact mechanism for this behavior is not clear at this stage and has considerable scope for extended research including modeling and remedial studies.

  6. Inversion Build-Up and Cold-Air Outflow in a Small Alpine Sinkhole

    Science.gov (United States)

    Lehner, Manuela; Whiteman, C. David; Dorninger, Manfred

    2017-06-01

    Semi-idealized model simulations are made of the nocturnal cold-air pool development in the approximately 1-km wide and 100-200-m deep Grünloch basin, Austria. The simulations show qualitatively good agreement with vertical temperature and wind profiles and surface measurements collected during a meteorological field expedition. A two-layer stable atmosphere forms in the basin, with a very strong inversion in the lowest part, below the approximate height of the lowest gap in the surrounding orography. The upper part of the stable layer is less strongly stratified and extends to the approximate height of the second-lowest gap. The basin atmosphere cools most strongly during the first few hours of the night, after which temperatures decrease only slowly. An outflow of air forms through the lowest gap in the surrounding orography. The outflow connects with a weak inflow of air through a gap on the opposite sidewall, forming a vertically and horizontally confined jet over the basin. Basin cooling shows strong sensitivity to surface-layer characteristics, highlighting the large impact of variations in vegetation and soil cover on cold-air pool development, as well as the importance of surface-layer parametrization in numerical simulations of cold-air-pool development.

  7. The build-up and characterization of nuclear burn-up wave in a fast ...

    Indian Academy of Sciences (India)

    K V Anoop

    2018-02-07

    Feb 7, 2018 ... However, there are concerns relating to the nuclear safety, waste management and nuclear weapons proliferation associated with this source. Therefore, new reactor con- cepts are being studied internationally with emphasis on maximizing the resource utilization, intrinsic safety with self-regulation and ...

  8. Problems of Gas Pressure Build-up in Casing String of UGS and Gas Wells

    Directory of Open Access Journals (Sweden)

    Peter Sovius

    2006-10-01

    Full Text Available This paper consists of three basic parts. The opening part is a brief description of problems associated with the secondary untightness of UGS wells (Underground Gas Storages and gas wells generally.The main part of the paper is composed of some cases that we have met in our company. Solution proposals of various cases are also supplied in this part. Separate problem situations are described in terms of finding out an untight point and also a testing result and consequential removing of untightness.The conclusion includes knowledge summary that were taken by solution of complicatedsituations connected with well non-hermeticity.

  9. Military Buildup on Guam: Costs and Challenges in Meeting Construction Timelines

    Science.gov (United States)

    2011-06-27

    of a site for the transient aircraft carrier berth within Apra Harbor, and (3) the potential deployment of an air and missile defense task force on...capability Proposed transient aircraft carrier berth Naval Base Guam Apra Harbor Former FAA parcel (for Marine Corps main cantonment) Navy...125,500,000 rescission in Pub. L. No. 112-10 (2011). Apra Harbor Wharf Improvements 127,033,000 127,033,000 0 No savings realized. Total

  10. A Build-Up Interior Method for Linear Programming: Affine Scaling Form

    Science.gov (United States)

    1990-02-01

    would imply b = 0 contrary to (AO)). Also note that 0 < IID II = (x ) TD ’ Vx = (AAD - 2 )D 2 (D - 2A AT ) = A(AD-2A T )AT = A(AD- 2 AT)(AD- 2 AT)-b = Ab...if 2N = 0. The nondegeneracy assumption (A4) also states that I2,l>O for jEB . (7.1) By definition, the dual basic solution complementary to 2 is (., i...Let ,o = (1/2)min(’i EB, eN). There exists a to such that for all t > to: ts.<fo jEB and u;>eo jEN. Z .>to jEB and z.<EO jeN. z’/ut. >1 jEB and z4/t

  11. Simulated Internal Storage Buildup, Release, and Runoff from Greenland Ice Sheet at Kangerlussuaq, West Greenland

    NARCIS (Netherlands)

    Mernild, S. H.; Liston, G. E.; van den Broeke, M.R.|info:eu-repo/dai/nl/073765643

    2012-01-01

    This study focused on simulated glacier surface conditions (simulated Surface Melt and liquid Precipitation available for supra-, en-, sub-, and proglacial flow processes [after vertical percolation and potential storage within the snowpack] [henceforth SMP]), internal water storage and release, and

  12. Carbohydrate control over carotenoid build-up is conditional on fruit ontogeny in clementine fruits.

    Science.gov (United States)

    Poiroux-Gonord, Florine; Fanciullino, Anne-Laure; Poggi, Isabelle; Urban, Laurent

    2013-04-01

    The final contents of primary and secondary metabolites of the ripe fruit depend on metabolic processes that are tightly regulated during fruit ontogeny. Carbohydrate supply during fruit development is known to influence these processes but, with respect to secondary metabolites, we do not really know whether this influence is direct or indirect. Here, we hypothesized that the sensitivity of clementine fruit metabolism to carbohydrate supply was conditional on fruit developmental stage. We applied treatments increasing fruit load reversibly or irreversibly at three key stages of clementine (Citrus clementina Hort. ex Tan.) fruit development: early after cell division, at the onset of fruit coloration (color break) and near maturity. The highest fruit load obtained by early defoliation (irreversible) had the highest impact on fruit growth, maturity and metabolism, followed by the highest fruit load obtained by early shading (reversible). Final fruit size decreased by 21 and 18% in these early irreversible and reversible treatments, respectively. Soluble sugars decreased by 18% in the early irreversible treatment, whereas organic acids increased by 46 and 29% in these early irreversible and reversible treatments, respectively. Interestingly, total carotenoids increased by 50 and 18%, respectively. Changes in leaf starch content and photosynthesis supported that these early treatments triggered a carbon starvation in the young fruits, with irreversible effects. Furthermore, our observations on the early treatments challenge the common view that carbohydrate supply influences positively carotenoid accumulation in fruits. We propose that early carbon starvation irreversibly promotes carotenoid accumulation. Copyright © Physiologia Plantarum 2012.

  13. SU-F-BRCD-03: Dose Calculation of Electron Therapy Using Improved Lateral Buildup Ratio Method.

    Science.gov (United States)

    Gebreamlak, W; Tedeschi, D; Alkhatib, H

    2012-06-01

    To calculate the percentage depth dose of any irregular shape electron beam using modified lateral build-up-ratio method. Percentage depth dose (PDD) curves were measured using 6, 9, 12, and 15MeV electron beam energies for applicator cone sizes of 6×6, 10×10, 14×14, and 14×14cm2 . Circular cutouts for each cone were prepared from 2.0cm diameter to the maximum possible size for each cone. In addition, three irregular cutouts were prepared. The scanning was done using a water tank and two diodes - one for the signal and the other a stationary reference outside the tank. The water surface was determined by scanning the signal diode slowly from water to air and by noting the sharp change of the percentage depth dose curve at the water/air interface. The lateral build-up-ratio (LBR) for each circular cutout was calculated from the measured PDD curve using the open field of the 14×14 cm2 cone as the reference field. Using the LBR values and the radius of the circular cutouts, the corresponding lateral spread parameter (sigma) of the electron shower was calculated. Unlike the commonly accepted assumption that sigma is independent of cutout size, it is shown that the sigma value increases linearly with circular cutout size. Using this characteristic of sigma, the PDD curves of irregularly shaped cutouts were calculated. Finally, the calculated PDD curves were compared with measured PDD curves. In this research, it is shown that sigma increases with cutout size. For radius of circular cutout sizes up to the equilibrium range of the electron beam, the increase of sigma with the cutout size is linear. The percentage difference of the calculated PDD from the measured PDD for irregularly shaped cutouts was under 1.0%. Similar Result was obtained for four electron beam energies (6, 9, 12, and 15MeV). © 2012 American Association of Physicists in Medicine.

  14. Radiation damage buildup and dislocation evolution in Ni and equiatomic multicomponent Ni-based alloys

    Science.gov (United States)

    Levo, E.; Granberg, F.; Fridlund, C.; Nordlund, K.; Djurabekova, F.

    2017-07-01

    Single-phase multicomponent alloys of equal atomic concentrations (;equiatomic;) have proven to exhibit promising mechanical and corrosion resistance properties, that are sought after in materials intended for use in hazardous environments like next-generation nuclear reactors. In this article, we investigate the damage production and dislocation mobility by simulating irradiation of elemental Ni and the alloys NiCo, NiCoCr, NiCoFe and NiFe, to assess the effect of elemental composition. We compare the defect production and the evolution of dislocation networks in the simulation cells of two different sizes, for all five studied materials. We find that the trends in defect evolution are in good agreement between the different cell sizes. The damage is generally reduced with increased alloy complexity, and the dislocation evolution is specific to each material, depending on its complexity. We show that increasing complexity of the alloys does not always lead to decreased susceptibility to damage accumulation under irradiation. We show that, for instance, the NiCo alloy behaves very similarly to Ni, while presence of Fe or Cr in the alloy even as a third component reduces the saturated level of damage substantially. Moreover, we linked the defect evolution with the dislocation transformations in the alloys. Sudden drops in defect number and large defect fluctuations from the continuous irradiation can be explained from the dislocation activity.

  15. Radiation damage buildup by athermal defect reactions in nickel and concentrated nickel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou, People' s Republic of China; Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland; Nordlund, K. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland; National Research Nuclear University MEPhI, Moscow, Russia; Djurabekova, F. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland; National Research Nuclear University MEPhI, Moscow, Russia; Granberg, F. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland; Zhang, Y. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Wang, T. S. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou, People' s Republic of China

    2017-03-09

    We develop a new method using binary collision approximation simulating the Rutherford backscattering spectrometry in channeling conditions (RBS/C) from molecular dynamics atom coordinates of irradiated cells. The approach allows comparing experimental and simulated RBS/C signals as a function of depth without fitting parameters. The simulated RBS/C spectra of irradiated Ni and concentrated solid solution alloys (CSAs, NiFe and NiCoCr) show a good agreement with the experimental results. The good agreement indicates the damage evolution under damage overlap conditions in Ni and CSAs at room temperature is dominated by defect recombination and migration induced by irradiation rather than activated thermally.

  16. A probabilistic approach on residual strength and damage buildup of high-performance fibers

    NARCIS (Netherlands)

    Knoester, Henk; Hulshof, Joost; Meester, Ronald

    2017-01-01

    An elementary, probabilistic model for fiber failure, developed by Coleman in the fifties of the last century, predicts a Weibull distributed time-to-failure for fibers subject to a constant load. This has been experimentally confirmed, not only for fibers but for load-bearing products in general.

  17. Effect of feeding rate and ammonia build-up on growth performance ...

    African Journals Online (AJOL)

    -up on growth performance of Clarias gariepinus juveniles in the Wet Laboratory, Department of Fisheries and Aquaculture, Ebonyi State University, Abakaliki, Ebonyi State. Completely Randomized Design was used; each treatment was ...

  18. Design of Instrumentation Suitable for the Investigation of Charge Buildup Phenomena at Synchronous Orbit.

    Science.gov (United States)

    1979-10-01

    plates and other surfaces, while the cylindrical plates are ser- rated :nd blackened to reduce the detection of scattered solar UV. The SEM s have +500V...and this contributes counts from solar UV, adding further to SEM de- gradation in those ESA s. The general ESA design thus includes capabilities to...may be used when the RSPD is on the satellite. Both pieces of ground support equipment are completely self-contained. Each is packaged in a suitcase

  19. Characterization and Quantification of Deposits Buildup and Removal in Biomass Suspension-Fired Boilers

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

    2010-01-01

    Utilization of biomass as wood or straw in large suspension­fired boilers is an efficient method to reduce the use of fossil fuels consumption and to reduce the net CO2 formation. However, the presence of chlorine and alkali metals in biomass (straw) generate ash with a low melting point and induce...... characteristics, and deposit removal have been investigated. The final deposit mass signal after a residence time of 3 to 5 days region was 1041, 1475, 1520 and 1670 g/m2 for 35, 65, 80 and 100% straw share respectively in the superheater region (flue gas temperature, 800­900 oC), while the mass uptake was very...... small in the tube bank region (flue gas temperature, 550­605 oC) during pure wood­firing. It was found that during suspension­firing of pure straw at low boiler load, the overall weight uptake is comparable with grate­firing, even though the amount of fly ash generated was significantly higher during...

  20. Design, build-up and optimization of a fast quenching device for polymeric thin film

    Science.gov (United States)

    Montesanto, S.; Mannella, G. A.; La Carrubba, V.; Brucato, V.

    2014-05-01

    In this work an innovative apparatus for the characterization of polymer solidification under very high cooling rates (up to thousand of K/s) is described, according to the continuous cooling transformation approach adopted in metallurgy for studying structure development in metals. The proposed model experiment is addressed to design a method for the characterization of non-isothermal solidification behaviour, encompassing typical cooling conditions of polymer processing. Only temperature history determines the structure formed, as melt solidification takes place in quiescent conditions. With respect to the device previously developed by the authors [1, 3] the present equipment presents the following features: - reduced size (30*30*20 cm); - higher heating rates, by using two electrical resistances supported on ceramic plates; - higher cooling rates, carried out through water sprays at very high pressures (120 bar); - thermal insulation of the sample from the sample holder via the application of two wave springs; - automatic control and synchronization of the whole sequence of operations: transfer of the sample from the melting (heating) zone to the cooling (spray) chamber via rotation (it was via sliding in the previous version); - very high heat transfer coefficients, up to 7*105 W/m2K.

  1. One-pot build-up procedure for the synthesis of variously substituted purine derivatives

    Czech Academy of Sciences Publication Activity Database

    Dejmek, Milan; Kovačková, Soňa; Zborníková, Eva; Hřebabecký, Hubert; Šála, Michal; Dračínský, Martin; Nencka, Radim

    2012-01-01

    Roč. 2, č. 17 (2012), s. 6970-6980 ISSN 2046-2069 R&D Projects: GA MV VG20102015046 Institutional support: RVO:61388963 Keywords : purines * heterocycles * adenine * guanine Subject RIV: CC - Organic Chemistry Impact factor: 2.562, year: 2012

  2. Utilization of photovoltaic panels in urban build-up areas – grid on

    Directory of Open Access Journals (Sweden)

    Rybár Radim

    2001-12-01

    Full Text Available Photovoltaic systems belong to the most perspective alternative sources of energy. We expect that during a relatively short period of time, the photovoltaic systems will slowly cover 5 to 10 % of the whole consumption of the electricity. One of the conditions of integration to European Community is the rising of the part of alternative sources in the production of energy. Besides another technologies, it’s also possible to reach it with an installation of the photovoltaic systems in already-existed building-up area. The photovoltaic systems “Grid on” are used especially in places with the advanced net of electric lines – in big cities. The invertors developed especially for the photovoltaic systems "Grid on" have the effeciency higher than 90 % and they are absolute safe against the bias voltage.From the entire number of days of an year in Slovakia the sun shines from 1300 to 2200 hours, in Košice it’s 2100 hours. An average amount of energy falling down by one day is 3,3 kW.h.m-2. An average effective power of one m2 of the photovoltaic panels is 110 W.m-2 of the standard illuminance 1000 W.m-2 and the solar spectrum AM 1,5. Annually it’s possible to make from the photovoltaic panel (1 m2 120,45 kW.h. Average amount of the solar energy shape to the south-orient area in Košice is 101,5 kW.h.m-2. In Košice is an ideal inclination of the absorption area of the photovoltaic panels from horizontal plains from 58° to 65° for the year-around operation. At optimal conditions it’s possible by integrating photovoltaic panels with the construction of the balcony barrier from one block of flats about 10 MW.h per year. If we utilise the all areas applicable for the installation of photovoltaic panels (building exteriors, roofs, shady component,.., we able to cast about a few multiple of these value just for one block of flat.Today, the cost of the photovoltaic systems is many times higher than the cost of the electric energy. But the cost consequently a new technology of production of the primary materials is allways falling.

  3. NARMER-1: a photon point-kernel code with build-up factors

    Science.gov (United States)

    Visonneau, Thierry; Pangault, Laurence; Malouch, Fadhel; Malvagi, Fausto; Dolci, Florence

    2017-09-01

    This paper presents an overview of NARMER-1, the new generation of photon point-kernel code developed by the Reactor Studies and Applied Mathematics Unit (SERMA) at CEA Saclay Center. After a short introduction giving some history points and the current context of development of the code, the paper exposes the principles implemented in the calculation, the physical quantities computed and surveys the generic features: programming language, computer platforms, geometry package, sources description, etc. Moreover, specific and recent features are also detailed: exclusion sphere, tetrahedral meshes, parallel operations. Then some points about verification and validation are presented. Finally we present some tools that can help the user for operations like visualization and pre-treatment.

  4. QELBY®-Induced Enhancement of Exclusion Zone Buildup and Seed Germination

    Directory of Open Access Journals (Sweden)

    Abha Sharma

    2017-01-01

    Full Text Available A hydrophilic powder, QELBY, from the feldspar family of clay minerals was investigated for its ability to form structured or exclusion-zone (EZ water. We demonstrated microsphere-free zones around different fractions of the QELBY powder or its hydrated pellet. Averaging approximately 100 μm, these zones grew to a size similar to that formed in the vicinity of the Nafion standard. In the case of silica (control, only occasional microsphere-free zones of about 70 μm were found. Further, studies to investigate QELBY’s energizing effect on germination and early sapling growth in brown chickpea seeds showed at least a 2-3-fold increase in root length and/or formation of shoots. This was seen in seeds bathed in QELBY supernatants or surrounded by QELBY powder outside the vials containing the seeds. This indirect effect was observed whether the QELBY was dry or hydrated.

  5. Transmission fidelity is the key to the build-up of cumulative culture

    Science.gov (United States)

    Lewis, Hannah M.; Laland, Kevin N.

    2012-01-01

    Many animals have socially transmitted behavioural traditions, but human culture appears unique in that it is cumulative, i.e. human cultural traits increase in diversity and complexity over time. It is often suggested that high-fidelity cultural transmission is necessary for cumulative culture to occur through refinement, a process known as ‘ratcheting’, but this hypothesis has never been formally evaluated. We discuss processes of information transmission and loss of traits from a cognitive viewpoint alongside other cultural processes of novel invention (generation of entirely new traits), modification (refinement of existing traits) and combination (bringing together two established traits to generate a new trait). We develop a simple cultural transmission model that does not assume major evolutionary changes (e.g. in brain architecture) and show that small changes in the fidelity with which information is passed between individuals can lead to cumulative culture. In comparison, modification and combination have a lesser influence on, and novel invention appears unimportant to, the ratcheting process. Our findings support the idea that high-fidelity transmission is the key driver of human cumulative culture, and that progress in cumulative culture depends more on trait combination than novel invention or trait modification. PMID:22734060

  6. Internal filtration and external filter cake build-up in sandstones

    NARCIS (Netherlands)

    Al-Abduwani, F.A.H.

    2005-01-01

    Water injection is an integral constituent of most field development scenarios. This injection may take place for secondary recovery and pressure maintenance such as sea water injection. Alternatively, it may take place as a waste water disposal method as in the case of produced water re-injection.

  7. Effect of the LHC Beam Screen Baffle on the Electron Cloud Buildup

    CERN Document Server

    Romano, Annalisa; Li, Kevin; Rumolo, Giovanni

    2016-01-01

    Electron Cloud (EC) has been identified as one of the major intensity-limiting factors in the CERN Large Hadron Collider (LHC). Due to the EC, an additional heat load is deposited on the perforated LHC beam screen, for which only a small cooling capacity is available. In order to preserve the superconducting state of the magnets, pumping slots shields were added on the outer side of the beam screens. In the framework of the design of the beam screens of the new HL-LHC triplets, the impact of these shields on the multipacting process was studied with macroparticle simulations. For this purpose multiple new features had to be introduced in the PyECLOUD code. This contribution will describe the implemented simulation model and summarize the outcome of this study.

  8. 3D Facial Effects of a Simulated Dental Build-up.

    Science.gov (United States)

    Sterenborg, Bernadette A M M; Maal, Thomas J J; Vreeken, Rinaldo D; Loomans, Bas A C; Huysmans, Marie-Charlotte D N J M

    2016-11-12

    The purpose of this study was to evaluate the 3D-stereophotogrammetry technique to detect differences in facial appearance after a simulated rehabilitation. Eleven volunteers without tooth wear participated. A 3D-stereophotograph was taken in five different situations: resting position, teeth in occlusion, and teeth in occlusion with a 1 mm-, 3 mm- or 5 mm resin block between the first molars. Cephalometric measurements were performed on the 3D-stereophotographs using the software program Maxilim® (Medicim NV Mechelen, Belgium). Four anatomical parameters were analyzed: (1) Subnasale-Gnathion, (2) Subnasale-Stomion, (3) Stomion-Gnathion, and (4) Masseter right-Masseter left. A paired Student's T-test was applied to detect significant differences (p teeth in occlusion, 1 mm-, 3 mm-, and 5 mm block (p 3D-stereophotograph imaging technology, it was possible to detect changes in facial appearance after an artificial increase of vertical dimension of occlusion. This finding implies that reconstruction of loss of tooth substance may cause a visible change in facial appearance of the patient. This study reveals a new 3D imaging technique that may be used for a better and more comprehensive treatment planning in patients with severe tooth wear. (J Esthet Restor Dent 28:397-404, 2016). © 2016 Wiley Periodicals, Inc.

  9. Modeling Fungal Melanin Buildup: Biomimetic Polymerization of 1,8-Dihydroxynaphthalene Mapped by Mass Spectrometry.

    Science.gov (United States)

    Cecchini, Martina Maya; Reale, Samantha; Manini, Paola; d'Ischia, Marco; De Angelis, Francesco

    2017-06-12

    Due to the emerging biomedical relevance and technological potential of fungal melanins, and prompted by the virtual lack of information about their structural arrangement, an optimized synthetic protocol has been devised for a potential structural model of Ascomyces allomelanin through enzyme-catalyzed oxidative polymerization of 1,8-dihydroxynaphthalene (1,8-DHN). Electrospray ionization mass spectrometry (ESI-MS) measurements of freshly synthesized DHN-polymer recorded in the negative ion mode allowed detection of oligomers up to m/z 4000, separated by 158 Da, corresponding to the in-chain DHN-unit. The dominant peaks were assigned to singly-charged distribution, up to 23 repeating units, whereas a doubly charged polymer distribution was also detectable. Chemical derivatization, ultra-performance liquid chromatography (UPLC)-ESI MS, and MS/MS data confirmed that oxidative polymerization of 1,8-DHN proceeds through C-C coupling of the naphthalene rings. The new insights reported here into synthetic 1,8-DHN oligomers/polymers as a mimic of fungal melanins may guide novel interesting advances and applications in the field of biomimetic functional materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Modelling Venting and Pressure Build-up in a 18650 LCO Cell during Thermal Runaway (ABSTRACT)

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian; White, Ralph

    may lead to fires and explosions. To prevent this, it is therefore important to model thermal runaway considering different events such as venting and the pressure development inside the battery cell, which makes the main purpose of this paper. A model consisting of the different decomposition....... By fitting the activation energies, and measuring experimentally the mass of the ejecta during thermal runaway, the model is compared and validated against an extensive experiment performed by Golukbov et al. [1] during oven heating. When analysing the results, it is found that by including the venting......Li-ion batteries are a very popular type of electric storage devices that possess high energy density when compared to the other battery chemistries. Due to this property, when operating under abusive conditions such as high ambient temperature, the batteries can experience thermal runaway, which...

  11. Understanding the build-up of a technological innovation system around hydrogen and fuel cell technologies

    NARCIS (Netherlands)

    Suurs, R.A.A.; Hekkert, M.P.; Smits, R.E.H.M.

    2009-01-01

    This study provides insight into the development of hydrogen and fuel cell technologies in the Netherlands (1980-2007). This is done by applying a Technological Innovation System (TIS) approach. This approach takes the perspective that a technology is shaped by a surrounding network of actors,

  12. Buildup of aerosol precursor gases and sulfur-induced activation of soot in nascent jet aircraft exhaust plumes

    Energy Technology Data Exchange (ETDEWEB)

    Kaercher, B.; Hirschberg, M.M.; Fabian, P. [Muenchen Univ. (Germany). Lehrstuhl fuer Bioklimatologie und Immissionsforschung; Gerz, T. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    Research issues concerning the chemical transformation of exhaust trace gases are summarized. The photochemical evolution of NO{sub x} early in the plume is strongly coupled to plume mixing. Substantial amounts of HNO{sub 3} are generated in nascent plumes even if no NO{sub 2} is emitted. The production of H{sub 2}SO{sub 4} becomes very efficient if part of the fuel sulfur is emitted as SO{sub 3}. Each emitted soot particle can acquire 1-10% by mass fully oxidized sulfur molecules prior to binary homogeneous nucleation, if a few percent of the exhaust SO{sub x} are emitted as SO{sub 3}, indicating an important activation pathway for soot, and leading to a marked enhancement of new aerosol formation and growth rates. (author) 11 refs.

  13. Air Force Basing Strategies in the Western Pacific in Response to Chinese Military Buildup during Fiscal Austerity

    Science.gov (United States)

    2016-02-01

    government facilities on them, as long as they are not already physically occupied. In essence, a massive game of chicken 21 is being played out on...ASEAN partners, and the U.S., that China has no intention of discontinuing their pattern of reclamation and military expansion. This is a chess game and...significantly increase range and loiter capabilities. Andersen Air Force Base in Guam sits just 1400 NM to the East of Clark Air Base. Transit time to a

  14. Russian Build-Up on the Black Sea and Recommendations for U.S.-NATO Counter-Strategy

    Science.gov (United States)

    2017-03-01

    sustainable , and long-term strategy toward the region. Port visits of non-littoral NATO navies, joint exercises, and short-term deployment of forces in the...accessible to foreign invaders to sustain large-scale invasions. Russia was always a land power; it was and still is vulnerable to huge armies accessing...States, the EU, Norway, Canada, and Australia. McDonald’s restaurants closed in Russia, and Moscow threatened Washington with a ban on sales of rocket

  15. Build-up of Red Blood Cells in Refuelling Bar-Tailed Godwits in Relation to Individual Migratory Quality

    NARCIS (Netherlands)

    Piersma, Theunis; Everaarts, Jan M.; Jukema, Joop

    1996-01-01

    We examined hemoglobin concentration, hematocrit and mean cell hemoglobin concentration (MCHbC) in Bar-tailed Godwits Limosa lapponica during the latter half of their staging period in May in the Wadden Sea of The Netherlands. Here they recover from a 4,000-5,000 km long flight from West African

  16. Semi-empirical prediction of moisture build-up in an electronic enclosure using analysis of variance (ANOVA)

    DEFF Research Database (Denmark)

    Shojaee Nasirabadi, Parizad; Conseil, Helene; Mohanty, Sankhya

    2016-01-01

    and temperature are studied. A set of experiments are done based on a fractional factorial design in order to estimate the time constant for moisture transfer into the enclosure by fitting the experimental data to an analytical quasi-steady-state model. According to the statistical analysis, temperature...... and the opening length are found as the most significant factors. Based on analysis of variance of the derived time constants, a semi-empirical regression model is proposed to predict the moisture transfer time constant with an adjusted R2 of 0.98; which demonstrated that the model can be used for estimation...

  17. Endodontic treatment and esthetic management of a primary double tooth with direct composite using silicone buildup guide

    OpenAIRE

    Vinaya Kumar Kulkarni; T Raju Ragavendra; Jeevanand Deshmukh; Amit Vanka; Mahesh Kumar Duddu; Patil, Anand Kumar G.

    2012-01-01

    Gemination and fusion are morphological dental anomalies, characterized by the formation of a clinically wide tooth. Gemination occurs when one tooth bud tries to divide, while fusion occurs if two buds unite. The terms double teeth, double formation, conjoined teeth, geminifusion, vicinifusion and dental twinning are often used to describe fusion and gemination. Double teeth are associated with clinical problems such as poor esthetics, spacing problems and caries susceptibility. Management o...

  18. Signs for secondary buildup of heavy metals in soils at the periphery of Athens International Airport, Greece.

    Science.gov (United States)

    Massas, Ioannis; Gasparatos, Dionisios; Ioannou, Dafni; Kalivas, Dionisios

    2017-10-20

    Emissions from civil airports are similar to those observed in industrial and urban areas. While air pollution and noise levels are regularly monitored and assessed, information on the status of heavy metals in soils close to airport facilities is limited. In this study, we monitored and assessed heavy metal distribution in soils close to Athens International Airport (AIA) in Attica, Greece. Following a grid sampling scenario, topsoil samples were collected from 86 sites at the periphery of AIA and total and available forms of Cu, Zn, Fe, Mn, Ni, Cr, Pb, and Ba concentrations were determined in aqua regia and DTPA soil extracts, respectively. Median concentration values for both metal forms are not considered as particularly high. However, 90th percentile concentration values for some metals are high, indicating soil enrichment. Evaluation of enrichment factor (EF) and availability ratio (AR) values and EFs spatial distribution have led to consistent conclusions of secondary and ongoing metal accumulation in the soils of the studied area. Tessier sequential extraction procedure was applied to 10% of the soil samples and the results showed high potential availability of Pb, Mn, Cu, and Ni, further supporting the continuous metal accumulation in the studied soils.

  19. The Liquid Sustainer Build-up Time Impact on the Emptying Spacecraft Fuel Tank in Free Orbiting Conditions

    Directory of Open Access Journals (Sweden)

    V. B. Sapozhnikov

    2015-01-01

    Full Text Available Trouble-free operation of liquid rocket engines (LRE depends, among other factors, on the nonstop supply of liquid rocket fuel components in the fuel tank feed line with continuous flow.This condition becomes especially relevant for the aerial vehicles (AV in orbital (suborbital environment. With a little filled fuel tanks discontinuity of flow may occur because of pressurizing gas blow-by in the feed line as a result of the funnel generation (with or without vortex formation and so-called phenomenon of dynamic failure of the interface "liquid-gas”.The paper presents a mathematical model of the process of emptying tank initially a little filled and having a reduced level of the gravity acceleration. Using the developed mathematical model a parametric study has been conducted to find how stabilization rate of liquid flow effects on the volume of drained liquid. The computational experiment defines gas blow-by points in the feed line and propellant residuals, depending on the flow rate, physical properties of the fuel components, residual value of the acceleration, and diameter of the feed line.As a result, an effect is discovered that previously has been never mentioned in publications on research of the emptying processes of the aircraft fuel tanks, namely: with abrupt bootstrap of the flow rate a blow-by of gas occurs at the initial stage of emptying tank. In this case, to ensure LRE trouble-free operation there is a need in a special inner-tank device to prevent premature blow-by of pressurizing gas in the tank feed line.

  20. Can playing the computer game "Tetris" reduce the build-up of flashbacks for trauma? A proposal from cognitive science.

    Directory of Open Access Journals (Sweden)

    Emily A Holmes

    Full Text Available BACKGROUND: Flashbacks are the hallmark symptom of Posttraumatic Stress Disorder (PTSD. Although we have successful treatments for full-blown PTSD, early interventions are lacking. We propose the utility of developing a 'cognitive vaccine' to prevent PTSD flashback development following exposure to trauma. Our theory is based on two key findings: 1 Cognitive science suggests that the brain has selective resources with limited capacity; 2 The neurobiology of memory suggests a 6-hr window to disrupt memory consolidation. The rationale for a 'cognitive vaccine' approach is as follows: Trauma flashbacks are sensory-perceptual, visuospatial mental images. Visuospatial cognitive tasks selectively compete for resources required to generate mental images. Thus, a visuospatial computer game (e.g. "Tetris" will interfere with flashbacks. Visuospatial tasks post-trauma, performed within the time window for memory consolidation, will reduce subsequent flashbacks. We predicted that playing "Tetris" half an hour after viewing trauma would reduce flashback frequency over 1-week. METHODOLOGY/PRINCIPAL FINDINGS: The Trauma Film paradigm was used as a well-established experimental analog for Post-traumatic Stress. All participants viewed a traumatic film consisting of scenes of real injury and death followed by a 30-min structured break. Participants were then randomly allocated to either a no-task or visuospatial ("Tetris" condition which they undertook for 10-min. Flashbacks were monitored for 1-week. Results indicated that compared to the no-task condition, the "Tetris" condition produced a significant reduction in flashback frequency over 1-week. Convergent results were found on a clinical measure of PTSD symptomatology at 1-week. Recognition memory between groups did not differ significantly. CONCLUSIONS/SIGNIFICANCE: Playing "Tetris" after viewing traumatic material reduces unwanted, involuntary memory flashbacks to that traumatic film, leaving deliberate memory recall of the event intact. Pathological aspects of human memory in the aftermath of trauma may be malleable using non-invasive, cognitive interventions. This has implications for a novel avenue of preventative treatment development, much-needed as a crisis intervention for the aftermath of traumatic events.

  1. Large-eddy simulation of turbulent dispersion from a localized source in a build-up environment

    Science.gov (United States)

    Wang, Bing-Chen; Saeedi, Mohammad

    2013-11-01

    Turbulent dispersion from a continuous ground-level point-source within an array of 16x16 cubes has been simulated using wall-modelling large-eddy simulations. The major challenges associated with this problem involve obtaining a deeper understanding of the interaction of the dynamically evolving flow structures with the complex boundary conditions, coupling of the momentum and scalar transport processes, and a high Reynolds number tested for an modeled urban atmospheric boundary layer (Re = 12,005 based on the free stream velocity and obstacle height). A fully-parallelized in-house computer code was used for performing the simulation. An advanced dynamic nonlinear model (DNM) and dynamic full linear eddy diffusivity model (DFLTDM) have been used for closure of the filtered momentum and scalar transport equations, respectively. A non-equilibrium thin boundary-layer wall model is applied to all solid surfaces. Inlet boundary conditions based on solid grids have also been investigated in order to generate high turbulence levels typical for an approaching urban atmospheric boundary-layer flow. The predicted results for the flow and concentration field have been thoroughly validated against a set of high-quality water-channel measurement data.

  2. Report on the Second KIMS-CNA Conference: The PLA Navys Build-Up and ROK-USN Cooperation

    Science.gov (United States)

    2009-02-01

    Thailand Presents a Path for Overcoming China’s ‘Malacca Dilemma’), Southern Daily, February 11, 2004 Along with the rapid development of China’s...of Brazil, India, and Malaysia and asserts the right to restrict military activities in their EEZ’s adjacent to their territorial claims to SCS...24 On 12 June 1996, USS Crommelin (FFG-37) conducted a FON assertion against parts of the excessive straight baseline claim in an outbound transit

  3. An Objective Measurement of the Build-Up of Auditory Streaming and of Its Modulation by Attention

    Science.gov (United States)

    Thompson, Sarah K.; Carlyon, Robert P.; Cusack, Rhodri

    2011-01-01

    Three experiments studied auditory streaming using sequences of alternating "ABA" triplets, where "A" and "B" were 50-ms tones differing in frequency by [delta]f semitones and separated by 75-ms gaps. Experiment 1 showed that detection of a short increase in the gap between a B tone and the preceding A tone, imposed on one ABA triplet, was better…

  4. Extreme water loss and abiotic O2 buildup on planets throughout the habitable zones of M dwarfs.

    Science.gov (United States)

    Luger, R; Barnes, R

    2015-02-01

    We show that terrestrial planets in the habitable zones of M dwarfs older than ∼1 Gyr could have been in runaway greenhouses for several hundred million years following their formation due to the star's extended pre-main sequence phase, provided they form with abundant surface water. Such prolonged runaway greenhouses can lead to planetary evolution divergent from that of Earth. During this early runaway phase, photolysis of water vapor and hydrogen/oxygen escape to space can lead to the loss of several Earth oceans of water from planets throughout the habitable zone, regardless of whether the escape is energy-limited or diffusion-limited. We find that the amount of water lost scales with the planet mass, since the diffusion-limited hydrogen escape flux is proportional to the planet surface gravity. In addition to undergoing potential desiccation, planets with inefficient oxygen sinks at the surface may build up hundreds to thousands of bar of abiotically produced O2, resulting in potential false positives for life. The amount of O2 that builds up also scales with the planet mass; we find that O2 builds up at a constant rate that is controlled by diffusion: ∼5 bar/Myr on Earth-mass planets and up to ∼25 bar/Myr on super-Earths. As a result, some recently discovered super-Earths in the habitable zone such as GJ 667Cc could have built up as many as 2000 bar of O2 due to the loss of up to 10 Earth oceans of water. The fate of a given planet strongly depends on the extreme ultraviolet flux, the duration of the runaway regime, the initial water content, and the rate at which oxygen is absorbed by the surface. In general, we find that the initial phase of high luminosity may compromise the habitability of many terrestrial planets orbiting low-mass stars.

  5. The VIMOS Public Extragalactic Redshift Survey (VIPERS). The distinct build-up of dense and normal massive passive galaxies

    Science.gov (United States)

    Gargiulo, A.; Bolzonella, M.; Scodeggio, M.; Krywult, J.; De Lucia, G.; Guzzo, L.; Garilli, B.; Granett, B. R.; de la Torre, S.; Abbas, U.; Adami, C.; Arnouts, S.; Bottini, D.; Cappi, A.; Cucciati, O.; Davidzon, I.; Franzetti, P.; Fritz, A.; Haines, C.; Hawken, A. J.; Iovino, A.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Moutard, T.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Zamorani, G.; Bel, J.; Branchini, E.; Coupon, J.; Ilbert, O.; Moscardini, L.; Peacock, J. A.

    2017-10-01

    We have used the final data from the VIPERS redshift survey to extract an unparalleled sample of more than 2000 massive ℳ≥1011 M⊙ passive galaxies (MPGs) at redshift 0.5≤z≤1.0, based on their NUVrK colours. This has enabled us to investigate how the population of these objects was built up over cosmic time. We find that the evolution of the number density depends on the galaxy mean surface stellar mass density, Σ. In particular, dense (Σ≥2000 M⊙ pc-2) MPGs show a constant comoving number density over this redshift range, whilst this increases by a factor of approximately four for the least dense objects, defined as having Σ programs 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/

  6. From orogenic buildup to extensional unroofing: the evolution of the Adria - Europe collisional zone in the Medvednica Mountains of Croatia

    Science.gov (United States)

    Beniest, Anouk; van Gelder, Inge; Matenco, Liviu; Willingshofer, Ernst; Gruic, Andrea; Tomljenovic, Bruno

    2013-04-01

    Quantifying the kinematics of the Miocene extension in the Pannonian Basin is of critical importance for understanding the evolution of Adria-Europe collision in particular in the transitional zone from the Alps (Adria the upper plate) to the Dinarides (Adria the lower plate). Recent studies have demonstrated that large-scale extensional unroofing and core-complex formation affected the Europe-Adria contact in the Dinarides during Miocene times. The relationship between this extensional exhumation of Adriatic units and the roughly coeval Miocene extension affecting the Alpine-derived units during their E-ward extrusion into the intra-Carpathians ALCAPA block and the formation of the Pannonian basin is still unknown. One key area situated in the transitional zone is the Medvednica Mountains of Croatia, an area that benefits from already existing and extensive petrological and structural studies. The area of the Medvednica Mountains has been targeted by the means of a field kinematic analysis complemented by low-temperature thermochronology, metamorphic petrology and sedimentological observations. The results demonstrate that two units, reflecting distinct Adriatic paleogeographical positions, make up the structural geometry of the mountains. The upper unit contains Paleozoic mostly fine clastic sequence metamorphosed in sub-greenschist facies, overlain by a proximal Adriatic facies consisting of Triassic shallow water carbonates. The lower unit is made up by a volcanic sequence overlain by gradual deepening Triassic carbonates metamorphosed in greenschist facies that bears a strong resemblance to the Triassic break-up volcanism and subsequent sedimentation affecting the distal Adriatic units observed elsewhere in the Jadar-Kopaonik unit of the Dinarides. The strong contrast between the Middle-Upper Triassic facies suggests large scale thrusting during Cretaceous nappe stacking. Subsequently, the studied area has been affected by significant extensional deformation creating the present-day turtleback geometry. This resulted in the formation of brittle normal faults in both units, locally tilted by the uplift of the mountain core, which indicate mostly NE-SW extension. The lower unit is affected by a pervasive deformation characterized by a wide mylonitic shear zone with stretching lineations indicating consistently top-NE to E sense of shear. The present-day structural geometry of the mountains was established during the Pliocene-Quaternary inversion. The exact ages of nappe-stacking and subsequent extensional exhumation will be clarified by the upcoming low-temperature thermochronology and absolute age dating study. However, available results demonstrate that the extensional geometry and sense of shear is typical for the Miocene extensional exhumation and basin formation that affected the Adria-Europe contact elsewhere in the Dinarids, e.g. Kozara-Prosara-Motajica and Fruska Gora extensional structures. By comparing similar extensional features observed in for instance the Rechnitz and Pohorje extensional structures, the combined study potentially demonstrates that the Miocene mechanism of extension and sense of shear is structurally coherent at the scale of the entire Dinaridic and Alpine margins.

  7. Prevention of bottom build-up in reverberatory furnace by injection of reducing gas in converter slag

    Energy Technology Data Exchange (ETDEWEB)

    Saeid, S.; Hassani, H.R. [Sarcheshmeh Copper Complex, Kerman (Iran, Islamic Republic of); Vaghar, R.; Allah Karam, S.R. [Tehran Univ., Kerman (Iran, Islamic Republic of)

    2000-07-01

    A common way to produce copper from sulfide minerals is by converting the molten matte in reverberatory furnaces. In Iran, the process of melting copper matte is carried out by two reverberatory furnaces in the Sarcheshmeh Copper Complex. Efforts are being made to increase efficiency of the furnaces and to eliminate any factors which reduce production. Since the presence of magnetite increases the viscosity of slag, it can prevent complete separation of matte from the slag. For this reason, a study was conducted in which magnetite in a converter slag was reduced by injecting a reducing gas, which was a mixture of propane a butane. Gas blowing was conducted through a lance and a ladle containing 50 kg of molten converter slag for different periods of time at various flow rates. It was determined that the amount of magnetite could be reduced to less than 3-4 per cent with an efficiency of about 85 to 90 per cent. The precipitation of magnetite can also cause a reduction in the life expectancy of the refractories because of the effect of the burner flame and high temperatures. Magnetite can increase the melting point of the slag, resulting in higher energy consumption. It was determined that during the reduction operation, there was a settling time for the reduced copper droplets in the ladle of the slag. The upper layer of the slag could be completely discarded since it contained very little copper. Therefore, a larger volume of the reverberatory furnace remains free for operation. 5 refs., 1 tab., 2 figs.

  8. Ash transformation and deposit build-up during biomass suspension and grate firing: Full-scale experimental studies

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

    2012-01-01

    An attractive option for reducing the net CO2 emissions is to substitute coal with biomass in large power plant boilers. However, the presence of chlorine (Cl) and alkali metals (K, Na) in biomassmay induce large operational problems due to ash deposit formation on the superheater tubes. The aim...... on similar levels. This was observed even though the concentration of fly ash in the flue gas was significantly higher during straw suspension firing. The influence of co-combustion of wood with straw on deposit formation rate, probe heat uptake and deposit characteristicswas also investigated during...

  9. Push-out bond strength between composite core buildup and fiber-reinforced posts after different surface treatments.

    Science.gov (United States)

    Arslan, Hakan; Barutcigil, Cagatay; Yılmaz, Cenk Burak; Ceyhanlı, Kadir Tolga; Topcuoglu, Hüseyin Sinan

    2013-07-01

    The aim of this study was to evaluate the effects of different surface treatments on the pushout bond strength of fiber-reinforced posts to composite resin cores. Twenty-five translucent glass fiber posts were divided into five groups according to surface treatment methods as follows: an untreated control group, a group coated with silicated alumina particles (Co-Jet system, 3M ESPE, St. Paul, MN), and three groups undergoing surface preparation with erbium:yttrium-aluminum-garnet (Er:YAG) laser under three different power settings (150, 300, and 450 mJ at 10 Hz for 60 sec at 100 μs duration). After surface treatment, fiber posts were built up to a dual cure composite resin core. All of the specimens were set and sectioned perpendicularly along the long axis of the post using a saw. Two discs (thickness of 2 mm) were obtained from each post-core sample; finally, each group consisted of 10 samples. For artificial aging, the specimens were stored in water (37°C) for 24 h and subjected to thermal cycling (5000 cycles, 5-55°C, and 30 sec dwell time). Pushout tests were performed using a universal testing machine at a crosshead speed of 0.5 mm/min. The pushout pressure values were measured in MPa and analyzed using one way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) post-hoc test (pFiber post surface images were obtained using a scanning electron microscope (SEM). The bond strength values ranged between 14,949 and 23,879 MPa. The lowest values were observed in the groups treated with the Er:YAG laser at 150 mJ. Irradiation by the Er:YAG laser at 450 mJ affected the bond strength significantly (pfiber-reinforced posts to composite resin cores depending upon the power applied; Co-Jet sandblasting also increased the bond strength.

  10. In-situ buildup of cosmogenic isotopes at the earth`s surface: measurement of erosion rates and exposure times

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, L.K.; Allan, G.L.; Stone, J.O.H.; Evans, J.M.; Cresswell, R.G.; Ophel, T.R. [Australian National Univ., Canberra, ACT (Australia)

    1993-12-31

    Cosmic rays produce a number of nuclides in rocks that can be used to determine the geomorphic history of surfaces. The most useful are the radioactive isotopes {sup 10}Be (t{sub 1/2} = 1.5Ma), {sup 26}Al (0.7Ma) and {sup 36}Cl (0.3Ma). Within the top 2m of the surface, these are produced principally by fast neutrons. At greater depths, production is dominated by the capture of negative muons. Measurements of a single nuclide produced in situ can be used to determine total exposure times or erosion rates. The use of multiple nuclides with different half-lives makes it possible to determine more complex histories, such as exposures interrupted by periods of burial. At the ANU, all three of the isotopes above are being used to study a variety of problems in geomorphology and paleoclimatology, although to date, most of the work has concentrated on {sup 36}Cl. The accumulation of cosmogenic {sup 36}Cl in calcite (CaCO{sub 3}) provides a means of measuring erosion rates on limestone surfaces. Sensitivity is achieved over a wide range of erosion rates due to the high production rate of {sup 36}Cl in calcite (typically greater than 30 atoms/g/yr) and a detection limit of ca. 5000 atoms/g attainable with the ANU AMS system. The method is simplified by the predominance of Ca reactions (principally spallation) over other sources of {sup 36}Cl in calcite, and the ease of sample preparation. This presentation discuss the results of measurements of {sup 36}Cl in calcite from limestone samples from Australia and Papua New Guinea. Erosion rates derived from these measurements range from 3 microns per year (Australia) to over 200 microns per year in the New Guinea highlands. 3 refs.

  11. Can playing the computer game "Tetris" reduce the build-up of flashbacks for trauma? A proposal from cognitive science.

    Science.gov (United States)

    Holmes, Emily A; James, Ella L; Coode-Bate, Thomas; Deeprose, Catherine

    2009-01-01

    Flashbacks are the hallmark symptom of Posttraumatic Stress Disorder (PTSD). Although we have successful treatments for full-blown PTSD, early interventions are lacking. We propose the utility of developing a 'cognitive vaccine' to prevent PTSD flashback development following exposure to trauma. Our theory is based on two key findings: 1) Cognitive science suggests that the brain has selective resources with limited capacity; 2) The neurobiology of memory suggests a 6-hr window to disrupt memory consolidation. The rationale for a 'cognitive vaccine' approach is as follows: Trauma flashbacks are sensory-perceptual, visuospatial mental images. Visuospatial cognitive tasks selectively compete for resources required to generate mental images. Thus, a visuospatial computer game (e.g. "Tetris") will interfere with flashbacks. Visuospatial tasks post-trauma, performed within the time window for memory consolidation, will reduce subsequent flashbacks. We predicted that playing "Tetris" half an hour after viewing trauma would reduce flashback frequency over 1-week. The Trauma Film paradigm was used as a well-established experimental analog for Post-traumatic Stress. All participants viewed a traumatic film consisting of scenes of real injury and death followed by a 30-min structured break. Participants were then randomly allocated to either a no-task or visuospatial ("Tetris") condition which they undertook for 10-min. Flashbacks were monitored for 1-week. Results indicated that compared to the no-task condition, the "Tetris" condition produced a significant reduction in flashback frequency over 1-week. Convergent results were found on a clinical measure of PTSD symptomatology at 1-week. Recognition memory between groups did not differ significantly. Playing "Tetris" after viewing traumatic material reduces unwanted, involuntary memory flashbacks to that traumatic film, leaving deliberate memory recall of the event intact. Pathological aspects of human memory in the aftermath of trauma may be malleable using non-invasive, cognitive interventions. This has implications for a novel avenue of preventative treatment development, much-needed as a crisis intervention for the aftermath of traumatic events.

  12. Transmission grid extensions during the build-up of a fully renewable pan-European electricity supply

    CERN Document Server

    Becker, Sarah; Andresen, Gorm B; Schramm, Stefan; Greiner, Martin

    2013-01-01

    Spatio-temporal generation patterns for wind and solar photovoltaic power in Europe are used to investigate the future rise in transmission needs with an increasing penetration of these variable renewable energy sources (VRES) on the pan-European electricity system. VRES growth predictions according to the official National Renewable Energy Action Plans of the EU countries are used and extrapolated logistically up to a fully VRES-supplied power system. We find that keeping today's international net transfer capacities (NTCs) fixed over the next forty years reduces the final need for backup energy by 13% when compared to the situation with no NTCs. An overall doubling of today's NTCs will lead to a 26% reduction, and an overall quadrupling to a 33% reduction. The remaining need for backup energy is due to correlations in the generation patterns, and cannot be further reduced by transmission. The main investments in transmission lines are due during the ramp-up of VRES from 15% (as planned for 2020) to 80%. Add...

  13. Quantification of Ash Deposit Build-up and Removal in a Straw and Wood Suspension-Fired Boiler

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

    2011-01-01

    deposit probe experiments revealed that deposit shedding was primarily through debonding from the surface of the tubes in the superheater region. Chemical analysis of fly ashes indicated that during suspension­firing of straw and wood, the fly ashes were rich in Si, K, Ca and Cl, but the relative......The aim of this study was to investigate ash deposit formation rate, heat uptake reduction and deposit removal by using advanced online ash deposition and sootblowing probes in a 350 MWth suspension­fired boiler, utilizing wood and straw pellets as fuel. The influence of fuel type (straw share...... in wood), probe exposure time, probe surface temperature (500, 550 and 600 oC) and flue gas temperature (600 ­1050 oC) on ash deposit formation rate, heat uptake by the probe, the fly ash and deposit characteristics, and deposit removal have been investigated. A systematic mathematical procedure was used...

  14. An advanced analytical solution for pressure build-up during CO2 injection into infinite saline aquifers: The role of compressibility

    Science.gov (United States)

    Wu, Haiqing; Bai, Bing; Li, Xiaochun

    2018-02-01

    Existing analytical or approximate solutions that are appropriate for describing the migration mechanics of CO2 and the evolution of fluid pressure in reservoirs do not consider the high compressibility of CO2, which reduces their calculation accuracy and application value. Therefore, this work first derives a new governing equation that represents the movement of complex fluids in reservoirs, based on the equation of continuity and the generalized Darcy's law. A more rigorous definition of the coefficient of compressibility of fluid is then presented, and a power function model (PFM) that characterizes the relationship between the physical properties of CO2 and the pressure is derived. Meanwhile, to avoid the difficulty of determining the saturation of fluids, a method that directly assumes the average relative permeability of each fluid phase in different fluid domains is proposed, based on the theory of gradual change. An advanced analytical solution is obtained that includes both the partial miscibility and the compressibility of CO2 and brine in evaluating the evolution of fluid pressure by integrating within different regions. Finally, two typical sample analyses are used to verify the reliability, improved nature and universality of this new analytical solution. Based on the physical characteristics and the results calculated for the examples, this work elaborates the concept and basis of partitioning for use in further work.

  15. Transport and build-up of tropospheric trace gases during the MINOS campaign: comparision of GOME, in situ aircraft measurements and MATCH-MPIC-data

    Directory of Open Access Journals (Sweden)

    A. Ladstätter-Weißenmayer

    2003-01-01

    Full Text Available The MINOS (Mediterranean INtensive Oxidant Study campaign was an international, multi-platform field campaign to measure long-range transport of air-pollution and aerosols from South East Asia and Europe towards the Mediterranean basin during August 2001. High pollution events were observed during this campaign. For the Mediterranean region enhanced tropospheric nitrogen dioxide (NO2 and formaldehyde (HCHO, which are precursors of tropospheric ozone (O3, were detected by the satellite based GOME (Global Ozone Monitoring Experiment instrument and compared with airborne in situ measurements as well as with the output from the global 3D photochemistry-transport model MATCH-MPIC (Model of Atmospheric Transport and CHemistry - Max Planck Institute for Chemistry. The increase of pollution in that region leads to severe air quality degradation with regional and global implications.

  16. Characterization and Quantification of Deposit Build-up and Removal in Straw Suspension-Fired Boilers - Ph.d. thesis Muhammad Shafique Bashir

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad

    An increased use of biomass in large suspension-red power plants can be a relatively economic and potentially also efficient way to utilize biomass for heat and power production. However, large deposit formation problems limit the electrical efficiency by limiting the maximum applicable superheat...

  17. Defense Infrastructure. Planning Challenges Could Increase Risks for DOD in Providing Utility Services When Needed to Support the Military Buildup on Guam

    Science.gov (United States)

    2009-06-01

    installations on Guam: the U.S. Naval Base-Guam, located on the southwestern side of the island at Apra Harbor, and Andersen Air Force Base in the...Force Base Apra Harbor Naval Complex Andersen South Naval Ordnance Annex Apra Heights Tenjo VIsta Tank Farm Sasa Valley Tank Farm Nimitz Hill Naval...gallons per day. In addition, DOD growth at Andersen Air Force Base and Apra Harbor is expected to result Potable water production

  18. Defense Infrastructure: DOD Needs to Provide Updated Labor Requirements to Help Guam Adequately Develop Its Labor Force for the Military Buildup

    Science.gov (United States)

    2009-10-01

    major installations on Guam: the U.S. Naval Base-Guam, located on the southwestern side of the island at Apra Harbor, and Andersen Air Force Base in...Andersen Air Force Base Apra Harbor Naval Complex Andersen South Naval Ordnance Annex Apra Heights Tenjo VIsta Tank Farm Sasa Valley Tank Farm Nimitz Hill

  19. Fast prediction of the fatigue behavior of short-fiber-reinforced thermoplastics based on heat build-up measurements: application to heterogeneous cases

    Science.gov (United States)

    Serrano, Leonell; Marco, Yann; Le Saux, Vincent; Robert, Gilles; Charrier, Pierre

    2017-09-01

    Short-fiber-reinforced thermoplastics components for structural applications are usually very complex parts as stiffeners, ribs and thickness variations are used to compensate the quite low material intrinsic stiffness. These complex geometries induce complex local mechanical fields but also complex microstructures due to the injection process. Accounting for these two aspects is crucial for the design in regard to fatigue of these parts, especially for automotive industry. The aim of this paper is to challenge an energetic approach, defined to evaluate quickly the fatigue lifetime, on three different heterogeneous cases: a classic dog-bone sample with a skin-core microstructure and two structural samples representative of the thickness variations observed for industrial components. First, a method to evaluate dissipated energy fields from thermal measurements is described and is applied to the three samples in order to relate the cyclic loading amplitude to the fields of cyclic dissipated energy. Then, a local analysis is detailed in order to link the energy dissipated at the failure location to the fatigue lifetime and to predict the fatigue curve from the thermomechanical response of one single sample. The predictions obtained for the three cases are compared successfully to the Wöhler curves obtained with classic fatigue tests. Finally, a discussion is proposed to compare results for the three samples in terms of dissipation fields and fatigue lifetime. This comparison illustrates that, if the approach is leading to a very relevant diagnosis on each case, the dissipated energy field is not giving a straightforward access to the lifetime cartography as the relation between fatigue failure and dissipated energy seems to be dependent on the local mechanical and microstructural state.

  20. A Study of Venezuela’s Internal and External Threat and the United States Security Assistance Program in the Build-Up and Modernization of Her Forces

    Science.gov (United States)

    1984-09-01

    Roques, Orchila, Blanquilla, Los Hermanos, Los Testigos, San Pedro , Cubagua, and Tobago (17:942). In addi- tion to the coast line, Venezuela has 1,059...kilometers and heights up to 4,000 meters; Paramo de Almorzadelo 4,000 meters; Paramo del Tama 3,613 meters; * 15 hyi- x Wo, V IOIUSIU ~ 4r.. 0Y \\ --Q( "Wo J

  1. Simulation studies on the electron cloud build-up in the elements of the LHC Arcs at 6.5 TeV

    CERN Document Server

    Dijkstal, Philipp; Mether, Lotta; Rumolo, Giovanni; CERN. Geneva. ATS Department

    2017-01-01

    The formation of electron clouds in the arcs of the Large Hadron Collider (LHC) has been identified as one of the main limitations for the performance of the machine. In particular, the impacting electrons can deposit a significant power on the cold beam screens of the LHC superconducting magnets, which translates into a significant heat load for the cryogenic system. A detailed model of the e-cloud formation in the different elements of the LHC arc half-cell has been developed using the PyECLOUD simulation code. The model includes the main dipole and quadrupole magnets, shorter corrector magnets and drift spaces. Particular care was taken to correctly model the impact of the hotoelectrons produced by the beam synchrotron radiation. For this purpose, we reviewed the available literature on the characterization of the LHC beam screen surface in terms of reflectivity and photoelectron yield and we defined the necessary steps to obtain the photoemission model in the format required in input by t...

  2. A dosimetric phantom study of dose accuracy and build-up effects using IMRT and RapidArc in stereotactic irradiation of lung tumours

    Directory of Open Access Journals (Sweden)

    Seppala Jan

    2012-05-01

    Full Text Available Abstract Background and purpose Stereotactic lung radiotherapy (SLRT has emerged as a curative treatment for medically inoperable patients with early-stage non-small cell lung cancer (NSCLC and the use of intensity-modulated radiotherapy (IMRT and volumetric modulated arc treatments (VMAT have been proposed as the best practical approaches for the delivery of SLRT. However, a large number of narrow field shapes are needed in the dose delivery of intensity-modulated techniques and the probability of underdosing the tumour periphery increases as the effective field size is decreased. The purpose of this study was to evaluate small lung tumour doses irradiated by intensity-modulated techniques to understand the risk for dose calculation errors in precision radiotherapy such as SLRT. Materials and methods The study was executed with two heterogeneous phantoms with targets of Ø1.5 and Ø4.0 cm. Dose distributions in the simulated tumours delivered by small sliding window apertures (SWAs, IMRT and RapidArc treatment plans were measured with radiochromic film. Calculation algorithms of pencil beam convolution (PBC and anisotropic analytic algorithm (AAA were used to calculate the corresponding dose distributions. Results Peripheral doses of the tumours were decreased as SWA decreased, which was not modelled by the calculation algorithms. The smallest SWA studied was 2 mm, which reduced the 90% isodose line width by 4.2 mm with the Ø4.0 cm tumour as compared to open field irradiation. PBC was not able to predict the dose accurately as the gamma evaluation failed to meet the criteria of ±3%/±1 mm on average in 61% of the defined volume with the smaller tumour. With AAA the corresponding value was 16%. The dosimetric inaccuracy of AAA was within ±3% with the optimized treatment plans of IMRT and RapidArc. The exception was the clinical RapidArc plan with dose overestimation of 4%. Conclusions Overall, the peripheral doses of the simulated lung tumours were decreased by decreasing the SWA. To achieve adequate surface dose coverage to small lung tumours with a difference less than 1 mm in the isodose line radius between the open and modulated field, a larger than 6 mm SWA should be used in the dose delivery of SLRT.

  3. Rapid Buildup of Genetic Diversity in Founder Populations of the Gynodioecious Plant Species Origanum vulgare after Semi-Natural Grassland Restoration

    Science.gov (United States)

    Helsen, Kenny; Jacquemyn, Hans; Hermy, Martin; Vandepitte, Katrien; Honnay, Olivier

    2013-01-01

    In most landscapes the success of habitat restoration is largely dependent on spontaneous colonization of plant species. This colonization process, and the outcome of restoration practices, can only be considered successful if the genetic makeup of founding populations is not eroded through founder effects and subsequent genetic drift. Here we used 10 microsatellite markers to investigate the genetic effects of recent colonization of the long-lived gynodioecious species Origanum vulgare in restored semi-natural grassland patches. We compared the genetic diversity and differentiation of fourteen recent populations with that of thirteen old, putative source populations, and we evaluated the effects of spatial configuration of the populations on colonization patterns. We did not observe decreased genetic diversity in recent populations, or inflated genetic differentiation among them. Nevertheless, a significantly higher inbreeding coefficient was observed in recent populations, although this was not associated with negative fitness effects. Overall population genetic differentiation was low (FST = 0.040). Individuals of restored populations were assigned to on average 6.1 different source populations (likely following the ‘migrant pool’ model). Gene flow was, however, affected by the spatial configuration of the grasslands, with gene flow into the recent populations mainly originating from nearby source populations. This study demonstrates how spontaneous colonization after habitat restoration can lead to viable populations in a relatively short time, overcoming pronounced founder effects, when several source populations are nearby. Restored populations can therefore rapidly act as stepping stones and sources of genetic diversity, likely increasing overall metapopulation viability of the study species. PMID:23840642

  4. Performance of a Novel Fertilizer-Drawn Forward Osmosis Aerobic Membrane Bioreactor (FDFO-MBR: Mitigating Salinity Build-Up by Integrating Microfiltration

    Directory of Open Access Journals (Sweden)

    Jin Wang

    2017-01-01

    Full Text Available In this paper, three different fertilizer draw solutions were tested in a novel forward osmosis-microfiltration aerobic membrane bioreactor (MF-FDFO-MBR hybrid system and their performance were evaluated in terms of water flux and reverse salt diffusion. Results were also compared with a standard solution. Results showed that ammonium sulfate is the most suitable fertilizer for this hybrid system since it has a relatively high water flux (6.85 LMH with a comparatively low reverse salt flux (3.02 gMH. The performance of the process was also studied by investigating different process parameters: draw solution concentration, FO draw solution flow rate and MF imposed flux. It was found that the optimal conditions for this hybrid system were: draw solution concentration of 1 M, FO draw solution flow rate of 200 mL/min and MF imposed flux of 10 LMH. The salt accumulation increased from 834 to 5400 μS/cm during the first four weeks but after integrating MF, the salinity dropped significantly from 5400 to 1100 μS/cm suggesting that MF is efficient in mitigating the salinity build up inside the reactor. This study demonstrated that the integration of the MF membrane could effectively control the salinity and enhance the stable FO flux in the OMBR.

  5. The 3 vs 1 game build-up effectiveness examination in physical and technical tests of 11-year-old football players

    Directory of Open Access Journals (Sweden)

    Tóth jr. Janos

    2014-01-01

    Full Text Available Study aim: The aim of this study is to prove that young players who have been coached with the main focus on technical ability and player interaction, perform better when tested on physical and technical attributes.

  6. Application of the quality index methodology for dosimetric verification of build-up effect beyond air-tissue interface in treatment planning system algorithms.

    Science.gov (United States)

    Caneva, Sandra; Tsiakalos, Miltiadis F; Stathakis, Sotirios; Zefkili, Sofia; Mazal, Alejandro; Rosenwald, Jean-Claude

    2006-05-01

    We have designed a simple benchmark test for the user of a treatment planning system to check the calculation algorithm's ability to model the build up effect beyond an air/tissue interface. The expected result is expressed as an inhomogeneity correction factor CF derived from measurements and from Monte Carlo calculations for a full range of photon beam qualities. The linear regression lines obtained from plotting CF as a function of beam quality index form the basis for a quantitative check of the algorithm performance.

  7. U-Th isotopes provide insights into the build-up to the 7.7 ka climactic eruption of Mount Mazama, Crater Lake, Oregon

    Science.gov (United States)

    Bosket, M. E.; Johnson, C.; Beard, B. L.; Bacon, C. R.

    2011-12-01

    Uranium-series isotope ratios determined on 35 whole-rock powders and 4 glass separates from preclimactic, climactic, and postcaldera volcanic rocks erupted from ~36 ka-4.8 ka at Mount Mazama, Crater Lake, Oregon identify both 230Th-excess and 238U-excess components. U-Th isotope ratios cover a very wide range of compositions, exceeding that yet measured for the entire Cascade arc. Age-corrected (230Th/232Th) and (238U/232Th) activity ratios range from 1.113-1.464 and 0.878-1.572 (44.4% 230Th-excess to 8.8% 238U-excess), respectively. These data identify a much stronger crustal influence than has previously been documented at Mount Mazama, and differentiate between lower crustal and upper crustal histories. The most distinctive aspect of our data is the contrast in 230Th-238U-232Th isotope ratios between low- and high-Sr (LSr, HSr) components identified by previous work, where the preclimactic/climactic LSr component exclusively contains 238U-excess (<1-8.8%) vs. the HSr component, as well as more primitive regional lavas, that are marked by 230Th-excess (2.6-44.4%). 230Th-excesses such as those we have recorded at Crater Lake are commonly observed in the Cascades. Melting-models suggest that the high 230Th-excess observed in the more primitive lavas probably involved an initial mantle melt of garnet lherzolite ((238U/232Th)=1.05), followed by mixing with a partial melt of a garnet-rich lower crustal composition (e.g. garnet amphibolite; (238U/232Th)=1.30). The presence of garnet is necessary in both the mantle and lower crust to explain the large 230Th-excesses. The extent of 238U-excess at Crater Lake has not yet been observed in Cascade volcanoes. At Crater Lake, 238U-excess occurs in more than half of the samples analyzed in this study. Traditionally, 238U-excess in arc magmas has been interpreted to record slab-fluid fluxing, but this is unlikely in the Cascade arc, because other isotopic and trace element data suggest a relatively minor role for slab-fluid fluxing. Instead, we hypothesize that 238U-excess reflects melting and assimilation of young, hydrothermally altered (U-enriched) upper crust with (238U/232Th)=1.30, beginning approximately 75 kyr ago. This may indicate the beginnings of a large shallow hydrothermal system. The preclimactic and climactic dacite and rhyodacite magmas, which also have 238U-excess, reflect mixing of the LSr and HSr components, consistent with prior studies. We suggest that the processes related to generating 238U-excess, especially in regard to proposed interaction with hydrothermally altered upper crust, are likely important factors in development of a large-scale silicic magma chamber and caldera-forming eruption relative to other Cascade volcanoes.

  8. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chidsey, Thomas C. Jr.; Eby, David E.; Wray, Laura L.

    2001-04-19

    The primary objective of this project was to enhance domestic petroleum production by demonstration and transfer of horizontal drilling technology in the Paradox basin, Utah, Colorado, Arizona, and New Mexico. If this project can demonstrate technical and economic feasibility, then the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 25 to 50 million barrels (40-80 million m3) of oil. This project was designed to characterize several shallow-shelf carbonate reservoirs in the Pennsylvania (Desmoinesian) Paradox Formation, choose the best candidate(s) for a pilot demonstration project to drill horizontally from existing vertical wells, monitor well performances, and report associated validation activities.

  9. Influence of process parameters on layer build-up and microstructure of Ti6Al4V (ELI) alloy on the optomec LENS

    CSIR Research Space (South Africa)

    Arthur, N

    2016-11-01

    Full Text Available . This approach also aids in limiting the development of residual stresses that can lead to crack formation [3]. Parts were fabricated in an argon atmosphere to reduce oxidation. Table 1: Process parameters Sample/Parameter Laser Power (W) Scan Speed (mm/s..., and were fabricated at scanning speeds of 10.58, 8.47 and 6.35 mm/s for a, b and c respectively as seen in Table 1. A thin film of oxidation can be seen on the surface of the builds due to oxygen content in the range of 60 to 90 ppm reported during...

  10. Structural and microstructural evolution of the Rattlesnake Mountain Anticline (Wyoming, USA): New insights into the Sevier and Laramide orogenic stress build-up in the Bighorn Basin

    Science.gov (United States)

    Beaudoin, Nicolas; Leprêtre, Rémi; Bellahsen, Nicolas; Lacombe, Olivier; Amrouch, Khalid; Callot, Jean-Paul; Emmanuel, Laurent; Daniel, Jean-Marc

    2012-11-01

    The Rocky Mountains in western US provide among the best examples of thick-skinned tectonics: following a period of thin-skinned tectonics related to the Sevier orogeny, the compressional reactivation of basement faults gave birth to the so-called Laramide uplifts/arches. The Bighorn basin, located in Wyoming, is therefore a key place to study the transition from thin- to thick-skinned tectonics in orogenic forelands, especially in terms of microstructural and stress/strain evolution. Our study focuses on a classic Laramide structure: the Rattlesnake Mountain Anticline (RMA, Wyoming, USA), a basement-cored anticline located in the western part of the Bighorn basin. Stress and strain evolution analysis in folded sedimentary layers and underlying faulted basement rocks were performed on the basis of combined analyses of fractures, fault-slip data and calcite twinning paleopiezometry. Most of the fractures are related to three main tectonic events: the Sevier thin-skinned contraction, the Laramide thick-skinned contraction, and the Basin and Range extension. Serial balanced cross-sections of RMA and displacement profiles suggest that all thrust faults were coeval, evidencing strain distribution in the basement during faulting. The comparison of RMA with another structure located in the eastern edge of the Bighorn basin, i.e. the Sheep Mountain Anticline (SMA), allows to propose a conceptual model for the geometric and kinematic evolution of Laramide-related basement-cored anticlines. Finally, the stress evolution is reconstructed at both the fold scale and the basin scale. We show that the evolution of stress trends and magnitudes was quite similar in both structures (RMA and SMA) during Laramide times (thick-skinned tectonics), in spite of different stress regimes. During Sevier (thin-skinned tectonics) and post-Laramide times, stress trends and fracture patterns were different in these two structures. These results suggest that the distance to the orogenic front influenced the fracture patterns but not the foreland stress magnitudes, which were likely controlled by the structural style.

  11. Multiscale Experimental and Numerical Approach to the Powder Particle Shape Effect on Al-Al2O3 Coating Build-Up

    Science.gov (United States)

    Leger, P. E.; Sennour, M.; Delloro, F.; Borit, F.; Debray, A.; Gaslain, F.; Jeandin, M.; Ducos, M.

    2017-10-01

    Aluminum (Al) powders with spherical and irregular particle shapes were mixed with two alumina (Al2O3) powders with either a spherical or an angular particle shape to achieve high-performance cold-sprayed coatings onto steel. Two effects of the aluminum particle shape were observed. First, coating microstructure observation showed impinging heterogeneity depending on particle shape. Second, particle jet differences depending on particle morphology were shown by velocity maps. From the latter, SEM and XRD, three effects of the alumina particle shape were also shown, i.e., higher in-flight velocity of angular particles, fragmentation of spherical hollow particles and embedding of alumina particles with aluminum. Numerical simulation of particle impacts was developed to study the densification of Al coating due to Al2O3 addition through elucidation of Al-Al2O3 interaction behavior at the scale of the coating. Al/Al and Al/Al2O3 interfaces were investigated using TEM to understand coating strengthening effects due to alumina addition at the scale of the particle. As a whole, Al and Al2O3 particle shape effects were claimed to explain coating mechanical properties, e.g., microhardness and coating-substrate bond strength. This study resulted in specifying criteria to help cold spray users in selecting powders for their applications, to meet economic and technical requirements.

  12. Royal jelly-like protein localization reveals differences in hypopharyngeal glands buildup and conserved expression pattern in brains of bumblebees and honeybees

    Directory of Open Access Journals (Sweden)

    Štefan Albert

    2014-03-01

    Full Text Available Royal jelly proteins (MRJPs of the honeybee bear several open questions. One of them is their expression in tissues other than the hypopharyngeal glands (HGs, the site of royal jelly production. The sole MRJP-like gene of the bumblebee, Bombus terrestris (BtRJPL, represents a pre-diversification stage of the MRJP gene evolution in bees. Here we investigate the expression of BtRJPL in the HGs and the brain of bumblebees. Comparison of the HGs of bumblebees and honeybees revealed striking differences in their morphology with respect to sex- and caste-specific appearance, number of cells per acinus, and filamentous actin (F-actin rings. At the cellular level, we found a temporary F-actin-covered meshwork in the secretory cells, which suggests a role for actin in the biogenesis of the end apparatus in HGs. Using immunohistochemical localization, we show that BtRJPL is expressed in the bumblebee brain, predominantly in the Kenyon cells of the mushroom bodies, the site of sensory integration in insects, and in the optic lobes. Our data suggest that a dual gland-brain function preceded the multiplication of MRJPs in the honeybee lineage. In the course of the honeybee evolution, HGs dramatically changed their morphology in order to serve a food-producing function.

  13. Build-up and functions of the transport control system at the Friedrich Heinrich/Rhineland mine; Aufbau und Funktionen des Transportleitsystems (TLS) auf dem Bergwerk Friedrich Heinrich/Rheinland

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, G. [Ruhrkohle Bergbau AG, Herne (Germany). Abt. ``Betriebsanalyse, Betriebsorganisation``

    1995-02-01

    In a project supported by the German Ministry of Research and Technology, a central transport control room above ground was developed at the Friedrich Heinrich/Rhineland mine. This control room will be based on a transport control system, a machine diagnosis system and a new type of speech and data radio. With this system, considerable potential rationalisation can be achieved for the material supply of underground hard coal mines. (orig.) [Deutsch] In einem vom Bundesministerium fuer Forschung und Technologie gefoerderten Vorhaben wurde auf dem Bergwerk Friedrich Heinrich/Rheinland der Ruhrkohle Bergbau AG eine zentrale Transportleitwarte ueber Tage entwickelt. Diese Warte wird sich im wesentlichen auf ein Transportleitsystem, ein Maschinendiagnosesystem und einen neuartigen Sprech- und Datenfunk stuetzen. Mit diesen Systemen lassen sich fuer die Materialversorgung untertaegiger Steinkohlenbergwerke erhebliche Rationalisierungspotentiale erschliessen. (orig.)

  14. Two improvements to the dynamic wake meandering model: including the effects of atmospheric shear on wake turbulence and incorporating turbulence build-up in a row of wind turbines

    DEFF Research Database (Denmark)

    Keck, Rolf-Erik; de Mare, Martin Tobias; Churchfield, Matthew J.

    2015-01-01

    agreement with the reference data. A quantitative comparison between the mean flow field of the DWM model with and without the suggested improvements, to that of the AL model, shows that the root-mean-square difference in terms of wind speed and turbulence intensity is reduced on the order of 30% and 40......%, respectively, by including the proposed corrections for a row of eight turbines. Furthermore, it is found that the root-mean-square difference between the AL model and the modified DWM model in terms of wind speed and turbulence intensity does not increase over a row of turbines compared with the root-mean-square...... shear on the wake deficit evolution by including a strain-rate contribution in the wake turbulence calculation. The method to account for the increased turbulence at a wake-affected turbine by basing the wake-added turbulence directly on the Reynolds stresses of the oncoming wake. This also allows...

  15. Thermal build-up, decay and retention responses to local therapeutic application of 448 kHz capacitive resistive monopolar radiofrequency: A prospective randomised crossover study in healthy adults.

    Science.gov (United States)

    Kumaran, Binoy; Watson, Tim

    2015-01-01

    Radiofrequency-based electrophysical agents are widely used in therapy-related clinical practice for their thermal effects, mainly relieving pain and inflammation and improving tissue extensibility. The most commonly used and researched are shortwave therapies that operate at 27.12 MHz. Although relatively new, electrophysical agents employing much lower frequencies have also emerged. Capacitive resistive monopolar radiofrequency employing 448 kHz is one such therapy. This laboratory-based study was aimed to investigate the skin thermal responses to 448 kHz radiofrequency-based therapy in healthy adults. In a two-group randomised crossover study, 15 volunteers attended two modes (capacitive and resistive) of 448 kHz radiofrequency-based therapy (using 'Indiba Activ 902') administered locally to the lower thigh region. Starting at minimum, the intensity was increased incrementally until thermal discomfort was felt. Participants reported three time points: thermal onset, definite thermal sensation, and onset of thermal discomfort. Local skin temperature was measured before, immediately post-treatment and up to 45 min post-treatment. Both capacitive and resistive modes of therapy significantly increased the skin temperature and sustained it over the 45-min follow-up. There was statistically significant difference between the thermal response patterns produced by the two modes. Peak post-treatment temperatures attained were not significantly different between the two; however, the retention rate at follow-up was significantly higher for the resistive mode. This study confirms that radiofrequency-based therapy at 448 kHz can significantly increase and sustain skin temperature. The study also provides useful baseline data for further research in the low frequency ranges of radiofrequency-based therapy that remain largely unexplored.

  16. Report on the KIMS-CNA Conference (2nd): The PLA Navy’s Build-Up and ROK-USN Cooperation, Held in Seoul, Korea on 20 November 2008

    Science.gov (United States)

    2009-02-01

    Zhuanjf ( Thailand Presents a Path for Overcoming China’s ’Malacca Dilemma’), Southern Daily, February 11,2004 Figure 3. China’s crude oil imports...34lead" of Brazil, India, and Malaysia and asserts the right to restrict military activities in their EEZ’s adjacent to their territorial claims to...straight baseline claim in an outbound transit from Hong Kong. In 1997, the USS Constellation (CV 64) transited inside of 12 NM of claimed straight

  17. Nitrate dosage system in a reclaimed wastewater pipeline for the inhibition of sulfide build-up; Sistema de dosificacion de nitrato en una conduccion de transporte de agua depurada para evitar la generacion de sulfuro

    Energy Technology Data Exchange (ETDEWEB)

    Monteagudo Perez-Machado, T.; Rodriguez Gomez, L. E.; Alvarez Diaz, M.

    2007-07-01

    During reclaimed wastewater transportation under anaerobic conditions sulfide generation may take place, which should be avoided due to the numerous problems related to it. This is the case of the reclaimed wastewater reuse scheme of Tenerife, one of whose elements is a completely filled 61 km long gravity pipeline, 0,60 m in diameter. In order to avoid the appearance of anaerobic conditions a controlled nitrate dosage system has been designed to be installed at the pipeline inlet, with nitrate dosage to be controlled by the organic matter content of the reclaimed wastewater, using turbidity as an indicator of it. (Author) 26 refs.

  18. Radiometric & Geometric normalization of Sentinel optical data and VHR data to build-up time-series, an example in Tonga for the monitoring of mangrove health vs. climate change

    Science.gov (United States)

    Serra, Romain; Valette, Anne; Taji, Amine; Emsley, Stephen

    2017-04-01

    Building climate resilience (i.e. climate change adaptation or self-renew of ecosystems) or planning environment rehabilitations and nature-based solutions to address their vulnerabilities to disturbances has prerequisites: 1- identify the disorder, i.e. stresses caused by events such as hurricanes, tsunamis, heavy rains, hailstone falls, smog… or piled-up along-time such as warming, rainfalls, ocean acidification, soil salinization… and measured by trends; and 2- qualify its impact on the ecosystems, i.e. the resulting strains. Mitigation of threats is accordingly twofold, i. on locally temporal scales for protection, ii. on long scale for prevention and sustainability. For assessment and evaluation prior to design future scenarios, it requires concomitant acquisition of (a) climate data at global and local spatial scale which describe the changes at the various temporal scales of phenomena without signal aliasing, and of (b) the ecosystems' status at the scales of the forcing and of relaxation times, hysteresis lags, periodicities of orbits in chaotic systems, shifts from one attractor in ecosystems to the others, etc. Dissociating groups of timescales and spatial scales facilitates the analysis and help set-up monitoring schemes. The Sentinel-2 mission, with a revisit of the earth every few days and a 10m resolution on-ground is a good automatic spectro-analytical monitoring system because detecting changes in numerous optical & IR bands at proper spatial scales for the description of land parcels. Combined with photo-interpreted VHR data which describe the environment more crudely but with high precision of land parcels' border locations, it helps find the relationship between stress and strains to empirically understand the relationships. An example is provided for Tonga, courtesy of ESA support and ADB request, with a focus on time-series' consistency that requires radiometric and geometric normalisation of EO data sets. Methodologies have been developed in the frame of ESA programs and EC program (H2020 Co-Resyf).

  19. U-Th and Os isotopes trace lower crustal interaction in magmas erupted during the build-up to the 7.7 ka climactic eruption of Mount Mazama, Crater Lake, Oregon

    Science.gov (United States)

    Ankney, M. E.; Johnson, C.; Bacon, C. R.; Hart, G. L.; Shirey, S. B.; Beard, B. L.

    2013-12-01

    High 230Th-excesses (up to 44.4%) are observed in mafic magmas erupted during the 30 kyr build up to the climactic caldera-forming eruption of Mount Mazama, Crater Lake, Oregon (Ankney et al., 2013, CMP). Modeling of U-Th isotope compositions and rare earth elements indicates that these can be attributed to interaction with mafic lower crust in the presence of garnet produced through the breakdown of amphibole and plagioclase during dehydration melting, given the strong affinity of garnet for U over Th. Importantly, dehydration melting in the lower crust may offer a solution to the 'hot arc' paradox of the Cascades, where low volatile contents are predicted due to high slab temperatures, yet higher water contents than expected have been documented in erupted lavas. Os isotopic composition is also particularly sensitive to interaction with mafic lower crust. Highly radiogenic (high 187Os/188Os) mafic crust relative to the mantle can develop in just a few million years due to the large Re-Os fractionation between the mantle and crust. By combining U-Th and Os isotope ratios it may be possible to confirm the presence of lower crustal interaction and also determine the amount of lower crust that has been incorporated into magmas rising from the mantle, an approach previously applied at Mt. Adams, another Cascade volcano, by Jicha et al. (2009, EPSL). Preliminary data for nine samples indicate that Os isotopic composition may be correlated with U-Th isotope composition at Mt. Mazama. The sample with the highest γOs (γOs=[(187Os/188Os)meas/(187Os/188Os)mantle-1]×100=118.9) also has the highest 230Th-excess (~14%) analyzed, whereas the sample with the lowest γOs (35.4) has the highest 238U-excess (~6%). Os isotope measurements for samples with higher 230Th-excesses (>20%) should have significantly higher γOs and, if so, will allow us to determine the amount of lower crustal assimilation these rocks experienced with more accuracy.

  20. Distinguishing lower and upper crustal processes in magmas erupted during the buildup to the 7.7 ka climactic eruption of Mount Mazama, Crater Lake, Oregon, using 238U-230Th disequilibria

    Science.gov (United States)

    Ankney, Meagan E.; Johnson, Clark M.; Bacon, Charles R.; Beard, Brian L.; Jicha, Brian R.

    2013-08-01

    Uranium-series isotope ratios determined for 35 volcanic rocks and 4 glass separates erupted from ~36 to 4.8 ka at Mt. Mazama, Crater Lake, Oregon, identify both 230Th-excess and 238U-excess components. U-Th isotope compositions cover a wide range, exceeding those previously measured for the Cascade arc. Age-corrected (230Th/232Th) and (238U/232Th) activity ratios range from 1.113 to 1.464 and from 0.878 to 1.572 (44.4 % 230Th-excess to 8.8 % 238U-excess), respectively. The most distinctive aspect of the data set is the contrast in U-Th isotope ratios between low and high Sr (LSr, HSr) components that have been previously identified in products of the 7.7 ka caldera-forming climactic eruption and preclimactic rhyodacite lavas. The LSr component exclusively contains 238U-excess, but the HSr component, as well as more primitive lavas, are marked by 230Th-excess. 230Th-excesses such as those recorded at Mt. Mazama are commonly observed in the Cascades. Melting models suggest that high 230Th-excesses observed in the more primitive lavas evolved through mixing of a mantle melt with a partial melt of a mafic lower crustal composition that contained garnet in the residuum that was produced through dehydration melting of amphibolite that was initially garnet free. Dehydration melting in the lower crust offers a solution to the "hot-slab paradox" of the Cascades, where low volatile contents are predicted due to high slab temperatures, yet higher water contents than expected have been documented in erupted lavas. The 238U-excess observed at Mt. Mazama is rare in Cascade lavas, but occurs in more than half of the samples analyzed in this study. Traditionally, 238U-excess in arc magmas is interpreted to reflect slab fluid fluxing. Indeed, 238U-excess in arcs is common and likely masks 230Th-excess resulting from lower crustal interaction. Isotopic and trace element data, however, suggest a relatively minor role for slab fluid fluxing in the Cascades. We propose that 238U-excess reflects melting and assimilation of young, hydrothermally altered upper crust. The processes related to generating 238U-excess are likely important features at Mt. Mazama that accompanied development of a large-scale silicic magma chamber that led to the caldera-forming eruption.

  1. Changing the paradigm for marine data production, dissemination and validation with Collaborative Platforms. The GlobColour webservice, a prime example which leads to the integration of CWE technologies to build-up virtual research centres.

    Science.gov (United States)

    Fanton d'Andon, Odile; Martin-Lauzer, François-Regis; Mangin, Antoine; Barrot, Gilbert; Clouaire, Stephane; Sardou, Olivier; Demaria, Julien; Serra, Romain

    2015-04-01

    The GlobColour webservice provides a rich dataset of marine bio-geochemical information for research and education purposes. We report on recent evolutions to improve the functionalities of the service to access EO and in-situ data and check information quality. In addition, a new concept, the Collaborative Platform, support the processing of bespoke information for remote users. At the root of the service is an integrated and automated production chain, processing not only EO satellite data but also in-situ measurements from bio-Argo floats. This production chain provides daily updated bio-geochemical data and performs automated data analysis (merging of sensors, temporal and spatial binning). The GlobColour webservice has been recently upgraded to provide improved navigation and selection capabilities. These evolutions were necessary as the catalogue of EO products has been significantly increased, with many new parameters, new spatial resolution (1 km over Europe in addition to 4 km global products) and projections (rectangular grid in addition to sinus grid). The validation and quality control of the information is essential to demonstrate the fitness-for-purpose of the service. Match-ups between in-situ measurements and EO data are a key element to establish the validity of the information. The standard approach is to perform these match-ups off-line using a database of in-situ measurements, and report the results in a validation document. Two innovations are introduced which greatly increase the value for the user: • An interactive navigation tool allows a detailed analysis the results of the match-ups, with temporal and geographical selection capabilities. Background information for each match-up can be easily retrieved, both for in-situ (measurement identification) and for satellite data (context retrieval, providing information such as cloud coverage and spatial variability). This allows users to get a better insight into the validity of the retrieved data for their particular applications. • Match-ups using real-time EO data and data collected from bio-Argo floats are processed automatically on-the-fly. • This is possible because quality control of the bio-Argo float data is also automated. A dedicated interface has been set-up to monitor the whole fleet of Bio-Argo floats, and access detailed information from each acquired profile. Finally, a Collaborative Platform has been developed to support R&D activities in parallel to the standard production chain, enabling users to work remotely within a dedicated production environment in order to develop new algorithms and methods. The Collaborative Platform is based on a Collaborative Working Environment, a secured IT environment mixing hardware and software elements. It provides access to raw data, to processing and storage facilities, to specific applicative software (e.g. visualisation and post-processing tools). In addition, collaborative tools to exchange data, information and ideas between participants (through forums, web-conferencing…) contribute to create a "Virtual Research Centre" preparing future evolutions of the service. Acknowledgements: This research received funding from the following projects: • MCGS project funded by the Fonds Unique Interministériel, French regional funds PACA and Bretagne, the Fonds Européen de Développement Régional • FP7 Copernicus projects OSS2015 (grant n° 282723) and E-AIMS (grant n° 312642). • The French EQUIPEX project NAOS

  2. Side Effects of HIV Medicines: HIV and Lipodystrophy

    Science.gov (United States)

    ... fat. A person with HIV can have fat loss or fat buildup or both. Whether the changes are noticeable or not depends on the degree of fat loss or fat buildup. The exact cause of lipodystrophy is unknown. ...

  3. Fiscal 1999 survey report. Survey of long-term strategy for energy technology: Volume 1 (Survey of foundation for strategy formulation for industrial technologies - strategy for environmental foundation buildup); 1999 nendo choki energy gijutsu senryaku nado ni kansuru chosa hokokusho. 1. Sangyo gijutsu senryaku sakutei kiban chosa (kankyo kiban seibi senryaku)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Japan has to prepare itself to behave accurately, and to stay technologically competitive, in the severe competition age to come in which it will fail to find leaders to follow. To fulfill this goal, Japan has to collect sufficient information and analyze it relative to the current state and future prospect of industrial technologies in Japan and overseas and various factors that will influence them, and to develop industrial technology related policies based firmly on scientific and theoretical foundations to be established using the thus-acquired knowledge. Under the circumstances, a survey is conducted of innovative, technological foundations, such as industrial technology related efforts in and out of Japan. The report consists of two volumes that cover what are described below. For the survey of technology related policies pursued in various countries abroad, literature and the like are investigated concerning technology related measures, budgets, and decision making processes in America, Britain, Germany, France, and the European Union, and the results are compiled so that their systems may be compared with each other. In the survey of Japan's technology related innovative systems, case studies are made about commodities over which Japan is relatively high in competitive power. Specifically, commodities manufactured by Japan's businesses and occupying 75% or more of the global share are investigated. (NEDO)

  4. 4-[18F]Fluorophenylpiperazines by Improved Hartwig-Buchwald N-Arylation of 4-[18F]fluoroiodobenzene, Formed via Hypervalent λ3-Iodane Precursors: Application to Build-Up of the Dopamine D4 Ligand [18F]FAUC 316

    Directory of Open Access Journals (Sweden)

    Fabian Kügler

    2014-12-01

    Full Text Available Substituted phenylpiperazines are often neuropharmacologically active compounds and in many cases are essential pharmacophores of neuroligands for different receptors such as D2-like dopaminergic, serotoninergic and other receptors. Nucleophilic, no-carrier-added (n.c.a. 18F-labelling of these ligands in an aromatic position is desirable for studying receptors with in vivo molecular imaging. 1-(4-[18F]Fluorophenylpiperazine was synthesized in two reaction steps starting by 18F-labelling of a iodobenzene-iodonium precursor, followed by Pd-catalyzed N-arylation of the intermediate 4-[18F]fluoro-iodobenzene. Different palladium catalysts and solvents were tested with particular attention to the polar solvents dimethylformamide (DMF and dimethylsulfoxide (DMSO. Weak inorganic bases like potassium phosphate or cesium carbonate seem to be essential for the arylation step and lead to conversation rates above 70% in DMF which is comparable to those in typically used toluene. In DMSO even quantitative conversation was observed. Overall radiochemical yields of up to 40% and 60% in DMF and DMSO, respectively, were reached depending on the labelling yield of the first step. The fluorophenylpiperazine obtained was coupled in a third reaction step with 2-formyl-1H-indole-5-carbonitrile to yield the highly selective dopamine D4 ligand [18F]FAUC 316.

  5. Pressure Build-up and Decay in Acid Gas Injection Operations in Reefs in the Zama Field, Canada, and Implications for CO2 Storage Variations de pression au cours de l’injection de gaz acides dans le réservoir récifal duchamp de Zama, Canada. Implications pour le stockage géologique de CO2

    Directory of Open Access Journals (Sweden)

    Pooladi-Darvish M.

    2011-03-01

    Full Text Available The objective of this paper is to examinereasons for pressure rise in the Zama X2X pool in northwestern Alberta, Canada, that was used foracid gas disposal, and whether subsequent pressure decay was a result of pressure dissipation into a larger aquifer. The Zama X2X pool, approximately 1 km2 in size, is connected to four other nearby poolsthrough a common underlying aquifer. Pressure analysis for all the pools indicates that they are in goodhydraulic communication. Initial pressure in the Zama X2X pool was approximately 15 MPa. Pressuredeclined first during oil production, stabilizing at around 10 MPa in the early 1970s, after which started toincrease such that it reached 26 MPa in 1986. Subsequently, pressure declined reaching 22 MPa by 1995just prior to starting injection of acid gas (80% CO2 and 20% H2S. The operator injected acid gas at lowerrates and wellhead pressures than those licensed by the regulatory agency. Despite significant production ofwater and hydrocarbons, the pressure in the Zama X2X pool continued to be higher than the initial reservoirpressure by more than 5 MPa, such that disposal operations were suspended in late 1998. Oil productioncontinued all this time until 2002. Numerical simulations using CMG-IMEXTM and corresponding sensitivity studies reported in this papershow that disposal of more than 1 million m3 of water between 1970 and 1988 and again in 1992-1993 inthe adjacent Zama YY pool, which is in good hydrodynamic communication with the Zama X2X poolthrough the aquifer below the oil column, is the main reason for the high pressures observed in the ZamaX2X pool. Sensitivity studies indicate that pressure decay in the X2X pool was due to fluid production.The study indicates that while pressure rise has been caused by hydraulic communication between theX2X and YY pools through the common aquifer, the aquifer was not of large volume to allow dissipationof the pressure. In addition to the case study, the implications of pressure communication to geological storage of CO2 in aquifers are briefly discussed. Le but de l’article est de comprendre l’accroissement de pression dans le gisement de Zama X2X, utilisé pour le stockage degaz acide (NO de l’Alberta, Canada, et aussi d’examiner si la baisse de pression, observée ultérieurement,est la conséquence d’une dissipation par un aquifère de grande taille. Le gisement de Zama X2X, d’uneextension de 1 km2 environ, est connecté à quatre autres gisements voisins par l’intermédiaire d’un aquifère commun sous-jacent. L’analyse de la pression à travers tous ces gisements indique un bon niveau decommunication hydraulique. La pression initiale de l’accumulation de Zama X2X était d’environ 15 MPa.Pendant la production d’huile, la pression a commencé par décroître, pour se stabiliser vers 10 MPa audébut de la décennie 1970. Mais ensuite la pression a repris son ascension, jusqu’à atteindre 26 MPa en1986. Un nouvel épisode de baisse est alors intervenu et la pression s’est établie vers 22 MPa en 1995,au moment où l’on a commencé à injecter du gaz acide (80 % CO2 et 20 % H2S – l’opérateur, toutefois,injectait ce gaz à des débits et à des pressions en tête de puits qui se situaient en deçà des seuils autoriséspar l’Administration. En dépit d’une production significative d’eau et d’hydrocarbures, la pression à ZamaX2X est ensuite restée plus élevée que la pression vierge, d’au moins 5 MPa, au point qu’en 1998 les opérations d’injection de gaz furent suspendues. La production d’huile a cependant été maintenue jusqu’en 2002. Des simulations numériques effectuées avec CMG-IMEXTM, assorties d’une analyse de sensibilité,montrent ici que la ré-injection de plus de 1 million de m3 d’eau dans le gisement voisin de Zama YY,entre 1970 et 1988 puis en 1992-93, est la principale cause du comportement de la pression à Zama X2X.Les deux champs sont en effet connectés hydrauliquement via l’aquifère situé au-dessous de la colonned’huile. L’analyse de sensibilité indique que la baisse de pression un moment enregistrée à Zama X2Xétait due à la production de fluides, mais aussi que l’aquifère commun n’est pas d’une dimension suffisante pour permettre une dissipation rapide et complète des effets de pression. Ce cas d’étude illustretoute l’importance, pour la transmission des pressions lors du stockage géologique de CO2, de la connectivité entre les réservoirs concernés.

  6. Contribution to the build-up of a core calculation frame: comparison between ``diffusion`` and ``SP{sub n}`` operators on various configurations of the first N4 core; Contribution a l`elaboration d`un schema de coeur en transport: comparaison des operateurs ``diffusion`` et ``SP{sub n}`` sur differentes configurations du premier coeur N4

    Energy Technology Data Exchange (ETDEWEB)

    Magat, Ph

    1997-04-01

    The aim of this study is to compare two calculation methods implemented in the neutronic code CRONOS 2: the diffusion approximation and the SP{sub n} method. The APOLLO 2 code is used to build the multiparameter cross section libraries.The comparison is based on the first core of N4 type Chooz reactor. The rod worth and the power map have been calculated. Some recommendations about the SP{sub n} development order of flux are made and the results show that the diffusion calculations over-estimate the black rod efficiency up to 10%. (A.C.) 12 refs.

  7. Swollen Knee (Water on the Knee)

    Science.gov (United States)

    ... buildup in and around the knee joint include: Osteoarthritis Rheumatoid arthritis Infection Gout Pseudogout Bursitis Cysts Tumors Risk factors Age. Your likelihood of developing a swollen knee ...

  8. Genetics Home Reference: familial partial lipodystrophy

    Science.gov (United States)

    ... of fats called triglycerides circulating in the bloodstream (hypertriglyceridemia), which can lead to inflammation of the pancreas (pancreatitis). Familial partial lipodystrophy can also cause an abnormal buildup ...

  9. Suspension-Firing of Biomass

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

    2012-01-01

    This paper is the second of two papers, describing probe measurements of deposit buildup and removal (shedding), conducted in a 350 MWth suspension-fired boiler, firing straw and wood. Investigations of deposit buildup and shedding have been made by use of an advanced online deposit probe and a s...

  10. Organic Matter Dynamics in Soils Regenerating from Degraded ...

    African Journals Online (AJOL)

    The area of secondary forest (SF) regenerating from degraded abandoned rubber (Hevea brasiliensis) plantation is increasing in the rainforest zone of south southern Nigeria; however, the build-up of soil organic matter following abandonment is not well understood. This study examined the build-up of soil organic matter in ...

  11. Take-Off. De opbouw van de Nederlandse luchtstrijdkrachten 1945-1973

    NARCIS (Netherlands)

    van der Vegt, Q.J.

    2013-01-01

    There has been little academic focus on the build-up of the Dutch Air Force after the Second World War. The aim of this study is to identify the key developments in the build-up and sustainment of the Dutch air force between 1945 and 1973 and to answer the question as to which factors and actors

  12. Mechanical characterization and modeling of curing thermosets

    NARCIS (Netherlands)

    Van 't Hof, C.

    2006-01-01

    Chemical shrinkage and simultaneous build-up of mechanical properties in curing thermosets leads to the build-up of residual stresses and strains. Depending on the constraints these may cause interface failure, dimensional inaccuracy or failure in the thermoset or its surrounding structure. The

  13. Calculation of Dose Gamma Ray Build up Factor in Some ...

    African Journals Online (AJOL)

    The gamma ray buildup factor was calculated by analyzing the narrow- beam and broad-beam geometry equations using Taylor's formula for isotropic sources and homogeneous materials. The buildup factor was programmed using MATLAB software to operate with any radiation energy (E), atomic number (Z) and the ...

  14. Improvement of the gamma-ray transport model the point kernel attenuation method; Amelioration de la modelisation du transport des gamma suivant la methode de l`attenuation en ligne droite

    Energy Technology Data Exchange (ETDEWEB)

    Assad, A.

    1995-12-01

    The gamma-ray buildup factor is a multiplicative factor which corrects the response of non-collided photons to include the contribution of the scattered photons. Buildup factors are very important data implemented in Point kernel codes for use in shield design. We propose in this study, a new evaluation of gamma-ray buildup factors which takes into account all the interaction modes of photons with matter, in the energy range of 15 KeV to 10 MeV, for materials of atomic number Z=1 to Z=92. The analytical representation, called Geometric Progression, has been applied to reproduce the buildup factors calculated within a few percent. This formula can be used to interpolate the buildup factors over the full range of distance, energy and atomic number. We tackle also the calculation of buildup factors in stratified shields and propose a new approximate formula to calculate the buildup factors in these complex configurations. (authors). 77 refs., 55 figs., 33 tabs.

  15. Direct Numerical Modeling of E-Cloud Driven Instability of a Bunch Train in the CERN SPS

    CERN Document Server

    Vay, J-L; Furman, M A

    2011-01-01

    The simulation package WARP-POSINST was recently upgraded for handling multiple bunches and modeling concurrently the electron cloud buildup and its effect on the beam, allowing for direct self-consistent simulation of bunch trains generating, and interacting with, electron clouds. We have used the WARP-POSINST package on massively parallel supercomputers to study the buildup and interaction of electron clouds with a proton bunch train in the CERN SPS accelerator. Results suggest that a positive feedback mechanism exists between the electron buildup and the e-cloud driven transverse instability, leading to a net increase in predicted electron density.

  16. Investigation of some radiation shielding parameters in soft tissue

    Directory of Open Access Journals (Sweden)

    Danial Salehi

    2015-07-01

    Full Text Available The photon interactions with the soft tissue have been discussed mainly in terms of mass attenuation coefficient, mass energy absorption coefficient, kerma relative to air, effective atomic number and energy absorption buildup factor in the energy range 0.01–10 MeV and penetration depth up to 40 mfp (by using GP fitting method. Over past 2 decades, interest has been growing for theoretical and computational works on photon buildup factor in soft tissue. Actually, besides dosimetry, in radiation therapy and imaging the buildup of X- and gamma photons introduces remarkable error.

  17. Recent findings on sinks for sulfide in gravity sewer networks

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2006-01-01

    , sulfide emission and thereby potential hydrogen sulfide buildup in the sewer atmosphere is of particular importance in sewers constructed with large diameter pipes, in sewers constructed with steep slopes and in sewers conveying low pH wastewater. Precipitation of metal sulfides is only important when......Sulfide buildup in sewer networks is associated with several problems, including health impacts, corrosion of sewer structures and odor nuisance. In recent years, significant advances in the knowledge of the major processes governing sulfide buildup in sewer networks have been made. This paper...

  18. Bronchiolitis

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000975.htm Bronchiolitis To use the sharing features on this page, please enable JavaScript. Bronchiolitis is swelling and mucus buildup in the smallest ...

  19. Integration of the Army National Guard into the Total Army

    National Research Council Canada - National Science Library

    Stohla, Stephen

    1998-01-01

    .... Recently, however, the "rift" has escalated. Much of this "rift" has come on the heels of the Reagan Administration military buildup and from the Quadrennial Defense Review (QDR) panel findings...

  20. Kidney Problems

    Science.gov (United States)

    ... High Blood Pressure Nutrition Join our e-newsletter! Aging & Health A to Z Kidney Problems Basic Facts & ... build-up of waste products, and other serious consequences in later years. Doses of medications must also ...

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... in the portal vein system. This pressure buildup can cause blood to flow backward from the liver ... to cirrhosis (scarring of the liver). Portal hypertension can also occur in children, although children are much ...

  2. Medline Plus

    Full Text Available ... Damage to or blockage of a coronary artery can result in injury to the heart. Normally, blood ... coronary artery unimpeded. However, a process called atherosclerosis can cause a buildup of cholesterol and cells and ...

  3. Dissolved methane in Indian freshwater reservoirs

    Digital Repository Service at National Institute of Oceanography (India)

    Narvenkar, G.; Naqvi, S.W.A.; Kurian, S.; Shenoy, D.M.; Pratihary, A.K.; Naik, H.; Patil, S.; Sarkar, A.; Gauns, M.

    reservoirs in India, most of which experience seasonal anaerobic conditions and CH4 buildup in the hypolimnia. However, strong stratification prevents the CH4-rich subsurface layers to ventilate CH4 directly to the atmosphere, and surface water CH4...

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the heart). A stent is then placed in this tunnel to keep the pathway open. Patients who ... have increased pressure in the portal vein system. This pressure buildup can cause blood to flow backward ...

  5. Composition of microfouling on aluminium and fibre glass panels exposed in Agatti waters (Lakshadweep Island)

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Sankaran, P.D.; Wagh, A.B.

    Rate of microfouling build-up was high during the initial periods of exposure of test surfaces but decreased with the increasing duration. Fibre glass surfaces showed higher deposition than those of aluminium. Carbohydrates and lipids were the major...

  6. High potassium level

    Science.gov (United States)

    ... the blood. This buildup can be due to: Addison disease . Disease in which the adrenal glands do not ... used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed ...

  7. Sodium blood test

    Science.gov (United States)

    ... Adrenal glands not making enough of their hormones ( Addison disease ) Buildup in urine of waste product from fat ... used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed ...

  8. Coronary artery disease (image)

    Science.gov (United States)

    ... through these arteries is critical for the heart. Coronary artery disease usually results from the build-up of fatty material and plaque, a condition called atherosclerosis. As the coronary arteries narrow, the flow of blood to the ...

  9. 40 CFR 94.215 - Maintenance of records; submittal of information; right of entry.

    Science.gov (United States)

    2010-07-01

    ... production engine, a general description of the buildup of the engine (e.g., whether experimental heads were... applicable), intake air pressurization and cooling system components, cylinders, pistons and piston rings...

  10. Leg Problems

    Science.gov (United States)

    ... Self CareSee your doctor as soon as possible.Start OverDiagnosisYou may have EDEMA, a build-up of fluids that may be caused from HEART FAILURE, KIDNEY DISEASE or blockage of blood returning to ...

  11. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... they have increased pressure in the portal vein system. This pressure buildup can cause blood to flow ... the hepatic vein to identify the portal venous system. Access is then gained from the hepatic vein ...

  12. Genetics Home Reference: Dandy-Walker malformation

    Science.gov (United States)

    ... Walker malformation , signs and symptoms caused by abnormal brain development are present at birth or develop within the first year of life. Some children have a buildup of fluid in the brain ( ...

  13. Genetics Home Reference: cystic fibrosis

    Science.gov (United States)

    ... Email Facebook Twitter Home Health Conditions Cystic fibrosis Cystic fibrosis Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Cystic fibrosis is an inherited disease characterized by the buildup ...

  14. Medline Plus

    Full Text Available ... cholesterol, and other substances. Eventually, the material builds up and a plaque is formed, narrowing the artery. When the build-up is severe, a clot could block the vessel ...

  15. Anaerobic

    Science.gov (United States)

    ... them during shorter, more intense activities like sprinting. Anaerobic exercise leads to a buildup of lactic acid in ... Asplund CA, Best TM. Exercise physiology. In: Miller MD, Thompson ... Douglas, and Bennett's Principles and Practice of Infectious ...

  16. Fragment-based design for the development of N-domain-selective angiotensin-1-converting enzyme inhibitors

    National Research Council Canada - National Science Library

    Douglas, Ross G; Sharma, Rajni K; Masuyer, Geoffrey; Lubbe, Lizelle; Zamora, Ismael; Acharya, K Ravi; Chibale, Kelly; Sturrock, Edward D

    2014-01-01

    .... The design of inhibitors that selectively inhibit the N-domain (N-selective) could be useful in treating conditions of tissue injury and fibrosis due to build-up of N-domain-specific substrate Ac-SDKP...

  17. Lumacaftor and Ivacaftor

    Science.gov (United States)

    ... body to decrease the build-up of thick mucus in the lungs and improving other symptoms of ... Rifater, Rimactane), and telithromycin (Ketek); certain medications for diabetes such as chlorpropamide (Diabinese), glimepiride (Amaryl, in Duetact), ...

  18. What drives the increased phytoplankton biomass in the Arabian Sea?

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Roshin, R.P.; Narvekar, J.; DineshKumar, P.K.; Vivekanandan, E.

    phytoplankton biomass during September-October to dust-induced iron fertilization when there is sufficient buildup of nitrate in the upper ocean. During winter, the enhanced evaporative cooling under the strengthening winds led to the increased convective mixing...

  19. Medline Plus

    Full Text Available ... flows through a coronary artery unimpeded. However, a process called atherosclerosis can cause a buildup of cholesterol ... of the artery forming a plaque. If this process restricts blood flow enough it may result in ...

  20. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... you’re taking. You may be advised to stop taking aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs) or ... the portal vein system. This pressure buildup can cause blood to flow backward from the liver into ...

  1. Medline Plus

    Full Text Available ... artery unimpeded. However, a process called atherosclerosis can cause a buildup of cholesterol and cells and other ... lack of oxygen to the heart muscle and cause angina. If the inner wall of a coronary ...

  2. Medline Plus

    Full Text Available ... fat, cholesterol, and other substances. Eventually, the material builds up and a plaque is formed, narrowing the artery. When the build-up is severe, a clot could block the ...

  3. Computer Calculation of Fire Danger

    Science.gov (United States)

    William A. Main

    1969-01-01

    This paper describes a computer program that calculates National Fire Danger Rating Indexes. fuel moisture, buildup index, and drying factor are also available. The program is written in FORTRAN and is usable on even the smallest compiler.

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... system. This pressure buildup can cause blood to flow backward from the liver into the veins of ... does the procedure work? A TIPS reroutes blood flow in the liver and reduces abnormally high blood ...

  5. Tay-Sachs Disease

    Science.gov (United States)

    ... SEARCH Definition Treatment Prognosis Clinical Trials Organizations Publications Definition Tay-Sachs disease is a inherited metabolic disease caused by the harmful buildup of lipids (fatty materials such as oils and acids) in ...

  6. Les monticules micritiques sinemuriens sur la transversale de Midelt-Errachidia (Haut Atlas Central, Maroc)

    National Research Council Canada - National Science Library

    Taj Eddine, K; Souhel, A; Canérot, J; Chafiki, D

    2004-01-01

    In the central High Atlas of Morocco, the Liassic series present different mud-moundtype carbonate buildups, well developed in the Midelt area, towards the boundary between the Lower and the Upper Sinemurian...

  7. Development of arctic wind technology

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, H.; Marjaniemi, M.; Antikainen, P. [VTT Energy, Espoo (Finland)

    1998-10-01

    The climatic conditions of Lapland set special technical requirements for wind power production. The most difficult problem regarding wind power production in arctic regions is the build-up of hard and rime ice on structures of the machine

  8. Advanced Material Studies for Additive Manufacturing in terms of Future Gear Application

    Directory of Open Access Journals (Sweden)

    Jan Bräunig

    2014-06-01

    Full Text Available Additive manufacturing by laser beam melting is predestined for complex component geometry like integrated cooling channels without enormous posttreatment processing. To investigate the influence of build-up direction in terms of later tooth excitation of gear-wheels, first fundamental material analyses were accomplished in this publication. Therefore, additively produced specimens were used to determine the build-up direction dependent elastic properties of the material in all three spatial directions based on tensile and torsion tests. The anisotropies of elastic limits and breaking points of previous studies were confirmed in this paper. Furthermore, torsion values were also determined depending on build-up direction. Laser beam melted X3NiCoMoTi18-9-5 (hot-work tool steel was shown to exhibit extremely high performance under shear loading in comparison to conventionally processed steel. The influence of build-up direction on torsional strength was also shown.

  9. Can North Korean Airborne Special Purpose Forces Successfully Conduct Military Operations Against the United States and South Korea?

    National Research Council Canada - National Science Library

    Allmond, Samuel

    2003-01-01

    ...; and secondly by producing the world's largest SPF. North Korea (NK) has built the world's largest SPF in the world with more than 100,000 men to support surprise attacks to disrupt CFC combat buildup and operations...

  10. Payments for Debts Associated With Exercise Can Become Higher as We Age and Limit Exercise CapacityEditorials published in the Journal of American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology

    National Research Council Canada - National Science Library

    Edward G Lakatta; Paul D Chantler

    2006-01-01

      Notwithstanding that, the greater lactate build-up by working muscles and the general increase in core temperature during exercise in older versus young persons need to be dissipated during recovery from exercise...

  11. Genetics Home Reference: hepatic veno-occlusive disease with immunodeficiency

    Science.gov (United States)

    ... liver (hepatomegaly), a buildup of scar tissue (hepatic fibrosis), and liver failure. Children with VODI are prone to recurrent ... be inherited? More about Inheriting Genetic Conditions Diagnosis & Management Resources Genetic Testing (1 link) Genetic Testing Registry: ...

  12. Genetics Home Reference: Mainzer-Saldino syndrome

    Science.gov (United States)

    ... in a buildup of scar tissue in the liver (hepatic fibrosis); cerebellar ataxia, which is difficulty with coordination and ... be inherited? More about Inheriting Genetic Conditions Diagnosis & Management Resources Genetic Testing (1 link) Genetic Testing Registry: ...

  13. Estimating Carbon Dioxide Concentration Near an Infant's Face, Case 95-43604

    National Research Council Canada - National Science Library

    Eaton, David

    1997-01-01

    Dr. Stephen Wetmore, Coroner, Ministry of the Solicitor General, asked DCIEM to investigate the possibility that carbon dioxide build-up may have been a predisposing factor in the death of an infant...

  14. Linking Air Pollution and Heart Disease

    Science.gov (United States)

    Science Matters article about a study finding that exposure to particulate matter and nitrogen oxides can prematurely age blood vessels and contribute to a more rapid buildup of calcium in the coronary artery.

  15. Is fracture resistance of endodontically treated mandibular molars restored with indirect onlay composite restorations influenced by fibre post insertion?

    National Research Council Canada - National Science Library

    Scotti, Nicola; Coero Borga, Francesco Andrea; Alovisi, Mario; Rota, Riccardo; Pasqualini, Damiano; Berutti, Elio

    2012-01-01

    .... Endodontically treated human molars with two- and one-wall cavities either underwent or did not undergo fibre post insertion within composite build-up before cementation of indirect composite onlay restorations...

  16. TETRAPOLIS - an exercise in building the complexities of proximity space

    National Research Council Canada - National Science Library

    Cristian Blidariu; Diana Giurea

    2017-01-01

    ... student’s intuitive ways for understanding these vicinities, their physical and symbolic proximities, through participatory tactics and certain poetic/architectural tools required in the phenomenological build-up of space...

  17. Trace Contaminant Monitor for Air in Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A need exists for analyzers that can measure trace contaminants in air on board spacecraft. Toxic gas buildup can endanger the crew particularly during long...

  18. Nevus

    Science.gov (United States)

    ... freckle of the eye.” It is a common, colored growth, similar to a mole on your skin. ... Cause Calcium Build-Up? Sep 25, 2015 Orthokeratology Lenses and Contact Fitting Sep 10, 2015 Duration of Dilating Drops ...

  19. Comparative Evaluation of Compressive Strength and Flexural Strength of Conventional Core Materials with Nanohybrid Composite Resin Core Material an in Vitro Study

    OpenAIRE

    Jayanthi, Narasimha; Vinod, V.

    2013-01-01

    Several dental materials have been used for core build-up procedures. Most of these materials were not specifically developed for this purpose, but as a consequence of their properties, have found application in core build-up procedures. Improvements in composites and the development of nanocomposites have led to their use as a core build up material due to their superior mechanical properties, optical properties and ease of handling. However it is not clear if they have better mechanical pro...

  20. Proceedings of the Electronics Manufacturing Seminar (14th Annual) Held in China Lake, California on 21-22 February 1990

    Science.gov (United States)

    1990-02-01

    polyimide flexible connections (Figure 8) * Figure 8 133 NWC TP 7066 EMPF TR 0010 and aluminium Backplane assemblies incorporated within this packaging...configurations but also tend to speed dross buildup. APPLICATIONS CONSIDERATIONS The usefulness of a technology is in its application. Many good, immediate...bridging, eliminates icicles on the ends of leads and minimizes dross buildup on the surface of the solder. Many fine pitch components have been

  1. The Future Strategic Environment of East Asia: Implications of a PRC-Taiwan Reunification

    Science.gov (United States)

    2011-09-01

    partisanship, objectivity, and empiricism that is the hallmark of CNA research. Our program is built upon a foundation of analytic products and hosted...global and regional security environment—not on China’s past practice. A reunified China would view itself as having scored a major ideological ...viewed as contributing to a “strategic encirclement and blockading of China by the U.S. military”29  Military buildups (particularly naval buildups) by

  2. Oil-productive Miocene algal and sea grass carbonate mudbanks, south Sumatra, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Longman, M.W.; Beddoes, L.R. Jr.

    1985-02-01

    Ramba and Tanjung Laban oil fields, located about 70 km northwest of Palembang in southern Sumatra, produce from wackestones and packstones in the lower Miocene Batu Raja Formation. Reservoir rocks are part of relatively small, undolomitized, low-relief carbonate buildups that accumulated on a widespread platform facies. Rocks in the platform facies are dominantly shaly nodular wackestones, whereas rocks in the buildup are dominantly nonshaly wackestones and packstones. The regional setting, the abundance of micrite in the buildups, the absence of both coralline algae and marine cements, and the geometry of the buildups suggest that noncalcareous algae and/or sea grasses were the dominant organisms responsible for forming these mudbanks. The absence of shale in the mudbanks has been important in forming the secondary porosity that yields most of the oil. Vugs and molds form as much as 30% of the rock in the best reservoir zones. Fractures formed by dissolution and collapse greatly enhance reservoir zones quality in many places. Another type of porosity, microintercrystalline, occurs within chalky micrites scattered through the upper part of the buildups. Porosity in these micrites reaches 25%, but permeability is very low. The recent discovery of oil in these low-energy carbonate mudbanks of the Batu Raja Formation has opened a new exploration play in the South Sumatra basin. Many similar buildups will likely be found as exploration continues and the basin's paleogeography becomes better understood.

  3. [Parameter identification and validation of SWMM in simulation of impervious urban land surface runoff].

    Science.gov (United States)

    Dong, Xin; Du, Peng-fei; Li, Zhi-yi; Wang, Hao-chang

    2008-06-01

    The purpose of this paper is the application of storm water management model (SWMM) in simulating runoff hydrology and water quality. The study chose a roof as the typical impervious urban land surface, and monitored several rainfall-runoff events for parameter identification. We identified and validated hydrological and water quality parameters, using Monte Carlo sampling method and HSY algorithm, which are based on uncertainty analysis. Results show that impervious urban land surface runoff model includes 6 critical parameters, which are depression storage (S-imperv), Manning's n (N-imperv), maximum buildup possible (max buildup), buildup rate constant (rate constant), washoff coefficient (coefficient), and washoff exponent (exponent). Identification of S-imperv and N-imperv could use least square error as objectives, while others could use errors of event pollution load and peak concentration of pollutant as objectives. The identification results of the 6 parameters are N-imperv 0.012-0.025,S-imperv 0-0.7, max buildup 15-30,rate constant 0.2-0.8,coefficient 0.01-0.05, and exponent 1.0-1.2. Regional sensitivities of these parameters in non-ascending order are coefficient, S-imperv, N-imperv, max buildup, exponent, and rate constant. Identified parameters are able to be validated by SWMM model. However, current model structures still have some difficulties in simulating runoff pollutant concentration curves caused by some special rain patterns.

  4. Ultrasonic Apparatus and Method to Assess Compartment Syndrome

    Science.gov (United States)

    Yost, William T. (Inventor); Ueno, Toshiaki (Inventor); Hargens, Alan R. (Inventor)

    2009-01-01

    A process and apparatus for measuring pressure buildup in a body compartment that encases muscular tissue. The method includes assessing the body compartment configuration and identifying the effect of pulsatible components on compartment dimensions and muscle tissue characteristics. This process is used in preventing tissue necrosis, and in decisions of whether to perform surgery on the body compartment for prevention of Compartment Syndrome. An apparatus is used for measuring pressure build-up in the body compartment having components for imparting ultrasonic waves such as a transducer, placing the transducer to impart the ultrasonic waves, capturing the imparted ultrasonic waves, mathematically manipulating the captured ultrasonic waves and categorizing pressure build-up in the body compartment from the mathematical manipulations.

  5. EXPLORATION WELL TEST CASE HISTORY CONFIRMS IMPORTANCE OF DST

    Directory of Open Access Journals (Sweden)

    Dario Damjanić

    2009-12-01

    Full Text Available Drill stem testing of the exploration well consisted of two flow and two pressure build-up periods. Gas was obtained. Modified isochronal test was used during testing the well after completion. Except gas, small quantity of condensate and traces of oil and water were obtained. Both pressure build-up analyses showed that formation permeability is low. DST pressure build-up analysis showed that wellbore damage is present. This was proved later, when acid treatment was performed, by which skin was removed and production increased significantly. Data obtained by well testing are very important for future productivity prediction and determination of optimal well completion and surface facility construction (the paper is published in Croatian.

  6. The Military Dimension of American Hegemony

    Directory of Open Access Journals (Sweden)

    IONELA BĂLŢĂTESCU

    2015-05-01

    Full Text Available A Political Economy of American Hegemony - Buildups, Booms and Busts by Thomas Oatley offers relevant historical and statistical evidence regarding military buildups in postwar America, assessing the economic and political impact of deficit financed military spending. From this point of view the book proves to be a very instructive and challenging reading. Thomas Oatley is professor of political science at North Carolina University, teaching courses on international politics and political economy. He is also the author of a series of papers and books on international political economy. His main theme of research is the interaction between economic interests and political institutions and how it shaped governments’ foreign economic policies. A Political Economy of American Hegemony Buildups, Booms and Busts is the most recent and also the most challenging of his books, in terms of inquired questions and defended theses.

  7. Upflow bioreactor with septum and pressure release mechanism

    Science.gov (United States)

    Hansen, Conly L.; Hansen, Carl S.; Pack, Kevin; Milligan, John; Benefiel, Bradley C.; Tolman, C. Wayne; Tolman, Kenneth W.

    2010-04-20

    An upflow bioreactor includes a vessel having an inlet and an outlet configured for upflow operation. A septum is positioned within the vessel and defines a lower chamber and an upper chamber. The septum includes an aperture that provides fluid communication between the upper chamber and lower chamber. The bioreactor also includes means for releasing pressure buildup in the lower chamber. In one configuration, the septum includes a releasable portion having an open position and a closed position. The releasable portion is configured to move to the open position in response to pressure buildup in the lower chamber. In the open position fluid communication between the lower chamber and the upper chamber is increased. Alternatively the lower chamber can include a pressure release line that is selectively actuated by pressure buildup. The pressure release mechanism can prevent the bioreactor from plugging and/or prevent catastrophic damage to the bioreactor caused by high pressures.

  8. Mitigating fouling in the high temperature paraffinic froth treatment process through science and serendipity

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, Tapantosh [Imperial Oil Resources (Canada)], email: apan.chakrabarty@esso.ca

    2010-07-01

    This work focuses on the application of high temperature paraffinic froth treatment (HT-PFT); a technique used to clean froth that results from the process of water extraction of oil sands. This technique includes the addition of a paraffinic solvent to the bitumen as a preliminary step in removing froth structures, leading to a possible fouling of the inner walls of the treatment vessels. Therefore, a fouling preventive technique consisting of three novel solutions was investigated in this work. The accumulations of fouling components were constantly monitored during the HT-PFT process using a gamma-ray densitometer. Results showed that buildups mostly consisted of inorganic solid structures held together with asphaltene. It was also shown that fluorocarbon polymer coating (FPC) proved to be the most effective additive in preventing fouling buildups, and by using fouling collectors in the vessels buildups were highly reduced downstream. In general, incorporating this preventive technique with HT-PFT was recommended.

  9. A Morphological Approach to the Modeling of the Cold Spray Process

    Science.gov (United States)

    Delloro, F.; Jeandin, M.; Jeulin, D.; Proudhon, H.; Faessel, M.; Bianchi, L.; Meillot, E.; Helfen, L.

    2017-12-01

    A coating buildup model was developed, the aim of which was simulating the microstructure of a tantalum coating cold sprayed onto a copper substrate. To do so, first was operated a fine characterization of the irregular tantalum powder in 3D, using x-ray microtomography and developing specific image analysis algorithms. Particles were grouped by shape in seven classes. Afterward, 3D finite element simulations of the impact of the previously observed particles were realized. To finish, a coating buildup model was developed, based on the results of finite element simulations of particle impact. In its first version, this model is limited to 2D.

  10. Residual Stress Induced by Nitriding and Nitrocarburizing

    DEFF Research Database (Denmark)

    Somers, Marcel A.J.

    2005-01-01

    The present chapter is devoted to the various mechanisms involved in the buildup and relief of residual stress in nitrided and nitrocarburized cases. The work presented is an overview of model studies on iron and iron-based alloys. Subdivision is made between the compound (or white) layer, develo......, developing at the surfce and consisting of iron-based (carbo)nitrides, and the diffusion zone underneath, consisting of iron and alloying element nitrides dispersed in af ferritic matrix. Microstructural features are related directly to the origins of stress buildup and stres relief....

  11. Experimental validation of a mathematical model for seabed liquefaction in waves

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Kirca, Özgür; Fredsøe, Jørgen

    2011-01-01

    This paper summarizes the results of an experimental study directed towards the validation of a mathematical model for the buildup of pore water pressure and resulting liquefaction of marine soils under progressive waves. Experiments were conducted under controlled conditions with silt ( d50 = 0.......070 mm) in a wave flume with a soil pit. Waves with wave heights in the range 7.7-18 cm with the water depth 55 cm and the wave period 1.6 s enabled us to study both the liquefaction and no-liquefaction regime pore water pressure buildup. The experimental data was used to validate the model. A numerical...

  12. X-ray depth-dose characteristics of the Toshiba LMR-16.

    Science.gov (United States)

    Mantel, J; Perry, H; Weinkam, J J

    1979-01-01

    The depth-dose characteristics of the Toshiba LMR-16 linear accelerator for 14-MeV x rays have been measured at an SSD of 100 cm using diodes and ion chambers. The surface dose and build-up depth both exhibit a considerable variation with field size. A new central axis model has been developed which takes account of these variations, and the agreement between the measured and computed data using this model is found to be excellent. Formulas are also presented to estimate the surface dose, buildup depth, and output factor as a function of field size.

  13. Experimental Determination and Numerical Modelling of Process Induced Strains and Residual Stresses in Thick Glass/Epoxy Laminate

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Hattel, Jesper Henri; Løgstrup Andersen, Tom

    2012-01-01

    In this work, a cure hardening instantaneous linear elastic (CHILE) model and a path dependent (PD) constitutive approach are compared, for the case of modelling strain build-up during curing of a thick composite laminate part. The PD approach is a limiting case of viscoelasticity with path...... dependency on temperature and cure degree. Model predictions are compared to experimentally determined in-situ strains, determined using FBG sensors. It was found that both models offer good approximations of internal strain build-up. A general shortcoming is the lack of capturing rate-dependent effects...

  14. Effects of noncontact cleaners on transparent solar materials

    Energy Technology Data Exchange (ETDEWEB)

    Hampton, H.L.; Lind, M.A.

    1979-04-01

    A brief study has been undertaken to evaluate the performance of noncontact cleaning agents for use on solar collectors. Several techniques are used to compare cleansing agents which have been recommended by their respective manufacturers for cleaning solar mirrors. Wetting and residue buildup properties are evaluated for over 50 of these commercially available cleaners. The wetting properties of each cleaner are evaluated by measuring the growth of the contact area of a constant volume drop as a function of time. Losses due to residue buildup are solar weighted and considered equally with the wetting parameters and cost figures to construct a figure of merit for cleaner comparison.

  15. Shift designs for freight handling personnel at air cargo terminals

    DEFF Research Database (Denmark)

    Rong, Aiying; Grunow, Martin

    2009-01-01

    This paper presents an integrated mixed integer linear programming (MILP) model for determining manpower requirements and related personnel shift designs for the build-up and break-down of the unit load devices (ULDs) at the air cargo terminal to minimize manpower costs. To utilize the manpower...... resources efficiently, we implement a new mechanism for demand leveling. In addition, we consider the qualification hierarchy between build-up and break-down workers. A case study based on the real-life data shows that the model is useful for manpower planning at air cargo terminals and the integrated...

  16. A Study of the Effects of Altitude on Thermal Ice Protection System Performance

    Science.gov (United States)

    Addy, Gene; Oleskiw, Myron; Broeren, Andy P.; Orchard, David

    2013-01-01

    Thermal ice protection systems use heat energy to prevent a dangerous buildup of ice on an aircraft. As aircraft become more efficient, less heat energy is available to operate a thermal ice protections system. This requires that thermal ice protection systems be designed to more exacting standards so as to more efficiently prevent a dangerous ice buildup without adversely affecting aircraft safety. While the effects of altitude have always beeing taked into account in the design of thermal ice protection systems, a better understanding of these effects is needed so as to enable more exact design, testing, and evaluation of these systems.

  17. An assessment of residual ovine nematodes on pasture under maritime conditions.

    Science.gov (United States)

    Smith, H J; Fulton, N R

    1989-01-01

    Residual ovine nematode pasture infections were assessed by grazing groups of ewes and their lambs on permanent sheep and cattle pastures and by the use of tracer lambs. Ostertagia spp., Cooperia oncophora, Nematodirus spp., Chabertia ovina and Trichuris spp. eggs and/or larvae survived on pastures overwinter. Second generation Ostertagia larvae were present in greatest numbers on pasture during the latter part of August and early September. The failure of a significant build-up of Cooperia oncophora was attributed to negligible worm egg output of this species in sheep. A build-up of Nematodirus spp. on pasture was not detected in this study. PMID:2766155

  18. How do clinicians and suicide attempters understand suicide attempt impulsivity? A qualitative study.

    Science.gov (United States)

    Rimkeviciene, Jurgita; O'Gorman, John; De Leo, Diego

    2016-01-01

    Inconsistencies in the definition of impulsive suicide attempts hamper research integration. To expand the currently limited data on how this construct is used in clinical practice, researchers interviewed eight suicide attempters to create timelines of their suicide process, then had seven experienced clinicians review these timelines. Thematic analysis of the patient and clinician data revealed three themes: "thinking out," build-up, and unclear intentionality. The results imply that assessing build-up of agitation and exhaustion symptoms can contribute to understanding acuteness of suicide risk. In addition, uncertainty about one's intentions during the attempt should not be equated to low intent to die.

  19. Tapered US carbon emissions during good times: what's old, what's new?

    Science.gov (United States)

    Eng, Yoke-Kee; Wong, Chin-Yoong

    2017-11-01

    In light of a slow buildup in CO2 emissions since the recovery, this paper revisits the relationship between CO2 emissions and the US economy using a nonlinear autoregressive distributed lag model, in which the determinants are identified through an expanded real business cycle model. We find convincing evidence that CO2 emissions decline more rapidly during recessions than increase during expansions over the long run. Of all determinants considered, long-run asymmetry is fostered once vehicle miles traveled is controlled. This calls for a greater attention to public transportation development and vehicle miles traveled tax for slowing down stock buildup of CO2 emissions during good times.

  20. A Morphological Approach to the Modeling of the Cold Spray Process

    Science.gov (United States)

    Delloro, F.; Jeandin, M.; Jeulin, D.; Proudhon, H.; Faessel, M.; Bianchi, L.; Meillot, E.; Helfen, L.

    2017-09-01

    A coating buildup model was developed, the aim of which was simulating the microstructure of a tantalum coating cold sprayed onto a copper substrate. To do so, first was operated a fine characterization of the irregular tantalum powder in 3D, using x-ray microtomography and developing specific image analysis algorithms. Particles were grouped by shape in seven classes. Afterward, 3D finite element simulations of the impact of the previously observed particles were realized. To finish, a coating buildup model was developed, based on the results of finite element simulations of particle impact. In its first version, this model is limited to 2D.

  1. Towards an All-Polymer Biosensor for Early Alzheimer's Disease

    DEFF Research Database (Denmark)

    Christiansen, Nikolaj Ormstrup; Heegaard, Niels

    Alzheimer's disease (AD) is quickly evolving into one of the biggest and most costly health issues in Europe and the United States. AD is a protein misfolding disease, caused by accumulation of abnormally folded β-amyloid and tau protein in the brain. The build-up of protein is believed to degene......Alzheimer's disease (AD) is quickly evolving into one of the biggest and most costly health issues in Europe and the United States. AD is a protein misfolding disease, caused by accumulation of abnormally folded β-amyloid and tau protein in the brain. The build-up of protein is believed...

  2. familiarity with modern health management trends by west african

    African Journals Online (AJOL)

    2010-09-09

    Sep 9, 2010 ... ones related to marketing strategies. Respondent largely found the listed ..... Rating of the ease with which customers could effect some transactions without being physically present with their health institutions by West ... crucial to marketing strategies that facilitate build-up and retention of loyal patients.

  3. Dietary Tools To Modulate Glycogen Storage In Fish Muscle: A Proteomic Assessment

    DEFF Research Database (Denmark)

    Silva, Tomé S.; Matos, Elisabete; Cordeire, Odete

    Post-mortem flesh deterioration is dependent on the energy reserves present at the time of death. Early depletion of muscle glycogen leads to the buildup of lactate and to the early onset of rigor mortis, resulting in the activation of endogenous proteases and the degradation of myofibrillar prot...

  4. Review on hardfacing as method of improving the service life of ...

    African Journals Online (AJOL)

    Most welding methods were identified to be successfully used in applying consumable on substrate surfaces. Dilution decreases with increase in the number of hardfacing layers. Buffers, butters and build-up metals are used to compensate for composition differences to prevent spalling, overcome welding difficulties and ...

  5. Intumescent coatings under fast heating

    DEFF Research Database (Denmark)

    Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Català, Pere

    2012-01-01

    Intumescent coatings are widely used to delay or minimise the destructive effects of fire. They are usually tested under conditions that simulate the relatively slow build-up of heat in a normal fire. Here, the effects of damage during a fire causing sudden heating of the coating were studied....

  6. Trapping effects and acoustoelectric current saturation in ZnO single crystals

    DEFF Research Database (Denmark)

    Mosekilde, Erik

    1970-01-01

    Measurements of current-voltage characteristics for ZnO single crystals at temperatures between 77 and 640 °K are reported. Because of the buildup of an intense acoustic flux, a strong current saturation sets in when the trap-controlled electron drift velocity is equal to the velocity of sound...

  7. Optical control of antibacterial activity

    NARCIS (Netherlands)

    Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

    2013-01-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly

  8. Experimental Determination and Numerical Modelling of Process Induced Strains and Residual Stresses in Thick Glass/Epoxy Laminate

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Hattel, Jesper Henri; Løgstrup Andersen, Tom

    2012-01-01

    In this work, a cure hardening instantaneous linear elastic (CHILE) model and a path dependent (PD) constitutive approach are compared, for the case of modelling strain build-up during curing of a thick composite laminate part. The PD approach is a limiting case of viscoelasticity with path...

  9. Tailoring Wettability Through the Surface Modification of Electro-spun Polymers by Plasma and Sol-gel Treatments

    Science.gov (United States)

    2014-11-01

    nanoparticles , sol-gel reactions and by producing beads-on-a-string morphologies. Low surface energy was added by using fluorinated polymers, or through... nanoparticles ................................................................... 13 3.2.3 Effect of TEOS addition to electrospinning solutions...could benefit a number of applications: anti-biofouling; corrosion resistant paints for hulls; coatings that prevent ice buildup; water, stain and

  10. Modeling relationships among 217 fires using remote sensing of burn severity in southern pine forests

    Science.gov (United States)

    Sparkle L. Malone; Leda N. Kobziar; Christina L. Staudhammer; Amr Abd-Elrahman

    2011-01-01

    Pine flatwoods forests in the southeastern US have experienced severe wildfires over the past few decades, often attributed to fuel load build-up. These forest communities are fire dependent and require regular burning for ecosystem maintenance and health. Although prescribed fire has been used to reduce wildfire risk and maintain ecosystem integrity, managers are...

  11. Deposit Probe Measurements in Large Biomass-Fired Grate Boilers and Pulverized-Fuel Boilers

    DEFF Research Database (Denmark)

    Hansen, Stine Broholm; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    2014-01-01

    A number of full-scale deposit probe measuring campaigns conducted in grate-fired and suspension-fired boilers, fired with biomass, have been reviewed and compared. The influence of operational parameters on the chemistry of ash and deposits, on deposit build-up rates, and on shedding behavior has...

  12. Dissociation between behavior and motor cortical excitability before and during ballistic wrist flexion and extension in young and old adults

    NARCIS (Netherlands)

    Hortobágyi, Tibor; Mieras, Adinda; Rothwell, John; Fernandez del Olmo, Miguel

    2017-01-01

    Purpose: Aging is associated with slow reactive movement generation and poor termination. Objective: We examined the hypothesis that the build-up of excitability in the primary motor cortex in the agonist muscle to generate ballistic wrist flexion and extension and in the antagonist to stop the

  13. Development of new imaging techniques for the study and interpretation of late Rembrandt paintings

    NARCIS (Netherlands)

    Noble, P.; van Loon, A.; van der Snickt, G.; Janssens, K.; Alfeld, M.; Dik, J.; Bridgland, J.

    2014-01-01

    Recent macro-XRF scanning of Rembrandt’s Selfportrait from 1669 in the Mauritshuis – as part of the ReVisRembrandt project – has revealed significant new information about the pigments and build-up of the painting. The elemental distribution maps make clear that the umber-rich ground plays a very

  14. Coupled Finite Element/Boundary Element Analysis of a Vehicle Moving Along a Railway Track

    DEFF Research Database (Denmark)

    Andersen, Lars; Nielsen, Søren R. K.

    2004-01-01

    Trains running in build-up areas are a source to ground-borne noise. A careful design of the track structure may be one way of minimizing the vibrations in the surroundings. For example, open or in-filled trenches may be constructed along the track, or the soil underneath the track may be improve...

  15. Rewaterproofing Silica Tiles

    Science.gov (United States)

    Lleger, L. J.; Wade, D. C.

    1983-01-01

    Waterproofing agent, vaporized in bubbler transported by gas flowing in system and deposits in pores of tiles. Vapor carried through hole of approximately 1/16 inch (1.6.mm) diameter made in tile coating. Technique used to waterproof buildups (concrete and brick) and possibly fabrics.

  16. ST-LO (7 July -19 July 1944)

    Science.gov (United States)

    1946-08-21

    attacks was not let­ ting lip , and German efforts to cOllnterattack had exhausted their small potelltial reserves. The 2d SS Panzer units, as a result of... bumper to bumper , is going through in build-up of th e breakthrough, already pushed as far as Brittany. 127 replacements; Selle 11th Army ellen

  17. External human factors in incident management team decisionmaking and their effect on large fire suppression expenditures

    Science.gov (United States)

    Janie Canton-Tompson; Krista M. Gebert; Brooke Thompson; Greg Jones; David Calkin; Geoff. Donovan

    2008-01-01

    Large wildland fires are complex, costly events influenced by a vast array of physical, climatic, and social factors. Changing climate, fuel buildup due to past suppression, and increasing populations in the wildland-urban interface have all been blamed for the extreme fire seasons and rising suppression expenditures of recent years. With each high-cost year comes a...

  18. Evaluation of the AC and DC Characteristics of Rock Conductivity.

    Science.gov (United States)

    1978-09-27

    conduction through the major minera l phases, or with charge build-up along grain boundaries and cracks. Another possibility is contact polari- zation...leaching and hydration of susceptible minera l sur faces . In addition to open cracks, the Wausau granite also contains a network of reddish colored

  19. 77 FR 76871 - Approval and Promulgation of Implementation Plans; State of Colorado; Regional Haze State...

    Science.gov (United States)

    2012-12-31

    ... typically excluded when following the CCM methodology, including royalties, initial catalyst and chemicals... pollutant reductions, and that distillate oil, ethanol, and biodiesel are high cost fuels for boilers of... potential for dust buildup on the catalyst, ``which ] be influenced by site specific raw material...

  20. Human Nature in the Adaptation of Trust

    NARCIS (Netherlands)

    Nooteboom, B.

    2006-01-01

    This chapter pleads for more inspiration from human nature, in agent-based modeling.As an illustration of an effort in that direction, it summarizes and discusses an agentbased model of the build-up and adaptation of trust between multiple producers and suppliers.The central question is whether, and

  1. Consistent seasonal snow cover depth and duration variability over ...

    Indian Academy of Sciences (India)

    of fresh water for many perennial river systems. (Dettinger and Cayan 1995; ... management, planning and decision making for various socio-economic ... Methodology. Seasonal snow cover build-up for a winter season is broadly described by snow cover depth and its duration. Variability in winter weather patterns. Table 1.

  2. The Impact of Market Reform Programmes on Coffee Prices in ...

    African Journals Online (AJOL)

    This paper presents an empirical investigation of the effect of collapse of International Coffee Agreement (ICA) and liberalization of coffee marketing in Tanzania on coffee prices. The motivation for this analysis is that the ICA regulatory system reduced price volatility by encouraging the build-up of stocks during surplus years ...

  3. Carbon cycling in the northern Arabian Sea during the northeast monsoon: Significance of salps

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.; Sarma, V.V.S.S.; Jayakumar, D.A.

    for filter feeders that can efficiently utilize abundant smaller plankton. This may lead to periodic removal of chlorophyll, thereby moderating primary production as well as episodic build-up of DOC in the upper layers. This DOC pool may be used as a nutrient...

  4. Recent trends in salinity control for soilless growing systems management

    NARCIS (Netherlands)

    Katsoulas, N.; Voogt, W.

    2014-01-01

    The consequences of closed hydroponic systems, the impact of salinity build-up on crop yield and product quality are reviewed. Soilless cultivation, especially in closed-loop systems offers a great option for water saving in greenhouses. Capture and recycling of the drainage will considerably

  5. JPRS Report, Near East & South Asia

    Science.gov (United States)

    1990-06-22

    the first place; this is the opinion of Dr. Avner Falk, a clinical psychologist and psychohistorian who is studying the uses of psychoanalysis for...to go on. This calls for no bravado on our part and no build-up of the war- psychosis as India is currently engaged in. Let us realise, in the light

  6. Contamination control: removing small particles from increasingly large wafers

    NARCIS (Netherlands)

    Jong, A.J. de; Donck, J.C.J. van der; Huijser, T.; Kievit, O.; Koops, R.; Koster, N.B.; Molkenboer, F.T.; Theulings, A.M.M.G.

    2012-01-01

    With the introduction of 450 mm wafers, which are considerably larger than the currently largest wafers of 300mm, handling with side grippers is no longer possible and backside grippers are required. Backside gripping increases the possible buildup of particles on the backside of the wafers with

  7. Biomorphic microstructures of ferromanganese stromatolites

    Science.gov (United States)

    Avdonin, V. V.; Yeryomin, N. I.; Zhegallo, E. A.; Sergeyeva, N. E.

    2016-11-01

    It was found as a result of detailed study of ferromanganese stromatolites that columnar formations, i.e., fossilized stratified bacterial tufts with rhythmically alternating layers of glycocalyx, accumulations of filamentous bacteria, and lens-shaped two-layered (alternation of homogeneous microlayers with porous ones containing filamentous bacteria trichomes) packages, serve as the basis for stromatolite buildup.

  8. Ultrastructures of stromatolites from the Wenlockian of Chernov Swell

    Science.gov (United States)

    Matveev, V. A.

    2017-05-01

    The morphology of fossilized biogenic particles and the elemental composition of biogenic formations, discovered for the first time in Lower Silurian deposits within the Timan-Northern Urals region, are considered. The diversity of biogenic formations identified in stromatolites indicates a high level of activity of microorganisms forming the cyanobacterial mat and confirms the microbial origin of the Wenlockian stromatolite buildups.

  9. A new conceptual model for the fate of lignin in decomposing plant litter

    NARCIS (Netherlands)

    Klotzbücher, T.; Kaiser, K.; Guggenberger, G.; Gatzek, C.; Kalbitz, K.

    2011-01-01

    Lignin is a main component of plant litter. Its degradation is thought to be critical for litter decomposition rates and the build-up of soil organic matter. We studied the relationships between lignin degradation and the production of dissolved organic carbon (DOC) and of CO2 during litter

  10. Experimental Validation of a Mathematical Model for Seabed Liquefaction Under Waves

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Kirca, Özgür; Fredsøe, Jørgen

    2012-01-01

    This paper summarizes the results of an experimental study directed towards the validation of a mathematical model for the buildup of pore water pressure and resulting liquefaction of marine soils under progressive waves. Experiments were conducted under controlled conditions with silt (d(50) = 0...

  11. Dynamics of soil organic matter in primary and secondary forest succession on sandy soils in The Netherlands: An application of the ROMUL model

    NARCIS (Netherlands)

    Nadporozhskaya, M.A.; Mohren, G.M.J.; Chertov, O.G.; Komarov, A.S.; Mikhailov, A.V.

    2006-01-01

    We applied the simulation model ROMUL of soil organic matter dynamics in order to analyse and predict forest soil organic matter (SOM) changes following stand growth and also to identify gaps of data and modelling problems. SOM build-up was analysed (a) from bare sand to forest soil during a primary

  12. Upwelling intensity modulates N2O concentrations over the western Indian shelf

    Digital Repository Service at National Institute of Oceanography (India)

    Sudheesh, V.; Gupta, G.V.M.; Sudharma, K.V.; Naik, H.; Shenoy, D.M.; Sudhakar, M.; Naqvi, S.W.A.

    observation also. This perhaps is a vital first-step (apart from prima- ry productivity) in controlling the observed shift in sediment nature from nonsulfidic to sulfidic. This transi- tion period was found to have highest buildup of N2O (765 nM) in the CEAS...

  13. Guided wave sensing of polyelectrolyte multilayers

    DEFF Research Database (Denmark)

    Horvath, R.; Pedersen, H.C.; Cuisinier, F.J.G.

    2006-01-01

    A planar optical waveguide configuration is proposed to monitor the buildup of thick polyelectrolyte multilayers on the surface of the waveguide in aqueous solutions. Instead of detecting the layer by the electromagnetic evanescent field the polyelectrolyte layer acts as an additional waveguiding...... film that is sensed by guided waves instead of evanescent waves. This leads to a considerably improved sensitivity and dynamic range....

  14. Gas transport in the excavation damage zone of a final storage in clay rock; Untersuchungen zum Gastransport in der Auflockerungszone in einem geologischen Endlager in Tongestein

    Energy Technology Data Exchange (ETDEWEB)

    Haefner, Benjamin

    2014-05-13

    As a reference scenario for this thesis a gas pressure build-up in the post closure phase of a final storage for highly active nuclear waste storage is postulated. The mass transport mechanisms in the excavation damage zone relevant for this case are identified under varying scenario relevant boundary conditions. The contribution of these mechanisms to overall mass transport is quantified.

  15. Measuring the Components of Ecosystem Respiration in the Headwaters of the White River

    Science.gov (United States)

    Brown, Courtney

    2006-01-01

    Sediment oxygen demand (SOD) is the rate that dissolved oxygen leaves the water column in a body of water due to the build-up and decomposition of organic carbons in the sediment. The introduction of organic materials changes the chemistry of streams, and many chemical reactions occurring in bodies of water, with the exception of photosynthesis,…

  16. Selection of assessment methods for evaluating banana weevil ...

    African Journals Online (AJOL)

    Mo

    Oviposition is in the base of the banana mat. The larvae tunnel in the corm and lower pseudostem. Most attack occurs below the soil surface. Pupation is within the plant. Population build-up is slow and weevil problems become increasingly important in ratoon crops. Damage is caused entirely by larval feeding. Weevil ...

  17. On the possible causes of the seasonal phytoplankton blooms along the southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Banse, K.; Sumitra-Vijayaraghavan; Madhupratap, M.

    then can materially increase in numbers, since they are poorly controlled by grazers. It so, the principal role of the high nutrient oncentrations would be to permit the build-up of a large algal biomass and pigment concentrations that, coupled...

  18. Response of soricid populations to repeated fire and fuel reduction treatments in the southern Appalachain Mountains

    Science.gov (United States)

    Charlotte E Matthews; Christopher E Moorman; Cathryn H Greenberg

    2009-01-01

    Fuel hazards have increased in forests across the United States because offire exclusion during the 20th century. Treatments used to reduce fuel buildup Illay affect wildlife. such as shrews. living 011 the forest floor. especially when treatments are applied repeatedly. From mid-May to mid-August 2006 and 2007.  we used drift fences...

  19. 5-year follow-up of a prospective clinical study on various types of core restorations.

    NARCIS (Netherlands)

    Creugers, N.H.J.; Mentink, A.G.B.; Fokkinga, W.A.; Kreulen, C.M.

    2005-01-01

    PURPOSE: This study tested whether: (1) the survival rate of cast post-and-core restorations is better than the survival of direct post-and-core restorations and post-free all-composite cores; and (2)the survival of these buildup restorations is influenced by the remaining dentin height after

  20. Statistical properties of the Stokes signal in stimulated Brillouin scattering pulse compressors

    NARCIS (Netherlands)

    Velchev, I.; Ubachs, W.M.G.

    2005-01-01

    Spontaneous scattering noise is incorporated as a build-up source in a fully transient stimulated Brillouin scattering (SBS) model. This powerful simulation tool is successfully applied for a quantitative investigation of the fluctuations in the output pulse duration of SBS pulse compressors. The

  1. JOURNEY TOWARDS ACTIVE LIFESTYLE AND SUCCESSFUL ...

    African Journals Online (AJOL)

    User

    (Fapohunda, 2013). The failures of pension schemes in the country have been attributed to poor pension fund administration, outright corruption; embezzlement of pension fund; inadequate build-up of funds and poor supervision, which has left pensioners with no option than struggling with their lifestyle after retirement.

  2. Study of gamma radiation shielding properties of ZnO−TeO2 glasses

    Indian Academy of Sciences (India)

    2017-07-25

    Jul 25, 2017 ... tellurite glasses should be beneficial from the point of proper gamma shield designs when intended to be used as radiation shields. Keywords. Mass attenuation coefficient; effective atomic number; electron density; exposure buildup factors; tellurite glass. 1. Introduction. High-energy gamma rays are a type ...

  3. Economic Recovery vs. Defense Spending.

    Science.gov (United States)

    De Grasse, Robert; Murphy, Paul

    1981-01-01

    Evaluates President Reagan's proposed military buildup in light of the cuts such expenditures would necessitate in approximately 300 domestic programs. Suggests that the dramatic proposed increase in military spending risks higher inflation and slower economic growth. Concludes with a plea for rethinking of Reagan's dramatic shift in national…

  4. Performance Of Irish Potato Varieties Under Aeroponic Conditions In ...

    African Journals Online (AJOL)

    Productivity of Irish potato (Solanum tuberosum) is constrained primarily by use of low quality seeds in Rwanda. Many field multiplication generations of vegetatively propagated basic seed result in build-up of seed-borne diseases and subsequent dissemination to new fields. Using soil-less media is an alternative to reduce ...

  5. Genetics Home Reference: adenosine deaminase deficiency

    Science.gov (United States)

    ... are produced in specialized lymphoid tissues including the thymus, which is a gland located behind the breastbone, and lymph nodes, which are found throughout the body. Lymphocytes in the blood and in lymphoid ... lymphocytes in the thymus are particularly vulnerable to a toxic buildup of ...

  6. Genetics Home Reference: purine nucleoside phosphorylase deficiency

    Science.gov (United States)

    ... nodes and then released into the blood. The thymus is a gland located behind the breastbone; lymph nodes are found throughout the body. Lymphocytes in the blood and in lymphoid tissues make up ... lymphocytes in the thymus are particularly vulnerable to a toxic buildup of ...

  7. Lance for injecting highly-loaded coal slurries into the blast furnace

    Energy Technology Data Exchange (ETDEWEB)

    Illuminati, D.

    1991-10-29

    A lance is used to inject fuel oil into a blast furnace. This simple design permits conversion of coal water and coal tar slurries to a fine mist at very low flow rates. This design prevents the build-up of deposits which increases service life and steadies the flow rate.

  8. Estimating ladder fuels: a new approach combining field photography with LiDAR

    Science.gov (United States)

    Heather Kramer; Brandon Collins; Frank Lake; Marek Jakubowski; Scott Stephens; Maggi Kelly

    2016-01-01

    Forests historically associated with frequent fire have changed dramatically due to fire suppression and past harvesting over the last century. The buildup of ladder fuels, which carry fire from the surface of the forest floor to tree crowns, is one of the critical changes, and it has contributed to uncharacteristically large and severe fires. The abundance of ladder...

  9. CATEGORIAS ESENCIALES PARA COMPRENDER LA EXISTENCIA DEL SER HUMANO Y SUS TRANSFORMACIONES EN LA PSICOLOGIA HUMANISTA EXISTENCIAL

    Directory of Open Access Journals (Sweden)

    Clara Ines Vega Palacio

    2010-06-01

    Full Text Available The current article appears as an intent to buildup a conceptual, punctual, and deep reflectionin the exercise of an enlightening thought aboutthe human being and his transformations, whatthe Humanistic-Existential psychology considersto be the principles to understand existence;four essential categories are approached beingthe capital elements for the research in theContemporary Transformations group.

  10. Phytoremediation: A green technology to remove environmental pollutants

    Science.gov (United States)

    Land, surface water, and ground water worldwide, are increasingly affected by contaminations from industrial, research experiments, military, and agricultural activities either due to ignorance, lack of vision, carelessness, or high cost of waste disposal and treatment. The rapid build-up of toxic p...

  11. Color Recovery Effect of Different Bleaching Systems on a ...

    African Journals Online (AJOL)

    2018-02-07

    [Downloaded free from http://www.njcponline.com on Wednesday, February 7, 2018, IP: 197.89.67.237] ... build-up. In general, these mouthwashes contain a low concentration of hydrogen peroxide (1.5%) and sodium hexametaphosphate, which protect the teeth surface ... was regularly monitored with the light intensity.

  12. Roller Locking Brake

    Science.gov (United States)

    Vranish, John M.

    1993-01-01

    Roller locking brake is normally braking rotary mechanism allowing free rotation when electromagnet in mechanism energized. Well suited to robots and other machinery which automatic braking upon removal of electrical power required. More compact and reliable. Requires little electrical power to maintain free rotation and exhibits minimal buildup of heat.

  13. Genetics Home Reference: cryptogenic cirrhosis

    Science.gov (United States)

    ... cirrhosis likely result from a condition called non-alcoholic fatty liver disease (NAFLD). In NAFLD, fat accumulates in the liver , impairing its function. If the fat buildup leads to ... called non-alcoholic steatohepatitis (NASH). Long term inflammation in people with ...

  14. Soil Organic Carbon Dynamics under Different Plantation Crops of ...

    African Journals Online (AJOL)

    Increasing the carbon sequestration potential of the soil is one of the ways to address the increasing build-up of greenhouse gases especially carbon dioxide. A study was conducted to assess the organic carbon pool under Young and Old tree plantations at Uhonmora, Edo State, Nigeria. The plantation species included ...

  15. CTR plasma engineering studies. Progress report, October 1, 1976--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Miley, G.H.

    1977-01-01

    Plasma engineering studies at the Fusion Studies Laboratory of the University of Illinois, Urbana IL are described that deal with: fusion-product transport in plasmas and associated effects in tokamaks, neutral-beam injection and plasma build-up in mirrors, and studies of aspects of alternate confinement concepts including field-reversed mirrors, field-reversed pinches, and twin-beam mirrors.

  16. Olujimi et al (10)

    African Journals Online (AJOL)

    DELL

    Water in each aquarium was changed at two days interval to prevent the build-up of metabolic wastes. The fish were fed twice daily with fish meal at 3 % body ... The control experiment was similarly set up in triplicates with aerated borehole water collected from the University. Acute toxicity test conducted followed the ...

  17. 46__300 - 305_Sagagi and Imam

    African Journals Online (AJOL)

    pc

    Corresponding author: ABSTRACT. Irrigation using wastewater is a very com. Excessive build-up of Potentially Toxic Eleme only result in soil pollution, but also lead to quality and safety. This uptake depends on th can be evaluated using the sequential extra. Community Bureau of Reference (B pseudototal extraction ...

  18. Stripping Paint From Exterior Wood Surfaces

    Science.gov (United States)

    Mark T. Knaebe

    2013-01-01

    Removing paint and other film-forming finishes is a time consuming and often difficult process. In some cases, finishes need to be removed prior to repainting; for example, if the old surface is covered with severely peeled or blistered paint or if excessive paint buildup has caused cross-grain cracking. You must also remove the finish before applying a penetrating...

  19. China Naval Modernization: Implications for U.S. Navy Capabilities - Background and Issues for Congress

    Science.gov (United States)

    2011-07-11

    has been bullying its neighbors over disputed claims in the South and East China Seas, while continuing an arms build-up across from Taiwan. In...all of those claims. In addition, two other states ( Peru and Ecuador) unlawfully claim a 200 nautical mile territorial sea, in which they purport to

  20. Multifractal analysis of earthquakes in Kumaun Himalaya and its ...

    Indian Academy of Sciences (India)

    Earthquakes in this region are mainly caused due to release of elastic strain energy. The Himalayan region can be attributed to .... the Himalayas and the aseismic slip rate simu- lated below the Higher Himalayas suggests that ..... observed power-law build-up of intermediate events before a great earthquake represent the ...

  1. Numerical continuum mechanics

    CERN Document Server

    Kukudzhanov, Vladimir N

    2013-01-01

    This work focuses on computational methods in continuum thermomechanics. The text is based on the author's lectures, which ensures a didactical and coherent buildup.The main emphasis is put on the presentation of ideas and qualitative considerations, illustrated by specific examples and applications. Conditions and explanations that are essential for the practical application of methods are discussed thoroughly.

  2. effect of abattoir waste on the physicochemical and bacteriological ...

    African Journals Online (AJOL)

    HOD

    The study involved the collection of water samples at the designated points from the New Artisan. River where the abattoir wastewaters are ... Keywords: Abattoir, wastewater, river, pollution, drinking water. 1. INTRODUCTION. Water quality is a ..... High TDS levels indicate hard water, which can cause scale build-up in ...

  3. Resolving the building blocks of galaxies in space and time

    NARCIS (Netherlands)

    Clauwens, B.J.F.

    2017-01-01

    We investigate the buildup of galaxies from various vantage points. The first two chapters focus on the stellar content of galaxies, especially the distribution of stellar masses at birth and potential variations therein in various galactic environments. We find that in some cases these inferred

  4. Experiment-Based Computational Investigation of Thermomechanical Stresses in Flip Chip BGA Using the ATC4.2 Test Vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Burchett, Steven N.; Nguyen, Luu; Peterson, David W.; Sweet, James N.

    1999-08-02

    Stress measurement test chips were flip chip assembled to organic BGA substrates containing micro-vias and epoxy build-up interconnect layers. Mechanical degradation observed during temperature cycling was correlated to a damage theory developed based on 3D finite element method analysis. Degradation included die cracking, edge delamination and radial fillet cracking.

  5. Unexpected Responses of autotrophs to nutrient loading: Influence of water residence time on eutrophication expression

    Science.gov (United States)

    Water residence time may critically influence the expression of estuarine eutrophication symptoms such as phytoplankton blooms, anoxia/hypoxia, build-up of organic matter, and altered community composition. While a conceptual model was developed in the late 1990’s; pioneer...

  6. Mapping tradeoffs in values at risk at the interface between wilderness and non-wilderness lands

    Science.gov (United States)

    Alan Watson; Roian Matt; Tim Waters; Kari Gunderson; Steve Carver; Brett Davis

    2009-01-01

    On the Flathead Indian Reservation in Montana, U.S., the Mission Mountains Tribal Wilderness is bordered by a buffer zone. To successfully improve forest health within that buffer zone and restore fire in the wilderness, the managing agency and the public need to work together to find solutions to increasingly threatening fuel buildups. A combination of qualitative,...

  7. analysis of pressure variation of fluid in bounded circular reservoirs ...

    African Journals Online (AJOL)

    user

    It is important to note that solutions from existing literature only state the pressure at the wellbore at a particular time but this work predicts the .... computational mathematics involved. 6. TIME APPROXIMATION. For a given ..... [11] Ramey, H.J., Jr. and Cobb, W. M. A General Pressure. Build-up Theory for a Well in a Closed ...

  8. Root diseases in coniferous forests of the Inland West: potential implications of fuels treatments

    Science.gov (United States)

    Raini C. Rippy; Jane E. Stewart; Paul J. Zambino; Ned B. Klopfenstein; Joanne M. Tirocke; Mee-Sook Kim; Walter G. Thies

    2005-01-01

    After nearly 100 years of fire exclusion, introduced pests, and selective harvesting, a change in forest composition has occurred in many Inland West forests of North America. This change in forest structure has frequently been accompanied by increases in root diseases and/or an unprecedented buildup of fuels. Consequently, many forest managers are implementing plans...

  9. Clutter Height Variation Effects on Frequency Dependen Path Loss ...

    African Journals Online (AJOL)

    Clutter Height Variation Effects on Frequency Dependen Path Loss Models at UHF Bands in Build-Up Areas. ... With the aforementioned, we believe the results and observations presented would provide guide to radio system engineers in making informed choices on the applicability and predictability of such models in the ...

  10. Grid-Parity Solar Power for Department of Defense Installations

    Science.gov (United States)

    2014-02-01

    Demonstration N2O Nitrous Oxide NH4 Methane NPV Net Present Value O&M Operations and Maintenance OMS Online Monitoring System PTC PVUSA Test...of livestock (e.g. sheep ) to prevent buildup of grass and weeds under and around panels. • Design teams should consider variations in panel

  11. The effect of a fiber reinforced cavity configuration on load bearing capacity and failure mode of endodontically treated molars restored with CAD/CAM resin composite overlay restorations

    NARCIS (Netherlands)

    Rocca, G.T.; Saratti, C.M.; Cattani-Lorente, M.; Feilzer, A.J.; Scherrer, S.; Krecji, I.

    2015-01-01

    Objectives To evaluate the fracture strength and the mode of failure of endodontically treated molars restored with CAD/CAM overlays with fiber reinforced composite build-up of the pulp chamber. Methods 40 Devitalized molars were cut over the CEJ and divided into five groups (n = 8). The pulp

  12. Evaluation of efficacy of restorative dental treatment provided under general anesthesia at hospitalized pediatric dental patients of Isfahan

    Directory of Open Access Journals (Sweden)

    Alireza Eshghi

    2012-01-01

    Conclusion: Stainless steel crown restorations had significantly better results vs other posterior restorations. The failure rates of stainless steel crown and anterior composite resin build-up restorations did not correlate with the time of follow-up in comparison of other restorations.

  13. Choline evokes fluid secretion by perfused rat mandibular gland without desensitization

    DEFF Research Database (Denmark)

    Murakami, M; Novak, I; Young, J A

    1986-01-01

    of muscarinic receptors, but it is unclear why choline does not evoke tachyphylaxis. The response to choline allows us to exclude a number of the possible causes of tachyphylaxis that have previously been considered, so that an excessive buildup of cytosolic free Ca now remains as the most likely cause...

  14. Tunable Optical Sources.

    Science.gov (United States)

    1980-11-01

    crystals were grown from melts containing excess Li20, interlace partitioning and build-up was expected. To prevent breakdown and constitutional supercooling...1" Journ. Appl. Phys. 43(3), p.1042-1049 (1972). 15. D. von der Linde, A.M. Glass and K.F. Rodgers, "Multi- photon Photo-refractive Processes for

  15. Recapitalizing the Air Force Intellect: Essays on War, Airpower, and Military Education

    Science.gov (United States)

    2008-05-01

    amphibious assault and subsequent force buildup, the hedgerow country behind the beaches was just about the worst imaginable terrain for subsequent breakout...fact illustrated in the bloody, yard-by-yard struggle through the hedgerows that lasted for nearly two months.13 Another example is found in US Army

  16. Filtration of Nanoparticles: Evolution of Cake Structure and Pressure-Drop

    DEFF Research Database (Denmark)

    Elmøe, Tobias Dokkedal; Tricoli, Antonio; Grunwaldt, Jan-Dierk

    2009-01-01

    with constant solid volume fraction began to form, accompanied with build-up of pressuredrop which was in excellent agreement with classic cake filtration theory. An expression for the solid volume fraction of the cake (fsd,c) was obtained as a sole function of Pe. In addition, the filtration efficiency became...

  17. The Use of an Experimental Design Approach to Investigate the ...

    African Journals Online (AJOL)

    When a conventional starting, lighting and ignition (SLI) lead acid battery is exposed to a high rate partial state of charge (HRPSoC) cycling, it would experience a build-up of irreversible PbSO4 on the negative plate, resulting in capacity loss and electrode damage. The addition of certain graphites to the negative paste mix ...

  18. Southeastern USA regional landscape patterns and population dynamics of the stink bug, Euchistus servus

    Science.gov (United States)

    Introduction: The brown stink bug, Euschistus servus is an economically important pest of many agronomic crops in the southern USA, motivating the study of factors influencing population build-up in agricultural regions and landscapes to facilitate management. Methods: ArcGIS was used to characteriz...

  19. Technical Support for Implementation of Aluminum Vapor Deposition Technology

    Science.gov (United States)

    1996-05-01

    used on components of the Patriot, Amraam, and Lantim projects. 10 Other specialized applications of AIVD coatings include coating of ferrite ...conditioned water that would prevent buildup of calcium scale in the cooling system. Other recommendations included construction of a clean-room large enough to

  20. Preventing or predicting cyanobacterial blooms : Iron addition as a whole lake restoration tool

    NARCIS (Netherlands)

    Immers, A.K.

    2014-01-01

    Internal phosphorus loading has become a major problem in many freshwater lakes due to the build-up of nutrient stocks in the sediment over the past decades. Iron is a natural capping agent which naturally binds to P and can enhance sediment P binding capacity. Various restoration experiments using

  1. Naval Trends in Asean. Is There a New Arms Race?

    Science.gov (United States)

    1995-12-01

    Global military spending is decreasing. However this trend does not apply to some regions of the world, specifically Southeast Asia. This thesis...describes the ongoing naval arms buildup in this region and examines why it is occurring when the rest of the world is decreasing military spending . Next

  2. Optimisation potential of sucker rod deep drilling systems in petroleum production at Brown Fields; Optimierungspotential von Gestaengetiefpumpensystemen bei der Erdoelfoerderung von Brown Fields

    Energy Technology Data Exchange (ETDEWEB)

    Sam, G.; Kass, M.; Rice, D. [Rohoel-Aufsuchungs AG (RAG), Gampern (Austria)

    2007-09-13

    Optimised operation of sucker rod deep drilling systems is a decisive criterion for economically efficient production from older wells with liquid build-up (Brown Fields). Possibilities for optimising the system as a whole are reviewed from different angles (software, hardware). Design software, design methods, material problems, and corrosion prevention are gone into. (orig.)

  3. Heavy metals accumulation in edible part of vegetables irrigated ...

    African Journals Online (AJOL)

    Hassana Ibrahim Mustapha

    In this present study, the quality of municipal wastewater used for irrigation of spinach was investigated for its heavy metal build-up. .... digested samples were filtered with a 0.45 µm pore size cellulose nitrate membrane filter paper. ... irrigation with partially treated or untreated sewage. This was reported by Farooq et al.

  4. MEDICINAL, PHARMACOLOGICAL AND PHYTOCHEMICAL ...

    African Journals Online (AJOL)

    DR. AMINU

    2013-06-01

    Jun 1, 2013 ... 100cm long, surrounding a thick stem. A. comosus is an example of .... cells. Free radicals have been shown to promote the artery plaque build-up of atherosclerosis and diabetic heart disease, caused the airway spasm that leads to asthma attacks ... pain and disability seen in osteoarthritis and rheumatoid ...

  5. 615-IJBCS-Article-Jume Seydu

    African Journals Online (AJOL)

    DR GATSING

    weevils. This was the case because longer exposures at temperatures above 40 oC are lethal to insect pests (Gewinner et al., 1996). DISCUSSION. Temperature changes in the solar dryer. The result revealed a rapid build-up of heat energy in the solar dryer as soon as it was placed in the sun. This resulted in the increase.

  6. Dietary fats explained

    Science.gov (United States)

    ... and fatty meats. Some vegetable oils, such as coconut, palm, and palm kernel oil, also contain saturated fats. These fats are solid at room temperature. A diet high in saturated fat increases cholesterol buildup in your arteries (blood vessels). Cholesterol is ...

  7. On the Presentation of Wave Phenomena of Electrons with the Young-Feynman Experiment

    Science.gov (United States)

    Matteucci, Giorgio

    2011-01-01

    The Young-Feynman two-hole interferometer is widely used to present electron wave-particle duality and, in particular, the buildup of interference fringes with single electrons. The teaching approach consists of two steps: (i) electrons come through only one hole but diffraction effects are disregarded and (ii) electrons come through both holes…

  8. Organizational barriers

    Science.gov (United States)

    Kenneth S. Blonski

    1995-01-01

    One of the traditional roles that prescribed fire has played in the fire management arena is reduction of hazardous fuel buildups under controlled, well-defined environmental conditions. However, our ability to use this tool effectively is blocked by many barriers. The preceding panel discussion about the causes of limited success in implementing prescribed burning...

  9. Download this PDF file

    African Journals Online (AJOL)

    Variations in diurnal light intensities affected the occurrence of the peaks. ... Four apterous R. maidis adults were left on each potted 18 hr of light the developmental period was reduced to millet seedling and .... weeks is substantially longer than those reported for other the aphid has a high rate of population build-up. Rapid.

  10. Developing resilient ponderosa pine forests with mechanical thinning and prescribed fire in central Oregon's pumice region

    Science.gov (United States)

    Matt D. Busse; P.H. Cochran; William E. Hopkins; William H. Johnson; Gregg M. Riegel; Gary O. Fiddler; Alice W. Ratcliff; Carol J. Shestak

    2009-01-01

    Thinning and prescribed burning are common management practices for reducing fuel buildup in ponderosa pine forests. However, it is not well understood if their combined use is required to lower wildfire risk and to help restore natural ecological function. We compared 16 treatment combinations of thinning, prescribed fire, and slash retention for two decades...

  11. Recent results on Ion Cyclotron Wall Conditioning in mid and large size tokamaks

    NARCIS (Netherlands)

    Douai, D.; Lyssoivan, A.; Philipps, V.; Rohde, V.; Wauters, T.; Blackman, T.; Bobkov, V.; Bremond, S.; Brezinsek, S.; Clairet, F.; De La Cal, E.; Coyne, T.; Gauthier, E.; Gerbaud, T.; Graham, M.; Jachmich, S.; Joffrin, E.; Koch, R.; Kreter, A.; Laengner, R.; Lamalle, P. U.; Lerche, E.; Lombard, G.; Maslov, M.; Mayoral, M. L.; Miller, A.; Monakhov, I.; Noterdaeme, J. M.; Ongena, J.; Paul, M. K.; Pegourie, B.; Pitts, R.A.; Plyusnin, V.; Schüller, F. C.; Sergienko, G.; Shimada, M.; Sirinelli, A.; Suttrop, W.; Sozzi, C.; Tsalas, M.; Tsitrone, E.; Unterberg, B.; Van Eester, D.

    2011-01-01

    Wall conditioning techniques applicable in the presence of permanent toroidal magnetic field will be required for the operation of ITER, in particular for recovery from disruptions, vent and air leak, isotopic ratio control, recycling control and mitigation of the tritium inventory build-up. Ion

  12. The effects of updating ability and knowledge of reading strategies on reading comprehesion

    NARCIS (Netherlands)

    Muijselaar, M.M.L.; de Jong, P.F.

    2015-01-01

    Updating ability and reading strategies are considered as important factors in the buildup of a mental model of a text. However, only few studies examined the relation of updating and knowledge of reading strategies with reading comprehension. The aim of the current study was to investigate the

  13. Exact solutions to the Boltzmann equation by mapping the scattering integral into a differential operator

    Energy Technology Data Exchange (ETDEWEB)

    Zabadal, Jorge; Borges, Volnei; Van der Laan, Flavio T., E-mail: jorge.zabadal@ufrgs.br, E-mail: borges@ufrgs.br, E-mail: ftvdl@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Departamento de Engenharia Mecanica. Grupo de Pesquisas Radiologicas; Ribeiro, Vinicius G., E-mail: vinicius_ribeiro@uniritter.edu.br [Centro Universitario Ritter dos Reis (UNIRITTER), Porto Alegre, RS (Brazil); Santos, Marcio G., E-mail: phd.marcio@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Tramandai, RS (Brazil). Departamento Interdisciplinar do Campus Litoral Norte

    2015-07-01

    This work presents a new analytical method for solving the Boltzmann equation. In this formulation, a linear differential operator is applied over the Boltzmann model, in order to produce a partial differential equation in which the scattering term is absent. This auxiliary equation is solved via reduction of order. The exact solution obtained is employed to define a precursor for the buildup factor. (author)

  14. Status Of Cotton Aphid, Aphis gssypii

    African Journals Online (AJOL)

    Electrophoretic banding patterns and quantitative analysis of carboxylesterases from cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) populations infesting vegetables in southern Ghana revealed a nation-wide build-up and spread of resistant genes in most vegetable growing areas. Most aphid populations ...

  15. Formulating a natural colorant containing wax for a one-step color-add application for fresh citrus

    Science.gov (United States)

    In Florida, early season citrus fruits usually reach full maturity in terms of internal quality while their peel often does not turn orange in color after degreening due to insufficient buildup of carotenoids. For huanglongbing-affected orange trees, the fruit may never turn orange the entire harves...

  16. Rubella in South Africa: An impending Greek tragedy? | Schoub ...

    African Journals Online (AJOL)

    Background. The incidence of congenital rubella syndrome (CRS) is unknown in South Africa. There is evidence that it may be significant and largely undetected, particularly in the upper socio-economic group. This may be due to incomplete routine administration of MMR vaccine in infancy and a build-up of susceptible ...

  17. Understanding the effects of fire management practices on forest health: implications for weeds and vegetation structure

    Science.gov (United States)

    Anne E. Black; Peter Landres

    2012-01-01

    Current fire policy to restore ecosystem function and resiliency and reduce buildup of hazardous fuels implies a larger future role for fire (both natural and human ignitions) (USDA Forest Service and U.S. Department of the Interior 2000). Yet some fire management (such as building fire line, spike camps, or helispots) potentially causes both short- and longterm...

  18. Understanding the effects of fire management practices on forest health: Implications for weeds and vegetation structure (Project INT-F-04-01) [Chapter 14

    Science.gov (United States)

    Anne E. Black; Peter Landres

    2011-01-01

    Current fire policy to restore ecosystem function and resiliency and reduce buildup of hazardous fuels implies a larger future role for fire (both natural and human ignitions) (USDA and USDOI 2000). Yet some fire management (such as building fire line, spike camps, or heli-spots) potentially causes both short- and long-term impacts to forest health. In the short run,...

  19. Controlled Hyperthermia with MRI-guided Focused Ultrasound

    DEFF Research Database (Denmark)

    Hokland, Steffen; Salomir, Rares; Pedersen, Michael

    doses sufficient to induce cellular deactivation thermotherapy is still regarded as an experimental treatment. In contrast to other thermo-therapeutic modalities Focused Ultrasound (FUS) may be employed non-invasively to deliver a highly localized thermal build-up in deep seated regions of the body...

  20. Desorption of SVOCs from Heated Surfaces in the Form of Ultrafine Particles

    DEFF Research Database (Denmark)

    Wallace, Lance A.; Ott, Wayne R.; Weschler, Charles J.

    2017-01-01

    of the accumulation rate of SVOCs on surfaces were similar to those in studies of organic film buildup on indoor windows. Transfer of skin oils by touching the glass or foil surfaces, or after washing the glass surface with detergent and bare hands, was also observed, with measured particle production comparable...